JPS6315521B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a micrometer that measures dimensions such as length and thickness of an object by moving and displacing a spindle.

Conventionally, the most common micrometer has a female thread that is machined with high precision on an inner sleeve that is fixed to the main frame side, and a male thread of a spindle that is also machined with high precision is screwed into this female thread, and it is fixed integrally to this spindle. This is a so-called screw-feed micrometer that measures an object by rotating a spindle with a thimble. Such a screw-feed micrometer has a nearly sealed internal structure including the screw, so it is highly dust-proof, and
This has the advantage that the self-locking action of the screw ensures that the object to be measured is clamped. However, since the entire spindle rotates as a unit due to the rotation of the thimble, the tip of the spindle rotates during measurement operations, which is difficult to do when measuring highly flexible materials such as soft plastic plates. This method is not suitable for measuring such materials because it causes wrinkles and the like on the object to be measured.
In addition, the tip of the spindle comes into contact with the object to be measured while rotating, and this may cause wear between the object to be measured and the spindle, as well as torsional force acting from the spindle on the object. This was not desirable in terms of maintaining accuracy measurements.

By the way, various structures have already been proposed for so-called linear micrometers in which the spindle does not rotate even when the thimble is rotated, but moves and displaces. The structure is complicated, with an intermediate cylindrical body provided between the thimble and frictional engagement means, spring biasing means, etc., and in particular, such a complicated mechanism must be built into the thimble. Therefore, the thimble had to have a large diameter, making it unsuitable for micrometers, which are generally small and often operated with one hand.

In addition, a spindle is provided that is keyed to the frame in the rotational direction and can be moved back and forth in the axial direction, and a filler metal is press-fitted into a recess provided at the rear end of the spindle. A small diameter part is provided at the tip of the male threaded body placed in, and a steel ball is embedded in the tip of this small diameter part,
A micrometer is known in which this steel ball is brought into contact with the filler metal, and a thrust bearing is coupled between the small diameter part and the recessed part of the spindle (Jikkosho).
40-23426). However, in this conventional example, in order to perform accurate measurements, the contact point between the steel ball and the filler metal must be aligned with the axis of the spindle and the male threaded body, but in order to do this, the filler metal must be placed on its end surface. is accurately positioned and press-fitted into the spindle so that it is perpendicular to the axis of the spindle, and
There are problems in that it is difficult to process and assemble the micrometer, as the male screw body must be arranged so that the tip of the steel ball is on the axis of the spindle. Furthermore, the filler metal is brought into contact with the steel ball, but since the radius of curvature of the steel ball is small, as the male screw body moves back and forth repeatedly, the steel ball or the filler metal is likely to become dented due to wear, etc. There is also the problem that the position of the spindle and the male threaded body may deviate, or the male threaded body may not push the spindle straight, resulting in a decrease in measurement accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a linear micrometer that has a simple structure, in particular can have a small thimble diameter, maintains measurement accuracy, and is easy to assemble.

Therefore, the present invention replaces the spindle, which was conventionally composed of one shaft member, with a first spindle and a second spindle arranged coaxially with each other.
A thimble is fixed to the first spindle, the first spindle is screwed onto the main body frame side so as to be movable in the axial direction, and the second spindle is fixed to the main body frame so as to be movable in the axial direction. A stepped protrusion is provided on the first spindle so as to be movably supported, and an angular bearing that supports an axial load is fitted onto the stepped protrusion, and the angular bearing is attached to the stepped protrusion. and a nut screwed onto the small diameter portion of the tip, forming a concave portion in the second spindle, and having a conical tapered surface in the concave portion, the top of which is located on the axis of the second spindle. Fitting holes are provided in succession, and a tapered part is held in the fitting hole with a predetermined gap in the circumferential direction between the first spindle and the second spindle, and a tapered part abuts the tapered surface at one end, and a tapered part at the other end that contacts the tapered surface. a substantially cylindrical contact body each having a spherical contact surface with a relatively large arc that abuts the first spindle and extends to the end edge; The two spindles are connected by a connecting mechanism including a retaining ring that contacts the angular bearing from the side, and the connecting mechanism allows the two spindles to rotate relative to each other and cannot be separated from each other in the axial direction.

Accordingly, in the present invention, when the thimble is rotated, the first spindle moves in the axial direction with respect to the main body frame, but the axial movement accompanying the rotation of the first spindle is caused to move in the second spindle with rotational movement. This is the result of an unprecedented axial movement. At this time, when the first spindle moves away from the second spindle, the angular bearings interposed in both spindles are held between the stepped part of the stepped shaft, the nut, and the retaining ring, and their movement is restricted. Therefore, relative displacement in the axial direction of both spindles is difficult.On the other hand, when the first spindle moves toward the second spindle, both spindles move along the tapered part of the contact body and the tapered surface of the insertion hole. The contact body is positioned on the same axis by centripetal action, that is, the contact body is positioned so that the contact point between the tip of the stepped protrusion protruding from the first spindle and the contact surface is located on the axis of both spindles. relative displacement is difficult. In addition, since a spherical contact surface with a relatively large arc is formed on the first spindle side of the contact body, even if the first spindle is moved back and forth repeatedly, the contact surface or the tip of the stepped protrusion that comes into contact with it will wear out. It becomes difficult for depressions to occur, and therefore,
Even when the micrometer is used for a long period of time, the relative displacement and straightness of the two spindles can be maintained, and a decrease in measurement accuracy can be prevented. Furthermore, when assembling the micrometer, it is sufficient to insert the contact body into the insertion hole having a conical tapered surface, and there is no need to position and fix the contact body to the first spindle.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the overall structure of an embodiment of a micrometer according to the present invention. In this figure, one end of the main frame 1 is formed into a U-shape, and an anvil 3 having a carbide tip 3A is fixed to the inner surface of one end of the U-shaped part 2 on the opening side. Frame covers 4 are attached to both sides of the shaped portion 2. The other end of the main body frame 1 is a cylindrical portion 5 that is oriented laterally in the figure, and this cylindrical portion 5 is integrally formed with the other end of the U-shaped portion 2.

One end of a cylindrical outer sleeve 6 is fixed to the right edge of the cylindrical portion 5 in the figure by adhesive or the like, and a sleeve scale 7 is formed on the outer peripheral surface of the outer sleeve 6.

A cylindrical inner sleeve 8 is fitted into the outer sleeve 6 and the cylindrical portion 5, and the cylindrical portion 5
The inner sleeve 8 is prevented from rotating around the cylindrical portion 5 by a set screw 9 that is threadedly fitted from one side of the inner sleeve 8 . Note that the tip of the set screw 9 projects further inward from the inner circumferential surface of the inner sleeve 8 by a predetermined amount. The other end of the inner sleeve 8 extends further to the right in the figure from the right end of the outer sleeve 6, and a slot groove 11 is formed in this end. Further, a taper nut 12 is screwed onto this end, and the inner diameter of a female threaded portion 13 formed on the inner peripheral surface of this end can be adjusted depending on the screwing position of the taper nut 12.

The female threaded portion 13 has a male threaded portion 1 that is machined with high precision over substantially the entire length of the outer peripheral surface of the first spindle 15.
6 are screwed together, in other words, the main body frame 1
The first spindle 1 is connected to the first spindle 1 through the outer sleeve 6.
5 are screwed together. In addition, these both threaded parts 1
3 and 16 are screwed together with high precision without play or the like by adjusting the tightening of the taper nut 12. A thimble 17 is tapered fitted to the right end of the first spindle 15, and this thimble 17 has a built-in ratchet mechanism and is connected to the first spindle 15 by a knob 19 screwed into the right end surface of the first spindle 15 by a threaded portion 18. Fixed. Further, the thimble 17 slidably surrounds the outer sleeve 6, and its left edge in the figure is connected to the first spindle 1.
5 and the inner sleeve 8, it is always located on the outer circumference of the outer sleeve 6, and a thimble scale 2 is provided on the circumferential surface of the left end side.
1 is formed.

A protruding shaft 22 having a substantially small diameter round shaft is protruded from the left end of the first spindle 15. It is inserted into the recessed part 25 which has.
The second spindle 24 is slidably fitted and supported by the inner sleeve 8 and is movable coaxially with the first spindle 15.
A locking groove 26 is formed along the longitudinal direction on one side of the spindle 24, and the tip of the set screw 9 is slidably fitted into the locking groove 26.
This prevents the second spindle 24 from rotating. Further, a carbide tip 24A is provided at the tip of the spindle 24, and a clamp screw 23 for appropriately clamping the second spindle 24 is attached to the cylindrical portion 5.

As shown in an enlarged view in FIG. 2, the protruding shaft 22 has a small diameter portion 27 on the distal end side and a large diameter portion 28 on the proximal end side.
The small diameter portion 27 is formed into a stepped round shaft shape.
An angular bearing 29 is fitted into the angular bearing 29 . The bearing 29 is composed of an inner race 31, an outer race 32, and a plurality of rolling balls 33 interposed between the races 31 and 32. inner lace 3
1 includes a relatively deep holding groove 3 that holds each rolling ball 33 by coming into contact with the peripheral surface of each rolling ball 33 on the left side in the figure.
1A is formed in the outer race 32, and a relatively deep holding groove 32A is formed in the outer race 32 to contact the circumferential surface of each rolling ball 33 on the right side in the figure, and between these grooves 31A and 32A, each of the above-mentioned rolling balls 32A is formed. The balls 33 are each freely rollable and are held firmly enough not only from the top and bottom directions in the figure but also from the left and right directions. The rolling balls 33 are maintained at a predetermined distance from each other along the circumferential direction by a retainer (not shown).

The inner race 31 is fixedly clamped between the stepped portion of the protruding shaft 22 by a nut 34 screwed from the tip side of the small diameter portion 27, and the outer race 32 is supported on the inner peripheral surface of the recess 25 on its outer peripheral surface. At the same time, a ring-shaped presser ring 35 through which the large diameter portion 28 is movably inserted is abutted on the right edge of the outer race 32.

The tip of the small diameter portion 27 is a flat portion perpendicular to the axial direction of the first spindle 15, and this flat portion is machined to be extremely smooth with high precision. Further, a contact body 37 is in contact with this plane portion. Contact body 37
is formed into a substantially short cylindrical shape, and is rotatably held in a fitting hole 38 formed at the bottom of the recess 25 . The bottom of the insertion hole 38 is a conical tapered surface 38A whose top is located on the axis of the second spindle 24, and one end surface of the contact body 37 has a tapered portion 3 that comes into contact with this tapered surface 38A.
7A is formed, and the contact body 37 is configured to be positioned extremely accurately on the central axis of the second spindle 24 by the tapered surface 38A and the tapered portion 37A. Further, the contact surface 37B of the contact body 37 that contacts the small diameter portion 27 is formed into a spherical shape with an extremely smooth surface processed with high precision. The spindles 15 and 24 are in rotatable point contact with each other, and this contact point is located on the same axis that is common to the spindles 15 and 24. The bearing 29, the presser ring 35, and the contact body 37 constitute a connecting mechanism 40 that connects both spindles 15 and 24 to each other so as to be relatively rotatable and cannot be separated from each other.

Next, the operation of this embodiment will be explained.

Rotate the knob 19 (thimble 17) in a predetermined direction, in the state shown in FIG. 1, counterclockwise when viewed from the right end. As a result, the first spindle 15
The screwing position of the inner sleeve 8 is shifted to the right, and the first spindle 15 is rotated and moved to the right. When the first spindle 15 rotates, the protruding shaft 22 at the tip of the first spindle 15
The inner race 31 of the bearing 29 fixed to the bearing 29 also moves to the right while rotating. Rolling ball 33 interposed between inner race 31 and outer race 32
is in a state where it is rotatably clamped from both left and right sides in the figure by both holding grooves 31A and 32A, so as the inner race 31 moves to the right, the outer race 32 also moves to the right. Since the second spindle 24 is prevented from rotating by the set screw 9 and the rotation preventing groove 26,
Move to the right while the rotation is stopped. In this way, the first spindle 15 rotates, but the second spindle 24 is not rotated.
This is what is called straight forward movement. The movement of the spindles 15, 24 at this time is performed smoothly by the rolling of the rolling ball 33 between the races 31, 32.

When a gap larger than the dimensions of the object to be measured (not shown) is formed between the anvil 3 and the tip of the second spindle 24, place the object to be measured in this gap and turn the knob 19 in the opposite direction. Rotate in the direction. As a result, the first spindle 15 moves to the left while rotating.

The flat end of the protruding shaft 22 at the tip of the first spindle 15 is in point contact with the apex of the contact surface 37B of the contact body 37, and the contact body 37 is pressed leftward by the protruding shaft 22 and moves. It happens. As a result, the second spindle 24 holding the contact body 37 is also moved to the left, but since the second spindle 24 is prevented from rotating as described above, it does not rotate, that is, it does not move straight. becomes. At this time, the contact body 37 itself, which the tip of the protruding shaft 22 comes into contact with, may be rotated, but the contact body 37 is rotated by the centripetal movement of the tapered surface 38A and the tapered surface 37A within the fitting hole 38. Since it is accurately positioned, in other words, it is positioned so that the central axes of both spindles 15 and 24 are always the central axis, the rotation of the contact body 37 does not adversely affect the measurement accuracy.

When the object to be measured is held between the anvil 3 and the tip of the second spindle 24, the second spindle 24
is stopped, and the dimensions of the object to be measured are displayed on the scales 7 and 21. Note that even if the knob 19 is further rotated after the tip of the second spindle 24 comes into contact with the object to be measured, only the knob 19 will rotate freely since the knob 19 has a built-in ratchet mechanism. ing.

According to this embodiment as described above, there are the following effects.

That is, since the first spindle 15 and the second spindle 24 are connected to each other by a connecting mechanism 40 constituted by a bearing 29 and a contact body 37 so as to be able to freely rotate relative to each other and cannot be separated from each other, the first spindle 15 is connected to a so-called screw. The second spindle 24, which actually holds the object to be measured between the anvil 3 and the anvil 3, can be moved in a straight line, although it is rotated by a feeding method. Therefore, the tip of the second spindle 24 does not come into contact with the object to be measured while rotating, and even when the object to be measured is made of a soft (flexible) material, highly accurate measurement can be performed. can.

Furthermore, the bearing 29 and the contact body 37 are not provided on the outer peripheral sides of both the spindles 15, 24, but are provided on the common axis of both the spindles 15, 24. Therefore, the radial shape is not expanded, the thimble does not have a large diameter, and a micrometer that is small, easy to operate with one hand, and excellent in operability can be obtained. Furthermore, the structures of the bearing 29 and the contact body 37 are extremely simple, and the entire micrometer does not become elongated. Further, when assembling the micrometer, the contact body 37 can be simply inserted into the insertion hole 38, and the contact body 37 does not have to be accurately positioned and fixed to the second spindle 24, so that the assembly work can be easily performed.

Furthermore, the first spindle 15 is brought into contact with the contact surface 37A of the contact body 37, and since this contact surface 37A has a spherical shape with a relatively large arc, the first spindle 15
Even if the spindle 15 is moved back and forth repeatedly, the contact surface 37A or the tip of the stepped protrusion shaft 22 that comes into contact with the contact surface 37A is unlikely to be dented due to wear or the like. Therefore, when the micrometer is used for a long period of time, relative displacement between the two spindles 15 and 24 becomes difficult, and the first spindle 15 can push the second spindle 24 straight, thereby maintaining measurement accuracy. . Furthermore, since it is easy to harden the contact body 37 by hardening or the like,
The contact body 37 can have a structure that does not wear out even when used for a long period of time.

Further, the holding grooves 31A and 32A of both races 31 and 32 of the bearing 29 are both formed as relatively deep grooves, so that the rolling balls 33 can be held from both the left and right sides, in other words, the shafts of the spindles 15 and 24. The first spindle 1
5 can be reliably transmitted to the axial movement of the second spindle 24. That is, even when the spindles 15 and 24 move in the axial direction, the bearing 2
Each of the rolling balls 33 of 9 is structured to be securely held in the respective holding grooves 31A and 32A, and the rolling balls 33 are
3. There is no possibility that the measurement accuracy will be adversely affected due to the movement of the sensor.

On the other hand, in the case of the contact body 37, the contact body 37 is rotatably held within the insertion hole 38 in an extremely accurately positioned state by the tapered portion 37A and the tapered surface 38A, and is held in rotational contact with the spindle 15. However, the contact body 37 is always connected to the second spindle 24
is located on the axis of Therefore, from this point of view as well, both spindles 15 and 24 are not always displaced and cannot be separated from each other, thereby ensuring measurement accuracy.

Further, the contact body 37 has a contact surface 37B, and has a structure in which the top of the contact surface 37B is in rotatable point contact with the protruding shaft 22, and the frictional force accompanying the rotational contact is minimized. Therefore, the bearing 29
Coupled with the fact that the micrometer is a so-called bearing, the first spindle 15 and the second spindle 24 can be brought into very smooth rotational contact, and from this point of view as well, the micrometer can be made with good operability.

In addition, in implementation, the bearing 29 may be a normal angular type radial bearing, but it has a relatively deep groove and is structured to sandwich the rolling balls 33 from both sides of the spindles 15 and 24 in the axial direction. According to the bearing 29 having both races 31 and 32 in which holding grooves 31A and 32A are formed, the rolling ball 33 is reliably held in the forward and backward directions of the spindles 15 and 24.
5 and 24, each rolling ball 33 is in the groove 31.
There is no risk of it shifting from position A or 32A or jumping out.

As described above, according to the present invention, the structure is simple,
In particular, it is possible to provide a linear micrometer that can reduce the thimble diameter, maintain measurement accuracy, and facilitate assembly.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing the overall configuration of an embodiment of a micrometer according to the present invention, and FIG.
The figure is an enlarged sectional view of essential parts of the embodiment. 1...Body frame, 6...Outer sleeve,
8...Inner sleeve, 9...Set screw, 15...
...1st spindle, 17... Thimble, 19...
knob, 22... protruding shaft, 24... second spindle,
25... recess, 26... anti-rotation groove, 29... bearing, 31, 32... race, 33... rolling ball, 3
4... Nut, 35... Presser ring, 37... Contact body, 37A... Taper part, 37B... Contact surface,
38... Fitting hole, 38A... Tapered surface, 40...
Connection mechanism.

Claims (1)

[Claims] 1. A first spindle rotated by the rotation of the thimble is screwed onto the main body frame so as to be movable in the axial direction, and a second spindle is fixed to the main body frame coaxially with the first spindle so as to be able to oscillate in the axial direction. The first spindle is movably supported, and has a stepped protrusion protruding from the first spindle, and the stepped protrusion has an axial direction clamped by the stepped portion and a nut screwed into the small diameter portion of the tip. An angular bearing that supports the load of is fitted, a recess is formed at the end of the second spindle on the first spindle side, and the recess has a conical shape with a top located on the axis of the second spindle. A fitting hole having a tapered surface is provided in succession, and further, the first spindle and the second spindle are connected to each other.
The spindle is held in the insertion hole with a predetermined gap in the circumferential direction, has a tapered part that contacts the tapered surface at one end, and has a relatively large arc that contacts the first spindle at the other end and extends to the edge. A substantially cylindrical contact body each having a spherical contact surface formed therein; and a presser ring that is screwed into the recess of the second spindle and abuts the angular bearing from the opposite side of the contact body; A micrometer characterized in that the spindles are connected via a connecting mechanism that connects spindles so that they can rotate freely and cannot be separated from each other in the axial direction.