JPH11325876A - measuring device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Simultaneous measurement of multiple points in a wide measurement range and a small pitch by measuring a reference dimension with a linear gauge and measuring a difference from a measurement value with a linear gauge with a differential transformer. Is possible. SOLUTION: In the measuring device, a differential transformer 50 is provided so as to be able to move integrally with the measuring head 44 of the linear gauge 40, and is different from a measuring element 46 of the linear gauge 40. The tracing stylus 52 of the moving transformer 50 is arranged in parallel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring, at multiple points, the outer diameter of a narrow portion sandwiched between counterweights on both sides, for example, a journal portion of a crankshaft.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring the outer diameter of a work, for example, a measuring device disclosed in Japanese Utility Model Laid-Open No. 59-138711 is known. This technology is to remotely control an air cylinder in which a dial gauge is attached to the tip of a piston rod, thereby bringing the spindle of the dial gauge into contact with the surface of a workpiece being ground and measuring the outer diameter thereof. .

A linear gauge or a differential transformer is known as a measuring device capable of measuring not only the outer diameter but also a plane or a step. In the linear gauge, a portion for detecting the amount of movement of the tracing stylus in contact with the work is configured by a combination of a digital scale using light or magnetism and a digital counter, and is capable of performing a wide range of measurement. On the other hand, the differential transformer moves a core interlocked with the movement of the tracing stylus in the coil, and takes out the induced electromotive voltage generated at this time as an electric signal, and has a good measurement accuracy and a small size.

[0004]

In the measuring apparatus using the dial gauge disclosed in the above-mentioned publication, the dial gauge is large, and in the linear gauge, the measuring apparatus itself is large. Therefore, these measuring devices can measure one point in a wide range, but it is difficult to simultaneously measure a plurality of points with a small pitch even if a plurality of these are combined. For this reason, it is impossible to simultaneously measure multiple points in a narrow place having a counter weight on both sides, such as a journal portion of a crankshaft.

On the other hand, since the differential transformer is small in size, it is possible to simultaneously measure multiple points at a small pitch by a combination thereof. However, the range in which the linearity of the induced electromotive voltage generated by the movement of the core is assured is narrow, which is not suitable for a wide range of measurement. The reason why the multiple points are measured in the measurement of the outer diameter of the journal portion or the like of the crankshaft is to check the allowable value for the taper of the journal portion or the swelling of the outer peripheral surface.

One object of the present invention is to measure a reference dimension with a linear gauge and measure a difference with a linear gauge with a differential transformer to obtain a multi-point of a small pitch with a wide measuring range. It is to enable simultaneous measurement.

Another object of the present invention is to enable simultaneous measurement of three or more points, or to easily support one-point measurement as needed.

[0008]

According to the first aspect of the present invention,
A measuring device, wherein a differential transformer is provided so as to move integrally with the measuring head of the linear gauge, and the measuring element of the linear gauge and the measuring element of the differential transformer are arranged in parallel. Are located.

According to this structure, the reference dimension is measured by the linear gauge, and the difference from the measured value by the linear gauge is measured by the differential transformer. Can be measured. Therefore, it is most suitable when measuring multiple points of the outer diameter of a narrow place such as a journal part of a crankshaft having counter weights on both sides.

According to a second aspect of the present invention, in the measuring apparatus according to the first aspect, a plurality of the differential transformers are provided. In this case, simultaneous measurement of three or more points can be performed by a combination of a linear gauge and a plurality of differential transformers.

[0011] The invention according to claim 3 is the invention according to claim 1 or 2.
The measurement device according to claim 1, wherein the differential transformer is detachable from a measurement head of a linear gauge.
Therefore, by removing the differential transformer, it is possible to perform one-point measurement using only the linear gauge.

[0012]

Embodiments of the present invention will be described below. FIG. 1 is a plan view showing an outline of measuring the outer diameter of a crankshaft. As shown in the drawing, the crankshaft 60, which is a work to be measured, has a front center 12 and a rear center 1 from both end surfaces thereof.
4 clamped. By rotating the front side center 12 by the servo motor 13, the crankshaft 60 can be rotated around its axis.

On the upper surface of the bed 10, measuring devices 20 are disposed on both left and right sides of the crankshaft 60 (upper and lower sides in FIG. 1). Both of these measuring devices 20 are controlled to move in the left-right direction in FIG. 1 by rotating the ball screw 18 by the X-axis servo motor 16. By this movement control, the later-described measuring heads 44 of both measuring devices 20 are moved in the longitudinal direction of the crankshaft 60, and the respective measuring heads 44 of the respective measuring devices 20 are moved by the Z-axis air cylinders 36. It can be approached or retracted to the measuring point.

FIG. 2 is an enlarged view as viewed from the direction of arrows II-II in FIG. 1, and FIG. 3 is an enlarged sectional view showing the measuring device 20 on the right side in FIG. As is apparent from these drawings, the movable member 22 is mounted on the frame 21 of the measuring device 20 so as to be movable in the left-right direction. That is, a pair of upper and lower rods 28 provided in a state of being bridged between the front side bracket 24 and the rear side bracket 26 of the movable member 22 move with respect to the individual guides 30 fixed inside the frame 21. And is slidably supported in the left-right direction via a stroke bearing 32.

The Z-axis air cylinder 36 is mounted on the rear surface of the frame 21. The end of a piston rod 38 of the air cylinder 36 is connected to the rear bracket 26 of the movable member 22. I have. Therefore, the movement of the movable member 22 in the left-right direction is controlled by the operation of the Z-axis air cylinder 36. As is well known, a linear gauge 40 forming a detection unit by a combination of a digital scale using light or the like and a digital counter (both not shown) is positioned at a lower position inside the frame 21 in a left-right direction. It is arranged in the posture of. The tip of the connecting rod 42 that transmits the motion to the digital scale of the linear gauge 40 is
It penetrates the frame 21 and is located on the front side thereof.

FIG. 4 is a left side view of FIG. As is apparent from this drawing, the measuring head 44 of the linear gauge 40 is fixed to the front bracket 24 of the movable member 22 by means such as bolting, and the measuring head 44 is connected to the connecting rod. 42 are joined together. As is apparent from FIG. 4, the measuring head 44 has its horizontal width set as small as possible with respect to its vertical width.

A measuring element 46 of the linear gauge 40 is provided at the center of the front surface of the measuring head 44 (FIG. 4).
In addition, differential transformers 50 for converting linear displacement into electric signals are integrally assembled with the measuring head 44 on both left and right sides of the tracing stylus 46, respectively. The tracing stylus 52 of both differential transformers 50 is a linear gauge 4
0, and the distance between these three probes 46, 52 is set to a small pitch because the two differential transformers 50 are small. .

With respect to the linear gauge 40, the movement of the tracing stylus 46 (measuring head 44) is transmitted to a digital scale, and the displacement is measured by a cooperative function of the digital scale and the digital counter. Further, the differential transformer 50 measures a displacement amount using an induced electromotive voltage generated when a ferromagnetic material (core) interlocked with the movement of the tracing stylus 52 moves in a coil (both not shown). Is done. It goes without saying that the tracing stylus 52 of the two differential transformers 50 can move relative to the measuring head 44 of the linear gauge 40.

Next, the operation of measuring the outer diameter of the crankshaft 60 will be described. First, as shown in FIG. 1, the crankshaft 60 clamped by the front center 12 and the rear center 14 is rotated by driving the servo motor 13 as described above, and is positioned at a rotation angle suitable for measuring the outer diameter. . Next, the movement of the two measuring devices 20 is controlled by the X-axis servomotor 16, and the individual measuring heads 44 are moved to the crankshaft 6.
0 (one journal part 6 in this embodiment)
Move to the position corresponding to 2). In parallel with this, the respective measurement heads 44 are brought closer to the journal portions 62 by controlling the Z-axis air cylinders 36 of both the measurement devices 20.

As a result, the two measuring heads 44 advance so as to sandwich the journal 62 from both sides, and the three tracing styluses 46 and 52 are respectively moved to the journal 6 as shown in FIG.
When the outer circumference of the measuring head 2 is hit, the advancement of both measuring heads 44 stops. At this time, the displacement amounts of the respective tracing styluses 46 and 52 are detected in both measuring devices 20, and the measurement value of the journal portion 62 is calculated by calculating the detected value. In both measuring devices 20, the linear gauge 40 measures a reference dimension (absolute value), and the differential transformer 50 measures a difference from a value measured by the linear gauge 40.

As described above, the distance between the three tracing styluses 46 and 52 in both measuring heads 44 is set small. From these facts, both measuring devices 20 can simultaneously measure three points in a wide measuring range and at a small pitch (for example, about 6.0 mm). The journal portion 62 is a narrow portion having counterweights 64 on both sides as shown in FIG. 5, but even at the outer periphery of such a journal portion 62, three points are measured at the same time and the taper or bulge of the outer peripheral surface is measured. Can be efficiently detected.

When the measurement of one journal 62 is completed in this way, the individual measuring heads 44 are retracted to the home positions by controlling the Z-axis air cylinders 36 of both measuring devices 20. Thereafter, both measuring devices 20 are moved to the next measuring point (journal part 62) by the X-axis servomotor 16.
And the Z-axis air cylinder 36 is controlled again to bring the respective measurement heads 44 closer to the current journal portion 62, and measurement is performed in the same manner as described above. Hereinafter, each of the journal portions 62 or other measurement points is measured in order while positioning the crankshaft 60 by rotating it to a predetermined rotation angle by the servo motor 13 as necessary.

As shown in FIG. 6, there are two methods for measuring the outer diameter. FIG. 6A shows a so-called “fixed-point measurement method”, in which a measurement position is determined by the two measurement devices 20 when the center of the journal section 62 does not fluctuate, and measurement is performed at that position. On the other hand, FIG. 6B shows what is referred to as a “continuous measurement method”. In the case where the axis of the journal portion 62 may fluctuate due to the bending of the crankshaft 60, the vicinity of the center of the journal portion 62 may be used. Is continuously measured in a predetermined range, and the maximum measurement value is processed as a measured value. Note that these two systems are also adopted for a master ring described below.

FIGS. 7 to 9 are explanatory views showing a mastering method of the measuring device 20. FIG. When the differential transformer 50 is used as described above, zero correction and sensitivity correction are required to maintain high measurement accuracy. First, as for the zero correction, as shown in FIG. 7, the measuring element 46 of the linear gauge 40 and the measuring elements 52a and 52b of
The outer diameter of the reference master 70 is respectively measured by this, and thereby the zero correction of the linear gauge 40 and the differential transformer 50 is performed.

Next, as shown in FIG. 8, the measuring element 52a of the differential transformer 50 located on the right side is brought into contact with the outer periphery of the sensitivity master 72, and the measuring element 46 of the linear gauge 40 and the measuring element 46 of the differential transformer 50 located on the left side. The measuring device 52 is so arranged that the probe 52b is kept in contact with the outer periphery of the reference master 70.
Move 0. In this state, each measurement is performed, and the sensitivity of the differential transformer 50 located on the right side is corrected based on the step between the reference master 70 and the sensitivity master 72.

Next, as shown in FIG. 9, the measuring device 20 is moved in the opposite direction, and the measuring element 52b of the differential transformer 50 located on the left is brought into contact with the outer periphery of the sensitivity master 74. The measurement element 46 of the reference 40 and the measurement element 52a of the differential transformer 50 located on the right side are brought into contact with the outer periphery of the reference master 70 to perform the measurement. Thereby, the sensitivity of the differential transformer 50 located on the left side is corrected based on the step between the reference master 70 and the sensitivity master 74.

In the present embodiment, the journal portion 62 of the crankshaft 60 has been described as an example of the work whose outer diameter is to be measured. However, it is natural that various other works can be used. . In addition to the measurement of the outer diameter, the use of only one of the measurement devices 20 enables the measurement of a flat surface and the measurement of a step on a flat surface. Further, by removing both differential transformers 50 from the measuring head 44 as needed, it is also possible to perform one-point measurement using only the linear gauge 40.

[Brief description of the drawings]

FIG. 1 is a plan view showing an outline when measuring an outer diameter of a crankshaft.

FIG. 2 is an enlarged view as seen from the direction of arrows II-II in FIG.

FIG. 3 is an enlarged sectional view showing the measuring device on the right side of FIG. 2;

FIG. 4 is a left side view of FIG. 3;

FIG. 5 is an explanatory diagram showing a multi-point measurement state of a journal section.

FIG. 6 is an explanatory view showing a method of measuring an outer diameter.

FIG. 7 is an explanatory diagram showing a state of zero correction for a linear gauge and a differential transformer.

FIG. 8 is an explanatory diagram showing a state of sensitivity correction for one differential transformer.

FIG. 9 is an explanatory diagram showing a state of sensitivity correction for the other differential transformer.

[Explanation of symbols]

 40 linear gauge 44 measuring head 46 measuring element 50 differential transformer 52 measuring element

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideki Machitori 9-7-1, Shimorenjaku, Mitaka-shi, Tokyo

Claims (3)

[Claims] A differential transformer is provided so as to move integrally with a measuring head of a linear gauge, and a measuring element of the linear gauge and a measuring element of the differential transformer are arranged in parallel. Measuring device. 2. The measuring device according to claim 1, wherein a plurality of the differential transformers are provided. 3. The measuring apparatus according to claim 1, wherein said differential transformer is detachable from a measuring head of a linear gauge.