Patent Publication Number: US-6701765-B2

Title: Spring manufacturing apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to a spring manufacturing apparatus for manufacturing springs having various shapes by forcibly bending, curving, or winding wires to be formed into springs with tools while continuously feeding the wires. 
     BACKGROUND OF THE INVENTION 
     In a conventional spring manufacturing apparatus, tools are respectively driven/controlled by independent servo motors and placed at arbitrary angles around a wire. 
     The tool positions are, however, finely adjusted by a skilled operator by hunching in accordance with a desired spring shape. This operation is difficult to repeat, and hence is a most time-consuming operation. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in consideration of the above problem, and has as its object to provide a spring manufacturing apparatus which can execute fine adjustments on the positions of a plurality of tools with respect to the wires fed out from the wire guides by automatic control with high accuracy in a short period of time. 
     In order to solve the above problem and achieve the above object, according to the present invention, there is provided a spring manufacturing apparatus for manufacturing a spring by feeding a wire to be formed into a spring out of an end portion of a wire guide, and forcibly bending, curving, or winding the wire by using a tool in a spring forming space near an end portion of the wire guide, wherein a plurality of tools are arranged to extend radially with respect to wires fed into the spring forming spaces, supported to be slidable toward the wires fed into the spring forming spaces, and supported to allow the end portions of the tools to simultaneously swing with respect to the wires fed out from the end portions of the wire guides. 
     As described above, according to the present invention, since a plurality of tools are supported to allow the end portions of the tools to simultaneously swing with respect to the wires fed out from the end portions of wire guides, fine adjustments on the positions of a plurality of tools with respect to the wires fed out from the wire guides can be simultaneously executed by automatic control with high accuracy in a short period of time. 
     Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the outer appearance of a spring manufacturing apparatus according to an embodiment when viewed from the front side; 
     FIG. 2 is a perspective view showing the outer appearance of the spring manufacturing apparatus according to this embodiment when viewed from the rear side; 
     FIG. 3 is a front view showing the spring manufacturing apparatus according to this embodiment; 
     FIG. 4 is a rear view showing the spring manufacturing apparatus according to this embodiment; 
     FIG. 5 is a side view showing the spring manufacturing apparatus according to this embodiment; 
     FIG. 6 is a perspective view showing the outer appearance of a curving tool unit; 
     FIG. 7 is a plan view showing the curving tool unit; 
     FIG. 8 is a side view showing the curving tool unit; 
     FIG. 9 is a perspective view showing the outer appearance of a rotating tool unit; 
     FIG. 10 is a plan view showing the rotating tool unit; 
     FIG. 11 is a side view showing the rotating tool unit; 
     FIG. 12 is a perspective view showing the outer appearance of a table including a swing ring; 
     FIG. 13 is a front view showing the swing ring; 
     FIG. 14 is a plan view showing a driving mechanism for the swing ring; 
     FIG. 15 is a sectional view taken along a line I—I in FIG. 14; 
     FIG. 16 is a view showing rotating tool bending in two-dimensional forming; 
     FIG. 17 is a view showing rotating tool bending in two-dimensional forming; 
     FIG. 18 is a view showing tool bending in two-dimensional forming; 
     FIG. 19 is a view showing tool bending in two-dimensional forming; 
     FIG. 20 is a view showing a rotating tool winding process in three-dimensional forming; 
     FIG. 21 is a view showing the rotating tool winding process in three-dimensional forming; 
     FIG. 22 is a view showing a coiling process in three-dimensional forming; 
     FIG. 23 is a view showing the coiling process in three-dimensional forming; 
     FIG. 24 is a view showing a pitched coiling process in three-dimensional forming; 
     FIG. 25 is a view showing the pitched coiling process in three-dimensional forming; 
     FIG. 26 is a view showing a hook raise process in three-dimensional forming; 
     FIG. 27 is a view showing the hook raise process in three-dimensional forming; 
     FIG. 28 is a view showing the hook raise process in three-dimensional forming; 
     FIG. 29 is a view showing press forming; 
     FIG. 30 is a view showing press forming; 
     FIG. 31 is a view showing cutting and tool bending after cutting; 
     FIG. 32 is a view showing cutting and tool bending after cutting; 
     FIG. 33 is a view showing cutting and tool bending after cutting; 
     FIG. 34 is a view showing cutting and tool bending after cutting; and 
     FIG. 35 is a block diagram showing the arrangement of a controller for the spring manufacturing apparatus. 
    
    
     Other objects and advantages besides those discussed above shall be apparent to those skilled in the art from the description of a preferred embodiment of the invention which follows. In the description, reference is made to accompanying drawings, which form a part thereof, and which illustrate an example of the invention. Such example, however, is not exhaustive of the various embodiments of the invention, and therefore reference is made to the claims which follow the description for determining the scope of the invention. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 
     Note that the embodiment described below is an example of means of implementing the present invention, and can be modified and changed without departing from the spirit and scope of the invention. 
     Arrangement of Spring Manufacturing Apparatus 
     FIG. 1 is a perspective view showing the outer appearance of a spring manufacturing apparatus according to this embodiment when viewed from the front side. FIG. 2 is a perspective view showing the outer appearance of the spring manufacturing apparatus according to the embodiment when viewed from the rear side. FIG. 3 is a front view of the spring manufacturing apparatus according to the embodiment. FIG. 4 is a rear view of the spring manufacturing apparatus according to the embodiment. FIG. 5 is a side view of the spring manufacturing apparatus according to the embodiment. 
     As shown in FIGS. 1 to  5 , the spring manufacturing apparatus according to this embodiment includes a regular octagonal table  200  which has an opening in its central portion and is mounted on a box-like base (not shown), a wire feeder  300  placed on the rear surface of the table  200 , and a plurality of tool units  400  arranged on the front surface of the table  200  to extend radially around the opening (wire axis). 
     The wire feeder  300  includes a wire feed mechanism  310  for supplying a wire to be formed into a spring, a wire feed roller pair  320  for feeding the wire from the wire feed mechanism  310 , and a wire guide  330  for guiding the wire pushed out by the wire feed roller pair  320  into a spring forming space. 
     The wire feed roller pair  320  feeds a wire out of the end portion of a wire insertion hole formed in the wire guide  330  by rotating each roller in the wire feed direction while clamping the wire with the pair of opposing rollers. 
     The wire feed roller pair  320  and wire guide  330  can rotate around the wire axis to twist a wire while clamping it with the pair of rollers. 
     The tool units  400 , at least one tool unit, which form springs having desired shapes by forcibly bending, curving, winding, or cutting wires radially extend from the respective sides of the octagon of the table  200  toward the spring forming spaces while being arranged to be slidable along the wires fed into the spring forming spaces. 
     Each tool unit  400  is slid by a corresponding one of crank mechanisms  409  which are arranged at the respective sides of the table  200  to convert rotational motions into translational motions and use servo motors as driving sources, and are supported to swing on the rear end portions of the tool units. In addition, if the tool unit  400  has a rotating tool that rotates about a tool shaft, a servo motor for rotating the tool shaft is added as a driving source. 
     Tool Unit 
     A curving tool unit  410  for curving the wire fed out from the wire guide  330  as shown in FIGS. 6 to  8 , a rotating tool unit  420  for winding the wire fed out from the wire guide  330  as shown in FIGS. 9 to  11 , a cutting tool (not shown), and the like are mounted on the table  200 . 
     Each tool unit  400  includes a slider  401  for holding tools T 1  and T 2 , a slide rail  402  for axially supporting the slider  401  to allow it to freely slide or rotate around the tool shaft, and a slide base  403  for holding the slide rail  402 . The rotating tool unit  420  has a rotating shaft  421  for rotating/driving the rotating tool T 2  around the tool shaft while slidably supporting the rotating tool T 2  with the slider  401 , and a servo motor  422  for rotating/driving the driving shaft. 
     The slide base  403  is mounted on the front surface of the table  200  such that the slide base can rotate about a shaft hole  404  in which the slide mechanism is mounted, and the rotation is restricted by a plurality of elliptic rotation restricting holes  405  symmetrically formed in two side portions of the middle portion of the base. Protruding shafts formed on the table  200  at positions corresponding to the rotation restricting holes  405  are movably inserted therein. 
     A swing hole  406  for giving a driving force to the tool unit  400  to make it swing is formed in the end portion of the slide base  403  which is located on the spring forming space side. A roller mounted on a swing ring  450  (to be described later) is inserted into the swing hole  406  and clamped with a pair of bridges  407 . 
     The end portion of the tool unit  400  which is located far from the wire fed out from the end portion of the wire guide  330  is rotatably supported by the shaft hole  404 , whereas the end portion of the tool unit which is located near the wire is supported by the swing ring  450  which is rotated/driven at a predetermined angle around the wire fed out from the end portion of the wire guide  330 . 
     The tool unit  400  is supported by the shaft hole  404 , rotation restricting hole  405 , swing hole  406 , and swing ring  450  (to be described later) to swing at a predetermined angle around the wire fed out from the end portion of the wire guide  330 . 
     Each of these tool units is detachably mounted on the table  200 . The types, positions, and the like of tools can be arbitrarily set. 
     As the tool units  400 , tools other than the above tools, e.g., a bending tool, holding tool, and cutting tool can be mounted. 
     Support Structure for Tool Unit 
     FIGS. 12 and 13 are views showing a swing support structure for each tool unit  400 . 
     As shown in FIGS. 12 and 13, the annular swing ring  450  for swinging the tool unit  400  is rotatably mounted on the central portion of the table  200  to be centered on the wire, and has a protruding piece  451  protruding from a portion of its circumferential portion and a pair of swing rollers  452  that are mounted to correspond to the mounting position of the tool unit  400 . 
     The swing ring  450  has an inner ring  450   a  and outer ring  450   b . The inner ring  450   a  and outer ring  450   b  can rotate relative to each other. By fixing the inner ring  450   a  of the swing ring  450  on the central portion of the table  200 , the outer ring  450   b  is rotatably supported. 
     The swing rollers  452  are axially supported on one side surface of the swing ring  450  to be rotatable. 
     An arm  461  of a driving mechanism  460  placed on the rear surface of the table  200  as shown in FIGS. 14 and 15 is coupled to the protruding piece  451  of the swing ring  450 . The swing ring  450  is pushed and pulled by a servo motor  462  to rotate within a restricted range. Upon rotation of this swing ring  450 , the tool unit  400  swings at a predetermined angle around the wire fed out from the end portion of the wire guide  330 . 
     The plurality of tool units  400 , each having the swing rollers  452  clamped with the bridges  407  in the swing hole  406 , simultaneously swing upon rotation of the swing ring  450 . In addition, when the tool unit  400  is fixed in a bolt hole  408  upon removal of the bridges  407 , the swing rollers  452  can freely move within the swing hole  406 . In this arrangement, therefore, when the swing ring  450  rotates, the tool unit  400  does not swing. That is, by choosing between clamping the swing rollers  452  with the bridges  407  and not clamping them, all or some of the tool units  400  can be supported so as not to swing. This makes it possible to select tool units  400  which should swing simultaneously. 
     According to the above arrangement, the end portions of a plurality of tools are supported such that the tools simultaneously swing with respect to the wires fed out from the end portions of the wire guides. These tools can be driven by automatic control using motors. This makes it possible to simultaneously make fine adjustments on a plurality of tool positions with respect to the wires fed out from the wire guides by automatic control with high accuracy in a short period of time. 
     Example of Wire Forming by Various Tools 
     FIG. 16 and 17 show rotating tool bending in two-dimensional forming. 
     When rotating tool bending is to be performed in two-dimensional forming, the rotating tool T 2  rotates in the bending direction of a wire W to bend the wire W with its end portion, thereby forming, for example, a hook portion of a spring. In this rotating tool bending, the wire can be bent without damaging it. 
     FIGS. 18 and 19 show tool bending in two-dimensional forming. 
     When tool bending is to be performed in two-dimensional forming, opposing tools T 3  are slid upward/downward by crank mechanisms to bend the wire W. This tool bending is used when there is no space for a rotating tool. 
     FIGS. 20 and 21 show a rotating tool winding process in three-dimensional forming. 
     When a rotating tool winding process is to be performed in three-dimensional forming, the rotating tool T 2  rotates to wind the wire W around its end portion to form, for example, a coil portion of a spring. This rotating tool winding process can form a spring with a small ratio of the coil outer diameter to the wire diameter. This process can realize a high-precision coil inner diameter, in particular, and is suited to clutch springs and the like. In addition, the process is suited to forming of wires having cross-sections other than round cross-sections (e.g., wires having rectangular cross-sections). 
     FIGS. 22 and 23 show coiling in three-dimensional forming. 
     When coiling is to be performed in three-dimensional forming, the wire W is pushed out to forcibly bring it into contact with the end portion of the abutment tool T 1  and wind it on the inclined surface of the wire guide  330 , thereby forming, for example, a coil portion of a spring. This coiling process can easily change the outer diameter of a coil and facilitate control on the winding angle of the coil. In addition, by changing the groove position of the end portion of the abutment tool T 1 , an initial tensile force and pitch can be easily set. 
     FIGS. 24 and 25 show a pitched coiling process in three-dimensional forming. 
     When a pitched coiling process is to be performed in three-dimensional forming, the wire W is pushed out to forcibly bring it into contact with the end portion of the abutment tool T 1  and wind it on the inclined surface of the wire guide  330 . During this operation, a pitch tool T 4  is interposed to provide pitches between coil elements, thereby forming, for example, a coil portion of a spring. This pitched coiling process allows easy setting of pitches in coil forming. 
     FIGS. 26 to  28  show a hook raise processing in three-dimensional forming. 
     In a hook raise process, the hook portion that has already been formed by the rotating tool T 2  or abutment tool T 1  by two-dimensional forming is further bent into a three-dimensional shape by using hook raise tools T 5  and T 6 . 
     When a hook raise process is to be performed in three-dimensional forming, the hook portion obtained by two-dimensional forming by pushing out the wire W and forcibly bringing it into contact with the end portion of the abutment tool T 1  is bent into a three-dimensional shape. 
     FIGS. 29 and 30 show press forming. 
     In press forming, the wire W is clamped between opposing crank bending tools T 7  to be formed into a crank-like shape or the like. 
     When press forming is to be performed, the opposing press tools T 7  are slid upward/downward by crank mechanisms to clamp and bend the wire W. This press forming is used to form the wire W into a special shape. 
     FIGS. 31 to  34  show cutting and tool bending after cutting. 
     When cutting is to be performed, the wire W is clamped between opposing holding tools T 8  and T 9 , and a cutting tool T 10  is slid to cut the wire. 
     When the cut portion is to be bent, it is done by using the rotating tool T 2  according to the procedure described with reference to FIGS. 16 and 17. 
     As described above, in two-dimensional forming, since one tool is driven, a fine adjustment on the position of the tool with respect to a wire can be automatically made by using the swing support structure. 
     In three-dimensional forming, press forming, and other kinds of special forming, since two or more tools are simultaneously driven, if a plurality of tools simultaneously swing, some problems may arise. For this reason, some tools may be fixed so as not to swing by removing the bridges  407 . 
     Arrangement of Controller 
     The arrangement of a controller for the spring manufacturing apparatus according to this embodiment will be described next. 
     FIG. 35 is a block diagram showing the arrangement of a controller for the spring manufacturing apparatus. 
     As shown in FIG. 35, a CPU  501  controls the overall controller. A ROM  502  stores processing contents (programs) of the CPU  501  and various font data. A RAM  503  is used as a work area of the CPU  501 . A display unit  504  is used to perform various settings, display the contents of the settings, and also display a manufacturing process and the like in the form of graphs. An external storage device  505  is a floppy disk drive or the like and used to externally supply a program or store various setting contents for wire forming. With this arrangement, for example, by storing parameters for a given forming process (e.g., for a spring, its free length, diameter, and the like) in advance, springs having the same shape can always be manufactured by setting the floppy disk and executing the program. 
     A keyboard  506  is used to set various parameters. Sensors  507  are used to detect the feed amount of wire, the free length of a spring, and the like. 
     Motors  508 - 1  to  508 -n include a motor for driving the wire feed roller pair  320 , a motor for rotating the wire feed roller pair  320  and wire guide  330 , and a motor for driving the swing ring. The motors  508 - 1  to  508 -n are respectively driven by motor drivers  509 - 1  to  509 -n. 
     In this control block, the CPU  501 , for example, independently drives the respective motors, input/output data to/from the external storage device  505 , and controls the display unit  504  in accordance with instructions input through the keyboard  506 . 
     The present invention is not limited to the above embodiments and various changes and modifications can be made within the spirit and scope of the present invention. Therefore, to apprise the public of the scope of the present invention the following claims are made.