JP3797294B2 - Stirling engine and actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a Stirling engine and actuator, and more particularly, to a displacer-type Stirling engine and actuator capable of preventing leakage of working gas.
[0002]
[Prior art]
A displacer-type Stirling engine generally includes a case, a displacer slidably disposed in the case, an expansion chamber and a working chamber into which working gas flowing in accordance with the operation of the displacer flows in and out, and the operation A power piston that is operated in response to a change in pressure of the working gas in the room, and an operating rod that is connected to the displacer and operates the displacer at a predetermined timing. Such a displacer-type Stirling engine operates a power piston in response to a pressure change in the working chamber accompanying expansion and contraction due to heating and cooling of the working gas. Therefore, as the working gas used in the Stirling engine, a gas having a small specific heat such as hydrogen or helium is used in order to improve the thermal efficiency.
[0003]
Gases with small specific heat, such as hydrogen and helium, used as the working gas for Stirling engines are likely to leak from the sliding part due to the small size of the molecule, and in general, the seal attached to the sliding part should prevent leakage of the working gas. Is difficult. In particular, since the operating rod connected to the displacer is disposed through the case, it is important to prevent leakage of the operating gas from the through sliding portion. In order to solve such a problem, a method is considered in which the displacer is formed of a sealed container, the displacer is a free piston, and the displacer is operated using a gas spring or gravity.
[0004]
[Problems to be solved by the invention]
Thus, it is difficult for a free piston displacer using a gas spring to set the spring constant of the gas spring and the operating period is substantially determined by the spring constant of the gas spring, making it difficult to make the operating period variable. In addition, a starting mechanism is separately required. Moreover, the free piston type displacer using gravity is limited in the direction of the case in the vertical direction and cannot be disposed sideways.
[0005]
The present invention has been made in view of the above-mentioned facts, and its main technical problem is that the operating cycle of the displacer can be changed as appropriate, the orientation of the case is not limited, and Stirling has a built-in starting function. It is to provide an engine and an actuator. Furthermore, an object of the present invention is to prevent leakage of the working gas from the periphery of the reciprocating power piston and to completely seal the working gas .
[0006]
[Means for Solving the Problems]
In order to solve the above technical problem , according to the present invention, a case, a displacer slidably disposed in the case, and a working gas flowing in accordance with the operation of the displacer flow in and out. In a Stirling engine comprising an expansion chamber and a working chamber, and a power piston that is actuated in response to a change in pressure of the working gas in the working chamber,
A sliding cylinder filled with a working fluid is slidably disposed in the case, and the displacer is slidably disposed in the sliding cylinder, and the expansion chamber and the working chamber Are provided at both ends of the sliding cylinder, and a bellows that expands and contracts according to the pressure of the working fluid is attached to the sliding cylinder, and the power piston is attached to the sliding cylinder or the bellows. Is installed , and
A displacer operating mechanism comprising: a movable yoke disposed in the displacer; and a pair of electromagnetic solenoids disposed in the case and surrounding the movable yoke and provided side by side in an axial direction;
Power piston position detecting means for detecting the operating position of the power piston;
Control means for switching and controlling excitation of the pair of electromagnetic solenoids of the displacer operating mechanism based on a detection signal from the power piston position detecting means,
A Stirling engine is provided.
[0007]
Further, according to the present invention, a case, a displacer slidably disposed in the case, an expansion chamber and a working chamber into and out of which working gas that flows in accordance with the operation of the displacer, and the operation A power piston that is actuated in response to a change in pressure of the working gas in the room, and an actuator that connects the power piston to the actuated member,
A sliding cylinder filled with a working fluid is slidably disposed in the case, and the displacer is slidably disposed in the sliding cylinder, and the expansion chamber and the working chamber Are provided at both ends of the sliding cylinder, and a bellows that expands and contracts according to the pressure of the working fluid is attached to the sliding cylinder, and the power piston is attached to the sliding cylinder or the bellows. Is installed , and
A magnet movable body disposed in the displacer, a cylindrical fixed yoke disposed in the case and surrounding the magnet movable body, and a pair of coils disposed inside the fixed yoke; A displacer operating mechanism comprising:
Switching means for switching the direction of the current applied to the pair of coils of the displacer operating mechanism,
An actuator is provided.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the following, a preferred embodiment of a Stirling engine and actuator constructed according to the present invention will be described in more detail with reference to the accompanying drawings.
[0009]
FIG. 1 shows a cross-sectional view of one embodiment of a Stirling engine constructed in accordance with the present invention.
The Stirling engine of the embodiment shown in FIG. 1 includes a cylindrical case 2. The case 2 is made of a nonmagnetic material such as an aluminum alloy, and has a central sliding portion 21, a heating chamber 22 formed on the left side in the drawing of the central sliding portion 21, and a right side in the drawing of the central sliding portion 21. The cooling chamber 23 is formed. The case 2 is provided with a heating fluid inlet 221 and a heating fluid outlet 222 that open to the heating chamber 22, and a cooling fluid inlet 231 and a cooling fluid outlet 232 that open to the cooling chamber 23. A sliding cylinder 3 made of a nonmagnetic material is disposed on the inner peripheral surface of the central sliding portion 21 of the case 2 so as to be slidable in the axial direction. A displacer 4 is disposed so as to be slidable in the axial direction through the inside of the sliding cylinder 3. The displacer 4 is formed of a non-magnetic material in a cylindrical shape, and a regenerator 5 configured by alternately superimposing heat insulating rings and wire mesh formed in an annular shape by a heat insulating material is disposed therein. ing.
[0010]
An expansion bellows 7 is disposed in the heating chamber 22. One end portion of the expansion bellows 7 is attached to the left end portion in the drawing of the sliding cylinder 3, and the other end portion is attached to the left end wall 24 of the case 2. Accordingly, an expansion chamber 71 is formed in the heating chamber 22, which is defined by the expansion bellows 7, the sliding cylinder 3, and the left end wall 24 and communicates with the regenerator 5 disposed in the cylindrical displacer 4. . On the other hand, a shrink bellows 8 is disposed in the cooling chamber 23. One end of the contraction bellows 8 is attached to the right end in the drawing of the sliding cylinder 3, and the power piston 9 is attached to the other end. Accordingly, a working chamber 81 is formed in the cooling chamber 23, which is defined by the contracted bellows 8 and the sliding cylinder 3 and communicates with the regenerator 5 disposed in the cylindrical displacer 4. The expansion chamber 71, the working chamber 81, and the cylindrical displacer 4 are filled with a working gas having a small specific heat, such as hydrogen or helium. A power take-out shaft 91 is attached to the power piston 9, and the power take-out shaft 91 is disposed through the right end wall 25 of the case 2.
[0011]
The Stirling engine of the embodiment shown in FIG. 1 includes a displacer operating mechanism 10 that periodically operates the displacer 4. The displacer operating mechanism 10 includes a magnet movable body 11 disposed on the outer peripheral surface of the center portion of the displacer 4, and a cylindrical fixed yoke 12 disposed inside the case 2 so as to surround the magnet movable body 11. And a pair of coils 13 and 14 provided in the axial direction inside the fixed yoke 12. The magnet movable body 11 includes an annular permanent magnet 111 that is mounted on the outer peripheral surface of the displacer 4 and has magnetic poles on both axial end surfaces, and a pair of movable yokes 112 and 113 that are disposed on the axially outer side of the permanent magnet 111. And is composed of. The permanent magnet 111 in the illustrated embodiment has the right end face magnetized to the N pole in FIG. 1, and the left end face in FIG. 1 is magnetized to the S pole. The pair of movable yokes 112 and 113 are formed in an annular shape from a magnetic material. The magnet movable body 11 configured in this way is disposed in an annular fitting groove 41 formed on the outer peripheral surface of the displacer 4.
[0012]
The fixed yoke 12 is formed in a cylindrical shape from a magnetic material, and is disposed in an annular fitting groove 26 formed on the inner peripheral surface of the case 2. A pair of coils 13 and 14 are disposed inside the fixed yoke 12. The pair of coils 13 and 14 are wound around a bobbin 15 formed of a nonmagnetic material such as a synthetic resin along the inner periphery of the fixed yoke 12 in a reverse winding manner. The pair of coils 13 and 14 are controlled to switch the direction of the applied current by a control means described later.
[0013]
As described above, the displacer operating mechanism 10 constituted by the magnet movable body 11, the fixed yoke 12, and the pair of coils 13 and 14 operates according to the principle of a linear motor. The operation will be described below with reference to FIG.
In the displacer operating mechanism 10 in the illustrated embodiment, as shown in FIGS. 2A and 2B, the N pole of the permanent magnet 111, one movable yoke 112, one coil 13, and the fixed yoke 12 are provided. A magnetic circuit passing through the other coil 14 (MC2), the other movable side yoke 113, and the south pole of the permanent magnet 111 is formed. In such a state, when currents in opposite directions are passed through the pair of coils 13 and 41 in the direction shown in FIG. 2A, the magnet movable body 11, that is, the displacer 4 is shown in FIG. As shown by the arrow in (a), thrust is generated to the right. On the other hand, when a current is passed through the pair of coils 13 and 14 in the direction opposite to that shown in FIG. 2A as shown in FIG. 2B, the magnet movable body 11, that is, the displacer 4 is shown in accordance with Fleming's left-hand rule. As shown by the arrow in 2 (b), a thrust is generated to the left.
[0014]
The Stirling engine of the embodiment shown in FIG. 1 includes power piston position detecting means 16 that detects the operating position of the power piston 9. The power piston position detection means 16 is composed of a stroke sensor disposed to face the power take-out shaft 91 connected to the power piston 9 and sends the detection signal to the control means 17 described later. The output value of the stroke sensor as the power piston position detecting means 16 will be described with reference to FIG. In FIG. 3, the horizontal axis indicates the stroke of the power piston 9, that is, the power take-out shaft 91, and the vertical axis indicates the voltage value. As shown in FIG. 3, the stroke sensor outputs a voltage value proportional to the stroke of the power piston 9, that is, the power take-out shaft 91. In FIG. 3, L1 is the return side full stroke position (bottom dead center), and L10 is the feed side full stroke position (top dead center). The control means 17 is constituted by a microcomputer, and a central processing unit (CPU) that performs arithmetic processing according to a control program, a read-only memory (ROM) that stores control programs and the like, and a random read / write that stores arithmetic results and the like. An access memory (RAM) is provided. The control means 17 outputs a control signal to the pair of coils 13 and 14 constituting the displacer operating mechanism 10 based on the operating position signal of the power piston 9 detected by the power piston position detecting means 16.
[0015]
The Stirling engine of the embodiment shown in FIG. 1 is configured as described above, and the operation thereof will be described below with reference to the flowchart shown in FIG. 4 and the explanatory view showing the operating state shown in FIG.
FIG. 5A shows the end of contraction. At this time, the power piston 9 is located at the left end position, that is, the return side full stroke position (bottom dead center), and the displacer 4 is also located at the left end position, ie, the return side full. It is located at the stroke position (bottom dead center). To start the Stirling engine from the state of FIG. 5A, the control means 17 drives the displacer operating mechanism 10 so as to operate the displacer 4 to the right in the drawing (step S1). That is, the control means 17 controls the pair of coils 13 and 14 constituting the displacer operating mechanism 10 so that currents in opposite directions are applied in the directions shown in FIG. As a result, the magnet movable body 11, that is, the displacer 4 moves to the right as shown in FIG. By moving the displacer 4 to the right, the working gas in the working chamber 81 flows into the expansion chamber 71 through the regenerator 5 disposed in the tubular displacer 4. At this time, the working gas that has been cooled in the working chamber 81 is heated by heat exchange when passing through the regenerator 5. The state in which the displacer 4 has moved to the right by a predetermined amount as shown in FIG. 5B is at the start of expansion, and the working gas that has flowed into the expansion chamber 71 from this time is heated by the heating fluid introduced into the heating chamber 22. It expands when heated. As a result, in the displacer 4, as shown in FIG. 5 (c), the expansion bellows 7 expands, the sliding cylinder 3 and the contraction bellows 8 move to the right in the drawing, and the displacer 4 moves to the right. . At the end of expansion shown in FIG. 5C, the power piston 9 is moved to the right end position, that is, the feed side full stroke position (top dead center) in the drawing, and the displacer 4 is also moved to the right end position, that is, the feed side full stroke position ( Moved to the top dead center).
[0016]
As described above, if the displacer operating mechanism 10 is driven so that the displacer 4 is operated to the right in the figure in step S1, the control means 17 proceeds to step S2 and detects the detection signal from the power piston position detecting means 16. Based on this, whether or not the stroke position L of the power piston 9, that is, the power take-out shaft 91 is larger than the stroke position L9 that is a threshold value a predetermined amount before the full stroke position (top dead center) L10 (L> L9). Check. If the stroke position L is not greater than L9, the control means 17 proceeds to step S3, where the stroke position L of the power piston 9, that is, the power take-out shaft 91, is a predetermined amount before the return side full stroke position (bottom dead center) L1. It is checked whether or not the stroke position L2 is smaller than the value (L <L2). Since the power piston 9 is moved to the feed side this time, the stroke position L is not smaller than L2, and the control means 17 returns to step S2.
[0017]
If the stroke position L is greater than L9 in step S2, the control means 17 determines that the power piston 9 has exceeded a position a predetermined amount before the end of expansion shown in FIG. 5C, and step S4. Then, the displacer operating mechanism 10 is driven so as to operate the displacer 4 to the left in the drawing. That is, the control means 17 controls the pair of coils 13 and 14 constituting the displacer operating mechanism 10 to apply currents in opposite directions in the direction shown in FIG. As a result, the magnet movable body 11, that is, the displacer 4 moves to the left as shown in FIG. As the displacer 4 moves to the left, the working gas in the expansion chamber 71 flows into the working chamber 81 through the regenerator 5 disposed in the cylindrical displacer 4. At this time, the working gas heated in the expansion chamber 71 is cooled by heat exchange when passing through the regenerator 5. The state shown in FIG. 5D is when the contraction starts, and the displacer 4 reaches the left end position, that is, the return side full stroke position (bottom dead center). When the state shown in FIG. 5D is at the start of contraction, the power piston 9 is located at the right end position in the drawing, that is, at the feed side full stroke position (top dead center). Then, the working gas in the working chamber 81 is cooled and contracted by the cold air introduced into the cooling chamber 23 from the state shown in FIG. As a result, the contraction bellows 8 forming the working chamber 81 contracts and the power piston 9 is moved to the left end position in the drawing, that is, the return side full stroke position (bottom dead center) at the end of contraction shown in FIG. .
[0018]
On the other hand, if the displacer operating mechanism 10 is driven so as to operate the displacer 4 to the left in the drawing in step S4 as described above, the control means returns to step S2 and the power piston 9, that is, the power take-out shaft 91 is controlled. It is checked whether or not the stroke position L is larger than the stroke position L9 which is a threshold value a predetermined amount before the sending side full stroke position (top dead center) L10. Since the power piston 9 is moved to the return side this time, the stroke position L is not greater than L9. Therefore, the control means 17 proceeds to step S3 and the stroke position L of the power piston 9, that is, the power take-out shaft 91 is returned. It is checked whether or not the stroke position is smaller than the stroke position L2 which is a threshold value a predetermined amount before the side full stroke position (bottom dead center) L1. If the stroke position L is not smaller than L2, the control means 17 determines that the power piston 9 has not yet reached L2, returns to step S2, and repeatedly executes steps S2 and S3. If the stroke position L of the power piston 9 is smaller than L2 in step S3, the control means 17 determines that the power piston 9 has exceeded L2, and proceeds to step S5 to operate the displacer 4 to the right in the drawing. Control is performed so that currents in opposite directions are applied to the pair of coils 13 and 14 in the direction shown in FIG. 2A so as to drive the operating mechanism 10.
[0019]
By repeating the above cycle, the power piston 9, that is, the power take-out shaft 91 can be reciprocated. Therefore, the crankshaft can be rotated by connecting the power take-off shaft 91 to the crankshaft via an appropriate connecting rod.
[0020]
In the above-described embodiment, the displacer 4 is stopped at the feed-side full stroke position (top dead center) and the return-side full stroke position (bottom dead center), and the power piston 9, that is, the power take-out shaft 91 is moved to the feed-side full stroke position. By controlling to stop at (top dead center) L10 and the return side full stroke position (bottom dead center) L1, the actuated member can be used as an actuator that operates at two positions. Thus, when used as an actuator, a switching signal may be input to the control means 17. In this case, the means for inputting the switching signal to the control means 17 functions as a switching means for switching the direction of the current applied to the pair of coils 13 and 14.
[0021]
In the Stirling engine and actuator according to the above-described embodiment, the displacer operating mechanism 10 that operates the displacer 4 surrounds the magnet movable body 11 disposed in the displacer 4, and surrounds the magnet movable body 11 and is disposed inside the case 2. A cylindrical fixed yoke 12 provided and a pair of coils 13 and 14 provided in the axial direction inside the fixed yoke 12 so that a rod or the like for driving the displacer 4 does not penetrate the case 2. A sealed container can be formed and leakage of the working gas can be prevented. Further, the operating cycle of the displacer 4 can be easily changed by appropriately controlling the timing of applying power to the pair of coils 13 and 14, and there is no restriction on the direction in which the case 2 is arranged.
[0022]
Next, another embodiment of a Stirling engine configured according to the present invention will be described with reference to FIG. In the embodiment of FIG. 6, the same members as those of the Stirling engine shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The Stirling engine shown in FIG. 6 is formed by extending the sliding cylinder 3 instead of the contracting bellows 8 disposed in the cooling chamber 23 in the embodiment shown in FIG. In the figure, a power piston 9 is mounted on the right end. And the cooling fin 31 is mounted | worn with the outer periphery of the right end part in the figure of the sliding cylinder 3. As shown in FIG.
[0024]
【The invention's effect】
Since the Stirling engine and the actuator according to the present invention are configured as described above, the following effects can be obtained.
That is, the displacer operating mechanism for operating the displacer is composed of a movable yoke disposed in the displacer and a pair of electromagnetic solenoids disposed in the case so as to surround the movable yoke and are provided in the axial direction. Since the rod or the like for driving the gas does not penetrate the case, the leakage of the working gas can be prevented. In particular, in the present invention, the displacer is disposed in a sliding cylinder filled with a working fluid, and the sliding cylinder is provided with a bellows that expands and contracts according to the pressure of the working fluid. Attached to the sliding cylinder or bellows. For this reason, it is possible to prevent the working fluid from leaking out of the periphery of the power piston and to achieve complete sealing.
Moreover, since the displacer operating mechanism has a starting function, it is not necessary to provide a starting mechanism separately. Furthermore, the operating cycle of the displacer can be easily changed by appropriately controlling the timing of exciting the pair of electromagnetic solenoids, and there is no restriction on the case arrangement direction. In the present invention, since the displacer is instantaneously switched by the electromagnetic force of the displacer operating mechanism, the thermal efficiency is higher than that of the crankshaft interlocking system.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating one embodiment of a Stirling engine constructed in accordance with the present invention.
FIG. 2 is an operation explanatory diagram of a displacer operating mechanism constituting the Stirling engine configured according to the present invention.
FIG. 3 is an explanatory diagram showing an output signal of a power piston position detecting means constituting a Stirling engine configured according to the present invention.
FIG. 4 is a flowchart showing an operation procedure of control means constituting the Stirling engine configured according to the present invention.
FIG. 5 is an explanatory view showing an operating state of the Stirling engine shown in FIG. 1;
FIG. 6 is a cross-sectional view showing another embodiment of a Stirling engine configured according to the present invention.
[Explanation of symbols]
2: Case 22: Heating chamber 23: Cooling chamber 3: Sliding cylinder 4: Displacer 5: Regenerator 7: Expansion bellows 8: Contraction bellows 9: Power piston 91: Power take-off shaft 10: Displacer operating mechanism 11: Magnet movable Body 111: Permanent magnet 112, 113: A pair of movable yokes 12: Fixed yoke 13, 14: A pair of coils 16: Power piston position detection means 17: Control means

Claims (2)

A case, a displacer slidably disposed in the case, an expansion chamber and a working chamber into which working gas flowing in accordance with the operation of the displacer flows in and out, and changes in pressure of the working gas in the working chamber In a Stirling engine comprising a correspondingly operated power piston,
A sliding cylinder filled with a working fluid is slidably disposed in the case, and the displacer is slidably disposed in the sliding cylinder, and the expansion chamber and the working chamber Are provided at both ends of the sliding cylinder, and a bellows that expands and contracts according to the pressure of the working fluid is attached to the sliding cylinder, and the power piston is attached to the sliding cylinder or the bellows. Is installed , and
A magnet movable body disposed in the displacer, a cylindrical fixed yoke disposed in the case and surrounding the magnet movable body, and a pair of coils disposed inside the fixed yoke; A displacer operating mechanism comprising:
Power piston position detecting means for detecting the operating position of the power piston;
Control means for switching and controlling the direction of the current applied to the pair of coils of the displacer operating mechanism based on a detection signal from the power piston position detecting means;
Stirling engine characterized by that. A case, a displacer slidably disposed in the case, an expansion chamber and a working chamber into which working gas flowing in accordance with the operation of the displacer flows in and out, and changes in pressure of the working gas in the working chamber A power piston actuated correspondingly, and an actuator for connecting the power piston to the actuated member,
A sliding cylinder filled with a working fluid is slidably disposed in the case, and the displacer is slidably disposed in the sliding cylinder, and the expansion chamber and the working chamber Are provided at both ends of the sliding cylinder, and a bellows that expands and contracts according to the pressure of the working fluid is attached to the sliding cylinder, and the power piston is attached to the sliding cylinder or the bellows. Is installed , and
A magnet movable body disposed in the displacer, a cylindrical fixed yoke disposed in the case and surrounding the magnet movable body, and a pair of coils disposed inside the fixed yoke; A displacer operating mechanism comprising:
Switching means for switching the direction of the current applied to the pair of coils of the displacer operating mechanism,
An actuator characterized by that.

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