JPH04272529A - Damping force varying damper - Google Patents

Abstract

PURPOSE:To position a movable member which performs a revolution movement for a fixed supporting member, at a prescribed stop position in an exceedingly short time. CONSTITUTION:A supporting member 1 and a movable member 2 which carries out revolution or revolution movement for the supporting member 1 are provided, and the electric viscous fluid 8 is sealed in a sealed space farmed between the supporting member 1 and the movable member 2. Each electrode 9 is installed on the supporting member side and the movable member side of a sealed space 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable damping force damper for quickly and accurately stopping a movable member that performs rotational or rotational motion at a predetermined position.

0002

2. Description of the Related Art In order to position and stop a robot arm at a predetermined position, for example, which rotates relative to a support member, it is necessary to stop transmission of driving force to the robot arm and to control the driving means. Conventionally, it has been widely and generally practiced to mechanically stop it using the action of power.

0003

[Problems to be Solved by the Invention] However, in this prior art, when the robot arm stops, it performs damped vibration based on its inertial force, as shown in FIG. , there is a problem that it takes a considerable amount of time to come to a complete stop at a predetermined position, and in this case,
This was particularly important when the mass and/or rotation speed of the robot arm was large. Therefore, according to this prior art, by waiting for the robot arm to completely stop,
On the one hand, the work efficiency of the robot work will be reduced, and on the other hand, by starting the work without waiting for the robot to come to a complete stop, the work accuracy will be greatly reduced.

[0004] Therefore, it has been proposed to provide a damper with a large damping force between the support member and the robot arm in order to bring the robot arm to a complete stop at a predetermined position at an early stage. For example, there was another problem in that the drive energy required to rotate the robot arm was extremely large.

The present invention advantageously solves the problems of the prior art, and greatly shortens the damped vibration time when a movable member that rotates or performs rotational movement is positioned and stopped at a predetermined position. The present invention provides a variable damping force damper that can sufficiently reduce the energy required to drive a movable member.

[0006]

[Means for Solving the Problems] The variable damping force damper of the present invention is provided with a support member and a movable member that is rotatable or rotatable with respect to the support member, and an airtight seal is provided between the two. An electrorheological fluid is sealed in the chamber, and positive and negative electrodes are provided on the support member side and the movable member side of the sealed chamber, respectively.

[0007] In addition, another variable damper of the present invention particularly positions the end portion or intermediate portion of the movable member in a sealed space defined by a support member, and seals an electrorheological fluid in the sealed space. In addition, electrodes are provided on the support member side of the closed space, or on each of the support member side and the movable member side.

[0008]

[Function] In this variable damping force damper, when the movable member rotates or rotates, no voltage is applied to the electrodes, in other words, no electric field is generated between the electrodes, so that the viscosity of the electrorheological fluid can be adjusted individually. As a result, for example, a rotational movement of the movable member relative to the support member can be carried out efficiently with a small loss of energy.

On the other hand, when the movable member is in motion,
When positioning and stopping at a predetermined position by stopping the driving means and applying a braking force to the driving means, for example, in addition to stopping the driving means, by applying a voltage of a required magnitude to the electrodes. , the viscosity of the electrorheological fluid is
It is supposed to be increased depending on the strength of the electric field between the electrodes,
The relative displacement energy of the movable member with respect to the supporting member is
The damped vibration time of the movable member due to inertial force is effectively absorbed by the electrorheological fluid.
The movable member can be positioned and stopped at a predetermined position very quickly, with the movable member being significantly shortened compared to the prior art.

[0010] The same applies to other variable dampers of the present invention, and in these variable dampers, the driving energy of the movable members can be sufficiently reduced by not applying voltage to the electrodes. ,
Further, by applying a voltage to the electrodes, the movable member can be positioned and stopped at a predetermined position in an extremely short time. Here, the positioning and stopping of the movable member at a predetermined position for a short time can make the shape of the movable member portion located in the closed space sufficiently large in contact area with the electrorheological fluid, such as a disk. This is particularly noticeable when it comes to shapes.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. 1(a) and (b) are a plan view and a vertical cross-sectional view showing an embodiment of the present invention, respectively. In the figures, 1 indicates a fixed shaft as a supporting member, and 2 indicates a section around the fixed shaft 1. A rotating arm as an example of a rotatable movable member is shown.

Here, the rotating arm 2 can rotate around the fixed shaft 1 via a bearing 3 based on the action of a drive means (not shown) connected thereto. In this example, between the fixed shaft 1 and the rotating arm 2,
A sleeve 4 made of an insulating material is attached to the rotating arm 2, and an annular groove 5 is provided in the center of the inner peripheral surface of the sleeve 4 in the axial direction. Fixed shaft 1 via seal ring 6
By slidingly contacting the sleeve 4 and the fixed shaft 1,
A sealed chamber 7 is formed between the two.

Further, here, the electrorheological fluid 8 is sealed in the sealed chamber, the fixed shaft itself which contributes to the division of the sealed chamber 8 is used as a negative electrode, and the groove bottom of the annular groove 5 provided in the sleeve 4 is used as a negative electrode. By disposing the positive electrode 9 on the fixed shaft side and the rotating arm side of the sealed chamber 8, negative and positive electrodes are respectively provided on the fixed shaft side and the rotating arm side.

In the damper constructed as described above, when no voltage is applied to the electrodes and therefore the electrorheological fluid 8 is not affected by an electric field at all, the electrorheological fluid 8 Since it will have the lowest viscosity of the material, the pivoting movement of the pivoting arm 2 about the fixed axis 1 will be carried out under the action of the bearing 3 with a small driving force. On the other hand, when a voltage is applied to the electrodes and the electrorheological fluid 8 is placed in an electric field of a required strength, the viscosity of the electrorheological fluid 8 increases in accordance with the strength of the electric field. The relative rotation of the rotating arm 2 with respect to the fixed shaft 1 is restricted by the high viscosity electrorheological fluid 8.

Therefore, the rotating arm 2 is driven with a sufficiently small power consumption, and the complete positioning and stopping of the rotating arm 2 at a predetermined position is achieved by damping the high viscosity electrorheological fluid 8. Based on the action, as shown in FIG. 2, the forced damping vibration is performed very quickly, with a much shorter period of time than the conventional naturally damped vibration.

FIG. 3 is a longitudinal sectional view showing another embodiment, in which a sleeve 11 is attached to the outer peripheral surface of the fixed shaft 1, and another sleeve 1 is installed in the boss hole of the rotating arm 2.
2 is installed, an annular groove 13 provided in the axial center of the inner peripheral surface of the sleeve 12 installed in the boss hole, and a cylindrical groove fixed or fixed to the outer peripheral surface of the fixed shaft side sleeve 11. A sealed chamber 15 is formed between the cylindrical insulating material 14 and a positive electrode 9 provided on the inner peripheral surface of the cylindrical insulating material 14, with the rotating arm itself serving as a negative electrode. In this embodiment as well, it goes without saying that the electrorheological fluid 8 is sealed in the sealed chamber.

[0017] Also in this damper, by applying a voltage to the electrode, the rotating arm 2 can be positioned and stopped at a predetermined position extremely quickly, and the application of the voltage can be stopped. Accordingly, the rotating arm 2 can be rotated with a small driving force.

FIG. 4 is a longitudinal sectional view showing still another embodiment of the present invention, in which a fixed plate 21 and a housing member 22 fixed thereto constitute a supporting member, and there is a space between them. , a closed chamber 23 having a substantially trapezoidal cross-sectional shape is formed, and the housing member 2
2, the rotating shaft 24 as a movable member is connected to a bearing 25.
The shaft end portion 24 of the rotating shaft 24
a is located in a sealed chamber, and here, by making the shape of the shaft end portion 24a substantially truncated conical, contact between the electrorheological fluid 26 sealed in the sealed chamber and the shaft end portion 24a is prevented. The area is sufficiently large.

Further, in this example, the electrode attached to the fixing member 21 via the insulating material 27 and in contact with the electrorheological fluid 26 is the positive electrode 28, and the entire support member is the negative electrode. Therefore, according to this assembly structure, the rotating shaft 24 also functions as a negative electrode via the bearing 25. Here, it is also possible to make only the rotating shaft 24, especially its shaft end portion 24a, function as a negative electrode. Also in this damper, by placing the electrorheological fluid 26 in the presence of an electric field, the electrorheological fluid 26 is
With this, the relative displacement of the rotating shaft 24 with respect to the support member can be effectively restrained, so when positioning and stopping the rotating shaft 24, by applying a voltage to the electrode,
The torsional vibration of the rotating shaft 24 due to inertial force can be stopped in an extremely short time.

On the other hand, when the voltage application to the electrodes is stopped and the electric field between the electrodes is extinguished, the viscosity of the electrorheological fluid 26 becomes the minimum value, so that the rotational drive of the rotating shaft 24 is In this case, the driving energy can be made sufficiently small by removing the electric field between the electrodes.

[0021]

Thus, according to the present invention, the movable member can be moved to a predetermined position without increasing the driving energy required to rotate or rotate the movable member.
It is possible to position and stop in an extremely short time,
Therefore, both the drive efficiency of the movable member and the work efficiency of the work using the movable member can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the invention.

FIG. 2 is a graph showing a vibration damping curve.

FIG. 3 is a longitudinal sectional view showing another embodiment of the invention.

FIG. 4 is a longitudinal sectional view showing still another embodiment of the invention.

FIG. 5 is a graph showing a conventional vibration damping curve.

[Explanation of symbols] 1 Fixed axis 2 Rotating arm 3, 25 Bearing 4, 11, 12 Sleeve 5, 13 Annular groove 7, 15, 23 Closed room 8, 26 Electrorheological fluid 9, 28 Positive electrode 14 Cylindrical insulation material 21 Fixed plate 22 Housing member 24 Rotation axis 24a Shaft end part 27 Insulating material

Claims (2)

[Claims] 1. A device comprising a support member and a movable member that rotates or rotates with respect to the support member, and an electrorheological fluid is sealed in a sealed space formed between the support member and the movable member. A variable damping force damper is provided with electrodes on each of the supporting member side and the movable member side of the sealed space. 2. A support member and a movable member that rotates or rotates with respect to the support member, and an end portion or an intermediate portion of the movable member is placed in a closed space defined by the support member. A variable damping force damper is provided with electrodes on the support member side or on the support member side and the movable member side of the closed space.