JPH0926302A - Contact-type displacement sensor and work measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring apparatus in which many contact-type sensors can be arranged per unit area and which can perform a measurement even when the pitch of measuring points is narrow. SOLUTION: In a block-shaped sensor unit 11, a first detection coil block 17 in which a plurality of detection coils 51 are buried in prescribed positions in a substrate 50, an exciting coil block 18 in which a plurality of exciting coils 71 are buried in prescribed positions in a substrate 70 and a second detection coil block 19 in which a plurality of detection coils 81 are buried in prescribed positions in a substrate 80 are stacked. In a state that guide blocks 16, 20 are arranged on both the surface and the rear surface, the respective blocks 17 to 19 are fixed to each other. A plunger 21 is passed through the coils 51, 71, 81 at the respective blocks 17 to 19 so as to be freely movable. The plunger 21 is used to incorporate a core 33 into a pipe 30, and a differential transformer is constituted so as to take out an output according to the position of the core 33 with reference to the coils 51, 71, 81.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type displacement sensor and a work measuring device suitable for measuring, for example, the shapes and dimensions of various works.

[0002]

2. Description of the Related Art A displacement sensor using a differential transformer has been conventionally known. For example, in the conventional displacement sensor 1 shown in FIG. 9, a rod-shaped core 3 is provided inside a cylindrical housing 2 so as to be movable in the axial direction, a contactor 4 is provided on one end side of the core 3, and a contact is made by a spring 5. The child 4 is biased toward the workpiece W to be measured. An excitation coil (primary coil) 6 and a pair of detection coils (secondary coils) 7 and 8 forming a differential transformer are arranged outside the core 3. The displacement sensor 1 has a primary alternating current applied to the excitation coil 6. When a voltage is applied, the generated magnetic flux interlinks with the detection coils 7 and 8, so that the difference between the electromotive forces generated in the detection coils 7 and 8 can be taken out as an output voltage (secondary voltage). If the position of the core 3 is at the neutral point with respect to the detection coils 7 and 8, the output voltage is almost zero, but if the position of the core 3 is displaced from the neutral point, the output voltage is changed according to the displacement amount. It has a linear output characteristic such as a large value. Therefore, if the relationship between the output voltage and the displacement amount of the core 3 is obtained in advance, the position of the core 3, that is, the displacement amount of the contactor 4 can be known based on the detected output voltage.

In order to measure the shape, size, etc. of a work using the displacement sensor 1, a plurality of displacement sensors 1 are mounted on a mounting substrate 9 as shown in FIG.
By contacting the measured surface of the work W, the shape, size, etc. of the work W are measured based on the output voltage of each sensor 1.

[0004]

When using the above-mentioned conventional contact type displacement sensor 1, the pitch of a plurality of measurement points is 2 mm.
In the case of a work measuring device that is narrower, coils 6, 7, 8
It becomes difficult to pass the wiring extending from the inside to the inside of the housing 2. Further, it becomes difficult to connect the external conductor from the electronic device outside the displacement sensor 1 to the displacement sensor 1. Furthermore, if the displacement sensor 1 itself becomes smaller, the housing 2 also needs to be made thinner. Therefore, the structure in which a large number of displacement sensors 1 are mounted on the mounting substrate 9 as shown in FIG. 10 lacks strength and durability, and is practically used. I can't stand it.

For the above reasons, it is difficult to arrange a large number of sensors 1 densely in a small area.
It is difficult to inspect one work (especially a small precision part) at many measurement points. In that case, even if the workpiece can be measured at a plurality of measurement points, the arrangement intervals of the sensors 1 become coarse. Therefore, in order to perform multipoint measurement, the measurement is divided into a plurality of steps and performed at different inspection stages. There is a need. For the above reasons, the conventional displacement sensor 1 is
It was difficult to use for multi-point measurement such as height.

Therefore, an object of the present invention is to provide a contact type displacement sensor capable of narrowing the interval between measuring points without sacrificing strength and durability, and a work measuring device using this sensor. is there.

[0007]

A contact type displacement sensor of the present invention developed to achieve the above object comprises a first coil block in which a first coil is embedded at a predetermined position of a first substrate, A second coil block having a second substrate, having a second coil embedded in a position corresponding to the coil, and fixed to the first coil block directly or in a state of being laminated on the first coil block via an insulating sheet; A pipe that passes through the centers of the first coil and the second coil and is movable in the thickness direction of the coil blocks; and a contactor that has a core built in the pipe and is provided on the tip side. A plunger projecting outside the coil block and a biasing means for biasing the plunger toward the work are provided.

When the plunger moves with respect to the first coil and the second coil, the output signal changes according to the position of the core inside the plunger. In this contact type displacement sensor, each coil is embedded in a plate-shaped coil block having a flat substrate as a main body, so that the positions of the first substrate and the second substrate are fixed in a state where the positions of the first substrate and the second substrate are accurately regulated. If so, even with an extremely small coil, the relative position of each coil can be accurately regulated, and the mounting state of each coil becomes stable.

Further, the work measuring device of the present invention has a first substrate in which a plurality of first detection coils are embedded at predetermined positions on the first substrate.
Of the detection coil block and a second substrate, and a plurality of exciting coils are embedded at positions corresponding to the respective detection coils and are fixed to the detection coil block directly or in a state of being laminated via an insulating sheet. It has an exciting coil block and a third substrate, and a plurality of second detecting coils are embedded at positions corresponding to the respective detecting coils and fixed in a state of being laminated directly on the exciting coil block or via an insulating sheet. Second detection coil block, a pipe movable through the centers of the first detection coil, the excitation coil and the second detection coil and in the thickness direction of each coil block, and a core built in the pipe. And a plurality of plungers, each of which has a contact and is provided on the tip side, protrudes to the outside of the coil block, and each plunger faces the workpiece. It is provided with a biasing means for energizing.

In the work measuring device having the above structure, the first
The second detection coil, the exciting coil, and the core form a differential transformer. That is, when the primary AC voltage is applied to the exciting coil, the generated magnetic flux interlinks with the first and second detection coils, so that the secondary voltage corresponding to the position of the core is obtained. Therefore, the position of the core, that is, the amount of displacement of the plunger can be obtained based on the detected value of the secondary voltage based on the relationship between the amount of displacement of the secondary voltage and the amount of displacement of the core obtained in advance.

In the work measuring device having the above structure, a large number of plungers can be densely arranged per unit area and arranged in parallel, and durability, strength, or manufacturing can be achieved even when the distance between the measurement points is narrower than 2 mm. It can be used as a practical sensor in terms of accuracy. And even if the size of the three types of coils (excitation coil and pair of detection coils) is small, each coil can be arranged in series according to the specified specifications, and even very small coils can satisfy the winding resistance and insulation. Wiring difficulties are also reduced.

For these reasons, in particular, simultaneous multipoint measurement with a measurement point pitch of 2 mm or less (for example, 0.5 mm or 1 mm) can be realized.
It can be used for shape inspection of leads and ball contacts of I connectors and the like, and is particularly suitable for shape inspection of small parts such as small electronic devices.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. The workpiece measuring device 10 shown in FIG. 2 has a block-shaped sensor unit 11
It has. The sensor unit 11 includes a plurality of contact displacement sensors 12 shown in FIG. 1 arranged in parallel in the surface direction of the surface to be measured of the work W.

The contact type displacement sensor 12 shown in FIG. 1 has a cap block 15, an upper guide block 16 and a first detection coil block 17 in order from the top in the figure.
In addition to the excitation coil block 18, the second detection coil block 19, and the lower surface side guide block 20, a plunger 21 movable in the vertical direction is provided.

The plunger 21 is replaceable with a long and thin pipe 30 made of a non-magnetic electrically insulating material or a metal having a low magnetic permeability such as stainless steel, and an abrasion resistant material inserted at the tip of the pipe 30. Contactor 31,
A rear end member 32 attached to the rear end of the pipe 30 and a rod-shaped core 33 accommodated inside the pipe 30 are provided. The core 33 is fixed to the inner surface of the pipe 30 by an appropriate fixing means such as an adhesive. As illustrated in FIG. 4, a plurality of the plungers 21 are arranged in one sensor unit 11 at a predetermined pitch (for example, two rows of five rows each, a total of ten rows).

A recess 35 is formed inside the cap block 15 for accommodating the rear end member 32 of the plunger 21 so as to be vertically movable. A spring 37 is housed in the recess 35 as an example of a biasing unit that biases the plunger 21 toward the work W downward. Further, the rear end member 32 is provided with a flange-shaped convex portion 38, and by abutting the convex portion 38 against the guide block 16, the plunger 21 can be stopped at a position lowered by a predetermined amount. There is.

The upper guide block 16 has a flat plate shape and has a guide hole 41 through which the plunger 21 is inserted. In the case of the sensor unit 11 shown in FIG. 4, since the number of the plungers 21 is 10, the guide holes 41 are also formed at 10 places. However, plunger 2
Since the number of 1's and the positions to be provided vary depending on the required specifications of the work measuring device 10, the number and positions of the guide holes 41 are not limited to the illustrated example. Positioning guide pins 4 are provided on both ends of the upper guide block 16.
2 are provided.

The plunger 21 is inserted through the guide hole 41 so as to be movable in the axial direction. In this case, since the plunger 21 moves while being in contact with the inner surface of the guide hole 41, the material of the guide block 16 is a resin having a small friction coefficient with respect to the plunger 21 and less wear (for example, fluororesin), or the guide hole 41. It is advisable to apply a low friction coating to the inner surface of the.

The first detection coil block 17 includes a flat plate-shaped first substrate 50 made of an insulating material, and a first detection coil 51 embedded in the substrate 50. The first detection coil 51 is located at a position corresponding to the guide hole 41, and is embedded in a posture in which it is erected in the thickness direction of the substrate 50 so that the axis of the coil 51 (coil axis) penetrates both upper and lower surfaces of the substrate 50. . The detection coil block 17 is manufactured as described below as an example.

As shown in FIG. 5, the coil 51 is embedded in a substrate material 55 made of an electrically insulating resin. As a method for embedding the coil 51, for example, a resin molding method is used in which a molten resin (substrate material 55) is poured into the mold while the coil 51 is arranged inside a molding mold. In the coil 51, a winding (coated wire) 57 is wound around a cylindrical bobbin 56 in advance, and an end 57 a of the winding 57,
57b is projected to the end face side of the coil 51. Further, the spacer 58 is inserted inside the bobbin 56.

After embedding the coil 51 in the substrate material 55 as described above, a part of the substrate material 55 is cut off at both ends of the coil 51 by machining as shown in FIG. Together with
The ends 57 a and 57 b of the winding 57 are exposed on the surface of the substrate 50.

As a manufacturing method other than the above resin molding, for example, a hole is formed in a predetermined position of a resin substrate 50 formed in a flat plate shape by a drill or the like, and the coil 51 is inserted into this hole.
After assembling, the coil 51 may be fixed by filling the hole with an adhesive.

Through the above steps, the ends 57a, 57 of the winding 57 are
After exposing b, the conductive portions 6 and 61 are attached to the surface of the substrate 50 as shown in FIG.
0, 61 and the ends 57a, 57b of the winding 57 are electrically connected. As a method of forming the conductive portions 60 and 61, for example, an appropriate means such as plating, vapor deposition or printing is adopted. The conductive portions 60 and 61 may be applied to the substrate 50 so as to have a predetermined pattern from the beginning, but after the conductive layer is uniformly applied to the entire surface of the substrate 50, unnecessary portions are removed by etching. Therefore, the conductive portions 60 and 61 having a predetermined pattern may be left.

Also, the spacer 58 is removed to remove the coil 51.
Is an air core, and both ends of the coil 51 are opened on both upper and lower surfaces of the substrate 50. Therefore, the plunger 21 can be passed through the center of the coil 51. With the detection coil block 17 manufactured as described above, the conductive portions 60 and 61 can be provided along both the front and back surfaces of the substrate 50, and as shown in FIG. It can be connected to the conductor 63.

On the other hand, the exciting coil block 18 includes a flat plate-shaped second substrate 70 made of an insulating material, and an exciting coil 71 embedded in the substrate 70. The exciting coil block 18 is manufactured through the same steps as the coil block 17, and conductive portions 72.73 are provided along the upper and lower surfaces of the substrate 70 as shown in FIG. This exciting coil 71 is also an air core, and the axis of the coil 71 is the substrate 70.
Is embedded so as to penetrate the upper and lower surfaces of the coil in the thickness direction, and the coil 7
The plunger 21 can be passed through the center of 1.

The second detection coil block 19 includes a third substrate 80 made of an insulating material and a second detection coil 81 embedded in the substrate 80. The second detection coil block 19 is also manufactured through the same steps as those of the first detection coil block 17, and conductive portions 82.83 are provided along the upper and lower surfaces of the substrate 80 as shown in FIG. . The second detection coil 81 is also an air core, and the coil 8
The first axis is embedded so as to penetrate both upper and lower surfaces of the substrate 80 in the thickness direction, and the plunger 21 can be passed through the center of the coil 81.

When the coil blocks 17, 18 and 19 are piled up, wiring (for example, conductive portions 61, 72, 73,
82) may come into contact with each other, each coil block 1 may be connected as necessary in order to prevent a short circuit between them.
Insulating sheets 85 and 86 made of an electrically insulating material may be sandwiched between 7, 18 and 19.

The lower guide block 20 is also flat and has a guide hole 88 through which the plunger 21 is inserted. In the case of the sensor unit 11 shown in FIG. 4, since the number of the plungers 21 is 10, the guide holes 88 are also formed at 10 places.

Each block 15 constructed as described above,
16, 17, 18, 19, 20 and insulating sheets 85, 86
Are stacked in the thickness direction, and the blocks 15 to 20 are fixed to each other by an appropriate fixing means such as adhesion or fastening with bolts. Since each of these blocks 15 to 20 has a flat plate shape, they can be firmly fixed to each other by adhesion, bolting, or the like, positioning between the blocks is easy, and the rigidity of the sensor unit 11 as a whole is high. High and sufficient mechanical strength can be obtained.

In the case of the illustrated example, through holes 90 to 96 for passing the guide pins 42 are formed in the blocks 16 to 20 and the insulating sheets 85 and 86, and the guide pins 42 are passed through the through holes 90 to 96. Each block 16-20
Positioning is performed so that the plunger 21 passes through the center of each coil 51, 71, 81.

The above three coil blocks 17, 18, 1
Since 9 has the same structure as each other, each coil 51, 7
Wire diameters and lengths of windings of 1,81 and substrates 50, 70,
If the sizes such as the thickness of 80 are made equal, the coil blocks 17, 18, and 19 can be commonly used, and the cost can be reduced.

The plunger 21 is movable in the vertical direction with respect to each of the blocks 16 to 20, and when the contactor 31 at the tip is not in contact with the work, the core 33 includes the coils 51, 71 as shown in FIG. , 81 so as to be located below the neutral point for the plunger 1 by the spring 37.
2 is urged downward, and the position on the descending side is restricted by the convex portion 38.

When the contact 31 comes into contact with the work and the plunger 12 rises and the plunger 12 is displaced to a predetermined position, the core 33 reaches the neutral point for each coil 51, 71, 81. The contacts 31 of the plurality of plungers 21 face a plurality of measurement points different from each other on the surface to be measured of the work, and enable simultaneous multi-point measurement of the work.

The wire diameters and lengths of the windings used for the pair of detection coils 51 and 81 and the excitation coil 71 are substantially the same, and the excitation coil 7 is placed between the detection coils 51 and 81.
By arranging 1's, a three-stage differential transformer is constructed. In this case, as in the equivalent circuit shown in FIG. 3, the detection coils 51 and 81 are half-folded and connected in series with opposite polarities in the middle, and the exciting coil 71 receives the primary AC voltage Ep.
Is applied, an output voltage (secondary voltage) Es having a magnitude corresponding to the position of the core 33 is obtained.

That is, when the AC voltage Ep is applied to the exciting coil 71, the generated magnetic flux interlinks with the detection coils 51 and 81, so that the electromotive force E _S1 generated in the detection coils 51 and 81,
The difference Es of E _S2 can be taken out as the secondary voltage. The secondary voltage Es is detected when the position of the core 33 is the detection coil 51,
It is substantially zero if it is at the neutral point with respect to 81, but when the core 33 is displaced from the neutral point, Es is changed according to the displacement amount.
It shows a linear output characteristic such that the value of becomes large. Therefore, by previously obtaining the relationship between the secondary voltage Es and the displacement amount of the core 33, the position of the core 33, that is, the displacement amount of the plunger 21 can be known based on the detected secondary voltage Es.

As shown in FIG. 2, the work measuring device 10 equipped with the sensor unit 11 has a moving means 100 for moving the sensor unit 11 relative to the work W held at a predetermined position (only a part thereof). (Shown). The moving unit 100 moves the sensor unit 11 in the vertical direction by an actuator (not shown) or the like. The sensor unit 11 may be fixed and the work W may be moved in the vertical direction.

Further, an arithmetic processing unit (controller) 110 using a microcomputer or the like is provided as a means for processing the detection signal (differential pressure between the detection coils 51 and 81) output from each displacement sensor 12. . The sensor unit 11 and the arithmetic processing unit 110 are connected to each other by a wire that supplies a primary AC voltage to the exciting coil 71 and an external conductor 63 that includes a wire for extracting a detection signal from the detection coils 51 and 81.

When measuring the workpiece W, each displacement sensor 1
When the moving unit 100 lowers the sensor unit 11 so that the second plunger 21 contacts the measurement point of the work W, the plunger 21 is displaced by an amount corresponding to the height of the measurement point of the work W. By processing the individual detection signals output from each sensor 12 by the arithmetic processing unit 110, the shape / dimension (thickness, height, etc.) of the work W can be obtained based on the displacement amount of each plunger 21. . The arithmetic processing unit 110 determines whether or not the work W has a predetermined shape and size, and displays the determination result on the display unit.

As shown in FIG. 8, the sensor unit 11 is used when the three-dimensional unevenness of the surface to be measured of the work W is large.
The amount of protrusion H of the pipe 30 according to the distance from the
1 Alternatively, by making the lengths H2 of the contactors 31 different from each other so that the tip heights of the contactors 31 are varied, the heights of the coils 51, 71, 81 are made uniform for each block 17-19. However, since the distances from the uneven measurement points to the contactors 31 can be made equal, all the plungers 21 can perform measurement within the working range.

Further, if the lengths of the replaceable contacts 31 are made different, the three coil blocks 17 can be replaced by replacing the contacts 31 even with respect to works having various irregularities. , 18, 19 can use the common ones.

[0041]

According to the contact type displacement sensor of the present invention, the conventional housing is not necessary, and even if the pitch between the plungers is narrow as in the case where a large number of plungers must be arranged per unit area. The coils, the plungers, and the like can be accurately arranged, the rigidity, strength, and durability are high, the positions of the coils can be accurately regulated, and wiring to the coils can be performed without any problem. For this reason, a large number of plungers can be densely arranged in a small area, and a small number of workpieces to be measured, particularly small workpiece shapes in which the pitch between the plungers is desired to be 2 mm or less, can be used at the same time. Measurement can be realized.

Further, by appropriately selecting the projecting amount of the pipe of the plunger or the length of the contact for a plurality of measurement points of a work having unevenness, the coil block can be used for a work having large unevenness. No need to replace.
Further, it is possible to use the first detection coil block, the excitation coil block, and the second detection coil block having the same configuration, and to simplify the structure and reduce the cost by sharing the coil blocks. be able to.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a sensor unit using a contact displacement sensor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a work measuring device using the sensor unit shown in FIG.

3 is a circuit diagram of a displacement sensor of the sensor unit shown in FIG.

FIG. 4 is an exploded perspective view of the sensor unit shown in FIG.

5 is a cross-sectional view showing a state in which a coil is embedded in a substrate material in a process of manufacturing the coil block of the sensor unit shown in FIG.

6 is a cross-sectional view showing a state where a part of the substrate material shown in FIG. 5 is removed.

FIG. 7 is a cross-sectional view showing a state in which a conductive portion is attached to the substrate material shown in FIG.

FIG. 8 is a cross-sectional view showing a usage example of the sensor unit shown in FIG.

FIG. 9 is a sectional view of a conventional contact displacement sensor.

FIG. 10 is a sectional view of a sensor unit using a conventional displacement sensor.

[Explanation of symbols]

 10 ... Work measuring device 11 ... Sensor unit 12 ... Displacement sensor 17 ... First detection coil block 18 ... Excitation coil block 19 ... Second detection coil block 21 ... Plunger 30 ... Pipe 31 ... Contact 33 ... Core 37 ... Spring (Biasing means) 50 ... First substrate 51 ... First detection coil 70 ... Second substrate 71 ... Excitation coil 80 ... Third substrate 81 ... Second detection coil

Claims (4)

[Claims] 1. A first coil block in which a first coil is embedded in a predetermined position of a first substrate, a second substrate, and a second coil block at a position corresponding to the coil.
A second coil block in which the coil is embedded and fixed to the first coil block directly or in a state of being laminated on the first coil block through an insulating sheet; and a second coil block passing through the centers of the first coil and the second coil and A plunger having a pipe movable in the thickness direction of each coil block and a core built in this pipe, and a contactor provided on the tip side protruding to the outside of the coil block, and the plunger facing the workpiece. A contact-type displacement sensor, comprising: 2. A first detection coil block in which a plurality of first detection coils are embedded in a predetermined position of a first substrate, and a second substrate, and a plurality of positions are provided at positions corresponding to the respective detection coils. An exciting coil block, in which an exciting coil is embedded and fixed to the detection coil block directly or in a state of being laminated via an insulating sheet, and a third substrate, and a plurality of first coil coils are provided at positions corresponding to the respective detection coils. A second detection coil block in which the second detection coil is embedded and fixed to the excitation coil block either directly or in a state of being laminated on the excitation coil block; and the first detection coil, the excitation coil, and the second detection coil. Of the coil having a pipe movable through the center of the coil block and movable in the thickness direction of each coil block and a core built in the pipe and provided on the tip side. A plurality of plungers projecting outwardly of the lock, the workpiece measuring apparatus characterized by comprising a biasing means for biasing towards the respective plungers in the work. 3. The wire diameters and lengths of the windings of the first detection coil, the exciting coil and the second detection coil are made equal to each other, and the first substrate, the second substrate and the third substrate are provided. 3. The work measuring device according to claim 2, wherein the pair of detection coil blocks and the excitation coil block are made common by making each size of each of them equal to each other. 4. The projection amount of the pipe of each plunger or the length of the contact is set to the height of the unevenness so that the distances from a plurality of measurement points of the uneven work to the contact of each plunger are equal to each other. 3. The workpiece measuring device according to claim 2, wherein the workpiece measuring devices are different from each other.