JPS58100731A - Measuring device for towing resistance - Google Patents

Abstract

PURPOSE:To measure towing resistance where the frictional force of a towing device does not affect a measured value by separating a part for towing a body to be tested and a part for executing a measurement. CONSTITUTION:A towing car 20 moves linearly in a prescribed direction over the surface of water in a water tank. A swing carriage 1 is movable at right angles to the moving direction of the towing car, and a surging carriage 2 is movable in said moving direction. A heaving pole 3 penetrated the surging carriage 2 and is supported movably upwardly and downwardly, and the pole is engaged pivotally with a model ship 4 through a load cell 16 fixed to its lower end. The driving shaft of a torque motor 13 mounted on the swing carriage 1 is wound with one end of a towing cord 14 and the other end is fixed to the surging carriage 2. So that force W corresponding to the resistance R of a body 4 to be tested is obtained, the supply current of the motor 13 is adjusted, obtaining the balance with the resistance of the model ship. The resistance R of the body 4 is measured by the load cell 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a towing resistance measuring device for measuring the resistance of a test model (hereinafter referred to as a test object) such as a ship and marine structure in waves or calm water in a water tank or the like.

Conventionally, resistance measurement of a specimen, particularly resistance measurement in waves, has been carried out using an apparatus as shown in FIG. That is, in FIG. 9, 20 is a towing vehicle that travels in a predetermined direction on a rail laid on the side of the aquarium above the water surface of the aquarium, and 1 is a swooping carriage that is movable in the left-right direction with respect to the towing vehicle 20.

Reference numeral 2 denotes a surging carriage that can move forward and backward with respect to the swinging carriage 1. Reference numeral 3 denotes a heaving ball, the upper part of which passes through the center of the surging carriage 2 and is guided so that it can move up and down (slide) in an almost vertical direction. . The towing point 5 of the specimen 4 is pivoted to the lower end of the heaving ball 6.

Reference numeral 12 is a steering gear mounted on the specimen.

Each of the pair of springs 6 is fixed to the tow wheel 20 at one end and to the swing carriage 1 at the other end.

The towing pulley 7 and the weight boo 98 are supported by bearings fixed to the swooping carriage 1, respectively. 9 is a towing hood, which is wrapped around a towing boo 97 and a weight pulley 8vc as shown in the figure, and one end is attached to the surging carriage 2.
is fixed to the front end, and a weight 10 is suspended from the other end. Reference numeral 11 denotes a spring, one end of which is fixed to the swinging carriage 1 and the other end connected to the weight pulley 8.

In the above configuration, the towing vehicle 20 is moved in a predetermined direction while the two weights 10 are approximately balanced with the resistance R of the specimen 4, and the weight 1 is
Measure the resistance R by weighing 00 weight. In the oblique waves, the specimen 4 tends to move in the left-right direction and drift. On the other hand, the flexible spring 6 provides a restoring force to the swooping carriage 1, and on the other hand, the steering gear 12 is steered by remote control to maintain a predetermined towing direction.

The pulling force is mainly measured by the weight of the 100 weights, but since the 9-weight boo 98 is connected to the flexible spring 11, the 4. Therefore, the movement of the surging carriage 20 in the front and back direction is allowed.

The spring 11 converts the resistance unbalanced by the weight 10 into a displacement for measurement.

However, in this device, almost the entire resistance R of the specimen is measured mainly using a 100-weight WK weight, and therefore, adjustment at the time of measurement requires skill and time.

In addition, when measuring resistance in waves, in the longitudinal direction of the model ship,
Furthermore, since the weights 10 sway due to the lateral movement, there is a drawback that the influence of the inertial force of the 9 weights is mixed into the resistance measurement value. Furthermore, in a device with such a configuration, the frictional force caused by the movement of the surging carriage 2 is directly mixed into the measured value, and it is difficult to completely remove its influence, so there is a limit to the measurement accuracy. There was also.

The present invention eliminates the drawbacks of the conventional apparatus described above, and in order to easily and accurately measure the resistance of a specimen even in waves, the part for towing the specimen and the part for measurement are separated. An attempt is made to provide a device that measures the resistance at a position where the frictional force of the device does not mix into the measured value, and also measures the towing resistance of a specimen by balancing the resistance of the specimen using a torque motor instead of using conventional weights. It is something.

Therefore, the towing resistance measuring device of the present invention uses a towing vehicle that moves linearly in a predetermined direction above the water surface of the aquarium.

A swooping carriage that is mounted on a towing vehicle and is movable in a direction perpendicular to the direction of movement of the towing vehicle along rails laid on the swooping carriage; In the towing resistance measuring device comprising a surging carriage, a specimen which vertically penetrates the surging carriage and is supported so as to be movable in the vertical direction and whose lower end floats on the water surface below the towing vehicle, and a heaving ball pivotally connected, the sway A torque motor fixed to the surging carriage, a traction cord having one end wound around the drive shaft of the torque motor and the other end fixed to the surging carriage, and a traction cord connected below the heaving ball and to the specimen. It is characterized by comprising a load cell provided above the pivot point.

The present invention will be explained in detail below with reference to one drawing.

FIG. 2 is a perspective view of an embodiment of the towing resistance measuring device of the present invention.

In this figure, the same numbers as those in FIG. 1 are the same as those explained in the conventional device, and have the same functions and effects.

In summary, only the configuration that appears in FIG. 1 will be explained.

The torque motor 13 is mounted on the swing carriage 1. A towing hood 1 is attached to the drive shaft of the torque motor 13.
4 is wound around one end, and the other end is fixed to the surging carriage 2.

15 is a spring and one end of it is connected to the surging carriage 2.

The other end is fixed to the swing carriage 1. The heaving ball 3 has a load cell 16 fixed to its lower end.
It is pivotally connected to the model ship 4 via.

It is generally known that the torque applied to the drive shaft of the torque motor 13 is approximately proportional to the supplied current. Since the rotating shaft of the torque motor 13 and the surging carriage 2 are connected by the towing cord 14, the resistance R of the specimen 4 is
The resistance of the model ship 4 can be balanced by adjusting the current supplied to the torque motor 13 so as to obtain a force W corresponding to . Balancing force W caused by excess or deficiency of current supplied to the torque motor 13 and resistance R of the specimen 4
Since the amount of unbalance can be absorbed by the spring 15 that connects the surging carriage 2 and the swinging carriage 1, adjustment of the current supplied to the torque motor 13 is only necessary.

Furthermore, since the resistance R is measured by the load cell 16 as described below, the torque motor 13 only needs to generate a balance force W that roughly corresponds to the resistance R of the model ship 4.

The resistance R of the specimen 4 is measured by a load cell 16 fixed to the lower end of the heaving ball 3. That is, the load cell 16 is arranged at an intermediate position between the heaving ball 3 and the towing point 5 of the specimen 4. Therefore, the influence of the friction between the surging carriage 2 and the swinging carriage 1 or the friction between the brush of the torque motor 13 and the commutator does not enter the load cell 16.

In the conventional method, as shown in FIG. 1, the weight of the 100 weight to balance the resistance of the model ship 4 or the displacement of the spring 11 is related to the measured amount of the resistance R.

The frictional force of the device, such as the frictional force between the surging carriage 2 and the swaying carriage 1, was mixed into the resistance measurement value, but in the device of the present invention, a load cell 16 is used to measure resistance. Since it is separated from the towing resistance balancing section of the specimen 4 and placed in a position where the frictional force of the device is not mixed in, there is an advantage that highly accurate resistance measurement values can be obtained.

In addition, by adopting the torque motor 13 instead of the conventional balance method using the weight 10, the weight 10 can be used during measurement.
Whereas the adjustment required skill and time, the towing force can be easily adjusted by changing the current supplied to the torque motor, and the weight 10 swings with the shaking of the specimen 4.

There is also the advantage that the problem of the influence of the inertial force of the weight 10 being mixed into the resistance measurement value can be eliminated. Furthermore, as a result of separating the towing resistance balancing part of the model ship from the part that measures the resistance,
Another advantage is that the device can be made smaller and lighter because there is more freedom in the installation location and structure of the part that provides the balancing force.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional towing resistance measuring device. Second
The figure is a perspective view showing a towing resistance measuring device as an embodiment of the present invention. 1... Swinging carriage 2... Surging carriage, 3... Heaving ball, 4... Specimen. 5... Towing point of the specimen, 6.11... Spring, 7.
... Towing pulley, 8... Weight pulley, 9... Towing cord. 10... Weight, 12... Steering II, 13... Torque motor, 14... Traction cord, 15... Spring, 1
6...Load cell, 20 tow trucks.

Claims (1)

[Claims] A tow truck that moves linearly in a predetermined direction above the water surface of the aquarium, a swinging carriage that can move along a rail mounted on the tow truck in a direction perpendicular to the direction of movement of the tow truck, and a rail installed on the swinging carriage. A surging carriage that is movable in the direction of movement of the towing vehicle along the surging carriage, and a heaving that is pivotally connected to a specimen that penetrates the surging carriage in the vertical direction and is supported so as to be movable in the vertical direction, with its lower end floating on the water surface below the towing vehicle. A towing resistance measuring device comprising: a torque motor fixed to the swinging carriage; a towing cord having one end wound around a drive shaft of the torque motor and the other end fixed to the surging carriage; A towing resistance measuring device characterized by comprising a load cell interposed below the heaving ball and above a pivot point with the specimen.