JP2015219154A - Dimension measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimension measuring device for accurately detecting external diameter of a workpiece.SOLUTION: A dimension measuring device comprises: a body part 42 having a first fulcrum 52 and a second fulcrum 54; a first feeler 44 supported to the first fulcrum 52 so as to oscillate freely, contacting an outer peripheral surface of a workpiece W at one end side, and oscillating according to displacement of external diameter of the workpiece W; a second feeler 45 supported to the second fulcrum 54 so as to oscillate freely, contacting the outer peripheral surface of the workpiece W at one end side, and oscillating according to displacement of external diameter of the workpiece W; a first detector 46 disposed on the body part 42 and first feeler 44 on an opposite side of one end side, to the first fulcrum 52, detecting a relative position of the body part 42 and the first feeler 44, and having an arc detection locus whose center is the first fulcrum 52; and a second detector 47 disposed on the body part 42 and the second feeler 45 on an opposite side of one end side, to the second fulcrum 54, detecting a relative position of the body part 42 and the second feeler 45, and having an arc detection locus whose center is the second fulcrum 54.

Description

  The present invention relates to a dimension measuring apparatus applicable to a machine tool such as a grinding machine.

  Conventionally, in a machine tool such as a grinding machine or a lathe, the outer diameter of the workpiece being measured is measured in parallel with the machining of the outer peripheral surface of the workpiece, and the machine tool performs machining while feeding back the measurement result. There is a measuring device technology. For example, in the dimension measuring apparatus shown in Patent Document 1, a workpiece is interposed between measurement terminals provided at one end portions of a pair of feelers whose both ends can swing with respect to a fulcrum. In such a state, when the outer periphery of the workpiece is machined, for example, when it changes in the small diameter direction, the distance between the one ends of the pair of feelers changes so that the distance between the other ends expands around the fulcrum. To change.

  At this time, each of the other end portions is displaced around the fulcrum, so that an arc-shaped locus is drawn. The amount of the change is measured by a displacement measuring unit provided on each other end of the pair of feelers, and the outer diameter of the workpiece is calculated from the measurement result. Specifically, the displacement measuring unit is arranged in a cylindrical operating transformer provided at the other end of one feeler and the other end of the other feeler disposed in the cylinder of the differential transformer. A relative movement amount between the provided cylindrical core is detected. That is, the voltage fluctuation generated by the relative movement is detected, and the displacement amount between the other end portions of the pair of feelers, that is, the outer diameter displacement amount of the workpiece is detected.

Japanese Patent No. 3163784

  However, in the dimension measuring apparatus shown in Patent Document 1, the operating transformer and the core are formed in a cylindrical shape and a columnar shape. For this reason, when the operating transformer and the core move in an arc shape according to a change in the outer diameter of the workpiece, for example, the relative positional relationship such as a gap between the two changes momentarily according to the arc-shaped movement. As a result, there is a possibility that the amount of movement of the core that actually moves in an arc shape cannot be accurately detected.

  This invention is made | formed in view of such a situation, and it aims at providing the dimension measuring apparatus which can detect the outer diameter of the workpiece processed with a machine tool accurately.

  (Claim 1) The dimension measuring apparatus of the present invention is supported by a main body having a first fulcrum and a second fulcrum, and swingable on the first fulcrum, and abuts on the outer peripheral surface of the workpiece on one end side, A first feeler that swings in accordance with a displacement of the outer diameter of the workpiece, and is swingably supported by the second fulcrum, abutting the outer peripheral surface of the workpiece on one end side, and the outer diameter of the workpiece A second feeler that oscillates according to the displacement of the main body and the first feeler on a side opposite to the one end side with respect to the first fulcrum, relative to the main body and the first feeler. A first detector having an arc-shaped detection trajectory centered on the first fulcrum, and a position opposite to the one end side with respect to the second fulcrum; When the relative position between the main body and the second feeler is detected In, and a second detector having a detection trajectory of an arc about said second fulcrum.

  Thus, the first and second detectors have arc-shaped detection trajectories corresponding to the arc-shaped movement trajectories of the first and second feelers around the first and second fulcrums, respectively. As a result, when the workpiece is machined and the outer diameter changes in the workpiece, the first and second detectors move in the arc shape around the first and second fulcrums, respectively. Since the displacement of the end portion opposite to the one end side can be detected with high accuracy, the outer diameter of the workpiece can be obtained with high accuracy.

  (Claim 2) The first detector includes a first feeler portion fixed to the first feeler side and a first main body portion fixed to the main body portion side, and the second detector. Comprises a second feeler part fixed to the first feeler side and a second body part fixed to the main body part side, and the dimension measuring device comprises the first feeler part and the first main body part. Between the first one member which is one of the first member and the first counterpart member to which the first one member is fixed, and is formed of a material having a coefficient of thermal expansion different from that of the main body, depending on the temperature. A first spacer that changes a relative position between the first one member and the first counterpart member, a second one member that is one of the second feeler portion and the second main body portion, and the second first member. Coefficient of thermal expansion different from that of the main body between the second mating member to which the side member is secured It made of a material, and a second spacer for varying the relative position of the second mating member and the second contrast member according to temperature, may be provided.

  Therefore, when the workpiece is machined, temperature changes occur in the workpiece and the main body, and the first and second spacers are displaced when the dimensions of the workpiece and the main body are thermally displaced according to the respective thermal expansion coefficients. Similarly, due to the temperature change, the first one member (second one member) is displaced with respect to the first mating member (second mating member) by thermal displacement corresponding to each thermal expansion coefficient. At this time, the direction of displacement of the first one member (second one member) is substantially opposite to the direction of thermal displacement of the workpiece and the main body. For this reason, the thermal displacement of the workpiece and the main body can be canceled by the thermal displacement of the first spacer and the second spacer, that is, the displacement of the first one member (second one member). Thereby, even if temperature environment changes, the outer diameter of a workpiece can be detected accurately. When the first feeler portion (second feeler portion) is the first one member (second one member), the first mating member (second mating member) is the first feeler (second feeler). When the first main body (second main body) is the first one member (second one member), the first mating member (second mating member) is the main body.

  (Claim 3) In addition, the direction of change in the relative position of the first one member and the first mating member according to the temperature by the first spacer is the facing direction of the first and second feelers. The change direction of the relative position between the second one member and the second mating member according to the temperature by the second spacer may be the first feeler and the second feeler. The direction may be inclined with respect to the direction facing the feeler.

  For this reason, when the temperature environment changes, the direction of thermal displacement of the first spacer and the second spacer is inclined in the direction in which the arc-shaped detection tracks of the first and second detectors are established, thereby The outer diameter of an object can be accurately detected.

  (Claim 4) Further, the first detector includes a first excitation wiring provided on one of the main body and the first feeler for exciting an amplitude modulation voltage, and a first provided on the other for generating an output voltage. The second detector is provided on one of the main body and the second feeler for exciting an amplitude modulation voltage, and the second detector is provided on the other for generating an output voltage. Output wiring.

  As a result, the first and second output wirings output high-precision absolute position signals of the first and second feelers for the main body, respectively, so that the outer diameter of the workpiece can be detected with high accuracy and the relative position. Various arithmetic processes for obtaining the value can be reduced.

It is a schematic plan view of the grinding device to which the dimension measuring device concerning this embodiment was applied. FIG. 2 is a cross-sectional view taken along arrow 2-2 in FIG. 1, schematically showing a configuration of a dimension measuring device. FIG. 3 is an enlarged view of a first detector portion of FIG. 2. It is an enlarged view of the 1st feeler part and 1st main-body part of a 1st detector. It is an enlarged view of the 2nd feeler part and 2nd main-body part of a 2nd detector. FIG. 6 is a cross-sectional view taken along arrow 6-6 in FIG. 4. It is a figure which shows an example of the amplitude modulation voltage input into the 1st excitation wiring of a modulation wave resolver. It is a figure explaining the shape of the 1st spacer which concerns on another embodiment.

(Configuration of grinding equipment)
First, a grinding apparatus applied to an embodiment of the present invention will be described. As shown in FIG. 1, the grinding apparatus includes a base 10, a servo motor 11, a table 12, a main shaft 13, a main shaft base 14, a main shaft servo motor 15, a tailstock 16, and a grindstone base 19. The wheel head servo motor 21, the wheel shaft 29, the wheel G, the motor M, and the dimension measuring device 40 are provided.

  A table 12 is provided on the base 10 so as to be slidable in the Z-axis direction parallel to the spindle axis. The table 12 is driven in the Z-axis direction by the servo motor 11. Further, on the table 12, a headstock 14 for rotatably supporting the main shaft 13 is disposed. The main shaft 13 is rotated by a main shaft servomotor 15. In FIG. 1, a tailstock 16 is disposed on the right side of the table 12. A cylindrical workpiece W (hereinafter, referred to as only the workpiece W) is held between the center 16a of the tailstock 16 and the center 13a of the main shaft 13.

  On the rear side of the base 10 (upper side in FIG. 1), a grindstone base 19 that can move forward and backward relative to the workpiece W is disposed. The wheel head 19 can be moved forward and backward in the X-axis direction perpendicular to the Z-axis by forward and reverse rotation of the wheel head servo motor 21. A grindstone shaft 29 that is rotationally driven by a motor M is rotatably supported on the grindstone base 19. Then, the grinding wheel G is fixed to the grinding wheel shaft 29. A dimension measuring device 40 that measures the outer diameter of the workpiece W ground by the grinding wheel G is installed on the table 12. The servo motor 11, the spindle servo motor 15, the servo motor 21, and the dimension measuring device 40 are each controlled by a control device (not shown).

(Dimension measuring device 40)
As shown in FIG. 2, the dimension measuring device 40 includes a main body 42, a first feeler 44, a second feeler 45, a first detector 46, a second detector 47, and a first feeler spacer 72. , A first main body spacer 78, a second feeler spacer 74, a second main body spacer 80, and an output signal processing device (not shown). The first detector 46 and the second detector 47 are known modulation wave resolver detectors.

  The main body 42 is made of an iron-based material such as stainless steel. The main body 42 is formed in a substantially rectangular parallelepiped shape. As shown in FIG. 2, the main body 42 is formed with recesses 42a and 42b having an opening on the right side of FIG. 2 and extending in the X-axis direction. The recesses 42a and 42b are formed apart in the vertical direction (vertical direction in FIG. 2). Moreover, the main-body part 42 has the recessed parts 42d and 42e which have an opening part in the up-down direction of FIG. 2 of each recessed part 42a, 42b in the opposite opening part side among recessed parts 42a, 42b.

  The main body 42 has a first fulcrum 52 extending in the front-rear direction of FIG. 2 on the opening side of the recess 42a. Furthermore, the main body portion 42 has a second fulcrum 54 extending in the front-rear direction of the drawing in FIG. The first and second fulcrums 52 and 54 are each formed by a cylindrical pin, and are press-fitted into holes provided in the recess 42a and the recess 42b.

  The first feeler 44 and the second feeler 45 are each a long member. The first feeler 44 and the second feeler 45 face each other so as to be symmetrical with respect to the center plane CL of the main body portion 42, and a part of each is accommodated in each of the recesses 42a and 42b. The center plane CL is a plane that passes through the axis of the workpiece W.

  The first and second feelers 44 and 45 are swingably supported by the first and second fulcrums 52 and 54, respectively. For example, a bearing is interposed between the through holes 44 b and 45 b formed in the first and second feelers 44 and 45 and the first and second fulcrums 52 and 54. The first and second feelers 44 and 45 have contacts 44a and 45a on one end side (right side in FIG. 2).

  Each tip of the contacts 44a and 45a can come into contact with the outer periphery of the workpiece W from both sides. At this time, a contact line is formed so that a virtual line Li connecting the contact points of the respective tip portions contacting the workpiece W passes through a substantially center of a circle formed on the outer periphery of a cross section orthogonal to the axial direction of the workpiece W. 44a and 45a are arranged. As a result, the distance between the contact points of the tip portions of the contacts 44a and 45a is equal to the diameter of the cylindrical outer peripheral surface of the workpiece W. As a result, the first and second feelers 44 and 45 swing around the first and second fulcrums 52 and 54 according to the displacement of the outer diameter of the workpiece W.

  The first and second detectors are provided on one end side of the first and second feelers 44 and 45 provided with the contacts 44a and 45a and on the other end side opposite to the first and second fulcrums 52 and 54, respectively. 46 and 47 are provided, respectively. The first and second detectors 46 and 47 detect the relative positions between the main body 42 and the first and second feelers 44 and 45, and are circles around the first and second fulcrums 52 and 54. It has an arc-shaped detection trajectory. The arc-shaped detection trajectory will be described later. Since the first and second detectors 46 and 47 have the same configuration, the first detector 46 will be described below.

  As shown in FIGS. 2 to 6, the first detector 46 includes a first feeler portion 62 (corresponding to a first one member) and a first main body portion 66. The first feeler portion 62 includes a plate-like first feeler substrate 62a that is rectangular in plan view. The first feeler substrate 62a is formed of, for example, ceramic that is an insulating material having a smaller thermal expansion coefficient than the main body 42 and the workpiece W. However, the first feeler substrate 62a is not limited to ceramics, and may be any insulating material having a smaller thermal expansion coefficient than the main body 42 and the workpiece W. On the first feeler substrate 62a of the first feeler portion 62, a first excitation wiring 62b (see FIG. 4), which will be described later, forming an arc-shaped detection track of the present invention is printed in an arc shape. As will be described in detail later, the first excitation wiring 62b excites an amplitude modulation voltage (see FIG. 7).

(First feeler spacer 72)
As shown in FIGS. 2 and 3, the first feeler substrate 62 a has a plane parallel to the swing direction of the first feeler 44 with the first fulcrum 52 as the center. The first filler spacer 72 (corresponding to the first spacer) having a rectangular parallelepiped shape is fixed to the side surface on the other end side of the corresponding member. The first feeler spacer 72 is made of aluminum having a large thermal expansion coefficient, for example.

  The first feeler spacer 72 is a rectangular parallelepiped, and is interposed between the first feeler substrate 62a of the first feeler portion 62 and the first feeler 44 (first mating member). Specifically, in the first feeler spacer 72, one surface of the rectangular parallelepiped is fixed to the side surface of the first feeler 44, which is an attachment surface of the first feeler spacer 72 (see FIGS. 2 and 3). In the first feeler spacer 72, the first feeler substrate 62 a is fixed to the back surface of the rectangular parallelepiped surface fixed to the side surface of the first feeler 44. The first feeler spacer 72 is formed of a material having a coefficient of thermal expansion different from that of the main body 42, and thermally expands or contracts depending on the temperature. Thereby, the relative position of the 1st feeler part 62 and the 1st feeler 44 is separated or approached in the direction orthogonal to the side surface of the 1st feeler 44, ie, the up-down direction in FIG. 2, FIG.

  Note that the material of the first feeler spacer 72 is not limited to aluminum, but may be a material having a predetermined thermal expansion coefficient. Here, the predetermined coefficient of thermal expansion refers to a coefficient of thermal expansion that can offset the thermal displacement correspondingly when the workpiece W and the main body 42 are actually thermally expanded (or thermally contracted). . Specifically, the first feeler substrate 62a is displaced in a direction substantially opposite to the displacement direction of the workpiece W and the main body 42 due to the thermal displacement of the first feeler spacer 72, so that the workpiece W and the main body 42 are displaced. The thermal expansion coefficient that can offset the displacement. The predetermined thermal expansion coefficient may be obtained in advance by experiments or the like.

  As shown in FIGS. 2-4, the 1st main-body part 66 is provided with the 1st main-body-part board | substrate 66a of the plate-shaped member which planar view is a rectangle. The first main body substrate 66a is formed of ceramics, for example, similarly to the first feeler substrate 62a. However, the first main body portion substrate 66a is not limited to ceramics like the first feeler substrate 62a, and may be any insulating material as long as the thermal expansion coefficient is smaller than that of the main body portion 42 and the workpiece W. . On the first body substrate 66a of the first body portion 66, a first output wiring 66b, which will be described later, forming an arc-shaped detection track of the present invention is printed in an arc shape. The first output wiring 66b generates an output voltage.

(First body part spacer 78)
As shown in FIGS. 2 and 3, the first main body portion substrate 66 a of the first main body portion 66 is fixed to the adapter 76, and the adapter 76 is disposed on the side surface of the recess 42 d of the main body portion 42 via the first main body portion spacer 78. It is fixed on 42d1. As shown in FIG. 3, the adapter 76 has a cylindrical cylindrical main body portion 76a and a flange portion 76b formed on the lower outer periphery of the cylindrical main body portion 76a in FIG. The first body portion substrate 66a is fixed in the cylinder of the cylindrical body portion 76a so that the plane thereof is parallel to the swinging direction of the first feeler 44 around the first fulcrum 52 (see FIG. 1). The first main body substrate 66a is opposed to the first output wiring 66b printed on the plane and the first excitation wiring 62b of the first feeler substrate 62a with a predetermined gap d. (See FIG. 6). That is, the first feeler substrate 62a is inserted into the cylinder of the cylindrical main body 76a and can swing around the first fulcrum 52.

  The first main body spacer 78 is formed of a material having a thermal expansion coefficient different from that of the main body 42. Specifically, the first main body spacer 78 is formed of an amber material (or an invar material) that is smaller than the thermal expansion coefficient of the main body 42. As shown in FIGS. 2 and 3, the first main body spacer 78 is formed in a cylindrical shape, and is arranged so that the cylindrical axis coincides with the cylindrical axis of the cylindrical main body 76 a of the adapter 76. Then, with the adapter 76 and the first main body spacer 78 arranged as shown in FIGS. 2 and 3, the two bolts 92 are arranged in the cylindrical axis direction of the flange 76 b of the adapter 76 and the first main body spacer 78. Inserted and fixed to the side surface 42d1 of the recess 42d of the main body 42 by screwing.

  As a result, when the same temperature change occurs in the main body 42 and the first main body spacer 78, the entire portion occupied by the first main body spacer 78 is compared with the case where the same material as the main body 42 is replaced. Thus, the amount of displacement of the adapter 76 in the vertical direction in FIG. 2 can be suppressed. The first main body spacer 78 is not limited to an amber material (or an invar material). The first main body spacer 78 has a coefficient of thermal expansion smaller than the coefficient of thermal expansion of the main body 42, and the amount of displacement of the main body 42 in the vertical direction in FIG. Any member may be used as long as the amount of displacement in the vertical direction can be suppressed.

(Modulated wave resolver)
Here, a known modulated wave resolver will be briefly described. The modulation wave resolver applies a high-frequency modulation wave (amplitude modulation voltage) having different amplitudes as shown in FIG. 7, and excites the excitation side coil (first excitation wiring 62b in this embodiment). Note that the waveform in FIG. 7 is merely an example. In such a state, a digital signal indicating an absolute position is output from the opposing output coil (first output wiring 66b in this embodiment). At this time, the absolute position refers to the coil position on the output side with respect to the coil position on the excitation side. When the relative position of the excitation side coil and the output side coil arranged to face the excitation side coil is displaced (in this embodiment, rotational displacement about the first fulcrum 52), the displacement corresponds to the displacement. The output side coil outputs an absolute digital signal. At this time, the output digital signal indicates the absolute position after the relative position is displaced.

(Shapes of the first excitation wiring 62b and the first output wiring 66b)
Next, the shapes of the first excitation wiring 62b and the first output wiring 66b constituting the detection unit of the modulated wave resolver according to the present invention will be described. In the present embodiment, the first excitation wiring 62b, which is a coil on the excitation side, is connected to a modulation wave output machine (not shown). The first output wiring 66b is connected to an unillustrated output signal processing device.

  As shown in FIG. 4, the first excitation wiring 62b (two-dot chain line) is printed on the first feeler substrate 62a provided on the first feeler 44 corresponding to one side so that the rectangular wave pattern has an arc shape. The Specifically, the first excitation wiring 62b is printed around a virtual arc Ra having a radius R1 drawn around the axis O of the first fulcrum 52. That is, in the first excitation wiring 62b, the straight line Lh, which is a part of the rectangular wave pattern extending to the outer diameter side and the inner diameter side of the virtual arc Ra, extends substantially uniformly on both sides of the virtual arc Ra. Printed on the first feeler substrate 62a. The plurality of straight lines Lh forming the rectangular wave pattern are provided so as to coincide with straight lines drawn radially from the axis O of the first fulcrum 52 in the radial direction of the virtual arc Ra. Then, the end points of each straight line Lh are alternately connected on both the outer diameter side and the inner diameter side of the virtual arc Ra to form the first excitation wiring 62b.

  As shown in FIG. 4, the first output wiring 66b facing the first excitation wiring 62b also has a rectangular wave shape on the first body portion substrate 66a of the first body portion 66 provided in the body portion 42 corresponding to the other. The pattern is printed in an arc shape. Specifically, the first output wiring 66b is also printed by the same method and shape as the first excitation wiring 62b drawn around the axis O of the first fulcrum 52. That is, the first output wiring 66b is printed around a virtual arc Rb (= virtual arc Ra) drawn around the first fulcrum 52 having the same curvature as the virtual arc Ra of the first excitation wiring 62b.

  That is, in the first output wiring 66b, the straight line Lh, which is a part of the rectangular wave pattern extending to the outer diameter side and the inner diameter side of the virtual arc Rb, extends substantially equally on both sides of the virtual arc Rb. Printed on the first main body substrate 66a. The plurality of straight lines Lh forming the rectangular wave pattern are provided so as to coincide with a straight line drawn radially from the axis O of the first fulcrum 52 in the radial direction of the virtual arc Rb. Then, the end points of each straight line Lh are alternately connected on both the outer diameter side and the inner diameter side of the virtual arc Rb to form the first output wiring 66b.

  The first excitation wiring 62b and the first output wiring 66b are arranged so that the virtual arc Ra and the virtual arc Rb overlap when viewed from the axial direction of the workpiece W in a state before the grinding apparatus is operated. (See FIG. 4).

  In the above description, the first detector 46 has been described in detail. However, the second detector 47 has the same configuration as the first detector 46. Thereby, about the 2nd detector 47, in said description, the 1st feeler 44 which the 1st detector 46 has, the 1st feeler part 62, the 1st feeler board | substrate 62a, the 1st excitation wiring 62b, the 1st main body part 66, the first output wiring 66b, the first feeler spacer 72, and the first main body spacer 78 are respectively connected to the second feeler 45, the second feeler portion 64, the second feeler substrate 64a, the second excitation wiring 64b, and the second main body portion. 68, the second output wiring 68b, the second feeler spacer 74, and the second main body spacer 80. In addition, the same code | symbol is attached | subjected about the site | part which was not demonstrated (for example, virtual circular arc Ra, Rb etc.).

(Function)
Next, the operation of the first detector 46 and the second detector 47 will be described. First, the description will be made on the assumption that the grinding apparatus has no temperature change. In the state shown in FIG. 1, it is assumed that the grinding device is operated and a control device (not shown) cuts and advances the grinding wheel G with respect to the workpiece W. Thereby, the outer diameter of the cylindrical outer peripheral surface of the workpiece W is reduced. In such a state, the outer diameter of the cylindrical outer peripheral surface of the workpiece W is measured by the dimension measuring device 40. In the dimension measuring device 40, the first feeler 44 and the second feeler 45 are swung around the first and second fulcrum points 52 and 54 with respect to the state before the workpiece W is processed. The swinging direction is a direction in which the contacts 44a and 45a approach each other on the workpiece W side which is one end side. Further, on the other end side where the first detector 46 and the second detector 47 are provided, the other end portions of the first feeler 44 and the second feeler 45 are in directions away from the main body portion 42.

  At this time, in the first detector 46 (second detector 47), the first excitation wiring 62b (the second feeler substrate 64a) of the first feeler substrate 62a (second feeler substrate 64a) fixed to the first feeler 44 (second feeler 45). The second excitation wiring 64b) is rotated on the virtual arc Ra around the first fulcrum 52 (second fulcrum 54). At this time, the first output wiring 66b (second output wiring 68b) facing the first excitation wiring 62b (second excitation wiring 64b) has a first fulcrum 52 (second fulcrum 54) that coincides with the virtual arc Ra. It is formed on a virtual arc Rb with the center.

  Therefore, even if the first excitation wiring 62b (second excitation wiring 64b) is rotationally displaced about the first fulcrum 52 (second fulcrum 54), each of the first excitation wiring 62b (second excitation wiring 64b) The straight line Lh and each straight line Lh of the first output wiring 66b (second output wiring 68b) can always maintain a stable relative positional relationship. For this reason, the first detector 46 (second detector 47), which is a detector of the modulated wave resolver, can detect the displacement amount (= displacement angle) of the first feeler 44 with high accuracy. Thereby, when the dimension measuring apparatus 40 is applied as a sizing apparatus, the first detector 46 (second detector 47) can output the dimension (output signal) set and stored in advance with high accuracy.

  Next, the temperature of the workpiece W and the main body 42 is increased (changed) by the processing heat when the grinding wheel G grinds the workpiece W during the machining of the workpiece W and the supply of cutting lubricant to the entire grinding device. ) Will be described. In this way, when the temperature of the entire grinding apparatus rises, the workpiece W and the main body 42 expand by an amount corresponding to the thermal expansion coefficient of each. When the workpiece W is thermally expanded, the outer diameter of the workpiece W is increased. For this reason, the first feeler 44 (second feeler 45) is displaced (opened) in a direction away from the opposing second feeler 45 (first feeler 44) on the workpiece W side.

  The first feeler 44 (second feeler 45) swings around the first fulcrum 52 (second fulcrum 54). For this reason, on the first detector 46 (second detector 47) side, the first feeler 44 (second feeler 45) and the main body portion 42 are displaced (closed) in the approaching direction. For this reason, in the first detector 46 (second detector 47), the first excitation wiring 62b (first feeler substrate 62a (second feeler substrate 64a) of the first feeler substrate 62a (second feeler substrate 64a) is only increased due to the temperature rise regardless of the processing of the workpiece W. The relative position between the second excitation wiring 64b) and the first output wiring 66b (second output wiring 68b) of the first main body substrate 66a (second main body substrate 68a) fixed to the main body 42 varies. As a result, the first output wiring 66b (second output wiring 68b) may output the same digital signal as when the outer diameter of the workpiece W increases.

  Similarly to the workpiece W, the main body 42 also thermally expands in the direction of the arrow Ar1 shown in FIG. For this reason, the position of the first fulcrum 52 (second fulcrum 54) and the position of the first output wiring 66b (second output wiring 68b) vary. This also changes the relative position between the first excitation wiring 62b (second excitation wiring 64b) and the first output wiring 66b (second output wiring 68b), and the first output wiring 66b (second output wiring 68b). From this, there is a possibility that the same digital signal as that when the outer diameter of the workpiece W changes is output.

  However, the dimension measuring apparatus 40 includes a first feeler spacer 72 (second feeler spacer 74) between the first feeler substrate 62a (second feeler substrate 64a) and the first feeler 44 (second feeler 45). . For this reason, when the temperature rises, the first feeler spacer 72 (second feeler spacer 74) expands by an amount corresponding to the thermal expansion coefficient provided by itself. And with respect to the 1st feeler 44 (2nd feeler 45), the 1st feeler board | substrate 62a (2nd feeler board | substrate 64a) is the 1st feeler spacer by the expansion amount of the 1st feeler spacer 72 (2nd feeler spacer 74). 72 (second feeler spacer 74) is displaced in the expansion direction.

  For this reason, the relative position of the first feeler substrate 62a (second feeler substrate 64a) and the first output wiring 66b (second output wiring 68b) changes, and approaches the state before the temperature rises. As a result, the first output wiring 66b (second output wiring 68b) of the first detector 46 (second detector 47) outputs the same digital signal as when the outer diameter of the workpiece W changes when the temperature rises. Can be suppressed. In the above description, the material (ie, thermal expansion coefficient), shape, size, and the like of the first feeler spacer 72 (second feeler spacer 74) may be determined in consideration of the amount of thermal expansion of each part of the actual machine tool. Good.

  In addition, the dimension measuring apparatus 40 includes a first body part spacer having a thermal expansion coefficient smaller than that of the main body part 42 between the first main body part substrate 66a (second main body part substrate 68a) and the main body part 42. 78 (second main body spacer 80). Thereby, the first main body spacer 78 (second main body spacer 80) suppresses the amount of thermal expansion of the main body 42 when the temperature rises. For this reason, the main body portion 42 is largely thermally expanded, and the displacement of the relative position between the first feeler substrate 62a (second feeler substrate 64a) and the first output wiring 66b (second output wiring 68b) is suppressed. . Thereby, the relative position of the 1st feeler board | substrate 62a (2nd feeler board | substrate 64a) and the 1st output wiring 66b (2nd output wiring 68b) can be maintained in the state near the state before temperature rise. Therefore, the first output wiring 66b (second output wiring 68b) of the first detector 46 (second detector 47) outputs the same digital signal as when the outer diameter of the workpiece W changes when the temperature rises. Can be suppressed.

(effect)
As is clear from the above description, according to the above embodiment, the first detector 46 (second detector 47) has the first feeler 44 (second fulcrum 54) centered on the first fulcrum 52 (second fulcrum 54). Each of the two feelers 45) has an arc-shaped detection track corresponding to the arc-shaped movement track. Thereby, when the workpiece W is machined and an outer diameter change occurs in the workpiece W, the first detector 46 (second detector 47) is circular with the first fulcrum 52 (second fulcrum 54) as the center. Since the displacement of the other end of the first feeler 44 (second feeler 45) moving in an arc shape can be detected with high accuracy, the outer diameter of the workpiece W can be obtained with high accuracy.

  Moreover, according to the said embodiment, the 1st feeler spacer 72 (2nd feeler spacer) which is formed with the material which has a thermal expansion coefficient different from the main-body part 42, and receives the influence of the heat similar to the workpiece W and the main-body part 42. 74). Thereby, the first feeler substrate 62a (second feeler substrate 64a) is displaced by the thermal expansion of the first feeler spacer 72 (second feeler spacer 74), and the first feeler substrate 62a (second feeler substrate) at the time of thermal displacement. A large displacement of the relative position between the substrate 64a) and the first output wiring 66b (second output wiring 68b) is suppressed. Thereby, even if a temperature environment changes, the outer diameter of the workpiece W can be detected accurately.

  Moreover, according to the said embodiment, the modulated wave resolver was applied to the 1st detector 46 (2nd detector 47). Thereby, since the highly accurate absolute position signal of the 1st feeler 44 (2nd feeler 45) with respect to the main-body part 42 is output from the 1st output wiring 66b (2nd output wiring 68b), respectively, the 1st feeler 44 is output. Various calculation processes for obtaining the relative position of the (second feeler 45) can be reduced, and the cost can be reduced.

  In the above embodiment, a modulated wave resolver is applied as the first detector 46 (second detector 47), but the present invention is not limited to this mode. As another aspect, the first detector (second detector) may be a normal resolver constituted by a coil and a core described in the related art. The first detector (second detector) may be an MR sensor, a Hall sensor, an optical encoder, or the like. In these cases, similarly to the above embodiment, it is only necessary that the opposing detection portions have arc-shaped detection trajectories.

  Moreover, in the said embodiment, although the modulation wave resolver which outputs a digital signal was applied as the 1st detector 46 (2nd detector 47), it is not restricted to this aspect. As another aspect, the first detector (second detector) may be of a type that outputs a linear analog signal.

  Moreover, in the said embodiment, although the 1st feeler spacer 72 (2nd feeler spacer 74) fixed to the 1st feeler 44 (2nd feeler 45) was made into the 1st spacer (2nd spacer), it is not restricted to this. Alternatively, the first main body spacer 78 (second main body spacer 80) fixed to the main body 42 may be used as the first spacer (second spacer).

  Moreover, in the said embodiment, the 1st feeler spacer 72 (2nd feeler spacer 74) and the 1st main-body part spacer 78 (2nd main-body part spacer 80) were provided simultaneously. However, the present embodiment is not limited to this, and only one of the spacers may be provided. This also provides a reasonable effect.

  In the above embodiment, the first feeler spacer 72 (second feeler spacer 74) and the first main body spacer 78 (second main body spacer 80) are made of metal. However, the present invention is not limited to this mode, and each spacer is not limited to metal, and may be resin, for example.

  Moreover, in the said embodiment, the 1st feeler spacer 72 (2nd feeler spacer 74) was made into the rectangular parallelepiped shape expanded in the direction orthogonal to each attachment surface. However, the shape is not limited to such a shape, and the first feeler spacer may have a tapered surface 94a as shown in FIG. Thereby, when temperature change (for example, temperature rise) arises, the 1st feeler 44 (2nd feeler 45) which is the 1st partner member (second partner member), and the 1st one member (second 1 The direction of change in the relative position of the first feeler portion 62 (second feeler portion 64), which is the first member, with respect to the first feeler substrate 62a (second feeler substrate 64a) is the difference between the first feeler 44 and the second feeler 45. The direction is inclined with respect to the facing direction (see arrow Ar2 in FIG. 8). Note that the lengths of the two straight arrows in FIG. 8 schematically indicate the relative magnitude relationship between the displacement amounts of the first feeler spacer 94 on both the left and right sides in FIG. It is shown, and does not indicate the absolute amount of displacement.

  Specifically, the change direction of the first feeler 44 (second feeler 45) relative to the first feeler substrate 62a (second feeler substrate 64a) is the virtual arc Ra of the first excitation wiring 62b (second excitation wiring 64b). The direction is such that the virtual arc Rb of the first output wiring 66b (second output wiring 68b) overlaps. Thereby, the outer diameter of the workpiece W can be obtained with the same accuracy as when there is no temperature change as described in the above embodiment.

  Further, the relative position between the first feeler 44 (second feeler 45) and the first feeler substrate 62a (second feeler substrate 64a) in FIG. 8 indicates an initial state in which there is no temperature change.

  In the above embodiment, the dimension measuring device 40 is applied to a grinding device. However, the present invention is not limited to this aspect, and may be applied as a sizing device for other machine tools. Moreover, you may use not only a machine tool but as a measuring apparatus for measuring a dimension correctly.

DESCRIPTION OF SYMBOLS 10 ... Base, 12 ... Table, 13 ... Spindle, 14 ... Spindle base, 16 ... Tailstock, 40 ... Dimensions measuring device, 19 ... Grinding wheel stand, 42 ... Main body part 44 ... First feeler 45 ... Second feeler 46 ... First detector 47 ... Second detector 52 ... First fulcrum 54 .... Second fulcrum, 62 ... First feeler part, 62a ... First feeler board, 62b ... First excitation wiring, 64 ... Second feeler part, 64a ... Second feeler board 64b ... second excitation wiring, 66 ... first main body, 66b ... first output wiring, 68 ... second main body, 68b ... second output wiring, 72, 94 ..First feeler spacer (first spacer), 74 ... Second feeler spacer (second spacer), 78 · First body portion spacers (first spacers), 80 ... second body portion spacer (Second spacer), G ... grinding wheel, W ... workpiece.

Claims (4)

A main body having a first fulcrum and a second fulcrum;
A first feeler that is swingably supported by the first fulcrum, abuts on the outer peripheral surface of the workpiece on one end side, and swings according to the displacement of the outer diameter of the workpiece;
A second feeler that is swingably supported by the second fulcrum, abuts against the outer peripheral surface of the workpiece on one end side, and swings according to a displacement of the outer diameter of the workpiece;
Provided on the main body and the first feeler on the side opposite to the one end side with respect to the first fulcrum, detecting a relative position between the main body and the first feeler, and centering on the first fulcrum A first detector having a circular arc-shaped detection trajectory,
Provided on the main body and the second feeler on the side opposite to the one end side with respect to the second fulcrum, detecting the relative position of the main body and the second feeler, and centering on the second fulcrum A second detector having a circular arc-shaped detection trajectory,
A dimension measuring device comprising: The first detector includes a first feeler portion fixed to the first feeler side, and a first main body portion fixed to the main body portion side,
The second detector includes a second feeler part fixed to the second feeler side, and a second main body part fixed to the main body part side,
The dimension measuring device includes:
Heat different from that of the main body portion between a first one member that is one of the first feeler portion and the first main body portion and a first counterpart member that is a counterpart to which the first one member is fixed. A first spacer that is formed of a material having an expansion coefficient and changes a relative position between the first one-member and the first mating member according to a temperature;
Heat different from that of the main body portion between a second one member which is one of the second feeler portion and the second main body portion and a second counterpart member to which the second one member is fixed. A second spacer that is formed of a material having an expansion coefficient and changes a relative position between the second one-member and the second mating member according to temperature;
Comprising
The dimension measuring apparatus according to claim 1. The change direction of the relative position of the first one member and the first counterpart member according to the temperature by the first spacer is a direction inclined with respect to the opposing direction of the first feeler and the second feeler. Yes,
The change direction of the relative position of the second one-member and the second counterpart member according to the temperature by the second spacer is a direction inclined with respect to the facing direction of the first feeler and the second feeler. is there,
The dimension measuring apparatus according to claim 2. The first detector includes a first excitation wiring provided on one of the main body and the first feeler for exciting an amplitude modulation voltage, and a first output wiring provided on the other for generating an output voltage,
The second detector includes a second excitation wiring that is provided on one of the main body and the second feeler and excites an amplitude modulation voltage, and a second output wiring that is provided on the other and generates an output voltage.
The dimension measuring apparatus as described in any one of Claims 1-3.

Images