JPS6221925Y2 - - Google Patents

Description

[Detailed description of the invention] This invention includes a fixed scale fixed to a frame body, a movable scale fixed to a spindle, a light emitting element and a light receiving element facing each other with the pair of scales in between, and the amount of movement of the spindle. Regarding digital dial gauges, which are equipped with an air damper mechanism to alleviate the problem and electrically detect the amount of spindle movement, they are used in machine tools, automatic sorting machines, etc. when the gauge head and frame are horizontal or when the gauge head is on the frame. This invention relates to a digital dial gauge equipped with a control valve that eliminates the effect of an air damper mechanism, increases the protrusion speed of the spindle, and improves followability to the workpiece when it is mounted higher up, for example, upside down. .

A conventional digital dial gauge will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of main parts of a conventional digital dial gauge, and FIG. 2 is a sectional view taken along the line -- in FIG. 1.

In FIGS. 1 and 2, reference numeral 1 denotes a frame made of a metal material such as aluminum or brass, and a pair of bearings made of an upper bush 2 and a stem 3 are provided at opposing positions of the frame 1. A spindle 4 is supported by the upper bush 2 and the stem 3 and is slidable in the axial direction (in the vertical direction in the drawing) with respect to the frame 1, and a measuring element 5 is screwed to the lower end. 6 is a coil spring, and one end is attached to a spring hook pin 7 of the spindle 4, and the other end is attached to another spring hook pin 8 provided on the frame body 1, and the spindle 4 is always urged downward, that is, in the direction of the measuring tip 5. are doing. Reference numeral 9 denotes a guide rod, one end of which is fixed to the spindle 4, and the other end of which extends into a guide groove 1a formed in the frame 1 to restrict rotation of the spindle 4 during its movement stroke. Reference numeral 10 denotes a moving scale mounting plate fixed to the spindle 4 with screws or adhesive, to which is fixed a moving scale 11 made of a glass material having a known grid pattern. A fixed scale 12 has a grid pattern similar to the movable scale 11, and is fixed to the frame 1 via a mounting member 13 in a parallel arrangement opposite to the movable scale 11. 14 is a fixed plate 15
A pair of light emitting elements 1 fixed to the frame 1 via
Reference numeral 6 denotes a pair of light receiving elements (one of which is shown in FIG. 2) fixed to the mounting member 13 via a fixing plate 17 at a position opposite to the light emitting element 14 with the pair of scales 11 and 12 in between. It is. 18
20 is a stopper screw screwed onto the upper end surface of the spindle 4 and equipped with an O-ring 19 for mitigating the impact at the lower limit position of the spindle 4, and 20 is a stopper screw that prevents dust from entering the minute gap between the upper bushing 2 and the spindle 4. This is a cap that is screwed onto the upper bushing 2 to prevent it from falling.

In such a configuration, when the spindle 4 is moved up and down, the scale 11 also moves in the same way, so the amount of light from the light emitting element 14 changes periodically due to the moving scale 11 and the fixed scale 12. The light is transmitted to the opposing light receiving element 16. Analog periodic changes in the amount of light at the light-receiving element 16 are converted into digital quantities through known electrical circuits such as amplifiers, analog comparators, addition/subtraction direction discrimination circuits, counters, and arithmetic circuits (not shown). , the amount of movement of the spindle is finally displayed as a digital value on the display element.

In this way, compared to conventional so-called mechanical dial gauges, digital dial gauges directly display the amount of spindle movement as a digital value, so there is no misreading during measurement, and there is no need to worry about familiarity or inexperience among the measurers. Since there are no individual differences, and there is no need for a mechanical transmission mechanism such as a rack and pinion, stable and high accuracy can be obtained even over long periods of use.In addition, remote measurement is possible, and measurement data is It has become rapidly popular in recent years because it has various advantages such as automatic recording of data and the ability to process data such as calculations.

The inventors of the present invention previously proposed a new method for such digital dial gauges in order to reduce the moving speed of the spindle, prevent counting errors, and reduce the impact force on the spindle while maintaining high accuracy. We proposed the air damper mechanism shown in Figure 3.

Next, the air damper mechanism M already proposed by the present inventors will be explained with reference to FIG. Incidentally, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals, and the explanation thereof will be omitted. In FIG. 3, the screw hole 4b of the upper end surface 4a of the spindle 4 supported on the upper bushing 2 side has a barrel 21a.
A receiving screw 21 with a screw is screwed therein. Reference numeral 22 denotes a piston whose inner peripheral surface 22 a is supported by the body 21 a of the receiving screw 21 . Surface 22a and body 2
The outer peripheral surface 21b of 1a and the upper surface 2 of the piston 22
2b and the lower head surface 21c of the receiving screw 21, gaps e1 and e2 are provided, respectively. Furthermore, the third
In the figure, the gaps e1 and e2 are exaggerated. Furthermore, a ring-shaped upright portion 23 that surrounds the outer periphery of the head of the receiving screw 21 from the upper surface 22b of the piston 22 and protrudes upward longer than the length l of this head is integrally formed with the piston body 22. Reference numeral 24 denotes a sealing plate that is watertightly fixed to the opening at the upper end of the rising portion 23 of the piston 22 by means of press fitting, adhesion, or the like. Reference numeral 25 denotes a cylinder screwed to the upper bushing 2, and although its shape is no different from the cap 20 shown in FIG. The dimensions and shape are such that a gap e3 of several microns can be obtained. Even if the axis of the receiving screw 21 and the axis of the cylinder 25 are misaligned during assembly, the piston 22 can move in the radial direction in order to ensure that the preset gap e3 is obtained after assembly. Thus, the aforementioned gap e1 of several hundred microns is provided between the inner circumferential surface 22a of the piston 22 and the outer circumferential surface 21b of the body 21a of the receiving screw.

Hereinafter, in FIG. 3, for the sake of convenience, the space above the piston 22 in the cylinder 25 will be called an air chamber A, and the space below it will be called an air chamber B.

In such a structure, when the spindle 4 is moved upward, the air in the air chamber A above the piston 22 flows between the inner circumferential surface 25a of the cylinder 25 and the piston 2.
It passes through the gap e3 between the outer circumferential surface 22c of the piston 22 and is discharged into the air chamber B below the piston 22. Therefore, an air damper effect is generated on the piston 22 due to fluid resistance, and the upward movement speed of the spindle 4 is reduced. Therefore, when lifting the spindle 4 upward manually or by a release, even if the same lifting force is applied, compared to a case without the damper mechanism M, the lifting force is relaxed and the force applied to the spindle 4 is reduced. Impact force can be alleviated.

Next, when the pushing force on the spindle 4 is released, the spindle 4 is pulled down by the coil spring 6 shown in FIG.
protrudes from the frame 1. At this time, the piston 22
The air in the lower air chamber B flows through the inner circumferential surface 2 of the cylinder 25.
5a and the outer peripheral surface 22c of the piston 22
3, the air is discharged to the air chamber A above the piston 22, and the piston 2
2, an air damper effect occurs due to fluid resistance,
The downward movement speed of the spindle 4 is reduced. Therefore, the spring constant of the coil spring 6 that always urges the spindle 4 downward, and the gap e between the cylinder inner circumferential surface 25a and the piston outer circumferential surface 22c.
If the relationship between the buffering force of the air damper and the buffering force of the air damper 3 is set in advance so as not to exceed the electrical response speed of the light emitting and light receiving elements, the amount of movement of the spindle 4 can be accurately determined without causing counting errors. Even when the probe 5 of the spindle 4 comes into contact with the object to be measured, the spindle 4 protrudes while its protrusion speed is reduced, so the impact force on the spindle 4 weakens and the spindle 4 As a result, the influence of impact on the integrally fixed moving scale 11 is alleviated, resulting in stable high accuracy.

However, the air damper mechanism M shown in FIG.
When conducting experiments using the air damper mechanism M
Although very good results were obtained regarding the durability of the spindle 4 including the When installed on the machine, a problem arose in that the spindle had poor followability to the workpiece.

In order to solve the above problem, the inventors of the present invention investigated the cause and found that the speed at which the spindle protrudes from the frame is more horizontal or vertical than when the probe or stem is lower than the frame. It turns out that this is because the upside down state is much smaller.

This is because, under normal conditions, the urging force of the coil spring and the gravity of a moving object such as the spindle or moving scale act in the direction in which the spindle protrudes, and the buffering force of the damper acts in the opposite direction. However, in the horizontal state, only the biasing force of the coil spring acts in the direction in which the spindle protrudes.
A buffering force is applied by the damper in the opposite direction. In addition, when the spindle is upside down, only the biasing force of the coil spring acts in the protruding direction of the spindle.
It turns out that this is because not only the buffering force from the damper acts in the opposite direction, but also the gravity of moving objects such as the spindle and moving scale.

Therefore, when the gauge head 5 provided at the tip of the spindle 4 is lowered (the state shown in Fig. 1) and descends, a damper action occurs, and the gauge head 5 is in a horizontal state or in an upper position (the state shown in Figure 1). As a result of studying a structure in which the damper does not provide a buffering effect in the reverse state shown in the figure, the present invention shown in FIG. 4 was obtained.

The embodiment of the present invention shown in FIG. 4 will be described below. Incidentally, the same parts as in FIGS. 1 to 3 are given the same reference numerals and their explanations will be omitted.

FIG. 4 shows a state in which the spindle 4, which is equipped with the same air damper mechanism M as shown in FIG. The upper end of the cylinder 25 is covered with a control valve 100, which is the main part of the present invention.

In FIG. 4, reference numeral 30 is a valve body screwed to the upper end of the cylinder 25, and an inverted conical receiving part 32 is provided at the center of the flat plate part 31 so that the ball valve 40 can always be placed in the center position. A through hole 33 communicating with this receiving portion 32 is provided. Therefore, ball valve 4
0 is not placed, the upper chamber E and the lower chamber F, which are partitioned by the flat plate portion 31, are communicated through the through hole 33. 50 is a sealing plate provided at the open end of the upper chamber E of the valve body 30 to close off the upper chamber E.
Conical part 5 provided in the part protruding from the center
1 is provided to restrict movement of the aforementioned ball valve 40. Reference numeral 34 indicates a vent hole provided in the valve body 30 to communicate the upper chamber E with the atmosphere. Further, the lower chamber F is communicated with the cylinder 25 by screwing the valve body 30 to the cylinder 25.

In this way, the control valve 1 is placed at the upper end of the cylinder 25.
00, (1) When the gauge head 5 is in the lower position (Fig. 1), (a) When the gauge head 5 rises; initially the control valve 10
The ball valve 40 of No. 0 is placed on the receiving part 32 of the valve body 30 by its own weight, and the ventilation between the upper chamber E and the lower chamber F is interrupted. However, when the probe 5 rises, Since the lower chamber F in the cylinder 25 is compressed by the piston 22, the ball valve 40 is moved upward by the compressed air, and the air in the lower chamber F passes through the upper chamber E of the through hole 33 and the ventilation hole 34 to the outside. It will be leaked. Therefore, no damping effect occurs.

(b) When the probe 5 descends; When the spindle 4 descends from the state shown in Fig. 4, the lower chamber F is
Since the inflow of outside air is interrupted by the ball valve 40, the only air that flows into the lower chamber F is the air that passes through the gap e3 between the outer peripheral surface 22c of the piston 22 and the inner peripheral surface 25a of the cylinder 25. Therefore, this piston 22 and cylinder 25
This causes an air damper effect, and the contact point 5
The descending speed of the spindle 4 will be reduced.

(2) When the probe 5 is on the upper side (upside down in Figure 1), (a) When the probe 5 is lowered; in this state,
Since the ball valve 40 is supported by the conical portion 51 of the sealing plate 50 by its own weight, the lower chamber F is always communicated with the outside air via the through hole 33, the upper chamber E, and the ventilation hole 34. Therefore, the measuring head 5
Since the air in the lower chamber F is discharged to the outside air as the piston 22 descends, no air damper action occurs on the piston 22.

(b) When the probe 5 rises; even in this state, the ball valve 40 is supported by the conical portion 51 of the sealing plate 50 due to its own weight, so the lower chamber F is always communicated with the outside air. .

Therefore, as the probe 5 rises, outside air flows into the lower chamber F, so that the piston 22
No air damper effect occurs.

(3) When the probe is in a horizontal state In this case, the ball valve 40 is supported by both the receiving part 32 of the valve body 30 and the conical part 51 of the sealing plate 50 (indicated by the broken line in FIG. 4). ), the through hole 33 is released from the ball valve 40, and the lower chamber F is communicated with the outside air. Therefore, (2) above
Similar to the state in which the probe 5 is on the upper side, the air damper action does not work on the piston 22 during the upward and downward strokes of the probe 5.

As explained in detail above, in the present invention, a control valve mechanism is added to the air damper mechanism, so that the air damper action is performed only when the gauge head 5, that is, the spindle 4, descends when the gauge head 5 is on the lower side. When the gauge head 5 ((spindle 4) rises and descends when the gauge head 5 is horizontal or on the upper side, the air damper effect does not occur. Even when used horizontally or in an upward position, the probe's ability to follow the workpiece is extremely good, expanding the usability of the digital dial gauge, and its practical effects are extremely large. .

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the main parts of a conventional digital dial gauge, Fig. 2 is a sectional view taken along the - line in Fig. 1,
FIG. 3 is a detailed sectional view of an air damper mechanism of a conventional digital dial gauge, and FIG. 4 is a sectional view of essential parts of a digital dial gauge of the present invention equipped with a control valve mechanism. 1... Frame body, 2... Atsupatsu bushi, 3...
Stem, 4... Spindle, 11... Moving scale, 12... Fixed scale, 14... Light emitting element,
16... Light receiving element, 6... Coil spring, M... Air damper mechanism, 21... Receiving screw, 22... Piston, 24... Sealing plate, 25... Cylinder, 1
00... Control valve, 30... Valve body, 31... Flat plate part, 32... Receiving part, 33... Through hole, 34... Vent hole, 40... Ball valve, 50... Sealing plate, 51 ...Conical part, E...Upper chamber, F...Lower chamber.

Claims (1)

[Scope of utility model registration request] A spindle, which is supported by a pair of bearings fixed to a frame body and has a probe at one end so as to be slidable in the axial direction, a moving scale fixed to the spindle, and the frame at a position opposite to the moving scale. A fixed scale provided on the body, a light emitting element and a light receiving element facing each other across a pair of scales consisting of the moving scale and the fixed scale, and a coil spring that always biases the spindle toward the measuring element, A piston having a receiving screw provided on an end surface of the spindle facing the measuring head, a main body movably supported on the receiving screw, and an upright portion extending upwardly from the main body; A digital dial gauge has an air damper mechanism consisting of a cylinder and a sealing plate watertightly fixed to the opening at the upper end of the upright part. a sealing plate having a conical portion that restricts movement of a ball valve placed on a receiving portion provided at the center of the flat plate portion; a through hole communicating the receiving portion of the flat plate portion with a lower chamber; a control valve provided with a ventilation hole provided in the valve body for communicating outside air and the upper chamber, at the upper end of the cylinder;
A digital dial gauge characterized in that the lower chamber communicates with a cylinder and is covered with a cylinder.