FI124566B - Arrangement for measuring the radial forces of the bearing - Google Patents

Description

Arrangement for measuring the radial forces of the bearing

Background of the Invention

The invention relates to an arrangement for measuring the radial forces of a bearing, which comprises a sensor body mounted adjacent the bearing housing 5 of the device, in a space formed by the bearing forces of the bearing in the bearing housing such that it is subjected to bearing radial forces; a radial force transducer mounted on the sensor body and located in or close to a plane passing substantially through the radial plane of the bearing; and means for transferring the measurement results provided by the measuring sensor outside the sensor body, wherein the bearing periphery is in direct contact with the sensor body.

The arrangement in question is intended to measure, for example, the radial forces of the gearbox shaft bearing in the chain hoist. Particularly in chain hoists which exhibit oscillation due to the angle of the sprocket 15 and thus also the dynamics of the bearing forces, the bearing force measurement data can be used to control the speed of rotation of the hoisting motor, for example by means of a frequency converter. As a result, the overall dynamics of the hoist can be significantly reduced, thereby improving the comfort and safety of the hoist and extending its life.

20 This arrangement, in principle, is also applicable to other types of gearboxes and can also be used to check the condition of the bearing and to detect damage. Bearing radial force measurement data can also be used for coarse load lifting.

It is well known in the art to position a 25 tubular sensor body with a strain gauge sensor in a circular bore of the gearbox body, which is formed close to the bearing housing so that a thin base is left between the bearing housing and the sensor housing for short contact with the bearing outer ring. Such a design has the disadvantage of its construction that the bore for the sensor body must be tight so that, for example, in certain structures, the gear oil does not drain. 30 r and drilling. Such a tight fit between the bore of the sensor body and the gearbox body results in difficulty of mounting the sensor body c0. The installation requires a higher force that can damage the sensor body and ° sensor. In addition, the sensor generates a difficult-to-predict bias, which must therefore be eliminated by calibrating each sensor separately after installation. If the adapter was loose, that is, a slider, the sensor would not detect any small loads at all. Another disadvantage of the tight fit is that the different thermal expansion of the materials of the bearing, bearing housing and sensor housing 2 can cause non-linearity in the measurement result, which is difficult to compensate.

The prior art described above is represented, inter alia, by WO 2006/018276 A1.

5 Summary of the Invention

It is an object of the invention to provide a new arrangement for measuring the radial forces of the bearing so that the above problems can be solved. This object is achieved by an arrangement according to the invention, characterized in that the bore for the bearing housing and the bore for the sensor housing 10 intersect, whereby the sensor body is provided with a recess corresponding to the shape of the outer periphery of the bearing.

By simply omitting the previous socket between the bore for the sensor body and the bearing housing, all the problems described above can be eliminated.

Measurement accuracy and efficiency are improved by increasing the contact area between the outer surface of the bearing and the sensor body, so that even small radial forces or changes thereof can be easily detected.

It is also particularly advantageous that the sensor body is weakened in the region adjacent to the mit-20 sensor to ensure a measurable deformation in this region of the sensor body. This attenuation can be accomplished in a number of different ways, as will be apparent from the subsequent description of the invention.

Further advantageous details of the invention are set forth in the claims and in the specification.

BRIEF DESCRIPTION OF THE DRAWINGS δ ™ The invention will now be described in greater detail by means of preferred embodiments o with reference to the accompanying drawings, in which: Fig. 1 illustrates a transducer g of the invention in a simplified longitudinal section;

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Figure 2 shows the sensor assembly of Figure 1 as viewed from the inside of the gearbox body in the direction of the bearing axis;

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Fig. 3 is a view showing the sensor assembly shown in Figs. 1 in a differently separated and similar section as in Fig. 1; Figure 4 shows a view in Figure 3 of an end remaining inside the gearbox body without the seal shown in Figure 3; Figures 5 and 6 are representations similar to Figures 3 and 4 of an alternative embodiment of a sensor arrangement according to the invention; Figures 7 and 8 also show representations similar to Figures 3 and 4 in another alternative embodiment of the sensor arrangement according to the invention; Fig. 9 shows another embodiment of the sensor assembly according to the invention in longitudinal section.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figures 1 and 2, they show part of a gearbox body 1, 10 having a bearing housing 2 and a bearing 3 disposed therein, since the gearbox shaft supported on the bearing 3 is not shown, since the gearbox structure itself is not essential to the invention.

In the direction of action of the radial forces F of the bearing 3, i.e. in this case above the bearing 3, a space 4 is arranged on the body 1 with a 15 sensor body 5. The space 4 is formed so that the sensor body 5 is exposed to the radial forces F of the bearing 3. and opposite reaction forces of the sensor body 5. Attached to the transducer body 5 is a radial force measuring transducer 6 located in the transducer body 5 substantially in a plane passing through the radial plane of the bearing 3, i.e. directly in the direction of action of the radial forces 20. In turn, a measuring cable 6 is attached to the measuring sensor 6, which passes through the sensor body 5 outside the gearbox and forwards the results provided by the measuring sensor 6 for further processing.

The measuring transducer 6 is typically a strain gauge transducer, which in this case receives a response to the compressive forces (see in particular Fig. 4). Other sufficiently sensitive sensors for measuring compression or tensile forces may also be considered.

* 3- £ A shear force sensor is also possible when, for example, a part of the sensor body that undergoes deformation is shaped such that a shear co 9 is applied to it. The sensor shown in Figures 1-4 is disposed in a recess 8 formed at the end of the sensor body 5.

| The sensor body 5 is substantially in the form of a rotary piece and the space 4 therefor is thus a cylindrical bore having a diameter corresponding to the diameter of the sensor body 5 and having a central axis so that the central axis of the sensor body 5 is parallel to the is that the outer circumference 9 of the bearing 3 is in direct contact with the sensor body 5. In this example, for this purpose, the bore for the bearing housing 2 and the bore for the sensor body 5 are

The bore of the bore 4 intersects with each other, whereby a recess 10 corresponding to the shape of the outer periphery 9 of the bearing 3 is formed in the sensor body 5 at a position opposite the outer circumference 9 of the bearing 3 in the cutting area of said bores.

Preferably, the material of the sensor body 5 is the same as the material of the surrounding body 5 at least around the sensor body 5 or the material properties of the material are substantially the same as the material of the surrounding body 1 at least around the sensor body 5. Preferably, the coefficient of thermal expansion of the material of the sensor body 5 is at most equal to that of the surrounding body material 1.

10 so that the bearing receiving and measuring point of the sensor body 5 can experience sufficient deformation without too much resistance to the deformation of the other area of the sensor body 5, the sensor body 5 is weakened in the area near the measuring sensor 6. This weakening is effected by a recess or bore 11 in the sensor body 5 and a throat 15 in the outer periphery of the sensor body 5. The part 13 of the sensor body 5 that comes into contact with the outer periphery 9 of the bearing 3 is further lightened on both sides (see FIG. such that this side 13 forms straight side walls 14.

At the end of the sensor body 5, which faces the wall 15 of the body 1 in space 4, there is a resilient seal 16 which is pressed against the wall 15, thereby providing a seal which protects the sensor 6 from the lubricant used in the gearbox. On the opposite side of the sensor body 5 there is a second seal 17 which is pressed against the outer edge of the space 4 of the body 1 by means of the mounting flange 18 of the sensor body 5 preventing the lubricant from leaking from the gap between the sensor body 5.

The transducer body 5 with the transducer 6 is mounted either first in the gearbox run-25 size 1 or when the gearbox is otherwise assembled. The tolerances of the sensor body 5 and the space 4 intended for it are chosen so that the installation can be carried out without high installation forces. In practice, a slider that is allowed to be left is selected

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a slight clearance between the sensor body 5 and the space 4. This clearance ensures that no prestress is generated on the sensor body 4. On the other hand, this clearance can cause a slight displacement of the bearing end 30 and the shaft below it, and thereby the contact current | between the pinion on the shaft. However, this error is so small ^ that it can be tolerated. The clearance in question also compensates for the potential of the materials used in construction g (body 1, bearing 3, material of sensor body 5)

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Dimensional changes due to different thermal expansion coefficients which could result in undesirable biasing of the sensor body 5 and hence an incorrect force measurement result. It is preferable to use a bearing having a thick outer ring as a bearing. This is appropriate because the scrolling elements passing by the sensor also exert a force on the sensor and thus add extra hard-to-filter peaks to the signal from the sensor.

The sensor body 50 shown in Figures 5 and 6 differs from the sensor body 5 shown in Figures 1-4 5 only in that the sensor body 50 is attenuated in the region near the measuring sensor 6. This weakening is effected by means of material removal or recess 110 made to the sensor body 50 below it, which extends over a substantial portion of the sensor body 50, past its center line. The part 130 of the sensor body 50 which comes into contact with the outer periphery 9 of the wafer 10 is further lightened on both sides thereof (see Fig. 4) such that side recesses 140 are formed in this part 130. These side recesses may also be used under the guidance of.

Figures 7 and 8 show a sensor body 150 which is two-piece comprising a main body 151 and a contact part 152 that contacts the outer periphery 9 of the bearing 3 15 and is secured to the main body 151 by axial bolts 153. This also allows the sensor 6 to be positioned 6 is now shown positioned at the outermost end of the contact portion 152.

Figure 9 further illustrates a possible simple implementation of the sensor body 20,250.

The above description of the invention is intended only to illustrate the basic idea of the invention. Thus, one of ordinary skill in the art can modify its details within the scope of the appended claims. Furthermore, it should be noted that the radial forces of the bearing in the bearing housing may affect in other directions than above the bearing, for example, sideways, always depending on the direction in which the load at the other end of the bearing shaft acts. The solution according to the invention may also be possible.

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The list also applies to other applications where the desired compression, tensile or shear forces or corresponding stresses are measured and monitored.

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Claims (9)

An arrangement for measuring the radial forces of a bearing, which comprises a sensor body (5; 50; 150; 250) mounted adjacent the bearing (5) of the device 5 in a space formed by the radial forces (F) of the bearing (3) in the bearing housing. (4) being subjected to radial forces of a bearing when operating the device, a radial force measuring transducer (6) attached to the sensor body (5; 50; 150; 250) and located in or close to the radial plane 10 of the bearing (3); means (7) for transferring the measurement results provided by the measuring sensor (6) outside the sensor body (5; 50; 150; 250), wherein the outer periphery (9) of the bearing (3) is in direct contact with the sensor body; the bore (4) of the space (4) for the sensor body (5; 50; 150; 250) intersects one another, whereby the sensor body is formed against the bearing periphery (9). 1a, a recess (10) corresponding to the shape of the outer circumference of the bearing in the cutting area of said bores. Arrangement according to Claim 1, characterized in that the sensor body (5; 50; 150; 250) is substantially in the form of a rotary block, its central axis (A) being substantially parallel to the central axis (B) of the bearing (3). An arrangement according to claim 1 or 2, characterized in that the material of the sensor body (5; 50; 150; 250) is the same or the material has the same material properties as the material of the surrounding device at least around the sensor body. Arrangement according to one of the preceding claims, characterized in that the material of the sensor body (5; 50; 150; 250) has a coefficient of thermal expansion of at most 30% that of the surrounding material of the device. Arrangement according to one of the preceding claims, characterized in that the bearing (3) is fitted in the bearing housing (2) with a loose fitting, COg, so that the bearing can load the sensor body (5; 50; 150; 250). Arrangement according to one of the preceding claims, characterized in that the sensor body (5; 50; 150; 250) is fitted to the device by a sliding adapter. Arrangement according to one of the preceding claims, characterized in that the means for transferring the measurement results provided by the measuring sensor (6) to the outside of the sensor body (5; 50; 150; 250) comprise a wire cable (7) secured to the measuring sensor and routed outside the sensor body. Arrangement according to one of the preceding claims, characterized in that the measuring sensor (6) is a strain gauge sensor. Arrangement according to one of the preceding claims, characterized in that the sensor body (5; 50; 150; 250) is weakened in the area near the measuring sensor 10 (6) to ensure a measurable deformation in this area of the sensor body. 't δ c \ j CD O o X CC CL δ CD o δ CVJ