JP2011167814A - Sensor for breakage detection device, and breakage detection device equipped with the sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor capable facilitating the detection of the presence/absence of the breakage of a tool in which only a part of a plurality of cutting edges is broken, and a breakage detection device equipped with the sensor. <P>SOLUTION: The sensor 10 for the breakage detection device detecting the presence/absence of the breakage of the cutting edges 311, 312 of the tool 30 provided with the plurality of the cutting edges 311, 312 at rotation symmetry positions to a center axis at one end, and where the cutting edges 311, 312 have shapes projecting out in the center axis direction includes: a head 12 which is a part pressed by one end of the tool 20 and supported so as to be displaced in its center axis direction to an original position that is not pressed by the tool 30 and tilted to a virtual plane surface vertical to its center axis; a spring 13 automatically returning the head 12 to an original position; and a limit switch 14 detecting a moving distance which the head 12 pressed by the tool 30 moves in the center axis direction, and outputting a detection signal indicating that the head 12 moves from the original position by a predetermined distance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sensor for detecting breakage of a tool and a breakage detection apparatus including the sensor.

  Conventionally, as an example of a breakage detection device for detecting breakage of a tool, there is one disclosed in Patent Document 1.

  The breakage detection device shown in Patent Document 1 is provided at a position facing a tool to be measured, and outputs a contact signal when it comes in contact with the tool, and moves the contact sensor forward and backward. And a tool length measuring device including a cylinder with a built-in position detector such as an encoder. In this breakage detection device, the contact sensor is moved from the base point toward the tool by the cylinder, and the length of the tool is measured from the moving distance until the contact sensor touches the tip of the tool at a predetermined position. Then, the presence or absence of breakage is detected by comparing the measured length with the length of a normal tool that is not broken.

Japanese Patent Laid-Open No. 10-138094

  The shape of the tool varies depending on the machining shape to be machined, and there are various types. For example, there is a tool tip having a shape in which a plurality of (for example, two or three) cutting edges are arranged rotationally symmetrically with respect to the center axis of the tool and project in the direction of the center axis of the tool. Note that a tool having a shape in which two cutting edges are arranged rotationally symmetrically with respect to the center axis of the tool and protrudes in the axial direction of the tool at the tip end of the tool has three blades at the tip end of the tool. A tool having a shape in which the cutting edge is disposed rotationally symmetrically with respect to the central axis of the tool and protrudes in the axial direction of the tool is also referred to as a three-blade tool. In this two-blade tool, only one of the two cutting edges may be broken. In a three-blade tool, only one or two of the three cutting edges may be broken.

  By the way, in the above-described breakage detection device, when trying to detect breakage of a two-blade tool in which only one of the two cutting edges is broken, the contact sensor is moved until it touches the tip of the tool at a predetermined position. The contact sensor touches the blade edge that is not bent and outputs a signal. That is, even if one of the two cutting edges is broken, the contact sensor outputs a signal indicating that the tip of the tool has come into contact as in the case where neither of the two cutting edges is broken (normal case). . Therefore, the movement distance until the contact sensor touches the tip of the tool is the same when only one of the two cutting edges is broken or when the two cutting edges are not broken. That is, the length of the tool to be measured is equivalent to the length of a normal tool that is not broken, and it cannot be detected that only one of the two cutting edges is broken. Similarly, in the case of a three-blade tool, it cannot be detected that only one or two of the three cutting edges are broken. As described above, the above-described breakage detection device may not be able to detect breakage of a tool in which only some of the blade edges are broken.

  The present invention has been made in view of the above problems, and provides a sensor that can easily detect the presence or absence of breakage of a tool in which only some of the cutting edges of a plurality of cutting edges are broken, and a breakage detection apparatus including the sensor. For the purpose.

In order to achieve the above object, a sensor for a breakage detection device according to claim 1,
A sensor for a breakage detecting device, wherein a plurality of cutting edges are provided at one end at a rotationally symmetric position with respect to the central axis, and detects whether the cutting edge is broken in a tool having a shape in which the cutting edge protrudes in the central axis direction. ,
A part that is pressed by one end of a tool, and can be displaced in the direction of its center axis with respect to the origin position that is not pressed by the tool, and can be tilted with respect to a virtual plane perpendicular to its center axis A supported pressed portion; and
A restoring force generator that automatically returns the pressed part to the origin position;
And a detection unit that detects a movement distance of the pressed part that is pressed by the tool and moves in the central axis direction, and outputs a detection signal indicating that the pressed part has moved a predetermined distance from the origin position. Is.

  By doing in this way, for example, when the pressed part is pressed by the tool with the center axis of the tool and the center axis of the pressed part being matched, the pressed part is not broken at all. When pressed by a tool, a position that is rotationally symmetric with respect to its own central axis is pressed. When the pressed portion is thus pressed at a position that is rotationally symmetric with respect to its own central axis, the pressed portion is displaced (that is, translated) along its own central axis, so that it moves a predetermined distance from the origin position. Cheap.

  On the other hand, when a part of the plurality of cutting edges is pressed by a broken tool, the pressed part is pressed at a position biased with respect to its own central axis. When the pressed portion is pressed at a position biased with respect to its own central axis in this way, the pressed portion is inclined with respect to a virtual plane perpendicular to the central axis of the pressed portion, so that it becomes difficult for the pressed portion to move a predetermined distance from the origin position.

  Therefore, when the tool and the pressed part are relatively moved and the pressed part is pressed with the tool, when the pressed part is pressed with a normal tool, only some of the cutting edges are out of the plurality of cutting edges. When the pressed part is pressed with a folded tool, the relative movement distance between the tool and the pressed part required until the detection unit outputs a detection signal can be made different. Therefore, it is possible to easily detect the presence or absence of breakage of a tool having a plurality of cutting edges provided at rotational symmetry positions with respect to the central axis at one end.

  According to a second aspect of the present invention, there is provided a case having a hole having a circular cross section, and slidably storing the pressed part in the hole, and the pressed part is in contact with one end of the tool. A columnar member having both ends as a circular contact surface and a circular back surface opposite to the contact surface, and the columnar member is in a direction perpendicular to the central axis of the pressed portion between the contact surface and the back surface. It may be a part of a sphere having the thickest part.

  In this way, when the pressed part is housed in the hole of the case, the pressed part is a spherical body having a thickest portion in the direction perpendicular to its central axis between the contact surface and the back surface. By setting it as a part, the pressed part can be easily inclined with respect to a virtual plane perpendicular to the center axis of the pressed part.

  Further, the restoring force generator can be configured by a member that uses air, magnetic force, elastic force, or the like. However, as shown in claim 3, the restoring force generator can be easily configured by using an elastic member.

  Further, as shown in claim 4, when the pressed part moves a predetermined distance from the origin position, the detecting part comes into direct or indirect contact with the pressed part, and the pressed part is predetermined from the origin position. A contact-type limit switch that outputs a detection signal indicating that the distance has moved, or, as shown in claim 5, when the pressed part moves a predetermined distance from the origin position, the pressed part moves a predetermined distance from the origin position. It is possible to employ a non-contact type limit switch that outputs a signal indicating that this has been done. Furthermore, as shown in claim 6, the detection unit may employ a distance sensor that outputs a signal corresponding to the moving distance from the origin position of the pressed portion.

Further, in order to achieve the above object, a sensor for a breakage detection device according to claim 7,
A sensor for a breakage detecting device that detects the presence or absence of breakage of a blade edge in a tool provided with a plurality of blade edges at a rotationally symmetric position at one end with respect to a central axis,
This is a part that is pressed by one end of the tool, and can be displaced in the direction of its own central axis with respect to the origin position that is not pressed by the tool, and can be tilted with respect to a virtual plane perpendicular to its own central axis. Pressed part,
A restoring force generator that automatically returns the pressed part to the origin position;
A plurality of detection signals indicating that when the pressed portion pressed by the tool moves a predetermined distance from the origin position in the central axis direction, the pressed portion contacts and the pressed portion moves a predetermined distance from the origin position A detection unit including a contact type limit switch of
The pressed part has a plurality of protrusions at a rotationally symmetric position with respect to its center position on the back surface facing the contact surface with which one end of the tool contacts.
The plurality of limit switches are provided at positions facing the plurality of protrusions.

  In this way, when the pressed part is pressed with a normal tool, detection signals are output from all limit switches, and the pressed part is a tool in which only some of the cutting edges are broken. When is pressed, a detection signal is output from some limit switches. Therefore, the number of limit switches that output detection signals when the pressed part is pressed with a normal tool and when the pressed part is pressed with a tool in which only some of the cutting edges are broken. Can be changed. In other words, the mode of the detection signal can be changed. Therefore, it is possible to easily detect the presence or absence of breakage of a tool having a plurality of cutting edges provided at rotational symmetry positions with respect to the central axis at one end.

  In addition, regarding the eighth and ninth aspects, since the operation and effect are the same as those of the above-described second and third aspects, description thereof will be omitted.

Moreover, in order to achieve the said objective, the breakage detection apparatus of Claim 10 is provided.
A sensor for a breakage detection device according to any one of claims 1 to 6,
Driving means for relatively moving the sensor and the tool from the reference position by matching the center axis of the tool and the center axis of the pressed part in order to press the pressed part with the tool;
Measuring means for measuring a moving distance that the sensor and the tool have moved relative to the reference position before the detection signal is output from the detection unit;
And a breakage detecting unit that detects whether or not the blade edge is broken depending on whether or not the moving distance measured by the measuring unit matches a preset reference distance.

  By doing in this way, when the pressed part is pressed by a normal tool in which all the cutting edges are not broken, a position that is rotationally symmetric with respect to its own central axis is pressed. When the pressed portion is thus pressed at a position that is rotationally symmetric with respect to its own central axis, the pressed portion is displaced (that is, translated) along its own central axis, so that it moves a predetermined distance from the origin position. Cheap.

  On the other hand, when a part of the plurality of cutting edges is pressed by a broken tool, the pressed part is pressed at a position biased with respect to its own central axis. When the pressed portion is pressed at a position biased with respect to its own central axis in this way, the pressed portion is inclined with respect to a virtual plane perpendicular to the central axis of the pressed portion, so that it becomes difficult for the pressed portion to move a predetermined distance from the origin position.

  Therefore, when the pressed part is pressed with a normal tool and when the pressed part is pressed with a tool in which only some of the cutting edges are broken, a detection signal is output from the sensor detection unit. By the time the sensor and the tool are moved relative to each other from the reference position, the moving distance can be made different. Therefore, it is possible to easily detect the presence or absence of breakage of a tool having a plurality of cutting edges provided at rotational symmetry positions with respect to the central axis at one end.

Moreover, in order to achieve the said objective, the breakage detection apparatus of Claim 11 is the following.
A sensor for a breakage detection device according to any one of claims 1 to 6,
In order to press the pressed part with the tool, the driving unit moves the sensor and the tool relative to each other by a predetermined distance from the reference position by matching the central axis of the tool with the central axis of the pressed part. When,
A breakage detection unit that detects whether or not the cutting edge is broken depending on whether a detection signal is output from the detection unit in a state where the sensor and the tool are relatively moved by a preset distance. It is what.

  In addition, since the effect | action and effect in this Claim 11 are the same as the effect | action and effect in the above-mentioned Claim 10, description is abbreviate | omitted.

Moreover, in order to achieve the said objective, the breakage detection apparatus of Claim 12 is
A sensor for a breakage detection device according to claim 6;
Driving means for relatively moving the sensor and the tool from the reference position by matching the center axis of the tool and the center axis of the pressed part in order to press the pressed part with the tool;
Measurement means for measuring the movement distance of the sensor and the tool moved relative to the reference position based on a signal corresponding to the movement distance output from the detection unit;
And a breakage detection unit that detects the presence or absence of breakage of the cutting edge based on the moving distance measured by the measuring means.

  By doing this, when the tool is normal, when it is broken, and when it is broken, the distance traveled by the sensor and the tool is measured according to the degree of breakage. be able to. Therefore, it is possible to easily detect the presence or absence of breakage of a tool provided with a plurality of cutting edges at rotational symmetry positions with respect to the central axis at one end, and it is also possible to detect the degree of breakage.

Moreover, in order to achieve the said objective, the breakage detection apparatus of Claim 13 is
A sensor for a breakage detection device according to any one of claims 7 to 9,
Driving means for relatively moving the sensor and the tool from the reference position by matching the center axis of the tool and the center axis of the pressed part in order to press the pressed part with the tool;
A breakage detection unit that detects the presence or absence of breakage of the cutting edge based on the number of limit switches that output detection signals among a plurality of limit switches in a state where the sensor and the tool are relatively moved by a predetermined distance. , That is.

  In this way, when the pressed part is pressed with a normal tool, detection signals are output from all limit switches, and the pressed part is a tool in which only some of the cutting edges are broken. When is pressed, a detection signal is output from some limit switches. Therefore, the number of limit switches that output detection signals when the pressed part is pressed with a normal tool and when the pressed part is pressed with a tool in which only some of the cutting edges are broken. Can be changed. In other words, the mode of the detection signal can be changed. Therefore, it is possible to easily detect the presence or absence of breakage of a tool having a plurality of cutting edges provided at rotational symmetry positions with respect to the central axis at one end.

It is a schematic diagram which shows the break detection apparatus in embodiment of this invention, and the tool which is a detection symmetry. (A) is a front view of the sensor in embodiment of this invention, (b) is II-b-II-b sectional drawing of Fig.2 (a). (A) is a front view of the head in the embodiment of the present invention, and (b) is a sectional view taken along line III-b-III-b in FIG. 3 (a). (A) is sectional drawing of the sensor at the time of being pressed with a normal tool, (b) is an image figure which shows the contact surface of a head at the time of being pressed with a normal tool. (A) is sectional drawing of a sensor when a part of blade edge is pressed with a broken tool, (b) is an image figure which shows the contact surface of a head when a part of blade edge is pressed with a broken tool It is. It is sectional drawing of the sensor in the modification 1. FIG. It is sectional drawing of the sensor in the modification 2. It is sectional drawing of the sensor in the modification 3. (A) is sectional drawing of the sensor in the modification 4, (b) is a front view of a detection part, (c) is a front view of the back surface side of a head. (A) is a side view of the tool which is the object of breakage detection, and (b) is a front view of the tool (drawing seen from the direction of the thick arrow in FIG. 10 (a)). (A) is a top view of the workpiece processed with the tool shown in FIG. 10, (b) is XI-b-XI-b sectional drawing of Fig.11 (a).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The breakage detection apparatus according to the embodiment of the present invention relates to a breakage detection apparatus that detects the presence or absence of breakage of a tool (cutting tool) 30 that cuts a workpiece 50 to be processed. In particular, the breakage detection apparatus according to the embodiment of the present invention is suitable for detecting the presence or absence of breakage of the blade edge in the tool 30 provided with a plurality of blade edges at rotationally symmetrical positions with respect to the central axis at one end. .

  There are various types of tools for performing processing on a processing target, depending on the processing shape of the processing target. As an example of the processing shape in the processing target, there is a processing hole 51 provided in the workpiece 50 shown in FIGS. 11A and 11B, for example. The processed hole 51 is a bottomed hole having a circular shape and having a mountain shape (peak portion 52) protruding from the bottom (valley portion 54) to the opening side (upper side in FIG. 11B). . In other words, the processed hole 51 is a bottomed cylindrical hole and has a mountain shape with the bottom of the hole protruding to the opening side.

  The peak portion 52 is formed by the opening area of the processing hole 51 becoming narrower from the bottom (the valley portion 54) toward the opening side in the central axis direction of the processing hole 51. That is, the peak portion 52 has the inclined portion 53 in which the distance from the wall surface parallel to the central axis of the processed hole 51 increases as it goes from the bottom (the valley portion 54) to the opening side in the central axis direction of the processed hole 51. In other words, the cross-sectional area of the peak portion 52 on the plane perpendicular to the central axis of the processed hole 51 becomes smaller as it goes from the bottom (the valley portion 54) toward the opening side in the central axis direction of the processed hole 51.

  The top of the peak portion 52 may be a circular plane having the same central axis as the central axis of the processing hole 51. The workpiece 50 is provided with a through hole 55 penetrating from the top of the peak portion 52 to the outside of the workpiece 50. Such a processed hole 51 is suitable as a hole into which a brake pipe (for example, iron) is press-fitted.

  As described above, when cutting the workpiece 50, it is preferable to use, for example, a tool 30 as shown in FIGS. 10 (a) and 10 (b). In addition, this tool 30 is mounted | worn with a spindle apparatus (illustration omitted) in the state hold | maintained at the tool holder 40 (refer FIG. 1), for example. When the rotating part of the spindle device rotates at a high speed, the tool holder 40 rotates at a high speed together with the rotating part, thereby rotating at a high speed. The tool 30 can be cut when the cutting edges 311 and 312 come into contact with the workpiece 50 while rotating at a high speed.

  As shown in FIGS. 10A and 10B, the tool 30 includes a front end side on which the cutting edges 311 and 312 are provided, and a rear end side (held on the tool holder 40) with the stepped portions 341 and 342 as boundaries. The diameter can be divided into a large diameter with respect to the tip side. Then, the tool 30 has two cutting edges at one end of the tool 30 (the end on the side in contact with the workpiece 50) in order to perform the cutting of the workpiece shape as described above on the workpiece 50. 311 and 312 are rotationally symmetric with respect to the center axis of the tool 30 and have a shape protruding in the direction of the center axis of the tool 30.

  The cutting edges 311 and 312 include industrial diamond and the like, and include inclined portions 311a and 312a, tip portions 311c and 312c, respectively. That is, the blade edge 311 includes an inclined portion 311a and a tip portion 311c. Similarly, the blade edge 312 includes an inclined portion 312a and a tip portion 312c.

  The inclined portions 311a and 312a are spaced apart from the center axis of the tool 30 as they go to the tip of the tool 30 in the direction of the center axis of the tool 30, and the tip portions 311c and 312c are provided at the forefront. Further, the inclined portions 311a and 312a are side walls 311b and 312b which are side surfaces, and the front side surfaces which are the end portions on the side walls 311b and 312b are made of industrial diamond. Moreover, the front-end | tip parts 311c and 312c and the trough parts 321 and 322 are also formed with the industrial diamond. The valley portions 321 and 322 are provided with coolant holes 331 and 332 for supplying coolant (a fluid for lubricating cooling and mist-like oil).

  In the present embodiment, as a break detection target, at one end, the two cutting edges 311 and 312 are arranged rotationally symmetrically with respect to the central axis of the tool 30, and the shape protrudes in the direction of the central axis of the tool 30. Although the example which employ | adopts the tool 30 which has this is demonstrated, this invention is not limited to this. The present invention is a tool in which a plurality of (for example, three) cutting edges are provided at one end at rotationally symmetric positions with respect to the central axis of the tool, and the cutting edge protrudes in the central axis direction of the tool 30. Can be adopted.

  Note that a tool having a shape in which two cutting edges are arranged rotationally symmetrically with respect to the center axis of the tool and protrudes in the axial direction of the tool at the tip end of the tool has three blades at the tip end of the tool. A tool having a shape in which the cutting edge is disposed rotationally symmetrically with respect to the central axis of the tool and protrudes in the axial direction of the tool is also referred to as a three-blade tool.

In such a two-blade tool 30, only one of the two cutting edges 311 and 312 may be broken. When it is attempted to detect the breakage of the two-blade tool 30 in which only one of the two cutting edges 311 and 312 is broken in the breakage detection device in the prior art, the contact sensor is set to the tip of the tool 30 at a predetermined position. If it is moved until it touches either 311c or 312c, the contact sensor will touch the unbroken blade edge (one of the blade edges 311 and 312) and output a signal. That is, in the contact sensor, even if one of the two cutting edges 311, 312 is broken, the tip 311 c of the tool 30, as in the case where none of the two cutting edges 311, 312 is broken (normal case). A signal indicating that 312c has touched is output. Therefore, the movement distance until the contact sensor touches the tip portions 311c and 312c of the tool 30 is the case where only one of the two cutting edges 311 and 312 is broken and the two cutting edges 311 and 312 are both broken. It will be the same with no normal case. That is, the length of the tool 30 to be measured is equivalent to the length of the normal tool 30 that is not broken, and the two cutting edges 311 and 312.
It is impossible to detect that only one of them is broken.

  The breakage detection apparatus in the present embodiment is intended to solve such a problem. As shown in FIG. 1, the breakage detection apparatus includes a sensor 10 and a breakage detection unit 20.

  Here, the sensor 10 of the breakage detection apparatus will be described with reference to FIGS. The sensor 10 is a sensor for a breakage detection device that detects the presence or absence of breakage of the two cutting edges 311 and 312 in the two-blade tool 30 as described above.

  As shown in FIGS. 1, 2, etc., the sensor 10 is a part that is pressed by one end (the cutting edges 311, 312) of the tool 30 as a main component, and is at the origin position that is not pressed by the tool 30. On the other hand, the head 12 (pressed portion) supported so as to be able to be displaced in the direction of its own central axis and tiltable with respect to a virtual plane perpendicular to its central axis, and the head 12 are automatically brought to the origin position. The return spring 13 (restoring force generating portion) and the movement distance of the head 12 pressed by the tool 30 moving in the central axis direction are detected, and a detection signal indicating that the head 12 has moved a predetermined distance from the origin position is output. A limit switch (detection unit) 14 is provided. In addition, in the present embodiment, a center point support portion 152 that supports the center point of the head 12, and a holding portion 151 that is attached with the center point support portion 152 and holds the center point support portion 152, A spring 16 is provided between the holding portion 151 and the limit switch 14.

  The head 12, the spring 13, the limit switch 14, the holding portion 151 to which the center point support portion 152 is attached, and the spring 16 are housed in the case 11. In addition, these are the head 12 from the front part 115 (one end surface) of the case 11, the spring 13 (the center point support part 152 is disposed between the head 12 and the holding part 151 similarly to the spring 13), and the holding. The portion 151, the spring 16, and the limit switch 14 are housed in the case 11 in this order. As shown in FIG. 1, when the head 12 is not pressed by the tool 30, the central axis of the head 12, the central axis of the spiral of the spring 13, the central axis of the holding portion 151, and the central axis of the central support portion 152. The central axis of the spiral of the spring 16 and the central axis of the hole 114 are arranged on the same straight line.

  The case 11 has a hole 114 having a circular cross section, and slidably accommodates a holding part 151 to which the head 12 and the center point support 152 are attached in the hole 114. . In the present embodiment, a case including a first member 111 and a second member 112 is employed as an example of the case 11. The first member 111 and the second member 112 are screwed by a screw 113. As shown in FIG. 2A, the first member 111 includes through holes 111a through which the screws 113 penetrate at four corners. Further, the second member 112 includes screw holes 112a into which the screws 113 are inserted at the four corners (positions corresponding to the through holes 111a).

  Further, the front portion 115 (one end surface) of the case 11 (first member 111) includes a circular opening 115b communicating with the hole 114, and the rear end portion (the other end) of the case 11 (second member 112). The limit switch 14 is provided on the end face of the head. That is, when detecting breakage of the tool 30, the case 11 includes a circular opening 115b in the front portion 115 which is a surface facing the tool 30 (the cutting edges 311 and 312). A limit switch 14 is provided. The limit switch 14 has a detection surface for detecting contact disposed inside the case 11 and a wiring 17 for outputting a signal to the outside is disposed outside the case 11.

  Further, as shown in FIG. 2B, the opening area of the opening 115b is the cross-sectional area of the portion of the head 12 where the thickness in the direction perpendicular to the central axis of the head 12 is the largest (this cross-sectional area is the center of the head 12). Smaller than the area of the section along the plane perpendicular to the axis). Preferably, the area is the same as the area of the contact surface 121 of the head 12 or larger than the area of the contact surface 121.

  And the hole 114 in the 1st member 111 has comprised the shape of three steps from which an opening diameter differs. First, a first region within a predetermined range from the opening 115b (for example, a thickness corresponding to half of the thickness of the head 12 in the central axis direction of the head 12 or the thickness of the head 12 in the central axis direction of the head 12). In FIG. 5, the closer to the opening 115b, the smaller the opening area and the larger the amount of change in the opening area. In this way, the hole portion 114 is formed with the drop prevention portion 115a. In other words, the first region has an opening 115b that is smaller than the cross-sectional area of the portion having the largest thickness in the direction perpendicular to the central axis of the head 12, and the side surface of the head 12 within a predetermined range from the opening 115b. A curved surface corresponding to the shape of

  Next, in a second region within a predetermined range (for example, a range in which the head 12 is moved in the direction of the central axis of the head 12) from the end of the first region (the end opposite to the opening 115b). Has a cylindrical shape having an opening area (an opening diameter that allows the head 12 to slide) that is larger than the cross-sectional area of the thickest portion in the direction perpendicular to the center axis of the head 12. In other words, the head 12 has a cylindrical shape having an opening diameter larger than the diameter of the thickest portion in the direction perpendicular to the central axis of the head 12.

  In the third region from the end of the second region (the end opposite to the first region) to the end of the first member 111 (the end opposite to the opening 115b), An opening area (open enough to allow the holding portion 151 to slide) larger than the cross-sectional area of the tip of the holding portion 151 to be described (this cross-sectional area is an area of a cross section along a plane perpendicular to the central axis of the head 12). It has a cylindrical shape having a diameter. In other words, it has a cylindrical shape having an opening diameter larger than the diameter at the tip of the holding portion 151.

  As a result, the head 12 can be displaced in the direction of the central axis of the head 12 and can easily be inclined with respect to a virtual plane perpendicular to the central axis of the head 12. Further, the contact surface 121 of the head 12 can be exposed to the outside of the case 11 through the opening 115b.

  As shown in FIG. 2B, the hole 114 in the second member 112 has a cross-sectional area of a rear end portion of the holding portion 151 described later (this cross-sectional area is perpendicular to the central axis of the head 12). It has a cylindrical shape having an opening area (opening diameter enough to allow the holding portion 151 to slide) larger than the cross-sectional area. In other words, a cylindrical shape having an opening diameter larger than the diameter at the rear end portion of the holding portion 151 is formed. In addition, as shown in FIG.2 (b), as for the holding | maintenance part 151, the cross-sectional area of a rear-end part is larger than the cross-sectional area of a front-end | tip part. Therefore, the opening area of the hole 114 in the second member 112 is larger than the opening area of the third region of the first member 111. Therefore, the case 11 has step portions between the second member 112 and the first member 111 and between the second region and the third region of the first member 111. In FIG. 1, the holding portion 151 is illustrated in a simplified manner.

  As shown in FIG. 3, the head 12 includes a circular contact surface 121 that contacts one end (tip portions 311 c and 312 c) of the tool 30, and a circular back surface 122 (parallel to the contact surface 121) that faces the contact surface 121. The columnar member is a part of a sphere having a thickest portion in the direction perpendicular to the central axis of the head 12 between the contact surface 121 and the back surface 122. It is. Therefore, the side surface 123 of the head 12 (columnar member) is a part of a spherical surface. That is, the head 12 includes the centroid of the sphere actually or virtually (when the centroid of the sphere is in the recess 124) at a position between the contact surface 121 and the back surface 122. The central axis of the head 12 passes through the center of gravity of the sphere included in the head 12. Ideally, the length of the center of gravity and the contact surface 121 on the central axis of the head 12 and the length of the center of gravity and the back surface 122 of the head 12 on the central axis are preferably the same. The contact surface 121 is in contact with the tip portions 311c and 312c at the same time when one end (tip portions 311c and 312c) of the tool 30 is in contact with the center axis of the head 12 and the center axis of the tool 30 being aligned. It has a shape.

  Further, a concave portion 124 that is a portion where the center point support portion 15 is disposed is provided on the back surface 122 side of the head 12. The concave portion 124 has a conical bottom that decreases in opening area from the back surface 122 side toward the contact surface 121 side. The center point of the recess 124 (the center point of the conical bottom) is provided on the center axis of the head 12.

  In the present embodiment, the head 12 is housed in the hole 114 as described above, can be displaced in the direction of its own central axis, and can be inclined with respect to a virtual plane perpendicular to its central axis. However, the present invention is not limited to this. In other words, the shape of the head 12 is not particularly limited as long as the head 12 can be displaced in the direction of the central axis of the head 12 and can be tilted with respect to a virtual plane perpendicular to the central axis of the head 12.

  The spring 13 is formed by processing a metal material in a spiral shape, and automatically returns the head 12 to the origin position by a restoring force. The spring 13 is disposed between the head 12 and the holding portion 151 such that its own central axis (spiral central axis) coincides with the central axis of the head 12. The origin position of the head 12 is a state in which the head 12 is not pressed from the tool 30 and a state in which the head 12 is pressed by the spring 13 to the opening 115b side (disengagement preventing portion 115a) of the case 11. This is a possible position. Here, as an example, as shown in FIGS. 1 and 2, the head 12 is not inclined with respect to a virtual plane perpendicular to the center axis of the head 12, and a part on the tip side of the head 12 is an opening of the case 11. A position protruding from the portion 115b to the outside of the case 11 is employed.

  As described above, in the present embodiment, description will be made using the spring 13 processed in a spiral shape as an elastic member as an example of the restoring force generating portion, but the present invention is not limited to this. A spring processed into a shape other than a spiral (such as a leaf spring) or an elastic member (elastic member other than a spring) formed and processed to have elasticity such as rubber or sponge can also be used. . In addition to the elastic member, the restoring force generator may be employed as long as it generates a restoring force that can automatically return the head 12 to the origin position, such as magnetism or air. However, the restoring force generator can be easily configured by using an elastic member.

  In addition, as shown in FIG. 2 (b), the holding portion 151 has a two-stage (front end portion and rear end portion) cylindrical shape, that is, two cylindrical portions having different cross-sectional areas have the same center axis. It has a continuous shape. In addition, as described above, the cross-sectional area of the rear end portion is larger than the cross-sectional area of the front end portion in the relationship between the cross-sectional areas of the front end portion and the rear end portion.

  This holding portion 151 is slidable in the central axis direction of the head 12 in the hole portion 114 of the second member 112, and is arranged so that the front end portion is on the head 12 side and the rear end portion is on the limit switch 14 side. Is done. And the holding | maintenance part 151 is a member different from the spring 13, and it is the head 12 side (between the 2nd member 112 and the 1st member 111 by the spring 16 arrange | positioned between the holding | maintenance part 151 and the limit switch 14. And a step portion between the second region and the third region of the first member 111). The spring 16 is formed by processing a metal material into a spiral shape.

  When the head 12 is not pressed by the tool 30, the holding portion 151 is pressed by the spring 16 to be between the second member 112 and the first member 111 and the first as shown in FIG. The member 111 is pressed against the step portion between the second region and the third region. Therefore, when the head 12 is not pressed by the tool 30, it is held by the step between the second member 112 and the first member 111 and between the second region and the third region of the first member 111. The distance between one end surface of the portion 151 (the surface facing the back surface 122 of the head 12) and the back surface 122 of the head 12 is maintained. That is, the step portion between the second member 112 and the first member 111 and between the second region and the third region of the first member 111 functions as a stopper of the holding portion 151.

  As shown in FIG. 2B, a center support portion 152 that supports the center of the head 12 (the center axis of the head 12) is provided at the tip of the holding portion 151. The center support portion 152 is a rod-like member, and has a shape in which a screw 152a is provided at one end and the other end (tip) is pointed. The center support portion 152 is fixed by screwing a screw 152a into a screw hole 151a provided in the center shaft at the tip of the holding portion 151. The center support part 152 supports the center of the head 12 by contacting the center of the bottom of the recess 124 provided on the back surface 122 of the head 12 while being fixed to the holding part 151 and disposed in the case 11.

  Thus, by providing the center support portion 152 that supports the center of the head 12 (the center axis of the head 12), the head 12 supports the point (the center axis of the head 12) supported by the center support portion 152. Will move as. Therefore, the head 12 is easy to return to the origin position when the head 12 is not pressed from the tool 30 after being tilted with respect to a virtual plane perpendicular to the central axis of the head 12.

  The limit switch 14 detects the moving distance that the head 12 pressed by the tool 30 moves in the central axis direction, and outputs a detection signal indicating that the head 12 has moved a predetermined distance from the origin position. The limit switch 14 contacts the head 12 indirectly (via the holding portion 151) when the head 12 moves a predetermined distance from the origin position in the center axis direction, and the head 12 moves from the origin position to the center axis direction. It is a contact type limit switch that outputs a detection signal indicating that it has moved a predetermined distance.

  Thus, the sensor 10 outputs a detection signal (ON signal) when the tool 30 pushes the head 12 from the origin position for a predetermined distance, and outputs a detection signal (ON signal) when the tool 12 does not push the head 12 for a predetermined distance from the origin position. ) Is not output. That is, the sensor 10 can be rephrased as a contact sensor that detects whether or not the tool 30 is in contact.

  Next, the breakage detection unit 20 of the breakage detection apparatus will be described with reference to FIG. The breakage detection unit 20 is configured by a computer or the like, and has a function (driving) for moving the sensor 10 from the sensor-side reference position by outputting a driving signal to a driving mechanism (not shown) that moves the sensor 10. Means) and a function (measuring means) for measuring the moving distance that the sensor 10 has moved from the sensor-side reference position until the detection signal (ON signal of the limit switch 14) is output from the sensor 10 (limit switch 14). The function of detecting whether or not the cutting edges 311 and 312 of the tool 30 are broken depending on whether or not the measured movement distance of the sensor 10 matches a preset reference distance (determination distance for breakage detection) (breakage detection) Part).

  The drive mechanism for moving the sensor 10 can include, for example, an actuator driven by hydraulic pressure or pneumatic pressure such as a hydraulic cylinder or a pneumatic cylinder. Further, the means for measuring the moving distance that the sensor 10 has moved from the sensor-side reference position is not particularly limited. The reference distance is stored in the storage unit of the breakage detection unit 20, for example. When a tool having a plurality of lengths (length from the tool side reference position to the tip of the tool 30) is to be detected, it is necessary to change the reference distance depending on the length of the tool. Therefore, the storage unit of the breakage detection unit 20 associates the length of the detection target tool 30 (the length from the tool side reference position to the tip of the tool 30) with the reference distance for each length of the tool 30. To remember.

  Here, a method for detecting the presence or absence of breakage of the tool 30 by the breakage detection apparatus including the sensor 10 and the breakage detection unit 20 will be described.

  First, the tool holder 40 and the sensor 10 holding the tool 30 removed from the main spindle device and stored in the storage unit (magazine) after the cutting process is set to a predetermined position. At this time, as shown in FIG. 1, the contact surface 121 of the head 12 in the sensor 10 and the tip portions 311 c and 312 c of the tool 30 are opposed to each other, and the central axis of the sensor 10 (head 12) and the central axis of the tool 30 are And the sensor 10 and the tool holder 40 are set at the sensor side reference position and the tool side reference position separated by a certain distance.

When the sensor 10 is set at the sensor side reference position, the front portion 115 of the sensor 10 is disposed at the sensor side reference position. On the other hand, when the tool holder 40 is set at the tool side reference position, the attachment end of the tool holder 40 when the tool holder 40 is attached to the spindle device is arranged at the tool side reference position.

  Next, the breakage detection unit 20 outputs the drive signal to the drive mechanism that moves the sensor 10 to move the sensor 10 from the sensor-side reference position to the tool 30 side until the detection signal is output from the sensor 10. . At this time, the tool 30 is in a state of being held at the tool holder 40 and fixed at the tool side reference position. Further, the breakage detection unit 20 determines whether a detection signal is output from the sensor 10 while moving the sensor 10. And until the detection signal is output from the sensor 10, the movement distance that the sensor 10 has moved from the sensor side reference position is measured.

  Next, when the breakage detection unit 20 measures the movement distance that the sensor 10 has moved from the sensor-side reference position before the detection signal is output from the sensor 10, the breakage detection unit 20 stores the measured movement distance and the storage unit in advance. Compare with the reference distance. The breakage detection unit 20 determines that the cutting edges 311 and 312 of the tool 30 are not broken (normal) when the movement distance matches a preset reference distance, and when the movement distance does not match, the cutting edge of the tool 30 It is determined that 311 and 312 are broken. By doing in this way, the presence or absence of breakage of the cutting edges 311 and 312 of the tool 30 can be detected.

  Here, the case where there is no breakage in the tool 30 to be detected will be described in comparison with the case where there is a breakage.

  First, when the tool 30 to be detected is not broken, as shown in FIG. 4B, when the head 12 is pressed by a normal tool 30 in which all the cutting edges are not broken, On the other hand, the position on the contact surface 121 that is rotationally symmetric is pressed. Reference numerals 311 c and 312 c in FIG. 4B indicate positions where the tip portions 311 c and 312 c are in contact with each other on the contact surface 121. In this way, when the head 12 is pressed by the tool 30 at a position on the contact surface 121 that is rotationally symmetric with respect to its own central axis, as shown in FIG. It is displaced to. That is, the head 12 moves parallel to the virtual plane.

  On the other hand, when the tool 30 to be detected is broken, as shown in FIG. 5B, the head 12 is pressed by the tool 30 in which only some of the cutting edges are broken. The tool 30 presses a position on the contact surface 121 that is not rotationally symmetric with respect to its own central axis. Reference numeral 311 c in FIG. 5B indicates a position on the contact surface 121 where the tip 311 c is in contact. As described above, when the head 12 is pressed by the tool 30 at a position on the contact surface 121 that is not rotationally symmetric with respect to the central axis of the head 12 (that is, the position pressed by the tool 30 is relative to the central axis of the head 12). 5), as shown in FIG. 5 (a), since it is inclined with respect to a virtual plane perpendicular to its central axis, it is difficult to move a predetermined distance from the origin position.

  That is, when the head 12 is pressed in a state where the center of the contact position of the tool 30 on the contact surface 121 and the center of the contact surface 121 coincide with each other, the head 12 can move a predetermined distance in the pressing direction. On the other hand, when the contact position of the tool 30 on the contact surface 121 is pressed in a state of being biased with respect to the center of the contact surface 121, it is inclined in a pressing direction by tilting with respect to a virtual plane perpendicular to its center axis. The movement is suppressed.

  Therefore, when the tool 30 and the head 12 are relatively moved and the head 12 is pressed with the tool 30, the head 12 is pressed with the normal tool 30, and only a part of the plurality of cutting edges is present. When the head 12 is pushed with the bent tool 30, the relative movement distance between the tool 30 and the head 12 required until the limit switch 14 outputs the detection signal can be made different. That is, in the normal tool 30 and the tool 30 in which only some of the cutting edges are bent, the movement distance by which the sensor 10 moves from the sensor-side reference position before the detection signal is output from the sensor 10. Can be different. In the case of the tool 30 in which all the cutting edges are bent, the moving distance by which the sensor 10 moves from the sensor-side reference position before the detection signal is output from the sensor 10 with respect to the normal tool 30 is also shown. Can be different. Therefore, it is possible to easily detect the presence or absence of breakage of the tool 30 provided with the plurality of cutting edges 311 and 312 at rotationally symmetrical positions at one end.

  In the present embodiment, the tool 30 is fixed, the sensor 10 is moved from the sensor-side reference position, and the presence or absence of breakage of the tool 30 is determined based on the movement distance until the detection signal is output from the sensor 10. Although an example of detection is adopted, the present invention is not limited to this. In the present invention, the sensor 10 and the tool 30 are relatively moved from the reference position, and the presence or absence of breakage of the tool 30 is detected based on the relative movement distance until the detection signal is output from the sensor 10. If so, the goal can be achieved. Therefore, the sensor 10 may be fixed and the tool 30 may be moved from the tool side reference position.

  Further, in the present embodiment, the breakage of the tool 30 is determined based on the relative movement distance until the sensor 10 and the tool 30 are relatively moved from the reference position and the detection signal is output from the sensor 10. Although a detection method for detecting the presence or absence is employed, the present invention is not limited to this. For example, in order to press the head 12 with the tool 30, the center axis of the tool 30 and the center axis of the head 12 are made to coincide with each other, and the sensor 10 and the tool 30 are set to a predetermined distance from a reference position (a normal tool). If it is 30, it is moved relatively (distance where the detection signal is output from the sensor 10) (driving means). The presence or absence of breakage of the cutting edges 311 and 312 of the tool 30 is detected based on whether or not a detection signal is output from the limit switch 14 with the sensor 10 and the tool 30 relatively moved by a preset distance. The detection method (breakage detection unit) may be adopted. In this detection method, when the sensor 10 and the tool 30 are relatively moved from the reference position by a preset distance, and the tool 30 is normal, the head 12 moves from the origin position to the central axis by a predetermined distance. Then, a detection signal is output from the limit switch 14. On the other hand, when the tool 30 is broken, the detection signal is not output from the limit switch 14 because the head 12 does not move from the origin position in the central axis direction by a predetermined distance. That is, the breakage detection unit 20 moves the sensor 10 and the tool 30 relative to each other by a predetermined distance from the reference position, and when a detection signal is output from the limit switch 14, the cutting edge 311 of the tool 30. When it is determined that 312 is not broken (normal) and no detection signal is output, it is determined that the cutting edges 311 and 312 of the tool 30 are broken. In this case, either the sensor 10 or the tool 30 may be moved.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the embodiment mentioned above at all, and various deformation | transformation are possible in the range which does not deviate from the meaning of this invention.

(Modification 1)
Next, the sensor 10a in the modification 1 is demonstrated using FIG. In addition, since the sensor 10 in the above-mentioned embodiment and the sensor 10a in the modification 1 have many common points, the common points are given the same reference numerals and the description thereof is omitted.

  In the sensor 10 of the above-described embodiment, the contact type limit switch 14 is adopted as the detection unit of the present invention, whereas in the sensor 10a of the first modification, a non-contact type limit switch (light emission) is used. The difference is that the portion 14a1 and the light receiving portion 14a2) are employed. As shown in FIG. 6, the sensor 10 a is arranged to face the case 11 through the hole 114, and emits light, and a light receiving unit 14 a 1 that emits light and a light receiving unit that receives light emitted from the light emitting unit 14 a 1. 14a2. The light emitted from the light emitting unit 14a1 is received by the light receiving unit 14a2 when the head 12 has not moved a predetermined distance from the origin position, and irradiated to the head 12 when the head 12 has moved a predetermined distance from the origin position. Will be. That is, when the head 12 moves a predetermined distance from the origin position, the light emitted from the light emitting unit 14a1 is blocked by the head 12, so that the light receiving unit 14a2 cannot receive light.

  Therefore, when the head 12 has not moved a predetermined distance from the origin position, the light receiving unit 14a2 uses a signal indicating that light is received as a signal indicating that the head 12 has not moved a predetermined distance from the origin position. Output. On the other hand, when the head 12 moves a predetermined distance from the origin position, the light receiving unit 14a2 uses a signal indicating that the head 12 has not received light as a signal (detection signal) indicating that the head 12 has moved a predetermined distance from the origin position. Output.

  As described above, even when the non-contact type limit switch (light emitting unit 14a1, light receiving unit 14a2) is employed, the moving distance that the head 12 pressed by the tool 30 moves in the central axis direction is detected. A detection signal indicating that 12 has moved a predetermined distance from the origin position can be output. Even when this sensor 10a is used, the above-described two detection methods can be employed as a method for detecting whether or not the tool 30 is broken.

(Modification 2)
Next, the sensor 10b according to Modification 2 will be described with reference to FIG. In addition, since the sensor 10 in the above-mentioned embodiment and the sensor 10b in the modification 2 have many common points, the common points are given the same reference numerals and the description thereof is omitted.

  In the sensor 10 of the above-described embodiment, the contact type limit switch 14 is employed as the detection unit of the present invention, whereas in the sensor 10b of the second modification, the distance sensor 14b1 is employed. Different. As shown in FIG. 7, the sensor 10 b is arranged on the opposite side of the front portion 115 of the case 11, and irradiates the holding portion 151 with infrared rays and reflects the infrared rays reflected by the holding portion 151. A distance sensor 14b1 for detecting the moving distance of the head 12 is provided. That is, the distance sensor 14b1 outputs a signal (a signal indicating the distance) corresponding to the moving distance from the origin position of the head 12.

  As described above, even when the distance sensor 14b1 is employed, the movement distance that the head 12 pressed by the tool 30 has moved in the central axis direction is detected, and the head 12 has moved a predetermined distance from the origin position. A detection signal can be output. Further, in the case of the distance sensor 14b1, unlike the contact type limit switch 14 or the non-contact type limit switch (the light emitting unit 14a1 and the light receiving unit 14a2), the detection indicating that the head 12 has moved a predetermined distance from the origin position. In addition to the signal, a signal indicating the moving distance of the head 12 can be output. Therefore, when this sensor 10b is used, as a detection method for detecting the presence or absence of breakage of the tool 30, the following detection methods can be adopted in addition to the two detection methods described above.

  That is, in order to press the head 12 with the tool 30, the center axis of the tool 30 and the center axis of the head 12 are made to coincide with each other, and the sensor 10b and the tool 30 are relatively moved from the reference position (driving means). . And based on the signal according to the movement distance of the head 12 output from the distance sensor 14b1, the movement distance which the sensor 10b and the tool 30 moved relatively from the reference position is measured (measurement means). And based on the measured movement distance, the presence or absence of breakage of the cutting edges 311 and 312 of the tool 30 may be detected (breakage detection unit).

  By doing in this way, when the tool 30 is normal, when the tool 30 is broken, and when it is broken, the movement distance in which the sensor 10b and the tool 30 are relatively moved according to the degree of breakage. Can be measured. Therefore, it is possible to easily detect the presence or absence of breakage of the tool 30 provided with a plurality of cutting edges at rotationally symmetric positions at one end with respect to the central axis, and to detect the degree of breakage.

(Modification 3)
Next, the sensor 10c in the modification 3 is demonstrated using FIG. In addition, since the sensor 10 in the above-mentioned embodiment and the sensor 10c in the modification 3 have many common points, the common points are given the same reference numerals and description thereof is omitted.

  In the sensor 10 of the above-described embodiment, the center support portion 152 that supports the center of the head 12 (the center axis of the head 12) and the holding portion 151 that holds the center support portion 152 are provided. The sensor 10c of Example 3 is different in that the holding portion 151 and the center support portion 152 are not provided. Further, since the center support portion 152 is not provided as described above, the head 12c does not need to include the recess 124 unlike the head 12 in the above-described embodiment. Thus, even if the sensor 10c does not include the holding portion 151 and the center support portion 152, the object of the present invention can be achieved.

  In this case, when the head 12c moves a predetermined distance from the origin position in the central axis direction, the limit switch 14 directly contacts the head 12c, and the head 12c moves from the origin position to the central axis direction by a predetermined distance. A detection signal indicating that this has occurred is output. Further, in the sensor 10c, the non-contact type limit switches (light emitting unit 14a1 and light receiving unit 14a2) shown in the above-described modification 1 and the distance sensor 14b1 shown in the modification 2 can be employed. Therefore, even if this sensor 10c is used, the three detection methods shown in the above-described embodiment and modification 2 can be adopted as a method for detecting whether the tool 30 is broken or not. .

(Modification 4)
Next, the sensor 10d according to Modification 4 will be described with reference to FIG. In addition, since the sensor 10c in the above-described modification 3 and the sensor 10d in the modification 4 have many common points, the common points are denoted by the same reference numerals and description thereof is omitted.

  The sensor 10c according to the third modification includes the single limit switch 14 that detects whether or not the head 12c has moved a predetermined distance from the origin position in the central axis direction. Is different in that it includes a plurality of contact-type limit switches 14d1 to 14d4 (here, four examples are adopted). The head 12d is different from the sensor 10c of Modification 3 in that the back surface 122d includes a plurality of protrusions 122d1 to 122d4 (here, an example including four) is employed. The limit switches 14d1 to 14d4 and the protrusions 122d1 to 122d4 are not limited to four each. If the number of limit switches and protrusions is the same and multiple, the object can be achieved.

  That is, as shown in FIGS. 9A and 9B, the sensor 10 d is a part that is pressed by one end of the tool 30, and is in the direction of its center axis with respect to the origin position that is not pressed by the tool 30. Head 12d supported so as to be tiltable with respect to a virtual plane perpendicular to its central axis, spring 13 for automatically returning head 12d to the origin position, and head pressed by tool 30 A plurality of contact-type limit switches 14d1 to 14d4 that output a detection signal indicating that the head 12d has touched and the head 12d has moved a predetermined distance from the origin position when 12d has moved in the central axis direction from the origin position. Is provided.

  Further, as shown in FIG. 9C, the plurality of protrusions 122d1 to 122d4 are rotationally symmetric with respect to the center position of the head 12d on the back surface 122d facing the contact surface with which one end of the tool 30 in the head 12d contacts. Is provided. As shown in FIG. 9B, the plurality of contact-type limit switches 14d1 to 14d4 are provided at positions corresponding to (opposed to) the plurality of protrusions 122d1 to 122d4.

  In this way, when the head 12d is pressed with a normal tool 30, detection signals are output from all the limit switches 14d1 to 14d4, and the tool 30 in which only some of the cutting edges are broken. When the head 12d is pushed, detection signals are output only from some of the limit switches (any of 14d1 to 14d4). Therefore, when the head 12d is pressed with the normal tool 30, and when the head 12d is pressed with the tool 30 in which only some of the cutting edges are broken, the limit switches 14d1 to 14d output detection signals. The number of 14d4 can be changed. In other words, the mode of the detection signal can be changed. Therefore, it is possible to easily detect the presence or absence of breakage of the tool 30 provided with a plurality of cutting edges at rotational symmetry positions with respect to the central axis at one end.

  In addition, when this sensor 10d is used, it is preferable to employ a detection method as described below as a detection method for detecting the presence or absence of breakage of the tool 30.

  First, in order to press the head 12d with the tool 30, the center axis of the tool 30 and the center axis of the head 12d are matched, and the sensor 10d and the tool 30 are relatively moved from the reference position (driving means). . The tool 30 is based on the number of limit switches 14d1 to 14d4 that output detection signals among the plurality of limit switches 14d1 to 14d4 in a state where the sensor 10d and the tool 30 are relatively moved by a preset distance. The presence or absence of breakage of the blade edge is detected (breakage detection unit). That is, when detection signals are output from all the limit switches 14d1 to 14d4, it is determined that the cutting edge of the tool 30 is not broken and is normal, and is detected only from some limit switches (any of 14d1 to 14d4). When the signal is output, it is determined that the cutting edge of the tool 30 is broken.

  In this way, when the head 12d is pressed with a normal tool 30, detection signals are output from all the limit switches, and the pressed portion is a tool in which only some of the cutting edges are broken. When is pressed, a detection signal is output from some limit switches. Therefore, the number of limit switches that output detection signals when the pressed part is pressed with a normal tool and when the pressed part is pressed with a tool in which only some of the cutting edges are broken. Can be changed. In other words, the mode of the detection signal can be changed. Therefore, it is possible to easily detect the presence or absence of breakage of the tool 30 provided with a plurality of cutting edges at rotational symmetry positions with respect to the central axis at one end.

  10, 10a to 10d sensor, 11 case, 111 first member, 111a through hole, 112 second member, 112a screw hole, 113 screw, 114 hole portion, 115 front portion, 115a drop prevention portion, 115b opening portion, 12, 12c, 12d Head (pressed portion), 121 Contact surface, 122, 122d Back surface, 122d1-122d4 Protrusion, 123 Side surface, 124 Recess, 13 Spring (restoring force generating portion), 14, 14d1-14d4 Limit switch (detecting portion) , 14a1 Light emitting part, 14a2 Light receiving part, 14b1 Distance sensor, 151 Holding part, 151a Screw hole, 152 Center support part, 152a Screw, 16 Spring, 17 Wiring, 20 Breakage detecting part, 30 Tool, 311 312 Cutting edge, 311a, 312a Inclined portion, 311b, 312b Side wall portion, 311 , 312c Tip, 321, 322 Valley, 331, 332 Coolant hole, 341, 342 Stepped portion, 40 Tool holder, 50 Work piece, 51 Drilling hole, 52 Mountain, 53 Inclined, 54 Valley, 55 Through hole

Claims (13)

A sensor for a breakage detection device for detecting whether or not a tool edge has a breakage in a tool having a shape in which a plurality of cutting edges are provided at one end in a rotationally symmetric position with respect to the center axis and the cutting edge projects in the direction of the center axis. There,
It is a part that is pressed by one end of the tool, and can be displaced in the direction of its own central axis with respect to the origin position that is not pressed by the tool, and can be tilted with respect to a virtual plane perpendicular to its central axis A pressed part supported by
A restoring force generator that automatically returns the pressed portion to the origin position;
A detection unit that detects a movement distance that the pressed part that is pressed by the tool has moved in the direction of the central axis and that outputs a detection signal indicating that the pressed part has moved a predetermined distance from the origin position; A sensor for a breakage detection device.   It has a hole with a circular cross section, and includes a case that slidably accommodates the pressed part in the hole, and the pressed part has a circular contact surface with which one end of the tool contacts And a columnar member having both ends of a circular back surface facing the contact surface, and the columnar member is a portion having the thickest thickness in the direction perpendicular to the central axis between the contact surface and the back surface. The sensor for a breakage detection device according to claim 1, wherein the sensor is a part of a sphere having a shape.   The sensor for a breakage detection device according to claim 1, wherein the restoring force generation unit is made of an elastic member.   The detection unit is configured such that when the pressed part moves a predetermined distance from the origin position, the pressed part directly or indirectly contacts, and the pressed part moves a predetermined distance from the origin position. The sensor for breakage detection devices according to claim 1, further comprising a contact-type limit switch that outputs a detection signal indicating   The detection unit includes a non-contact limit switch that outputs a signal indicating that the pressed part has moved a predetermined distance from the origin position when the pressed part has moved a predetermined distance from the origin position. The sensor for breakage detection devices according to any one of claims 1 to 3.   The breakage detection device according to any one of claims 1 to 3, wherein the detection unit includes a distance sensor that outputs a signal corresponding to a moving distance of the pressed portion from the origin position. Sensor. A sensor for a breakage detection device that detects the presence or absence of breakage of a cutting edge of a tool provided with a plurality of cutting edges at a rotationally symmetrical position with respect to the central axis at one end,
It is a part that is pressed by one end of the tool, and can be displaced in the direction of its own central axis relative to the origin position that is not pressed by the tool, and can be tilted with respect to a virtual plane perpendicular to its central axis A pressed part supported by
A restoring force generator that automatically returns the pressed portion to the origin position;
When the pressed part pressed by the tool moves a predetermined distance from the origin position in the central axis direction, the pressed part comes into contact and the pressed part moves a predetermined distance from the origin position. A detection unit including a plurality of contact-type limit switches that output a detection signal indicating,
The pressed portion has a plurality of protrusions at rotationally symmetric positions with respect to its center position on the back surface facing the contact surface with which one end of the tool contacts.
The plurality of limit switches are provided at positions opposed to the plurality of protrusions.   It has a hole with a circular cross section, and includes a case that slidably accommodates the pressed part in the hole, and the pressed part has a circular contact surface with which one end of the tool contacts And a columnar member having both ends of a circular back surface facing the contact surface, and the columnar member is a portion having the thickest thickness in the direction perpendicular to the central axis between the contact surface and the back surface. The sensor for a breakage detection device according to claim 7, wherein the sensor is a part of a sphere having a shape.   The sensor for a breakage detection device according to claim 7 or 8, wherein the restoring force generating portion is made of an elastic member. A sensor for a breakage detection device according to any one of claims 1 to 6,
In order to press the pressed portion with the tool, the driving means moves the sensor and the tool relatively from a reference position by matching the central axis of the tool with the central axis of the pressed portion. When,
Measuring means for measuring a moving distance in which the sensor and the tool are relatively moved from a reference position before a detection signal is output from the detection unit;
A breakage detecting unit that detects whether or not the blade edge is broken depending on whether or not the moving distance measured by the measuring means matches a preset reference distance;
A breakage detection device comprising: A sensor for a breakage detection device according to any one of claims 1 to 6,
In order to press the pressed part with the tool, the center axis of the tool and the central axis of the pressed part are matched, and the sensor and the tool are relative to each other by a predetermined distance from a reference position. Driving means for moving automatically,
In a state where the sensor and the tool are relatively moved by a preset distance, a breakage detection unit that detects the presence or absence of breakage of the cutting edge depending on whether a detection signal is output from the detection unit;
A breakage detection device comprising: A sensor for a breakage detection device according to claim 6;
In order to press the pressed portion with the tool, the driving means moves the sensor and the tool relatively from a reference position by matching the central axis of the tool with the central axis of the pressed portion. When,
Based on a signal corresponding to the movement distance output from the detection unit, measuring means for measuring the movement distance that the sensor and the tool have moved relative to a reference position;
On the basis of the moving distance measured by the measuring means, a breakage detection unit that detects the presence or absence of breakage of the cutting edge,
A breakage detection device comprising: A sensor for a breakage detection device according to any one of claims 7 to 9,
In order to press the pressed portion with the tool, the driving means moves the sensor and the tool relatively from a reference position by matching the central axis of the tool with the central axis of the pressed portion. When,
With the sensor and the tool relatively moved by a preset distance, the presence or absence of breakage of the cutting edge is detected based on the number of limit switches that output detection signals among the plurality of limit switches. A breakage detection unit,
A breakage detection device comprising:

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