초록 ▼

A damper obtaining damping force by the frictional resistance imparted by the viscosity of the magnetic viscous fluid is disclosed. The damper is provided with a seal not only on one (lower side) of the axial outer sides of the yoke but also on the other (upper side) of the axial outer sides of the

A damper obtaining damping force by the frictional resistance imparted by the viscosity of the magnetic viscous fluid is disclosed. The damper is provided with a seal not only on one (lower side) of the axial outer sides of the yoke but also on the other (upper side) of the axial outer sides of the yoke to trap the magnetic viscous fluid within the magnetic viscous fluid filling portion at both axial outer sides of magnetic viscous fluid filling portion. Because the leakage of the magnetic viscous fluid can be prevented, no air is introduced into the magnetic viscous fluid filling portion, to allow the density of the magnetic viscous fluid within magnetic viscous fluid filling portion to be maintained at a favorable level and prevent degradation of damping force.

대표청구항 ▼

1. A damper comprising: a cylinder;a coil disposed inside the cylinder;a plurality of yokes disposed inside the cylinder so that one of the yokes is located at each axial end of the coil, respectively, and being configured to form a magnetic circuit within the cylinder;a magnetic viscous fluid retai

1. A damper comprising: a cylinder;a coil disposed inside the cylinder;a plurality of yokes disposed inside the cylinder so that one of the yokes is located at each axial end of the coil, respectively, and being configured to form a magnetic circuit within the cylinder;a magnetic viscous fluid retained on inner surfaces of the yokes and the coil;a plurality of seals disposed inside the cylinder so as to be located axially outside the yokes, the seals being configured to maintain the retention of the magnetic viscous fluid on the inner surfaces of the yokes and the coil by preventing leakage of the magnetic viscous fluid;a shaft which is supported so as to be axially reciprocable relative to the yokes, the coil, and the seals such that reciprocation of the shaft does not substantially displace the magnetic viscous fluid between the seals; anda plurality of bearings disposed axially outside the seals, the bearings being configured to support the shaft. 2. The damper according to claim 1, further comprising a bobbin disposed inside the cylinder and being wound with the coil, wherein the yokes are provided with recesses for receiving the seals, the seals being pressed into the recesses. 3. The damper according to claim 2, wherein an axial depth of the recesses is relatively increased to receive the bearings that support the shaft. 4. The damper according to claim 2, further comprising a plurality of O-rings disposed between flanges of the bobbin and the yokes, the O-rings being configured to prevent leakage of the magnetic viscous fluid. 5. The damper according to claim 2, wherein the bobbin and the yokes are bonded with an adhesive. 6. The damper according to claim 4, wherein either the flanges of the bobbin or the yokes are provided with annular recesses which are configured to receive the O-rings. 7. The damper according to claim 6, wherein the remaining other of the flanges of the bobbin or the yokes are provided with protrusions that are configured to press the O-rings received within the annular recesses. 8. The damper according to claim 6, wherein a depth of the annular recesses is less than a thickness of the O-rings. 9. The damper according to claim 8, wherein a cross sectional area of the annular recesses is greater than a cross sectional area of the O-rings. 10. The damper according to claim 6, wherein cylindrical sections of the bobbin extend outward so as to form annular protrusions on outer surfaces of the flanges, the O-rings being held between outer peripheral surfaces of the protrusions and inner peripheral surfaces of the annular recesses formed on the yokes, and wherein d1D2 when D1 represents an outer diameter of the protrusions of the bobbin, D2 represents an inner diameter of annular recesses of the yokes, d1 represents an inner diameter of the O-rings, and d2 represents an outer diameter of the O-rings. 11. The damper according to claim 6, wherein a labyrinth seal structure is provided on inner peripheral portions or outer peripheral portions of the O-rings disposed on the flanges of the bobbin and the yokes. 12. The damper according to claim 6, wherein the O-rings comprise an elastic and heat resistive material. 13. The damper according to claim 2, further comprising a resin configured to mold the coil, the bobbin, and the yokes, and O-rings disposed between a flanges of the bobbin and the yokes, the O-rings being configured to prevent leakage of the magnetic viscous fluid. 14. The damper according to claim 1, wherein each of the seals is provided with a fluid receiving portion on a magnetic viscous fluid filled portion side, and a communicating portion that communicates the fluid receiving portion and the magnetic viscous fluid filled portion. 15. A washing machine comprising: an exterior housing;a tub disposed inside the tub;a rotary tub driven in rotation within the tub;a suspension provided with a damper configured to elastically support the tub inside the exterior housing and to reduce oscillation of the tub, the damper including: a cylinder; a coil disposed inside the cylinder;a plurality of yokes disposed inside the cylinder so that one of the yokes is located at each axial end of the coil, respectively, and being configured to form a magnetic circuit within the cylinder;a magnetic viscous fluid retained on inner surfaces of the yokes and the coil;a plurality of seals disposed inside the cylinder so as to be located axially outside the yokes, the seals being configured to maintain the retention of the magnetic viscous fluid on the inner surfaces of the yokes and the coil by preventing leakage of the magnetic viscous fluid;a shaft which is supported so as to be axially reciprocable relative to the yokes, the coil, and the seals such that reciprocation of the shaft does not substantially displace the magnetic viscous fluid between the seals; anda plurality of bearings disposed axially outside the seals, the bearings being configured to support the shaft. 16. The washing machine according to claim 15, further comprising a bobbin disposed inside the cylinder and being wound with the coil, wherein the yokes are provided with a recesses for receiving the seals, the seals being pressed into the recesses. 17. The washing machine according to claim 16, further comprising a plurality of O-rings disposed between flanges of the bobbin and the yokes, the O-rings being configured to prevent leakage of the magnetic viscous fluid. 18. The washing machine according to claim 17, wherein either the flanges of the bobbin or the yokes are provided with annular recesses which are configured to receive the O-rings. 19. The washing machine according to claim 18, wherein a depth of the annular recesses is less than a thickness of the O-rings. 20. The washing machine according to claim 19, wherein a cross sectional area of the annular recesses is greater than a cross sectional area of the O-ring. 21. The washing machine according to claim 18, wherein cylindrical sections of the bobbin extend outward so as to form annular protrusions on outer surfaces of the flanges, the O-rings being held between outer peripheral surfaces of the protrusions and inner peripheral surfaces of the annular recesses formed on the yokes, and wherein d1D2 when D1 represents an outer diameter of the protrusions of the bobbin, D2 represents an inner diameter of annular recesses of the yokes, d1 represents an inner diameter of the O-rings, and d2 represents an outer diameter of the O-rings. 22. The washing machine according to claim 18, wherein the O-rings comprise an elastic and heat resistive material. 23. The washing machine according to claim 16, further comprising a resin configured to mold the coil, the bobbin, and the yokes, and O-rings disposed between flanges of the bobbin and the yokes, the O-rings being configured to prevent leakage of the magnetic viscous fluid. 24. The washing machine according to claim 15, wherein each of the seals is provided with a fluid receiving portion on a magnetic viscous fluid filled portion side, and a communicating portion that communicates the fluid receiving portion and the magnetic viscous fluid filled portion. 25. The washing machine according to claim 15, wherein the damper is connected to the exterior housing at the cylinder side and connected to the tub at the shaft side. 26. A washer dryer comprising: an exterior housing;a tub disposed inside the tub;a rotary tub driven in rotation within the tub;a suspension provided with a damper configured to elastically support the tub inside the exterior housing and to reduce oscillation of the tub;a heater configured to generate warm air; anda blower configured to blow the warm air into the rotary tub;wherein the damper includes: a cylinder; a coil disposed inside the cylinder;a plurality of yokes disposed inside the cylinder so that one of the yokes is located at axial end of the coil, respectively, and being configured to form a magnetic circuit within the cylinder;a magnetic viscous fluid retained on inner surfaces of the yokes and the coil;a plurality of seals disposed inside the cylinder so as to be located axially outside the yokes, the seals being configured to maintain the retention of the magnetic viscous fluid on the inner surfaces of the yokes and the coil by preventing leakage of the magnetic viscous fluid;a shaft which is supported so as to be axially reciprocable relative to the yokes, the coil, and the seals such that reciprocation of the shaft does not substantially displace the magnetic viscous fluid between the seals; anda plurality of bearings is disposed axially outside the seals, the bearings being configured to support the shaft. 27. A washer dryer according to claim 26, wherein the yokes are provided with a recesses for receiving the seals, the seals being pressed into the recesses.