JP2012030291A - Spring grinding device, and spring grinding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spring grinding device and a spring grinding method capable of grinding the workpiece of a small lot smaller than a workpiece holding capacity.SOLUTION: According to the coil grinding device 10 and the spring grinding method, when a workpiece 90 is housed in only a part of a plurality of spring housing holes 55, if the workpiece 90 is not located below a movable contact 61, the movable contact 61 is lifted by a contact lifting driving part 64. If the workpiece 90 is located under the movable contact 61, the lifting of the movable contact 61 is stopped to check a length. Thus, even the workpiece 90 of a small lot smaller than a workpiece holding capacity that is the number of spring housing holes 55 is ground.

Description

  The present invention comprises a plurality of spring accommodation holes that are vertically arranged in the outer edge portion of the rotary table arranged in a ring shape, and a part of the rotary table is disposed between the end faces of a pair of rotary grindstones that are vertically opposed to each other. A spring lower end support plate having an upper surface substantially flush with the end surface of the rotating grindstone on the side is disposed below the rotary table, and a compression coil spring is inserted into each spring accommodating hole to rotate the rotary table, thereby compressing the compression coil. The present invention relates to a spring grinding apparatus for grinding both end faces of a spring.

  Conventionally, in this type of spring grinding apparatus, while rotating the rotary table and grinding the compression coil spring group with a pair of rotating grindstones, the movable contact is slidably contacted with the upper surface of the rotating compression coil spring group. The coil length of the compression coil spring is detected, and the control is performed so that the compression coil spring group approaches the target coil length by changing between the pair of rotary tables according to the detection result ( For example, see Patent Document 1).

JP-A-9-201752 (FIGS. 1 and 2, paragraphs [0025] and [0026])

  However, in the conventional spring grinding apparatus, when the rotary table is rotated in a state where the compression coil spring is accommodated only in a part of the spring accommodation hole group and the movable contact is brought into sliding contact with the upper surface of the compression coil spring group, the movable contact is made. When the child faces the empty spring housing hole, it falls to the upper opening edge of the spring housing hole, resulting in a detection abnormality, and even if the coil length of the compression coil spring group does not reach the target value, the spring grinding device Has stopped abnormally. If the rotary table continues to rotate without abnormally stopping the spring grinding device, the movable contact comes into contact with the compression coil spring protruding upward from the upper surface opening accommodated in the spring accommodating hole, and is movable. The contact could be deformed. That is, in the conventional spring grinding apparatus, it was not possible to grind a small number of workpieces smaller than the workpiece holding constant, which is the number of spring accommodating hole groups.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a spring grinding apparatus and a spring grinding method that can grind a small number of workpieces smaller than the workpiece holding constant.

  In order to achieve the above object, a spring grinding apparatus according to the invention of claim 1 is provided with a plurality of spring receiving holes arranged vertically in the outer edge portion of the rotary table, and a pair of rotations opposed to each other vertically. A part of the rotary table is arranged between the end faces of the grindstone, and a spring lower end support plate having an upper surface substantially flush with the end face of the lower rotary grindstone is arranged below the rotary table, and in each spring accommodating hole. Is a spring grinding device for grinding both end faces of the compression coil spring by accommodating the compression coil spring and rotating the rotary table, and is in contact with the upper end surface of the compression coil spring on the side of the upper rotating grindstone. In a spring grinding apparatus for monitoring a coil length, comprising a movable movable contact and a length measuring means for measuring the coil length of a compression coil spring based on the vertical position of the movable contact. From compression coil spring When the compression coil spring is accommodated only in a part of the plurality of spring accommodation holes, the contact pulling means that can be pulled up to a position spaced apart from each other, the table position sensor that detects the rotational position of the rotary table, Based on the position data storage unit for storing the position of the spring accommodation hole in which the compression coil spring is accommodated, the detection result of the table position sensor, and the stored content of the position data storage unit, the compression coil spring is When not arranged below, the contact pulling means lifts the movable contact while the compression coil spring is located below the movable contact, and the contact pulling means It has a feature in that it includes length change switching control means for stopping the pulling and causing the length measuring means to perform length measurement.

  According to a second aspect of the present invention, in the spring grinding apparatus according to the first aspect, the compression coil accommodated in the spring accommodating hole group is defined as the number of exposed spring holes deviating from between the pair of rotating grindstones. When the total number of springs is a continuous arrangement with the number of exposed holes or less, all the compression coil springs are disengaged from between a pair of rotating grindstones, and some compression coil springs are arranged below the movable contacts. A table rotation control means for stopping the rotary table in the state and restarting the rotation of the rotary table after the length measurement by the length measurement means is completed, and the length change control means is provided when the rotation table is stopped by the table rotation control means. The contact pulling means stops the pulling of the movable contact and the length measuring means performs the length measurement, and then the contact pulling means pulls the movable contact.

  According to a third aspect of the present invention, in the spring grinding apparatus according to the first aspect, when the compression coil spring is accommodated in only a part of the plurality of spring accommodation holes, the length change control means rotates the rotary table. And is configured to switch between a state in which the movable contact is lifted by the contact pulling means and a state in which the pulling is stopped.

  According to a fourth aspect of the present invention, in the spring grinding apparatus according to any one of the first to third aspects, at least one of the pair of rotating grindstones is moved in the direction of the rotation axis, and the distance between the pair of rotating grindstones is determined. The grinding wheel linear motion mechanism is provided for changing the distance between the pair of rotary grinding wheels from the initial spacing larger than the coil length before grinding, which is the coil length of the compression coil spring before grinding, before grinding. While the rotary table is rotated so that the compression coil spring passes at least once between the pair of rotating grindstones while being gradually narrowed to the first set interval less than the coil length and greater than or equal to the target coil length, After the interval between the pair of rotating wheels is fixed at the first set interval, the rotary table rotates so that the compression coil spring passes at least once between the pair of rotating wheels, and the length change control means Is the distance between a pair of rotating wheels It is after the fixed interval is fixed, and on the condition that the compression coil spring is disposed below the movable contact, the lifting of the movable contact by the contact pulling means is stopped and the length measuring means is used. It is characterized in that it is configured to perform length measurement.

  According to a fifth aspect of the present invention, in the spring grinding apparatus according to the fourth aspect, the movable range of the movable contact corresponds to the zero point position corresponding to the target coil length of the compression coil spring and the upper limit coil length of the compression coil spring. When the position of the movable contact is higher than the upper limit position, the first comparison result signal is output to the length measuring means, and the position of the movable contact is higher than the 0 point position and lower than the upper limit position. A comparator that outputs a second comparison result signal and outputs a third comparison result signal when the position of the movable contact is 0 position or less is provided. Is output, the interval between the pair of rotating wheels is narrowed. When the comparator outputs the second comparison result signal, the interval between the pair of rotating wheels is fixed at the current interval, and the comparator outputs the third comparison result signal. Output To is characterized at widening the spacing of the grinding wheel of the pair to the initial interval.

  According to a sixth aspect of the present invention, there is provided a spring grinding method comprising a plurality of spring receiving holes arranged vertically in the outer edge portion of the rotary table, arranged in an annular shape, and a rotary table having a pair of rotary grindstones facing each other between the end faces of the rotary table. The spring lower end support plate having an upper surface substantially flush with the end surface of the lower rotating grindstone is disposed below the rotary table, and is further moved up and down in contact with the upper end surface of the compression coil spring. A movable contactor capable of measuring the length of the compression coil spring based on the upper and lower positions of the movable contactor, and a compression coil spring accommodated in each spring accommodation hole. In a spring grinding method using a spring grinding apparatus that grinds both end faces of a compression coil spring by rotating a rotary table and monitors the coil length, the movable contact can be lifted to a position spaced upward from the compression coil spring. Contact When the child coil lifting means is provided and the compression coil spring is accommodated only in a part of the plurality of spring accommodation holes, when the compression coil spring is not disposed below the movable contact, When the compression coil spring is arranged below the movable contact while the movable contact is lifted by the means, the lift by the contact pulling means is stopped and the length is measured by the length measuring means. However, it has the characteristics.

  A seventh aspect of the present invention is the spring grinding method according to the sixth aspect, wherein the number of exposed spring holes is the number of exposed spring holes separated from between the pair of rotating grindstones, and the compression coils are accommodated in the spring accommodating hole group. The total number of springs is set to be equal to or less than the number of exposed holes, and all the compression coil springs are disengaged from a pair of rotating grindstones, and some compression coil springs are disposed below the movable contacts. The rotary table is stopped in a state of being stopped, the lifting of the movable contact by the contact lifting means is stopped, the length is measured by the length measuring means, the movable contact is lifted, and the rotation of the rotary table is resumed. Have

  According to an eighth aspect of the present invention, in the spring grinding method according to the sixth aspect, the compression coil spring is accommodated only in a part of the plurality of spring accommodation holes, and the rotation of the rotary table is maintained and the movable member is movable by the contact pulling means. It is characterized in that it switches between a state in which the contact is pulled up and a state in which the lifting is stopped.

[Inventions of claims 1 to 3 and 6 to 8]
According to the spring grinding apparatus of claim 1 and the spring grinding method of claim 6, the compression coil spring is accommodated in the plurality of spring accommodation holes provided in the rotary table, and the upper and lower ends of the compression coil spring are exposed from the spring accommodation hole. Then, both end surfaces of the compression coil spring can be ground by rotating the rotary table and passing the compression coil spring group between the end surfaces of the pair of rotating grindstones. Further, the coil length can be measured and monitored by bringing the movable contact of the length measuring means into contact with the upper end surface of the ground compression coil spring. Here, in the spring grinding apparatus and the spring grinding method of the present invention, when the compression coil spring is accommodated only in a part of the plurality of spring accommodation holes, the compression coil spring is disposed below the movable contact. When there is not, the movable contact is pulled up by the contact pulling means. When the compression coil spring is arranged below the movable contact, the length of the movable contact is stopped by stopping the lifting of the movable contact by the contact pulling means, so that the number of the spring holding hole groups is maintained. Even a small number of compression coil springs smaller than a constant number can be ground.

  The rotary table may be stopped at every length measurement (inventions of claims 2 and 7), or may continue to rotate during length measurement (inventions of claims 3 and 8). . If the rotary table is stopped each time the length is measured, it is possible to use an inexpensive contact pulling means with low followability. On the other hand, if the rotary table continues to rotate during length measurement, the rotary table is stopped one by one. This eliminates the need for energy efficiency.

[Invention of claim 4]
According to the configuration of the fourth aspect, since the length measurement is performed from the middle of the compression coil spring from the start to the end thereof, the movable contact is possible as compared with the case where the length is measured immediately after the compression coil spring is ground. Wasteful contact between the child and the compression coil spring is reduced, and durability of the movable contact is improved.

[Invention of claim 5]
According to the configuration of claim 5, the zero point position corresponding to the target coil length of the compression coil spring and the upper limit position corresponding to the upper limit coil length of the compression coil spring are set in the movable range of the movable contact, The distance between the pair of rotating wheels is changed or fixed based on whether the position of the movable contact is higher than the upper limit position, between the upper limit position and the zero point position, or below the zero point position. Thus, the compression coil spring can be brought close to the target coil length.

1 is a side view of a spring grinding apparatus according to a first embodiment of the present invention. Front view of spring grinding machine Top view of spring grinding machine Block diagram showing the electrical configuration of the spring grinding machine Conceptual diagram of movable contact and compression coil spring during length measurement Flow chart of control program Flow chart of small lot grinding process Flowchart of small lot grinding processing according to the second embodiment

[First Embodiment]
Hereinafter, a coil grinding apparatus 10 according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the coil grinding apparatus 10 according to the present embodiment includes a frame 11 installed on the floor and a pair of movable base portions 12A and 12B arranged vertically. Between the frame 11 and the upper movable base portion 12A, a linear guide (not shown) extending in the vertical direction and a ball screw mechanism 13A are provided. Then, the ball screw mechanism 13A is actuated by the grindstone lifting / lowering motor 14A, and the movable base portion 12A can be positioned at any upper and lower positions. Similarly, a linear guide and a ball screw mechanism 13B are also provided between the frame 11 and the lower movable base portion 12B, and the movable base portion 12B is positioned at any upper and lower positions by the grindstone lifting / lowering motor 14B. Can be done.

  A sleeve 15A is suspended vertically downward from the upper movable base portion 12A, and a drive shaft (not shown) is rotatably supported inside the sleeve 15A. A rotary grindstone 20A is fixed to the lower end portion of the drive shaft so as to be integrally rotatable, and a grindstone drive motor 16A is connected to the upper end portion of the drive shaft via a pulley and a belt (both not shown). On the other hand, a sleeve 15B extends vertically upward from the lower movable base portion 12B, and a drive shaft (not shown) is rotatably supported inside the sleeve 15B. The rotating grindstone 20B is fixed to the upper end portion of the drive shaft so as to be integrally rotatable, and the grindstone drive motor 16B is connected to the lower end portion of the drive shaft via a pulley and a belt. These rotary grindstones 20A and 20B are both disk-shaped and have the same outer diameter. In addition, the end faces 21A and 21B facing each other of the rotating grindstones 20A and 20B are both flat surfaces orthogonal to the rotation axes J1 and J2 of the rotating grindstones 20A and 20B.

  As shown in FIG. 2, a grinding wheel setting mechanism 30 is provided on the side surface of the frame 11 to maintain the end faces 21A and 21B of the rotating grinding wheels 20A and 20B on a flat surface. The grindstone sharpening mechanism 30 is provided with a pair of sharpening tools 34A and 34B corresponding to the upper and lower rotary grindstones 20A and 20B. The sharpening tool 34A is supported by a bracket 33A that is vertically moved by a tool lifting / lowering motor 32A so as to be horizontally movable, and is horizontally driven linearly by a tool horizontal drive motor 35A. Then, with the upper rotary grindstone 20A being rotationally driven, the sharpening tool 34A moves along the end surface 21A of the upper rotary grindstone 20A, so that the end surface 21A is flattened. Similarly, the sharpening tool 34B is supported by a bracket 33B that is moved up and down by a tool lifting / lowering motor 32B, and is horizontally driven linearly by a tool horizontal drive motor 35B to sharpen the end face 21B of the lower rotating grindstone 20B.

  As shown in FIG. 1, a spring holding and moving mechanism 50 is provided on the front surface of the frame 11. The spring holding and moving mechanism 50 is assembled to a support base 51 that protrudes laterally from the lower part of the frame 11. A table drive shaft (not shown) extending in the vertical direction is rotatably supported on the support base 51, and a rotary table 52 is attached to an upper end portion of the table drive shaft so as to be integrally rotatable. And as shown in FIG. 2, the table drive motor 53 with which the lower end surface of the support stand 51 was equipped is connected with the lower end part of the table drive shaft via the reduction gear 53G. The rotation direction of the rotary table 52 is counterclockwise when viewed from above (see arrow A in FIG. 3). Further, the rotational directions of the rotating grindstones 20A and 20B are both counterclockwise as viewed from above.

  As shown in FIG. 3, a plurality of spring accommodation holes 55 are formed through the outer edge of the turntable 52 in the vertical direction. The spring housing holes 55 are circular, and their center points are arranged at equal intervals on an imaginary circle centered on the rotation center of the turntable 52, and adjacent spring housing holes 55, 55 are arranged. Adjacent. Then, the compression coil spring is accommodated in these spring accommodating holes 55 as a workpiece 90 which is a grinding object of the coil grinding apparatus 10.

  As shown in FIG. 1, a spring lower end support disk 54 is fixedly provided at an upper end portion of the support base 51 facing the rotary table 52 in the vertical direction. The spring lower end support plate 54 is concentric with the rotary table 52 and has a disk shape slightly larger than the rotary table 52. The spring lower end support plate 54 has an arc-shaped notch (not shown) concentric with the rotating grindstone 20B and slightly larger in diameter than the rotating grindstone 20B in order to avoid interference with the lower rotating grindstone 20B. Is provided. When the turntable 52 rotates, the lower end portion of the work 90 group housed in the spring housing hole 55 comes into sliding contact with the upper surface of the spring lower end support board 54.

  The spring lower end support plate 54 is moved up and down with respect to the support base 51 together with the rotating grindstone 20B by driving the grinding wheel lifting / lowering motor 14B, and the upper surface of the spring lower end support plate 54 and the end surface 21B of the lower rotating grindstone 20B Can be made the same.

  Further, the spring lower end support board 54 is provided with a discharge port shutter 58 at a position in the vicinity of the portion that rides on the spring lower end support board 54 that has passed through the inter-grinding wheel region R1. The discharge port shutter 58 is normally closed. When the discharge port shutter 58 is opened, the work 90 is discharged downward from the spring accommodating hole 55.

  As shown in FIG. 2, above the rotary table 52 in the front surface of the frame 11, a door 42 having spring guides 42A and 42B at the lower end is supported so as to be vertically movable with respect to the upper movable base portion 12A. The door lifting / lowering motor 41 is positioned at an arbitrary vertical position. As the rotary table 52 rotates, the workpiece 90 in the spring accommodation hole 55 group is slidably contacted with the spring guide 42A when entering the inter-grinding area R1 from outside the inter-grinding area R1, and is compressed and deformed. When escaping from the inside of R1 to the outside of the inter-grinding wheel region R1, it is expanded and deformed by sliding contact with the spring guide 42B.

  As shown in FIG. 1, a length measuring device 60 is provided on the side of the upper rotating grindstone 20A. Further, the length measuring device 60 is disposed above the spring accommodation hole 55 just before entering the lower part of the spring guide 42A by rotating out of the group of spring accommodation holes 55 deviated from the inter-grinding wheel region R1 (see FIG. 2). (See FIG. 3). Further, as shown in FIG. 2, the length measuring device 60 has a structure in which the movable contact 61 is supported by the sensor main body 62 so as to be linearly movable in the vertical direction. The lower end of the movable contact 61 is provided with a flat plate 61A larger than the outer diameter of the work 90 accommodated in the spring accommodating hole 55, and between the flat plate 61A and the lower end surface of the sensor main body 62. A lowering biasing spring 63 (see FIG. 1) for biasing the movable contact 61 downward is provided.

  The sensor main body 62 includes an output circuit 66 (see FIG. 4) and a contact pulling up drive unit 64 for pulling up and holding the movable contact 61 (see FIG. 2). For example). The output circuit 66 outputs the position of the movable contact 61 in the vertical direction as a contact position detection signal. The contactor position detection signal is a digital signal, for example, and is set to increase as the position of the movable contactor 61 increases.

  The contact pull-up drive unit 64 is an air cylinder, and the hook provided on the linear rod (not shown) of the contact pull-up drive unit 64 is pulled up from below by the hook provided at the upper end of the movable contact 61. Thus, the movable contact 61 is lifted and held at a position spaced upward from the workpiece 90. Further, when releasing (stopping) the lifting, the hook of the direct acting rod of the contact pull-up drive unit 64 is lowered below the hook of the movable contact 61. As a result, the movable contact 61 can move up and down without being affected by the contact pull-up drive unit 64. Further, the contact pull-up drive unit 64 changes the portion that receives the compressed air by switching the electromagnetic valve 64V shown in FIG. 4, and lifts the movable contact 61 and releases it as described above. Switch to state.

  The above-described grinding wheel lifting / lowering motors 14A and 14B, grinding wheel driving motors 16A and 16B, table driving motor 53, tool lifting / lowering motors 32A and 32B, tool horizontal driving motors 35A and 35B, and door lifting / lowering motor 41 are all servo motors. And position detection sensors 14E1, 14E2, 16E1, 16E2, 53E (for example, encoders or resolvers) for rotating the position of the output shaft. These servo motors are driven and controlled by the controller 70 shown in FIG. Note that FIG. 4 shows only a portion of the control target of the controller 70 that is deeply related to the present invention. Further, the position detection sensor 53E provided in the table drive motor 53 corresponds to the “table position sensor” according to the present invention. The initial position at the rotational position of the rotary table 52 is stored in the memory 72 described below as detection data of the position detection sensor 53E.

  The controller 70 includes a CPU 71, a memory 72 (corresponding to the “position data storage unit” of the present invention), a valve drive for driving the servo amplifier 74 group for the servo motor group and the contact pull-up drive unit 64 described above. A circuit 76 is provided. Then, the CPU 71 executes the control program PG1 (see FIG. 6) stored in the memory 72 and outputs a command value to the servo amplifier 74 group and the valve drive circuit 76 to control the drive of the servo motor group, The upper drive unit 64 switches between a state where the movable contact 61 is lifted and a state where the lifting is stopped.

  In addition, the controller 70 is provided with a comparator 75 that compares the contactor position detection signal H from the length measuring device 60 with a preset 0 point position set value Hc and an upper limit position set value Hj. The comparator 75 is configured by the CPU 71 executing a predetermined program stored in the memory 72, and is a comparator on software.

  The 0-point position setting value Hc described above is a contactor position detection signal output from the length detector 60 when the movable contactor 61 comes into contact with the workpiece 90 having a target coil length (coil length as designed). The value of H is set. The upper limit position setting value Hj is set to the value of the contactor position detection signal H output from the length detector 60 when the movable contactor 61 comes into contact with the workpiece 90 having the maximum coil length within the design allowable error range. Has been. The comparator 75 outputs the first determination result when the actual contactor position detection signal H is larger than the upper limit position set value Hj. Further, the comparator 75 outputs the second determination result when the actual contactor position detection signal H is larger than the zero point position set value Hc and not more than the upper limit position set value Hj. Further, the comparator 75 outputs the third determination result when the actual contactor position detection signal H is equal to or less than the zero point position set value Hc.

  The controller 70 includes a console 73 (keyboard or the like) and a monitor 77, and various setting values can be input / changed on the console 73 while being visually recognized on the monitor 77.

  The description regarding the structure of the coil grinding apparatus 10 of this embodiment is above. Next, the operation of the coil grinding apparatus 10 will be described together with the description of the control program PG1 executed by the CPU 71. The control program PG1 is shown in FIG. When the control program PG1 is executed, the master piece setting process (S10) is executed, and the production of the master piece and the input of master data are required. The master piece is a workpiece 90 (compression coil spring) having a coil length (target coil length) as designed, and is manufactured semi-manually from the compression coil spring that is the workpiece 90. Specifically, the rotational speed of the rotary grindstones 20A and 20B, the rotational speed of the rotary table 52, and the unit lowering amount of the upper rotary grindstone 20A are set, and the rotary table 52 is placed at the initial position. The work 90 for making a master piece is accommodated in an arbitrary spring accommodating hole 55 not positioned below, and the coil grinding apparatus 10 is activated. Then, the routine of lowering by the unit lowering amount of the upper rotating grindstone 20A and stopping after rotating the rotary table 52 once is repeatedly executed.

  At this time, the operator appropriately pushes a primary stop button provided on the console 73 of the controller 70 to take out the workpiece 90 from the spring accommodation hole 55 and performs length measurement using, for example, a caliper. The above routine is repeated until the length measurement result is the coil length as designed. When the inspection result is the coil length as designed, the master piece is completed.

  In order to perform “input of master data”, the master piece may be accommodated in the arbitrary spring accommodating hole 55 and manually disposed below the length measuring device 60, and reset operation may be performed on the console 73. Then, the CPU 71 releases the lifting of the movable contact 61 by the contact pull-up drive unit 64, makes the movable contact 61 abut on the upper surface of the master piece, and acquires the contact position detection signal H from the length measuring device 60. Then, the value of the contactor position detection signal H at that time is set to the above-described 0-point position set value Hc.

  Further, the CPU 71 detects a position above the position of the upper rotating grindstone 20A when the master piece is completed by a predetermined amount (for example, 1 [mm]) as a set value for controlling the height of the upper rotating grindstone 20A. A long start position P3 (see FIG. 5) is set, and a position above the length measurement start position P3 by a predetermined amount (for example, 0.3 [mm]) is set as a grindstone lowering speed switching position P2 (see FIG. 5). Then, the process exits from the master piece setting process (S10). Here, when the upper rotating grindstone 20A is arranged at the length measurement start position P3, the length measurement result of the workpiece 90 is detected so as to reach the 0-point position set value Hc after a certain period of time by so-called spark-out grinding. The long start position P3 is set.

  As shown in FIG. 6, when the master piece setting process (S10) is exited, a grinding condition setting process (S11) is executed. When the grinding condition setting process (S11) is executed, an input of an allowable error of the designed coil length is obtained on the monitor 77. When the allowable error is input, the CPU 71 sets the above-described 0-point position setting value. The value of the contactor position detection signal H when the movable contactor 61 is positioned upward by an allowable error (for example, 0.8 [mm]) is calculated by Hc, and this value is calculated as the upper limit position setting value Hj described above. Set to.

  Next, the grinding start position P1 (see FIG. 5), the high speed descent speed, the medium speed descent speed and the unit descent amount of the upper rotating whetstone 20A, the rotating speed of the rotating whetstones 20A and 20B, and the rotating speed of the rotary table 52 are determined. Confirmation of each set value and change as necessary are required. If there is no need to change, the confirmation button of the console 73 is operated. Operate the button. Then, the grinding condition setting process (S11) is skipped, and as shown in FIG. 6, it is asked whether or not the grinding is performed in the normal mode (S12). Here, the operator selects the normal mode when the workpiece 90 is accommodated in all the spring accommodation holes 55 of the turntable 52 and grinding is performed (YES in S12), and only a part of the group of the spring accommodation holes 55 is selected. When the workpiece 90 is accommodated in the grinding, a mode that is not the normal mode selection, that is, the small lot mode is selected (NO in S12).

  When the small lot mode is selected (NO in S12), the small lot grinding process (S13) is executed. As shown in FIG. 7, in the small lot grinding process (S13), a work accommodation position setting process (S20) is first executed, and the position of the spring accommodation hole 55 in which the work 90 is accommodated is obtained. Therefore, the operator operates the console 73 to move the rotary table 52 to the initial position, and the spring accommodating hole 55 located below the length measuring device 60 (hereinafter, the spring located below the length measuring device 60 at the initial position). The housing hole 55 is referred to as “leading spring housing hole 55”), and the workpiece 90 is housed in order from the leading spring housing hole 55 to the spring housing hole 55 on the rear side in the rotation direction of the rotary table 52. . Here, assuming that the number of spring accommodation holes that are out of the inter-grinding wheel region R1 is the number of exposed holes, the number of workpieces 90 accommodated in the spring accommodation holes 55 is set to be equal to or less than the number of exposed holes. When the number of workpieces 90 to be ground is greater than the number of exposed holes, grinding may be performed in two batches in a small lot mode. When the workpieces 90 are accommodated in the spring accommodation holes 55, the number of the spring accommodation holes 55 in which the workpieces 90 are accommodated is input through the console 73.

  As a result, the workpiece receiving position setting process (S20) is exited, and the lengthless grinding process (S30) is executed. When the lengthless grinding process (S30) is executed, grinding is performed with the contact pull-up driving unit 64 pulling up the movable contact 61. Specifically, the CPU 71 lowers the upper rotating grindstone 20A from the grinding start position P1 shown in FIG. 5 to the grindstone descent speed switching position P2 at a high descent speed, during which the turntable 52 has a designated rotation speed. Rotate at a constant speed. Thereby, the workpiece | work 90 group passes between the area | region R1 between grindstones in multiple times, and the upper and lower both end surfaces of the workpiece | work 90 are ground by rotary grindstone 20A, 20B. When the upper rotating grindstone 20A reaches the grindstone descent speed switching position P2, the descent speed is changed from the high speed descent speed to the medium speed descent speed, and length measurement of the upper rotating whetstone 20A is started from the grindstone descent speed switching position P2. The rotary table 52 continues to rotate at a constant speed during the period of lowering to the position P3. Thereby, the work 90 group is further ground.

  When the upper rotating grindstone 20A reaches the length measurement start position P3, the grinding process without length measurement (S30) is completed, and then the grinding process with length measurement (S40) is executed. When the grinding process with length measurement (S40) is executed, the CPU 71 stops the rotary table 52 at the initial position (S41). Thereby, all the workpiece | work 90 will remove | deviate from the area | region R1 between grindstones, and it will be in the state by which grinding was interrupted. Then, the CPU 71 releases the lifting of the movable contact 61 by the contact pull-up drive unit 64 (S42). Then, the movable contact 61 is brought into contact with the workpiece 90 accommodated in the leading spring accommodating hole 55, and the contact position detection signal H output from the output circuit 66 of the length measuring device 60 at that time is taken into the CPU 71 (S43). ). Thereafter, the CPU 61 lifts the movable contact 61 (S44).

  Next, the CPU 71 determines whether or not the contactor position detection signal H is larger than the upper limit position set value Hj, that is, whether or not the output of the comparator 75 is the first determination result (S45), and the contactor position detection signal. If H is not greater than the upper limit position set value Hj (NO in S45), whether or not the contactor position detection signal H is equal to or less than the upper limit position set value Hj and greater than the zero point position set value Hc, that is, the comparator 75. It is determined whether or not the output is the second determination result (S46).

  In the present embodiment, the CPU 71 and the length measuring device 60 when executing the above steps S43, S45, and S46 correspond to the “length measuring means” of the present invention. Further, the CPU 71 when executing the above-described steps S42 and S44 corresponds to the “length measuring switching means” of the present invention. Furthermore, the CPU 71 when executing step S41 and step S48 described later corresponds to the “table rotation control means” of the present invention.

  At this time, if the contactor position detection signal H is larger than the upper limit position set value Hj (YES in S45), the upper rotating grindstone 20A is lowered by the descending unit amount (S47), and then the rotary table 52 is moved a predetermined number of times. (S48), the workpiece 90 group is additionally ground, and operations such as taking in the contactor position detection signal H again are repeated (S41 to S44).

  If the contactor position detection signal H is equal to or lower than the upper limit position set value Hj and greater than the 0-point position set value Hc (NO in S45, YES in S46), the upper rotating grindstone 20A is held at the current position. Then, the rotary table 52 is rotated a predetermined number of times (S48), the workpiece 90 group is additionally ground, and operations such as taking in the contactor position detection signal H again are repeated (S41 to S44).

  When the contactor position detection signal H is equal to or less than the zero point position set value Hc (NO in S45, NO in S46), the coil length of the workpiece 90 matches the target coil length within an allowable error range. Judgment is made and the process exits from the grinding process with length inspection (S40). Then, the upper rotating grindstone 20A is raised (S49), and the discharge port shutter 58 is opened and the rotary table 52 is rotated to discharge the work 90 group from the spring accommodation hole 55 to a predetermined work accommodation box (S50). The small lot grinding process (S13) and the control program PG1 are exited.

  When the above-described normal mode is selected (YES in S12), the normal grinding process (S14) is executed. Then, a feeder (not shown) accommodates the workpiece 90 in all the spring accommodation holes 55, and performs the same lengthless grinding process (S30) as the above-described small lot grinding process (S13). Thereafter, the rotation of the rotary table 52 is maintained, the lifting of the movable contact 61 by the contact pull-up drive unit 64 is released, and the movable contact 61 is brought into sliding contact with the workpiece 90 group to perform length measurement. Then, the contact position detection signal H of the comparator 75 is the same as in the small lot grinding process (S13) except that the rotary table 52 is continuously rotated and the movable contact 61 is kept in sliding contact with the workpiece 90 group. Grinding is performed until 0 becomes the 0 point position set value Hc or less, and when the 0 point position set value Hc or less, the workpiece 90 group is discharged.

  As described above, according to the coil grinding apparatus 10 and the spring grinding method of the present embodiment, when the workpiece 90 is accommodated only in a part of the plurality of spring accommodation holes 55, the workpiece 90 is connected to the movable contact 61. If it is not arranged below, the movable contact 61 is pulled up by the contact pull-up drive unit 64, and when the work 90 is arranged below the movable contact 61, the lifting of the movable contact 61 is stopped. Since the length is increased, it is possible to grind even a small number of workpieces 90 smaller than the workpiece holding constant, which is the number of the spring accommodation holes 55 group. Further, since the rotary table 52 is stopped every time the length is measured, it is possible to use an inexpensive contact pull-up drive unit 64 with low followability. Furthermore, since the length measurement is performed from the middle of the work 90 until the end of grinding, the movable contact 61 and the work 90 are useless compared to the case where the length is measured immediately after the grinding of the work 90 is started. The contact is reduced and the durability of the movable contact 61 is improved.

[Second Embodiment]
This embodiment is mainly different from the first embodiment in that step S51 for determining whether or not the rotary table 52 has passed the initial position is provided instead of step S41 of the grinding process with length measurement (S40) in the first embodiment. . Then, the CPU 71 determines that the rotary table 52 is at the initial position and the leading work 90 is positioned below the movable contact 61 based on the rotational speed of the rotary table 52 and the total number of the workpieces 90 accommodated in the spring accommodating holes 55. After that, the time required until the last work 90 is positioned below the movable contact 61 is calculated, and when the rotary table 52 passes through the initial position (YES in S51), the required time described above from the passing timing. Until the time elapses, the lifting of the movable contact 61 is canceled (S42), the contact position detection signal H is taken in (S43), and the process of lifting the movable contact 61 is performed again (S44). . Accordingly, similarly to the first embodiment, it is possible to grind even a small number of workpieces 90 smaller than the workpiece holding constant, which is the number of the spring accommodation holes 55 group. In the first embodiment, when the number of workpieces 90 is larger than the number of exposed holes, it is necessary to perform grinding by dividing the workpiece 90 into two times less than the number of exposed holes. More than 90 workpieces 90 can be ground at a time. In addition, since the rotary table 52 is not stopped each time the length is measured, energy efficiency is good.

[Other Embodiments]
The present invention is not limited to the embodiments. For example, the embodiments described below are also included in the technical scope of the present invention, and various modifications other than those described below can be made without departing from the scope of the invention. Can be implemented.

(1) Although the coil grinding apparatus 10 of the first embodiment includes the software comparator 75, the coil grinding apparatus 10 may include a comparator circuit.

(2) In the first embodiment, the contact pull-up drive unit 64 is an air cylinder, but may be a solenoid or a motor.

(3) In the first embodiment, an identification mark corresponding to each spring accommodation hole 55 may be attached to the upper surface of the turntable 52. When the input of the position of the spring accommodation hole 55 in which the workpiece 90 is accommodated is requested in the workpiece accommodation position setting process (S20), the identification mark of the spring accommodation hole 55 in which the workpiece 90 is accommodated. May be input on the console 73.

DESCRIPTION OF SYMBOLS 10 Coil grinding apparatus 11 Frame 20A, 20B Rotary grindstone 52 Rotary table 54 Lower end support board 60 Length detector 61 Movable contactor 64 Contactor raising drive part (contactor raising means)
71 CPU
72 Memory (position data storage unit)
75 Comparator 90 Workpiece (Compression coil spring)
H Contact position detection signal Hc 0 point position set value Hj Upper limit position set value P1 Grinding start position P2 Grinding wheel lowering speed switching position P3 Length measuring start position PG1 Control program

Claims (8)

A plurality of spring accommodation holes penetrating up and down at the outer edge of the turntable are arranged in a ring shape, and a part of the turntable is disposed between the end faces of a pair of rotating whetstones facing up and down. A spring lower end support plate having an upper surface substantially flush with the end surface of the rotating grindstone is disposed below the rotary table, and a compression coil spring is accommodated in each of the spring accommodating holes to rotate the rotary table. A spring grinding device for grinding both end faces of a compression coil spring,
A movable contact that can move up and down by contacting the upper end surface of the compression coil spring on the side of the upper rotating grindstone, and the coil length of the compression coil spring is measured based on the vertical position of the movable contact. In a spring grinding apparatus comprising a length measuring means for monitoring the coil length,
Contact lifting means capable of lifting the movable contact to a position spaced upward from the compression coil spring;
A table position sensor for detecting a rotational position of the rotary table;
A position data storage unit for storing a position of the spring accommodating hole in which the compression coil spring is accommodated when the compression coil spring is accommodated only in a part of the plurality of spring accommodating holes;
Based on the detection result of the table position sensor and the stored contents of the position data storage unit, when the compression coil spring is not disposed below the movable contact, the movable contact is placed on the contact pulling means. When the compression coil spring is disposed below the movable contact, the length-measuring means performs length measurement by causing the contact-lifting means to stop lifting the movable contact. A spring grinding apparatus comprising: a length changeover control means for controlling the length. When the number of the spring accommodation holes separated from between the pair of rotating grindstones is the number of exposed holes, the total number of the compression coil springs accommodated in the spring accommodation hole group is continuously arranged below the number of exposed holes. When all of the compression coil springs are disengaged from between the pair of rotating grindstones and a part of the compression coil springs are arranged below the movable contacts, the rotary table is stopped. A table rotation control means for restarting the rotation of the rotary table after the length measurement by the length measurement means is completed,
The length switching control means causes the contact lifting means to stop lifting the movable contact and performs length measurement to the length measuring means when the rotary table is stopped by the table rotation control means. 2. The spring grinding apparatus according to claim 1, wherein the movable contact is lifted by the contact pulling means.   When the compression coil spring is accommodated only in a part of the plurality of spring accommodation holes, the length changeover control means maintains the rotation of the rotary table and the movable contact by the contact pulling means. 2. The spring grinding apparatus according to claim 1, wherein the spring grinding apparatus is configured to switch between a state in which the child is pulled up and a state in which the lifting is stopped. A grindstone linear movement mechanism for moving at least one of the pair of rotating grindstones in the rotation axis direction to change the interval between the pair of rotating grindstones,
The grindstone linear movement mechanism sets the interval between the pair of rotating grindstones from an initial interval larger than a coil length before grinding, which is a coil length of the compression coil spring before grinding, to be less than the coil length before grinding and greater than or equal to the target coil length. The rotary table is rotated so that the compression coil spring passes at least once between the pair of rotating grindstones while being gradually narrowed to the first set interval, and the pair of rotations is performed. After the grindstone interval is fixed at the first set interval, the rotary table is rotated so that the compression coil spring passes at least once between the pair of rotating grindstones,
The length detection switching control means is that the interval between the pair of rotating grindstones is fixed at the first set interval, and the compression coil spring is disposed below the movable contact. 4. The apparatus according to claim 1, wherein the length of the movable contact is stopped by the contact pulling means and the length measuring means is made to perform length measurement on the condition of the above. The spring grinding apparatus according to Item. In the movable range of the movable contact, a zero point position corresponding to the target coil length of the compression coil spring and an upper limit position corresponding to the upper limit coil length of the compression coil spring are set,
The length measuring means outputs a first comparison result signal when the position of the movable contact is higher than the upper limit position, and when the position of the movable contact is higher than the zero point position and lower than the upper limit position. A comparator is provided that outputs a second comparison result signal and outputs a third comparison result signal when the position of the movable contact is equal to or less than the zero point position;
When the comparator outputs the first comparison result signal, the grindstone linear motion mechanism narrows the interval between the pair of rotating grindstones, and when the comparator outputs the second comparison result signal, the pair of rotation grindstones The interval between the rotating grindstones is fixed to the current interval, and when the comparator outputs the third comparison result signal, the interval between the pair of rotating grindstones is increased to the initial interval. Spring grinding equipment. A plurality of spring accommodation holes penetrating up and down at the outer edge of the turntable are arranged in a ring shape, and a part of the turntable is disposed between the end faces of a pair of rotating whetstones facing up and down. A spring lower end support plate having an upper surface substantially flush with the end surface of the rotating grindstone is disposed below the rotary table, and further, a movable contactor that can move up and down in contact with the upper end surface of the compression coil spring, Length measuring means for measuring the coil length of the compression coil spring based on the vertical position of the movable contact is provided, the compression coil spring is accommodated in each spring accommodation hole, and the rotary table is rotated. In the spring grinding method using a spring grinding apparatus that grinds both end faces of the compression coil spring and monitors the coil length,
A contact pulling means capable of pulling the movable contact to a position spaced upward from the compression coil spring;
In a case where the compression coil spring is accommodated only in a part of the plurality of spring accommodation holes and the compression coil spring is not disposed below the movable contact, the movable by the contact pulling means is performed. While the pulling up of the contactor is continued, when the compression coil spring is disposed below the movable contactor, the lifting of the movable contactor by the contactor lifting means is stopped and the length measurement by the lengthening means is performed. A spring grinding method characterized in that: Assuming that the number of the spring accommodation holes separated from between the pair of rotating grindstones is the number of exposed holes, the total number of the compression coil springs accommodated in the group of spring accommodation holes is set to be equal to or less than the number of exposed holes. Arranged in line,
All the compression coil springs are detached from between the pair of rotating grindstones, and a part of the compression coil springs are arranged below the movable contact, and the rotary table is stopped to lift the contact. The spring according to claim 6, wherein lifting of the movable contact by means is stopped and length measurement is performed by the length measuring means, and then the movable contact is lifted and rotation of the rotary table is resumed. Grinding method.   The compression coil spring is accommodated only in a part of the plurality of spring accommodation holes, the rotation of the rotary table is maintained, and the movable contact is lifted by the contact pulling means and the lift is stopped The spring grinding method according to claim 6, wherein the method is switched to.

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