JPS59221401A - Gas spring controller of free piston engine - Google Patents

Abstract

PURPOSE:To make a power loss small by eliminating the deviation of a free piston and enabling to vary mean pressure of a gas spring, by providing a suction valve or a discharge valve in a gas spring chamber, in a free piston engine. CONSTITUTION:Suction valves 25, 26 are provided in a right and left gas spring chambers 13, 22, in a free piston engine consisting of a free piston 15 moving in a reciprocating state, a bearing supporting the free piston and a gas spring for making the free piston 15 resonate. Suction ports of these suction valves 25, 26 are connected with a container 27. Hereupon, as for the suction valves 25, 26, simple structure ones such as the suction valve and a discharge valve being used for a conventional compressor are enough. The valve may be provided directly on cylinders 4, 5 without making use of pipes. The suction valves 25, 26 are so constituted that gas is sent into the gas spring chambers 13, 22 from the container 27 only when pressure of the gas spring chambers 13, 22 is lower than that of the container 27. Minimum pressure, therefore, of the chambers 13, 22 become identical with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a free piston engine, and more particularly to a gas spring control device suitable for reducing power loss of a gas spring.

[Background of the invention]

Free piston engines are broadly divided into compressors and engines, but both have the same problem regarding gas springs. Therefore, although the present invention is applicable to both,
Here, the compressor will be explained.

Figure 1 is a sectional view of the entire free piston type vibratory compressor. The stator 2 of the vibration motor is installed in the motor housing 1.
A bearing 3, a gas spring cylinder 4, a compression chamber cylinder 5, and a cylinder head 6 are installed symmetrically on both sides. The free piston 15 has a structure in which a shaft 8, a gas spring piston 9, a compression screw, and a ton LO are attached symmetrically to both sides of the plunger 7 of the vibration motor. The gas spring piston 9 and the compression piston 10 are provided with piston rings 11, . 12 is installation.

When the vibration motor is energized, the granger 7 is vibrated left and right at the power supply frequency. When the natural frequency of the mechanical vibration system consisting of the free piston 15 and the gas springs 13 and 14 on both sides is approximately equal to the excitation frequency, the free piston is in a resonant state. is compressed and discharged in the compression chamber, and discharged into the discharge boat 17.
flows to In FIG. 1, suction gas flows through boat 18 to cool the vibration motor before flowing into suction boat 16. In FIG. In a vibratory compressor that operates in this manner, the free piston/15 may shift to one side due to an imbalance in the average pressures of the left and right gas springs 13,14. If the free piston 15 is operated with it biased to one side, the piston stroke must be made small, resulting in a decrease in efficiency, and in severe cases, no compression action is performed. In this way, it is an important issue to equalize the average pressures of the gas springs 13, 14.

In the prior art, the free piston is prevented from shifting by a method as shown in FIG. Figure 2 shows only the gas spring section, and when the reel and free piston are near the center position, the gas spring chamber 13 on the right side is connected to the pipe 19.
, communicates with the inside of the free piston cylinder 21 through the communication hole 20 of the gas spring piston, and the gas spring chamber 22 on the left side also communicates with the pipe 23,
It communicates with the inside of the free piston cylinder 21 via the communication hole 24. Therefore, when the free piston 15 moves to the center position, the left and right gas spring chambers 13.22
The pressure is equal to the pressure 21 of the free piston circle f1. However, when the free piston 15 moves slightly from the center position, even though the pressures in the left and right gas spring chambers 13.22 are different, the pipes 19, 23 and the communication hole 20
24 are in communication, gas flow occurs between these pipes and the communication holes. If there is a gas leak between the piston and cylinder in the gas spring chamber, the pressure in the left and right gas spring chambers 13.22 will change with hysteresis, so even if the free piston 15 is in the center position, the left and right gas The pressures in the spring chambers 13.22 are not equal. In such a case, the flow of gas in the pipes 19, 23 and the communication holes 20.degree. 23 becomes even greater. This gas flow results in power loss in the gas spring.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas spring control device that completely eliminates the bias of a free piston, and that has a gas spring that can change the average pressure of the gas spring and that has a small power loss.

[Summary of the invention]

The conventional thinking is that the pressure in the gas spring chamber fluctuates,
The average pressure (when the free piston is in the center position) is directly used to prevent the free piston from shifting. The average pressure in the gas spring chamber can be determined from the minimum value of the fluctuating pressure.

The present invention can achieve the object of the present invention by utilizing this minimum pressure and minimizing the total flow and flow of gas in the gas spring chamber.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

Suction valves 25.2 are installed in the left and right gas spring chambers 13.22.
6 is a provision. The suction ports of these suction valves 25 and 26 are connected to the container 27. Here, the suction valve 25
．． For 26, a simple structure such as a suction valve or a discharge valve used in a general compressor is sufficient. or,
It is also possible to provide the cylinder 4.5 directly without using a pipe.

The suction valves 25, 26 allow gas to enter the container 27 only if the pressure in the gas spring chamber 13.22 is lower than the pressure in the container 27.
The gas is supplied from the gas spring chamber 13.22. Therefore, the left and right gas spring chambers 13.2
The two minimum pressures will be equal. Figure 4 shows the left and right gas spring chambers 13.2 when the free piston is not biased.
2 shows the pressure change. a-1) is the pressure change in the gas spring chamber 13 on the right side, and c-d is the pressure change in the gas spring chamber 22 on the pressure side. a-1) (
! : At C-d, due to the effect of the suction valves 25, 26, the pressures at a and C become equal at Pl. Since the pressure changes in the left and right gas spring chambers 13.22 are designed to be symmetrical as shown in the figure, the average pressure of a - S and c - L
The average pressure of d becomes approximately equal at P2.

When the free piston 15 shifts to the right side, the pressure in the left and right gas spring chambers 13.22 becomes e-
It will look like 19g-h. Here, due to the action of the suction valve,
The pressures of and g are equal at Pl. However, since the volume of the gas spring chamber 13 on the right side is small, the pressure fluctuation becomes large as e − f, and the average pressure is P3
become.

On the other hand, since the volume of the left gas spring chamber 22 becomes larger, the pressure fluctuation becomes smaller as gh, and the average pressure becomes P4. Since PsaP4 is also larger, the Sibley piston 15 is pushed to the left by this differential pressure.
Try to suppress all bias. Conversely, when the free piston 15 shifts to the right, the free piston 5 is pushed to the right. In this manner, the action of the suction valves 25 and 26 can prevent the shift free piston 15 from shifting to one side. In addition, when the free piston 15 is vibrating with no bias, the pressure in the left and right gas spring chambers 13°22 and the pressure in the container 2
Since the pressures at 7 are equal, no gas flow occurs through the suction valves 25 and 26.

FIG. 6 shows another embodiment of the invention, in which a filter is provided in one discharge valve 28, 29' of the one in FIG. A flow control valve 31 is provided to allow a certain amount of gas to flow out. FIG. 6 shows an example in which a gas bearing is used as the bearing 13. Since the high-pressure gas for the bearing is supplied from the boat 32, it flows into the gas spring chamber 13 through the bearing gap, so that the pressure in the gas spring chamber 13.22 increases. Therefore, since the free piston deviates from the resonant state, the amplitude becomes smaller. Therefore, if the opening degree of the flow control valve 31 is adjusted and the amount of gas that leaks from the bearing 13 flows out of the container, the pressure inside the gas spring chamber will not increase.
The Reapist/15 can be maintained in a resonant state.

The discharge valve 28.29 here prevents a backflow from the container 31 into the gas spring chamber 13.22, so that power losses in the gas spring due to gas flow are minimized. By changing the flow rate control valve 31 in this way, it is possible to maintain the resonance condition W+, and when the load becomes small and the amplitude of the free piston 15 increases, the average pressure in the gas spring chamber 13.22 is increased, and the resonance condition is increased. Shift from the state,
Any increase in amplitude can be completely prevented.

The case where gas flows into the gas spring chamber has been explained using FIG. If all pouring methods are employed, the amplitude of the free piston 15 can be fully controlled.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to equalize the average pressure in the gas tin ring chamber, and also to change the equalized average pressure, which greatly reduces loss due to gas flow. Therefore, power loss at the gas spring portion can be reduced.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the entire free piston type vibratory compressor.
Fig. 2 is a cross-sectional view of a gas spring section according to the prior art, Fig. 3 is a cross-sectional view of a gas spring section according to an embodiment of the present invention, and Fig. 4 is a diagram showing pressure changes in the gas spring chamber with respect to the piston stroke. , FIG. 5 is a diagram showing the pressure change in the gas spring chamber with respect to the piston stroke, and FIG. 6 is a sectional view of the gas spring portion showing another embodiment according to the present invention. 13.22... Gas spring chamber, 25.26...
Suction valve for gas spring, 28, 2.9...Discharge valve for gas spring, 31...Flow control valve. ￥J Z Figure 3 Figure 7 and Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. In a free piston engine consisting of a reciprocating free piston, a bearing supporting the free piston, and a gas spring for resonating the free piston, a suction valve or a discharge valve is provided in the gas spring chamber. Gas spring control device for free piston engine with all features. 2. A free piston according to claim 1, characterized in that two or more gas spring chambers are each provided with a suction valve, and the inlets of these suction valves are connected to equalize the inlet pressure of each suction valve. Engine gas spring control device. 3. A gas spring control device for a free piston engine according to claim 1, characterized in that a flow control valve is provided at the outlet of the discharge valve. 4. A gas spring control device for a free piston engine according to claim 2, characterized in that a flow control valve is provided at the inlet of the suction valve.