JPS599331A - Shock absorber - Google Patents

Abstract

PURPOSE:To automatically adjust damping force so as to be able to produce the damping force stable to temperature change by a method wherein magnetic fluid, the viscosity of which is changed by magnetic force, is used as buffer medium and the viscosity of said magnetic fluid is changed electrically. CONSTITUTION:A hollow piston rod 3, a piston 2 with oil passages, and a fixed rod 4, at the root of which an exciting coil 6 is wound, are provided in a cylinder 1, within which magnetic fluid is sealed. The cylinder 1, the piston 2 and the fixed rod 4 form a magnetic circuit 7. The damping force is automatically regulated by the change of the viscosity of the magnetic fluid passing through the orifice 5 formed between the fixed rod 4 and the hollow rod 3 due to the temperature-change dependent change of the amount of electric current passing through the exciting coil 6 and an element 8, the resistance of which lowers itself in proportion to the rise of its temperature, connected with each other in series.

Description

[Detailed Description of the Invention] The present invention relates to a shock absorber that automatically adjusts damping force using extremely simple means.The present invention relates to a shock absorber that automatically adjusts damping force using extremely simple means. , there is an oil damper. A typical oil damper is one in which a piston slides inside a cylinder filled with oil, and the damping force generated when the oil passes through an oil passage provided in the piston absorbs vibrations and shocks. However, in conventional devices of this type, as the oil temperature rises, the viscosity of the oil decreases, and the damping force decreases accordingly, making it impossible to generate a stable damping force, resulting in insufficient buffering capacity. In some cases.

Jin's invention provides a buffer device that solves these drawbacks, and its characteristics are that the buffer medium is a magnetic fluid whose viscosity changes due to magnetic force, and the viscosity of the magnetic fluid is electrically controlled. The damping force is automatically adjusted by changing the temperature, and a stable damping force can be generated even when the temperature changes.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

The drawing shows an example of application to a very general oil damper, where il+ is a magnetic fluid, l' is a piston (2) is a hollow piston rod, and a piston (2) is a hollow piston rod. ) and piston rod (31) are provided with an oil passage (2-1) and an oil hole (3-1), respectively. =・−゛The diameter of the hollow piston/rod (3) is smaller than 10 mm, and the piston rod (31 is inserted in such a way that a τ” ring (5) is formed at the opening of the piston rod. This fixing rod (4)
An excitation coil (6) is wound around the base of the cylinder (1) and the piston (
2) and the fixed rod (4) are formed with a magnetic circuit (7), so that the viscosity of the magnetic fluid flowing through the orifice (5) can be changed by the A current (magnetic field) of the excitation coil (6). . A method of changing the amount of current flowing through the excitation coil (6) is to connect an element whose resistance value decreases with temperature rise, such as a thermistor (8), in the middle of the circuit between the excitation coil (6) and the power supply. Excitation coil (
6) 4 Weight (magnetic field) can be adjusted. The orifice (
5) The viscosity of the magnetic fluid flowing through the magnetic fluid can be changed.

In the above shock absorber, when the piston rod (31) is pressed and the piston (2) moves inward, that is, during compression, a part of the magnetic fluid in the oil chamber (A) is transferred to the piston (2).
As well as entering the oil chamber (B) through the oil passage (2-1),
Another magnetic fluid flows through the orifice (5) and into the oil chamber (B) via the inner chamber of the piston rod (3). During expansion, the magnetic fluid flows in the opposite direction to that during compression, creating a damping force.

Now, when the excitation coil (6) is energized, the cylinder (1)
, a magnetic circuit (
A force is created which changes the viscosity of the magnetic fluid passing through the orifice (5). This change in viscosity causes orifice 15
), the damping force changes as the flow resistance of the magnetic fluid changes. The viscosity of the magnetic fluid is determined by the excitation coil (6)
It can be arbitrarily changed depending on the magnitude of the current applied to. That is, when the current flowing through the exciting coil (6) is large, the viscosity of the magnetic fluid increases, and when the exciting current is small, the viscosity of the magnetic fluid decreases. Therefore, if a large current is passed through the excitation coil (6), the viscosity of the magnetic fluid increases and the flow resistance of the magnetic fluid passing through the orifice (5) increases, so a large damping force can be obtained, and conversely, the excitation coil ( 6), the viscosity of the magnetic fluid becomes smaller and the flow resistance of the magnetic fluid passing through the orifice (5) decreases, resulting in a smaller damping force.8 Adjustment of this damping force is achieved by the excitation coil. (6) This can be done by a thermistor inserted in the middle of the power supply circuit.In other words, the I-mistor detects the oil temperature and functions to lower the resistance when the oil temperature rises. be.

Furthermore, this invention can automatically adjust the damping force by simply changing the amount of current applied to the excitation coil installed in the cylinder, so it generates a stable damping force even if the oil temperature in the cylinder is 1=J1-. Therefore, it provides a shock absorbing device with excellent shock absorbing capacity.

[Brief explanation of drawings]

The drawing is a partially cutaway front view showing an embodiment of the present invention. 1...Cylinder, 2...Piston, 2-1...
Oil passage, 3... Hollow piston rod, 3-1... Oil hole, 4... Fixed rod, 5... Orifice, 6...
・Exciting coil, 7...Magnetic circuit, A, B...Oil chamber

Claims (1)

[Claims] It consists of a cylinder filled with magnetic fluid, a hollow piston rod through which magnetic fluid flows, and a piston with an oil passage that slides inside the cylinder.It is protruded from one end of the cylinder and has an excitation coil wound around its base. A fixed iron is inserted into the hollow piston rod, an orifice is provided between the fixed rod and the hollow piston rod, and a magnetic circuit is formed in the cylinder, piston, and fixed iron by energizing the excitation coil. Elements whose resistance value decreases as the temperature rises are connected in one line to the excitation coil so that the amount of current to the excitation coil follows the temperature change.
A damping device characterized in that the damping force is automatically adjusted by changing the viscosity of the magnetic fluid passing through the orifice.