JPH02143102A - Snap type internal diameter measuring instrument - Google Patents

Abstract

PURPOSE:To improve the measurement accuracy by interposing a grease-like consistency member which gives specific slide resistance to a piston and a resistance inducing member made of viscous liquid, etc., between the slide contact surfaces of a cylinder and the piston. CONSTITUTION:The rightward moving speed of a spindle 52 is determined by the weight of a part which moves simultaneously with the spindle 52, the slide resistance corresponding to the shearing stress of the greaselike consistency member 16, and the difference in energizing force between a leaf spring 34 and a compression coil spring 68, and the energizing forces of the springs 34 and 68 are set properly to control the moving speed of the spindle 52 below a specific value. The leftward moving speed of the spindle 52 is determined by the rightward energizing force of the springs 34 and 68 and slide resistance generated by interposing the grease contactness member 16 between the slide contact surfaces of the piston 15 fitted to a plunger 17 and the cylinder 14 which comes into slide contact, and the sudden leftward movement of the plunger 17 is prevented. Consequently no read error is generated even when a digital encoder 58 is used to take a measurement with high accuracy.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention converts the radial displacement of a probe that can come into contact with the inner surface of a hole in a workpiece into the axial displacement of a spindle, and The present invention relates to an inner diameter measuring device that measures the diameter of a hole in a workpiece based on displacement in the axial direction, and particularly to a snap-type inner diameter measuring device having a snub-type operation means for forcibly moving the spindle forward and backward. [Prior Art] A snap-type inner diameter measuring instrument has been known as an inner diameter measuring instrument that can quickly and easily measure the hole diameter of an object to be measured. As such a conventional snap-type inner diameter measuring device, for example, as shown in Japanese Utility Model Application No. 57-175003, the amount of displacement of a spindle is detected by a dial gauge. That is, a dial gauge is supported at one end of the main body, and a measuring element that protrudes and retracts in the radial direction is provided at the other end. This gauge head is biased in the direction of protruding into the main body by a first spring with a relatively weak biasing force, and is brought into contact with the inner end of the gauge head to change the displacement in the radial direction and the axial direction. The first
A second spring having a larger biasing force than the second spring biases the main body in the direction of protruding from the main body. Therefore, the measuring element always protrudes from the main body due to the difference in urging force between the first and second springs. The other end of the spindle is brought into contact with the measuring tip of the dial gauge, and the protruding and retracting movement of the gauge head is transmitted to the dial gauge via the displacement converting means and the spindle, and the displacement amount of the gauge head is measured by the dial gauge. It is readable. In order to insert the probe of such an inner diameter measuring device into the inner surface of the hole of the object to be measured, it is necessary to immerse the probe into the main body. For this purpose, an operating lever serving as an operating means is rotatably supported in the middle part of the main body, and by gripping the lever, that is, snapping the spindle, the spindle is moved away from the displacement converting means against the second spring. As the probe is moved, the probe is displaced by the first spring in the direction of sinking into the main body. If the probe in this retracted state is inserted into the large direction of the object to be measured and the operating lever is released in this state, the second spring with a large biasing force will cause the spindle to move the probe to the radius again via the displacement converting means. The probe is made to protrude in this direction, and the probe comes into contact with the inner surface of the hole. The radial displacement of the probe in contact with the inner surface of the hole is read by a dial gauge as a displacement meter in the axial direction of the spindle. This read amount is compared with the amount of displacement of the probe when inserted into a ring gauge whose inner diameter is known in advance to obtain the hole diameter of the object to be measured. [Problems to be Solved by the Invention] Incidentally, in recent years, there has been a desire for the appearance of electronic types of spindle-type inner diameter measuring instruments due to demands for higher measurement accuracy, prevention of reading errors, addition of various functions, etc. It is rare. Therefore, between the main body and the spindle, there is an optical
It has been considered to employ displacement measuring means equipped with various types of digital encoders, such as magnetic and capacitive encoders. However, when measuring the hole diameter with a Kerr snap type internal diameter measuring device, the force to grip the operating lever is almost completely released, and the lever is only supported slightly, so the contact of the probe to the inner surface of the hole is difficult. It is necessary to strengthen the contact force to support the weight of the measuring instrument0. For example, when measuring the inner diameter of a hole formed in the vertical direction, if the contact force of the contact point against the inner surface of the hole is weak, the contact force of the contact point against the inner surface of the hole may be weak. Since the measuring instrument slides on the inner surface and falls, the contact force of the measuring element, that is, the biasing force of the second spring is inevitably large. Therefore, when the probe is moved by operating the lever and comes into contact with the inner surface of the hole, the spindle moves at high speed and is subjected to vibrations and shocks. Therefore, if a displacement measuring means equipped with a digital encoder between the main body and the spindle is simply adopted, reading errors will occur in the digital encoder due to high-speed movement of the spindle, vibration, vibration, etc., and the amount of displacement of the spindle will be The problem is that it cannot be detected accurately. By the way, in order to solve this problem, it is conceivable to increase the frictional force between the spindle and the main body when the spindle moves. However, if the frictional force due to contact is increased in this way, the biasing force of the second spring cannot be sufficiently transmitted to the gauge head, and the contact force of the gauge head against the inner surface of the hole is reduced to 20. Depending on the situation, the measuring instrument may not be able to be supported. SUMMARY OF THE INVENTION An object of the present invention is to provide a snap-type inner diameter measuring device that can accurately detect the amount of displacement of a spindle without reducing the force of contact of the probe against the inner surface of the hole. (Means for Solving the Problems) In order to restrict the movement of the spindle, the present invention provides a piston that is displaced in relation to the spindle, and also provides a cylinder that comes into sliding contact with this piston, and prevents the sliding movement between these cylinders and the piston. A resistance imparting member made of a grease-like consistency member, a viscous fluid, etc. that imparts a predetermined sliding resistance to the piston is interposed on the contact surface. a displacement measuring means having a digital encoder capable of measuring the amount of displacement of the spindle; a measuring element that can come into contact with the measuring element, a displacement converting means that converts the axial displacement of the spindle into a radial displacement and transmits it to the measuring element, and a displacement converting means that urges the measuring element to constantly contact the displacement converting means side. a first urging means that urges the spindle in a direction opposite to the measuring element side via the displacement converting means; and a stronger urging means that urges the spindle toward the displacement converting means and stronger than the first urging means. a second biasing element having a force and biasing the probe in the projecting direction against the first biasing means via the spindle and the displacement converting means;
of the members to which the urging force of the second urging means is applied, the spindle. A piston provided on a side member and displaced in relation to the spindle, a cylinder in sliding contact with the piston, and a resistance imparting member interposed between the sliding surfaces of these cylinders and the piston and imparting a predetermined sliding resistance to the piston. This is a snap-type inner diameter measuring instrument characterized by comprising: In the present invention, the piston that is displaced in relation to the spindle includes not only cases where it is provided on the spindle itself, but also cases where it is provided on a member that is provided separately from the spindle and moves in relation to the spindle. Furthermore, in the present invention, as the resistance imparting member, a grease-like consistency member or a viscous fluid is preferable, and a grease-like consistency member is particularly preferable. [Function] In this configuration, in order to measure the inner diameter of a hole, as in the conventional method, grasp the operating member of the second knob and immerse the probe, insert the probe into the hole in this state, and then operate the probe. When the operating means is released, the spindle tends to be displaced at high speed by the second urging means having a strong urging force, but the movement of the piston and cylinder which can be displaced in relation to the spindle Since the spindle receives sliding resistance due to the shear force of the resistance imparting member such as a grease-like consistency member or viscous fluid interposed between the two, the spindle moves at an appropriate speed and the contact point contacts the inner surface of the hole. There will be no vibration or shock when doing so. Therefore, the displacement of the spindle can be accurately detected by the second digital encoder. On the other hand, in a static state where the gauge head is in contact with the inner surface of the hole, the shearing force of the grease-like consistency member, viscous fluid, etc. acts as a force, so the biasing force from the second biasing means is applied directly to the gauge head. This ensures that the contact force of the probe against the inner surface of the hole is sufficiently large. (Example) Hereinafter, an example of the present invention will be described based on the drawings.The snap-type inner diameter measuring instrument 1 in this example is roughly divided into three parts. A middle-shaped handle case 12 on which the operating lever 11 is rotatably supported (the handle part 10 that rotates and the left side of the handle part 10 in the figure) can be attached to and detached from the other side via a connecting member 13. The displacement measuring device has a measurement hand 30 which is attached to the holder and has an elongated cylindrical head case 31, and a displacement measurement device which is installed in the old hand part IO at the center of the figure and has a flat bottomed cylindrical display case 51. The measuring instrument main body 2 is composed of the handle case 12, the head case 31, and the display case 51.The display case 51 has a diameter direction. A spindle 52 is supported so as to be able to move in the axial direction through the spindle 52. Balls 5354 are embedded in both left and right ends of the spindle 52 protruding from the case 51, with parts of the balls 5354 protruding, and are fixed integrally. An elongated main scale 5G having graduations on the μm order is fixed to a spindle 52 located inside the case 51 via a scale attachment member 55. A short index scale 57 having graduations on the order of 8 m is arranged, and a digital encoder 58 is constituted by the main scale 56 and the index scale 57. At this time,
The digital encoder 58 can be of any type, ie, optical, magnetic, electromagnetic, capacitive, etc. encoder. The index scale 57 is attached to a substrate 59 fixed to the case 51 via a bracket 60. Further, the circuit board 59 is provided with a circuit component 61 that can calculate the amount of relative movement between the main scale 56 and the index scale 57 and measure the amount of displacement of the main scale 56 and, by extension, the spindle 52. This circuit component 61 and
The main scale 56 and the index scale 57
The displacement measuring means 62 is constituted by a digital encoder 5 and 5. A shallow dish-shaped lid member 63 is rotatably attached to the portion of the display case 51 exposed from the handle case I2, and a liquid crystal display 64 is provided in the center of the lid member 63. ing. This display 64 is connected to the circuit component 61 via a flat cable 65. ! : The displacement amount of the spindle 52 calculated by the circuit component 6I can be displayed in inches or millimeters. In addition, as shown in FIG. 2, one member 63 includes a zero setting switch, a preset switch, a switch for setting measurement conditions such as inch/millimeter switching, and o N-O.
FF The first switch consisting of a switch for F, etc. +! ¥66
is provided. ll: In FIG. 1, a stop pin 67 is provided protruding from the end surface of the lid member 63 of the display case 51, and the rotation angle of the lid member 63 with respect to the case 51 is regulated by this stop pin 67. There is. The hand case 31 includes a measuring element 3 movable in a direction perpendicular to the axial direction of the spindle 52, that is, in a radial direction.
Three pieces 2 are provided at 120 degrees equidistant positions. Thin round shaft-shaped carbide tips 33 are fixed to the outer ends of these probes 32, respectively.
The cylindrical surface of No. 3 can come into contact with the inner surface of the hole 6 of the object to be measured 5. These probes 32 are each biased in the direction of retraction into the case 1 by a leaf spring 34, which is provided within the case 31 and serves as a first biasing means having a relatively weak biasing force. Further, a cone 35 as a displacement converting means movable along the axial direction of the spindle 32 is disposed inside the case 31, and a conical portion 35A provided at the tip of the cone 35 is provided with the temporary spring 34. Due to the biasing force, the tapered surface 32A provided inside the measuring element 32 is always brought into contact with the tapered surface 32A. On the other hand, the proximal end side of the cone 35 is brought into contact with the ball 53 of the spindle 52, whereby the axial movement of the spindle 52 is transmitted as the axial movement of the cone 35. The radial displacement of the probe 32 is changed in IQ and transmitted. Inside the handle case 12, one end is connected to a display case 51.
A cylindrical cylinder 14 screwed into the cylinder 14 is disposed. A piston 15 having a cylindrical shape with a bottom is in sliding contact with the cylinder 14 so as to be movable in the axial direction of the cylinder 4 and the spindle 52. A grease consistency member 16 as a resistance imparting member that imparts a predetermined sliding resistance to the piston 15 is interposed on the contact surface between the cylinder 14 and the piston 15. When the relative movement speed between the piston 15 and the piston 15 is zero, the shear stress is approximately zero, and as the relative movement speed increases, the shear stress increases. Preferably, it does not leak. A through hole 15A is formed in the bottom of the piston 15 to communicate the left and right sides of the bottom, and one end of a plunger 17 coaxially provided with the spindle 52 is fixed by an E ring 18. The other end of the plunger 17 is extended and supported by pawning a bush 19 provided on the cylinder 14. Between the bush 19 and the piston 15 is a leaf spring 34, which is the first biasing means.
A compression coil spring 20 is interposed as a second biasing means, which has a biasing force several orders of magnitude larger than the biasing force of . Due to the biasing force of the spring 20, one end of the plunger 17 fixed to the piston 15 is always biased to contact the spindle 52, and the probe 32 is moved through the spindle 52 and the cone 35 as a displacement converting means. It is designed to maintain a state of protruding from the head part case 31 against a leaf spring 34 as a first biasing means. The other end of the plunger 17 protruding from the bush 19 is provided with a collar portion 17A, and the operating lever rotatably supported on the handle case 12 via a support shaft 21 is provided on the collar portion 17A. The inner end of 11 is lockable. A plunger 17 is provided at the inner end of the operating lever 11.
A pair of opposing pieces 1.1 which are opposed to each other across the rim and have a wider interval than the collar +7A. A is formed,
Each opposing surface of this opposing piece 11A has a flange portion +7A.
A pair of pins 11B that can come into contact with the side end surface of the spindle 52
is provided. Further, a torsion coil spring 22 is interposed between the operating lever 11 and the handle case 12, and when the operating lever 11 is released, the opposing piece 11A
is in contact with the bush 19 to prevent the pin IIB from contacting the collar +7A. On the other hand, when the operating lever 11 is gripped, the bottle 118 comes into contact with the collar 11A, and moves the plunger 17 to the right in the figure against the spring 22. Furthermore, as shown in FIG. When the carbide tip 33 is in contact with the inner surface of the hole 6 and is slightly squeezed with a hand (not shown) to grasp the probe L, the bottle IIB is not in contact with the part 17A and the opposing piece 11
An intermediate state in which A also does not come into contact with the bush 19 can be obtained. Therefore, in this intermediate state, the lever 11
The gripping hole] does not act on the plunger 17 in any way, and does not affect the measuring force, that is, the contact force of the probe 32 against the inner surface of the hole. A second switch group 25 consisting of a hole 1 switch 23 and a data acquisition switch 24 is provided at the right end of the handle case 12 in the figure.
Another second switch group 25 consisting of a hold switch 23 and a data capture switch 24 is also provided near the display section 50 . At this time, the second
switch group 25 and a second switch group 25 near the display section.
The halt switch 23 and the data acquisition switch 24 are arranged at opposite positions with respect to the longitudinal center axis of the handle case 12. This allows the same type of switch to be placed in the hand whether the handle case 12 is held with the right end side up or the left end side up. For example, in this example, y! The hole switch 23 is located on the finger side to reduce erroneous operation. In FIG. 1, a compression coil spring 68 as a third biasing means is arranged between the wall surface of the 30 measurement heads of the display case 51 and the scale mounting member 55.
The spindle 52 can quickly follow the plunger 17 when the operating lever II is gripped. Next, the operation of this embodiment will be explained. To start measurement, the operator grasps the operating lever 1) and moves the plunger 17 to the right in the figure against the compression coil spring 20, which is the second biasing means. With this movement, spindle 5
2 follows the plunger 17 due to the action of the temporary spring 34 as the first urging means and the compression coil spring 6B as the third urging means, since the biasing force to the left by the plunger 17 is eliminated. to move to the right. Therefore, the cone 35 as a displacement converting means also moves to the right, and the measuring element 32
moves in the direction of sinking into the head part case 31. In this state, the probe 32 is inserted into a ring gauge (not shown) whose inner diameter dimension (nominal dimension) is known in advance, and then the operating lever 11 is released. When the operating lever 1 is released, the plunger 17 is moved to the left via the piston 15 by the action of the compression coil spring 20 as the second biasing means, and the spindle 52 and the coil are moved to the left.
-35, the probe 32 is made to protrude against the leaf spring 34 and the compression coil spring 6B. Due to this protrusion, the probe 32 comes into contact with the inner surface of the ring gauge and stops. In this state, the circumscribed circle of each carbide tip 33 of the three gauge heads 32 is exactly equal to the inner diameter dimension of the ring gauge, and in this state, the zero theft switch of the first switch group 66 is activated. to set the display on the display 64 to zero or to the inner diameter dimension of the ring gauge. Next, grip the operating lever II again to move the measuring tip 32 in the direction of recessing it into the head part case 3, and
Remove it from the ring gauge. While maintaining the state in which the operating lever 12 is held, the probe 32 is inserted into the 66 of the object to be measured 5, and the operating lever 11 is released again. As a result, as in the case of the ring gauge described above, the gauge head 32 is displaced in the projecting direction via the spindle 52 and the cone 35 by the biasing force of the compression coil spring 2o as the second biasing means. The carbide tip 33 attached to the outer end of the probe 32 comes into contact with the inner surface of the hole 6 of the measuring object 5 and stops. At this time, the amount of movement of the probe 32, that is, the amount of movement of the spindle 52 whose displacement is converted via the cone 35 as a displacement conversion means, is read by a digital encoder 58 consisting of a main scale 56 and an index scale 57. , and the inner diameter of the ring gauge is calculated by the circuit component 6] and displayed on the display 64. The displayed value on this display 64 is 7 times higher than the displayed value when measuring the inner diameter of the ring gauge.
If seven strokes are made, the difference is displayed as a plus or minus value, and on the other hand, when the inner diameter dimension of the ring gauge is preset, the difference is displayed as a value increased or decreased from the preset value. In the above-mentioned measurement, even if the operating lever 11 is held and released at high speed, the movement of the spindle 52 to the right or left in the figure will not be fast enough to cause a reading error in the digital encoder 5B. . That is, the speed of movement of the spindle 52 to the right is
2 and the weight of the parts that move simultaneously with 11q Consistency member 1
Since it is determined by the difference between the sliding resistance corresponding to the shear stress of 6 and the biasing forces of the temporary spring 34 and the compression coil spring 68, if the biasing forces of these springs 34 and 68 are set appropriately, The moving speed of the spindle 52 can be kept below a predetermined value. On the other hand, the leftward movement speed of the spindle 52 is determined by the spring 3 as the first and third biasing means.
It is originally determined by the difference between the rightward biasing force of the spindle 52 due to the biasing force of the compression coil spring 2o as the second biasing means and the leftward biasing force of the spindle 52 due to the biasing force of the compression coil spring 2o as the second biasing means. However, in this embodiment, since the grease-like consistency member 16 is interposed on the sliding surface 11 between the piston 15 attached to the plunger I7 and the cylinder 14 with which this piston 5 slides, Even if the biasing force is large, the sliding resistance corresponding to the shear force of the opening member 6 prevents the plunger 17 from moving at the second speed to the left, and therefore the leftward movement speed of the spindle 52 also changes excessively. This is not the case and is considered an appropriate value. According to this embodiment as described above, there are the following effects. That is, even if the biasing force of the compression coil spring 2o as the second biasing means that biases the probe 32 in the protruding direction via the spindle 52, the cone 35, etc. is increased, the contact between the piston 15 and the cylinder 14 is Due to the sliding resistance of the grease-like consistency member 1G interposed on the sliding surface, the spindle 52 will not be moved at an unduly high speed, and reading errors will not occur even if the electronic digital encoder 58 is used. There is no problem, and sufficient accuracy can be guaranteed. On the other hand, in a static state where the gauge head 32 is in contact with the inner surface of the hole, the shear stress of the grease-like consistency member 1G is approximately t, so the contact force of the gauge head 32 is not reduced by the consistency member 16. , snap-type inner diameter measurement to ensure sufficient size! When measuring S1, the inner diameter measuring device I does not move. In addition, the gutter groove for preventing sudden displacement of the plunger and jaw 17 can be provided at a low cost because a simple structure such as the piston 15 and the cylinder 14 is sufficient. Furthermore, since the grease-like consistency member 16 is in a state between solid and liquid due to the characteristics of grease, there is no stain-slip-like movement unlike sliding resistance due to solid friction, and there is no sliding resistance due to air dampers etc. Unlike other materials, it is not compressible, so it can provide stable sliding resistance. Furthermore, if a consistency member 16 that does not have a perfect score is used, there will be no leakage from the sliding surface of the consistency member 16, and stable operation can be achieved over a long period of time. Furthermore, since the through hole +5A is formed at the bottom of the piston 15, when the piston 15 moves, the air located on the left and right sides of the piston 15 can freely move through the through hole +5A, and the piston 15 moves to the right in the figure. During movement, the operating force by the operating lever 11 does not become unduly large, and when the piston I5 moves to the left in the figure, the second spring 2o
In addition, by making the spindle 52 and the plunger 17 separate, and by engaging the plunger 17 and the operating lever 11, the spindle 52 can be moved to the boot. Since the displacement is made via the 77 gear 17, the radial force exerted by the operating lever II on the plunger 17 is not transmitted to the spindle 52, and the amount of movement of the spindle 52 can be accurately detected. Moreover, since the spindle 52 is supported by the display case 51, the length of the spindle 52 can be shortened, and measurement errors due to thermal expansion or the like can be reduced. In addition, a torsion coil spring 22 is interposed between the operating lever 11 and the grip case 12, and the inner end of the operating lever 11 is always biased toward the sensor 19, so that the probe 32 is not exposed to the force. While in contact with the inner surface of the hole 6 of the measurement object 5,
Even if the operating lever 11 is not completely released for the purpose of supporting the measuring instrument 1, etc., the operating lever 11 and the plunger 17 will not be engaged with each other, and therefore the contact force of the measuring element 32 will not change. Operability can be improved. Furthermore, because the grease-like consistency member 16 is interposed, the probe 32 does not come into contact with the inner surface of the hole of the object 5 to be measured at a high speed, so even if the carbide chimp 33 is provided at the protruding end of the probe 32, the The durability of the probe 32 can be improved without damaging the object 5. Furthermore, since the display section 50 is provided on the measuring head 30 side of the measuring instrument main body 2, it becomes easy to read the measured values. Further, since the displacement measuring means 62 and the like that directly affect the measured values are not housed in the gripping portion 10, the spindle 52 and the like are not directly affected by thermal expansion caused by gripping the gripping portion 10. Furthermore, a first switch group 66 attached to the lid part (o 63) and used before starting measurement, and a second switch group #66 attached to the handle case 12 of the handle part 1o and used during measurement.
Since I placed it beyond 25 minutes, switch 'f4 I
FF operations are less likely to occur, and one-handed operation is possible, improving operability. Furthermore, since the halt switch 23 and the data capture switch 24 of the second switch group 20 are provided so as to face oppositely to the axis, the gripping direction of the gripping portion 1o can be changed.
It can be operated reliably even when measuring the I7 hole where the switch cannot be seen. Furthermore, since the lid member 63 is rotatably attached to the display case 5j by 1 m, the display 64 can always be placed in a position that is easy for the operator to see, regardless of the measurement posture, which also improves operability. can be improved. Also,
Close the inside of the measuring instrument body 2 as necessary.1. Since it can be set in a J-shaped form, it can fully demonstrate its waterproof, oil-proof, and dust-proof effects. Note that the present invention is not limited to the above embodiments,
Modifications within the scope of achieving the object of the present invention are included in the present invention. That is, in the above embodiment, instead of the grease-like consistency member +6 as the resistance imparting member, a relatively high viscosity fluid such as silicone oil may be used, and in short, the piston I5 and the cylinder I4
Any material may be used as long as it can be interposed between the piston 15 and apply tI dynamic resistance based on shear force to the movement of the piston 15. However, if the grease-like consistency member 16 is used, the above-mentioned effects can be obtained. At this time, when using a viscous fluid as the resistance imparting member, there is a possibility that the viscous fluid flows out from between the piston 15 and the cylinder 14 during use, so O-rings etc. are installed near both the left and right ends of the piston 15. It is desirable to provide a sealing means for this purpose.Also, for manufacturing reasons, the measuring instrument main body 2 is divided into three cases 12, 31, and 51, but these are not integrally formed. Also, as the displacement converting means, the cone 3 as described above may be used.
5, the probe 33 and the spindle 52.
It is also possible to use a V-shaped lever or the like, which has its tip end connected to each of the two, and whose bent portion is rotatably supported by the head case 3I. Furthermore, a cam or the like having an appropriately shaped shape can also be used. In short, the displacement converting means is the spindle 5
Any structure may be used as long as the axial displacement of 2 is transmitted to the probe 32 as a radial displacement perpendicular to the spindle.Furthermore, in the above embodiment, the spindle 52 and the plunger 17 were constructed separately. These may be made into one continuous member, but if they are made as separate members, the above-mentioned effects will be obtained. Therefore, the setting position of the piston 15 used to provide an appropriate sliding resistance is not limited to one provided on the plunger 17 separate from the spindle 52, but may be provided directly on the spindle 52. In short, Among the members to which the biasing force of the spring 20, which is the second biasing means, is applied, it is provided on the spindle 52 side, rather than on the two examples of the measuring instrument main body, such as the bushing 19. Piston 1 is a member that is displaced against
5 should be provided, and as an operating member,
It is not limited to the operation lever 11 as in the above embodiment, but if an appropriate means for enlarging the amount of movement such as the tooth IIT or the row is provided,
A push button type operation member etc. may be used.Furthermore, the first to third
The springs 34, 20, 68 as the biasing means may be any suitable spring type, such as a temporary spring, a coil spring, or a disc spring. Further, the shape, structure, etc. of the displacement measurement display section 50 are not limited to those in the above embodiments. For example, the lid member 63 does not necessarily need to be rotatably provided with respect to the display section case 51. The locking structure is not limited to the structure of the above-mentioned embodiment, but may be another structure. [Effects of the Invention] As described above, according to the present invention, it is possible to use a highly precise displacement measuring means such as an electronic type while maintaining sufficient contact force between the probe and the inner surface of the hole, thereby improving measurement accuracy. This has the effect of improving the FIG. 1 is a sectional view of an embodiment according to the present invention, and FIG. 2 is a front view of the embodiment. 1... Snap-type inner diameter measuring device, 2... Measuring device body,
IO...handle part, 1.1...operation lever +1A・
...Bin, 14...Cylinder, 15...Piston,
16... Grease-like consistency member, 20... Compression coil spring as second biasing means, 30... Measuring head,
32... Measuring head, 34... Temporary spring as first biasing means, 35... Cone as displacement converting means, 50
... Displacement measurement display section, 52 ... Spindle, 58.
... Digital encoder, 62... Displacement measuring means.

Claims (2)

[Claims] (1) A spindle supported by the measuring instrument body so as to be displaceable in the axial direction, a displacement measuring means having a digital encoder capable of measuring the amount of displacement of the spindle, and a radius perpendicular to the axial direction of the spindle attached to the measuring instrument body. a measuring element supported movably in a direction and capable of abutting against an inner surface of a hole in a workpiece; a displacement converting means for converting an axial displacement of the spindle into a radial displacement and transmitting the radial displacement to the measuring element; a first biasing means that biases the spindle so as to always contact the displacement converting means side and biases the spindle toward the side opposite to the measuring head side via the displacement converting means; a second biasing force having a stronger biasing force than the first biasing means and biasing the probe in the projecting direction against the first biasing means via the spindle and the displacement converting means; a snap-type operating means provided on the measuring instrument body for moving the spindle against the second biasing means;
A piston that is provided on the spindle side member among the members to which the biasing force of the second biasing means is applied and is displaced in relation to the spindle, and a cylinder that the piston slides into contact with;
A snap-type inner diameter measuring device characterized by comprising a resistance imparting member interposed between the sliding surfaces of the cylinder and the piston to impart a predetermined sliding resistance to the piston. (2) The snap-type inner diameter measuring device according to claim 1, wherein the resistance imparting member is comprised of a grease-like consistency member.