JP4555618B2 - Blade break sensor - Google Patents

Description

  The present invention relates to a blade break sensor that detects a blade break of a tool.

  The tool breakage detection device is used to detect breakage of a tool such as a drill or a reamer mounted on a machine tool or the like. The blade break sensor used in this blade break detection device is formed by supporting a conductive detection piece on a conductive support member and connecting an electric wire connected to the support member to the blade break detection device. Further, the support member of the blade break sensor formed in this way is attached to a rotatable arm or the like, and whether or not the detection piece comes into contact with a tool held at a predetermined position on the rotation plane of the arm, Used to detect tool breakage. That is, a detection current is allowed to flow between the detection piece and the tool via the electric wire from the blade breakage detection device, and if the detection piece contacts the blade edge of the tool and is energized, it is determined that the blade is not broken. If not, it is determined that the blade is broken (for example, see Patent Document 1).

  The detection piece described in Patent Document 1 is formed of a conductive material, a slit is formed in the extending direction of the flat base end portion, and a screw is passed through the slit to detect on the support surface of the support member by a press fitting. It is formed by pressing and fixing a piece. Further, the detection piece is held by the rotating arm via the support member so that the flat plate surface comes into contact with the cutting edge of the tool. That is, when the detection piece comes into contact with the tool, the detection piece is bent to absorb the contact force. However, the detection piece may be damaged when the detection piece is strongly pressed against the tool or sometimes contacts the rotating tool. In this regard, in the blade break sensor described in Patent Document 1, the damaged detection piece is pulled out by loosening the screw of the presser fitting, and the new detection piece is inserted between the presser fitting and the support member so that they can be replaced. .

Japanese Utility Model Publication No. 7-5933 (see FIG. 1-2, page 2)

  By the way, if the pressing force of the metal fitting is loosened by vibration, the detection piece may be displaced within the support surface, and the longitudinal direction of the detection piece may be inclined with respect to the longitudinal direction of the support member. Thus, when the detection piece is tilted with respect to the support member, the trajectory of the detection piece driven by the rotating arm deviates from the original trajectory. As a result, when the track of the detection piece deviates from the cutting edge portion of the tool, it is erroneously detected that the tool is broken despite the soundness of the tool. On the contrary, although the cutting edge portion of the tool is broken, the detection piece may come into contact with the remaining portion of the damaged cutting edge, and it is erroneously detected that the blade is not broken. In particular, when the entire length of the detection piece is long, the trajectory of the detection piece is greatly shifted due to a slight inclination of the detection piece.

  An object of the present invention is to reduce the detection error by reducing the inclination of the detection piece with respect to the support member even if the presser fitting for holding the detection piece against the support member is loosened.

  In order to solve the above-described problems, the present invention provides a conductive detection piece having a slit formed in the extending direction of the base end portion, a conductive support member that supports the detection piece, and a base end portion. A pressing means that presses and fixes the support member to the support surface of the support member, and an electric wire connected to the support member, and the support member is rotated so that the detection piece comes into contact with the tool held at a predetermined position. In the blade break sensor used to detect blade breakage depending on whether or not the detection piece and the tool are energized, a groove having a width corresponding to the base end of the detection piece is formed on the support surface of the support member. The base end portion of the detection piece is housed in the housing.

  That is, since the base end portion of the detection piece is housed in the groove of the support member, the detection piece can be prevented from being inclined with respect to the support member even if the screw of the pressing metal is loosened. As a result, it is possible to reduce the detection of the tool breakage due to the detection piece trajectory coming off the tool edge.

  In this case, the groove for accommodating the base end portion of the detection piece is formed deeper than the thickness of the base end portion of the detection piece, and a convex portion that contacts the base end portion of the detection piece at a position corresponding to the groove of the pressing means. Can be formed. According to this, it is possible to avoid an assembly failure such that the base end portion of the detection piece is mounted in a state where it is mounted on the edge of the groove of the support member.

  The pressing means is a pressing metal that presses and fixes the base end to the support surface of the support member through a screw in the slit of the detection piece. A locking protrusion is provided on the convex part of the pressing metal, and the locking protrusion is engaged. It is possible to employ a configuration in which a mating locking hole is provided on the tip side of the detection piece slit. According to this, even if the screw of the pressing metal is loosened, it is possible to prevent the detection piece from falling off.

  According to the present invention, even if the presser fitting that holds the detection piece against the support member is loosened, the inclination of the detection piece with respect to the support member can be reduced and false detection can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a blade break sensor according to the present embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is an overall view showing an outline of a blade breakage detection apparatus using the blade breakage sensor of the present embodiment. FIG. 5 is a partially broken perspective view for explaining the assembly of the blade break sensor of the present embodiment.

  The blade breakage detection apparatus according to the present embodiment detects, for example, breakage of a tool 1 such as a drill or a reamer mounted on a machine tool or the like. Such a blade breakage detection device is configured to include a blade breakage sensor 3 at the tip of an arm 5 that can be rotated by a motor 6. In addition, the blade breakage detection apparatus includes a control panel 7 that controls the apparatus. The control panel 7 is connected to the tool 1 via a cable 12 and is connected to the blade break sensor 3 via a cable 13. Further, the control panel 7 is configured to control the motor 6.

  The blade break sensor 3 is configured by supporting a conductive detection piece 11 on a conductive support member 9. The support member 9 is connected to the cable 13. A connecting portion between the support member 9 and the cable 13 is buried and fixed in a resin block 15. The block 15 is fixed to the tip of the arm 5 with a screw or the like. The arm 5 is formed to be rotatable in the direction of an arrow 19 around the axis of the motor 6 so that the detection piece 11 of the blade break sensor 3 is advanced and retracted to the standby position of the tool 1 where the tool 1 returns after the machining operation. It has become.

  The blade breakage detection apparatus configured as described above performs an operation of detecting the blade breakage before or after the machining operation of the tool 1, for example. Specifically, the control panel 7 controls the motor 6 to move the arm 5 to the standby position of the tool 1. Then, when it is determined that the tip of the arm 5 is at the standby position of the tool 1 by, for example, the driving time of the motor 6 or the like, it is determined whether or not the cables 12 and 13 are energized by passing a detection current. As a result of this determination, if energized, the blade break sensor 3 is in contact with the tool 1, so it is determined that the blade is not broken. On the contrary, if the power is not energized, it is determined that the tool is broken because the blade break sensor 3 is not in contact with the tool 1, and for example, a blade break display or an alarm is output.

  Next, the blade break sensor according to the characteristic part of the present embodiment will be described in detail. As shown in FIGS. 1 to 5, the detection piece 11 of the blade break sensor 3 is formed in, for example, a flat plate shape, and a slit 25 is formed in the extending direction of the base end portion. That is, the base end portion of the detection piece 11 is divided into two forks. The support member 9 is formed in a prismatic shape so as to protrude from the block 15 and extend. A support surface 27 is formed on one of the side surfaces of the support member 9. The detection piece 11 is configured such that the base end portion is placed on and supported by the support surface 27. The support surface 27 is formed so as to be orthogonal to the rotation plane of the arm 5, and the flat plate surface of the detection piece 11 placed on the support surface 27 comes into contact with the cutting edge of the tool 1. Thereby, when the detection piece 11 contacts the tool 1, the detection piece 11 bends and absorbs force.

  A screw hole 29 is formed on the support surface 27 at a position corresponding to the slit 25 of the detection piece 11. The screw hole 29 is screwed with a screw 31 for fixing a pressing metal 33 serving as a pressing means. The holding metal fitting 33 is composed of a surface portion and a bent portion. The surface portion of the presser fitting 33 is formed so as to extend along the support member 9 so as to cover the support surface 27, and a hole 35 through which the screw 31 is inserted is provided in the central portion. The bent portion is formed so as to contact both side surfaces of the support surface 27. As a result, the presser fitting 33 covers the half of the support member 9 on the support surface 27 side.

  On the other hand, the support member 9 is formed in a cylindrical shape in a portion embedded in the block 15. A notch is formed in the cylindrical portion, and the cable 13 is connected to the notch with a screw 37. A part of the cable 13 located outside the block 15 is made of resin and covered with a spiral protective member 39. The protection member 39 is connected to the block 15.

  The groove 41 which is the first characteristic part of the present embodiment is formed in the support surface 27. The groove 41 is formed in the extending direction of the support member 9. The width of the groove 41 is substantially the same as the width of the detection piece 11. Thereby, since the base end part of the detection piece 11 is accommodated in the groove 41 and the rattling is suppressed, the detection piece 11 is inclined with respect to the support member 9 even if the screw 31 fixing the presser fitting 33 is loosened ( For example, θ) can be suppressed. As a result, the trajectory of the detection piece 11 can be prevented from coming off from the cutting edge of the tool 1 as in the trajectory of the detection piece 11a, for example.

  The second feature of the present embodiment is that the groove 41 is formed deeper than the thickness of the base end portion of the detection piece 11, and abuts the base end portion of the detection piece 11 at a position corresponding to the groove 41 of the presser fitting 33. This is a point provided with a convex portion 43. For example, the convex portion 43 is formed at two locations by denting the pressing metal fitting 33 and is arranged on the object with the hole 35 in the center portion interposed therebetween. According to this, it is possible to avoid an assembly failure such as attachment in a state where the base end portion of the detection piece 11 rides on the edge of the groove 41. The height of the convex portion 43 is formed higher than the dimension obtained by subtracting the thickness of the detection piece 11 from the depth of the groove 41.

  The third feature of the present embodiment is that a locking projection 45 is provided on each convex portion 43 of the presser fitting 33, and the locking hole 47 that fits the locking projection 45 is located on the tip side from the slit 25 of the detection piece 11. It is a point provided. The locking projection 45 is formed by denting the convex portion 43 from the back side. According to this, even if the screw 31 of the presser fitting 33 is loosened, the locking projection 45 is caught in the locking hole 47, so that the detection piece 11 is difficult to come off. Further, the locking protrusion 45 is provided on the object with the central hole 35 sandwiched between the presser fitting 33. This is preferable because any one of the locking projections 45 is caught in the locking hole 47 regardless of the mounting direction of the presser fitting 33.

  The fourth feature of the present embodiment is that a resin layer 49 different from the mold resin that forms the block 15 is provided at the boundary between the block 15 and the connection portion between the support member 9 and the cable 13. Thereby, for example, even if a coolant for cooling the tool is applied to the blade break sensor 3, the coolant can be prevented from entering the connecting portion between the support member 9 and the cable 13. In particular, when the cable 13 is fixed to the support member 9 with an adhesive, the adhesive can be prevented from being deteriorated by the coolant. Further, according to the resin layer 49, the influence of heat applied to the connection portion when the block 15 is formed by filling the mold resin can be reduced.

  Moreover, in this embodiment, when exchanging the detection piece 11, in order to make it easy to insert in the groove 41, it is preferable to drop the corner of the insertion opening of the groove 41. Moreover, in this embodiment, although the convex part 43 and the latching protrusion 45 were formed by denting the pressing metal fitting 33, it is not restricted to this and can also be attached separately. The locking hole 47 can use a hole for hanging the detection piece 11 when the detection piece 11 is heat-treated. The resin layer 49 can be formed of, for example, a heat-shrinkable tube. In this case, what applied the adhesive agent inside the tube can be used.

It is a figure which shows the blade break sensor of this embodiment. It is sectional drawing in line II-II of FIG. It is sectional drawing in line III-III of FIG. 1 is an overall view showing an outline of a blade breakage detection apparatus using a blade breakage sensor of the present embodiment. It is the partially broken perspective view explaining the assembly of the blade break sensor of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tool 3 Blade break sensor 5 Arm 7 Control panel 9 Support member 11 Detection piece 12, 13 Cable 15 Block 25 Slit 27 Support surface 33 Presser fitting 41 Groove 43 Protrusion 45 Locking protrusion 47 Locking hole

Claims (4)

A conductive detection piece having a slit formed in the extending direction of the base end, a conductive support member that supports the detection piece, and the base end is pressed and fixed to the support surface of the support member. A pressing means and an electric wire connected to the support member, the support member is rotated so that the detection piece comes into contact with a tool held at a predetermined position, and the detection piece and the tool In the blade break sensor used to detect the blade breakage depending on the presence or absence of energization with
A blade break sensor, wherein a groove having a width corresponding to a base end portion of the detection piece is formed on a support surface of the support member, and the base end portion of the detection piece is accommodated in the groove.   The groove formed on the support surface of the support member is formed deeper than the thickness of the base end portion of the detection piece, and the pressing means is a convex portion that contacts the base end portion at a position corresponding to the groove. The blade break sensor according to claim 1, wherein the blade break sensor is formed. The pressing means is a press fitting that presses and fixes the base end portion to a support surface of the support member through a screw in the slit of the detection piece,
3. A locking projection is provided on the convex portion of the presser fitting, and a locking hole with which the locking projection engages is provided on the tip side of the slit of the detection piece. The blade break sensor described in 1. The connection portion between the support member and the electric wire is surrounded by a mold resin, and a resin layer different from the mold resin is formed at a boundary portion between the mold resin layer and the connection portion between the support member and the electric wire. The blade break sensor according to any one of 1 to 3.

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