JP2616066B2 - Scroll compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used for air conditioners and refrigerators, and more particularly to an improvement of a high-pressure shell type scroll compressor.

[Conventional technology]

In recent years, the practical application of scroll compressors from medium capacity to small capacity range is remarkable, but in general, the smaller the capacity, the larger the amount of compressed gas leaking from the gap of the compression part, so how to seal this part Is an important point. Even if a contact seal or the like is used, the gap of the compression section is substantially restricted by the processing accuracy. Therefore, in order to obtain a higher sealing performance, an oil seal must be used. The amount of oil required for the oil seal varies depending on the capacity of the compressor, the absolute value of the gap, the operating conditions, and the like, but the smaller the capacity, the more oil is required. When a large amount of oil is required for the oil seal, the refrigerant compressor used for air conditioning and refrigerators generally shares the lubricating oil with the oil seal, so the oil discharged together with the discharge gas is not taken out of the compressor. In addition, it is necessary to reuse the lubricating seal. Therefore, in order to efficiently separate oil in the discharge space and return it to the low pressure side, the inside of the compressor closed vessel (called the shell), which is generally called a high pressure shell type, is set to a high pressure discharge gas atmosphere, and the entire space inside the shell is oil separated. It is more convenient to use it as a space. Further, with this method, a differential pressure lubrication utilizing a differential pressure between a discharge space and a suction space can be used for lubrication. Particularly, in a horizontal compressor in which a compression unit and a motor are horizontal, a positive displacement pump is not required. There are advantages such as simplification of the structure because it is possible.

As a high-pressure shell type scroll compressor, for example, a scroll compressor disclosed in Japanese Patent Publication No. 1-12951 is known.
FIG. 8 shows a sectional side view thereof. In the figure, a fixed scroll (1) is combined with an orbiting scroll (2) to form a compression chamber (11). The frame (6) supports the orbiting scroll (2) and the fixed scroll (1)
Is fixed with bolts. The motor (8) drives the orbiting scroll (2) via the main shaft (3). The frame (6) and the motor (8) are fixed in a shell (9). Here, the gas is sucked from the suction pipe (91), is taken into the compression chamber (11), and has a high pressure from the discharge port (12) and is discharged to the space (94) in the shell (9). 9
2) Discharge from the shell (9). Here, since the spaces (94) and (95) in the shell (9) are equalized, the space (95) has a high pressure, and the oil (93) accumulated at the bottom of the shell is pressurized and the main shaft (3) It is lifted to the end face (3b) by differential pressure from the oil supply hole (33) provided inside, and after lubricating each part, it leaks to the suction side, is taken into the compression chamber (11) with gas, and is partially used for oil seal. After being released, the gas is discharged from the discharge port (12) together with the gas, separated from the gas in the space (94), and returned to the shell bottom by gravity.

[Problems to be solved by the invention]

Since the conventional scroll compressor is configured as described above, the main shaft (3) is supported by the frame (6) disposed on one side of the motor (8), and the back surface of the orbiting scroll (2). Is at low pressure, one end (3a) of the spindle (3) is exposed to the high pressure side, and the other end (3
b) is on the low pressure side, and the spindle (3) has its end face (3b) pressed against the back surface of the orbiting scroll (2) and slides due to the pressure difference, so that there is an extra swinging loss. In particular, the sliding loss becomes larger during high compression ratio operation or high-speed operation by the inverter, and the smaller the capacity of the model, the larger the loss ratio becomes, which cannot be ignored.

On the other hand, a method of canceling the thrust force of the main shaft by equalizing both ends of the main shaft to the high pressure side is conceivable, but in this case, the back pressure of the orbiting scroll is increased, and the oscillating scroll is pressed against the frame side by compression. The thrust force in the opposite direction is larger than the thrust force, causing the orbiting scroll to be pressed against the fixed scroll side and causing the orbiting scroll to become unstable, causing problems such as bearing seizure. Was.

The present invention has been made in order to solve the above problems, and stably lubricates the first and second bearings, and also prevents the upper end of the main shaft from being pressed against the back surface of the orbiting scroll, Further, it is an object of the present invention to obtain a highly efficient and highly reliable scroll compressor capable of operating the orbiting scroll stably under a wide range of operating conditions.

[Means for solving the problem]

In the scroll compressor according to the present invention, a high-pressure atmosphere is set in the shell, and a first motor is driven by a compression chamber formed by a fixed and orbiting scroll.
The second frame is disposed on the side opposite to the compression chamber, the first bearing penetrates the first frame, and the second bearing has one end closed and the other end opened in the second frame. Are provided, and both ends of the main shaft are supported by the first and second bearings, and spaces formed on both end surfaces thereof are communicated with each other to be conducted to the low-pressure portion.

[Action]

In the present invention, since both ends of the main shaft are equalized, no thrust force is generated in the axial direction, and since the thrust is conducted to the low pressure side, both end surfaces are also substantially equalized to a low pressure. as a result,
Since the first bearing end face connected to the orbiting scroll is also at a low pressure, excessive back pressure is not applied, the orbiting scroll can rotate stably, and the differential pressure lubrication to the low pressure side through each bearing portion. it can.

〔Example〕

Hereinafter, an embodiment of the first aspect of the present invention will be described with reference to FIG. FIG. 1 is a side view of the entire cross-section when applied to a horizontal type completely hermetic refrigerant compressor, and the same or corresponding parts as those of the conventional one are denoted by the same reference numerals and description thereof is omitted.
In the drawing, (4) is an Oldham coupling, (5) is a slider, (6A) is a first frame, (7) is a second frame, (9A) is a horizontal shell, and (10) is a suction space. ,
(21) is a thrust bearing, (22) is a swing bearing, (31) is a first space, (32) is a second space, (33A) is a pressure equalizing hole, and (3A)
4) is a slider guide pin, (51) is a slider slit, (61) is a first bearing, (62) is a first oiling hole,
(63) is a circumferential groove, (64) and (65) are communication paths, (71) is a second bearing, (72) is a second oil supply hole, (73) is a circumferential groove,
(74) and (75) are communication paths, (94A), (95A), and (96) are spaces in the shell, and (97) is a sealed terminal.

The fixed scroll (1) is combined with the orbiting scroll (2) to form a compression chamber (11) and is fixed to the first frame (6A). The orbiting scroll (2) is supported on the first frame (6A) via a thrust bearing (21), and via a slider (5) slidably fitted on the orbiting bearing (22). It is connected to the main shaft (3). A slit (51) penetrates through the slider (5), and is slidably fitted in a slider guide pin (34) provided on an end surface of the main shaft in the radial direction, so that the slider (5) can be moved relative to the main shaft (3). The oscillating scroll (2) makes an eccentric rotational movement and the amount of eccentricity can be varied, so that the fixed scroll (1) and the orbiting scroll (2) can be hermetically sealed in the radial direction.

The Oldham coupling (4) is composed of the orbiting scroll (2) and the first
Orbiting scroll (2) between the frame (6A)
The purpose of this is to make the orbital motion while preventing the rotation. The main shaft (3) has a first bearing (61) provided on the first frame (6A) and a first bearing (61) provided on the second frame (7). It is supported by the first frame (6A) and the second frame (7) via the second bearing (71). The first frame (6A) and the second frame (7) are horizontally disposed with a motor (8) interposed therebetween, and their outer peripheral portions are fixed to the shell (9A) with an arc spot or the like. Have been. The motor (8) has its stator fixed on its outer periphery to the shell (9A) by shrink fitting or the like, and its rotor is also fixed to the main shaft (3).

The shell (9A) fills its internal space with the first frame (6A)
And (94A), (95A),
(96) is divided into three parts. The spaces (94A), (95A), and (96) in the shells are connected to communication passages (64), (6) provided on the outer peripheral portions of the first and second frames (6A) and (7).
5), (74) and (75) are electrically connected to each other. Further, a suction pipe (91) is open to the suction space (10) of the fixed scroll (1) via the shell (9A), and the discharge pipe (92) is connected to the space (94A) via the shell (9A). It is open. A sealed terminal (97) is also provided on the shell (9A), and the motor (8) is electrically connected to an external power supply via the sealed terminal (97).

The bottom of the shell (9A) is an oil sump, and the oil (93)
Has stored a certain amount. The first frame (6A) and the second frame (7) are provided with first and second oil supply holes (62) and (72), respectively, and one end is provided with an oil sump oil (93), respectively. Circular grooves (63), (73) open inside and the other ends provided in the planes of the first and second bearings (61), (71)
Connected to each other.

In the scroll compressor configured as described above, the space formed on both end faces of the main shaft (3), that is, the space surrounded by the orbiting scroll (2), the first frame (6A), and the end of the main shaft (3). A first space (31), a second space surrounded by a closed end of the second bearing (71) having one end closed and an open end at the other end of the second frame (7) and an end of the main shaft (3). An equalizing hole (33A) penetrating in the axial direction of the main shaft (3) and electrically connecting the first and second spaces (31) and (32) is provided so as to equalize the pressures of the first and second spaces (32). Furthermore, the first space (3
1) Thrust bearings (2
1) An oil supply groove (21a) is provided radially on the surface.

Next, the operation of such a scroll compressor will be described. The compression principle of the scroll compressor is described in detail, for example, in Japanese Patent Publication No. 1-1951, and will not be described here.

When the motor (8) is energized, the motor (8) generates torque and the main shaft (3) starts rotating. When the main shaft (3) rotates, the slider (5) slides in one direction by the guide pin (34) and the slit (51), and the oscillating scroll (2) comes into contact with the fixed scroll (1) on the spiral side surfaces. The eccentric rotation is performed as described above, and the gas sucked from the suction pipe (91) is guided from the suction space (10) to the compression chamber (11) to compress the gas according to the well-known operation principle of the scroll compressor. The high pressure gas is discharged from the discharge port (12) into the space (94A) in the shell. The discharged high-pressure gas goes out of the shell (9A) from the discharge pipe (92),
The space inside the shell (94A), (95A), and (96)
4) Since the pressure is equalized by (74), all are high pressure spaces. As a result, the oil (93) in the shell oil reservoir is pressurized and supplied to the suction space (10) through the first and second oil supply holes (62) and (72) with a differential pressure.

 Here, each oil supply path will be described in detail below.

First, the oil that has passed through the first oil supply hole (62) flows into the circumferential groove (63) provided in the first bearing (61). Then, it flows in the axial direction through the bearing gap of the first bearing (61), and after lubricating it, flows into the first space (31).
It turns back here and flows in the same axial direction through an oil supply passage (not shown) provided between the slider (5) and the oscillating bearing (22), and after lubricating it, the thrust bearing (21)
Through the oil groove (21a) provided in the thrust bearing (2
1) After lubricating the part, it flows out into the suction space (10). The thrust bearing oil supply groove (21a) has a passage area such that the first space (31) communicates with the suction space (10) and has a sufficient pressure, and is formed, for example, in a radial shape.

The oil that has passed through the second oil supply hole (72) flows into the circumferential groove (73) provided in the second bearing (71), and passes through the bearing gap of the second bearing (71). After flowing in the axial direction and lubricating it, it flows into the second space (32). Further, the oil flows into the first space (31) through the pressure equalizing hole (33A), merges with the oil flowing from the first oil supply hole (62), and thereafter, similarly, the suction space (10). Leaks to

The oil that has flowed into the suction space (10) in this way is taken into the compression chamber (11) together with the gas sucked from the suction pipe (91) and is compressed. At this time, a part of the taken-in oil is used for an oil seal in gaps in various parts of the compression chamber (11). Then, the gas is discharged from the discharge port (12) together with the compressed high-pressure gas, separated from the gas in the space (94A) in the shell, and accumulated at the bottom of the space (94A) in the shell. As described above, the spaces (94A), (95A), and (96) in the shells are equalized with each other, so that the oil flows through the communication passages (65) and (75) so that there is no difference in head. Again, the first and second lubrication holes (6
2) Repeat the suction cycle from (72).

Here, the first space (31) is the slider (5) described above.
Oil supply passage (not shown) and thrust bearing oil supply groove (21
a) and the pressure in the suction space (10) is sufficiently equalized
The second space (32) is composed of the first space (31) and the pressure equalizing hole (33A).
, The first space (31) and the second space (32) are approximately equal to the low pressure of the suction space (10). That is, the high pressure shell interior space (95A) and the low pressure suction space (10) are connected to the first and second bearings (6).
1) and (71) are narrowed by the bearing gaps. Further, since the first and second bearings (61) and (71) have substantially the same diameter as each other, the thrust force due to the high and low pressure differential pressure does not substantially act on the main shaft (3). As a result, the sliding loss at the end face of the main shaft (3) due to the thrust force is eliminated. Further, since the first space (31) has a low pressure, the back pressure applied to the orbiting scroll (2) is substantially all low, and the gas compression thrust force caused by the gas being compressed in the compression chamber (11) is smaller. The orbiting scroll (2) is attached to the thrust bearing (21) regardless of the operating conditions.
Moment (overturning) that causes the orbiting scroll (2) to fall down in the radial direction with respect to the axis by the radial force generated in the orbiting scroll (2) during compression. ), The orbiting scroll (2) can be rotated stably.

Here, regarding the stability of the orbiting scroll (2),
This will be described with reference to FIGS. In Figure 2, the radial gas load F _R is generated due to compression in the orbiting scroll (2), acts the bearing reaction force N _R to the swing bearing (22), these two forces are L ₁ and spaced apart from each other The overturning moment M _R
Occurs. Here the gas thrust load F _T acts on the spiral central portion, moment M inverse moment M _T against _R is M _R =
Thrust bearing reaction force N _T acts on the point A at position L ₂ such that M _T, the orbiting scroll (2) are balanced and the forces and moments are not inclined. On the other hand, when the back pressure of the orbiting scroll (2) increases and the thrust load F _T relatively decreases, assuming that the magnitude of L ₂ is constant as shown in FIG. 3, M _T <M _R , and the orbiting scroll (2) is inclined with the point A as a fulcrum. As a result, the swing bearing (22) is partially hit against the slider (5), causing seizure, or the spiral tip is locally hit, resulting in seizure.

As described above, according to the present invention, the rear surface of the orbiting scroll (2) is always at a low pressure, so that the compressor can be operated with sufficient stability against the overturning moment.

In the above embodiment, the example of the horizontal type compressor has been described, but the compression unit and the motor are arranged vertically.
It may be applied to a so-called vertical type, and furthermore, high and low pressure restricting is performed in the bearing gap, but other restricting means may be used, and if the same effect is obtained, the lubrication path is different. Needless to say, even those included in the present invention are included.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a side view of the entire cross-section when applied to a vertically-installed hermetic refrigerant compressor, and the same or corresponding parts as those in the embodiment of FIG. . In the figure, (9B) is a vertically placed shell, and the oil (93) is accumulated only in the space (96) in the shell. (62
A) and (72A) use the oil (93) in the space (96) in the shell first.
And first and second oil supply pipes leading to the second bearings (61) and (71).

With this configuration, the oil (9
3) is guided as a first oil supply path through a second oil supply pipe (72A) to a second bearing (71) at a substantially high pressure. This oil passes through the bearing gap of the second bearing (71) and passes through the main shaft (3).
To the pressure equalizing hole (33A), which becomes the oil supply passage. At this time, the high-pressure oil is constricted in the bearing gap, and becomes in a substantially low-pressure state. Thereafter, the oil lubricates the swing bearing (22) through the pressure equalizing hole (33A) and is led to the first space (31), and then passes through the radial oil groove of the thrust bearing portion (21). Finally, it is led to the compression chamber (11).

In addition, as the second oil supply path, the oil (9
3) is guided to the first bearing (61) through the first oil supply pipe (62A) at a substantially high pressure. This oil is the first bearing (61)
And is led to the first space (31) through the bearing gap. At this time, the high-pressure oil is constricted in the bearing gap, and becomes in a substantially low-pressure state. Thereafter, this oil passes through the thrust bearing portion (21) similarly to the oil in the first oil supply path described above, and is finally guided to the compression chamber (11).

In the embodiment shown in FIG. 4, the oil supply passage to the first bearing (22) is provided outside the main shaft (3) by the first oil supply pipe (62A). A hole through which high-pressure oil passes may be provided inside the pressure equalizing hole (33A) separately. Hereinafter, a case where a pressure equalizing hole and a high-pressure passage are formed inside and outside the pipe by press-fitting the pipe into a stepped hole formed in the main shaft (3) will be described with reference to FIGS. In the figure, the main shaft (3) is provided with a stepped hole (3c) penetrating in the axial direction. A curving partition pipe (3A) is press-fitted into the stepped hole (3c) using the step as a stopper. Thereby, two oil supply paths are formed: a pressure equalizing hole (33B) having a circular cross section as an oil supply path and a high-pressure oil passage (62B) having a concentric circular cross section as an oil supply path. The first bearing (6A) of the first frame (6A)
The first part of the main shaft (3) corresponding to the circumferential groove (63) of 1)
And a second horizontal hole (3e) in the main shaft (3) at a portion corresponding to the circumferential groove (73) of the second bearing (71) of the second frame (7). I have.

In FIG. 5, the oil (93) at the bottom of the shell passes through the second oil supply pipe (72A) and is led to the orbital groove (73) of the second bearing (71) at a substantially high pressure. A part of this oil is guided to the pressure equalizing hole (33B) of the main shaft (3) through the bearing gap of the second bearing (71) as a first oil supply path. On the other hand, the remaining oil guided to the circumferential groove (73) of the second bearing (71) is used as a second oil supply path through the second lateral hole (3e) of the main shaft (3) and the high-pressure oil passage (62B). Through the first horizontal hole (3d) of the main shaft (3), it is led to the orbital groove (63) of the first bearing (61) at a substantially high pressure.

〔The invention's effect〕

As described above, according to the present invention, the shell is set in a high-pressure atmosphere, and two frames are arranged with the motor interposed therebetween. Both ends of the main shaft are supported by the bearings provided in the two frames, and one of the bearings is penetrated. Then, one end of the main shaft is connected to the orbiting scroll, one end of the other bearing is closed, and both ends are equalized to the low pressure side, and the differential pressure oil is supplied to the low pressure side through the above bearings. Oil supply, and no large back pressure is applied to the orbiting scroll without applying a thrust force to the main shaft.Thus, regardless of the operating conditions, stable high efficiency operation with little sliding loss is possible and low cost. There is an effect that a highly reliable scroll compressor can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view showing a scroll compressor according to an embodiment of the present invention, FIG. 2 and FIG. 3 are principle diagrams for explaining the stability of the orbiting scroll of FIG. FIG. 4 is a cross-sectional side view showing a scroll compressor according to one embodiment of the invention of claim 4, FIG. 5 is a cross-sectional side view of a scroll compressor according to another embodiment of the invention of FIG. 4, and FIG. FIG. 5 is a sectional side view showing only the main shaft, FIG. 7 is an exploded view of FIG. 6, and FIG. 8 is a sectional side view of a conventional scroll compressor. In the figure, (1) is a fixed scroll, (2) is an orbiting scroll, (3) is a spindle, (6A) is a first frame,
(7) is the second frame, (8) is the motor, (9A) is the shell, (11) is the compressor, (21) is the thrust bearing, (31)
Is the first space, (32) is the second space, (33A) is the pressure equalizing hole, (61) is the first bearing, (62) is the first oil supply hole, (7)
1) is a second bearing, (72) is a second oil supply hole, and (93) is oil in a sump. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tatsuya Sugita 3-18-1, Oka, Shizuoka-shi, Shizuoka Mitsubishi Electric Corporation Shizuoka Works (56) References JP-A-62-253982 (JP, A) Hei 2-301687 (JP, A)

Claims (4)

(57) [Claims] 1. A fixed scroll, an oscillating scroll forming a compression chamber for compressing a working fluid in combination with the fixed scroll, a main shaft transmitting a driving force to the oscillating scroll, and a thrust bearing comprising the oscillating scroll. A frame having a bearing that rotatably supports the main shaft while supporting the main shaft, a motor that drives the orbiting scroll, and a closed type shell that stores these and has oil in an oil reservoir at the bottom thereof, The compression chamber, the frame, the main shaft, and the motor are arranged in the shell, and the oil in the oil reservoir is maintained at a high pressure in the shell by utilizing a pressure difference between a high pressure part and a low pressure part. In a scroll compressor for supplying oil to a bearing, the motor is interposed, and a first frame is arranged on a side of the compression chamber and a second frame is arranged on a side opposite to the compression chamber. A first bearing penetrating the first frame, a second bearing having one end closed and the other end opened in the second frame, respectively, and the first and second bearings are provided by the first and second bearings. Both ends of the main shaft are supported in the radial direction, and the first main frame has a first space formed by the first frame, one end of the main shaft, and the orbiting scroll, and a bearing closed end of the second frame and the first frame. A scroll compressor having a second space formed by the other end of the main shaft, and communicating the first and second spaces to the low-pressure portion. 2. The scroll compressor according to claim 1, wherein the second bearing has substantially the same diameter as the first bearing. 3. A scroll compressor in which a compression chamber, a frame, a main shaft, and a motor are horizontally arranged, wherein one end is opened in the first and second bearings and the other end is opened in oil in the oil reservoir. 3. The scroll compressor according to claim 1, wherein an oil supply passage is provided in each of the first and second frames, and each of the bearings communicates with a low-pressure portion. 4. A scroll compressor which supports an orbiting scroll and in which a compression chamber, a frame, a main shaft and a motor are arranged in a vertical direction, wherein a first space and a second space are provided penetrating in the axial direction of the main shaft. A high-pressure oil passage which communicates with the low-pressure portion through the pressure equalizing hole and guides the oil in the oil reservoir to the first and second bearings in a high-pressure state. 2. The scroll compressor according to 2.