Hermetic terminal and compressor

Abstract

An airtight terminal according to the present disclosure comprises: a conducting pin; a cylindrical insulating member which is open at a high-pressure side and a low-pressure side and is formed to be provided with a through-hole for inserting the conducting pin; an annular member composed of a metal surrounding the insulating member; and a brazing part for fixing the conducting pin to a main surface of the insulating member at the high-pressure side, or to a protrusion surface of a protrusion section provided to the main surface. The insulating member comprises: a base section positioned in an internal space of the annular member; and an extension section extending from the base section toward the low-pressure side. The outermost diameter of the base section is greater than the outermost diameter of the extension section. A compressor according to the present disclosure comprises: a casing which accommodates a motor for compressing a coolant; and the airtight terminal attached to the casing.

Description

Technical Field

[0001] The present disclosure relates to an airtight terminal and a compressor.

Background Art

[0002] An airtight terminal used in a refrigerant compressor (compressor) such as a refrigerator or an air conditioner is required to have high pressure resistance and high voltage resistance because the compressor is disposed in a pressure-resistant container filled with a refrigerant.

[0003] For example, in Patent Document 1, a metal outer ring including a circular top plate portion, a cylindrical portion extending downward from the outer peripheral end of the top plate portion, a flange portion extending from the lower end of the cylindrical portion, and a small cylindrical portion extending inward from the top plate portion and having a lead sealing hole formed therein, a lead sealed to the lead sealing hole of the metal outer ring via a sealing glass, and an insulating sleeve welded to the sealing glass on the inner surface side of the metal outer ring are provided. An airtight terminal for a compressor in which the insulating sleeve is welded so as to extend parallel to the top plate portion and beyond the small cylindrical portion on the inner surface side of the metal outer ring has been proposed. Further, it is described that the insulating sleeve is made of ceramics such as alumina and forsterite.

[0004] In Patent Document 2, a columnar insulator having a through hole formed in the axial direction, a conductor pin inserted with both ends protruding into the through hole, a metal joining member for hermetically joining the end face of the insulator and the conductor pin, and a metal sleeve joined to the outer peripheral surface of the insulator are provided. At least one of the metal joining members includes a cylindrical main body portion having a smaller diameter than the insulator and a larger diameter than the conductor pin, a flange portion integrally provided on one end side of the main body portion and joined to the end face of the insulator, and a cylindrical portion integrally provided on the other end side of the main body portion via a stepped portion and through which the conductor pin is inserted and joined. An airtight terminal has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The hermetic terminal according to the present disclosure includes a conductive pin, a columnar insulating member having through holes that open to the high-pressure side and the low-pressure side for inserting the conductive pin, an annular member made of metal surrounding the insulating member, and a brazing portion that fixes the conductive pin to the main surface of the high-pressure side of the insulating member or the convex surface of the convex portion provided on the main surface. The insulating member includes a base portion located in the internal space of the annular member and an extending portion extending from the base portion toward the low-pressure side. The outermost diameter of the base portion is larger than the outermost diameter of the extending portion.

[0007] The compressor according to the present disclosure includes a casing that houses a motor for compressing a refrigerant, and the above-described hermetic terminal attached to the casing. Electric power from an external power source is supplied to the motor via the conductive pin. [Brief Description of the Drawings]

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0009] When the volume of the insulating sleeve (Patent Document 1) inside the inner space of the metal outer ring is large, there is a problem that higher withstand voltage is required. Also, in the fixation by the metal sleeve (Patent Document 2), there is a problem that the insulator is likely to peel off from the metal sleeve due to the shearing action. Further, when exposed to high temperatures, the sealing glass is likely to melt, and it is required to have a structure that can withstand high temperatures.

[0010] The present disclosure provides an airtight terminal and a compressor having high withstand voltage and pressure resistance.

[0011] The airtight terminal and the compressor according to the present disclosure have high withstand voltage and pressure resistance.

[0012] <Airtight terminal> Hereinafter, the airtight terminal of the non-limiting embodiment of the present disclosure will be described in detail with reference to the drawings. However, in each of the drawings referred to below, for convenience of explanation, only the main members necessary for explaining the embodiment are shown in a simplified manner. Therefore, the airtight terminal may include any constituent member not shown in each of the drawings referred to. Also, the dimensions of the members in each drawing do not faithfully represent the dimensions of the actual constituent members and the dimensional ratios of the respective members.

[0013] The airtight terminal 1 includes a conductive pin 2, an insulating member 3, an annular member 4, and a brazing portion 5 as shown in an example in FIGS. 1 to 5. This airtight terminal 1 can be used, for example, in a compressor or the like. Hereinafter, taking the case where the airtight terminal 1 is for a compressor as an example, each component of the airtight terminal 1 will be described in order.

[0014] The conduction pin 2 has conductivity and can function as a conduction path for inputting and outputting electrical signals between the inside and outside of the pressure-resistant container to which the hermetic terminal 1 is attached. Examples of the material of the conduction pin 2 include metals with good conductivity such as copper (e.g., oxygen-free copper, tough pitch copper, phosphor-deoxidized copper), titanium, nickel, austenitic stainless steel (e.g., SUS304), Cu-Ni alloy (e.g., cupronickel), Fe-Co alloy, Fe-Co-C alloy, Fe-Ni alloy, and Fe-Ni-Co alloy. The shape of the conduction pin 2 may be cylindrical or polygonal. The conduction pin 2 may be one or a plurality. When there are a plurality of conduction pins 2, the number of conduction pins 2 may be 2 or more and 50 or less.

[0015] The insulating member 3 has insulating properties and can hold the conduction pin 2 while electrically insulating it. Examples of the material of the insulating member 3 include electrical insulating materials such as aluminum oxide sintered bodies.

[0016] The shape of the insulating member 3 is cylindrical. More specifically, the shape of the insulating member 3 is cylindrical and extends along the axis S. The axis S passes through the centers of the two main surfaces 32 and 33 of the insulating member 3.

[0017] The insulating member 3 is provided with a through hole 31 for inserting the conduction pin 2. The through hole 31 opens to the high-pressure side A1 and the low-pressure side A2 in the insulating member 3. The high-pressure side A1 may mean the side with relatively higher pressure, and the low-pressure side A2 may mean the side with relatively lower pressure. When using the hermetic terminal 1, the high-pressure side A1 in the insulating member 3 may be located at a place with higher pressure than the low-pressure side A2 in the insulating member 3. For example, when the hermetic terminal 1 is attached to the pressure-resistant container, the main surface 32 of the high-pressure side A1 may be located inside the pressure-resistant container, and the main surface 33 of the low-pressure side A2 may be located outside the pressure-resistant container. The through hole 31 may open to the main surface 32 of the high-pressure side A1 of the insulating member 3 or the convex surface 341 (top surface) of the convex portion 34 provided on the main surface 32, or may open to the main surface 33 of the low-pressure side A2 in the insulating member 3.

[0018] The through-hole 31 may be one or a plurality. The number of the through-holes 31 may be the same as the number of the conduction pins 2. When there are a plurality of through-holes 31, the plurality of through-holes 31 may be positioned at equal intervals along the circumferential direction of the insulating member 3. For example, when there are three through-holes 31, the three through-holes 31 may be positioned so as to be rotationally symmetric at 120° with respect to the axis S of the insulating member 3.

[0019] The conduction pins 2 are inserted into the through-holes 31 in a state where both ends thereof protrude. When a device located inside the pressure-resistant container and a device located outside the pressure-resistant container are electrically connected to both ends of the conduction pins 2 protruding from the through-holes 31, respectively, the airtight terminal 1 can function as a terminal for transmitting an electrical signal between the devices inside and outside the pressure-resistant container.

[0020] The annular member 4 can function as an attachment site for attaching the airtight terminal 1 to the pressure-resistant container. Therefore, the airtight terminal 1 may be attached to the pressure-resistant container via the annular member 4.

[0021] The annular member 4 surrounds the insulating member 3. More specifically, the annular member 4 surrounds at least a part of the insulating member 3. The term "annular" in the annular member 4 is not limited to only an annular shape, but is a concept including an annular or cylindrical shape as long as it can surround the insulating member 3. Therefore, the shape of the annular member 4 is not limited to only an annular shape, and may be annular or cylindrical. For example, as shown in an example in FIG. 3, the shape of the annular member 4 may be cylindrical. Also, the outer diameter of the annular member 4 may be constant.

[0022] The annular member 4 is made of metal. Examples of the metal may include carbon steel for mechanical structures such as S25C, hot-rolled steel for general structures such as SS400 (cold-rolled steel), Fe-Ni-Co alloys, and the like.

[0023] The brazing portion 5 is a part for fixing the conduction pin 2 to the main surface 32 on the high-voltage side A1 of the insulating member 3 or the convex surface 341 of the convex portion 34 provided on the main surface 32. Examples of the brazing material may include silver brazing (e.g., Bag-8, Bag-9).

[0024] The number of brazing portions 5 may be one or a plurality. The number of brazing portions 5 may be the same as the number of conduction pins 2. When there are a plurality of brazing portions 5, the plurality of brazing portions 5 are located apart from each other.

[0025] As in the example shown in FIG. 2, when the number of brazing portions 5 is three, the three brazing portions 5 may be conveniently referred to as the first brazing portion 51, the second brazing portion 52, and the third brazing portion 53. The same applies to the conduction pin 2 and the through hole 31 in these respects.

[0026] Here, as in the example shown in FIGS. 3 and 4, the insulating member 3 includes a base portion 35 located in the internal space of the annular member 4, and an extension portion 36 extending from the base portion 35 toward the low-voltage side A2. The outermost diameter D1 of the base portion 35 is larger than the outermost diameter D2 of the extension portion 36. In these cases, since the spatial distance and the creepage distance between the conduction pin 2 and the annular member 4 on the low-voltage side A2 become longer, the withstand voltage can be increased. In addition, since the low-voltage side A2 of the base portion 35 can be directly attached to the metal annular member 4 by brazing or the like, the pressure resistance can be increased.

[0027] Note that the outermost diameter D1 and the outermost diameter D2 are not limited to specific values. For example, the outermost diameter D1 may be set to about 20 mm or more and 30 mm or less. Also, the outermost diameter D2 may be set to about 15 mm or more and 20 mm or less.

[0028] The numerical value of the length L1 (mm) of the extension portion 36 in the axial direction of the axis S may be 1 / 400 times or more of the numerical value of the potential difference (V / mm) generated between the annular member 4 and the conduction pin 2. In this case, since the spatial distance and the creepage distance between the outer peripheral surface of the conduction pin 2 exposed on the low-voltage side A2 and the surface of the annular member 4 closest to the outer peripheral surface of the conduction pin 2 can be made longer, the withstand voltage can be further increased.

[0029] Incidentally, the numerical value of the length L1 (mm) of the extension portion 36 in the axial direction of the axis S may be 1 / 100 times or more of the numerical value of the potential difference (V / mm) generated between the annular member 4 and the conduction pin 2. The potential difference (V / mm) may be measured, for example, by a withstand voltage tester.

[0030] The length L1 of the extension portion 36 in the axial direction of the axis S may be 7 mm or more. In this case, since the spatial distance and the creepage distance between the outer peripheral surface of the conduction pin 2 exposed on the low-voltage side A2 and the surface of the annular member 4 closest to the outer peripheral surface of the conduction pin 2 can be made longer, the withstand voltage can be further increased. Incidentally, the upper limit value of the length L1 may be 12 mm.

[0031] The length L1 of the extension portion 36 in the axial direction of the axis S may be longer than the length L2 of the base portion 35 in the axial direction of the axis S. In this case, since the spatial distance and the creepage distance between the conduction pin 2 and the annular member 4 on the low-voltage side A2 become longer, the withstand voltage can be increased. Incidentally, the length L2 is not limited to a specific value. For example, the length L2 may be set to about 7 mm or more and 12 mm or less.

[0032] As shown in an example in FIG. 5, the outer surface 361 of the extending portion 36 may be inclined toward the low-pressure side A2. In other words, the outer surface 361 of the extending portion 36 may be an inclined surface that inclines so as to approach the axis S of the insulating member 3 as it goes toward the main surface 33 of the low-pressure side A2. The angle θ formed by the outer surface 361 of the extending portion 36 and the axis S of the insulating member 3 may be an acute angle. In these cases, for example, when manufacturing the insulating member 3 by uniaxial press molding, cold isostatic pressing (CIP) molding, etc., demolding becomes easy, and cracks are less likely to occur when taking out the molded body. Therefore, even if the temperature increase and decrease are repeated, the propagation of cracks is suppressed.

[0033] Note that the angle θ is not limited to a specific value. For example, the angle θ may be set to about 2° or more and 3° or less. When evaluating the angle θ, a virtual axis S' parallel to the axis S may be used as a reference.

[0034] The outer surface 361 of the extending portion 36 may have a small average value of the cutting level difference (Rδc) representing the difference between the cutting level at a 25% load length rate and the cutting level at a 75% load length rate in the roughness curve, compared to the main surface 32 on the high-pressure side A1 of the insulating member 3.

[0035] When the average value of the cutting level difference (Rδc) of the outer surface 361 is smaller than the average value of the cutting level difference (Rδc) of the main surface 32, when the outer surface 361 is held by a holding member (not shown), the detachment of particles that are likely to occur during holding can be reduced. Here, the particles are a plurality of solid fine particles in which a part of the crystal constituting the sintered body detaches into space when an aluminum oxide-based sintered body or the like is used as the insulating member 3. Since the detachment of such particles is reduced, the floating of the particles detached in the space on the low-pressure side A2 (for example, a vacuum space) is suppressed. On the other hand, since the average value of the cutting level difference (Rδc) of the main surface 32 is larger than the average value of the cutting level difference (Rδc) of the outer surface 361, the extended surface distance between the conduction pins 2 becomes longer, and the risk of dielectric breakdown is reduced.

[0036] The average value of the cutting level difference (Rδc) of the main surface 32 may be 1 μm or more and 2.2 μm or less, or may be 1 μm or more and 1.9 μm or less.

[0037] The difference (ΔRδc) between the average value of the cutting level difference (Rδc) of the outer surface 361 and the average value of the cutting level difference (Rδc) of the main surface 32 is, for example, 0.2 μm or more and 0.7 μm or less.

[0038] The cutting level difference (Rδc) may be measured, for example, in accordance with JIS B 0601:2001. As follows, four lines to be measured are drawn at substantially equal intervals in each of three measurement ranges on each of the outer surface 361 and the main surface 32, and the line roughness is measured. The average value of 12 measured values for each of the outer surface 361 and the main surface 32 may be calculated. The measurement conditions may be set as follows, for example. Measuring instrument: Shape analysis laser microscope ("VK-X1100" manufactured by Keyence Corporation or its successor model) Illumination: Coaxial epi-illumination Cutoff value λs: None Cutoff value λc: 0.08 mm Cutoff value λf: None Correction for end effect: Yes Magnification: 240 times (10×24) Surface shape correction: Waviness removal Strength of correction: 5 Setting of height threshold: Ignore micro area (103.34 μm 2 ) Measurement location: Three locations each on the outer surface 361 and the main surface 32 Measurement range: 1428 μm × 1071 μm / one location Length of line to be measured: 1280 μm / one line

[0039] The shape of the extension part 36 may be frustum-shaped. For example, when the shape of the extension part 36 is frustum-shaped with a pyramid, stress concentration is likely to occur on the side, but when it is frustum-shaped, there is no side, so stress concentration is less likely to occur. Therefore, the extension part 36 is less likely to be damaged.

[0040] The base 35 may include a small-diameter portion 351 and a large-diameter portion 352. The small-diameter portion 351 may be located on the high-pressure side A1. The large-diameter portion 352 may be located on the low-pressure side A2. More specifically, the large-diameter portion 352 may be located on the low-pressure side A2 rather than the small-diameter portion 351. Also, the outer diameter D4 of the large-diameter portion 352 may be larger than the outer diameter D3 of the small-diameter portion 351.

[0041] When the base 35 includes the above-described small-diameter portion 351 and large-diameter portion 352, a stepped surface 353 that connects the outer peripheral surface of the small-diameter portion 351 and the outer peripheral surface of the large-diameter portion 352 is formed. In other words, the base 35 includes a stepped surface 353 that connects the outer peripheral surface of the small-diameter portion 351 and the outer peripheral surface of the large-diameter portion 352. Due to the presence of this stepped surface 353, the creepage distance between the conduction pin 2 and the annular member 4 on the high-pressure side A1 becomes longer, so the withstand voltage can be increased. Note that the outer diameter D4 of the large-diameter portion 352 may be the outermost diameter D1 of the base 35. Also, the outer diameter D3 of the small-diameter portion 351 may be larger than the outermost diameter D2 of the extension portion 36. When the outer diameter D3 is larger than the outermost diameter D2, the strength of the base 35 is high.

[0042] The length L3 of the small-diameter portion 351 in the axial S direction may be shorter than the length L4 of the large-diameter portion 352 in the axial S direction. In this case, since the length L4 of the large-diameter portion 352 in the axial S direction becomes relatively long, the strength of the base 35 is high.

[0043] <Compressor> Next, a compressor according to a non-limiting embodiment of the present disclosure will be described with reference to the drawings, taking the case of including the above-described hermetic terminal 1 as an example.

[0044] As shown in an example in FIG. 6, the compressor 100 includes a casing 101 (pressure-resistant container) and a hermetic terminal 1. The casing 101 houses a motor 102 for compressing a refrigerant. The hermetic terminal 1 is attached to the casing 101. Electric power from an external power source 103 is supplied to the motor 102 via the conduction pin 2. In these cases, since the compressor 100 includes the hermetic terminal 1 having high withstand voltage and pressure resistance, stable operation over a long period is possible.

[0045] The hermetic terminal 1 may be attached to the casing 101 by welding, for example. The motor 102 may be a three-phase motor, for example. The external power supply 103 may be a three-phase AC power supply, for example. The motor 102 and the external power supply 103 may be electrically connected to the conduction pin 2 via the wiring 104.

[0046] The compressor 100 may include a compression mechanism 105, a suction pipe 106, and a discharge pipe 107. The compression mechanism 105 is housed in the casing 101. The suction pipe 106 and the discharge pipe 107 are attached to the casing 101. The suction pipe 106 and the discharge pipe 107 may be attached to the casing 101 by welding, for example.

[0047] The compression mechanism 105 is driven by the motor 102 and compresses the refrigerant. The suction pipe 106 sends the refrigerant to the compression mechanism 105. The discharge pipe 107 discharges the refrigerant compressed by the compression mechanism 105 and sends it out to the refrigerant circulation system.

[0048] When the compressor 100 includes the above-described compression mechanism 105, suction pipe 106, and discharge pipe 107, power from the external power supply 103 is supplied to the motor 102 via the hermetic terminal 1, and the compression mechanism 105 can compress the refrigerant by driving the motor 102. Further, the refrigerant flows into the compression mechanism 105 from the suction pipe 106, and the compressed refrigerant flows out from the discharge pipe 107 and is sent to the refrigerant circulation system.

[0049] As described above, the embodiments according to the present disclosure have been illustrated. Needless to say, the present disclosure is not limited to the above-described embodiments and can be arbitrarily modified without departing from the gist of the present disclosure.

[0050] For example, in the above embodiment, the case where the hermetic terminal 1 is for a compressor used in a refrigerator has been described as an example. However, the hermetic terminal 1 is also applicable to other uses. Examples of other uses include, for example, a sensor unit, an aluminum electrolytic capacitor, a relay contact device, a medical device, a storage device, a compressor driven by an electric motor used in a hybrid vehicle or an electric vehicle, and the like.

Explanation of Signs

[0051] 1 ··· Hermetic terminal 2 ··· Conductive pin 3 ··· Insulating member 31 ··· Through hole 32 ··· Main surface on the high-pressure side 33 ··· Main surface on the low-pressure side 34 ··· Convex portion 341 ··· Convex surface 35 ··· Base portion 351 ··· Small-diameter portion 352 ··· Large-diameter portion 353 ··· Step surface 36 ··· Extending portion 361 ··· Outer surface 4 ··· Annular member 5 ··· Brazed portion 51 ··· First brazed portion 52 ··· Second brazed portion 53 ··· Third brazed portion 100 ··· Compressor 101 ··· Casing 102 ··· Motor 103 ··· External power supply 104 ··· Wiring 105 ··· Compression mechanism 106 ··· Suction pipe 107 ··· Discharge pipe S ··· Shaft A1 ··· High-pressure side A2 ··· Low-pressure side

Claims

1. A conduction pin, a columnar insulating member having through holes that open to the high-pressure side and the low-pressure side and are for inserting the conduction pin, an annular member made of metal that surrounds the insulating member, and a brazing portion that fixes the conduction pin to the main surface on the high-pressure side of the insulating member or the convex surface of a convex portion provided on the main surface, and is a hermetic terminal, wherein the insulating member comprises a base portion located in the internal space of the annular member, and an extension portion extending from the base portion toward the low-pressure side, the outermost diameter of the base portion is larger than the outermost diameter of the extension portion, the side surface of the extension portion facing the annular member is separated from the annular member, and the distance between the side surface and the annular member is longer than the distance between the side surface and the conduction pin, wherein the base portion comprises a small-diameter portion located on the high-pressure side, and a large-diameter portion located on the low-pressure side and having an outer diameter larger than that of the small-diameter portion, and the outermost diameter of the small-diameter portion is larger than the outermost diameter of the extension portion, the hermetic terminal.

2. The numerical value of the axial length (mm) of the extension portion is 1 / 400 times or more of the numerical value of the potential difference (V / mm) generated between the annular member and the conduction pin, the hermetic terminal according to Claim 1.

3. The axial length of the extension portion is 7 mm or more, the hermetic terminal according to Claim 1 or 2.

4. The outer surface of the extension portion is inclined toward the low-pressure side, and the angle formed with the axis of the insulating member is an acute angle, the hermetic terminal according to Claim 1 or 2.

5. The outer surface of the extension portion has a small average value of the cutting level difference (Rδc) representing the difference between the cutting level at 25% load length rate and the cutting level at 75% load length rate in the roughness curve, compared to the main surface on the high-pressure side of the insulating member, the hermetic terminal according to Claim 1 or 2.

6. The shape of the extension portion is a frustum of a cone, the hermetic terminal according to Claim 1 or 2.

7. a casing that houses a motor for compressing a refrigerant, and the hermetic terminal according to Claim 1 or 2 attached to the casing, a compressor that supplies electric power from an external power source to the motor via the conduction pin.

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