Mechanical energy storage device

Abstract

To provide a mechanical power storage device capable of stabilizing power generation by suppressing fluctuation of generated torque even if thrust changes with a stroke change of an elastic body.SOLUTION: The mechanical power storage device 1 stores power by extending a coil spring 2 (elastic body) by traction by winding of a wire rope 3 (rope-like body) to convert the energy into physical energy, and generates power by kinetic energy when the coil spring 2 is released and restored to an initial state. A guide groove (11) for spirally guiding the wire rope (3) is formed on a tapered surface of the drum (6), and a diameter change due to winding of the drum (6) is made to correspond to a stroke change of the coil spring (2) with a large diameter side of the drum (6) as a winding start side and a small diameter side of the drum (6) as a winding end side, so that a fluctuation in generated torque can be suppressed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mechanical electricity storage device. [Background technology]

[0002] In recent years, research and development into renewable energy sources such as sunlight, wind, and biomass fuels has been progressing. However, this type of renewable energy is known to have large fluctuations when output as electricity via generators, etc., and does not necessarily correspond to electricity demand. Therefore, it is essential to take some measures to temporarily store surplus electricity during periods of low demand.

[0003] Until now, when such temporary storage of electricity was desired, chemical batteries such as lithium ion batteries have been used, and prior art documents relating to the power generation systems using renewable energy as described above, such as Patent Document 1 below, are already well known.

[0004] Chemical batteries such as the aforementioned lithium-ion batteries have problems such as being prone to deterioration in a short period of time and being difficult to recycle after deterioration, and there is a demand for new means of storing electricity that are different from existing chemical batteries.

[0005] More specifically, a mechanical energy storage device is being considered that uses surplus electricity to maintain a resilient body in a compressed or extended state, converts the electricity into physical energy known as the resilience of the resilient body, and temporarily stores it, and then drives a generator with the kinetic energy generated when the resilient body is released and returns to its initial state, thereby enabling electricity to be extracted. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-105667 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in this type of method, in which the spring body is kept compressed or extended and converted into physical energy in the form of the restoring force of the spring body, the thrust force changes as the stroke of the spring body changes due to the influence of the spring constant, resulting in fluctuations in the generated torque and making it difficult to generate stable power.

[0008] The present invention has been made in consideration of the above-mentioned problems, and provides a mechanical energy storage device that can stabilize power generation by suppressing fluctuations in generated torque even when thrust changes due to changes in the stroke of the elastic body. [Means for solving the problem]

[0009] The present invention is a mechanical energy storage device that converts a resilient body into physical energy by stretching or compressing it when a cord-like body is wound up to pull it, thereby storing the energy, and generates electricity from the kinetic energy when the resilient body is released and restored to its initial state.The drum that winds up the cord-like body is formed in a cone shape so that its diameter gradually increases in the axial direction, and a guide groove that guides the cord-like body in a spiral shape is formed on the tapered surface of the drum, with the larger diameter side of the drum being the winding start side and the smaller diameter side being the winding end side, so that the change in diameter due to winding up the drum corresponds to the change in stroke of the resilient body, thereby suppressing fluctuations in the generated torque.

[0010] In this case, when the cord-like body is wound from the large diameter side to the small diameter side of the conical drum and the resilient bodies are held in an extended or compressed state by the traction caused by the winding, electricity is temporarily stored in the form of physical energy converted into the restoring force of the two resilient bodies.When the two resilient bodies are released from this stored state, electricity is generated by the kinetic energy generated when the two resilient bodies return to their initial state, and the stored electricity is extracted.

[0011] At this time, the thrust generated by the spring body decreases based on the spring constant in accordance with the change in stroke as the spring body returns to its initial state.As a result, the cord-like body is unwound from the drum and the unwound position moves axially from the small diameter side to the large diameter side, while the radial distance from the rotating shaft to the unwound position becomes longer, resulting in suppression of fluctuations in the generated torque, which is expressed as the product of this distance and thrust.

[0012] In addition, in the present invention, a system may be adopted in which the resilient body is stretched by pulling the cord-like body when it is wound up, or a system may be adopted in which the resilient body is compressed by pulling the cord-like body when it is wound up.

[0013] Furthermore, in carrying out the present invention more specifically, it is preferable to provide a motor generator connected to the drum via a speed increase / decrease gear so as to be able to transmit torque, and a brake mechanism for locking the shaft rotation of the motor generator. [Effects of the Invention]

[0014] According to the mechanical energy storage device of the present invention, the elastic body, which has been stretched or compressed by the traction caused by winding up the cord-like body, is released, and electricity is generated using the kinetic energy when the elastic body returns to its initial state.When the cord-like body wound around the conical drum is unwound while moving the unwinding position from the small diameter side to the large diameter side, the distance from the rotation axis to the unwinding position can be changed, and fluctuations in the generated torque can be suppressed even if the thrust changes as the stroke of the elastic body changes, thereby achieving the excellent effect of stabilizing power generation and achieving efficient power extraction. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing a first embodiment of the present invention. [Figure 2] 2 is a schematic diagram showing a state in which the wire rope has been wound onto the drum of FIG. 1. FIG. [Figure 3] FIG. 10 is a schematic diagram showing a second embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a state in which the wire rope has been completely wound onto the drum of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0017] Figures 1 and 2 show a first embodiment of the mechanical electricity storage device of the present invention. The mechanical electricity storage device 1 shown here converts a coil spring 2 (spring body) into physical energy by stretching it when a wire rope 3 (cord-like body) is wound up, thereby storing electricity, and generates electricity from the kinetic energy generated when the coil spring 2 is released and restored to its initial state. More specifically, the base end of the coil spring 2 is fixed on a foundation 4, while a drum 6 installed in a building 5 above and spaced apart from the foundation 4 winds up the wire rope 3 connected to the tip of the coil spring 2, thereby pulling the coil spring 2 upward in Figure 1 and stretching it.

[0018] One axial end of the drum 6 is rotatably supported by a plummer 7 (a bearing unit that houses a rolling bearing inside), and the other end is connected to a motor generator 9 via a speed reducer 8 so that torque can be transmitted, and the axial rotation of the motor generator 9 is locked by a brake mechanism 10.

[0019] In this embodiment, the drum 6 that winds the wire rope 3 is formed in a cone shape so that its diameter gradually expands in the axial direction, and a guide groove 11 that guides the wire rope 3 in a spiral is formed on the tapered surface of the drum 6.The larger diameter side of the drum 6 is the winding start side and the smaller diameter side is the winding end side, and the diameter change due to winding of the drum 6 is matched to the stroke change of the coil spring 2, so that fluctuations in the generated torque can be suppressed.

[0020] It should be noted that the illustrations in Figures 1 and 2 are merely schematic illustrations for the convenience of explaining the invention, and the scale of the coil spring 2 and drum 6 does not necessarily correspond to the actual equipment. Furthermore, the drum 6 and coil spring 2 are not limited to being laid out in the vertical direction, and may, for example, be laid out in the horizontal direction.

[0021] In this case, when the motor generator 9 is driven with electricity to wind the wire rope 3 from the large diameter side to the small diameter side of the conical drum 6, and the coil spring 2 is extended upward from the state shown in Figure 1 to the state shown in Figure 2, and the axial rotation of the motor generator 9 is locked by the brake mechanism 10, electricity is temporarily stored in the form of physical energy converted into the restoring force of the coil spring 2, and when the brake mechanism 10 is unlocked from this stored state, the kinetic energy generated when the coil spring 2 is released and restored to its initial state (the state shown in Figure 1) causes the wire rope 3 to be unwound from the drum 6, and the motor generator 9, which is connected to the drum 6 so as to be able to transmit torque via the speed reducer 8, is driven as a generator and electricity is extracted.

[0022] At this time, the thrust generated by the coil spring 2 decreases based on the spring constant in accordance with the change in stroke as the coil spring 2 returns to its initial state.As a result, the wire rope 3 is unwound from the drum 6, and the unwound position moves axially from the small diameter side to the large diameter side, and the radial distance from the rotating axis to the unwound position becomes longer, thereby suppressing the fluctuation in the generated torque, which is expressed as the product of this distance and the thrust.

[0023] Therefore, according to the above embodiment, when the coil spring 2, which has been stretched by the traction caused by winding up the wire rope 3, is released and electricity is generated using the kinetic energy generated when the coil spring 2 returns to its initial state, the wire rope 3 wound around the conical drum 6 can be unwound while moving the unwinding position from the small diameter side to the large diameter side, thereby changing the distance from the rotating axis to the unwinding position, and fluctuations in the generated torque can be suppressed even if the thrust changes with changes in the stroke of the coil spring 2, thereby stabilizing power generation and achieving efficient power extraction.

[0024] Figures 3 and 4 show a second embodiment of the mechanical energy storage device 1 of the present invention, which differs from the first embodiment described above in that it employs a system in which the coil spring 2 is extended by traction caused by winding up the wire rope 3, in this embodiment, it employs a system in which the coil spring 2 is compressed by traction caused by winding up the wire rope 3. More specifically, a cylindrical casing 12 is installed upright directly below a drum 6 installed in an upper building 5, and a slider 13 is housed within the casing 12 so that it can slide freely in the vertical direction. A coil spring 2 that can expand and contract in the vertical direction is housed between the slider 13 and a partition wall 14 fixedly installed near the upper end of the casing 12, and the wire rope 3 connected to the upper end of the slider 13 is passed through an opening 15 in the center of the partition wall 14 and wound up by the upper drum 6, thereby pulling the slider 13 upward in Figure 3 and compressing the coil spring 2 between the partition wall 14.

[0025] Furthermore, the opposing sides of the slider 13 and the partition wall 14 are provided with a convex shape so that they can fit into the end of the coil spring 2 and hold the end, and the body of the slider 13 is fitted with a resin outer skin so that it can slide smoothly with low friction against the inner surface of the casing 12.

[0026] Here, as in the first embodiment, one axial end of the drum 6 is rotatably supported by a plumber 7 (a bearing unit that stores a rolling bearing inside), and the other end is connected to the motor generator 9 via a speed reducer 8 so that torque can be transmitted, and the axial rotation of the motor generator 9 is locked by a brake mechanism 10.In this embodiment, too, the drum 6 is formed in a cone shape so that its diameter gradually increases in the axial direction, and a guide groove 11 that guides the wire rope 3 in a spiral shape is formed on the tapered surface of the drum 6.The larger diameter side of the drum 6 is the winding start side and the smaller diameter side is the winding end side, and the diameter change due to winding of the drum 6 is matched to the stroke change of the coil spring 2, so that fluctuations in the generated torque can be suppressed.

[0027] It should be noted that the illustrations in Figures 3 and 4 are also schematic illustrations for the convenience of explaining the invention, and the scale of the coil spring 2 and drum 6 does not necessarily correspond to that of the actual equipment. Furthermore, the drum 6 and coil spring 2 are not limited to being laid out in a vertical direction, and may, for example, be laid out in a horizontal direction.

[0028] In this case, the motor generator 9 is driven by electricity to wind the wire rope 3 from the large diameter side to the small diameter side of the conical drum 6, and when the slider 13 is pulled upward from the state shown in Figure 3 to the state shown in Figure 4, compressing the coil spring 2 between the partition wall 14, and the axial rotation of the motor generator 9 is locked by the brake mechanism 10, electricity is temporarily stored in the form of physical energy, that is, the restoring force of the coil spring 2, and when the brake mechanism 10 is unlocked from this stored state, the kinetic energy generated when the coil spring 2 is released and restored to its initial state (the state shown in Figure 3) causes the wire rope 3 to be unwound from the drum 6, and the motor generator 9, which is connected to the drum 6 so as to be able to transmit torque via the speed reducer 8, is driven as a generator and electricity is extracted.

[0029] At this time, the thrust generated by the coil spring 2 decreases based on the spring constant in accordance with the change in stroke as the coil spring 2 returns to its initial state.As a result, the wire rope 3 is unwound from the drum 6, and the unwound position moves axially from the small diameter side to the large diameter side, while the radial distance from the rotating axis to the unwound position becomes longer, resulting in suppression of fluctuations in the generated torque, which is expressed as the product of this distance and thrust.

[0030] Therefore, in the above embodiment, when the coil spring 2, which has been compressed by the traction caused by winding up the wire rope 3, is released and electricity is generated using the kinetic energy generated when the coil spring 2 returns to its initial state, the wire rope 3 wound around the conical drum 6 can be unwound while moving the unwinding position from the small diameter side to the large diameter side, thereby changing the distance from the rotating axis to the unwinding position, and fluctuations in the generated torque can be suppressed even if the thrust changes with changes in the stroke of the coil spring 2, thereby stabilizing power generation and achieving efficient power extraction.

[0031] It should be noted that the mechanical energy storage device of the present invention is not limited to the above-described embodiments, and the resilient body may be of a type other than a coil spring, the cord-like body may be of a type other than a wire rope, and various other modifications may of course be made within the scope of the present invention without departing from the spirit of the present invention. [Explanation of symbols]

[0032] 1 Mechanical energy storage device 2 Coil spring (spring) 3 Wire rope (cord) 6 Drums 9 Motor generator 10 Brake mechanism 11 Guide groove

Claims

1. A mechanical electricity storage device that generates electricity by converting a resilient body into physical energy by stretching or compressing it when a cord-like body is wound up to pull it, and then releasing the resilient body to restore it to its initial state and using the kinetic energy generated when that body is restored. The mechanical electricity storage device is characterized in that the drum that winds up the cord-like body is formed in a cone shape so that its diameter gradually increases in the axial direction, and a guide groove that guides the cord-like body in a spiral shape is formed on the tapered surface of the drum, with the larger diameter side of the drum being the winding start side and the smaller diameter side being the winding end side, and the diameter change due to winding up the drum being matched with the stroke change of the resilient body, so that fluctuations in generated torque can be suppressed.

2. 2. A mechanical electricity storage device according to claim 1, wherein the elastic body is extended by being pulled by winding up the cord-like body.

3. 2. A mechanical electricity storage device according to claim 1, wherein the resilient body is compressed by pulling the cord-like body when it is wound up.

4. 4. The mechanical electricity storage device according to claim 1, further comprising: a motor generator connected to the drum via a speed increase / decrease gear so as to be able to transmit torque; and a brake mechanism for locking the shaft rotation of the motor generator.

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