Inductive power supply system and coil thereof

Abstract

The invention discloses a coil, which is used for an induction type power supply system and comprises a metal wire and a non-metal spacing wire, and the metal wire and the non-metal spacing wire are jointly wound to form the coil.

Description

Technical Field

[0001] The present invention relates to an inductive power supply system and a coil thereof, and in particular to an inductive power supply system and a coil thereof with good electromagnetic induction efficiency. Background Art

[0002] In an inductive power supply, the power supply end and the power receiving end each include a coil, and the power or control signal is transmitted by induction at a certain induction distance. The induction distance represents the relative distance between the two coils. Generally speaking, the closer the distance between the coils, the higher the efficiency of power transmission; conversely, the farther the distance between the coils, the lower the efficiency of power transmission. The longest effective distance of the coils is the maximum relative distance between the coils under the worst acceptable efficiency in the application; and the shortest effective distance is the minimum distance between the two coils that can transmit power when the inductive power supply is in normal operation. The effective induction distance is directly related to the coil size. Generally, the larger the coil size, the better the efficiency. However, the space available for the coil in the actual product is limited, and the increase in coil size will increase the cost.

[0003] In view of this, it is necessary to propose a new coil design that can produce a high-efficiency and low-cost coil in a limited space. Summary of the invention

[0004] Therefore, the main purpose of the present invention is to provide a coil structure that can be wound with a non-metallic spacer wire to achieve high efficiency and low cost at the same time.

[0005] An embodiment of the present invention discloses a coil for an inductive power supply system. The coil includes a metal conductor and a non-metallic spacer wire. The metal conductor and the non-metallic spacer wire are wound together to form the coil.

[0006] Another embodiment of the present invention discloses an inductive power supply system, which includes a first coil and a second coil. The first coil is used at a power supply end of the inductive power supply system, and the first coil is wound by a first metal wire and a first non-metallic spacer wire. The second coil is used at a power receiving end of the inductive power supply system, and the second coil is wound by a second metal wire and a second non-metallic spacer wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG. 1 is a schematic diagram of a coil according to an embodiment of the present invention.

[0008] Figure 2 FIG. 1 is a schematic diagram of a coil according to an embodiment of the present invention.

[0009] Figure 3 FIG. 1 is a schematic diagram of a coil according to an embodiment of the present invention.

[0010] Figure 4 FIG. 1 is a schematic diagram of a coil according to an embodiment of the present invention.

[0011] Figure 5 FIG. 1 is a schematic diagram of a coil according to an embodiment of the present invention.

[0012] Figure 6 FIG. 1 is a schematic diagram of an inductive power supply system according to an embodiment of the present invention.

[0013] The reference numerals are described as follows:

[0014] 10, 20, 30, 40, 50 coils

[0015] 102, 202, 302, 402, 502, 632, 642 metal wire

[0016] 104, 204, 304, 404, 504, 506, 634, 644 non-metallic spacer wire

[0018] 60 Inductive Power Supply System

[0019] 61 Power supply module

[0020] 62 Power receiving module

[0021] 63 Power supply coil

[0022] 64 Receiving coil DETAILED DESCRIPTION

[0023] The automated production method of the coil is to place the wire into an automatic winding machine for winding and then shape and fix it. The shaping and fixing methods include hot melt forming or chemical forming. Since the hot melt forming method can be quickly formed, it has become the mainstream in the industry. To achieve hot melt forming, hot melt adhesive can be applied to the outer layer of the coil so that it can be heated and bonded after winding is completed. The coil can be further bonded to a magnetic material (such as a magnetic conductor) and a non-metallic shell can be added to form a coil module. Among them, the magnetic material can be used to enhance the resonant performance of the coil and guide the direction of the coil energy transmission. The non-metallic shell can be used to protect the coil structure and prevent damage to the coil caused by external forces.

[0024] In detail, a set of shafts are set on the coil mold of the automatic winding machine. After the wire is introduced into the surface of the shaft and fixed on the shaft, the shaft starts to rotate and stack in circles. The more circles are wound, the larger the size of the coil. When the winding reaches the set number of circles, the shaft stops rotating, and then the machine cuts off the wire and forms and fixes it. After the wires on the coil are bonded to each other, the machine will remove the coil from the mold, and the coil is wound. The standard coil has a circular structure, and there is a cavity formed by the shaft of the mold on the inside of the coil. The size of the cavity represents the inner diameter of the coil, and the outer edge of the outermost wire of the coil is called the outer diameter of the coil. The two ends of the wire of the coil can be connected to the circuit respectively. On the wire, the part that leaves the innermost and outermost circles of the coil and reaches the circuit is called the lead. During the coil induction process, the lead has no induction ability.

[0025] In an inductive power supply system, one coil can be placed at the power supply end and the other coil can be placed at the power receiving end. During the power transmission process, the energy of the power supply end coil is transferred to the power receiving end coil. When the load on the power receiving end increases and draws higher power, the current passing through the wire on the coil will also increase, and when the power is increased, there will be a larger current passing through the wire of the coil. Under the same current conditions, the greater the impedance of the wire, the greater the loss and heat; the longer the length of the wire, the greater the impedance and the worse the efficiency. Generally speaking, thicker wires can be used to make coils to reduce impedance.

[0026] Therefore, the following requirements are often desired in coil design: First, the larger the coil size, the better. However, in reality, the space of the product is limited and cannot accommodate an overly large coil. Moreover, increasing the coil size will inevitably increase the material cost. Second, the larger the coil induction area, the better. In practical applications, coil induction relies on the area formed by the wire to sense and transfer energy. When the inner diameter of the coil is smaller and the outer diameter is larger, a larger induction area can be constructed. However, such a design is often accompanied by an increase in the length of the wire, resulting in increased impedance and reduced efficiency. Third, the lower the coil impedance, the better. The general coil design method is to thicken the wire or shorten the wire length to reduce the impedance. However, if you want to increase the sensing distance and increase the outer diameter size, but want to control the wire length and impedance size, you must increase the inner diameter size to reduce the number of winding turns, resulting in a decrease in the sensing area and a decrease in the transmission efficiency. Furthermore, the wire itself has existing costs and weight. When the wire is thickened, the cost and weight will increase, which has practical limitations.

[0027] As can be seen from the above, the traditional coil design method often cannot take into account the above three requirements. If one of the requirements is to be met, it may cause a decrease in efficiency in other aspects, and some trade-offs must be made. The applicant proposed in the Chinese patent authorization announcement number CN 108735467 B a method of pre-cutting grooves in a non-metallic upper cover and burying wires in the grooves to form a coil. This method can form a spacing between the wires of the coil, so that the number of turns of the coil is reduced and the length is reduced, while satisfying the advantages of increasing the coil induction area and reducing the coil impedance. This method can complete a high-efficiency coil, but the production process is relatively cumbersome and costly, which is not conducive to mass production.

[0028] In order to improve the above-mentioned disadvantage of being difficult to produce, the present invention proposes a coil structure that can be wound by a metal conductor and a non-metallic spacer wire to meet the needs of increasing the coil size and increasing the coil induction area while maintaining a low impedance. In addition, the coil of the present invention can be produced by winding in an automated manner, and its production is fast and low-cost.

[0029] In one embodiment, a coil may be formed by winding a metal conductive wire together with a non-metallic spacer wire. Figure 1 Schematic diagram of a coil 10 according to an embodiment of the present invention. The coil 10 includes a metal wire 102 and a non-metal spacer wire 104, and the coil 10 is formed by winding the metal wire 102 and the non-metal spacer wire 104 in parallel. In order to achieve a larger coil induction area and maintain a lower coil impedance (i.e., a shorter coil length), if the metal wire 102 and the non-metal spacer wire 104 are wound on a plane, the metal wire 102 and the non-metal spacer wire 104 can be bonded along the direction of the plane, so that different line segments of the metal wire 102 are separated by the non-metal spacer wire 104. For example, Figure 1 As shown, the outermost first and second turns of the metal wire 102 are separated by the first turn of the non-metal spacer wire 104. Therefore, the structure of the wound coil 10 is a circle of metal, a circle of non-metal, a circle of metal, a circle of non-metal, etc., which are arranged alternately in sequence.

[0030] Traditionally, the entire coil is wound by metal wire. In order to achieve a sufficient inductive area, a large number of turns are required, which increases the length of the entire wire, thereby causing an increase in impedance and a decrease in efficiency. In contrast, the coil of the present invention is wound by a metal wire and a non-metallic spacer wire in parallel, so each turn of metal wire in the finished coil is separated by a non-metallic spacer wire. Compared to the existing coil with an all-metal winding structure, since there are gaps between the wires on the coil of the present invention, under the same coil size, the number of wire turns required to be wound is halved to still achieve the same inductive area, and the length of the wire is halved to maintain a lower impedance.

[0031] In addition, the coil structure of the present invention can be produced by using a double-wire parallel winding technology on an automatic winding machine, which has the advantage of being suitable for automated production and can significantly reduce costs in mass production. Figure 1 In the embodiment, adhesive can be coated on the surface of the metal wire 102 and the non-metallic spacer wire 104 respectively. When the coil is formed, the adhesive on the wire / spacer wire becomes sticky through temperature change or chemical action, so that the metal wire 102 and the non-metallic spacer wire 104 are bonded and fixed to each other. The finished coil can be easily completed by automatic winding using an automatic winding machine.

[0032] The non-metallic spacer wire 104 can be made of any material that does not have electrical conductivity and electromagnetic induction capabilities. In one embodiment, a plastic wire that is similar in shape and hardness to the metal wire 102 can be used to implement the non-metallic spacer wire 104 so that the two wires can be wound in parallel. The plastic wire does not have electrical conductivity and electromagnetic induction capabilities, and can penetrate electromagnetic energy without consuming energy or interfering with the induction function of the metal coil. In addition, the plastic wire has the advantages of light weight and cheap materials, which can reduce weight when making large-sized coils and reduce costs under mass production. Furthermore, if an elastic plastic wire is used, the spacing between different turns of metal wires can be further flexibly adjusted to achieve different applications.

[0033] It is worth noting that in the coil 10, only the metal wire 102 has electromagnetic induction capability, so in order to achieve a larger outer diameter (equivalent to a larger induction area), the metal wire 102 should preferably be arranged outside the non-metallic spacer wire 104. In other words, the outermost circle on the coil 10 is the metal wire 102.

[0034] In some embodiments, a plastic wire with elastic material can be selected as the non-metallic spacer wire, and different rotational torques are applied during the winding process to cause the plastic wire to deform due to stress and change its width. In this case, different line segments of the non-metallic spacer wire may have different widths. Generally speaking, increasing the torque can reduce the width of the plastic wire to reduce the spacing of the metal wires; reducing the torque can increase the width of the plastic wire to increase the spacing of the metal wires.

[0035] For example, Figure 2 Schematic diagram of a coil 20 according to an embodiment of the present invention. The coil 20 is wound by a metal wire 202 and a non-metallic spacer wire 204, wherein the non-metallic spacer wire 204 is made of an elastic material and can be wound with different torques to form coils of different widths. In this example, the line segments on the inner circle of the non-metallic spacer wire 204 have a larger width, and the torque is gradually increased from the inside to the outside during the winding process, so that the line segments on the outer circle have a smaller width.

[0036] Note Figure 2 The coil structure is only one of many embodiments of the present invention. In other embodiments, other methods can also be used to change the torque. For example, Figure 3 The coil 30 is wound by a metal conductor 302 and a non-metallic spacer wire 304. During the manufacturing process, a larger torque is first used and then gradually reduced, so that the width of the non-metallic spacer wire 304 is smaller in the inner circle and gradually increases from the inside to the outside.

[0037] Figure 4 Another coil structure is shown, in which the coil 40 is wound by a metal wire 402 and a non-metallic spacer wire 404. In the process of making the coil 40, a larger torque may be used first, then gradually reduced and then increased, so that the non-metallic spacer wire 404 presents a state in which the inner and outer circles have smaller widths and the middle width is larger. In this way, the spacing of the metal wire 402 on the inner and outer sides of the coil 40 is smaller and the spacing in the middle is larger.

[0038] Generally speaking, the energy distribution on the coil is that the energy at the ends of the wire is the strongest and the energy in the middle is the weakest. If a non-metallic spacer wire with a constant width is used for winding, the density of the metal wires at the ends and the middle of the coil must be the same. In contrast, by using a non-metallic spacer wire with a variable width, in addition to generating a smaller impedance under the same coil area, the width of the non-metallic spacer wire can be increased in the middle of the coil, so that the density of the metal wires in the middle of the coil is lower than that of the metal wires at the ends of the coil, such as Figure 4 This reduces the length of the wire in the middle section where the energy is weaker, thereby reducing impedance and improving power transmission efficiency.

[0039] It is worth noting that the purpose of the present invention is to propose a coil structure that can meet various requirements of coil design, improve coil efficiency, and facilitate mass production. Those skilled in the art can make modifications or changes accordingly, but are not limited to this. For example, in the above embodiment, the coil is wound by a metal wire and a non-metallic spacer wire. In another embodiment, multiple non-metallic spacer wires can also be used to wind a metal wire together to further reduce the density and impedance of the metal wire.

[0040] For example, Figure 5 Schematic diagram of a coil 50 according to an embodiment of the present invention. The coil 50 is wound by a metal wire 502 and non-metallic spacer wires 504 and 506. The three wires are bonded on the same plane, so that two adjacent turns of the metal wire 502 are separated by two non-metallic spacer wires 504 and 506. In another embodiment, more than three non-metallic spacer wires may be provided in the coil, and the number of non-metallic spacer wires shall not be used to limit the scope of the present invention.

[0041] In an inductive power supply system, the power supply coil and the receiving coil need to be inductively coupled at a certain distance to achieve good power transmission efficiency. Generally speaking, the farther the distance between the coils, the worse the power transmission efficiency. If the distance between the two coils is too far, the efficiency required by the product specifications may not be achieved; if the distance between the two coils is too close, over-induction may occur. Over-induction (also known as over-coupling) means that when the distance between the two coils is very short, the wires on the coils may completely overlap and be close to each other. At this time, the energy from the power supply end will be completely transmitted to the receiving end, and the coil at the receiving end will receive an extremely high voltage and transmit it to the back-end circuit, but the voltage that the back-end circuit can withstand is limited, so in the case of over-induction, the receiving end circuit is easily damaged.

[0042] In an embodiment of the present invention, the metal conductor and the non-metallic spacer wire are wound in parallel to form a coil, and the over-induction condition can be avoided or alleviated by adjusting the elasticity of the non-metallic spacer wire. Figure 6 Schematic diagram of an inductive power supply system 60 according to an embodiment of the present invention. The inductive power supply system 60 includes a power supply module 61 and a power receiving module 62. A power supply coil 63 is provided in the power supply module 61, which is wound by a metal wire 632 and a non-metallic spacer wire 634. A power receiving coil 64 is provided in the power receiving module 62, which is wound by a metal wire 642 and a non-metallic spacer wire 644. Similarly, the non-metallic spacer wires 634 and 644 can be made of plastic wires or other materials that do not have electrical conductivity and electromagnetic induction capabilities.

[0043] During the operation of the inductive power supply system 60, in order to avoid excessive induction between the power supply coil 63 and the power receiving coil 64, it is necessary to avoid the metal wires 632 and 642 from overlapping each other when the two coils are close to each other. In this case, the non-metallic spacer wire 634 and the non-metallic spacer wire 644 can be designed to have different widths. In this way, even when the power supply coil 63 and the power receiving coil 64 are close to each other, the positions of the metal wires 632 and 642 are still staggered and do not overlap each other.

[0044] In this example, the width of the non-metallic spacer wire 634 is smaller and the width of the non-metallic spacer wire 644 is larger. Therefore, in the wound power supply coil 63 and the power receiving coil 64, even if the two coils are close to each other, the position of the metal wire 632 and the position of the metal wire 642 are still staggered from each other, which can avoid the occurrence of excessive induction. Similarly, non-metallic spacer wires with different widths can also be realized by using elastic plastic wires and adjusting the torque during the coil winding process.

[0045] In other embodiments, the positions of the metal wires may be staggered in other ways. For example, a non-metallic spacer wire with a larger width may be used in the power supply end coil and a non-metallic spacer wire with a smaller width may be used in the power receiving end coil, which can also achieve the purpose of staggering the metal wires. In another embodiment, the power supply coil may be designed to have a Figure 2 The structure of the non-metallic spacer wire is wider inside the coil and narrower outside the coil; at the same time, the receiving coil is designed to have Figure 3 The structure of the non-metallic spacer wire is narrower on the inner side of the coil and wider on the outer side of the coil. In this way, the position of the metal wire can be staggered to avoid excessive induction of the coil and damage to the receiving end circuit.

[0046] In summary, the present invention proposes a coil structure that can be wound together with a non-metallic spacer wire (such as a plastic wire) and a metal wire. In one embodiment, an elastic plastic wire can be used as a non-metallic spacer wire to flexibly adjust the spacing between different turns of metal wires. At the same time, the positions of the metal wires can be staggered through appropriate designs of the power supply coil and the power receiving coil to avoid excessive induction of the coil and damage to the back-end circuit. The coil structure of the present invention can use shorter wires to achieve a larger induction area, thereby providing optimized electromagnetic induction capabilities while maintaining lower coil impedance. In addition, the coil can be produced on an automatic winding machine using a double-wire parallel winding technology, which can be automated and mass-produced, and has the advantage of low cost.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A coil for an inductive power supply system, characterized in that: The coil includes: a metal wire; and - non-metallic spacer wire; The metal conductor and the non-metallic spacer wire are wound together to form the coil.

2. The coil according to claim 1, characterized in that The non-metallic spacer wire is a plastic wire.

3. The coil according to claim 1, characterized in that The metal conductor and the non-metallic spacer wire are wound on a plane and bonded along the direction of the plane.

4. The coil according to claim 1, characterized in that A first line segment and a second line segment of the metal conductive line are separated by the non-metallic spacing line and have a distance therebetween.

5. The coil according to claim 1, characterized in that A first line segment and a second line segment of the non-metallic spacing line have different widths.

6. The coil according to claim 1, characterized in that The outermost circle on the coil is the metal wire.

7. The coil according to claim 1, characterized in that The coil also includes: A plurality of non-metallic spacer wires are used to be wound together with the metal conductor to form the coil.

8. An inductive power supply system, characterized in that: include: a first coil, used for a power supply end of the inductive power supply system, the first coil being wound by a first metal wire and a first non-metal spacer wire; and A second coil is used for a power receiving end of the inductive power supply system. The second coil is formed by winding a second metal wire and a second non-metallic spacer wire together.

9. The inductive power supply system as claimed in claim 8, wherein: The first non-metallic spacer wire and the second non-metallic spacer wire are plastic wires.

10. The inductive power supply system as claimed in claim 8, wherein: The first non-metallic spacing line and the second non-metallic spacing line have different widths.

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