JPS618403A - Scroll type hydraulic machine - Google Patents

Abstract

PURPOSE:To set contact pressure between a revolving scroll and a fixed scroll to a prescribed value by interposing a cam means between a shaft of said revolving scroll and an eccentric shaft of a crank shaft fitted to said shaft such that an angle theta set to those shafts is made variable in a range of 0<cottheta. CONSTITUTION:In the captioned machine wherein it sucks in and compresses a refrigerant and discharges it by revolving a revolving scroll 2 round a fixed scroll (not shown) engaged with the revolving scroll via a crank shaft 6 by means of a motor being driven, a cylindrical shaft 8 for supporting an eccentric shaft 7 of the crank shaft 6 is formed on the side of the rear surface of the revolving scroll 2. A cam ring 71 is interposed between the shaft 8 and the eccentric shaft 7, and a shaft center Os of the shaft 8 is displaced with respect to a shaft center Or of the crank shaft 6 and a shaft center Oc of the eccentric shaft 7. The cam ring 71 is formed such that an angle theta formed between a segment OsOr and a segment OsOc and adapted to turn in a direction of the rotatin of the crank shaft is made variable in a range of 0<cottheta.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a scroll-type fluid machine, and more particularly, a scroll-type fluid machine that includes a fixed scroll and a revolving scroll, and the revolving scroll is provided with a shaft portion that receives an eccentric shaft portion of a crankshaft. The present invention relates to a scroll type fluid machine in which the eccentric shaft portion is rotatably fitted into the shaft portion.

(Prior Art) In this type of fluid machine, a cam means is interposed between the shaft portion and the eccentric shaft portion, so that each of the above-mentioned Japanese Patent Laid-Open No. 56-12979 allows the contact pressure acting between scroll wraps to be easily set to a desired value.
1 has already been proposed.

To roughly explain this based on FIG. 7, a shaft portion (52) is provided on the back side of the revolving scroll (50) to receive an eccentric shaft portion (51) of a crankshaft (not shown), and the shaft portion (
A cam means (53) is provided between the eccentric shaft portion (52) and the eccentric shaft portion (51).
), and the cam means (53) allows the axial center (0r) of the crankshaft, the axial center (0c) of the eccentric shaft portion (51), and the shaft of the shaft portion (52) to be The positional relationship with the center (0s) is expressed by the line segment (
An included angle between Os 0c ) and a line segment (Os 0r ), where the included angle (θ) formed from the line segment (Os 0c ) in the rotational direction of the crankshaft is 90° and θ<180". Thus, due to the internal pressure of the closed space (not shown) formed by the fixed scroll (not shown) and the seven revolving scrolls (50), the wrap ( (not shown) acting in the radial direction (this pressing force (Fd) is
More precisely, the line segment (0r
This is the component force in the direction perpendicular to 0s). ), the wrap of the revolving scroll (50) is pressed against the wrap of the fixed scroll, and an appropriate sealing force (contact pressing force) (Fp) is applied between these wraps. Specifically, the contact pressing force (Fp) is approximately given by Fp=Fdcotθ...a. Furthermore, for comparison with the present application,
In the above relational expression, the component force (
Considering the pressing force) (Fr), the contact pressing force (F p)
When we derive the relational expression to find, Fl)=F(11-Fdcotθ-F r
-b. Further, (ω) in FIG. 7 indicates the rotation direction of the crankshaft.

(Problem to be solved by the present invention) However, in this case, when a compression action is performed in the closed space, the closed space sucks incompressible fluid (liquid compression), and the internal pressure of the closed space increases. However, when the pressing force (Fd) increases accordingly, as is clear from the above-mentioned relational expression (a), the included angle (θ) is larger than 90° and becomes 18
Since coto is a negative value in the range less than 0', the contact pressing force (Fp) increases in proportion to the pressing force (Fd). Therefore, in this conventional system, when the internal pressure of the sealed space becomes abnormally high during liquid compression, the contact pushing force (F
I) and ) also became too high, causing problems such as burning between the wraps of each of the scrolls and damage to these scrolls.

(Means for Solving the Problem) Accordingly, the present invention uses a cam means in the same way as in the prior art, and the axial center of the crankshaft, the axial center of the eccentric shaft portion, and the axial center of the shaft portion of the revolving scroll. The positional relationship between the liquid and the liquid is devised in a way different from the conventional one, so that it is possible to automatically prevent the generation of confining pressure when compressing the liquid as described above.
In detail, it has a fixed scroll and a revolving scroll,
In a scroll-type fluid machine in which the revolving scroll is provided with a shaft portion that receives an eccentric shaft portion of a crankshaft, and the eccentric shaft portion is rotatably engaged with the shaft portion, the shaft center of the shaft portion (
O5) with respect to the axial center (0r) of the crankshaft and the axial center (0c) of the eccentric shaft portion, and also align the crankshaft axial center (0r) and the shaft center axial center (0s). The connecting line segment is (O50r), the line segment connecting the shaft part axis (Os ) and the eccentric shaft part axis (0c) is (Os 0c ), and these line segments (Os 0r ) (Os 0c
) is the included angle formed by the line segment (Os 0c )
When the included angle formed in the rotational direction of the crankshaft is (θ), the included angle (θ) is defined between the eccentric shaft portion and the shaft portion.
), 0kuCot.

A cam means was installed to make the range variable.

(Function) As described above, the centrifugal force acting on the revolving scroll due to the rotation of the crankshaft acts to press the wrap of the scroll against the wrap of the fixed scroll, while The pressing force acting on the wrap of the revolving scroll due to the internal pressure of the closed space (compression chamber) formed by the
-7L/ wo acts to pull the fixed scroll away from the ramp, so during normal operation, by setting the moment due to the centrifugal force to be larger than the moment due to the pressing force, the wrap of the scroll is On the other hand, if an incompressible fluid flows into the sealed space and liquid compression occurs, and the internal pressure of the sealed space becomes abnormally high, the pressing force caused by this internal pressure may The moment grew bigger,
The revolving scroll is automatically pushed back around the axis of the eccentric shaft portion in a direction in which the wraps are separated from each other, and as a result, generation of confinement pressure in the closed space can be reliably prevented.

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

The one shown in Figures 2 and 3 is one in which the present invention is applied to a compressor for a refrigeration system, and a compression element (3) consisting of a fixed scroll (1) and a revolving scroll (2) is formed. The compression element (3) and the motor (4) that drives the compression element (3) are fixed to the frame (51) and the casing (5)
It is intended to be decorated.

An eccentric shaft portion (7) of the crankshaft (6) extends from the motor (4) to the back side of the revolving scroll (2).
A cylindrical shaft part (8) is formed which pivotally supports the shaft part (8).
The eccentric shaft portion (7) is fitted into the frame, while a sliding body (9) and a sliding body receiver (10) are provided between the back side of the revolving scroll (2) and the frame (A), A rotation prevention mechanism is provided to prevent rotation of the scroll (2).

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

(Thus, as the revolving scroll (2) revolves with respect to the fixed scroll (1) by driving the motor (4), the compression element (3) moves to the suction bow).
A low-pressure refrigerant is sucked in from the casing (12), the refrigerant is compressed, and a high-pressure refrigerant is passed through the discharge pipe (14) to the casing (5).
) It is as if it is being discharged outside.

Note 1. In FIG. 2, (15) and (1B) are bearings for supporting the crankshaft (6) on the bridge (A), respectively, and (17) is a bearing for supporting the revolving scroll (2) in the thrust direction. This is a thrust bearing for supporting the frame (A).

In the scroll type fluid machine configured as above,
As shown in FIGS. 2 and 3 and schematically shown in FIGS. 1 and 4, a cam ring (cam ring) is provided between the shaft portion (8) and the eccentric shaft portion (7) of the crankshaft (6). Means) (71) is interposed to align the axis (Os) of the shaft (8) with the axis (0r) of the crankshaft (6) and the axis (0r) of the eccentric shaft (7). 0c). Furthermore, (18)
is the bearing metal.

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 balance of moments regarding the axis (0c) of the eccentric shaft portion (7) will be explained.

To explain the pressing force acting on the revolving scroll (2) using FIG. 1, the force acting on the revolving scroll (2) is as follows. 1) The contact pushing force that the revolving scroll (2) receives based on the contact pressure with the wrap, the fist (Fw), is caused by the rotation of the revolving scroll (2) every time it rotates around the crankshaft (6). The centrifugal force (Fr) acting on the 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 clamp
The force applied on the line connecting the axis (0r) of the shaft (6) and the axis (Os) of the shaft (8) (hereinafter referred to as the first pressing force), (Fd'I is the same) Pressure force caused by internal pressure in a closed space
This is a component force in a 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 (0s) of the shaft (8) and the axis (0c) of the eccentric shaft (7) ) and the axis (Os 0c ) of the shaft portion (8).
) and the line segment (Os 0r ) connecting the axis (0r) of the crankshaft (6), and the line segment (Os 0r )
When the included angle formed in the rotational direction of the crankshaft (6) from (0c) is (θ), the axis (0c) of the eccentric shaft portion (7)
From the balance of moments centered on c), the following relationship holds true for the above-mentioned pushing force (pressing force), namely, Fp : Fw-(Fd cotθ+Fr ) −−−−
■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. Pressure (Fr), second pressing force (Fd)
is also determined by the design load. Then, these applied pushing forces (Fw) (Fr) (F
d) Under the conditions, the contact pressure (F
p) can be easily achieved as desired by appropriately setting the included angle (θ).

Furthermore, if the included angle (θ) is set within a range where cotθ is positive, even if the sealed space sucks liquid refrigerant and liquid compression occurs, the internal pressure of the space increases. The second pressing force (Fd) increases and eventually reaches the contact pressure (Fp) Mψ0, causing the revolving scroll (
2), a pressing force acts in a direction to separate the wraps of the scrolls (1) and (2). (Note that the first pressing force (Fr) also acts on the revolving scroll (2) to separate the wraps, but this first pressing force (Fr) is equal to the second pressing force (Fd). (Since the influence is small compared to the above, the explanation will be omitted below.) However, based on the above explanation, the cam ring ( 71), the included angle (
θ) within a range where COtθ is positive, and the contact pressure (
Fp) is set to an appropriate value.

In this embodiment, the included angle (θ) is set in a range larger than 0° and smaller than 90°, but as shown in FIG.
'It may be set to a smaller angle.

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

The motor (4) is driven to rotate the revolving scroll (
2) is revolved at a desired rotation speed and the fluid machine is operated steadily, the centrifugal force (Fw), as described above,
The first pressing force (Fr) and the second pressing force (Fd
Since both 'I' are almost constant during steady operation, as is clear from the relationship of the above-mentioned equation 0, the contact pressure (F, p) can be adjusted to the desired value depending on the set included angle (θ). It is determined by the value of .

On the other hand, when the sealed space sucks liquid refrigerant and liquid compression occurs, the internal pressure of the sealed space increases and the second pressing force (F d, ) increases significantly. Therefore, since the included angle (θ) is set in a range where cotθ is positive,
As the second pressing force (F, d) increases, the contact pressure (
Fp) not only decreases and eventually reaches 0, but also
The second pressing force (Fd) causes the orbiting scroll (2) to separate from the lap between the orbiting scroll (2) and the fixed scroll (1) around the axis (0c) of the eccentric shaft portion (7). It is swung in the direction of

As a result, a gap is created between the lamps, and the sealed space is released to the low pressure side through this gap, thereby preventing the generation of confinement pressure.

The structure in which the cam means is interposed between the eccentric shaft portion of the crankshaft and the shaft portion is similar to the sixth embodiment other than the above-mentioned embodiment.
As shown in the figure, the outer periphery of the eccentric shaft (7) is a cylindrical surface concentric with the axis (0r) of the crankshaft (6), and a receiving hole is formed in the center of the eccentric shaft (7). (72), and on the other hand, a shaft portion (8) that protrudes into the receiving hole (72) is formed on the back surface of the revolving scroll (2), and the eccentric shaft portion (7) and the shaft portion (8) are connected to each other. Cam means (cam ring) between
(71) may be interposed.

(Effects of the Invention) As described above, the cam means (71) is interposed between the eccentric shaft part (7) and the shaft part (8), and the included angle (θ )8COtθ is made variable within a positive range, so the included angle (θ
) is set appropriately in advance, the contact pressure (Fp) can be easily set to a desired value without increasing the machining accuracy of both scrolls (1) and (2). When the closed space inhales an incompressible fluid,
The sealed space is automatically opened to the low pressure side, thereby reliably preventing liquid compression and, therefore, reliably preventing damage to the scrolls (1) and (2).

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, 7 a plan view 1, Fig. 2 is a longitudinal sectional view of the main part of the embodiment, Fig. 3 is a plan sectional view of the main part of the embodiment, and Fig. 4 5 is a schematic longitudinal sectional view of the same embodiment, FIG. 5 is a schematic explanatory diagram of another embodiment, FIG. 6 is a schematic longitudinal sectional view of another embodiment, and FIG. 7 is an explanatory diagram showing a conventional example. (1)...Fixed scroll (2)...Revolving scroll (6)...Crankshaft (7)...Eccentric shaft (8)...Shaft (71) ...Cam means (θ)...Included angle Fig. 1 Fig. 4 Fig. 5

Claims (1)

[Claims] (1) A fixed scroll (1) and a revolving scroll (2) are provided, and a crankshaft (6) is attached to the revolving scroll (2).
A shaft portion (8) is provided to receive the eccentric shaft portion (7) of the shaft portion (
8), in which the eccentric shaft (7) is rotatably fitted into the scroll-type fluid machine;
s) with respect to the axial center (0r) of the crankshaft (6) and the axial center (0c) of the eccentric shaft portion (7), and the axial center (0r) of the crankshaft (6) The shaft portion (8
) is the line segment connecting the axis (0s) of the shaft (0s), the axis (0s) of the shaft (8) and the axis (0s) of the eccentric shaft (7)
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 (0s0c) in the rotational direction of the crankshaft (6). When the included angle is (θ), a cam means is provided between the eccentric shaft portion (7) and the shaft portion (8) to vary the included angle (θ) within a range of 0<cotθ. A scroll-type fluid machine characterized by an intervening device.