JP2000136783A - Fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid machine capable of ensuring rotating balance without giving ill effect to the number of assembling processes for a balancer and stirring lubricant, and improving in efficiency and reliability. SOLUTION: A fluid machine includes a closed container 1 with its inside under a high pressure atmosphere, a compression mechanism part 3 at the lower side and a motor part 4 at the upper side stored in the closed container and vertically connected to each other in one unit via a rotating shaft 2, and an oil reservoir part 23 formed at the inner bottom of the closed container for reserving lubricant while dipping part of the compression mechanism part at its lower side in the lubricant. The compression mechanism part sucks working fluid from the motor part side and discharges from the counter-motor-part side, with a first balancer 22 provided on the motor part side of the compression mechanism part and a second balancer 28 provided on the counter-compression- mechanism-part side of the motor part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid machine used as a helical blade type compressor, an expander, a pump, or the like which constitutes a refrigeration cycle of an air conditioner, for example.

[0002]

2. Description of the Related Art In recent years, for example, a helical blade type compressor has been proposed as a compressor constituting a refrigeration cycle of an air conditioner.

According to this type of compressor, it is possible to eliminate the poor sealing performance of a conventional reciprocating compressor or a rotary compressor, and to improve the sealing performance with a relatively simple structure to achieve efficient compression. In addition, the manufacture and assembly of parts are facilitated.

A specific configuration of a helical blade type compressor is, for example, that a eccentrically rotating roller is housed in a fixed cylinder, and a spiral groove is formed on the outer peripheral surface of the roller to engage the blade. A refrigerant gas as a working fluid is introduced into a compression chamber formed between the roller and the blade and compressed.

[0005]

By the way, in such a helical blade type fluid compressor, a crank chamber is formed in a bearing portion on both sides in order to balance the centrifugal force of a roller which performs eccentric motion with respect to a rotating shaft. And here, the balancer was housed and balanced.

However, when the balancers are housed in the two crank chambers, the assemblability of the compression mechanism is hindered, which has an adverse effect on the number of assembling steps. When the compressor is of a vertical type, the balancer provided on the lower side is located at a position where it is immersed in the lubricating oil. Therefore, this balancer agitates the lubricating oil with the rotation of the rotating shaft,
Poor refueling may occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a balancer that has no adverse effect on the number of assembling steps and accurately balances rotation without stirring lubricating oil. An object of the present invention is to provide a fluid machine which can be made highly efficient and which can improve reliability.

[0008]

According to a first aspect of the present invention, there is provided a fluid machine according to the present invention.
A lower compression mechanism portion and an upper motor portion, which are integrally connected vertically via a rotating shaft, and a lower portion of the compression mechanism portion, which is formed at an inner bottom portion of the closed container and collects lubricating oil; An oil sump part immersed in lubricating oil, wherein the compression mechanism is configured to draw working fluid from the electric motor side and discharge the fluid from the anti-motor side; A balancer is provided on each of the motor section side of the section and the anti-compression mechanism section side of the motor section.

According to a second aspect of the present invention, in the fluid machine according to the first aspect, the compression mechanism portion includes an upper crank chamber for accommodating a balancer at an upper end thereof and a lower crank chamber for accommodating a bearing member of a rotary shaft at a lower end thereof. The diameter of the upper crankcase is larger than the diameter of the lower crankcase.

According to a third aspect of the present invention, in the fluid machine according to the first aspect, the compression mechanism portion is provided between a fixed cylinder, a roller housed in the fixed cylinder and performing eccentric motion, and the roller and the cylinder. And a blade forming a plurality of compression chambers, and sealing means is provided at an end of the roller on the working fluid suction side.

According to a fourth aspect, in the fluid machine according to the third aspect, the sealing means is a ring made of a fluorine-based resin material.

According to a fifth aspect of the present invention, in the fluid machine according to the fourth aspect, the seal ring has a notch in which a part of a peripheral portion thereof is cut off.

According to a sixth aspect of the present invention, in the fluid machine according to the fourth aspect, the seal ring is elastically pressed against the roller end face by an elastic member.

According to a seventh aspect of the present invention, in the fluid machine according to the third aspect, the compression mechanism includes oil injection means for injecting the lubricating oil in the oil reservoir into the compression chamber during compression.

According to an eighth aspect of the present invention, in the fluid machine according to the seventh aspect, the oil injection means is an oil injection port provided through the peripheral surface of the cylinder.

According to a ninth aspect, in the fluid machine according to the seventh aspect, the oil injection means is an oil injection port provided to penetrate a lubricating oil immersion portion of the roller.

According to a tenth aspect, in the fluid machine according to the seventh aspect, the oil injection means injects a lubricating oil into a back side of the blade.

According to an eleventh aspect of the present invention, in the fluid machine according to the tenth aspect, the oil injection means includes an oil injection port provided through a side surface of the cylinder and an eccentric movement of a roller provided through the blade. It is characterized in that it has a hole portion which intermittently communicates with the oil injection port of the cylinder and guides the lubricating oil to the blade back surface.

According to a twelfth aspect of the present invention, in the fluid machine according to the third aspect, an oil injection port for injecting lubricating oil in an oil reservoir to the back side of the blade is provided at a portion of the compression mechanism portion immersed in lubricating oil of the roller. It is characterized by being provided.

According to a thirteenth aspect, in the fluid machine according to the third aspect, the fixed cylinder of the compression mechanism portion has a discharge passage for discharging and guiding the high-pressure working fluid discharged from the compression chamber into the closed container. Features.

According to a fourteenth aspect, in the fluid machine according to the thirteenth aspect, the discharge passage has a discharge guide end located above a lubricating oil surface of the oil reservoir.

According to a fifteenth aspect, in the fluid machine according to the thirteenth aspect, the discharge passage is a hole penetrating a thick portion provided in the cylinder.

According to a sixteenth aspect, in the fluid machine according to the thirteenth aspect, the discharge passage is a pipe attached to a cylinder.

According to a seventeenth aspect, in the fluid machine according to the thirteenth aspect, the discharge passage communicates with a discharge space including a ring-shaped step formed at a discharge side end of the cylinder.

By adopting the means for solving such a problem, the balancer can be mounted without adversely affecting the number of assembling steps, and the balance of the lubricating oil can be accurately obtained without rotating the balancer.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a so-called helical blade type compressor which is a fluid machine as a first embodiment. The helical blade type compressor includes a closed casing 1, a lower compression mechanism section 3 housed in the closed casing 1, and connected integrally vertically through a rotating shaft 2 and an upper motor section 4. Become.

At the upper end of the closed container 1, a discharged refrigerant pipe P
a is connected, and the suction refrigerant pipe Pb is connected to the side surface. A condenser, an expansion valve, and an evaporator are sequentially connected via a refrigerant pipe from the discharge refrigerant pipe Pa to the suction refrigerant pipe Pb, and these constitute, for example, a refrigeration cycle of an air conditioner.

Next, the compression mechanism 3 will be described in detail. The upper end flange of the cylinder 5 is fitted into the inner diameter of the closed container 1 and is fixed to the closed container 1 by an appropriate means. The upper end opening of the cylinder 5 is closed by a main bearing 6 that supports a middle part of the rotating shaft 2. The lower end opening of the cylinder 5 is closed by a sub-bearing 7 that supports the lower end of the rotating shaft 2.

A roller 8 is eccentrically arranged in the cylinder 5. The lower end surface of the roller 8 is supported by the sub-bearing 7 and is rotatably fitted on the peripheral surface of an eccentric crank portion 2 a provided eccentrically in the middle of the rotating shaft 2.

The amount of eccentricity of the roller 8 with respect to the center axis of the rotary shaft 2 is the same as the amount of eccentricity of the eccentric crank portion 2a, and is designed such that the outer diameter of the roller 8 is in rolling contact with the inner diameter of the cylinder 5 along the axial direction. I have.

Therefore, when the eccentric crank portion 2a rotates eccentrically with the rotation of the rotating shaft 2, the roller 8 moves eccentrically, and a part of the outer peripheral surface of the roller 8 and the cylinder 5 move.
The rolling contact portion with the inner peripheral surface moves sequentially in the circumferential direction.

A flange 8 a is integrally formed on the outer peripheral surface of the upper end of the roller 8, and engages with a concave portion 9 provided on the inner diameter of the upper end of the cylinder 5. An annular groove 10 is provided on the lower surface of the main bearing 6 facing the upper end surface of the flange 8a, and a seal ring 11 made of a fluororesin material forming a sealing means is inserted therein.

As shown in FIG.
Has a circular cross section and a circular shape in a plan view, but has a notch a in a part of the peripheral portion that is oblique to the circumferential direction, and does not maintain a perfect circular shape.

As shown in FIG. 1 again, the sub bearing 7
A rotation restricting member 12 such as an Oldham mechanism is provided between the roller 8 and the lower end of the roller 8, and controls the rotation of the roller 8 so as to make a revolving motion.

On the peripheral surface of the roller 8, a spiral groove 1 whose pitch gradually decreases from the upper end to the lower end.
3 are provided. A spiral blade 14 is fitted into the spiral groove 13 so as to be able to protrude and retract, and the outer diameter surface of the blade 14 is in close contact with the inner peripheral surface of the cylinder 5.

The roller 8 and the peripheral surface of the cylinder 5 are partitioned by the blade 14 into a plurality of continuous spaces. These spaces are referred to as compression chambers 15. The above spiral groove 1
From the setting of the pitch of 3, the volume of each compression chamber 15 gradually decreases from the upper compression chamber 15 to the lower compression chamber 15.

The cylinder 5 facing the uppermost compression chamber 15
A suction port 16 is opened in the peripheral wall, and the suction refrigerant pipe Pb penetrating through the closed casing 1 is connected to the suction port 16. Therefore, the uppermost compression chamber 15 communicates with the suction refrigerant pipe Pb.

The cylinder 5 facing the lowermost compression chamber 15
The discharge port 17 is opened in the lower peripheral wall. The discharge port 17 communicates with a discharge space 18 formed as a ring-shaped stepped portion on the inner diameter of the lower end of the cylinder 5.

A part of the outer diameter of the cylinder 5 is formed with a thick portion 5a along the axial direction, and a discharge passage 19 formed of a hole is provided here. The discharge passage 19 is open at the upper and lower end surfaces of the cylinder 5, and the lower end opening is formed at the discharge port 1.
The main bearing 6 is covered with the sub-bearing 7 while communicating with the sub-bearing 7, and the upper end opening is assembled to communicate with the discharge guide hole 20 provided in the main bearing 6.

In the roller 8, upper and lower sides of a portion rotatably fitted to the eccentric crank portion 2 a of the rotary shaft 2 are recessed, and a space is formed between the roller 8 and the rotary shaft 2.

The upper space chamber is called an upper crank chamber 21A, and the lower space chamber is called a lower crank chamber 21B.
For reasons described below, the diameter of the upper crank chamber 21A is formed larger than the diameter of the lower crank chamber 21B.

In the upper crank chamber 21A, the rotating shaft 2 is provided.
The first balancer 22 attached to the first positioner is located and accommodated. The rotation shaft pivot 7a of the sub bearing 7 is located and accommodated in the lower crank chamber 21B.

An oil reservoir 23 for collecting lubricating oil is formed in the inner bottom of the closed casing 1, and a part of the lower end of the compression mechanism 3 is immersed in the lubricating oil. Specifically, the lower side of the cylinder 5 and the roller 8 and the sub bearing 7 are immersed in the lubricating oil.

A discharge guide hole 20 provided in the uppermost end of the discharge passage 19 and the main bearing 6 is located above the lubricating oil level of the oil reservoir 23, and the first balancer 2
2 is also set so as not to be immersed in the lubricating oil of the oil reservoir 23.

The lower end surface of the rotating shaft 2 is exposed in the lubricating oil, and an oil pump 24 for sucking the lubricating oil with the rotation of the rotating shaft 2 is provided here. The rotary shaft 2 is provided with an oil supply passage 25 formed of an oil hole for guiding the lubricating oil sucked up by the oil pump 24 to each sliding portion.

The motor section 4 is opposed to a rotor 26 fitted on the rotating shaft 2 with a narrow gap on the peripheral surface of the rotor 26 and fitted on the inner peripheral surface of the closed casing 1. And a stator 27.

The second end of the rotor 26
Is mounted. This second balancer 2
8 and the first balancer 22 are set so as to achieve a dynamic balance with respect to the eccentric crank portion 2a by the total load of the first balancer 22.

To be more specific, the first balancer 22 is provided on the motor unit 4 side of the compression mechanism 3 after the compression mechanism unit 3 is located on the lower side and the motor unit 4 is located on the upper side. The second balancer 28 is provided on the motor unit 4 on the side opposite to the compression mechanism 3.

This is a helical blade type compressor constructed as described above, and energizes the electric motor unit 4 to drive the rotary shaft 2 to rotate. The rotational force of the rotating shaft 2 is equal to the eccentric crank part 2a.
To the roller 8 via

Since the rotation restricting member 12 restricts the rotation of the roller 8, the roller 8 revolves. As the roller 8 revolves, the rolling contact position with respect to the cylinder 5 gradually moves in the circumferential direction. The blade 14 moves in and out in the radial direction of the roller 8 while moving in and out of the spiral groove 13.

Through a series of these operations, low-pressure refrigerant gas is sucked from the evaporator into the uppermost compression chamber 15 through the suction refrigerant pipe Pb and the suction port 16. The rollers 8 are sequentially transferred to the compression chamber 15 on the lower side as the rollers 8 revolve.

Since the volume of each of the compression chambers 15 is gradually reduced from the upper side to the lower side, the refrigerant gas is compressed while being sequentially transferred through each of the compression chambers 15, and the lowermost compression chamber 1 is compressed.
At 5, the pressure is increased to a predetermined pressure.

The high-pressure gas in the compression chamber 15 is discharged from the discharge port 17 and is temporarily discharged from the discharge space 1 at the lower end of the cylinder.
After being filled with the liquid, the liquid is guided to the discharge passage 19 and further discharged from the discharge guide hole 20 into the closed container 1. Then, after the inside of the closed container 1 is filled, it is guided to the condenser via the discharge refrigerant pipe Pa, and a well-known refrigeration cycle operation is performed.

As described above, since the first balancer 22 and the second balancer 28 are provided at positions separated from the lubricating oil in the oil reservoir 23, the lubricating oil can be agitated even when the rotating shaft 2 rotates. Since there is no oil supply, stable oil supply to the oil supply passage 25 can be performed, and no loss due to lubricating oil stirring occurs.

Since the upper crank chamber 21A of the roller 8 accommodating the first balancer 22 is provided on the suction side where the pitch of the blades 14 is formed large, the diameter of the upper crank chamber 21A is reduced to the discharge side of the lower crank chamber. The diameter can be made larger than the diameter of 21B, and a larger space capacity can be obtained.
Therefore, the degree of freedom in design increases.

The seal ring 11 seals between the main bearing 6 and the end face of the roller 8. That is, the seal ring 11 separates the discharge pressure and the suction pressure in the sealed container 1, and controls the thrust force for pressing the roller 8 upward by this diameter, so that the seal bearing 11 moves toward the sub-bearing member 7 existing in the lubricating oil. Apply thrust force.

Since the notch a having a predetermined width is provided in the seal ring 11, the high-pressure atmosphere on the outer peripheral side is guided to the inner diameter side through the notch a, so that the outer periphery of the seal ring 11 is discharged by the discharge pressure. It can be pressed against the side to enhance the sealing performance.

The high-pressure gas discharged from the lowermost compression chamber 15 through the discharge port 17 is once filled in the discharge space 18 at the lower end of the cylinder 5. Lubricating oil does not blow up as in the case of discharging. Therefore, stable refueling is possible, and over-compression at the time of discharge can be prevented, which contributes to a reduction in operation noise due to a muffler effect.

In the above embodiment, the seal ring 1
In order to improve the sealing performance of No. 1, a notch a was provided.
It is not limited to this.

For example, as in the second embodiment shown in FIG. 3, this seal ring 11A is provided together with the seal ring 11A in an annular concave groove 10A provided in the main bearing 6.
A holding spring 30, which is an elastic member that elastically presses and presses A onto the upper end surface of the roller 8, may be inserted.

As a result, the sealing performance of the seal ring 11A is further improved. In addition, by forming the cross-sectional shape of the seal ring 11A into a substantially U-shape, the elastic force of the pressing leaf spring 30 effectively acts, and the sealing performance can be further improved.

In the above embodiment, the discharge port 17
The discharge passage 19 communicating with the cylinder 5 is provided along the thick portion 5a formed integrally with the cylinder 5, but is not limited to this.

For example, as in the third embodiment shown in FIG. 4, the cylinder 5A is formed to have a necessary minimum thickness over the entire circumference and is provided integrally with upper and lower end portions of the flange portion. Pipe 19 constituting a discharge passage extending between 5a and 5b
A is erected.

The opening at the lower end of the pipe 19A is formed so as to communicate with the discharge port 17, and the upper end is inserted into a hooking hole 20a provided in the main bearing 6. This simplifies the configuration of the cylinder 5A and the discharge passage 19A, and reduces adverse effects on cost.

The compression mechanism 3 may be provided with oil injection means as described below.

As in the fourth embodiment shown in FIG. 5, an oil injection port 35A consisting of a small hole penetrating the inner and outer diameters is provided at the lower side of the cylinder 5, and the lower compression chamber 15 The oil reservoir 23 communicates with the oil reservoir 23.

Therefore, the lubricating oil in the oil reservoir 23 is injected into the compression chamber 15 during compression. Conventionally, since lubricating oil was injected into the compression chamber on the suction side, the gas dissolved in the lubricating oil foamed in the compression chamber, which reduced the amount of gas to be originally suctioned and reduced the volumetric efficiency. By adopting such a configuration, the foamed gas does not enter the suction-side compression chamber 15, and a reduction in volumetric efficiency can be prevented. Further, since the blade 14 can be sufficiently lubricated, the reliability can be improved.

As in the fifth embodiment shown in FIG. 6, an oil injection port 35B may extend through the lower crank chamber 21B of the roller 8 and the outer periphery. Also in this case, the lubricating oil filling the lower crank chamber 21B is guided to the compression chamber 15 in the middle of compression via the oil injection port 35B. Therefore, the above-described effects can be obtained.

As in the sixth embodiment shown in FIG. 7, an oil injection port 35C penetrating the inner and outer diameters is provided at the lower side of the cylinder 5,
A hole 36 is provided in the blade 14 so as to communicate with each other depending on the rotational position of the roller 8.

From this, the lubricating oil in the oil reservoir 23 is injected into the compression chamber 15 during compression via the oil injection port 35C of the cylinder 5, and the hole 36 is formed from the oil injection port 35C by the rotation position of the roller 8. Through the bottom of the spiral groove 13.

The lubricating oil is guided to the compression chamber 15 during compression to obtain the above-described operation and effect, and the sealing performance on the end face and the side face of the blade 14 is improved, so that the efficiency is further improved.

As in the seventh embodiment shown in FIG. 8, the lower crank chamber 21B of the roller 8 and the bottom of the spiral groove 13 may be communicated by the oil injection port 35D.

In this case, the lubricating oil filling the lower crank chamber 21B is directly injected into the bottom of the spiral groove 13 via the oil injection port 35D. Therefore, the sealing performance on the end face and side face of the blade 14 is improved, and the efficiency is further improved.

In the above embodiment, a helical blade type fluid compressor is described as a fluid machine. However, the present invention is not limited to this, and may be applied to, for example, an expander or a pump.

[0075]

As described above, according to the present invention, the balancer has no adverse effect on the number of assembling steps and can accurately balance the rotation without stirring the lubricating oil, thereby improving the efficiency and reliability. And the like.

[Brief description of the drawings]

FIG. 1 is a sectional view of a helical blade type compressor as a fluid machine according to an embodiment of the present invention.

FIG. 2 is a plan view of a seal ring according to the first embodiment.

FIG. 3 is a diagram showing a relationship between a seal ring and a pressing spring according to a second embodiment.

FIG. 4 is a sectional view of a helical blade type compressor according to a third embodiment.

FIG. 5 is a sectional view of a compression mechanism of a helical blade type compressor according to a fourth embodiment.

FIG. 6 is a sectional view of a compression mechanism of a helical blade compressor according to a fifth embodiment.

FIG. 7 is a cross-sectional view of a compression mechanism of a helical blade type compressor according to a sixth embodiment.

FIG. 8 is a sectional view of a compression mechanism of a helical blade type compressor according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Closed container, 2 ... Rotating shaft, 3 ... Compression mechanism part, 4 ... Electric motor part, 23 ... Oil reservoir part, 22 ... 1st balancer, 28 ... 2nd balancer, 21A ... Upper crank chamber, 21B ... Lower part Crank chamber, 7: Sub bearing, 5: Cylinder, 8: Roller, 14: Blade, 11: Seal ring, a: Notch, 30: Pressing spring, 35A to 35D: Oil injection port 36: Hole, 19 ... discharge passage, 18 ... discharge space.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04C 29/04 F04C 29/04 B (72) Inventor Kanji Sakata 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa (72) Inventor Akira Morishima 336 Tatehara, Fuji-shi, Shizuoka Prefecture F-term in Fuji Plant (reference) 3H029 AA05 AA13 AA21 AB03 BB01 BB32 CC03 CC08 CC09 CC16 CC19 CC22 CC30 CC37 CC39 3H040 AA09 BB00 BB10 BB11 CC06 CC10 CC16 DD09 DD25 DD32

Claims (17)

[Claims] 1. A closed container having a high-pressure atmosphere inside, a lower compression mechanism unit and an upper motor unit housed in the closed container and integrally connected vertically via a rotating shaft; An oil reservoir formed at an inner bottom portion of the closed container for collecting lubricating oil and for immersing the lower part of the compression mechanism in the lubricating oil; A fluid machine that sucks in from the motor section side and discharges from the anti-motor section side, wherein a balancer is provided on each of the motor section side of the compression mechanism section and the anti-compression mechanism section side of the motor section. Fluid machinery. 2. The compression mechanism section has an upper crank chamber at an upper end thereof for accommodating the balancer, and a lower crank chamber at a lower end thereof for accommodating a bearing member of a rotating shaft. The fluid machine according to claim 1, wherein the fluid machine is formed to be larger than a diameter of the crankcase. 3. The compression mechanism section includes a fixed cylinder, a roller accommodated in the cylinder and performing an eccentric motion, and a blade provided between the roller and the cylinder to form a plurality of compression chambers. 2. The fluid machine according to claim 1, further comprising a sealing means provided at an end of the roller on the working fluid suction side. 4. The fluid machine according to claim 3, wherein said sealing means is a ring made of a fluorine-based resin material. 5. The fluid machine according to claim 4, wherein said seal ring has a cut-out portion in which a part of a peripheral portion thereof is cut off. 6. The fluid machine according to claim 4, wherein said seal ring is elastically pressed against said roller end face by an elastic member. 7. The fluid machine according to claim 3, wherein the compression mechanism includes oil injection means for injecting the lubricating oil in the oil reservoir into a compression chamber in the middle of compression. 8. The fluid machine according to claim 7, wherein said oil injection means is an oil injection port provided through a peripheral surface of said cylinder. 9. The oil injection means according to claim 7, wherein said oil injection means is an oil injection port provided to penetrate a lubricating oil immersion portion of said roller.
A fluid machine as described. 10. The fluid machine according to claim 7, wherein said oil injection means injects a lubricating oil into a back side of said blade. 11. The oil injection means is intermittently connected to an oil injection port provided through a side surface of the cylinder and an oil injection port of the cylinder provided through an eccentric motion of the roller. And a hole for communicating lubricating oil to the back surface of the blade by communicating with the blade.
A fluid machine as described. 12. An oil injection port for injecting lubricating oil in the oil reservoir to the back side of the blade is provided at a portion of the compression mechanism where the roller is immersed in lubricating oil. 4. The fluid machine according to 3. 13. The fixed cylinder of the compression mechanism section has a discharge passage for discharging and guiding a high-pressure working fluid discharged from the compression chamber into a closed container.
A fluid machine as described. 14. A fluid machine according to claim 13, wherein said discharge passage has a discharge guide end located above a lubricating oil level of said oil reservoir. 15. The fluid machine according to claim 13, wherein the discharge passage is a hole penetrating a thick portion provided in the cylinder. 16. The fluid machine according to claim 13, wherein said discharge passage is a pipe attached to said cylinder. 17. The fluid machine according to claim 13, wherein said discharge passage communicates with a discharge space formed of a ring-shaped step formed at a discharge side end of said cylinder.