JP2938612B2 - Scroll type compression machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type compression machine suitable for use in, for example, an air compressor for compressing air.

[0002]

2. Description of the Related Art FIG. 3 shows an oilless scroll type air compressor as an example of a conventional scroll type compression machine.

[0003] In the drawings, reference numeral 1 denotes a stepped cylindrical casing. The casing 1 is formed in a disc-shaped bottom 1A located on one side in the axial direction, and protrudes inward from the inner peripheral side of the bottom 1A. Bearing portion 1B, a cylindrical portion 1C as a cylindrical portion extending from the outer peripheral side of the bottom portion 1A toward the other side in the axial direction, and a flange portion 1 integrally formed on the distal end side of the cylindrical portion 1C.
D, a thrust receiving portion 1E is formed on the inner peripheral side of the flange portion 1D so as to slide in contact with the back surface of the later-described orbiting scroll 4 and receive a load in the thrust direction in a radially inward direction. Have been.

[0004] Reference numeral 2 denotes a drive shaft rotatably supported by a bearing portion 1B of the casing 1 via ball bearings 3 and 3, and a tip end of the drive shaft 2 extends into the casing 1 to extend the crank 2A. The axis of the crank 2A is eccentric with respect to the axis of the drive shaft 2 by a predetermined dimension d. An electric motor (not shown) is provided on the base end side of the drive shaft 2 outside the casing 1.
, And is rotationally driven by the electric motor.

[0005] Reference numeral 4 denotes an orbiting scroll which is located in the casing 1 and is rotatably provided on the crank 2A of the drive shaft 2. The orbiting scroll 4 includes a disk-shaped head plate 4A and a disk-shaped head plate 4A. A spiral-shaped wrap portion 4 erected with the center side as the winding start end and the outer peripheral side as the winding end end.
B and a boss 4C provided in the center of the rear surface of the end plate 4A. A crank 2A is mounted in the boss 4C via a turning bearing 5 composed of a roller bearing. Further, a thrust gap δ is provided between the tip side (tooth tip) of the wrap portion 4B and a head plate 8A of the fixed scroll 8 described later.
Is defined.

Here, the end plate 4A of the orbiting scroll 4
Key grooves (not shown) are formed at predetermined intervals in the circumferential direction on the outer peripheral side of the rear surface of the vehicle, and an Oldham coupling (not shown) as a rotation preventing mechanism is provided in each of the key grooves. When the drive shaft 2 is driven to rotate, the orbiting scroll 4 is provided with a circular motion having a turning radius of the dimension d by the crank 2A, and rotation is prevented by the Oldham coupling. And keep turning (orbiting).

Reference numeral 6 denotes an annular support plate fixedly provided on the other axial side of the casing 1. The support plate 6 includes an annular plate 6A made of cast iron or the like, and an inner peripheral side of the annular plate 6A. An inner cylindrical portion 6B, which is erected toward the one side in the axial direction, and has a fixed scroll 8 integrally formed on the distal end side, and an outer cylindrical portion, which extends from the outer peripheral side of the annular plate 6A toward one side in the axial direction. 6C, and an outer flange 6C is integrally formed with a mounting flange 7 which is mounted on the distal end side of the outer cylindrical portion 6C by abutting against the flange 1D of the casing 1. The mounting flange 7
A thrust receiving portion 7 </ b> A which slides on the orbiting scroll 4 to receive a load in the thrust direction is formed on the inner peripheral side of the thrust scroll 7.

Reference numeral 8 denotes a fixed scroll which is located on the center side of the support plate 6 and is provided on the inner cylindrical portion 6B of the support plate 6 so as to face the orbiting scroll 4.
Is a mirror plate 8A disposed at the center such that the center coincides with the axis of the drive shaft 2, and a spiral wrap portion 8B erected from the mirror plate 8A in the same manner as the wrap portion 4B of the orbiting scroll 4. A thrust gap δ is defined between the tip of the wrap portion 8B and the end plate 4A of the orbiting scroll 4.

Reference numerals 9, 9,... Denote a plurality of compression chambers defined between the wrap portion 4B of the orbiting scroll 4 and the wrap portion 8B of the fixed scroll 8. Each of the compression chambers 9 is a wrap of the fixed scroll 8. With the wrap portion 4B of the orbiting scroll 4 overlapped with the portion 8B by being shifted by a predetermined angle, the orbiting scroll 4 is formed so as to be sequentially reduced while making the orbital motion.

Reference numeral 10 denotes a suction port formed in the outer cylindrical portion 6C of the support plate 6, reference numeral 11 denotes a discharge port formed in the end plate 8A of the fixed scroll 8, and the suction port 10 is formed on the outermost peripheral side (minimum). The discharge port 11 communicates with the compression chamber 9 on the most central side (highest pressure side). Reference numeral 12 denotes a counter weight fixed to the drive shaft 2, and the counter weight 12 balances the rotation of the drive shaft 2.

The scroll air compressor according to the prior art has the above-described structure. When the drive shaft 2 is driven to rotate by an electric motor, this rotation is transmitted from the crank 2A to the orbiting scroll 4 via the orbiting bearing 5. The orbiting scroll 4 orbits around the axis of the drive shaft 2 with an orbital radius of dimension d. The compression chambers 9, 9,... Defined between the wrap portions 4B, 8B by this swirling motion are continuously reduced, and the air sucked from the suction port 10 is sequentially compressed in the compression chambers 9. Then, the compressed air is discharged from the discharge port 11 to an external air tank or the like to perform a compression action.

[0012]

In the above-mentioned prior art, each compression plate is secured by securing an appropriate thrust gap δ between each end plate 4A, 8A and the tooth tip of each wrap portion 4B, 8B. The space between the chambers 9 is sealed to prevent the compressed air from leaking. However, during the compression operation, compression heat corresponding to the discharge pressure is generated in each compression chamber 9, and this compression heat is transmitted to the orbiting scroll 4 and the fixed scroll 8, and the thermal expansion of each of the scrolls 4, 8 due to the temperature rise thereof Or thrust gap δ is reduced due to thermal deformation due to temperature non-uniformity or fluttering of the orbiting scroll 4 under the condition where the pressure at the start of operation is unstable. There is a problem that occurs.

Therefore, in order to solve the above-mentioned problem, a tip seal made of a material having lubricity such as Teflon is provided at the tip of each wrap portion 4B, 8B, and the tip seal is brought into contact with the end plates 4A, 8A. Is known to seal the space between the compression chambers 9 in this case, but in this case, the tip seal wears with the operation of the compressor, so that not only the sealing performance is unstable, but also , Discharge port 11
There is a problem that abrasion powder of the tip seal is mixed into the compressed air discharged from the nozzle, and clean compressed air cannot be obtained. Also, if the thrust gap δ is set large in advance in anticipation of the thermal expansion during rated operation, it takes a long time for each of the wrap portions 4B and 8B to thermally expand and reach an appropriate thrust gap δ. And the compression efficiency and the like are greatly reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and the thrust gap can be automatically adjusted by displacing the end plate of the fixed scroll in the axial direction using the pressure in the compression chamber. An object of the present invention is to provide a scroll-type compression machine capable of reducing a gap as much as possible.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cylindrical casing,
Is rotatably supported at one end of the cylindrical portion, and the distal end is
A drive shaft extending into the shing and serving as a crank;
So that it can rotate around the drive shaft crank
Spiral with a spiral wrap on the head plate
Rotating scroll and fixed to the other end of the cylindrical portion of the casing
Annular support plate, and the pivoting swivel at the center side of the support plate.
It is provided so as to face the crawl and has a spiral shape on the end plate
Fixed scroll on which the wrap portion is erected, and the fixed scroll
The wrap portion of the orbiting scroll with respect to the wrap portion of the roll
The orbiting scroll performs the orbiting motion in the state where
A plurality of compression chambers formed so as to sequentially reduce
The present invention is applied to a scroll-type compression machine having: Soshi
The feature of the configuration adopted by the invention of claim 1 is that the support plate is
The pressure of each compression chamber acting on the end plate of the fixed scroll
Deformable and is axially Te, the thickness of the support plate, the pressure of each compression chamber acts on the end plate of the fixed scroll those
And <br/> displacement amount to the axial direction of the support plate when displaced in the axial direction, so that the displacement amount and is substantially equal when the lap portion of the fixed scroll is displaced in the axial direction by thermal expansion I have set it.

[0016]

With the above construction, when the end plate of the fixed scroll is urged by the pressure in the compression chamber, the support plate is moved to the fixed scroll.
Axial direction due to the pressure of each compression chamber acting on the roll head
Deform to. At this time, the support plate is deformed in the axial direction by a displacement substantially equal to the displacement when the wrap portion of the fixed scroll is displaced in the axial direction due to thermal expansion, and compensates for the displacement of the end plate in the axial direction.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the prior art shown in FIG. 3 described above are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 21 denotes a support plate according to the present embodiment, which is fixed to the other side in the axial direction of the casing 1. The support plate 21 is made of cast iron or the like in substantially the same manner as the support plate 6 described in the prior art. An annular plate 21A formed in an annular shape,
An inner cylindrical portion 21B, which is erected from the inner peripheral side of 1A toward one axial side and has a fixed scroll 23 which will be described later integrally formed at the distal end side, and one axial side from the outer peripheral side of the annular plate 21A. And an outer cylindrical portion 21C extending therefrom. A mounting flange 22 having a thrust receiving portion 22A is integrally formed at the distal end of the outer cylindrical portion 21C. The thickness dimension h is set by the following equation (2).

Reference numeral 23 denotes a fixed scroll integrally formed on the inner cylindrical portion 21B of the support plate 21 so as to face the orbiting scroll 4, and the fixed scroll 23 is a mirror plate similar to the fixed scroll 8 described in the prior art. 23A and a wrap portion 23B.

Here, there is a correlation between the discharge pressure at the time of the compression action and the temperature rise of the wrap portion 23B of the fixed scroll 23 due to the compression heat, and when the load due to the pressure in each compression chamber 9 acts on the end plate 23A, FIG. 2, the annular plate 21A of the support plate 21 bends to the other side in the axial direction together with the end plate 23A of the fixed scroll 23 in response to this load, so that the thrust acting on the end plate 23A by the pressure of each compression chamber 9 is indicated. The load in the direction is F, the thickness of the annular plate 21A is h,
If the outer diameter of 1A is D, the outer diameter of the end plate 23A is D1, and the longitudinal elastic modulus of the annular plate 21A is E, the displacement W when the end plate 23A is displaced to the other side in the axial direction is:

[0021]

(Equation 1) However, K is obtained as a coefficient obtained from D and D1.

Therefore, for example, the load F in the thrust direction is set to 2
00 kgf, the outer diameter D of the annular plate 21A is 300 mm,
The outer diameter D1 of the end plate 23A is 150 mm,
If the axial displacement amount W1 due to the thermal expansion of B is 30 μm, the coefficient K is 0.03, and these values are substituted into the above equation (1),

[0023]

(Equation 2) However, E: 1.5554 × 10 ⁶ kgf / cm ² , the thickness h of the annular plate 21A can be set to 6.6 mm, and the displacement amount W of the mirror plate 23A to the other side in the axial direction can be set.
And the amount of displacement W1 to one side in the axial direction due to the thermal expansion of the wrap portion 23B can be made substantially equal.

The scroll air compressor according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

However, according to this embodiment, the thickness h of the annular plate 21A of the support plate 21 is changed to the other axial side by the load F in the thrust direction due to the pressure in each compression chamber 9. Since the displacement amount W at the time and the displacement amount W1 when the wrap portion 23B is displaced to one side in the axial direction due to thermal expansion are set to be substantially equal to each other, the displacement amount W1 is set by the above equation (2). The annular plate 21A of the support plate 21 is flexed in the axial direction by the generated load F in the thrust direction, and the end plate 23A of the fixed scroll 23 can be displaced to the other side in the axial direction by the displacement amount W. Can be reliably separated from the end plate 4A.

As a result, the wrap portion 23B
Even if the thermal expansion of one side in the axial direction by the amount of displacement W1, the amount of displacement W1 due to this thermal expansion can be effectively canceled out by the amount of displacement W of the end plate 23A, and the end plate of the wrap portion 23B and the orbiting scroll 4 4A can be kept substantially constant, so that the thrust gap δ can be set small, and the lap portions 4B, 2B
It is possible to reliably prevent the occurrence of the galling phenomenon in 3B, and to greatly improve the start-up performance, the compression efficiency, and the like. Further, the thrust gap δ can be automatically made uniform only by setting the thickness h of the annular plate 21A of the support plate 21, so that the above-mentioned special parts such as the tip seal are not required, and the casing 1 and the orbiting scroll are not required. The reliability and life can be improved at low cost without changing the design such as 4.

In the above-described embodiment, the mounting flange 22 is integrally formed on the distal end side of the outer cylindrical portion 21C of the support plate 21, but instead, the outer cylindrical portion 21C and the mounting flange 22 are connected to each other. They may be formed separately and integrated by using a fixing means such as welding or bonding.

Further, in the above-described embodiment, an oilless scroll type air compressor has been described as an example of the scroll type compression machine. However, the present invention is not limited to this, and for example, Japanese Patent Application Laid-Open No. HEI 2-112690, As disclosed in JP-A-2-248675, a sealing member is provided between the orbiting scroll and the fixed scroll, and lubricating oil is supplied between the orbiting scroll and the thrust receiving portion of the casing and between the orbiting scroll and the thrust receiving portion of the fixed scroll. It can be used also in a scroll type compression machine of a type which supplies and does not supply lubricating oil between each wrap portion tooth tip and the end plate tooth bottom.

Further, the scroll type compression machine of the present invention can be widely applied to compression of refrigerant such as Freon gas and industrial gas such as nitrogen gas as compressed gas.

[0030]

As described in detail above, according to the present invention, the support
Pressure of each compression chamber acting on the end plate of fixed scroll with holding plate
And the thickness of the support plate can be
The pressure of the compression chamber which acts on the end plate of the fixed scroll to the axial direction of the support plate when displaced in the axial direction
And the amount of displacement when the wrap portion of the fixed scroll is displaced in the axial direction by thermal expansion is set to be substantially equal, so when the end plate of the fixed scroll is urged by the pressure in the compression chamber, Support plate is fixed scroll
Axial deformation due to the pressure of each compression chamber acting on the head plate
I do. At this time, the support plate is deformed in the axial direction by a displacement amount substantially equal to the displacement amount when the wrap portion of the fixed scroll is displaced in the axial direction due to thermal expansion, thereby compensating for the displacement of the end plate in the axial direction. As a result, the amount of displacement when the lap portion is displaced in the axial direction due to thermal expansion can be effectively canceled by the amount of displacement when the head plate is displaced in the axial direction due to the pressure in each compression chamber. The thrust gap between the end plate and the end plate is kept substantially constant, the occurrence of galling in the lap portion is reliably prevented, and the start-up performance, compression efficiency and the like can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view showing a main part of a scroll type air compressor according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing axial displacement of a support plate and a fixed scroll.

FIG. 3 is a longitudinal sectional view of a scroll-type air compressor according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 1C Cylindrical part (cylindrical part) 2 Drive shaft 2A Crank 4 Orbiting scroll 4A End plate 4B Lap part 9 Compression chamber 21 Support plate 21A Annular plate 23 Fixed scroll 23A End plate 23B Lap part

Claims (1)

(57) [Claims] 1. A cylindrical casing, a drive shaft rotatably supported at one end of a cylindrical portion of the casing and having a distal end extending into the casing to serve as a crank, and a drive shaft located in the casing. A revolving scroll provided rotatably on the crank of the drive shaft and having a spiral wrap portion erected on the end plate; an annular support plate fixed to the other end of the cylindrical portion of the casing; A fixed scroll provided on the center side of the plate so as to face the orbiting scroll, and a spiral wrap portion is erected on the end plate, and the wrap portion of the orbiting scroll overlapped the wrap portion of the fixed scroll. state, sequentially in the scroll type compressor machine comprising a plurality of compression chambers formed so as to reduce, of the support plate is fixed scroll mirror while orbiting scroll to orbiting motion Each compression chamber acting on the plate
And deformable in the axial direction by the pressure of, the thickness of the support plate, acting on the end plate of the fixed scroll
Wherein the amount of displacement of the said axial direction of the support plate, the displacement amount and is substantially equal when the lap portion of the fixed scroll is displaced in the axial direction by thermal expansion when displaced in the axial direction by the pressure of the compression chamber to A scroll-type compression machine characterized in that it is set to be: