JPH0615802B2 - Scroll type fluid machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll type fluid machine, more specifically, a fixed scroll having a spiral wrap and a revolution scroll, and a crankshaft on the back surface of the revolution scroll. The present invention relates to a scroll type fluid machine in which a bearing sleeve for receiving the eccentric shaft portion is provided, and the eccentric shaft portion is rotatably fitted in the bearing sleeve.

(Prior Art) A scroll type fluid machine configured as described above is disclosed in Japanese Patent Laid-Open No.
It is also described in Japanese Patent Publication No. 5-35152 and is already known.

By the way, as shown schematically in FIG. 4, this one has a fixed scroll (50) and an orbiting scroll (51) which are opposed to each other and assembled to form a closed space (52) between the scrolls (50) and (51). I do it as I do,
In order to ensure the airtightness of the hermetically sealed space (52), conventionally, the dimensions of the scrolls (50) (51) are appropriately set, and the front-packed scroll (51) is assembled by assembling.
A proper contact pressing force in the radial direction is applied between the wraps (53) and (54) of the (50).

Incidentally, (55) is a bearing cylinder provided on the rear surface of the revolution scroll (51), and the crankshaft (5
The eccentric shaft portion (57) of 6) is fitted.

(Problems to be Solved by the Invention) However, setting the contact pressing force to a desired value at the time of assembling the scrolls (50) (51) makes it possible to manufacture the scrolls (50) (51). It was extremely difficult due to errors and assembly errors.

Further, even if the contact pressing force during operation is made constant by the above-mentioned assembly of the contact pressing force, the internal pressure of the closed space (52) acts so as to reduce the contact pressing force. , If this internal pressure fluctuates due to the load,
Since the contact pressing force changes, for example, when the load becomes large, the contact pressing force is insufficient and the sealing property of the closed space (52) is deteriorated, while when the load is small, The contact pressing force is too large to secure the sealing property, but the wrap (53) (5
There was a problem that unnecessarily large power loss occurred between 4).

(Means for Solving Problems) Accordingly, in the present invention, the cam means is interposed between the bearing cylinder of the revolution scroll and the eccentric shaft portion, and the revolution scroll is centered on the eccentric shaft portion. The contact pushing force can be set by using the pushing force resulting from the centrifugal force acting on the orbiting scroll and the internal pressure of the closed space so that the contact pushing force can be rocked. A scroll having a fixed scroll having a spiral wrap and an orbiting scroll, the orbiting scroll having a bearing tube for receiving an eccentric shaft portion of a crankshaft, and the bearing tube having the eccentric shaft portion rotatably fitted therein. Type fluid machine, the shaft center (Os) of the bearing tube is replaced with the shaft center (Or) of the crankshaft.
And a first line segment (OsOr) that is deviated from the shaft center (Oc) of the eccentric shaft portion and connects the shaft center (Or) of the crankshaft and the shaft center (Os) of the bearing cylinder, A second line segment connecting the shaft center (Os) of the bearing cylinder and the shaft center (Oc) of the eccentric shaft portion is defined as (OsOc), and further, these line segments (Os)
An angle formed by Or) (OsOc), and an angle formed in the same direction as the rotation direction of the crankshaft from the second line segment (OsOc) to the first line segment (OsOr) is (θ). At this time, a cam means is interposed between the eccentric shaft portion and the bearing sleeve, which makes the angle (θ) variable within a range of 270 ° <θ <360 °.

(Operation) With the configuration as described above, the centrifugal force acting on the orbiting scroll and the pressing force resulting from the internal pressure of the closed space formed by the fixed scroll and the orbiting scroll are accompanied by the operation of the fluid machine. The orbiting scroll is swung about the eccentric shaft in the direction in which the wrap of the scroll is pressed against the wrap of the fixed scroll, a contact pressing force acts between these wraps, and this contact pressing force is It can be determined by setting the angle (θ), and the contact pushing force increases / decreases in accordance with the increase / decrease in the internal pressure of the sealed space, and as a result, the sealing property between the laps is always kept good. is there.

(Example) Hereinafter, the Example of this invention is described based on drawing.

The one shown in FIG. 3 is the one in which the present invention is applied to a compressor of a refrigerating apparatus, which has a spiral wrap (1a).
A compression element (3) consisting of a fixed scroll (1) having (2a) and an orbiting scroll (2) is formed, and the compression element (3) and a motor (4) for driving the compression element (3) are formed. It is fixed to the frame (A) and is installed in the casing (5).

The eccentric shaft portion (7) of the crankshaft (6) extending from the motor (4) on the back side of the orbiting scroll (2).
A cylindrical bearing tube (8) that axially supports is formed, and the eccentric shaft portion (7) is fitted into the bearing tube (8), while the rear side of the revolution scroll (2) and the frame (A ) Is provided with a rotation preventing mechanism which is composed of a slide body (9) and a slide body receiver (10) and prevents the scroll (2) from rotating.

Further, a suction pipe (11) is connected to the casing (5) to reduce the pressure inside the casing (5) and the suction port (12) provided in the compression element (3) inside the casing (5). On the other hand, a discharge pipe (14) is connected to a discharge port (13) also provided in the compression element (3) so that the discharge port (13) is opened outside the casing (5).

Thus, the orbiting scroll (2) revolves with respect to the fixed scroll (1) by driving the motor (4), whereby the compression element (3) sucks low-pressure refrigerant from the suction port (12), The elegant refrigerant is compressed and the high-pressure refrigerant is discharged to the outside of the casing (5) through the discharge pipe (14).

In FIG. 3, (15) and (16) are bearings for supporting the crankshaft (6) on the frame (A), and (17) is the orbiting scroll (2) in the thrust direction. In, a thrust bearing for supporting the frame (A) and (18) are bearing metals.

In the scroll type fluid machine configured as described above, as schematically shown in FIGS. 1 and 2, a cam ring () is provided between the bearing tube (8) and the eccentric shaft portion (7) of the crankshaft (6). The cam tube) (71), and the bearing tube (8)
The shaft center (Os) of the crankshaft (6)
r) and the axial center (Oc) of the eccentric shaft portion (7). In FIG. 2, (ω) indicates the rotation direction of the crankshaft (6).

In the following, in explaining this configuration in detail, first,
An evaporator or a condenser (neither of which is shown) is connected to the fluid machine, and the forces acting on the revolution scroll (2) and the forces acting on the revolution scroll (2) in a state where the fluid machine is in a steady operation. The balance of moments regarding the axis (Oc) of the eccentric shaft portion (7) will be described.

The pressing force acting on the revolution scroll (2) will be described with reference to FIG. 2. The force acting on the revolution scroll (2) is: (Fp) is the wrap (2) of the revolution scroll (2)
b) the contact pressing force received by the revolution scroll (2) based on the contact between the fixed scroll (1) and the wrap (1a), (Fw) is the revolution scroll (2) when the crankshaft (6) Centrifugal force acting on the orbiting scroll (2) by rotating around, (Fr) is the internal pressure of the closed space (compression chamber) formed by the fixed scroll (1) and the orbiting scroll (2). Due to this, the pressing force acting on the orbiting scroll (2) is exerted on the line connecting the axis (Or) of the crankshaft (6) and the axis (Os) s of the bearing cylinder (8). Force (hereinafter, referred to as first pressing force), (Fd) is a component force (hereinafter, second pressing force) of the pressing force resulting from the internal pressure of the enclosed space in a direction orthogonal to the first pressing force (Fr). It is called pressure).

Then, on a virtual plane orthogonal to the axis (Or) of the crankshaft (6), the axis (Or) of the crankshaft (6) and the axis (Os) of the bearing tube (8) are formed. And a second line segment connecting the shaft center (Os) of the bearing tube (8) and the shaft center (Oc) of the eccentric shaft portion (7) is (OsOc), Furthermore, these line segments (Os
Or) (OsOc), which is an angle formed by the second line segment (OsOc) and the first line segment (OsOr) in the same direction as the rotation direction of the crankshaft (6). ), The following relationship holds for the above-mentioned pressing force (pressing force) from the balance of moments about the axis (Oc) of the eccentric shaft portion (7), that is, Fp = Fw-Fdcotθ -Fr Fp = Fw + Fdcotα-Fr Here, θ = 2π-α ... The centrifugal force (Fw) is determined by the set rotation speed of the motor (4), and the internal pressure of the closed space. Is determined by the design load during normal operation, so the first pressure (Fr) and the second pressing force (Fd) are also determined by the design load. Then, under these given pressing force (Fw) (Fr) (Fd) conditions,
The contact pressing force (Fp) during normal operation can be easily set to a desired value by appropriately setting the angle (θ or α).

Since the first pressing force (Fr) is considerably smaller than the centrifugal force (Fw) and the second pressing force (Fd), the first pressing force (Fr) will be omitted in the following description.

Then, when the revolving scroll (2) is assembled to the fixed scroll (1), it is interposed between the bearing cylinder (8) of the revolving scroll (2) and the eccentric shaft portion (7). By appropriately selecting the cam ring (71), the angle (θ) is larger than 270 ° and smaller than 360 °, that is, the angle (α) is larger than 0 ° and 9
The contact pressing force (Fp) in the normal operation is set to a desired value within a range smaller than 0 °.

The operation of the scroll type fluid machine configured as described above will be described.

When the motor (4) is driven, the orbiting scroll (2) revolves, and the compression element (3) is compressed as described above.

Then, the centrifugal force (Fw) accompanying the revolution (rotation) and the second pressing force (Fd) caused by the internal pressure of the compression element (3) act on the orbiting scroll (2). Further, since the cam ring (71) is interposed between the eccentric shaft portion (7) and the bearing tube (8), each force (Fw) (Fd) is applied to the revolution scroll (2). Causes a rotational moment about the eccentric shaft portion (7), the wrap (2a) of the revolution scroll (2) is pressed against the wrap (1a) of the fixed scroll (1), and each wrap (1a) ( A contact pressing force (Fp) is generated between 2a).

Moreover, this contact pressing force (Fp) can be easily set by setting the angle (θ or α), as is clear from the above equation.

Furthermore, when the load of this fluid machine fluctuates and the internal pressure of the compression element (3) increases or decreases, the cam ring (7)
According to 1), the angle (θ) is larger than 270 ° and smaller than 360 °, that is, the angle (α) is larger than 0 ° and smaller than 90 °, and cotθ is negative, that is, cotα is positive. Since it is set so that
As is clear from the above equation, the contact pressing force (Fp) increases / decreases in accordance with the increase / decrease in the second pressing force (Fd) accompanying the increase / decrease in the internal pressure. That is, when the internal pressure of the compression element (3) becomes large, the contact pressing force (Fd) increases accordingly, and the sealing performance of the closed space in the compression element (3) can be secured. When the internal pressure becomes small, the contact pressing force (Fd) also decreases accordingly, and it is possible to prevent an unnecessarily large sliding resistance from occurring between the laps (1a) and (2a). Of.

(Effect of the Invention) As described above, according to the present invention, the cam means (cam ring) (71) is interposed between the eccentric shaft portion (7) and the bearing tube (8), and the angle (θ) is set. Since it is larger than 270 ° and smaller than 360 °, each wrap (1a) of the fixed scroll (1) and the revolution scroll (2)
The contact pressing force (Fp) of (2a) can be easily set to a desired value without further reducing manufacturing tolerances and assembly errors.

In addition, since the contact pushing force (Fp) can be increased or decreased according to the load change, the wraps (1a) (2a) can be maintained while the sealing property of the closed space is kept good against the load change. It is possible to prevent an unnecessarily large sliding resistance between the two) and a power loss.

[Brief description of drawings]

1 is a schematic vertical sectional view of an essential part of an embodiment of the present invention, FIG. 2 is a schematic plan sectional view of an essential part of the embodiment, FIG. 3 is a vertical sectional view of the same, and FIG. 4 is a conventional example. It is an explanatory view shown. (1) …… Fixed scroll (2) …… Orbital scroll (6) …… Crank shaft (7) …… Eccentric shaft (8) …… Bearing tube (71) …… Cam ring (cam means) (1a) ( 2a) ... Lap (Os) (Or) (Oc) ... Shaft center (θ) ... Angle

Claims (1)

[Claims] 1. A spiral wrap (1a) (2a)
A fixed scroll (1) and an orbiting scroll (2), and a bearing cylinder (8) for receiving the eccentric shaft portion (7) of the crankshaft (6) on the rear surface of the orbiting scroll (2),
In a scroll type fluid machine in which the eccentric shaft portion (7) is rotatably fitted in the bearing cylinder (8), the shaft center (Os) of the bearing cylinder (8) is set to the shaft center of the crankshaft (6). (Or) and the shaft center (Oc) of the eccentric shaft portion (7), and the shaft center (O) of the crankshaft (6).
r) and a first line segment connecting the shaft center (Os) of the bearing cylinder (8) (OsOr), and the shaft center (Os) of the bearing cylinder (8) and the shaft center of the eccentric shaft portion (7). The second line segment that connects (Oc) is defined as (OsOc), and these line segments (OsOr) (O
sOc), which is the angle formed by the second line segment (OsOc
When the angle formed in the same direction as the rotation direction of the crankshaft (6) from (c) toward the first line segment (OsOr) is (θ), the eccentric shaft portion (7) and the bearing tube (8) ), And a cam means for changing the angle (θ) in the range of 270 ° <θ <360 ° is interposed.