JPH0545800B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scroll compressor, and more particularly to a scroll compressor in which the compression section is securely sealed in the radial direction.

First, the principle of a scroll compressor will be briefly described.

1A to 1D show the basic structure of a scroll compressor, in which 1 is a fixed scroll, 2 is an oscillating scroll, 5 is a compression chamber formed by the gap between the fixed scroll 1 and the oscillating scroll 2; 6 is a suction chamber, and 8 is a discharge chamber formed at the innermost periphery of each scroll 1, 2. Further, O is the center of the fixed scroll 1. The fixed scroll 1 and the oscillating scroll 2 have the same shape and are wound in the same direction but out of phase by 180 degrees.The spiral form is an involute or a combination of circular arcs, etc. , 2 are combined to form a compression chamber 5 between both spirals.

Next, the operation will be explained. In FIGS. 1 a to d, the fixed scroll 1 is stationary with respect to space, and the swinging scroll 2 is combined with the fixed scroll 1 as shown in the figure, and the posture of the swinging scroll 2 in the circumferential direction is changed. In other words, the fixed scroll 1 is rotated around the center O without rotating, and thereby the swinging scroll 2 is continuously changed from a to d in FIG. 1 relative to the fixed scroll 1. let With this movement of the oscillating scroll 2, the compression chamber 5 gradually reduces its volume from the suction chamber 6 to the discharge chamber 8, thereby compressing the gas sucked into the compression chamber 5 from the suction chamber 6. The liquid is discharged into the discharge chamber 8 in the center of the fixed scroll 1.

The above is an explanation of the general operation of a scroll compressor.

Next, a conventional scroll compressor having the above-mentioned principle function will be explained with reference to FIGS. 2 to 4.

FIGS. 2 to 4 show examples of scroll compressors used in, for example, refrigeration, air conditioning, or air compressors, and are configured as compressors for gases such as fluorocarbons. In the figure, 1 is a fixed scroll, and 1a is a base plate of the fixed scroll 1, which also serves as a part of a shell to be described later. 2 is an oscillating scroll, 3 is a base plate of the oscillating scroll 2,
Reference numeral 4 denotes an oscillating scroll shaft protruding from the center of the back surface of the base plate 3, 5 a compression chamber formed by both scrolls 1 and 2, 6 a suction chamber of the compression chamber 5, and 7 a gas body communicating with the suction chamber 6. 8 is a discharge chamber of the compression chamber 5; 8a is a discharge hole communicating with the discharge chamber 8; 9 is a thrust bearing that supports the back surface of the base plate 3 of the swinging scroll 2; 10 is the fixed scroll 1 and bolts, etc. 11 is a ring-shaped Oldham joint for preventing rotation of the oscillating scroll 2 and connecting it to the bearing support 10 so as to be able to swing in the radial direction; 12 is a base plate 3 of the oscillating scroll 2; 13 is an oil return hole drilled in the bearing support 10 so as to communicate the Oldham chamber 12 with a motor chamber, which will be described later. 14 is a crankshaft that drives the oscillating scroll 2. An oil hole 15 is eccentrically formed in the crankshaft 14 along its longitudinal direction. Further, 16 is a swing bearing provided at the upper end of the crankshaft 14 at a fitting portion where the swing scroll shaft 4 fits eccentrically with respect to the axis of the crankshaft 14; 17 is a swing bearing provided at the upper end of the crankshaft 14;
18 is a motor-side bearing that supports the lower part of the crankshaft 14; 19 is a motor-side bearing that supports the lower part of the crankshaft 14;
20 is a motor rotor integrated with the crankshaft 14, 21 is a first balance member fixed to the crankshaft 14 at the upper part of the rotor 20, and 22 is the rotor 20.
23 is a shell that supports the fixed scroll 1, bearing support 10, motor stator 19 and motor side bearing 18 and seals the entire compressor; 24 is a shell fixed to the bottom of the shell 23; The stored oil 25 is a motor chamber that accommodates the motor stator 19, motor rotor 20, and the like.

In addition, in FIGS. 3 and 4, r is the eccentricity of the swing bearing (swing scroll shaft) from the axis of the crankshaft 14 (center O of the fixed scroll 1),
Fc is the centrifugal force between the oscillating scroll 2 and the base plate 3, etc. generated during the orbiting motion of the oscillating scroll 2, Fg is the gas load in a direction almost perpendicular to the centrifugal force Fc, and F is the difference between the centrifugal force Fc and the gas load Fg. The resultant force, C, is the gap between the fixed scroll 1 and the swinging scroll 2 in the radial direction.

In the conventional scroll compressor configured as described above, when the motor stator 19 is energized, the rotor 20 generates torque and the crankshaft 1
Rotates together with 4. When the crankshaft 14 rotates, rotational force is transmitted to the oscillating scroll shaft 4 which is eccentrically connected to the crankshaft 14, and the oscillating scroll 2 performs a rotational movement around the axis of the crankshaft 14 while being guided by the Oldham joint 11. , performs the compression action shown in FIG. Along with this, gas is sucked into the suction chamber 6 from the suction hole 7, taken into the compression chamber 5, and is sequentially compressed and sent into the inner discharge chamber 8 by the orbiting movement of the oscillating scroll 2, and then fixed. Discharge hole 8a in the center of scroll 1
It is discharged from.

Note that the orbiting motion of the oscillating scroll 2 accompanying the rotation of the crankshaft 14 tends to cause vibrations due to unbalance in the entire compressor, but the first balance member 21 and the second balance member 22
4, the centrifugal force component caused by the orbiting motion of the oscillating scroll 2 is statically and dynamically offset, and balance is maintained around the crankshaft 14, resulting in the compressor generating abnormal vibrations. It is driven without doing anything.

In the conventional compressor as described above, the oscillating scroll 2 performs an orbiting motion drawing a circle with a radius r,
Although it comes closest to the fixed scroll 1 in the eccentric direction, a gap C in the radial direction is created between the two spirals in order to allow the swinging scroll 2 to orbit smoothly. The existence of such a radial gap C makes it difficult to seal the radial gap in the compression chamber 5, and gas inside the compression chamber 5 leaks to the low pressure side through the radial gap C. become. When the gas inside the compression chamber 5 leaks to the low pressure side, the amount of gas finally discharged from the discharge hole 8a decreases, that is, the volumetric efficiency decreases, or the leaked gas may be compressed again. This leads to the problem that the motor input increases and the so-called coefficient of performance decreases. Furthermore, if the eccentricity r is set so that the radial gap C becomes 0, excessive force may be applied to the swing bearing 16 and the main bearing 17 depending on the shape accuracy of the fixed scroll 1 and the swing scroll 2. There was also a risk of burn-in.

This invention was made in order to eliminate the above-mentioned conventional drawbacks, and the eccentricity r of the oscillating scroll shaft, which is movable in the radial direction and eccentric from the crankshaft, is variable, and when the oscillating scroll rotates, The oscillating scroll is pressed against the fixed scroll by the combined force of the gas load and the centrifugal force, and the operating state is such that the gap c between these scrolls is always zero. The purpose is to provide a highly reliable scroll compressor.

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

FIGS. 5 and 6 show an example of a scroll compressor according to the present invention, and the same or corresponding parts as in FIGS. 2 to 4 are given the same reference numerals, and the explanation thereof will be omitted. Further, in the figure, 26 is a bearing fitting hole formed eccentrically from the axis O of the upper end surface of the crankshaft 14, and the bearing fitting hole 26 has a long length extending in a direction away from the diameter of the crankshaft 14. The swing bearing 16 is fitted into the bearing fitting hole 26 so as to be slidable in the longitudinal direction but not rotated. An oscillating scroll shaft 4 protruding from the lower surface of the plate 3 is rotatably fitted. Further, α is the angle formed between the longitudinal direction of the bearing fitting hole 26 and the eccentric direction of the rocking bearing 16, and θ is the angle formed between the resultant force F of the centrifugal force Fc and the gas load Fg and the eccentric direction.

In addition, in such a scroll compressor, the rotation speed is generally constant, so the magnitude of the centrifugal force Fc is always constant, but the magnitude of the gas load Fg depends on the operating conditions, such as the pressure of the suction gas or the discharge gas. It changes to some extent depending on the pressure. Therefore centrifugal force
The magnitude of the resultant force F of Fc and gas load Fg also changes,
The angle θ formed by the resultant force F also changes within a certain range. In the embodiment shown in FIG. 5, the angle between the resultant force F at the maximum allowable gas load and the longitudinal direction of the bearing fitting hole 26 is selected to be 90 degrees.

In the scroll compressor of this embodiment configured as described above, under normal operating conditions, the gas load is
Since Fg is not so large, the angle (α+θ) between the resultant force F and the longitudinal direction of the fitting hole 26 is smaller than 90°. Therefore, during operation, the resultant force F is applied to the swing bearing 1.
6, a component force F' of the resultant force F is applied to the swing bearing 1.
6 in the longitudinal direction of the fitting hole 26. The magnitude of the component force F' at this time is expressed as F'=Fcos(α+θ)...(1). When the component force F′ shown in equation (1) is generated,
The swing bearing 16 slides in the fitting hole 26 in a direction in which the swing radius r increases, and stops at a position where the swing scroll 2 contacts the fixed scroll 1. Therefore, even if the shape accuracy of both scrolls is poor, the oscillating scroll 2 can follow the fixed scroll 1 while
That is, since the rotating movement is performed while freely changing the swing radius r, the radial gap C is always maintained at zero. Therefore, the radial gap C between the fixed scroll 1 and the oscillating scroll 2 is sufficiently sealed, and gas leakage is reduced, resulting in improved volumetric efficiency of the compressor and reduced leakage. Since less gas is recompressed, motor input is reduced and the coefficient of performance is improved.

In this case, the contact load F'' between the fixed scroll 1 and the oscillating scroll 2 is F''=F'cosα=Fcosαcos(α+θ)...(2), which is a very small load compared to the resultant force F. be. Therefore, even if the fixed scroll 1 and the oscillating scroll 2 come into contact, the contact load is small, so
Problems with surface wear and seizure are less likely to occur.

Furthermore, if the operating conditions change and the gas load Fg exceeds the allowable value, the angle (α + θ) between the resultant force F and the longitudinal direction of the fitting hole 26 will exceed 90°; , the direction of the component force F' of the resultant force F is opposite to that in normal operation, and acts in a direction that reduces the amount of eccentricity r. Therefore, the radial gap C becomes larger, and therefore the amount of gas leaking from the compression chamber 5 increases, that is, unloading occurs. Furthermore, even if refrigerant liquid or oil is taken into the compression chamber 5, the radial gap C increases and the refrigerant is unloaded, thereby protecting the compressor from overload.

The sliding direction of the swing bearing 16 is set to the crankshaft 14.
The gas load Fg in the compression chamber is set at a predetermined angle with the eccentric direction of the axis of the rocking bearing 16 with respect to the axis of and the centrifugal force Fc acting in the eccentric direction of the rocking bearing 16, and the component force F' in the sliding direction of the resultant force F causes the rocking bearing 16 to rotate so that the spiral of the rocking scroll 2 becomes the spiral of the fixed scroll 1. Since it is configured to slide in the direction that allows it to approach and separate, the sliding movement of the swing bearing ensures that the gap between the swing scroll and the fixed scroll is always zero, and the distance between the scrolls is ensured. A sealed operating condition can be obtained, which has the effect of providing a high-performance and highly reliable scroll compressor.

Moreover, as mentioned above, since the swing bearing is caused to slide by a component of the combined force of the gas load and centrifugal force, there is no need for any additional members for the sliding movement, and the configuration is therefore simple. This also has the effect of suppressing cost increases.

[Brief explanation of drawings]

Figures 1 a to d are diagrams of the operating principle of a scroll compressor, Figure 2 is a cross-sectional view showing the overall configuration of a conventional scroll compressor, and Figure 3 is an enlarged cross-sectional view showing details of a conventional rocking bearing part. FIG. 4 is an enlarged cross-sectional view showing details of the conventional swing bearing and scroll portion, and FIG. 5 is a cross-sectional view showing details of the swing bearing portion of the scroll compressor of the present invention.
FIG. 6 is a sectional view showing details of the swing bearing and the scroll portion of the scroll compressor of the present invention. 1... Fixed scroll, 2... Oscillating scroll, 3
... Base plate, 4... Oscillating scroll shaft, 5... Compression chamber, 6
...Suction chamber, 8...Discharge chamber, 10...Bearing support, 11...
Oldham joint, 14...crankshaft, 16...swing bearing, 17...main bearing, 19...motor stator, 20
...Motor rotor, 21, 22...Balance member, 2
3... Shell, 26... Bearing fitting hole. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A fixed scroll 1 and an oscillating scroll 2 that form a compression chamber by combining spirals whose winding direction is the same but out of phase by 180 degrees, and an oscillating scroll shaft on the opposite side of the volute of the oscillating scroll. a crankshaft 14 that supports the scroll scroll 4 via a swing bearing 16 provided eccentrically by a predetermined amount and swings the swing scroll; a bearing support 10 that supports the crankshaft via a main bearing 17; The oscillating scroll 2 is provided with an Oldham joint that prevents the oscillating scroll 2 from rotating around the oscillating scroll shaft 4 and allows the oscillating scroll 2 to oscillate around the main bearing, and a motor that drives the crankshaft 14. swing bearing 1
In a scroll compressor in which 6 is slidably mounted in a plane perpendicular to the axis of the crankshaft 14, the sliding direction of the oscillating bearing 16 is set so that the axial center of the oscillating bearing 16 is relative to the axial center of the crankshaft 14. is set at a predetermined angle with respect to the eccentric direction of the rocking bearing 16, and acts in a direction substantially perpendicular to the eccentric direction of the rocking bearing 16, and acts on the gas load Fg in the compression chamber, which changes depending on operating conditions, and in the eccentric direction of the rocking bearing 16. A component force F' in the sliding direction of the resultant force F with the centrifugal force Fc causes the swing bearing 16 to slide in a direction in which the spiral of the swing scroll 2 can approach and separate from the spiral of the fixed scroll 1. A scroll compressor characterized by: