JPS581735B2 - Oil seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the axial contact pressure distribution of a seal, which simplifies the measurement work.

Conventional measurements of this type of force distribution, taking an oil seal as an example of a measurement target, are carried out by a photoelastic experimental method that uses a model with the same cross-sectional shape as the oil seal to be measured, or by an electrical connection to the pressure detection device. The contact pressure that occurs when the oil seal rib slides on the shaft is detected by a force detection pin that is raised up from a plate spring with a strain gauge connected to the shaft, and whose tip is positioned approximately flush with the shaft surface. The current situation is that it is being detected.

However, in the case of the above-mentioned former photoelasticity experimental method, the preparation of an oil seal model and the analysis after measuring the stress of the model are complicated, and this type of measurement cannot be performed on the actual oil seal.

In addition, recent oil seals have a very narrow lip contact width, so in the latter case the pressure detection pin itself has a smaller diameter, causing the phenomenon of biting into the oil seal lip surface. It was difficult to make accurate measurements due to the occurrence of

The present invention has been made in view of the above points, and its purpose is to eliminate the above-mentioned conventional defects at once by making it possible to easily and accurately measure the axial contact force distribution of a seal at any time. It is something.

Below, an embodiment of the present invention in which an oil seal is a measuring object will be explained based on the drawings.A cylindrical shaft 1 has guide grooves 2 formed at necessary locations, and the guide grooves 2 have an axially operating slider. The tip of the micrometer head 3 is exposed.

Furthermore, a sliding body 4 that is movable in the axial direction is fitted in the guide groove 2, and when this sliding body 4 is pulled by a radial spring 5 on the bottom surface C of the guide groove 2, an axial spring 6
The tip of the micrometer head 3 is pressed against the tip surface of the micrometer head 3.

Furthermore, an annular groove T having a constant opening width in the axial direction is bored in the circumferential direction of the sliding body 4, and a pressure receiving body 8 is formed inside the annular groove T.
is fitted.

This pressure-receiving body 8 has an arc shape having a constant width in the axial direction, similar to the opening width of the annular groove 1, and has a piezoelectric element located between the inner bottom wall of the annular groove 5 and the inner circumferential surface of the arc. A body 9 is attached.

This piezoelectric body 9 is made of barium titanate or the like, and is polarized after metal plating on the top and bottom surfaces.A voltage amplifier (not shown) is connected to the lead wire 10 connected to the metal plating surface. electrically connected to

The pressure-receiving body 8, which is thus equipped with the piezoelectric body 9 and fitted into the annular groove 7 of the sliding body 4, is arranged such that its surface is substantially flush with the sliding body 4 during normal times.

Then, the lip portion 12 of the oil seal 11 inserted into the shaft 1 is placed in contact with the pressure receiving body 8, and from this state, the micrometer head 3 is operated to move the sliding body 4 forward in the axial direction (to the right in the figure). Or move it backward (to the left in the figure) so that part of the lip part 12 comes into contact with the surface of the sliding body 4, and the remaining part contacts the pressure receiving body 8.
By gradually changing the ratio of contact between the surface of the pressure receiving body 8 and the surface of the sliding body 4, the load on the pressure receiving body 8 by the lip portion 12 changes. The change in the contact width between the lip portion 12 and the pressure receiving body 8 obtained by reading the meter head 3 is correlated with the value of the load on the lip portion 12 plotted by the voltage amplifier via the piezoelectric body 9, and analyzed. By doing so, the axial contact pressure distribution of the lip portion 12 is measured.

The present invention is as described above, and since the pressure receiving body provided with the piezoelectric body on the inner circumferential surface is simply brought into contact with the sliding contact surface of the seal to be measured and the pressure receiving body is moved in the axial direction, it is different from the conventional method. The contact pressure distribution in the axial direction of the actual seal to be measured can be easily and skillfully measured at any time without absolutely requiring a seal model to be measured as in the case of the photoelastic experimental method. Since the bottle has an arc shape with a constant width in the axial direction, unlike the conventional pressure detection bottle method, measurement accuracy may be affected by narrow lip surfaces or minute scratches on the lip surface. Therefore, the average axial contact pressure distribution can be reliably measured.

[Brief explanation of the drawing]

The drawing is an explanatory cross-sectional view of a pressure detection device showing an embodiment of the present invention. 8...Pressure receiving body, 9...Piezoelectric body, 11.
...Oil seal, 12...Lip.

Claims (1)

[Claims] 1 The sliding body 4 is provided with a circular arc-shaped surface and is arranged to be movable in the axial direction, and the sliding body 4 is equipped with a circular cedar-shaped surface having a constant width in the axial direction, and a piezoelectric body 9 is attached to the inner circumferential side. A pressure receiving body 8, which is mounted on a radially movable cylinder and whose arcuate surface is kept at the same level as the arcuate surface of the sliding body 4, is brought into contact with the circumferential surface of the contact portion 12 of the seal to be measured. By moving the sliding body 4 in the axial direction, a change in the contact ratio of the contact portion 12 of the seal with the pressure receiving body 8 and the sliding body 4, and a change in the load due to the contact portion 12 of the seal with respect to the pressure receiving body 8. A method for measuring axial contact pressure distribution of a seal, characterized in that it corresponds to the following.