RU192272U1 - A STAND FOR MEASURING THE INERTIES OF AGRICULTURAL MACHINES - Google Patents

Abstract

The utility model relates to the experimental determination of the moments of inertia of agricultural machines. The technical result of the utility model is the possibility of studying mounted and semi-mounted agricultural machines and increase the accuracy of measurements. The technical result is achieved by the fact that the stand for measuring the moments of inertia of agricultural machines contains a hinge support and a measuring device. The hinged support is made in the form of an axis with a device for mounting the object under study, rotating in two bearing bearings, resting on a lifting device in the form of jacks, sliding in the grooves of vertical racks rigidly mounted on the base frame, and the measuring device consists of a stationary flat disk and pressed to associated with the cargo axis of the movable disk with a slot and mounted above it with a laser computer mouse connected to a laptop, while the device is configured to suspend my object to an elastic suspension. 2 ill.

Description

A known stand for measuring moments of inertia, which is a frame with four vertical springs, on which the product is installed using special clamps. In places where the springs are attached to the clamps, displacement sensors are located that measure the deformation of the springs. To prevent these points from moving horizontally, guide bushings are provided in the stand design. Thus, the movement of the product is possible only in three degrees of freedom [Bogdanov V.V., Volobuev B.C. and others. A complex for measuring masses and moments of inertia of engineering products. // Measuring equipment No. 2, 2002, p. 37-39.]

Prior to the measurement, a force is applied to the springs, which is then immediately removed and the system begins to make free oscillations in three degrees of freedom. As a result of digital processing of the signals of each of the sensors, the frequencies and amplitudes of oscillations used to determine the moments of inertia of the product are found. To obtain three axial moments of inertia, it is necessary to rotate the product 90 ° around the longitudinal axis.

A significant drawback of this stand is the lack of measurement accuracy due to possible differences in the stiffness coefficient of the four springs.

- Inability to install mounted and trailed agricultural machines.

The closest analogue to the claimed one is a stand for determining the moments of inertia of transport objects [Bashkardin A.G., Kravchenko P.A., Stepanov V.G. A stand for determining the moments of inertia of transport objects. USSR copyright certificate No. 868424, cl. G01M 17/06, G01H 7/00, 1981], comprising a loading platform supported by four supports, two of which are made in the form of elastic elements

The disadvantages of this invention are:

- the need for a separate determination of the moment of inertia of an empty platform and with an object installed on it;

- decrease in measurement accuracy due to the need for selection and control of elastic supports with the same stiffness coefficient.

- Inability to determine the moments of inertia of mounted and semi-mounted agricultural machines.

The purpose of the utility model is to gain the opportunity to study mounted and semi-mounted agricultural machines and to increase the accuracy of measurements. This goal is achieved by using one hinge and one elastic element instead of four, there is a computer-associated vibration fixation system, and the bench device does not require support wheels for the machine under study.

In FIG. 1 shows a stand with an agricultural machine mounted on it (semi-mounted sprayer), side view; in FIG. 2 is a cross section of a measuring device in a vertical plane along the load axis of the stand.

The stand (Fig. 1) contains a cargo axis 1 with a fastening device for the agricultural machine under study (not shown), rotating in two bearing bearings 2, supported by a lifting device 3 in the form of jacks, sliding in the grooves of the vertical posts 4, rigidly mounted on the base frame 5, a measuring device.

The measuring device (Fig. 2) consists of a fixed flat disk 6 and a movable disk 7 rigidly connected to the load axis 1 of the movable disk 7 with a slot 8, and a laser computer mouse 9 connected to a laptop (not shown) fixed above it.

The work of the stand is as follows.

To determine the moment of inertia of the agricultural machine relative to the main longitudinal axis, the machine is mounted on a stand, as shown in FIG. 1. The machine frame is attached to the load axis 1 of the stand parallel to its longitudinal axis of symmetry at a technically convenient distance b _c from the center of mass horizontally and z _c - vertically.

On the opposite side, the machine is suspended from an external elastic suspension (not shown), and the axis of the stand is lifted by jacks 3 by 0.3 m. By giving the machine a horizontal position with an elastic suspension, the suspended side of the machine is rejected 0.1 m from the horizontal position down and sharply let go. The machine, together with the cargo shaft and the movable disk 7 coaxially attached to it, will begin to perform damped angular oscillations, which are read through the slot 8 by the computer mouse 9 and transferred to the laptop, where the oscillation period is determined.

The well-known formula determines the moment of inertia of the sprayer relative to the axis of rotation of the support shaft.

where: T - period of oscillation, s;

k _ST is the stiffness coefficient of the elastic suspension, N / m;

- расстояние от точки подвеса до оси вращения машины по горизонтали, м.

- distance from the suspension point to the horizontal axis of rotation of the machine, m

Then, according to the well-known formula, the moment of inertia is recalculated relative to the main longitudinal axis of the machine OX

where M is the mass of the machine, kg;

b _c , z _c are the distances indicated in FIG. 1, in meters.

According to the above methodology, the moment of inertia of the machine relative to the main axes is determined for different masses of consumable working material. According to the data obtained, it is easy to formalize the unsteady nature of the moment of inertia of the unit as the working material (seeds, fertilizers, working fluid, etc.) is consumed.

Information sources:

1. Bogdanov V.V., Volobuev B.C. and others. A complex for measuring masses and moments of inertia of engineering products. // Measuring equipment No. 2, 2002, p. 37-39.

2. Bashkardin A.G., Kravchenko P.A., Stepanov V.G. A stand for determining the moments of inertia of transport objects. USSR copyright certificate No. 868424, cl. G01M 17/06, G01H 7/00, 1981.

Claims (1)

A stand for measuring the moments of inertia of agricultural machines, comprising a hinge support and a measuring device, characterized in that the hinge support is made in the form of an axis with a mounting device for the object under study, rotating in two bearing bearings, supported by a lifting device in the form of jacks, sliding in the grooves of vertical racks rigidly mounted on the base frame, and the measuring device consists of a fixed flat disk and pressed to it, connected with the cargo axis of the movable disk with a slot and fixed above the laser computer mouse connected to the laptop, the apparatus is adapted to suspension of the test object to the resilient suspension.

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