ROTARY COMPRESSOR BACKGROUND OF THE INVENTION

Field of the Invention

[0001]
The present invention relates to a rotary compressor, and more particularly, to a rotary compressor having a plurality of cylinders and partition plates arranged between the cylinders.

Description of the Related Art

[0002]
A rotary compressor has a hermetic container (hereinafter called the "shell") and a driving unit laid out in the shell (hereinafter called the "motor") and a compression unit driven by the motor, in which a refrigerant supplied by way of a suction pipe is cooled in the compression unit and is discharged outside of the shell by way of a discharge pipe. And it is required to achieve larger capacity and cost reduction.

[0003]
The compression unit of a rotary compressor comprising a single cylinder has an annular cylinder, an annular rotary piston that is laid out in an inner circumferential area of the cylinder and rotates eccentrically, a vane that is laid out in a vane groove formed on the cylinder and can advance or retract in the direction of the central axis of the cylinder, a spring for pushing the vane toward the central axis of the cylinder, a crankshaft in which an eccentric core unit is formed in order to make the rotary piston rotate eccentrically, and a pair of frame bodies that rotatably support the crankshaft and block both end faces of the cylinder.

Hence, the space formed by the inner circumferential surface of the cylinder, the outer circumferential surface of the rotary piston, and the pair of frame bodies is divided into a pair of spaces (hereinafter called the "compression chambers") where the volume of each of the spaces is increased or decreased by the eccentrically rotating vane. Namely, a refrigerant absorbed in a phase where the volume increases gradually has a mechanism by which the refrigerant is compressed in a phase where the volume decreases gradually.

[0004]
Also, the compression unit of a rotary compressor comprising two cylinders is equivalent to two layers (two stages) of the configuration layout (which is the same as that of the compression mechanism unit) of the rotary compressor comprising the single cylinder in which the vane grooves of the two layers are laid out in a phase that is 180° opposite to each other, and a "partition plate" is provided between the two cylinders in place of a frame body. Namely, the crankshaft has a pair of eccentric units that are formed in directions that are 180° opposite to each other, and at the same time that the crankshaft penetrates the central through-hole formed on the partition plate, the crankshaft is rotatably supported by a pair of frame bodies.

At this time, the inner diameter of the central through-hole is roughly equal to the sum of the amounts of eccentricity of the eccentric core units of the pair of crankshafts (to put it accurately, the inner diameter is slightly greater than the sum).

[0005]
It should be noted that the compression mechanism unit of a rotary compressor comprising three or more cylinders is equivalent to three layers (three stages) or more of the compression mechanism unit of the rotary compressor comprising the. single cylinder in which the vane grooves of the two layers are laid out in a phase such that the vane grooves will not overlap when viewed in the direction of the central axis of the cylinder. At this time, a partition plate is provided between the cylinders in place of a frame body.

Also, the crankshaft has three or more eccentric core units that are formed in a phase in which they do not overlap when viewed in the direction of the central axis, being rotatably supported by a pair of frame bodies that are laid out at the ends (above the uppermost layer and below the lowermost layer), and penetrates the central through-hole formed on the partition plate.

And a refrigerant that has been compressed in one cylinder is supplied to the other cylinders one by one, thereby being further compressed, and compression in two or more stages is performed.

At this time, the inner diameter of the central through-hole is roughly equivalent to the inner diameter of an imaginary circle that passes through the point that is farthest from the axial core of the three or more eccentric core units of the crankshaft (to put it accurately, the inner diameter of the central through-hole is slightly greater than the diameter of the imaginary circle).

[0006]
In general, methods for increasing the maximum volume of the compression chamber of a rotary compressor having two or more cylinders include (i) a method in which the height of the cylinder (length in the axial direction) is increased, (ii) a method in which the inner diameter of the cylinder is increased (the cylinder is enlarged in the radial direction), and (iii) a method in which the amount of eccentricity of the crankshaft is increased.

When employing method (i) or (ii), the compressor becomes larger and involves a greater cost. For this reason, method (iii) is normally employed in order to eliminate the cost increase resulting from the increase in size.

However, since the inner diameter of the central through-hole that is formed on the partition plate increases with an increase in the amount of eccentricity of the eccentric core unit of the crankshaft, in the case of using method (iii), there arose a problem such that the compression chambers of adjacent cylinders communicate with each other, thereby creating a "leakage flow" and resulting in a worse compression efficiency.

It should be noted that a method may be employed in method (iii) by which the wall thickness (thickness in the diametrical direction; 1/2 of the difference between the outer and inner diameters) of the rotary piston is increased sufficiently for the purpose of preventing the creation of the leakage flow, but in order to increase the amount of eccentricity, there is the need to increase the inner diameter of the cylinder. Then, in order to ensure that there will be an adequate difference between the outer and inner diameters of the cylinder (this difference is equal to the wall thickness) with a view to providing a secure amount of advancement and retraction of the vane as well as a secure strength of the cylinder, there arises the need to increase the outer diameter of the cylinder, thereby requiring a larger compression mechanism unit (shell) and consequently entailing a higher cost.

[0007]
In a rotary compressor comprising two cylinders, a partition plate is disclosed that butts two semi-circular members (hereinafter called "divided partition pieces"). Namely, a semi-circular notch is formed at the center of the linear (planar) edge (hereinafter called the "division plane") of the divided partition piece, thereby ensuring that the axial portion between the eccentric core units of the crankshaft penetrates through the central through-hole that is formed by the notch when the divided partition pieces are butted together.

Namely, there is no need for the eccentric core units of the crankshaft to penetrate through the central through-hole as a result of assembling the axial portion between the eccentric core units of the crankshaft so that the portion is sandwiched between the divided partition pieces, and so the inner diameter of the central through-hole (which is a value obtained by multiplying the radius of curvature of the notch by two) can be reduced to a value that is roughly equal to the outer diameter of the axial portion of the crankshaft (for example, see Patent Literature 1).

[0008]
[Patent literature 1] Japanese examined patent publication for 54-121405 Japanese and unexamined publication No. 54-121405 (page 2; figure 2)

SUMMARY OF THE INVENTION

[0009]
However, the invention disclosed in Patent Literature 1 had the following problem.

The partition plate disclosed in Patent Literature 1 is tightened by bolts (hereinafter called the "abutting bolts") in the circumferential direction in two places facing each other on the outer circumferences of the divided partition pieces so that the division planes will press against each other intermediated by sealing material between the division planes, and at the same time the top and bottom planes of the divided partition piece are compressed by a pair of cylinders. Such compression is realized by fastening of a plurality of bolts (hereinafter called the "assembling bolts") for integrating the partition plate, the pair of cylinders, and a pair of frame bodies.

For this reason, when assembling the divided partition pieces, each of the divided partition pieces was deformed in an unbalanced way by the fastening force of the abutting bolts or by uneven fastening force of a plurality of assembling bolts, thereby creating a level difference in the division planes of the divided partition pieces.

[0010]
Accordingly, there occurred a problem in which a leakage flow was formed between the rotary piston and partition plate (the divided partition pieces abutting with each other) and the efficiency of the compressor was deteriorated by leakage loss.

It should be noted that if the plate thicknesses of the divided partition pieces are increased in order to suppress the deformation caused by the fastening force of the abutting bolts with a view to suppressing the formation of the leakage flow, then the length of the axial portion between the eccentric core units of the crankshaft increases, with the result that the distance between the bearings (installed onto the frame bodies) that support the crankshaft increases. If so, it was necessary to make the crankshaft thicker in order to secure the necessary strength of the crankshaft, and there arose a problem in which such need led to a greater diameter in other members with the result that an increase in the weight of the compressor caused the cost to rise.

[0011]
The prevent invention was made in order to solve the above problem, and is intended to provide a rotary compressor that has a partition plate formed by a plurality of divided partition pieces and can suppress the creation of a level difference between the division planes of the divided partition pieces abutting with each other.

[0012]
The prevent invention discloses a rotary compressor comprising: a hermetic container, a driving unit and a compression unit that are laid out in the hermetic container, and a crankshaft that transmits rotation of the driving unit to the compression unit, the compression unit being formed by a pair of compression mechanism units laminated with a partition plate being interposed therebetween, the partition plate being formed by a plurality of divided partition pieces that are divided by division planes in the radial direction, a hole for an assembling bolt being made on each of the divided partition pieces, of the holes for assembling bolts, a pair of holes for assembling bolts facing each other across the division plane are located symmetrical to the division plane when the partition plate is formed by butting the divided partition pieces, and of the assembling bolts, the assembling bolts inserted in the pair of the holes for assembling bolts facing each other across the division plane have nearly the same tightening force.

[0013]
The rotary compressor disclosed according to the prevent invention can cope with large capacity and low cost because its central through-hole can be made smaller due to the formation of the partition plate by means of a plurality of divided partition pieces, and at the same time enables suppression of deterioration in compressor efficiency as caused by leakage loss because the creation of a level difference in division planes is suppressed due to the fact that the holes for assembling bolts are located symmetrically across the division plane and the assembling bolts inserted in the pair of the holes for assembling bolts facing each other across the division plane that are located in the symmetrical positions have nearly the same tightening force.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]
Fig. 1 Cross section of a side view showing the entire parts of the rotary compressor related to Embodiment 1 for carrying out the present invention

Fig. 2 Cross section of a side view showing a part (compression mechanism unit) of the rotary compressor shown in Fig. 1

Fig. 3 Cross section of a plan view showing part (compression mechanism unit) of the rotary compressor shown in Fig. 1

Fig. 4 Plan view showing a part (partition plate) of the rotary compressor shown in Fig. 1

Fig. 5 Plan view showing an example of a variation of a part (partition plate) of the rotary compressor shown in Fig. 1

Description of Embodiments

[0015] [Embodiment 1]
The rotary compressor related to Embodiment 1 in the present invention is explained below by referring to the drawings.

Figs. 1 through 5 illustrate schematically the rotary compressor related to Embodiment 1 in the present invention. Fig. 1 is a cross section of a side view showing the entire parts; Fig. 2 is a cross section of a side view zooming and showing a part (compression mechanism unit);

Fig. 3 is a cross section of a plan view zooming and showing a part (partition plate); Fig. 4 is a plan view showing a part (partition plate), and

Fig. 5 is a plan view showing an example of deformation of a part (partition plate). It should be noted that these drawings are drawn schematically, and so the present invention is not limited to the embodiments illustrated herein.

With reference to Figs. 1 through 4, rotary compressor 100 comprises shell 101 which is a hermetic container, driving unit (hereinafter called "motor") 102 which is a driving source installed inside shell 101, and compression unit 103 which is also installed inside shell 101.

[0016]
(Shell)
Shell 101 consists of upper shell 101a and lower shell 101b. Upper shell 101 a is provided with glass terminal 104 for supplying electric power from outside to motor 102, and discharge pipe 105 for discharging the compressed refrigerant to the outside of shell 101 (compressor 100).

Fixed to lower shell 101b are motor 102, first compression mechanism unit 10a and second compression mechanism unit 10b that make up compression unit 103, and first suction pipe 106a and second suction pipe 106b that introduce the refrigerant to first compression mechanism unit 10a and second compression mechanism unit 10b, respectively. First suction pipe 106a and second suction pipe 106b communicate with suction muffler 107, and inside suction muffler 107 gas-liquid separation for the refrigerant and removal of trash inside the refrigerant are carried out.

It should be noted that in the explanation below, with regard to the identical contents concerning first compression mechanism unit 10a and second compression mechanism unit 10b, descriptions of the words "first" and "second" that modify the names as well as of the suffix codes "a" and "b" may be omitted.

[0017] (Motor)
Motor 102 has stator 102a and rotor 102b, and rotor 102b is mounted to crankshaft 50 (the details of which will be explained separately). The rotational torque generated in motor 102 is transmitted to first compression mechanism unit 10a and second compression mechanism unit 10b by means of crankshaft 50.

[0018]
(Compression unit) Compression unit 103 has first compression mechanism unit 10a and second compression mechanism unit 10b laminated with partition plate 30 being interposed there between. First compression mechanism unit 10a comprises annular first cylinder 11a, annular first rotary piston (hereinafter called "first piston") 12a that is laid out in the inner circumference unit of first cylinder 11 a and rotates eccentrically while abutting with the inner circumferential surface of first cylinder 11a, first vane 14a that is laid out in first vane groove 13a that is formed on first cylinder 11a and can advance or retract in the direction of the central axis of first cylinder 11a, and first spring 15a that presses first vane 14a against the outer circumference of first piston 12a. At this time, the outer circumferential surface of first piston 12a linearly abuts on the inner circumferential surface of first cylinder 11 a, and the point of linear abutment moves as eccentric rotation occurs.

[0019]
Likewise, second compression mechanism unit 10b comprises annular second cylinder 11 b, annular second rotary piston (hereinafter called "second piston") 12b that is laid out in the inner circumference unit of second cylinder 11 b and rotates eccentrically while abutting with the inner circumferential surface of second cylinder 11b, second vane 14b that is laid out in second vane groove 13b that is formed on second cylinder 11b and can advance or retract in the direction of the central axis of second cylinder 11b, and second spring 15b that presses second vane 14b against the outer circumference of second piston 12b. At this time, the outer circumferential surface of second piston 12b linearly abuts on the inner circumferential surface of second cylinder 11 b, and the point of linear abutment moves as eccentric rotation occurs.

[0020]
(Assembly of the compression mechanism unit)
One end face (upper surface) of first cylinder 11 a is covered with a first frame body 20a on which first frame body bolt hole 21 a is made, and the other end face (lower surface) of first cylinder 11a is covered with partition plate 30 on which central through-hole 33 and assembly through-holes 35 and 36 (the details of which will be explained separately) are made.

Also, one end face (lower surface) of second cylinder 11 b is covered with second frame body 20b on which second frame body bolt hole 21b is made, and the other end face (upper surface) of second cylinder 11 b is covered with partition plate 30.

[0021]
And on the first frame body 20a and second frame body 20b, first frame body bolt hole 21a and second frame body bolt hole 21b, respectively, are made for assembling purposes for each of the frame bodies.

Also, first cylinder 11a is provided with first cylinder bolt hole 16a and first cylinder bolt thread 17a for assembly, and second cylinder 11 b is provided with second cylinder bolt hole 16b and second cylinder bolt thread 17b for assembly.

And first assembly short bolt 71 a that penetrates through first frame body bolt hole 21a and engages with first cylinder bolt thread 17a joins the first frame body 20a and first cylinder 11a, and second assembly short bolt 71b that penetrates through second frame body bolt hole 21b and engages with second cylinder bolt thread 17b joins second frame body 20b and second cylinder 11 b.

[0022]
Moreover, first assembly long bolt 72a that penetrates through first frame body bolt hole 21a, first cylinder bolt hole 16a, and assembly through-hole 35 or assembling bolt hole 36, thereby engaging with second cylinder bolt thread 17b, as well as second assembly long bolt 72b that penetrates through second frame body bolt hole 21b, second cylinder bolt hole 16b, and assembly through-hole 35 or assembling bolt hole 36, thereby engaging with first cylinder bolt thread 17a, pull together the first frame body 20a and second frame body 20b, and compress partition plate 30 by way of first cylinder 11 a and second cylinder 11b.

[0023] (Compression chamber) Therefore, first space 40a surrounded by the inner circumferential surface of first cylinder 11a, outer circumferential surface of first piston 12a, lower surface of the first frame body 20a, and upper surface of partition plate 30 is divided into two parts in the circumferential direction by the abutment of the inner circumferential surface of first cylinder 11 a with the outer circumferential surface of first piston 12a (these surfaces roughly linearly abut with each other) as well as by the abutment of first vane 14a with the outer circumferential surface of first piston 12a (these surfaces roughly linearly abut with each other).

Likewise, second space 40b surrounded by the inner circumferential surface of second cylinder 11b, outer circumferential surface of second piston 12b, upper surface of second frame body 20b, and lower surface of partition plate 30 is divided into two parts in the circumferential direction by the abutment of the inner circumferential surface of second cylinder 11 b with the outer circumferential surface of second piston 12b as well as by the.abutment of second vane 14b with the outer circumferential surface of second piston 12b (see Fig. 3).

[0024] (Crankshaft) Crankshaft 50 has first bearing insertion unit 52a, partition plate insertion unit 53, and second bearing insertion unit 52b that are laid out coaxially, and between first bearing insertion unit 52a and partition plate insertion unit 53, first eccentric core unit 51a that is eccentrically disposed toward one direction is formed, and between second bearing insertion unit 52b and partition plate insertion unit 53, second eccentric core unit 51b that is eccentrically disposed toward the other direction is formed.

At this time, first eccentric core unit 51a and second eccentric core unit 51b face each other (the direction of eccentricity differs 180°) and are parallel to the axial core.

Also, the first bearing insertion unit 52a is rotatably supported by first bearing 25a that is provided on the inner circumferential surface of the first frame body 20a, and second bearing insertion unit 52b is rotatably supported by second bearing 25b that is provided on the inner circumferential surface of second frame body 20b, and partition plate insertion unit 53 penetrates through central through-hole 33 that is made at the center of partition plate 30.

[0025]
(Compression of the refrigerant) And because first eccentric core unit 51a penetrates through the inner circumferential area of first piston 12a and second eccentric core unit 51b penetrates through the inner circumferential area of second piston 12b, the rotation of the crankshaft causes first piston 12a and second piston 12b to rotate eccentrically with a 180-degree phase difference between the two pistons (see (a) and (b) of Fig. 3).

For this reason, as a result of the rotation of crankshaft 50, the volume of one of the two spaces divided in first space 40a gradually increases, and the volume of the other space in first space 40a gradually decreases. Namely, the first air inlet (not illustrated) is formed at a position corresponding to the one space, and the first air outlet (not illustrated) is formed at a position corresponding to the other space, and so the refrigerant is drawn in through the first air inlet, and then after being compressed, is discharged through the first air outlet.

[0026]
(Partition plate) In Fig. 4, partition plate 30 is a roughly circular disc on which central through-hole 33 is formed at the center, and on division plane 34 the partition plate is divided into two, i.e. into first divided partition piece 31 and second divided partition piece 32, and division plane 34 is formed along the radial direction (parallel to the direction in which first vane 14a and second vane 14b advance or retract). It should be noted that division plane 34 corresponds to a plane where the first plane formed on first divided partition piece 31 abuts with the second plane formed on second divided partition piece 32, but for the purpose of explanatory convenience, division plane 34 may mean not only the place where the first plane abuts with the second plane, but also each of the first and second planes.

And on first divided partition piece 31, first assembling bolt holes 35a, 35b, 35c and 35d in the axial direction are formed and arranged roughly equiangularly along the outer circumferential surface, and at the center of division plane 34, arc-like first notched area 33a is formed, and on second divided partition piece 32, second assembling bolt holes 36a and 36b in the axial direction are formed along the outer circumferential surface, and at the center of division plane 34, arc-like second notched area 33b is formed.

[0027]
(Level difference) At this time, when partition plate 30 is formed by abutting first divided partition piece 31 with second divided partition piece 32, a pair of 'first assembling bolt hole 35a and second assembling bolt hole 36a" that face each other across division plane 34 are located symmetrical to division plane 34, and likewise, a pair of 'first assembling bolt hole 35d and second assembling bolt hole 36b" that face each other across division plane 34 are located symmetrical to division plane 34.

Moreover, the tightening forces (F35a, F36a) of the assembling bolt inserted into first assembling bolt hole 35a (see Fig. 2) and the assembling bolt inserted into second assembling bolt hole 36a (see Fig. 2) are nearly equal (F35a = F36a).

[0028]
Likewise, the tightening forces (F35d, F36b) of the assembling bolt inserted into first assembling bolt hole 35d (see Fig. 2) and the assembling bolt inserted into second assembling bolt hole 36b (see Fig. 2) are nearly equal (F35d = F36b).

Therefore, since the ranges of first divided partition piece 31 and second divided partition piece 32 that are close to division plane 34 are subjected to similar deformation that is almost symmetrical (compressive deformation in the axial direction), it becomes

possible to suppress the generation of a level difference because the plate thicknesses of first divided partition piece 31 and second divided partition piece 32 on division plane 34 (plate thicknesses after deformation) are nearly the same. Hence, since no leakage flow is formed between first space 40a and second space 40b, deterioration in compressor efficiency as caused by leakage loss can be prevented.

[0029]
Moreover, the surface pressure per unit area (F35/S31) obtained by dividing the sum (F35 = F35a + F35b + F35c + F35d) of the tightening forces (F35a, F35b, F35c and F35d) of the assembling bolts to be inserted into first assembling bolt holes 35a, 35b, 35c and 35d, respectively of first divided partition piece 31 by the abutment area (S31) between first divided partition piece 31 and the end face of cylinder 11 is made to be nearly equal to the surface pressure per unit area (F36/S32) obtained by dividing the sum (F36 = F36a + F36b) of the tightening forces (F36a, F36b) of the assembling bolts to be inserted into second assembling bolt holes 36a, 36b, respectively on second divided partition piece 32 by the area of abutment (S32) between second divided partition piece 32 and the end face of cylinder 11.

Hence, it becomes possible to further suppress the generation of a level difference on division plane 34, and since no leakage flow is formed between first space 40a and second space 40b, deterioration in compressor efficiency as caused by leakage loss can further be prevented.

[0030]
(Abutting bolts) On the outer circumference of first divided partition piece 31 and the outer circumference of second divided partition piece 32, first notched areas 63a, 63b and second notched areas 65a, 65b, respectively, are formed, and on both ends of division plane 34, first flanges 64a, 64b and second flanges 66a, 66b are formed, and on first

flanges 64a, 64b, abutting bolt threads 61a, 61b that are perpendicular to division plane 34 are formed, and likewise on second flanges 66a, 66b, abutting bolt holes 62a, 62b that are perpendicular to division plane 34 are formed.

Therefore, by inserting abutting bolts 60a, 60b into abutting bolt holes 62a, 62b, and making these bolts engage with abutting bolt threads 61 a, 61b, it becomes possible to make first divided partition piece 31 abut with second divided partition piece 32 so that these pieces press against each other on division plane 34. Hence, it is possible to produce abutment so that first divided partition piece 31 and second divided partition piece 32 are located on the same plane before compressing partition plate 30 by means of first cylinder 11 a, etc.

It should be noted that in the above explanation, first flanges 64a, 64b and second flanges 66a, 66b are formed on both ends of division plane 34, but the present invention is not limited thereto, and abutting bolt holes 62a, 62b may be provided with a seat (spot facing) upon which the heads of the abutting bolts abut by omitting the formation of second notched areas 65a, 65b and omitting formation of first notched areas 63a and 63b.

Moreover, in the above explanation, a bolt thread is formed on first divided partition piece 31 and a bolt hole is formed on second divided partition piece 32, but the present invention does not impose any limitations regarding such formation, and a bolt thread and a bolt hole may be formed on first divided partition piece 31, and at the respective positions corresponding thereto on second divided partition piece 32, a bolt hole and a bolt thread may be formed.

[0031]
Partition plate 300 illustrated in Fig. 5 is a variation of partition plate 300 illustrated in Fig. 4, and is formed by first divided partition piece 310 and second divided partition piece 320 that are roughly semicircular. It should be noted that for the purpose of explanatory convenience, any portion that is the same as or equivalent to partition plate 30 is provided with the same code, and a part of the explanations is omitted.
In Fig. 5, first divided partition piece 310 and second divided partition piece 320 on partition plate 300 are roughly semicircular and are roughly symmetrical to division plane 34 which is the symmetry plane.

And on first divided partition piece 310, first assembling bolt holes 35a, 35b, and 35c are formed, and on second divided partition piece 320, second assembling bolt holes 36a, 36b, and 36c are formed. And first assembling bolt hole 35a and second assembling bolt hole 36a are laid out symmetrical to division plane 34, and first assembling bolt hole 35c and second assembling bolt hole 36c are laid out symmetrical to division plane 34.

Moreover, the tightening forces (F35a, F36a) of the assembling bolt inserted into first assembling bolt hole 35a (see Fig. 2) and the assembling bolt inserted into second assembling bolt hole 36a (see Fig. 2) are nearly equal (F35a = F36a), and the tightening forces (F35c, F36c) of the assembling bolt inserted into first assembling bolt hole 35c (see Fig. 2) and the assembling bolt inserted into second assembling bolt hole 36c (see Fig. 2) are nearly equal (F35c = F36c).

[0032]
(Level difference) Therefore, since the ranges of first divided partition piece 310 and second divided partition piece 320 that are close to division plane 34 are subjected to similar deformation that is almost symmetrical (compressive deformation in the axial direction), it becomes possible to suppress the generation of a level difference because the plate thicknesses of first divided partition piece 310 and second divided partition piece 320 on division plane 34 (plate thicknesses after deformation) are nearly the same. Hence, since no leakage flow is formed between first space 40a and second space 40b, deterioration in compressor efficiency as caused by leakage loss can be prevented.
Moreover, the surface pressure per unit area (F35/S31) obtained by dividing the sum (F35 = F35a + F35b + F35c) of the tightening forces (F35a, F35b, and F35c) of the first assembling bolts to be inserted into first assembling bolt holes 35a, 35b, and 35c, respectively on first divided partition piece 310 by the abutment area (S31) between first divided partition piece 31 and the end face of cylinder 11 is set to a value that is nearly equal to the surface pressure per unit area (F36/S32) obtained by dividing the sum (F36 = F36a + F36b + F36c) of the tightening forces (F36a, F36b, F36c) of the second assembling bolts to be inserted into second assembling bolt holes 36a, 36b, and 36c, respectively on second divided partition piece 32 by the abutment area (S32) between second divided partition piece 32 and the end face of cylinder 11, and so it becomes possible to further suppress the generation of the level difference. Hence, since no leakage flow is formed between first space 40a and second space 40b, deterioration in compressor efficiency as caused by leakage loss can further be prevented.

[0033]
(Compression unit) Based on the foregoing, the compression unit in the present invention can be described as follows:
"Having an annular cylinder, an annular rotary piston that is laid out in an inner circumferential area of the cylinder and rotates eccentrically while abutting with the inner circumferential surface of the cylinder, a vane that is laid out in a vane groove formed on the cylinder and can advance or retract in the direction of the central axis of the cylinder, and a spring that presses the vane onto the outer circumference of the rotary piston;
the space surrounded by the frame body covering one end face of the cylinder, the partition plate covering the other end face of the cylinder, the inner circumferential surface of the cylinder, and the outer circumferential surface of the rotary piston is divided by the vane into two compression chambers; the crankshaft has a pair of eccentric units that are formed in directions that are opposite to each other, and at the same time that the crankshaft is rotatably supported by the means of bearings installed in the frame body, the crankshaft penetrates the central through-hole formed on the partition plate; and
the eccentric core unit of the crankshaft penetrates through each of the inner circumferential areas of the rotary piston, and makes the rotary piston rotate eccentrically by means of rotation of the crankshaft, thereby increasing the volume of one of the compression chambers, and at the same time decreases the volume of the other compression chamber."

[0034]
[Other embodiments] The above shows embodiments in which compression unit 103 consists of first compression mechanism unit 10a and second compression mechanism unit 10b, but the present invention does not impose any limitations regarding such embodiments, and compression unit 103 may comprise laminated three or more compression mechanisms in which there are three or more layers.

For example, in the case of a construction of three layers, the compression mechanism at the end (topmost) position is equivalent to, in place of partition plate 30 in first compression mechanism unit 10a, that which abuts with a similar first partition plate, and the compression mechanism at the end (lowermost) position is equivalent to, in place of partition plate 30 in second compression mechanism unit 10b, that which abuts with a similar second partition plate, and the intermediate compression mechanism unit is equivalent to, in place of the first frame body 20a and partition plate 30 in first compression mechanism unit 10a (or in place of second frame body 20b and partition plate 30 in second compression mechanism unit 10b), that which abuts with the first partition plate and second partition plate. And the crankshaft has eccentric core units in three places, each of which involving eccentricity in a different direction.

Also, in the case of a construction of four or more layers, the intermediate compression mechanism unit in the case of a construction of three layers is provided over a plurality of layers. And the crankshaft has eccentric core units in four places, each of which involving eccentricity in a different direction.

Moreover, each of the refrigerants compressed in each of the compression mechanism units may be discharged into the shell (single-stage compression), or the refrigerant compressed in one compression mechanism unit may be supplied to the other compression mechanism unit for further compression (multi-stage compression).

[0035]
(Compression unit) Based on the foregoing, the compression unit in the present invention can be described as follows:

"Including an annular cylinder, an annular rotary piston that is laid out in an inner circumferential area of the cylinder and rotates eccentrically while abutting with the inner circumferential surface of the cylinder, a vane that is laid out in a vane groove formed on the cylinder and can advance or retract in the direction of the central axis of the cylinder, and a spring that presses the vane onto the outer circumference of the rotary piston;

of the compression mechanism units, with regard to the compression mechanism unit laid out in the intermediate layer, the space surrounded by a pair of the partition plates that cover each of both end faces of the cylinder, the inner circumferential surface of the cylinder, and the outer circumferential surface of the rotary piston is divided by the vane into a pair of compression chambers; of the compression mechanism units, with regard to the compression mechanism unit laid out in an end layer, the space surrounded by the flame body that covers one end face of the cylinder, the partition plate that covers the other end face of the cylinder, the inner circumferential surface of the cylinder, and the outer circumferential surface of the rotary piston is divided by the vane into a pair of compression chambers; the crankshaft has eccentric units that are formed in directions that are different from each other, and at the same time that the crankshaft is rotatably supported by the means of bearings installed in the frame body, the crankshaft penetrates the central through-hole formed on the partition plate; and the eccentric core unit of the crankshaft penetrates through each of the inner circumferential areas of the rotary piston, and makes the rotary piston rotate eccentrically by means of rotation of the crankshaft, thereby increasing the volume of one of the compression chambers, and at the same time decreases the volume of the other compression chamber."

Reference Signs List

[0036]
10a First compression mechanism unit, 10b Second compression mechanism unit, 11a First cylinder, 11b Second cylinder, 12a First piston, 12b Second piston, 13a First vane groove, 13b Second vane groove, 14a First vane, 14b Second vane, 15a First spring, 15b Second spring, 16a First cylinder bolt hole, 16b Second cylinder bolt hole, 17a First cylinder bolt thread, 17b Second cylinder bolt thread, 20a First frame body, 20b Second frame body, 21 a First frame body bolt hole, 21b Second frame body bolt hole, 25a First bearing, 25b Second bearing, 30 Partition plate, 31 First divided partition piece, 32 Second divided partition piece, 33 Central through-hole, 33a First notched area, 33b Second notched area, 34 Division plane, 35 First assembling bolt hole, 35a First assembling bolt hole, 35b First assembling bolt hole, 35c First assembling bolt hole, 35d First assembling bolt hole, 36 Second assembling bolt hole, 36a Second assembling bolt hole, 36b Second assembling bolt hole, 36c Second assembling bolt hole, 40a Space, 40b Space, 50 Crankshaft, 51a First eccentric core unit, 51b Second eccentric core unit, 52a First bearing insertion unit, 52b Second bearing insertion unit, 53 Partition plate insertion unit, 60a Abutting bolt, 60b Abutting bolt, 61a Abutting bolt thread, 61b Abutting bolt thread, 62a Abutting bolt hole, 62b Abutting bolt hole, 63a First notched area, 63b First notched area, 64a First flange, 64b First flange, 65a Second notched area, 65b Second notched area, 66a Second flange, 66b Second flange, 71a First assembly short bolt, 71 b Second assembly short bolt, 72a First assembly long bolt, 72b Second assembly long bolt, 100 Rotary compressor (compressor), 101 Shell, 101a Upper shell, 101b Lower shell, 102 Motor, 102a Stator, 102b Rotor, 103 Compression unit, 104 Glass terminal, 105 discharge pipe, 106a First suction pipe, 106b Second suction pipe, 107 suction muffler, 300 Partition plate, 310 Divided partition piece, 320 Divided partition piece.

[Claim 1]
A rotary compressor comprising: a hermetic container; a driving unit and a compression unit laid out in the hermetic container; and a crankshaft that transmits rotation of the driving unit to the compression unit, wherein the compression unit is formed by a pair of compression mechanism units laminated with a partition plate being interposed there between, the partition plate is formed by a plurality of divided partition pieces that are divided by division planes in the radial direction, a hole for an assembling bolt is made on each of the divided partition pieces, of the holes for assembling bolts, a pair of holes for assembling bolts facing each other across the division plane are located symmetrically in relation to the division plane when the partition plate is formed by butting the divided partition pieces, and of the assembling bolts, the assembling bolts inserted in the pair of holes for assembling bolts facing each other across the division plane have nearly the same tightening force.

[Claim 2]
A rotary compressor comprising: a hermetic container; a driving unit and a compression unit laid out in the hermetic container; and a crankshaft that transmits rotation of the driving unit to the compression unit, wherein the compression unit is formed by laminated three or more compression mechanism units of three or more layers with a partition plate laid between them, the partition plate is formed by a plurality of divided partition pieces that are divided by division planes in the radial direction, a hole for an assembling bolt is made on each of the divided partition pieces, of the holes for assembling bolts, a pair of holes for assembling bolts facing each other across the division plane are located symmetrically in relation to the division plane when the partition plate is formed by butting the divided partition pieces, and of the assembling bolts, the assembling bolts inserted in the pair of holes for assembling bolts facing each other across the division plane have nearly the same tightening force.

[Claim 3]
The rotary compressor according to claim 1 or 2, wherein the surface pressure per unit area obtained by dividing the sum of the tightening forces of the assembling bolts inserted into the assembling bolt holes that are formed in the divided partition pieces by an abutment area between the divided partition piece and an end face of the cylinder is nearly equal in each of the divided partition pieces.