JP2001027507A - Bearing gap measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing gap measuring device capable of exactly measuring the whole circle of a bearing gap and controlling the proper gap of the bearing. SOLUTION: On the outer surface of a crank shaft 20 facing a bearing cylinder 26, a first and a second displacement sensors 21A and 21B of eddy current type attached to the two symmetric measuring positions of the center of the crank shaft 20 for detecting the bearing gap with magnetic field, a rotary encoder for detecting the rotational angle of the crank shaft 20, a measuring body operating the detected value of bearing gaps ΔA and ΔB of the displacement sensors 21A and 21B to the crank angle obtained from the rotary encoder for whole circle and a display for indicating the measured value obtained with this measuring body are provided. The device is constituted to indicate the cross sectional shape of the shaft cylinder 26 on the display by rotating the rotational shaft by 180 degrees and measuring the bearing gaps ΔA and ΔB for whole circle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing clearance measuring device suitable for a crankshaft or the like having a small exposed portion of a rotating shaft outside a bearing.

[0002]

2. Description of the Related Art As shown in FIG. 8, for example, in a crankshaft 1 of a diesel engine mounted on a marine vessel, a bearing gap between the shaft 2 and a bearing 3 is an important factor for forming an oil film. Is managed. In this management method, it is considered that the shaft 2 is always in contact with the lower part of the bearing 3 due to the influence of gravity, and the management is performed by measuring a gap at a specific location on the upper part.

The measurement of the bearing clearance uses a plurality of clearance gauges 11 shown in FIG.
A measuring rod 13 having a predetermined thickness and a flexible thickness is attached to a measuring case 12 having a distal end formed in a curved portion.
The measurement case 12 is inserted from the gap between the bearing 3 and the crank arm 4 and the measurement rod 13 is pushed in by the gripping portion 13b to move the measurement portion 13a between the shaft 2 and the bearing cylinder (white metal) 3a. It is inserted in between and measured.

[0004]

However, in the above-mentioned conventional structure, if the mounting height of each bearing 3 is deviated due to the deformation of the hull or the poor installation accuracy, the bearing 2 adjacent on both sides is used for the shaft 2.
May be supported, and in such a bearing 3, the lower part of the shaft 2 does not contact the inner surface of the bearing. Therefore, even if a gap at a specific upper portion is measured, it may not be said that the data is managed with accurate data. Further, the normal bearing cylinder 3a is not a perfect circle, but has a horizontally long elliptical cross-section because it is tightened up and down, and there has been a problem that an accurate measurement value cannot be obtained by measuring only a specific portion at the top. Further, the gap gauge 11 is provided with a
There is a portion that cannot be inserted into the gap between the crank arm 4 and the bearing 3, and there is a problem that it is difficult to measure over the entire circumference.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bearing clearance measuring apparatus which can solve the above-mentioned problems and can measure the bearing clearance accurately over the entire circumference and can appropriately manage the bearing clearance.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 is provided on at least two measurement positions symmetrical to the axis of the rotating shaft on the outer peripheral surface of the rotating shaft facing the bearing. An eddy current displacement sensor that is mounted via a mounting jig and detects a bearing gap by a magnetic field that passes through the gap between the rotating shaft and the bearing, a rotation angle detector that detects a rotation angle of the rotating shaft, A measuring unit main body that stores the detected values of the eddy current displacement sensor with respect to the rotation angle detected by the angle detector, and calculates a bearing clearance on a cross section over the entire circumference from the stored values, and a measuring unit main body. And a display device for displaying the calculated values, and the bearing shaft is rotated at least 180 ° to measure the bearing clearance over the entire circumference.

According to the above arrangement, the bearing gap is measured at a fixed angle over the entire circumference of the bearing while rotating the rotary shaft by 180 ° by the displacement sensors arranged at symmetrical positions, and the bearing is rotated over the entire circumference of the rotation angle. Accurate data of the clearance can be obtained, and accurate clearance management of the bearing can be performed.

According to a second aspect of the present invention, in place of the eddy current displacement sensor, the conductive electrode is brought close to the rotating shaft and the bearing to detect the capacitance of the conductive electrode and detect the bearing gap. A sensor is provided. According to the above configuration, the same effect can be obtained even with a capacitance type displacement sensor.

Further, according to a third aspect of the present invention, the measuring section main body is configured to average bearing clearance data measured at a symmetrical position by a pair of displacement sensors and use the data as bearing inner diameter data. is there.

[0010] According to the above configuration, by measuring the symmetrical positions of the shafts and averaging these measured values, the position of the rotating shaft is deviated relative to the bearings due to gravity or the height of the adjacent bearings. Even if there is, a cross section of the bearing can be accurately obtained regardless of the case.

According to a fourth aspect of the present invention, there is provided a mounting jig having the above-mentioned structure, wherein a non-conductive sensor block for holding a displacement sensor, strip-shaped members extending in a circumferential direction from the sensor block, and these strip-shaped members. Are attached to both ends and are fixed to the rotating shaft.

According to the above configuration, even when the gap between the bearing and the crank arm is small, such as a crankshaft, the displacement sensor can be easily mounted at the target position and can be easily removed. Quick measurement is possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an embodiment of a bearing clearance measuring device according to the present invention will be described with reference to FIGS.
1 and 2, 21A and 21B are inserted through a gap 24 of about 15 mm between a bearing case (bearing base metal) 22 and a crank arm 23 and are spaced 180 ° apart from the outer peripheral surface of a crankshaft 20 which is a rotating shaft. A small (about 5 mm in total length) eddy current displacement sensor attached to the symmetrical position of the axis O by the attachment jig 25, and a magnetic field generated from a built-in sensor coil at a position separated by a certain distance δ, A change in the eddy current detected when passing through the conductor crankshaft 20 and the bearing gaps ΔA and ΔB and the bearing cylinder (white metal) 26 is detected, and the bearing gap ΔA between the crankshaft 20 and the bearing cylinder 26 is detected. , ΔB are measured.

As shown in FIGS. 3 and 4, the mounting jig 25 includes a first displacement sensor 21A and a second displacement sensor 21A.
B is mounted on the bottom of the sensor block 31 made of, for example, bakelite (phenolic resin) and settled on the outer peripheral surface of the crankshaft 20. The sensor block 31 is mounted on the sensor block 31 via a mounting nut 34. Strips 32 which are strip-shaped members and extend in the circumferential direction, and magnets 3 which are suction tools attached to both ends of the strips 32.
3 is comprised. Of course, it is arranged in a direction and a distance from the steel strip 32 that do not affect the displacement sensors 21A and 21B.

The first displacement sensor 21A and the second displacement sensor 21 are mounted on the sensor blocks 31, 31, respectively.
For B, a detection signal is output by an output cable 35 that penetrates a bolt portion of the mounting nut 34. Further, the gap δ between the bearing cylinder 26 and the first displacement sensor 21A and the gap δ between the bearing cylinder 26 and the second displacement sensor 21B are mounted to be always constant by a gap gauge or the like, and the gaps ΔA and ΔB are determined by the first displacement sensor 21A. And the output signal of the second displacement sensor 21B is obtained by data processing based on basic data obtained by conducting an experiment with a gap δ in advance.

As shown in FIG. 5, a measuring unit main body 41 composed of a computer has first
A first bearing clearance calculator 42, a second bearing clearance calculator 43, and a crank angle calculator 44 to which detection signals from the displacement sensor 21A and the second displacement sensor 21B are respectively input are provided. , 44
A measuring unit 45 for calculating the polar coordinates of the bearing clearance over 360 ° based on the calculated value output from
The data is output from the measurement unit 41 to the display device 46 or another computer.

The first bearing clearance calculating section 42 and the second bearing clearance calculating section 43 use the detection signals from the first displacement sensor 21A and the second displacement sensor 21B to determine the bearing clearances ΔA and ΔA.
B is calculated respectively. In the crank angle calculation unit 44, a pulse signal is input from a pulse detector of the rotary encoder 27, which is a rotation angle detector that is provided on the crankshaft 20 and detects a crank angle (rotation angle) θ of the crankshaft 20. Is output.

In the measuring section 45, as shown in FIG.
Corresponding to the crank angle θ, the inner radius A = d + ΔA of the bearing cylinder 25 on the first displacement sensor 21A side, the second displacement sensor 21B
Assuming that the inner radius B of the side bearing cylinder 25 is B = d + ΔB (where d is the radius of the crankshaft 20), A + B corresponding to the crank angle θ is sequentially stored. When the bearing gaps ΔA and ΔB are measured over 180 °, polar coordinates centered on the axis O are calculated for each crank angle θ and output to the display device 45 such as a CRT or a printer.

That is, as shown in FIG. 7, the polar coordinates at the crank angle θ are the coordinates (x, y) = (Gx1,
Gy1) Coordinates (x, y) on the second displacement sensor 21B side = (Gx2,
Gy2), the conversion formula is: Gx1 = (A + B) / 2 × cos θ formula Gy1 = (A + B) / 2 × sin θ formula Gx2 = (A + B) / 2 × cos (θ + 180) formula Gy2 = (A + B) ) / 2 × sin (θ + 180)... Expression, and the polar coordinate at the crank angle θ is obtained by the following expression. By outputting this to a display device, it can be displayed as a measurement figure on a 360 ° cross section shown in FIG.

In the above configuration, when measuring, the first displacement sensor 21A and the second displacement sensor 21B with the mounting jig 24 are inserted from the gap 24 between the bearing case 22 and the crank arm 23, and the outer peripheral surface of the crankshaft 20 is measured. The sensor block 31 of the mounting jig 24 is mounted at a measurement position 180 ° apart by the strip 32 and the magnet 33. Then, the gap δ between the first displacement sensor 21A and the second displacement sensor 21B, the bearing case 22 (the bearing cylinder 26) is adjusted using the gap gauge.

When the measurement is started, the crankshaft 20
Is slowly rotated in a predetermined direction, a measurement value is acquired at each set fixed angle, stored in the measurement unit main body 41, and the measurement is terminated at a position where the crankshaft 20 is rotated by 180 °. The calculation processing is performed based on all the stored data measured by the measurement unit main body 41, and the calculation result is output to the display device 46, and the sectional shape of the bearing cylinder 26 is displayed over the entire circumference.

According to the above embodiment, the pair of displacement sensors 21A and 21B arranged at symmetrical positions rotate the crankshaft 20 by 180 °, so that the bearing cylinder 26
, The bearing gaps ΔA and ΔB can be measured over the entire circumference, accurate data can be obtained over the entire circumference, and proper management of the bearing gap becomes possible.

In the measuring section 45 of the measuring section main body 41,
The bearing clearance data ΔA, ΔB measured at the symmetrical position by the pair of displacement sensors 21A, 21B are respectively added, divided by the number of displacement sensors 21A, 21B: 2, and averaged.
From the values A and B obtained by adding the radius d of the crankshaft to the coordinate position with respect to the crank angle θ on the polar coordinate centered on the axis O, the bearing cylinder is caused by gravity and the height of the adjacent bearing. Even if the crankshaft 20 is biased with respect to the crankshaft 26, an accurate cross-sectional shape of the bearing cylinder 26 can be obtained regardless of the bias.

Further, the mounting jig 25 for the displacement sensors 21A and 21B is composed of a non-conductive sensor block 31, a steel strip 32 extending in the circumferential direction, and magnets 33 mounted on both ends of the steel strip 32. Therefore, even if the gap 24 between the bearing case 22 and the crank arm 23 is narrow as in the case of the crankshaft 20, the displacement sensors 21A and 21
1B can be easily and quickly attached to the target position,
In addition, removal can be easily performed, and quick measurement can be performed.

In the above embodiment, the eddy current type displacement sensors 21A and 21B are used. However, instead of this, the conductive electrodes are brought closer to the crankshaft 20 and the bearing tube 26 to reduce the capacitance of the conductive electrodes. The same operation and effect can be obtained by using a capacitance type displacement sensor that detects and detects the bearing gaps ΔA and ΔB.

Further, in the above-described embodiment, the bearing clearance of the crankshaft 20 of the engine has been described.

Furthermore, although the description has been made with reference to the measurement of only one side of the bearing, the displacement sensor 21 is positioned at the same angular position on both sides of the bearing.
A and 21B can be further arranged to simultaneously measure from both sides of the bushing 26.

Although a pair of displacement sensors are attached to the crankshaft 20, two or four displacement sensors may be attached for every 90 ° or three to six for every 60 °. Rotation angles of the crankshafts 20 are 90
{, 60}.

[0029]

As described above, according to the first aspect of the present invention, the displacement sensor arranged at a symmetrical position rotates the rotary shaft by 180 ° and at a constant angle over the entire circumference of the bearing. , And accurate data of the bearing clearance can be obtained over the entire circumference of the rotation angle, and proper bearing clearance management becomes possible.

According to the second aspect of the present invention, even if a capacitance type displacement sensor is used instead of the eddy current type displacement sensor,
Similar effects can be obtained.

Further, according to the third aspect of the invention, by measuring the symmetrical position of the shaft and averaging these measured values, the bearing is rotated relative to the bearing due to gravity and the height of the adjacent bearing. Even if the shaft is unbalanced, an accurate cross-section of the inner diameter of the bearing can be obtained regardless of the deviation.

Furthermore, according to the invention of claim 4,
Even when the gap between the bearing and the crank arm is narrow, as in the case of a crankshaft, the displacement sensor can be easily mounted at the target position, and can be easily removed, thereby enabling quick measurement.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a bearing clearance measuring device according to the present invention and showing a mounted state of a displacement sensor.

FIG. 2 is a cross-sectional view of the crankshaft showing a mounted state of a displacement sensor of the bearing clearance measuring device.

FIG. 3 is a front view showing a mounting jig for the displacement sensor.

FIG. 4 is a plan view showing a mounting jig for the displacement sensor.

FIG. 5 is a configuration diagram showing the bearing clearance measuring device.

FIG. 6 is a flowchart showing a measurement procedure by the bearing clearance measurement device.

FIG. 7 is a display diagram showing an example of a measurement chart displayed by a display device of the bearing clearance measuring device.

FIG. 8 is a schematic diagram showing a configuration of a conventional crankshaft.

FIG. 9 is a perspective view showing a conventional gauge for measuring a bearing clearance of a crankshaft.

FIG. 10 is a cross-sectional view showing a measurement state of a bearing clearance of a conventional crankshaft.

[Explanation of symbols]

 Reference Signs List 20 crankshaft 21A first displacement sensor 21B second displacement sensor 22 bearing case 23 crank arm 25 mounting jig 26 bearing cylinder 27 rotary encoder 31 sensor block 32 steel strip 33 magnet 41 measuring unit main body 42 first bearing clearance calculating unit 43 2 Bearing clearance calculation unit 44 Crank angle calculation unit 45 Measurement unit 46 Display device ΔA, ΔB Bearing clearance θ Crank angle O Crankshaft shaft center d Crankshaft radius

Continued on the front page F term (reference) 2F063 AA20 AA23 AA35 AA46 BA03 BA07 BB05 DA01 DA08 DB07 DD03 EA03 EA20 GA08 HA01 LA16 MA04 ZA01 ZA04

Claims (4)

[Claims] At least two measurement positions symmetrical with respect to the axis of the rotating shaft are mounted on the outer peripheral surface of the rotating shaft facing the bearing via mounting jigs, and the gap between the rotating shaft and the bearing is transmitted through the gap therebetween. An eddy current displacement sensor that detects a bearing gap with a rotating magnetic field; a rotation angle detector that detects the rotation angle of a rotating shaft; and an eddy current displacement sensor that detects the rotation angle detected by the rotation angle detector. A measuring unit main body for storing and calculating the bearing clearance on the cross section over the entire circumference from the stored values; and a display device for displaying the calculated value obtained by the measuring unit main body. A bearing clearance measuring device characterized in that the bearing clearance is measured over the entire circumference by rotating. 2. An electrostatic displacement type sensor for detecting a capacitance of a conductive electrode by bringing a conductive electrode close to a rotating shaft and a bearing and detecting a bearing gap in place of the eddy current type displacement sensor. The bearing clearance measuring device according to claim 1, wherein: 3. The bearing unit according to claim 1, wherein the measurement unit main body is configured to average bearing clearance data measured at respective symmetrical positions by a pair of displacement sensors and use the data as bearing inner diameter data. 2. The bearing clearance measuring device according to 2. 4. A mounting jig, a non-conductive sensor block for holding a displacement sensor, belt-like members extending in a circumferential direction from the sensor block, and fixed to a rotating shaft attached to both ends of these belt-like members. 3. The bearing clearance measuring device according to claim 1, wherein the bearing clearance measuring device is constituted by a possible suction tool.