JP3624965B2 - Bearing device with load sensor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a bearing device with a load sensor.
[0002]
[Prior art]
Conventionally, in order to directly detect a radial load applied to a rotating shaft or a bearing thereof, there is one in which a load sensor is incorporated in a rolling bearing. In this case, a strain gauge is generally used as the load sensor (see, for example, Japanese Utility Model Laid-Open Nos. 6-47833 and 6-32734).
[0003]
The strain gauge is flat, does not require a large installation space, and can be attached so as to be attached to the bearing ring of the rolling bearing. Therefore, the bearing device provided with this strain gauge is gathered into an outer shape that is the same as that of a general rolling bearing, has few restrictions on the place of use, and is versatile.
[0004]
[Problems to be solved by the invention]
By the way, the strain gauge requires an additional circuit such as signal amplification and wiring, and in the bearing device provided with the strain gauge, the configuration other than the sensor body is complicated.
[0005]
On the other hand, what used the load cell as a load sensor is considered. The bearing device provided with this load cell does not require troublesome wiring and is easy to manufacture. In this case, the outer shape of the device is a shape in which the load cell protrudes from the rolling bearing. However, if the place of use is determined in advance, there is no need to stick to the entire outer shape and there is no problem. However, the load cell is expensive, and the cost of the entire apparatus is greatly increased.
[0006]
In addition, in a bearing device that simply combines a load cell and a rolling bearing, it is necessary to support the load cell in a stationary manner against deformation or displacement caused by the load of the rolling bearing. It must be installed, and it is troublesome to attach it to the place of use.
[0007]
Therefore, the present invention uses a rotary potentiometer as a load sensor, and by incorporating the potentiometer support member and the bearing into an integral unit, the load sensor can be easily manufactured and attached to the place of use. An object is to provide a bearing device.
[0008]
[Means for Solving the Problems]
In the bearing device with a load sensor of the present invention, an outer cylinder is provided on an outer ring outer periphery of a rolling bearing that is an inner ring rotation via an elastic ring, and a rotary potentiometer is attached to the outer cylinder. A hole penetrating in the radial direction is provided at a predetermined position on the circumference of the ring, and a contact is provided in the hole so as to be capable of radial displacement while being in contact with the outer ring, and the contact is provided with the potentiometer. Are coupled to each other through a linear / rotary conversion mechanism.
[0009]
[Action]
When a radial load is applied to the rolling bearing, the rolling bearing is displaced in one radial direction against the elastic force of the elastic ring in the outer cylinder, and the contact that contacts this is displaced radially outward. This linear displacement of the contact is converted into rotation by the linear / rotation conversion mechanism and transmitted to the input shaft of the potentiometer. An electric signal corresponding to the displacement of the rolling bearing is output from the potentiometer.
[0010]
【Example】
The details of the present invention will be described below based on the embodiment shown in FIGS. 1 to 3 relate to one embodiment of the present invention, FIG. 1 is a longitudinal side view of a bearing device with a load sensor, FIG. 2 is a front view thereof, and FIG. 3 is an exploded perspective view of a main part.
[0011]
In these drawings, reference numeral 1 denotes a rolling bearing used as an inner ring rotating type, 1a being an inner ring, 1b being an outer ring, and 1c being a rolling element such as a ball. An elastic ring 2 is fitted on the outer circumference of the outer ring 1 b that is a fixed ring, and a metal outer cylinder 3 is fitted on the outer circumference of the elastic ring 2.
[0012]
The elastic ring 2 and the outer cylinder 3 have holes 2h and 3h (illustrated in FIG. 3) penetrating in the radial direction at the same angular position, for example, the lowest position, and the outer diameter side openings of these holes 2h and 3h. Around the portion, a flat mounting seat 4 is formed on the outer periphery of the outer cylinder 3.
[0013]
Reference numeral 5 denotes a rotary type potentiometer as a load sensor, which incorporates a return spring. The potentiometer 5 is attached to the mounting seat 4 of the outer cylinder 3 with a screw 7 via the mounting bracket 6 so that the input shaft 5s is inserted into the hole 3h of the outer cylinder 3.
[0014]
As shown in FIG. 3, the mounting bracket 6 is integrally formed with a guide tube 6t at the center. The guide cylinder 6t has a non-circular cross section according to the shape of the hole 2h of the elastic ring 2, and in the illustrated example, the guide cylinder 6t is formed in a shape with two notches in the diameter direction of the circle. The elastic ring 2 and the outer cylinder 3 is inserted into the holes 2h, 3h. A contact 8 is inserted into the guide tube 6t so as to be non-rotatable and slidable only in the radial direction.
[0015]
The contact 8 comes into contact with the outer peripheral surface of the outer ring 1b of the rolling bearing 1, has an outer shape corresponding to the guide cylinder 6t, and has a hole 8h at the center in the length direction, and a potentiometer in the hole 8h. Five input shafts 5s are inserted. The hole 8h of the contact 8 and the input shaft 5s have a torsion spline that is screwed together, and the displacement in the radial direction of the contact 8 is converted into the rotation of the input shaft 5s by the screwing of the torsion splines. It has come to be. That is, the contact 8 and the input shaft 5s constitute a linear / rotational conversion mechanism composed of a feed screw. In this case, it is preferable that the angle of the torsion spline formed on the contact 8 and the input shaft 5s is set to a value at which a conversion magnification as large as possible can be obtained without hindering the sliding displacement of the contact 8, for example 45 °.
[0016]
By the way, the above-mentioned elastic ring 2 is formed of a synthetic resin such as 66 nylon or rubber not containing reinforcing fibers. The outer cylinder 3 is preferably formed of a steel material such as JIS standard SUJ2, the mounting bracket 6 is a JIS standard SPCC, and the contact 8 is a steel material such as JIS standard SCM420H carburized and quenched.
[0017]
Next, the operation will be described. First, when a radial load is applied to the rolling bearing 1, the rolling bearing 1 is deformed in one direction in the radial direction against the elastic force of the elastic ring 2 in the outer cylinder 3, and the contact 8 in contact with the radial bearing 8 has a diameter. It can be displaced by sliding outward. When the contact 8 is slid, the input shaft 5s of the potentiometer 5 is rotated by the torsion spline. Thus, when the input shaft 5s is rotated, the potentiometer 5 outputs an electrical signal corresponding to the radial displacement of the rolling bearing 1, and can detect the radial load from this output signal.
[0018]
In such an operation, the displacement of the contact 8 with respect to the radial load is determined by the material of the elastic ring 2 and the thickness in the radial direction, and the rotation angle of the input shaft 5s with respect to the displacement of the contact 8 is determined by the contact. 8 and the specifications of the torsion spline provided on the input shaft 5s.
[0019]
Specifically, for example, when the elastic ring 2 is made of 66 nylon containing no reinforcing fiber and the thickness in the radial direction is 2.5 mm, the displacement amount of the contact 8 is 0.00 when the radial load is 20 kgf. When 15 mm and 50 kgf, it is 0.38 mm, and when 100 kgf, it is 0.76 mm.
[0020]
The angle of the torsion spline provided on the contact 8 and the input shaft 5s is 45 °, the lead is 9.4 mm, the module is 0.5, the number of teeth is 6, and the fractional right angle pressure angle is 20 °. When the large diameter and the small diameter of the input shaft 5s are 4.0 mm and 3.0 mm, respectively, and the large diameter and the small diameter of the input shaft 5s are 4.0 mm and 2.8 mm, respectively, the rotation angle of the input shaft 5s is When the displacement is 0.15 mm, it is 5.7 °, when the displacement is 0.38 mm, it is 14.6 °, and when the displacement is 0.76 mm, it is 29.1 °.
[0021]
Thus, the rotation angle of the input shaft 5s can be set to a value sufficient for measurement by the rotary potentiometer 5.
[0022]
By the way, the elastic ring 2 inserts the rolling bearing 1 and the outer cylinder 3 into the mold, and injects the material of the elastic ring 2 between the jigs at the attachment portions of the contactor 8 and the input shaft 5s. It can be formed by injection molding.
[0023]
In the above embodiment, the contact 8 and the input shaft 5s of the potentiometer 5 are interlocked and connected via a torsion spline. However, both of them need only be interlocked and connected via an appropriate linear / rotary conversion mechanism. For example, the linkage may be linked by a linear / rotary conversion mechanism including a rack and a pinion. When this rack / pinion mechanism is used, it is necessary to mount the potentiometer in a direction in which the input shaft intersects the contactor at a right angle with the contactor serving as a rack.
[0024]
【The invention's effect】
The present invention detects the radial load by converting the radial displacement of the rolling bearing due to the radial load into the rotation of the input shaft of the rotary potentiometer. Therefore, it is possible to manufacture easily at low cost because it uses a potentiometer that is much cheaper than a load cell.
[0025]
In addition, since the outer cylinder, which is a potentiometer support member, is integrated with the rolling bearing as a unit, the entire device can be integrated as a single unit at the point of use, and the rolling bearing and load sensor are attached separately. There is no need, and it does not take time to attach to the place of use.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a bearing device with a load sensor according to an embodiment of the present invention. FIG. 2 is a front view of the device. FIG. 3 is an exploded perspective view of essential parts of the device.
DESCRIPTION OF SYMBOLS 1 Rolling bearing 1b Outer ring 2 Elastic ring 3 Outer cylinder 5 Potentiometer 5s Input shaft 8 Contact

Claims (1)

An outer cylinder is provided on the outer ring outer periphery of the rolling bearing that is an inner ring rotation via an elastic ring, and a rotary potentiometer is attached to the outer cylinder.
Wherein the outer cylinder and holes penetrating in the radial direction in the circumferential position of the elastic ring provided with contacts is provided radially displaceable state abutting state with respect to the outer ring in the hole, the A bearing device with a load sensor, wherein the contact is linked and connected to the input shaft of the potentiometer via a linear / rotational conversion mechanism.

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