JP2007192590A - Contact-type displacement gauge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact-type displacement gauge the wear of which due to the sliding motion of a contactor is suppressed. <P>SOLUTION: An outer cylinder 220 is mounted extending downward from a through-hole 110b in a lower face portion CB of a head case 110. A rotation stop pin 340, inserted into a rotation stop pin insertion portion 322 of a shift cap 320, is fitted into a rotation stop groove 111 extending from a back portion CC to the vertical direction. A shaft 310 is inserted into the outer cylinder 220. A ball cage 230 is arranged between the outer cylinder 220 and the shaft 310. The ball cage 230 is such that a plurality of balls 231 are provided in a cylindrical member at regular spaces. The balls 231 abut against the inner peripheral face of the outer cylinder 220 and on the outer peripheral face of the shaft 310, and they are rotatably movable in the vertical direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contact displacement meter that measures the amount of displacement of an object.

  The contact-type displacement meter has a contactor (movable part) and a transformer that are in contact with the surface of an object and can be displaced in the axial direction (see, for example, Patent Document 1).

  The transformer includes a core that interlocks with the contact. When the core is displaced according to the displacement of the contact, the level of the signal output from the transformer changes in accordance with the displacement of the contact. In such a configuration, the physical displacement amount such as the height of the target object is measured by converting the physical displacement amount of the target object into an electric quantity.

A contact displacement meter generally includes a head portion including a transformer and a main body portion that controls the head portion (see, for example, Patent Document 2). An external signal is input to the main body from an external device such as a PLC (programmable logic controller). Thereby, the physical displacement amount of the object is measured at the input timing of the external signal.
Japanese Patent Laid-Open No. 2000-9412 JP 2002-131037 A

  In the contact displacement meter, for example, a rod-shaped contact is provided so as to protrude from the head portion. When the tip of the contact comes into contact with the object, the contact slides in the axial direction with respect to the head portion. As described above, the displacement of the contact is converted into an electrical signal.

  However, the contact portion of the contact with the head portion is worn by the repeated sliding operation of the contact. As a result, the sliding operation of the contact becomes unstable, and the smooth sliding operation of the contact is not performed. As a result, the measurement accuracy of the contact-type displacement meter decreases with long-term use.

  An object of the present invention is to provide a contact displacement meter in which wear due to sliding movement of a contact is suppressed.

  (1) A contact displacement meter according to the present invention is a contact displacement meter that measures a physical displacement amount of an object, and includes a casing having a hole on one surface and a cylindrical shape attached to the hole of the casing. A holding member, a rod-shaped contact provided so as to protrude from the end of the holding member through the hole and the holding member from the inside of the casing, and provided between the holding member and the contact. It comprises a rolling friction member that holds the contact slidably in the axial direction by rolling friction, and conversion means that is provided in the casing and converts the amount of movement of the contact into an electric signal.

  In the contact displacement meter according to the present invention, a cylindrical holding member is attached to a hole provided on one surface of the casing. A rod-shaped contact protrudes from the end of the holding member through the hole and the holding member from within the casing. The contact is held by a rolling friction member provided between the holding member and the contact. When the physical displacement amount of the object is measured by the contact displacement meter, the contact is brought into contact with the object and displaced relative to the casing. In this case, the contact is slid in the axial direction by rolling friction in the holding member. The amount of movement of the contact is converted into an electrical signal by conversion means provided in the casing.

  Thus, since the contact is held by the rolling friction member in the holding member, the wear of the casing due to the sliding of the contact is prevented. Further, since the contact is slid by the rolling friction member with respect to the holding member, the friction between the contact and the holding member is reduced. Thereby, wear of the contact and the holding member is suppressed.

  (2) You may further provide the movement limitation mechanism which accept | permits the axial rotation of a contactor with respect to a casing, and prevents rotation around the axial direction of a contactor.

  In this case, since friction due to rotation around the axial direction of the contact does not occur, wear of the contact and the holding member is further suppressed.

  (3) The movement limiting mechanism is provided in one of the casing and the contact along the axial direction of the contact, and on the other of the casing and the contact, and is slidably fitted in the groove. It may be constituted by a protruding part.

  In this case, when the contact is displaced, the protrusion provided on the other of the casing and the contact slides in the groove provided on one of the casing and the contact. Thereby, the sliding of the contact in the axial direction with respect to the casing is allowed, and the rotation of the contact around the axial direction is reliably prevented. Therefore, wear of the contact and the holding member is further suppressed.

  Further, since the movement limiting mechanism is realized by the casing and the groove and protrusion of the contact, the processing to the holding member that requires high accuracy is simplified. Therefore, the manufacturing cost of the holding member can be reduced.

  (4) The rolling friction member may include a plurality of spherical members rotatably provided between the holding member and the contact.

  In this case, when the contact element is displaced, each of the plurality of spherical members rotates between the holding member and the contact element, so that the contact element slides on the holding member with rolling friction. Thereby, the friction between the contact and the holding member is reduced, and wear of the contact and the holding member is suppressed.

  (5) The rolling friction member has a cylindrical body that rotatably holds a plurality of spherical members, and each of the plurality of spherical members may protrude from the inner peripheral surface and the outer peripheral surface of the cylindrical body.

  In this case, the rolling friction member is inserted into the holding portion, and the contact is inserted into the cylindrical body of the rolling friction member. Each of the plurality of spherical members protruding from the inner peripheral surface and the outer peripheral surface of the cylindrical body is in contact with the contact on the inner peripheral surface side of the cylindrical body, and is in contact with the holding member on the outer peripheral surface side of the cylindrical body.

  In this case, a spherical member can be arranged between the contact and the holding member. Therefore, the friction between the contact and the holding member is sufficiently reduced, and wear of the contact and the holding member is sufficiently suppressed.

  (6) The holding member may be press-fitted into the hole of the casing. In this case, the holding member can be attached to the casing without using a mounting bracket for the holding member. Thereby, the manufacturing cost of the holding member can be further reduced.

  According to the present invention, since the contact is held by the rolling friction member in the holding member, the wear of the casing due to the sliding of the contact is prevented. Further, since the contact is slid by the rolling friction member with respect to the holding member, the friction between the contact and the holding member is reduced. Thereby, wear of the contact and the holding member is suppressed.

  Therefore, the smooth sliding operation of the contact is ensured even during long-term use. As a result, the durability of the contact displacement meter is improved, and measurement accuracy can be maintained over a long period of time.

  Hereinafter, a contact displacement meter according to an embodiment of the present invention will be described with reference to the drawings.

(1) Configuration of Contact Displacement Meter FIG. 1 is a block diagram showing a configuration of a contact displacement meter according to the present embodiment.

  As shown in FIG. 1, a contact displacement meter 100 according to the present embodiment includes a head portion 100A and a main body portion 100B.

  The head portion 100A and the main body portion 100B are connected to each other by a cable 512. The main body 100B is connected to an external device (not shown) via a cable 81.

  The head part 100 </ b> A mainly includes a head case 110, a shaft cover part 200, a shaft part 300, and a frame part 400. The head case 110 is a substantially rectangular parallelepiped and has an opening on one side. The shaft cover portion 200 is attached to one end surface of the head case 110. The shaft portion 300 is provided to be displaceable in the head case 110 and the shaft cover portion 200. The frame unit 400 is housed in the head case 110.

  In the contact displacement meter 100, the physical displacement amount such as the height of the object is measured based on the moving distance (displacement amount) of the shaft portion 300 in the head portion 100A.

  Note that the head portion 100A of FIG. 1 is shown in a state in which an opening cover described later is removed in order to clearly show the internal configuration.

(2) Configuration of Head Unit Next, the details of the head unit 100A of the contact displacement meter 100 shown in FIG. 1 will be described with reference to FIGS.

  FIG. 2 is an exploded perspective view of the entire head unit 100A. 3 and 4 are diagrams showing details of the head case 110 of the head portion 100A. FIG. 5 is a diagram showing details of the substrate frame of the head unit 100A. 2 to 5, as indicated by arrows X, Y, and Z, three directions orthogonal to each other are defined as an X direction, a Y direction, and a Z direction.

  As described above, the head portion 100A mainly includes the head case 110, the shaft cover portion 200, the shaft portion 300, and the frame portion 400. The frame unit 400 includes a substrate frame 410 shown in FIG.

  The head case 110 has an upper surface portion CA and a lower surface portion CB parallel to the XY plane, a back surface portion CC and an opening CD parallel to the YZ plane, and a side surface portion CE and a side surface portion CF parallel to the ZX plane. The thickness of the upper surface portion CA, the rear surface portion CC, the side surface portion CE, and the side surface portion CF of the head case 110 is substantially the same, and the thickness of the lower surface portion CB is the same as that of the upper surface portion CA, the back surface portion CC, the side surface portion CE, and the side surface portion CF. Larger than thickness. As a material of the head case 110, it is preferable to use a nonmagnetic material such as zinc.

  Here, details of the head case 110 will be described. FIG. 3A is a perspective view of the head case 110 viewed from obliquely above the opening CD. FIG. 3B is a perspective view of the head case 110 viewed from obliquely above the back surface portion CC. FIG. 4 is a front view of the head case 110 viewed from the opening CD side.

  As shown in FIG. 3A, a circular through hole 110a penetrating in the Z direction is formed in a portion of the upper surface portion CA on the side surface portion CE side. In addition, a circular through hole 110b penetrating in the Z direction is formed in a portion of the lower surface portion CB on the side surface CE side. The central portion of the through hole 110a and the central portion of the through hole 110b are located on one straight line parallel to the Z direction.

  An elliptical through hole 110c extending along the X direction is formed at a portion where the upper surface portion CA and the side surface portion CF of the head case 110 intersect.

  As shown in FIG. 3B, the cable housing portion 120 is formed in a portion from the upper surface portion CA to the back surface portion CC of the head case 110.

  The cable housing portion 120 includes a cable housing groove 121 extending in the Z direction from the upper surface portion CA of the head case 110, and a connector fitting portion 122 communicating with the lower end portion of the cable housing groove 121.

  The cable housing groove 121 of the cable housing portion 120 has an inclined surface 121a and inner side surface portions 121b and 121c. The inclined surface 121a is continuously and unevenly formed on the upper surface portion CA. The inner side surface parts 121b and 121c are formed in parallel to the side surface parts CE and CF. A groove 121B extending in the Z direction is formed on the inner side surface 121b. Although not shown, a similar groove is formed on the inner side surface 121c.

  The connector fitting portion 122 of the cable housing portion 120 has a substantially rectangular parallelepiped shape. A rectangular terminal portion insertion hole 122 a penetrating in the X direction is formed on a surface parallel to the back surface portion CC of the cable housing portion 120.

  As shown in FIG. 4, a threshold portion 130 is provided on the inner back surface CC of the head case 110. The threshold portion 130 extends in the Z direction from the lower surface portion CB side of the head case 110 and is formed in a convex shape on the opening CD side.

  Further, a rotation stop groove 111 and a pin introduction groove 112 are formed in an L shape in a portion of the back surface portion CC between the threshold portion 130 and the side surface portion CE. The rotation stop groove 111 extends from the lower surface portion CB toward the upper surface portion CA. The rotation stop groove 111 is located on the same ZX plane as the straight line H connecting the center of the through hole 110a of the upper surface portion CA and the center of the through hole 110b of the lower surface portion CB. The pin introduction groove 112 extends from one end portion of the rotation stop groove 111 toward the side surface portion CF.

  Two locking portions 111 a are formed in parallel on both sides of the rotation stop groove 111. Further, a convex portion 113 is formed at the position of the back surface portion CC on the extension line of the rotation stop groove 111.

  As shown in FIGS. 3 and 4, three protrusions 114 are formed on the outer surfaces of the side part CE and the side part CF of the head case 110, respectively.

  As shown in FIG. 2, the shaft cover unit 200 includes a rubber packing 210, a cylindrical outer cylinder 220, a cylindrical ball cage 230, a rubber packing 240, a substantially cylindrical locking member 250, a ring 260, and an expandable / contractible structure. It consists of a bellows cover 270 and a ring 280.

  The upper end portion of the outer cylinder 220 is attached to the through hole 110 b of the lower surface portion CB of the head case 110 via the rubber packing 210. As will be described later, when the liquid tightness between the head case 110 and the outer cylinder 220 is sufficiently secured, the rubber packing 210 may not be attached.

  A ball cage 230 is inserted into the outer cylinder 220. Details of the ball cage 230 will be described later. A locking member 250 is fitted to the lower end portion of the outer cylinder 220 via a rubber packing 240.

  An upper end portion of the bellows cover 270 is fastened to the locking member 250 by a ring 260. The lower end portion of the bellows cover 270 is fastened to the lower end portion of the shaft 310 described later by a ring 280.

  The shaft cover portion 200 having the above configuration is provided so as to extend in the Z direction from the lower surface portion CB of the head case 110.

  The shaft portion 300 includes a rod-shaped shaft 310, a substantially cylindrical shaft cap 320, a connection pin 330, a rotation stop pin 340, an insulating cap 350, a cylindrical core 360, a rubber packing 370, a ball receiver 390, and a spherical tip member 395. Consists of.

  A shaft cap 320 is attached to the upper end portion of the shaft 310. The shaft cap 320 includes a cylindrical shaft connection portion 321, a rotation stop pin insertion portion 322, and a cylindrical core connection portion 323. When attaching the shaft cap 320 to the shaft 310, the shaft connecting portion 321 is fitted to the upper end portion of the shaft 310.

  A through hole 311 penetrating in one direction on the XY plane is formed at the upper end of the shaft 310. A through hole 321a that penetrates in one direction on the XY plane is formed in the shaft connection portion 321 of the shaft cap 320. The connection pin 330 is inserted into the through hole 311 of the shaft 310 and the through hole 321 a of the shaft cap 320 in a state where the shaft connection part 321 of the shaft cap 320 is fitted to the upper end of the shaft 310. Thereby, the shaft cap 320 is fixed to the shaft 310.

  A pin hole 322 a is provided in the rotation stop pin insertion portion 322 of the shaft cap 320. A rotation stop pin 340 is inserted into the pin hole 322a. One end of the rotation stop pin 340 protrudes from the outer peripheral surface of the shaft cap 320. A cylindrical core 360 is inserted into the core connecting portion 323 of the shaft cap 320 via an insulating cap 350. As will be described later, the core 360 is attached to the head case 110 at the same time as the frame portion 400 during actual assembly.

  Further, a screw hole is formed in the lower end portion of the shaft 310, and the ball receiver 390 is inserted into the screw hole. A tip member 395 is attached to the ball receiver 390.

  The shaft portion 300 having the above-described configuration is inserted into the head case 110 and the shaft cover portion 200 from the through hole 110a of the upper surface portion CA of the head case 110 so as to be slidable in the Z direction.

  In the actual assembly, the rotation stopper pin 340 is attached to the shaft cap 320 after the shaft portion 300 is inserted into the head case 110. And the shaft part 300 is rotated centering on an axial center. At this time, one end of the rotation stop pin 340 protruding from the outer peripheral surface of the shaft cap 320 is fitted into the pin introduction groove 112 (FIG. 4) of the back surface portion CC of the head case 110. Further, the shaft portion 300 is moved along the Z direction in a state where the rotation stop pin 340 is perpendicular to the back surface portion CC of the head case 110. Thereby, one end of the rotation stop pin 340 is fitted in the rotation stop groove 111 (FIG. 4).

  Further, after the shaft 310 is inserted into the head case 110 and the shaft cover portion 200, the ball receiver 390 and the tip member 395 are attached.

  With the shaft portion 300 inserted into the head case 110 and the shaft cover portion 200, the sealing member 380 is attached to the through hole 110 a of the head case 110 via the rubber packing 370.

  The frame unit 400 includes a board frame 410, a circuit board 420, a cylindrical bobbin 430, a cylindrical magnetic shield 440, a spring 450, and a rod-shaped thermistor 460. The frame part 400 is attached into the head case 110 from the opening CD of the head case 110.

  Here, details of the substrate frame 410 will be described.

  FIG. 5A is an enlarged perspective view of the substrate frame 410 shown in FIG. 2, and FIG. 5B is a perspective view showing the back surface of the substrate frame 410 of FIG.

  As shown in FIGS. 5A and 5B, the substrate frame 410 includes a substantially rectangular parallelepiped shaft frame 411 extending in the Z direction and a substrate mounting plate 412 substantially parallel to the YZ plane.

  When the substrate frame 410 is mounted in the head case 110, the shaft frame 411 is disposed in a region closer to the side surface CE than the threshold portion 130 (FIG. 4) of the head case 110, and the substrate mounting plate 412 is the threshold. It is arranged in a region closer to the side surface portion CF than the portion 130.

  The shaft frame 411 of the substrate frame 410 shown in FIG. 5 has a hollow structure. A through hole 411a communicating with the inside is formed in the upper end surface 411A of the shaft frame 411. Further, the lower portion of the shaft frame 411 is open.

  On the side surface 411B and the side surface 411C parallel to the YZ plane of the shaft frame 411, cuts 411b and 411c extending along the Z direction from the lower end are formed. The lower portions of the cuts 411b and 411c are enlarged in the Y direction.

  As shown in FIG. 5A, a notch 411e is formed in the portion of the side surface 411B near the upper end surface 411A. Moreover, as shown in FIG.5 (b), the through-hole 411d is formed in the part of side surface 411C of upper end surface 411A vicinity.

  The board mounting plate 412 of the board frame 410 is curved in a concavo-convex shape so as to follow the shape of the cable housing part 120 of the head case 110 of FIG. In addition, a rectangular through hole 412 a is formed in a predetermined portion of the substrate mounting plate 412.

  Protrusions 412b, 412c, and 412d are formed in parallel on the side of the substrate mounting plate 412 so as to protrude in the X direction. Note that the tip of the protrusion 412c is bent inward.

  As shown in FIG. 2, a bobbin 430, a magnetic shield 440 and a spring 450 are inserted into the shaft frame 411 of the substrate frame 410. The magnetic shield 440 is made of permalloy, for example. In the shaft frame 411, the bobbin 430 is disposed in the magnetic shield 440. The length of the magnetic shield 440 and the length of the bobbin 430 in the Z direction are equal. A spring 450 is disposed so as to surround the outer peripheral surface of the magnetic shield 440.

  A primary winding and a secondary winding are wound around the outer peripheral surface of the bobbin 430. The bobbin 430, the primary winding, and the secondary winding constitute a transformer.

  Actually, the core 360 of the shaft portion 300 is inserted into the bobbin 430 when the frame portion 400 is mounted in the head case 110. At this point, the core 360 is not attached to the shaft cap 320. Then, after the frame part 400 is mounted in the head case 110, the core 360 is inserted into the shaft cap 320 through the insulating cap 350.

  A circuit board 420 having a plurality of wirings and holes is attached to the board mounting plate 412 of the board frame 410. At that time, the projecting piece 421 provided on one side of the circuit board 420 is fitted into the notch 411e of the shaft frame 411 in FIG. 5A, and on the other side of the circuit board 420 in FIG. The protrusions 412b, 412c, and 412d of the board mounting plate 412 in FIG. 5A are fitted into the three recessed portions 422 provided. Thereby, the circuit board 420 is positioned on the board mounting plate 412.

  The wiring on the circuit board 420 in FIG. 2 is connected to the primary and secondary windings of the bobbin 430 and a terminal 511a of the connector unit 511 described later. The thermistor 460 extending in the Y direction is attached to the circuit board 420.

  A cable portion 510 is attached to the cable housing portion 120 of the head case 110. The cable part 510 includes a connector part 511 on a substantially rectangular parallelepiped and a cable 512 connected to the connector part 511. A plurality of terminals 511 a protrude from one surface of the connector portion 511.

  When the cable portion 510 is attached to the cable housing portion 120, the connector portion 511 of the cable portion 510 is fitted into the connector fitting portion 122 of the cable housing portion 120 of FIG. 3B through the rubber packing 512. . At this time, the terminal 511a of the connector part 511 of FIG. 2 is inserted from the terminal part insertion hole 122a of the connector fitting part 122 of FIG. Here, the terminal portion insertion hole 122a has the same shape as the through hole 412a of the substrate frame 410, and the terminal portion insertion hole 122a of the head case 110 when the substrate frame 410 is mounted in the head case 110. And the position of the through hole 412a of the substrate frame 410 coincide with each other. Therefore, the terminal 511a of the connector part 511 protrudes to one surface side of the board frame 410 through the terminal part insertion hole 122a of the head case 110 and the through hole 412a of the board frame 410, and is connected to the wiring of the circuit board 420 on the board frame 410. Is done.

  A part of the cable 512 extending in the Z direction from the connector portion 511 is accommodated in the cable accommodation groove 121 (FIG. 3B).

  After the connector portion 511 of the cable portion 510 and a part of the cable 512 are accommodated in the cable accommodating portion 120, the groove portion 121B formed in the inner side surface portions 121b and 121c of the cable accommodating portion 120 in FIG. A cable cover 520 is attached. One surface of the cable cover 520 has a shape substantially complementary to the inclined surface 121a of the cable housing groove 121 in FIG. The connector 511 and a part of the cable 512 are securely fixed in the cable housing 120 as will be described later.

  An indicator lamp cover 522 bent in a U-shape so as to close the through hole 110c (FIG. 3B) is provided at the corner between the upper surface portion CA and the side surface portion CF of the head case 110 with a rubber packing 521. It is attached via.

  In this manner, the shaft cover portion 200, the shaft portion 300, the frame portion 400, and the cable portion 510 are attached to the head case 110.

  Next, a back cover 610 is attached to the back surface portion CC of the head case 110. The back cover 610 is curved so as to cover the corner between the back surface CC and the side surface CE of the head case 110 and the corner between the back surface CC and the side surface CF. A grip piece 611 is formed on the upper side of the back cover 610 so as to protrude in the X direction, and a grip piece 612 is formed on the lower side of the back cover 610 so as to protrude in the X direction. The distal end portion of the gripping piece 611 and the distal end portion of the gripping piece 612 are each bent inward.

  When the back cover 610 is attached to the head case 110, the tip of the grip piece 611 of the back cover 610 is hooked on the edge of the upper surface portion CA of the head case 110, and the grip piece 612 of the back cover 610 is The leading end is hooked on the edge of the lower surface portion CB of the head case 110. At this time, the grip piece 611 of the back cover 610 is in a state of covering the sealing member 380 attached to the through hole 110a of the top surface portion CA. Thereby, the sealing member 380 is prevented from falling off from the through hole 110a of the head case 110.

  A head case cover 620 is attached to the opening CD side of the head case 110 via a rubber packing 650 and a substantially rectangular inner plate 630. The head case cover 620 is curved in a U shape so as to cover the side surface CE, the side surface CF, and the opening CD of the head case 110.

  When the head case cover 620 is attached to the head case 110, the side surface CE of the head case 110 and the protrusion 114 (FIG. 3) of the side surface CF fit into the plurality of holes 621 formed in the head case cover 620. Combined. Thereby, the head case cover 620 is fixed to the head case 110.

  The back cover 610 and the head case cover 620 are made of, for example, SUS (Steinless Used Steel; stainless steel).

  In addition, although an example of the assembly method of the head unit 100A has been described here, the order of assembly is not limited thereto.

(3) Detailed Arrangement of Each Member of Head Unit Next, a detailed arrangement of each member when the assembly of the head unit 100A is completed will be described.

  6 is a cross-sectional view taken along line AA of the head portion 100A of FIG. In FIG. 6, the head portion 100A is divided into two parts with reference to the dotted line B shown in FIG. 1, and the respective parts are shown in FIGS. 6 (a) and 6 (b). FIG. 7 is a cross-sectional view of the cable housing portion 120 shown in FIGS. 2 and 3 in the ZX plane. 6 and 7, as indicated by arrows X, Y, and Z, three directions orthogonal to each other are defined as an X direction, a Y direction, and a Z direction, the direction in which the arrow is directed is a + direction, and the opposite direction is the opposite direction. -Direction.

  First, the arrangement of each member in the head case 110 and the shaft cover part 200 will be described with reference to FIG.

  As shown in FIGS. 6A and 6B, the shaft frame 411 of the substrate frame 410 is disposed in the head case 110. Further, the shaft cover portion 200 is attached so as to extend in the −Z direction from the through hole 110b of the lower surface portion CB of the head case 110. A sealing member 380 is fitted into the through hole 110a of the upper surface portion CA of the head case 110, and is held by a grip piece 611 of the back cover 610 (FIG. 2). The liquid tightness between the sealing member 380 and the head case 110 is ensured by the rubber packing 370.

  A convex portion 113 (FIG. 4) of the back surface portion CC of the head case 110 is fitted into the through hole 411 d (FIG. 5B) of the shaft frame 411. Thus, the shaft frame 411 is accurately positioned in the head case 110 with respect to the Z direction.

  A magnetic shield 440 is disposed on the shaft frame 411. The magnetic shield 440 is fixed to the shaft frame 411 by press fitting or the like.

  The bobbin 430 is fixed in the magnetic shield 440. A hemispherical protrusion 380 a is provided on the lower surface of the sealing member 380. A protrusion 380 a of the sealing member 380 is fitted to the upper end of the bobbin 430.

  A core 360 of the shaft portion 300 is slidably inserted into the bobbin 430. The core 360 is inserted and fixed to the core connecting portion 323 of the shaft cap 320 through the insulating cap 350.

  An upper end portion 411 e of the shaft frame 411 is in contact with the magnetic shield 440. Except for the upper end portion 411e of the shaft frame 411, a gap is formed between the shaft frame 411 and the magnetic shield 440, and a spring 450 is disposed in the gap. Both ends of the spring 450 are in contact with the upper end portion 411 e of the shaft frame 411 and the upper end portion of the insulating cap 350 of the shaft portion 300. Thereby, the shaft part 300 is urged downward.

  In the present embodiment, insertion of the bobbin 430 into the spring 450 saves space in the longitudinal direction in the head case 110 compared to the case where the spring 450 and the bobbin 430 are arranged in parallel in the Z direction. It has been realized. In addition, since the magnetic shield 440 is disposed between the bobbin 430 and the spring 450, the magnetic shield 440 prevents the magnetic influence from the spring 450 to the bobbin 430.

  The rotation stop pin 340 inserted into the rotation stop pin insertion portion 322 of the shaft cap 320 is fitted into the rotation stop groove 111 extending in the Z direction on the back surface portion CC through the notch 411c of the shaft frame 411. Therefore, the shaft portion 300 can slide in the Z direction, but the rotation stop pin 340 is locked by the locking portions 111a on both sides of the rotation stop groove 111. In the circumferential direction, rotation is prevented.

  Further, the inner diameter of the edge portion B1 of the through hole 110b on the one surface side of the lower surface portion CB of the head case 110 is set larger than the diameter of the shaft connection portion 321 of the shaft cap 320, and the diameter of the rotation stop pin insertion portion 322 is set. Is set smaller than. Therefore, the connection pin insertion portion 322 of the shaft cap 320 is locked to the edge portion B1 of the through hole 110b, so that the downward movement of the shaft portion 300 is limited.

  A rubber packing 210 and an outer cylinder 220 are inserted into the through hole 110b of the lower surface portion CB from below the head case 110. The outer cylinder 220 is fixed to the lower surface portion CB by press fitting or adhesive. Further, the liquid tightness between the head case 110 and the outer cylinder 220 is ensured by the rubber packing 210. The upper end of the outer cylinder 220 is press-fitted into the through-hole 110b of the lower surface part CB, and the periphery of the press-fitted portion of the outer cylinder 220 is bonded and sealed with an adhesive, whereby the head case 110 and the outer cylinder 220 are bonded. If the liquid tightness between the two is sufficiently secured, a structure in which the rubber packing 210 is not required is also possible.

  As shown in FIG. 6B, a shaft 310 is inserted into the outer cylinder 220. A ball cage 230 is disposed between the outer cylinder 220 and the shaft 310. The ball cage 230 is a cylindrical member in which a plurality of balls 231 are provided at regular intervals. The ball 231 is in contact with the inner peripheral surface of the outer cylinder 220 and the outer peripheral surface of the shaft 310 and is rotatable in the Z direction. As a result, when the shaft 310 slides in the Z direction within the outer cylinder 220, the shaft 310 is held by the ball cage 230, and the friction between the outer cylinder 220 and the shaft 310 causes the ball 231 of the ball cage 230. Rolling friction. Thereby, the friction between the outer cylinder 220 and the shaft 310 is reduced, and wear of the outer cylinder 220 is suppressed.

  Since the outer cylinder 220 is small in size and requires high accuracy in shape, the manufacturing cost is high. As described above, since the wear of the outer cylinder 220 is suppressed, the life of the expensive outer cylinder 220 is increased.

  A locking member 250 is fitted to the lower end portion of the outer cylinder 220. A rubber packing 240 is attached to the outer peripheral surface of the locking member 250. Liquid tightness between the outer cylinder 220 and the locking member 250 is ensured by the rubber packing 240.

  A bellows cover 270 is provided below the outer cylinder 220 so as to cover the periphery of the shaft 310. The upper end of the bellows cover 270 is fixed to the locking member 250 by a ring 260, and the lower end is fixed to the lower end portion of the shaft 310 by a ring 280. The bellows cover 270 expands and contracts as the shaft portion 300 moves in the Z direction.

  Next, the arrangement of the cable portion 510 (FIG. 2) in the cable housing portion 120 (FIG. 3B) will be described with reference to FIG.

  As shown in FIG. 7, the connector portion 511 of the cable portion 510 is fitted to the connector fitting portion 122 of the cable housing portion 120. The terminal 511a of the connector part 511 is connected to the wiring on the circuit board 420 (FIG. 2). A rubber packing 513 is attached to the connector portion 511. The rubber packing 513 ensures liquid tightness between the connector portion 511 and the head case 110. In addition, the cable 512 extends along a gap formed between the inclined surface 121a of the cable housing groove 121 (FIG. 3B) and the cable cover 520.

  Here, one surface of the cable cover 520 is formed along the inclined surface 121 a of the head case 110. Accordingly, a bent region H1 is formed in the gap between the inclined surface 121a of the cable housing portion 120 and the cable cover 520. The width of the gap between the inclined surface 121a of the cable housing portion 120 and the cable cover 520 is substantially equal to the outer diameter of the cable 512.

  In this case, even if a force pulling upward is applied to the cable 512, the cable 512 is sandwiched between the cable cover 520 and the inclined surface 121a of the head case 110 in the bent region H1. Thereby, the force directly applied to the connector part 511 via the cable 512 is reduced. Therefore, the connector part 511 is prevented from being detached from the connector fitting part 122.

  In addition, one surface of the cable cover 520 facing the cable housing portion 120 is continuous with the upper surface 520A while forming a gently curved surface. The inclined surface 121a of the cable housing portion 120 is continuous with the upper surface portion CA of the head case 110 while forming a gently curved surface as described above. That is, the gap between the inclined surface 121a of the cable housing portion 120 and the cable cover 520 is gradually enlarged upward. Thereby, even if tension is applied to the cable 512 from various directions, the cable 512 is prevented from being damaged by the edge of the upper surface portion CA of the head case 110 or the edge portion of the upper surface 520A of the cable cover 520.

  Further, an inclined surface 520 a is formed inside the lower end portion of the cable cover 520. When the cable cover 520 is fitted into the cable housing portion 120 from above, the inclined surface 520a of the cable cover 520 comes into contact with the edge portion of the upper surface of the connector portion 511, and the cable cover 520 moves downward. The inclined surface 520a of the cover 520 presses the connector portion 511 in the + Y direction. Thereby, the connector part 511 is reliably pushed into the connector fitting part 122.

(4) Operation of Head Part In the head part 100A having the above-described configuration, as shown in FIG. 6, an upward force is applied to the tip member 395 attached to the tip of the shaft part 300, whereby the shaft part 300 is It moves upward against the urging force of the spring 450.

  8 and 9 are diagrams for explaining the movement of the shaft portion 300. FIG.

  8 is a cross-sectional view of the head portion 100A in a state where no force is applied to the tip member 395, and FIG. 9 is a cross-sectional view of the head portion 100A in a state where the shaft portion 300 has moved to the maximum.

  As shown in FIG. 8, in a state where no force is applied to the tip member 395, the connecting pin insertion portion 322 of the shaft cap 320 causes the edge B <b> 1 of the through hole 110 b of the head case 110 by the downward biasing force of the spring 450. The shaft portion 300 comes to rest.

  At this time, the core 360 of the shaft portion 300 is almost not inserted into the bobbin 430.

  In this state, the distance between the lower end portion of the shaft connection portion 321 of the shaft cap 320 and the upper end portion of the locking member 250 is substantially equal to the length of the ball cage 230. As a result, the ball cage 230 is in substantially contact with the locking member 250.

  Hereinafter, the above-described state illustrated in FIG. 8 is referred to as an initial state of the shaft portion 300.

  Next, as shown in FIG. 9, in the state where the upward force is applied to the tip member 395 and the shaft portion 300 has moved upward as much as possible, the insulating cap 350 of the shaft portion 300 is connected to the bobbin 430 and the magnetic shield 440. The rotation stop pin 340 inserted into the connection pin insertion portion 322 of the shaft cap 320 abuts against the end surface of the notch 411 c of the substrate frame 410 while contacting the lower end portion.

  At this time, the core 360 of the shaft portion 300 is inserted from the lower end portion to the upper end portion of the bobbin 430, and substantially abuts on the protruding portion 380 a of the sealing member 380.

  The ball cage 230 in the outer cylinder 220 moves upward with the movement of the shaft 310 and abuts on the edge B1 of the through hole 110b of the head case 110.

  In addition, when a vibration etc. are added to the head part 100A, it may shift | deviate from the position which the ball cage 230 contact | abuts to edge B1. In this case, the operation of the ball cage 230 becomes unstable, and resistance is applied from the ball cage 230 to the shaft 310 when the shaft 310 moves.

  Therefore, in the present embodiment, when the shaft portion 300 is returned to the initial state shown in FIG. 8, the ball cage 230 is pushed downward by the shaft connection portion 321 of the shaft cap 320, so Move to the abutting position. That is, the position of the ball cage 230 is corrected by returning the shaft portion 300 to the initial state. This stabilizes the operation of the ball cage 230 and prevents resistance from being applied to the shaft 310.

  Based on such a moving amount (displacement amount) of the shaft portion 300 in the head portion 100A, a physical displacement amount such as the height of the object is measured.

  Specifically, the inductance of the transformer constituted by the bobbin 430 and the winding changes as the length of the portion of the core 360 inserted into the bobbin 430 changes according to the amount of movement of the shaft part 300. The change in inductance is output as a change in induced current. The current output from the transformer is applied to the circuit board 420 (FIG. 2) of the frame unit 400 (FIG. 2) and converted into a voltage (electric signal). In this way, the physical displacement amount of the object is converted into an electrical signal. This electrical signal is given to the CPU (not shown) of the main body 100B (FIG. 1).

  Based on the electrical signal, the CPU of the main body 100B calculates the amount of movement of the shaft 300 as a measured value of the physical displacement of the object. Further, the CPU determines whether or not the measured value is within a preset allowable range.

(5) Attachment When measuring an object with the contact displacement meter 100, the head portion 100A is fixed to various devices or support members such as a machine tool or an industrial robot. In that case, since the tip of the shaft portion 300 of the head portion 100A comes into contact with the object, it is necessary to securely fix the head portion 100A in order to obtain an accurate measurement value. On the other hand, when the head case 110 of the head portion 100A is fixed with a strong force, the head case 110 may be deformed or damaged.

  Therefore, in the present embodiment, the shaft cover portion 200 of the head portion 100A is securely fixed using the fixture described below.

  FIG. 10 is a perspective view showing a fixture of the contact displacement meter 100.

  As shown in FIG. 10, the fixture 800 includes a fastening member 820 and a nut 830. For the fastening member 820, for example, a metal such as SUS or a material such as synthetic resin is used. The plate-like member 810 may be fixed to the measurement location of the object, or may be fixed to a support member for supporting various devices or the head unit 100A. Alternatively, the plate-like member 810 may be a part of various devices or a part of a support member for supporting the head unit 100A. The fixture 800 is used for fixing the head portion 100 </ b> A to the plate-like member 810.

  FIG. 11A is a plan view of the plate-like member 810 in FIG. 10, and FIG. 11B is a side view of the plate-like member 810. FIG. 12A is a plan view of the fastening member 820 of the fixture 800, and FIG. 12B is a side view of the fastening member 820.

  As shown in FIGS. 11A and 11B, a circular through hole 810 a is formed in the center of the plate-like member 810. Further, a chamfered portion 810b is formed at the edge of the through hole 810a on the one surface side of the plate-like member 810 so as to form an angle θ1 with respect to the inner peripheral surface of the through hole 810a.

  As shown in FIGS. 12A and 12B, the fastening member 820 includes a cylindrical threaded portion 821, a cylindrical flexible portion 822, and an annular flange portion 823. The threaded portion 821 has the same inner diameter and outer shape as the bent portion 822, and is integrally formed at the lower end of the bent portion 822. The outer peripheral surface of the threaded portion 821 is threaded. The flange portion 823 is formed integrally with the upper end of the flexible portion 822, and has an inclined surface 823a that gradually spreads upward and obliquely upward from the outer peripheral surface of the flexible portion 822, and an outer peripheral surface 823b that is larger in diameter than the flexible portion 822. A plurality of curved concave portions 823c are formed on the outer peripheral surface 823b of the flange portion 823. The angle θ2 of the inclined surface 823a with respect to the axis of the fastening member 820 is substantially equal to the angle θ1 of the chamfered portion 810b with respect to the inner peripheral surface of the through hole 810a of the plate-like member 810.

  A plurality of split grooves 820a are formed at equiangular intervals around the axis of the fastening member 820. The dividing groove 820a extends in a direction parallel to the axis of the fastening member 820 from the upper end on the flange portion 823 side to the vicinity of the threaded portion 821.

  Next, a method for fixing the head portion 100A with the fixture 800 will be described.

  FIG. 13 is a cross-sectional view showing a state where the head portion 100A is fixed to the plate-like member 810 by the fixture 800. FIG. FIG. 14 is a cross-sectional view for explaining a fixing method of the head portion 100A by the fixture 800. FIG. In FIG. 14, only the outer cylinder 220 of the head portion 100A is shown.

  As shown in FIG. 13, the fastening member 820 is inserted into the through hole 810 a from one surface side of the plate-like member 810, and the outer cylinder 220 of the head portion 100 </ b> A is inserted into the fastening member 820. Further, the nut 830 is screwed into the threaded portion 821 of the fastening member 820 protruding from the other surface side of the plate-like member 810.

  Thereby, as shown in FIG. 14, the fastening member 820 is pushed in with respect to the plate-shaped member 810 as shown by the arrow M1. Thereby, an inward force is applied from the chamfered portion 810b of the plate-like member 810 to the inclined surface 823a of the fastening member 820 as indicated by an arrow M2. In this case, the bending portion 822 of the fastening member 820 bends inward, and the bending portion 822 holds the outer peripheral surface of the outer cylinder 220 so as to be tightened with an appropriate force. As a result, the deformation of the outer cylinder 220 of the head portion 100A is prevented and the head portion 100A is securely fixed to the plate member 810.

  As described above, the chamfered portion 810b is provided at the edge of the through hole 810a of the plate-like member 810, and the inclined surface 823a is provided at the flange portion 823 of the fastening member 820, whereby the head portion 100A is fastened by the fastening member 820. In addition, the head portion 100A is securely fixed to the plate-like member 810.

  In this case, since the flexible portion 822 can be deflected inward by the action of the flange portion 823 having a small axial length, the length of the fastening member 820 protruding from the plate-like member 810 can be reduced. . Thereby, the freedom degree of the attachment place of 100 A of head parts by the attachment tool 800 becomes large. Therefore, the mounting position of the head portion 100A can be easily changed, and the small head portion 100A can be easily and reliably fixed at a desired position.

(6) Effects of the present embodiment In the present embodiment, the shaft 310 is held by the ball cage 230 in the outer cylinder 220. Thereby, the contact area between the head case 110 and the shaft portion 300 is reduced. Therefore, wear of the head case 110 due to the sliding operation of the shaft portion 300 is suppressed.

  Further, when the shaft 310 slides in the outer cylinder 220, the friction between the outer cylinder 220 and the shaft 310 is reduced by the ball cage 230. Thereby, wear of the outer cylinder 220 is suppressed. Therefore, the long life of the expensive outer cylinder 220 is realized.

  As a result, the smooth sliding operation of the shaft portion 300 is ensured even during long-term use. As a result, the durability of the head portion 100A is improved, and the measurement accuracy of the contact displacement meter 100 can be maintained over a long period of time.

  Further, the rotation stop pin 340 inserted into the rotation stop pin insertion portion 322 of the shaft cap 320 is fitted into the rotation stop groove 111 formed in the head case 110, so that the shaft portion 300 slides in the axial direction. In addition to being allowed, rotation in the circumferential direction around the axis J is prevented.

  Thereby, since friction due to rotation in the circumferential direction around the axis J of the shaft portion 300 does not occur, wear of the shaft 310 and the outer cylinder 220 is further suppressed. Thereby, the durability of the head portion 100A is further improved.

  Further, since the rotation of the shaft portion 300 can be restricted by the rotation stop groove 111 of the head case 110 and the rotation stop pin 340 of the shaft portion 300, the processing of the outer cylinder 220 requiring high accuracy is simplified. Therefore, the manufacturing cost of the outer cylinder 220 can be reduced.

  In the present embodiment, since the magnetic shield 440 is disposed between the bobbin 430 and the spring 450, the magnetic influence on the bobbin 430 from the spring 450 is prevented. Thereby, the bobbin 430 can be disposed in the spring 450 without reducing the measurement accuracy of the contact displacement meter 100. Therefore, compared to the case where the spring 450 and the bobbin 430 are arranged in parallel in the axial direction, the space occupied by the spring 450 is reduced, and the head unit 100A can be downsized.

  Further, in the present embodiment, the head case 110 has the opening CD on one surface, and the circuit board 420, the bobbin 430, and the magnetic shield 440 are held in the board frame 410 from the opening CD into the head case 110. It is attached. Thereby, the assembly of the head portion 100A is facilitated as compared with the case where various members are individually attached to the head case 110.

  In addition, since the head case 110 is integrally formed from the upper surface portion CA, the lower surface portion CB, the back surface portion CC, the side surface portion CE, and the side surface portion CF, and the opening portion CD is provided on one surface, the waterproof property of the head portion 100A. Is easily secured by rubber packing or the like.

(7) Correspondence between each constituent element of claim and each part of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each part of the embodiment will be described, but the present invention is limited to the following example. Not.

  In the above embodiment, the through hole 110b corresponds to the hole, the head case 110 corresponds to the casing, the outer cylinder 220 corresponds to the holding member, the shaft 300 corresponds to the contact, and the ball cage 230 It corresponds to a rolling friction member, and the bobbin 430, primary winding and secondary winding correspond to conversion means.

  Further, the rotation stop groove 111, the locking portion 111a, and the rotation stop pin 340 correspond to a movement limiting mechanism, the rotation stop groove 111 corresponds to a groove portion, the rotation stop pin 340 corresponds to a projection portion, and the ball 231 is a spherical member. It corresponds to.

  The contact displacement meter according to the present invention can be used to detect the physical displacement of an object.

It is a block diagram which shows the structure of the contact-type displacement meter which concerns on this Embodiment. It is a disassembled perspective view of the whole head part. It is a figure which shows the detail of the head case of a head part. It is a figure which shows the detail of the head case of a head part. It is a figure which shows the detail of the board | substrate frame of a head part. FIG. 2 is a cross-sectional view of the head portion of FIG. 1 taken along line AA. It is sectional drawing in the ZX plane of the cable accommodating part shown to FIG. 2 and FIG. It is a figure for demonstrating the movement of a shaft part. It is a figure for demonstrating the movement of a shaft part. It is a perspective view which shows the fixture of a contact-type displacement meter. It is a figure which shows a plate-shaped member. It is a figure which shows the fastening member of a fixture. It is sectional drawing which shows the state by which the head part was fixed to the plate-shaped member with the fixture. It is sectional drawing for demonstrating the fixing method of the head part by a fixture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Contact displacement meter 100A Head part 100B Main body part 110 Head case 110a, 110b Through-hole 111 Rotation stop groove 111a Locking part 220 Outer cylinder 230 Ball cage 231 Ball 300 Shaft part 300
340 rotation stop pin 360 core 410 substrate frame 410
430 Bobbin 450 Spring 512 Cable 512
610 Back cover 620 Head case cover

Claims (6)

A contact displacement meter that measures the physical displacement of an object,
A casing having a hole on one side;
A cylindrical holding member attached to the hole of the casing;
A rod-shaped contact provided to protrude from the end of the holding member through the hole and the holding member from within the casing;
A rolling friction member provided between the holding member and the contact, and holding the contact in the holding member so as to be slidable in the axial direction by rolling friction;
A contact displacement meter provided in the casing and provided with conversion means for converting the amount of movement of the contact into an electric signal. The contact displacement according to claim 1, further comprising a movement limiting mechanism that allows the contactor to slide in the axial direction relative to the casing and prevents rotation of the contactor about the axial direction. Total. The movement restriction mechanism is
A groove provided in one of the casing and the contact along the axial direction of the contact;
The contact-type displacement meter according to claim 2, wherein the contact-type displacement meter is configured by a projection provided on the other of the casing and the contact and slidably fitted in the groove. The contact-type displacement meter according to claim 1, wherein the rolling friction member includes a plurality of spherical members rotatably provided between the holding member and the contact. The rolling friction member has a cylindrical body that rotatably holds the plurality of spherical members, and each of the plurality of spherical members protrudes from an inner peripheral surface and an outer peripheral surface of the cylindrical body. The contact displacement meter according to claim 4. The contact type displacement meter according to claim 1, wherein the holding member is press-fitted into the hole of the casing.

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