E-type small ripple low-noise transformer and manufacturing process

Abstract

The present invention discloses an E-type small ripple low-noise transformer and a manufacturing process. The transformer includes a transformer skeleton and a magnetic core mounted on the transformer skeleton. The magnetic core is composed of two butt-jointed E-type magnetic cores. The E-type magnetic core includes a bottom, side columns vertically connected to the left and right sides of the bottom, and a middle column vertically connected to the middle of the bottom. There is an air gap between the butt-jointed ends of the middle columns of the two E-type magnetic cores. The butt-jointed end faces of the middle columns of the two E-type magnetic cores are coated with polyester polyhydroxy resin. The polyester polyhydroxy resin is coated by an automatic dispensing machine, and after dispensing, it is baked in an oven. The present invention solves the problem that in low-latitude countries, in a low-temperature environment, the ripples and noise of traditional transformers are relatively large due to the low-temperature frequency characteristics of materials and the process.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformers, and particularly relates to an E-type small ripple low-noise transformer. Background Art

[0002] Since customers in Denmark, Sweden and other places are close to the Arctic Circle and the temperature is relatively low, electronic products are required to meet the ripple and noise requirements in a low-temperature use environment.

[0003] At present, the ripple value range of conventional E-type transformers in a low-temperature environment is between 315 and 438, and the noise value range is 30 - 40 dB, which is difficult to meet the use requirements of customers for small ripple and low noise. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an E-type small ripple low-noise transformer, which can also have a small ripple value and low noise in a low-temperature environment, and avoid the failure of transformer products during operation at low temperature.

[0005] To solve the above technical problem, the present invention adopts the following technical solution: an E-type small ripple low-noise transformer, including a transformer skeleton, a coil winding wound on the transformer skeleton, and a magnetic core installed on the transformer skeleton. The coil winding includes a primary winding and a secondary winding. The transformer skeleton is provided with primary pins on the primary side and secondary pins on the secondary side. The lead-out wire of the primary winding is connected to the primary pins, and the lead-out wire of the secondary winding is connected to the secondary pins. The magnetic core is composed of two E-type magnetic cores butt-jointed. The E-type magnetic core includes a bottom, side columns vertically connected to the left and right sides of the bottom, and a middle column vertically connected to the middle of the bottom. There is an air gap between the butt-jointed ends of the middle columns of the two E-type magnetic cores. There is an air gap between the butt-jointed ends of the middle columns of the two E-type magnetic cores, and the butt-jointed end faces of the middle columns of the two E-type magnetic cores are coated with polyester polyhydroxy resin.

[0006] Preferably, the air gap between the butt-jointed ends of the middle columns of the two E-type magnetic cores is 0.22 mm, and the thickness of the polyester polyhydroxy resin is 0.21 mm.

[0007] Preferably, the primary pins are composed of PIN1, PIN2, PIN3, PIN4, and PIN5, and the secondary pins are composed of PIN6, PIN7, PIN8, PIN9, and PIN10. After soldering, 2 / 3 of PIN4 is cut off.

[0008] Preferably, a first shielding copper foil is wrapped around the outer circumference of the magnetic core, and a second shielding copper foil is wrapped around the outer circumference of the coil winding. The second shielding copper foil and the first shielding copper foil are cross-shaped and the second shielding copper foil is located outside the first shielding copper foil.

[0009] Preferably, the cross - intersection joint of the second shielding copper foil and the first shielding copper foil and the lead wire tail of the PIN3 pin are welded together.

[0010] Preferably, a first tape is circumferentially coated on the outer side of the coil winding, and a second tape is circumferentially coated on the outer side of the magnetic core. The second tape intersects the first tape at a cross - angle and is located outside the first tape. The first tape and the second tape are located outside the first shielding copper foil and the second shielding copper foil.

[0011] The present invention also provides a manufacturing process for an E - type small - ripple low - noise transformer, which includes the following steps:

[0012] Step S1: Before assembling the magnetic core, polyester polyhydroxy resin is coated on the butting end faces of the middle columns of the two E - type magnetic cores. After assembling the magnetic core, a fixing tape is circumferentially coated and fixed on the outer side of the magnetic core, and the polyester polyhydroxy resin is dried.

[0013] Step S2: The transformer is vacuum - impregnated with insulating paint and then dried.

[0014] Step S3: A first shielding copper foil is circumferentially coated on the outer side of the magnetic core, and then a second shielding copper foil is circumferentially coated on the outer side of the coil winding.

[0015] Step S4: The cross - intersection joint of the second shielding copper foil and the first shielding copper foil and the lead wire tail of the PIN3 pin are welded together.

[0016] Step S5: A first tape is circumferentially coated on the outer side of the coil winding, and then a second tape is circumferentially coated on the outer side of the magnetic core.

[0017] Preferably, an automatic dispensing machine is used to coat the polyester polyhydroxy resin. After dispensing, it is baked in an oven. The baking temperature is 120 degrees Celsius, and the baking time is 1 to 2 hours until the polyester polyhydroxy resin is dried.

[0018] Preferably, in step S2, the specific gravity of the insulating paint and the diluent is 0.895 ± 0.01, and the ratio is tested every 4 hours. If the specific gravity is found to be greater than 0.905 during the test, an appropriate amount of diluent is added. If it is less than 0.885, an appropriate amount of insulating paint is added.

[0019] Preferably, the flying wire exits from the slot opening provided at the top of the secondary side of the transformer skeleton. The flying wire includes flying wire A and flying wire B. Among them, flying wire A is sleeved with a transparent sleeve, flying wire B is sleeved with a black sleeve. The total length of the flying wire is 35 mm, the tinned length is 5 mm, and the flying wire sleeve extends into the coil winding by at least 3 / 4 of its length.

[0020] After analyzing the influence of the thermal expansion coefficients of the transformer skeleton, magnetic core, copper wire, and tape on the electrical parameters in a low - temperature environment, the technical solution adopted by the present invention uses an automatic gluing process to control the dosage of the polyester polyhydroxy resin through an automatic dispensing machine to fill the air gap in the middle column of the magnetic core, improving the ripple and noise problems.

[0021] Coating the middle post of the magnetic core with polyester polyhydroxy resin can improve the ripple and noise. Reason analysis:

[0022] At high frequencies, ripple and noise basically exist in the circuit simultaneously. When the coil vibrates at high frequencies, there will inevitably be the telescopic vibration of the coil and the telescopic vibration of the magnetic core. Since there is an air gap between the magnetic core and the coil, the combination is not tight, resulting in a large telescopic vibration space and generating a hissing sound. This sound is generated by the vibration of the materials, which is the noise we mentioned. Inevitably, there will be some AC components in the DC steady quantity to some extent. This AC component superimposed on the DC steady quantity is called ripple. In the old products, due to the large difference in the thermal expansion coefficients between relevant materials and the loose joint at low temperatures, the noise and ripple are relatively large.

[0023] The thermal expansion coefficient of the coated polyester polyhydroxy resin is closest to that of the magnetic core coil in a low-temperature environment. After filling the polyester polyhydroxy resin in the middle post of the magnetic core, due to the closer joint between the magnetic core and the skeleton coil, the telescopic vibration space becomes smaller. And the polyester polyhydroxy resin also has a sound insulation effect similar to that of sound insulation cotton. For the transformer product, because the telescopic vibration space is limited, the noise disappears, and the product is more popular in the market.

[0024] Therefore, the present invention has the following beneficial effects: It solves the problem that in low-latitude countries, traditional transformers have relatively large ripple and noise under low-temperature environments due to the low-temperature frequency characteristics of materials and the process. The new technical solution has stable performance, reliable quality, a relatively wide operating temperature range, and can meet the environmental requirements of low-latitude countries such as those in Northern Europe and North America.

[0025] Due to its high performance, low cost and other characteristics, it can be widely applied to smart meters, solar energy, charging piles, industrial power supplies, new energy fields, etc.

[0026] The specific technical solution and its beneficial effects of the present invention will be described in detail in the following specific embodiments in conjunction with the drawings. Brief Description of the Drawings

[0027] The present invention will be further described below in conjunction with the drawings and specific embodiments:

[0028] Figure 1 It is a schematic structural diagram of the E-type small-ripple and low-noise transformer of the present invention;

[0029] Figure 2 It is a schematic structural diagram of the pin part;

[0030] In the figure: 1 - transformer skeleton, 2 - coil winding, 3 - magnetic core, 4 - polyester polyhydroxy resin. Specific Embodiments

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0032] Those skilled in the art can understand that, without conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0033] Embodiment 1

[0034] Refer to Figure 1 and Figure 2 As shown, the E-type small ripple low-noise transformer includes a transformer skeleton 1, a coil winding 2 wound on the transformer skeleton, and a magnetic core 3 installed on the transformer skeleton. The coil winding includes a primary winding and a secondary winding. The transformer skeleton is provided with primary pins on the primary side and secondary pins on the secondary side. The lead-out wire of the primary winding is connected to the primary pins, and the lead-out wire of the secondary winding is connected to the secondary pins. The magnetic core is composed of two E-type magnetic cores butt-jointed. The E-type magnetic core includes a bottom, side columns vertically connected to the left and right sides of the bottom, and a middle column vertically connected to the middle of the bottom. There is an air gap between the butt-jointed ends of the middle columns of the two E-type magnetic cores, and there is no air gap between the butt-jointed ends of the side columns of the two E-type magnetic cores. A polyester polyhydroxy resin 4 is coated on the butt-jointed end faces of the middle columns of the two E-type magnetic cores. Or polyester polyhydroxyl resin is coated on the butt-jointed end faces of the side columns of the two E-type magnetic cores at the same time. The above-mentioned polyester polyhydroxy resin can use the products of German company WEVO. Usually, when there is a cross copper foil outside the transformer, only the butt-jointed end faces of the middle columns need to be coated with polyester polyhydroxy resin. If there is no cross copper foil outside the transformer, the butt-jointed end faces of the side columns need to be coated with polyester polyhydroxy resin at the same time, so as to reduce the telescopic movement between the transformer materials to achieve the effect of reducing ripple and removing low noise.

[0035] Analysis of the reasons why coating the middle column of the magnetic core with polyester polyhydroxy resin can improve ripple and noise:

[0036] At high frequencies, ripple and noise basically exist in the circuit simultaneously. When the coil vibrates at a high frequency, there will inevitably be the telescopic vibration of the coil and the telescopic vibration of the magnetic core. Since there is an air gap between the magnetic core and the coil, the combination is not tight, resulting in a large telescopic vibration space and generating a hissing sound. This sound is generated by the vibration of the materials, which is the noise we mentioned. Inevitably, there will be some AC components in the DC steady quantity to some extent. This AC component superimposed on the DC steady quantity is called ripple. In the old products, due to the large difference in the thermal expansion coefficients between relevant materials and the loose joint in the low-temperature environment, the noise and ripple are relatively large.

[0037] The thermal expansion coefficient of the polyester polyhydroxy resin in the low-temperature environment is closest to that of the magnetic core coil. After filling the polyester polyhydroxy resin in the middle column of the magnetic core, since the magnetic core and the skeleton coil are joined more tightly, the telescopic vibration space becomes smaller. And the polyester polyhydroxy resin also has the sound insulation effect similar to that of the sound insulation cotton. For the product transformer, because the telescopic vibration space is limited, the noise disappears, and the product is more popular in the market.

[0038] Among them, the air gap between the docking ends of the middle columns of the two E-shaped magnetic cores is about 0.22 mm, and the thickness of the polyester polyhydroxy resin is about 0.21 mm. Usually, the thickness of the polyester polyhydroxy resin = the air gap thickness - 0.1 mm is sufficient. Here, a certain margin is designed mainly considering the difference in thermal expansion coefficients.

[0039] The primary pins are composed of PIN1, PIN2, PIN3, PIN4, and PIN5, and the secondary pins are composed of PIN6, PIN7, PIN8, PIN9, and PIN10. After soldering, 2 / 3 of PIN4 is cut off.

[0040] A first shielding copper foil is wrapped around the outer circumference of the magnetic core, and a second shielding copper foil is wrapped around the outer circumference of the coil winding. The second shielding copper foil and the first shielding copper foil are cross-shaped and the second shielding copper foil is located outside the first shielding copper foil. The second shielding copper foil and the first shielding copper foil form a cross-shaped shielding copper foil F, and the cross-junction and the lead wire tail of PIN3 are welded together. There are two purposes for setting the cross-shaped shielding copper foil (equivalent to a shielding cover surrounding the transformer product). First, it shields the external electric field to prevent electromagnetic interference (EMI); second, it fixes the wire package and the magnetic core to reduce the noise and ripple generated by the product due to high-frequency vibration.

[0041] A first tape is wrapped around the outer circumference of the coil winding, and a second tape is wrapped around the outer circumference of the magnetic core. The second tape and the first tape are cross-shaped and the second tape is located outside the first tape. The first tape and the second tape are located outside the first shielding copper foil and the second shielding copper foil. Wrapping the tape can improve the HP (insulation withstand voltage test) and avoid the short-circuit problem caused by too small creepage distance between windings.

[0042] Embodiment 2

[0043] Manufacturing process of E-type small ripple low-noise transformer, including the following steps:

[0044] Step S1, before assembling the magnetic core, apply polyester polyhydroxy resin on the butting end faces of the middle columns of two E-type magnetic cores, or apply polyester polyhydroxy resin on the butting end faces of the middle columns of two E-type magnetic cores simultaneously. After assembling the magnetic core, wrap and fix the tape along the outer circumference of the magnetic core, and dry the polyester polyhydroxy resin;

[0045] Step S2, vacuum impregnate the transformer pins with insulating paint and dry them;

[0046] Step S3, wrap the first shielding copper foil along the outer circumference of the magnetic core, and then wrap the second shielding copper foil along the outer circumference of the coil winding;

[0047] Step S4, weld the cross intersection of the second shielding copper foil and the first shielding copper foil and the lead wire tail of PIN3 together;

[0048] Step S5, wrap the first tape along the outer circumference of the coil winding, and then wrap the second tape along the outer circumference of the magnetic core.

[0049] In this embodiment, an automatic dispensing machine is used to apply polyester polyhydroxy resin. After application, it is put into an oven for baking. The baking temperature is 120 °C, and the baking time is 1 to 2 hours until the polyester polyhydroxy resin is dried.

[0050] Among them, in step S2, the specific gravity of the insulating paint and the thinner is 0.895 ± 0.01, and the ratio is tested once every 4 hours. If it is found that the specific gravity is greater than 0.905 during the test, an appropriate amount of thinner is added. If it is less than 0.885, an appropriate amount of insulating paint is added.

[0051] The flying wires fly out from the card slot opening provided at the top of the secondary side of the transformer skeleton. The flying wires include flying wire A and flying wire B. Among them, flying wire A is sleeved with a transparent sleeve and is close to PIN10, flying wire B is sleeved with a black sleeve and is close to PIN6. The total length of the flying wires is 35 mm, the tinned length is 5 mm, and the flying wire sleeve extends into the coil winding by at least 3 / 4 of the length.

[0052] Compare the transformer without applying polyester polyhydroxy resin originally with the E-type small ripple low-noise transformer of the present invention. Among them, the relevant parameters of the original transformer are:

[0053] 1. Ripple value range: between 315 - 438;

[0054] 2. Noise value range: 30 - 40 dB;

[0055] 3. Operating temperature range: between -10 °C and 125 °C;

[0056] 4. Q value: 42;

[0057] 5. Output power: 7.7W

[0058] 6. Superimposed current: 0.88A @ 25°C;

[0059] 7. Withstand voltage test HP TESTING: 3200VAC / 5Ma / 2S / 50Hz

[0060] The relevant parameters of the E-type small ripple and low noise transformer of the present invention are as follows:

[0061] 1. Ripple value range: 180mV Max.

[0062] 2. Noise value range: 25dB Max;

[0063] 3. Operating temperature range: -20°C - 125°C;

[0064] 4. Q value: 25 MIN;

[0065] 5. Output power: 8W;

[0066] 6. Superimposed current: 0.8A Min @ 25°C;

[0067] 7. Withstand voltage test HP TESTING: 3000VAC / 5Ma / 2S / 50Hz.

[0068] For the low-temperature test, all electrical test indicators have good consistency in the special environment of Northern Europe, with small ripple and low noise, and can meet the usage requirements in the low-temperature environment. Due to its high performance, low cost and other characteristics, it can be widely applied to smart meters, solar energy, charging piles, industrial power supplies, new energy fields, etc.

[0069] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. E-type small ripple and low-noise transformer, comprising a transformer skeleton, a coil winding wound on the transformer skeleton, and a magnetic core mounted on the transformer skeleton. The coil winding includes a primary winding and a secondary winding. The transformer skeleton is provided with primary pins on the primary side and secondary pins on the secondary side. The lead-out wire of the primary winding is connected to the primary pins, and the lead-out wire of the secondary winding is connected to the secondary pins. The primary pins are composed of PIN1, PIN2, PIN3, PIN4, and PIN5. The magnetic core is composed of two E-type magnetic cores butt-jointed. The E-type magnetic core includes a bottom, side posts vertically connected to the left and right sides of the bottom, and a middle post vertically connected to the middle of the bottom. There is an air gap between the butt-jointed ends of the middle posts of the two E-type magnetic cores. It is characterized in that: The butt-jointed end faces of the middle posts of the two E-type magnetic cores are coated with polyester polyhydroxy resin; The manufacturing process of the above E-type small ripple and low-noise transformer includes the following steps: Step S1, before assembling the magnetic core, the butt-jointed end faces of the middle posts of the two E-type magnetic cores are coated with polyester polyhydroxy resin. After assembling the magnetic core, a fixing tape is wrapped around the outer circumference of the magnetic core, and the polyester polyhydroxy resin is dried; Step S2, the transformer is vacuum-impregnated with insulating paint and dried; Step S3, a first shielding copper foil is wrapped around the outer circumference of the magnetic core, and then a second shielding copper foil is wrapped around the outer circumference of the coil winding; Step S4, the cross connection of the second shielding copper foil and the first shielding copper foil at the cross intersection and the lead wire tail of PIN3 are welded together; Step S5, a first tape is wrapped around the outer circumference of the coil winding, and then a second tape is wrapped around the outer circumference of the magnetic core; The polyester polyhydroxy resin is coated by an automatic dispensing machine. After dispensing, it is put into an oven for baking. The baking temperature is 120 degrees Celsius, and the baking time is 1 hour to 1.5 hours until the polyester polyhydroxy resin is dried.

2. The E-type small ripple and low-noise transformer according to claim 1, It is characterized in that: The air gap between the butt-jointed ends of the middle posts of the two E-type magnetic cores is 0.22 mm, and the thickness of the polyester polyhydroxy resin is 0.21 mm.

3. The E-type small ripple and low-noise transformer according to claim 1, It is characterized in that: The secondary pins are composed of PIN6, PIN7, PIN8, PIN9, and PIN10. 2 / 3 of PIN4 is cut off after soldering.

4. The E-type small ripple and low-noise transformer according to claim 1, It is characterized in that: A first tape is wrapped around the outer circumference of the coil winding, and a second tape is wrapped around the outer circumference of the magnetic core. The second tape and the first tape are cross-connected and located outside the first tape. The first tape and the second tape are located outside the first shielding copper foil and the second shielding copper foil.

5. The E-type small ripple and low-noise transformer according to claim 1, It is characterized in that: In step S2, the specific gravity of the insulating paint and the thinner is 0.895 ± 0.01, and the ratio is tested once every 4 hours. If it is found that the specific gravity is greater than 0.905 during the test, an appropriate amount of thinner is added. If it is less than 0.885, an appropriate amount of insulating paint is added.

6. The E-type small ripple and low-noise transformer according to claim 1, It is characterized in that: The flying wires extend out from the slot openings at the top of the secondary side of the transformer skeleton. The flying wires include flying wire A and flying wire B. Among them, flying wire A is sleeved with a transparent sleeve, and flying wire B is sleeved with a black sleeve. The total length of the flying wires is 35 mm, the tinned length is 5 mm, and the sleeves of the flying wires extend into the coil winding by at least 3 / 4 of the length.

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