JP2006062061A - Tool position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool position detecting device capable of accurately measuring a position in a length direction of a tool.
SOLUTION: A main body 1a, a slide portion 4 provided from the main body 1a so as to be able to advance and retreat with respect to the main body 1a, and having a measurement surface 4a with which the tool comes into contact with the extended end surface, and the slide portion 4 are provided. Coil spring 11 that urges the measuring surface 4a toward the measuring surface 4a, and a movement detecting means that detects the movement of the slide portion 4 when the sliding portion 4 moves against the urging force of the coil spring 11, and the size of the measuring surface 4a Is the tool position detecting device 1 which is not more than the size of the cross section substantially perpendicular to the advancing / retreating direction of the slide portion 4.
[Selection] Figure 1

Description

  The present invention relates to a tool position detection device for measuring a position in a length direction of a cutting tool or the like in a machine tool or the like.

  Conventionally, in machine tools such as milling and machining centers, it has been necessary to know the position of the cutting edge of the tool attached to the spindle relative to the workpiece, and there are various tool position detection devices for that purpose. Are known. For example, there is a tool position detection device that detects contact with a workpiece by a touch sensor or the like attached to a spindle of a machine tool.

  As such a tool position detecting device, for example, a slide part (contact body) that is slidable downward and protruded by being urged upward is provided on the upper part of the housing. A flat body parallel to the bottom surface of the housing and having a tapered hole in the same direction as the sliding direction of the slide portion, a conical free conductor fitted into the tapered hole, and a small-diameter side protruding end of the free conductor A switch having a mounted electrical contact is housed in the housing, and the electrical contact is urged in a protruding direction so as to be retractable from the lower end of the slide portion with a predetermined interval. In some embodiments, the electrical contact is electrically connected to the slide portion via a series-connected energization detecting element and a power source. (For example, refer to Patent Document 1).

  In addition, it consists of a shank part gripped by the chuck and a slide part (disc for detection) provided coaxially with this shank part, and detects the coordinate position of the tool in the -X direction or + X direction on this slide part. A tool position detecting device including a −X direction and + X direction abutting portion to be detected and a −Z direction and + Z direction abutting portion for detecting a coordinate position of the tool in the −Z direction or the + Z direction is also introduced. (For example, refer to Patent Document 2).

Further, a base portion having a reference bottom surface, a head portion, a reference bottom surface, a slide portion (elevating ram) biased upward by a spring, a light emitter, and a detecting means for detecting movement of the slide portion And a tool position detection device including a light emission control circuit unit. In this tool position detection apparatus, the detection means includes a movable pin extending in the horizontal direction orthogonal to the ascending / descending direction of the slide portion and a fixed pin extending in the horizontal direction orthogonal to the movable pin, and each of the movable pin and the fixed pin has a longitudinal center. The shaft center of the slide portion is located on the crossing point of the central portion and is normally constituted by an electrical contact in which the movable pin comes into contact with the fixed pin by the biasing force of the spring. (For example, refer to Patent Document 3).
Japanese Utility Model Publication No. 63-144154 Japanese Utility Model Publication No. 6-3551 Utility Model Registration No. 3025183

  The above-described conventional tool position detecting device holds the slide portion upward by an urging force such as a spring, and when measuring the position of the tool, a measurement surface (reference bottom surface) formed on the upper portion of the slide portion. The tool is brought into contact with the tool from the vertical direction and the slide part is pressed by applying a predetermined load to measure the position of the tool in the length direction. In order to detect (measure), the measurement surface is made as large as possible. Therefore, when the tool comes into contact with the vicinity of the end portion (outer periphery) of the measurement surface and presses the slide portion, the slide portion may be tilted, resulting in a measurement error.

  Therefore, the present invention has an object to improve such a conventional tool position detecting device, and provides a tool position detecting device capable of accurately measuring the position in the length direction of the tool. For the purpose.

  In order to achieve this object, the present invention includes a main body, a slide portion that is provided so as to extend from the main body and be movable back and forth with respect to the main body, and has a measurement surface on which the tool comes into contact with the extended end surface. An urging member for urging the slide portion toward the measurement surface; and a movement detecting means for detecting the movement when the slide portion moves against the urging force of the urging member; And a tool position detecting device in which the size of the measurement surface is equal to or smaller than the size of a cross section substantially perpendicular to the advancing and retreating direction of the slide portion.

  In the tool position detecting device having this configuration, since the size of the measurement surface is equal to or smaller than the size of the cross section substantially perpendicular to the advancing / retreating direction of the slide portion, Even if it contacts the vicinity of the end (outer periphery) of the measurement surface and presses the slide portion, the slide portion can be prevented from being inclined. Therefore, the position in the length direction of the tool can be accurately detected.

  Moreover, the tool position detection apparatus concerning this invention can set the difference of the setting pressure of the said urging | biasing member, and the weight of the said slide part to 0.3 N or less.

  Here, as the diameter of the tool becomes smaller, the breakage load becomes smaller. However, in the conventional tool position detection device, the slide part provided with the measurement surface is securely held upward so that the slide part is biased. The energizing force was set to be large. Therefore, even when detecting the position of a small-diameter tool whose diameter is 0.1 mm or less, the slide portion can be moved unless a load larger than the breakage load of the tool is applied to the measurement surface. Actually, it was difficult to detect the position in the length direction of a small-diameter tool having a diameter of 0.1 mm or less.

  Therefore, in the present invention, by setting the difference between the set pressure of the urging member and the weight of the slide portion to 0.3 N or less, the tool whose position is to be detected is a small diameter tool ( For example, even if the diameter is 0.1 mm or less, the position in the length direction can be accurately detected without providing support to the tool.

  And the tool position detection apparatus concerning this invention can provide a collar part in the outer periphery of the said measurement surface. By doing in this way, in addition to the said advantage, it can prevent that a chip, cutting water, etc. penetrate | invade between a main body and a slide part.

  Moreover, the tool position detection apparatus concerning this invention can also provide a bellows-like elastic body cover between the said main body and the part extended from the said main body of the said slide part. By configuring in this way, in addition to the above-mentioned advantages, it is possible to further prevent chips and cutting water from entering between the main body and the slide portion without causing support for the forward and backward movement of the slide portion. Can do.

  In addition, the elastic body cover may be arranged on the main body side with respect to the flange portion, and the size of the elastic body cover may be equal to or less than the size of the flange portion. By configuring in this way, in addition to the above advantages, chips and cutting water are not directly applied between the main body and the portion of the slide portion that extends from the main body. Can be prevented from being deposited. Therefore, it is possible to prevent the slide portion from causing malfunction.

  Furthermore, the tool position detecting device according to the present invention includes a lubricant holder that holds a lubricant on at least one of a sliding surface of the main body with the slide portion and a sliding surface of the slide portion with the main body. The part can be formed. By doing in this way, in addition to the said advantage, the sliding resistance which arises in the case of a forward / backward movement of a slide part can be reduced.

  In the tool position detection device according to the present invention, since the size of the measurement surface is equal to or less than the size of the cross section substantially perpendicular to the advancing / retreating direction of the slide portion, the tool is temporarily detected when detecting the position of the tool. Even if the slide portion is pressed against the end (outer periphery) of the measurement surface, the slide portion can move forward and backward without being inclined. As a result, the position of the tool in the length direction can be accurately detected.

  Next, a tool position detection apparatus according to a preferred embodiment of the present invention will be described with reference to the drawings. In addition, embodiment described below is the illustration for demonstrating this invention, and this invention is not limited only to these embodiment. Therefore, the present invention can be implemented in various forms without departing from the gist thereof.

  1 is a front view of a tool position detecting apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1, and FIG. 3 is a line III-III shown in FIG. 4 is a bottom view of the tool position detecting device shown in FIG. 1, FIG. 5 is a plan view of the tool position detecting device shown in FIG. 1, and FIG. 6 is a tool position detecting device shown in FIG. FIG. 7 is a connection diagram of the light emission control circuit of the tool position detecting device shown in FIG.

  As shown in FIGS. 1-7, the tool position detection apparatus 1 concerning this Embodiment advances and retracts the base part 2 which has the flat reference | standard bottom face 2a, and the electroconductive slide part 4 formed in the substantially cylindrical shape. A main body 1a integrally formed in a substantially cylindrical shape by a head portion 3 that can be held (movable up and down) and an intermediate member 5 made of an insulating material, can extend from the head portion 3 and can move forward and backward with respect to the head portion 3. And a slide part 4 provided on the head.

  Three magnets 6 are embedded in the base portion 2 at positions shifted from each other by 120 degrees. For example, the magnets are attracted to the surface of a machine tool table, chuck or workpiece, and the reference bottom surface 2a is attached to the surface. It comes to adhere closely. A cylindrical support member 7 made of an insulating material is fitted to the base portion 2 on the upper side. The support member 7 may be formed integrally with the intermediate member 5 or may be formed separately from the intermediate member 5.

  In addition, a battery 16 is accommodated in the cylindrical support member 7 fitted in the base portion 2, and the battery 16 is connected to the reference bottom surface 2 a side (hereinafter referred to as “reference bottom surface 2 a”) of the base portion 2. The side 17 can be replaced by removing the cap 17 that is screwed to the “lower” and the “opposite side of the reference bottom 2 a side”. Further, a printed circuit board 10 described in detail later is fixed to the upper end portion of the support member 7 on the base portion 2 side.

  A fitting hole 3a is formed in the center of the head part 3 so as to be orthogonal to the reference bottom surface 2a of the base part 2, and a slide part 4 is provided along the coaxial core on the upper side of the fitting hole 3a. A bearing member 8 is slidably guided so as to be able to advance and retreat (movable up and down). A cylindrical support member 9 made of an insulating material is fitted on the lower side of the fitting hole 3a. Similarly to the support member 7, the support member 9 may be formed integrally with the intermediate member 5 or may be formed separately from the intermediate member 5. A fixing pin 13, which will be described later in detail, is fixed to the support member 9 with both ends thereof being inserted. In the head portion 3, a light emitting diode 18 as a light emitter is disposed so as to be visible from the outside, and a light emission control circuit portion 19 described in detail later is disposed in the recess 3b.

  The slide portion 4 has a measurement surface 4a parallel to the reference bottom surface 2a at the upper end, and between the lower end portion of the slide portion 4 and the printed circuit board 10 fixed to the upper end portion of the support member 7 on the base portion 2 side. A conductive compression coil spring 11 that biases the slide portion 4 upward is interposed in the gap. The lower end portion of the coil spring 11 is connected to a connection electrode 20 (see FIG. 7) provided in the peripheral portion of the printed circuit board 10. A connecting electrode 21 (see FIG. 7) for taking out the negative electrode of the battery 16 is provided at the center of the printed circuit board 10, and a connecting electrode 22 (see FIG. 7) for taking out the positive electrode of the battery 16 is provided at the base. Arranged on the inner peripheral side of the upper end of the portion 2.

  The size of the measurement surface 4a is formed to be equal to or less than the size of the substantially cylindrical slide portion 4. Specifically, as shown in FIG. 5, the measurement surface 4 a has a substantially circular shape in plan view, and the area of the measurement surface 4 a is a cross section perpendicular to the advancing / retreating direction (axial core P direction) of the slide portion 4. It is formed to be as follows.

  Further, a flange 4b concentric with the measurement surface 4a is formed on the outer periphery of the measurement surface 4a. The flange 4b functions to prevent, for example, chips and cutting water from entering between the head portion 3 and the slide portion 4 during operation. And the measurement surface 4a is formed in the state which protruded rather than the collar part 4b.

  The slide portion 4 is provided with a conductive movable pin 12 extending in the horizontal direction perpendicular to the advancing and retreating direction so as to penetrate the slide portion 4 in the diameter direction and integrally therewith. A guide hole 14 that penetrates in the diameter direction of the slide portion 4 and extends along the axis P of the slide portion 4 is formed in a substantially intermediate portion of the slide portion 4 in the advancing and retreating direction. A conductive fixing pin 13, which is positioned above the movable pin 12 and extends in the horizontal direction with respect to the movable pin 12, is slidably inserted into the guide hole 14.

  The movable pin 12 and the fixed pin 13 cross each other at the center in the longitudinal direction, and the axis P of the slide portion 4 is located on the center crossing point Q. The movable contact 12 forms an electrical contact 15 that comes into contact with the fixed pin 13. As will be described in detail later, when the tool contacts the measurement surface 4a of the slide portion 4, the electrical contact 15 The movement detecting means for detecting the movement of the slide part 4 is configured.

  Further, between the lower part of the flange part 4 b of the slide part 4 and the upper surface of the head part 3, one end is fixed to the lower part of the flange part 4 b of the slide part 4 and the other end is the upper surface of the head part 3. An accordion-shaped elastic cover 30 fixed near the fitting hole 3a is provided. The elastic body cover 30 is formed so that its size is equal to or smaller than the size of the flange portion 4b. The elastic body cover 30 can expand and contract the bellows part following the forward / backward movement of the slide part 4, so that there is no support for the forward / backward movement of the slide part 4. It is possible to prevent chips and cutting water from entering between. Moreover, since it is covered with the collar part 4b, a chip, cutting water, etc. do not apply directly. Therefore, it is possible to prevent chips from accumulating, and it is possible to prevent the slide portion from causing malfunction. In the present embodiment, a rubber elastic body cover 30 is used.

  Further, a groove 31 is formed on the outer peripheral surface of the slide portion 4 as a lubricant holding portion for holding the lubricant. Then, by holding the lubricant in the groove 31, the sliding resistance generated when the slide portion 4 moves forward and backward can be reduced, and the slide portion 4 can be smoothly advanced and retracted.

  As shown in FIG. 6, the light emission control circuit unit 19 of the light emitting diode 18 includes a circuit in which an electrical contact 15 and a resistor 24 are connected in series, a transistor 23 as a switching element, a resistor 25, and a light emitting diode 18 as a light emitter. The connected circuit is connected in parallel, the positive electrode of the battery 16 is connected to the electrical contact 15 and the transistor 23, the negative electrode of the battery 16 is connected to the resistor 24 and the light emitting diode 18, and the base of the transistor 23 is connected to the electrical contact 15 and the resistor. 24 midpoints are connected.

  Reference numeral 23 is a transistor as a switching element, reference numeral 24 is a resistor having a high resistance value of, for example, about 330 KΩ, and reference numeral 25 is a resistor having a low resistance value of, for example, about 220Ω. Reference numerals 26a to 26e are connection terminals, and reference numeral 27 is a circuit board.

  Specifically, as shown in FIG. 7, the connection electrode 22 and the connection electrode 20 are connected to the connection terminal 26a, the fixing pin 13 of the electrical contact 15 is connected to the connection terminal 26c, the connection electrode 21 is connected to the connection terminal 26d, and The light emitting diode 18 is connected to the connection terminal 26b and the connection terminal 26e, respectively.

  Of the advancing and retreating movements of the slide part 4, when the measurement surface 4a is pressed and moved (down) in the direction in which the slide part 4 is inserted into the head part 3, the force pressing the measurement surface 4a is a coil spring. This is done when the force of 11 is resisted. Here, the tool position detection apparatus 1 according to the present embodiment is set so that the difference between the set pressure of the coil spring 11 and the weight of the slide portion 4 is 0.3 N or less.

  The tool position detection device 1 configured as described above uses, for example, the magnet 6 disposed on the reference bottom surface 2a to attract the tool attached to the machine tool to the measurement surface 4a, for example, by attracting it to the surface or side surface of the workpiece. The position in the longitudinal direction of the tool is detected by making it approach from the vertical direction and abut against it.

  That is, when the tool comes into contact with the measurement surface 4 a of the slide part 4, the slide part 4 starts to descend and the electrical contact 15 is opened. As a result, it is applied to the base of the transistor 23 via the electrical contact 15. In addition, the positive voltage of the battery 16 decreases instantaneously. Along with this, the transistor 23 becomes conductive, a predetermined current flows to the light emitting diode 18 through the protective resistor 25, and the light emitting diode 18 emits light. Further, when the opening process of the electrical contact 15 is viewed in detail, it is gradually opened, and the base voltage of the transistor 23 gradually decreases. However, the transistor 23 is instantaneous when the base voltage reaches a predetermined voltage. Since it conducts, the light emitting diode 18 always emits light when the electrical contact 15 is in a constant open state.

  In this way, when the tool comes into contact with the measurement surface 4a of the slide portion 4, the light emitting diode 18 is lit brightly at that moment, and the lighting timing is clear. There is no difference, and the generation of measurement errors due to it is eliminated. In the closed state of the electrical contact 15, a current always flows through the resistor 24. However, since the resistance value of the resistor 24 is as large as about 330 KΩ, the consumption of the battery 16 can be reduced.

  Further, when the opening / closing operation of the electrical contact 15 is mechanically viewed, the electrical contact 15 is composed of the above-described movable pin 12 and the fixed pin 13 extending in the horizontal direction with respect to the movable pin 12 above the movable pin 12. The movable pin 12 and the fixed pin 13 cross each other at the center in the longitudinal direction, and the axis P of the slide portion 4 is located on the center crossing point Q. Since the movable pin 12 is configured to come into contact with the fixed pin 13 by the urging force, the movable pin 12 is always at the center crossing point Q on the axis P of the slide portion 4 with respect to the fixed pin 13. In contact. Further, when a load of 0.3 N or less is applied to the measurement surface 4 a, the slide part 4 is lowered and the movable pin 12 is separated from the fixed pin 13. Accordingly, it is possible to perform an accurate opening / closing operation corresponding to the movement of the electrical contact 15 and the slide portion 4 and to perform highly accurate detection.

  At this time, since the area of the measurement surface 4a is formed to be equal to or smaller than the cross section perpendicular to the axial direction (advance / retreat direction) of the slide portion 4, a tool is temporarily placed near the outer periphery of the measurement surface 4a. Even if they come into contact with each other, the slide portion 4 does not tilt and enters the fitting hole portion 3a of the head portion 3, so that detection with higher accuracy can be performed.

  Next, using the tool position detection device 1 according to the present embodiment, as a small-diameter tool, a small-diameter drill having the diameter shown in Table 1 is loaded with a load at the time of breakage and a slide portion until breakage by the following method. The actual movement amount of 4 was measured.

  First, an electronic balance in units of 0.1 g is placed on the table of the machining center, and the tool position detecting device 1 is placed on the electronic balance. Next, each of the four types of small-diameter drills shown in Table 1 is individually clamped to the spindle of the machining center, and the small-diameter drill breaks in 0.001 mm increments on the measurement surface 4a of the tool position detecting device 1 Keep pushing until you do. The value (load at breakage) indicated by the electronic balance when the small-diameter drill breaks and the actual movement amount from the time when the small-diameter drill contacts the measurement surface 4a of the tool position detecting device 1 to the breakage are read. The results are shown in Table 1.

  In addition, the set load of the tool position detection apparatus 1 was 30 g, and a small diameter drill was a super micro drill (carbide Vio coating) manufactured by Ryoko Seiki Co., Ltd.

  From Table 1, in the case of a small-diameter drill having a diameter of 0.05 mm, it was confirmed that breakage occurred when a load of 75.6 g (about 0.74 N) was applied. The tool position detection device 1 according to the present invention is configured such that the slide portion 4 descends (moves) against the biasing force of the coil spring 11 when the measurement surface 4a is pressed with a load of 0.3 N or less. Therefore, it can be seen that the position in the length direction can be measured even with a small diameter drill having a diameter of 0.05 mm.

  In the present embodiment, the case where the groove 31 as the lubricant holding portion for holding the lubricant is formed on the outer peripheral surface of the slide portion 4 is described. However, the present invention is not limited to this, and the groove 31 is formed in the head portion 3. (In this embodiment, the bearing member 8) may be formed on the sliding surface with the slide portion 4, and the sliding surface with the head portion 3 of the slide portion 4 (in this embodiment, the bearing member 8). And may be formed on both of the sliding surfaces of the head portion 3 (the bearing member 8 in the present embodiment) and the slide portion 4.

  In the present embodiment, the case where the flange portion 4b is formed on the outer periphery of the measurement surface 4a has been described. However, the present invention is not limited to this, and for example, as shown in FIGS. The part 4b may not be formed.

  Further, as another configuration for disposing the flange portion 4b on the outer periphery of the measurement surface 4a, the flange portion 4b is fixedly disposed on the head portion 3, and an opening formed in the center portion of the flange portion 4b. An example is a configuration in which the measurement surface 4a is exposed from the portion and can be moved back and forth with respect to the flange portion 4b.

  In the present embodiment, the case where the measurement surface 4a is formed so as to protrude from the flange 4b has been described. However, the present invention is not limited thereto, and the measurement surface 4a and the flange 4b can be distinguished. For example, the measurement surface 4a may be concave with respect to the flange 4b, or may be flush.

  Furthermore, although the case where the coil spring 11 is used as the biasing member that biases the slide portion 4 has been described in the present embodiment, the present invention is not limited thereto, and the biasing member biases the slide portion 4. If possible, other members may be used.

  In the present embodiment, the case where the electric contact 15 including the movable pin 12 and the fixed pin 13 is used as the movement detection unit has been described. Other configurations may be provided as long as the movement can be detected.

It is a front view of the tool position detection apparatus concerning an embodiment of the invention. It is sectional drawing along the II-II line | wire shown in FIG. It is sectional drawing along the III-III line | wire shown in FIG. It is a bottom view of the tool position detection apparatus shown in FIG. It is a top view of the tool position detection apparatus shown in FIG. It is a light emission control circuit diagram of the tool position detection apparatus shown in FIG. It is a connection diagram of the light emission control circuit of the tool position detection apparatus shown in FIG. It is a front view of the tool position detection apparatus concerning other embodiment of this invention. It is sectional drawing along the IX-IX line shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tool position detection apparatus 1a Main body 2 Base part 3 Head part 4 Slide part 4a Measurement surface 4b Gutter part 5 Intermediate member 11 Coil spring 30 Elastic body cover 31 Groove

Claims (6)

The body,
A slide portion extending from the main body and provided so as to be movable back and forth with respect to the main body, and having a measurement surface with which the tool comes into contact with the extended end surface;
A biasing member that biases the slide portion toward the measurement surface;
A movement detecting means for detecting the movement when the slide portion moves against the urging force of the urging member;
With
The tool position detection apparatus whose size of the said measurement surface is below the magnitude | size of the cross section substantially perpendicular | vertical to the advancing / retreating direction of the said slide part.   The tool position detecting device according to claim 1, wherein a difference between a set pressure of the urging member and a weight of the slide portion is set to 0.3 N or less.   The tool position detecting device according to claim 1 or 2, wherein a flange portion is provided on an outer periphery of the measurement surface.   The tool position detecting device according to any one of claims 1 to 3, wherein a bellows-like elastic body cover is provided between the main body and a portion of the slide portion extending from the main body.   The tool position detection device according to claim 4, wherein the elastic body cover is disposed closer to the main body than the collar portion, and the size of the elastic body cover is equal to or less than the size of the collar portion. 6. A lubricant holding portion for holding a lubricant is formed on at least one of a sliding surface of the main body with the slide portion and a sliding surface of the slide portion with the main body. The tool position detection apparatus as described in any one of these.

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