JPH051503A - Scroll type fluid machine - Google Patents

Abstract

PURPOSE:To prevent a large diametric load applied to an auxiliary crank when an end plate or the like at a rotary scroll is thermally expanded, and improve the life of the auxiliary crank, a bearing, etc. CONSTITUTION:A side shaft part 21B of an auxiliary crank 21 is composed of a hollow shaft main body 22, a rubber cylinder 23 covering an outer circumferential surface of the shaft main body 22, and a metal cylinder 24 covering an outer circumferential surface of the rubber cylinder 24. When a rotary scroll 5 is thermally expanded diametrically, the rubber cylinder 23 of the auxiliary crank 21 is elastically deformed to apply a distance (d) between the metal cylinder 24 and one side shaft part 21A to a size change of the rotary scroll 5, thereby a large load in the direction of an arrow A applied on the auxiliary crank 21 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type fluid machine suitable for use in, for example, an air compressor or a vacuum pump, and more particularly to a scroll type fluid machine provided with an auxiliary crank as a rotation preventing mechanism.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show an oilless scroll type air compressor as an example of a scroll type fluid machine according to the prior art.

In the figure, reference numeral 1 denotes a stepped cylindrical casing, which is a large diameter cylindrical portion 1A and a large diameter cylindrical portion 1
The large-diameter cylindrical portion is roughly composed of a bearing portion 1B projecting from the inner peripheral side of A toward one side in the axial direction and a flange portion 1C integrally formed on the other end side of the large-diameter cylindrical portion 1A. On the inner peripheral side of 1A, three bearing accommodating portions 1D (only one is shown) formed to project inward in the radial direction are slidably contacted with the rear surface of the orbiting scroll 5 described later to receive a load in the thrust direction. The thrust receiving portion 1E is formed.

Reference numeral 2 denotes a bearing 3 in a bearing portion 1B of the casing 1.
4 shows a drive shaft that is rotatably supported via a drive shaft 2. The front end side of the drive shaft 2 extends into the large-diameter cylindrical portion 1A of the casing 1 to form a crank 2A, and the axis of the crank 2A is the drive shaft. It is eccentric by a predetermined dimension d with respect to the axis of 2. The base end side of the drive shaft 2 projects outward from the bearing portion 1B of the casing 1, is connected to an electric motor (neither is shown) via a pulley, and is rotationally driven by the electric motor. It is something.

Reference numeral 5 denotes an orbiting scroll which is located inside the casing 1 and is provided on the crank 2A of the drive shaft 2 so as to be able to orbit. The orbiting scroll 5 is a disk-shaped end plate 5A and the end plate 5A. A spirally wrapped wrap portion 5 that is provided upright with the center side as the winding start end and the outer peripheral side as the winding end end.
B and a boss portion 5C provided at the center of the rear surface of the end plate 5A. The crank 2A of the drive shaft 2 is mounted in the boss portion 5C via a swivel bearing 6. Further, three bearing housing holes 5D (only one is shown) for housing another side auxiliary crank bearing 11, which will be described later, are formed on the outer peripheral side of the rear surface of the end plate 5A.

Reference numeral 7 denotes a fixed scroll facing the orbiting scroll 5 and fixed to the other end side of the large-diameter cylindrical portion 1A of the casing 1 through a mounting bolt (not shown). The mirror plate 7A is arranged in the central portion so as to coincide with the axis of the drive shaft 2, and a spiral wrap portion 7B is provided upright from the mirror plate 7A in the same manner as the wrap portion 5B of the orbiting scroll 5. On the one end face side of the fixed scroll 7, a cylindrical thrust receiving portion 7C located radially outside the wrap portion 7B and slidingly contacting the end plate 5A of the orbiting scroll 5 to receive the load in the thrust direction. Are formed.

Here, the wrap portion 7 of the fixed scroll 7
B is arranged so as to overlap with the wrap portion 5B of the orbiting scroll 5 by a predetermined angle and overlap.
Form a plurality of compression chambers 8 that continuously contract with the wrap portion 5B when the vehicle turns.

Numeral 9 is located between the bearing accommodating portion 1D of the casing 1 and the end plate 5A of the orbiting scroll 5, and is provided with, for example, three auxiliary cranks (only one is shown in the drawing) as a rotation preventing mechanism which are provided in a circumferentially spaced manner. ), The auxiliary crank 9 is
As shown in FIG. 6, the one side shaft portion 9A located on one end side is connected to the bearing housing portion 1D of the casing 1 via the one side auxiliary crank bearing 10 and the other side shaft portion 9B located on the other end side.
Are connected to the bearing housing hole 5D of the orbiting scroll 5 via the other side auxiliary crank bearing 11, and these shaft portions 9A, 9
B is fixed by a crank arm 9C so as to be eccentric by a predetermined axial distance d. The auxiliary crank 9 prevents the orbiting scroll 5 from rotating when the orbiting scroll 5 is imparted with a circular motion having a orbiting radius of d by the rotation of the drive shaft 2, whereby the orbiting scroll 5 is prevented from rotating. The drive shaft 2 is rotated about the axis thereof.

Reference numeral 12 indicates a suction port formed on the outer peripheral side of the fixed scroll 7, and 13 indicates a discharge port formed on the end plate 7A of the fixed scroll 7. The suction port 12 is the outermost peripheral side (minimum pressure side). And the discharge port 13 communicates with the compression chamber 8 on the most central side (highest pressure side). Reference numeral 14 indicates a counter weight fixed to the drive shaft 2, and the counter weight 14 balances the rotation of the drive shaft 2.

The scroll type air compressor according to the prior art has the above-mentioned structure, and when the drive shaft 2 is rotationally driven by the electric motor, this rotation is transmitted from the crank 2A to the orbiting scroll 5 via the orbiting bearing 6. The orbiting scroll 5 is rotated about the axis of the drive shaft 2 while being prevented from rotating by the auxiliary crank 9. Then, by this turning motion, the respective lap portions 5B, 7
The compression chambers 8, 8, ... Defined between B and B are continuously reduced in size, and the air sucked from the suction port 12 is sequentially compressed in each compression chamber 8 while the compressed air is discharged from the discharge port 13. It is discharged to an external air tank etc. to perform compression.

[0011]

By the way, according to the above-mentioned conventional technique, not only the compression heat according to the discharge pressure is generated in each compression chamber 8 at the time of the compression action, but also the friction heat is generated in the orbiting bearing 6. Occurs, the temperature of the orbiting scroll 5 rises due to the heat, and the temperature rise causes the orbiting scroll 5 to undergo a large thermal expansion. Particularly, in the oil-free scroll type air compressor, the orbiting scroll 5 is not cooled by the lubricating oil, so that the thermal expansion due to the temperature rise is remarkable. On the other hand, since the surface of the casing 1 surrounding the outer peripheral side of the orbiting scroll 5 is exposed to the outside air and cooled, the temperature rise is relatively small and the thermal expansion thereof is also small compared to the orbiting scroll 5.

Therefore, in the above-mentioned prior art, since the difference in thermal expansion between the orbiting scroll 5 and the casing 1 is large, the auxiliary crank 9 is moved in the direction of arrow A along with the radial thermal expansion of the orbiting scroll 5. The load acts strongly, which hinders the smooth rotation of the orbiting scroll 5 and significantly increases the power loss, as well as causes a breakage accident in the auxiliary crank 9 and shortens the life of each auxiliary crank bearing 10, 11. However, there is a problem that compression efficiency, durability, and reliability are significantly reduced.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when the orbiting scroll thermally expands in the radial direction due to a temperature rise, it is possible to effectively prevent a load in the radial direction from being applied to the auxiliary crank. It is an object of the present invention to provide a scroll type fluid machine capable of improving reliability and life.

[0014]

In order to solve the above-mentioned problems, the feature of the structure adopted by the present invention is that the axial distance between the one side shaft part and the other side shaft part changes in the auxiliary crank. This is because an elastic member that allows the above is provided.

[0015]

With the above structure, even if the end plate of the orbiting scroll is greatly thermally expanded, the elastic member can absorb the thermal expansion and change the axial distance between the auxiliary cranks, so that the auxiliary cranks receive a large radial load. Can be prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiments, the same components as those of the conventional technique shown in FIGS. 5 and 6 described above are designated by the same reference numerals, and the description thereof will be omitted.

First, FIGS. 1 and 2 show a first embodiment of the present invention.

In the figure, reference numeral 21 denotes an auxiliary crank according to the present embodiment, which is similar to the auxiliary crank 9 according to the prior art, and has one side shaft portion 21A and the other side shaft portion 21B located at one end side. Although the auxiliary crank 21 is fixed via a crank arm 21C so as to be eccentric by a predetermined inter-axis distance d, the auxiliary crank 21 has a solid shaft main body 22 with a second side shaft portion 21B and a solid shaft main body 22 as shown in FIG. A rubber cylinder 23 that covers the outer peripheral surface of the main body 22 and has an inner peripheral side fixed to the shaft main body 22 as an elastic member, and a metal cylinder that covers the outer peripheral surface of the rubber cylinder 23 and the inner peripheral side is fixed to the rubber cylinder 23. And 24.

Here, the rubber tube 23 has a high elasticity and is formed into a cylindrical shape from high-strength rubber, and the shaft body 22 and the metal tube 24 are provided.
They are fixed by using a means such as baking so that these axes are the same between the two.

The auxiliary crank 21 has the other side shaft portion 21.
When a pressing force is applied to the B metal cylinder 24 from the outer peripheral surface side,
The rubber cylinder 23 is elastically deformed in the radial direction to allow the metal cylinder 24 to be slightly displaced in the direction of force.

The scroll type air compressor according to this embodiment has the above-mentioned structure, and its basic operation is not different from that of the prior art.

However, according to the present embodiment, the other side shaft portion 21B of the auxiliary crank 21 is provided with the solid shaft body 22, the rubber cylinder 23 covering the outer peripheral surface of the shaft body 22, and the outer periphery of the rubber cylinder 23. Since it is composed of the metal cylinder 24 covering the surface, the temperature of the orbiting scroll 5 rises due to the compression heat in each compression chamber 8, the orbiting scroll 5 thermally expands in the radial direction, and the auxiliary crank 21
When a load in the direction of arrow A is applied to the rubber cylinder 23 that covers the outer peripheral surface of the shaft body 22 of the other side shaft portion 21B elastically deforms in the direction of arrow A, this load can be absorbed and the auxiliary crank 21 Metal cylinder 24 of one side shaft portion 21A and the other side shaft portion 21B
, The inter-axis distance d between the one-side shaft portion 21A and the other-side shaft portion 21B can be changed according to the thermal expansion amount of the orbiting scroll 5.

Therefore, according to this embodiment, when the orbiting scroll 5 is thermally expanded, the load in the direction of arrow A is applied to the auxiliary crank 21.
Can be reliably prevented from being applied directly to the auxiliary crank bearings 11, and an unbalanced load can be prevented from acting on the one side auxiliary crank bearing 10 and the other side auxiliary crank bearing 11, and the orbiting scroll 5 can be smoothly orbited to assist the auxiliary crank 21. It is possible to effectively prevent breakage accidents, to significantly improve performance such as compression efficiency, durability, and reliability, and to significantly extend the life of each auxiliary crank bearing 10, 11.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that the auxiliary crank 31 is attached to the one side shaft portion 3.
1A, the other side shaft portion 31B, and a crank arm 31C. The other side shaft portion 31B includes a shaft body 32 and a shaft body 3 for fixing the shaft body 32 to the crank arm 31C.
2 and a hard rubber 33 as an elastic member provided at the base end. And the auxiliary crank 31
Allows the hard rubber 33 to elastically deform and move the axis of the other side shaft portion 31B to change the inter-axis distance d between the one side shaft portion 31A and the other side shaft portion 31B.

Thus, in this embodiment having such a structure, it is possible to obtain substantially the same operational effects as those of the first embodiment.

In each of the above embodiments, the auxiliary crank 2
1 (31) is provided between the bearing accommodating portion 1D of the casing 1 and the orbiting scroll 5 as an example.
Instead of this, as in the modification shown in FIG. 4, it may be used in a scroll type air compressor of the type in which an auxiliary crank as a rotation preventing mechanism is provided between the orbiting scroll and the fixed scroll. In FIG. 4, the same components as those described in the first embodiment are designated by the reference numeral “′” and the description thereof will be omitted.

In this case, the one side shaft portion 21A 'of the auxiliary crank 21' is supported by the bearing 41 provided on the end plate 5A 'of the orbiting scroll 5', and the other side shaft portion 21B 'is the outer circumference of the fixed scroll 7'. It may be supported by the bearing 42 provided on the thrust receiving portion 7C ′ or the like located on the side. Further, the one side shaft portion 21A 'may be attached to the thrust receiving portion 7C' and the other side shaft portion 21B 'may be attached to the orbiting scroll 5'side.

Furthermore, in the above embodiment, the other side shaft portion 2
The case where 1B is composed of the shaft body 22, the rubber cylinder 23, and the metal cylinder 24 has been described as an example, but instead of this,
The one-side shaft portion 21A may be composed of a shaft body, a rubber cylinder, and a metal cylinder, and this structure may be applied to both the one-side shaft portion 21A and the other-side shaft portion 21B.

[0029]

As described above in detail, according to the present invention, the auxiliary crank is provided with the elastic member which allows the axial distance between the one side shaft portion and the other side shaft portion to be changed. When the temperature of the orbiting scroll rises due to the compression heat in the compression chamber, and the orbiting scroll undergoes thermal expansion in the radial direction, the elastic member of the auxiliary crank elastically deforms and the shafts of the one side shaft part and the other side shaft part are deformed. The inter-space distance can be adapted to the dimensional change of the orbiting scroll, and a large load can be reliably prevented from acting on the auxiliary crank, and the orbiting scroll can be smoothly orbited and the accident that the auxiliary crank is broken can be effectively prevented. The performance such as compression efficiency, durability, and reliability of the scroll type fluid machine can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged longitudinal sectional view showing a main part of a scroll air compressor according to a first embodiment of the present invention.

FIG. 2 is an enlarged front view of the auxiliary crank shown in FIG.

FIG. 3 is an enlarged front view showing an auxiliary crank according to a second embodiment.

FIG. 4 is a longitudinal sectional view of a main part showing a scroll type air compressor according to a modification.

FIG. 5 is a vertical sectional view showing a scroll type air compressor according to a conventional technique.

6 is an enlarged cross-sectional view showing an enlarged main part in FIG.

[Explanation of symbols]

 1 Casing 2 Drive shaft 2A Crank 5,5 'Orbiting scroll 5B, 5B' Wrap part 7, 7'Fixed scroll 7A, 7A 'End plate 7B, 7B' Wrap part 8, 8 'Compression chamber 21, 21', 31 Auxiliary crank 21A, 21A ', 31A One side shaft part 21B, 21B', 31B Other side shaft part 21C, 21C ', 31C Crank arm 22, 22', 32 Shaft body 23, 23 'Rubber cylinder (elastic member) 24, 24' Metal cylinder 33 Hard rubber (elastic member) d Distance between axes

Claims (1)

Claim: What is claimed is: 1. A cylindrical casing, a drive shaft rotatably provided at one end of the casing, and a distal end extending into the casing to form a crank, and a drive shaft of the drive shaft. An orbiting scroll that is rotatably provided on the crank through a boss portion, and has a spiral wrap portion erected on the end plate, and is fixed to the other end side of the casing so as to face the orbiting scroll and to turn to the end plate. A fixed scroll in which spiral-shaped wrap portions forming a plurality of compression chambers with the wrap portion of the scroll are erected, and one side shaft portion is rotatably connected to the fixed scroll or the casing, and the other side shaft. In a scroll fluid machine, a portion of which is rotatably connected to the orbiting scroll and which includes an auxiliary crank that prevents rotation of the orbiting scroll. Scroll fluid machine in which the center distance between the parts and the other side shaft portion, characterized in that a resilient member to allow the change.