SU1247587A1 - Step-by-step damp drive - Google Patents

Description

The invention relates to (pneumatic) hydraulic actuators and can be used for positioning (pneumatic) hydraulic motors, in particular in machine feed drives, in manipulator drives.

The purpose of the invention is to simplify the design and increase reliability in a wide frequency spectrum of vibrations.

FIG. 1 is a schematic diagram of the proposed drive; in fig. 2 is a section A-A in FIG. one; in fig. 3 shows a section BB in FIG. 2

The positional damped actuator contains a source of hydraulic energy 1 connected through the hydraulic distributor 2 to the working cavity 3 and 4 of the hydraulic engine 5, which includes a piston 6 with a double-sided rod 7. In addition, the actuator contains a damping device, including two separators installed in the housing 8, in the form of bellows 9 and 10 with the formation of successive three cavities 11 -13. The two extreme cavities 11 and 13 are connected with working cavities 3 and 4. The central cavity 12 is filled with a magnetorheological suspension and divided into two parts (not marked), communicated with each other through a throttling device made in the form of a flat labyrinth channel 14 (Fig. 2 and 3) in the housing 8 of a non-magnetic material covered by a permanent magnet 15. A ball bearing 16 made of a non-magnetic material is located between the housing 8 and the permanent magnet 15.

The drive works as follows.

The curve of the flow of a magnetorheological suspension can be approximated by the expression

l bo (Hi),

where t is the tangential stress;

Y is the velocity gradient transverse to the direction of the flow;

H is the magnetic field strength;

Ф is the angle between the direction of the flow and the magnetic field;

That is the ultimate shear stress.

When the pressure differential between cavity 3 and 4 of the hydraulic motor, which causes tangential stress in the magnetorheological suspension in the labyrinth channel 14, is less than the ultimate shear stress, channel 14 is closed, and in the case of an oscillatory transient process at the moment when the shear stress exceeds the ultimate stress shear channel 14 opens and flow begins through it, the pressure oscillations are quenched due to hydraulic resistance due to the conductivity of channel 14 and two

0

parts of the cavity 12 of the housing 8 of the damping device. When the transient process decays, the cavities 3 and 4 of the hydraulic engine 5 are again disconnected, since the channel 14 is again locked.

The ultimate shear stress of the magneto-rheological suspension varies considerably with a change in the strength of the magnetic field and with a change in the angle

between the direction of the flow and the magnetic field ranging from zero to 90 °. Thus, it is possible to easily re-adjust the damping device by rotating the permanent magnet 15 around the axis of the channel 14. If it is necessary to move the inertial load (not indicated) to a predetermined position, the control valve 2 connects the cavities 3 and 4 of the hydraulic motor 5 to the source of hydraulic energy 1 and under the influence of pressure differential on the piston 6 of the hydraulic engine 5 inertial load begins to move, and during a uniform movement of the inertial load, the pressure drop in cavities 3 and 4 of the hydraulic engine 5, consequently, in the cavities 11 and 13 associated with them, the damping device creates a tangential stress in the magnetorheological suspension in channel 14 less than the ultimate shear stress, and, therefore, parts of the cavity 12 of the damping device are separated from each other. When an inertia load approaches a predetermined position, the control valve 2 switches to the neutral position, and the flow rate of the working fluid passing through the hydraulic motor 5 is reduced. Inertial load deceleration begins. Arising from

5, the pressure fluctuations in cavity 3 and 4 of the hydraulic engine 5 create tangential stresses in the magnetorheological suspension in the labyrinth channel 14 greater than the ultimate shear stress. The flow of the magnetorheological suspension begins through channel 14 and, consequently, cavities 3 and 4 of hydraulic engine 5 communicate with each other through bellows 9 and 10, cavities 11-13 and open channel 14. Oscillation occurs due to resistance

5 channel 14.

Rotating the permanent magnet 15 around the axis of the labyrinth channel 14 changes the angle between the direction of flow of the magnetorheological suspension in channel 14 and the field of the standing magnet 15, and since the ultimate shear stress depends on this angle (when the angle changes from 0 to 90 ° The shear stress of the magnetorheological suspension is more than doubled), then when the magnet is turned

5–15 changes the pressure differential level in cavities 3 and 4 of hydraulic engine 5, at which channel 14 opens,

those. there is a reorganization of the damping device.

The implementation of the damping device of the proposed design allows to increase the reliability and simplify the design of the drive, since it practically

there is no threat of jams and seizures of moving inertial masses and reduced requirements for the accuracy of manufacturing structural components, as compared with the known designs of damping devices. Compressed air may be used as a working medium.

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Claims (3)

1. POSITIVE DAMPING DRIVE containing a hydraulic energy source connected through a hydraulic distributor to the working cavities of the hydraulic motor, a damping device comprising two separators installed in the housing with the formation of three cavities in series, the two extreme cavities of which are connected to the working cavities of the hydraulic motor and a throttling device, characterized in that, in order to simplify the design and improve reliability in a wide frequency spectrum of oscillations, the third central cavity the damping device is filled with a magnetorheological suspension and is divided into two parts communicating with each other through the throttle device in the form of a flat labyrinth channel in the housing of nonmagnetic material and covered by a permanent magnet rotatably mounted relative to the housing it. 2. Drive on π. 1, characterized in that the dividers are made in the form of bellows. 3. Drive on π. 1, characterized in that between the housing of a non-magnetic material and a permanent magnet an additional ball bearing is made of non-magnetic material. Fig .;