JP2003214480A - Damping force adjusting device of damper - Google Patents

Abstract

(57) [Problem] To secure a wide variable range of damping force by rapidly and largely changing the viscosity of a magnetic fluid by efficient magnetic flux convergence while reducing the size and weight and reducing power consumption. Ensure that a sufficient damper effect can always be exerted against a wide range of vibrations. SOLUTION: A plurality of annular concave portions 1a, 1a are formed in an outer peripheral portion of a magnetic material piston member 1 slidably fitted and held in a magnetic material material cylindrical casing 2 in the sliding direction. Electromagnets 5A, 5B are housed and arranged in the recesses 1a, 1a with the same poles facing each other, and a capsule-shaped magnetic fluid 4 is formed between the inner peripheral surface of the cylindrical casing 2 and the outer peripheral surface of the piston-like member 1 in an annular shape. And a magnetic flux control device that adjusts the magnitude of the magnetic flux generated in the magnetic circuit 6 by changing the magnetic force of the electromagnets 5A and 5B.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, when a structure such as a building is vibrated by an earthquake or wind, the vibration energy is absorbed to prevent the entire structure. This is a damper damping force adjustment device used to shake or suppress the relative displacement between structural members.Specifically, the viscosity is adjusted by adjusting the magnitude of the magnetic flux with the change in the electromagnet and its magnetic force. The present invention relates to a damping force adjusting device for a damper having a variable damping force using a changing magnetic fluid. 2. Description of the Related Art As a damping force adjusting device for a damper using a magnetic fluid, a damper comprising a cylindrical casing filled with a magnetic fluid and a piston relatively movable in the magnetic fluid in the casing has conventionally been used. As a variable mechanism for changing the movement resistance of the piston, an electromagnet is provided on the casing side for applying a magnetic flux to the magnetic fluid filled therein, and the magnetic force of the electromagnet is adjusted by adjusting the magnetic force of the electromagnet. 2. Description of the Related Art There is known a damping force adjustment device for a damper in which the size is changed and the viscosity of a magnetic fluid is increased or decreased to thereby change the moving resistance of a piston to make the damping force variable (for example, see Patent Document 1). . In addition, a piston is relatively slidably fitted in a cylinder containing a magnetic fluid, and an electromagnet is provided in a magnetic fluid passage communicating with the cylinder, and a magnetic force applied to the magnetic fluid by adjusting the magnetic force of the electromagnet is provided. There is also known a damping force adjusting device for a damper in which the damping force is varied in the same manner as described above by changing the size of the magnetic fluid and increasing or decreasing the viscosity of the magnetic fluid (for example, see Patent Document 2). [Patent Document 1] Japanese Patent Application Laid-Open No. 7-197976 [Patent Document 2] Japanese Patent Application Laid-Open No. 5-26287 [0004] However, the damping force adjustment of the conventional damper described above. In each of the devices, a single electromagnet is simply arranged in an annular shape around the magnetic fluid, so adjusting the magnetic force of this electromagnet to change the magnitude of the magnetic flux applied to the magnetic fluid Although it is possible to change the viscosity of the magnetic fluid, it is technically difficult to vary the damping force over a wide range only by changing the viscosity of the magnetic fluid because the magnetic flux diverges and loss easily occurs. . In particular, in order to increase the viscosity of the magnetic fluid until the relative movement between the piston and the casing or the cylinder is restricted (position is fixed), a considerably large electric power including a loss of magnetic flux is required. Also, in order to increase the variable range of the damping force using a single electromagnet, use a large magnetic circuit made of a magnetic material to converge the magnetic flux,
Alternatively, a high-power electromagnet must be used. As a result, not only is the entire damper increased in size and weight, but also the power consumption is further increased, which is not preferable in terms of running costs. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to reduce the size and weight of the magnetic fluid, reduce the power consumption, and rapidly and efficiently reduce the viscosity of the magnetic fluid by efficiently converging the magnetic flux. It is an object of the present invention to provide a damper damping force adjusting device capable of ensuring a wide range of damping force by largely changing the damping force, and capable of always exerting a sufficient damper effect on a wide range of vibrations. In order to achieve the above object, a damping force adjusting device for a damper according to the present invention comprises a magnetic material piston member in a magnetic material cylindrical casing. A damping force adjusting device for a damper, which is fitted and held slidably in an axial direction, wherein a plurality of annular concave portions are formed in an outer peripheral portion of a piston-like member in a sliding direction thereof, and an electromagnet is provided in these concave portions. A capsule in which the same poles of adjacent electromagnets are housed and arranged so as to face each other, and the entire periphery of the capsule is sealed between the inner peripheral surface of the cylindrical casing and the outer peripheral surface of the piston-like member by a sealing material. The magnetic fluid formed in a circular shape is interposed in an annular shape, and changes the magnetic force of the electromagnet to change the magnitude of the magnetic flux generated in the magnetic circuit formed by each electromagnet, the piston-like member, and the cylindrical casing. adjust And a magnetic flux control device. According to the present invention having the above-described characteristic configuration, in the magnetic circuit formed by each electromagnet, the piston-like member, and the cylindrical casing, the magnetic circuit is formed between two adjacent electromagnets of the same polarity. Since the magnetic fluid of the capsule-shaped body is interposed in the magnetic circuit part, the magnetic flux is converged at a high density in the area where the capsule-shaped magnetic fluid is interposed, and the viscosity of the magnetic fluid, It is possible to increase and decrease the movement resistance of the shaped member rapidly and efficiently. As a result, the output of each electromagnet may be small, and it is not necessary to use a large-sized magnetic circuit. Further, the use of a small-sized magnetic fluid configured in a capsule shape allows the entire damper to be reduced in size, weight, and A wide variable range of the damping force can be ensured while reducing power consumption, and a sufficient damper effect can be always exerted for a wide range of vibration. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional structural view showing an embodiment of a damping force adjusting device for a damper according to the present invention, and FIG. 2 is a principle configuration diagram of the damping force adjusting device. This damper D
A piston-like member 1 made of a magnetic material is fitted and held in a cylindrical casing 2 made of a magnetic material so as to be slidable in its axial direction (directions of arrows ab). A damping force adjusting device B is incorporated between the cylindrical casing 2 and the piston-like member 1 in the damper D. The above-mentioned damping force adjusting device B is provided on the outer peripheral portion of the piston-like member 1 in two upper and lower annular recesses 1 along the sliding direction.
a, 1a are formed, and two annular electromagnets 5A, 5B are housed, arranged and fixed in these annular recesses 1a, 1a with their same poles (N and N or S and S) facing each other. The outer peripheral surface of the cylindrical casing 2 and the piston-like member 1
A magnetic fluid 4 formed in a capsule-like body whose entire periphery is hermetically sealed by a sealing material 3 is annularly interposed between the opposing surfaces of the electromagnet and the two electromagnets. 5A and 5B, a magnetic member made of a piston-like member 1 made of a magnetic material, and a cylindrical casing 2 form a magnetic circuit 6 having a part of the opposite electromagnets of the two electromagnets 5A and 5B. The configuration is such that the capsule-shaped magnetic fluid 4 is interposed in the magnetic circuit portion 6a between the opposing same poles of the two electromagnets 5A and 5B. The coils (not shown) forming the two electromagnets 5A and 5B in the above-described damping force adjusting device B are provided with a magnetic circuit 6 and a magnetic circuit by changing the magnetic force by adjusting the energizing current. A magnetic flux control device 7 capable of adjusting the magnitude of the magnetic flux generated in the portion 6a is electrically connected. In the damper damping force adjusting device B according to the embodiment having the above-described configuration, a current is supplied to the coils of the two electromagnets 5A and 5B through the magnetic flux control device 7 so that the magnetic flux is applied to the magnetic circuit 6. At this time, in the magnetic circuit portion 6a where the same poles of the two electromagnets 5A and 5B face each other, the magnetic flux is converged to a high density state, and the converged magnetic flux causes the viscosity of the capsule-shaped magnetic fluid 4 to increase and decrease. Will be done. Therefore, two electromagnets 5
The viscosity of the capsule-shaped magnetic fluid 4 is reduced by controlling the current supplied to the magnetic fluids A and 5B via the magnetic flux controller 7 to adjust the magnitude of the magnetic flux generated in the magnetic circuit 6 and the magnetic circuit portion 6a. It is rapidly and greatly changed under electric power. As a result, the movement resistance of the piston-like member 1 changes abruptly, and the damping force can be varied over a wide range, so that a sufficient damper effect can be always exerted for a wide range of vibration. The capsule-shaped magnetic fluid in the present invention may be any fluid whose viscosity changes depending on the magnitude of the magnetic flux.
Bingham fluid in which ferromagnetic metal fine particles having a mean particle size are dispersed. The fluid has a working temperature range of -40 to 150 ° C., and has a viscosity that changes depending on the magnitude of magnetic flux. It is desirable to use a capsule shaped MR fluid. As described above, according to the present invention, of the plurality of electromagnets housed and arranged in the plurality of annular recesses formed on the outer peripheral portion of the piston-like member, the same poles oppose each other. By encapsulating magnetic fluid in a part of the magnetic circuit formed between the opposing poles of adjacent electromagnets arranged in a state, the magnetic flux is concentrated in the area where the capsule magnetic fluid intervenes with low power consumption. And the high-density magnetic flux allows the viscosity of the capsule-shaped magnetic fluid and, consequently, the movement resistance of the piston-shaped member to be rapidly increased and increased and decreased efficiently. Therefore, the output of each electromagnet may be small, and there is no need to use a large magnetic circuit. Further, the use of a small-sized magnetic fluid formed in a capsule shape makes it possible to reduce the size, weight and consumption of the entire tamper. While reducing power, a wide variable range of the damping force is ensured, so that a sufficient damper effect can always be exerted reliably and reliably over a wide range of vibration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional structural view showing an embodiment of a damping force adjusting device for a damper according to the present invention. FIG. 2 is a principle configuration diagram of a damping force adjusting device in the embodiment. [Description of Signs] 1 Piston-like member 2 Cylindrical casing 3 Sealing material 4 Capsule-like magnetic fluid 5A, 5B Electromagnet 6 Magnetic circuit 6a Magnetic circuit part 7 Magnetic flux control device D Damper B Damping force adjusting device

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takeshi Oku             1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka             Toyo Tire & Rubber Co., Ltd. (72) Inventor Shuichi Okamoto             1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka             Toyo Tire & Rubber Co., Ltd. F-term (reference) 3J069 AA50 CC13 DD25 EE62

Claims (1)

Claims 1. A damper damping force adjusting device comprising a magnetic material piston member fitted and held in a cylindrical casing made of a magnetic material so as to be slidable in an axial direction. A plurality of annular recesses are formed in the outer peripheral portion of the piston-like member in the sliding direction thereof, and the electromagnets are housed and arranged in these recesses in such a state that the same poles of the adjacent electromagnets face each other. Between the inner peripheral surface and the outer peripheral surface of the piston-shaped member, a magnetic fluid in a shape of a capsule surrounded by a sealing material around the entire periphery in a sealing state is provided in an annular shape, and the magnetic force of the electromagnet is reduced. A damping force adjusting device for a damper, comprising: a magnetic flux control device that changes the magnitude of a magnetic flux generated in a magnetic circuit formed by each of the electromagnets, the piston-like member, and the cylindrical casing. .