JPH0961268A - Load measuring apparatus for bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain accurate measurement matching actual use by attaching a distortion gage to the bottom of a recessed groove formed in parallel with a track face along the entire periphery on the outer face of a track wheel and calculating a load applied to a bearing from its detection signal. SOLUTION: A recessed groove 14 having a rectangular cross section is formed along the entire periphery at the center of an axial direction on an outer peripheral face of an outer wheel 11 of a radial ball bearing. Width and depth sizes of the groove 14 are constant over the circumference, wherein in order to reduce influence of existence of the groove 14 to elastic deformation of the outer wheel 11, its width is made smaller than a width of an outer wheel track 12, while in order to reduce influence of existence of an inner side 17 of the groove 14 to measurement values of a gage 16, width of the groove 14 is preferably made larger than a size of the gage 16 by approximately 10% or more. A plurality of gages 16 are attached with equal intervals along the circumference on the bottom 15 of the recess 14, wherein their detection signals are input to a controller to detect a load applied to the radial ball bearing incorporating the outer wheel 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The load measuring device for a bearing according to the present invention is designed to measure the load applied to radial rolling bearings including ball bearings, roller bearings and tapered roller bearings, various types of thrust rolling bearings, and sliding bearings. It is used as it is for accurate measurement. The bearing load measuring device of the present invention as described above is used, for example, to determine the durability of a bearing for supporting a crankshaft of an internal combustion engine, a bearing for an auxiliary machine, a bearing for an underbody, or the like.

[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 bearing load measuring device 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 conductors 20 and 20.

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 20 and 20. 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 bearing load measuring device configured and operating as described above cannot always perform accurate measurement. That is, the notches 9 and 9 formed on the outer peripheral surfaces of the outer rings 4a and 4b (or the inner peripheral surfaces of the inner rings 5a and 5b) are the strain gauges 1 for load measurement.
Rolling bearing 3 for installing 0, 10
It is not inherent in a and 3b. Therefore, since the notches 9 and 9 are formed and the thickness of the outer rings 4a and 4b is reduced at the corresponding portions, the outer rings 4a and 4b are reduced.
The elastically deformed state of 4b is (the notches 9 and 9 are not provided)
Unlike the original rolling bearings 3a and 3b, an error occurs in the measured value. In particular, since the notches 9 and 9 are provided partially or intermittently in the circumferential direction, stress concentration occurs in the portion where the notches 9 and 9 are formed. As a result, the load distribution in the circumferential direction is the original rolling bearing 3a,
It is different from 3b, and it is difficult to perform accurate measurement.

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. Therefore, even in the case of the measuring device described in this publication,
The load distribution in the circumferential direction is different from that of the original rolling bearing, and it is considered that accurate measurement cannot be performed. In view of such circumstances, the bearing load measuring device of the present invention was invented in order to eliminate the influence of the strain gauge installed on the elastic deformation of the rolling bearing.

[0007]

The bearing load measuring apparatus of the present invention measures a load acting on a bearing including a bearing ring having a raceway on one surface. The bearing load measuring device of the present invention as described above is provided with a concave groove formed on the entire other surface of the race ring in parallel with the raceway surface, and at least one strain gauge attached to the bottom surface of the concave groove. And a calculator that calculates the load applied to the bearing based on the detection signal of the strain gauge.

[0008]

The bearing ring is elastically deformed by the load applied to the bearing during the measurement work by the bearing load measuring apparatus of the present invention constructed as described above, and the amount of this elastic deformation is attached to the bottom surface of the groove. Detected by. Then, the calculator calculates the load applied to the bearing. In particular, in the case of the bearing load measuring device of the present invention, since the concave groove for attaching the strain gauge is formed parallel to the raceway surface over the entire circumference of the race, the existence of this concave groove The influence on the elastic deformation of the bearing ring is small. That is, even if the rigidity of the bearing ring is reduced due to the formation of the concave groove, this reduction in rigidity occurs uniformly over the entire circumference. Therefore, by forming the groove, stress concentration does not occur in a part in the circumferential direction. In other words, since the concave groove does not locally change the rigidity of the bearing ring in the circumferential direction, it is possible to accurately obtain the distribution of the load applied to the bearing ring, and to obtain a highly reliable measurement result. can get.

[0009]

1 to 3 show a first embodiment of the present invention. This embodiment is for measuring the load applied to the outer ring 11 of the radial ball bearing. An outer ring raceway 12 is formed at the axially central portion of the inner peripheral surface of the outer ring 11. Such an outer ring 11 constitutes a radial ball bearing in combination with a plurality of balls 13 which are one type of rolling elements and an inner ring (not shown). The plurality of balls 13 are rotatably held by a cage as necessary.

A concave groove 14 having a rectangular cross-section is formed on the outer peripheral surface of the outer ring 11 in the central portion in the axial direction over the entire circumference. The width dimension and the depth dimension of the groove 14 are constant in the circumferential direction. The width W ₁₄ of the groove 14 is smaller than the width W ₁₂ of the outer ring raceway 12 (W _{14) in} order to minimize the influence of the existence of the groove 14 on the elastic deformation of the outer ring 11. <W ₁₂ ) is preferable. By restricting the width dimensions W ₁₄ and W ₁₂ in this manner, the outer ring 11 having the concave groove 14 can be prevented from being elastically deformed differently from the original by providing the concave groove 14. However, the width dimension W ₁₄ of the groove 14 is set to the strain gauges 16 and 1 described below.
6 is 10% larger than the width W ₁₆ (W ₁₄ ≧ 1.1
W ₁₆ ) is preferable. The reason for this is to reduce the influence of the presence of the inner side surfaces 17, 17 of the groove 14 on the measured values of the strain gauges 16, 16. Further, the distance D ₁ between the outer ring raceway 12 and the bottom surface 15 of the concave groove 14 is 50% or more of the distance D ₂ between the outer ring raceway 12 and the outer peripheral surface of the outer ring 11 (D
_It is preferable that ₂ > D ₁ ≧ 0.5D ₂ ). This is because the distance D between the outer ring raceway 12 and the bottom surface 15 of the groove 14 is
_{This is because if 1} is too small, the rigidity of the outer ring 11 is too low, which adversely affects the measurement accuracy, and if it is significant, the outer ring 11 may be damaged during (measuring) work.

A plurality of strain gauges 16, 16 are attached to the bottom surface 15 of the concave groove 14 as described above at equal intervals in the circumferential direction. Then, the detection signals of the strain gauges 16 and 16 are input to a controller (not shown). This controller has an arithmetic unit, and this arithmetic unit uses the strain gauges 1 described above.
Based on the detection signals of 6 and 16, the load applied to the radial ball bearing incorporating the outer ring 11 is calculated.

The outer ring 11 is elastically deformed by the radial load applied to the radial ball bearing during the measurement work by the bearing load measuring apparatus of the present invention configured as described above. And
This elastic deformation amount is detected by a plurality of strain gauges 16 and 16 attached to the bottom surface 15 of the groove 14. Then, the arithmetic unit incorporated in the controller calculates the load applied to the radial ball bearing. Particularly, in the case of the bearing load measuring apparatus of the present invention, the concave groove 14 for attaching the strain gauges 16, 16 is formed on the outer peripheral surface of the outer ring 11 over the entire circumference in parallel with the outer ring raceway 12. Therefore, the presence of the groove 14 has little influence on the elastic deformation of the outer ring 11. That is, even if the rigidity of the outer ring 11 is reduced due to the formation of the concave groove 14, this reduction in rigidity occurs uniformly over the entire circumference.
Therefore, by forming the groove 14, stress concentration does not occur in a part in the circumferential direction. In other words, since the groove 14 does not locally change the rigidity of the outer ring 11 in the circumferential direction, it is possible to accurately obtain the distribution of the load applied to the outer ring 11, and the highly reliable measurement result can be obtained. Can be obtained.

Next, an experiment in which the load actually applied to the radial ball bearing is measured by the bearing load measuring device shown in FIGS. For the experiment, the applicant company made a model number 6206 (outer diameter = 62 mm, inner diameter = 30 mm,
A deep groove type ball bearing having a width of 16 mm) was used. Strain gauges 16 are attached at 13 positions, which are expected to be in the load zone, in a part of the concave groove 14 formed on the outer peripheral surface of the outer ring 11 which constitutes such a radial ball bearing, and the measurement of each strain gauge 16 is performed. From the value, the radial load applied to the portion was measured.
The shape and size of the concave groove 14 are as shown in FIG.
The radial load was a static load of 1000 kgf. The measurement results and calculated values are shown in FIG.

In FIG. 4, the solid line α indicates the strain gauges 16, 1
6 shows the measured value, and the broken line β shows the calculated value. As is apparent from FIG. 4, the measured value by the bearing load measuring device of the present invention is in good agreement with the calculated value. From this fact, it can be seen that the bearing load measuring device of the present invention can be used to measure the load actually applied to the bearing.

The bearing load measuring device of the present invention is not limited to the case where the radial load applied to the outer ring 11 of the radial ball bearing is measured as described above, but the load applied to the bearing rings of various bearings including slide bearings is measured. Can be used to measure. For example,
As shown in FIG. 5 showing the second embodiment, a groove 14 is formed in the central portion of the inner peripheral surface of the inner ring 18 in the axial direction over the entire circumference, and a strain gauge 16 is formed on the bottom surface 15 of the groove 14. If 16 is attached, the radial load applied to this inner ring 18 can be measured.
Further, as shown in FIG. 6, if a groove 14 is formed on one surface in the axial direction of the thrust bearing ring 19 over the entire circumference and strain gauges 16, 16 are attached to the bottom surface 15 of the groove 14, The thrust load applied to the thrust bearing ring 19 can be measured. still,
In any case, the concave groove 14 is formed and the strain gauges 16 and 1
The bearing ring to which 6 is attached is preferably a so-called fixed ring that does not rotate during use. This is the strain gauge 1
This is because the detection signals of 6 and 16 can be easily taken out without deterioration. That is, when a strain gauge is attached to the rotating wheel that rotates during use, a slip ring is required to take out the detection signal of this strain gauge, and the detection signal easily deteriorates, making it difficult to perform accurate measurement. . Of course, the wiring for signal extraction becomes very complicated.

[0016]

Since the load measuring device for a bearing of the present invention is constructed and operates as described above, the following effects can be obtained. Since the measurement can be performed in a state close to the original shape of the rolling bearing, it is possible to obtain an accurate measurement result that matches the actual use state. 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. Since the work of forming the concave groove is easy, the cost does not increase and the bearing can be used as it is as a general bearing. Therefore, it is possible to realize a compact and inexpensive load measuring unit.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an outer ring showing a first embodiment of a measuring apparatus of the present invention.

FIG. 2 is a partially cutaway perspective view showing a part of the outer ring in an enlarged manner.

FIG. 3 is a partial cross-sectional view of the outer ring.

FIG. 4 is a graph showing measurement results and calculation results.

FIG. 5 is a partial cutaway perspective view of the inner ring showing the second embodiment of the measuring apparatus of the present invention.

FIG. 6 is a partially cutaway perspective view of a thrust bearing ring showing the third embodiment.

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 Outer ring 12 Outer ring raceway 13 Ball 14 Recessed groove 15 Bottom surface 16 Strain gauge 17 Inner surface 18 Inner ring 19 Thrust bearing ring 20 Conductor wire

Claims (1)

[Claims] 1. A load measuring device for a bearing, which measures a load acting on a bearing including a bearing ring having a raceway on one surface, wherein the bearing ring is parallel to the entire other surface of the bearing ring. For a bearing including a groove formed in the groove, at least one strain gauge attached to the bottom surface of the groove, and a calculator that calculates the load applied to the bearing based on the detection signal of the strain gauge. Load measuring device.