KR101569133B1 - Energy harvesting apparatus for bicycle - Google Patents

Abstract

The present invention relates to an energy harvesting apparatus for a bicycle. According to the present invention, an energy harvesting apparatus for a bicycle comprises: a plurality of spokes lone arranged between a hub which is arranged in the center of a bicycle wheel and a rim to which a vehicle tire is coupled, and formed by a chargeable material; and a charging unit arranged to surround at least one of the spokes, wherein an inner circumferential surface which is in contact with an outer circumferential surface of the spokes is formed by a chargeable material for triboelectrification to be possible in case of being in contact with and separated from an outer circumferential surface of the spokes.

Description

Energy harvesting apparatus for bicycle < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy harvesting apparatus for a bicycle, and more particularly, to an energy harvesting apparatus for a bicycle having an improved structure for efficiently harvesting energy using a bicycle commonly used in everyday life.

Recently, environmental problems such as climate change have attracted attention, and government is promoting low carbon green growth for carbon emission reduction. For example, bicycles are a typical example of low-carbon green transportation. Public bicycles are already installed in many cities. Especially, these public bicycles are equipped with a hub dynamo, which makes it possible to use headlamps through self-generation and adds to the environment-friendly meaning of bicycles.

The hub dynamo, which is mainly mounted on the front wheel hub of a bicycle, is a power generating device that uses electromagnetic induction phenomenon. It has a permanent magnet and does not require a battery. However, the hub dynamo affects the rolling characteristics of the wheels, increasing the user's motion load, reaching the rated output at a constant speed, resulting in maximum efficiency and low efficiency at other speeds. In addition, since the electric power is lower than that of an electric bicycle using a lithium ion battery, its application range is limited. Therefore, it is necessary to develop an energy harvesting device to assist the existing hub dynamo to produce larger and more stable power.

For this additional energy harvest, understanding of the dynamic characteristics of the bike in motion should be prioritized. Due to the characteristics of the bicycle system, the vibration energy generated when traveling on a non-smooth road surface is considerably large, and its direction and size change from time to time. In particular, vibration acceleration values on wheels including bike shock absorbers have been measured up to 8 g, which is a reasonable level for conversion to electrical energy.

Therefore, there is a need to design a device for harvesting energy by applying a random vibration mechanism of such a bicycle to a triboelectric material.

It is an object of the present invention to provide an energy harvesting apparatus for a bicycle which can efficiently harvest energy using dynamic characteristics of a bicycle commonly used in daily life .

According to an aspect of the present invention, there is provided an energy harvesting apparatus for a bicycle, comprising: a plurality of spokes arranged in a lengthwise manner between a hub disposed at a center of a bicycle wheel and a rim to which a bicycle tire is coupled; And at least one inner peripheral surface which is in contact with an outer circumferential surface of the spokes so as to enable friction charging when the outer peripheral surface of the spokes is contacted with and separated from the outer peripheral surfaces of the plurality of spokes, ; And

The charging unit may include a charging unit arranged to surround the spokes and having an inner circumferential surface contacting the outer circumferential surface of the spokes; And a support part having one end connected to one of the hub and the rim and the other end connected to the charging part.

The charging unit may further include a plurality of holes so that external air can be introduced into the charging unit in addition to the through holes through which the spokes are installed.

It is preferable that at least a portion of the spoke connected to the hub is made of the same material as the hub.

The energy harvesting device for a bicycle according to the present invention having the above-described configuration is characterized in that the charging unit is repeatedly tilted with respect to the spoke by vibrations or spokes transmitted to an automobile wheel and resistance by air flowing between the charging units, The energy recovery by the friction charging between the outer circumferential surface of the spoke and the inner circumferential surface of the charging unit becomes possible.

As a result, according to the present invention, a cantilever-shaped charging unit is connected to a hub of a bicycle to enclose an aluminum spoke. By using the air resistance due to the body vibration at the time of road driving and the rotation of the wheel, It is anticipated that the advantage of replacing or supplementing the power generation of the existing hub dynamo in the current situation where the utilization of the bicycle is being increased.

1 is a side view showing a state of use of an energy harvesting apparatus for a bicycle according to an embodiment of the present invention;
Fig. 2 is a partially enlarged view of Fig. 1; Fig.
3 is a sectional view taken along the line III-III of Fig.
4 is an operational state diagram for explaining the triboelectrification principle of the embodiment of the present invention.
FIG. 5 is a reference drawing related to mathematical modeling for selecting a material of a charging unit employed in an embodiment of the present invention. FIG.

Hereinafter, an energy harvesting apparatus for a bicycle according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a side view showing a state of use of an energy harvesting apparatus for a bicycle according to an embodiment of the present invention, FIG. 2 is an enlarged view of part II of FIG. 1, FIG. 3 is a sectional view of III- Is an operational state diagram for explaining the principle of triboelectrification according to one embodiment of the present invention.

As shown in these drawings, the energy harvesting apparatus 100 for a bicycle according to the present invention can be applied to a triboelectric material by applying a random vibration mechanism of a bicycle, which is popularly used in daily life, In particular, by applying a module to a spoke (1) (spoke) of a bicycle wheel, it is designed to sufficiently utilize the vibration due to the road surface and the vibration due to the air resistance. A plurality of spokes (1) ).

Each of the spokes 1 is disposed between a hub disposed at the center of the bicycle wheel and a rim to which the bicycle tire is engaged, and is formed of a chargeable material. For example, the spoke 1 is preferably made of a material such as aluminum alloy which is positively charged.

2 and 3, the charging unit 2 is arranged so as to surround at least one of the plurality of spokes 1, and the inner peripheral surface of the charging unit 2 is in contact with the outer peripheral surface of the spokes 1 And is formed of a material from which triboelectrification occurs. For example, since the inner circumferential surface of the charging unit 2 is coated with a PDMS (Polydimethylsiloxane) material, charging with (-) electric charge is facilitated.

One end of the charging unit 2 is fixed to the hub side of the bicycle and the other end thereof is freely movable so that dynamic behavior of the cantilever type may occur.

The energy harvesting apparatus 100 for a bicycle according to the present invention having such a constitution has a configuration in which the charging unit 100 is installed in the vicinity of the spool 1 by a vibration transmitted to an automobile wheel or a resistance by air flowing between the spoke 1 and the charging unit 2. [ 4 (a), 4 (b) and 4 (c), which is a typical tilting behavior of the charging unit 2, the charging unit 2 repeatedly tilts with respect to the spokes 1 , It is possible to obtain the energy harvesting by the friction charging between the outer circumferential surface of the spoke 1 and the inner circumferential surface of the charging unit 2.

As a result, according to the present invention, the cantilever type charging unit 2 is connected to the hub of the bicycle to enclose the aluminum spoke 1, and the air resistance due to the body vibration at the time of road running and the rotation of the wheel It is possible to replace or assist the power generation of the existing hub dynamo in the present situation where the utilization of the bicycle is being increased because the contact and separation between the spoke 1 and the charging unit 2 can be generated half- The advantage is expected.

The charging unit 2 includes a charging unit 22 capable of performing free motion so as to enable dynamical behavior in the form of a cantilever and a support unit 21 for supporting the charging unit 22 so as to freely move.

The charging unit 22 has an inner circumferential surface which is arranged to surround the spokes 1 and which is in contact with the outer circumferential surface of the spokes 1 and the supporter 21 has one end connected to one of the hub and the rim And the other end is connected to the charging unit 22. [

The present embodiment having such a configuration is configured such that a portion of the charging portion 22 which is not connected to the supporting portion 21 can be tilted relative to the spoke 1, Thereby enabling contact and separation between the spokes 1.

1) Selection of material of charging unit 2

On the other hand, the elastic modulus E of the charging unit 2 can be determined through a mathematical analysis through the linearization model as shown in FIG.

5 is a reference diagram related to mathematical modeling for selecting a material of the charging unit 2 employed in an embodiment of the present invention.

That is, in order to produce continuous and stable electrical energy using the energy harvesting apparatus according to the present invention, the charging unit 22, which is a cylindrical mass, has an amplitude equal to or greater than a certain magnitude with respect to random vibration and air friction of the bicycle body, .

FIG. 5A is a schematic view of the energy harvesting apparatus of FIG. 2. FIG. The mass m represents the mass of the cylindrical hollow shaft (charging portion 22), and E, A, I, l (lower case letters of L) represent the elastic modulus, cross-sectional area, . At this time, since the shape of the charging portion 22 is determined according to the geometrical shape of the spoke 1 itself, the remaining parameters except for the elastic modulus E of the charging portion 22 are determined as constants.

Therefore, the elastic modulus E of the charging portion 22 should be obtained through an appropriate assumption such as linearization, and a material having a physical property corresponding thereto should be used in the production of the charging unit 2. If the elastic modulus E is too large, the charging section 22 will not be bent even by the vibration or air resistance of the bicycle and will not come into contact with the spokes 1. If the elastic modulus E is too small, The spoke 1 will continue to make contact with the spoke 1 due to the continuous contact with the spoke 1 or the occurrence of sag due to the weight of the charging part 22. [

First, in order to obtain the elastic modulus E, the energy harvesting apparatus model of Fig. 5 (a) was linearized by the spring-mass system of Fig. 5 (b). At this time, the excited force F (t) is equal to the air resistance received by the module on a bicycle traveling at a constant speed (25 km / h).

로 표현 하였다. 다음으로

의 크기를 구하기 위해서 원통형 물체 주위를 흐르는 유체의 항력(Drag force)을 구해야 하며, 그 식은 다음과 같다.The upper half of the bicycle wheel receives the maximum force because the bicycle's running direction is the same as the wheel's rotating direction. In the lower half circle, the bicycle's running direction is opposite to the wheel's rotating direction. Therefore, since the excited force, that is, the air resistance, has a constant periodicity

Respectively. to the next

The drag force of the fluid flowing around the cylindrical object should be obtained.

,

는 공기의 밀도, U는 자전거의 주행속도, A는 원통 질량체의 단면적으로 지름과 길이의 곱으로 나타낼 수 있다. At this time,

,

Is the density of air, U is the running speed of the bicycle, and A is the cross-sectional area of the cylindrical mass and can be expressed as the product of the diameter and the length.

을 구할 수 있고, 바퀴의 회전 진동수

임을 알 수 있다.
As a result

And the rotational frequency of the wheel

.

이고, 여기서 최대 진폭은 원통형 질량체의 내부와 스포크(1)와의 초기 거리인 0.002m가 되어야 Press & release motion이 가능하게 된다. Therefore, the solution of this spring - mass system is

, Where the maximum amplitude is 0.002 m, the initial distance between the inside of the cylindrical mass and the spokes 1, enabling the press & release motion.

이고

가 된다. 이 때

이므로, 최종적인 탄성계수 E의 값은

로 구할 수 있다. 결국, 이를 만족할 수 있는 상기 대전부(22)의 재료는 0.0003~2.76GPa의 넓은 탄성계수 범위를 갖는 합성고무에서 적절한 종류를 선택하는 것이 바람직하다.therefore,

ego

. At this time

, The value of the final elastic modulus E is

. As a result, it is preferable to select a suitable type of material for the charging portion 22 that can satisfy this requirement in a synthetic rubber having a wide elastic modulus range of 0.0003 to 2.76 GPa.

The material selection of the charging unit 2 through mathematical modeling has been described above.

The charging unit 22 may further include a plurality of holes 22a so that outside air may be introduced into the charging unit 22 in addition to the through holes for allowing the spokes 1 to pass therethrough .

This embodiment having such a configuration can induce the turbulent flow inside the charging section 22 to further increase the friction through vibration between the spoke 1 and the charging section 22, It has an advantage that it can be further maximized.

The spokes (1) are preferably configured to function as a single electrode because at least a portion connected to the hub is made of the same material as the hub.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Do.

100: Energy harvesting equipment for bicycles
1: spoke 2: charging unit
21: Support part 22:
22a: hole

Claims (4)

A plurality of spokes arranged in a length between a hub disposed at the center of the bicycle wheel and a rim to which the bicycle tire is engaged and formed of a chargeable material; And
A charging unit arranged to surround at least one of the plurality of spokes and having an inner circumferential surface which is in contact with an outer circumferential surface of at least the spokes so as to be capable of friction charging when the outer circumferential surface of the spokes contacts and separates, And an energy recovery device for recovering energy of the bicycle. The method according to claim 1,
The charging unit includes:
A charging unit arranged to surround the spokes and having an inner circumferential surface contacting the outer circumferential surface of the spokes; And
And a support part having one end connected to one of the hub and the rim and the other end connected to the charging part. 3. The method of claim 2,
Wherein the charging unit further includes a plurality of holes so that outside air can be introduced into the charging unit other than the through holes through which the spokes are installed. The method according to claim 1,
Wherein the spoke is made of the same material as at least a portion of the spoke connected to the hub.

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