JP2005195484A - Pin diameter measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pin diameter measuring apparatus capable of preventing the contact between a measuring head and a grinding stone and making the measuring head follow a cylindrical work rotating on an axis of rotation through the use of a simple mechanism. <P>SOLUTION: The pin diameter measuring apparatus 10 has the planar quad joint link mechanism 15 comprising a fixed arm 11 fixed to a tool box 82 which moves in a cutting direction; a movable arm 12 which moves in parallel with the fixed arm 11; and two parallel connecting arms 13 and 13 each connected to the fixed arm 11 and the movable arm 12 via fulcrum members 14. The measuring head 17 for measuring the diameter of the work 55 is held by the planar quad joint link mechanism 15. It is thereby possible to make the measuring head 17 follow the cylindrical work 55 rotating on the axis C of rotation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a measuring device for measuring the diameter of a workpiece, and in particular, a pin that is incorporated in a grinding machine or the like and measures the diameter of a cylindrical workpiece that is processed while turning around a rotation axis such as a pin of a crankshaft. The present invention relates to a diameter measuring device.

  When grinding the crankshaft pins, the crankshaft is rotated around the journal axis of the crankshaft on the worktable of the grinding machine, and the grinding wheel that rotates on the grinding wheel base is adjusted to the turning motion of the crankpin. Move forward and backward.

  When measuring the diameter of this crankpin, the crankpin pivots around the axis of rotation, so it cannot be measured during processing with a normal outer diameter measuring device, and processing was temporarily suspended and stopped. Measurement was performed in a state.

  For this reason, there is not only a problem that the processing time is extended, but also a problem that it is not possible to perform automatic sizing processing in which processing is terminated by a sizing signal during processing.

In order to solve such a problem, a measuring machine has been proposed in which a measuring head is attached to a two-joint robot arm provided on a grindstone table so that the measuring head follows the movement trajectory of the crankpin (for example, (See Patent Document 1 or Patent Document 2.)
Japanese National Patent Publication No. 11-513317 JP 2001-225266 A

  However, in the prior art described in the above-mentioned Patent Document 1 (Japanese Patent Publication No. 11-513317), the movement stroke of the crank pin that rotates is covered in order to make the measurement head follow the movement locus of the crank pin. The measurement head is caused to follow the movement locus of the crank pin while the guide portion is in contact with the crank pin.

  For this reason, a large guide member is required, and the measurement head has a large change in posture and a measurement error is likely to occur, and there is a possibility that an accident such as the measurement head or the large guide member coming into contact with the grindstone may occur. Was.

  Further, in the conventional technique described in the above-mentioned Patent Document 2 (Japanese Patent Laid-Open No. 2001-225266), a complicated mechanism is used instead of a large guide member in order to cause the measuring head to follow the movement locus of the crankpin. A limiting device is provided.

  However, this limiting device requires a complicated adjustment to cause the measuring head to follow the movement trajectory of the crankpin while preventing the measuring head from coming into contact with the grindstone, which is a problem in practice. Further, the problem of measurement error due to the change in posture of the measurement head has not been solved.

  The present invention has been made in view of such circumstances, and it is possible to prevent the measurement head from contacting the grindstone and to make the measurement head follow a cylindrical workpiece that pivots around a rotation axis. An object of the present invention is to provide a pin diameter measuring device using a mechanism.

  In order to achieve the above object, the present invention provides a pin diameter measuring device that measures the diameter of a cylindrical workpiece that is processed while turning around a rotation axis, and is fixed to a tool post that moves in a cutting direction. A planar four-bar linkage mechanism comprising: an arm, a movable arm that moves in parallel with the fixed arm, and two connecting arms that are connected to the fixed arm and the movable arm at respective rotation fulcrums, and are parallel to each other; It has a measuring head which is held by a flat four-bar linkage mechanism and follows the turning motion of the workpiece while being in contact with the workpiece, and measures the diameter of the workpiece.

  According to the present invention, since the measuring head for measuring the workpiece diameter is held by the flat four-bar linkage mechanism, the measuring head can be moved along the outer periphery of the grindstone while maintaining a constant posture. With this mechanism, it is possible to prevent the measurement head from contacting the grindstone and to cause the measurement head to follow a cylindrical workpiece that revolves around the rotation axis. In addition, it is possible to prevent measurement errors from occurring due to changes in the posture of the measurement head.

  The present invention also provides a link driving means for driving the planar four-bar linkage mechanism, a guide member attached to the tip of the movable arm and contacting the workpiece, and a holder swingably attached to the movable arm. An arm and a holder arm driving means for swinging the holder arm with respect to the movable arm, the measurement head is attached to the holder arm, and the guide member or the measurement head is in contact with the workpiece Further, it is an additional requirement that it is configured to be able to follow the turning motion of the workpiece.

  According to this additional requirement, it is possible to follow the turning movement of the workpiece while keeping the guide member or the measurement head in contact with the workpiece, so that the measurement head is applied to the workpiece only during measurement while following the workpiece with the guide member. The diameter of the workpiece can be measured by contact. For this reason, wear of the measuring head can be suppressed.

  Further, the tool provided on the tool post is a grinding wheel, and the link length (distance between rotation fulcrums) of the connecting arm is equal to the distance from the end of the guide member to the rotation center of the grinding wheel. Requirements.

  According to this, when the guide member or the measurement head follows the turning motion of the workpiece while being in contact with the workpiece, the distance from the end of the guide member to the center of rotation of the grinding wheel is kept constant, and the guide member is Since it moves along the outer periphery, it is possible to prevent an accident such that the guide member contacts the grindstone.

  Further, according to the present invention, the measurement head includes a reference V base and a displacement detector, and when the reference V base contacts the work, the contact of the guide member with the work is released. Requirements.

  According to this, since the guide member that has been in contact with the workpiece and followed the turning motion of the workpiece escapes from the contact surface with the workpiece by bringing the reference V base of the measuring head into contact with the workpiece when measuring the workpiece, Three-point contact with the workpiece is made by the reference V base and the displacement detector, and the displacement of the workpiece diameter can be accurately measured.

  As described above, according to the pin diameter measuring apparatus of the present invention, since the measuring head for measuring the workpiece diameter is held by the planar four-bar linkage mechanism, the measuring head maintains the constant posture and the outer circumference of the grindstone. The measuring head can be made to follow the cylindrical workpiece that pivots about the rotation axis while preventing the contact between the measuring head and the grindstone with a simple mechanism.

  Hereinafter, preferred embodiments of a pin diameter measuring apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same number or symbol is attached to the same member.

  FIG. 1 is a side view showing a pin diameter measuring apparatus according to the present invention. The pin diameter measuring apparatus 10 is attached via a column 83 to a grinding machine 80 having a grinding wheel base (tool post) 82 that moves in a lateral direction (cutting direction) along a guide rail 81. A grinding wheel (blade) 84 is attached to the grinding wheel base 82 and is driven to rotate by a motor (not shown).

  The pin diameter measuring apparatus 10 includes a fixed arm 11 attached to the column 83 in the vertical direction, a movable arm 12 arranged in parallel to the fixed arm 11, and a fulcrum member (rotating fulcrum) for each of the fixed arm 11 and the movable arm 12. ) A flat four-bar linkage mechanism 15 comprising two connecting arms 13 and 13 connected in parallel with each other, an extension arm 12A attached to the tip of the movable arm 12, and a guide member provided at the tip of the extension arm 12A 18, a holder arm 16 swingably attached to the movable arm 12, a measurement head 17 provided at the tip of the holder arm 16, and the like.

  The link arm length (link length, distance between rotation fulcrums at both ends) L of the connecting arm 13 is equal to the distance from the tip of the guide member 18 to the rotation center of the grinding wheel 84, and is slightly larger than the radius of the grinding wheel 84. Thus, the guide member 18 is prevented from contacting the grinding wheel 84. Note that the length of the connecting arm 13 may be adjustable, and the link arm length L may be adjusted in accordance with a change in the diameter of the grinding wheel 84.

  The fixed arm 11 and one of the two connecting arms 13 and 13 are connected by an air cylinder 21 which is a link driving means. That is, the base of the air cylinder 21 is rotatably attached to the fixed arm 11, and the tip of the shaft 21 </ b> A of the air cylinder 21 is rotatably connected to the connecting arm 13. Accordingly, the planar four-bar linkage mechanism 15 is driven by the expansion and contraction of the shaft 21 </ b> A, and the movable arm 12 moves up and down while maintaining parallel with the fixed arm 11.

  Further, the movable arm 12 and the holder arm 16 are connected by an air cylinder 22 which is a holder arm driving means. That is, the air cylinder 22 is rotatably attached to the fixed arm 11, and the tip of the shaft 22 </ b> A of the air cylinder 22 is rotatably connected to the holder arm 16. Accordingly, the holder arm 16 swings around the connecting portion with the movable arm 12 by the expansion and contraction of the shaft 22A.

  The measuring head 17 provided at the tip of the holder arm 16 includes a reference V base 19 having a V groove that contacts the cylindrical workpiece 55, and a displacement detector 20 attached to the bottom of the V groove of the reference V base 19. It is configured. As the displacement detector 20, a plunger-type optical linear detector capable of detecting a long displacement is used.

  The displacement detector 20 is not limited to a plunger-type optical linear detector, and various known detectors can be used as long as they can detect the displacement of the diameter of the workpiece 55.

  The V angle of the V groove of the reference V table 19 was 60 °. When the V angle is 60 °, a change in workpiece diameter can be detected by the displacement detector 20 as a 1: 1 displacement. However, the V angle is not limited to 60 °, and for example, the measurement range may be widened by making it larger than 60 °.

  As shown in FIG. 2, the guide member 18 provided at the distal end of the extension arm 12 </ b> A has a contact plate 18 </ b> A made of wear-resistant ceramics attached to a contact portion with the work 55. As shown in FIG. 2, when the V groove of the reference V base 19 is brought into contact with the workpiece 55 in order to measure the diameter of the workpiece 55 with the measuring head 17, the displacement detector 20 contacts the workpiece 55. The vertical distance H from the point to the lower surface of the contact plate 18A is configured to be slightly (+ α) larger than the radius R of the workpiece 55, and has a relationship of H = R + α.

  Accordingly, the contact plate 18A that is in contact with the workpiece 55 automatically escapes from the workpiece 55 when the diameter of the workpiece 55 is measured by the measuring head 17, and does not adversely affect the measurement.

  FIG. 3 is a conceptual diagram for explaining the grinding process of the crank pin measured by the pin diameter measuring apparatus of the present invention, FIG. 3 (a) is a front view, and FIG. 3 (b) is a side view.

  As shown in FIG. 3A, the crankshaft 50 is provided with a plurality of pairs of crank webs 54 connected by crankpins (workpieces) 55 between a front shaft 51 and a rear flange 52. Connected by a journal 53.

  When the crankpin 55 of the crankshaft 50 is ground, the crankshaft 50 is rotated about the axis (rotation axis) C of the journal 53. As the crankshaft 50 rotates, the crankpin 55 rotates around the axis C.

  Following the turning motion of the crankpin 55, the grinding wheel 84 reciprocates in the lateral direction while applying a slight infeed as shown in FIG. 3 (b). That is, when the crankpin 55 is positioned at the upper part of the figure (indicated by the dotted line), the grinding wheel 84 is positioned at the position indicated by the solid line in the figure, and as the crankpin 55 turns clockwise, It moves reciprocally between the two positions represented by the two-dot chain line with a slight cutting feed.

  In this way, the crank pin 55 is ground by the lateral movement of the grinding wheel 84 following the turning motion of the crank pin 55. The relative movement relationship of the crankpin 55 with respect to the grinding wheel 84 in this case is as shown in FIG. That is, the crankpin 55 reciprocates up and down relatively along the outer periphery of the grinding wheel 84.

  In FIG. 4, the air cylinder 21 and the air cylinder 22 are operated, and the guide member 18 and the measurement head 17 are positioned at a position where they escape from the crank pin 55 that is a workpiece.

  Next, the operation of the pin diameter measuring apparatus 10 configured as described above will be described. First, as shown in FIG. 4, the air cylinder 21 and the air cylinder 22 are operated, and the grinding process is started in a state where the guide member 18 and the measuring head 17 have escaped from the crankpin 55.

  Next, the air supply of the air cylinder 21 is gradually reduced, and the guide member 18 gradually falls due to the weight of the planar four-bar linkage mechanism 15 and comes into contact with the crankpin 55 to follow the turning motion of the crankpin 55. At this time, the guide member 18 reciprocates up and down along a track along the outer periphery of the grinding wheel 84.

  FIG. 5 shows a state in which the air cylinder 22 is activated and the measuring head 17 has escaped from the crankpin 55, and the guide member 18 comes into contact with the crankpin 55 due to the weight of the planar four-bar linkage mechanism 15, and the crankpin being ground is processed. It shows a state of following the 55 turning motion.

  Grinding is started in a state where the guide member 18 has escaped from the crankpin 55, and then the guide member 18 is brought into contact with the crankpin 55, but from the state in which the guide member 18 is in contact with the crankpin 55. Grinding may be started.

  Next, the air cylinder 22 is operated in a state where the guide member 18 abuts on the crank pin 55 being ground and follows the turning motion of the crank pin 55, and the reference V base 19 of the measuring head 17 is moved to the work 55. Make contact. By this operation, the guide member 18 is slightly separated from the crankpin 55. At the same time, the measuring head 17 follows the turning motion of the crank pin 55 while keeping the V groove of the reference V base 19 in contact with the crank pin 55.

  Further, when the reference V base 19 is brought into contact with the work 55, the displacement detector 20 attached to the bottom of the V groove of the reference V base 19 detects the displacement of the diameter of the crank pin 55. FIG. 6 shows the measurement state of the crank pin 55.

  When the measurement is completed, the air cylinder 21 and the air cylinder 22 are operated, and the guide member 18 and the measurement head 17 are retracted from the crankpin 55.

  In this way, the diameter can be measured at any time during the processing of the crankpin 55. In addition, it is possible to maintain the measurement state just before the end of machining, detect that the crankpin 55 is finished to a predetermined dimension, and send a sizing signal to the grinding machine 80.

  As described above, according to the pin diameter measuring apparatus 10 according to the present invention, the measuring head 17 can move along the outer periphery of the grinding wheel 84 while maintaining a constant posture, and the measuring head can be operated with a simple mechanism. 17 and the grinding wheel 84 can be prevented, and the measuring head 17 can be caused to follow a cylindrical workpiece (crank pin 55) that revolves around the rotation axis C. Further, since there is no change in the posture of the measurement head 17, there is no change in the measurement value due to gravity. Furthermore, since the measuring force is directed in the direction of the grinding wheel 84, there is little decrease in measurement accuracy due to deformation of the cylindrical workpiece (crank pin 55).

  In the above-described embodiment, the air cylinders 21 and 22 are used as the link driving means and the holder arm driving means. However, the present invention is not limited to this, and known driving means such as a hydraulic cylinder and an electric motor can be used. .

  Further, although the flat four-bar linkage mechanism 15 is lowered by its own weight, it may be lowered by the thrust of the air cylinder 21, and conversely, the air cylinder 21 is operated so that its own weight is reduced. May be. When the planar four-bar linkage mechanism 15 is operated so as to reduce its own weight, it is possible to realize a stable measurement with high accuracy by suppressing the deflection of the entire workpiece, and to reduce wear of the contact plate 18A of the guide member 18; The crank pin 55 is not damaged.

The side view showing the pin diameter measuring apparatus which concerns on embodiment of this invention Enlarged view explaining the measuring head Conceptual diagram explaining the processing of the crankpin Side view explaining relative trajectory of crankpin to grinding wheel Side view showing how the guide member follows the turning motion of the crankpin Side view showing the measurement state of the crankpin

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Pin diameter measuring apparatus, 11 ... Fixed arm, 12 ... Movable arm, 13 ... Connection arm, 14 ... Supporting point member (rotating fulcrum), 15 ... Planar four-bar linkage mechanism, 16 ... Holder arm, 17 ... Measuring head, 18 DESCRIPTION OF SYMBOLS ... Guide member, 19 ... Reference | standard V stand, 20 ... Displacement detector, 21 ... Air cylinder (link drive means), 22 ... Air cylinder (holder arm drive means), 55 ... Crank pin (workpiece), 82 ... Turret, 84: Grinding wheel (blade), C: Axis (rotation axis), L: Link arm length (link length, distance between rotation fulcrums at both ends)

Claims (4)

In a pin diameter measuring device that measures the diameter of a cylindrical workpiece that is processed while turning around a rotation axis,
A fixed arm fixed to the tool post moving in the cutting direction, a movable arm moving in parallel with the fixed arm, and two connecting arms connected to the fixed arm and the movable arm at rotation fulcrums and parallel to each other A plane four-bar linkage mechanism consisting of
A pin diameter measuring apparatus comprising: a measuring head which is held by the planar four-bar linkage mechanism and follows the turning motion of the work while being in contact with the work to measure the diameter of the work. Link driving means for driving the planar four-bar linkage mechanism;
A guide member attached to the tip of the movable arm and contacting the workpiece;
A holder arm swingably attached to the movable arm;
Holder arm driving means for swinging the holder arm with respect to the movable arm,
The measuring head is attached to the holder arm;
The pin diameter measuring device according to claim 1, wherein the guide member or the measuring head is configured to be able to follow a turning motion of the workpiece while being in contact with the workpiece. The tool provided on the tool post is a grinding wheel,
The pin diameter measurement according to claim 1 or 2, wherein a link length (distance between rotation fulcrums) of the connecting arm is equal to a distance from an end of the guide member to a rotation center of the grinding wheel. apparatus. The measuring head comprises a reference V base and a displacement detector,
4. The pin diameter according to claim 1, wherein the guide member is released from contact with the workpiece when the reference V base contacts the workpiece. 5. measuring device.

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