JPH011467A - Magnetic fluid actuator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an actuator whose stroke can be controlled by controlling the current flowing through an excitation coil.

[Conventional technology]

Conventionally, a pneumatically controlled one cutuator having a structure as shown in FIG. 3 has been used.

1 is a so-called pneumatic cylinder type actuator body,
A cylinder is formed by the cylinder outer walls 2, 3 and the arms 4, 5, and a slider 6 is interposed therein, and the slider 6 separates the cylinder into two spaces 7.8. An air supply port 9 is formed in the air supply port 9 so that air can be supplied from a pneumatic source 10 via a control valve 15. On the other hand cylinder right ventricle 8
In this case, a spring 17 is telescopically interposed between the slider 6 and the arm 5. Furthermore, a holder portion 19 for the drive wire 18 is formed in the extending portion of the slider 6 . Reference numeral 11 denotes a solenoid-type variable orifice, which is interposed between the outlet of the air pressure source 1O and the atmosphere.The diameter of the orifice is linearly controlled by the current applied to the solenoid 12, and the orifice diameter is approximately equal to the degree of constriction of the orifice. The discharge pressure of the pneumatic source is controlled proportionally. 13 is the air pressure source 10
This tank is connected to the discharge port of the pneumatic pressure source 10 and is used to absorb the pulsation of the air pressure source 10. 14 is also the pneumatic source 1
A pressure detector connected to the discharge port 0 controls the diameter of the variable orifice 11 in accordance with this output, and the discharge pressure of the air pressure source 10 is controlled to a predetermined pressure.

15 is a three-way solenoid valve, which communicates the air pressure source with the left chamber 7 of the cylinder at 08:00, and cuts off the air passage when it is OFF.
It functions to stop the air supply from the air pressure source 10 and to communicate the air in the cylinder left chamber 7 to the atmosphere 16 and exhaust it.

Next, the operation of this actuator will be explained.

Now, when the three-way solenoid valve 15 is turned on, air pressure from the pneumatic source 10 is supplied to the cylinder left chamber 7 via the boat 9, and this pressure urges the slider 6 in the right direction. On the other hand, since a spring 17 is telescopically installed in the right chamber 8 of the cylinder, the slider 6 is normally biased to the left. Therefore, the slider 6 is driven to a position where the air pressure, the biasing force of the spring 17, and the tension of the wire 18 are balanced and then stopped. Therefore, the driving wire 18 is also driven by a stroke equal to the driving stroke of the slider 6. However, the drive stroke of the slider 6 is proportional to the supply pressure to the slider 6. Therefore, if the discharge pressure of the air pressure source IO is linearly controlled by throttling control of the variable orifice 11, the slider 6
The stroke amount of the wire 18 and the stroke amount of the wire 18 can also be linearly controlled.

[Problem that the invention seeks to solve]

By the way, a drawback of this actuator is that an external pneumatic source is required, which makes the system as a whole complicated and expensive.

The present invention has been developed in view of this point, and provides an actuator that does not require an external pneumatic source and can be electrically controlled.

[Means for solving problems]

The magnetic fluid actuator according to the present invention has a wire connected to a rotating pulley supported by an arm, a spring at one end of the wire, and an actuator element formed by enclosing a magnetic fluid in an elastic film body at the other end. An excitation coil is provided to connect and excite the actuator element, and the pulley is further provided with a reel portion around which an external load driving wire is wound.

[Effect]

The magnetic fluid actuator of the present invention utilizes the property that the magnetic fluid in the actuator element is stretched in the direction of the applied magnetic field, and by changing the magnitude of the current flowing through the excitation coil, The stroke can be controlled by moving the rotational position of the pulley, which is balanced by a spring.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the actuator according to the present invention, in which 1 is an actuator body, 20 is an actuator element constituted by enclosing a magnetic fluid 21 in an elastic film body, and the actuator element 20 holder part 23
One end 2B of the spring 24 is supported by the fixed end 27, and the other end 22.25 is coupled to both ends of the wire 28. The wire 28 is wound around a pulley 29, and the pulley 29 can be driven to rotate. A reel 30 for winding and driving the external load drive wire 18 is provided on one side of the pulley 29. The tip rod 3 of the external load drive wire 18 is inserted into the notch 34 of the reel 30.
A rod insertion hole 32 into which the rod 1 is inserted and fixed is provided. Further, the pulley 29 is held at one end of the arm 33, and the pulley 29 is held at one end of the arm 33.
The other end is fixed to the fixed end 27. 35 is an excitation coil for applying a magnetic field to the magnetic fluid actuator element 20, and is provided coaxially with the actuator element 20.

Next, the operation of this magnetic fluid type actuator will be explained. FIG. 1 shows a case where the excitation coil 35 is in an excited state,
Since a magnetic field acts on the magnetic fluid actuator element 20, the magnetic fluid 21 tends to take on a substantially spherical shape under the action of its surface tension in a non-excited state, but under the action of a magnetic field, the magnetic fluid 21 tends to become approximately spherical in its length direction. The pulley 29 is deformed as if being stretched and has a substantially oval shape that balances the contractile force of the spring and stabilizes, so the pulley 29 stops at the equilibrium position shown in the figure. Therefore, the external load driving wire 18 is also located at a corresponding position.

FIG. 2 shows the OFF state of the excitation coil 35.
Since the actuator element 20 has no acting magnetic field, a contractile force is generated in an attempt to restore its shape to the spherical shape, so that the pulley is driven clockwise by 30' rotation as shown in the figure and then stops. Therefore, the external load driving wire 18 is also driven rightward by a predetermined stroke. In reality, external load drive wire 18 drive torque is required, so
The balance of the forces of the actuator is such that the pulley 29 is at rest at a position where the contraction force of the magnetic fluid actuator element 20, the contraction force of the spring 24, and the tension of the external load drive wire 18 are balanced. The external load drive wire 18 will be positioned.

By the way, the amount of horizontal deformation of the magnetic fluid 21 is proportional to the applied magnetic field until the magnetic fluid 21 is saturated by the magnetic field. This means that it can be controlled approximately in proportion to the excitation current.

〔Effect of the invention〕

As described above, according to the magnetic fluid actuator according to the present invention, it is possible to control the stroke of the external load driving wire by controlling the excitation current of the exciting coil and controlling the magnetic field acting on the magnetic fluid actuator element. Moreover, it is also possible to linearly control the stroke in response to the excitation current, and it is structurally simple and does not require a pneumatic source as in the conventional case, and has fewer mechanical wear and deterioration factors. A highly reliable actuator can be obtained.

[Brief explanation of the drawing]

1 and 2 are front views showing one embodiment of the present invention, and FIG. 3 is a front sectional view showing a conventional pneumatic actuator. In the figure, 1 is an actuator body, 18 is a wire for driving an external load, 20 is an actuator element, 21 is a magnetic fluid,
22, 23 is a holder part, 24 is a spring, 27 is a fixed end, 28 is a wire, 29 is a pulley, 30 is a reel, 31
is the tip rod, 32 is the rod insertion port, 33 is the arm, 3
4 is a notch, and 35 is an excitation coil. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] an actuator element formed by enclosing a magnetic fluid in an elastic membrane; a spring coupled to the actuator element;
A wire interposed and fixed between the actuator element and the spring, a pulley driven by the wire, a reel provided on one side of the pulley that winds and drives the external load driving wire, and holds the pulley at one end. A magnetic fluid actuator comprising: an arm whose other end is supported by a fixed end; and an excitation coil for applying a magnetic field to the actuator element.