JPS61258988A - Rotary piston compressor - Google Patents

Abstract

PURPOSE:To enable to offset asymmetric loads working on a drive shaft by equipping a single rotary shaft with rotary piston parts in odd number quantities of three or greater with each rotary piston part having 180 deg. phase difference in the rotary direction and performing simultaneous compression strokes. CONSTITUTION:Rotary piston parts 21, 22 and 23 are rotatably supported over large diameter eccentric shaft parts 30a, 30b and 30c formed on a drive shaft 30. The eccentric shaft parts 30a and 30c are arranged such that their eccentric centers are displaced by 180 deg. in rotary direction of the drive shaft 30 against the eccentric shaft part 30b, namely with each neighboring part having a phase difference of 180 deg.. Vanes 27, 28 and 29 are respectively arranged at different positions according to the phase difference of the eccentric shaft parts 30a, 30b and 30c. With this constitution, asymmetric loads supporting the rotary piston parts 21, 22 and 23 and working on the drive shaft 30 can be offset on the drive shaft 30. Since moments can also be offset, loads on the shaft can be considerably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in a rotary piston compressor, and more particularly to a compressor having a structure that reduces the axial load on the drive shaft of the rotary piston.

<Prior Art> A conventional rotary piston compressor is shown in FIG. 6, for example (Japanese Utility Model Publication No. 58-137892).

This is a configuration in which the rotary piston 1 is discharged once every 201 rotations of the shaft, and the rotary piston 1 is rotatably supported by an eccentric portion 4 formed in a large diameter of the shaft 1 via a bearing 3, and the shaft 2 is It is supported by a main bearing 5.6 in the side wall 7.8 of the cylinder body. Each bearing is provided with an oil supply path 9 for supplying lubricating oil. Further, a balance weight 10.11 is arranged in the cavity inside the rotary piston l and attached to the shaft 2. In the figure, 12 is an oil pump, 13 is an oil cooler, and 14 is an oil liquid recovery tank.

<Problems to be solved by the invention> In the rotary piston type compressor as described above, it is effective to increase the compression ratio in order to obtain larger discharge pressure and discharge amount for a given cylinder diameter. be. Generally, in order to increase the compression ratio, the entire surface of the rotating piston is used to discharge fluid once per revolution.

According to this configuration, when the piston rotates and compresses the gas, as the compression progresses, a large pressure acts on the rotating piston, and this pressure is not applied all the way around the rotating piston, but partially. Since a biased pressure acts on the shaft, a force perpendicular to the shaft acts on the shaft via the rotating piston, and this force is applied to the bearing.

Therefore, the shaft load increases in proportion to the discharge pressure and discharge amount. When the shaft load is large, forced hydraulic fluid lubrication is generally adopted for the bearing, and the forced lubrication device and oil cooling device (oil pump 12, oil cooler 13, oil supply path 9, oil recovery tank) as shown in Fig. 6 are used. 14 etc.), the weight and volume of the compressor increases, and there are problems in that the compressor becomes more complicated.

The present invention aims to solve the above problems by providing a rotary piston type compressor that can reduce the axial load.

Means for Solving the Problems〉 Referring to FIG. 1 showing one embodiment, the means according to the present invention is that in a rotary piston type compressor, an odd number of three or more (Three in the figure) rotating piston parts (21, 22, 23) are provided, and adjacent ones of the rotating piston parts are eccentrically centered (e,
e2, e3) in the rotational direction of the drive shaft (30).
The rotary piston portion (2
A cylinder portion (24, 25, 26) is attached to each of the rotating pistons so that each of the cylinder portions (24, 22, 23) independently performs a compression action.
), and the positions of the respective vanes (27, 28, two) are determined so as to simultaneously perform a compression action.

According to this means, the rotating piston part rotates 180 degrees in the rotational direction.
Since the compressor has a phase difference of 100 degrees and compresses at the same time, the forces exerted by the compressed gas in the respective compression chambers act in directions that cancel each other out within the drive shaft. Further, since the structure includes an odd number of three or more rotary piston parts, the monotonic forces caused by unbalanced loads acting perpendicularly to the drive shaft also act so as to cancel each other out.

These points will be explained using FIGS. 3 to 5. First, consider the direction of the force exerted by the compressed gas. For example, a cylinder part 24 having a vane 27, a suction port 15, and a discharge port 16 in the upper part as shown on the left side of FIG. 3(a)
One has a rotating piston part 21 inside, and the other has a vane 28 at the bottom, a suction port 17, as shown on the right side of the figure.
A rotary piston part 2 is installed in a cylinder 25 provided with a discharge port 18.
The rotary piston parts 21 and 22 are provided adjacently with the same drive shaft 60.
Suppose that they are provided with a phase difference of 180 degrees in the rotational direction. That is, from only the positional relationship seen in the axial direction, they are provided as shown in FIG. 4. In the state shown in FIG. 3 (al), suction and discharge have almost been completed.

When the drive shaft 30 rotates 90 degrees, the respective compression chambers 19a,
19'bO Due to the increase in pressure by 1, the rotating piston part 21.
A group of arrows 50a150 is shown on the surface facing each of the 22 compression chambers.
Arrow g from inside of piston 2 part 21.22
Forces as shown by 1a and 51b come to act. When the rotating shaft 60 further rotates 180 degrees from the initial state, the rotating piston portion 2 rotates as shown in FIG. 3(C).
The pressure acting on the 1°220 surface and the drive shaft 6
The force acting on ° is the group of arrows 52a, 52b, 53a.
, 53b Te changes as shown, and when further rotated 270 degrees from the initial state, the arrow group 54a,
54b, 55a.

It changes as shown by 55'b. Note that each arrow indicates the magnitude and direction of force. The direction of the arrow group shown in Fig. 3 indicates the rotational position of the rotating piston portion 21, 22 (in the same figure)
, (C), and (d), the directions are always opposite between those on the left and those on the right, respectively. Therefore, by providing a plurality of rotary piston parts on the same axis with a phase difference of 180 degrees in the rotational direction, it is possible to cancel out the forces acting on the shaft due to the compression action.

Next, consider the moment due to the force acting on this axis. For example, as shown in FIG.
A shaft 30 having a rotating piston part 23 in the same phase as 1 is supported by a main bearing 34.35, and each rotating piston part 21.22
．． Let the spacing dimensions of 23 be a work, a2, and the forces acting on the shaft due to the aforementioned compression action of each rotary piston part 21, 22, and 23 be F work, F2, and F3, and these forces F work, F2,
Consider the moment generated on the shaft due to F3. Based on the piston part 22, the moment M22 is M22 =
F1x alF3 x a2, and this moment M
Since it is desirable that M22 is small, M22 ”
All you have to do is decide F, F2 and a, a2 so that O.For simplicity, if a and a2 are made equal, then F
By setting M=F3, M22=o. That is, the rotary piston parts 21 and 23 may be formed in the same manner. And since the force F, F2, and F3 need to have sizes that cancel each other out as mentioned above, F2=
Must be F□10F3. Therefore, since F2 must be twice as large as F0 or F2, simply the width of the rotating piston portion 22 can be twice the width of the other 21 or 23, and the other dimensions can be made the same. This can be illustrated using the above-mentioned symbols as shown in FIG. 5(1)+. That is, the intervals between the rotating piston parts 21, 22, and 23 are
Rotating screw! - If the width of the rotary piston portion 21.23 is e, the width of the rotary piston portion 22 is 2e, and each rotary piston portion 21.22.
The outer diameter and other dimensions of 23 are the same. In the figure, 29 is a vane of the rotating piston portion 23. In the one shown in FIG. 5('b), each rotary piston portion 21.2 is attached to the drive shaft 3o.
The forces acting due to the compression action of 2.23, that is, the unbalanced loads, cancel each other out at 3 degrees above the drive shaft, and their moments also cancel each other out. Only a weight of .22.23 will come into play.

Note that the reason why the number of rotating piston parts is set to an odd number of 3 or more is to take into account the cancellation of the moments described above, and the same effect can be obtained even if the number is set to 5.7.

Example of implementation> In Figures 1 and 2, 21.22.23 is the rotating piston part, 24.25.26 is the cylinder part, and 27.28 is the rotary piston part.
．． 29 is a vane.

In this example three rotating piston parts 21.22.23
, each of which is rotatably driven by one drive shaft 3o. Rotating piston part 21
Each width dimension W of 122.23, W2, W3 is W2:
It is decided that W yo + W 3, W yo d W 3. Each transmission piston part 21, 22, 23 is rotatably supported by a large diameter eccentric shaft part 30a, 301), 300 formed on the drive shaft 30. The eccentric shaft portions 30a, 30'k
), 300 are determined to be equal, and the eccentric shaft portions 3Qa and 30C have their eccentric centers rotationally displaced by 180 degrees in the rotational direction of the drive shaft 3o with respect to the eccentric shaft 130b, that is, the eccentric shaft portions 3Qa and 30C are adjacent to each other. The brooms are set so that the objects are 180 degrees different from each other in ζ6 phase. The drive shaft 3o has both ends rotatably supported by the outer side wall parts 32.33 of the cylinder parts 24.26 at both ends via main bearings 34.35, and a rotational drive source is coupled to one end. There is.

The cylinder portions 27, 28, and 2 are arranged on side walls 36, 37 so that they each independently perform suction, compression, and discharge functions.
．． 38, 39, mounted with vanes 27, 28, 29, and provided with an inlet and an outlet (not shown).

Each of the vanes 27, 28, 29 is placed in a position in which it moves forward and backward relative to the respective rotary piston portions 21.22.23 at the same time, that is, so that the rotary piston portions 21.22.23 always perform a compression action at the same time. Eccentric shaft portions 30a, 30'b
, 300 at different positions depending on the phase difference between the two.

The figure shows the state in which each vane 27, 28, 29 is most protruded towards the circumferential surface of the corresponding rotary piston part 21, 22, 23. In the figure, 40, 41, and 42 are springs for pushing out the vane.

<Effects of the Invention> According to the present invention, the uneven load acting on the drive shaft supporting the rotating piston due to the uneven pressure generated in the gas compression process is reduced.
Since it can be canceled out on the drive shaft and the moment due to the unbalanced load can be canceled out, it is possible to use a rotating piston type compression in which the unbalanced load due to the gas compression action does not act on the main bearing of the drive shaft. The structure of the bearing can be simplified, for example, it is possible to use a grease-sealed bearing or a dry bearing, and there is no need for an oil circulation or cooling device for the main bearing, allowing for miniaturization and surface area reduction. Further, the structure does not require a special provision of a balance weight, and in this respect it is also possible to reduce the weight, and furthermore, it is possible to obtain the effect that vibrations caused by rotation of the eccentric rotary piston portion are reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view perpendicular to the cylinder axis showing the main longitudinal front cylinder part and its internal state at different rotational positions of the drive shaft 30 of an embodiment of the present invention, and FIG. 4 is a detailed view of the present invention. FIG. 6 is a partial longitudinal sectional front view showing an example of a conventional rotary piston type compressor. 21.22.23... Rotating piston part, 24.25.
26... Cylinder part, 27.28.29... Vane, 3o... Drive shaft. Patent applicant Nippon Air Brake Co., Ltd. Representative Tetsu Shimizu and 2 others'''

Claims (1)

[Claims] (1) In a rotary piston type compressor, an odd number of three or more rotary piston parts are provided for one rotary drive shaft, and adjacent ones of the rotary piston parts have their eccentric centers aligned in the direction of rotation of the drive shaft. The rotary piston parts are provided with a 180 degree phase shift, and each of the rotary piston parts is provided with a cylinder part so that each of the rotary piston parts independently performs a compression action, and the positions of the respective vanes are adjusted so that they simultaneously perform a compression action. A rotary piston type compressor characterized by: