JP2019045273A - Measuring device and measuring system - Google Patents

Abstract

To provide a measuring device and a measuring system capable of suppressing an intrusion of foreign matters into the interior.SOLUTION: A measuring device 1 includes: a movable part 10 movably provided for a housing 50; a measurement part 30 for measuring a displacement of the movable part 10; a housing 50 for storing a rear end side of the movable part 10; a compression coil spring 63 for energizing the movable part 10 to the tip end side; and a stopper material 15 for defining a movable range of the tip end side in an axial direction. The pressure of an inner space 51s of the housing 50 is increased by supplying an air to the housing 50 of the measuring device 1. The stopper material 15 abuts against an inner side end surface 554 of a cap 55 with a spindle 13 moved to the tip end side by an air pressure from an energizing force by the compression coil spring 63 and the air pressure from an air tube 5. When the spindle 13 moves to the rear end side, the stopper material 15 is separated from an inner side end surface 554 so that the air is discharged from an air passage 555, and the foreign matters are prevented from entering an inner space 51s.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a length measuring device and a length measuring system.

There is known a length measuring device in which an axially movable spindle is brought into contact with an object to be measured and a displacement of the spindle from a reference position is detected.
For example, Patent Document 1 has a shaft having a spline groove and a contact provided at the tip, a scale provided on the shaft, an open end, and a ball spline bearing structure. By the bearing structure, the main body for supporting the shaft body so that the shaft body slides through the opening of the open end, a sensor which is disposed in the main body and reads the scale, the ring portion, and the inner peripheral side of the ring portion A convex portion provided in contact with the spline groove, and including a packing material provided at the open end of the main body, the convex portion of the packing material being a shaft with respect to a plane perpendicular to the axial direction A linear gauge is disclosed which is provided projecting from the ring portion so as to be inclined toward the contact side of the sensor.

Patent No. 5544129

Here, depending on the environment in which the length measuring device is used, foreign matter such as oil may intrude into the length measuring device. The presence of foreign matter inside the length measuring device is not preferable because the accuracy of displacement detection is reduced and the product life is shortened.
An object of the present invention is to provide a length measuring device and a length measuring system capable of suppressing the entry of foreign matter into the inside.

The invention according to claim 1 is characterized in that the spindle in which the tip end abuts on the measurement object, the housing for causing the spindle to movably protrude from the opening on the tip end, and the tip end side of the spindle abuts on the measurement object When the measurement is performed by detecting the position of the spindle by the detection unit and the detection unit that detects the position of the spindle, the air supplied to the inside of the housing is discharged to the outside from the opening at the tip end side. And an air discharge means for measuring the length of the object.
In the invention according to claim 2, when the tip of the spindle is not in contact with the object to be measured in the standby state before measurement, the air discharge means discharges the air supplied to the housing to the outside The length measuring device according to claim 1, wherein the length measuring device is sealed or suppressed.
The invention according to claim 3 is characterized in that, when air is supplied to the inside of the housing, the spindle is urged in a direction to push it out of the housing by an urging force by the air. It is a length measuring device of a statement.
The invention according to claim 4 further comprises biasing means for biasing the spindle in a direction to push it out of the housing in a state where air is not supplied to the inside of the housing, the spindle being When air is supplied to the inside of the case, it is urged in the pushing direction by the urging force of the urging means and the urging force of the air supplied to the inside of the case. It is a length measuring device according to claim 2.
The invention according to claim 5 is characterized in that the spindle in which the tip end abuts on the measurement object, the housing for causing the spindle to movably protrude from the opening on the tip end, and the tip end side of the spindle abuts on the measurement object And a detection unit for detecting the position of the spindle, which is held on the outer periphery of the spindle and moves along with the movement of the spindle, and when the spindle protrudes most to the tip end side of the housing, And a seal member in contact with an inner end face forming an internal opening communicated with the opening on the distal end side.
The invention according to claim 6 further comprises biasing means for biasing the spindle in a direction for causing the spindle to project toward the tip end side of the housing, wherein the spindle is a tip in a standby state before measurement. 6. A length measuring device according to claim 5, wherein the length measuring means projects most out of the case by the biasing means when not in contact with the object to be measured.
In the invention according to claim 7, the housing has a space capable of supplying air therein, and the sealing material in a state where the spindle is most protruded in a state where the air is supplied to the space. Is in contact with the inner end face and the release of air from the opening at the tip end to the outside is sealed or suppressed, and the spindle moves from the most projecting state to the rear end side of the housing and the sealing material 7. A length measuring device according to claim 6, wherein air is discharged to the outside from the opening on the tip end side by being separated from the inner end face.
The invention according to claim 8 is characterized in that the housing is provided with an axial surface seal portion that slides on the spindle at the tip end side of the internal opening, and elastically holds the axial surface seal portion. It is a length measuring device according to claim 5.
The invention according to claim 9 is characterized in that the housing is a seal holding portion for holding the axial surface seal portion, and the housing at a rear end side than a portion where the seal holding portion abuts the axial surface seal portion. 9. A length measuring device according to claim 8, further comprising an elastic portion provided between a body component and the seal holding portion, for elastically holding the axial surface seal portion.
The invention according to claim 10 is a length measuring system comprising the length measuring device according to any one of claims 1 to 9 and an air supply device for supplying air to the internal space of the length measuring device. .
The invention according to claim 11 is the length measuring system according to claim 10, further comprising: a controller for acquiring the information output by the length measuring device and displaying and outputting the information as a measured value.

  According to the present invention, it is possible to suppress the entry of foreign matter into the length measuring device.

It is a figure showing an example of the length measuring system to which this embodiment is applied. BRIEF DESCRIPTION OF THE DRAWINGS It is whole sectional drawing of the length measuring device to which 1st Embodiment is applied, (a) shows the state of the maximum protrusion of a spindle, (b) is the elements on larger scale. It is a graph which shows the relationship between pushing amount at the time of measuring by a measuring device, and measuring force, a horizontal axis is a spindle pushing position (mm), and a vertical axis | shaft is measuring force (N). It is explanatory drawing of operation | movement of the length measuring device to which 1st Embodiment is applied, (a) shows states other than the largest protrusion of a spindle, (b) is the elements on larger scale. It is whole sectional drawing of the length measuring device to which 2nd Embodiment is applied. It is the elements on larger scale of the moving part to which 2nd Embodiment is applied.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.
[Description of measuring system 100]
FIG. 1 is a diagram showing an example of a length measuring system 100 to which the present embodiment is applied.
The length measuring system 100 is for measuring the dimensions of an object to be measured such as a processed part, and is used, for example, in a part manufacturing plant. The length measuring system 100 is connected to the length measuring device 1 for detecting the length of the measurement object based on the displacement of the moving unit 10 described later, and the length measuring device 1, and performs various calculations and A display 2 as a controller that performs measurement, judgment of the finish of a workpiece at the time of processing, etc. and displays the result, and a cable 3 for electrically connecting the length measuring device 1 and the display 2; have. Furthermore, the length measurement system 100 includes an air supply device 4 that supplies air to the length measurement device 1 for pressing the moving unit 10 described later toward the measurement object, the length measurement device 1 and the air supply device 4 And an air tube 5 for enabling the flow of the air.

The length measuring device 1 has a moving unit 10 that is located on the tip side of the housing 50 and is movable in the axial direction with respect to the housing 50. The moving unit 10 has a probe 14 in contact with the measurement object at an end on the tip side. Further, the length measuring device 1 has a measurement unit 30 (see FIG. 2) which is provided inside the housing unit 50 and detects the displacement of the moving unit 10.
Then, the length measuring device 1 detects the amount of displacement from the reference position of the moving unit 10 by bringing the measuring element 14 of the moving unit 10 into contact with the measurement target, by the measuring unit 30 described later. In addition, although the measurement part 30 employ | adopts the structure which optically detects, as mentioned later, it is not restricted to this, For example, the structure which detects magnetically may be sufficient.

The display 2 allows the user to set initial parameters used for measurement using the length measuring device 1 and register various parameters. Further, in the display 2, setting conditions etc. are set to NO. By registering by (set number), SET NO. The specification of can easily call up the measurement conditions. This makes setup change easy. Further, on the measurement screen of the display 2, a reset operation for master alignment can be performed.
In the case of an absolute value display, for example, a state in which a machine-specific measurement value is displayed can be set as the display by the display device 2 with, for example, a state where the moving unit 10 of the length measuring device 1 is most out. In addition, the display unit 2 is provided with a pass / fail determination function that determines whether or not the measured value is within the range of the set pass / fail determination / rank determination, and performs display or output.

The display 2 can also be configured to connect a plurality of length measuring devices 1 and can perform multipoint operation display. Further, the display 2 can be provided with various interfaces for external input and output, and can be used according to the application.
Moreover, as a structure of the indicator 2, the inside of the length measuring machine 1 can also be made to have the same function. Moreover, it is also possible to communicate with the display 2 using various wireless communication functions without using the cable 3.

  The cable 3 is provided with a connector having a plurality of terminals such as an electrical signal on the rear end side of the housing 50, whereby a male connector is provided for the connector provided on the rear end side of the length measuring device 1 / It is detachable because of the female relationship.

The air supply device 4 is controlled by a control unit (not shown). Then, the air supply device 4 supplies air to the housing 50 of the length measuring device 1 through the air tube 5 to obtain the air pressure of the internal space 51s of the housing 50 (for example, see FIG. 2). To raise More specifically, the air supply device 4 supplies air when measuring the length of the measurement object by displacing the moving portion 10, and also when the moving portion 10 is not displaced. Supply of That is, the air supply device 4 continues to supply air after the power is turned on or in the measurement mode.
In addition, although the air supply device 4 adopts control which does not change when measuring and not measuring the air pressure to be supplied, it is not limited thereto, and control of changing the air pressure when measuring and not measuring An example is conceivable. For example, the air pressure at the time of measurement is increased more than when not measured, and the example which prevents foreign object intrusion of oil, swarf, etc. to internal space 51s (for example, see FIG. 2) of case 50 more certainly, This is an example in which the amount of released air when measuring is made lower than when not measuring the air pressure at the time of measurement.

  One end of the air tube 5 is connected to the air inlet / outlet of the air supply device 4, and the other end is connected to a connection provided on the rear end side of the length measuring device 1. Then, the air tube 5 forms a path of air between the air supply device 4 and the length measuring device 1. When air is supplied from the air supply device 4 through the air tube 5, the air enters the length measuring device 1, and when the air supply is stopped, the air in the length measuring device 1 is mainly on the air supply device 4 side. The air is returned to the atmosphere via the solenoid valve of the air supply device 4 and the like.

[Description of Length Measuring Device 1 According to First Embodiment]
Next, the length measuring device 1 which is a characteristic configuration of the first embodiment will be described using FIGS. 2 to 4.
FIG. 2 is an overall sectional view of the length measuring device 1 to which the first embodiment is applied, (a) shows a state of maximum projection of the spindle 13, and (b) is a partially enlarged view thereof. 2 (a) and 2 (b) will be simply referred to as FIG. Although a part of the length measuring device 1 has already been described, the construction and operation of the length measuring device 1 will be described again with reference to FIG.
As described above, the length measuring device 1 illustrated in FIG. 2 includes the moving unit 10 provided movably with respect to the housing unit 50, the measuring unit 30 that measures the displacement of the moving unit 10, and the moving unit 10. And a housing unit 50 for housing the rear end side. Further, the length measuring device 1 urges the first bearing 61 and the second bearing 62 which hold the moving unit 10 so as to be movable in the axial direction, and the direction (tip end side) of the moving unit 10 protruding from the housing 50 And a compression coil spring 63 functioning as an urging means.

[Description of moving unit 10]
The moving unit 10 has a sliding shaft 11 sliding in the axial direction with respect to the first bearing 61 and the second bearing 62, a glass scale 12 provided with a scale and integrally moving with the sliding shaft 11, a tip end A measuring element 14 is provided on the side and has a spindle 13 which moves with the sliding shaft 11 and a stopper member 15 which defines a moving range of the sliding shaft 11 and the tip end side in the axial direction of the spindle 13.
The spindle 13 has its tip end in contact with the object to be measured, and specifically, it abuts on the object to be measured via the probe 14 at the tip end.
The spindle 13 and the probe 14 are an example of a spindle. Further, a housing unit 50 which causes the spindle 13 to movably protrude from the opening 558 on the front end side, a stem 53 and a cap 55 described later are an example of the housing.

The sliding shaft 11 is a rod-like member extending in the axial direction. The sliding shaft 11 is provided so as to be movable relative to a base 51 described later of the housing 50 along the axial direction.
The sliding shaft 11 also has an opening 111 through which light traveling from the light emitting element 31 described later to the glass scale 12 passes, and a scale holder 112 holding the glass scale 12.
The tip side of a light emitting element 31 described later enters inside the opening 111. The opening 111 is formed by an elongated hole or the like extending in the axial direction, and enables the movement of the sliding shaft 11 in the axial direction in a state in which the light emitting element 31 is inserted.

  The glass scale 12 can transmit light and has a predetermined grid scale drawn thereon. The glass scale 12 is held by the slide shaft 11 and provided at a position sandwiched between a light emitting element 31 and a light receiving element 32 described later. The glass scale 12 is irradiated with light from the light emitting element 31. Further, the scale of the glass scale 12 is read by the light receiving element 32.

  The spindle 13 is a substantially cylindrical member extending in the axial direction. The spindle 13 is fixed to the tip end side of the sliding shaft 11 at the rear end side. That is, the spindle 13 is provided in a so-called cantilever state. In addition, the probe 14 of the spindle 13 has a portion formed in a substantially spherical shape. Then, the probe 14 forms a contact point on the spindle 13 with the object to be measured.

  The stopper member 15 is a member which is elastic and formed in a ring shape (annular shape). For the stopper member 15, for example, an O-ring made of resin such as rubber can be used. Then, the stopper member 15 is fitted into an annular recess 131 formed on the outer surface of the spindle 13. The stopper member 15 is held on the outer periphery of the spindle 13 together with the snap ring 16. The snap ring 16 restricts the axial movement of the stopper member 15. Further, the stopper member 15 is provided movably in the axial direction together with the spindle 13 inside the housing 50.

Furthermore, the spindle 13 moves to the tip side by the biasing force of the compression coil spring 63 and the pressure of air from the air tube 5, but the movement of the spindle 13 causes the stopper member 15 to contact the inner end surface 554 of the cap 55 described later. In the contact state, the spindle 13 is in the most extended state with respect to the housing 50, and this is the stop position of the spindle 13.
Thereby, when the spindle 13 is maximally projected, the discharge of the air supplied from the air supply device 4 (see FIG. 1) to the internal space 51s of the housing 50 via the air tube 5 is sealed or Be suppressed.
More specifically, in the state where the spindle 13 is most protruded, the stopper member 15 abuts on the inner end surface 554 of the cap 55, and the air discharge from the opening 558 on the tip side to the outside is sealed via the air passage 555 described later. Alternatively, the spindle 13 is moved to the rear end side of the housing 50 from the most protruded state, and the stopper member 15 is separated from the inner end surface 554, whereby air is discharged to the outside from the opening 558 on the front end side.
That is, when the spindle 13 is maximally protruded, the stopper material 15 abuts on the inner end surface 554, whereby the air discharged from the internal space 51s to the outside is completely sealed or the amount of the released air is suppressed. .

Incidentally, microscopically, the stopper material 15 has elastic deformation and has a width "at the time of the maximum projection of the spindle 13". More specifically, the stopper member 15 abuts on the inner end surface 554 of the cap 55 described later, and the maximum projection of the spindle 13 is defined while the stopper member 15 is elastically deformed by the biasing force of air or the compression coil spring 63.
Such "at the time of maximum projection of the spindle 13" includes a state in which the tip of the spindle 13 is not in contact with the object to be measured. Furthermore, “at the time of maximum projection of the spindle 13” is within the range of the elastically deformed state of the stopper member 15 due to the state where the spindle 13 is not pushed in but is in contact with the object to be measured Also includes the state in which the spindle 13 is moving.

Here, even if air is not supplied from the air tube 5 to the internal space 51s of the housing 50, the compression coil spring 63 urges the spindle 13 in the direction to push the spindle 13 out of the housing 50. It is an example of a force means. When air is supplied from the air tube 5, the spindle 13 is urged in the pushing direction by the urging force of the compression coil spring 63 and the urging force of the air supplied to the internal space 51s of the housing 50. Be done.
From another point of view, the compression coil spring 63 biases the spindle 13 in the direction of causing the spindle 13 to project toward the distal end side of the housing 50, and the spindle 13 projects most out of the housing 50 when it is maximally projected. It is
Further, as described above, the stopper member 15 is held on the outer periphery of the spindle 13 and moves along with the movement of the spindle 13. Further, the stopper member 15 is in contact with an inner end surface 554 forming an internal opening 557 communicated with the opening 558 on the front end side of the housing 50 when the spindle 13 protrudes most to the front end side of the housing 50. Yes, it is an example of a sealing material.

  In the first embodiment, the stopper member 15 is in contact with the inner end surface 554 of the cap 55 when the spindle 13 is maximally projected by the biasing force of the compression coil spring 63 and the pressure of air from the air tube 5. However, in the configuration not provided with the compression coil spring 63, the pressure in the direction of pushing out from the casing 50 is biased only by the pressure of the air from the air tube 5, thereby ensuring the contact state at the maximum projection of the spindle 13. An example is also conceivable.

Furthermore, when the spindle 13 moves toward the rear end side against the biasing force of the compression coil spring 63 and the air pressure from the air tube 5, the retaining ring 16 is provided on the inner protrusion 532 of the stem 53 described later. The abutment position of the spindle 13 with respect to the housing 50 is determined.
When the spindle 13 moves from the most extended state with respect to the housing 50 to the rear end side, the stopper member 15 does not contact the inner end surface 554 of the cap 55, and the air in the internal space 51s is the cap 55 and the spindle 13 Released from the space between
The portion that controls the air discharge including the stopper member 15 and the cap 55 is an example of the air discharge means.

[Description of Measurement Unit 30]
As shown in FIG. 2, the measurement unit 30 includes a light emitting element 31 that emits light and a light receiving element 32 that receives the light emitted by the light emitting element 31. The measuring unit 30 is held by the housing 50 and does not change its position relative to the housing 50.
For the light emitting element 31, an LED (Light Emitting Diode) or the like can be used. Then, the light emitting element 31 emits light of a predetermined wavelength toward the glass scale 12.
The light receiving element 32 is provided to face the light emitting element 31 with the glass scale 12 interposed therebetween. The light receiving element 32 has a sensor IC such as a photodiode or an image sensor, and reads the transmitted light transmitted through the glass scale 12. Then, the light receiving element 32 detects the information of the scale of the glass scale 12 obtained based on the change in the amount of light transmitted through the glass scale 12.
As described above, the measuring unit 30 detects the position of the spindle 13 by bringing the tip end side of the spindle 13 into contact with the measurement object, and is an example of a detection unit.

[Description of Case 50]
As shown in FIG. 2, the housing unit 50 includes a base 51 to which various components are attached, a stem 53 for housing the rear end side of the spindle 13, a cap 55 attached to the stem 53, and an exterior body covering the various components. And 59.

  The base 51 is attached with parts that do not move relatively when the moving unit 10 moves, such as the first bearing 61, the second bearing 62, the substrate of the light emitting element 31, and the exterior body 59. Moreover, the base 51 is formed in a substantially cylindrical shape, and forms an internal space 51s in which the air supplied from the air supply device 4 is accumulated. In the first embodiment, the rear end portion (rear end surface) of the sliding shaft 11 faces the internal space 51s of the base 51.

(Stem 53)
The stem 53 is fixed to the base 51. Further, the stem 53 is hollow and formed in a substantially cylindrical shape. The stem 53 has an outer protrusion 531 protruding outward in the radial direction, an inner protrusion 532 protruding in the radial direction, and a cap holding portion 533 provided on the distal end side.

The outer protrusion 531 contacts the end surface of the base 51 on the tip side in the first embodiment. Then, the outer protruding portion 531 suppresses the falling of the stem 53 with respect to the base 51.
The inner protrusion 532 receives the retaining ring 16 moving toward the rear end on the front end side.
The cap holding portion 533 forms a connection point with the cap 55. In the first embodiment, the cap holding portion 533 forms a screwing point. Then, the cap holding portion 533 holds the cap 55.

(Cap 55)
As shown in FIG. 2, the cap 55 is a member formed in a substantially cylindrical shape. The cap 55 forms a space through which the spindle 13 passes, and has an inner diameter difference between the first inner peripheral surface 551 and the second inner peripheral surface 556, and the inner diameters of the first inner peripheral surface 551 and the second inner peripheral surface 556. It has an inner end surface 554 demarcated and formed by a difference, and an inner opening 557 formed in the inner end surface 554 and in communication with the opening 558 on the front end side of the housing 50.
More specifically, the inner diameter of the first inner peripheral surface 551 and the inner diameter of the second inner peripheral surface 556 are both formed by the outer peripheral surface of the spindle 13 so as to allow the axial movement of the spindle 13. Greater than diameter. An air passage 555 as shown in FIG. 2B is formed by the gap between the inner diameter of the first inner peripheral surface 551 and the outer diameter formed by the outer peripheral surface of the spindle 13. The inner diameter of the second inner circumferential surface 556 is larger than the inner diameter of the first inner circumferential surface 551, and the inner diameter of the second inner circumferential surface 556 is the stopper member 15 fitted in the annular recess 131 of the spindle 13. The inner diameter of the first inner circumferential surface 551 is smaller than the outer diameter of the stopper member 15. An inner end surface 554 is defined by the inner diameter difference between the second inner circumferential surface 556 larger than the outer diameter of the stopper member 15 and the first inner circumferential surface 551 smaller than the outer diameter of the stopper member 15.

Then, since the inner diameter of the first inner peripheral surface 551 is formed to be smaller than the outer diameter of the stopper member 15, as shown in FIG. By contacting the end surface 554 or the internal opening 557, the air passage 555 is blocked by the elastic stopper member 15, and the release of air through the air passage 555 is sealed or suppressed. As described above, in order to suppress or seal the release of air, the stopper member 15 is brought into contact with the inner opening 557 almost at the same time as the stopper member 15 is brought into contact with the inner end surface 554 to directly close the air passage 555. It is. On the other hand, when a seal material curved in a skirt shape or a seal material whose cross section forms an inverted U-shape is used as the stopper material 15, for example, the stopper material 15 is an inner end surface In a state in which the air passage 555 is in contact with the internal combustion engine 554, the air passage 555 may be closed without direct contact with the internal opening 557, that is, it may be closed indirectly.
Even when the stopper member 15 is in the “blocked state”, it does not completely stop the flow of air, but is expressed as “suppressed” here. The state in which the stopper member 15 is pushed out toward the tip end and abutted against the inner end surface 554 and stopped is the maximum projection state in which the spindle 13 is most protruded.

  As described above, the inner diameter of the first inner peripheral surface 551 of the cap 55 is formed larger than the outer diameter formed by the outer peripheral surface of the spindle 13, and the air passage 555 is formed. In other words, the cap 55 forms an air passage 555 by facing the spindle 13 with a predetermined distance, and does not contact the spindle 13 in principle. The predetermined interval is determined based on the assembly accuracy of the spindle 13 so that the spindle 13 and the first inner circumferential surface 551 of the cap 55 do not contact even when the spindle 13 is eccentric. If there is no influence on the axial movement of 13, it may be in contact.

(Exterior body 59)
The exterior body 59 is formed in a substantially cylindrical shape as shown in FIG. 2 and provided so as to cover at least the base 51. Further, in the present embodiment, the exterior body 59 is the outermost boundary for filling the air supplied from the air supply device 4 (see FIG. 1) into the housing 50.

Subsequently, members provided between the moving unit 10 and the housing unit 50 will be described in detail.
[First Bearing 61 and Second Bearing 62]
The first bearing 61 and the second bearing 62 are held by the base 51. The first bearing 61 slidably supports the rear end side of the sliding shaft 11. Further, the second bearing 62 slidably supports the tip end side of the sliding shaft 11.

[Compression coil spring 63]
The rear end side of the compression coil spring 63 engages with the base portion 66 attached to the base 51, and the front end side of the compression coil spring 63 is inserted into the concave portion 11 a formed on the rear end side of the sliding shaft 11. Then, the compression coil spring 63 biases the moving unit 10 toward the tip end side. That is, the compression coil spring 63 acts to push the moving unit 10 out of the housing unit 50. Thereby, the state in which the stopper member 15 abuts on the inner end surface 554 of the cap 55 is maintained. Such state maintenance is also performed by the pressure of the air supplied from the air supply device 4 (see FIG. 1) to the internal space 51s of the housing unit 50 via the air tube 5.

FIG. 3 is a graph showing the relationship between the pressing amount and the measuring force when measured by the length measuring device 1, the horizontal axis is the spindle pressing position (mm), and the vertical axis is the measuring force (N). .
As shown in FIG. 3, the pressing amount and the measuring force have a linear function relationship. In the case where there is no air supply shown by the solid line in the same drawing, it is the case of the biasing force of only the compression coil spring 63, and the measurement force increases according to the spring constant of the compression coil spring 63 when the pressing amount increases.
Further, in the case of the air supply indicated by the alternate long and short dash line and the broken line, the urging force by the air is added to the urging force by the compression coil spring 63, so the measuring force is higher than in the case without the air supply. In the case indicated by the alternate long and short dashed line, it is 0.05 MPa, and in the case indicated by the broken line, it is 0.10 MPa.

[Function of Length Measuring System 100 and Length Measuring Instrument 1]
Next, the operation of the length measuring system 100 and the length measuring device 1 to which the first embodiment is applied will be described.
FIG. 4 is an explanatory view of the operation of the length measuring device 1 to which the first embodiment is applied, (a) shows a state other than the maximum projecting state of the spindle 13, and (b) is a partially enlarged view thereof It is. 4 (a) and 4 (b) will be simply referred to as FIG. Note that FIG. 4 shows the state of the length measuring device 1 in which the spindle 13 constituting the moving unit 10 is accommodated in the housing unit 50 as one of the states other than the maximum projecting state.

In the length measuring device 1, the housing 50 is fixed to a holder or the like (not shown). Moreover, the length measuring device 1 is arrange | positioned so that the tip of the axial direction of the moving part 10 may turn down, and the measuring element 14 may contact with a measuring object at the lowest end.
During the length measurement in the length measuring device 1, in the length measuring system 100, air supply to the length measuring device 1 by the air supply device 4 is started, and the display 2 is operated. In a state where the probe 14 of the spindle 13 is not in contact with the object to be measured before the start of the length measurement by the length measuring device 1, the stopper member 15 has the cap 55 by the biasing force of the compression coil spring 63 and the biasing force by air. It is in contact with the inner end surface 554, and the release of air from the air passage 555 is in a sealed or suppressed state. When the probe 14 of the spindle 13 of the length measuring device 1 contacts the object to be measured and the spindle 13 enters the housing 50, the stopper 15 separates from the inner end surface 554, and the air passage 555 seals the stopper 15 The air supplied from the air supply device 4 to the inside of the housing 50 is released from the tip end of the cap 55 and the air is blown out. As described above, in the state where the spindle 13 is in the housing unit 50, the entry of foreign matter from the tip of the cap 55 is suppressed by blowing air from the tip of the cap 55.

  Thus, when the length measurement by the length measuring device 1 is started, the moving unit 10 moves up and down (slids in the axial direction) in accordance with the position of the measurement object in the height direction. Move against. Due to the spring force of the compression coil spring 63 and the force of the supplied air, a force moving to the tip side always acts on the moving portion 10 (spindle 13). Thereby, in the length measuring device 1, the contact between the probe 14 and the object to be measured is maintained. Although the stopper member 15 moves together with the spindle 13, the inner diameter of the casing 50 facing the stopper member 15 in the moving path of the stopper member 15 such as the inner diameter of the second inner circumferential surface 556 of the cap 55 is the stopper member Since the diameter is sufficiently larger than the outer diameter of 15, the movement of the stopper member 15 does not increase the sliding resistance of the spindle 13.

Then, in the length measuring device 1, the scale of the glass scale 12 read by the light receiving element 32 is changed by the movement of the moving unit 10 with respect to the measuring unit 30. Then, the information of the scale read by the light receiving element 32 is output to the display 2 via the cable 3. The display 2 performs various calculations, and displays, for example, whether or not the object to be measured falls within a predetermined pass / fail determination / rank determination range, and displays the measured value of the dimension of the object to be measured.
In the present embodiment, "measurement" refers to reading a change caused by a change in the position of the spindle 13, and does not include the standby state where the switch is only turned on. Therefore, "before measurement" means before the position of the spindle 13 changes.

As described above, in the length measuring device 1 of the present embodiment, the air supplied to the internal space 51s of the housing unit 50 when the spindle 13 is moving to the rear end side at the time other than the maximum projection at the time of measurement. It is blown out from the tip side. Thus, air outside the casing 50 can be prevented from entering the internal space 51s of the casing 50, and intrusion of foreign matter into the internal space 51s of the casing 50 can be suppressed.
Generally, as the spindle 13 moves in the axial direction with respect to the casing 50, a pressure difference between the inside and the outside of the casing 50 is generated, so that the external air of the measurement environment easily intrudes into the internal space 51s. If the measurement environment is an environmental room where the presence of dust is suppressed, there is little adverse effect from the intrusion of external air, but for example, the place to measure the measurement object is in an environment such as a plant handling oil etc. Also, air containing the oil, oil itself, dust, etc. intrude into the internal space 51s of the housing 50. Air, dust, and the like containing this oil component cause the measurement accuracy to be reduced by the measurement unit 30, leading to shortening of the product life. In addition, for example, when the length measuring device 1 is used in a field of machining, metal swarf intrudes into the internal space 51s, which may cause a decrease in measurement accuracy or a decrease in product life.
However, according to the present embodiment, the air supplied to the inside of the casing 50 is released from the tip of the cap 55 at least when the length measuring device 1 is operated and the spindle 13 is moving. Thus, the entry of foreign matter into the inside of the housing unit 50 can be effectively suppressed.

  Further, when air is discharged to the outside, the air is blown to the outer peripheral surface of the spindle 13 so that foreign substances such as oil and chips adhering to the outer peripheral surface can be removed or reduced. That is, since the outer peripheral surface of the spindle 13 can be air-blown with air as the spindle 13 moves to the rear end side of the housing 50, the internal space 51s of the housing 50 can be maintained in a cleaner state. .

  In addition, for example, the cap 13 is designed to weaken the sealing force of the stopper member 15 or to increase the amount of air supplied to the inside of the casing 50 so that the cap 13 is in the most protruded state. It is also possible to release air from the tip of 55. According to this configuration, while the air is supplied to the length measuring device 1 by the air supply device 4, the air is always discharged from the tip of the length measuring device 1, and the inside of the length measuring device 1 is It is possible to maintain a cleaner state. Here, in order to weaken the sealing force by the stopper material 15, for example, the contact to the inner end surface 554 is weakened, or a gap is generated even if the contact is made. Consider the dimensional design of the

  Further, in the present embodiment, when the ring-shaped stopper member 15 having elasticity is inserted into the annular recess 131 of the spindle 13 and the stopper member 15 abuts on the inner end face 554 of the cap 55, Air release is sealed or suppressed, but is not limited thereto. For example, a ring-shaped stopper member 15 is provided on the inner end surface 554 of the cap 55, and the spindle 13 has a large diameter portion (for example, a flange or a portion having a different shaft diameter of the spindle) to be in contact with the stopper member When the large diameter portion 13 abuts on the stopper member 15 of the cap 55, there is also a mode in which the release of air from the opening 558 on the tip side to the outside is sealed or suppressed. Alternatively, the stopper material 15 may be omitted, and the large diameter portion of the spindle 13 may be in contact with the inner end surface 554 of the cap 55 to seal or suppress the air release. Furthermore, the inner end surface 554 itself in contact with the large diameter portion may be an elastic body.

[Description of Length Measuring Device 1 According to Second Embodiment]
Next, a length measuring device 1 according to a second embodiment will be described using FIGS. 5 to 6. The length measuring device 1 constitutes a part of the length measuring system 100.
FIG. 5 is an overall cross-sectional view of the length measuring device 1 to which the second embodiment is applied, and corresponds to FIG. FIG. 6 is a partially enlarged view of the moving unit 10 to which the second embodiment is applied.
In the second embodiment, the basic configuration is the same as the first embodiment, and thus the description of the common configuration is omitted. In the second embodiment, a swing mechanism for maintaining the sealing performance of the sealing material while reducing the sliding resistance of the spindle 13 is added to the front end side of the housing unit 50.

As shown in FIGS. 5 and 6, in the length measuring device 1 of the second embodiment, the seal cap 57 (an example of the seal holding portion) is held by the cap 55 as one of the swing mechanisms. In the second embodiment, the cap 55 loosely holds the seal cap 57 via the copying sealing material 64 (an example of the elastic portion). Further, an axial surface sealing material 65 (an example of an axial surface sealing portion) that slides on the spindle 13 to seal between the spindle 13 and the housing 50 is provided inside the seal cap 57. The copying sealing material 64 has a function of causing the axial center of the spindle 13 of the moving unit 10 to conform to the axial center of the housing unit 50.
As shown in FIG. 6, the cap 55 according to the second embodiment has a first inner circumferential surface 551, an inner end surface 554, and a second inner circumferential surface 556, as in the first embodiment. In addition to this, the copying seal holding portion 552 for holding the copying sealing material 64 and the connection portion 553 for forming the connection portion with the seal cap 57 are provided.

  The copying seal holding portion 552 has an annular recess opening radially outward. Then, the copying seal holding portion 552 is fitted with the copying seal material 64. The copying seal holding unit 552 holds the copying seal material 64 and also holds the seal cap 57 via the copying seal material 64.

  The connection portion 553 forms a connection point with the seal cap 57. In the second embodiment, the connection portion 553 makes a screw connection between the cap 55 and the seal cap 57, and the connection portion 553 is formed with an external thread.

(Seal cap 57)
The seal cap 57 is a member which is formed in a substantially cylindrical shape and has an opening 570 at the tip end side. In addition, the seal cap 57 includes the axial surface seal holding portion 571 for holding the axial surface seal member 65, the copy seal opposing portion 572 facing the outside in the radial direction of the copying seal member 64, and the connection point with the cap 55. And a cap connection portion 573 to be formed.

The axial face seal holding portion 571 has an annular recess opening radially inward. Then, the axial seal material 65 is inserted into the axial seal holding portion 571.
In the second embodiment, the distance H2 between the outer surface of the spindle 13 and the inner surface of the axial seal holding portion 571 is 90% or more with respect to the diameter D2 of the natural state cross section of the axial seal member 65. Is set to 100% or less.

  The copying seal facing portion 572 has an annular recess that opens radially inward. Further, the copying seal opposing part 572 is opposed to the copying seal holding part 552, and forms a region (hereinafter, copying copying material inserting part 55s) in which the copying seal material 64 is inserted. Then, the copying sealing material 64 is inserted into the copying sealing material insertion portion 55s. As a result, the seal cap 57 is held by the cap 55 via the copying sealing material 64 which is an elastic member.

  Furthermore, the distance H1 between the outer surface of the copying seal holding portion 552 and the inner surface of the copying seal opposing portion 572 (the radial width of the copying seal member insertion portion 55s) is the cross section of the copying seal 64 in a natural state. The diameter is set to be less than 90% with respect to the diameter D1.

The cap connection portion 573 forms a place for screw connection with the cap 55, and the cap connection portion 573 is formed with an internal thread.
Then, in the second embodiment, the cap connection portion 573 is not in close contact with the connection portion 553 but is connected to the connection portion 553 with a gap 57g. The gap 57g is formed by loosely fitting the screw connection between the cap 55 and the seal cap 57. However, it is also possible to form a predetermined linear gap as the gap 57g using another embodiment.
Furthermore, the seal cap 57 and the cap 55 are connected via the copying seal material 64 provided in the copying seal material insertion portion 55s. Then, the seal cap 57 and the cap 55 are connected in a loosely fitted state. As a result, the seal cap 57 can be displaced so as to tilt relative to the cap 55 with the copying seal material 64 as a base point.

  The seal cap 57 and the cap 55 may be connected in a loosely fitted state, and are not limited to the screw connection of the second embodiment. For example, the seal cap 57 and the cap 55 may be engaged in the axial direction so as not to be separated from each other, and the displacement (inclination) of the seal cap 57 may be permitted. Furthermore, the seal cap 57 and the cap 55 may be configured to engage only with the copying sealing material 64.

[Sealing material 64 for copying]
The copying sealing material 64 is a member having elasticity and formed in a ring shape (annular shape). As the copying sealing material 64, for example, an O-ring made of a resin such as rubber can be used. Then, as shown in FIG. 6, the copying sealing material 64 contacts the cap 55 radially inward and contacts the seal cap 57 radially outward. More specifically, the copying sealing material 64 is located between the cap 55 which is a component of the housing and the seal cap 57 on the rear end side of the portion where the seal cap 57 abuts on the axial surface sealing material 65. Provided.

  Further, the ratio C1 of the deformation rate to the diameter D1 of the cross section of the copying sealing material 64 in the natural state in the state of being inserted into the copying sealing material insertion portion 55s is set larger than 10%.

  Then, the copying sealing material 64 elastically holds the seal cap 57. As a result, in the length measuring device 1 of the second embodiment, the seal cap 57 (the housing 50) forms a state in which the axial surface sealing material 65 is elastically held.

[Axle seal 65]
The axial surface sealing material 65 is an elastic member formed in an annular shape. For the axial surface sealing material 65, an O-ring made of resin such as rubber can be used, for example. The axial surface sealing material 65 contacts the spindle 13 radially inward, contacts the seal cap 57 radially outward, and seals between the spindle 13 and the housing 50. The axial seal member 65 restricts the flow of air through the opening 570 when the air is supplied to the internal space 51s and the moving unit 10 is advanced. Further, the axial seal member 65 restricts the inflow of air when the air is about to flow into the internal space 51s through the opening 570.
Note that the sealing with the axial surface sealing material 65 in the second embodiment does not necessarily completely eliminate the entry and exit of air through the opening 570.

  The ratio C2 of the deformation ratio to the diameter D2 of the cross section of the axial seal material 65 in the natural state when the axial seal material 65 is inserted into the axial seal holding portion 571 is 0% or more and 10%. It is set as follows. As a result, the axial seal member 65 restricts the flow of air through the opening 570 into the internal space 51s of the housing 50. Furthermore, the axial surface sealing material 65 of the second embodiment allows sliding of the spindle 13 in the axial direction.

  Here, in the second embodiment, the ratio C2 of the deformation ratio of the axial surface sealing material 65 is the ratio of the deformation ratio of the conventional sealing material (hereinafter referred to as a normal sealing material) provided between the spindle and the housing. It is smaller than that. Generally, in order to achieve sealing performance, the ratio of the rate of deformation to the diameter of the natural state cross section of the normal sealing material in the attached state is, for example, greater than 10%. On the other hand, the axial surface sealing material 65 of the second embodiment has a smaller deformation rate as compared with the normal sealing material, and the sliding resistance to the spindle 13 is reduced as compared with the case where the normal sealing material is used. doing.

  In the length measuring device 1 of the second embodiment, the copying sealing material 64 does not contact the spindle 13 and does not affect the slidability of the spindle 13. Therefore, in view of the deformation rate, the ratio C1 of the deformation rate of the copying sealing material 64 is normally set in the same manner as the sealing material. Therefore, in the length measuring device 1 of the second embodiment, the ratio C2 of the deformation ratio to the diameter D2 of the cross section of the axial surface sealing material 65 in the natural state is the ratio D2 of the cross section of the copying sealing material 64 in the natural state. It is set smaller than the rate C1 of the deformation rate (rate C1> rate C2).

  Here, in the length measuring device 1 of the second embodiment, the spindle 13 may be decentered. Even in this case, the seal cap 57 holding the axial surface seal member 65 is loosely fitted to the cap 55 via the copying seal member 64. Therefore, the seal cap 57 can be tilted relative to the cap 55 with the copying seal material 64 as a base point. As a result, the seal cap 57 and the axial surface seal member 65 can be positioned following the spindle 13. That is, in the length measuring device 1 of the second embodiment, so-called "centering" by the seal cap 57 and the axial surface seal member 65 is automatically performed. As a result, the axial surface sealing material 65 is kept in contact with the spindle 13 and the seal cap 57, and the space between the moving portion 10 and the housing portion 50 is sealed.

  Further, as described above, since the axial seal material 65 can be aligned with the position of the spindle 13, in the length measuring device 1 of the second embodiment, for example, the axial seal material 65 is made stronger than the spindle 13. There is no need to tighten. For this reason, in the length measuring device 1 of the second embodiment, the sliding resistance that the spindle 13 receives from the axial surface sealing material 65 can be maintained low.

  According to the second embodiment, it is possible to suppress the leakage of the air supplied to the internal space 51s of the housing unit 50 by the axial surface sealing material 65. Depending on the use environment of the length measuring device 1, air may not be blown out from the tip of the length measuring device 1. However, according to the second embodiment, the air is blown out from the tip of the length measuring device 1. Can be eliminated and air blowout can be reduced. On the other hand, the air supplied from the air supply device 4 through the air tube 5 is filled in the internal space 51s of the housing unit 50, whereby foreign matter intrusion into the internal space 51s of the housing unit 50 is suppressed. As a result, the intrusion of foreign matter caused by the pressure difference between the inside and outside of the housing 50 caused by the vertical movement of the spindle 13 is reduced. Further, according to the second embodiment, even if the spindle 13 moves up and down when air is not supplied, foreign matter intrudes into the internal space 51s due to the pressure difference between the inside and outside of the housing unit 50. It is alleviated by the axial seal member 65.

  In the second embodiment, although the copying sealing material 64 and the axial surface sealing material 65 are used as the swing mechanism, the invention is not limited to this. For example, there is a modification in which an elastic member in which the functions of the copying sealing material 64 and the axial surface sealing material 65 are integrated is held by, for example, a cylindrical seal holding member. In such a modification, an integral elastic member, an axial surface seal portion having the function of the axial surface seal member 65, and an elastic portion having the function of the seal member 64 for copying on the rear end side of the axial surface seal portion; And a connecting portion connecting the two, and is formed in a tubular shape. Then, the outer periphery of, for example, the connection portion of the cylindrical elastic member may be held by the cylindrical seal holding member.

  Further, in the second embodiment, the copying sealing material 64 is used as the configuration in which the case unit 50 elastically holds the axial surface sealing material 65, but the configuration is not limited to this. For example, instead of the copying sealing material 64, a spring or a repulsive force of a magnet may be used. Furthermore, for example, the seal cap 57 itself that holds the axial surface seal member 65 may be made of an elastic material such as rubber.

DESCRIPTION OF SYMBOLS 1 ... length measuring device, 2 ... indicator, 4 ... air supply device, 13 ... spindle, 14 ... probe, 15 ... stopper material, 30 ... measurement part, 50 ... housing part, 51s ... internal space, 53 ... stem , 55: Cap, 63: compression coil spring, 100: length measurement system, 554: inner end face, 557: internal opening, 558: opening on the tip side

Claims (11)

A spindle whose tip abuts on an object to be measured;
A housing for movably projecting the spindle from the opening on the tip side;
A detection unit that abuts the tip end side of the spindle on the measurement object and detects the position of the spindle;
An air discharge unit that discharges the air supplied to the inside of the housing from the opening at the tip end to the outside when the position of the spindle is detected by the detection unit and measurement is performed;
The length measuring device characterized by having.   The air discharging means seals or suppresses the discharge of the air supplied to the casing to the outside when the tip of the spindle does not abut the object to be measured in the standby state before the measurement. The length measuring device according to claim 1.   3. The length measuring device according to claim 2, wherein the spindle is biased in a direction of pushing it out of the casing by a biasing force of the air when the air is supplied to the inside of the casing. And a biasing unit configured to bias the spindle in a direction to push the spindle out of the housing when air is not supplied to the inside of the housing.
When air is supplied to the inside of the housing, the spindle is urged in the pushing direction by the urging force of the urging means and the urging force of the air supplied to the inside of the housing. The length measuring device according to claim 2 characterized by things. A spindle whose tip abuts on an object to be measured;
A housing for movably projecting the spindle from the opening on the tip side;
A detection unit that abuts the tip end side of the spindle on the measurement object and detects the position of the spindle;
While being held on the outer periphery of the spindle and moving along with the movement of the spindle, when the spindle protrudes most to the tip end side of the housing, an internal opening communicating with the opening on the tip end side of the housing is formed A sealing material that contacts the inner end face
The length measuring device characterized by having. And a biasing means for biasing the spindle in a direction to project the spindle toward the tip end side of the housing.
The length measurement according to claim 5, wherein the spindle protrudes most from the housing by the biasing means when the tip is not in contact with the measurement object in a standby state before measurement. vessel.   The housing has a space capable of supplying air to the inside, and in a state where the air is supplied to the space, the seal material abuts on the inner end surface in a state where the spindle is most protruded and the tip is the tip The release of air from the side opening to the outside is sealed or suppressed, and the spindle moves from the most projecting state to the rear end side of the housing, and the sealing material is separated from the inner end surface to cause air to flow. 7. The length measuring device according to claim 6, wherein the length measuring device is discharged to the outside from the opening on the tip side.   The length measurement system according to claim 5, wherein the housing includes an axial surface seal portion sliding on the spindle at the tip end side of the internal opening, and elastically holds the axial surface seal portion. vessel.   The casing is a seal holding portion for holding the axial surface seal portion, and a constituent member of the housing and the seal holding portion at a rear end side of a portion where the seal holding portion abuts the axial surface seal portion 9. The length measuring device according to claim 8, further comprising: an elastic portion provided therebetween, and elastically holding the axial surface seal portion. The length measuring device according to any one of claims 1 to 9,
An air supply device for supplying air to the internal space of the length measuring device;
The length measuring system characterized by having.   11. The length measuring system according to claim 10, further comprising: a controller that acquires the information output by the length measuring device and displays the information as a measured value.

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