LT6584B - Device for detecting sendimentation of magnetoreologie fluids - Google Patents

Abstract

The invention is based on the measurement of the electrical resistance of a magnetorheological fluid when exposed to a magnetic field. The resistance depends on the temperature, the duration of the magnetic field operation of the liquid, the initial particle concentration, the magnetic field strength, and the degree of sedimentation. Self-measuring sensors are used for measuring the resistance, each consisting of two contact plates separated by a 1 mm gap. The device for detecting the sedimentation of a magnetoreological fluid consists of two sensors (2) and (3) embedded in the housing (1), each consisting of two electrically conductive plates separated by a 1 mm gap. These sensors are located in the upper and lower parts of the body, since due to sedimentation, the concentration of particles in different parts of the liquid is uneven. Sensor plates are insulated from the body. The fluid (4) prevents the leakage from sealing (5). The resistivity is measured by a megohmeter located in the programmable logic controller (7), which is connected to the sensors by cables (6).

Description

FIELD OF THE INVENTION

The device belongs to the field of measuring devices and, in particular, is intended for measuring the sedimentation of magnetorheological fluids.

State of the art

There is a known device for detecting sedimentation of a magnetorheological fluid (U.S. Patent Document US20140355645AI, published December 4, 2014). The device uses two elements: a heating element to heat the magnetorheological fluid and a temperature sensor to detect the heat change. Having the dependences of the thermal conductivity of the liquid on the concentration and time of the particles, it is estimated what level of sedimentation has taken place in the liquid at the measured moment. The disadvantages of the device are that its construction is quite complex, as liquid heating equipment is used, and sensors that accurately and reliably measure temperature changes are expensive.

There is a known device for determining the concentration of magnetorheological liquid particles (US patent document US2012164916AI, published on June 28, 2012), thus determining the sedimentation of a liquid. The device uses a coil made of wire, which allows a direct current to flow through an electrical source, thus creating a magnetic field. Another, a measuring coil, exactly the same as that generating the magnetic field, is used to measure the inductance. A special sensor connected to both coils determines their inductance and sends its values to the controller, which controls the apparatus for supplying additional magnetorheological fluid to the system. This system can also be connected to an integrated fluid replenishment module that picks up and mixes the magnetorheological fluid and then returns it back to the system. The disadvantages of the device are that due to its large dimensions, complex construction, as well as the need for an external device to detect sedimentation, it cannot be incorporated into an already developed mechanism without significantly increasing its dimensions. In addition, with an unmixed liquid, it is difficult to determine the exact degree of sedimentation with the aid of this device, since when the liquid is taken into this device, it is already mixed by flowing to the measuring point.

There is a known device for the determination of the sedimentation of a magnetorheological fluid, which uses a wire of electrically conductive material with twisted coils (2016, Kaunas, KTU. Viktorija Mačiukienė. Doctoral dissertation Development and research of a device for the determination of magnetorheological fluid parameters, pp. 101-106). Sedimentation measurement determines the inductance of a coil in a magnetorheological fluid that changes with varying particle concentrations. The degree of sedimentation is determined depending on the measured inductance values. The disadvantages of this device are that the coils wound from the wire of electrically conductive material, which are located inside the structure, take up a lot of space. Also, where there is only a very thin layer of magnetorheological fluid, this device cannot be adapted to measure sedimentation.

Brief description of the invention

This description provides a device for detecting the sedimentation of magnetorheological fluids, which has a very simple design and operation, but the functional capabilities of the device and the accuracy of sedimentation detection in a magnetorheological fluid are as good as the nearest analogues.

The operation of the present invention is based on measuring the electrical resistance of a magnetorheological fluid when the fluid is exposed to a magnetic field. The resistance depends on the following parameters: temperature, how long the liquid is exposed to the magnetic field, initial particle concentration, magnetic field strength and degree of sedimentation. In the absence of a magnetic field, the resistance of the fluid is very high (depending on the fluid, it can reach up to 600 megabytes). Therefore, in the case of the present invention, the electrical resistance is measured when the magnetorheological fluid is exposed to a magnetic field. To measure the resistance, a sensor of its own design is used, consisting of two contact plates separated by a gap of 1 mm.

The device provided can be adapted to mechanisms that use magnetorheological fluid: magnetorheological clutches, brakes, vibration dampers and shock absorbers.

DETAILED DESCRIPTION OF THE INVENTION FIG. the schematic diagram (without magnetorheological fluid and sealant) and section A-A (with magnetorheological fluid and sealant) of the device for sedimentation of magnetorheological fluid is shown.

the device for detecting sedimentation of the magnetorheological fluid 4 consists of two sensors 2 and 3 built into the housing 1, each of which consists of two plates of electrically conductive material separated from each other by a gap of 1 mm. These sensors 2 and 3 are located in the upper and lower parts of the housing 1, because due to sedimentation, the concentration of particles is different at different places in the liquid. The plates of sensors 2 and 3 are insulated from the housing 1. The liquid 4 is prevented from leaking by a seal 5. The resistance is measured by a megohmmeter located in a programmable logic controller 7, which is connected by wires 6 to sensors 2 and 3.

The device for detecting sedimentation of magnetorheological fluid works as follows:

In the upper and lower parts of the mechanism, the Mn-series electrical resistance is measured over time by a logic controller. The degree of sedimentation is determined by the ratio of these resistances. Depending on the composition of the magnetorheological fluid, the initial particle concentration and the characteristics of the device, this resistance may vary. Before using this device, it is necessary to perform initial measurements and calibrate the device in order to adapt it to the sedimentation of a particular mechanism.

Compared to the closest analogue, the device presented in this description is superior in that it does not take up extra space in the devices, and the device is simplified while maintaining its functional capabilities and the accuracy of sedimentation in the magnetorheological fluid.

Brief description of the drawing fig. Schematic diagram of the device for determining the sedimentation of a magnetorheological fluid (without magnetorheological fluid and seal) and AA section (with magnetorheological fluid and seal): 1 - housing of the measuring mechanism, 2 upper resistance measuring sensor, 3 - lower resistance measuring sensor, 4 - magnetorheological fluid , 5 - seal, 6 - wires, 7 - programmable logic controller.

Claims (2)

DEFINITION DEFINITION 1. A device for determining magnetoreological fluid sedimentation comprising a housing and sensors therein, characterized in that the sensors consist of two plates of electrically conductive material. 2. Device for detecting magnetoreological fluid sedimentation according to claim 1, characterized in that the plates are separated by a gap.