CN1170088A - Fluid compressor - Google Patents

Abstract

Provided is a fluid compressor capable of dynamically balancing a crankshaft having a crank that rotates a drum. This fluid compressor has a compression mechanism 3 that compresses refrigerant gas that enters between the cylinder 5 and the roller 11 by rotating the roller 11 eccentrically arranged inside the cylinder 5. In this fluid compressor, the compression mechanism 3 There is a crankshaft 9 arranged in the drum 11, and the crankshaft 9 has a crank 9a that makes the drum 11 rotate in the cylinder 5, and the crankshaft 9 is provided with two balance weights 9b on both sides of the crank 9a in the axial direction. 10.

Description

fluid compressor

The present invention relates to a compression mechanism for compressing a fluid to be compressed, such as refrigerant gas, used in a refrigeration cycle apparatus, for example.

Conventionally, fluid compressors have been used in refrigeration cycle devices to compress and discharge refrigerant gas introduced into the interior. Japanese Patent Publication No. 7-107391 discloses a helical vane type fluid compressor as a representative of such fluid compressors. Because the structure of this compressor is that the cylinder and the drum rotate, and the peripheral speed is high, the sliding loss at the bearing must be considered. Therefore, the fluid compressor shown in FIG. 3 is designed so that the peripheral speed is small to reduce the sliding loss.

1 in Fig. 3 indicates that the axial direction is a sealed casing with a horizontal direction. A compression mechanism 3 and an electric motor 4 are housed in the sealed case 1 . That is, the compression mechanism 3 is located on the right side in FIG. 3 , and the motor 4 is located on the left side of the seal case 1 substantially in the middle in the axial direction.

The above-mentioned compression mechanism 3 has a cylinder 5 having a hollow cylindrical body with open ends on both sides. On one side of the above-mentioned cylinder 5 (the left side of the figure), the main bearing 6 is installed and fixed with a fixture 7, and the opening part of the cylinder 5 is closed. On the other side (the right side of the figure), a fixed secondary bearing 8 is installed with a fixture 7 to close the opening of the cylinder.

The crankshaft 9 passes through the axis of the main bearing 6 and the auxiliary bearing 8, is supported by the bearings and can rotate freely. The crankshaft 9 not only penetrates the cylinder 5 located between the main bearing 6 and the sub bearing 8, but also protrudes from the main bearing 6 to the left in the figure, and constitutes a rotating shaft 9Z of the electric motor 4 described later. Moreover, a crank 9a integrated with the crankshaft 9 is provided on the circumferential surface of the crankshaft 9 between the main bearing 6 and the auxiliary bearing 8, and the axis b of the crank 9a is eccentric to the axis a of the crankshaft by a certain distance e.

A drum 11 is placed between the crankshaft 9 and the cylinder 5 . The drum 11 is a cylindrical body with both ends open, and its axial length is the same as that of the cylinder 5 .

A stepped inner cavity 12 is formed on the inner peripheral surface of the drum 11. In particular, the position opposite to the crank 9a of the above-mentioned crankshaft 9 has the same width as the crank, and is an inner cavity support that is in free rotation and sliding contact with its outer peripheral surface. Site 12a.

On the outer circumferential surface of the drum 11, a spiral groove 14 with a gradually decreasing pitch is provided from the end of the side where the auxiliary bearing 8 is installed to the end of the side where the main bearing 6 is installed. Into and out of the free helical blade 15.

In addition, the motor 4 described above is composed of a rotor 45 and a stator 46 . The rotor 45 is embedded in the rotating shaft 9Z of the crankshaft 9 protruding from the main bearing 6 , and the stator 46 is embedded in the inner peripheral surface of the casing main body 1 a with a certain clearance from the outer peripheral surface of the rotor 45 .

A fluid compressor of this configuration, as described below, compresses refrigerant gas as a fluid to be compressed. That is, the electric motor 4 is energized to rotate the crankshaft 9 together with the rotor 45 . The rotational force of the crankshaft 9 is transmitted to the drum 11 through the crank 9a.

The crank 9a is arranged eccentrically. Here, the drum 11 is supported on the crank 9a because the inner cavity support portion 12a of the drum 11 can freely rotate with each other. Moreover, because the Oldham coupling mechanism 13 arranged between the main bearing 6 and the drum 11 limits the rotation of the drum, the drum 11 does not rotate when it rotates.

In addition, low-pressure refrigerant gas is sucked in from the suction pipe 17 and introduced into the compression chamber 16 . As the drum 11 rotates, the rotational contact position of the drum with respect to the inner peripheral surface of the cylinder 5 gradually moves in the circumferential direction, and the vane 15 enters and exits the helical groove 14 . That is: the blade 15 moves in and out in the radial direction of the drum 11 .

The refrigerant gas entering the compression chamber 16 is sequentially sent in the compression chamber 16 along with the rotation of the drum 11 from the position where the blades 15 form a spiral shape.

Because the above-mentioned blades 15 are set at a distance from one side of the suction part A to the discharge part B, the volume of the compression chamber 16 separated by the blades gradually decreases, so the refrigerant gas is compressed when it is sequentially delivered to the compression chamber, The compression chamber on the side closest to the discharge part B rises to a predetermined pressure and reaches a high pressure state.

The high-pressure gas is discharged from the compression chamber 16 of the discharge part B, and enters the space on the motor 4 side. Then, enter and fill the space on one side of the compression mechanism 3 . Since the open end of the discharge pipe 18 is opposite to this space, the high-pressure gas enters the discharge pipe and from there enters the condenser.

In this way, in the compression mechanism 3 of the present fluid compressor, since the roller 11 is rotated relative to the fixed cylinder 5, the circumferential speed of the roller 11 is reduced compared with the conventional screw blade type compression mechanism. Therefore, the sliding loss of the roller 11 on the thrust surface is reduced, thereby improving the compression efficiency.

The above-mentioned conventional drum 11 has the following problems in the fluid compression mechanism that performs rotational motion. That is, since the crank 9a is formed on the crankshaft 9, it is necessary to eliminate the unbalance due to the rotational movement of the drum 11, and to reduce the vibration. For this purpose, a balance weight 9 b is provided on the circumferential surface between the supporting portion of the main bearing 6 and the supporting portion of the auxiliary bearing 8 .

However, since dynamic balance cannot be obtained when there is only one balance weight, it is necessary to install at least one balance weight on each of the main bearing side and the sub bearing side of the crank 9a. However, the problem is that when using the crankshaft 9 integrated with the two balance weights, the balance weight cannot pass through the inner chamber support portion 12a and cannot be assembled. In addition, although it is conceivable to use a balance weight that is thinner than that of the cavity support portion 12a, it is difficult to obtain sufficient dynamic balance.

In addition, although the second balance counterweight can also be arranged on one side of the motor 4 . However, the crankshaft 9 tends to bend during high-speed rotation.

Therefore, an object of the present invention is to provide a fluid compressor that compresses the compressed fluid introduced between the cylinder and the roller by rotating the roller eccentrically arranged in the cylinder, and in this fluid compressor, the The crankshaft with the crank that rotates the drum is dynamically balanced and easy to assemble.

In order to achieve the purpose of solving the above-mentioned problems, the invention described in claim 1 is: the compression mechanism of the fluid compressor is to compress the compressed fluid that enters between the above-mentioned cylinder and the above-mentioned roller by rotating the eccentrically arranged roller in the cylinder, The compression mechanism has a crankshaft installed in the drum, and the crankshaft has a crank that rotates the drum in the cylinder, and two balance weights are provided on both sides of the crank in the axial direction of the crankshaft.

According to the invention described in claim 2, in the invention described in claim 1, the crankshaft is supported by a main bearing and a sub bearing, and the balance weight is provided between the main bearing and the sub bearing.

The invention described in claim 3 is: in the invention described in claim 1, one of the balance weights is integrated with the crankshaft, and the other balance weight is freely attached to the crankshaft.

The invention described in Claim 4 is the invention described in Claim 3, wherein the relative movement of the other balance weight relative to the crankshaft in the circumferential direction and the axial direction is restricted.

The invention described in claim 5 is: in the invention described in claim 1, 2 or 3, the above-mentioned compression mechanism has spiral grooves provided along the circumferential surface of the above-mentioned roller with gradually decreasing pitches, and has a groove embedded in the The helical vane in the helical groove, which divides the space between the helical blade and the above-mentioned cylinder into a plurality of compression chambers whose volumes gradually decrease, enters the space between the helical grooves and the compression chamber on the side where the pitch of the helical groove is larger. The fluid to be compressed is compressed while being gradually sent to the compression chamber on the side with the smaller pitch of the helical grooves.

The following effects can be produced by the above-mentioned device. In the invention described in claim 1, on the crankshaft with the crank that makes the drum rotate in the cylinder, two balance weights that are separated from the crank are arranged in the axial direction, so dynamic balance can be achieved, and weight balance and balance can be ensured. balance of moments.

In the invention described in Claim 2, since the balance weight is provided between the main bearing and the sub bearing that support the crankshaft, bending of the crankshaft that occurs when the balance weight is mounted on the motor side, for example, can be prevented.

In the invention described in plan 3, because one of the balance weights is integrated with the crankshaft, and the other balance weight is formed to cooperate with the crankshaft, it is possible to install another balance weight after the crankshaft is assembled on the drum. A counterweight. Therefore, when assembling the crankshaft to the drum, for example, even if there is a part having a small inner diameter such as a part in contact with the crank on the drum, the crankshaft can be easily inserted.

In the invention described in Claim 4, since the relative movement of the other balance weight relative to the crankshaft in the circumferential direction and the axial direction is restricted, dynamic balance can be maintained.

In the invention described in Claim 5, the compression mechanism has spiral grooves provided along the circumferential surface of the drum and formed with gradually smaller pitches, and has spiral blades embedded in the spiral grooves freely. The space between the cylinder and the above-mentioned cylinder is divided into a plurality of compression chambers whose volumes gradually decrease, and the compressed fluid entering the compression chamber on the side with a larger pitch of the helical grooves is gradually conveyed toward the pitch of the helical grooves. The compression chamber on one side is smaller and the other side is compressed. Therefore, it is possible to provide a helical vane type fluid compressor with good assembly performance.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The helical vane fluid compressor shown here is a compressor used in a refrigerating cycle such as an air conditioner. In addition, in this figure, the same functional parts as those in FIG. 3 are denoted by the same symbols.

Fig. 1 is a longitudinal sectional view of a fluid compressor according to an embodiment of the present invention.

Figure 2 shows the essential parts of the apparatus of Figure 1 .

Fig. 3 is a longitudinal sectional view of a conventional fluid compressor.

As shown in FIG. 1 , the sealed casing 1 is composed of a casing main body 1 a with two open ends in the axial direction, an upper cover 1 b closing one opening of the casing main body 1 a, and a cover plate 1 c closing the opening at the other end.

The compression mechanism 3 and the motor 4 are put into the sealed casing 1 . That is, the compression mechanism 3 is located on the right side in FIG. 1 , and the motor 4 is located on the left side of the seal case 1 substantially in the middle of the axial direction.

The above-mentioned compression mechanism 3 has a hollow cylindrical cylinder 5 with both ends opened, and a pair of flanges 5a, 5b protruding outwards are provided on the outer peripheral surface of both ends. At least one flange 5a of the air cylinder 5 is press-fitted to the housing main body 1a constituting the sealed housing 1 to determine and fix the position of the air cylinder 5 .

On one side of the above-mentioned cylinder 5 (the left side in the drawing), the main bearing 6 is mounted and fixed by a fixing member 7, and the opening of the cylinder is closed. On the other side (the right side of the figure), a fixed sub-bearing 8 is installed through a fixture 7 to close the opening of the cylinder.

The crankshaft 9 passes through the shaft centers of the main bearing 6 and the sub bearing 8 and is rotatably supported by the bearings. The crankshaft 9 not only penetrates the cylinder 5 between the main bearing 6 and the sub bearing 8, but also protrudes from the main bearing 6 to the left in the drawing, and constitutes a rotating shaft 9Z of the electric motor 4 described later.

Now, the crankshaft 9 described above will be described. A crank 9a integrated with the crankshaft 9 is arranged on the circumferential surface between the above-mentioned main bearing 6 and the auxiliary bearing 8, and the position of the crank 9a is separated from the bearing by a certain distance, and the axis b of the crank 9a and the axis a of the crankshaft deviate from a certain dimension e.

A balance counterweight 9b integrated with the crankshaft is provided adjacent to the left side of the crank 9a. The balance weight 9b is provided eccentrically on the circumferential surface on the opposite side to the direction in which the first crank 9a extends eccentrically.

Moreover, a balance weight 10 that is different from the crankshaft 9 is embedded adjacent to the right side of the crank 9a. The balance weight 10 is provided eccentrically on the circumferential surface opposite to the direction in which the crank 9a eccentrically protrudes. Moreover, as shown in FIGS. 2( a ) and ( b ), the movement of the balance weight 10 relative to the crankshaft 9 in the circumferential direction is limited by a key 50 that cooperates with a key groove 9 c provided on the crankshaft 9 . Moreover, the movement of the balance weight 10 relative to the crankshaft 9 in the axial direction is limited by the snap ring 50 . The sequence of embedding the balance weight 10 on the crankshaft 9 is described below.

Between this crankshaft 9 and the above-mentioned cylinder 5, put the drum 11 made of materials such as aluminum alloy which is lighter in specific gravity than iron. The drum 11 is a cylinder with both ends open, and its axial length is the same as that of the cylinder.

A stepped inner cavity 12 is formed on the inner peripheral surface of the drum 11, especially the position of the crank 9a relative to the above-mentioned crankshaft 9 has the same width as the crank 9a, and is in rotatable and sliding contact with the outer peripheral surface of the crank 9a. Lumen support part 12a.

Thereby, the axis b of the drum 11 is aligned with the axis b of the crank 9a, and is eccentric by a dimension e with respect to the axis a of the cylinder 5 or the like. Also, the dimensions are set such that a part of the outer circumference of the drum 11 is in rotational contact with a part of the inner circumference of the air cylinder 5 in the axial direction.

Moreover, the sliding connection between the crank 9a of the above-mentioned crankshaft 9 and the inner chamber support portion 12a of the drum 11 is set at a position equal to the left and right distance from the axial middle of the drum 11 .

An Oldham coupling mechanism 13 is arranged between the end of the drum 11 on one side close to the main bearing 6 and the position of the main bearing 6 . This coupling mechanism 13 restricts the rotation of the drum 11 .

As a result, when the crankshaft 9 rotates, the crank 9a provided here rotates eccentrically, and the drum 11 supported on the outer peripheral surface of the crank 9a performs a rotational movement eccentrically.

In this way, as the drum 11 rotates, the rotating contact portion of the outer circumference of the drum 11 with respect to the inner circumference of the air cylinder 5 gradually moves along the circumferential direction of the air cylinder 5 .

The outer peripheral surface of the above-mentioned drum 11 is provided with a spiral groove 14 whose spacing gradually decreases from one end where the auxiliary bearing 8 is installed to one end where the main bearing 6 is installed. In slot 14.

The blades 15 are made of high-sliding materials such as fluorine-containing resin, and their inner diameters are larger than the outer diameters of the rollers 11 . That is, the vane is forcibly embedded in the helical groove 14 in a reduced-diameter state, and as a result, when assembled in the cylinder 5 together with the drum 11, the expansion deformation of the outer peripheral surface of the vane 15 is always consistent with the inner peripheral surface of the cylinder 5. Elastic contact.

As mentioned above, when the drum 11 rotates and moves relative to the rotational contact position of the cylinder 5, the vane 15 enters the helical groove 14 as it approaches the rotational contact position, and the outer peripheral surface of the vane 15 at the rotational contact position meets the surface of the drum 5. The outer peripheral surface becomes completely the same surface.

On the contrary, when passing through the rotating contact position, corresponding to the distance to here, the blade 15 protrudes from the helical groove 14, and at the opposite position of 180° through the axis b and the rotating contact position, the protruding length of the blade 15 reaches maximum. Subsequently, when the rotating contact part is approached again, the above-mentioned actions are repeated.

Now let’s study the cross-sectional view of the cylinder 5 and the cylinder 11 along the radial direction. The cylinder 11 is eccentrically placed in the cylinder 5, and because a part of the circumference of the cylinder is in rotational contact with the cylinder, three cylinders are formed between the cylinder 5 and the cylinder 11. Lunar space.

Looking at the above-mentioned space along the axial direction, the blade 15 is rotatably installed in the helical groove 14 of the drum 11 . Since the outer peripheral surface thereof is in rotational contact with the inner peripheral surface of the cylinder 5, the vane 15 separates the drum 11 and the cylinder 5 into a plurality of spaces.

These partitioned spaces are called compression chambers 16 . . . The volume of each compression chamber 16 is set by the above-mentioned helical groove 14, and its volume gradually decreases from one end of the sub-bearing 8 to one end of the main bearing 6.

In addition, a suction pipe 17 is provided to pass through the cover plate 1c constituting the above-mentioned airtight case 1, and a discharge pipe 18 is connected to a position near the suction pipe. The suction pipe 17 communicates with an evaporator constituting a refrigerating cycle, and the discharge pipe 18 communicates with a condenser constituting the same refrigerating cycle (both are not shown).

The suction pipe 17 penetrating through the sealing case cover plate 1 c is connected to the coupling portion 8 a provided on the sub-bearing 8 inside the sealing case 1 . The connecting portion 8a has an opening on the coupling surface between the sub-bearing 8 and the cylinder 5 . The opening end of the discharge pipe 18 faces the inside of the sealed case 1 .

At the flange 5b of the air cylinder 5 opposite to the opposite end of the above-mentioned sub-bearing connecting portion 8a, there is provided a recessed portion 19 for temporarily storing gas entering from the suction pipe 17.

A concave portion (not shown) for gas passage is provided at one end of the drum 11 . Regardless of the position of the rotating drum 11, the recessed portion for the gas passage is always opposed to the above-mentioned recessed portion 19 provided on the air cylinder 5. As shown in FIG.

Therefore, the buffer portion 21 with a large volume is formed by these recessed portions for gas passages and the recessed portion 19, and the gas entering from the suction pipe 17 is temporarily stored.

A discharge hole 24 is provided on a side surface of the above-mentioned main bearing 6 . The side end space of the air cylinder 5 and the drum 11 communicates with the space on the side of the motor 4 through the discharge hole 24 .

Since the pitch of the spiral groove 14 is set, the compression chamber 16 on the side where the buffer portion 21 is provided becomes the suction portion A, and the compression chamber 16 on the side where the discharge hole 24 is provided on the opposite side becomes the discharge portion. b.

Furthermore, the first space 25 is surrounded by the main bearing 6 , the crankshaft 9 and the drum 11 . The second space 26 is surrounded by the sub bearing 8 , the crankshaft 9 and the drum 11 .

From one end face of the auxiliary bearing 8 of the crankshaft 9 to the support of the main bearing 6 in the middle, a guide hole 28 is provided along the axis of the crankshaft. The opening end of the guide hole 28 and the opening end of the shaft support of the auxiliary bearing 8 are closed by a closing plate 30 mounted on the end surface of the auxiliary bearing by a fixing piece 29 .

The guide hole 28 communicates with the outer peripheral surface of the crankshaft 9 through a plurality of oil holes described later.

That is, the first oil hole 31 is provided in a portion communicating with the above-mentioned first space 25 . The second oil hole 32 is provided in a portion communicating with the above-mentioned second space 26 .

The opening of the third oil hole 33 faces the supporting portion of the sub-bearing 8 . The opening of the fourth oil hole 34 is on the circumferential surface of the crank 9 a and faces the second cavity support portion 12 a of the drum 11 . The opening of the fifth oil hole 35 faces the supporting portion of the main bearing 6 . An oil supply passage S is formed by the guide hole 28 and the third to fifth oil holes 33 to 35 .

An oil pool 37 for storing lubricating oil is formed at the inner bottom of the sealed case 1 . An oil suction pipe 38 connected to the shaft support portion of the auxiliary bearing 8 is immersed in the lubricating oil in the oil pool 37 .

The connecting portion of the oil suction pipe 38 communicates with the sliding contact surface of the crankshaft 9 which is the inner peripheral surface of the sub-bearing 8 supporting portion. At the crankshaft point opposite thereto, a charge pump 39 is arranged.

On the flange 5a of the air cylinder 5 pressed into the housing main body 1a, a gas guide hole 43 is provided on the upper side of the figure, and an oil guide hole 44 is provided at a position immersed in lubricating oil in the lower side oil pool 37.

Each guide hole 43, 44 penetrates both sides of the flange 5a, and communicates with the inside of the sealed case 1 separated by the flange. That is, the gas guide hole 43 is used to guide the high-pressure gas discharged from the discharge portion B, and the oil guide hole 44 is used to guide the lubricating oil in the oil pool 37 .

In addition, the above-mentioned electric motor 4 is constituted by a rotor 45 and a stator 46 . The rotor 45 is embedded on the rotating shaft 9Z of the crankshaft 9 protruding from the main bearing 6 , and the stator 46 is embedded on the inner peripheral surface of the casing main body 1 a with a certain gap with the outer peripheral surface of the rotor 45 .

In addition, the balance weight 10 is mounted on the crankshaft 9 in the following procedure. In order to ensure dynamic balance, the diameter of the balance weights 9b, 10 is usually larger than that of the inner cavity support portion 12a, so the balance weights 9b, 10 cannot pass through the inner cavity support portion 12a of the drum 11 . Therefore, the following order must be used.

That is, the drum 11 is inserted from the right side of the crankshaft 9 in FIG. 1 . Therefore, the cavity supporting part 12a of the drum 11 can be located at the opposite position to the crank 9a without passing through the balance weight 9b. Then the balance counterweight 10 is embedded from the right side of the crankshaft 9 in FIG. Then, the balance weight 10 is fixed by the key 50 and the snap ring 51 .

The operation of the helical vane type fluid compressor of this construction is as follows. That is, when the electric motor 4 is energized, the crankshaft 9 is driven to rotate integrally with the rotor 45 . The rotational force of the crankshaft 9 is transmitted to the drum 11 through the crank 9a.

That is, since the crank 9a is eccentrically arranged and freely rotatable with the cavity support portion 12a of the drum 11, the drum 11 is supported on the crank 9a. Moreover, because the Oldham coupling mechanism 13 provided between the main bearing 6 and the drum 11 limits the rotation of the drum 11, the drum 11 does not rotate when it rotates.

In addition, low-pressure refrigerant gas is sucked in from the suction pipe 17 and temporarily stored in the buffer portion 21 formed by the cylinder 5 and the drum 11 . Then it enters the compression chamber 16 on the side of the suction part A.

With the rotation of the drum 11 , the rotational contact position of the drum 11 relative to the inner peripheral surface of the cylinder 5 gradually moves in the circumferential direction, and the vane 15 enters and exits the helical groove 14 . That is, the blade 15 moves in and out in the radial direction of the drum 11 .

The refrigerant gas entering the compression chamber 16 on the side of the suction part A is sequentially transferred to the compression chamber 16 in the direction of the discharge part B along with the rotation of the drum 11 due to the helical shape of the blades 15 .

Because the above-mentioned blades 15 are set so that the distance between the suction part A and the discharge part B gradually decreases, the volume of the compression chamber 16 separated by the blades 15 gradually decreases, so the refrigerant gas is sequentially transferred to the compression chamber. When it is compressed, the compression chamber on the side closest to the discharge part B rises to a predetermined pressure and reaches a high pressure state.

The high-pressure gas is discharged from the compression chamber 16 of the discharge part B, and after filling the first space 25 , is introduced into the space on the motor 4 side through the discharge hole 24 provided in the main bearing 6 . Then, the air is introduced into and filled with the space on one side of the compression mechanism 3 through the gas guide hole 43 provided on the flange 5a of the air cylinder 5 .

Since this space is opposite the open end of the discharge pipe 18, the high-pressure gas enters the discharge pipe 18 and is led therefrom to the condenser.

Like this, because the helical vane type compression mechanism 3 of the present invention is provided with balance counterweight 9b, 10 at the both sides positions of crank 9a axially, so can obtain dynamic balance, the crank 9a that is provided makes cylinder 11 relatively fixed cylinder 5 for rotation. Moreover, because one of the balance weights 10 is formed in cooperation with the crankshaft 9, there is no need to worry about the outer diameter of the balance weight 10 and the inner diameter of the inner cavity support portion 12a of the drum 11 during assembly. Therefore, even if the balance weight 10 is large, it can be assembled, and dynamic balance can be achieved by the balance weights 9 b and 10 . Therefore, vibration during operation of the fluid compressor can be minimized.

In addition, since both the balance weights 9 b and 10 are provided between the main bearing 6 and the sub-bearing 8 , it is possible to prevent bending of the crankshaft 9 when the balance weight is provided on the motor 4 side.

Because the relative movement of the balance weight 10 relative to the crankshaft 9 in the circumferential direction is limited by the key 50, and its axial movement is also limited by the snap ring 51, it is possible to prevent the balance weight 10 from moving when the fluid compressor is running. Keep dynamic balance.

Furthermore, the present invention is not limited only to the above-mentioned embodiments. That is, although the above-mentioned embodiment has explained the helical vane type fluid compressor, it is also applicable to the rotary type fluid compressor. Also, instead of the balance weight 10, a balance weight integrated with the key may be used. Other than these, of course, other various changes can be implemented in the range which does not deviate from the gist of this invention.

According to the invention described in claim 1, dynamic balance can be achieved, and weight balance and moment balance can be ensured.

According to the invention described in Claim 2, it is possible to prevent the crankshaft from bending.

According to the invention described in claim 3, when assembling the crankshaft to the drum, even if, for example, the diameter of the connection portion between the drum and the crank is small, the crankshaft can be easily inserted.

According to the invention described in claim 4, dynamic balance can be maintained even when rotation starts.

According to the invention described in claim 5, it is possible to provide a helical vane type fluid compressor which is easy to attach the balance weight and has good assembly performance.

Claims (5)

1. A fluid compressor having a compression mechanism that compresses the compressed fluid that enters between the above-mentioned cylinder and the above-mentioned roller by rotating a roller eccentrically arranged in the cylinder; in the fluid compressor , it is characterized in that: the above-mentioned compression mechanism has a crankshaft arranged in the above-mentioned cylinder, and the crankshaft has a crank that makes the above-mentioned cylinder rotate in the above-mentioned cylinder; the crankshaft is provided with two balance weights on both sides of the above-mentioned crank in the axial direction. 2. The fluid compressor according to claim 1, wherein the crankshaft is supported by a main bearing and an auxiliary bearing, and the balance weight is arranged between the main bearing and the auxiliary bearing. 3. The fluid compressor according to claim 1, wherein one of the balance weights is integrated with the crankshaft, and the other balance weight is formed in cooperation with the crankshaft. 4. The fluid compressor according to claim 3, wherein the relative movement of the other balance weight relative to the crankshaft in the circumferential direction and the axial direction is restricted. 5. The fluid compressor according to claim 1, 2 or 3, characterized in that: the above-mentioned compression mechanism has helical grooves arranged along the circumferential surface of the above-mentioned roller and forms a gradually decreasing pitch, and has a groove that can be freely inserted into and out of The helical vane in the helical groove divides the space between the helical blade and the above-mentioned cylinder into a plurality of compression chambers whose volume gradually decreases, and enters the compression chamber on the side where the pitch of the helical groove is larger. The fluid to be compressed in the chamber is compressed while being gradually transferred to the compression chamber on the side where the pitch of the helical groove is smaller.

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