JPS61184264A - displacement converter - Google Patents

Abstract

PURPOSE:To generate satisfactory rotational torque by providing an eccentric means in a rotational displacement converting section, which means varies the converting ratio of converting straight line motion to rotational motion with rotational angle. CONSTITUTION:Ropes 3, 4 are respectively connected to movable ends of artificial rubber muscles 1.2, wound around groove portions of spiral pulleys 5A-1, 5A-2 having large radius of curvature from spiral groove portions having small radius of curvature and then connected to the ends 9, 10 of arms 8. the increase and decrease of rotational torque due to the variation of contractive force are offset by the difference between the respective products of the contractive forces of artificial rubber muscles 1, 2 and those of pulley. Thus, the reduction of contractive force is compensated so that satisfactory rotational torque can be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a displacement converting device, and in particular to a flexible actuator that expands in the radial direction and contracts in the length direction by the inflow of pressure fluid, e.g. The present invention relates to a displacement conversion device suitable for converting linear displacement of a rubber artificial muscle into rotational displacement.

[Background of the invention]

Conventionally, there are various types of displacement conversion devices that convert linear displacement into rotational displacement, and one of them is, for example, a pair of direct-acting actuators and a device at each moving end of the pair of direct-acting actuators. and a connected rotational displacement converter.

This rotational displacement converter is composed of, for example, a pulley and a wire rope wrapped around the pulley and connected to each moving end of a pair of direct-acting actuators, and the direct-acting actuators include rubber artificial muscles. There is.

This rubber artificial muscle has the characteristic of expanding in the radial direction and contracting in the length direction as the pressure fluid supplied therein rises.

Figure 13 is a characteristic diagram of the rubber artificial muscle actuator, and the relationship between the contraction rate ε and contraction force F of the rubber artificial muscle with respect to the internal pressure P of the pressure fluid supplied inside has the tendency as shown in the figure. There is.

This rubber artificial muscle is disclosed in ``Rubber artificial muscle production notes'' written by Shigeru Matsushita in ``Measurement and Control'' (Volume 7, No. 12) published in December 1961.

An example of a schematic structure of a displacement converting device of the type described above will be explained with reference to FIGS. 14 to 16.

FIG. 14 is a schematic configuration diagram of a conventional displacement converting device, and FIG.
16 is a perspective view showing details of the rotational displacement converter of the device shown in FIG. 14.

In FIG. 14, reference numerals 1 and 2 refer to rubber artificial muscles associated with a pair of flexible actuators that expand and contract due to the inflow and outflow of pressure fluid, one end of which is fixed, and the other end of which moves linearly. It is a moving end. Reference numerals 3 and 4 denote wire ropes (hereinafter simply referred to as 口) connected to each moving end of the rubber artificial muscles 1 and 2.

5-1 and 5-2 are pulleys around which the ropes 3 and 4 are wound; 6 is a support; 7 is a shaft connected to a pulley shaft attached to the tip of the support 6; 8 rotates around the shaft 7; The handle arm 11 is a hand for gripping an article.

As shown in Fig. 14.16, the ropes 3 and 4 are wound around the pulleys 5-1 and 5-2 rotating around the shaft 7 once or multiple times (one wrap in Fig. 16), respectively. , are connected to the ends 9 and 10 of the arm 8, and the hand 1 is connected to the ends 9 and 10 of the arm 8, and the hand 1 is
1 is rotated.

That is, the rubber artificial muscles 1 and 2 function as linear actuators that provide linear motion, and the pulleys 5-1, 5-2,
The ropes 3, 4, shaft 7, etc. constitute a rotational displacement converter for converting the linear motion of the rubber artificial muscles 1, 2 into the rotational motion of the arm 8 and hand 11.

In FIG. 14, the characteristics of the rubber artificial muscles 1 and 2 are assumed to be equal, and a neutral state in which the internal pressure due to the pressure fluid is equal is shown.

FIG. 15 shows the operating state, in which the internal pressure of the rubber artificial muscle 2 is increased and the internal pressure of the rubber artificial muscle 1 is decreased. The rubber artificial muscle 2 expands in the radial direction and contracts in the length direction, while the rubber artificial muscle 1 contracts in the radial direction and stretches in the length direction, so the ropes 3 and 4 move in the direction of the arrow and the pulley 5-1.5-2 rotates as shown by the rotation arrow to rotationally displace the handle 11 as shown in FIG.

In such a conventional displacement converting device, the rotational torque is determined by the difference in driving force between the pair of rubber artificial muscles 1 and 2, and the pulley 5.
(generic term for 5-1 and 5-2) is uniquely determined by multiplying by the radius.

In particular, in the case of rubber artificial muscles, as shown in FIG. 13, as the contraction rate ε increases, the contraction rate F decreases, so as the rotation angle of the arm 8 increases from the neutral state, the rotational torque decreases rapidly. There was a problem.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems in the conventional technology, and its purpose is to provide a displacement conversion device that can compensate for the reduction in contraction force in a flexible actuator and generate good rotational torque. There is.

[Summary of the invention]

The configuration of the displacement converting device according to the present invention includes a pair of flexible actuators that expand and contract due to the inflow and outflow of pressure fluid;
In a displacement converting device comprising a rotational displacement converting section that converts linear motion caused by expansion and contraction of the pair of actuators into rotational motion, the rotational displacement converting section has a conversion rate for converting linear motion into rotational motion depending on the rotation angle. It is equipped with variable eccentricity means.

[Embodiments of the invention]

Hereinafter, each embodiment of the present invention will be described with reference to each of FIGS. 1 to 12.

First, FIG. 1 is a schematic configuration diagram of a displacement converting device according to an embodiment of the present invention, FIG. 2 is a diagram of its operating state, and FIG.
FIG. 2 is a perspective exploded view showing details of the rotational displacement converter shown in FIG. 1; In the drawings, the same reference numerals as those in FIGS. 14 to 16 are the same parts as in the prior art, so the explanation thereof will be omitted.

In the embodiment shown in FIGS. 1 to 3, the difference from the prior art shown in FIGS. 14 to 16 is the structure of the pulley, which is a main component of the rotational displacement converter, and FIG. 3 shows the details thereof.

As shown in FIG. 3, the arm 8 is fixed at a shaft 7 related to the pulley shaft so as to grip the pulleys 5A-1 and 5A-2 using a gripping portion 8a. Furthermore, the grip portion 8 of the arm 8
The gripping portions 6a of the support columns 6 are combined so as to sandwich the shaft 7a, and the shaft 7 is supported by the bearings 13 and 14 thereof.

The pulleys 15A-1 and 15A-2 are helical pulleys with a radius of curvature that increases in a spiral manner, and each has a spiral groove portion on the side surface that is mirror-symmetrical with respect to the center plane perpendicular to the axis 7. It is.

As is clear from FIGS. 1 to 3, the ropes 3 and 4 are connected to the moving ends of the rubber artificial muscles 1 and 2, respectively, and are connected to the helical grooves of the helical pulleys 5A-1 and 5A-2 with a small radius of curvature. After being wound around the groove portion having a large radius of curvature, it is connected to the tips 9 and 10 of the arm 8. 15.16 is
This is a stopper that prevents the ropes 3 and 4 from coming off the helical pulleys 5A-1 and 5A-2.

FIG. 2 shows an example of the operating state of the displacement converting device of this embodiment, in which the rubber artificial muscle 1 contracts in the radial direction and extends in the length direction, and the rubber artificial muscle 2 conversely extends in the radial direction. The figure shows the case where it expands and shortens in the length direction.

At this time, the rope 3 connected to the moving end of the rubber artificial muscle 1
Rubber artificial muscle 1 of spiral pulley 5A-1 wrapped around
The radius of curvature on the side decreases, and conversely the helical pulley 5A- around which the rope 4 connected to the moving end of the rubber artificial muscle 2 is wound.
The radius of curvature of the rubber artificial muscle 2 side increases.

In other words, the rotational torque is the difference between the contractile force of the pair of rubber artificial muscles 1°2 and the product of each of the spiral pulleys 5A-1 and 5A-2, so the rotational torque is the difference between the contractile force of the pair of rubber artificial muscles 1.2 and the product of each of the spiral pulleys 5A-1 and 5A-2. Increases and decreases in rotational torque due to fluctuations in F (see FIG. 13) are reduced or canceled out.

Here, the relationship between the rotation angle and the radius of curvature of the spiral pulleys 5A-1 and 5A-2 may be appropriately set in consideration of the characteristics of the rubber artificial muscles 1 and 2.

According to this embodiment, the relative eccentricity between the pulley and the rope, which are the main components of the rotational displacement converter, in other words, the conversion rate for converting linear motion into rotational motion is variable depending on the rotation angle. This has the effect of compensating for the reduction in the contractile force of the rubber artificial muscle and generating good rotational torque.

Next, another embodiment of the present invention will be described with reference to FIGS. 4 to 6.

Here, FIG. 4 is a schematic configuration diagram of a displacement converter according to another embodiment of the present invention, FIG. 5 is a diagram of its operating state, and FIG. 6 is a detailed diagram of the rotational displacement converter of FIG. 4. FIG. In the figure, the same reference numerals as those in FIG. 1 are the same parts as in the previous embodiment, so the explanation thereof will be omitted.

The embodiment shown in FIGS. 4 to 6 differs from the embodiment shown in FIGS. 1 to 3 in the pulley and the way the rope is hung, the details of which are shown in FIG.

5B is one helical pulley, which has a spiral groove portion on both sides that is mirror-symmetrical with respect to the central plane perpendicular to the axis 7.

A shaft 7 and an arm 8 are fixed to this helical pulley 5B, and the gripping portion 6a of the support column 6 is attached to grip the helical pulley 5B, and the shaft 7 is supported by its bearing portion 13.14. There is.

One end of the rope 20 is connected to the moving end of the rubber artificial muscle 1, and the rope 20 is wound from the helical groove part with a small radius of curvature of the helical pulley 5B to the pulley groove part with a large radius of curvature, and then the rope 20 is wound around the helical groove part of the helical pulley 5B with a small radius of curvature. It is then connected to the moving end of the rubber artificial muscle 2. 17 is a stopper that fixes the rope 20 to the spiral pulley 5B.

FIG. 5 is a diagram showing an example of the operating state, and the mechanical relationship established between the rubber artificial muscle and the spiral boot is exactly the same as the state shown in FIG. 2 above.

As described above, according to the embodiments shown in FIGS. 4 to 6, the same effects as those of the embodiments shown in FIGS. 1 to 3 can be expected.

Next, still another embodiment of the present invention will be described with reference to FIGS. 7 to 9.

Here, FIG. 7 is a schematic configuration diagram of a displacement knee conversion device according to yet another embodiment of the present invention, FIG. 8 is a diagram of its operating state, and FIG. 9 is a rotational displacement conversion unit of FIG. 7. FIG. In the figure, the same numbers as in Figure 1 are numbered 1 to 3.
Since it is the same part as the embodiment shown in the figure, its explanation will be omitted.

゛ The embodiment shown in Figs. 7 to 9 differs from the embodiment shown in Figs. 1 to 3 in the structure of the pulley, the details of which are shown in Fig. 9.

5C-1 and 5C-2 are eccentric pulleys whose pulley axes are at eccentric positions, and the way the ropes 3 and 4 are hung is similar to the prior art or the embodiment shown in FIGS. 1 to 3.

FIG. 8 shows an example of the operating state, in which the rubber artificial muscle 1 contracts in the radial direction and extends in the length direction, and the rubber artificial muscle 2 conversely expands in the radial direction and extends in the length direction. This shows the case shortened to .

At this time, the rope 3 connected to the moving end of the rubber artificial muscle 1
The wrapped part of the rope 4 is on the short diameter side from the pulley axis, and conversely, the wrapped part of the rope 4 connected to the moving end of the rubber artificial muscle 2 is on the long diameter side from the pulley axis, and consists of the rubber artificial muscle and the pulley. The mechanical relationship is the same as in FIG.

As described above, the embodiment shown in FIGS. 7 to 9 is expected to have the same effects as the embodiment shown in FIGS. 1 to 3, and is particularly effective when the swing angle of the arm 8 is within ±90 degrees.

Next, still other embodiments of the present invention will be described in FIGS. 10 to 1.
This will be explained with reference to FIG.

Here, FIG. 10 is a schematic configuration diagram of a displacement converter according to still another embodiment of the present invention, FIG. 11 is a diagram of its operating state, and FIG. 12 is a diagram of the rotational displacement converter of FIG. 10. It is a perspective view showing details. In the figure, the same numbers as in Fig. 4 are
Since the parts are the same as those in the embodiment shown in FIGS.

The embodiment shown in FIGS. 10 to 12 differs from the embodiment shown in FIGS. 4 to 6 in the structure of the pulley, the details of which are shown in FIG. 12.

5D is one eccentric pulley whose pulley axis is at an eccentric position, and the rope 21 is connected to the moving end of the rubber artificial muscle 1, and after being wound around the eccentric pulley 5D, the rope 21 is attached to the rubber artificial muscle 2.
connected to the moving end of the

17 is a stopper that fixes the rope 21 to the eccentric pulley 5D.

FIG. 11 shows an example of the operating state, and the mechanical relationship established between the rubber artificial muscle and the pulley is the same as that in FIG. 5 or the previous FIG. 8.

As described above, according to the embodiment shown in FIGS. 10 to 12, the fourth to sixth
The same effects as the embodiment shown in the figure can be expected, especially in the seventh to
Similar to the embodiment shown in FIG. 9, this is effective when the swing angle of the arm 8 is within ±90°.

In addition, in the above embodiment, an example was explained in which a rubber artificial muscle was used as a direct-acting actuator, but the present invention is not limited to this, and may be applied to other flexible actuators that are expected to have similar effects. Does not hinder recruitment.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a displacement conversion device that can compensate for the reduction in contraction force in a flexible actuator and generate good rotational torque.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a displacement converter according to an embodiment of the present invention, FIG. 2 is a diagram of its operating state, and FIG. 3 is a perspective view showing details of the rotational displacement converter of FIG. 1. The exploded view, Figure 4, is
A schematic configuration diagram of a displacement converting device according to another embodiment of the present invention,
FIG. 5 is a diagram of its operating state, FIG. 6 is a perspective exploded view showing details of the rotational displacement converter shown in FIG. 4, and FIG. 7 is a diagram of a displacement converter according to still another embodiment of the present invention. FIG. 8 is a schematic configuration diagram, FIG. 8 is a diagram of its operating state, FIG. 9 is a perspective view showing details of the rotational displacement converter of FIG. 7, and FIG. 10 is a diagram according to still another embodiment of the present invention. Schematic configuration diagram of displacement converting device, 11th
12 is a perspective view showing details of the rotational displacement converter shown in FIG. 10, FIG. 13 is a characteristic diagram of the rubber artificial muscle actuator, and FIG. 14 is a conventional displacement converter. 15 is a schematic configuration diagram of the system, and FIG.
14 is a perspective view showing details of the rotational displacement converter of the apparatus shown in FIG. 14. 1.2...Rubber artificial muscle, 3,4...Rope, 5A-
1゜5A-2,5B...Spiral pulley, 5cm1.5
C-2, 5D... Eccentric pulley, 6... Support column, 7...
・Axis, 8... Arm, 11... Hand, 20, 21
．． ···rope. 1st dream 2 Figure 7th circle δ l

Claims (1)

[Claims] 1. A device comprising: a pair of flexible actuators that expand and contract due to the inflow and outflow of pressure fluid; and a rotational displacement converter that converts linear motion caused by the expansion and contraction of the pair of actuators into rotational motion. 1. A displacement converting device, wherein the rotational displacement converting section is provided with an eccentric means whose conversion rate for converting linear motion into rotational motion is variable depending on the rotation angle. 2. In the device described in claim 1, the eccentric means includes a helical pulley having a helical groove whose radius of curvature increases in reverse mirror symmetry with respect to a plane perpendicular to the pulley axis; A displacement converting device comprising a rope that is wrapped around one or more times and connected to each moving end of a pair of flexible actuators. 3. In the device described in claim 1, the eccentric means includes an eccentric pulley whose pulley shaft center is at an eccentric position, and is wound around the eccentric pulley once or multiple times to each moving end of the pair of flexible actuators. A displacement conversion device consisting of a rope connected to the