JPH011470A - 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 actuator having a structure as shown in FIG. 3 has been used.

1 is a so-called pneumatic cylinder type 1-cut machine body,
A cylinder is formed by the cylinder outer wall 2.3 and the arms 4, 5, and a slider 6 is interposed inside the cylinder, which separates the cylinder into two spaces 7.8 and a left chamber 7, shown in the figure. 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 discharge port of the air pressure source 10 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 is a surge tank connected to the discharge port of the pneumatic pressure source 10 to absorb the pulsation of the pneumatic pressure source 10. 14 is also a pneumatic source l
The diameter of the variable orifice 11 is controlled in accordance with the output of a pressure detector connected to the discharge port of the air pressure source 10, 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 and the cylinder left chamber 7 when turned on, and cuts off the air passage when turned 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 the 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 port 9, so the slider 6 is urged rightward by this pressure. 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 moved 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 10 is linearly controlled by throttle 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 made with this point in mind, and it is an object of the present invention to provide an actuator that does not require an external pneumatic source and can be electrically controlled.

[Means for solving problems]

In the magnetic fluid actuator according to the present invention, a wire is connected to a rotating bobbin supported by an arm, and each end of the wire is connected to an actuator element formed by enclosing a magnetic fluid in an elastic film body via a spring. An excitation coil for exciting the actuator element is provided, and a reel for winding an external load driving wire is provided on the boob.

[Effect]

The magnetic fluid type actuator according to 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 actuator The stroke can be controlled by moving the rotational position of the pulley, which is balanced by an element and a spring.

〔Example〕

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

FIGS. 1 and 2 show an embodiment of the actuator according to the present invention, in which 1 is an actuator body, 20a,
Reference numeral 20b denotes an actuator element constructed by enclosing magnetic fluids 21a and 21b in an elastic membrane body.Holder parts 22a and 22b of these actuator elements are supported by a fixed end 27, and the other end sides 23a and 23b are spring 2
4m and 24b, and the other ends of this spring are connected 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 external load is applied to the notch 34 of this reel 30!
A rod insertion hole 32 is provided into which the distal end rod 31 of the JK mover mover ear is inserted and fixed. Also, pulley 29 is arm 3
The arm 33 is held at one end of the arm 33, and the other end of the arm 33 is fixed to the fixed end 27. Numerals 35a and 35b are excitation coils for applying a magnetic field to the magnetic fluid actuator elements 20a and 20b, and are provided coaxially with the actuator elements 20a and 20b.

Next, the operation of this magnetic fluid type actuator will be explained. FIG. 1 shows a case where the re-excitation coils 35a and 35b are in an excited state, and the magnetic fluid actuator element 20a,
Since a magnetic field acts on 20b, the magnetic fluid 21m,
21b tends to take on a roughly spherical shape under the action of its surface tension in a non-excited state, but under the action of a magnetic field, its shape is deformed so that it is stretched in the length direction, and the shape of the spring becomes approximately elliptical. Since the contraction forces are balanced and stabilized, the pulley 29 stops at the equilibrium position shown. Therefore, the external load driving wire 18 is also located at a corresponding position.

FIG. 2 shows a state in which only the excitation coil 35b is energized, and the actuator element 20a attempts to restore its shape to an approximately spherical shape because there is no acting magnetic field.
After the contraction force is generated, the pulley is rotated clockwise by <90° as shown in the figure and then stopped. Therefore, the external load driving wire 18 is also driven rightward by a predetermined stroke. Actually external load WjAvh wire 18
Since a driving torque is required, the force balance of the actuator is determined at the position where the contraction force of the magnetic fluid actuator element 20a, the contraction force of the springs 24m and 24b, and the tension of the external load drive wire 18 are balanced. The pulley 29 is stationary and correspondingly the external load drive wire 1
8 will be positioned.

By the way, when the magnetic fluid 21 is saturated by the magnetic field, the amount of horizontal deformation of the magnetic fluid 21 is proportional to the applied magnetic field, and within this range, the stroke of the external load drive wire 18 is equal to that of the coil 35. This means that it can be controlled almost in proportion to the excitation current. Also, excitation coil 35m
is excited, the pulley 29 is driven counterclockwise, and the external load drive wire 18 is driven completely symmetrically to the left in the drawing.

〔Effect of the invention〕

As described above, according to the magnetic fluid actuator according to the present invention, the stroke of the external load driving wire can be controlled 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 above-mentioned stroke in response to the excitation current, which is structurally simple, eliminates the need for a pneumatic source, and eliminates mechanical wear and deterioration factors. Less reliable actuators can be obtained.

[Brief explanation of drawings]

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 the actuator body, 18 is the external load WAT
o wire, 20a, 20b are actuator elements, 2
1a and 21b are magnetic fluids, 24a and 24b are springs, 27 is a fixed end, 28 is a wire, 29 is a pulley, 3
0 is the reel, 31 is the tip rod, 32 is the rod insertion port,
33 is an arm, 34 (notch portion), and 35a and 35b are excitation coils. In addition, the same reference numerals in the drawings indicate the same or equivalent parts.

Claims (1)

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