JPH06286020A - Apparatus for formation of bead core - Google Patents

Abstract

PURPOSE:To produce bead cores in a variety of kinds in different inner diameters easily by employing a single winding former, and to improve accuracy in dimensions for those inner diameters. CONSTITUTION:In a bead core-forming apparatus with a winding former 2 equipped with a dented groove 4 provided to a pivoted rotating body 3, the pivoted rotating body 3 is equipped with a rotating cylinder 5 and an inner shaft 7 that is loose-fitted into the rotating cylinder 5 and turns together with the rotating cylinder while moving relatively to the rotating cylinder in forward and rearward directions. The winding former 2 is formed of segments 27 in sector forms divided round the axial center, and the divided segments 27 are arranged either to the rotating cylinder 5 or the inner shaft 7 so that they can slide in the diametral direction within the plane that is at right angle to the axial center while the divided segments 27 are connected with a link 10 either to the rotating cylinder 5 or the other end of the inner shaft. A stopper 11 for adjusting the amount of relative movement is provided to the pivoted rotating body 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead core forming apparatus capable of easily forming a plurality of types of bead cores having different inner diameters by using a single winding former and also improving the dimensional accuracy of the inner diameter.

[0002]

2. Description of the Related Art In a pneumatic tire T, for example, as shown in FIG. 9, an annular bead core C for locking a folded portion of a carcass b to a bead portion a mounted on a rim and maintaining tire rigidity. This bead core C is normally formed by spirally winding a rubberized steel bead wire W on a former f as shown in FIG.

Further, such a former f is conventionally shown in FIG.
As shown in FIG. 2, the pair of formers f1 and f2 in a disk shape is divided into right and left along the groove m for winding the bead wire, and the formers f1 and f2 are concentrically arranged with a gap g. The bead core C completed by making the former f2 slidable along the axis while pivotally supporting each using the above-mentioned supporting shafts h1 and h2.
It was removable from.

[0004]

However, in the conventional former, since the outer diameter of the concave groove is constant, in order to form a plurality of types of bead cores having different inner diameter dimensions,
The number of types of formers has increased, such as the need to prepare a former according to each inner diameter, which impairs the management and storability of the formers, and it takes time and labor to replace the formers for each lot, resulting in a significant increase in production efficiency. descend.

The present invention is based on the fact that the outer peripheral surface of the former is formed to be expandable and contractable and the amount of expansion is adjusted by a stopper, and a bead core having various inner diameters can be formed by using one former. The present invention relates to a bead core forming device capable of solving the above problems.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a bead wire is wound around a grooved former of a winding former having a groove formed on an outer peripheral surface thereof and arranged on a rotatable shaft while being supported by a frame. A bead core forming device for forming a bead core of a tire, wherein the support shaft has a rotary cylinder having an inner hole concentric with the axis of the support shaft, and the shaft is loosely inserted into the inner hole. The winding former has a sector shape and an outer peripheral surface divided about the shaft center, the center shaft being capable of moving forward and backward relative to the rotating cylinder in the axial direction and being integrally rotatably locked to the rotation cylinder. It is composed of a plurality of divided segments provided with the above-mentioned concave groove, and these divided segments are immovable in the axial direction in one of the rotary cylinder or the center shaft and slidable in the radial direction in a plane perpendicular to the axial center. In addition, one end of the link body is pivotally attached to each of the divided segments and the other end of the link body is pivotally supported on the other of the rotary cylinder or the center shaft, so that the relative advance / retreat movement causes the radial movement through the link body. In addition, the bead core forming device is provided with a stopper capable of adjusting the relative movement amount on the support shaft body.

[0007]

The winding former is formed by the fan-shaped divided segments which are divided around the axis of rotation, and the divided segments are provided on either the center shaft or the rotary cylinder in a plane perpendicular to the axis. It is arranged so as to be slidable in the radial direction, and each segment is connected to either the center shaft or the rotary cylinder via the link body.

Accordingly, the relative movement of the center shaft and the rotary cylinder in the axial direction causes the divided segments to slide in the radial direction by the same distance, so that the outer peripheral surface of the winding former can be expanded / contracted. As a result, the bead core formed at the time of diameter expansion can be easily removed from the former at the time of diameter reduction.

Further, by adjusting the relative movement amount by the stopper, the diameter of the outer peripheral surface of the former at the time of expanding the diameter can be freely changed, and a bead core having various inner diameters can be formed by using one former.

Further, the product error of the inner diameter of the bead core caused by variations in processing of the former, variations in assembly of the device, etc.
By adjusting the relative movement amount by the stopper, correction can be made in the final step, product accuracy can be improved and production efficiency can be improved, and management and storage efficiency of the former can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the figure, a bead core forming apparatus 1 includes a winding former 2 having a groove 4 formed on an outer peripheral surface thereof in which a bead wire W for forming a bead core C of a tire T is spirally wound.
And a rotatably supporting shaft body 3 on which the winding former 2 is arranged. The supporting shaft body 3 is composed of a rotary cylinder 5 and a center shaft 7.

The rotary cylinder 5 has a pair of side plates 15 and 15, for example, the side plates 15 and 1 of a gate-shaped frame 13 in which they are raised.
5, a base cylinder 19 rotatably supported via a bearing piece 16
A holder 20 for holding the former is integrally fixed to one end of the base cylinder 19. The base cylinder 19 has an inner hole 6 that is concentric with the shaft center of the support shaft body 3 that is the center of rotation, and has a large diameter between the bearing pieces 16, 16, for example. So that it cannot slide in the direction
Locked at 3. In the base cylinder 19, the electric motor M attached to the frame 13 has, for example, a pulley 17A and a drive belt 17B.
Are connected via a drive transmission means 17 such as the above, whereby the start and stop of the rotation are repeated every time the bead core C is formed. Further, the base cylinder 19 has one end with one bearing piece 16
The holder 20 is attached to the protruding portion.

The holding body 20 has a base portion 20A integrally fixed to the protruding portion by using a key or the like, and the front end of the body portion extending radially outward and forward from the base portion 20A has the axial center. Flange portion 20B with a brim that faces at a right angle to
Is provided.

The center shaft 7 is in the shape of a round shaft slidably inserted in the inner hole 6 so that it can be moved forward and backward relative to the rotary cylinder 5 and in the axial direction. The base cylinder 19 is provided with an elongated hole 19A extending in the axial direction,
By inserting the locking pin projecting from the center shaft 7 into the elongated hole 19A, the center shaft 7 is locked so as to rotate integrally with the rotary cylinder 5. The locking pin may be eliminated by using a square shaft body as the center shaft 7.

The front end portion and the rear end portion of the center shaft 7 extend beyond the base cylinder 19 in the front-rear direction, and a bracket 21 for holding a link body is fixed to the front end portion, and the rear end portion is also fixed. An advancing / retreating drive tool 22 for urging the central shaft 7 back and forth is connected to the.

The advancing / retreating drive member 22 is composed of the frame 13
An air cylinder 23, which is flanged to a subframe 13A continuous with the rod and has a rod concentric with the axis,
The air cylinder 23 includes a floating joint 24 such as a ball joint attached to the rod end, and a thrust bearing 25 fixed to the joint and attached to the rear end portion of the center shaft 7. Therefore, the advancing / retreating drive tool 22 can move the center shaft 7 in the axial direction through the thrust bearing 25 as the rod of the air cylinder 23 expands and contracts. Further, since the forward / backward drive tool 22 is provided with the joint 24,
Since the center misalignment between the rod and the center shaft 7 is absorbed and the air cylinder 23 and the center shaft 7 are indirectly connected via the thrust bearing 25, the load on the center shaft 7 by the air cylinder 23 can be reduced. Thrust bearing 2
5 is provided with a detent 26 extending radially outward from the housing, and the detent 26 is attached to the sub-frame 1
The thrust bearing 25 is prevented from rotating by engaging with the locking portion 13B protrudingly provided on 3A so as to be slidable in the axial direction.

Further, as shown in FIGS. 1 and 2, the winding former 2 is a donut-shaped disc body having a central hole concentric with the shaft center and having a groove 4 on the outer peripheral surface thereof. It is composed of three to four fan-shaped divided segments 27 ... Which are equally divided into four with the axis as the center. Further, in this example, as shown in FIG. 2, each of the divided segments 27 is arranged on the inner side in the radial direction and is arranged on the inner plate piece 27A held on the flange portion 20B of the rotary cylinder 5 and on the outer side in the radial direction. Plate piece 27
The outer plate piece 27B has a groove 4 formed on the outer peripheral surface and is bolted so as to be replaceable with A.

Further, for example, two rails 29 extending inward in the radial direction are provided on the rear surface of the inner plate piece 27A and in the center thereof. The rails 29 in this example are the flange portions 20B. Guided by a guide 30 provided on the front surface.

The guide 30 has substantially wedge-shaped guide grooves 30A having a tapered cross section, which are recessed in parallel with each other in the radial direction, and the rails 29 are fixedly engaged with the guide grooves 30A. Therefore, each divided segment 27 becomes
It is held so that it cannot move in the axial direction and can slide in the radial direction in a plane perpendicular to the axial center. The flange portion 20
Rail 29 on the B side and guide 3 on the segment 27 side
0 may be formed, and various guide means having a well-known structure may be used as long as the rail and the guide can be fixedly engaged with each other.

Further, in each of the divided segments 27, a link body 1 extending radially outward from the axial center, that is, extending outward in the radial direction, between the rails 29 and 29 on the rear surface of the inner plate piece 27A.
One end of 0 is pivotally mounted, and the other end of the link body 10 is pivotally supported by the front end portion of the center shaft 7 via the bracket 21. Therefore, each of the divided segments 27 is formed by the operation of the air silling 23.
By the relative advancing / retreating movement of the winding body 2, the sliding movement can be performed in the radial direction via the link body 10, and by this sliding movement, the outer peripheral surface of the winding former 2 is expanded / contracted.

A stopper for adjusting the diameter of the outer peripheral surface of the winding former 2 at the time of expanding the diameter of the support shaft body 3 by adjusting the relative movement amount between the center shaft 7 and the rotary cylinder 5. 11 is provided.

In the present example, the stopper 11 is fixed to the front end of the center shaft 7 and a stopper 50 fixed to the rotary cylinder 5 via a mounting member 51, as shown in an enlarged view in FIG. It is provided with a receiving member 52 capable of adjusting a relative movement amount by abutting against the hitting member 50.

In the present embodiment, the hitting tool 50 is screwed into a screw hole 53 at the front end of the center shaft 7 and has a central screw hole 54A concentric with a bolt fitting 54, as shown in FIG.
A damper 55 which is screwed into the central screw hole 54A of the bolt fitting 54 with the front end portion left, and the damper 5
5 is screwed to the front end portion and the bolt fitting 54
And a cap nut 56 for firmly fixing the damper 55 in the shape of a double nut by being pressed against the head of the.

Further, the damper 55 is an oil damper in this example, and the cylinder 55 is provided with a screw portion on the outer peripheral surface for screwing with the bolt fitting 54 and the cap nut 56.
A and a piston portion 57A that divides the inside of the cylinder 55A into a front chamber and a rear chamber by slidingly fitting the cylinder 55A slidably through the front end of the cylinder 55 and extending back and forth at the rear end. The piston part 5 is provided with the lot 57 provided and the oil enclosed in the front chamber and the rear chamber.
7A is formed with a small-diameter flow path that exerts a damper effect by connecting the front chamber and the rear chamber. In this example, for example, the spring piece 59 for returning the rod 57 is housed in the rear chamber.

The receiving member 52 is, in this example, the holding member 2
A bolt fitting which is bolted to the front surface of 0 and extends forward along the axis center between the pair of leg pieces 51A, 51A by a fitting piece 51B. The receiving part 52B that can be brought into contact with the contact surface 56S at the front end of the cap nut 56 at the rear end of the screw shaft part 52A that is detachably attached to the attachment piece 51B.
Is protruding.

The receiving member 52 has a head portion 52C at the front end of the screw shaft portion 52A. Therefore, the relative amount of movement of the center shaft 7 that moves relatively toward the front is regulated by the contact between the contact surface 56S and the receiving portion 52B, whereby the winding former at the time of expanding the diameter. A diameter of 2 is set. The relative movement amount can be freely adjusted by changing the protrusion amount G of the receiving portion 52B from the mounting piece 51B. In this example, a plurality of types of receiving tools 52 having different protrusion amounts G are prepared. The amount of movement can be freely adjusted by selecting and attaching, and the bead cores C having various diameters are formed by using one former.

The change in the protrusion amount G can be performed by, for example, moving the receiving member 52 back and forth, and in such a case, the receiving member 52 has a screw shaft portion 52A as shown in FIG.
Is made long and is fixed to the mounting piece 51B using a double nut. Further, the contact surface 5 is always urged by the urging of the spring piece 59.
The rod 57 of the damper 55 protruding forward beyond 6S comes into contact with the receiving tool 52 prior to the Kip nut 56, so that the impact with the receiving tool 52 can be mitigated.

Further, at least one of the four divided segments 27 is provided with the clamp means 12 for fixing the winding start portion W1 of the bead wire W.

As shown in FIGS. 3, 4, 5 and 6, the clamping means 12 is disposed on the discontinuous portion 31 and the discontinuous portion 31 where the outer peripheral surface of the divided segment 27 is discontinuous. It includes a contact piece 32 and a lever 33.

As shown in FIG. 6, the discontinuity portion 31 has
When the winding starter W1 is supplied to the bead core forming apparatus 1 and the winding former 2 is in a standby / stop state, the winding starter W1 is parallel to the vertical surface S1 from a position on the outer peripheral surface different from the vertical surface S1 passing through the axis of the winding former 2. Moreover, the groove 4 is formed of a substantially rectangular notch having a depth that exceeds the bottom surface 4S of the groove 4 inward in the radial direction.

Therefore, when the bead wire W is supplied parallel to the circumferential direction of the former 2, that is, on the plane parallel to the plane orthogonal to the axis, the interruption 31 is upstream of the supply from the vertical plane S1. By being located on the side, the end edge of the winding start end W1 is located inward of the groove bottom surface 4S in the radial direction and is inserted into the discontinuity portion 31. In this example, in the standby / stopped state, the opening of the interrupted portion 31 is cut out so as to face upward, and therefore the bead wire W is supplied by dropping the winding start end W1 from above into the interrupted portion 31. Done.

Further, the discontinuity 31 is provided with a contact piece 32 and a lever 33 without protruding into the concave groove 4. In this example, the contact piece 32 and the lever 33 are integrally assembled to be portable. Formed as a clamp unit 12A.

That is, the clamp unit 12A includes the contact piece 32, the lever 33, and a case body 35 for supporting them.
Formed from.

The case body 35 has a U-shape in which the front ends of the side plate pieces 35A parallel to each other along the side surfaces 31S and 31S sandwiching the discontinuity 31 are joined by the front plate piece 35B, and the side plate piece 3 is formed.
A mounting piece 35C, which is bolted to the front surface of the winding former 2, projects from the front plate piece 35B at a position reserved rearward from the front plate piece 35B.

The abutting piece 32 is located on the side of one groove wall that sandwiches the concave groove 4, that is, the rear groove wall F1 in this example, and forms a block shape that is bridged between the upper ends of the side plate pieces 35A. . Further, the contact piece 32 has an upper edge e1 that is substantially aligned with the groove bottom edge E1 on the groove wall F1 side in the concave groove bottom surface 4S and has a contact surface 36S that extends in the radial direction at right angles to the axis. Part 3
6, an upper portion 37 having a slope 37S extending radially outward from the upper edge e1 along the groove wall surface on the groove wall F1 side is provided above the lower portion 36.

Further, the lever 33 includes the side plate pieces 35A,
A support shaft 39 perpendicular to the vertical surface S1 held between 35A.
A pivotal support 33A pivotally supported around the support 33B, a gripping part 33B having a gripping surface 33S protruding radially outward from the pivotal support 33A and facing the contact surface 36S, and the pivotal support 33
It has an arm portion 33C which extends from A through the lower side of the abutting piece 36 to the rear. Therefore, the lever 33 is rotated around the support shaft 39 so that the tip of the grip portion 33B is located on the other (front) groove wall F2 side, and the grip surface 33S is separated from the contact surface 36S from the separated state Y1. The tip end is located on the one (rear) groove wall F1 side, and the grip surface 33S can move up to the proximity state Y2 in which the grip surface 33S approaches the contact surface 36S.

The tip of the grip portion 33B is arranged inwardly inward in the radial direction from the bottom surface 4S, and in the present example, the tip is formed in an arc substantially aligned with the bottom surface 4S in the proximity state Y2. .

Also, the end portion 3 of the arm portion 33C of the lever 33
A biasing means 40 for biasing the end 33e inward in the radial direction is linked to 3e.

That is, the urging means 40 is a cylindrical cylinder 41 bolted to the rear surface of the flange portion 20B.
And the outer end in the radial direction is loosely inserted in the cylinder 41 and slides in and out in the radial direction, and the arm portion end portion 33e is formed.
And a spring piece 43 mounted in the cylinder for biasing the rod 42 inward in the radial direction. In this example, the cylinder 41 is connected to the rod 42.
An abutting piece 44 is provided which determines the slide end position Q1 of the rod 42 inward in the radial direction by abutting on the inner end. Therefore, when the winding former 2 is reduced in diameter at the inner slide end position Q1, that is, when the support shaft 39 is moved inward in the radial direction, the rod 42 acts like pushing the arm end 33e outward in the radial direction. Then, a counterclockwise moment is generated in the figure centered on the support shaft 39. As a result, the tip of the grip portion 33B can move to the separated state Y1 in which the tip of the grip portion 33B is located on the groove wall F2 side.

When the winding former 2 is expanded in diameter from the separated state Y1, a clockwise moment is generated conversely, and the tip of the grip portion 33B can move to the close state Y2 located on the groove wall F1 side. When the diameter expansion further proceeds, the rod 42 is dragged by the lever 33 and slides outward from the inner slide end position Q1 in the radial direction. At this time, the urging force of the spring piece 43 is applied to the rod 42, so that the clockwise moment is generated. Is increased, and the winding start portion W1 can be clamped and held between the gripping surface 33S and the contact surface 36S.

As described above, the clamp means 12 can rotate the lever 33 in conjunction with the expansion / contraction diameter operation of the winding former 2, so that the winding start portion W1 can be automatically fixed.
Further, prior to the fixing, the grip portion 33B of the lever 33 moves from the separated state Y1 to the close state Y2, so that the interrupted portion 3
The winding start portion W1 supplied to the inside of the wire 1 can be captured regardless of the supply position, and the simplification of the wire supply means and the securement of the clamp can be promoted. It should be noted that, instead of the contact piece 44, in the vicinity of the diameter-reducing end of the winding former 2, the end portion of the arm portion 33C is pushed outward in the radial direction, so that the flange portion 20
You may make it contact B.

In this example, as shown in FIGS. 3 and 7, the above-mentioned holding of the bead wire W held above the winding former 2 in the reduced diameter state is released, and the bead wire W is naturally dropped into the interrupted portion 31. Therefore, the winding start part W
1 is supplied to the winding former 2. Therefore, in order to ensure this drop, in this example, the winding start portion W1 is interrupted by extending radially outward along the groove wall surface from the outside to both the outer end of the groove wall F1 and both sides of the interrupted portion 31. Guide piece 6 having a guide surface 61S for guiding inside the portion 31
1, 61 are provided.

Further, the mounting bracket 51 has the mounting bracket 51
A guide piece 62 having an outer end portion extending from the cutout portion 31 between the front plate piece 35B of the case body 35 and the lever 33 is attached. The outer end of the guide piece 62 is
In the reduced diameter state of the winding former 2, it has a guide surface 62S extending radially outward from the position of the outer end of the groove wall F2 along the groove wall surface and guides the drop of the winding start portion W1. Further, the outer end portion of the guide piece 62 is positioned so as to be radially inward from the groove bottom surface 4S of the winding former 2 in the expanded diameter state, which facilitates the removal of the completed bead core C from the winding former 2.

FIG. 13 shows another embodiment of the lever 33. In the figure, the lever 33 includes a pivotal support portion 33A formed of first and second pivotal support portions 33Aa and 33Ab pivotally supported around a pair of support shafts 39a and 39b arranged in parallel with each other. The pivot portions 33Aa and 33Ab are connected to each other via gear bodies 99 that mesh with each other. Further, the one pivotal support 33Aa has a gripping portion 33B having a gripping surface 33S.
However, on the other pivotal support 33Ab, rearwardly extending arm portions 33C are respectively formed. Therefore, the tilting motion of the grip portion 33B can be changed to the left or right, and the distal end of the grip portion 33B is moved from the separated state in which the tip of the grip portion 33B is located on the one groove wall F1 side to the close state in which it is located on the other groove wall F2 side in conjunction with the expansion / contraction diameter operation. Moving.

Further, FIG. 12 shows a bead core forming apparatus 1 of this example.
3 shows a bead core formation line L using In the figure, the bead wire W attached with a rubber in the standby / stop state of the bead core forming apparatus 1 in which the former 2 is reduced
Is a habit forming tool 70, a feed roller 71, and a guide tool 72.
The winding start portion W1 is held by the holder 73 passing through. Then, the winding platform W1 is moved to a position above the break 31 by the traveling of the traveling table 75 due to the expansion and contraction of the cylinder 74, and the winding start W1 is supplied into the break 31 by releasing the holder 73. In the bead core forming apparatus 1, after fixing the winding start portion W1 by the clamp means 12, the former 2 is rotated and the bead wire is wound around the concave groove 4. During this winding, the guide tool 72 intermittently laterally moves in the axial direction to form a spiral winding of the bead wire W. Cylinder 7 after winding
The holder 73 that descends at the standby position by the operation of Nos. 4 and 76.
However, the bead wire W is grasped and the cutter 77 cuts.

Here, the guide tool 72, the holder 73, and the cutter 77 are supported by a lateral moving table 78 that is laterally mounted on the traveling table 75, and the guide tool 72 is held by the cylinder 79 in the holder 73 and the holder 73. The cutter 77 is supported by the cylinder 76 so as to be able to descend.

[0047]

Since the bead core forming apparatus of the present invention is constructed as described above, the outer peripheral surface of the winding former can be expanded / contracted and the relative movement amount between the rotary cylinder and the center shaft can be adjusted. Thus, the diameter of the outer peripheral surface of the former when the diameter is expanded can be freely changed. As a result, bead cores having various inner diameters can be formed by using one former, and the production efficiency, management and storage efficiency can be greatly improved, and the inner diameter precision can be improved to form high quality bead cores.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a mounting state of a divided segment and a support shaft body.

FIG. 3 is a perspective view showing a clamp means.

FIG. 4 is a cross-sectional view showing a clamp means.

FIG. 5 is a perspective view showing a clamp unit.

FIG. 6 is a cross-sectional view illustrating a discontinuous portion.

FIG. 7 is a cross-sectional view illustrating a stopper.

FIG. 8 is a sectional view showing another embodiment of the stopper.

FIG. 9 is a cross-sectional view showing a tire.

FIG. 10 is an enlarged sectional view showing the bead core.

FIG. 11 is a sectional view illustrating a conventional technique.

FIG. 12 is a schematic view showing an example of a bead core forming line using the device of the present invention.

FIG. 13 is a cross-sectional view showing another example of the clamp means.

[Explanation of symbols]

 2 Winding former 3 Support shaft body 4 Recessed groove 5 Rotating cylinder 6 Inner hole 7 Middle shaft 10 Link body 11 Stopper 13 Frame 27 Split segment C Bead core T Tire W Bead wire

Claims (1)

[Claims] 1. A bead core of a tire is formed by winding a bead wire around the grooved former of a winding former having a grooved outer peripheral surface provided on a rotatable spindle while being supported by a frame. In the bead core forming device, the support shaft body includes a rotary cylinder having an inner hole concentric with the shaft center of the support shaft body, and a rotary cylinder that is loosely inserted in the inner hole to face the rotary cylinder in the axial center direction. The winding former has a sector shape divided about the axis and has a plurality of concave grooves formed on the outer peripheral surface thereof. The divided segments are arranged on one of the rotary cylinder or the center shaft so as to be immovable in the axial direction and slidable in the radial direction in a plane perpendicular to the axial center. The one end of the link body is pivotally attached to the front end of the link body and the other end of the link body is pivotally supported to the other of the rotary cylinder or the center shaft so as to slide in the radial direction through the link body by the relative advancing / retreating movement. On the shaft,
A bead core forming device provided with a stopper capable of adjusting the relative movement amount.