Scroll compressor

Abstract

A scroll compressor includes a fixed scroll having a fixed wrap, and an orbiting scroll having an orbiting wrap engaged with the fixed wrap to define a first compression chamber between an inner surface of the fixed wrap and an outer surface of the orbiting wrap, and to define a second compression chamber between an inner surface of the orbiting wrap and an outer surface of the fixed wrap. A rotation shaft is provided with an eccentric portion at one end thereof to drive the orbiting scroll. A protruding portion protrudes inwardly from an inner end of the fixed wrap, and contacts the orbiting wrap. A distance between a center of the eccentric portion and a tangent line at a contact point between the protruding portion and the orbiting wrap at an end of the first compression chamber is smaller than a radius of the eccentric portion.

Description

CROSS-REFERENCE TO RELATED APPLICATION

shortest distance between the tangent line T and a center of the rotation shaft coupling portion O is smaller than a radius R_H within the rotation shaft coupling portion, so that a shortest distance between the tangent line T at P₃ and a center O of the eccentric bearing 128 is smaller than a radius of the eccentric bearing 128.

Referring to FIGS. 13(a) and 13(b), the inner radius R_H may be defined as an inner radius of the rotation shaft coupling portion when an inner circumferential surface of the rotation shaft coupling portion or an outer circumferential surface of the eccentric bearing is lubricated without a separate bearing, as shown in FIG. 13(a), or may be defined as an outer radius of the bearing when a separate bearing is additionally employed within the rotation shaft coupling portion as shown in FIG. 13(b).

In FIGS. 11 and 12, a point P₅ denotes an inner contact point when the crank angle is 270°, as shown in FIG. 12. A radius of curvature of an outer circumference of the rotation shaft coupling portion may have various values depending on each position between the points P₃ and P₅. Here, the average radius of curvature R_m defined by the following equation may influence the compression ratio of the first compression chamber:

$R_m=\frac{1}{90}{\int }_0^{90}{R}_{\theta }d\theta$
where R_θ is a radius of curvature of the orbiting wrap at the inner contact point of the first compression chamber when the crank angle is θ.

FIG. 14 is a graph showing a relationship between an average radius of curvature and a compression chamber. In general, regarding a rotary compressor, it may have a compression ratio more than 2.3 when being used for both cooling and heating, and more than 2.1 when being used for cooling. Referring to FIG. 14, when the average radius of curvature is less than 10.5, the compression ratio may be more than 2.1. Therefore, if R_m is set to be less than 10.5 mm, the compression ratio may be more than 2.1. Here, R_m may be optionally set to be suitable for the use of the scroll compressor. In the exemplary embodiment, the R_H may have a value of approximately 15 mm. Therefore, the R_m may be set to be smaller than R_H/1.4.

Meanwhile, the point P₅ may not always be limited to when the crank angle is 270°. In view of the operating algorithm of the scroll compressor, a design variable with respect to a radius of curvature up to 270° is low. Accordingly, in order to improve a compression ratio, it is advantageous to change a shape between 270° and 360°, in which the design variable is relatively high.

The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.

As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds, are therefore intended to be embraced by the appended claims.

Claims

1. A scroll compressor comprising:

a fixed scroll having a fixed wrap;

an orbiting scroll having an orbiting wrap, the orbiting wrap configured to define first and second compression chambers at an outer side surface and an inner side surface thereof together with the fixed wrap, the orbiting scroll configured to perform an orbiting motion with respect to the fixed scroll;

a rotation shaft having provided with an eccentric portion at one end portion thereof bearing, the eccentric portion bearing coupled to the orbiting wrap scroll to overlap with each other the orbiting wrap in a lateral direction; and

a driving unit configured to drive the rotation shaft,

wherein a shortest distance between a center o of the eccentric portion bearing and a tangent line at P₃ is smaller than a diameter radius of the eccentric portion bearing, where P₃ is a contact point between the orbiting wrap and the fixed wrap defining one end of the first compression chamber.

2. The scroll compressor of claim 1, wherein the point P₃ is defined as the inner contact point of the first compression chamber upon initiation of discharging of the first compression chamber.

3. The scroll compressor of claim 2, wherein a thickness of the fixed wrap is decreased and then increased as moving from P₃ to P₄, where P₄ is an inner contact point of the first compression chamber 150° before initiating the discharge operation of the first compression chamber.

4. The scroll compressor of claim 1, further comprising:

a rotation shaft coupling portion formed at a central portion of the orbiting scroll, the eccentric portion bearing being coupled to the rotation shaft coupling portion;

a protruding portion protruding from an inner circumferential surface of an inner end of the fixed wrap; and

a recess portion recessed at an outer circumferential surface of the rotation shaft coupling portion,

wherein the outer circumferential surface of the rotation shaft coupling portion at the recess portion contacts the protruding portion of the fixed wrap.

5. A scroll compressor comprising:

a fixed scroll having a fixed wrap;

an orbiting scroll having an orbiting wrap, the orbiting wrap configured to define first and second compression chambers at an outer side surface and an inner side surface thereof together with the fixed wrap, the orbiting scroll configured to perform an orbiting motion with respect to the fixed scroll;

a rotation shaft having an eccentric portion at one end thereof, the eccentric portion coupled to the orbiting wrap to overlap with each other in a lateral direction; and

a driving unit configured to drive the rotation shaft,

wherein the first compression chamber is defined between two contact points P₁ and P₂ generated by the contact between an inner side surface of the fixed wrap and an outer side surface of the orbiting wrap, and

wherein 0°<α<360° 270°<α<345°, where α is an angle defined by two lines which connect a center o of the eccentric portion to the two contact points P₁ and P₂, respectively, and

wherein a distance l between normal vectors at the two contact points P₁ and P₂ is greater than 0.

6. The scroll compressor of claim 5, wherein a distance l between normal lines at the two contact points P₁ and P₂ is greater than 0.

7. The scroll compressor of claim 6 5, wherein the normal lines vectors at the two contact points P₁ and P₂ are different from each other.

8. The scroll compressor of claim 5, wherein a rotation shaft coupling portion is formed at a central portion of the orbiting scroll, the rotation shaft coupling portion having an outer circumferential surface defining a part of the orbiting wrap, an inner side of the rotation shaft coupling portion being coupled with the eccentric portion, wherein 0°<α<360° and l>0 when the first compression chamber is located at the outer circumferential surface of the rotation shaft coupling portion.

9. The scroll compressor of claim 5, wherein 270°<α<345° and l>0.

10. The scroll compressor of claim 5, wherein the rotation shaft comprises:

a shaft portion connected to the driving unit;

a pin portion formed at an end of the shaft portion to be concentric with the shaft portion; and

an eccentric bearing eccentrically provided on the pin portion; and portion,

wherein a rotation shaft coupling portion is formed at a central portion of the orbiting scroll, and

wherein the eccentric bearing is rotatably coupled to the rotation shaft coupling portion.

11. The scroll compressor of claim 10, further comprising:

a protruding portion protruding from an inner circumferential surface of an inner end of the fixed wrap; and

a recess portion recessed at an outer circumferential surface of the rotation shaft coupling portion,

wherein the outer circumferential surface of the rotation shaft coupling portion at the recess portion contacts the protruding portion of the fixed wrap.

12. A scroll compressor comprising:

a fixed scroll having a fixed wrap;

an orbiting scroll having an orbiting wrap, the orbiting wrap configured to define first and second compression chambers at an outer side surface and an inner side surface thereof together with the fixed wrap, the orbiting scroll configured to perform an orbiting motion with respect to the fixed scroll;

a rotation shaft having an eccentric portion at one end thereof, the eccentric portion coupled to the orbiting wrap to overlap with each other in a lateral direction; and

a driving unit configured to drive the rotation shaft,

wherein a thickness of the fixed wrap is decreased and then increased moving in a direction from P₃ to P₄, where P₃ is an inner contact point of the first compression chamber upon initiating a discharge operation of the first compression chamber, and P₄ is an inner contact point of the first compression chamber 150° before initiating the discharge operation of the first compression chamber.

13. The scroll compressor of claim 12, wherein the fixed wrap is thickest at a location between P₃ and an inner end of the fixed wrap.

14. The scroll compressor of claim 12, wherein a distance D_o is increased and then decreased as moving from P₃ to P₄, where D_o is a distance between a center of the eccentric portion and an outer circumferential surface of the orbiting wrap.

15. A scroll compressor comprising:

a fixed scroll having a fixed wrap;

an orbiting scroll having an orbiting wrap, the orbiting wrap configured to define first and second compression chambers at an outer side surface and an inner side surface thereof together with the fixed wrap, the orbiting scroll configured to perform an orbiting motion with respect to the fixed scroll;

a rotation shaft having an eccentric portion at one end thereof, provided with an eccentric bearing, the eccentric portion bearing coupled to the orbiting wrap scroll to overlap with each other the orbiting wrap in a lateral direction;

a driving unit configured to drive the rotation shaft;

a rotation shaft coupling portion formed at a central portion of the orbiting scroll, the eccentric portion bearing being coupled to the rotation shaft coupling portion;

a protruding portion protruding from an inner circumferential surface of an inner end of the fixed wrap; and

a recess portion recessed at an outer circumferential surface of the rotation shaft coupling portion,

wherein the outer circumferential surface of the rotation shaft coupling portion at the recess portion contacts the protruding portion of the fixed wrap.

16. The scroll compressor of claim 15, wherein a shortest distance between a center of the eccentric portion bearing and a tangent line at a contact point between the protruding portion and the orbiting wrap at an end of the first compression chamber is smaller than a diameter radius of the eccentric portion bearing.

17. The scroll compressor of claim 15, wherein the recess portion comprises:

a first increase part defining one side wall of the recess portion; and

a second increase part extending from the first increase part,

wherein a thickness increase rate of the rotation shaft coupling portion at the first increase part is higher than that at the second increase part.

18. The scroll compressor of claim 17, wherein the thickness of the rotation shaft coupling portion is decreased after the second increase part.

19. The scroll compressor of claim 17, wherein another side wall of the recess portion is arcuate.

20. The scroll compressor of claim 15, wherein the protruding portion comprises:

a first part defining one side wall of the protruding portion; and

a second part extending from the first part,

wherein a thickness decrease rate at the first part is higher than that at the second part.