JPS61164448A - Energy transmitting mechanism for stirling engine - Google Patents

Abstract

PURPOSE:To transmit energy efficiently, by covering the salient section of a crank-shaft with a closed cover of non-magnetic thin substance, by providing a permanent magnet for a rotor inside the comer and an electromagnetic coil for a rotor outside the cover. CONSTITUTION:An inner rotor 12 is fixed on the salient section 1' of a crank- shaft 1, and on the circumferential face of the rotor, a plurality of a pair of permanent magnets 14 are fixed so that the polaritites may be alternately arranged. The inner rotor 12 is covered with a closed cover 6 having a non- magnetic thin section 7. An outer rotor 18 having a plurality of electromagnetic coils 20 is formed outside the closed cover 6. Distances G1, G2 between the thin section 7 and the permanent magnet 14 and between coils 20 are made shorter, and the magnets 14 are magnetically combined with the coils 20. On starting, the outer rotor 18 is clamped with a clamp 25, and alternating current is made to flow to the coils 20, and the inner rotor 12 is rotated. The clamp 25 is taken out, and DC voltage is applied to the coils 20. Then, on starting of engines as not shown in the figure, the outer rotor 18 is fixed by the clamp 25, and an induced electromotive force is obtained from the outer rotor 18. In this manner, energy is efficiently transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an energy transmission mechanism for a Stirling engine that transmits mechanical power or electric power between a Stirling engine main body and external equipment.

[Technical background of the invention and its problems]

A Stirling engine needs to obtain starting torque at the time of starting, and the starting torque is connected to a load such as a generator or a compressor. For this reason, in the past, the crankshaft was led outside from the inside of the sealed crank chamber, and the transmission mechanism was connected to the portion led outside.

In this case, it is necessary to prevent the high-pressure fluid inside the crank chamber from flowing out along the crankshaft. Conventionally, therefore, fluid sealing has been performed using mechanical seals.

However, in a mechanical seal, a rotating ring fixed to the crankshaft and a fixed ring fixed to a fixed part such as the crank wall are in sliding contact, and this sliding part performs a sealing function. Therefore, the higher the sealing performance is, the more the power loss on the friction surface cannot be ignored, and the external loss also becomes larger. For this reason, when the fluid inside the crank chamber is at high pressure, mechanical loss can no longer be ignored.

In addition, the one-herc transmission mechanism between the crankshaft and external equipment itself leads to an increase in the size of the system.In addition, when using a mechanical seal like the one described above, there is a need for lubrication and cooling of the sliding parts. More systems will be needed for this purpose. Therefore, there was a problem in that it was impossible to avoid increasing the size of the system.

(Object of the invention) The present invention was made based on the above problem,
The purpose is to provide an energy transmission mechanism for a Stirling engine that exhibits good sealing performance, has little power loss, and can be downsized.

[Summary of the Invention] The present invention is characterized in that a crankshaft connected to a Stirling engine body is sealed inside, and a thin-walled cylindrical part of a non-magnetic material coaxial with the shaft is formed in a portion surrounding the crankshaft. a sealing cover; and an inner rotor, which is fixed to the crankshaft and has a plurality of radially oriented permanent magnets disposed on the outer circumferential portion thereof and facing and covering the inner surface of the thin-walled cylindrical portion through a minute gap. , a plurality of coils are rotatably installed on the outer surface of the sealing cover coaxially with the crankshaft, and are wound around a radial line at a position facing the permanent magnet through the thin-walled cylindrical portion. It is characterized by comprising an outer rotor arranged in the form of an outer rotor and a means for selectively fixing the outer rotor.

That is, in the present invention, by completely sealing the crankshaft inside the sealing cover, the high-pressure fluid inside the crank chamber is prevented from flowing out to the outside. An inner rotor fixed to the crankshaft and an outer rotor facing the inner rotor via the sealing cover are provided.

The inner rotor is provided with a permanent magnet, and the outer rotor is provided with an electromagnet at a position facing the permanent magnet. Further, the outer rotor has a structure that can be selectively fixed.

When the outer rotor is fixed and an alternating current voltage is applied to the electromagnet,
The inner rotor rotates in synchronization with this alternating voltage. Therefore, in this case, a synchronous motor is configured. When the outer rotor is allowed to rotate and a DC voltage is applied to the electromagnet,
It functions as an electromagnetic coupling, and rotational torque is transmitted between the inner rotor and the outer rotor. Furthermore, if the outer rotor is fixed and the inner rotor is rotated, alternating current power can be extracted from the electromagnets of the outer rotor. In this case, it functions as a generator. Such mechanical torque and power transmission is collectively referred to as energy transmission herein.

〔Effect of the invention〕

According to the present invention, since the crankshaft can be sealed inside the sealing cover, leakage of high-pressure fluid inside the crank chamber can be completely prevented. Therefore, maintenance and inspection work such as replenishment of internal gas can be greatly reduced.

In addition, since the rotational torque is electromagnetically transmitted (there is no mechanical power loss and the generation of heat can be greatly reduced), the cooling and lubrication system is not required as in the past. Not only can this be omitted, it also eliminates the need for a clutch for torque transmission, allowing for significant downsizing.Also, by setting the electromagnetic force to an appropriate value, the torque limiter can be used in the event of an overload. As a result, a highly safe device can be provided.

Furthermore, since the transmission mechanism can be directly used as a generator, there is no need to provide a separate generator as an external device, and the system can be simplified accordingly.

(Embodiment of the Invention) Hereinafter, an energy transmission mechanism of a Stirling engine according to an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a crankshaft whose base end is connected to a Stirling engine body (not shown) and whose distal end extends from an opening 3 of the crank chamber 2 to the outside of the crank chamber 2. As shown in FIG. This crankshaft 1 is rotatably supported by a bearing 5 fixed to an opening 3 of a rear rank space 2 via a support ring 4. The crankshaft 1 is coaxially housed inside a bottomed cylindrical sealing cover 6 that seals the opening 3 of the crank chamber 2 . The entire sealing cover 6 is made of a non-magnetic material such as stainless steel, has a thin wall portion 7 on its circumferential surface, and rotatably supports the tip of the crankshaft 1 inside its bottom 18. The bearing 9 is fixed. In order to prevent the high-pressure fluid filled inside the crank chamber 2 from flowing out, the opening 3 of the crank chamber 2 and the opening flange 10 of the sealing cover 6 are sealed with a seal ring 11. ing.

Further, inside the sealed container 6, an inner rotor casing is fixed to the outer circumferential portion of the crankshaft 1 and housed therein. As shown in FIG. 2, this inner rotor has an outer circumferential surface that faces the inner surface of the thin-walled portion 7 of the sealing cover 6 with a minute gap G1 in between.
It is composed of six permanent magnets 14 equally distributed in the circumferential direction on the outer periphery of the magnet.

These permanent magnets 14 are each magnetized in the radial direction, and the polarities of the permanent magnets 14 adjacent to each other in the circumferential direction are made to differ from each other.

Bearings 16 and 17 are mounted on the outer circumferential surface of the sealing cover 6 near the opening flange 10 and on the convex portion 15 protruding from the outer surface of the bottom wall 8, respectively.

These bearings 16 and 17 are provided with the sealing cover 6.
A cylindrical outer rotor that completely covers the rotor is rotatably supported. The outer rotor shaft faces the outer circumferential surface of the thin-walled portion 7 of the sealing cover 6 via a minute gap G2, and corresponds to the cylindrical rotor body 19 and the inner circumference of this rotor body 19 and to the permanent magnets 14. It is composed of six coils 20 mounted at different positions. The coil 20 is wound around a radial line so as to generate a radial magnetic flux when the coil 20 is energized.

A hollow rotating shaft 21 is integrally formed at the tip side end of this outer rotor set. The hollow rotating shaft is provided with a slip ring 22 that electrically connects the coil 20 to an electric circuit (not shown). On the other hand, a notch 23 is provided at a specific position in the circumferential direction of the outer peripheral edge at the tip of the outer rotor. A stopper 25 slidably provided on the fixed portion 24 can be selectively fitted into the cutout portion 23 .

Next, the operation of the transmission mechanism according to this embodiment configured as described above will be explained.

That is, in the Stirling engine, it is necessary to obtain starting torque at the time of starting. In this case, first, the stopper 25 is fitted into the notch 23 to fix the outer rotor 18. Next, an AC voltage is applied to the coil 20 via the slip ring 22 from an external electric circuit. This causes the coil 20 to generate a radial alternating magnetic field. This alternating magnetic field produces a magnetic force on the permanent magnets of the inner rotor 12, causing the inner rotor to rotate in synchronization with the alternating voltage. In this way, torque is transmitted to the crankshaft 1 from the outside.

Next, when the Stirling engine starts to start and transmits its torque to an external device, the stopper 25 is released from the notch 23, the outer rotor 18 is made rotatable, and the electric circuit (not shown) is disconnected. DC voltage is supplied to the coil 20 via the slip ring 22. At this time, the coil 20 is energized so that the polarities of magnetic fields adjacent to each other in the circumferential direction are opposite.

This creates a fixed magnetic attraction between the coil 20 and the permanent magnet 14, so that when the inner rotor housing rotates, the outer rotor housing also rotates. That is, in this case! ! Functions as a magnetic coupling.

Furthermore, when extracting electric power from the rotational torque of the Stirling engine to the outside, the stopper 25 is fitted into the notch 23 to fix the external rotor (2).

When the inner rotor rotates, the magnetic flux from the permanent magnet fixed to the inner rotor crosses the coil 20 fixed to the outer rotor, thereby generating an induced electromotive force in the coil 20. If this electromotive force is taken out to the outside via the slip ring 22, it functions as a generator.

In this case, since the inside of the crank chamber 2 is completely sealed by the sealing cover 6, the high-pressure fluid inside will not leak to the outside, and the sliding for sealing will not occur. Since there are no parts, there is little mechanical power loss. Also, with this kind of structure, the crankshaft 1
The various effects described above can be achieved, such as the ability to extract rotational torque from the engine without requiring a mechanical transmission mechanism such as a clutch, and the ability to also use it as a generator.

' Also, in this case, the inertia of the crankshaft 1 can be increased by the presence of the inner rotor 12, so the inner rotor 12 can also have a flywheel function, making it possible to obtain stable output. Become.

Note that the present invention is not limited to the embodiments described above.

For example, only the thin wall portion 7 of the sealing cover may be formed of a non-magnetic material. Moreover, other non-magnetic materials such as plastic can also be used as the material.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a longitudinal cross-sectional view of an energy transmission mechanism for a Stirling engine according to an embodiment of the present invention, and FIG.
A cross-sectional view cut along the line A-A in the figure and viewed in the direction of the arrow. DESCRIPTION OF SYMBOLS 1... Crankshaft, 2... Crank chamber, 6... Sealing cover, 7... Thin wall part, 11... Seal ring,
12...Inner rotor, 14...Permanent magnet, 18...
- Outer rotor, 20... Coil, 21... Hollow rotating shaft, 22... Slip ring, 25... Stopper, G1. G2...Minute gap.

Claims (1)

[Claims] A sealing cover that internally seals a crankshaft connected to the Stirling engine body and is formed with a thin cylindrical part of a non-magnetic material that is coaxial with the shaft in a portion that surrounds the crankshaft, and is fixed to the crankshaft. At the same time,
an inner rotor having a plurality of radially magnetized permanent magnets arranged on the outer circumference facing the inner surface of the thin-walled cylindrical portion through a small gap; and an inner rotor that rotates coaxially with the crankshaft on the outer surface of the sealing cover. an outer rotor including a plurality of coils that are freely provided and are wound around a radial line at positions facing the permanent magnets via the thin-walled cylindrical portion;
An energy transmission mechanism for a Stirling engine, comprising means for selectively fixing the outer rotor.