JP3367109B2 - Scroll type fluid machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a pair of scrolls installed in a high-pressure dome-shaped closed casing for releasing high-pressure fluid therein so that refrigerant can be compressed in a fluid working chamber defined between spirals. The present invention relates to a scroll type fluid machine.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Publication No. 3-36160 and as shown in FIG. 7, a fixed side first scroll F and a movable side second scroll O are provided in a high-pressure dome-shaped hermetic casing D. And a fluid working chamber C in which the pressure changes from the low pressure area on the outer circumference side of the spiral to the high pressure area on the center side of the spiral between the scrolls of the scrolls F and O. An outer peripheral chamber A and a central chamber B are partitioned on the back surface, and a seal ring S using an Oldham ring that constitutes a rotation preventing mechanism of the second scroll O is provided, and the outer peripheral chamber A is provided with a low pressure communication hole L. The center side chamber B is communicated with the inside of the casing D for releasing the compressed high pressure fluid through a high pressure communication hole H provided in the housing G. In this way, low pressure is applied to the outer periphery of the back surface of the second scroll O,
By applying a high pressure to the center side, respectively, the excessive downward thrust force generated when a high pressure is applied to the entire rear surface of the second scroll O is alleviated, and the downward pressing action from the fluid working chamber C side is performed. In opposition to the force, the second scroll O is constantly pressed against the first scroll F by an appropriate thrust force, so that the air tightness in the fluid working chamber C is kept good.

[0003]

However, in the above, the center side chamber B, which is defined on the center side of the rear surface of the second scroll O, is simply communicated with the inside of the closed casing D through the high pressure communication hole H. Since only the high pressure atmosphere is provided in the center side chamber B, in order to generate the upward thrust force in the second scroll O even when the high pressure is low and the differential pressure is low, the diameter of the seal ring S is increased to increase the pressure. It is necessary to secure a relatively large area to which the pressure is applied, and on the contrary, there is a problem that the thrust force increases when the high pressure difference is high and the thrust force cannot be sufficiently relaxed.

This will be described in detail with reference to FIG. In the figure, the horizontal axis indicates high pressure pressure at equal intervals, and the vertical axis indicates a force Fc acting downward from the fluid working chamber C side and an upward back pressure Fb acting from the rear side of the second scroll O. The upward thrust force F that is the difference (Fb-Fc) between them.
s is divided at equal intervals and the value is increased in the order of a <b <c <d <e using the low pressure as a parameter. The change range of the high-pressure pressure and the low-pressure pressure is changed within an operating range that is normally assumed when the refrigerant compressor of the refrigeration system is used. Thus, as shown in the figure, the diameter of the seal ring S, that is, the high-pressure acting area, is increased in order to generate a positive thrust force even under a low differential pressure condition (point N in the figure) when the high-pressure pressure is low and the low-pressure pressure is d. If set,
When the high pressure is high and the low pressure is c, the thrust force under the high differential pressure condition (point M in the figure) increases significantly, and the contact force between the second scroll O and the first scroll F becomes excessive. However, there arises a problem that the sliding characteristics are deteriorated and the performance is lowered.

In the present invention, by devising the pressure applying structure on the back side of the second scroll, the required thrust force can be generated at the time of low differential pressure, and the thrust force becomes excessive at high differential pressure. The main object of the present invention is to provide a scroll type fluid machine capable of preventing the above and capable of generating an appropriate thrust force in the second scroll under a wide operating condition.

[0006]

In order to achieve the above main purpose, firstly, a high-pressure dome-shaped hermetic casing 9 is used.
In addition, a first scroll 1 and a second scroll 2 that orbits relative to the first scroll 1 are internally provided, and between the scroll bodies of these scrolls 1 and 2, from the low pressure region on the spiral outer circumference side to the spiral center. In a scroll type fluid machine that defines a fluid working chamber 10 in which the pressure changes toward the high pressure region on the side, the second scroll 2 is defined on the back side of the second scroll 2 with the internal space of the casing 9. The rear side chamber 4 which is divided into the outer peripheral side chamber 41 and the center side chamber 42 via the annular seal body 3 provided on the rear side of the outer peripheral side chamber 41 is provided so as to communicate the outer peripheral side chamber 41 with the low pressure region and the center side chamber 42.
In addition, the oil supply passage 6 extending from the oil pump 5 for pumping the oil stored in the casing 9 is opened, and the center side chamber 42 is communicated with the internal space of the casing 9 through the oil return passage 8 having the throttle mechanism 7. Let

Secondly, in the first means, the throttle mechanism 7 provided in the oil return passage 8 is formed by utilizing the cylindrical sliding surface of the crankshaft 93, and the sliding portion can also be lubricated. In order to do so, an oil groove 71 is opened in the cylindrical sliding surface of the crank shaft 93 that interlocks the second scroll 2, and the inlet side of this oil groove 71 is communicated with the center side chamber 42, and at the same time, the oil groove 71 The throttle mechanism 7 is configured by a path connecting the center side chamber 42 and the inlet of the oil return passage 8 with the oil passage 71 provided in the stationary member so that the outlet side communicates with the oil groove 71 in the middle. .

Thirdly, in the second means, the oil in the center side chamber 42 is returned to the oil return passage 8 in accordance with the pumping oil amount which increases or decreases in accordance with the number of revolutions, and the pressure in the center side chamber 42 is determined in accordance with the number of revolutions. In order to keep the value appropriate, an overlap structure is provided between the outlet of the oil groove 71 and the inlet of the oil return passage 8 so that the openings are intermittently aligned with each other as the crankshaft 93 rotates.

Fourthly, in each of the above-mentioned first to third means, in order to prevent the pressure in the center side chamber 42 from excessively increasing on the oil supply side and prevent the thrust force from becoming excessive, In the oil supply passage 6, a relief valve 60 that releases an abnormal increase in pressure of the pumped oil is provided.

Fifthly, in the above first means, in order to control the pressure of the center side chamber 42 on the oil return side and maintain the value appropriately, the throttle mechanism 7 is provided with an opening area corresponding to an increase in the pressure of the center side chamber 42. Is constituted by a variable throttle valve 72 that expands.

[0011]

By the first means, the pressure in the central chamber 42 becomes a value obtained by adding the high pressure and the pressure boosted by the oil pump 5. In this case, unlike the high pressure that fluctuates depending on the operating conditions, the pressure boosted by the oil pump 5 is kept almost constant at all times, and in addition to the high pressure that fluctuates depending on the operating conditions, the back pressure of the second scroll 2 is almost constant. The boosted pressure of the oil pump 5, which is maintained at a constant value, acts in addition.
Therefore, even if the diameter of the annular seal body 3 is reduced to reduce the working area of the center side rear surface of the second scroll 2 facing the center side chamber 42, an upward positive thrust force is generated under a low differential pressure condition. Therefore, the second scroll 2 can be properly pressed against the first scroll 1. On the other hand, under a high differential pressure condition, it is possible to prevent the thrust force from becoming excessively large by the reduction of the acting area of the center side rear surface in contact with the center side chamber 42 and the reduction of the high pressure application area.

By the second means, the oil flowing in the oil groove 71 can also be used to lubricate the cylindrical sliding surface of the crankshaft 93.

By the third means, the oil flowing in the oil groove 71 is intermittently transferred to the oil return passage 8 as the crankshaft 93 rotates, and the pumping oil amount in the center side chamber 42 increases and decreases according to the rotation speed. The oil can be returned according to the above, and the pressure in the center side chamber 42 can be appropriately maintained according to the number of rotations.

By the fourth means, when an abnormal pressure rise occurs in the path connecting the oil supply passage 6 and the center side chamber 42, this pressure can be released to the inside of the closed casing 9 through the relief valve 60, It is possible to prevent the thrust force acting on the back surface of the second scroll 2 from becoming excessive.

By the fifth means, the opening area of the variable throttle valve 72 is changed according to the pressure of the center side chamber 42, so that the pressure value of the center side chamber 42 can be maintained properly and the thrust force can be properly adjusted. Can be held.

[0016]

1 and 2 show a scroll type fluid machine used as a refrigerant compressor in a refrigerating machine, in which an end plate 1 is provided on an upper portion of a high pressure dome type closed casing 9.
1, a first scroll 1 on the fixed side in which a spiral body 12 and an outer peripheral wall 13 continuous with the spiral body 12 are projectingly provided;
And a rear side boss portion 23 projecting from the inside, and a movable side second scroll 2 that revolves with respect to the first scroll 1 in a state where its rotation is blocked by an Oldham ring 24, and At the bottom, the stator 92a and the rotor 9
An eccentric pin portion 93 that is equipped with 2b and fits into the boss portion 23
The motor 92 in which a crankshaft 93 having d is directly connected is installed. A fluid working chamber 10 is defined between the spiral bodies 12, 22 in which the pressure changes from a low pressure area on the outer circumference of the spiral opening the suction pipe 94 to a high pressure area on the central side of the discharge spiral opening the discharge hole 95. Then, the high-pressure fluid after being compressed in the working chamber 10 is once released into the closed casing 9 and then taken out from the discharge pipe 96 to the outside.

With the above construction, the seal ring 31 is formed on the back side of the second scroll 2 so as to define the internal space of the casing 9 through the upper housing 97 and to be arranged on the back side of the second scroll 2. An outer peripheral side chamber 41 and a center side chamber 4 via an annular seal body 3 including an urging O-ring 32.
A back room 4 is provided which is divided into two parts. And the outer chamber 4
1 is communicated with the low pressure region on the spiral outer circumference side through the low pressure communication hole 14, and the center side chamber 42 is penetratingly formed in the crankshaft 93 and the oil in the oil sump 99 provided below the lower housing 98 is pumped up. An oil supply passage 6 extending from the trochoid type oil pump 5 is opened via a communication groove 6a which is cut out on the outer periphery of the eccentric pin portion 93d. Further, the center side chamber 42 is provided with a throttle mechanism 7 described below, and is communicated with the oil sump 99 via an oil return passage 8 formed of an oil return hole 81 provided in the upper housing 97 and an external oil return pipe 82.

The throttle mechanism 7 may be constructed by using an orifice, a capillary tube, or the like, but this is constructed from a D-shaped cut portion on the cylindrical sliding surface 93a of the crankshaft 93 facing the upper bearing metal 97a. The oil groove 71 is formed so that the upper inlet portion of the oil groove 71 is opened to the bottom portion of the center side chamber 42, and the outlet side of the oil groove 71 is provided through the lateral hole 81a provided in the upper bearing metal 97a to the oil return hole. 81, and the oil groove 71 is interposed in the middle part so that the central chamber 4
The throttling mechanism 7 is constituted by a path connecting 2 and the inlet of the oil return passage 8. Further, between the outlet of the oil groove 71 and the lateral hole 81a serving as the inlet of the oil return passage 8, the openings are intermittently matched at a rate of once per rotation as the crankshaft 93 rotates. It has an overlapping structure.

Further, the oil supply passage 6 located under the crankshaft 93 is provided with a radial opening hole 61, and a plate valve 62 for releasing an abnormal pressure rise of the pumping oil and its valve retainer 63 are provided in the opening. Cantilever type relief valve 60 with and
Is intervening.

Thus, with the above structure, the central chamber 4
2 is a pressure obtained by adding the high pressure and the pressure boosted by the oil pump 5, and in this case, the pressure boosted by the oil pump 5 is always maintained at a substantially constant value regardless of the value of the high pressure that fluctuates depending on the operating conditions. Therefore, as shown in FIG. 3, on the back surface of the second scroll 2, in addition to the high-pressure pressure, an increased pressure by the oil pump 5 of, for example, about 5 kgf / square centimeter, which is maintained at a substantially constant value, acts in addition. Therefore, the diameter of the annular seal body 3 is reduced by about 20% as compared with the conventional one shown in FIGS. 7 and 8, and the action area of the center side rear surface of the second scroll 2 facing the center side chamber 42 is reduced. Even under a low differential pressure condition (point N in the figure), an upward positive thrust force having an appropriate magnitude can be generated, and the second scroll 2 is replaced by the first scroll 1
In addition, it is possible to properly press the roller against the high pressure differential condition (point M in the figure), and the thrusting force becomes excessive due to the reduction of the operating area in contact with the center side chamber 42 and the reduction of the high pressure applied area. It can be prevented. The characteristic diagram of FIG. 3 is divided on the same scale as that of FIG. 8, and the low pressure values a, b, c, d, and e used as parameters are also unified.

Further, in the above, since the throttle mechanism 7 is constituted by using the oil groove 71 which is opened in the cylindrical sliding surface of the crank shaft 93, the sliding portion can be also used for lubrication. Further, in the above-described structure, the gap between the outlet of the oil groove 71 and the inlet of the oil return passage 8 has an overlap structure in which the openings are intermittently aligned with each other as the crankshaft 93 rotates. For example, when the motor 92 is set to a variable speed by an inverter control or the like, the oil in the center chamber 42 whose pumping oil amount increases or decreases depending on the rotation speed of the motor 92 is returned in accordance with the oil amount.
Therefore, the pressure in the center side chamber 42 can be appropriately maintained according to the rotation speed. However, the oil groove 71 and the oil return passage 8 may be provided without overlapping as shown in FIG. 4, and even in this case, lubrication of the sliding portion of the crankshaft 93 can be ensured.

Further, in the above, since the relief valve 60 is provided, it is possible to prevent the pressure in the central chamber 42 from excessively increasing due to various causes such as an increase in the number of rotations and clogging of the throttle mechanism 7. It can be suppressed, and the thrust force can be prevented from abnormally increasing.

By the way, in the above embodiment, the throttle mechanism 7 is constituted by using the oil groove 71. However, as shown in FIG. 5, the oil return hole 81 provided in the upper housing 97 is opened in the center side chamber 42. , Inside the oil return hole 81, the aperture opening 7
2a, a valve body 72b facing this, and a biasing body 72c that biases the valve body 72b toward the closing side, and the opening area of the throttle opening 72a increases as the pressure in the central chamber 42 increases. 72 may be used, and in this case, the pressure of the center side chamber 42 can be controlled on the oil return side to maintain the pressure value appropriately, and the thrust force can be appropriately maintained.

Further, in the above embodiments, the oil return passage 8 is
Although the oil return hole 81 provided in the upper housing 97 and the external oil return pipe 82 are used to directly open to the oil sump 99, as shown in FIG. A second oil return hole 8 comprising an oil hole 83 and an oil injection passage which is continuously provided in the first scroll 1 and has an outlet opening to the fluid working chamber 10 in the intermediate pressure region.
4 may be used to communicate with the internal space of the closed casing 9 from the discharge hole 95 via the inside of the fluid working chamber 10.

In the structure shown in FIG. 6, a convex boss portion 23 is provided on the rear surface of the second scroll 2 and the boss portion 23 is formed of an eccentric hole which is opened at the upper end of the crankshaft 93. The oil that is fitted to the eccentric pin portion 93d and that is pumped into the oil supply passage 6 is delivered to the communication hole 6c provided in the boss portion 23 of the second scroll 2 through the seal ring 6b that is interposed in the connection portion, and this communication hole The central chamber 42 is opened via 6c. Further, the oil groove 7 that constitutes the throttle mechanism 7
Reference numeral 1 denotes an inner peripheral oil groove 71a provided in a contact portion between the boss portion 23 and the eccentric pin portion 93d, and a lower portion thereof communicates with the inner peripheral oil groove 71a through a communication hole 70 to form an upper bearing. The outer peripheral oil groove 71b is in contact with the metal 97a.
The inlet side of the oil return passage 8 is opened to the lower side of the outer peripheral oil groove 71b. Further, the oil pump 5 is of a centrifugal type.

[0026]

As described above, according to the first aspect of the invention, since the high pressure and the pressure boosted by the oil pump 5 act on the center side of the rear surface of the second scroll 2, the diameter of the annular seal body 3 is reduced. Even if the action area on the rear center side of the second scroll 2 is reduced to be small, the upward thrust force can be generated under the low differential pressure condition, and the second scroll 2 can be appropriately pressed against the first scroll 1. At the same time, under a high differential pressure condition, it is possible to prevent the thrust force from becoming excessive due to the reduction of the high-pressure applied area, and the sliding characteristic between the first scroll 1 and the second scroll 2 can be prevented. Can be improved.

According to the second aspect of the invention, the oil flowing in the oil groove 71 can also be used to lubricate the cylindrical sliding surface of the crankshaft 93.

According to the third aspect of the invention, the overlap structure between the oil groove 71 and the oil return passage 8 allows the pressure in the center side chamber 42 to be appropriately maintained according to the number of revolutions.

According to the fourth aspect of the invention, the relief valve 60 can prevent the thrust force acting on the back surface of the second scroll 2 from abnormally rising.

According to the fifth aspect of the present invention, the variable throttle valve 72 can properly maintain the pressure value of the center side chamber 42 and also properly maintain the thrust force.

[Brief description of drawings]

FIG. 1 is an upper sectional view showing a first embodiment of a scroll type fluid machine according to the present invention.

FIG. 2 is a bottom sectional view of the same.

FIG. 3 is a characteristic diagram illustrating the same operation.

FIG. 4 is a sectional view of a main part showing the second embodiment.

FIG. 5 is a cross-sectional view of a main part showing the third embodiment.

FIG. 6 is a sectional view showing the fourth embodiment.

FIG. 7 is a sectional view of a conventional scroll type fluid machine.

FIG. 8 is a characteristic diagram illustrating a conventional problem.

[Explanation of symbols]

1 first scroll 2 second scroll 3 annular seal body 4 back room 5 oil pump 6 oil supply passage 7 Aperture mechanism 8 oil return passage 9 closed casing 10 Fluid working chamber 41 Outer chamber 42 Center side chamber 60 relief valve 71 oil ditch 72 Variable throttle valve 93 crankshaft

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Mikio Kajiwara, 3-12 Tsukikoshinmachi, Sakai City, Osaka Prefecture Daikin Industry Co., Ltd. Sakai Plant's seaside factory (56) Reference JP 62-139991 (JP, A) JP-A-2-173377 (JP, A) JP-A-59-49386 (JP, A) JP-A-56-165788 (JP, A) JP-A-61-169686 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04C 18/00-18/077

Claims (5)

(57) [Claims] 1. A high-pressure dome-shaped hermetic casing 9 is internally provided with a first scroll 1 and a second scroll 2 which orbits relative to the first scroll 1, and a scroll body of these scrolls 1 and 2. In the scroll type fluid machine, which defines a fluid working chamber 10 in which the pressure changes from a low pressure area on the spiral outer circumference side to a high pressure area on the spiral center side, a casing 9 is provided on the back side of the second scroll 2. A rear chamber 4 is provided which is partitioned from the inner space and is divided into an outer peripheral chamber 41 and a central chamber 42 via an annular seal body 3 provided on the rear face side of the second scroll 2, and the outer peripheral chamber 41 is placed in a low pressure region. While communicating with each other, an oil supply passage 6 extending from an oil pump 5 that pumps up oil stored in the casing 9 is opened in the center side chamber 42, while the center side chamber 42 has a throttle mechanism 7. Wherein through the oil passage 8 casing 9
A scroll type fluid machine characterized by being communicated with the internal space of the. 2. An oil groove 71 is opened in a cylindrical sliding surface of a crank shaft 93 for interlocking the second scroll 2, and the oil groove 71 is formed.
Of the center side chamber 4 by communicating the inlet side of the oil groove 71 with the center side chamber 42 and the outlet side of the oil groove 71 with the oil return passage 8 provided in the stationary member.
2 is connected to the inlet portion of the oil return passage 8 by a throttle mechanism 7
The scroll type fluid machine according to claim 1, which is configured as follows. 3. The overlap structure between the outlet of the oil groove 71 and the inlet of the oil return passage 8 is such that the openings are intermittently aligned with each other as the crankshaft 93 rotates.
The scroll-type fluid machine described. 4. The scroll type fluid machine according to claim 1, 2 or 3, wherein a relief valve 60 is provided in the oil supply passage 6 to release an abnormal pressure rise of the pumping oil. 5. The scroll type fluid machine according to claim 1, wherein the throttle mechanism 7 comprises a variable throttle valve 72 whose opening area increases as the pressure in the central chamber 42 increases.