JPS63246452A - Vibration reducing device for stirling engine - Google Patents

Abstract

PURPOSE:To reduce vibration, by generating vibration suppressing force so as to reduce the vibration of a mounting bed, caused by a change of torque in an engine, by an actuator being based on the detection result of pressure in a cylinder chamber through a pressure sensor. CONSTITUTION:A change of pressure in a cylinder chamber is detected by a pressure sensor 18, and a signal of this change of pressure is amplified by a pressure gage 19 to an electric signal, having predetermined voltage, being input to a control circuit 20. The control circuit 20 sets its gain and phase characteristic so that predetermined control regulation is satisfied, that is, so that vibration suppressing force, generated from an actuator 17, negates or reduces a change of torque from a Stirling engine. Accordingly, the control circuit 20 regulates the signal from the pressure sensor 18 for its gain and phase driving the actuator 17 through a driving circuit 21. Vibration suppressing force in a direction of cancelling the change of torque in the engine is generated from the actuator 17 so that a mounting bed 15 reduces its vibration angular displacement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration reduction device for reducing vibrations caused by pressure fluctuations generated in a Stirling engine.

[Conventional technology]

FIG. 8 is a schematic diagram of a conventional Stirling engine disclosed in, for example, Japanese Patent Application Laid-Open No. 60-219438.

In the figure, 1 is a cylinder, 2 is a power piston attached to the cylinder 1, 3 is a piston rod hanging from the power piston 2, and 4 is fixed to the piston rod 3 on the inner diameter side and to the seal fixture 5 on the outer diameter side. 7 is a crosshead connected to the piston rod 3, 6 is a guide to the cross that guides the movement of the crosshead 7, and 8 is a connecting rod that connects the crosshead 7 and the crankshaft 12. . In addition, 10 is the crankshaft 12
A bearing 13 supports the bearing 10. A lubricating oil for lubricating mechanical parts such as the crosshead 7, 11 a mechanical seal attached to the crankshaft 12, and 9 a mechanical seal attached to the crankshaft 12.
Bearing 10. Mechanical seal 11. A crankcase stores lubricating oil 13 and the like, 14 is a buffer tank connected to a buffer chamber 102, and 101 is a cylinder chamber. Although not shown, a displacer piston is provided above the power piston 2 and moves up and down within the cylinder 1 coaxially with the power piston 2.

Next, the operation will be explained. A working substance with a small molecular weight such as helium is sealed in a cylinder chamber 101 inside the cylinder 1, and when a displacer piston (not shown) moves up and down, and when the working fluid receives heat energy from the outside, this cylinder The pressure PA of the working fluid in the chamber 101 fluctuates periodically (detailed explanation of this effect will be omitted), while the pressure PB in the buffer chamber 102 is kept almost constant by the action of the buffer tank 14. .

In the Stirling engine having such a configuration, a pressure difference Δp <-PA-PB) is generated between the cylinder chamber 101 and the buffer chamber 102 by receiving thermal energy from the outside, and this pressure difference is applied to the power piston 2 inside the cylinder. act. This pressure difference ΔP acts on the piston rod 3 as an axial force, is transmitted to the crosshead 7 as a reciprocating motion, and is further transmitted to the connecting rod 8. This is converted into rotational motion by the crankshaft 12 and taken out as power. In this way, the Stirling engine is a closed-cycle reciprocating external combustion engine with multiple pistons and no valves, and it operates by heating and cooling the working gas sealed inside the engine via a heat exchanger. , it is configured to extract power.

[Problem that the invention seeks to solve]

Since the conventional Stirling engine is configured as described above, the pressure acting on the power piston in the cylinder chamber fluctuates, and this pressure fluctuation acts as a change in axial force. 7. As mentioned above, the axial force of the lever is converted into rotational torque around the crankshaft, so the pressure fluctuations acting on the piston appear as torque fluctuations around the crankshaft, causing the Stirling engine body to vibrate around the crankshaft. It acts to cause

In order to improve the energy conversion efficiency of the Stirling engine, it is necessary to make the enclosed working gas high pressure, but if the working gas is made high pressure, the torque fluctuation will increase accordingly, and the Stirling engine The vibration of the engine also increases, causing a decrease in the quietness of the engine and a decrease in reliability.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain a vibration reduction device for a Stirling engine that can reduce vibrations caused by torque fluctuations generated by the Stirling engine. do.

[Means for solving problems]

The vibration reduction device for a Stirling engine according to the present invention includes an actuator that is attached to a pedestal to which the Stirling engine is fixed and generates an allocation force according to an external drive control signal, and an actuator that detects the pressure inside the cylinder chamber of the engine to reduce the pressure. The engine is equipped with a pressure sensor that outputs a signal, and a control circuit that drives and controls the actuator based on the pressure signal to reduce vibrations of the gantry caused by fluctuating torque generated in the engine.

[Effect]

In this invention, the pressure in the cylinder chamber of the engine is detected by a pressure sensor, the actuator is drive-controlled based on the detection result, and the actuator applies an allocation force to reduce the vibration of the frame caused by the fluctuating torque of the engine. to reduce the vibrations of the pedestal.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a Stirling engine is installed on a pedestal 15, and the pedestal 15 is elastically supported by an elastic mount 16.

As will be described in detail later, 17 is an actuator 19 that is composed of an additional weight and a drive source for driving the additional weight, and is mounted on the pedestal 15 in a vertical direction parallel to the crankshaft 12 of the Stirling engine. is a pressure sensor 18 attached to measure the pressure inside the cylinder chamber 101.
A pressure gauge 20 amplifies the signal from the pressure gauge 19 (see Figure 2), and incorporates an algorithm for driving the actuator 17 to reduce vibrations caused by fluctuating torque based on the output signal from the pressure gauge 19. A control circuit 21 is a drive circuit that supplies power to drive the actuator 17 in response to a control signal from the control circuit 20, and the control circuit 20 and drive circuit 21 are configured of electronic circuits, for example. A block diagram of the control system from the pressure sensor 18 to the actuator 17 is shown in FIG.

FIG. 4 is a cross-sectional configuration diagram showing details of the actuator 17. Here, in FIG. , 17b is a cylindrical yoke, 17c is a coil, 17d is a coil support that supports the coil 17c, 17e is a support spring disposed at the upper and lower ends of the yoke 17b to hold the yoke 17b, and 17f is a support spring that passes through the yoke 17b. Guide rod, 17g
are bearings provided at the upper and lower ends of the yoke 17b, respectively, and the yoke 17b slides along the guide rod 17f and is linearly driven in the vertical direction. 17h is a casing.

Next, the effects will be explained.

In the apparatus configured as described above, the equation of motion representing the vibration behavior of the Stirling engine body around the crankshaft is as follows.

■θ+Σkmla” θ−T e −U It a ・
-= (1) l Moment of inertia of the Nistarring engine around the crankshaft km: Spring constant of the elastic mount θ Angular displacement of the Nistarring engine body around the crankshaft 1a: Distance from the crankshaft to the actuator Te Nistarring engine occurs Fluctuation torque U: The characteristics of the damping force fluctuation torque Te generated by the actuator are determined by the magnitude of the pressure in the cylinder chamber 101 and the frequency of the pressure fluctuation, which becomes a disturbance that causes vibration of the pedestal 15 that fixes the Stirling engine. Therefore, in this embodiment, the pressure sensor 18 detects the magnitude of the pressure inside the cylinder chamber and the frequency of the fluctuation, thereby detecting the fluctuating torque generated from the engine and transmitted to the frame 15, which causes vibration, and responding accordingly. The actuator 17 is driven and controlled to reduce the vibration.

That is, pressure fluctuations within the cylinder chamber 101 are detected by the pressure sensor 18, and this signal is amplified by the pressure gauge 19 into an electrical signal having a predetermined voltage, which is input to the control circuit 20. The gain and phase characteristics of this control circuit 20 are set so as to satisfy a predetermined control law, that is, a predetermined control law such that the damping force generated from the actuator 17 cancels out or reduces the fluctuating torque from the Stirling engine. is set to meet. Therefore, the pressure sensor 1
The gain and phase of the signal from 8 are adjusted by the control circuit 20, and the signal drives the actuator 17 via the drive circuit 21. In this way, by operating the actuator 17 with the control circuit 20, the actuator 17 generates an allocation force in a direction that offsets the fluctuating torque of the engine, and the vibration angular displacement of the pedestal 15 itself is reduced. .

That is, the damping force U is applied to the frame 15 by the actuator 17.
The allocation force U of this actuator 17 is a force that synchronizes with the pressure fluctuation in the cylinder chamber 101,
Furthermore, as shown in FIG.
j! a) Acts as a moment. Since this moment (damping force U) is set by the control circuit 20 so as to offset the fluctuating torque Te, the disturbance acting on the pedestal 15 is reduced, and the vibration angular displacement of the pedestal 15 is greatly reduced. Furthermore, since the vibration of the pedestal 15 can be reduced, the force transmitted to the ground via the elastic mount 16 is also reduced, and the influence of vibration on other equipment installed in the vicinity is also reduced.

Next, detailed operation of the actuator 17 will be explained.

In the device configured as shown in FIG. 4, the permanent magnet 17a is radially magnetized and fixed to the yoke 17b to form a magnetic circuit, and the coil 17c
It is set so that a predetermined magnetic flux density can be obtained in the gap where the is inserted. Here, when a drive current is supplied to the coil 17c from the drive circuit 21, an electromagnetic force is generated between the coil 17c and the permanent magnet 17a due to electromagnetic action. At this time, based on the principle of action and reaction, the electromagnetic force generated in the coil 17c is transmitted to the casing 17h fixed to the frame 15 via the coil support 17d,
This electromagnetic force acts on the pedestal 15 and becomes a damping force. on the other hand,
The electromagnetic force acting on the permanent magnet 17a side is caused by the support spring 17e.
The spring force is balanced by the sum of the inertial forces of the yoke 17b and the permanent magnet 17a.

The above mechanical model is shown in FIG. In the figure, 22
is the sum of the masses of the yoke 17b and the permanent magnet 17a (m d
), the spring constant of the support spring 17e is denoted by Kd, and U is the electromagnetic force acting between the coil 17b and the permanent magnet 17a. The support spring 17e also plays a role in ensuring the neutral position of the yoke 17b.

As described above, in this embodiment, the fluctuating torque generated from the engine is detected by the pressure sensor 18 in the cylinder chamber, and the detection result is inputted to the control circuit 20 via the pressure gauge 19.
This control circuit 20 converts it into a control signal according to a predetermined control law to control the drive circuit 21 and actuate the actuator 17.
to drive. The allocation force generated by the actuator 17 acts on the pedestal 15 so as to offset the fluctuating torque, so the vibration angular displacement of the pedestal 15 itself is reduced, and a Stirling engine with extremely low vibration can be realized. - In the above embodiment, a pressure sensor 18 was provided in the cylinder chamber for pressure detection, but since the pressure acting on the power piston 2 is the pressure difference between the buffer chamber 102 and the cylinder chamber 101, as shown in FIG. As shown in FIG. 7, pressure sensors 1B and 23 are installed in both the cylinder chamber 101 and the buffer chamber 102, and as shown in FIG. However, the differential pressure acting on the power piston 2 may be calculated by subtracting these.

〔Effect of the invention〕

As described above, according to the present invention, the actuator, which is composed of an additional weight and a drive source for driving the additional weight and generates a damping force, is fixed to the frame on which the Stirling engine is installed, and the actuator is The sensor detects the pressure fluctuation of the Stirling engine, and based on the detection result, the actuator is driven and controlled so as to reduce the vibration of the pedestal caused by the fluctuating torque generated from the Stirling engine, resulting in extremely low vibration. Not only can a Stirling engine be realized, but even if the pressure changes due to load fluctuations and the fluctuating torque changes, this can be followed, so a sufficient allocation effect can always be expected.

[Brief explanation of drawings]

Fig. 1 is a side configuration diagram showing a vibration reduction device for a Stirling engine according to an embodiment of the present invention, Fig. 2 is a sectional view showing the mounting position of a pressure sensor of the device, and Fig. 3 is a control of the device. A block diagram, FIG. 4 is a sectional view of the actuator shown in FIG. 1, FIG. 5 is a mechanical model diagram of the actuator shown in FIG. 4, and FIG. 6 is a mounting of a pressure sensor according to another embodiment of the present invention. 7 is a control block diagram of the embodiment shown in FIG. 6, and FIG. 8 is a sectional view of main parts of a conventional Stirling engine. 1...Cylinder, 2...Power piston, 12...
Crankshaft, 15... Frame, 16... Elastic mount, 17... Actuator, 18.23... Pressure sensor, 19... Pressure gauge, 20... Control circuit, 21...
... Drive circuit, 22... Additional weight, 24... Subtractor, 17a... Permanent magnet, 17b... Cylindrical yoke,
17c...Coil, 17d...Coil support, 1
7e... Support spring, 17f... Guide rod, 17g.
...Bearing, 17h...Casing. Note that the same reference numerals in the figures indicate the same or equivalent parts. Foil 1 Figure 12: ri/'), :) In 15: Da〃 16 ノ豐-τ? Kun/17: Actor 11-Evening Figure 2 Figure 3 Figure 6 Figure 10 to Figure 7

Claims (2)

[Claims] (1) In a Stirling engine in which pressure fluctuations are generated by the reciprocating motion of a displacer and the pressure fluctuations are applied to a power piston to obtain power, the Stirling engine body is fixedly provided on a pedestal on which the main body of the Stirling engine is installed, an actuator that generates a damping force in response to an external drive control signal; a detector that detects pressure fluctuations in the engine; and a damping force that is generated by the actuator based on the detection signal from the detector. and control means for outputting a drive control signal to the actuator to cancel vibrations of the gantry caused by pressure fluctuations in the engine. (2) The vibration reduction device for a Stirling engine according to claim 1, wherein the actuator comprises an additional weight and a drive source for driving the additional weight.