JP4749708B2 - Spindle braking device and measuring instrument - Google Patents

Description

  The present invention relates to a spindle braking device and a measuring instrument, for example, a dial gauge and a spindle braking device provided in the dial gauge.

Conventionally, a dial gauge is known as a measuring instrument having a spindle that moves up and down through the main body case, and in order to avoid the probe provided at the tip of the spindle from colliding strongly with the object to be measured, A dial gauge provided with a braking device (spindle braking device) for preventing the fall is known (for example, Patent Document 1).
FIG. 10 is a view showing a braking device 700 of a conventional dial gauge 800.
In FIG. 10, a dial gauge 800 includes a spindle 300 penetrating the main body case 200 so as to be movable up and down, a bushing 212 as a guide means for guiding the upper end side of the spindle 300, and a braking device that brakes the spindle 300. 700.
The spindle 300 is urged downward by urging means (not shown).
The braking device 700 includes a long cylindrical cylinder 610 that is fitted on the upper end side of the bush 212 and a movable member 710 that is slidably provided in the cylinder 610.

The bush 212 is press-fitted to the cylinder 610 so as to maintain airtightness.
On the upper end side of the cylinder 610, a partition body 740 and a cap 760 for defining a valve chamber between the partition body 740 are provided.
The partition body 740 has a through hole 742 that communicates the inside of the cylinder 610 with the valve chamber, and the partition body 740 has a tapered valve seat 741 that increases in diameter at the upper end side opening of the through hole 742. A ball 750 is seated on the valve seat 741, and the through hole 742 is closed.
The cap 760 has a vent hole 761 that allows the valve chamber to communicate with the outside.

  The movable member 710 defines a first partition chamber 616 between the bushing 212 and the cylinder 610, and defines a second partition chamber 617 between the partition 740 and the cylinder 610. The outer diameter of the movable member 710 is slightly smaller than the inner diameter of the cylinder 610, and a predetermined gap exists between the movable member 710 and the inner wall of the cylinder 610. A through hole 711 is formed in the movable member 710. Further, a stop screw 720 and a mounting screw 730 are sequentially screwed onto the upper end of the spindle 300, and the head 731 of the mounting screw 730 engages with the inner wall surface of the through-hole 711 of the movable member 710. The spindle 300 is integrated. The through hole 711 of the movable member 710 is sealed with a cap 712.

  In such a configuration, when the spindle 300 moves to the upper end side, the upper surface of the stop screw 720 pushes up the lower end surface of the movable member 710, so that the movable member 710 rises together with the spindle 720. When the spindle 300 moves to the lower end side, the lower surface of the head 731 of the mounting screw 730 pulls down the inner wall bottom surface of the through hole 711, so that the movable member 710 descends together with the spindle 300.

  The first compartment 616 and the second compartment 617 are substantially airtight chambers except for the gap between the movable member 710 and the inner wall of the cylinder 610. When the movable member 710 descends to the lower end side, the pressure in the first compartment 616 increases and the pressure in the second compartment 617 decreases. As a result, the movable member 710 floats against gravity to some extent in the cylinder 610 (floating structure), and the spindle 300 is braked by the buoyancy acting on the movable member 710.

  Incidentally, the ball 750 seated on the valve seat 741 of the partition body 740 corresponds to a decrease in gravity (in the axial direction) acting on the spindle 300 and the movable member 710 when the dial gauge 800 is tilted sideways. The dial gauge 800 is provided to reduce the braking force by opening the through hole 742 when the dial gauge 800 falls to the side.

Japanese Patent Publication No. 3-70761

As described above, in the braking device 700 shown in FIG. 10, the movable member 710 moves up and down in the cylinder 610 together with the spindle, and the vertical movement of the movable member 710 corresponds to the stop screw 720 according to the vertical movement of the spindle 300. The upper surface pushes up the lower end surface of the movable member 710, and the lower surface of the head 731 of the mounting screw 730 lowers the bottom surface of the inner wall of the through hole 711. That is, the vertical movement of the movable member 710 is performed by a force applied to the lower end portion of the movable member 710.
However, when moving to the upper end side, the movable member 710 is moved by the force applied to the end portion on the opposite side to the moving direction, so that the floating of the movable member 710 is difficult to stabilize. For example, there is a risk that the movable member 710 tilts and the outer surface of the upper end portion of the movable member 710 collides with or is caught by the inner wall of the cylinder 610. As described above, the unstable movement of the movable member 710 causes problems in the operation of the spindle 300 and the durability of the dial gauge 800 is lowered.

  An object of the present invention is to provide a spindle braking device and a measuring instrument that can improve the operability and durability of the spindle.

The spindle braking device of the present invention is a braking device that brakes the moving speed of a spindle that is reciprocally moved in the axial direction while being inserted into a cylindrical bush, and has one end attached to the bush and the spindle. A cylinder having a space in which the cylinder moves reciprocally, a piston that is accommodated in the cylinder so as to be movable in the axial direction, and that divides the cylinder into a first cylinder chamber and a second cylinder chamber; And interlocking means for connecting via a certain clearance with respect to the direction perpendicular to the axis, and a micro flow path provided so as to allow a relatively small amount of fluid to flow through the first cylinder chamber and the second cylinder chamber. The interlocking means is provided at the other end of the spindle with the engagement hole formed inside the piston leaving the side wall portions on both ends of the piston, and is engaged in the engagement hole. And when the spindle moves to one end side, the engaging portion comes into contact with the inner wall on one end side of the engagement hole and the spindle moves to the other end side. The engaging hole and the engaging portion are formed so that the engaging portion contacts the inner wall on the other end side of the engaging hole, and the other end side end surface of the engaging portion is cut toward one end side. A cut groove that is inserted and communicates with the second cylinder chamber and the engagement hole is formed .

According to such a configuration, the piston is movable in the axial direction in the cylinder, and the spindle and the spindle are connected to each other with a certain clearance in the axial direction. Is moved, the engaging portion provided at the other end of the spindle comes into contact with the inner wall on the other end side of the engaging hole. And a piston is moved to the other end side by being pushed by the engaging part contact | abutted to the other end side inner wall. On the other hand, when the spindle moves to one end side, the engaging portion comes into contact with the inner wall on one end side of the engaging hole. And a piston is moved to the one end side by being pulled by the engaging part contact | abutted to the one end surface side wall part.
Thus, as the spindle moves, the piston is moved by applying a force to the moving direction side end, so that the fluctuation of the floating of the piston is reduced and the outer surface of the piston is caught on the inner wall of the cylinder, etc. Fear is reduced. As a result, the operability of the spindle is improved, and the durability of the braking device is improved.

  The piston is movable in the axial direction in the cylinder and partitions the cylinder into a first cylinder chamber and a second cylinder chamber. Therefore, a gap for communicating the first cylinder chamber and the second cylinder chamber exists between the outer surface of the piston and the inner wall of the cylinder, and the fluid in the cylinder passes through the gap and passes through the first cylinder chamber and the second cylinder chamber. It can move between two cylinder chambers. From this, the fluid in the cylinder can move between the first cylinder chamber and the second cylinder chamber in accordance with the movement of the piston and the spindle, so that the spindle can move in a braked state. .

  In the brake device for a spindle according to the present invention, the engagement hole includes a hollow chamber formed in the piston and a first communication passage formed in the side wall portion of the other end surface of the piston and communicating the hollow chamber and the first cylinder chamber. The engagement portion is housed in the hollow chamber, and has a valve head whose outer dimension is smaller than the inner shape of the hollow chamber and larger than the first communication path, and is inserted into the first communication path. And a valve stem that connects the spindle, and the valve stem has a length that secures a predetermined clearance between the spindle and the piston in a state where the valve head is in contact with the inner wall on the other end side of the hollow chamber. It is preferable.

  According to such a configuration, the valve head housed in the hollow chamber has a smaller dimensional outline than the inner shape of the hollow chamber, and the valve stem connects the valve head and the spindle, so the interlocking means is relatively simple. With this configuration, the spindle and the piston can be coupled to each other with a certain clearance in the axial direction and the direction orthogonal to the axis.

  The valve stem has a length that ensures a predetermined clearance between the spindle and the piston in a state where the valve head is in contact with the inner wall at the other end of the hollow chamber. However, the spindle does not contact the outer surface of one end of the piston. That is, when the piston moves, the piston receives a force from the valve head to one of the inner walls at both ends of the hollow chamber, and does not receive a moving force from the other part. This does not prevent the piston from floating.

The braking device of the spindle of the present invention, closed a main channel in which the fluid is provided to be distributed communicating the first cylinder chamber and a second cylinder chamber, the main flow path when the spindles are moved into the one end And an opening / closing means for opening the main flow path when the spindle moves to the other end side, and the engagement portion is formed on the side wall portion on the one end surface side of the piston and communicates with the hollow chamber and the second cylinder chamber. A second communication passage is provided, the main flow path is constituted by a hollow chamber and first and second communication passages, and the opening / closing means is provided in a valve seat provided in the engagement hole and in the engagement portion. At the same time, it is preferable that the valve head be configured to include a valve head that is in contact with and separated from the valve seat from the opposite side of the spindle with the valve seat interposed therebetween.

In such a configuration, when the spindle moves to the other end side, the movement of the spindle is transmitted to the valve head by the valve rod, and the valve head is separated from the valve seat. Then, since the main flow path is opened, the second cylinder chamber communicates with the first cylinder chamber by the main flow path in addition to the fine flow path. Then, fluid flows out from the second cylinder chamber from the fine flow path and the main flow path. As a result, since the positive pressure in the second cylinder chamber is suppressed, the braking effect is reduced when the spindle moves toward the other end side.
When the spindle moves to one end side, the movement of the spindle is transmitted to the valve head by the valve rod, and the valve head moves to the one end side together with the spindle and comes into contact with the valve seat. Then, since the main flow path is closed, a small amount of fluid flows into the second cylinder chamber from only the fine flow path. Then, a negative pressure is generated in the second cylinder chamber by moving the piston to one end side. As a result, when the spindle moves toward one end, a large braking effect can be obtained by the internal pressure (negative pressure) in the second cylinder chamber.

That is, a braking effect can be obtained only when the spindle moves to one end side, and no braking effect can be generated when the spindle moves to the other end side. Thus, for example, when a measuring element is provided at one end of the spindle, it is possible to prevent inconvenience such as the measuring element colliding with an object to be measured when the spindle suddenly moves (for example, drops) to one end side, Since the spindle can be easily moved (for example, lifted) to the other end side, the operability of the spindle is improved.
Moreover, according to such a structure, since the braking effect is acquired by the internal pressure of the second cylinder chamber, the first cylinder chamber may be opened. As a result, the step of sealing the first cylinder chamber is not necessary as compared with the conventional case.
Further, since the spindle and the valve head are integrally moved by the valve rod, the opening / closing operation of the opening / closing means is interlocked with the movement of the spindle.

When the spindle is moved to one end side, the valve head is seated from the opposite side of the spindle with the valve seat in between, and the valve head is pulled by the spindle via the valve stem. When moving to one end side, the valve head is more strongly seated on the valve seat and the main flow path is more reliably closed. That is, when the spindle moves to one end side, the main flow path is completely closed, and the airtightness (excluding the fine flow path) of the second cylinder chamber is enhanced. Thus, when the spindle moves to the lower end side, the braking force can be reliably applied to the spindle.
Further, when the valve head is moved to one end side along with the spindle via the valve stem, the piston is also pulled together with the spindle toward the one end side by the contact between the valve seat and the valve head. Accordingly, it is not necessary to separately provide a means for engaging the spindle and the piston, so that a simple configuration can be achieved.

In the spindle brake device according to the present invention, the elastic member is disposed on the valve seat and is sandwiched between the valve seat and the valve head when the valve head comes into contact with the valve seat and seals between the valve seat and the valve head. Are preferably provided.
According to this configuration, when the valve head is seated on the valve seat, the clearance between the valve seat and the valve head is completely sealed by the elastic deformation of the elastic member, and the second cylinder chamber (excluding the micro flow path is removed). ) Airtightness is improved.

The measuring instrument of the present invention includes a main body case, a spindle that passes through the main body case and is provided so as to be movable in the axial direction, a bush that is provided in the main body case and guides the spindle, and a display means for displaying the amount of displacement of the spindle. And a spindle braking device according to any one of claims 1 to 4.
According to this structure, there can exist an effect similar to the invention as described above.
The display means for displaying the displacement of the spindle may display the detected value by detecting the amount of displacement of the spindle with an encoder (for example, photoelectric type, capacitance type, magnetic type encoder), for example. Alternatively, the displacement amount of the spindle may be enlarged and displayed by a gear mechanism.

The measuring instrument of the present invention includes a main body case, a spindle that passes through the main body case and is provided so as to be movable in the axial direction, a bush that is provided in the main body case and guides the spindle, and a display means for displaying the amount of displacement of the spindle. And a spindle brake device according to claim 3 or 4, and a lifter portion provided with one end attached to the valve head and the other end protruding from the other end side opening of the cylinder. It is characterized by that.
According to such a configuration, the same operational effects as the above-described invention can be achieved. Furthermore, for example, when measuring the depth of a hole or the like, the lower end side of the spindle cannot be held by hand, but a lifter unit is provided as a means for lifting the spindle to the upper end side of the spindle. An operation of lifting the spindle can be performed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of each embodiment, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.
<First Embodiment>
1 to 4 show a first embodiment of the present invention. 1 is a front view showing the measuring instrument of the first embodiment, FIG. 2 is a cross-sectional view showing the internal structure of the measuring instrument, and FIG. 3 is a braking device when the spindle moves to the upper end side (the other end side). FIG. 4 is a cross-sectional view showing the braking device when the spindle moves to the lower end side (one end side).
As shown in these drawings, the measuring instrument of the first embodiment is a dial gauge (indicator) 100, and a main body case 200 having a storage space inside, and a reciprocating movement in the axial direction through the main body case 200. A possible spindle 300, a biasing means 400 (see FIG. 2) for biasing the spindle 300 toward the lower end in the axial direction, a displacement detection means 500 for detecting the amount of displacement of the spindle 300, and a lowering of the spindle 300 And a braking device 600 that brakes the speed.

As shown in FIG. 1, the main body case 200 includes a guide unit 210 that guides the moving direction of the spindle 300 and a display unit 220 as an output unit that displays the displacement amount of the spindle 300.
As shown in FIG. 2, the guide unit 210 includes a stem 211 that guides the lower end side of the spindle 300 and a bush 212 that guides the upper end side of the spindle 300. The stem 211 and the bush 212 are cylindrical members attached to the side walls of the main body case 200 with their axes aligned at the opposing positions, and the spindle 300 is slidably fitted into the cylindrical holes of the stem 211 and the bush 212. Has been.

  The bush 212 is a short cylindrical member, and has a flange portion 213 that protrudes in a flange shape from the outer peripheral surface at substantially the center in the axial direction. As shown in FIG. 3, a lower end side large diameter portion 217 is formed on the outer peripheral surface of the bush 212. The lower end side large diameter portion 217 increases in diameter with the reduced diameter portion 216 between the flange portion 213 and the lower end side. Further, on the outer periphery of the bush 212, an upper-end-side large-diameter portion 215 that is enlarged in diameter with the reduced-diameter portion 214 interposed between the upper-end side and the flange portion 213 is formed. The bush 212 is attached to the main body case 200 by pressing the lower end side (the reduced diameter portion 216 and the lower end side large diameter portion 217) of the flange portion 213 into the side wall of the main body case 200.

The spindle 300 includes a measuring element 310 having a predetermined rigidity at the lower end, and a female screw portion 320 at the upper end.
The biasing means 400 includes a guide rod 410 fixed in parallel with the spindle 300 in the housing space of the main body case 200, one end slidable along the guide rod 410, and the other end fixed to the spindle 300. A guide piece 420 and a coil spring 440 that is provided by being extrapolated to the guide rod 410 and biases one end of the guide piece 420 toward the lower end side.

  The displacement detection unit 500 includes an index scale 510 provided in parallel to the spindle 300 via an attachment member 520, and a detection unit 530 that is fixed to the main body case 200 and detects the amount of displacement of the index scale 510. The detection value detected by the detection unit 530 is displayed on the display unit 220.

  As shown in FIGS. 3 and 4, the braking device 600 is accommodated in a cylinder 610 having a space where the lower end is attached to the bush 212 and the spindle 300 reciprocates, and the cylinder 610 is movable in the axial direction. A piston 620 that divides the inside of the cylinder into a first cylinder chamber 611 and a second cylinder chamber 612; an engagement portion 630 that is provided at the upper end of the spindle 300 and interlocks the piston 620 in accordance with the movement of the spindle 300; A relatively small amount of fluid flows through the main flow path 640 provided to allow fluid to flow through the first cylinder chamber 611 and the second cylinder chamber 612, and through the first cylinder chamber 611 and the second cylinder chamber 612. The microchannel 650 is provided so as to be possible.

  The cylinder 610 has an inner wall that is smoothly finished with high accuracy, and a lower end thereof is screwed into the bush 212. That is, the push male screw formed in the upper end side large diameter portion 215 of the bush 212 and the female screw formed in the lower end side opening of the cylinder 610 are screwed together. A cylinder cap 613 is fitted to the upper end of the cylinder 610, and the upper end side opening of the cylinder 610 is sealed in a liquid-tight manner.

The piston 620 defines a first cylinder chamber 611 between the bushing 212 and the spindle 300 on the lower end side, and forms a second cylinder chamber 612 between the piston cap 613 and the cylinder cap 613 on the upper end side of the piston 620. To do.
The piston 620 is a metal member, and includes a piston main body 621 having an outer diameter that is substantially equal to the inner diameter of the cylinder 610, and a lid 622 provided at the upper end of the piston main body 621. The piston body 621 has a cylindrical hollow chamber 623 formed therein as an engagement hole, and a first communication that is formed in the axial direction in the side wall of the lower end surface to communicate the hollow chamber 623 and the first cylinder chamber 611. The passage 624 and the valve seat 625 provided on the lower inner wall of the hollow chamber 623 are configured. The lid body 622 is fitted over the opening of the hollow chamber 623 and is penetrated in the axial direction at the center to form a second communication passage 626 that allows the hollow chamber 623 and the second cylinder chamber 612 to communicate with each other.

The engaging portion 630 includes a valve head 631 accommodated in the hollow chamber 623 and a valve rod 632 that connects the valve head 631 and the upper end of the spindle 300 while being inserted through the first communication passage 624 in the axial direction. A dimension clearance 633 is provided between the inner wall of the hollow chamber 623 and the valve head 631 in the direction perpendicular to the axis.
The valve head 631 has a cylindrical shape whose outer dimension is smaller than the inner shape of the hollow chamber 623 and larger than the first and second communication passages 624 and 626, and the upper end surface is cut toward the lower end side. A cross-shaped cut groove 634 is formed. The cut groove 634 has a tip extending to the outer peripheral edge with the center of the axis as an intersection of the cross, and the tip is formed by cutting a side surface. Since the intersection of the notch groove 634 faces the second communication passage 626 of the piston 620, the second cylinder chamber 612 and the second cylinder chamber 612 are hollow even when the upper end surface of the valve head 631 is in contact with the inner wall of the upper end side of the hollow chamber 623. The chamber 623 is in communication.

The valve stem 632 has an axial dimension having a predetermined clearance 635 secured between the spindle 300 and the piston 620 in a state where the upper end surface of the valve head 631 is in contact with the inner wall on the upper end side of the hollow chamber 623. The valve stem 632 is formed with a male threaded portion carved at the lower end, and the male threaded portion is screwed into the female threaded portion of the spindle 300 so that the engaging portion 630 is fixed to the upper end of the spindle 300. Is done. As a result, the engaging portion 630 moves integrally with the spindle 300 in the cylinder 610.
The dimension clearance 633 is ensured because the valve head 631 has a smaller outer dimension than the hollow chamber 623 as described above.

The main flow path 640 includes a second communication path 626 of the piston 620, a cut groove 634 of the valve head 631, a hollow chamber 623, and a first communication path 624 from the second cylinder chamber 612 side.
The microchannel 650 is configured by a gap between the inner wall of the cylinder 610 and the outer peripheral surface of the piston 620.

  The piston 620 and the engaging portion 630 constitute an interlocking means 660 and an opening / closing means 670 by mutual configuration. The interlocking means 660 couples the piston 620 to the spindle 300 via the dimension clearance 633 in the axial direction and the orthogonal direction of the spindle 300, and reciprocates the piston 620 in the axial direction in accordance with the movement of the spindle 300. Let The opening / closing means 670 opens / closes the main flow path 640 according to the reciprocation of the spindle 300 in the axial direction.

The interlocking unit 660 includes a hollow chamber 623 and a first communication path 624 of the piston 620 and an engaging portion 630 having a valve head 631 accommodated in the hollow chamber 623.
A dimensional clearance 633 is secured between the inner wall of the hollow chamber 623 and the valve head 631, and the outer shape of the valve head 631 is larger than those of the first and second communication passages 624, 626. It is possible to move in the axial direction and in the direction perpendicular to the axis with respect to the piston 620 in the state of being accommodated in 623. That is, with such a configuration, the piston 620 is connected to the spindle 300 so as to be movable in the axial direction and the direction orthogonal to the axis.
In addition, a dimensional clearance 633 is secured between the inner wall of the hollow chamber 623 and the valve head 631, and the upper end surface of the valve head 631 contacts the upper inner wall of the hollow chamber 623 depending on the axial dimension of the valve rod 632. Since the predetermined clearance 635 is ensured between the spindle 300 and the piston 620 in the contact state, the interlocking unit 660 interlocks the piston 620 in accordance with the reciprocating movement of the spindle 300 in the axial direction.

The opening / closing means 670 includes a valve head 631 of the engaging portion 630 and a valve seat 625 provided in the hollow chamber 623 of the piston 620.
As described above, the engaging portion 630 moves integrally with the spindle 300, and the valve head 631 moves in the axial direction and the axis orthogonal direction with respect to the piston 620 while being accommodated in the hollow chamber 623. Can do. By the reciprocating movement of the valve head 631 in the axial direction, the lower end surface of the valve head 631 is separated and abutted against the valve seat 625 of the hollow chamber 623.

The operation of the first embodiment having such a configuration will be described. First, a case where the spindle 300 moves to the upper end side as shown in FIG. 3 will be described.
When the spindle 300 moves to the upper end side, first, in the opening / closing means 670, the valve head 631 also moves to the upper end side with respect to the hollow chamber 623, so that the lower end surface of the valve head 631 is separated from the valve seat 625. At this time, the hollow chamber 623 and the first communication passage 624 communicate with each other, and the cut groove 634 of the valve head 631 is formed even in a state where the upper end surface of the valve head 631 is in contact with the upper end side inner wall of the hollow chamber 623. Thus, the hollow chamber 623 and the second communication passage 626 communicate with each other. That is, when the spindle 300 moves to the upper end side, the main channel 640 is opened by the opening / closing means 670.
At the same time, in the interlocking means 660, the upper end surface of the valve head 631 comes into contact with the upper end side inner wall of the hollow chamber 623. At this time, the valve head 631 is not in contact with the inner wall at the lower end side of the hollow chamber 623 due to the dimension clearance 633. Further, the upper end of the spindle 300 is not in contact with the outer wall on the lower end side of the piston 620 due to the predetermined clearance 635. The piston 620 is moved to the upper end side together with the spindle 300 by being pushed up by the valve head 631 in contact with the inner wall on the upper end side of the hollow chamber 623.

At this time, a positive pressure is generated in the second cylinder chamber 612 (a negative pressure is generated in the first cylinder chamber 611). At this time, since the first cylinder chamber 611 and the second cylinder chamber 612 are communicated with each other by the main flow path 640 in addition to the fine flow path 650, the second cylinder chamber 612 passes through the fine flow path 650 and the main flow path 640. Air (fluid) flows into the first cylinder chamber 611. Then, generation of positive pressure in the second cylinder chamber 612 (and generation of negative pressure in the first cylinder chamber 611) is suppressed to a predetermined level or less.
Thereby, the piston 620 together with the spindle 300 moves in the cylinder 610 to the upper end side without receiving a large resistance.

Next, the case where the spindle 300 is lowered as shown in FIG. 4 will be described.
For example, when the spindle 300 moves to the lower end side due to the biasing force of the coil spring 440 (see FIG. 2) and the weight of the spindle 300, first, the valve head 631 also moves to the lower end side with respect to the hollow chamber 623 in the opening / closing means 670. The lower end surface of the head 631 contacts the valve seat 625. When the valve head 631 contacts the valve seat 625, the hollow chamber 623 and the first communication path 624 are blocked. That is, when the spindle 300 moves to the lower end side, the main channel 640 is closed by the opening / closing means 670.
At the same time, the lower end surface of the valve head 631 contacts the valve seat 625 of the hollow chamber 623 in the interlocking means 660. At this time, the valve head 631 is not in contact with the inner wall on the upper end side of the hollow chamber 623 due to the dimensional clearance 633. The piston 620 is moved to the lower end side together with the spindle 300 by being pulled down by the valve head 631 in contact with the valve seat 625 of the hollow chamber 623.

At this time, a negative pressure is generated in the second cylinder chamber 612 (a positive pressure is generated in the first cylinder chamber 611).
Since the first cylinder chamber 611 and the second cylinder chamber 612 are communicated with each other through the micro flow path 650, gas (fluid) flows from the first cylinder chamber 611 into the second cylinder chamber 612 through the micro flow path 650. .
Here, since the flow rate through the micro flow path 650 is very small, the negative pressure in the second cylinder chamber 612 is buffered little by little. As a result, the descending speed of the piston 620 is decelerated by the negative pressure in the second cylinder chamber 612. (Braking). The descending speed of the spindle 620 is braked by braking the descending speed of the piston 620.

According to the first embodiment, the following effects can be expected.
(1) The piston 620 can move in the axial direction in the cylinder 610, and the piston 620 and the spindle 300 are connected to each other via the dimension clearance 633 in the axial direction. The valve head 631 of the engaging portion 630 comes into contact with the inner wall on the upper end side of the hollow chamber 623. The piston 300 is moved up to the upper end side by being pushed up by the valve head 631 in contact with the upper end side inner wall. On the other hand, when the spindle 300 moves to the lower end side, the valve head 631 contacts the lower end side inner wall of the hollow chamber 623. The piston 620 is moved to the lower end side by being pulled down by the valve head 631 in contact with the lower end side wall portion.
As described above, the piston 620 is moved by applying a force to the moving direction side end in accordance with the movement of the spindle 300, so that the floating fluctuation of the piston 620 is reduced, and the outer surface of the upper end of the piston 620 is reduced. Is less likely to be caught on the inner wall of the cylinder 610. Thus, the operability of the spindle 300 is improved and the durability of the braking device is improved.

(2) The piston 620 can move in the axial direction in the cylinder 610 and partitions the cylinder 610 into a first cylinder chamber 611 and a second cylinder chamber 612. From this, there is a gap for communicating the first cylinder chamber 611 and the second cylinder chamber 612 between the outer surface of the piston 620 and the inner wall of the cylinder 610, and the air in the cylinder 610 passes through this gap, The first cylinder chamber 611 and the second cylinder chamber 612 can be moved. From this, the air in the cylinder 610 can move in the first cylinder chamber 611 and the second cylinder chamber 612 in accordance with the movement of the piston 620 and the spindle 300, so that the spindle 300 is in a braked state. You can move with.

(3) The valve head 631 accommodated in the hollow chamber 623 has a smaller dimensional outline than the inner shape of the hollow chamber 623, and the valve stem 632 connects the valve head 631 and the spindle 300. With a simple configuration, the spindle 300 and the piston 620 can be coupled to each other in the axial direction and the direction perpendicular to the axis via the dimension clearance 633.
(4) The valve stem 632 has a length that ensures a predetermined clearance 635 between the spindle 300 and the piston 620 in a state where the valve head 631 is in contact with the inner wall on the upper end side of the hollow chamber 623. The spindle 300 does not contact the outer surface of the lower end side of the piston 620 no matter which direction the 300 moves. That is, when the piston 620 moves, the piston 620 is applied with a force from the valve head 631 to either one of the inner walls at both ends of the hollow chamber 623 and is not applied with a force for movement to the other part. . Thus, the floating of the piston 620 is not hindered.

(5) When the spindle 300 moves to the upper end side, the main flow path 640 is opened, and when the spindle 300 moves to the lower end side, the main flow path 640 is closed by the valve head 631. Therefore, a braking effect can be obtained only when the spindle 300 moves to the lower end side, and no braking effect can be generated when the spindle 300 moves to the upper end side. As a result, it is possible to prevent inconveniences such as the spindle 300 suddenly dropping to the lower end side and causing the probe 310 to collide with the object to be measured (not shown), while the spindle 300 can be easily lifted to the upper end side.

(6) Since only the second cylinder chamber 612 needs to be substantially liquid-tightly partitioned by the piston 620, the first cylinder chamber 611 may be opened. Therefore, the process of sealing the first cylinder chamber 611 is not necessary as compared with the conventional case. As a result, the assembly process can be simplified and the production efficiency can be improved.
(7) When the valve head 631 in contact with the valve seat 625 moves to the lower end side together with the spindle 300 via the valve rod 632, the main flow path 640 is strongly blocked by the contact between the valve head 631 and the valve seat 625. Therefore, when the spindle 300 moves to the lower end side, the main flow path 640 is completely closed, and the airtightness (excluding the fine flow path 650) of the second cylinder chamber 612 is improved. Thereby, when the spindle 300 moves to the lower end side, the braking force can be reliably applied to the spindle 300.

(8) The valve head 631 is moved to the lower end side together with the spindle 300 via the valve rod 632. At this time, due to the contact between the valve head 631 and the valve seat 625, the piston 620 is also pulled down to the lower end side together with the spindle 300. Therefore, it is not necessary to separately provide means for engaging the spindle 300 and the piston 620, so that the configuration can be simplified.
(9) Since the spindle 300 and the valve head 631 move integrally by the valve rod 632, the opening / closing operation of the opening / closing means 670 can be interlocked with the movement of the spindle 300.

<Modification of First Embodiment>
The dial gauge 100 of the first embodiment may have a configuration as shown in FIG.
Although the dial gauge 100 shown in FIG. 5 is the same as that of 1st Embodiment, it has the characteristics in the point to which the lifter part 900 is attached.
The lifter portion 900 includes a shaft body 910 and an outer cylinder portion 920. The shaft body 910 is inserted into the cylinder 610 from an opening formed at the upper end of the cylinder 610, and a lower end is screwed into the valve head 631, and an upper end protrudes outside the cylinder 610.
The outer cylinder portion 920 is attached to the upper end of the shaft body 910 and covers the cylinder 610 so as to cover the outside of the cylinder 610. Further, the cylinder cap 613 is removed.

In such a configuration, when the outer cylinder portion 920 of the lifter portion 900 is lifted to the upper end side, the valve head 631 is lifted to the upper end side together with the shaft body 910. Further, when the valve stem 632 is lifted together with the valve head 631, the spindle 300 is pulled up via the valve stem 632, and the piston 620 is pushed up by the upper end of the spindle 300.
On the other hand, when the spindle 300 is biased toward the lower end side by the coil spring 440 (see FIG. 2), the operation when the spindle 300 moves toward the lower end side is the same as that of the first embodiment.

  According to such a configuration, the lifter unit 900 can perform an operation of pulling up the spindle 300 to the upper end side. For example, even when it is impossible to hold the lower end side of the spindle 300 by hand when measuring the depth of the hole, the spindle 300 can be pulled up to the upper end side by the lifter unit 900. Further, when the lifter unit 900 is provided, it is only necessary to remove the cylinder cap 613 from the configuration of the first embodiment and attach the lifter unit 900 to the valve head 631. Therefore, the attachment of the lifter unit 900 is very simple.

The gap D between the outer cylinder part 920 and the cylinder 610 of the lifter part 900 is not particularly limited, but the gap D between the outer cylinder part 920 and the cylinder 610 is preferably narrowed. If the gap D between the outer cylinder portion 920 and the cylinder 610 is small, the airtightness of the second cylinder chamber 612 is increased, and the braking effect of the spindle 300 is obtained by the second cylinder chamber 612.
In attaching the lifter unit 900, for example, as shown in FIG. 6, the lifter unit 900 may be provided after the cylinder 610 is removed. In addition, the shape of the lifter unit 900 is not particularly limited, and the lifter unit 900 may include only the shaft body 910 without the outer cylinder unit 920.

Second Embodiment
7 and 8 show a second embodiment of the present invention. FIG. 7 is a sectional view showing a braking device when the spindle moves to the upper end side (the other end side) in the measuring instrument of the second embodiment, and FIG. 8 shows the spindle moving to the lower end side (the other end side). It is sectional drawing which shows a braking device at the time.
The measuring instrument of 2nd Embodiment is the dial gauge 100 similarly to 1st Embodiment. As shown in FIGS. 7 and 8, the braking device 690 of the second embodiment is different from the braking device 690 of the first embodiment in that the second communication passage 626 is not formed in the lid 622 of the piston 620. The point that the notch groove is not formed in the valve head 631 of the engaging portion 630, the point that the main flow path is not provided from these two points, and the point that the opening and closing means are not configured because the main flow path is not provided Furthermore, a difference is that a cylinder opening / closing means 730 is provided at the upper end of the cylinder 610 instead of the cylinder cap. That is, the first cylinder chamber 611 and the second cylinder chamber 612 are communicated only by the fine flow path 650.

The cylinder opening / closing means 730 adjusts the braking force performed by the braking device 690 by communicating the second cylinder chamber 612 with the outside according to the direction of the dial gauge 100. The cylinder opening / closing means 730 is provided with a partition body 740 and a cap 760 for defining a valve chamber between the partition body 740.
The partition body 740 has a through hole 742 that communicates the inside of the cylinder 610 with the valve chamber, and the partition body 740 has a tapered valve seat 741 that increases in diameter at the upper end side opening of the through hole 742. A ball 750 is seated on the valve seat 741, and the through hole 742 is closed. The cap 760 has a vent hole 761 that allows the valve chamber to communicate with the outside.

As shown in FIGS. 7 and 8, when the dial gauge 100 is tilted sideways, the gravity acting in the axial direction with respect to the spindle 300 decreases, and the ball of the cylinder opening / closing means 730 moves inside the valve seat 741 according to the gravity. Since it rolls to the side, the through hole 742 is opened. Then, the second cylinder chamber 612 communicates with the outside through the through hole 742 and the vent hole 761.
As described above, when the measurement is performed with the dial gauge 100 tilted sideways, when the spindle 300 moves to the upper end side, the air in the second cylinder chamber 612 passes through the opened through hole 742 and vent hole 761. Therefore, an increase in pressure in the second cylinder chamber 612 can be suppressed.

According to the second embodiment, in addition to the effects expected from the first embodiment, the following effects can be expected.
(10) When measurement is performed while the dial gauge 100 is tilted sideways, the cylinder opening / closing means 730 opens the through hole 742, so that the first cylinder chamber 611 communicates with the outside. From this, since the increase in the pressure in the second cylinder chamber 612 can be suppressed, the spindle 300 can be moved smoothly. That is, as the gravity acting on the spindle 300 and the piston 620 decreases, the through hole 742 can be opened to reduce the braking force on the spindle 300.

<Modification>
It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
As shown in FIG. 9, an elastic O-ring 627 may be disposed along the valve seat 741 on the inner wall on the lower end side of the hollow chamber 623. According to such a configuration, when the spindle 300 moves to the lower end side, the lower end surface of the valve head 631 and the valve seat 625 sandwich the O-ring 627, so that the main flow path 640 can be sealed more reliably. , Air leakage can be reduced. Thereby, the airtightness of the second cylinder chamber 612 (excluding the micro flow path 650) can be improved.

Moreover, as shown in FIG. 9, the taper part 628 which spreads outside as it goes to a lower end in the 1st communicating path 624 of the piston 620 may be formed. According to such a configuration, the lower end side cross-sectional area of the first communication path 624 is increased, so that air easily passes through the first communication path 624.
The cylinder 610 only needs to contain air, but the cylinder 610 may be filled with a fluid such as oil (for example, a viscous fluid).
The material of the piston 620 is not limited to metal, and, for example, plastic that is highly slidable and lightweight may be used.

The main flow path 640 and the fine flow path 650 may be formed anywhere.
Although the micro flow path 650 is configured by the gap between the inner wall of the cylinder 610 and the outer peripheral surface of the piston 620, a fine hole penetrating the piston 620 may be formed as the micro flow path 650. Alternatively, the micro flow path 650 may be configured by several grooves formed on the outer peripheral surface of the piston 620 along the axial direction.
Furthermore, a flow path (for example, a tube or the like) that connects the first cylinder chamber 611 and the second cylinder chamber 612 may be provided outside the cylinder 610. A check valve may be provided in the main channel.
Alternatively, the fine flow path 650 may be secured by leaving a gap in the fine flow path 650 when the valve head 631 contacts the valve seat 625.
The area ratio between the fine flow path 650 and the main flow path 640 is not particularly limited, but it is exemplified that the main flow path 640 is made larger.

  The present invention can be used as a brake device for a spindle in a measuring instrument having a spindle such as a dial gauge.

The front view which shows the dial gauge concerning 1st Embodiment of this invention. The figure which shows the internal structure of a dial gauge in embodiment same as the above. Sectional drawing which shows the brake device of the spindle concerning embodiment same as the above. Sectional drawing which shows the brake device of the spindle concerning embodiment same as the above. Sectional drawing which shows the modification of the brake device of the spindle concerning embodiment same as the above. Sectional drawing which shows the modification of the brake device of the spindle concerning embodiment same as the above. Sectional drawing which shows the brake device of the spindle concerning 2nd Embodiment of this invention. Sectional drawing which shows the brake device of the spindle concerning embodiment same as the above. Sectional drawing which shows the modification of the brake device of the spindle concerning embodiment of this invention. Sectional drawing which shows the brake device of the conventional spindle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Dial gauge, 200 ... Main body case, 212 ... Bush, 220 ... Display part, 300 ... Spindle, 310 ... Measuring element, 600, 690 ... Braking device, 610 ... Cylinder, 611 ... 1st cylinder chamber, 612 ... 2nd Cylinder chamber, 620 ... Piston, 623 ... Hollow chamber, 624 ... Communication passage, 625 ... Valve seat, 626 ... Communication passage, 627 ... Ring, 630 ... Engagement part, 631 ... Valve head, 632 ... Valve rod, 633 ... Dimensions Clearance, 635 ... Predetermined clearance, 640 ... Main flow path, 650 ... Fine flow path, 660 ... Interlocking means, 670 ... Opening / closing means

Claims (6)

A braking device that brakes a moving speed of a spindle that is reciprocally movable in an axial direction in a state of being inserted into a cylindrical bush,
A cylinder having one end attached to the bush and a space in which the spindle reciprocates;
A piston which is accommodated in the cylinder so as to be movable in the axial direction and divides the cylinder into a first cylinder chamber and a second cylinder chamber;
Interlocking means for connecting the piston to the spindle via an axial direction and a direction orthogonal to the axis through a certain clearance ;
A microchannel provided in a manner that allows a relatively small amount of fluid to flow through the first cylinder chamber and the second cylinder chamber ;
The interlocking means includes an engagement hole formed in the piston leaving the side wall portions on both ends of the piston, and an engagement portion provided in the other end of the spindle and engaged and housed in the engagement hole. When the spindle moves to one end side, the engaging portion abuts against the inner wall on one end side of the engaging hole, and when the spindle moves to the other end side, The engagement hole and the engagement portion are formed such that the engagement portion contacts the inner wall on the other end side of the engagement hole ,
The end surface on the other end side of the engagement portion is formed with a notch groove that is cut toward one end side and communicates the second cylinder chamber and the engagement hole . Braking device. The spindle braking device according to claim 1,
The engagement hole includes a hollow chamber formed in the piston, and a first communication passage formed in the side wall portion of the other end surface of the piston and communicating the hollow chamber and the first cylinder chamber.
The engagement portion is housed in the hollow chamber, and has a valve head whose outer dimension is smaller than the inner shape of the hollow chamber and larger than the first communication path, and is inserted through the first communication path. And comprising a valve stem connecting the valve head and the spindle,
The valve stem has a length that secures a predetermined clearance between the spindle and the piston in a state where the valve head is in contact with the inner wall on the other end side of the hollow chamber. Braking device. The spindle control device according to claim 2,
A main channel provided in fluid communication with the first cylinder chamber and the second cylinder chamber ;
And closing the main flow path in front Symbol spindle is moved to one end side, and a closing means for opening the main flow path when the spindle moves to the other end side,
The engaging portion is provided with a second communication passage formed on the side wall portion of the one end surface of the piston and communicating the hollow chamber with the second cylinder,
The main flow path is composed of the hollow chamber and the first and second communication paths,
The opening / closing means includes a valve seat provided in the engagement hole, a valve head provided in the engagement portion, and contacting / separating the valve seat from the opposite side of the spindle with the valve seat interposed therebetween. A brake device for a spindle, comprising: The spindle braking device according to claim 3,
An elastic member disposed on the valve seat and sandwiched between the valve seat and the valve head when the valve head contacts the valve seat and sealing between the valve seat and the valve head; A brake device for a spindle, comprising: A body case,
A spindle provided through the body case so as to be movable in the axial direction;
A bush provided in the main body case for guiding the spindle;
Display means for displaying the displacement of the spindle;
A measuring instrument comprising: the spindle braking device according to claim 1. A body case,
A spindle provided through the body case so as to be movable in the axial direction;
A bush provided in the main body case for guiding the spindle;
Display means for displaying the displacement of the spindle;
A brake device for a spindle according to claim 3 or 4,
And a lifter portion provided with one end attached to the valve head and the other end protruding from the opening on the other end side of the cylinder.

Images