Patent Application
20050163630
The present invention relates to a compressor, and more particularly, to a compressor that has a terminal for conducting external electricity to a motor mechanism accommodated in a housing member.
The conductive portion 96 includes leads 97 connected to the motor mechanism 95 and a terminal 98 that contacts the leads 97. A through hole 93a is formed in the housing member 93. The terminal 98 is press fitted in the through hole 93a. A joint 99 between the terminal 98 and the leads 97 is buried in epoxy resin P, which is an insulating material. The epoxy resin P, in which the joint 99 between the terminal 98 and the leads 97 is buried, is first in a liquid state, but is hardened as time elapses. The hardened epoxy resin P improves the insulating performance of the terminal 98 and the leads 97, thereby preventing leakage of current in the electrical system (for example, refer to Japanese Laid-Open Patent Publication No. 6-235388).
In the above described prior art, operation of the compressor 90 increases the temperature of the compressor 90. When the operation is stopped, the temperature of the compressor 90 drops. As the temperature of the compressor 90 is increased and lowered, portions of the compressor (for example, the housing members 91 to 93) are heated and cooled. Accordingly, the portions of the compressor expand and shrink.
Expansion and shrinkage of the portions of the compressor 90 are dominated by the thermal expansion coefficient of the materials forming the portions. Since the thermal expansion coefficient of the housing members 91 to 93 is different from that of the epoxy resin P, minute spaces can be created between the contacting surfaces of the housing member 93 and the epoxy resin P when the compressor 90 is cooled and the portions shrink. Also, since the thermal expansion coefficient of the epoxy resin P is different from that of the leads 97, minute spaces can be created between the contacting surfaces of the leads 97 and the epoxy resin P.
When water is caught inside the housing members 91 to 93, the water can enter the minute spaces due to capillarity. If the water reaches the joint between the terminal 98 and the leads 97, the insulation of the terminal 98 can deteriorate.
Accordingly, it is an objective of the present invention to provide a compressor that ensures reliable insulation of a terminal from a housing member.
To achieve the above-mentioned objective, the present invention provides a compressor. The compressor includes a housing member forming a shell of the compressor. The housing member has a through hole. A compression mechanism compresses drawn gas. A motor mechanism drives the compression mechanism. The compressor includes a conductive portion through which external electricity is supplied to the motor mechanism. The conductive portion has a lead extending from the motor mechanism, and a connector terminal. The connector terminal is connected to the lead to permit the external electricity to be conducted to the lead. The connector terminal is attached to the through hole such that a joint between the lead and the connector terminal is located in the through hole to face inward of the housing member. A viscoelastic insulating material fills the through hole.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
FIGS. 5(a) to 5(c) are cross-sectional views illustrating first to third modifications of the through hole shown in
A compressor 10 according to a first embodiment of the present invention will now be described with reference to FIGS. 1 to 3. The compressor 10 of this embodiment is a scroll compressor and is categorized in the field of hermetic electric compressors. Specifically, the compressor 10 is a scroll compressor for a fuel cell (hereinafter, simply referred to as a compressor).
The compressor 10 shown in
The compression mechanism of the compressor 10 includes a fixed scroll 11, an orbiting scroll 12, and compression chambers 13 defined by the fixed scroll 11 and the orbiting scroll 12. The fixed scroll 11 has a disk-shaped fixed base plate 11a, a spiral fixed wrap 11b projecting from the fixed base plate 11a, and an outermost wall 11c of the fixed wrap 11b. The fixed base plate 11a and the fixed wrap outermost wall 11c form a fixed scroll housing member 16. The fixed scroll housing member 16 forms a part of the shell of the compressor 10. In this embodiment, the fixed scroll housing member 16 is made of an aluminum based metal material to reduce the weight of the compressor 10.
A suction passage 14 for conducting air into the compression chambers 13 is formed in the fixed scroll housing member 16. A discharge passage 15 is formed in the center of the fixed base plate 11a. The discharge passage 15 is connected to an oxygen electrode of the fuel cell through a discharge pipe.
The orbiting scroll 12 includes a disk-shaped orbiting base plate 12a and a spiral orbiting wrap 12b protruding from the orbiting base plate 12a. A cup-shaped main support portion 12c for holding a roller bearing 17 is formed in the center of the orbiting base plate 12a at the rear side. Three cup-shaped subordinate support portions 12d (only one of them is shown in
The driving mechanism of the compressor 10 includes a driving crank mechanism 19 for causing the orbiting scroll 12 to orbit, and a follower crank mechanism 20 for preventing the orbiting scroll 12 from rotating, and a crank chamber 21 for accommodating the crank mechanisms 19, 20. The crank chamber 21 is connected to the suction passage 14, and the crank chamber 21 is filled with air drawn through the suction passage 14. The driving crank mechanism 19 includes the main support portion 12c, a crank pin 22a of a drive shaft 22, and the roller bearing 17 that supports the crank pin 22a. The follower crank mechanism 20 includes the subordinate support portions 12d and the radial ball bearings 18 that support crank pins 23a of follower shafts 23. The rear side of the follower shafts 23 is supported by ball bearings 23c.
To cancel moment of inertial generated by orbiting motion of the orbiting scroll 12, balance weights 22b, 22c, 22d are provided on the drive shaft 22, and a balance weight 23b is provided on each follower shaft 23. This reduces vibration.
The motor mechanism includes a center housing member 24, a rear housing member 25 fixed to the center housing member 24 with bolts, a motor chamber 27 located between the housing members 24 and 25, and a drive motor 26. The drive motor 26 is accommodated in the motor chamber 27. The drive motor 26 is a synchronous motor that includes the drive shaft 22 that extends through a center of the motor 26, a rotor 28 fitted around the drive shaft 22, and a stator 30, around which a coil 29 is wound. The performance of the drive motor 26, for example, rotation speed, is therefore controllable with an unillustrated inverter. The coil 29 of the motor 26 is connected to a conductive portion 33. External electricity is supplied to the drive motor 26 through the conductive portion 33.
A front portion of the drive shaft 22 is supported by a ball bearing 22e. The drive shaft 22 is also supported by a ball bearing 22f at a center portion of the rear housing member 25. The rear end of the drive shaft 22 is sealed with a seal 22g.
Further, the center housing member 24, which covers the drive motor 26, has a water jacket 31, the position of which corresponds to the position of the stator 30. Coolant is conducted to the water jacket 31 to cool the drive motor 26. The center housing member 24 and the rear housing member 25 coupled to the center housing member 24 are housing members forming a part of the shell of the compressor 10 together with the fixed scroll housing member 16. In this embodiment, the center housing member 24 and the rear housing member 25 are made of an aluminum based metal material to reduce the weight of the compressor 10.
The motor mechanism is accommodated in the center housing member 24 together with the drive mechanism. A support frame 32 is integrally formed with the center housing member 24 substantially at the center to separate the drive mechanism and the motor mechanism from each other. The ball bearing 22e and the ball bearings 23c are fitted in the support frame 32. The support frame 32 separates the drive mechanism and the motor mechanism from each other except for a space between the circumferential surface of the drive shaft 22 and the ball bearing 22e and a space between the circumferential surface of each follower shaft 23 and the corresponding ball bearing 23c.
The conductive portion 33 of the motor mechanism will now be described.
It has already been described above that the conductive portion 33 functions to conduct external electricity to the drive motor 26. The conductive portion 33 of this embodiment includes leads 34 and a hermetic terminal 35 as shown in
As shown in
The hermetic terminal 35 constructed as described is attached to the attachment portion 40a of the through hole 40. The hermetic terminal 35 is attached to the attachment portion 40a to seal the center housing member 24 with the O-ring 37 attached to the cap body 36.
When the hermetic terminal 35 is attached to the through hole 40, each terminal pin 38 includes an outer end 38a protruding outward from the center housing member 24 and an inner end 38b extending inward of the center housing member 24 from the cap body 36. The outer ends 38a of the terminal pins 38 are located outside of the center housing member 24. The outer ends 38a is connected to an external power supply with an unillustrated connector. The inner ends 38b of the terminal pins 38 are located inside the through hole 40. Each inner end 38b is connected to one of the leads 34, which are connected to the coil 29 of the drive motor 26. Therefore, the joints 41 between the terminal pins 38 and the inner ends 38b are located inside the through hole 40. In other words, the hermetic terminal 35 is fitted in the through hole 40 such that the joints 41 between the leads 34 and the hermetic terminal 35 are located in the through hole 40 while facing inward of the center housing member 24. Portions of each lead 34 except the joint 41 are covered with the insulating coating 34a.
In this embodiment, a portion of the through hole 40 that is located inward of the attachment portion 40a is filled with a viscoelastic insulating material M. The insulating material M fills the through hole 40 of the center housing member 24. Therefore, the insulating material M filling the through hole 40 buries the joints 41 between the hermetic terminal 35 and the leads 34. A material having viscoelasticity is viscous to an object that contacts the material and elastic to external force. Specifically, the viscoelastic insulating material M in this embodiment is an elastic silicone resin, which is viscous to objects that contact the resin and elastic to external force. The elastic silicone resin is first in a liquid state, but gradually hardened as it is exposed to air. When hardened, the elastic silicone resin has a certain viscoelasticity. The insulating material M is injected into the through hole 40 from the inside of the center housing member 24.
Operation of the compressor 10 of this embodiment will now be described.
When the compressor 10 is driven, drawn air is compressed in the compression chambers 13. The compressed air is discharged through the discharge passage 15. Heat generated due to compression of drawn air increases the temperature of the compressor 10. When stopped in a heated state, the compressor 10 is cooled. As the compressor 10 is cooled, portions of the compressor 10 shrink as a result of cooling. At this time, the center housing member 24 also shrinks and tends to narrow the through hole 40. The viscoelastic insulating material M that fills the through hole 40 also shrinks to reduce the volume. The degrees of shrinkage of the center housing member 24 and the viscoelastic insulating material M are different according to the thermal expansion coefficient of the components forming the center housing member 24 and the material M. In general, it is known that resin (viscoelastic insulating material M) has a greater thermal expansion coefficient. Therefore, at contacting surfaces between the center housing member 24 and the insulating material M, the center housing member 24 and the insulating material M tend to separate from each other due to shrinkage from cooling.
However, since the insulating material M filling the through hole 40 has viscoelasticity, the insulating material M keeps contacting the center housing member 24 even if the thermal expansion coefficient is different between the center housing member 24 and the material M. That is, the elasticity of the insulating material M accommodates the difference in shrinkage between the center housing member 24 and the insulating material M, and the viscosity of the insulating material M keeps the adhesion between the center housing member 24 and the insulating material M. Therefore, no space is created between the center housing member 24 and the insulating material M, and sealed state is maintained. At contacting surfaces between the leads 34 and the insulating material M also, no space is created, and a sealed state is maintained.
In this manner, the sealing state is maintained for members contacting the insulating material M. Thus, even if water is caught inside the center housing member 24, the water is prevented from reaching the joints 41 between the hermetic terminal 35 and the leads 34. Accordingly, the hermetic terminal 35 is maintained as insulated from the center housing member 24.
It has already been described above that the temperature of the compressor 10 is increased as the compressor 10 is driven. Thermal expansion varies among portions of the compressor 10. Thermal expansion of the center housing member 24, the hermetic terminal 35, and the leads 34, which contact the insulating member M, is accommodated by the insulating material M. The insulating material M therefore maintains adhesion to the center housing member 24, the hermetic terminal 35, and the leads 34.
Thus, even if the temperature of the compressor 10 is increased, water inside the center housing member 24 does not reach the joints 41 between the hermetic terminal 35 and the leads 34.
Further, since the insulating material M has viscoelasticity, the insulating material M absorbs vibration of the compressor 10 during operation. Thus, space is not created in the contacting surfaces of the center housing members 24, the hermetic terminal 35, and the leads 34, which contact the insulating material M.
The O-ring 37, which functions as a sealing member, is attached to the circumferential surface of the cap body 36 of the hermetic terminal 35. The O-ring 37 maintains the sealed state of the through hole 40. Therefore, water that tends to enter the through hole 40 from the outside of the center housing member 24, is blocked by the O-ring 37.
The compressor 10 according to this embodiment provides the following advantages.
(1) The joints 41 between the leads 34 and the hermetic terminal 35 are buried in the viscoelastic insulating material M. Therefore, when the compressor 10 is cooled, minute spaces that tend to be present between the insulating material M and the housing member (center housing member 24), the leads 34, or the hermetic terminal 35 are accommodated by the elasticity of the insulating material M. The viscosity of the insulating material M causes the contacting surfaces between the insulating material M and the center housing member 24, the leads 34, or the hermetic terminal 35 to be adhered to each other. Water is prevented from entering such contacting surfaces.
(2) The joints 41 between the leads 34 and the hermetic terminal 35 are buried in the viscoelastic insulating material M. Therefore, even if portions of the compressor 10 vibrate due to operation of the compressor 10, the vibration is absorbed by the viscoelasticity of the insulating material M. Thus, no minute spaces are created in the contacting surfaces between the insulating material M and the center housing member 24, the leads 34, or the hermetic terminal 35.
(3) The joints 41 between the leads 34 and the hermetic terminal 35 are buried in the viscoelastic insulating material M. Thus, when the insulating material M receives vibration due to operation of the compressor 10, cracks are not created. Also, even if the insulating material M repeatedly receives thermal stress due to increase and drop of the temperature of the compressor 10, the insulating material M is not damaged.
(4) The joints 41 between the leads 34 and the hermetic terminal 35 are buried in the viscoelastic insulating material M. Therefore, air inside the center housing member 24 does not leak to the connector terminal (the hermetic terminal 35) through the through hole 40 of the center housing member 24.
(5) The hermetic terminal 35 is attached to the attachment portion 40a, which is formed at an outer portion of the through hole 40 with respect to the compressor 10. That is, the hermetic terminal 35 is fixed to the center housing member 24 to cover the through hole 40 from the outside. This causes the joints 41 between the hermetic terminal 35 and the leads 34 to face inward of the center housing member 24. Therefore, a space is defined in the through hole 40, which space can be filled with a sufficient amount of the insulating material M from the inside of the center housing member 24.
(6) In this embodiment, the connector terminal that conducts external electricity and is connected to the leads 34 is the hermetic terminal 35. Therefore, the leads 34 are insulated from the center housing member 24 with a relatively simple structure.
A compressor 50 according to a second embodiment of the present invention will now be described.
The compressor 50 of this embodiment is substantially the same as the compressor 10 of the previous embodiment, except for that, together with the viscoelastic insulating material M, an insulating material N that is different from the material M is provided. Hereinafter, the material N will sometimes be referred to as a dissimilar insulating material N for purposes of illustration. In this embodiment, for purposes of illustration, the entirety of the compressor 50 is not shown, but part of the compressor 50 is shown in
In this embodiment, the hermetic terminal 35 is attached to a through hole 52 formed in a center housing member 51 of the compressor 50. The joints 41 between the hermetic terminal 35 and the leads 34 are located inside the through hole 52. In this embodiment, the two kinds of insulating materials M, N are layered in the through hole 52. The dissimilar insulating material N is located between the viscoelastic insulating material M and the attachment portion 40a.
The dissimilar insulating material N fills a portion of the through hole 52 that is inward of the attachment portion 40a and outward of the insulating material M. The dissimilar insulating material N is different from the viscoelastic insulating material M. Specifically, the dissimilar insulating material N is a cured resin such as an epoxy resin. The dissimilar insulating material N fills a portion of the through hole 52 that is inward of the attachment portion 40a and outward of the inner end of the through hole 52. In other words, the dissimilar insulating material N fills the through hole 52 in a portion that is inward of the cap body 36 of the hermetic terminal 35, but does not completely fill the through hole 52. The joints 41 between the terminal pins 38 and the leads 34 are buried in the dissimilar insulating material N.
The viscoelastic insulating material M fills a portion of the through hole 52 that is inward of the dissimilar insulating material N. In other words, the viscoelastic insulating material M, together with the dissimilar insulating material N, completely fills the through hole 52. The viscoelastic insulating material M only contacts the dissimilar insulating material N, which is a cured resin, the center housing member 51, and the leads 34 (specifically, the insulating coating 34a).
In the compressor 50 of this embodiment, the hermetic terminal 35 attached to the through hole 52 is insulated from the center housing member 51 by the insulating properties of the hermetic terminal 35, the dissimilar insulating material N, which is a cured resin, and the viscoelastic insulating material M. Even if portions of the compressor 50 shrink due to cooling, the viscoelastic insulating material M filling an inner portion of the through hole 52 does not create spaces with, but maintains adhesion with the dissimilar insulating material N, the center housing member 51, and the leads 34, which contact the viscoelastic insulating material M.
The compressor 50 according to this embodiment provides the following advantages.
(1) Since the dissimilar insulating material N and the viscoelastic insulating material M are used in combination, the amount of the viscoelastic insulating material M is reduced. Accordingly, the manufacturing cost of the compressor 50 is reduced. This advantage is particularly pronounced when the viscoelastic insulating material M is expensive.
(2) The dissimilar insulating material N, which is a cured resin filling a part of the through hole 52, contacts the cap body 36 of the hermetic terminal 35. This reinforces the adhesion of the hermetic terminal 35 to the center housing member 51.
A first to third modification of the through hole 40 formed in a compressor center housing member 24 according to the first embodiment will now be described with reference to FIGS. 5(a) to 5(c). For purposes of illustration, the same reference numerals are used for the hermetic terminal 35, the leads 34, and the joints 41.
A first modification will now be described. As shown in
A second modification will now be described. As shown in
Lastly, a third modification will be described. As shown in
According to the first to third modifications, the length of the through hole 62, 72, 82 is elongated by forming at least one of the outer boss 63, 84 and the inner boss 73, 83 around the through hole 62, 72, 82, so that a sufficient amount of the viscoelastic insulating material M fills the through hole 62, 72, 82. In other words, a space for accommodating a sufficient amount of the viscoelastic insulating material M is formed. Filling the space with the insulating material M, the hermetic terminal 35 is further reliably insulated from the center housing member 61, 71, 81. Forming at least one of the outer boss 63, 84 and the inner boss 73, 83 facilitates setting of the amount of the viscoelastic insulating material M according to the conditions in which the compressor 10 is used. In the first to third modification, the viscoelastic insulating material M may be used with the dissimilar insulating material N as described in the second embodiment.
The invention may be embodied in the following forms.
In the first and second embodiments, the compressors are scroll compressors. However, the present invention may be applied to any form or type of hermetic electric compressor that has a motor mechanism accommodated in a housing member. For example, the present invention may be applied to a roots type compressor.
In the first and second embodiments, an elastic silicone resin is used as the viscoelastic insulating material M. However, any resin or rubber material having an insulating property and viscoelasticity may be used as the insulating material M. In a case of a compressor connected to a fuel cell, the viscoelastic insulating material M preferably has acid resistance.
In the first and second embodiments, the through hole 40 is formed in the center housing member 24, 51 of the compressor, and the hermetic terminal 35, which is the connector terminal, is attached to the through hole 40, 52. However, a housing member to which the hermetic terminal 35 is attached is not limited to the center housing member 24, 51. For example, a through hole may be formed in the rear housing member 25 and the hermetic terminal 35 may be fitted to the through hole. The through hole 40 to which the hermetic terminal 35 is attached may be formed in any housing member that forms the shell of the compressor.
In the first and second embodiments, the O-ring 37, which functions as a sealing member, is attached to the cap body 36 of the hermetic terminal 35, which functions as a connector terminal. However, the sealing member is not limited to the O-ring 37, but may be any type or shape as long as it has a sealing property.
The present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-015163 | Jan 2004 | JP | national |
