JPH08136370A - Load-measuring apparatus for roller bearing - Google Patents

Abstract

PURPOSE: To correctly measure a load impressed to a roller bearing. CONSTITUTION: An inner ring 14 of a roller bearing is outfitted and supported at a front end part of a shaft 21 supported in the cantilever structure. A through hole 29 is formed at a middle part of the shaft 21. Strain gauges 33a, 33d are attached to the inner surface of the through hole 29. Alternatively, strain gauges are attached to two faces orthogonal to each other which constitute the outer peripheral surface of a quadrangular prism part formed at the middle part of the shaft. Detecting signals by the strain gauges 33a, 33d are processed by a controller 38 including an operational device 35. Since it is not necessary to process the inner ring 14 or an outer ring 16, e.g. by notching or true like, the load impressed to the roll bearing can be correctly measured without being influenced by the notching or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A load measuring device for rolling bearings according to the present invention is used for accurately measuring a load applied to a radial rolling bearing including a ball bearing, a roller bearing and a tapered roller bearing in a rotating state. .

[0002]

2. Description of the Related Art For example, it is necessary to measure the load applied to a rolling bearing during operation in order to know the durability of rolling bearings incorporated in various mechanical devices and to assist in designing these mechanical devices. As a load measuring device for rolling bearings used for this purpose, Japanese Patent Publication No. 52-10027 discloses a measuring device as shown in FIGS.

A rotating shaft 2 is provided inside a cylindrical housing 1.
Are rotatably supported by a pair of rolling bearings 3a and 3b. Each of these rolling bearings 3 which are tapered roller bearings
a and 3b respectively include outer rings 4a and 4b fitted and fixed to the housing 1 and inner rings 5a and 5b fitted and fixed to the rotating shaft 2. Then, the respective outer rings 4a, 4
outer ring raceways 6a, 6b provided on the inner peripheral surface of b and the inner rings 5 described above.
A plurality of rolling elements 8 and 8 (taper rollers) are provided between the inner ring raceways 7a and 7b formed on the outer peripheral surfaces of a and 5b, respectively.
Is provided. Notches 9 and 9 having a shape as shown in FIG. 8 are provided on the outer peripheral surfaces of the outer rings 4a and 4b, and strain gauges 10 and 10 (strain gauges) are attached to the bottoms of the notches 9 and 9. ing. These strain gauges 10,
The detection signal of 10 is taken out by the lead wires 39, 39.

The outer rings 4a, 4b are elastically deformed according to the load (radial load and thrust load) applied between the housing 1 and the rotary shaft 2, and the strain gauges 1 are
0 and 10 detect this elastic deformation. Therefore, the load can be obtained by sending the detection signals of the strain gauges 10 and 10 to the calculator (not shown) through the conductors 39 and 39. If a notch is formed on the inner peripheral surface of the inner rings 5a, 5b and a strain gauge is attached to the bottom of the notch, the load can be measured while the outer rings 4a, 4b are rotating.

[0005]

However, the conventional load measuring device for rolling bearings constructed and operated as described above cannot always perform accurate measurement. That is, the outer ring 4
The notches 9 and 9 formed on the outer peripheral surfaces of a and 4b (or the inner peripheral surfaces of the inner rings 5a and 5b) are used only to install the strain gauges 10 and 10 for load measurement, and are rolling bearings. It is not inherent in 3a and 3b. Therefore, the notches 9 and 9 are formed to form the outer rings 4a and 4a.
As the wall thickness of b becomes thinner at the relevant portion, the elastic deformation state of each outer ring 4a, 4b is different from that of the original rolling bearings 3a, 3b (without the notches 9 and 9). Error.

In addition to this, as a load measuring device for bearings,
The one described in Japanese Examined Patent Publication No. 59-25167 is known. The measuring device described in this publication has a strain gauge attached to the outer peripheral surface of a bearing. However, a load to be measured is applied to the strain gauge without affecting elastic deformation of the bearing. Structure is not described. In view of such circumstances, the load measuring device for rolling bearings of the present invention has been invented so as to prevent the elastic deformation of the rolling bearing from being affected by installing a strain gauge.

[0007]

All of the load measuring devices for rolling bearings according to the present invention include an inner ring having an inner ring raceway on the outer peripheral surface, an outer ring having an outer ring raceway on the inner peripheral surface, and the inner ring raceway and the outer ring raceway. The load applied to the rolling bearing provided with the plurality of rolling elements provided in is measured with the inner ring fixed and the outer ring rotating.

Among such load measuring devices for rolling bearings according to the present invention, the load measuring device for rolling bearings according to claim 1 is supported in a cantilever manner, and the inner ring is externally fitted and fixed to the tip portion thereof. A shaft, a through hole formed in the middle portion of the shaft in a direction perpendicular to the axis, a strain gauge attached to the inner surface of the through hole, and a load applied to the rolling bearing based on a detection signal of the strain gauge. And an arithmetic unit for calculating

According to a second aspect of the present invention, there is provided a load measuring device for rolling bearings, which is provided in an intermediate portion of a shaft which is supported in a cantilever manner and externally fits and fixes the inner ring on the tip portion thereof.
A quadrangular prism portion having a quadrangular cross-sectional shape, and strain gauges attached to at least two mutually orthogonal planes of the four planes forming the outer peripheral surface of the quadrangular prism portion, and based on the detection signal of this strain gauge And a calculator for calculating the load applied to the rolling bearing.

[0010]

The shaft is elastically deformed by the load applied to the rolling bearing during the measurement work by the load measuring device for rolling bearings of the present invention constructed as described above, and this elastic deformation amount is the inner surface of the through hole (in the case of claim 1). ), Or the outer peripheral surface of the square pole portion (claim 2
In the case of 1), the strain gauge is provided. Then, the calculator calculates the load applied to the rolling bearing. In the case of the load measuring device for rolling bearings according to the present invention, since the strain gauge is not directly attached to the rolling bearings, it is not necessary to process the components of the rolling bearings so as to affect the measured values. As a result, highly reliable measurement results can be obtained.

[0011]

1 and 2 show a first embodiment of the present invention corresponding to claim 1. In this embodiment, the load applied from the belt 32 to the deep groove type ball bearing 12 supporting the pulley 11 is measured. The deep groove type ball bearing 12 which is a kind of rolling bearing has a deep groove type inner ring raceway 13 on its outer peripheral surface.
An inner ring 14 having an inner ring surface, an outer ring 16 having a deep groove type outer ring raceway 15 on the inner peripheral surface thereof, and balls 17 and 1 provided between the inner ring raceway 13 and the outer ring raceway 15, each being a rolling element.
7 and 7. The balls 17, 17 are rotatably held by a cage 18. Such a deep groove type ball bearing 12
When measuring the load applied to the outer ring 16, the outer ring 16 is rotated together with the pulley 11. The inner ring 14 remains fixed and does not rotate. That is, at the time of measurement work, the belt 32 is stretched between the pulley 11 and a drive pulley (not shown), and the pulley 11 and the outer ring 16 are rotationally driven.

A load measuring device for rolling bearings configured to measure a load applied to such a deep groove type ball bearing 12 includes a fixed supporting leg 20 and a shaft 21 supported by the supporting leg 20 in a cantilever manner. Have and. The shaft 21 has a base end (see FIGS.
2 the mounting flange 22 on the left end portion of FIG.
The male screw portion 23 is provided at each of the right end portions thereof. Further, a quadrangular prism portion 24 is provided in the middle portion, the quadrangular prism portion 24 and the mounting flange 22 are formed by a large-diameter column portion 25, and the square column portion 24 and the male screw portion 23 are formed by a small-diameter column portion 26. Each is continuous. The square column portion 24 has a square cross section. And this cross-sectional shape (square)
The diameter of the largest inscribed circle is larger than the outer diameter of the small-diameter cylindrical portion 26, and the diameter of the smallest circumscribed circle is the same as the large-diameter cylindrical portion 25.
Smaller than the outer diameter of

The shaft 21 as described above has the large-diameter cylindrical portion 25.
Is fitted in a circular hole 27 formed in the support leg 20, and the mounting flange 22 is screwed and coupled to the support leg 20, so that the support leg 20 is supported in a cantilever manner. In this state, the small diameter cylindrical portion 26 at the tip of the shaft 21
The inner ring 14 is externally fitted to the inner ring 14, and the inner ring 14 is fixed by a nut 28 screwed to the male screw portion 23.

On the other hand, a through hole 29 is formed in the square pole portion 24.
Is in the direction perpendicular to the axis of the shaft 21 and is in the square pole portion 24.
It is formed parallel to the upper and lower two surfaces of the four surfaces constituting the outer surface of the. In the case of the illustrated embodiment, the through hole 29 is formed by connecting a pair of circular hole portions 30, 30 parallel to each other with a slit-shaped communicating portion 31. The through hole 29 is formed in the direction of the load applied from the belt 32 to the shaft 21 (see FIG. 1).
(Downward), and is formed in a direction having a positional relationship of twist (front-back direction in FIG. 1). In addition, in order to form the through hole 29, the square pillar portion 24 is formed in the middle portion of the shaft 21.
The elastic deformation of the shaft 21 in the bending direction is the same as that of the through hole 2
This is because the measurement sensitivity is improved by connecting with the elastic deformation of the inner surface.

Strain gauges 33a to 33d are attached to the inner surface of the through hole 29 as described above. In the case of the illustrated embodiment, the strain gauges 33a and 33b are respectively provided with circular holes 30,
The strain gauges 33c and 33d are attached along the axial direction of 30 (the front and back directions in FIG. 1, the up and down direction in FIG. 2), and the circumferential directions of the circular hole portions 30 and 30 (the left and right directions in FIGS. 1 and 2), respectively. It is attached to. The detection signals of the strain gauges 33a to 33d are supplied to the controller 3 including the calculator 35 by the conductor 34.
I am typing in 8. The calculator 35 calculates the load applied to the deep groove type ball bearing 12 based on the detection signals sent from the strain gauges 33a to 33d.
The controller 38 is provided with a dynamic distortion amplifier 36 and an A / D converter 37 before the calculator 35. The detection signal is amplified by passing through the dynamic distortion amplifier 36,
The signal is converted into a digital signal by passing through the / D converter 37 and then sent to the arithmetic unit 35.

During the measurement work by the load measuring device for rolling bearings of the present invention having the above-described structure, the shaft 21 is rotated by the belt 3
Deep groove ball bearing 12 through pulley 11 based on the tension of 2
It is elastically deformed by the load applied to. At this time, the amount of deformation is proportional to the magnitude of the load. The elastic deformation occurs in the direction in which the lower half of the shaft 21 is compressed and the upper half is expanded. Therefore, the inner peripheral surfaces of the upper half portions of the circular hole portions 30, 30 are elastically deformed in the direction of increasing the radius of curvature. Each of the strain gauges 33a to 33d attached to the inner peripheral surface induces a detection signal of an output corresponding to the load, and sends the detection signal to the controller 38 through the lead wire 34. Then, the arithmetic unit 35 of the controller 38
Calculates the load applied to the deep groove type ball bearing 12.

Particularly, in the case of the load measuring device for rolling bearings of the present invention, the strain gauges 33a to 33d for load detection are used.
Is attached to the shaft 21 supporting the deep groove type ball bearing 12 and is not directly attached to this deep groove type ball bearing 12. Therefore,
The components of the deep groove ball bearing 12, such as the inner ring 14 and the outer ring 16, do not need to be processed such as notches to affect the measured values. As a result, highly reliable measurement results can be obtained.

Next, an experiment conducted by the present inventors to confirm whether or not the load applied to the deep groove type ball bearing 12 can be actually measured by the load measuring device for rolling bearings shown in FIGS. The first experiment) will be explained. Before starting this first experiment, the adjustment work of the dynamic strain amplifier 36 was first performed. In this adjustment work, after tightening the nut 28 to fix the inner ring 14, a predetermined amount of load is applied to the deep groove type ball bearing 12 via the pulley 11 without the belt 32 hanging on the pulley 11. Then, this load and the calculated value of the calculator 35 are made to coincide with each other. At the same time, it was confirmed that the detection signals of the strain gauges 33a to 33d have linearity in the range of 0 to 500 kgf.

After completing the above initial setting, a belt 32 was stretched over the pulley 11, and a predetermined radial load was applied to the pulley 11 by the belt 32. The deep groove ball bearing used in the experiment was made by the applicant company and has a serial number of 6
No. 303 (outer diameter = 47 mm, inner diameter = 17 mm, width = 14 mm) was used. The radial load was set to 100 kgf and 200 kgf. The results are shown in Table 1 below.

[0020]

[Table 1]

In Table 1, the conditions 1 and 2 are that the use of an eccentric pulley as the pulley 11 results in the deep groove ball bearing 1 described above.
Condition where the radial load applied to 2 is changed, Conditions 3, 4
Is 1000 to 5000 with a rotation speed of 10 seconds as one cycle.
The radial load was changed by changing it in the range of rpm, and the conditions 5 and 6 were the radial load being changed by applying vibration to the belt 32 with a vibrator. As is clear from the description in Table 1 showing the results of such experiments, the load measuring device for a rolling bearing of the present invention can measure the load actually applied to the deep groove ball bearing 12 and its variation. The measurement result under the condition 1 is shown in a graph in FIG. The cycle of load fluctuation shown in FIG. 3 completely coincided with the cycle of rotation of the eccentric pulley.

Next, FIGS. 4 to 6 correspond to claim 2.
2 shows a second embodiment of the present invention. In this embodiment, the load applied to the deep groove type ball bearing 12 supporting the pulley 11 from the belt 32 in an oblique direction is measured. A quadrangular prism portion 24a having a square cross section is provided in an intermediate portion of a shaft 21a supported in a cantilever manner on the fixed support leg 20.
Unlike the case of the first embodiment described above, this square pole portion 2
The through hole 29 (FIGS. 1 and 2) is not formed in 4a, and is merely a (solid body) square column portion 24a. Two of the four surfaces forming the square pole portion 24a are arranged in the vertical direction, and the remaining two surfaces are arranged in the horizontal direction.

Four strain gauges 33a to 3a are provided on the upper surface and one side surface of the square pole portion 24a.
3d and 33a 'to 33d' are attached. In the case of the illustrated embodiment, the strain gauges 33a, 33a '33b, 33
b'is attached across the width of each surface, and each strain gauge 33
c, 33c ', 33d, and 33d' are attached along the lengthwise direction of each surface (left-right direction in FIGS. 4 to 5). These strain gauges 33a to 33d, 33a 'to 33d'
The detection signal of the conductor 34 is the same as that of the first embodiment described above.
Is input to the controller 38 including the calculator 35. This embodiment is different from the above-described first embodiment in that the strain gauges 33a to 33a are used to measure the load applied in the tilt direction.
d, 33a 'to 33d' are attached to the upper surface and one side surface of the square pole portion 24a. Since other points are the same as the above-described first embodiment in many respects, the same reference numerals are given to the same portions, and duplicate description will be omitted.

During the measurement work by the load measuring device for rolling bearings of the present invention constructed as described above, the shaft 21a is deep groove type ball bearing 1 through the pulley 11 based on the tension of the belt 32.
It is elastically deformed by the load applied to 2. At this time, the amount of deformation is proportional to the magnitude of the load. As shown in FIG.
The elastic deformation occurs in a state where the upper half and the left half of the shaft 21a are compressed and the lower half and the right half extend while the belt 32 is stretched from the pulley 11 in the upper left direction. Then, the strain gauges 33a to 33d, 33a 'attached to the upper surface and one side surface of the square pole portion 24a.
.About.33d 'cause an output detection signal corresponding to the load, and send the detection signal to the controller 38 through the lead wire 34. Then, the calculator 35 of the controller 38 calculates the radial load F applied to the deep groove type ball bearing 12. Particularly in the case of this embodiment, the load F applied in the horizontal direction
_x is detected by the strain gauges 33a ′ to 33d ′ attached to one side surface of the square pole portion 24a, and the load F _y applied in the vertical direction is detected by the strain gauges 33a to 33d attached to the upper surface of the square pole portion 24a. To do. Then, the radial load F is calculated as a resultant force (F = √ (F _x ² + F _y ² )) of the loads F _x and F _{y in} both directions.

Also in the case of this embodiment, the strain gauges 33a to 33d and 33a 'to 33d' for load detection are attached to the shaft 21a for supporting the deep groove type ball bearing 12, and the deep groove type ball bearing 12 is attached to the shaft 21a. Since it is not attached directly to, it is possible to obtain highly reliable measurement results. In particular, in the case of the load measuring device for rolling bearings of the present embodiment, even if the direction of the load applied from the belt 32 to the deep groove ball bearing 12 does not coincide with the direction of the surface forming the square pole portion 24a, this load Can be measured accurately.

Next, an experiment conducted by the present inventor to confirm whether the load applied to the deep groove ball bearing 12 can be actually measured by the load measuring device for rolling bearings shown in FIGS. The second experiment) will be explained. When starting the second experiment, the dynamic strain amplifier 36 is adjusted as in the case of the first experiment described above, and the detection signals of the strain gauges 33a to 33d and 33a 'to 33d' are sent. The initial setting was performed to confirm that the film has linearity in the range of 0 to 500 kgf. After this initial setting is completed, a belt 32 is stretched between a pulley 11 fitted and fixed to the deep groove type ball bearing 12 and a drive pulley 41 driven by a motor 40, and the belt 32 causes the pulley 11 to have a predetermined radial radius. A load was applied. The deep groove type ball bearing used in the experiment is the same as the first experiment described above. The results are shown in Table 2 below.

[0027]

[Table 2]

In Table 2, conditions 1 to 4 are obtained by using an eccentric pulley as the pulley 11 so that the deep groove ball bearing 1
The radial load applied to 2 is changed, and the conditions 1 to
No. 2 is the rotation speed of the pulley 11 is 1000 rpm. Conditions 3 to 4 are the rotation speed of the pulley 11 is 5000 rpm.
m. Also, the conditions 5 and 6 set the rotation speed to 10
The radial load is varied by changing the cycle within a range of 1000 to 5000 rpm with one cycle as second. As is clear from the description of Table 2 showing the test results, the deep groove ball bearing 12 is actually used by the load measuring device for the rolling bearing of the second embodiment as in the case of the first embodiment. It is possible to measure the load applied to and its variation. Also in the case of this embodiment, the load fluctuates under the conditions 1 to 4 as shown in FIG. 3, and the cycle of this fluctuation completely coincides with the cycle of rotation of the eccentric pulley.

It is also possible to attach a strain gauge to only one surface of the quadrangular prism portion 24a and measure the load applied in a direction perpendicular to the one surface with the measuring device shown in FIGS. If the load applied in the direction perpendicular to one surface is measured in this way, the device shown in FIGS. 1 and 2 has better measurement accuracy. Further, the rolling bearing whose load can be measured by the measuring device of the present invention is not limited to the single row deep groove type ball bearing as illustrated. It is possible to measure the load applied to angular type ball bearings, roller bearings and tapered roller bearings. Further, the load applied to the entire rolling bearing can be accurately measured not only in the single-row rolling bearing but also in the double-row rolling bearing.

[0030]

Since the load measuring device for rolling bearings of the present invention is constructed and operates as described above, the following effects can be obtained. Since the measurement can be performed with the original shape of the rolling bearing,
It is possible to obtain accurate measurement results that match actual usage conditions. Since the strain gauge is incorporated inside the shaft, the entire device can be made compact and lightweight. Since the strain gauge is not particularly restricted except that it is deformed according to the load to be measured, the measured value based on the detected value of the strain gauge becomes accurate.

Further, the load measuring device for rolling bearings according to the second aspect can perform measurement without specifying the direction of the radial load, so that the measurement according to the actual use condition can be easily performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of a measuring apparatus of the present invention.

FIG. 2 is a view of only the shaft taken out and viewed from above in FIG.

FIG. 3 is a graph showing measurement results.

FIG. 4 is a diagram showing the overall configuration of a second embodiment of the measuring apparatus of the present invention.

FIG. 5 is a perspective view showing only the shaft.

FIG. 6 is a front view showing a state in which a motor and a drive pulley are combined for measurement.

FIG. 7 is a partial cross-sectional view showing an example of a conventional measuring device.

FIG. 8 is a partially enlarged perspective view of an outer ring.

[Explanation of symbols]

1 Housing 2 Rotating shafts 3a, 3b Rolling bearings 4a, 4b Outer ring 5a, 5b Inner ring 6a, 6b Outer ring raceway 7a, 7b Inner ring raceway 8 Rolling element 9 Notch 10 Strain gauge 11 Pulley 12 Deep groove ball bearing 13 Inner ring raceway 14 Inner ring 15 Outer ring raceway 16 Outer ring 17 Ball 18 Cage 20 Support leg 21, 21a Shaft 22 Mounting flange 23 Male screw part 24, 24a Square column part 25 Large diameter column part 26 Small diameter column part 27 Circular hole 28 Nut 29 Through hole 30 Circular hole part 31 Communication part 32 Belts 33a, 33a ', 33b, 33b', 33c, 33
c ′, 33d, 33d ′ Strain gauge 34 Conductor 35 Operator 36 Dynamic strain amplifier 37 A / D converter 38 Controller 39 Conductor 40 Motor 41 Drive pulley

Claims (2)

[Claims] 1. A load applied to a rolling bearing including an inner ring having an inner ring raceway on an outer peripheral surface, an outer ring having an outer ring raceway on an inner peripheral surface, and a plurality of rolling elements provided between the inner ring raceway and the outer ring raceway. The above is a load measuring device for rolling bearings, wherein the inner ring is fixed and the outer ring is rotated, and a shaft that is supported in a cantilever manner and externally fits and fixes the inner ring to the tip end thereof,
A through hole formed in the intermediate portion of the shaft in a direction perpendicular to the axis, a strain gauge attached to the inner surface of the through hole, and a load applied to the rolling bearing is calculated based on a detection signal of the strain gauge. A load measuring device for rolling bearings including a calculator. 2. A load applied to a rolling bearing including an inner ring having an inner ring raceway on an outer peripheral surface, an outer ring having an outer ring raceway on an inner peripheral surface, and a plurality of rolling elements provided between the inner ring raceway and the outer ring raceway. The above is a load measuring device for rolling bearings, wherein the inner ring is fixed and the outer ring is rotated, and a shaft that is supported in a cantilever manner and externally fits and fixes the inner ring to the tip end thereof,
A quadrangular prism portion having a quadrangular cross-sectional shape, which is provided in the middle portion of the shaft, and a strain gauge attached to at least two mutually orthogonal planes of the four planes forming the outer peripheral surface of the quadrangular prism portion. And a load measuring device for a rolling bearing, comprising: a calculator for calculating a load applied to the rolling bearing based on a detection signal of the strain gauge.