Piston for magneto-rheological damper
US-11313429-B2 · Apr 26, 2022 · US
US12565725B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-12565725-B2 |
| Application number | US-202318210321-A |
| Country | US |
| Kind code | B2 |
| Filing date | Jun 15, 2023 |
| Priority date | Jul 13, 2022 |
| Publication date | Mar 3, 2026 |
| Grant date | Mar 3, 2026 |
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A washing machine including a cabinet; a tub disposed in the cabinet; a drum arranged inside the tub so as to be rotatable; at least one damper coupled to the cabinet and the tub, and including at least one coil configured to generate a magnetic field based on a voltage applied to the at least one coil, and a magneto-rheological fluid having a viscosity that changes based on the magnetic field; and a controller configured to control the voltage applied to the at least one coil based on a rotation speed of the drum and a vibration value of the tub so as to generate the magnetic field to change the viscosity of the magneto-rheological fluid to reduce the vibration of the tub caused by the rotation of the drum.
Opening claim text (preview).
What is claimed is: 1 . A washing machine comprising: a cabinet; a tub disposed in the cabinet; a drum arranged inside the tub so as to be rotatable; at least one damper coupled to the cabinet and the tub, and including: at least one coil configured to generate a magnetic field based on a voltage applied to the at least one coil, and a magneto-rheological fluid having a viscosity that changes based on the magnetic field; and a controller configured to control the voltage applied to the at least one coil based on a rotation speed of the drum and a vibration value of the tub so as to generate the magnetic field to change the viscosity of the magneto-rheological fluid to reduce the vibration of the tub caused by the rotation of the drum. 2 . The washing machine of claim 1 , wherein the controller is configured to adjust a duty ratio of the voltage applied to the at least one coil to a first value based on the vibration value of the tub being less than a reference value, and adjust the duty ratio of the voltage applied to the at least one coil to a second value which is greater than the first value based on the vibration value of the tub being greater than the reference value. 3 . The washing machine of claim 1 , wherein the controller is configured to adjust a duty ratio of the voltage applied to the at least one coil based on a first lookup table in a first section of a washing machine process in which the drum is accelerated from a first speed to a second speed, and adjust the duty ratio of the voltage applied to the at least one coil based on a second lookup table that is different from the first lookup table in a second section of the washing machine process in which the drum is accelerated from the second speed to a third speed. 4 . The washing machine of claim 1 , wherein the at least one coil includes: a first coil configured to receive a first voltage from a first power source, and a second coil configured to receive a second voltage from a second power source, and the controller is configured to selectively apply the first voltage and the second voltage to the first coil and the second coil, respectively, based on the rotation speed of the drum and the vibration value of the tub. 5 . The washing machine of claim 4 , wherein the controller is configured to apply the first voltage to the first coil based on the vibration value of the tub falling within a first reference range, apply the second voltage to the second coil based on the vibration value of the tub falling within a second reference range, and apply the first voltage and the second voltage to the first coil and the second coil, respectively, based on the vibration value of the tub falling within a third reference range. 6 . The washing machine of claim 1 , wherein the at least one damper includes: at least one front damper with a first coil and disposed close to a front side of the tub, and at least one rear damper with a second coil and disposed close to a rear side of the tub, and the controller is configured to control the voltage applied to the first coil and the second coil so that a damping force of the at least one rear damper is greater than a damping force of the at least one front damper in a first section of a washing machine process in which the drum is accelerated from a first speed to a second speed, and control the voltage applied to the first coil and the second coil so that the damping force of the at least one front damper is greater than the damping force of the at least one rear damper in a second section of the washing machine process in which the drum is accelerated from the second speed to a third speed. 7 . The washing machine of claim 6 , wherein 160 RPM is in between the first speed and the second speed, and 230 RPM is in between the second speed and the third speed. 8 . The washing machine of claim 1 , further comprising: a vibration sensor configured to detect the vibration value of the tub, wherein the at least one damper includes: at least one front damper with a first coil and disposed close to a front side of the tub, and at least one rear damper with a second coil and disposed close to a rear side of the tub, and the controller is configured to determine a first vibration value generated at the front side of the tub and a second vibration value generated at the rear side of the tub based on the vibration value of the tub detected by the vibration sensor, control the voltage applied to the first coil based on the first vibration value, and control the voltage applied to the second coil based on the second vibration value. 9 . The washing machine of claim 8 , wherein the controller is configured to control the voltage applied to the first coil and the second coil so that a damping force of the front damper is greater than a damping force of the rear damper based on the first vibration value being greater than the second vibration value, and the controller is configured to control the voltage applied to the first coil and the second coil so that the damping force of the rear damper is greater than the damping force of the front damper based on the second vibration value being greater than the first vibration value. 10 . The washing machine of claim 9 , wherein the controller is configured to adjust a duty ratio of the voltage applied to the first coil to be higher than a duty ratio of the voltage applied to the second coil such that the damping force of the front damper is greater than the damping force of the rear damper, and adjust the duty ratio of the voltage applied to the second coil to be higher than the duty ratio of the voltage applied to the first coil such that the damping force of the rear damper is greater than the damping force of the front damper. 11 . A method of controlling a washing machine including at least one damper, including at least one coil configured to generate a magnetic field based on a voltage applied to the at least one coil and a magneto-rheological fluid having a viscosity that changes depending on the magnetic field, the at least one damper coupled to a cabinet and a tub, the method comprising: controlling the voltage applied to the at least one coil based on a rotation speed of the drum and a vibration value of the tub so as to generate the magnetic field to change the viscosity of the magneto-rheological fluid to reduce the vibration of the tub caused by the rotation of the drum. 12 . The method of claim 11 , wherein the controlling the voltage applied to the at least one coil includes: adjusting a duty ratio of the voltage applied to the at least one coil to a first value based on the vibration value of the tub being less than a reference value, and adjusting the duty ratio of the voltage applied to the at least one coil to a second value which is greater than the first value based on the vibration value of the tub being greater than the reference value. 13 . The method of claim 11 , wherein the controlling the voltage applied to the at least one coil includes: adjusting a duty ratio of the voltage applied to the at least one coil based on a first lookup table in a first section of a washing machine process in which the drum is accelerated from a first speed to a second speed, and adjusting the duty ratio of the voltage applied to the at least one coil based on a second lookup table that is different from the first lookup table in a second section of the washing machine process in which the drum is accelerated from the second speed to a third speed. 14 . The method of claim 11 , wherein the
characterised by the control method or circuitry (control of mechanical oscillations per se G05D19/00) · CPC title
Control arrangements · CPC title
Fluid damping · CPC title
Imbalance; Noise level · CPC title
Changing sequence of operational steps; Carrying out additional operational steps; Modifying operational steps, e.g. by extending duration of steps · CPC title
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