JP3754237B2 - Peripheral drive scroll compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reciprocating positive displacement compressor that compresses gas while reducing the volume of a compression working chamber by a revolving motion of one rotor, and particularly a crescent-shaped compression by a scroll member configured in a spiral shape. The present invention relates to a scroll compressor having a feature that a plurality of chambers are formed.
[0002]
[Prior art]
The basic operation principle of the scroll compressor will be described. This compressor engages two scroll members, each of which is provided with an upright spiral wrap on the end plate, and engages with each other so that one scroll member is constrained from rotating with respect to the other scroll member. In this manner, the size of the compression working chamber constituted by the scroll members is sequentially changed, and by turning the orbiting scroll, gas is transferred from the outer peripheral portion to the center portion of the scroll member. It is what is compressed.
[0003]
This type of scroll compressor has a structure in which the orbiting scroll and the fixed scroll receive a force separating from each other due to the gas pressure in the compression chamber constituted by the scroll wrap, and there are wraps on both sides of the orbiting scroll end plate. There is a structure in which a compression working chamber is formed on each surface to cancel the thrust force caused by the compressed gas acting on the orbiting scroll.
[0004]
A known technique close to the present invention is the latter technique, which is disclosed, for example, in JP-A-7-310682. According to this known technique, the orbiting scroll disposed between a pair of fixed scrolls and having scroll wraps disposed on both sides of the end plate is driven by a plurality of drive shafts having eccentric portions provided on the outer periphery thereof. Thus, the orbiting scroll is configured to smoothly perform the orbiting motion and perform the compression operation.
[0005]
As a basic design philosophy in a compressor having a structure in which compression chambers are formed on both sides of the end plate of the orbiting scroll as in the known art, setting of a gap when forming the compression working chamber, in particular, a shaft formed on the lap tip surface In many cases, the directional gap is set in substantially the same manner for the compression working chambers formed on both sides of the swivel end plate.
[0006]
According to the known technique, both the orbiting scroll and the pair of fixed scrolls are made of aluminum alloy or the like. On the other hand, the materials of the plurality of drive shafts arranged on the outer periphery of the scroll are not clearly shown, but in general, mechanical parts that receive driving force in response to load fluctuations are made of ferrous metal materials. There are many.
[0007]
Further, the compression working chambers configured on both sides of the orbiting scroll are configured to have the same size, and the thrust force due to the gas pressure generated when the gas is compressed is equalized. In addition, since no lubricating oil is mixed in the compression working chamber, the wrap end surfaces of both scrolls are made of a resin material mainly composed of a tetrafluoroethylene resin material in order to maintain high compression performance. A sealing member, that is, a chip seal is attached.
[0008]
[Problems to be solved by the invention]
In the above-described conventional technology, the orbiting scroll is configured to be positioned and supported with respect to the fixed scroll by the plurality of drive shafts arranged on the outer peripheral portion, and thus the following problems occur. That is, as the scroll compressor starts the compression operation, the gas is adiabatically compressed, so that the discharge gas increases in pressure and becomes hot. Compressor components including the scroll member are heated by the high-temperature compressed gas, and become a high-temperature state. The drive component is also heated by a frictional force generated by rotation of a bearing or the like.
[0009]
On the other hand, since the orbiting scroll is positioned and supported by the drive shaft on the outer periphery, the relative positional relationship with the fixed scroll is properly maintained. However, when the compressor is operated, all parts are heated as described above, and the driving time shaft is also heated in the same manner. As a result, when the drive shaft is thermally expanded, the orbiting scroll supported by the drive shaft is also moved in the axial direction by the thermal expansion of the drive shaft. Therefore, there is a problem that the relative positional relationship between the orbiting scroll and the fixed scroll is shifted.
[0010]
Fixed scrolls are arranged on both sides of the end plate of the orbiting scroll, and compression working chambers are formed on both sides of the end plate. In one compression working chamber, the axial gap between both scrolls is enlarged, and the other In the compression working chamber, the axial clearance between the scrolls is reduced. In such a situation, on the side where the axial clearance is enlarged, the leakage of compressed gas between the compression working chambers becomes large, causing a decrease in compressor performance. Furthermore, the recompression of the leaking gas further increases the temperature of the high-pressure side gas, which may increase the amount of deformation of the scroll member and the like.
[0011]
On the other hand, on the side where the axial gap between the scroll wraps is reduced, there is a possibility that the gap may be reduced more than that which was conceived at the time of design. In such a state, the chip seal is adversely affected. That is, since the high pressure compressed gas usually acts on the back surface of the tip seal itself, the force is used as a sealing force to prevent the compressed gas from leaking at the tip.
[0012]
However, since this type of chip seal material has a linear expansion coefficient that is about 3 to 5 times that of an aluminum alloy, the chip seal mounting groove fills up when the chip seal itself is heated and thermally expanded. It can't be squeezed out and it starts to protrude outside. At this time, since the tip seal tip surface and the tooth bottom surface of the mating scroll are in contact with each other due to the pressure on the back surface of the chip seal, the space on the back surface of the chip seal is reduced when thermally expanded.
[0013]
As the thermal expansion proceeds, the space decreases, and when the temperature rises above a certain temperature, the space disappears, and the tip seal tip surface comes into contact with the mating tooth bottom surface. When the thermal expansion further proceeds, there is no room for absorbing the thermal expansion, and the contact surface pressure at the tip seal tip surface increases abruptly.
[0014]
In most cases, the tip seal is made of a composite resin material, and since the tip seal slides in contact with the mating surface, wear of the tip seal itself is inevitable. However, if the seal surface pressure acting on the tip seal during the operation of the compressor is a contact surface pressure given by design, the tip seal is in a so-called mild wear state, so the wear speed is small and the seal performance is improved. On the other hand, sufficient functions can be demonstrated over a long period of time.
[0015]
Incidentally, the amount of wear of the tip seal is greatly influenced by the sliding speed of the sliding surface and the contact surface pressure. If the compressor as in the known technology is continuously operated without securing the necessary heat dissipation amount, a large thermal expansion occurs, and as described above, the orbiting scroll receives the thermal expansion of the shaft and moves to one fixed side. If the amount of thermal expansion of the tip seal itself is also added and comes into contact with the mating tooth bottom surface, the contact surface pressure of the tip seal rapidly increases. As a result, there is a possibility that so-called abnormal wear may occur, for example, the tip seal wear rate rapidly increases.
[0016]
Furthermore, if the amount of thermal expansion of the drive shaft becomes larger, the scroll wrap constructed on one side of the orbiting scroll end plate will approach the counterpart fixed scroll more than necessary, so there is a risk that the lap tip surface and the counterpart tooth bottom surface will come into direct contact. Will arise. Because the scroll member is made of aluminum alloy and contacts in a non-lubricated state, abnormal wear such as adhesive wear between the lap tip surface and the mating tooth bottom surface when a certain pressing force is applied. Since the state is caused and the scroll wrap is burned or broken, the function as the compressor is impaired.
[0017]
An object of the present invention is to eliminate the above-mentioned problems, and during operation of the compressor, the thrust gap between the compression working chambers formed on both sides of the orbiting scroll is preferably maintained, and the pressure state of both compression working chambers is maintained. An object of the present invention is to provide an outer periphery driven scroll compressor that can be kept equally stable.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the first means of the present invention is that there are fixed scrolls arranged in parallel, which are fixed to each other by flange surfaces and arranged so as to be contained inside. There is an orbiting scroll, compression working chambers are formed on both sides of the orbiting scroll mirror plate, and the orbiting scroll is configured to be supported while being positioned on the outer periphery of the orbiting scroll end plate by the drive shaft and auxiliary drive shaft. For the scroll compressor, considering the thermal expansion amount of the drive shaft driving the orbiting scroll and the auxiliary drive shaft and the thermal expansion amount of the scroll member, the compression working chamber formed on both sides of the orbiting scroll end plate, The compressor is configured such that the gap between the scroll wrap tip during assembly and the tooth bottom facing the tip is unbalanced in advance. Gap between the root surface facing the scroll wrap tip and the tip portion of the compression working chamber is to to be suitably maintained during operation.
[0019]
Further, since the second means of the present invention has a tip seal attached to each scroll wrap tip, the amount of thermal expansion of the drive shaft and auxiliary drive shaft for driving the orbiting scroll and the amount of thermal expansion of the scroll member are determined. In view of this, the amount of protrusion of the tip seals arranged on both sides of the orbiting scroll end plate is configured to be unbalanced during assembly, and the seal surface pressure of the tip seal during operation is maintained appropriately.
[0020]
In other words, the first means has been invented to avoid the following situation as described in the above problem. The drive shaft and the auxiliary drive shaft are assembled in a state of being fixed in the axial direction with respect to one of the fixed scrolls by bearings that rotate and support each of them, and the other fixed scroll against thermal expansion. It is assembled in a movable state in consideration of dimensional relief.
[0021]
Therefore, in the compression working chamber closer to the side where the drive shaft and the auxiliary drive shaft are fixedly supported, when the drive shaft and the auxiliary drive shaft are thermally expanded, the position of the orbiting scroll is separated from the fixed scroll by the amount of thermal expansion of the shaft. As a result, the gap between the tip end portion of the scroll wrap and the tooth bottom surface facing the tip end portion tends to increase.
[0022]
On the other hand, in the compression chamber closer to the side where the drive shaft and auxiliary drive shaft are movably supported, the orbiting scroll moves so as to approach the fixed scroll by the amount of relative thermal expansion of the shaft. As a result, the gap between the scroll wrap tip and the tooth bottom facing the tip tends to be small.
[0023]
Therefore, there are several methods for reducing the gap between the tip end of the scroll wrap and the tooth bottom surface facing the tip in the former case, that is, closer to the fixed side of the drive shaft. Second, there is a method of bringing the support position of the orbiting scroll closer to the fixed side of the bearing, and second, a method of increasing the height of the scroll wrap without changing the position of the orbiting scroll, or a method of raising the position of the bottom surface of the wrap, etc. There is.
[0024]
In the latter case, that is, in order to set a large gap between the scroll wrap front end and the tooth bottom surface facing the front end in advance, a method of fixing the fixed scroll slightly away from the orbiting scroll, as opposed to the above, Second, there is a method of reducing the height of the fixed scroll wrap without changing the position of the orbiting scroll, or a method of releasing the position of the bottom surface of the fixed side wrap without changing the position of the orbiting scroll.
[0025]
These set dimensions can be selected by design according to the size of the drive shaft and the temperature rise value of the compressor, but these physical quantities have a rough correlation with the approximate compressor capacity if the compression mechanism is determined.
[0026]
Here, as an example of the set dimensions, the compressor targeted in the present invention is an outer peripheral drive type scroll compressor, but this is used as a so-called oil-free machine that does not supply lubricating oil into the compression working chamber. As an example, the compressor capacity can be as small as about 0.15 mm to 0.05 mm in the class of 7.5 kW to 11 kW capacity.
[0027]
Next, as a second method, a case will be described in which adjustment is made by adjusting the amount of protrusion of the tip seal attached to the tip of the scroll wrap. That is, the above-mentioned dimension is an amount that can suppress the leakage of compressed gas by setting the chip seal. Therefore, on the side closer to the side where the drive shaft and auxiliary drive shaft are fixed to the fixed scroll, etc., this is achieved by reducing the depth of the tip seal mounting groove so that the tip seal can protrude more from the tip of the scroll wrap. Is done.
[0028]
On the other hand, the depth of the tip seal mounting groove is increased so that the amount of protrusion of the tip seal from the tip of the scroll wrap becomes smaller on the side farther from the side where the drive shaft or auxiliary drive shaft is fixed to the fixed scroll or the like. Can be achieved.
[0029]
Further, the third means is that the height of the tip seal provided on the side forming the compression working chamber is closer to the fixed scroll on the side to which the bearing supporting the drive shaft is fixed without changing the tip seal groove depth. The height of the tip seal provided on the side where the compression working chamber is formed is closer to the fixed scroll on the side where the bearing supporting the drive shaft is mounted so as to be movable in the axial direction. It is to be mounted in the mounting groove of the seal.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
A basic configuration of an outer peripheral scroll compressor according to an embodiment of the present invention will be described below with reference to the drawings.
[0031]
FIG. 1 is a longitudinal sectional view showing the overall structure of an outer peripheral scroll compressor according to an embodiment of the present invention.
[0032]
As shown in FIG. 1, the outer periphery driven scroll compressor is of a type that drives two or more drive shafts on the outer peripheral portion of the end plate of the orbiting scroll to drive the orbiting scroll, and is formed in a spiral shape. A fixed scroll 1 having a scroll wrap 1b and a fixed scroll 2 having a scroll wrap 2b formed in the same manner are arranged in parallel, and a scroll wrap 3b formed in the same spiral shape on both sides of the end plate 3a therebetween. And the orbiting scroll 3 having 3c meshes with the respective fixed scrolls.
[0033]
Substantially, the swivel and fixed wraps are configured to mesh with each other while maintaining a non-contact state, and compression working chambers 14 and 15 are formed on both sides of the end plate 3a of the orbiting scroll 3. The compression working chambers 14 and 15 move while reducing their volume from the outer periphery to the center in accordance with the orbiting motion of the orbiting scroll (this situation will be described in more detail in FIG. 5).
[0034]
A communication hole 19 is provided in the vicinity of the central portion of the orbiting scroll end plate for communicating the compression working chamber. Further, the fixed scroll 1 and the fixed scroll 2 are provided with discharge ports 9 and 10 at substantially the center thereof, and heat radiation fins 1d and 2d are provided on the outer surfaces of the fixed scrolls 1 and 2.
[0035]
The end plate 3 a is provided with a plurality of through holes 4 independent of the compression working chambers 14 and 15, and the orbiting scroll 3 can be cooled by flowing air from the outside into the through holes 4.
[0036]
An auxiliary drive shaft 6 having an eccentric portion having the same eccentric amount as the drive shaft 5 having an eccentric portion is arranged on the outer peripheral portion of the end plate of the orbiting scroll 3, and the orbiting scroll 3 has a bearing 11a at the eccentric portion of the drive shaft. And 11b are rotatably engaged.
[0037]
The drive shaft 5 is pivotally supported by a rolling bearing 10a, a part of which is fixed to the fixed scroll 2, and a bearing 12a provided on the fixed scroll 1, and is rotatably supported by the auxiliary drive shaft 6. 2 is rotatably supported by a rolling bearing 10b fixed to 2 and a bearing 12b provided on the fixed scroll 1. Since the rolling bearing 10 fixes the drive shaft 5 and the auxiliary drive shaft 6 to the fixed scroll 2, the rolling bearing 10 is maintained in a state in which axial movement is prevented.
[0038]
On the other hand, the bearing 12 is provided with a pressurizing spring or the like on its side surface so that it can move in the axial direction. Further, balance weights 7 a and 7 b are fixedly disposed on the drive shafts 5 and 6 in order to cancel out the unbalance due to the turning motion of the turning scroll 3.
[0039]
On the other hand, the auxiliary drive shaft 6 located on the opposite side of the drive shaft 5 is also provided with balance weights 8a and 8b fixedly arranged to cancel out the imbalance associated with the orbiting movement of the orbiting scroll 3. Yes.
[0040]
A pulley 16 is provided at the end of the drive shaft 5 via a connecting means for preventing relative slip, for example, a key means, etc., and rotational power is supplied from another installed power source, that is, an electric element (see FIG. 6). Is to be supplied.
[0041]
Further, the drive shaft 5 and the auxiliary drive shaft 6 are connected by a timing belt 17 through toothed pulleys 13a and 13b provided on the respective shafts so as to keep the synchronization of rotation of both drive shafts.
[0042]
The fixed scroll 1 and the fixed scroll 2 are fixed in a state where the parallelism is maintained on the outer peripheral flange surface, but the heights of the two are greatly different. The fixed scroll 1 is configured at a position lower than the wrap height, and the fixed scroll 2 is configured sufficiently higher than the wrap height, and has a casing structure so as to wrap the entire orbiting scroll.
[0043]
For this reason, a space 18 communicating with the atmosphere exists inside the fixed scroll 2. This space 18 is a space necessary for the orbiting scroll 3 to move in the fixed scroll 2 and also a space for flowing cooling air to promote cooling of the compressor. A dust wrap 20 is provided on the outer peripheral portion of the fixed scroll wrap 1 so that the space 18 and the compression working chambers 14 and 15 do not communicate with each other.
[0044]
As shown in FIG. 5, the dust wrap 20 is formed in an annular shape, and a dust seal configured like a tip seal of a wrap tip is provided on the tip of the dust wrap 20. It is fitted in a recessed groove on the surface and has a sealing function while in contact with the end plate surface of the orbiting scroll 3.
[0045]
The fixed scroll 2 disposed on the opposite side is similarly provided with a dust seal 21 and a dust seal at the tip thereof to prevent the outside air of the space 19 and the compression working chamber 15 from communicating with each other. .
[0046]
As described above, the outer peripheral portion of the fixed scroll 2 has a flange portion, and the flange portion is also disposed on the outer peripheral portion of the fixed scroll 1. The fixed scrolls 1 and 2 are connected to each other by bolts or the like at the flange portion.
[0047]
When the two fixed scrolls are combined, the positioning means for matching the relative positions of the two fixed scrolls in the X-Y direction and the rotation direction is assembled with the relative positional relationship between the two fixed scrolls 1 and 2 and the orbiting scroll 3 properly maintained. At the same time as the compression working chambers 14 and 15 suitable for the compression operation are formed, the orbiting scroll 3 can be smoothly orbited.
[0048]
FIG. 2 is a side view of the outer periphery driven scroll compressor of FIG. However, for convenience of explanation, a state in which the cover of the radiation fin is removed is shown. The heat radiating fins 2d are provided in the central portion of the outer surface of the fixed scroll 2 so as to substantially correspond to the positions of the compression working chambers, and are arranged so as to be able to effectively remove the heat generated by the compression.
[0049]
The cooling air is designed to flow from top to bottom in the drawing (details will be described later). Two suction ports 22 and 23 communicating with the compression working chamber 15 are provided on the side surface of the fixed scroll 2.
[0050]
Although not shown in the drawing, the fixed scroll 1 is also provided with a suction port at a similar position so that gas is sucked into the compression working chamber 14. The fixed scroll 2 is made of an aluminum alloy, and a plurality of ribs 24 are arranged on the outer surface to supplement the strength.
[0051]
FIG. 3 is a diagram schematically showing an overview of the orbiting scroll 3, and shows a state in which the fixed scroll wrap 1b meshes with the scroll wrap 3b. The scroll wrap is provided with a scroll wrap 3c formed in the same manner with the end plate 3a interposed therebetween.
[0052]
The lap meshing state shown in FIG. 3 shows a state at a certain rotation angle, and the compression working chamber 14 is formed in a crescent shape by both scroll wraps 1b and 3b as shown. At the same time, a plurality of compression working chambers are formed.
[0053]
A tip seal mounting groove 30 is provided at the tip of the scroll wrap, and a tip seal is provided to prevent gas in the compression working chamber from leaking in the radial direction and flowing into the outer compression working chamber. It has become.
[0054]
The bearing holder holes 25 and 26 are on the outer periphery of the scroll wrap and are configured integrally with the end plate 3a. A plurality of through holes 4 are provided in the end plate 3a of the orbiting scroll, and the respective through holes 4 can join each other inside.
[0055]
FIG. 4 is a bird's-eye view schematically showing the outer periphery driven scroll compressor 40 of FIG. The orbiting scroll 3 is housed in the fixed scrolls 1 and 2 and cannot be seen, but here, for convenience of explanation, only necessary portions are taken out from the inside.
[0056]
A cooling air intake 27 is provided on the upper surface of the fixed scroll 2, and the cooling air flowing in from here flows around the orbiting scroll 3, around the drive shaft 5 and the auxiliary drive shaft 6, and through holes of the orbiting scroll 3. Also flows in 4. Further, a cover (not shown) is provided on the outer side of the heat radiation fins of the fixed scrolls 1 and 2, and a cooling air flow path is also formed around the fins.
[0057]
When the compressor is operated, cooling air flows through these flow paths, and the compressor can be effectively cooled. Support legs 28a and 28b are provided at the lower portion of the compressor, and are thereby fixed to a frame or the like so that the compressor is stably supported.
[0058]
FIG. 5 is a schematic diagram showing the orbiting scroll 3 superimposed on the fixed scroll 2 in order to explain the outline of the internal structure of the compressor. The fixed scroll wrap 2b and the orbiting scroll wrap 3c mesh with each other to form a compression working chamber 15.
[0059]
As shown in FIG. 5, in the scroll compressor, a large number of compression working chambers 15 are formed at the same time, but during the operation of the compressor, the outer peripheral portion has the lowest pressure and the central portion has the highest pressure. .
[0060]
A dust wrap 21 is formed in an annular shape on the fixed scroll side so as to surround the scroll wrap, and a seal member similar to a tip seal is disposed on the top of the dust wrap 21. Is generally blocked.
[0061]
Air that flows in from the cooling air intake 27 provided in the upper part flows into the space 18, and the cooling air flows around the dust lap 21 and around the drive shafts 5, 6 as indicated by arrows in FIG. 5. Then, it flows around the orbiting scroll 3 and flows out from the exhaust port 31 provided in the lower part to the outside of the machine. During this time, heat can be effectively exchanged with the high temperature part, and the scroll member and the like can be kept at a suitable temperature.
[0062]
FIG. 6 is a diagram showing a part of the basic elements and the like of the compressor unit device in which the outer peripheral drive type scroll compressor 40 of FIG. 1 is mounted. The compressor base 43 and the electric element 50 are disposed on the common base 53 via the vibration isolator 44, and the compressor 40 is further disposed on the compressor base 43.
[0063]
The electric element 50 includes a pulley 51 on one side and a fan 54 on the other side. The pulley 51 is provided with a belt 52 connected to the compressor side pulley 16 so that power can be transmitted. Around the electric element 50, flow paths 45 and 55 connected to the fan 54 are disposed in order to obtain an air volume necessary for cooling the compressor 40.
[0064]
The arrows along these flow paths indicate the flow of the cooling air, and the air that flows in by the rotation of the fan 54 includes cooling air that flows around the electric element 50 in parallel therewith. An exhaust duct 56 is provided on the outlet side of the fan 54, and a heat exchanger 46 for cooling the discharge gas from the compressor is provided therein.
[0065]
In the outer peripheral drive type scroll compressor 40, as indicated by the arrow at the top, the cooling air flows from the top to the bottom, and the inside of the compressor flows from the cooling air intake 27, and the cover 41 In addition, there is one that flows through a flow path around the fins constituted by the cover 42.
[0066]
Since the discharge gas has a high temperature and a high pressure, a heat exchanger 46 disposed in the exhaust duct 56 is provided on the front side of the pressure regulating valve 47 so as to be suitably cooled.
[0067]
Normally, the compressor unit device cannot be seen in this manner from the exterior because the entire element described above is surrounded by a sheet metal or the like with makeup. In FIG. 6, for convenience of explanation, a power supply device, an operation control device, a dryer device for adjusting moisture in the compressed air, and the like are also omitted.
[0068]
FIG. 7 is a schematic diagram illustrating a combination state of the orbiting scroll 3 and the pair of fixed scrolls 1 and 2. As shown in FIG. 7, tip seals 1c formed of a composite resin material mainly composed of tetrafluoroethylene resin or polyimide resin at the respective scroll wrap tip portions of the fixed scroll 1, the fixed scroll 2, and the orbiting scroll 3. 2c, 3d, and 3e are respectively provided along the spiral.
[0069]
Each of the tip seals 1c, 2c, 3d, and 3e is arranged on the tip end surface of the scroll wrap. Since the high-pressure gas in the compression operation chamber enters the back surface of each tip seal, the tip is caused by this pressure. The seal protrudes from the mounting groove 30 and is in contact with the mating tooth bottom surface. As a result, suitable sealing performance can be maintained at the tip seal tip.
[0070]
Further, as an example of the present embodiment, when the chip seal is viewed in the length direction along the scroll wrap spiral, the entire chip seal is divided into a plurality. This chip seal does not have to be divided if there is no particular problem in function and performance, but it is preferable to separate the chip seal from the moldability and assemblability of the chip seal, and to escape the thermal expansion during compressor operation. Therefore, the sealing performance and reliability can be improved.
[0071]
Further, as described above, the fixed scrolls 1 and 2 and the orbiting scroll 3 are each made of a material that is light and has good thermal conductivity, as represented by an aluminum alloy or the like. Furthermore, in order to provide an oil-free compressor, it is also possible to apply an aluminum alloy having a small linear expansion coefficient that contains a large amount of silicon.
[0072]
Further, in order to provide an oil-free outer peripheral drive type scroll compressor that is highly reliable for improving the slidability at the time of scroll lap contact or seizure at the time of contact, although not shown, Surface treatment such as anodic oxide film treatment that conforms to the aluminum alloy almost entirely, such as the side surface and end plate surface, and coating with excellent friction and wear characteristics under non-lubricated sliding conditions can also be performed.
[0073]
In FIG. 7, the drive shaft 5 is fixed in an axial relative positional relationship with respect to the fixed scroll 2 by a bearing 10a. Similarly, the relative position of the orbiting scroll 3 is fixed by the bearing 11. The bearing 12a is disposed on the side surface of the bearing via a pressurizing spring or the like so as to be movable with respect to the fixed scroll 1.
[0074]
By the way, the place which pays attention to by this invention is the relative dimension in each scroll wrap front-end | tip part of A, B, C, D enclosed in the circle in the figure. If the thermal expansion amount of the drive shafts 5 to 6 and the thermal expansion amount of the casing of the fixed scroll 2 are the same, during the compression operation, the compression working chambers 14 and 15 have a balanced gas pressure in the compression working chambers above and below the end plate. Since the sum of the thrust forces of the compressed gas that is maintained is substantially equal, the axial movement of the orbiting scroll 3 does not occur.
[0075]
For this reason, the orbiting scroll 3 is not strongly pressed against any of the fixed scrolls 1 and 2, and a large thrust load should not act on the tip surface of the wrap. Therefore, the sliding loss at the tip of the scroll wrap can be kept to a minimum, and the wear amount of the tip seal can be kept small.
[0076]
However, during the compressor operation, when the amount of thermal expansion described above is the same, that is, when the fixed scroll 2 is set to the reference position, the amount of thermal expansion of the drive shafts 5 and 6 and the amount of change in the position of the fixed scroll 1 Are rarely the same. Therefore, when the drive shaft 5 is thermally expanded, the orbiting scroll 3 fixedly locked to the drive shaft 5 moves to the fixed scroll 1 side according to the amount of thermal expansion.
[0077]
As a result, in the known technology, the clearance between the tip of the scroll wrap and the bottom surface of the mating tooth tends to be large at the C and D parts surrounded by circles, and the scroll wrap is opposite at the A and B parts. There is a tendency that the gap between the tip and the bottom surface of the mating tooth becomes smaller. Therefore, in part C and part D, the gas in the compression working chamber 15 is likely to leak to the low pressure side, which may cause a reduction in compressor performance.
[0078]
Further, in part A and part B, the tip seals 3d and 1c may be crushed and a large surface pressure may be applied. In some cases, the tip of the scroll wrap and the tooth bottom may be in direct contact.
[0079]
Furthermore, as a result of these, the pressure levels of the compression working chamber 14 and the compression working chamber 15 become unbalanced, and the thrust force due to the compressed gas acts on the orbiting scroll 3, or the frictional force increases due to the contact on the fixed scroll 1 side. There was a risk that the bearing load would increase and impair the reliability. The present invention is a technique for avoiding these problems, and will be described after the basic operation described below.
[0080]
Next, the operation of the outer periphery driven scroll compressor of FIG. 1 will be described. When electric power is supplied to the electric element 50 of FIG. 6, power is transmitted to the compressor pulley 16 by the belt 52. As a result, the drive shaft 5 shown in FIG. 1 rotates, and at the same time, the auxiliary drive shaft 6 connected by the timing belt 17 rotates.
[0081]
The orbiting scroll 3 engaged with the two drive shafts is caused to orbit with a radius equal to the eccentric amount of the drive shaft in a state where rotation is prevented. As the orbiting scroll 3 moves, air flows into the suction chambers 22a and 23a from the suction ports 22 and 23.
[0082]
The inflowing air is compressed to a predetermined pressure while reducing the volume by the compression working chambers 14 and 15. The high-pressure air is supplied to the outside of the machine from the discharge ports 9 and 10 provided in both the fixed scrolls at a substantially equal pressure by the communication holes 8 provided in the orbiting scroll end plate.
[0083]
The level of the discharge pressure is almost uniquely determined by the opening degree of the pressure adjustment valve 47 shown in FIG. During the compression operation, the compression working chambers 14 and 15 maintain the balance of gas pressure in the compression working chambers above and below the end plate, and in some cases, the pressures are substantially equal at the center of both scrolls. May not be provided.
[0084]
On the other hand, the cooling air of the compressor has a predetermined flow rate secured by the rotation of the fan 54 shown in FIG. 6, the inner and outer surfaces of the fixed scroll and the orbiting scroll are cooled at the same time, and the amount of heat generated by the compression is appropriately removed. be able to.
[0085]
8 is an enlarged view of an embodiment of a portion corresponding to part A in FIG. 7, and FIG. 9 is an enlarged view of an embodiment of a portion corresponding to part D in FIG. FIG. As shown in FIGS. 8 and 9, the distance between the tip surface of one orbiting scroll wrap 3b and the tooth bottom surface of the mating fixed scroll 1 is X1, and the tip surface of the other orbiting scroll wrap 3c and the teeth of the mating fixed scroll 2 are used. When the distance from the bottom is X4, the relationship X1> X4 is maintained.
[0086]
As a specific method for achieving this, first, the fixed scroll 1 and the fixed scroll 2 have the same lap height, and the difference is made in the height dimensions of the orbiting scroll wraps 3b and 3c. it can.
[0087]
As a second method, the fixed scroll wraps 1 and 2 have the same wrap height, and the orbiting scroll wraps 3b and 3c have the same height to fix the engaging portion (fixed position) with the bearing 11. This can be achieved by bringing it to the scroll 2 side.
[0088]
As a third method, this can be achieved by setting the orbiting scroll wraps 3b and 3c to have the same height and setting a difference in the wrap heights of the fixed scroll wraps 1 and 2.
[0089]
By assembling as described above, during the operation of the compressor, X1 and X4 are substantially equal to each other due to thermal expansion of the drive shaft 5 or the like, or at least the relationship of X1> 0 can be maintained. According to the present embodiment, the lap tip clearance during operation is maintained in a suitable state, so that an oil-free scroll compressor having high compressor performance can be provided, and the thermal expansion amount of the drive shaft is increased. It is possible to prevent contact at the front end surface of the scroll wrap.
[0090]
10 is an enlarged view of one embodiment corresponding to the portion B in FIG. 7, and FIG. 11 is an enlarged view of one embodiment corresponding to the portion C in FIG. It is a figure which shows the combination condition with the turning scroll 3 in both scroll wrap front-end | tip parts. Moreover, it is also a figure which shows the combination state under room temperature conditions.
[0091]
As shown in FIGS. 10 and 11, the distance between the tip surface of one fixed scroll wrap 1b and the tooth bottom surface 3a of the other orbiting scroll 3 is X2, and the tip surface of the other fixed scroll wrap 2b and the other orbiting scroll 3 When the distance from the tooth bottom surface 3a is X3, the relationship X2> X3 is maintained.
[0092]
As a specific method for achieving this, first, the wrap heights of the fixed scroll 1 and the fixed scroll 2 are made the same, and the position of the tooth bottom surface of the orbiting scroll 3 is adjusted (for example, with respect to the outer peripheral surface). This can be achieved by providing a difference in the height of the wraps 3b and 3c.
[0093]
As a second method, the fixed scroll wraps 1 and 2 have the same wrap height, and the orbiting scroll wraps 3b and 3c have the same height, and the engaging portion (fixed position) with the bearing 11 is fixed to the fixed scroll 2. This can be achieved by moving to the side. This is substantially the same as the first method, but is when X1 = X2 is satisfied, and only when the wrap height of the orbiting scroll 3 and the wrap height of the fixed scroll are equal. . In practice, the above condition is rarely satisfied, and in many cases X1 ≠ X2.
[0094]
As a third method, this can be achieved by setting the orbiting scroll wraps 3b and 3c to have the same height and setting a difference in the wrap heights of the fixed scroll wraps 1 and 2.
[0095]
In the first method and the second method, a reference surface is partially set in each scroll member, and the scroll wrap meshing surface (tooth bottom surface) is configured to be higher or lower on the basis of the surface. Can be achieved.
[0096]
FIG. 12 is a schematic diagram illustrating a combination state of the orbiting scroll 3 and the pair of fixed scrolls 1 and 2 when the first method and the second method are employed.
[0097]
In FIG. 12, a reference surface 3 </ b> Z provided on the orbiting scroll 3 is a surface on which the tip seal 1 c on the fixed scroll side does not slide on the outer peripheral surface of the orbiting scroll 3. On the other hand, the wrap bottom surface 3Y is configured to be much lower, and for example, a set dimension X2 in FIG. 10 is obtained.
[0098]
Similarly, the reference surface 1Z provided on the fixed scroll 1 is also a surface on which the tip seal 3d provided on the orbiting scroll side does not slide. On the other hand, the lap bottom surface 1Y is configured to be lower, and for example, a set dimension X1 in FIG. 8 is obtained. Setting the steps in this way improves the workability, such as making it easier to check the above dimensions during assembly, and also allows the set dimensions X1 and X2 to be easily set by measuring the step dimensions during maintenance. You can get to know.
[0099]
FIGS. 13 and 14 are partially enlarged views showing other examples of the combined state of the orbiting scroll 3 with the fixed scrolls 1 and 2 at the lap tip, and are also diagrams showing the combined state under a room temperature state.
[0100]
In this example, the set dimensions X1 and X4 are the same as the situation in FIGS. 8 and 9, and a description thereof is omitted here. Hereinafter, differences from the examples of FIGS. 8 and 9 will be described. Here, the dimension of the space provided on the back surface of the chip seal is set to satisfy the relationship of X5 ≧ X6.
[0101]
A specific method for achieving this is to change the tip seal groove depth by making the tip seal groove depth the same, and another method to change the tip seal groove depth by making the tip seal height the same. There is a way.
[0102]
This method is particularly effective when there is a difference between the thermal expansion amount of the tip seal and the thermal expansion amount of the aluminum alloy material that is the scroll material. That is, it is known that the linear expansion coefficient of the aluminum alloy and the above-described chip seal material is as large as about four times.
[0103]
Therefore, when the tip seal is heated together with the wrap, when the tip portion comes into contact with the mating tooth bottom surface, the tip seal is deformed so as to reduce the space on the back surface. At this time, the set dimension X4 tends to increase due to the thermal expansion of the drive shaft 5 on the fixed scroll 2 side, and the escape of the thermal expansion of the tip seal can be shared. Further, if X6 is too large, a large space is always generated during operation, and the compressed gas also causes leakage, so it is necessary to set it to an appropriate size.
[0104]
Further, the set dimension X1 is reduced by the thermal expansion of the drive shaft 5 at the wrap end of the orbiting scroll 3b in FIG. 13, and if X5 is set to a small dimension in advance, the tip seal 3d can escape from the thermal expansion. However, in this example, by taking a large X5, the thermal expansion of the tip seal 3d can be absorbed. An increase in pressure can be prevented.
[0105]
In this example, the sliding surface pressure of the tip seals provided at the wrap tips of the orbiting scroll 3 and the fixed scrolls 1 and 2 is maintained at an appropriate level, so that the wear amount can be kept minute over a long period of time. As a compressor, high performance can be maintained over a long period of time.
[0106]
Further, since the tip seal replacement time can be set long and the number of replacements during a certain period can be reduced, the work cost for tip seal replacement can be reduced.
[0107]
In addition, by applying this example, if the reliability of the compressor and the reliability of the tip seal are set in the same manner as in the case of known technology, a higher discharge pressure (in other words, a higher discharge temperature) can be obtained. A compressor can be provided.
[0108]
【The invention's effect】
According to the present invention, the axial clearance of the compression working chamber can be suitably maintained during the operation of the compressor, so that leakage between the compression working chambers is suppressed, and a high-performance oil-free outer peripheral drive scroll compressor. Can be provided.
[0109]
In addition, since the gas leakage state at the lap tip surface becomes the same, the action of making the pressure distributions of both compression working chambers substantially equal during operation is maintained, and the thrust gas force acting on the end plate of the orbiting scroll is canceled. . As a result, since the thrust force of the bearing is also reduced, the reliability of the bearing can be kept high.
[0110]
Furthermore, since the distance between the tip of the scroll wrap and the bottom surface of the other scroll member is set to a different size in consideration of the amount of thermal expansion of the drive shaft during operation, the surface pressure on the tip seal contact surface is set to an appropriate level. The wear life of the tip seal can be maintained long.
[0111]
Furthermore, contact between so-called scroll base materials between the front end surface of the scroll wrap and the bottom surface of the mating tooth can be avoided, and a highly reliable oil-free outer peripheral drive scroll compressor can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing the overall structure of an oil-free outer peripheral drive scroll compressor according to an embodiment of the present invention.
2 is a side view of the outer periphery driven scroll compressor of FIG. 1. FIG.
3 is a diagram schematically showing an overview of the orbiting scroll in FIG. 1, and is a diagram showing a state in which a fixed scroll rack is engaged. FIG.
4 is a bird's-eye view schematically showing the outer peripheral drive type scroll compressor 40 of FIG. 1, and a schematic three-dimensional view showing a turning scroll taken out from the inside for convenience.
FIG. 5 is a schematic diagram showing an internal structure of the outer periphery driven scroll compressor of FIG. 1;
6 is a diagram showing a basic configuration of a compressor unit device on which the outer peripheral drive type scroll compressor of FIG. 1 is mounted, and is a part of the compressor unit in which a compressor and an electric element are integrated to show a cooling air flow path. FIG.
7 is a cross-sectional view showing a state of engagement of the scroll wrap of FIG. 1; FIG.
8 is an enlarged view of a portion A in FIG.
9 is an enlarged view of a portion D in FIG.
10 is an enlarged view of a portion B in FIG.
11 is an enlarged view of a portion C in FIG.
FIG. 12 is a cross-sectional view showing a state of engagement of scroll wraps in an outer peripheral drive type scroll compressor according to another embodiment of the present invention.
13 is an enlarged view of another example of part A in FIG. 7;
14 is an enlarged view of another example of the D part in FIG. 7;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fixed scroll, 2 ... Fixed scroll, 3 ... Orbiting scroll, 4 ... Cooling hole, 5 ... Main drive shaft, 6 ... Auxiliary drive shaft, 7 ... Balance weight, 8 ... Balance weight, 9 ... Discharge port, 10 ... Discharge Port 11, slewing bearing 12, bearing 13, timing pulley 14, 15, compression working chamber 16, pulley 17, timing belt 18, space 19, communication hole 20, dust trap 22, 23 DESCRIPTION OF SYMBOLS ... Suction hole, 25 ... Slewing bearing bore, 30 ... Mounting groove, 40 ... Peripheral drive type scroll compressor, 43 ... Compressor mount, 44 ... Anti-vibration member, 45 ... Cooling air flow path, 46 ... Heat exchanger , 47: Discharge pressure adjusting valve, 50: Electric element, 51: Pulley, 52 ... Belt, 53 ... Common base, 54 ... Fan, arrow (--->) ... Flow of cooling air

Claims (3)

  A swirl having a scroll wrap and a tooth bottom formed spirally on both sides of the end plate between a pair of fixed scrolls having a scroll wrap and a tooth bottom formed spirally on the inner surface and arranged parallel to each other In a compression working chamber formed by meshing the scroll wraps on both sides of the end plate by rotating the orbiting scroll with a plurality of drive shafts rotatably arranged on the fixed scrolls. In the outer peripheral drive type scroll compressor configured to compress gas, a bearing supporting the drive shaft with which the orbiting scroll is engaged is fixed to one fixed scroll so as not to move in the axial direction, and the other fixed scroll. The drive shaft is arranged so as to be movable in the axial direction, and the compression operation is on the fixed scroll side to which the bearing is fixed. The gap between the front end of the scroll wrap and the tooth bottom surface facing the front end faces the front end of the scroll wrap and the front end of the compression working chamber on the fixed scroll side where the bearing is disposed. An outer periphery-driven scroll compressor characterized in that it is smaller than the gap with the tooth bottom surface.   A swirl having a scroll wrap and a tooth bottom formed spirally on both sides of the end plate between a pair of fixed scrolls having a scroll wrap and a tooth bottom formed spirally on the inner surface and arranged parallel to each other A scroll is disposed, and tip seals are mounted on the front end surfaces of both scroll wraps so as to contact the tooth bottom surfaces facing the front end surfaces, and a plurality of drive shafts are rotatably locked to the two fixed scrolls. In the outer peripheral drive type scroll compressor configured to compress gas in a compression working chamber formed by meshing the scroll wraps on both sides of the end plate by rotating the orbiting scroll, the orbiting scroll is engaged. The bearing that supports the drive shaft is fixed to one fixed scroll so as not to move in the axial direction, and the other fixed scroll is fixed. Is arranged so that the drive shaft can move in the axial direction, and the depth of the tip seal mounting groove provided at the tip of the scroll wrap of the compression working chamber on the fixed scroll side to which the bearing is fixed. The outer peripheral drive type scroll compressor characterized in that the depth is made shallower than the depth of the mounting groove of the tip seal provided on the front end surface of the scroll wrap of the compression working chamber on the fixed scroll side where the bearing is provided.   A swirl having a scroll wrap and a tooth bottom formed spirally on both sides of the end plate between a pair of fixed scrolls having a scroll wrap and a tooth bottom formed spirally on the inner surface and arranged parallel to each other A scroll is disposed, and tip seals are mounted on the front end surfaces of both scroll wraps so as to contact the tooth bottom surfaces facing the front end surfaces, and a plurality of drive shafts are rotatably locked to the two fixed scrolls. In the outer peripheral drive type scroll compressor configured to compress gas in a compression working chamber formed by meshing the scroll wraps on both sides of the end plate by rotating the orbiting scroll, the orbiting scroll is engaged. The bearing that supports the drive shaft is fixed to one fixed scroll so as not to move in the axial direction, and the other fixed scroll is fixed. Is arranged such that the drive shaft is movable in the axial direction, and the height of the tip seal attached to the tip of the scroll wrap of the compression working chamber on the fixed scroll side to which the bearing is fixed, An outer peripheral drive type scroll compressor characterized in that it is higher than the height of a tip seal attached to the end face of the scroll wrap of the compression working chamber on the fixed scroll side where the bearing is disposed.

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