JP6563756B2 - A method for producing a molded body, a method for producing an oxygen sensor, and a method for producing a spark plug. - Google Patents

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, a grinding apparatus that manufactures a molded body by processing a workpiece by moving a grindstone based on a preset movement pattern is known (see, for example, Patent Document 1).

JP-A-10-156718

  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 making quality and productivity of a molded object compatible.

This invention made | formed in order to achieve the said objective is a manufacturing method of the molded object shape | molded by grinding the to-be-processed member which is a member used as a process target with a grindstone.
And the manufacturing method of the molded object of this invention is equipped with a 1st roughening process, a 2nd roughing process, a 1st finishing process, and a 2nd finishing process.

  In the first roughing step, the roughing grindstone, which is a grindstone for grinding the workpiece to have a preset roughing shape, is moved so as to approach the workpiece at a preset first moving speed. Grind the workpiece with a rough grinding wheel.

  In the second roughing step, after the first roughing step is completed, the roughing grindstone is moved so as to approach the workpiece at a second moving speed set in advance so as to be different from the first moving speed. Grind the workpiece with a grinding wheel.

  In the first finishing step, after the second roughing step is finished, the workpiece to be machined is a grinding wheel that is a grinding stone for grinding the workpiece to have a preset finished shape at a preset third moving speed. The workpiece is ground with a finishing grindstone by moving it closer to.

  In the second finishing step, after the first finishing step is finished, the finishing grindstone is moved by the finishing grindstone by moving the finishing grindstone so as to approach the workpiece at a fourth moving speed that is set differently from the third moving speed. Grind the workpiece.

  The method for producing the molded body of the present invention thus configured is at least 2 in both the case of grinding with a roughing grindstone so as to obtain a rough shape and the case of grinding with a finishing grindstone so as to obtain a finished shape. Change the movement speed in stages. For this reason, the manufacturing method of the molded object of this invention can make compatible the quality and productivity of the molded object shape | molded with the roughing grindstone by adjusting a 1st moving speed and a 2nd moving speed. Furthermore, the manufacturing method of the molded object of this invention can make compatible the quality and productivity of the molded object shape | molded with the finishing grindstone by adjusting a 3rd moving speed and a 4th moving speed. As mentioned above, the manufacturing method of the molded object of this invention can make the quality and productivity in the case of manufacturing a molded object using a roughing grindstone and a finishing grindstone compatible.

  Moreover, in the manufacturing method of the molded object of this invention, a 2nd roughing process is the last process of grinding a workpiece with a roughing grindstone, and a 1st finishing process grinds a workpiece with a finishing grindstone. In the case of the first step, the second movement speed may be smaller than the third movement speed. The method for producing a molded article of the present invention configured as described above can improve productivity when a workpiece is ground with a finishing grindstone.

  In the method for producing a molded body of the present invention, the distance traveled by the roughing grindstone in the first roughing process is defined as the first travel distance, and the distance traveled by the roughing grindstone in the second roughing process is defined as the second travel distance. The first movement speed may be greater than the second movement speed, and the first movement distance may be longer than the second movement distance. The manufacturing method of the molded body of the present invention configured as described above can improve productivity when a workpiece is ground with a roughing grindstone.

  In the method for producing a molded body of the present invention, the third moving distance is the distance that the finishing whetstone moves in the first finishing step, and the third moving distance is the distance that the finishing whetstone moves in the second finishing step. The moving speed may be greater than the fourth moving speed, and the third moving distance may be longer than the fourth moving distance. The method for producing a molded article of the present invention configured as described above can improve productivity when a workpiece is ground with a finishing grindstone.

  In the method for producing a molded body of the present invention, the distance traveled by the roughing grindstone in the first roughing process is defined as the first travel distance, and the distance traveled by the roughing grindstone in the second roughing process is defined as the second travel distance. The first movement speed may be greater than the second movement speed, and the first movement distance may be shorter than the second movement distance. The method for producing a molded body of the present invention configured as described above can improve the quality of the molded body when a workpiece is ground with a roughing grindstone.

  In the method for producing a molded body of the present invention, the third moving distance is the distance that the finishing whetstone moves in the first finishing step, and the third moving distance is the distance that the finishing whetstone moves in the second finishing step. The moving speed may be larger than the fourth moving speed, and the third moving distance may be shorter than the fourth moving distance. The method for producing a molded body of the present invention configured as described above can improve the quality of the molded body when a workpiece is ground with a finishing grindstone.

  In addition, the oxygen sensor manufacturing method for manufacturing the molded body that becomes the detection element of the oxygen sensor by the manufacturing method of the present invention has the same effects as the manufacturing method of the molded body of the present invention. It is possible to balance the sex.

  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 quality and production of the spark plug It is possible to balance the sex.

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 the grindstones 12 and 13. 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. 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. It is a figure which shows the movement pattern of the grindstones 12 and 13 in another embodiment.

(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 supported by the support pin 25 so as to be rotatable about the support pin 25 as a rotation axis by inserting the support pin 25 into a recessed portion formed therein.

  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. 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. 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 being inserted into the turntable 11.

  The drive unit 17 includes motors 31, 32, 33, 34, 35, 36, 37, 38, 39, and 40. 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 rotating the grindstone 13. The motor 35 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 36 is a drive source that supplies a drive force for rotating the presser roller 14. The motor 37 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 38 is a drive source that supplies a drive force for rotating the presser roller 15. The motor 39 is a driving source that supplies a driving force for moving the presser roller 15 back and forth with respect to the grindstone 13. The motor 40 is a driving source that supplies a driving force for moving the supply / extraction unit 16.

  The drive mechanism 18 includes a rotation mechanism 41, a rotation mechanism 42, a movement mechanism 43, a rotation mechanism 44, a movement mechanism 45, a rotation mechanism 46, a movement mechanism 47, a rotation mechanism 48, a movement mechanism 49, A moving mechanism 50.

  The rotation mechanism 41 transmits the driving force of the motor 31 to the turntable 11 to rotate the turntable 11. The rotating mechanism 42 transmits the driving force of the motor 32 to the grindstone 12 to rotate the grindstone 12. The moving mechanism 43 transmits the driving force of the motor 33 to the grindstone 12 to move the grindstone 12 forward or backward. The rotating mechanism 44 transmits the driving force of the motor 34 to the grindstone 13 to rotate the grindstone 13. The moving mechanism 45 transmits the driving force of the motor 35 to the grindstone 13 to move the grindstone 13 forward or backward.

  The rotation mechanism 46 transmits the driving force of the motor 36 to the presser roller 14 to rotate the presser roller 14. The moving mechanism 47 transmits the driving force of the motor 37 to the presser roller 14 to move the presser roller 14 forward or backward. The rotation mechanism 48 transmits the driving force of the motor 38 to the presser roller 15 to rotate the presser roller 15. The moving mechanism 49 transmits the driving force of the motor 39 to the presser roller 15 to move the presser roller 15 forward or backward.

  The moving mechanism 50 transmits the driving force of the motor 40 to the supply / extraction unit 16 to move the supply / extraction unit 16. Specifically, when the moving mechanism 50 receives a workpiece from the previous process facility, the moving mechanism 50 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. In addition, after the grinding by the grinding device 1, the moving mechanism 50 starts from the vicinity of the support pin 25 located at a preset workpiece take-out 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 51, a ROM 52, a RAM 53, a signal input / output unit 54, 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 40 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 40 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 51 of the control device 22 first determines whether or not the workpiece 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, this roughing movement pattern is set by the moving distance of the grindstone 12 from the roughing grindstone standby position and the moving speed of the grindstone 12. Specifically, when the forward movement is started, first, the moving speed of the grindstone 12 is increased at a constant acceleration until reaching a preset initial speed V1, and then the initial speed V1 is maintained. When the moving distance from the roughing grindstone standby position reaches a preset initial shift start distance d1, the moving speed of the grindstone 12 is set to a final speed V2 set in advance so as to be smaller than the initial speed V1. Decrease at a constant deceleration. As a result, when the moving distance from the roughing grindstone standby position reaches the preset initial shift end distance d2, the moving speed of the grindstone 12 becomes the final speed V2. Thereafter, when the moving distance from the roughing grindstone standby position reaches a preset final shift start distance d3, the moving speed of the grindstone 12 is decreased at a constant deceleration until it reaches zero. Thereby, when the moving distance from the roughing grindstone standby position reaches the preset final shift end distance d4, the moving speed of the grindstone 12 becomes zero.

  When the forward movement of the grindstone 12 is completed, as shown in FIG. 4, the presser roller 14 and the grindstone 12 are moved backward in S50. As a result, the presser roller 14 moves to the roughing roller 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. 5B, the finishing movement pattern is set by the moving distance of the grindstone 13 from the finishing grindstone standby position and the moving speed of the grindstone 13. Specifically, when the forward movement is started, first, the moving speed of the grindstone 13 is increased at a constant acceleration until reaching an initial speed V3 set in advance so as to be larger than the final speed V2 of the roughing movement pattern. After that, the initial speed V3 is maintained. When the moving distance from the finishing wheel standby position reaches the preset initial shift start distance d5, the moving speed of the grindstone 13 is set to the final speed V4 set in advance so as to be smaller than the initial speed V3. Decrease at a constant deceleration. Thus, when the moving distance from the finishing grindstone standby position reaches the preset initial shift end distance d6, the moving speed of the grindstone 13 becomes the final speed V4. Thereafter, when the moving distance from the finishing grindstone standby position reaches a preset final shift start distance d7, the moving speed of the grindstone 13 is decreased at a constant deceleration until it reaches zero. Thereby, when the moving distance from the finishing grindstone standby position reaches the preset final shift end distance d8, the moving speed of the grindstone 13 becomes zero.

  When the forward movement of the grindstone 13 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 14 moves to the finishing roller standby position, and the grindstone 13 moves to the finishing grindstone standby position.

The manufacturing method of the detection element 102 configured as described above includes a first roughing step, a second roughing step, a first finishing step, and a second finishing step.
In the first roughing step, the grindstone 12 for grinding the unground workpiece WK1 so as to have a preset detection element rough shape is moved so as to approach the unground workpiece WK1 at a preset initial speed V1. 12, the unground workpiece WK1 is ground (S40).

  In the second roughing process, after the first roughing process is completed, the grindstone 12 is moved so as to approach the unground workpiece WK1 at a final speed V2 set in advance so as to be different from the initial speed V1. The unground workpiece WK1 is ground (S40).

  In the first finishing process, after the second roughing process is completed, the grindstone 13 that grinds the roughing work WK2 so as to have a preset detection element finish shape approaches the roughing work WK2 at a preset initial speed V3. Thus, the rough work WK2 is ground with the grindstone 13 (S80).

  In the second finishing process, after the first finishing process is finished, the roughing workpiece WK2 is moved by the grindstone 13 by moving the grindstone 13 so as to approach the roughing workpiece WK2 at a preset final speed V4 different from the initial speed V3. Is ground (S80).

  As described above, the manufacturing method of the detection element 102 has a movement speed in at least two stages both in the case of grinding with the grindstone 12 so as to obtain a rough shape and in the case of grinding with the grindstone 13 so as to obtain a finished shape. Change. For this reason, the manufacturing method of the detection element 102 can balance the quality and productivity of the detection element 102 formed by the grindstone 12 by adjusting the initial speed V1 and the final speed V2. Furthermore, the manufacturing method of the detection element 102 can achieve both the quality and productivity of the detection element 102 formed by the grindstone 13 by adjusting the initial speed V3 and the final speed V4. From the above, the manufacturing method of the detection element 102 can achieve both the quality and productivity when the detection element 102 is manufactured using the grindstones 12 and 13.

  In the method for manufacturing the detecting element 102, the second roughing step is the last step of grinding the unground workpiece WK1 with the grindstone 12, and the first finishing step is the first step of grinding the rough workpiece WK2 with the grindstone 13. This is a process, and the final speed V2 is smaller than the initial speed V3. Thereby, productivity at the time of grinding the rough workpiece WK2 with the grindstone 13 can be improved.

  In the method for manufacturing the detection element 102, the distance that the grindstone 12 moves in the first roughing process (that is, the initial shift end distance d2) is the first moving distance, and the distance that the grindstone 12 moves in the second roughing process. (That is, the distance (d4-d2)) is the second movement distance, the initial speed V1 is greater than the final speed V2, and the first movement distance is longer than the second movement distance. Thereby, productivity when grinding the unground workpiece WK1 with the grindstone 12 can be improved.

  In the manufacturing method of the detecting element 102, the distance that the grindstone 13 moves in the first finishing process (that is, the initial shift end distance d6) is the third moving distance, and the distance that the grindstone 13 moves in the second finishing process is the first distance. As the four moving distances (that is, the distance (d8-d6)), the initial speed V3 is larger than the final speed V4, and the third moving distance is longer than the fourth moving distance. Thereby, productivity at the time of grinding the rough workpiece WK2 with the grindstone 13 can be improved.

  In the embodiment described above, the unground workpiece WK1 and the rough workpiece WK2 are workpieces according to the present invention, the detection element 102 is a molded body according to the present invention, the grindstone 12 is a rough grindstone according to the present invention, and the grindstone 13 is a finish according to the present invention. It is a grindstone.

Moreover, the process of S40 is the 1st roughening process and 2nd roughing process in this invention, and the process of S80 is the 1st finishing process and 2nd finishing process in this invention.
The initial speed V1, the final speed V2, the initial speed V3, and the final speed V4 are respectively the first movement speed, the second movement speed, the third movement speed, and the fourth movement speed in the present invention.

(Second Embodiment)
A second embodiment of the present invention will be described below with reference to the drawings.
The spark plug 201 according to 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. 7, 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 mounted on the engine head mounting portion, the gasket 211 is crushed and deformed between the seat 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 according to 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 roughing workpiece WK11 in FIG. 8). 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 according to the second embodiment grinds a workpiece (see rough cutting workpiece WK11 in FIG. 8) ground to an insulator roughing shape into a predetermined insulator finishing shape (see finishing workpiece WK12 in FIG. 8). 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 both the quality and productivity when the insulator 202 is manufactured using the grindstones 12 and 13 are achieved. Can do.

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, as shown in FIGS. 5A and 5B, the initial shift end distance (see distances d2 and d6) is changed from the final shift end distance (see distances d4 and d8) to the initial position. A value larger than the subtraction value obtained by subtracting the shift end distance (that is, (d4-d2) or (d8-d6)) is shown. However, as shown in FIG. 9, the initial shift end distance (see distance d12) is obtained by subtracting the initial shift end distance from the final shift end distance (see distance d14) (ie, (d14-d12). Thus, the quality of the roughing work WK2 formed by grinding the work with the grindstone 12 can be improved, and the finished work WK3 formed by grinding the work with the grindstone 13 can be improved. Can improve the quality.

  Moreover, in the said embodiment, although what changed the moving speed of the grindstones 12 and 13 was shown in two steps, you may make it change a moving speed in three steps or more.

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 DESCRIPTION OF SYMBOLS 101 ... Oxygen sensor 102 ... Detection element 201 ... Spark plug 202 ... Insulator, WK1 ... Unground workpiece, WK11 ... Roughing workpiece, WK12 ... Finishing workpiece, WK2 ... Roughing workpiece, WK3 ... Finishing workpiece

Claims (5)

A manufacturing method of a molded body formed by grinding a workpiece to be processed with a grindstone,
The roughing grindstone is moved by moving the roughing grindstone, which is the grindstone for grinding the workpiece to a preset roughing shape, at a first preset moving speed so as to approach the workpiece. A first roughing step of grinding the workpiece by:
After the first roughing step is completed, the roughing grindstone is moved by moving the roughing grindstone so as to approach the workpiece at a second moving speed set in advance different from the first moving speed. A second roughing step of grinding the workpiece with
After the second roughing step is finished, the finishing grindstone, which is the grindstone for grinding the workpiece to have a preset finish shape, approaches the workpiece at a preset third moving speed. A first finishing step of grinding the workpiece with the finishing grindstone by moving the workpiece,
After the first finishing step is completed, the finishing grindstone is moved by the finishing grindstone by moving the finishing grindstone so as to approach the workpiece at a fourth moving speed that is set differently from the third moving speed. A second finishing step of grinding the workpiece,
The distance that the finishing grindstone moves in the first finishing step is the third moving distance, and the distance that the finishing grindstone moves in the second finishing step is the fourth moving distance.
The third movement speed is greater than said fourth moving velocity, and the third travel distance rather longer than the fourth distance traveled,
In the second finishing step, when the moving distance of the finishing grindstone reaches a preset final shift start distance, the moving speed of the finishing grindstone is decreased at a constant deceleration until it reaches zero, and a preset speed change is performed. A method for producing a molded body , wherein the moving speed of the finishing grindstone becomes zero when the end position is reached . The second roughing step is a final step of grinding the workpiece with the roughing grindstone,
The first finishing step is an initial step of grinding the workpiece with the finishing grindstone,
The method for producing a molded body according to claim 1, wherein the second moving speed is smaller than the third moving speed. The distance that the roughing grindstone moves in the first roughing process is a first movement distance, the distance that the roughing grindstone moves in the second roughing process is a second movement distance,
3. The method for manufacturing a molded body according to claim 1, wherein the first movement speed is greater than the second movement speed, and the first movement distance is longer than the second movement distance. .   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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