JPH04228828A - Free piston engine - Google Patents

Abstract

PURPOSE: To obtain an inexpensive free piston engine with a simple structure and short axial direction space by arranging plural counter masses axisymmetrically for a rod and also forming an energizing means by a coil spring. CONSTITUTION: A cylinder 16 storing a piston 15 for an engine is formed in the cylinder case 13 of an engine case 11. A compressor mechanism 17 is formed as an output mechanism in the opposite side to the combustion chamber 29 side of a central case 12 and a piston 19 for a compressor is connected with the piston 15 for an engine by a rod 21. Further, counter masses 24a, 24b are fitted onto respective shafts 22a, 22b and rack teeth 25a, 25b, 26a, 26b are provided on these faced surfaces respectively and also pinion gears 27a, 27b are provided therebetween. Coil springs 28a, 28b are provided between the counter masses 24a, 24b and the central case 12 and the counter masses 24a, 24b are energized to the compressor mechanism side.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a free piston engine, and more particularly to a vibration prevention mechanism for the engine, and is used as a power source for compressors, hydraulic pumps, generators, and the like.

0002

[Prior Art] As a prior art related to the present invention, Japanese Patent Application Laid-Open No. 62
There is one disclosed in Japanese Patent No. -153578. This consists of an engine case with a cylinder, a piston housed in the cylinder, a rod placed coaxially with the piston and connected to the piston at one end, a compressor as an output mechanism configured at the other end of the rod, and a rod in the center of the rod. A free piston engine is a free piston engine consisting of a counter mass connected to the rod via a pinion gear and movable relative to the rod, and an air spring mechanism that urges the counter mass away from the piston. By applying a reversing force to the piston of the compressor, energy efficiency is improved.

0003

However, this prior art has the following two problems. In other words, since two pinion gears are arranged between one counter mass and the rod, there may be problems with the symmetry of the plurality of rack teeth provided on the rod and counter mass with respect to the axis, and the mounting of the pinion gear. Manufacturing errors such as misalignment of each component cannot be absorbed, which may result in poor assembly or poor engagement of each component, as well as abnormal noises during operation due to errors.

[0004] Therefore, the present invention aims to eliminate such problems and eliminate problems in assembly and work by absorbing the errors even if they occur in the manufacturing of each component. is the first technical issue.

[0005] The second problem with the prior art is as follows. That is, since an air spring piston is used as the biasing means for the counter mass, the sealing structure is complicated.
Requires many parts. In addition, since the air spring piston mentioned above is placed on the rod between the rack teeth of the rod and the piston, the reciprocating space of the air spring must be considered in addition to the reciprocating space of the rack teeth on the piston and rod. However, the axial space of the engine case is large.

A second technical object of the present invention is to provide a free piston engine that is inexpensive, has a simple structure, and has a short axial space.

[0007]

[Means for solving the problem] The technical means taken to solve the above problem are to arrange a plurality of counter masses axially symmetrically with respect to the rod, and to use a coil spring as the biasing means. .

[0008]

[Operation] The first technical means described above operates as follows. Since a plurality of counter masses are arranged axially symmetrically with respect to the rod, one pinion gear can be combined with one counter mass and these can be arranged axially symmetrically. As a result, manufacturing errors in the rack teeth provided on the counter mass and rod, as well as misalignment in the mounting position of the pinion gear, are absorbed independently when each counter mass and pinion gear are assembled, resulting in poor assembly and misalignment. There are no defects or abnormal noises during operation.

[0009] By taking such a second technical means, the biasing means can be replaced by only a coil spring, and the counter mass is reliably biased without any special configuration or assembly. Furthermore, in terms of space, there is no need to provide a coil spring between the piston and the rack teeth of the rod, and the axial space can be reduced.

0010

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 and 2. The engine case 11 is the center case 1
2, a cylinder case 13, and a cylinder head 14. The cylinder case 13 and the cylinder head 14 form a combustion chamber 29 of a well-known two-stroke engine.

A cylinder 16 is formed in the cylinder case 13 to accommodate an engine piston 15 in an airtight and slidable manner.
When the piston 15 slides, the combustion chamber 2
A pump chamber 31 having a volume change opposite to that of pump chamber 9 is formed.

Further, on the opposite side of the central case 12 from the combustion chamber 29 side, there is a well-known compressor mechanism 17 as an output mechanism.
is formed. The compressor mechanism 17 includes a compressor cylinder 18, a compressor piston 19, and a valve member 20. The compressor piston 19 and the engine piston 15 are coaxially arranged and connected by a rod 21 so that they move together, so that the engine and the compressor mechanism 17 perform opposite strokes.

Two shafts 22a and 22b are arranged at axially symmetrical positions with respect to the rod 21 and are fixed to the central case 12. As shown in FIGS. 1 and 2, slide bearings 23a and 23b are mounted on each shaft 22a and 22b.
Counter masses 24a and 24b having the same diameter are fitted together and are movable on the shaft. Rack teeth 25a, 25b, 26a, and 26b are provided on the opposing surfaces of the rod 21 and counter masses 24a and 24b, respectively, and pinion gears 27a and 27b are meshed therebetween and rotatably supported by the central case 12. ing. counter mass 24a
, 24b and the side wall of the central case 12 are arranged coil springs 28a and 28b, respectively, to bias the counter masses 24a and 24b toward the side opposite to the engine, that is, toward the compressor mechanism.

In the above configuration, when the spark plug 32 is ignited to ignite and agitate the air-fuel mixture in the combustion chamber 29, the piston 15 slides toward the compressor mechanism 17 (towards the right in FIG. 1), causing combustion. While the exhaust stroke in the chamber 29 is performed, the air-fuel mixture flows into the combustion chamber 29 from the pump chamber 31 via the scavenging passage 13a formed in the cylinder case 13.
A scavenging and suction process is performed. At the same time, the rod 21 and the compressor piston 19, which are integrally connected to the piston 15, also move to the right. This compresses the gas in the compressor chamber and sends it out as output via the boat and valve provided on the valve member 20.

When the rod 21 moves to the right, the pinion gears 27a and 27b that mesh with the rack teeth 25a and 25b provided on the rod 21 rotate, thereby causing the pinion gears 27a and 27b to mesh with the rack teeth 26a, respectively.
, 26b, the counter masses 24a, 2 are in mesh with each other via
4b moves to the left in FIG. At this time, the counter masses 24a, 24b compress the coil springs 28a, 28b, and after the kinetic energy of the counter masses 24a, 24b becomes zero, the counter masses 24a, 24b are compressed as shown in FIG. It begins to move to the right, thereby causing the pinion gears 27a and 27b to rotate in the opposite direction, and moving the rod 21 upward in FIG. 1 to the left.
Compression is applied to the piston 15 and suction force is applied to the compressor piston 19. By repeating the above steps, the power of the engine is extracted to the outside using the compressor mechanism 17 as an output mechanism.

In this embodiment, the counter masses 24a and 24b operate independently on the rod 21 via the pinion gears 27a and 27b, so even if an error occurs between the rack teeth or in the mounting position of the pinion gear, each Absorption is possible at the positions of the counter masses 24a and 24b.

In this embodiment, the biasing means for the counter masses is a coil spring, but an air spring acting on each counter mass may also be used. Further, the output mechanism is not limited to the compressor mechanism, but may also be a hydraulic pump or a generator. Furthermore, although two counter masses are sufficient, it is also possible to use three or more than four counter masses in view of size and space.

[0018]

[Embodiment 2] Please refer to FIGS. 3 and 4. engine case 1
1 includes a central case 12, a cylinder case 13, a cylinder head 14, and pinion gears 27a and 27b, which will be described later.
side wall members 12a, 12b, and an upper plate 12c for accommodating
, a lower plate 12d. Here, the side wall members 12a and 12b that accommodate the above-mentioned pinion gears 27a and 27b portions are
, the upper plate 12c, and the lower plate 12d are collectively called the central case. The cylinder case 13 and cylinder head 14 form a combustion chamber 29 of a known two-stroke engine.
is formed. The cylinder case 13 is formed with a cylinder 16 having openings at both ends thereof and accommodating a piston 15 for the engine.

A cylinder 18 for a compressor, a compressor piston 19, and a valve member 20, which are well-known as an output mechanism, are disposed on the opposite side of the central case 12 from the combustion chamber. The compressor piston 19 and the engine piston 15 are coaxially arranged and connected by a rod 21, so that the movement of one piston is followed by the other piston making the same movement. Two shafts 22a and 22b are disposed parallel to the rod 21 at axially symmetrical positions and fixed to the central case 12.

A counter mass 24a having slide bearings 23a, 23b is mounted on each shaft 22a, 22b.
, 24b are fitted. Counter masses 24a and 24b respectively disposed on shafts 22a and 22b, which are axially symmetrical with respect to rod 21, can slide on each shaft by the slide bearings 23a and 23b. Rack teeth 25a, 25b, 26a are provided on the opposing surfaces of the rod 21 and the counter masses 24a, 24b, respectively.
, 26b are configured. The rack teeth 25a, 26
A pinion gear 27a is connected to both the lock teeth 25a,
26a so that it can roll and move in the axial direction of the rod 21.

Similarly, a pinion gear 27b is connected between the rack teeth 25b and 26b.
The rod 21 is disposed so as to be freely movable while rolling in the axial direction of the rod 21. Coil springs 28a and 28b are respectively disposed between the side wall 12A and the side surface 24c of the counter masses 24a and 24b on the engine combustion chamber side.
4a and 24b are urged toward the combustion chamber side opposite to the engine, that is, toward the compressor mechanism 17 side.

In the above configuration, the piston 15 is moved toward the compressor mechanism 17 side (
3), and along with the movement of the piston 15, the intake and exhaust processes within the combustion chamber 29 are performed. At the same time, the rod 2 is integrally connected to the piston 15.
1 and the compressor piston 19 also slide to the right in FIG. As a result, the gas in the compressor chamber 18 is compressed and sent out as output to the outside via the port 20a provided in the valve member 20 and the valve. This rod 21
pinion gears 27a, which engage with rack teeth 25a, 25b provided on the rod 21, respectively, when the rod 21 slides in the right direction;
27b rotates, thereby causing pinion gears 27a, 27
The counter masses 24a and 24b, which are engaged with the counter masses 24a and 24b through the respective rack teeth 26a and 26b, move to the left in FIG.

At this time, the counter masses 24a, 24b compress the coil springs 28a, 28b, and the counter masses 24a, 24b compress the coil springs 28a, 28b.
After the kinetic energy of a, 24b becomes zero, the counter mass 24a,
24b begins to move to the right in FIG. 3, causing the pinion gears 27a and 27b to rotate in opposite directions, causing the rod 21 to move to the left in FIG. 3 and enter the compression stroke of the engine.

By repeating the above steps, the power of the engine is sent out to the outside using the compressor mechanism 17 as an output mechanism.

[0025] The coil springs 28a, 28b are arranged on an extension of the sliding position of the counter masses 24a, 24b,
Since it is not on the sliding extension of the piston 15, the reciprocating space of the rack teeth 25a, 25b of the rod 21 and the counter mass 2 are
4a, 24b reciprocating space and coil springs 28a, 2
The adhesion length of 8b can be set separately. Therefore, the engine case 11 can be made more compact in the axial direction.

Note that the output mechanism is not limited to the compressor mechanism 17, and a hydraulic pump, a generator, or the like may be used. Furthermore, two counter masses are sufficient, but due to size and space considerations, three counter masses are required to surround the rod 21.
It is also possible to arrange four or more.

[0027]

[Effects of the Invention] According to the present invention, errors in the symmetry of the rack teeth and errors in the mounting position of the pinion gear can be adjusted at the position of the counter mass by dividing the counter mass.
There are no assembly defects or poor meshing that occur in the past, and furthermore, the tolerance range for manufacturing errors of each component can be widened, error management is easy, and manufacturing is possible at low cost.

[0028] Moreover, since the assembly is not impossible, the backlash of each gear can be reduced, so that noise can be reduced. Furthermore, in order to avoid interference between the side wall of the conventional U-shaped counter mass and the support part of the pinion gear, the structure and assembly were complicated, but in the present invention, the support part of the pinion gear and the counter mass do not interfere with each other. The structure and assembly are easy, and the weight can be reduced.

As described above, by using a coil spring as a biasing means for the counter mass, it is possible to provide a free piston engine with a simple structure and low cost. In addition, it is not necessary to provide the coil spring on the sliding extension of the piston, but by providing it on the sliding extension of the counter mass, the axial length of the rod and engine case can be shortened.
A compact free piston engine can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a free piston engine according to the invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is a sectional view of a free piston engine according to another example of the present invention.

FIG. 4 is a sectional view taken along line II-II in FIG. 3;

[Explanation of symbols]

11 Engine case 15 Piston 21 Rods 24a, 24b Counter masses 25a, 25b Rack teeth 36a, 26 of rod 21
b Rack teeth 27a, 27b of counter masses 24a, 24b Pinion gears 28a, 28b Coil spring

Claims (7)

[Claims] 1. An engine case having a cylinder, a piston housed in the cylinder, a rod disposed coaxially with the piston and having one end connected to the piston, an output mechanism configured at the other end of the rod, A counter mass connected to the center of the rod via a pinion gear and movable relative to the rod, and a biasing means for biasing the counter mass in a direction away from the piston, the counter mass comprising: A free piston engine in which a plurality of free piston engines are arranged axially symmetrically with respect to the rod. 2. A free piston engine according to claim 1, wherein said biasing means comprises a coil spring. 3. The counter mass has a slide bearing that fits into a shaft fixed to the engine case, and the coil spring is arranged approximately coaxially with the shaft and between the counter mass and the engine case. 3. The free piston engine according to claim 2, wherein the free piston engine is disposed between. 4. The output mechanism comprises a compressor having a compressor piston connected to the rod, and a second cylinder provided in the engine case and accommodating the compressor piston. The free piston engine according to any one of Item 3. 5. An engine case having a cylinder;
A piston housed in the cylinder, a rod disposed coaxially with the piston and connected at one end to the piston, an output mechanism configured at the other end of the rod, and a pinion in the center of the rod. It comprises a counter mass connected via a gear and moved in a direction opposite to the rod, and a biasing means for biasing the counter mass in a direction away from the piston, the biasing means comprising a coil spring. A free piston engine featuring 6. The free piston engine according to claim 5, wherein the coil spring is disposed between an end surface of the counter mass on the piston side and a side wall of the engine case opposing the end surface. 7. The free piston engine according to claim 5, comprising a compressor having a compressor piston connected to the rod, and a cylinder provided in the engine case and accommodating the compressor piston.