JPH0612043B2 - 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 and a revolving scroll each having a spiral wrap, and a shaft protruding from the rear surface of the revolving scroll. The present invention relates to a scroll type fluid machine in which a bearing hole is formed in an eccentric shaft portion of a crankshaft, and the shaft is inserted into the bearing hole to connect the revolution scroll and the crankshaft.

(Prior Art) A scroll type fluid machine configured as described above is also described in Japanese Patent Application Laid-Open No. 58-79468 and is already known.

By the way, as shown schematically in FIG. 5, the fixed scroll (50) and the revolving scroll (51) are assembled so that they face each other, and a closed space (52) is formed between these scrolls (50) (51). Although it is done as much as possible, in order to ensure the airtightness of this closed space (52),
Conventionally, the dimensions of the scrolls (50) and (51) are appropriately set, and the scrolls (5
1) Appropriate radial contact pressing force acts between the wraps (53) and (54) of (50).

Reference numeral (55) is a shaft provided on the rear surface of the revolution scroll (51), and the shaft (55) is inserted into a bearing hole (58) formed in the eccentric shaft portion (57) of the crankshaft (56). The orbiting scroll (51) and the crankshaft (56) are connected together.

(Problems to be Solved by the Present Invention) However, setting the contact pressing force to a desired value at the time of assembling each of the scrolls (50) and (51) is performed by setting each of the scrolls (50) and (51). It was extremely difficult due to manufacturing 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 pushing force changes, for example, when the load becomes large, the contact pushing force is insufficient and the sealing property of the closed space (52) is deteriorated. On the other hand, since the contact pushing force is too large and the sealing property is secured, the wrap (53) (5
There was a problem that an unnecessarily large power loss occurred between 4).

(Means for Solving Problems) Therefore, according to the present invention, cam means is provided between the shaft of the revolution scroll and the bearing hole of the eccentric shaft portion, and the revolution scroll has the shaft center of the bearing hole. The contact pressure can be set by utilizing the centrifugal force acting on the orbiting scroll and the pressure resulting from the internal pressure of the sealed space. The structure includes a fixed scroll and a revolution scroll, each of which has a spiral wrap, a shaft protruding from a rear surface of the revolution scroll, a bearing shaft hole formed in an eccentric portion of the crankshaft, and the bearing hole formed in the bearing hole. In a scroll type fluid machine in which a shaft is inserted to connect the revolution scroll and the crankshaft, the shaft center (Os) of the revolution scroll is set to the shaft center (Or) of the crankshaft. ) And a first line segment that deviates from the shaft center (Oc) of the bearing hole in the eccentric shaft portion and connects the shaft center (Or) of the crankshaft and the shaft center (Os) of the revolution scroll shaft. (OsO
r), the axis of the shaft (Os) and the axis of the bearing hole (O)
(OsOc) is the second line segment that connects with c), and is the angle formed by these line segments (OsOr) (OsOc),
From the second line segment (OsOc) to the first line segment (OsOc)
r), when the angle formed in the same direction as the rotation direction of the crankshaft is (θ), the angle (θ) between the bearing hole and the shaft of the revolution scroll is 0> cotθ The cam means that is variable within the range is provided.

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

(Examples) Examples of the present invention will be described below with reference to the drawings.

The one shown in FIG. 3 is one in which the present invention is applied to a compressor of a refrigeration system, and each has a spiral wrap (1
a) A compression element (3) comprising 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).
And are fixed to the frame (A) and are installed in the casing (5).

The shaft (8) is provided on the rear side of the orbiting scroll (2).
On the other hand, an eccentric shaft portion (7) having a cylindrical outer surface concentric with the crank shaft (6) is provided on the crank shaft (6) extending from the motor (4), and the eccentric shaft portion (7) A bearing hole (7) having an eccentric shaft center with respect to the crank shaft (6).
1) is formed, and the shaft (8) of the revolution scroll (2) is inserted into the bearing hole (71) so that the revolution scroll (2) and the crankshaft (6) are coupled together. There is.

An Oldham ring (9) is provided between the rear side of the revolving scroll (2) and the frame (A) so as to prevent 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, the discharge port (13) is also connected to the discharge port (13) provided in the compression element (3), and 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 refrigerant is compressed to discharge the high-pressure refrigerant to the outside of the casing (5) through the discharge pipe (14).

In FIG. 3, (15) and (16) are radial 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 (cam means) is provided between the shaft (8) of the revolution scroll (2) and the bearing hole (71) of the eccentric shaft portion (7).
The shaft center (Os) of the shaft (8) is inserted into the shaft center (Or) of the crankshaft (6) and the bearing hole (71) of the eccentric shaft portion (7) through (K). It is deviated from the axis (Oc). 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 the moment regarding the shaft center (Oc) of the bearing hole (71) in 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)
a) the contact pushing force received by the orbiting scroll (2) based on the contact between the orbiting scroll (1a) and the wrap (1a) of the fixed scroll (1), (Fw) indicates that the orbiting scroll (2) rotates around the crankshaft (6) Centrifugal force acting on the orbiting scroll (2) by rotating., (Fr) is caused by the internal pressure of the closed space (compression chamber) formed by the fixed scroll (1) and the orbiting scroll (2). Is a pressing force acting on the orbiting scroll (2), and is a component force acting on a line connecting the axis (Or) of the crankshaft (6) and the axis (Os) of the shaft (8) (hereinafter , (Fd) is the component force of the pressing force resulting from the internal pressure of the closed space in the direction orthogonal to the first pressing force (Fr) (hereinafter referred to as the second pressing force). Is.

Then, on a virtual plane orthogonal to the axis (Or) of the crankshaft (6), the axis (Or) of the crankshaft (6) and the axis (8) of the revolution scroll (2). The first line segment connecting the core (Os) is (OsOr), the axis (Os) of the shaft (8) and the axis (O) of the bearing hole (71).
(OsOc) is the second line segment that connects the line c) and the angle formed by these line segments (OsOr) (OsOc), and is directed from the second line segment (OsOc) to the first line segment (OsOr). And an angle (θ) formed in the same direction as the rotation direction of the crankshaft (6), the moment balance around the shaft center (Oc) of the bearing hole (71) in the eccentric shaft part (7) The following relationship is established for the pressing force (pressing force) described above, that is, Fp = Fw-Fdcotθ-Fr Fp = Fw + Fdcotα-Fr, where θ = 2π-α ... The centrifugal force (Fw) is the motor. (4) is determined by the set rotation speed, and the internal pressure of the closed space is determined by the design load during normal operation. Therefore, the first pressing force (Fr) and the second pressing force ( Fd) also depends on the design load. Are those determined Te. Then, under these applied pressing force (Fw) (Fr) (Fd) conditions, the contact pressing force (Fp) during normal operation can be easily set by appropriately setting the angle (θ or α). It can be as desired.

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 assembling the orbiting scroll (2) to the fixed scroll (1), it is interposed between the shaft (8) of the orbiting scroll (2) and the bearing hole (71) in the eccentric shaft portion (7). The cam ring (K) to be mounted is appropriately selected so that cotθ is negative with respect to the angle (θ), that is, cotα is positive with respect to the angle (α), and the contact pushing force during normal operation is increased. The force (Fp) is set to a desired value. Specifically, the first
As shown in the figure, the angle (θ) is larger than 270 ° and 3
Less than 60 °, that is, the angle (α) is greater than 0 ° and 9
It may be set in a range smaller than 0 °, or, as shown in FIG. 4, the angle (θ) is larger than 90 ° and smaller than 180 °, that is, the angle (α) is larger than 180 °. E 27
It may be set in 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 revolution scroll (2) revolves, and the compression element (3) as described above.
A compressive action occurs in the.

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). Since the cam ring (K) is interposed between the bearing hole (71) in the eccentric shaft portion (7) and the shaft (8), each of the forces ( F
w) and (Fd) generate a rotational moment about the shaft center of the bearing hole (71) in the eccentric shaft portion (7),
The wrap (2a) of the orbiting scroll (2) is pressed against the wrap (1a) of the fixed scroll (1), and a contact pressing force (Fp) is generated between the wraps (1a) and (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 (K) makes the angle (θ) negative, that is, the angle (α). To co
Since tα is set to be positive, as is clear from the above formula, the contact pressing force (Fp) increases or decreases in response to the increase or decrease of the second pressing force (Fd) accompanying the increase or decrease of the internal pressure. To do. 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,
Correspondingly, the contact pressing force (Fd) is also reduced, and it is possible to prevent an unnecessarily excessive sliding resistance between the laps (1a) and (2a).

(Effects of the Invention) As described above, according to the present invention, the cam cam means (cam ring) (K) between the bearing hole (71) in the eccentric shaft portion (7) and the shaft (8) in the revolution scroll (2). And the angle (θ) is set to a range in which cotθ is negative, that is, the angle (α) is set to a range in which cotα is positive, the fixed scroll (1) and the revolution scroll (2)
The contact pressing force (Fp) of each lap (1a) (2a) with
It is possible to easily set a desired value without particularly 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]

FIG. 1 is a schematic vertical sectional view of an essential part of the embodiment of the present invention, FIG. 2 is a schematic plan sectional view of an essential part of the embodiment, FIG. 3 is the same vertical sectional view, and FIG. 4 is another embodiment. FIG. 5 is a schematic plan sectional view of an example, and FIG. 5 is an explanatory view showing a conventional example. (1) …… Fixed scroll (2) …… Revolution scroll (6) …… Crank shaft (7) …… Eccentric shaft (8) …… Shaft (71) …… Bearing hole (K) …… Cam ring (cam Means) (1a), (2a) ... Lap (Os), (Or), (Oc) ... Shaft center (θ) ... Angle

Claims (1)

[Claims] 1. Wraps (1a) (2a) each having a spiral shape
Equipped with a fixed scroll (1) and an orbiting scroll (2), a shaft (8) protruding from the rear surface of the orbiting scroll (2), and a bearing on the eccentric shaft portion (7) of the crankshaft (6). A scroll type fluid machine in which a hole (71) is formed, and the shaft (8) is inserted into the bearing hole (71) to connect the revolution scroll (2) and the crankshaft (6), The shaft center (Os) of the shaft (8) in the orbiting scroll (2) corresponds to the shaft center (Or) of the crankshaft (6) and the bearing hole (7) in the eccentric shaft portion (7).
1) The shaft center (Oc) of the crankshaft (6) and the shaft center (Os) of the orbiting scroll (2) are deviated from the shaft center (Oc) of 1). The line segment is (OsOr), and the second line segment connecting the shaft center (Os) of the shaft (8) and the shaft center (Oc) of the bearing hole (71) is (OsO).
c), and further, these line segments (OsOr) (OsOc)
Of the crankshaft (6) from the second line segment (OsOc) to the first line segment (OsOr).
The angle (θ) between the bearing hole (71) and the shaft (8) of the revolution scroll (2) is 0> A scroll-type fluid machine characterized in that cam means that is variable within a range of cotθ is provided.