JP2001185325A - Manufacturing apparatus and method of center electrode for spark plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus and method of a center electrode for a spark plug which can cut down with failure rate at insertion stage before applying turning process for a center electrode. SOLUTION: By detecting suitability of slide volume of a slide member 3 with a position detecting means 32 accompanied by insertion of a center electrode W, suitability of pinch-holding position of the center electrode W can be detected at an insertion stage before a turning process is applied to the center electrode W. Therefore, the number of defective goods can be restrained not only in case of under insertion of the electrode as well as insufficient length of the electrode but also in case of over insertion of the electrode as well as excessive length of the electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for manufacturing a center electrode for a spark plug and a method for manufacturing a center electrode for a spark plug.

[0002]

2. Description of the Related Art FIG. 11 schematically shows an example of a conventional manufacturing apparatus for turning a center electrode of a spark plug. A center electrode W having a total length 1 is inserted into the center hole 14 passing through the center of the spindle (rotating gripping part) 1 from the tool post 10 side in the axial direction thereof (push size).
When only L is inserted, inside the center hole 14, the front end face in the insertion direction of the center electrode contacts the rear end face in the insertion direction of the sensor pin 13b. The sensor pin 13b moves by being pushed in the insertion direction, and the front end in the insertion direction protruding from the center hole 14 reaches the sensor unit 3. The sensor section 3 is fixed to a mounting table (not shown), has an optical axis substantially perpendicular to the insertion direction of the center electrode (hereinafter, also simply referred to as the insertion direction), and
And a transmissive photoelectric sensor 32 having a light receiver 32b. The transmission type photoelectric sensor 32 is connected to the sensor pin 13.
When the front end of the insertion direction b is detected, a completion signal of insertion of the center electrode is issued, and the chuck mechanism 12 of the spindle 1 rotatably holds the center electrode. Thereafter, a turning process is performed on a portion of the center electrode projecting rearward in the insertion direction from the chuck mechanism 12 (see FIG. 11A). Note that represents the dimension from the insertion direction front end face of the center electrode W to the gripping position the center of the chuck mechanism 12 gripping dimension x, the specified dimensions as defined gripping dimensions x _0.

In order to improve spark erosion resistance, the center electrode of the spark plug is laminated with a noble metal tip on the electrode base material at the end thereof, and the electrode base material and the noble metal tip are welded by resistance welding or the like. There is a type that joins to form a noble metal ignition portion. The turning is performed for the purpose of, for example, deburring a weld bead formed at the time of such a welding connection.

[0004]

Here, the insertion dimension (indentation dimension) L and the total length 1 of the center electrode W are predetermined to be constant for each model number in order to improve production efficiency. For example, when the insertion dimension of the center electrode is insufficient (L '<L) due to the hooking of the center electrode inside the center hole 14, etc.
The transmission type photoelectric sensor 32 does not detect the front end of the sensor pin 13b in the insertion direction, and is notified of a center electrode insertion error signal instead of the center electrode insertion completion signal (see FIG. 11B). On the other hand, when the insertion dimension of the center electrode becomes excessively large (L "> L), such as when the pushing force is too large, the transmission-type photoelectric sensor 32 senses the front end of the sensor pin 13b in the insertion direction and detects the center electrode. As in the case where the insertion dimension is normal (L), a completion signal of insertion of the center electrode is issued, that is, when the insertion of the center electrode is excessive, turning cannot be distinguished from the case where the insertion is normal, and turning is started, and FIG. As shown in c), the cutting tool may not be hooked on the center electrode, or may be turned at a position other than the specified position, resulting in a defective product.

[0005] A similar problem also occurs when products of different model numbers are mixed and a center electrode longer than the specified length is inserted. When the insertion dimension of the center electrode is normal (L) and the center electrode is smaller than the specified length l (l '<l), the transmission type photoelectric sensor 32 does not detect the front end of the sensor pin 13b in the insertion direction, Instead of the center electrode insertion completion signal, a center electrode insertion error signal is reported in the same manner as in the case where the center electrode is insufficiently inserted (see FIG. 11D). On the other hand, when the center electrode is longer than the specified length l (l ″> l), the transmission-type photoelectric sensor 32 detects the front end of the sensor pin 13b in the insertion direction, and when the total length of the center electrode is normal (l). In other words, the center electrode insertion completion signal is issued in the same manner as described above, that is, when the entire length of the center electrode is excessive, turning cannot be distinguished from the case where the full length is normal, and the cutting tool is started as shown in FIG. In some cases, a defective product may be generated by turning other than the above.

As described above, in the conventional example, even if the center electrode is excessively inserted, it is erroneously determined that the insertion is normal even if the center electrode is excessively long. You. Then, the automatic turning is performed also on the center electrode which is erroneously determined to be normal, resulting in occurrence of defective products. Here, the time required for one cycle of the automatic turning process for the center electrode (insertion of the center electrode → gripping → processing → discharge) is within 10 seconds (usually about 2 to 5 seconds), and this time loss is a factor impeding productivity. It cannot be ignored. In addition, it was discovered that the device was defective at the time of the subsequent assembling process or the subsequent inspection process, and the waste in the manufacturing process was large.

An object of the present invention is to provide an apparatus for manufacturing a center electrode for a spark plug and a method for manufacturing a center electrode for a spark plug, which can suppress the occurrence of defective products at the insertion stage before turning the center electrode. To provide.

[0008]

Means for Solving the Problems and Action / Effect In order to solve the above-mentioned problems, an apparatus for manufacturing a center electrode for a spark plug according to the present invention is provided so that the center electrode can be turned so that the center electrode can be turned. Holding the center electrode inserted in the direction,
A rotary gripper rotatable with the center electrode; a slide member slidable with the insertion of the center electrode; and a biasing force for the slide member in a direction opposite to a slide direction with the insertion of the center electrode. And a position detecting means for detecting whether or not the sliding amount of the sliding member accompanying the insertion of the center electrode is appropriate.

In order to solve the above-mentioned problems, a method of manufacturing a center electrode for a spark plug according to the present invention is characterized in that the center electrode slides along with the axial insertion thereof,
A step of detecting whether or not the slide amount of the slide member urged in the opposite direction to the slide direction by the position detecting means; and detecting that the slide amount of the slide member is the predetermined amount, And performing a turning process by gripping the electrode.

According to the apparatus of the present invention or the method of the present invention,
By detecting the suitability of the sliding amount of the slide member accompanying the insertion of the center electrode by the position detecting means, it is possible to detect the suitability of the gripping position of the center electrode at the insertion stage before turning the center electrode. Therefore, it is possible to suppress the occurrence of defective products not only in the case where the center electrode is too small and the length of the center electrode is too small, but also in the case where the center electrode is too large and the center electrode is too long.

Further, in the present invention, a biasing means for biasing the slide member in a direction opposite to the slide direction accompanying the insertion of the center electrode is provided at the front end side of the slide member in the insertion direction of the center electrode. When the insertion force of the electrode is large and the insertion state becomes excessive, the biasing means has a returning action of returning the center electrode to a normal insertion state. Therefore, even if the position detecting means of the slide member temporarily detects the state of excessive insertion of the center electrode, if the urging means returns the state of insertion of the center electrode to the normal state, the position detecting means of the slide member can be detected. It becomes possible to immediately issue the insertion completion signal of the center electrode. Therefore, even when the insertion force of the center electrode is large and the insertion is temporarily excessive, the turning process is performed on the center electrode in the same way as when the insertion is normal, so that defective products are not wasted. You may live. Also, the biasing means has a buffering action against the insertion of the center electrode, and even if there is a large or small variation in the insertion force of the center electrode, the swing of the slide member accompanying the insertion quickly converges by this buffering action, The position of the slide member can be quickly and accurately detected by the position detecting means.

Further, the position detecting means of the present invention has an adjusting portion for adjusting the relative position in the sliding direction with respect to the slide member, so that the gripping position of the center electrode can be easily and easily determined before the automatic turning of the center electrode is started. Can be determined accurately.

Further, the present invention can have a pushing member for pressing the center electrode in the axial direction, and smoothly press the center electrode in the insertion direction to allow the center electrode inside the center hole of a spindle or the like having a rotary grip portion. Insufficient insertion dimensions of the center electrode due to hooking of the center electrode can be prevented.

Further, a supporting portion for supporting the center electrode when the center electrode is pressed by the pressing member can be provided between the pushing member and the rotary holding portion of the present invention, and the axis of the center electrode can be inserted in the insertion direction. , And can be pushed smoothly.

Further, the slide member of the present invention has a through hole penetrated in a direction intersecting the sliding direction, and the position detecting means is a transmission type photoelectric sensor for detecting whether the slide amount is appropriate via the through hole. Thus, highly accurate positioning control can be performed using a compact and inexpensive position detection sensor.

Further, according to the present invention, the guide member accommodating the slide member slidably has a detection hole, and when at least a part of the detection hole overlaps the through hole, the light emitted from the transmission type photoelectric sensor is provided. Is allowed, stable positioning control can be performed with little influence from external light or the like.

[0017]

Embodiments of the present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is an overall plan view of an apparatus for manufacturing a center electrode for a spark plug according to an embodiment of the present invention. In this manufacturing apparatus, a headstock A and a carriage B are mounted on a bed of a lathe (not shown). Headstock A
Has at least the following components. That is, a spindle 1 (rotating gripper) that rotatably grips the workpiece W of the center electrode by inserting the workpiece W in the axial direction thereof, a power transmission unit 2 for rotating the spindle 1, and an arm (not shown) on the headstock A. And a sensor unit 3 for determining whether the gripping position with respect to the front end face in the insertion direction of the workpiece W is appropriate.
(Position detecting means).

The carriage B has at least a cutting tool 101.
Is provided. On the other hand, a push pin 4 (push member) which is on the rear side in the insertion direction of the work W (hereinafter, also simply referred to as the insertion direction), contacts the rear end face of the work W in the insertion direction, and presses the work W in the insertion direction. , Work W
A support portion 5 is provided between the push pin 4 and the spindle 1 for supporting the work W when the is pressed by the push pin 4.

FIG. 3 is a sectional view of the spindle. The spindle 1 (rotating gripping part) includes a chuck mechanism 12 that inserts and grips a workpiece W serving as a center electrode in the axial direction thereof into a substantially cylindrical spindle body 11 having a center hole 14 penetrating in the axial direction. And an interlocking mechanism 13 (interlocking member) that can move in conjunction with the insertion direction of the workpiece W in accordance with the insertion of the workpiece W. The axial direction of the center hole 14 and the axial direction of the workpiece W, that is, the insertion direction are matched or substantially matched (see FIG. 1). The spindle main body 11 has a substantially stepped cylindrical main body case 11a in which both ends are open and the outer diameter of one end into which the workpiece W is inserted is slightly larger than the other parts. It has an opening lid 11c which is screwed between the opening inner surface of the end portion.

A chuck mechanism 12 is provided in the opening on the large diameter side of the main body case 11a. Three chuck claws 12a urged so as to be movable in the radial direction with respect to the axis of the work W and spread outward in the radial direction are provided at equal intervals in the circumferential direction, and these chuck claws 12a are closed at once. To grip the work W. One end of the opening / closing arm 12b is rotatably supported by a main body block 11d fixed to the main body case 11a by a support shaft 12c. Arm opening / closing spring 1 provided at an intermediate portion in the longitudinal direction of opening / closing arm 12b
2d urges the other end of the opening / closing arm 12b in the opening direction. The slide cylinder 12e is slidable in the axial direction of the workpiece W along the inner wall surface of the large diameter portion of the main body case 11a, and the inner diameter of the opening at the tip end of the slide arm 12e increases toward the opposite side of the workpiece insertion direction. Slope 12f
Is provided. And the inclined part 12f is provided with the opening / closing arm 1
The opening / closing arm 12b and the chuck claw 12a are fitted to the other end of the second arm 2b from the outside, and are pressed from the outside in the radial direction toward the center. Two opening / closing arms 12b are provided corresponding to the respective chuck claws 12a (FIG. 2).
(A)).

The slide mechanism of the slide arm 12e is realized as follows. An arm receiver 12i is provided on the peripheral surface of the middle part in the longitudinal direction of the main body case 11a. The elongated hole 11b is opened along the axial direction, and the other end of the swing arm 12k rotatable around one end is engaged. Thrust bearing 1
2j is slidably fitted into the elongated hole 11b. A spring receiving cylinder 12g, which has a substantially cylindrical shape and houses an interlocking mechanism 13 (interlocking member) described later, includes a main body case 11a.
Are slidably provided in the axial direction of the workpiece W along the inner wall surface of the small diameter portion. The arm receiver 12i has a long hole 11b.
Is screwed onto the outer peripheral surface of the spring receiving cylinder 12g.

The end of the spring receiving cylinder 12g on the workpiece insertion side is screwed with the above-described slide cylinder 12e, and the other end of the spring receiving cylinder 12g has a chuck opening / closing spring 12h arranged inside the small diameter portion of the main body case 11a. Has received one end. The other end of the chuck opening / closing spring 12h is received by the end face of the opening lid 11c facing the inner wall surface of the small diameter portion of the main body case 11a. The chuck opening / closing spring 12h is a compression spring and always closes the chuck claw 12a, that is, the spring receiving cylinder 12h.
g is urged in the direction opposite to the direction in which the workpiece W is inserted.
Instead of the swing arm 12k, a reciprocating arm that can reciprocate in the direction of the axis of the workpiece W may be used, and known driving means such as a hydraulic pressure, a pneumatic pressure, and an electric motor can be used.

When the work W is inserted, the displacement of the work accompanying the insertion in the axial direction is transmitted to the sensor unit 3 to determine whether the gripping position with respect to the front end face in the insertion direction of the work is appropriate. An interlocking mechanism 13 (interlocking member) is provided in order to reliably and efficiently discharge the work to the outside of the spindle 1 at the time of discharging. A first interlocking pin 13a (discharge pin) having an axis center that coincides with or substantially coincides with the axis of the work W is provided in the center hole 14 of the spindle 1, and the front end face in the work insertion direction is inserted into the work of the first interlock pin 13a. In contact with the rear end face in the direction. Also,
A second interlocking pin 13b (sensor pin) having an axis coincident with or substantially coincident with the axis of the first interlocking pin 13a is also provided in the center hole. One end of the second interlocking pin 13b faces the front end of the first interlocking pin 13a in the work insertion direction, and the other end of the second interlocking pin 13a has a communication hole 11 formed in the opening lid 11c.
e, the slider 31 provided on the sensor section 3 is in contact with the rear end face in the workpiece insertion direction.

First and second interlocking pins 1 facing each other
A discharge spring 13c is interposed between 3a and 13b, and both the interlocking pins 13a and 13b and the discharge spring 13c are arranged inside the interlocking pin housing cylinder 14a so as to be slidable in the work axis direction. The interlocking pin housing cylinder 14a has an elongated cylindrical shape comparable to the substantially entire length of the spindle 1 and has an axis coincident with or substantially coincident with the axis of the center hole 14, and an end of the workpiece insertion side is a main body block. 11d is screwed.

The discharge spring 13c provided between the opposing portions of the interlocking pins 13a and 13b is a compression spring and operates as follows. When the work is inserted, the work is moved by the first interlocking pin 13 due to the pushing force of the pushing pin 4 (see FIG. 1).
a to compress the discharge spring 13c and come into contact with the second interlocking pin 13b. From this point, both interlocking pins 13
The a and 13b (and the discharge spring 13c) move integrally in the work insertion direction, and the front end of the second interlocking pin 13b in the work insertion direction presses the rear end of the slider 31 in the work insertion direction. While the pushing force of the pushing pin 4 is applied, the slider 31 is slid in the workpiece insertion direction against the return spring force of the return spring 31e. When an insertion completion signal is issued from the sensor unit 3, the pushing force of the pushing pin 4 is released, the chuck claws 12a are closed, and the work is gripped.

At the time of discharge of the work, when the chuck claw 12a is opened, the slider 31 and the interlocking mechanism 13 are pushed out in the direction opposite to the work insertion direction by the action of the return spring force of the return spring 31e, and the extension of the discharge spring 13c. In addition, the first interlocking pin 13a vigorously discharges the work W from the opening end.

As shown in FIG. 1, the shaft 2 of the electric motor 21
Motor pulley 21b fixed to main body case 1
V-belt 23 between main shaft pulley 22 screwed to 1a
To form the power transmission unit 2. Referring to FIG. 3 again, the spindle 1 is supported inside the main shaft casing 1A via the bearing 1a, and is relatively rotated by the power transmission unit 2 with respect to the main shaft casing 1A. The internal space of the main shaft casing 1A is filled with a lubricating oil having a lubricating action on the bearing 1a and a heat radiating action of heat generated by the rotation of the spindle 1. Oil seals are provided at both ends of the spindle 1 adjacent to the bearing 1a. 1b is provided.

FIG. 4 shows the details of the sensor section (position detecting means). The sensor unit 3 includes a slider 31 (sliding member) slidable in the axial direction of the workpiece W, a transmission-type photoelectric sensor 32 (position detecting means) for detecting a position of the slider 31 in the sliding direction, and a An adjuster 33 (adjustment unit) for fixing the transmission type photoelectric sensor 32 so as to be movable in the sliding direction and to be able to hold an arbitrary position.

A return spring 31e (biasing means) for biasing the slider 31 in the direction opposite to the insertion direction is provided at the front end side of the slider 31 in the workpiece insertion direction. Slider 3
1 and the return spring 31e are accommodated in a guide member composed of a guide block 31b located below and on the side thereof and an upper wall block 31b 'located above these, so that the slider 31 It is slidable along these guide members. The front and rear ends of the guide member in the insertion direction are the second interlocking pins (sensor pins) 13b of the interlocking mechanism 13.
Is covered with a front wall block 31c having an entrance through which the front end of the insertion hole passes, and a rear wall block 31d receiving one end of a return spring 31e on its inner wall surface.

In a transmission type photoelectric sensor 32 as a slide member position detecting means, a light emitting device 32a and a light receiving device 32b having an optical axis substantially perpendicular to a workpiece insertion direction are fixed to opposing side walls of a guide block 31b. Provided.
At this time, the slider 31 is provided with a through hole 31a having an axis substantially coinciding with the optical axis, while penetrating the opposing side wall of the guide block 31b and having a detection hole 32c having an axis substantially coincident with the axis of the through hole 31a. Is provided. Through hole 3
When the detection hole 32c overlaps the detection hole 32a, the light emitted from the light emitter 32a of the transmission type photoelectric sensor 32 passes through the through hole 3c.
It passes through 1a and the detection hole 32c and reaches the light receiver 32b. In this manner, the light receiver 32 of the transmission photoelectric sensor 32
When b detects the transmitted light, a work insertion completion signal is issued, and the chuck mechanism 12 of the spindle 1 rotatably holds the rear end of the work in the insertion direction. Then, spindle 1
Turning is performed on a portion of the work projecting rearward in the insertion direction.

Here, the diameter of the through hole 31a and the detection hole 32c
Does not need to be the same diameter, and it is not necessary to set so that the insertion completion signal is issued only when both are completely coincident, or only when one completely encloses the other. . That is, when at least a part of the through hole 31a and the detection hole 32c overlap, the light emitted from the light emitting device 32a passes through and reaches the light receiving device 32b,
It is only necessary that the light receiver 32b can detect this transmitted light. In addition,
The detection hole 32c does not penetrate the opposing side wall of the guide block 31b, and the light emitting device 32a and / or the light receiving device 32b
The guide block 31b may be provided in a buried manner on the opposing side wall.

If the transmission type photoelectric sensor and the through hole of the slide member are used as the slide member position detecting means as in this embodiment, a compact and inexpensive manufacturing apparatus can be obtained. In addition, as the position detecting means of the slide member,
A known non-contact type sensor such as a reflection type photoelectric sensor or an ultrasonic sensor and the surface of a slide member, a proximity sensor or a distance between a magnetic scale and a slide member can be widely applied. Also,
As the urging means, an air cushion type cylinder or the like can be used instead of the return spring.

FIG. 4 shows the adjuster 33 (adjustment section).
As shown in FIG. 7, adjustment screws 33a are provided and screwed to the adjustment shaft 33b and the lower part of the guide block 31b, respectively. Adjustment knob 33 formed integrally with adjustment shaft 33b
When b ′ is rotated, the guide block 31b to which the transmission type photoelectric sensor 32 is fixed moves the slider 3 on the base 33c.
1 in the sliding direction. 33d is a fixing bolt for fixing the guide block 31b to the base 33c at an arbitrary position, and 33e is a washer inserted through the adjustment shaft 33b.

It is convenient to use the adjuster 33 in the following case. That is, when machining the first work or when switching to a work of a different model number (so-called setup change), first, prior to the start of automatic turning of the work, a work of a predetermined model number is artificially optimized under optimal conditions. Perform turning. Next, with the processed work held, the adjustment knob 33b 'is rotated to move the transmission photoelectric sensor 32 in the sliding direction of the slider 31. Then, when the through hole 31a and the detection hole 32c overlap, a work insertion completion signal is issued. If the fixing bolt 33d is tightened in this state, the first and optimal gripping position in the axial direction is determined for the work of the predetermined model number, and thereafter, automatic turning is performed while following the gripping position and controlling. Just do it. The insertion dimension of the work may be automatically measured and stored on the device side or artificially measured and input.

Referring to FIG. 3 while referring to FIG. 1, a push pin 4 (a push member) and a support plate 5 (a support portion) which are used to assist in inserting the workpiece W of the center electrode into the chuck mechanism 12 will be described. I do. The push pin 4 is located on the rear side in the work insertion direction, and its front end face in the work insertion direction contacts the rear end face in the work insertion direction to press the work in the insertion direction. After the workpiece is gripped by the chuck mechanism, the workpiece is retracted to a position where the processing and discharge of the workpiece are not hindered. The pushing force F is larger than the return spring force F ′ of the return spring 31e and the compression spring force f of the discharge spring 13c described above. Therefore, in particular, the distal end portion of the push pin 4 is required to have a small diameter and to have strength and durability.

A support plate 5 that supports the work W when the work W is pressed by the push pin 4 is provided between the push pin 4 and the spindle 1. The support plate 5 serves to support the work so that the insertion direction does not deviate from the axial direction when the work is inserted, and to prevent the insertion dimension from being excessively increased due to the strong pushing force F being applied to the inserted work. It has a resistance imparting action of imparting a light resistance, and functions as an auxiliary chuck claw.

As shown in FIG. 2A, in this embodiment, the support plate 5 is a pair of rectangular or rectangular resistance plates 5a, 5a.
And one side in the longitudinal direction thereof is brought into contact with each other, and the contact surface is provided along the radial direction of the spindle 1. The contact surface has a first contact surface 5a1 near the center of the spindle, and a second contact surface 5a2 in a form in which the first contact surface 5a1 is in contact with each other to form a gap in the radial direction of the spindle 1. And both contact surfaces 5a1, 5a
The boundary of 2 is the rotation fulcrum 5a3. Rotating fulcrum 5a
An opening / closing spring 5b is stretched between the ends of the two resistance plates 5a, 5a on the outer diameter side than 3. The opening / closing spring 5b is a compression spring that urges the center-side ends of the resistance plates 5a, 5a in a normally closed direction. Work insertion holes 5c, 5c including the axis of the spindle 1 are provided in both resistance plates 5a, 5a in half.

When the push pin 4 contacts the rear end face of the work W in the insertion direction and presses the work W with the chuck claw 12a opened, the work W is inserted into the work insertion hole 5c with both resistance plates 5a, 5a closed. , 5c while being supported while receiving resistance, and inserted into the chuck mechanism 12 (FIG. 2A). When the support plate 5 is pulled up in the direction of the arrow in FIG. 2B while the chuck claws 12a are closed and the work W is held, the work W
The outer peripheral surfaces of the two resistance plates 5a, 5a are pushed open between the ends on the center side against the tightening spring force of the opening / closing spring 5b, and the support plate 5 can be retracted to a predetermined position. In some cases, a plurality of support plates 5 (resistance plates 5a, 5a) having different hole diameters of the work insertion holes 5c, 5c according to the outer shape of the work W may be prepared.

The operation state of the spindle shown in FIG. 3 is shown in FIGS.
Shown in FIG. 5 shows the inserted state of the center electrode, FIG. 6 shows the held state of the center electrode, and FIG. 7 shows the discharged state of the center electrode.

In order to set the work W from the standby state shown in FIG. 3, it is necessary to first open the chuck mechanism 12 and insert the work W as shown in FIG. Then, the swing arm 12k is turned to rotate the arm receiver 1k.
When the workpiece 2i is moved in the workpiece insertion direction (rightward in FIG. 5), the spring receiving cylinder 12g and the slide cylinder 12e integrally slide to the right against the urging force of the chuck opening / closing spring 12h. The opening / closing arm 12b is an arm opening / closing spring 12
With the spring force of d, it opens radially outward, and the chuck pawl 12a similarly opens radially outward. When the push pin 4 presses the work W held by the work insertion hole sealing surfaces 5c, 5c of the support plate 5, the movement of the work is transmitted to the first interlocking pin 13a by the pushing force of the push pin 4, and the discharge spring is moved. 13c is compressed and comes into contact with the second interlocking pin 13b. From this point, the two interlocking pins 13a and 13b (and the discharge spring 13c) move integrally in the work insertion direction, and move to the second interlocking pin 13b.
The front end of the slider 31 in the work insertion direction presses the rear end of the slider 31 in the work insertion direction. While the pushing force of the pushing pin 4 is acting, the slider 3 is pressed against the return spring force of the return spring 31e.
Slide 1 in the workpiece insertion direction.

Next, as shown in FIG.
Is set to “closed”, and the operation proceeds to an operation of gripping the work W. For this reason, when the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b overlap, and the insertion completion signal is issued from the sensor unit 3, the pushing force of the pushing pin 4 is released. At the same time, when the swing arm 12k is rotated to move the arm receiver 12i in a direction opposite to the workpiece insertion direction (leftward in FIG. 6), the spring receiving cylinder 12g and the slide cylinder 12e are moved by the urging force of the chuck opening / closing spring 12h. Slide together to the left. The opening / closing arm 12b closes radially inward against the spring force of the arm opening / closing spring 12d,
Similarly, the chuck claw 12a is also closed radially inward to
Is gripped. In this state, the support plate 5 is retracted to a predetermined position, and the work W is subjected to turning by the cutting tool 101.

FIG. 7 shows an operation of discharging the workpiece W after the turning. As in FIG. 5, when the swing arm 12k is rotated to move the arm receiver 12i in the workpiece insertion direction (rightward in FIG. 7), the chuck pawl 12a is opened again. Then, the slider 31 and the interlocking mechanism 13 are pushed out in the direction opposite to the work insertion direction by the action of the return spring force of the return spring 31e, and the discharge spring 13c is further extended, so that the first interlocking pin 13a opens the work W vigorously. Discharge from the edge.

FIG. 8 shows a slider using a transmission type photoelectric sensor.
3 schematically shows the situation of position detection. Performs automatic turning
To do this, at the stage of inserting the work,₀
Whether the workpiece can be gripped correctly at the position
It is an object of the present invention to detect the
It is. However, actually, the specified gripping dimension x₀Measure
No need to detect. Insert a workpiece with a total length of l for dimension L
Then, the specified gripping dimension x ₀Together with the workpiece in the insertion direction
Position of the end face, and thus the front end of the sensor pin 13b in the insertion direction
Position of the surface, and furthermore, the position of the through hole 31a of the slider 31
Are determined one after another. After all, the transmission type photoelectric sensor
32, the through hole 31a of the slider 31 and the guide block 3
What is necessary is to detect the overlap with the detection hole 32c of 1b.
Become. Then, the appropriate position of the gripping position of the work W to be detected is determined.
No is detected by replacing the slide amount of the slider 31 with appropriateness.
Or it can be determined.

When the insertion dimension L of the workpiece is normal and the overall length l of the workpiece is normal (FIG. 8A), the center electrode W of the overall length 1 is inserted into the tool post with respect to the center hole 14 passing through the center of the spindle 1. Push pin 4 from 10 side
Insertion dimension (push dimension) due to the pushing force
When only L is inserted, the movement of the work is transmitted to the first interlocking pin 13a inside the center hole 14, and the discharge spring 1
3c is compressed and comes into contact with the second interlocking pin 13b.
From this point, the interlocking pins 13a and 13b (and the discharge spring 13c) move integrally in the work insertion direction, and the front end of the second interlocking pin 13b in the work insertion direction is the slider 31.
Of the work insertion direction. While the pushing force of the pushing pin 4 is applied, the slider 31 is slid in the workpiece insertion direction against the return spring force of the return spring 31e.
If the work insertion dimension L is normal and the work total length l is normal, the slide amount of the slider 31 reaches the specified amount.
The transmission type photoelectric sensor 32 having the light emitting device 32a and the light receiving device 32b is provided with the through hole 31a of the slider 31 and the guide block 3
An overlap with the detection hole 32c of 1b is detected, and an insertion completion signal is issued. Based on the insertion completion signal, the chuck mechanism 12 of the spindle 1 rotatably holds the work, and performs a turning process on a portion of the work protruding rearward in the insertion direction from the chuck mechanism 12.

In the case where the insertion dimension of the work is insufficient (L '<L) (FIG. 8B) If the insertion dimension of the work is insufficient due to, for example, hooking of the work inside the center hole 14, the slide amount of the slider 31 is reduced. The specified amount is not reached. In this case, the transmission type photoelectric sensor 32 cannot detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b, and generates an insertion error signal instead of the insertion completion signal.

When the insertion dimension is temporarily excessive (L "> L) (FIGS. 8C and 8C ') When the insertion dimension is temporarily excessive, for example, when the pushing force F is too large. In this case, α, β, and γ are provided between the push pin 4 and the workpiece W, between the workpiece W and the first linkage pin 13a, and between the first linkage pin 13a and the second linkage pin 13b, respectively. In this state, since the sliding amount of the slider 31 is larger than the specified amount, the transmission type photoelectric sensor 32 has the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b. Cannot be detected, and an insertion error signal is generated, but the pressing force F of the pressing pin 4
Does not work, and the return spring force F ′ of the return spring 31e
(Larger than the compression spring force of the discharge spring 13c).
When the state returns to the state in FIG. 8C similar to that of FIG. 8A, the sliding amount of the slider 31 also returns to the specified amount. Then, an insertion completion signal is issued and the workpiece is turned. As described above, also in this case, the insertion error signal is temporarily generated. However, this is a problem of the position detection timing and can be solved. That is, as described above, if the detection of the position of the slider 31 by the transmission type photoelectric sensor 32 is delayed or the detection is continued for a time during which the return spring 31e exerts the buffering action and the returning action with respect to the insertion of the workpiece, the insertion error is reduced. No signal is emitted.

When the total length of the work is too small (l '<l) (FIG. 8 (d)) Next, when a product having a different model number is mixed and a work shorter than the specified length is inserted, the work insertion dimension is set. Is normal (L), the sliding amount of the slider 31 does not reach the specified amount. In this case, the transmission-type photoelectric sensor 32 includes the through hole 31a of the slider 31 and the detection hole 3 of the guide block 31b.
2c cannot be detected, and an insertion error signal is issued.

When the total length of the work is excessive (l ″> l) (FIG. 8E) Further, when a work longer than the specified length is inserted,
If the workpiece insertion dimension is normal (L), the slider 31
Is larger than the specified amount. Also in this case, the transmissive photoelectric sensor 32 cannot detect the overlap between the through hole 31a of the slider 31 and the detection hole 32c of the guide block 31b, and an insertion error signal is generated.

FIG. 9 shows a flowchart of a method for manufacturing a center electrode for a spark plug according to the present invention. In FIG. 9, before entering the automatic turning process, it is checked whether or not the grip position determination switch is ON (S1). At the beginning of the work or at the time of setup change, the gripping position of the work is artificially determined by the gripping position determination program (S2 and FIG. 10). Next, the model number of the work, the total length l of the work, and the insertion dimension L are read in the program or input manually (S
3). Subsequently, in order to execute the automatic turning, the start switch, the stop switch, and the supply of the work are checked (S4, S5, S6).

From here, automatic turning is performed. The chuck pawl 12a is set to "open", and the work is pushed by the pushing pin 4 by the insertion dimension L (S7, S8 and FIG. 5). The delay in detecting the position of the slider 31 by the transmission type photoelectric sensor 32 is delayed only for the time when the return spring 31e exhibits the buffering action and the return action with respect to the insertion of the work. Photodetector 32b of the photoelectric sensor 32
It is checked whether or not has received transmitted light (S10). If the light receiver 32b remains OFF, the work insertion dimension is insufficient (L '<L) (FIG. 8B), and the work total length is too small (1'<1) (FIG. 8D). ) Or the case where the overall length of the work is excessive (l ″> l) (FIG. 8E), an insertion error signal is issued (S11), while the transmission type photoelectric sensor 32 penetrates the slider 31. Hole 31
a and the detection hole 32c of the guide block 31b are detected, and when the light receiver 32b is turned on, an insertion completion signal is transmitted (S12), and the chuck jaws are closed to grip the workpiece (S13 and S13). (Fig. 6). The turning is performed by rotating the spindle (S14), and after the processing, the work is discharged with the chuck jaws opened (S15 and FIG. 7).

Again, the light receiver 32b of the transmission photoelectric sensor 32
It is checked whether or not no longer receives the transmitted light (S1).
6) If the light receiver 32b remains ON, it is determined that the work is clogged and an insertion error signal is issued (S1).
1). Finally, it is checked again whether or not the grip position determination switch is ON (S17). If the setup is to be changed, the program proceeds to the grip position determination program (S2). If the automatic turning is continued, the process proceeds to the preparation check step (S4). Return. In addition,
The time required for one cycle of the flowchart of FIG. 9 is within 10 seconds (about several seconds).

FIG. 10 shows a flowchart for determining a gripping position which is a part of FIG. When processing the first work or switching to a work of a different model number (so-called setup change), the gripping position determination program (S2) is executed before the start of the automatic turning of the work. After the automatic turning is stopped (S21), a work of a predetermined model number is set to close the chuck jaws (S22), and the turning is artificially performed under optimal conditions (S23). Next, while holding the processed workpiece, the adjustment knob 33b 'is turned,
When the transmission photoelectric sensor 32 is moved in the sliding direction of the slider 31, when the through hole 31a and the detection hole 32c overlap, a work completion signal is issued (S2).
4). If the fixing bolt 33d is tightened in this state, the first and optimal gripping position in the axial direction of the work of the predetermined model number is determined (S25). Thereafter, the automatic turning is performed while following the gripping position. The insertion dimension of the work may be automatically measured and stored on the device side or artificially measured and input.

[Brief description of the drawings]

FIG. 1 is an overall plan view of an apparatus for manufacturing a center electrode for a spark plug according to an embodiment of the present invention.

FIG. 2 is a side view taken along the line XX of FIG. 1;

FIG. 3 is a longitudinal sectional view of a spindle.

FIG. 4 is a detailed view of a sensor unit.

FIG. 5 is a longitudinal sectional view of the spindle of FIG. 3 showing a state in which a center electrode is inserted.

FIG. 6 is a longitudinal sectional view of the spindle of FIG. 3 showing a state of holding the center electrode.

FIG. 7 is a longitudinal sectional view of the spindle of FIG. 3 showing a state in which a center electrode is discharged.

FIG. 8 is a schematic diagram showing position detection of a slider by a transmission type photoelectric sensor.

FIG. 9 is a flowchart showing a method for manufacturing a center electrode for a spark plug according to the present invention.

FIG. 10 is a flowchart for determining a gripping position that forms part of FIG. 9;

FIG. 11 is a schematic view corresponding to FIG. 8, showing conventional position detection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle (rotation holding part) 4 Push pin (push member) 5 Support plate (support part) 13 Interlock mechanism (interlock member) 31 Slider (slide member) 31a Through hole 31b Guide block (guide member) 31b 'Upper wall block ( Guide member) 31e return spring (biasing means) 32 transmission type photoelectric sensor (position detection means) 32c detection hole 33 adjuster (adjustment part) W work (center electrode)

Claims (7)

[Claims] 1. A center electrode inserted in an axial direction is gripped so that a turning process can be performed on the center electrode, and
A rotary gripper rotatable with the center electrode; a slide member slidable with the insertion of the center electrode; and a biasing member for urging the slide member in a direction opposite to a sliding direction with the insertion of the center electrode. A device for manufacturing a center electrode for a spark plug, comprising: a biasing means; and a position detecting means for detecting whether or not a slide amount of a slide member accompanying the insertion of the center electrode is appropriate. 2. The apparatus for manufacturing a center electrode for a spark plug according to claim 1, wherein said position detecting means has an adjusting section for adjusting a relative position in said sliding direction with respect to said slide member. 3. The apparatus for manufacturing a center electrode for a spark plug according to claim 1, further comprising a pressing member for pressing the center electrode in the axial direction. 4. The spark plug according to claim 3, further comprising a supporting portion between said pushing member and said rotary grip portion, said supporting portion supporting said center electrode when said pushing force is applied to said center electrode. Central electrode manufacturing equipment. 5. The transmission type photoelectric conversion device according to claim 1, wherein the slide member has a through hole penetrating in a direction intersecting the slide direction, and the position detecting means detects whether the slide amount is appropriate via the through hole. The apparatus for manufacturing a center electrode for a spark plug according to any one of claims 1 to 4, which is a sensor. 6. A guide member which slidably accommodates the slide member has a detection hole, and is emitted from the transmission type photoelectric sensor when at least a part of the detection hole overlaps with the through hole. The apparatus for manufacturing a center electrode for a spark plug according to claim 5, wherein light is allowed to pass therethrough. 7. A step of sliding along with the insertion of the center electrode in the axial direction, and detecting by a position detecting means whether or not the sliding amount of the sliding member urged in the direction opposite to the sliding direction is appropriate. A step of gripping and turning the center electrode when it is detected that the slide amount of the slide member is a predetermined amount.