JPS6014200Y2 - Measuring device for the load applied to the wing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a device for measuring loads applied to wings of, for example, marine propulsors.

Since marine propellers generally operate in a locally varying wake distribution behind the hull, the thrust and torque generated by the propeller can vary during one rotation.

This change has an important effect on the fatigue strength of the propeller blade, and what threatens the vessel with this change is the fluctuating force or moment generated by the propeller as a whole, which becomes a source of hull vibration.

In order to investigate the strength and excitation force of these propellers, it is effective to measure the thrust and torque of one blade of a model propeller, and for this purpose, a so-called single-blade dynamometer, as illustrated in Figure 1, is used. has been done.

In this device, a blade to be measured 01a is attached inside a propeller boss 02 and supported by a cantilever support member 04, a thrust measurement strain gauge 05 and a torque measurement strain gauge 06 are attached to the support member 04, and the Part 0
By measuring the bending moment of No. 4 at two locations each for thrust and torque, the thrust and torque acting on the blade to be measured 01a are determined.

In the figure, Olb is a wing that is not a measurement light phenomenon, and 03 is a propeller shaft.

However, in this measurement method, the blade is attached to the mounting part 0 of the support member 04.
Displacement is caused by the deflection of the support member 04 with reference point 4a, so if you try to increase the measurement sensitivity by reducing the member dimensions of the strain gauge attachment part of the blade dynamometer, the displacement of the blade will increase and the blade and dynamometer will be displaced. This has the disadvantage that the natural frequency of the combined system becomes low, reducing the accuracy of dynamic measurement of thrust and torque.

The present invention proposes a blade force detection device that can eliminate these drawbacks and increase both the natural frequency that affects measurement accuracy and the measurement sensitivity. This is a device for measuring loads, which consists of a plywood board that forms part of a boss and to which a blade to be measured is fixed, a protrusion formed at both ends of the base plate in the axial direction of the boss, and a plywood board to which the protrusion is fixed. A support integrally formed with a bottom cantilever beam that deforms as the protruding portion is displaced in the boss axial direction and a pair of parallel top cantilever beams that deform as the protruding portion deforms as the boss circumferentially displaces. a member, strain gauges attached to the bottom cantilever and top cantilever of the support member, respectively, and a recess formed in the boss in which the support member and plywood are housed, and the support member is placed in the recess. To provide a device for measuring a load applied to a wing, characterized in that a top cantilever of a member is fixed.

According to the device of the present invention, the supporting member for detecting the amount of strain can be configured to be smaller without increasing the displacement of the blade unlike conventional measuring devices, and the natural frequency is therefore increased, improving measurement accuracy. .

Furthermore, even if the displacement of the blade is small, the curvature of the location where the amount of strain is detected can be increased, so high measurement sensitivity can be achieved.

Next, one embodiment of the device of the present invention will be described based on the drawings.

In FIGS. 2 and 3, reference numeral 1a denotes a propeller blade to be measured, which is erected in a T-shape on the base plate 7 and is fixed integrally with the seventh embodiment.

Projections 8a and 8b are provided at the front and rear of the base plate 7.

Reference numeral 4 denotes a support member that supports the protrusions 8a and 8b, and includes a pair of top cantilevers 4a and a bottom piece so as to measure the thrust acting in the front-rear direction and the force acting in the circumferential direction of the propeller blade 1a. It has a structure in which a support beam 4b is combined, and a strain gauge 5 for measuring thrust force and a strain gauge for measuring circumferential force are attached to these, respectively.

The pair of top cantilever beams 4a have a U-shaped cross section and a protruding portion 8a.
, 8b, and the bottom cantilever 4b is formed to support the protrusions 8a, 8b from below.

The base plate 7 and the two supporting members 4 are arranged such that the supporting member 4 is connected to the protrusion 8.
The ends of the bottom cantilever beam 4b are connected to the base plate 7 by bolts 10 while sandwiching the cantilever beams 4b and 8b, and after being buried in the recess 9 carved in the boss 2, the top cantilever beam 4a The end of the holder is connected to the boss 2 with a bolt 11.

In the figure, 3 is a propeller shaft, and 1b and 1c are propeller blades that are not measured.

After the blade to be measured 1a is attached to the boss 2 in this manner, the propeller blade 1a is rotated, and the amount of strain on each cantilever of the support member 4 is detected to measure the load applied to the propeller blade 1a.

Figures 4 and 5 show that the thrust force T and the circumferential force F are measured on the blade 1.
Fig. 4a and Fig. 5a are exaggerated drawings of the state in which the support member 4 deforms when a force is applied to the support member 4, and Figs. The figure shows cantilever beams 4a and 4b when thrust force T and circumferential force F are applied.
shows a distorted state.

As shown in Figure 4, the strain gauge 5 detects the strain on the bottom cantilever 4b to measure the thrust T, and as shown in Figure 5, the strain on the cantilever 4a can be detected using a strain gauge. The circumferential force F can be measured by

When calculating the torque Q, by assuming the distance γ from the propeller axis to the point of application of the circumferential force F, Q=
It is determined by γF.

Moreover, as a means for detecting the amount of strain, a piezoelectric element or the like can be used in addition to the strain gauge.

In this manner, the present device allows the support member to which the strain gauge is attached to be made smaller without increasing the displacement of the blade 1a as in conventional measuring devices, and therefore the natural frequency is increased, resulting in improved measurement accuracy.

Further, even if the displacement of the propeller blade 1a is small, the curvature of the support member to which the strain gauge is attached can be increased, so high measurement sensitivity can be achieved.

As described above, the device of the present invention can improve both measurement accuracy and measurement sensitivity with a simple device when measuring the load applied to a blade. It is useful for measuring the fluid force generated in the flow.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view showing a conventional load measuring device, Fig. 2 is a perspective view showing an embodiment of the device of the present invention, Fig. 3 is an exploded perspective view of the device described above, and Fig. 4 and FIG. 5 are explanatory diagrams showing the distorted state of the support member 4 when a load is applied to the propeller blade 1 in the above-mentioned device. 1a... Propeller blade to be measured, 2... Propeller boss, 3... Propeller shaft, 4...
・Supporting member, 4a...Top cantilever beam, 4b...
... Bottom cantilever beam, 5 ... Strain gauge for thrust measurement, 6 ... Strain gauge for circumferential force measurement, 7 ... Base plate, 8a, 8b. ...protrusion, 9 ... recess, 10.11 ... bolt.

Claims (1)

[Scope of utility model registration request] This is a device that measures the load applied to the blade to be measured that is attached to the boss and rotates, and is made of plywood that forms part of the boss and to which the blade to be measured is fixed, and is formed on both ends of the boss plate in the axial direction of the boss. a bottom cantilever beam to which the protrusion is fixed and deforms as the protrusion is displaced in the circumferential direction of the boss; and a pair of parallel beams that deform as the protrusion is displaced in the circumferential direction of the boss. A support member integrally formed with a top cantilever, strain gauges affixed to the bottom cantilever and top cantilever of the support member, respectively, and a boss formed on the boss in which the support member and plywood are housed. 1. A measuring device for measuring a load applied to a wing, characterized in that the top cantilever of the support member is fixed to the recess.