JPS618408A - Scroll type hydraulic machine - Google Patents

Abstract

PURPOSE:To set contact pressure between a fixed scroll and a revolving scroll to a desired value by interposing a prescribed cam mens between a bearing hole provided in an eccentric bearing of a crank shaft and a shaft of said revolving scroll fitted in said bearing hole. CONSTITUTION:In the captioned machine wherein a revolving scroll 2 is revolved round a fixed scroll (not shown) engaged therewith via a crank shaft 6 by driving a motor and thereby a refrigerant is sucked in, compressed, and discharged, a shaft is provided projecting on the side of the rear surface of the revolving scroll 2, which shaft is fitted in a bearing hole 71 formed in an eccentric shaft 7 of the crank shaft 6. A cam ring K is interposed betwen said shaft 8 and said bearing hole 71, and a shaft center Os of the shart 8 is displaced with respect to shaft centers Or, Oc of the crank shaft 6 and the bearing hole 71. The cam ring K is formed such that an angle alpha formed between a segment OsOr and a segment OsOc in a direction of the rotation of the crank shaft from the segment OsOr is variable in a range 0<cotalpha.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a scroll-type fluid machine, and more specifically, a fixed scroll and a revolving scroll each having a spiral wrap, and a shaft protruding from the back surface of the revolving scroll. The present invention also 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 couple the revolving scroll and the crankshaft.

(Prior Art) The scroll-type fluid machine configured as described above is already known, as it is also described in Japanese Patent Laid-Open No. 58-79684.

By the way, as schematically shown in Fig. 5, in this case, a fixed scroll (50) and a revolving scroll (51) are assembled facing each other, and a sealed space (52) is formed between these scrolls (50) and (51). However, in order to ensure the airtightness of this sealed space (52), conventionally, the dimensions of each of the scrolls (50) and (51) are appropriately set, and the scrolls are assembled by (51
) (50), an appropriate contact pressure force is applied in the radial direction between the wraps (53) and (54) of the wraps (50).

Note that (55) is a shaft provided on the back surface of the revolving 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 revolving scroll (51) and the crankshaft (56) are coupled together.

(Problems to be Solved by the Present Invention) However, when assembling the respective scrolls (50) and (51), it is sometimes difficult to set the contact pressing force to a desired value. Manufacturing errors and assembly were extremely difficult due to errors.

In addition, if the contact pressing force changes due to the above-mentioned assembly so that the contact pressing force remains constant during operation, the contact pressing force changes, for example,
When the load is large, the contact pressing force is insufficient and the sealing performance of the closed space (52) is reduced, while when the load is small, the contact pressing force is too large for this load, Although the sealing performance is ensured, the above-mentioned wrap (53
) (54) caused an unnecessarily large power loss.

(Means for Solving the Problems) Accordingly, the present invention includes a cam means interposed between the shaft of the revolving scroll and the bearing hole of the eccentric shaft portion, and the revolving scroll is arranged at the axis of the bearing hole. The contact pushing force can be set by using the centrifugal force acting on the revolving scroll and the pushing force caused by the internal pressure of the closed space, The configuration includes a fixed scroll and a revolving scroll, each having a spiral wrap, a shaft protruding from the back surface of the revolving scroll, a bearing hole formed in the eccentric shaft portion of the crankshaft, and a bearing hole formed in the eccentric shaft portion of the crankshaft. In a scroll type fluid machine in which the revolving scroll and the crankshaft are connected by inserting a shaft therein, the axis of the shaft of the revolving scroll (
0s) with respect to the axis (0r) of the crankshaft and the axis (0c) of the bearing hole in the eccentric shaft portion, and the axis (0r) of the crankshaft and the axis of the revolving scroll The line segment connecting the axis (0s) of (0s 0
r ), the axial center of the shaft (O5) and the axial center of the bearing hole (
0c) is defined as (0s 0c ), and furthermore, the included angle formed by these line segments (0s 0r ) (0s 0c), which extends from the line segment (0s0r-) in the rotational direction of the crankshaft. When the included angle formed is (α), the included angle (α) is between the bearing hole and the shaft of the revolving scroll.
) is provided with a cam means that makes it variable within the range of 0<cotα.

(Function) As configured as above, when the fluid machine is operated, due to the centrifugal force acting on the revolving scroll and the pressing force caused by the internal pressure of the closed space formed by the fixed scroll and the revolving scroll, The revolving scroll is swung around the axis of the bearing hole in the eccentric shaft portion in a direction in which the wrap of the scroll is pressed against the wrap of the fixed scroll, so that a contact pushing force acts between these wraps, Moreover, this contact pressing force can be determined by setting the included angle (α), and the contact pressing force increases or decreases in response to an increase or decrease in the internal pressure of the sealed space, and as a result, the sealing performance between the wraps is improved. is always kept in good condition.

(Example ) Embodiments of the present invention will be described below based on the drawings.

The one shown in FIG.
) (2a) forming a compression element (3) consisting of a fixed scroll (1) and a revolving scroll (2), the compression element (3) and a motor (4) for driving the compression element (3); is fixed to the frame (A) and installed inside the casing (5).

A shaft (8) is mounted on the back side of the revolving scroll (2).
The crankshaft (6) extending from the motor (4) is provided with an eccentric shaft portion (7) having a cylindrical outer surface concentric with the crankshaft (6), and the eccentric shaft portion (7) is provided with a , a bearing hole (7) whose axis is eccentric from the axis of the crankshaft (6).
1), and by inserting the shaft (8) of the revolving scroll (2) into the bearing hole (71), the revolving scroll (2) and the crankshaft (6) are connected. There is.

Further, the back side of the revolving scroll (2) and the bridge (
A) is provided with an Oldham ring (9) to prevent rotation of the scroll (2).

Further, a suction pipe (11) is connected to the casing (5) to make the inside of the casing (5) low pressure, and a suction pipe (12) is provided in the compression element (3) in the casing (5). ) is opened, while the compression element (3
A discharge pipe (14) is connected to a discharge boat (13) provided in ) so that this discharge port (13) is opened to the outside of the casing (5).

In this way, as the revolving scroll (2) revolves around the fixed scroll (1) by driving the motor (4), the compression element (3) draws low-pressure refrigerant from the suction bow (12). The refrigerant is compressed and the high-pressure refrigerant is discharged out of the casing (5) through the discharge pipe (14).

In Fig. 3, (15) (IEi) are radial bearings for supporting the crankshaft (6) on the frame (A), and (17) is a radial bearing for supporting the crankshaft (6) on the frame (A).
A thrust bearing (18) is a bearing metal for supporting the bridge (A) in the thrust direction.

In the scroll type fluid machine configured as above,
As schematically shown in FIGS. 1 and 2, a cam ring (cam means) (
K) interposed between the shaft center (0s) of the shaft (8) and the shaft center (0r) of the crankshaft (6) and the eccentric shaft section (
7) with respect to the axis (0c) of the bearing hole (71). In FIG. 2, (ω) indicates the direction of rotation of the crankshaft (6).

Below, in specifically explaining this configuration, first,
The forces acting on the revolving scroll (2) and the above of these forces when the fluid machine is connected to an evaporator and a condenser (none of which are shown) and is operated in a steady state. The axis of the bearing hole (71) in the eccentric shaft portion (7) (
The balance of moments regarding 0c) will be explained.

To explain the pressing force acting on the revolving scroll (2) using FIG. 2, the force acting on the revolving scroll (2) is as follows: - (Fp) is the revolving scroll (2)'s wrap (2)
The contact pushing force that the revolving scroll (2) receives due to the contact between a) and the wrap (1a) of the fixed scroll (1); The centrifugal force, .(Fr), which acts on the revolving scroll (2) by rotating the revolving scroll (2) is caused by the internal pressure of the closed space (compression chamber) formed by the fixed scroll (1) and the revolving scroll (2). The pressing force acting on the revolving scroll (2) is the axial center (0r) of the crankshaft (6) and the axial center (0s) of the shaft (8).
) (hereinafter referred to as the first pressing force)
, ・(Fd) is the pressing force caused by the internal pressure of the sealed space,
A component force (in the direction perpendicular to the first pressing force (Fr))
(hereinafter referred to as the second pressing force).

Therefore, on a virtual plane perpendicular to the axis (0r) of the crankshaft (6), the axis (O
5) and the axis (0c) of the bearing hole (71) in the eccentric shaft portion (7) (0s 0c ), and the line segment (0s 0c ) connecting the shaft (
8) and the axis (0s) of the crankshaft (6).
The included angle with the line segment (0s 0r ) connecting r),
When the included angle formed from the line segment (0sor) in the rotational direction of the crankshaft (6) is (α), the eccentric shaft portion (7
), the following relationship holds true for the above-mentioned pushing force (pressing force): Fp = Fv - FFd co t a-Fr
−−・− ■ The centrifugal force (Fw) is generated by the motor (4
) is determined by the set rotation speed, and
Since the internal pressure of the sealed space is determined by the design load during normal operation, the first pressing force (Fr) and the second pressing force (Fd) are also determined by the design load. Then, these applied pushing forces (Fw) (Fr
) (Fd) Under the condition, the contact pushing force (Fp) during normal operation can be easily made desired by appropriately setting the included angle (α).

Note that the first pressing force (Fr) is centrifugal force (FW), the second
Since it is considerably smaller than the pressing force (Fd), the first pressing force (Fr) will be omitted in the following explanation.

Therefore, when assembling the revolving scroll (2) to the fixed scroll (1), the revolving scroll (2) is attached to the fixed scroll (1).
) and the bearing hole (7) in the eccentric shaft portion (7).
1), the cam ring (K) to be interposed between the cam ring (K) and ) becomes the desired value. Specifically, the included angle (α) may be set in a range larger than Oo and smaller than 90° as shown in FIG. 1, or larger than 180′ as shown in FIG. It may be set within a range smaller than 270°.

The operation of the scroll type fluid machine constructed as above will be explained.

When the motor (4) is driven, the revolving scroll (2) revolves, and as described above, the compression element (3)
A compression effect occurs.

Therefore, on the revolving scroll (2), the centrifugal force (Fw) accompanying the revolution (rotation), the compression element (3)
The second pressing force (Fd) due to the internal pressure of is applied.

Since the cam ring (K) is interposed between the bearing hole (71) in the eccentric shaft portion (7) and the shaft (8), the labor-saving (F
w) and (Fd) generate a rotational moment about the axis of the bearing hole (71) in the eccentric shaft portion (7),
The wrap (2a) of the revolving scroll (2) is pressed against the wrap (1a) of the fixed scroll (1), and a contact pressing force (Fp) is generated between each wrap (1a) (2a).

Moreover, this contact pressing force (Fp) is
As is clear from Equation 1, it can be easily set by setting the included angle (α). Furthermore, when the load of this fluid machine changes and the internal pressure of the compression element (3) increases or decreases, the included angle (α) is set by the cam ring (K) so that co'tα becomes positive. Therefore, as is clear from equation 0, the contact pressing force (Fp) increases or decreases in response to the increase or decrease in the second pressing force (Fd) as the internal pressure increases or decreases. That is, when the internal pressure of the compression element (3) increases, the contact pressing force (Fd) increases accordingly, and the compression element (3)
While the sealing performance of the sealed space inside can be ensured, if the internal pressure becomes small, the contact pressing force (F
d) is also reduced, thereby preventing unnecessary excessive sliding resistance from occurring between the wraps (1a) and (2a).

(Effects of the Invention) As described above, the present invention provides a cam means (cam ring) (K) interposed between the bearing hole (71) in the eccentric shaft portion (7) and the shaft (8) in the revolving scroll (2). is interposed, and the included angle (α) is set in a range where cotα is positive, so the contact pushing force of each wrap (1a) (2a) between the fixed scroll (1) and the revolving scroll (2) is (Fp) can be easily set to a desired value without particularly reducing manufacturing tolerances and assembly errors.

In addition, since the contact pressing force (Fp) can be increased or decreased according to load fluctuations, the sealing performance of the closed space can be maintained well even in response to load fluctuations, and the wraps (1a) (2a ) There is no possibility that unnecessarily large sliding resistance will occur between the two, resulting in power loss.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view of the main part of an embodiment of the present invention, FIG. 2 is a schematic plan sectional view of the main part of the same embodiment, FIG. 3 is a longitudinal sectional view of the same, and FIG. 4 is another embodiment. FIG. 5, which is a schematic plan sectional view of an example, is an explanatory diagram showing a conventional example. (1)...Fixed scroll (2)...Revolving scroll (6)...Crankshaft (7)...Eccentric shaft (8)...Shaft (71)... Bearing hole (, K)... Cam ring (cam means) (1a),
(2a)...Wrap (0s), (0r), (0c)...Axis center diagram 2

Claims (1)

[Claims] (1) A fixed scroll (1) and a revolving scroll (2) each having spiral wraps (1a) and (2a) are provided, and a shaft (8) is provided protruding from the back surface of the revolving scroll (2), A bearing hole (71) is formed in the eccentric shaft portion (7) of the crankshaft (6), and the shaft (8) is inserted into the bearing hole (71) so that the revolving scroll (2) and the crankshaft (
6), in which the shaft (8) of the revolving scroll (2)
The axial center (0s) of the crankshaft (6) is the axial center (0r
) and the eccentric shaft portion (7) with respect to the axis (0c) of the bearing hole (71), and the crankshaft (
6) and the axis (0r) of the revolving scroll (2)
The line segment connecting the axial center (0s) of the shaft (8) with the axial center (0s) of the shaft (8) is (0s0r), and the axial center (0s) of the shaft (8) and the axial center of the bearing hole (71) (
0c) is defined as (0s0c), and furthermore, an included angle formed by these line segments (0s0r) and (0s0c), which is formed from the line segment (0s0r) in the rotational direction of the crankshaft (6). When the included angle is (α), the included angle (α) between the bearing hole (71) and the shaft (8) of the revolving scroll (2) is variable within the range of 0<cotα. A scroll-type fluid machine characterized by having a cam means interposed therein.