JPS641668B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a swash plate type compressor used in a refrigerator or the like, and particularly to a variable capacity compressor.

(Prior Art) Compressors that compress fluid (refrigerant) by converting the rotational motion of a swash plate into reciprocating motion of a piston have been known. There is a compressor that changes the stroke amount of a piston attached to a swash plate, thereby changing the compression capacity (compression ratio).

The above-mentioned variable capacity compressor generally includes a variable-angle cam rotor attached to the shaft shaft, and a rocking plate that rocks to follow the cam rotor and whose angle changes as the angle of the cam rotor changes. The above-mentioned swash plate is substantially formed by the cam rotor and the rocking plate, which are disposed in the crank chamber, and the piston, which is connected to the rocking plate through the connecting rod, swings. The stroke amount was changed in accordance with the change in the inclination angle of the plate, thereby changing the compression capacity.

(Problems to be Solved by the Invention) However, in this compressor, the structure for supporting the rocking plate on the cam rotor and the bearing structure for changing the angle of the cam rotor are complicated, and furthermore, the rocking plate is complicated. A rotation prevention mechanism must be provided to prevent rotational movement of the moving plate.

In addition, this rotation prevention mechanism must function properly even if the inclination angle of the rocking plate changes, so a rotation prevention mechanism that combines bevel gears, which is used in constant capacity compressors, is used. Therefore, the rotation prevention mechanism of a variable capacity compressor consists of a so-called slide rod that protrudes radially from the outer periphery of the rocking plate, and a guide provided in the crank chamber housing in the axial direction of the shaft shaft. having a groove;
The structure is such that the slide rod slides in the guide groove to prevent rotational movement of the rocking plate. However, this rotation prevention mechanism has problems with the durability of the sliding parts, and when the angle of inclination of the rocking plate with respect to the shaft axis is large, the transmitted rocking angular velocity is not constant and vibrations occur. The points were also hot.

SUMMARY OF THE INVENTION An object of the present invention is to provide a variable capacity compressor with a simple structure and a highly reliable rotation prevention function.

(Structure of the Invention) According to the present invention, when the swash plate is rotated by rotation of the shaft shaft, a crank chamber and a swash plate disposed in the crank chamber are connected to a plurality of pistons that reciprocate and move the pistons. A coupling mechanism for slidably coupling to the swash plate along the circumference of the swash plate, and a hinge for supporting the swash plate to the shaft shaft so that the inclination angle of the swash plate can be varied within a predetermined range. and an adjusting means for adjusting the pressure in the crank chamber, and a sliding shoe having a spherical surface is placed on both sides of the swash plate along the circumference of the swash plate with the relief surface facing outward. In addition, the pair of sliding shoes are in contact with both sides of the swash plate so as to substantially form a sphere, and one end of the piston is arranged to sandwich the pair of sliding shoes. The above-mentioned coupling mechanism is constructed by adjusting the pressure in the crank chamber to change the angle of the swash plate, thereby changing the compression capacity. This is a variable capacity swash plate compressor.

(Example) Hereinafter, the present invention will be explained using examples shown in the drawings.

First, the structure of a variable capacity compressor according to the present invention will be explained with reference to FIG.

A cylinder block 2 in which a cylinder bore 2a is formed is formed at one end of the cylinder casing 1, and a through hole 3a for inserting a shaft shaft 4 is formed in the opening at the other end. A front housing 3 in which a radial bearing 5 for rotatably supporting the shaft shaft 4 is press-fitted is arranged and fixed in the hole 3a.

A shaft shaft lead-out cylinder 3b is provided at the outer end of the through-hole 3a of the front housing 3 and protrudes to enclose the shaft shaft 4, and a space is formed by the shaft shaft 4 and the inner wall of the shaft shaft lead-out cylinder 3b. A mechanical seal 7 is arranged with the seal chamber 6 as the seal chamber 6. A crank chamber 1a is formed between the inner wall of the front housing 3 and one end surface of the cylinder block 2, and a rotor 8 is fitted into the side end of the shaft shaft 4 within the crank chamber 1a. One end portion of the rotor 8 is bent in the direction of the shaft axis 4 and has an ear portion 8a formed in an ear shape. A long hole 8b is provided in this ear portion 8a.

The shaft shaft 4 has a rotor 8 and a space therebetween.
A spherical bush 9 is slidably disposed on the shaft shaft 4, and a disk-shaped swash plate 10 is provided on the spherical surface of the spherical bush 9 so as to be slidable on the spherical surface. Further, on one end surface of the swash plate 10, an ear portion 10a is formed in an ear shape toward the ear portion 8a of the rotor 8.
A hole 10b is provided corresponding to the elongated hole 8b.
have. A pin-shaped member 11 is slidably inserted into the elongated holes 8b and 10b to form a so-called hinge mechanism. Further, the rotor 8 and the spherical bush 9 are connected by a spring 12 arranged parallel to the shaft shaft 4. Note that a thrust race 13 is arranged between the inner wall surface of the front housing 3 and the rotor 8, and a thrust needle bearing 14 is sandwiched between the thrust races 13.

The other end of the shaft shaft 4 is connected to the cylinder block 2.
, a thrust needle bearing 16 and a leaf spring 1 are rotatably supported by a radial bearing 15 and further arranged on an end surface of the shaft shaft 4.
7, and is rotatably supported by an adjusting screw 18.

Sliding shoes 19 having spherical surfaces formed on both sides of the swash plate 10 are in contact with the swash plate 10 with the spherical surfaces facing outward. This sliding shoe 19 is slidable along the circumference of the swash plate 10. Further, as shown in the figure, the pair of sliding shoes 19 are arranged so as to form a substantially spherical body with a radius R, for example. As shown in the figure, a piston rod 20 having a bifurcated end is disposed to sandwich the sliding shoe 19, and the piston rod 20 is mounted on the sliding shoe 19. is in a state where it can be slid. A piston 21 is provided at the other end of the piston rod 20 so as to be slidable within the cylinder bore 2a. Note that a plurality of pistons having the above-described structure are provided on the swash plate 10.

A suction hole 22 for sucking in fluid and a discharge hole 23 for discharging fluid are bored in one end surface of the cylinder bore 2a. A valve plate 24 with connected valves and discharge valves is connected to the cylinder block 2 via a gasket 25, and a suction chamber 27 is connected by a cylinder head 26 having a partition 26a.
The cylinder head 26 is connected to the valve plate 24 through a gasket 29 so that a discharge chamber 28 is formed.
The valve plate 24 and cylinder head 26 are fixed on the cylinder block 2, and the cylinder casing 1 is closed. In addition, the suction chamber 27
A suction port 27a is connected to the discharge chamber 28, and a discharge port 28a is provided in the discharge chamber 28.

Furthermore, a communication hole 30 is provided through the cylinder block 2 formed in the cylinder casing 1 to connect the suction chamber 27 and the crank chamber 1a. This communication hole 30 includes an introduction hole 30a passing through the valve plate 24 and gaskets 25, 29, and a communication hole portion 30 for arranging a bellows, which will be described later.
It is composed of b.

A coupling ring 31 having a passage hole 31a and a valve seat 31b is fitted into the communication hole 30b on the crank chamber 1a side, and an O-ring 32 is inserted into the end of the coupling ring 31 to prevent gas leakage. moreover,
A pedestal 33 having through holes 33a at both ends of its upper surface is fixed to the communication hole 30b, and a bellows 34 having a needle 34a at its tip and filled with gas at a constant pressure is arranged on the upper surface of the pedestal 33. ,
When the tip of the needle 34a is inserted into the passage hole 31a, the passage hole 31a is closed by the base 31b and the needle 34a.

Next, referring to FIGS. 1 and 2, a case where the operation of the compressor having the above-described structure is used in a refrigeration system will be described.

When a rotational force is applied to the shaft shaft 4, this rotational force is transmitted to the swash plate 10 through the rotor 8 and the above-mentioned hinge portion, and the swash plate 10 rotates. As the swash plate 10 rotates, the sliding shoe 19 rotates the swash plate 10.
Since the piston rod 20 slides on the circumference of the sliding shoe 19, no rotational force is transmitted to the piston rod 20 connected to the sliding shoe 19. i.e. piston 2
1, there is virtually no movement in the vertical direction in the figure. Therefore, the rotational force of the swash plate 10 is converted into a reciprocating motion of the piston 21 (in the left-right direction in the figure). Due to the reciprocating movement of the piston 21, the fluid (refrigerant) sucked into the cylinder bore 2a from the suction hole 22 is compressed and then discharged into the discharge chamber 28 through the discharge hole 23.

Furthermore, to explain the case where the compression capacity of this compressor is changed, in this refrigeration system, the heat load is higher than the predetermined set temperature,
Furthermore, if the refrigerating capacity is insufficient, in this case, the refrigerant suction pressure will increase and the suction chamber 2
7 pressure increases. Therefore, the pressure in the communication hole 30b communicating with the suction chamber 27 also increases.

Bellows 34 arranged in the communication hole 30b
is filled with gas so that the pressure is slightly higher than the suction pressure that corresponds to the preset temperature of the refrigeration system. Therefore, when the heat load is higher than the set temperature, the bellows 34 contracts to the right as shown in FIG.
The suction chamber 27 and the crank chamber 1a communicate with each other by being separated from the valve seat 31b provided in the passage hole 31a.

Blow-by gas leaking from the cylinder bore chamber 2a to the crank chamber 1a due to the operation of the compressor escapes to the suction chamber 27, so the pressure inside the crank chamber 1a decreases and becomes almost equal to the pressure in the suction chamber 27.

On the other hand, a gas compression reaction is applied to the swash plate 10 during the compression stroke by pistons arranged on the swash plate 10 at equal angular intervals. The resultant force of this reaction is received by the hinge portion described above. The moment around the hinge due to the reaction force acting on each piston is larger than the moment due to the piston (not shown) located at the lower end of the swash plate 10 in FIG. In the plane, a moment M ₁ that rotates the hinge portion to the right acts on the hinge portion.

Here, the moment generated on the hinge by the spring 12 is _M2 (in this case, it acts toward the left in the figure), and the moment generated on the hinge due to the pressure difference between the crank chamber 1a and the suction chamber 27 is M2. of
If M ₃ , in the above case, the suction chamber 27
Since the pressure in the crank chamber 1a is almost equal to the pressure in the crank chamber 1a, the only moment opposite to _M1 is _M2 . Therefore, if the elastic force of the spring 12 is determined in advance so that M ₁ >M ₂ , the inclination angle of the swash plate 10 will increase due to the clockwise moment about the hinge portion. Then, the angle of inclination of the swash plate 10 is inclined until the pin 11 of the hinge section moves to the upper end of the elongated hole 8b, and the angle of inclination of the swash plate 10 becomes the maximum with respect to the shaft axis 4. (Based on the case where the swash plate and the shaft axis are perpendicular to each other.) As a result, the stroke amount of the piston 21 increases, and the capacity of the compressor increases.

Next, when the heat load becomes low or the capacity of the compressor becomes excessive due to use of the compressor in a high-speed range, the suction pressure of the refrigerant decreases, and the pressure in the suction chamber 27 decreases. Therefore, the pressure in the communication hole 30b communicating with the suction chamber 27 also gradually decreases. Therefore, the bellows 34 contracts less and moves to the left, as shown in FIG. As a result, the tip of the needle 34a is inserted into the passage hole 31a, the passage hole 31a is closed by the valve seat 31b and the needle 34a, and the suction chamber 27 and the crank chamber 1 are closed.
a is blocked.

The pressure in the crank chamber 1a increases due to blow-by gas leaked from the cylinder bore chamber 2a to the crank chamber 1a due to the operation of the compressor. Therefore, the moment M ₃ acts to the left around the hinge part, and at a certain point, M ₁ < M ₂ + M ₃ and,
A leftward moment acts on the swash plate 10 around the hinge portion, and the inclination angle of the swash plate 10 gradually becomes smaller. Then, the inclination angle of the swash plate 10 becomes smaller until the pin 11 of the hinge portion moves to the lower end of the elongated hole 8b. As a result, the stroke amount of the piston 27 becomes smaller, and the capacity of the compressor decreases.

Note that the length of the elongated hole 8b of the hinge portion is determined so that the minimum compression capacity is 20 to 30% of the maximum compression capacity.

As shown in FIG. 3a, a hemispherical sliding shoe 19 (with radius B) is attached to the swash plate 10.
(The thickness of the swash plate at this time is t.) When disposed on both sides of the swash plate, the distance A between the spherical surfaces of the pair of sliding shoes 19 is expressed by the following equation (1).

A=2B+t×1/cosα (1) where α is the angle between the vertical axis and the central axis of the swash plate 10.

As mentioned above, since the angle of inclination of the swash plate 10 changes, the distance A between the spherical surfaces expressed by equation (1) changes in accordance with the angle of inclination of the swash plate 10. Therefore, since the distance between the piston rod 20 and the sliding shoe 19 is predetermined, a gap may occur between the sliding shoe 19 and the swash plate 10 as shown in FIG. 3b. In some cases, the smooth movement of the piston may be disturbed.

On the other hand, as shown in FIG. 4, sliding shoes 19 each having a spherical surface are disposed on both sides of the swash plate 10.
9 are arranged so as to substantially form a sphere (radius is R) centered on a point on the central axis of the swash plate 10, the distance A' between the spherical surfaces is expressed as A'=2R. . Therefore, in this case, the distance A′ between the spherical surfaces is the swash plate 1
It is always constant regardless of the inclination angle α of 0. Therefore, there is no gap between the sliding shoe 19 and the swash plate 10, and the piston can always operate smoothly.

(Effects of the Invention) As explained above, according to the present invention, the piston can substantially slide along the circumference of the swash plate, thereby eliminating the need for a oscillating plate that was conventionally required. Furthermore, since the rotor and swash plate are connected by a hinge mechanism, the tilt angle of the swash plate can be controlled within a predetermined range. The compression capacity of the compressor can be easily controlled.

In addition, the pair of sliding shoes placed in contact with both sides of the swash plate substantially form a sphere.
Since the swash plate and the piston are connected by the pair of sliding shoes, even if the inclination angle of the swash plate changes, there is no gap between the sliding shoe and the swash plate. This has the advantage of ensuring smooth movement of the piston.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a variable capacity compressor according to the present invention with the swash plate at its maximum angle of inclination, and FIG. 2 shows a variable capacity compressor according to the invention with its swash plate at its minimum angle of inclination A sectional view shown in FIG. 3A is a diagram showing a conventional connection mechanism between a piston and a swash plate, FIG. 3B
3A is a diagram showing a state in which a gap is created between the swash plate and the sliding shoe due to a change in the inclination angle of the swash plate in the connection mechanism shown in FIG. It is a figure for showing the connection mechanism with a swash plate. 1...Cylinder casing, 2...Cylinder block, 3...Front housing, 4...
Shaft axis, 5... Radial bearing, 6...
Seal chamber, 7... Mechanical seal, 8... Rotor, 9... Spherical bushing, 10... Swash plate, 11...
... Pin-shaped member, 12 ... Spring, 13 ... Thrust race, 14 ... Needle bearing, 1
5... Radial bearing, 16... Thrust needle bearing, 17... Leaf spring, 18... Adjustment screw, 19... Sliding shoe, 20... Piston rod, 21... Piston, 22... Suction hole , 23...discharge hole, 24...
Valve plate, 25, 29...Gasket, 26...Cylinder head, 27...Suction chamber, 28...Discharge chamber, 30...Communication hole, 31...Coupling, 3
2...O-ring, 33...pedestal, 34...bellows.

Claims (1)

[Claims] 1 A crank chamber, a swash plate disposed in the crank chamber, a plurality of pistons that reciprocate when the swash plate rotates due to rotation of a shaft shaft, and a plurality of pistons that move the pistons along the circumference of the swash plate. a coupling mechanism for slidably coupling to the swash plate; a hinge mechanism for supporting the swash plate to the shaft shaft so that the inclination angle of the swash plate can be varied within a predetermined range; and an adjusting means for adjusting the pressure in the crank chamber, and a sliding shoe having spherical surfaces on both sides of the swash plate is slidable along the circumference of the swash plate with the spherical surfaces facing outward. Further, the pair of sliding shoes are in contact with both surfaces of the swash plate so as to substantially form a sphere, and one end of the piston is arranged to sandwich the pair of sliding shoes. The coupling mechanism is configured to change the angle of the swash plate by adjusting the pressure in the crank chamber, thereby changing the compression capacity. Variable swash plate compressor.