JPH0356680Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention utilizes the elastic deformation of an elastic body to store energy, strain a part of the elastic body by a large fixed amount, and gradually expand the strain area. The present invention relates to an energy storage device that is compact and lightweight.

[Conventional technology]

An energy storage device that stores energy using elastic deformation of an elastic body is disclosed in Japanese Patent Laid-Open No. 49-96144. The device disclosed in this publication has two drums, and consists of a device in which an elastic body is stretched around the two drums, and the two drums rotate in the same direction. FIG. 4 shows a device in which two drums 10 and 12 having different diameters are arranged side by side, although the device is not disclosed in Japanese Patent Application Laid-open No. 49-96144, but in comparison with the present invention having three or more drums, which will be described later. An energy storage device is shown in which a string-like elastic body 14 is strung across the body.

In the energy storage device shown in JP-A-49-96144 and the energy storage device having two drums shown in FIG. 4, if the initial strain η of the elastic body wound around the small diameter drum is 0, then
The energy at the time of output is 0, and the efficiency is 0%. (The reason will be explained later.) Therefore, if an elastic body with low elastic elongation is used, a sufficient initial strain cannot be applied, so the problem is that the energy at the time of output becomes almost 0. It was hot.

In order to solve this problem, the applicant first
This is a method of distorting a part of an elastic body by a large fixed amount and gradually expanding the area.At the same time, it is possible to efficiently input and output energy even when the initial strain of an elastic body with low elastic elongation is 0 when wrapped around a small diameter drum. A possible energy storage device has been provided (Special Request
61-168033).

The energy storage device of patent application No. 61-168033 is
(a) juxtaposed to each other and rotatable about an axis;
(b) a third drum comprising a first drum, a second drum and an intermediate drum disposed between the first drum and the second drum; and (b) a first drum wound around the first drum. a second part that is wound around a second drum, a third part that is wound around a third drum, and a fourth part that connects each drum; (c) a string-like elastic body having an end fixed to a first drum and an end of a second portion fixed to the second drum; (c) a first drum, a second drum, and a third drum; The amount of rotation of the outer circumference of the second drum is greater than the amount of rotation of the outer circumference of the third drum, and the amount of rotation of the outer circumference of the third drum is greater than that of the first drum. and means for connecting the outer peripheral rotation amount so that the amount of rotation is greater than the amount of rotation of the outer circumference.

[Problem that the invention attempts to solve]

The proposal has shown that the use of multiple drums increases the efficiency of the system as the number of drums increases. However, as the number of drums increases, the weight increases, and when mounted on a vehicle or the like, there is a problem in that the efficiency of the entire system decreases.

The object of the present invention is to make the energy storage device of the type disclosed in Japanese Patent Application No. 168033/1980 more compact and lightweight.

[Means for solving problems]

To achieve the above object, the energy storage device according to the present invention includes a first drum and a second drum, and a first drum and a second drum, which are arranged in parallel with each other and are rotatable around an axis. a third drum comprising at least one intermediate drum disposed between; a first portion wound around the first drum; and a second portion wound around the second drum. , having a third part wound around the third drum and a fourth part connecting each drum, an end of the first part being fixed to the first drum, and a fourth part connecting each drum. a string-shaped elastic body having two ends fixed to the second drum; and a means for connecting the third drum so that the outer circumferential rotation amount of the third drum is larger than the outer circumferential rotation amount of the first drum; The energy storage device comprises a third drum which is movable in the axial direction.

[Effect]

In the above energy storage device of the present invention,
During energy storage, the first part of the elastic body
The amount of wrapping of the second portion of the elastic body around the drum decreases, and the amount of wrapping of the second portion of the elastic body around the second drum increases. At the time of energy release, the amount of wrapping of the second portion of the elastic body around the second drum decreases, and the amount of wrapping of the first portion of the elastic body around the first drum increases. The amount of winding on the third drum does not change, and only the winding position moves on the drum in accordance with the accumulation and release of energy.

During energy storage, when the elastic body is wound around the second drum from the first drum through the third drum, the amount of outer circumferential rotation of the third drum is greater than the amount of outer circumferential rotation of the first drum. Since the amount of outer circumferential rotation of the second drum is larger than the amount of outer circumferential rotation of the third drum, the fourth portion of the elastic body connecting the drums is stretched, and tension is generated in this fourth portion. energy is accumulated, and the wire is wound around the third drum with tensile strain. Next, the fourth portion connecting the third drum and the second drum is further stretched, the strain in this portion increases, and the fourth portion is wound around the second drum with increased energy. Since there is almost no slip between the elastic body and the first drum, second drum, and third drum, the part that causes tensile strain due to drum rotation is mostly the fourth drum that connects the elastic body drums. After a tensile strain occurs, it is maintained in that state and is wound around the second drum via the third drum, where energy is stored.

At the time of energy output, the opposite action to that at the time of storage occurs, and when the elastic body wrapped around the second drum in a state of large tensile strain is wound around the third drum, the outer circumferential rotation of the second drum and the third drum is caused. It is wound around the third drum with the tensile strain reduced by an amount corresponding to the difference in amount. Subsequently, the tensile strain of the elastic body that leaves the third drum decreases by an amount corresponding to the difference in the amount of outer circumferential rotation between the third drum and the first drum, and becomes the same as the initial strain. It is wound up on a drum.
At this time, assuming that there is no third drum, the strain of the elastic body connecting the second drum and the first drum will be equal to the initial strain, and if the initial strain is 0 or close to 0, the energy output will be 0. Or almost 0
The state will be as follows. However, because this third drum is located between the second drum and the first drum, the strain in the elastic body between the third drum and the second drum is greater than the initial strain. Therefore, even if the initial strain of the elastic body is 0, that is, even if an elastic body with low elastic elongation is used, energy can be extracted efficiently.

In the above, the third drum consisting of the intermediate drum rotates integrally with the shaft in the rotational direction, but is movable relative to the shaft in the axial direction, so the third drum is moved by the tension of the elastic body. This eliminates the need for the third drum to have the same overall length as the first and second drums, allowing it to be shortened in the axial direction, making the system smaller and lighter. The aim is to improve the energy efficiency per unit weight of the device.

In a system where the total number of drums is n, a maximum of n-2 axially movable drums can be installed, resulting in a significant weight reduction.

Further, by reducing the number of teeth of the gear attached to the intermediate drum, the rotation speed of the intermediate drum can be increased, and as a result, the diameter of the intermediate drum can be reduced. Therefore, it is possible to further reduce weight and space.

〔Example〕

Preferred embodiments of the energy storage device according to the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention, and FIG. 5 shows its characteristics. In the figure, the energy storage device 20 includes a first drum 22, a second drum 24, and a first drum 22 and a second drum 24, which are arranged in parallel with each other and are rotatable about their respective axes and have different diameters.
between the first drum 22 and the second drum 24, at least one third drum having a diameter intermediate the diameters of the two drums.
drum (intermediate drum) 23. The third drum 23 is movable in the axial direction, but rotates integrally with the shaft in the rotational direction. first drum 2
A string-like elastic body 25 is spirally wound around the second drum 2 and the second drum 24 via the third drum 23.

The elastic body 25 has a first portion 25a that is spirally wound in close contact with the first drum 22.
A second portion 25e is attached to the second drum 24 and wound in a spiral shape, and the second portion 25e is wound around the third drum 23 between the first drum 22 and the second drum 24 once or twice. third part 25
c, and fourth portions 25b and 25d that connect between each drum. The first part 25a, the fourth part 25b, the third part 25c, the fourth part 25d, and the second part 25e are connected in series in the order of 25a, 25b, 25c, 25d, and 25e. continuous in shape. An end 25a' of the first part 25a is fixed to the first drum 22, and an end 25e' of the second part 25e is fixed to the second drum 24.

The first drum 22, the second drum 24 and the third drum
drums 23 are connected via means 28. The means 28 connects the first drum 22, the third drum 23 and the second drum 24 to the second drum 2.
4 (the circumferential movement distance of an arbitrary point located on the outer periphery during drum rotation is defined as the outer periphery rotation amount) is larger than the outer periphery rotation amount of the third drum 23, and the third drum 23 The outer peripheral rotation amount is the first
so that the amount of rotation of the outer periphery of the drum 22 is greater than that of the drum 22.
They are mechanically connected to each other. In this case, when energy is stored, the amount of wrapping of the elastic body 25 on the second drum 24 increases and the amount of the elastic body 25 wrapped around the second drum 24 increases.
The amount of winding on the third drum 23 decreases, the amount of winding on the third drum 23 does not change, and only the winding position of the elastic body 25 changes. When energy is released, elastic body 2
The amount of winding on the first drum 22 of No. 5 increases, and the amount of winding on the second drum 24 decreases.

The main parts have been described above, and the detailed technical explanation of the configuration is as follows. Elastic body 25
The first portion 25a of the elastic body 25 is in direct contact with the outer periphery of the first drum 22, and the second portion 25a of the elastic body 25 is in direct contact with the outer periphery of the first drum 22.
e is in direct contact with the outer periphery of the second drum 24. Further, the third portion 25c is also connected to the third drum 23.
are in direct contact with. Therefore, a frictional force acts between the elastic body 25 and the first drum 22, second drum 24, and third drum 23 to prevent relative displacement in the circumferential direction, and the fourth portion 25b of the elastic body 25 ,25
Even if elongation occurs in d, the tensile strain is the elastic body 25
does not propagate over the entire length of , and almost the fourth part 2
It is limited to only 5b and 25d. The direction in which the first portion 25a of the elastic body 25 is wound around the first drum 22, and the direction in which the third portion 25c of the elastic body 25 is wound around the first drum 22.
The winding directions on the drum 23 are opposite to each other as shown in FIGS. 1 and 2. Also, the winding direction of the third portion 25c of the elastic body 25 and the winding direction of the second portion 25e of the elastic body 25 are
The winding directions are opposite to each other. Also,
The first drum 22, the third drum 23, and the second drum 24 are connected by means 28 so as to rotate in opposite directions one after another at a constant rotation rate. Fourth portions 25b, 25d of elastic body 25
runs through the space between each drum.

In FIG. 2, when a tension force F is applied on the second drum 24 during energy storage, the first drum 22 and the third drum 23, connected by means 28, rotate in the direction of the arrow. At this time, the first drum 22
The radius of the third drum 23 is R1, the radius of the third drum 23 is R2, the radius of the second drum 24 is R3, the number of teeth of each gear of the means 28 is the same, and the relationship is R1<R2<R3, and the amount of outer rotation is When increasing in the order of the first drum 22, the third drum 23, and the second drum 24, the tensile stress of the fourth portions 25b and 25d of the elastic body 25 increases in accordance with the difference in the amount of rotation of the outer circumference. Here, if the elastic body 25 is wound around the first drum 22 with an initial strain η, the fourth portions 25b and 25
The respective tensions F1 and F2 of d are calculated according to Hook's law, and where E is the Young's modulus of the elastic body 25, F1={(1+η)R2−R1}E/R1, F2=
{(1+η)R3−R1}E/R1. Also, the second
The balance of forces on the drum 24 is F=F1・
(R2−R1)/R3+F2・(R3−R2)/R3, so the force Fin during energy storage is Fin=[{(1+η)R2−R1}/R1]・E・{(R2−
R1)/R3}+[{(1+η)R3−R1}/R1]・E・
{(R3−R2)/R3}. With this force F, the elastic body 25 moves from the first drum 25 to the second drum 2.
Energy is accumulated sequentially to 4.

Although the number of intermediate drums 23 is one in the illustrated example, it may be a combination of a plurality of drums arranged side by side. Further, in the figure, 26 indicates a bearing that rotatably supports the drum, and 27 and 29 indicate support stands that support the drum.

The third drum 23, which is an intermediate drum, has a width across flats 31 of a shaft 30, as shown in FIGS. 3 and 4.
The shaft 30 is supported by a roller bearing 32, so that it is mounted integrally with the shaft 30 in the rotational direction and movable in the axial direction. The axial length of the third drum 23 is the same as that of the first drum 22 and the second drum 2.
4, and is moved in the axial direction by the tension of the elastic body 25.

Next, when energy is released, an action opposite to that during storage occurs, and each drum rotates in the opposite direction, and the third drum 23 moves in the opposite direction to the above, and the tensile strain becomes {(1+η)R3−R1}/ In the R1 state, the elastic body 25 wound around the second drum 24 is
When it is wound around the third drum, it enters the third drum 23 with tensile strain reduced by an amount corresponding to the difference in the amount of outer circumferential rotation between the second drum 24 and the third drum 23. Subsequently, the tensile strain of the elastic body 25 coming out of the third drum 23 is reduced by an amount corresponding to the difference in the amount of outer circumferential rotation between the third drum 23 and the first drum 22, and the elastic body 25 becomes the first drum 22. It is wound up. At this time, the respective tensions F1 and F2 of the fourth portions 25b and 25d are F2=[{(1+η)R2−R1}/R1]・E F1=η・E, which causes the second drum 24 to rotate. ForceFout
is, Fout=[{(1+η)R2−R1}/R1]・E・{(R3
−R2)/R3}+η・E・{(R2−R1)/
R3}. Therefore, the efficiency is Fin/Fout, and the calculation result is shown in FIG.

In addition, in the device shown in JP-A-49-96144 and the energy storage device of the comparative example shown in FIG. 6, the force balance on R2 in FIG. 6 is F=F1
It is given by {1-(R1/R2)}, and the magnitude of F1 at the time of input is F1 = E, where η is the initial strain of the elastic body wrapped around the small diameter drum, and Young's modulus is E.
It is given by {(1+η)R2/R1-1}. on the other hand,
The output size is F1=Eη, and its efficiency is {η(1−R1/R2)}/[{(1+η)R2/R1
-1}(1-R1/R2)]. Therefore, for example, if the initial strain η of the elastic body wound around the small diameter drum is 0, the output will be 0 and the efficiency will be 0%. The results of this calculation are shown in FIG. As described above, the energy storage device 20 of the present invention has a greatly improved efficiency and a small initial strain in the elastic body 25 compared to the conventional system shown in Japanese Patent Application Laid-Open No. 49-96144 and FIG. High efficiency can be obtained even under low conditions.

The above is an example in which the amount of rotation of the outer periphery of each drum is changed depending on the rotation radius of each drum, but it is also possible to keep the drum diameter the same and change the amount of rotation of the outer periphery of the drum depending on the gear ratio, and this selection is arbitrary. .

Further, since the third drum 23 is made axially movable and automatically moved in the axial direction by the tension of the elastic body 25, the length of the third drum 23 can be reduced and the device can be improved. It is designed to be more compact and lightweight. In addition, by reducing the number of teeth of the gear of the third drum 23, the third drum 23 can be
Further weight reduction can be achieved by increasing the number of rotations of the third drum 23 and decreasing the diameter of the third drum 23.

[Effect of idea]

When using the energy storage device 20 according to the present invention, the following effects can be obtained.

(a) JP-A-49-96144 and Comparative Example No. 6
Compared to the two-drum system shown in the figure,
By providing the intermediate drum 23, an output can be obtained even when the initial strain of the elastic body 25 is zero, and high efficiency can be expected.

(b) Efficiency can be further improved by increasing the number of intermediate drums 23.

(c) Since the third drum is made movable in the axial direction, the third drum can be made smaller and the apparatus can be made smaller and lighter.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an energy storage device according to an embodiment of the present invention, Fig. 2 is a sectional view of the device shown in Fig. 1, Fig. 3 is a sectional view of the shaft support of the third drum, and Fig. 4. is a sectional view taken in the direction orthogonal to FIG. 3, FIG. 5 is a characteristic diagram of the device shown in FIGS. 1 to 4, and FIG. Cross-sectional view of a comparative example with a drum system, No. 7
The figure is a characteristic diagram of the device of FIG. 6. 20... Energy storage device, 22... First drum, 23... Third drum (intermediate drum),
24... Second drum, 25... Elastic body, 25a
...First part, 25b...Fourth part, 25c
...Third part, 25d...Fourth part, 25e
...Second part, 30...Third drum shaft, 3
2...Bearing.

Claims (1)

[Scope of utility model registration request] A first drum and a second drum, juxtaposed to each other and rotatable about their axes, and at least one intermediate drum arranged between the first drum and the second drum. No. 3 drum; a first portion wound around the first drum; a second portion wound around the second drum;
It has a third part that is wound around the third drum, and a fourth part that connects the drums, an end of the first part is fixed to the first drum, and a fourth part that connects the drums. a string-like elastic body, the end of which is fixed to the second drum; the first drum, the second drum, and the third drum; and a means for connecting the third drum so that the outer circumferential rotation amount of the third drum is greater than the outer circumferential rotation amount of the first drum; An energy storage device comprising a third drum which is axially movable.