JPH0323390A - Enclosed motor driven scroll compressor - Google Patents

Abstract

PURPOSE:To prevent a rotary shaft and main bearing from making uneven mutual engagement by providing a correction means to give to the rotary shaft a correction force for correcting the inclination of the rotary shaft relative to the main bearing and caused by a gas pressure load applied to the rotary shaft. CONSTITUTION:The center 22 of an eccentric shaft 14a of a rotary shaft 14 having its end engaged with a turning scroll 5 for compressing fluid in cooperation with a fixed scroll(not shown) is located eccentrically from the center 21 of the rotary shaft 14 in the direction R, i.e. in the direction orthogonal to a gas pressure load FG. Thus, a gap 3c is formed between the outer peripheral surface 3b' of a rotor 3b and the inner peripheral surface 3a' of a stator 3a and set such that it is smaller in the direction delayed by about 90 deg. in the rotational direction r from the direction R and larger in the direction advanced by about 90 deg.. Thus, a magnetic attraction acting on the rotor 3b is unbalanced so that a magnetic load FM is generated on the rotor 3b as a whole in the direction of plus theta.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a sealed type compressor in which a compressor section and an electric motor section are housed in a closed container, and the compressor section is driven by the electric motor section. The present invention relates to an electric scroll compressor, and relates to a scroll compressor suitable for use, for example, in refrigeration and air conditioning. [Prior Art] This type of scroll compressor is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-263.
As shown in Publication No. 51, fixed scrolling and
It consists of an orbiting scroll that orbits relative to a fixed scroll, and an electric motor that applies orbiting motion to the orbiting scroll via a crank. When the electric motor is started, the volume of the sealed space formed between the fixed scroll and the orbiting scroll is reduced, so that the gas is sucked, compressed, and discharged.

The electric motor that moves this compressor section, like a general electric motor, has a uniform gap between the rotor and stator all around the circumference to make the magnetic flux density uniform, thereby reducing unbalanced forces in the radial direction. Designed to prevent this from occurring. This is the conventional basic principle when constructing an electric motor. This is because the 11-motor is a machine that obtains rotational force, and it is generally considered that unbalanced force in the radial direction on the rotor is undesirable as it increases the bearing load. Scroll compressor electric motors are also conventionally designed to avoid generating unbalanced forces. The main shaft (crankshaft) that is integrated with the electric motor is supported by two main bearings, and is configured to receive the load from the compressor section in a cantilevered manner. [Problems to be Solved by the Invention] When such a hermetic electric scroll compressor is operated, a load is applied from the compressor section to the rotating shaft, that is, the main shaft (crankshaft) in a cantilevered manner, and the load is Since it acts as a so-called rotational load whose direction changes with the rotation of the rotating shaft, the rotating shaft will perform a so-called scouring motion. Therefore, an uneven contact phenomenon occurs in which the rotating shaft and the bearing touch each other at a relative angle, and as a result, in the case of a sliding bearing, there is a risk of seizure due to an increase in localized surface pressure, resulting in a decrease in the reliability of the bearing. ing. Therefore, it is an object of the present invention to provide a hermetic electric scroll compressor in which the load acts most appropriately when the entire compressor including the electric motor is viewed as one machine, and which is highly reliable. More specifically, the purpose is to provide a scroll compressor in which a biased rotational load does not act on the bearing. c. Means for Solving Problems] The above objects of the present invention are. This is achieved by providing a correction means that applies a correction force in a direction to correct the inclination of the rotating shaft that tends to be inclined due to the gas pressure load generated due to gas compression. As this correction means, magnetic force or centrifugal force is applied as described in each claim. [Function] Since the present invention employs the above-mentioned means, the gas compression action can be performed in the same manner as in the conventional method. Even if a gas pressure load acts on the rotating shaft in a direction that tilts the shaft during gas compression, the correction means acts in the direction to return the tilt, so that uneven contact of the bearing supporting the rotating shaft can be avoided. The bearing load can be reduced. [Examples] Examples of the present invention will be described below with reference to the drawings.

The scroll compressor shown in FIG. 1 has a compressor section 2 and an electric motor section 3 housed in a closed container 1. In the compressor section 2, a fixed scroll 4 and an orbiting scroll 5 are meshed with each other to form a compression chamber (closed space) 9. The fixed scroll 4 consists of a disc-shaped end plate 4a and a wrap 4b standing upright on the end plate 4b and formed into an involute curve or a curve similar to this. I am prepared. The orbiting scroll 5 includes a disc-shaped end plate 5a,
It consists of a wrap 5b that stands upright on this and is formed in the same shape as the wrap of the fixed scroll, and a bearing 5c that is formed on the surface opposite to the wrap of the end plate. The frame 11 forms a bearing part 11a having main bearings 1lb and llc in the center, a rotating shaft (main shaft) 14 is supported by the main bearings, and an eccentric shaft 14a at the tip of the rotating shaft can rotate around the bearing 5c. It is inserted like this. Further, a fixed scroll 4 is fixed to the frame 11 with a plurality of bolts, and the orbiting scroll 5 is engaged with the frame 11 by an Oldham mechanism 12 consisting of an Oldham ring and an Oldham key. , it is designed to rotate without rotating. The main shaft 14 is directly connected to the electric rock section 3 at its lower part.

A suction pipe 17 is connected to the suction port 7 of the fixed scroll 4 through the closed container 1, and the discharge chamber 1a into which the discharge port 10 opens is a passage]. It communicates with the lower chamber 1b via 8a and 18b, and further communicates with a discharge pipe 19 that passes through the closed container 1. An empty area surrounded by the back surface of the orbiting scroll 5 and the frame 11
YII! (hereinafter referred to as back pressure chambers) 20 includes gas force in the thrust direction due to gas pressure in a plurality of compression chambers 9 formed by both orbiting and fixed scrolls (this force tends to push down the orbiting scroll 5). ), a gas at a pressure between the suction pressure (low pressure side pressure) and the discharge pressure acts. This intermediate pressure gas is led from inside the compression chamber 9 to the back pressure chamber 20 through pores (not shown) provided in the end plate 5a of the orbiting scroll 5, and acts on the back surface of the orbiting scroll. The rotating shaft l4 and the eccentric shaft 14a are provided with oil supply holes (not shown) for supplying oil to the respective bearings from the oil supply pipe 14b protruding from the lower end of the rotating shaft 14 to the upper end surface of the eccentric shaft 14a. The pipe 14b is immersed in the lubricating oil reservoir 6 at the bottom of the closed container l. In the scroll compressor having the above structure, the eccentric shaft 14a is rotated by the rotation of the rotating shaft 14 directly connected to the electric motor 3.
As a result of the eccentric rotation, the orbiting scroll 5 performs an orbiting motion via the bearing 5c. Due to this swirling movement, the compression chamber 9 gradually moves to the center and its volume decreases. The low-temperature, low-pressure refrigerant gas enters the suction chamber 8 on the outer periphery of the fixed scroll from the suction pipe 17 through the suction port 7, is compressed to increase its pressure, and is discharged from the central discharge port 10 into the discharge chamber 1a. This high-temperature, high-pressure refrigerant gas flows into the lower chamber 1b through the passages 18a and 18b, and is then discharged from the discharge pipe 19 to the outside. By the way, as shown in detail in FIG. 2, the rotating shaft 14 is
It is pivotally supported by a first main bearing 1lb and a second main bearing 11c. 'On the other hand, a load Fa due to gas pressure is applied from the bearing 5C of the orbiting scroll 5 to the eccentric shaft 14a and further to the main shaft 14. There is generally a small gap between the shaft and the bearing. Therefore, when the gas pressure load Fa acts as shown in FIG. 2, the main shaft 14 tilts and points A, B, and C
A partial hit occurs at the point. Such uneven contact is undesirable because it causes wear and seizure and reduces the durability of the bearing.

Assuming that the centrifugal force of the orbiting scroll is completely canceled by the balance weight and does not act on the first main bearing 1lb and the second main bearing 11c, the gas pressure load F6, the first main bearing load FBI, and the second main bearing The following relational expression holds between bearing load F++z.

From the balance of forces, F■=Fa+F■...■Also, from the balance of moments, Fa・Q,=F■・2■...■■, ■FB from the formula! = (1+Qx/Qz)Fa...■
As is clear from equation (2), a load greater than the gas pressure load FQ is applied to the first main bearing 1lb, resulting in uneven contact. Therefore, in the first embodiment of the present invention, correction means as shown in FIGS. 3 and 4 are applied. FIG. 3 is a cross-sectional view of the electric motor section 3 seen from above, showing the rotating shaft 14, stator 3a,
Rotor 3b is shown.

As shown, the center 22 of the eccentric shaft 14a of the rotating shaft 14 is eccentric in the R direction from the center 21 of the rotating shaft 14, and the gas pressure load Fa acts on the rotor in the 0 direction perpendicular to the R direction. outer peripheral surface 3b' of the stator and inner peripheral surface 3a' of the stator
A gap 3C is provided between the R direction and the rotation direction R (rotation direction viewed from above), and this gap is smaller in a direction delayed by approximately 90' from the R direction (this is referred to as the plus θ direction).
A size relationship is established so that the size becomes larger in the direction (minus 0 direction) advanced by 90". In order to set such a relationship, in this embodiment, the shaft hole center 23 of the rotor 3b is the center of the rotating shaft 14. The rotor 3b is attached to the rotating shaft l4 so as to be slightly eccentric with respect to the rotor 21. By creating a size relationship between the gaps in this way, an imbalance occurs in the magnetic attraction force acting on the rotor, and the magnetic attraction The attraction force is strong in the direction delayed by 111890', that is, in the plus θ direction, when viewed from the rotational direction r from the eccentric direction of the eccentric shaft 14a (i.e., the R direction).On the contrary, it acts weakly in the minus θ direction, and as a result, A magnetic load FM is generated on the rotor 3b in the direction of +0 as a whole.The direction of IIFM rotates with the rotation of the crankshaft (rotating shaft) 14, and always acts in the same direction as the gas pressure load Fa.This state is This is shown in Fig. 4. A magnetic force F. acts in the same direction as the gas pressure load F., and this acts to pull the rotating shaft 14 back in the opposite direction to the inclination caused by the gas pressure load F0. Actually F a Q t
< F M Q , when the crankshaft (rotating shaft) 14
is pulled back. As a result, there is no uneven contact between the shaft and bearing, resulting in a favorable lubrication configuration. The relationship between each load is as follows.

Fmt+Fax=Fa+FM −■ Also, from the balance of moments, Foflx+Fmxmz=FmQs ”・■
In other words, F■=F M Q z−F aho, ・・
・■If F M =Ox / Da) F a. Fss=O, ? ■=(1+sad/fia)Fa...■
becomes. As is clear from Figure 4, since Q, 7m, and QE/QU, it can be seen that F'at in the above formula (■) is smaller than FBI in the formula (■). In other words. By appropriately setting the magnitude of the magnetic attraction force FM, it is possible to eliminate uneven contact between the main shaft 14 and the bearing, and to minimize the load on the bearing. Several other embodiments of the present invention will be described below. Figure 5 (the same figure (opening) is the same figure (a)
(This is an explanatory diagram of the rotating shaft 14 seen from above)
In the embodiment shown in FIG.
4) is slightly eccentric from the center 21 of the main body 14 of the shaft 14, so that the gap 3C between the rotor and the stator becomes uneven in the circumferential direction as described above. There is.

In the embodiment shown in Fig. 6, the magnetic east density generated around the rotor is changed in the circumferential direction so that the magnetic attraction force in the plus θ direction becomes stronger. By providing several grooves 3d on the surface to reduce the magnetic flux density in the negative θ direction, the relatively positive θ
A magnetic attraction force is applied in the direction. In the embodiment shown in Fig. 7, the surface directly outside the rotor in the minus 0 direction is partially made into a surface 3e to reduce the magnetic flux density in the minus 0 direction, so that a relatively large magnetic attraction force is exerted in the plus θ direction. I try to do that. Note that Figures 6 and 7 are views of the electric motor section from above. In the embodiment shown in FIG. 8, there are parts mw1 on which the magnetic force acts separately from the magnetic force acting between the rotor and the stator. The figure (opening) is a view of the figure (a) viewed from below. Rotating axis 1
A non-magnetic disc 30 is attached near the shaft end of the disc 4, a part of the disc in the plus θ direction is cut out, and a permanent magnet 31 is embedded there. Stationary rings 32 made of magnetic material are set facing each other with a gap 6. In this way, the magnetic attraction force acts only in a certain direction of the 5 permanent magnets 31, so the shaft end is drawn in the plus zero direction. As a result, effects similar to those of the embodiments shown in FIGS. 3 to 7 can be obtained.

The embodiment shown in Fig. 9 shows a structure in which uneven contact between the shaft and the bearing is eliminated and the bearing load is reduced by using centrifugal force rather than magnetic force. FIG. 9 (opening) is a view of FIG. 9 (a) viewed from below. A weight 40 is provided on the end face of the motor rotor to apply centrifugal force in the plus O direction. When the centrifugal force Fc of the weight 40 acts in the plus θ direction, the rotating shaft 14 is subjected to a gas pressure load F. Pull it in the same direction as the bearing, eliminate uneven contact with the bearing, and reduce the bearing load by Ii. In the embodiment shown in FIG. 10, the direction of action of the centrifugal force Fc of the sub-balance weight 41, which is originally provided in the R direction to balance the centrifugal force of the orbiting scroll, is slightly shifted from the R direction in the plus θ direction. The mounting position of the secondary balance weight has been shifted. By doing so, the plus θ direction component Fc# of the centrifugal force FC has the same effect as in the embodiment shown in FIG. FIG. 10 is a view of the sub-balance weight 41 viewed from below to illustrate this point.

In the embodiment shown in FIG. 11, the direction of action of the centrifugal force of the main balance weight 42, which was originally provided in the minus R direction to balance the centrifugal force of the orbiting scroll, is changed slightly from the minus R direction by minus θ, that is, the gas pressure load F (, The mounting direction of the main balance weight 42 is shifted so that the direction of action is opposite to the direction of action of the main balance weight 42. By doing so, the centrifugal force component pct of the main balance weight 42 in the minus θ direction is caused by the gas pressure load F ( Since it acts to cancel out the +, both the first main bearing load and the second main bearing load can be reduced.

As in some of the above embodiments, the gas pressure load F is caused by magnetic force or centrifugal force. By applying a force in the direction of correcting the inclination of the crankshaft (main shaft) due to this, uneven contact between the shaft and the bearing can be eliminated, and the loads on the first and second main bearings can be reduced. [Effects of the Invention] As detailed above, according to the present invention, since the correction means is provided, even if the rotating shaft tends to tilt due to the gas pressure load, the correction means cancels out the tilt, and the correction means cancels out the tilt. result,
This prevents uneven contact between the rotating shaft and the main bearing, reduces the load on the main bearing, and improves the durability of the bearing. Moreover, since magnetic attraction force and centrifugal force are used as the correction means, the gas pressure load can be offset at low cost with a simple structure.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view showing the overall configuration of a scroll compressor.
Fig. 2 is a partial cross-sectional view showing the effect of gas pressure load and the state of inclination of the rotating shaft, Fig. 3 is a cross-sectional view of the electric motor section of an embodiment of the present invention viewed from above, and Fig. 4 is the same as that of Fig. 3. FIGS. 5 to 11 are partial sectional views showing other embodiments of the present invention, and FIG. 5(a) is a vertical sectional view of main parts, Figure 5 (opening) is a cross-sectional view of the rotor hole in Figure 5 (A) seen from below, Figures 6 and 7 are bottom views of Figure 8 (A), and Figure 9 (I) is a cross-sectional view of Figure 5 (A) seen from below. ) is a longitudinal sectional view of another example, Figure 9 (mouth) is a view of it from below, Figure 1
Figure 0 is a bottom view of the secondary balance weight part in another example as seen from below, and Figure 11 is a physical diagram of the main balance weight part in another example seen from above. 2... Compression section 3... Electric motor section 3a...
・Stator 3b...Rotor 4...Fixed scroll 5...Orbiting scroll 14...Crankshaft 31...Permanent magnet 32...Magnetic ring
40...Way 1, 41.42...Balance weight (other name) Figure 3 Figure R 3b Figure 2 Figure 4 Figure 5 (A) (mouth) Figure 8 (A) (mouth) ) Figure 6 Figure 7 Figure 9

Claims (1)

[Scope of Claims] 1. A fixed scroll and an orbiting scroll each having a spiral wrap upright on an end plate are arranged in a closed container so that the wraps mesh with each other, and a rotating shaft is supported by a main bearing. An orbiting scroll is engaged with a crank part provided at one end, a rotor of an electric motor is fixed to the other end of a rotating shaft, and the rotating shaft is rotated by the electric motor to rotate the orbiting scroll without rotating relative to the fixed scroll. In a hermetic electric scroll compressor that is configured to compress and discharge gas sucked into a compression chamber between an orbiting scroll and a fixed scroll by causing the scroll to move, the rotary shaft due to the gas pressure load applied to the rotating shaft 1. A hermetic electric scroll compressor, comprising a correction means for applying a correction force to a rotating shaft in a direction to correct the inclination of the compressor with respect to a main bearing. 2. The correction means is such that the radial magnetic force acting between the rotor and stator of the electric motor, viewed in the rotational direction of the rotating shaft,
The magnetic flux density distribution between the rotor and stator of the electric motor is set so that it is larger in the radial direction about 90 degrees behind the eccentric direction of the crank part with respect to the rotating shaft than in the radial direction about 90 degrees ahead. The hermetic electric scroll compressor according to claim 1. 3. The hermetic electric scroll compressor according to claim 2, wherein the magnetic flux distribution is set by relatively eccentrically arranging the rotation center of the rotor of the electric motor and the center of the stator. 4. The hermetic electric scroll compressor according to claim 2, wherein the magnetic flux distribution is set by locally changing a gap between a rotor and a stator of the electric motor. 5. Claim 1, wherein the correction means comprises a disk-shaped rotating body that is attached to a rotating shaft and has a magnet portion in a part thereof, and a stationary magnetic body that surrounds the rotating body with a predetermined gap.
The hermetic electric scroll compressor described. 6. The hermetic electric scroll compressor according to claim 1, wherein the correction means is a weight eccentrically attached to the rotating shaft. 7. The correction means shifts the mounting direction of the main balance weight or sub-balance weight, which is originally attached to the rotating shaft, from the original mounting direction to balance the centrifugal force exerted on the rotating shaft from the crank part. A hermetic electric scroll compressor according to claim 1.