The present invention relates to a rotary-type fluid machine, and particularly to a rotary-type fluid machine including two eccentric-rotation type piston mechanisms arranged one on top of the other, the eccentric-rotation type piston mechanisms each having a cylinder formed with a cylinder chamber and a piston housed eccentrically in the cylinder chamber.
Conventionally, a rotary-type fluid machine is known which includes an eccentric-rotation type piston mechanism having a cylinder formed with a cylinder chamber and a piston housed eccentrically in the cylinder chamber. In the rotary-type fluid machine, one of the cylinder and the piston is formed as a fixed member and the other thereof is formed as a moving member attached eccentrically to a drive shaft, and the drive shaft is rotated to thereby rotate the moving member eccentrically to the fixed member.
In the rotary-type fluid machine, the drive shaft rotates while undergoing a periodic variation in the output torque thereof, and the variation in the output torque may cause a vibration or a noise in the rotary-type fluid machine.
PATENT DOCUMENT 1 discloses a rotary-type fluid machine capable of suppressing a variation in the output torque thereof. The rotary-type fluid machine is configured as a rotary compressor and includes two eccentric-rotation type piston mechanisms arranged vertically in tiers, each having two compression chambers on the same plane.
Specifically, an eccentric-rotation type piston mechanism (60) described above is formed, as shown in
Here, the piston (61) is housed in a cylinder chamber (C1, C2, C3, C4) such that as the cylinder (62) is eccentrically rotated, a phase difference of 180 degrees in volume change is made between the outside compression chamber (C1) and the inside compression chamber (C2).
The phase difference in volume change between the outside compression chamber (C1) and the inside compression chamber (C2) is shifted by 180 degrees, and thereby, the peak values of the output torque of the drive shaft by each compression chamber (C1, C2) are also shifted by 180 degrees. Therefore, the eccentric-rotation type piston mechanism (60) generates output-torque variations (the lines B and C of
Then, the output-torque variations by each compression chamber (C1, C2) affect each other, and thereby, the eccentric-rotation type piston mechanism (60) is capable of generating the total output torque of the drive shaft shown by the line A of
In the rotary compressor according to PATENT DOCUMENT 1, the two eccentric-rotation type piston mechanisms capable of suppressing an output-torque variation in this manner are arranged vertically in tiers, and a phase difference of 90 degrees in volume change is made between the cylinder chambers (C1, C2, C3, C4) of both eccentric-rotation type piston mechanisms (20). Specifically, the eccentricity directions of the rotation axes of both cylinders fixed to the drive shaft mutually have an angle difference of 90 degrees to the axial center of the drive shaft.
Similarly to
The rotational phases of both eccentric-rotation type piston mechanisms (20) are mutually shifted by 90 degrees, and thereby, the peak values of the output torque of the drive shaft by each eccentric-rotation type piston mechanism (20) are also shifted by 90 degrees. Therefore, the rotary compressor according to PATENT DOCUMENT 1 generates output-torque variations (the lines B and C of
Specifically, the peak value (P1) by the inside compression chamber (C2) of the upper eccentric-rotation type piston mechanism (20), the peak value (P3) by the inside compression chamber (C2) of the lower eccentric-rotation type piston mechanism (20), the peak value (P2) by the outside compression chamber (C1) of the upper eccentric-rotation type piston mechanism (20) and the peak value (P4) by the outside compression chamber (C1) of the lower eccentric-rotation type piston mechanism (20) appear at intervals of 90 degrees in this order.
Then, the output-torque variations by the two eccentric-rotation type piston mechanisms (20) affect each other, and thereby, the rotary compressor is capable of generating the total output torque of the drive shaft shown by the line A of
PATENT DOCUMENT 1: Japanese Patent No. 3757977
However, in the rotary compressor according to PATENT DOCUMENT 1 (hereinafter, referred to as the conventional rotary compressor), in order to reduce the vibration or noise thereof, the variation in the output torque of the drive shaft is desired to be further narrowed.
In view of the problem, it is an object of the present invention to provide a rotary-type fluid machine which includes two eccentric-rotation type piston mechanisms arranged one on top of the other, the eccentric-rotation type piston mechanisms each having a cylinder formed with a cylinder chamber and a ring-shaped piston housed eccentrically in the cylinder chamber, and which is capable of suppressing a variation in the output torque of a drive shaft and thereby reducing the vibration or noise of this rotary compressor.
A rotary-type fluid machine according to a first aspect of the present invention includes: a compression mechanism (5) including two eccentric-rotation type piston mechanisms (20) arranged one on top of the other; and a drive mechanism (30) including a drive shaft (33) for driving both two eccentric-rotation type piston mechanisms (20), in which the eccentric-rotation type piston mechanism (20) includes a cylinder member (21) formed with a cylinder chamber (C1, C2, C3, C4), a piston member (22) housed eccentrically in the cylinder chamber (C1, C2, C3, C4) such that the cylinder chamber (C1, C2, C3, C4) is partitioned into a first cylinder chamber (C1, C3) and a second cylinder chamber (C2, C4), and a blade member (23) partitioning each of the first cylinder chamber (C1, C3) and the second cylinder chamber (C2, C4) into a high-pressure side and a low-pressure side, one of the cylinder member (21) and the piston member (22) is formed as a fixed member and the other thereof is formed as a moving member making an eccentric rotational motion to the fixed member, and as the moving member makes the eccentric rotational motion, a phase difference of 180 degrees in volume change is made between the first cylinder chamber (C1, C3) and the second cylinder chamber (C2, C4) and a phase difference of 90 degrees in volume change is made between the cylinder chambers (C1, C2, C3, C4) of both eccentric-rotation type piston mechanisms (20).
Then, in the above rotary-type fluid machine, the moving member has a first surface (25) facing on the first cylinder chamber (C1, C3) and a second surface (26) facing on the second cylinder chamber (C2, C4), and the surface area of the first surface (25) is equalized to the surface area of the second surface (26). Particularly, it is preferable that the surface area of the first surface (25) in the circumferential directions is equalized to the surface area of the second surface (26) in the circumferential directions.
According to the first aspect, the first surface (25) and the second surface (26) of each moving member attached to the drive shaft (33) have the same surface area. Therefore, a load exerted on the moving member (a load working on the first surface (25)) by the gas pressure inside of the first cylinder chamber (C1, C3) can be equalized to a load exerted on the moving member (a load working on the second surface (26)) by the gas pressure inside of the second cylinder chamber (C2, C4).
Here, the output torque of the drive shaft (33) is determined by the load working on the moving member. Accordingly, the load working on the first surface (25) is equalized to the load working on the second surface (26), and thereby, the variations in the output torque of the drive shaft (33) by each eccentric-rotation type piston mechanism (20) can be equalized. Therefore, the peak values (P1, P2, P3, P4) of the variations in the output torque by each eccentric-rotation type piston mechanism (20) can also be equalized.
According to a second aspect of the present invention, in the rotary-type fluid machine according to the first aspect, the cylinder chamber (C1, C2, C3, C4) has a ring shape, and the piston member (22) is formed by a ring-shaped piston (22) housed eccentrically in the ring-shaped cylinder chamber (C1, C2, C3, C4) such that the cylinder chamber (C1, C2, C3, C4) is partitioned into an outside cylinder chamber (C1, C3) and an inside cylinder chamber (C2, C4). Then, the first cylinder chamber (C1, C3) is formed by the outside cylinder chamber (C1, C3) and the second cylinder chamber (C2, C4) is formed by the inside cylinder chamber (C2, C4).
In the rotary-type fluid machine according to the second aspect, for example, as shown in
In order to equalize the surface areas of the outer and inner circumferential surfaces, these surfaces are designed to differ in the height of each wall surface thereof in the axial directions. Specifically, the outer circumferential surface is longer in the circumferential directions than the inner circumferential surface, and hence, the outer circumferential surface is set to be lower in the axial directions than the inner circumferential surface to thereby equalize the surface areas of both surfaces.
According to a third aspect of the present invention, in the rotary-type fluid machine according to the second aspect, the ring-shaped piston (22) is formed with a straight portion (22d) arranged at a part thereof in the circumferential directions and continuing to the other parts thereof, and the cylinder member (21) is foamed with a groove portion (28) perpendicular to the straight portion (22d) and striding across the outside cylinder chamber (C1, C3) and the inside cylinder chamber (C2, C4). Then, the blade member (23) includes: an outside blade portion (23a) partitioning the outside cylinder chamber (C1, C3), an inside blade portion (23b) united with the outside blade portion (23a) and partitioning the inside cylinder chamber (C2, C4), and a concave portion (23c) formed between the outside blade portion (23a) and the inside blade portion (23b) and fitted slidably with the straight portion (22d) of the ring-shaped piston (22); and is formed by a concave blade (23) fitted slidably into the groove portion (28).
According to the third aspect, the blade member (23) prevents the ring-shaped piston (22) of the rotary-type fluid machine according to the second aspect from rotating on the axis thereof. Specifically, the ring-shaped piston (22) slides perpendicularly to the blade member (23) arranged in radial directions thereof and moves together with the blade member (23) only in the radial directions. Therefore, the ring-shaped piston (22) is restrained from being displaced in the rotational directions, and hence, the blade member (23) prevents the ring-shaped piston (22) from rotating on the axis thereof.
A rotary-type fluid machine according to a fourth aspect of the present invention includes: a compression mechanism (95) including two eccentric-rotation type piston mechanisms (100) arranged one on top of the other; and a drive mechanism (30) including a drive shaft (33) for driving both eccentric-rotation type piston mechanisms (100), in which the eccentric-rotation type piston mechanism (100) includes a cylinder (103) formed with a cylinder chamber (101, 102), a piston (104) housed in the cylinder chamber (101, 102) such that the piston (104) is eccentric to the cylinder chamber (101, 102), and a plurality of vanes (105, 107) partitioning the cylinder chamber (101, 102) into a first cylinder chamber (101) and a second cylinder chamber (102), and the piston (104) provides an eccentric rotational motion to the cylinder (103). Then, a phase difference of 90 degrees in volume change is made between the cylinder chambers (101, 102) of both eccentric-rotation type piston mechanisms (100). Further, the pistons (104) of both eccentric-rotation type piston mechanisms (100) each have a first surface (114) facing on the first cylinder chamber (101) and a second surface (115) facing on the second cylinder chamber (102), and the surface area of the first surface (114) is equalized to the surface area of the second surface (115).
According to the fourth aspect, the first surface (114) and the second surface (115) of each piston (104) attached to the drive shaft (33) have the same surface area. Therefore, a load exerted on the first surface (114) by the gas pressure inside of the first cylinder chamber (101) can be equalized to a load exerted on the second surface (115) by the gas pressure inside of the second cylinder chamber (102). This makes it possible to obtain the same advantages as the first aspect.
In the rotary-type fluid machine according to the present invention, the first surface (25) and the second surface (26) of each moving member have the same surface area, and thereby, the peak values (P1, P2, P3, P4) of variations in the output torque of the drive shaft (33) by each eccentric-rotation type piston mechanism (20) can be equalized. Therefore, the rotary-type fluid machine is capable of generating an output torque of a drive shaft shown by a line A of
Furthermore, in the rotary-type fluid machine according to the second aspect, as shown in
Moreover, in the rotary-type fluid machine according to the third aspect, the blade member (23) prevents the ring-shaped piston (22) from rotating on the axis thereof. Therefore, a member such as an Oldham coupling employed as a rotation prevention mechanism can be spared, thereby reducing the production cost of the rotary-type fluid machine.
In addition, in the rotary-type fluid machine according to the fourth aspect, the first surface (114) and the second surface (115) of each piston (104) have the same surface area, and thereby, the same advantages as the first aspect can be obtained. Therefore, the variation in the output torque becomes narrower than that in the output torque (the line A of
Embodiments of the present invention will be below described in detail with reference to the drawings.
As shown in
The casing (10) is a closed container formed by a vertically-long cylindrical body portion (11), an upper end plate (12) fixed to an upper-end part of the body portion (11) and a lower end plate (13) fixed to a lower-end part of the body portion (11). The upper end plate (12) is provided with a discharge pipe (15) penetrating the upper end plate (12). The discharge pipe (15) leads into the casing (10), and the inlet thereof opens in the space over the electric motor (30) arranged above inside of the casing (10). Further, the body portion (11) is provided with two suction pipes (14) penetrating the body portion (11). The suction pipes (14) are each connected to the compression mechanism (5) arranged below inside of the casing (10).
The rotary compressor (1) is configured to discharge a refrigerant compressed in the compression mechanism (5) to an inner portion (S2) of the casing (10) and thereafter send it out of the casing (10) through the discharge pipe (15). Therefore, when the rotary compressor (1) is in operation, the inside of the casing (10) is a high-pressure space (S2).
The electric motor (30) includes a stator (31) and a rotor (32). The stator (31) is cylindrical and fixed to the inner surface of the body portion (11) of the casing (10), and the rotor (32) is provided with a drive shaft (33) connected thereto such that the drive shaft (33) rotates together with the rotor (32).
The drive shaft (33) is formed inside with an oil supply passage (38) extending from the lower-end surface of the drive shaft (33) to the peripheral surface thereof. The drive shaft (33) is also provided at the lower end with an oil pump (34) supplying a lubricating oil inside of a storage portion (59) formed in a bottom part of the casing (10) through the oil supply passage (38) to each sliding parts of the compression mechanism (5) and a sliding surface formed between ring-shaped pistons (22) (described later) provided back to back with each other.
The drive shaft (33) is formed at a lower part with upper and lower adjacent eccentric portions (33b, 63b) shown in
The compression mechanism (5) includes two compression portions (eccentric-rotation type piston mechanisms) (20, 20). The compression portions (20, 20) each have substantially the same configuration, except that the axial centers of the eccentric portions (33b, 63b) are eccentric, and the compression portions (20, 20) are vertically adjacent to each other.
The upper and lower cylinders (21, 21) each include, as shown in
In the upper and lower cylinders (21, 21), the end surfaces of the outside cylinder portions (21a) of both cylinders (21, 21) are adherently fixed to each other to thereby form an inner space (S1) between the cylinders (21, 21). Then, the outer circumferential surfaces of the thus fixed cylinders (21, 21) are fixed to the inner circumferential surface of the casing (10) by welding or the like. In the inner space (51), the two ring-shaped pistons (22, 22) are housed.
As shown in
The piston portion (22a) is formed such that the surface area of the outer circumferential surface (first surface) (25) thereof is equalized to the surface area of the inner circumferential surface (second surface) (26) thereof. Specifically, the piston portion (22a) has a ring shape, and hence, the circumferential length (product of 2π and D1 of
In other words, the end plate (22c) of each ring-shaped piston (22, 22) is formed such that an outside outer-circumferential bottom surface (22e) thereof located outward from the piston portion (22a) is shallower from the top of the piston portion (22a) seen in
The upper and lower ring-shaped pistons (22, 22) are fixed to the drive shaft (33) by fitting each bearing portion (22b) into the corresponding eccentric portion (33b, 63b) of the drive shaft (33). Here, as described earlier, the axial centers of the upper and lower eccentric portions (33b, 63b) are eccentric to the axial center of the drive shaft (33), and the eccentricity directions thereof mutually have an angle difference of 90 degrees. Therefore, the rotation axes of the upper and lower ring-shaped pistons (22, 22) fitted into the eccentric portions (33b, 63b) are eccentric to the axial center of the drive shaft (33), and the eccentricity directions thereof mutually have an angle difference of 90 degrees. As a result, a phase difference of 90 degrees in volume change is made between the compression chambers (C1, C2, C3, C4) of both compression portions (20).
The upper and lower piston-side end plates (22c) have a micro clearance between, and a seal ring (24) is provided in the micro clearance. The seal ring (24) partitions the micro clearance into an inner part and an outer part, and the inner part inward from the seal ring (24) leads to the high-pressure space (S2) through the oil supply passage (38) of the drive shaft (33). Here, a lubricating oil is supplied into the inner part from the oil supply passage (38) to thereby keep the micro clearance at a high pressure. Then, the pressure inside of the seal ring (24) forms a back pressure for pressing the upper ring-shaped piston (22) toward the upper cylinder (21) and pressing the lower ring-shaped piston (22) toward the lower cylinder (21).
The upper and lower blades (23) are each, as shown in
In each compression portion (20, 20), the cylinder (21) and the ring-shaped piston (22) are each arranged as shown in
On the other hand, in the outside cylinder portion (21a) and the inside cylinder portion (21b) of each cylinder (21, 21), the parts thereof corresponding to the straight portion (22d) of the piston portion (22a) are each formed with a straight portion (
Then, each blade (23) is slidably fitted into the blade groove (28) while the concave portion (23c) is fitted with the straight portion (22d) of the piston portion (22a). Therefore, as described earlier, the outside blade portion (23a) partitions the outside compression chamber (C1, C3) into a high-pressure side (C1) and a low-pressure side (C3) and the inside blade portion (23b) partitions the inside compression chamber (C2, C4) into a high-pressure side (C2) and a low-pressure side (C4).
The outer circumferential surface of the inside cylinder portion (21b) and the inner circumferential surface of the outside cylinder portion (21a) are each formed by a cylindrical surface arranged concentrically with each other. Here, the inner circumferential surface of the outside cylinder portion (21a) is formed with a step (21d) having a smaller inner-circumferential diameter. Then, the ring-shaped compression chamber (C1, C2, C3, C4) as the compression chamber are formed between the inner circumferential surface having the smaller inner-circumferential diameter of the outside cylinder portion (21a) and the outer circumferential surface of the inside cylinder portion (21b).
Specifically, the inner circumferential part of the outside cylinder portion (21a) is formed with a concave portion (21e) for inserting the peripheral part of the end plate (22c) of each ring-shaped piston (22, 22). Then, the inner circumferential edge of the concave portion (21e) continues via the step (21d) to a bottom surface (21f) of the end plate (21c), and hence, the space between the step (21d) of the outside cylinder portion (21a) and the outer circumferential surface of the inside cylinder portion (21b) corresponds to the compression chamber (C1, C2, C3, C4).
Inside of the compression chamber (C1, C2, C3, C4) is arranged the piston portion (22a) of the ring-shaped piston (22). Specifically, the outer circumferential surface (25) of the piston portion (22a) has a smaller diameter than the step (21d) having the smaller inner-circumferential diameter of the outside cylinder portion (21a), while the inner circumferential surface (26) of the piston portion (22a) has a larger diameter than the outer circumferential surface of the inside cylinder portion (21b). Therefore, the outside compression chamber (C1, C3) is formed between the outer circumferential surface (25) of the piston portion (22a) and the step (21d) having the smaller inner-circumferential diameter of the outside cylinder portion (21a), while the inside compression chamber (C2, C4) is formed between the inner circumferential surface (26) of the piston portion (22a) and the outer circumferential surface of the inside cylinder portion (21b).
The surface area of the step (21d) as an inner circumferential surface of the outside cylinder portion (21a) and the surface area of the outer circumferential surface of the inside cylinder portion (21b) are equalized to each other such that these surfaces correspond to the outer circumferential surface (25) and the inner circumferential surface (26) of the piston portion (22a), respectively.
In each ring-shaped piston (22) and each cylinder (21), in a state where the outer circumferential surface (25) of the piston portion (22a) and the smaller-diameter inner circumferential surface of the outside cylinder portion (21a) are substantially in contact at one point with each other (strictly speaking, there is a micro clearance of a micron order, but in a state where the leakage of a refrigerant through the micro clearance is unproblematic), in a position where the phase is different by 180 degrees from the point of contact, the inner circumferential surface (26) of the piston portion (22a) and the outer circumferential surface of the inside cylinder portion (21b) are substantially in contact at one point with each other. According to this configuration, as the ring-shaped piston (22) rotates eccentrically, a phase difference of 180 degrees in volume change is made between the outside compression chamber (C1, C3) and the inside compression chamber (C2, C4).
Each cylinder (21) is formed with a suction port (41) penetrating the outside cylinder portion (21a) in a cylinder-radius direction. One open end of the suction port (41) faces on the low-pressure chamber (C1) of the outside compression chamber (C1, C3) while the other open end is provided with the suction pipe (14) inserted therein. Here, both suction ports (41) open toward the suction pipes (14) mutually in the same direction.
On the other hand, the piston portion (22a) is formed with a through hole (44) connecting the low-pressure chamber (C1) of the outside compression chamber (C1, C3) and the low-pressure chamber (C2) of the inside compression chamber (C2, C4).
In addition, each cylinder (21) is formed, as shown in
As can be seen in
On the other hand, the front end surface (upper end surface in
In addition, the front end surface (upper end surface in
As described above, each part of the ring-shaped piston (22), each cylinder (21, 21) and the blade (23) mutually slides in contact to thereby keep the compression chamber (C1, C2, C3, C4) airtight.
(Operation)
Next, a description will be given about a compression operation of the compression mechanism (5) in the above rotary compressor (1). Here, the upper and lower compression portions (20, 20) operate with mutually shifted by 90 degrees. Except for the phases thereof, each of them conducts the same operation, and hence, the operation of the upper compression portion (20) will be typically described.
First, upon starting the electric motor (30), the rotor (32) rotates, and this rotation is transmitted via the drive shaft (33) to the ring-shaped piston (22) of the upper compression portion (20). Then, the piston portion (22a) of the ring-shaped piston (22) makes a reciprocating motion together with the blade (23) in the radial directions along the blade groove (28), and the straight portion (22d) of each ring-shaped piston (22) makes a reciprocating motion perpendicularly to the radial directions inside of the concave portion (23c) of the blade (23).
Here, the ring-shaped piston (22) slides perpendicularly to the blade (23) arranged in cylinder radial directions and moves together with the blade (23) only in the cylinder radial directions. Therefore, the ring-shaped piston (22) is restrained from being displaced in the rotational directions, and hence, the blade (23) configures a rotation prevention mechanism for restraining the ring-shaped piston (22, 22) from rotating on the axis thereof.
The above reciprocating motions in the radial directions and in the directions perpendicular to the radial directions are combined, and thereby, the piston portion (22a) revolves with respect to the outside cylinder portion (21a) and the inside cylinder portion (21b) of each cylinder (21), so that the compression portion (20) conducts a predetermined compression operation.
Specifically, in the outside compression chamber (C1, C3), the volume of the low-pressure chamber (C1) is substantially at the minimum in the state of
This time, the low-pressure chamber (C1) becomes the high-pressure chamber (C3) for compressing the refrigerant and a new low-pressure chamber (C1) is formed on the other side of the blade (23). As the drive shaft (33) rotates further, the suction of the refrigerant is repeated in the low-pressure chamber (C1), while the volume of the high-pressure chamber (C3) decreases and the refrigerant is compressed in the high-pressure chamber (C3). When the pressure of the high-pressure chamber (C3) has become a predetermined value and the differential pressure between it and the discharge space has reached a set value, the high-pressure refrigerant of the high-pressure chamber (C3) opens the delivery valve and flows into the high-pressure space (S2) inside of the casing (10) from the discharge space.
On the other hand, in the inside compression chamber (C2, C4), the volume of the low-pressure chamber (C2) is substantially at the minimum in the state of
The drive shaft (33) makes one rotation and the state comes to
The outside compression chamber (C1, C3) starts to discharge the refrigerant substantially in the timing of
According to the first embodiment, in the ring-shaped piston (22), the outer circumferential surface (25) and the inner circumferential surface (26) of the piston portion (22a) have the same surface area. Therefore, a load exerted on the ring-shaped piston (22) (a load working on the outer circumferential surface (25)) by the gas pressure inside of the outside compression chamber (C1, C3) can be equalized to a load exerted on the ring-shaped piston (22) (a load working on the inner circumferential surface (26)) by the gas pressure inside of the inside compression chamber (C2, C4).
Here, the output torque of the drive shaft (33) is determined by the load working on the ring-shaped piston (22). Accordingly, the load working on the outer circumferential surface (25) is equalized to the load working on the inner circumferential surface (26), and thereby, the variations in the output torque of the drive shaft (33) by each compression portion (20) can be equalized. Therefore, the rotary compressor (1) according to the first embodiment generates the variations in the output torque of the drive shaft (33) shown in
As can be seen in
In addition, according to the first embodiment, the blade (23) prevents the ring-shaped piston (22) from rotating on the axis thereof. Therefore, a member such as an Oldham coupling employed as a rotation prevention mechanism can be spared, thereby reducing the production cost of the rotary-type fluid machine.
In the rotary compressor (90) according to the second embodiment, the compression portion (100) is of a multi-vane type, which is different from the rotary compressor (1) according to the first embodiment. The rotary compressor (90) is also different from the first embodiment in the configuration for making a phase difference of 90 degrees in volume change between compression chambers (101, 102) of the vertically-arranged compression portions (100). Only those differences will be below described.
As shown in
The vanes (105, 107) are attached to the cylinder (103) such that each of them is movable back and forth in the length direction thereof. The tip of each vane (105, 107) protrudes inward from the inner-circumferential wall surface of the cylinder (103) and comes into contact with and presses the outer-circumferential wall surface of the piston (104). Specifically, each vane (105, 107) is provided at the end thereof with a vane spring (116, 117), respectively, and the vane spring (116, 117) forces, onto the piston (104), the corresponding vane (105, 107) movable back and forth in the length direction. The force thereby keeps the tip of each vane (105, 107) constantly staying in contact with and pressing the outer-circumferential wall surface of the piston (104), even though the piston (104) makes an eccentric rotational motion.
Here, the vanes (105, 107) are attached to the cylinder (103) such that each of them comes into contact with and presses the outer-circumferential wall surface of the piston (104) in a position mutually shifted by 180 degrees around the drive shaft (33) as the center. Therefore, as the piston (104) makes an eccentric rotational motion, a phase difference of 180 degrees in volume change is made between the first compression chamber (101) and the second compression chamber (102).
The cylinder (103) is formed with a first suction port (108) and a first discharge port (110) leading to the first compression chamber (101), and the first suction port (108) is provided with a first suction valve (113). Further, the cylinder (103) is formed with a second suction port (109) and a second discharge port (111) leading to the second compression chamber (102), and the second suction port (109) is provided with a second suction valve (112).
The piston (104) is attached such that the axial center thereof is eccentric to the axial center of the drive shaft (33). In terms of the outer-circumferential wall surface of the piston (104), a right outer-circumferential wall surface (first surface) (114) facing on the first compression chamber (101) and a left outer-circumferential wall surface (second surface) (115) facing on the second compression chamber (102) have the same surface area. Specifically, the tip of each vane (105, 107) comes into contact with and presses the outer-circumferential wall surface of the piston (104) in a position mutually shifted by 180 degrees around the drive shaft (33) as the center, thereby equalizing the circumferential lengths of both outer-circumferential wall surfaces (114, 115). Then, both outer-circumferential wall surfaces (114, 115) have the same height in the axial directions to thereby equalize the surface areas of both outer-circumferential wall surfaces (114, 115). As shown in
Here, the upper and lower pistons (104) are attached to eccentric portions (106) of the drive shaft (33) such that the eccentricity directions of the axial centers of both pistons (104) mutually have an angle of 180 degrees to the axial center of the drive shaft (33). Besides, the opening directions of the first and second suction ports (108, 109) in one of the above compression portions (100) are shifted by 90 degrees with respect to the opening directions of the first and second suction ports (108, 109) in the other compression portion (100), respectively. Then, the opening directions of the first and second discharge ports (110, 111) in the one compression portions (100) are shifted by 90 degrees with respect to the opening directions of the first and second discharge ports (110, 111) in the other compression portion (100), respectively.
According to this configuration, a phase difference of 90 degrees in volume change is made between the compression chambers (101, 102) of both compression portions (100).
According to the second embodiment, as the piston (104) rotates, the volume of each compression chamber (101, 102) increases and thereby a gas refrigerant is sucked into each compression chamber (101, 102), while the volume of each compression chamber (101, 102) decreases and thereby the sucked gas refrigerant is compressed and discharged from each compression chamber (101, 102). This operation is repeated, and thereby, the compression portions (100) conduct the compression operation for a gas refrigerant.
According to the second embodiment, each compression portion (100) is of a multi-vane type. Therefore, as compared with the first embodiment, a load exerted on the piston (104) (a load working on the right outer-circumferential wall surface (114)) by the gas pressure inside of the first compression chamber (101) can be easily equalized to a load exerted on the piston (104) (a load working on the left outer-circumferential wall surface (115)) by the gas pressure inside of the second compression chamber (102).
Specifically, according to the first embodiment, the ring-shaped compression chambers (C1, C2, C3, C4) are formed on the inside and outside of the piston portion (22a), and thereby, the outer circumferential surface (25) and the inner circumferential surface (26) of the piston portion (22a) each have a mutually different length in the circumferential directions. Therefore, in order to equalize the gas pressures working on the outer circumferential surface (25) and the inner circumferential surface (26), the piston portion (22a) needs to be machined such that the outer circumferential surface (25) and the inner circumferential surface (26) each have a different height in the axial directions to thereby equalize the surface areas of the outer circumferential surface (25) and the inner circumferential surface (26).
However, according to the second embodiment, the compression chambers (101, 102) are formed on both sides of the piston (104), and the points at which the vanes (105, 107) come into contact with and press the outer-circumferential wall surface of the piston (104) are mutually shifted by 180 degrees around the drive shaft (33) as the center. Therefore, both outer-circumferential wall surfaces (114, 115) have the same circumferential length, so that the surface areas of the outer circumferential surface (25) and the inner circumferential surface (26) can be equalized without machining the piston (104) such that both outer-circumferential wall surfaces (114, 115) each have a different height in the axial directions. As described above, both loads exerted on the piston (104) can be more easily equalized than the first embodiment.
The thus configured compression portions (100) are vertically arranged, and thereby, as can be seen in
The above embodiments may be configured as follows.
In the first embodiment, the ring-shaped piston (22) is formed as a moving member, but the present invention is not necessarily limited to this, and hence, the cylinder (21) may be formed as a moving member. In this case, the step (21d) having the smaller inner-circumferential diameter of the outside cylinder portion (21a) configures the first surface and the outer circumferential surface of the inside cylinder portion (21b) configures the second surface. Then, the surface area of the step (21d) of the outside cylinder portion (21a) is equalized to the surface area of the outer circumferential surface of the inside cylinder portion (21b).
Furthermore, in the first embodiment, in order to make a phase difference of 90 degrees in volume change between the compression chambers (C1, C2, C3, C4) of both compression portions (20), both eccentric portions (33b, 63b) are fixed to the drive shaft (33) such that the eccentricity direction of each eccentric portion (33b, 63b) mutually has an angle of 90 degrees. However, the present invention is not necessarily limited to this, and hence, the eccentricity directions may be mutually shifted by a predetermined angle. Here, a phase difference of 90 degrees in volume change between the compression chambers (C1, C2, C3, C4) of both compression portions (20) may not be made by only shifting each eccentricity direction by the predetermined angle. Therefore, if necessary, an adjustment needs to be made such that the opening direction of each suction port (41) mutually has a predetermined angle around the drive shaft (33) as the center, thereby making a phase difference of 90 degrees in volume change between the compression chambers (C1, C2, C3, C4).
For example, if a setting is given such that the eccentricity directions of the eccentric portions (33b, 63b) mutually have an angle of 180 degrees, then the opening direction of each suction port (41) is mutually shifted by an angle of 90 degrees, and thereby, a phase difference of 90 degrees in volume change can be made between the compression chambers (C1, C2, C3, C4) of both compression portions (20). As a result, an improvement can be made in the balance of a centrifugal force working on the rotary compressor (1) by the rotation of the drive shaft (33).
In contrast, in the second embodiment, the eccentric portions (106, 106) are fixed to the drive shaft (33) such that the eccentricity direction of each eccentric portion (106, 106) mutually has an angle of 180 degrees. Besides, the opening directions of the first and second suction ports (108, 109) in one of the compression portions (100) are shifted by 90 degrees with respect to the opening directions of the first and second suction ports (108, 109) in the other compression portion (100), respectively. Then, the opening directions of the first and second discharge ports (110, 111) in the one compression portions (100) are shifted by 90 degrees with respect to the opening directions of the first and second discharge ports (110, 111) in the other compression portion (100), respectively.
However, the present invention is not necessarily limited to this, and for example, each eccentric portion (106, 106) may be fixed to the drive shaft (33) such that the eccentricity direction thereof mutually has an angle of 90 degrees. In this case, the opening directions of the first and second suction ports (108, 109) in the one compression portion (100) are set to the same as the opening directions of the first and second suction ports (108, 109) in the other compression portion (100), respectively. Then, the opening directions of the first and second discharge ports (110, 111) in the one compression portions (100) are set to the same as the opening directions of the first and second discharge ports (110, 111) in the other compression portion (100), respectively.
The aforementioned embodiments are essentially preferred illustrations, and hence, the scope of the present invention, the one applied thereto or the use thereof is not supposed to be limited.
As described hereinbefore, the present invention is useful for a rotary-type fluid machine, and particularly to a rotary-type fluid machine including two eccentric-rotation type piston mechanisms arranged one on top of the other, the eccentric-rotation type piston mechanisms each having a cylinder formed with a cylinder chamber and a piston housed eccentrically in the cylinder chamber.
Number | Date | Country | Kind |
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2008-013670 | Jan 2008 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2009/000267 | 1/23/2009 | WO | 00 | 7/23/2010 |