The present invention relates to a method of manufacturing a coil spring and a coil spring manufacturing apparatus.
In a proposed coil spring manufacturing apparatus, as described in Patent Document 1, a rotating body is rotatably supported as a coil forming tool via a support pin by a support tool, and a wire rod being fed out is serially pressed against an outer circumferential surface of the rotating body so as to form the wire rod into a coil shape while rotating the rotating body by the movement of the wire rod.
This makes it possible to reduce a frictional resistance of the wire rod with respect to the rotating body outer circumferential surface against which the wire rod is pressed and causes a problem of frictional force at the time of forming the wire rod into a coil shape, so that a deterioration in quality can be suppressed even without plating, or applying a lubrication oil to, the wire rod, in forming of a coil spring.
However, in the coil spring manufacturing apparatus, since the rotating body is configured to rotate in accordance with the movement of the wire rod in contact with the rotating body outer circumferential surface, unless a frictional force of the wire rod with respect to the rotating body outer circumferential surface exceeds a resistance force (maximum static frictional force) of the rotating body with respect to the support tool (support pin), the wire rod slips on the outer circumferential surface of the rotating body and the rotating body does not rotate. Therefore, the wire rod must have a strength capable of enduring until the rotating body rotates with respect to the support tool (until the frictional force of the rotating body with respect to the support tool attains a dynamic frictional force through the maximum static frictional force) and, if a wire rod without such a strength is used, a coil spring acquired as a product may be low quality or the forming of the coil spring itself may become difficult.
The present invention was conceived in view of such a circumstance and it is therefore a first object of the present invention to provide a method of manufacturing a coil spring enabling precise forming of a coil spring even when various kinds of wire rods are used.
A second object is to provide a coil spring manufacturing apparatus enabling precise forming of a coil spring even when various kinds of wire rods are used.
To achieve the first object, the present invention is configured as a method of manufacturing a coil spring by serially pressing a wire rod being fed out against an outer circumferential surface of a rotating body serving as a coil forming tool to form the wire rod into a coil shape, and
as the wire rod is fed out, the rotating body is rotationally driven by a rotary drive force of a rotary drive source such that a portion pressed against the wire rod on the outer circumferential surface of the rotating body moves toward the same side as the advancing side of the wire rod.
According to this configuration, it is no longer necessary for the drive force to generate a frictional force between the rotating body outer circumferential surface and the wire rod so as to rotate the rotating body based on the rotary drive of the rotating body by the rotary drive source, so that a limitation on wire rod strength attributable to the generation of the frictional force can be eliminated.
The following forms can be taken as preferable configuration forms of the present invention (first aspect of invention) on the premise of the configuration of the present invention (first aspect of invention).
(1) In a configuration that can be achieved, when the rotating body is rotationally driven, a circumferential speed of the outer circumferential surface of the rotating body is set close to a feed speed of the wire rod by using the feed speed of the wire rod as a target value.
As a result, a slip between the wire rod and the rotating body can be suppressed as much as possible, and the wiring rod is no longer necessary to have a strength capable of enduring until the rotating body starts rotating with respect to a support tool (until the frictional force of the rotating body with respect to the support tool attains a dynamic frictional force through a maximum static frictional force) and is also no longer necessary to have even a strength exceeding a rotational resistance force (dynamic frictional force) of the rotating body rotating with respect to the support, so that even if the wire rod with a lower strength is used, a coil spring can be manufactured.
Since a slip of the wire rod on the outer circumferential surface of the rotating body can be suppressed as much as possible, a damage of the outer circumferential surface of the wire rod can be prevented with high reliability. Accordingly, when the wire rod is a coated wire, a coat can be restrained from peeling due to the damage based on the slip.
(2) In a configuration that can be achieved based on the premise of (1) described above,
a shaft-shaped pitch processing tool is provided, and when the wire rod is formed into a coil shape, the pitch processing tool is pressed against the wire rod to displace the wire rod in an axial direction of the coil spring to be formed for performing pitch processing, and
as the wire rod is fed out, the pitch processing tool is rotationally driven by a rotary drive force of a pitch processing tool rotary drive source such that a portion pressed against the wire rod on an outer circumferential surface of the pitch processing tool moves toward the same side as the advancing side of the wire rod.
As a result, not only a pitch can be applied to the formed coil spring, but also it is no longer necessary for the drive force to generate a frictional force between the pitch processing tool outer circumferential surface and the wire rod so as to rotate the pitch processing tool around the axis thereof, and therefore, even if the pitch processing tool is provided, a limitation on wire rod strength attributable to the generation of the frictional force can be eliminated.
(3) In a configuration that can be achieved based on the premise of (2) described above,
when the pitch processing tool is rotationally driven, a circumferential speed of the outer circumferential surface of the pitch processing tool is set close to a feed speed of the wire rod by using the feed speed of the wire rod as a target value.
As a result, in addition to the case of the rotating body, the pitch processing tool is configured in the same way, and even if the pitch processing tool is provided, the coil spring can precisely be formed and, moreover, a slip of the wire rod on the outer circumferential surface of the pitch processing tool can be suppressed as much as possible to prevent a damage of the outer circumferential surface of the wire rod with high reliability.
(4) In a configuration that can be achieved, a shaft-shaped pitch processing tool is provided, and when the wire rod is formed into a coil shape, the pitch processing tool is pressed against the wire rod to displace the wire rod in an axial direction of the coil spring to be formed for performing pitch processing, and
as the wire rod is fed out, the pitch processing tool is rotationally driven by a rotary drive force of a pitch processing tool rotary drive source such that a portion pressed against the wire rod on an outer circumferential surface of the pitch processing tool moves toward the same side as the advancing side of the wire rod.
As a result, not only a pitch can be applied to the formed coil spring, but also it is no longer necessary for the drive force to generate a frictional force between the pitch processing tool outer circumferential surface and the wire rod so as to rotate the pitch processing tool around the axis thereof, and therefore, even if the pitch processing tool is provided, a limitation on wire rod strength attributable to the generation of the frictional force can be eliminated.
(5) In a configuration that can be achieved based on the premise of (4) described above,
when the pitch processing tool is rotationally driven, a circumferential speed of the outer circumferential surface of the pitch processing tool is set close to a feed speed of the wire rod by using the feed speed of the wire rod as a target value.
As a result, in addition to the case of the rotating body, the pitch processing tool is configured in the same way, and even if the pitch processing tool is provided, the coil spring can precisely be formed and, moreover, a slip of the wire rod on the outer circumferential surface of the pitch processing tool can be suppressed as much as possible to prevent a damage of the outer circumferential surface of the wire rod with high reliability.
To achieve the second object, the present invention is configured as a coil spring manufacturing apparatus comprising: a rotating body having an outer circumferential surface against which a wire rod being fed out is serially pressed for forming into a coil shape,
the rotating body being connected to a rotary drive source such that the rotating body is rotated around an axis of the rotating body,
the rotary drive source rotationally driving the rotating body as the wire rod is fed out, the rotary drive source being set in relation to the rotary drive of the rotating body such that a portion pressed against the wire rod on the outer circumferential surface of the rotating body moves toward the same side as the advancing side of the wire rod.
With this configuration, as the wire rod is fed out, the rotating body is rotationally driven by the rotary drive force of the rotary drive source such that a portion pressed against the wire rod on the outer circumferential surface of the rotating body moves toward the advancing side of the wire rod, so that a coil spring manufacturing apparatus implementing the method of manufacturing a coil spring (the first aspect of invention) described above can be provided.
The following forms can be taken as preferable configuration forms of the present invention (second aspect of invention) on the premise of the configuration of the present invention (second aspect of invention).
(1) In a configuration that can be achieved, the rotary drive source is adjusted to set a circumferential speed of the outer circumferential surface of the rotating body close to a feed speed of the wire rod by using the feed speed of the wire rod as a target value.
As a result, a coil spring manufacturing apparatus implementing the method of (1) in the first aspect of invention can be provided.
(2) In a configuration that can be achieved based on the premise of (1) described above,
the coil spring manufacturing apparatus comprises a wire rod guide straightly feeding out the wire rod, and a winding tool disposed adjacent to the wire rod guide to wind a wire rod fed out from the wire rod guide therearound, the rotating body is made up of a single rotating body,
the winding tool has an arc-shaped outer circumferential surface around which the wire rod fed from the wire rod guide is wound, and
the single rotating body is disposed to be bought into contact with the arc-shaped outer circumferential surface of the winding tool via the wire rod.
As a result, when a coil spring of a normal size is formed, the wire rod can obviously precisely be wound into a coil shape by a leading end of the wire rod guide, the single rotating body, and the winding tool, and even when the diameter of the coil spring to be formed is extremely small, a problem of interference between rotating bodies can be eliminated unlike the case of using a plurality of rotating bodies. Therefore, even in the case of forming a coil spring having an extremely small diameter, the coil spring can precisely be formed.
(3) In a configuration that can be achieved based on the premise of (1) described above,
the coil spring manufacturing apparatus comprises a shaft-shaped pitch processing tool pressed against the wire rod to displace the wire rod in an axial direction of the coil spring to be formed for performing pitch processing when the wire rod is formed into a coil shape,
the pitch processing tool is connected to a pitch processing tool rotary drive source such that the pitch processing tool is rotated around an axis of the pitch processing tool, and
the pitch processing tool rotary drive source rotationally drives the pitch processing tool as the wire rod is fed out, and is set in relation to the rotary drive of the pitch processing tool such that a portion pressed against the wire rod on an outer circumferential surface of the pitch processing tool moves toward the same side as the advancing side of the wire rod.
As a result, a coil spring manufacturing apparatus implementing the method of (2) in the first aspect of invention can be provided.
(4) In a configuration that can be achieved based on the premise of (3) described above,
the pitch processing tool rotary drive source is adjusted to set a circumferential speed of the outer circumferential surface of the pitch processing tool close to a feed speed of the wire rod by using the feed speed of the wire rod as a target value.
As a result, a coil spring manufacturing apparatus implementing the method of (3) in the first aspect of invention can be provided.
(5) The coil spring manufacturing apparatus comprises a shaft-shaped pitch processing tool pressed against the wire rod to displace the wire rod in an axial direction of the coil spring to be formed for performing pitch processing when the wire rod is formed into a coil shape,
the pitch processing tool is connected to a pitch processing tool rotary drive source such that the pitch processing tool is rotated around an axis of the pitch processing tool, and
the pitch processing tool rotary drive source rotationally drives the pitch processing tool as the wire rod is fed out, and is set in relation to the rotary drive of the pitch processing tool such that a portion pressed against the wire rod on an outer circumferential surface of the pitch processing tool moves toward the same side as the advancing side of the wire rod.
As a result, a coil spring manufacturing apparatus implementing the method of (4) in the first aspect of invention can be provided.
(6) In a configuration that can be achieved based on the premise of (5) described above,
the pitch processing tool rotary drive source is adjusted to set a circumferential speed of the outer circumferential surface of the pitch processing tool close to a feed speed of the wire rod by using the feed speed of the wire rod as a target value.
As a result, a coil spring manufacturing apparatus implementing the method of (5) in the first aspect of invention can be provided.
From the above, the present invention can provide a method of manufacturing a coil spring and a coil spring manufacturing apparatus enabling precise forming of a coil spring even when various kinds of wire rods are used.
Embodiments of the present invention will now be described with reference to the drawings.
Before explaining a method of manufacturing a coil spring by forming a wire rod used as a forming material into a coil spring, a coil spring manufacturing apparatus using the method will first be described.
As shown in
The pair of the feed rollers 2a, 2b are arranged in a vertical relationship so as to feed a wire rod M toward the wire rod guide 3. The paired feed rollers 2a, 2b have respective rotation axes O1 oriented in a direction (direction perpendicular to the plane of
To guide the wire rod M fed out from the pair of the feed rollers 2a, 2b in a straightly extended manner, as shown in
As shown in
In the present embodiment, the cored bar 4 is integrally attached to an attaching member not shown. The cored bar 4 is extended in a shaft shape in the same direction as the axes O1 of the feed rollers 2a, 2b, and a leading end portion of the cored bar 4 is disposed adjacent to the wire rod guide 3 at a position above a leading end opening of the guide hole 12 of the wire rod guide 3. This cored bar 4 is formed into a substantially semicircular shape in a front view of
The cored bar 4 has a diameter corresponding to the inner diameter of the coil spring to be formed and, if the inner diameter of the coil spring to be formed is made extremely small, the cored bar 4 having an extremely small diameter of 1 mm or less may accordingly be used.
In
As shown in
A band plate-shaped member is used for the base 17, and the base 17 has one end side disposed close to the wire rod guide 3 and the cored bar 4 and the other end side attached to an attaching member not shown with a longitudinal direction thereof oriented in the extension direction of the coil spring manufacturing apparatus 1 (the horizontal direction of
As shown in
Specifically, in the state of the wire rod M guided from the leading end opening P1 of the guide hole 12 to the point P2 on the outer circumferential surface of the rotating roller 5, the wire rod M is formed into a curved shape along the first outer circumferential surface portion 14a based on pressing against the outer circumferential surface 5a of the rotating roller 5. When the wire rod M is further fed out and a curvature forming portion formed into a curved shape at the point P1 and the point P2 reaches an end P3 of the second outer circumferential surface part 14b in the winding direction of the wire rod M (counterclockwise direction of
As shown in
As shown in
For forming a coil spring, the pitch processing tool 6 is formed into a shaft shape as shown in
The cutter 7 is coupled to a servomotor 24 serving as a rotary drive source via a reciprocation converting mechanism 23 as shown in
In this coil spring manufacturing apparatus 1, various kinds of wire rods can be used as the wire rod M. Specifically, from the viewpoint of material, spring steel wires represented by stainless steel wires, piano wires, etc. and soft wires represented by copper wires, platinum wires, etc. are usable; from the viewpoint of diameter, not only those in a typical range of 0.3 to 5.0 mm but also those having an extremely small diameter, for example, less than 0.3 mm are usable depending on the intended use; and furthermore, a coated wire having a core material coated with a resin (e.g., a fluororesin such as polytetrafluoroethylene) can also be used as the wire rod M.
As shown in
Therefore, input information from an operation input part 25 and input information (feed information of the wire rod M) from an encoder 26 in the servomotor 8 are input to the control unit U, and control signals are output from the control unit U to the servomotor 8, the servomotor 20, and the servomotor 24.
As shown in
Various programs, setting information, etc. necessary for forming a coil spring are stored in the storage part 27, and these various programs etc. are read out by the control calculation part 28 as needed. Additionally, necessary information is stored as appropriate.
As shown in
The setting part 29 sets a feed length of the wire rod M, a speed of feeding of the wire rod M by the feed rollers 2a, 2b, a circumferential speed of the rotating roller outer circumferential surface 5a, etc. for forming a predetermined coil spring, and the control part 30 outputs various control signals under the various programs to the servomotor 8, the servomotor 20, and the servomotor 24 based on the setting information in the setting part 29.
A specific operation of the coil spring manufacturing apparatus 1 according to the present embodiment will be described together with a method of manufacturing a coil spring used in the coil spring manufacturing apparatus 1.
When the wire rod M is formed into a predetermined coil spring, the predetermined coil spring and the subsequent wire rod M are cut at the point P3 (see
When the coil spring manufacturing apparatus 1 determines that forming of a new coil spring should be started, the pair of the feed rollers 2a, 2b is rotationally driven and the wire rod M is fed out toward the wire rod guide and the fed wire rod M is serially curved and formed into a coil shape by the wire rod guide 3, the cored bar 4, and the rotating roller 5 (see
Subsequently, when the coil spring manufacturing apparatus 1 determines that the predetermined coil spring is formed from the wire rod M fed out by a predetermined length by the rotation of the pair of the feed rollers 2a, 2b, the rotary drive of the pair of the feed rollers 2a, 2b is stopped, and the wire rod M placed on the cored bar 4 (the point P3) is then cut by the cutter 7.
In this case, in the present embodiment, the rotating roller 5 is rotationally driven in synchronization with the rotary drive of the feed rollers 2a, 2b. The form of the present embodiment will be described in detail in comparison with a comparative example having a form in which the rotating roller 5 is not rotationally driven by a rotary drive source and is simply rotatably supported by a support tool 31 via a support pin 32 (see
(1) Case of Form of Comparative Example (See
When the wire rod M is fed out by the pair of the feed rollers 2a, 2b under the state in which the wire rod M pulled out from the wire rod guide 3 is pressed against the outer circumferential surface of the rotating roller 5, a frictional force is generated as shown in
Therefore, in the case of the wire rod M having a particularly low wire rod strength such as the soft wires described above and the wire rod M having a diameter less than 0.3 mm, it is not easy to forma coil spring because of occurrence of buckling etc.
Additionally, since the wire rod M slips on the outer circumferential surface of the rotating roller 5 until the frictional force of the rotating roller 5 with respect to the support pin 32 reaches the maximum static frictional force, the outer circumferential surface of the wire rod M may be damaged based on the slip. Therefore, if the wire rod M is a coated wire having a core material coated with a resin, peeling may occur in a coat thereof due to a damage based on the slip. Particularly, if a guide groove (corresponding to the guide groove 19 of the present embodiment) is formed on the outer circumferential surface of the rotating roller 5, an opening edge etc. of the guide groove 19 may locally act on the outer circumferential surface of the coated wire, and the peeling of the coat may be promoted by a slip occurring therebetween.
(2) Case of Form of Present Embodiment (See
(i) In contrast, in the present embodiment, the rotating roller 5 is rotationally driven by the servomotor 20 in synchronization with the rotary drive of the feed rollers 2a, 2b such that a portion pressed against the wire rod M on the rotating roller outer circumferential surface 5a moves to the same side as the advancing side of the wire rod M (rotationally driven in the clockwise direction of
(ii) Particularly, if the rotating roller 5 is rotationally driven such that the circumferential speed of the rotating roller outer circumferential surface 5a is made as close as possible to the feed speed of the wire rod M by using the feed speed of the wire rod M as a target value (most preferably, if the feed speed of the wire rod M and the circumferential speed of the roller outer circumferential surface 5a are made equal), a slip between the wire rod M and the rotating roller outer circumferential surface 5a can almost be eliminated, and the wiring rod M is no longer necessary to have the strength capable of enduring until the rotating roller 5 starts rotating with respect to the support tool (until the frictional force of the rotating body with respect to the support tool attains the dynamic frictional force through the maximum static frictional force) and is also no longer necessary to have even a strength exceeding a rotational resistance force (dynamic frictional force) of the rotating roller 5 rotating with respect to the support pin 32 described above, so that even if the wire rod M with an extremely low strength is used, a coil spring can be manufactured.
(iii) Therefore, even when a wire rod with a particularly low wire rod strength such as the soft wire described above and the wire rod M having a diameter less than 0.3 mm is used as the wire rod M, the wire rod M can precisely be formed into a coil spring without causing buckling etc.
(iv) In this case, if a wire rod having a diameter less than 0.3 mm is used as the wire rod M to forma coil spring having an inner diameter of about 1 mm, the coil spring can be used as a contact probe, a catheter, etc., and in the forming of such a coil with an extremely small diameter, the coil spring manufacturing apparatus 1 described above provided with the only one rotating roller 5 (see
Description will specifically be made with reference to
In this coil spring manufacturing apparatus 1, the two rotating rollers 5 are respectively arranged at an angle of about 45 degrees above and below a horizontal line passing through an axis of a coil spring to be formed, and the wire rod M is pressed in a curved state against the rotating rollers 5. As a result, this coil spring manufacturing apparatus 1 can precisely form the wire rod M into the coil spring at points P2-1, P2-2 of pressing by the two rotating rollers 5 against the wire rod M and the point P1 at the leading end opening of the guide hole 12 of the wire rod guide 3 for the wire rod M (three points) (in
However, for example, when a wire rod having a diameter less than 0.3 mm is used as the wire rod M to forma coil spring having a diameter equal to or less than the diameter of each of the rotating rollers 5, although the diameter of the cored bar 4 can be reduced as the diameter of the coil spring to be formed becomes smaller, the outer diameter of each of the two rotating rollers 5 cannot be reduced so much, while the arrangement relationship between the two rotating rollers 5 (respectively pressing against the wire rod M from the angular positions of approx. 45 degrees above and below the horizontal line) cannot be changed even if the diameter of the coil spring to be formed becomes smaller. Therefore, in the coil spring manufacturing apparatus including the two rotating rollers 5, the possibility of interference between the two rotating rollers 5 increases as the diameter of the coil spring to be formed is made smaller (see an interval indicated by an arrow between the two rollers 5, 5 in
(v) If the circumferential speed of the rotating roller outer circumferential surface 5a is made substantially equal to the feed speed of the wire rod M, the slip of the wire rod M on the rotating roller outer circumferential surface 5a can almost be eliminated, and the outer circumferential surface of the wire rod M can be prevented from being damaged based on the slip M. Accordingly, if the wire rod is a coated wire, the peeling of the coat caused due to the damage based on the slip can be prevented and, under the condition that the guide groove 19 is formed on the rotating roller outer circumferential surface 5a, the peeling of the coat of the coated wire based on the guide groove 19 can be prevented.
Specific operations of the method of manufacturing a coil spring according to the present embodiment and the coil spring manufacturing apparatus 1 using the method of manufacturing a coil spring will more specifically be described with reference to a flowchart of
When the coil spring manufacturing apparatus 1 is started, at S1, various pieces of information are read such as the length of feeding of the wire rod M at a time by the feed rollers 2a, 2b, the speed of feeding of the wire rod M by the feed rollers 2a, 2b, and the circumferential speed of the rotating roller outer circumferential surface 5a (the speed substantially equal to the speed of feeding of the wire rod M by the feed rollers 2a, 2b) and, when the reading is completed, the rotations of the feed rollers 2a, 2b and the rotating roller 5 are started at S2 at the same time. In this case, the speed of feeding of the wire rod M by the feed rollers 2a, 2b is substantially equal to the circumferential speed of the outer circumferential surface 5a of the rotating roller 5, so that the frictional force of the wire rod M with respect to the rotating roller outer circumferential surface 5a can almost be eliminated. Therefore, various kinds of wire rods can be formed as the wire rod M, including not only those having a normal diameter (normal strength) but also those having a low wire rod strength, or particularly, those used for making the diameter of the coil spring to be formed extremely small.
At next step S3, it is determined based on an output signal from the encoder 26 in the servomotor 8 whether the feed rollers 2a, 2b have fed out the wire rod M by a predetermined length. This is performed for determining whether a coil spring with a predetermined axial length is formed. When S3 is NO, the determination of S3 is repeated to continue the forming of the coil spring, and when S3 is YES, the rotary drives of the feed rollers 2a, 2b and the rotating roller 5 are stopped at S4. This is because it is determined that a coil spring having a predetermined axial length is formed.
Subsequently, at S5, the cutter 7 is moved downward, and the cutter 7 and the cored bar 4 (the cutter guide surface 13) cooperate to cut off the formed coil spring from the subsequent wire rod M. When S5 is completed, a return is made to S2 described above so as to form the next coil spring.
In the second embodiment shown in
Specifically, a pitch processing tool servomotor 33 is connected to the pitch processing tool 6 so as to rotate the pitch processing tool 6 around the axis O3, and the servomotor 33 rotationally drives the pitch processing tool 6 as the wire rod M is fed out, and is set in relation to the rotary drive of the pitch processing tool 6 such that a portion pressed against the wire rod M on the outer circumferential surface of the pitch processing tool 6 moves toward the same side as the advancing side of the wire rod M. Moreover, the circumferential speed of the outer circumferential surface of the pitch processing tool 6 is also set substantially equal to the speed of feeding of the wire rod M by the feed rollers 2a, 2b.
As a result, not only the pitch can be applied to the formed coil spring, but also it is no longer necessary for the drive force to generate a frictional force between the outer circumferential surface of the pitch processing tool 6 and the wire rod M so as to rotate the pitch processing tool 6 around the axis O3, and therefore, even if the pitch processing tool 6 is provided, a problem of the strength of the wire rod M attributable to the generation of the frictional force can be eliminated.
First, at first step S1′, the circumferential speed of the outer circumferential surface of the pitch processing tool 6 around the axis thereof (set substantially equal to the speed of feeding of the wire rod M by the feed rollers 2a, 2b) is also read as the various pieces of information in addition to those of the first embodiment described above, and the rotations of the feed rollers 2a, 2b, the rotating roller 5, and the pitch processing tool 6 are started at S2′ to start the coil spring forming for the wire rod M. In this case, since the circumferential speed of the outer circumferential surface of the rotating roller 5 and the circumferential speed of the outer circumferential surface of the pitch processing tool 6 are substantially equal to the speed of feeding of the wire rod M by the feed rollers 2a, 2b, the frictional force between the outer circumferential surface and the wire rod M can be kept considerably low not only for the rotating roller 5 but also for the pitch processing tool 6.
After the process of S2′ is completed, if it is determined in the determination of next step S3 that the wire rod M has been fed out by a predetermined length and a coil spring having a predetermined axial length has been formed, the operation goes to S4′, and the rotations of the feed rollers 2a, 2b, the rotating roller 5, and the pitch processing tool 6 are stopped at S4′. At next step S5, the formed coil spring is cut off from the subsequent wire rod M, and a return is made to S2′ described above so as to manufacture a new coil spring.
The third embodiment shown in
In the coil spring manufacturing apparatus 1 according to the third embodiment, the columnar cored bar 4 is arranged to cross the feed direction of the wire rod M from the wire rod guide 3 (the rightward direction of
In this case, the cored bar 4 may independently be rotationally driven by a rotary drive source, and the circumferential speed of the outer circumferential surface of the cored bar 4 may be made equal to the circumferential speed of the rotating roller outer circumferential surface 5a.
Although the embodiments have been described, the present invention include the following forms.
(1) The guide groove 11a (11b) is formed only on the mating surface 10a (10b) of the one guide member 9a (9b) out of a pair of the guide members 9a, 9b, and the guide hole 12 is made up of the guide groove 11a (11b) inside the wire rod guide 3.
(2) An integrally molded product having a through-hole as the guide hole 12 is used as the wire rod guide 3.
(3) The rotating shaft 15 etc. are used as a rotating body.
(4) The arrangement of the pitch processing tool is determined depending on a winding direction of the coil spring to be formed. In particular, when the coil spring to be formed is a right-handed spring, the tool is allowed to enter the coil spring to be formed from obliquely above (see
Accordingly, when the coil spring to be formed is a left-handed spring, the cutter 7 is disposed on the lower side of the coil spring to be formed.
The present application is a U.S. National Phase of PCT/JP2015/068348 filed on Jun. 25, 2015. The disclosure of the PCT application is hereby incorporated by reference into the present application.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/068348 | 6/25/2015 | WO | 00 |