Two-cycle engine

Abstract

To provide a two-cycle engine capable of appropriately scavenging air and sucking air by using a simple structure.SOLUTION: A two-cycle engine includes: a piston 13 disposed in a combustion chamber 3; a compression movable part 15 disposed in an intake chamber 5; a shaft 17 coupling the piston 13 and the compression movable part 15 to each other and fitted and supported by a relay hole 27 to enable reciprocation; an exhaust port 19 for discharging air from the combustion chamber 3; and an intake port 21 that can be opened / closed in accordance with a stroke of the piston 13. When explosion expansion in the combustion chamber 3 causes stroke to a bottom dead center side of the piston 13, the exhaust port 19 and the intake port 21 are opened, and air is sucked from the intake chamber 5 in which the compression movable part 15 is compressed through the intake port 21 into the combustion chamber 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a two-cycle engine for use in automobiles, motorcycles, and the like.

Background Art

[0002] As a conventional two-cycle engine, there is one shown in FIG. 23 described in Patent Document 1. This two-cycle engine 101 includes a cylinder 105 having a piston 103. In this cylinder 105, a combustion chamber 107 and a first intake chamber 109 are partitioned by the piston 103.

[0003] An additional piston 113 is provided above the crank chamber 111 at the lower part of the cylinder 105. The additional piston 113 is connected to the piston 103 by a rod 115, and a chamber 117 partitioned from the chamber 109 by the additional piston 113 is provided.

[0004] Therefore, when the piston 103 moves downward, before the piston 103 reaches the bottom dead center, the piston 103 opens the port 119 on the bottom dead center side. Due to this opening, the exhaust gas in the combustion chamber 107 is discharged from the port 119, and the pressure in the combustion chamber 107 rapidly decreases. At this time, the valve 121 is opened, and the air-fuel mixture flows into the combustion chamber 107 from the chamber 109 through the manifold 123, explodes upon ignition, and the exhaust air-fuel mixture is urged outward from the port 119.

[0005] The piston 103 and the additional piston 113 are located at the bottom dead center, the exhaust in the combustion chamber 107 is removed, the chamber 109 is compressed, and the chamber 117 is filled with the air-fuel mixture.

[0006] The pistons 103 and 113 move upward, and a new compression stroke starts.

[0007] When the piston 103 moves upward, the piston 103 closes the port 119, and all the air-fuel mixture supplied from the chamber 109 remains in the combustion chamber 107. The air-fuel mixture from the chamber 117 is added to this air-fuel mixture.

[0008] That is, the amount of the air-fuel mixture in the combustion chamber 107 is the total amount from the chambers 109 and 117, and it is assumed that the specific power of the engine is increased.

[0009] However, although the bores of the chambers 109 and 117 are common with that of the combustion chamber 107, the rod 115 that does not pass through the combustion chamber 107 is located.

[0010] Therefore, the volumes of the chambers 109 and 117 are both reduced according to the volume of the rod 115 with respect to the volume of the combustion chamber 107, and only the chamber 109 has insufficient intake air to the combustion chamber 107 and insufficient scavenging from the combustion chamber 107.

[0011] For this reason, the chamber 117 must be added and charged, and the structure becomes complicated. Further, when being charged from the chamber 117 to the combustion chamber 107, since the port 119 is closed, the scavenging from the combustion chamber 107 remains insufficient.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0013] The problem to be solved is that the structure for ensuring the intake air to the combustion chamber becomes complicated and the scavenging also becomes insufficient.

Means for Solving the Problems

[0014] The two-cycle engine of the present invention is a two-cycle engine provided with a combustion chamber and an intake chamber in order to enable accurate scavenging and intake with a simple structure. The two-cycle engine includes a first cylinder forming the combustion chamber, a second cylinder forming the intake chamber, a third cylinder communicating the first and second cylinders and forming a relay hole having a smaller diameter than the combustion chamber and the intake chamber, a piston disposed in the combustion chamber, a compression movable part disposed in the intake chamber, a shaft connecting between the piston and the compression movable part and reciprocally fitted and supported in the relay hole, an exhaust port for exhausting exhaust gas from the combustion chamber, and an intake port openable and closable according to the stroke of the piston. When the piston strokes toward the bottom dead center due to explosion expansion in the combustion chamber, the exhaust port and the intake port are opened, and intake air is introduced into the combustion chamber through the intake port from the intake chamber compressed by the compression movable part.

Advantages of the Invention

[0015] Since the two-cycle engine of the present invention has the above-described configuration, the shaft strokes in both the intake chamber and the combustion chamber, so that the influence of the shaft on the intake from the intake chamber to the combustion chamber is suppressed, and accurate scavenging and intake can be performed with a simple structure without adding an intake chamber.

Brief Description of the Drawings

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Figure 1

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Figure 5

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Figure 7

Figure 8

Figure 9

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Figure 12

Figure 13

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Figure 15

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Figure 17

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Figure 23

DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention has achieved the object of enabling accurate scavenging and intake with a simple structure as follows.

[0018] A two-cycle engine having a combustion chamber and an intake chamber, a first cylinder for forming the combustion chamber, a second cylinder for forming the intake chamber, a third cylinder for communicating the first and second cylinders and forming a relay hole having a smaller diameter than the combustion chamber and the intake chamber, a piston disposed in the combustion chamber, a compression movable part disposed in the intake chamber, a shaft connecting the piston and the compression movable part and reciprocally fitted and supported in the relay hole, an exhaust port for exhausting exhaust from the combustion chamber, and an intake port openable and closable according to the stroke of the piston, and when the piston strokes to the bottom dead center side due to explosion expansion in the combustion chamber, the exhaust port and the intake port are opened and intake is performed from the intake chamber compressed by the compression movable part into the combustion chamber through the intake port.

[0019] This two - cycle engine can be applied to automobiles, motorcycles, as well as construction machinery, agricultural vehicles, agricultural machinery, ships, aircraft, drones, chain saws, generators, etc.

[0020] The fuel applicable to this two - cycle engine is, for example, gasoline, but it is not limited to this and various fuels can be used. For example, instead of gasoline, hydrogen, biofuel, light oil, kerosene, synthetic fuel, etc. can also be used.

[0021] The shaft is provided with a passage - forming portion, and the passage - forming portion is realized in a form that opens the intake port to the intake chamber between the third cylinder and the shaft by the downward - stroke of the piston.

[0022] The passage - forming portion can be formed by a portion of the shaft having a diameter smaller than that of the relay hole, a groove formed in the shaft, a hole, etc.

[0023] The intake port is composed of a plurality of recesses formed at regular intervals in the circumferential direction, but it can also be replaced with a hole or a circumferential recess, etc.

[0024] The intake port only needs to be capable of opening and closing according to the stroke of the piston provided in the third cylinder, and can also be composed of an externally - connected hole formed in the third cylinder and an opening - closing valve provided in this hole.

[0025] The compression movable part includes a retainer valve fixed to the shaft and a valve body disposed between the shaft and the retainer valve in the stroke direction. The retainer valve is provided with a valve passage through which the intake received by the intake chamber passes. The valve body is attached between the shaft and the retainer valve so as to be relatively movable freely in the stroke direction, and closes the valve passage by relative movement toward the retainer valve side to partition the inside of the second cylinder into a front chamber and a rear chamber, and has a body passage that opens the valve passage by relative movement toward the shaft side to enable the intake to the front chamber to move to the intake chamber of the rear chamber.

[0026] It is realized in a form where intake air is directly injected into the intake chamber, or in a form where an intake passage with a valve is connected to the intake chamber through another route, and the compressible moving part can also be constituted by a simple auxiliary piston.

[0027] It is realized in a form including a crankshaft interlockingly coupled to the piston and a slider interlockingly coupled to the crankshaft and reciprocating in a direction intersecting the stroke direction of the piston to agitate oil for lubricating the piston.

[0028] The piston, the slider, and the crankshaft are realized in a form coupled by a spinner composed of eccentric integral first and second disk parts for forming a double-slider crank mechanism.

[0029] The slider can be omitted, and a conventional crank mechanism can also be used.

[0030] The formation of the double-slider mechanism is not limited to the coupling by a spinner, and can also be replaced by the coupling by an arm-shaped member.

[0031] The first disk part is internally supported rotatably relative to a first spinner support hole formed in the piston so that the axis is orthogonal to the stroke direction of the piston. The second disk part is internally supported rotatably relative to a second spinner support hole formed in the slider and having an axis in the same direction as the axis of the first spinner support hole. The first and second disk parts are eccentric according to the stroke of the piston, and the crankshaft is realized in a form where a crank pin is rotatably fitted to the spinner between the axes of the first and second disk parts.

[0032] An oil pan that houses the oil, and an oil hole that penetrates from the piston through the shaft and the retainer valve and opens into the front chamber of the intake chamber to communicate the oil pan with the front chamber, and the oil agitated in the oil pan reaches the front chamber through the oil hole.

Embodiment

[0033] [Two-stroke engine] (Cylinder) FIG. 1 is a partially cut-away perspective view of a two-stroke engine according to an embodiment. FIG. 2 is a cross-sectional view of the two-stroke engine of FIG. 1 in the explosion expansion stroke. FIG. 3 shows the scavenging stroke of the two-stroke engine of FIG. 1, where (A) is a cross-sectional view and (B) is an enlarged cross-sectional view of part B of (A). FIG. 4 shows the compression stroke of the two-stroke engine of FIG. 1, where (A) is a cross-sectional view and (B) is an enlarged cross-sectional view of part B of (A). FIG. 5 is a cross-sectional view corresponding to the arrow view along line V-V in the explosion expansion stroke of the two-stroke engine of FIG. 1. FIG. 6 is a cross-sectional view corresponding to the arrow view along line VI-VI in the explosion expansion stroke of the two-stroke engine of FIG. 1.

[0034] As shown in FIGS. 1 to 6, the two-stroke engine 1 has a configuration including a combustion chamber 3 and an intake chamber 5. This two-stroke engine 1 includes a first cylinder 7, a second cylinder 9, a third cylinder 11, a piston 13, a compression movable part 15, a shaft 17, an exhaust port 19, and an intake port 21.

[0035] The first cylinder 7 has an inner diameter of a predetermined bore for forming the combustion chamber 3. The first cylinder 7 is provided with the exhaust port 19 according to the bottom dead center of the piston 13. The exhaust port 19 discharges exhaust from the combustion chamber 3. The direction of the exhaust port 19 is orthogonal to the stroke direction of the piston 13.

[0036] The cross-sectional shape of the exhaust port 19 is composed of a substantially straight portion that opens into the combustion chamber 3 and a portion that gradually expands in the discharge direction continuous with this.

[0037] However, the orientation of the exhaust port 19 can be freely set in consideration of exhaust efficiency, etc., such as being inclined with respect to the stroke direction of the piston 13. Also, the cross-sectional shape of the exhaust port 19 can be freely set in consideration of exhaust efficiency and regulation of intake air leakage.

[0038] The first cylinder 7 is provided with an oil pan 23. Lubricating oil is stored in the oil pan 23. At one end of the first cylinder 7, a cylinder bottom plate 24 is fastened and fixed by bolts.

[0039] Cooling fins 7a are mainly set in the first cylinder 7 according to the combustion chamber 3. Note that including the second and third cylinders 9 and 11 described later, it is also possible to configure it as a water-cooled engine by replacing the cooling fins with a water jacket.

[0040] The second cylinder 9 is for forming the intake chamber 5. The inner diameter of the second cylinder 9 is set to be the same as or substantially the same as the inner diameter of the first cylinder 7. A head cover 25 is fastened and fixed to the second cylinder 9. A cover intake port 25a is formed in the head cover 25. For example, a motorcycle carburetor is connected to the cover intake port 25a as an unillustrated carburetor.

[0041] Note that it is also possible to perform EFI conversion or direct injection instead of the carburetor.

[0042] Cooling fins 9a are set in the second cylinder 9.

[0043] The third cylinder 11 is for forming the relay hole 27. The relay hole 27 communicates the first and second cylinders 7 and 9, and its inner diameter is formed to be smaller than that of the combustion chamber 3 and the intake chamber 5.

[0044] The third cylinder 11 is integrally formed with the second cylinder 9, and the end of the third cylinder 11 is butt-joined to the end of the first cylinder 7 by inlay and fastened and fixed by bolts.

[0045] An ignition chamber 11a is formed on the inner circumference of the end of the third cylinder 11. The ignition chamber 11a is formed with the same diameter as the combustion chamber 3 of the first cylinder 7 on the end face of the third cylinder 11 and reaches the relay hole 27 with a tapered surface that gradually reduces in diameter. A plug hole 29 faces the tapered surface of the ignition chamber 11a. A magnet ignition device (not shown) is attached to the plug hole 29. However, a battery ignition plug can also be used instead of the magnet ignition device. Note that power distribution to the ignition plug uses a distributor, but direct ignition can also be used. Also, when this engine is configured as a diesel engine, glow plug ignition and self-ignition can also be applied.

[0046] An intake port 21 is formed at the end of the relay hole 27 on the ignition chamber 11a side. The intake port 21 is formed by a recess facing the ignition chamber 11a and a plurality of intake ports 21 are provided at regular intervals in the circumferential direction. The shape and the like of the intake port 21 can be variously changed in consideration of intake efficiency and the like. The intake port 21 can be opened and closed as described later according to the stroke of the piston 13.

[0047] Cooling fins 11b are provided on the third cylinder 11.

[0048] (Piston) FIG. 7 is a perspective view showing the piston of the two-cycle engine of FIG. 1. FIG. 8 is a side view showing the piston of the two-cycle engine of FIG. 1. FIG. 9 is a cross-sectional view of the piston of the two-cycle engine of FIG. 1.

[0049] As shown in FIGS. 1 to 9, the piston 13 is integrally formed with the shaft 17. However, the piston 13 and the shaft 17 may be formed separately and integrally coupled to each other.

[0050] The piston 13 is disposed in the combustion chamber 3, has an outer diameter substantially the same as the inner diameter of the combustion chamber 3, and is supported so as to be strokable along the combustion chamber 3.

[0051] A tapered surface 13aa is formed at one end 13a of the piston 13. The tapered surface 13aa is formed with the same taper as the tapered surface of the ignition chamber 11a, and faces the tapered surface of the ignition chamber 11a with a gap at the top dead center of the piston 13.

[0052] Between one end 13a and the other end 13b of the piston 13, the side surface is formed with a two-sided width, and a crank chamber 31 is formed between the piston 13 and the first cylinder 7. The oil pan 23 is located in the crank chamber 31.

[0053] Sealing rings 33 and 35 are attached to one end 13a and the other end 13b of the piston 13.

[0054] A first spinner support hole 37 located in the crank chamber 31 is formed in the middle part of the piston 13. The axis of the first spinner support hole 37 is orthogonal to the stroke direction of the piston 13. Recesses 39 for weight reduction are formed on both sides of the first spinner support hole 37 in the middle part of the piston 13.

[0055] The operation of the piston 13 is taken out as rotational output by the crankshaft 40, and the oil in the crank chamber 31 is agitated by the reciprocating motion of the slider 41. The piston 13 and the slider 41 constitute a double-slider crank mechanism together with the crankshaft 40. The double-slider crank mechanism will be described later.

[0056] At the base of one end 13a of the piston 13, a radial oil hole 42 of the piston 13 is formed. The piston 13 is hollow and has an oil hole 43 in the stroke direction formed therein.

[0057] (Shaft) The shaft 17 is configured to connect between the piston 13 and the compression movable part 15. This shaft 17 has an outer diameter substantially the same as the inner diameter of the relay hole 27 of the third cylinder 11 and is fitted and supported so as to be reciprocable.

[0058] The shaft 17 is formed hollow, and an oil hole 45 in the stroke direction is formed in the axial center part. The oil hole 45 of the shaft 17 communicates with the oil hole 43 of the piston 13 and is formed with the same diameter.

[0059] The shaft 17 is provided with a passage forming part 47. The passage forming part 47 is configured to open the intake port 21 to the intake chamber 5 between the third cylinder 11 and the shaft 17 by the stroke of the piston 13 toward the bottom dead center side.

[0060] The passage forming part 47 is configured by relatively reducing the diameter of the tip of the shaft 17. By this passage forming part 47, a circumferential gap is formed with the relay hole 27. When the passage forming part 47 reaches the intake port 21 due to the stroke of the piston 13, the intake port 21 is opened to the intake chamber 5, and intake is performed from the intake port 21 to the combustion chamber 3.

[0061] An airtight ring 49 is attached adjacent to the passage forming part 47 on the tip side of the shaft 17.

[0062] Figure 10 relates to the retainer valve of the two - cycle engine of FIG. 1. (A) is a perspective view seen from the back side, and (B) is a perspective view seen from the front side. Figure 11 is a cross - sectional view of the retainer valve of the two - cycle engine of FIG. 1. Figure 12 relates to the valve body of the two - cycle engine of FIG. 1. (A) is a perspective view seen from the back side, and (B) is a perspective view seen from the front side. Figure 13 is a cross - sectional view of the valve body of the two - cycle engine of FIG. 1.

[0063] (Compression movable part) As shown in FIGS. 1 - 6 and FIGS. 10 - 13, the compression movable part 15 includes a retainer valve 53 and a valve body 55. The retainer valve 53 is fixed to the shaft 17, and the valve body 55 is disposed between the shaft 17 and the stroke direction of the retainer valve 53.

[0064] As shown in FIGS. 1 - 6, FIGS. 10, and 11, the retainer valve 53 has a valve head 53a and a valve shaft 53b integrally formed.

[0065] The outer diameter of the valve head 53a is set to be slightly smaller than the inner diameter of the second cylinder 9. The valve head 53a is provided with an oil hole 56 at the center and a valve passage 57 around the oil hole 56. The oil hole 56 of the valve head 53a is formed with a relatively small diameter and is set to allow an appropriate amount of oil to pass through. The valve passage 57 is configured to allow the intake air received by the intake chamber 5 from a carburetor (not shown) to pass through. The valve passage 57 is, for example, a hole penetrating in the stroke direction of the retainer valve 53, and a plurality of them are formed at predetermined intervals in the circumferential direction.

[0066] The valve shaft 53b is formed hollow, and an oil hole 58 is formed on the inner circumference. The oil hole 58 of the valve shaft 53b communicates with the oil hole 56 of the valve head 53a. The valve shaft 53b is tightly fitted to the tip of the shaft 17 through a hollow plug retainer 59. By this fitting, the oil hole 58 of the valve shaft 53b communicates with the oil hole 45 of the shaft 17.

[0067] Therefore, the oil holes 42, 43, 45, 56, and 58 are configured to penetrate through the piston 13 to the shaft 17 and the retainer valve 53 and open into the front chamber 61, thereby connecting the oil pan 23 to the front chamber 61. Due to this connection, the oil agitated in the oil pan 23 can reach the front chamber 61 through the oil holes 42, 43, 45, 56, and 58.

[0068] As shown in FIGS. 1 to 6, FIGS. 12, and FIGS. 13, the valve body 55 is configured to partition the inside of the second cylinder 9 into the front chamber 61 and the rear chamber 63. The valve body 55 is formed by integrally forming a closing disk 55a and a boss portion 55b.

[0069] The closing disk 55a abuts against the valve head 53a and is configured to open and close the valve passage 57 in a closable manner. A sealing ring 55ab is attached to the closing disk 55a and is in sliding contact with the inner surface of the intake chamber 5.

[0070] The boss portion 55b is set to have an axial length shorter than that of the valve shaft 53b and is fitted and attached to the valve shaft 53b. The inner diameter of the boss portion 55b is set to be larger than the outer diameter of the valve shaft 53b, and a body passage 55ba is formed in the boss portion 55b. The body passage 55ba is formed as a hole penetrating the boss portion 55b, and a plurality of body passages 55ba are provided at predetermined circumferential intervals. The body passage 55ba communicates with the gap between the valve body 55 and the valve shaft 53b.

[0071] The valve body 55 is attached so as to be relatively movable freely in the stroke direction between the shaft 17 and the retainer valve 53. The valve body 55 closes the valve passage 57 by moving relatively toward the retainer valve 53 side to partition the front chamber 61 and the rear chamber 63, and opens the valve passage 57 by moving relatively toward the shaft 17 side to enable the intake air to the front chamber 61 to move from the body passage 55ba to the intake chamber 5 of the rear chamber 63.

[0072] The after-chamber 63 is set such that the volume at the top dead center of the piston 13 is approximately the same as the volume of the combustion chamber 3 at the bottom dead center of the piston 13. However, such volume can also be made different by changing the inner diameter of the second cylinder 9 and the outer diameter of the valve body 55, etc.

[0073] Therefore, when the piston 13 strokes toward the bottom dead center due to the explosion expansion in the combustion chamber 3, the exhaust port 19 and the intake port 21 are opened, and intake air is drawn into the combustion chamber 3 from the intake chamber 5 where the compression movable part 15 compresses, through the intake port 21.

[0074] (Double-slider crank mechanism) FIG. 14 relates to the crankshaft of the two-cycle engine of FIG. 1. (A) is a perspective view seen from one side, and (B) is a perspective view seen from the other side. FIG. 15 is a cross-sectional view of the crankshaft of the two-cycle engine of FIG. 1. FIG. 16 relates to the slider of the two-cycle engine of FIG. 1. (A) is a perspective view seen from one side, and (B) is a perspective view seen from the other side. FIG. 17 is a cross-sectional view of the slider of the two-cycle engine of FIG. 1. FIG. 18 relates to the spinner of the two-cycle engine of FIG. 1. (A) is a perspective view seen from one side, and (B) is a perspective view seen from the other side. FIG. 19 is a cross-sectional view of the spinner of the two-cycle engine of FIG. 1. FIG. 20 relates to the bearing retaining cover of the two-cycle engine of FIG. 1. (A) is a perspective view seen from one side, and (B) is a perspective view seen from the other side. FIG. 21 is a cross-sectional view of the bearing retaining cover of the two-cycle engine of FIG. 1. FIG. 22 relates to the operation explanation of the double-slider crank mechanism of the two-cycle engine of FIG. 1. (A) is an explanatory view showing the fitting relationship between the spinner and the crank pin, (B) is an explanatory view seen from the side of the crankshaft, and (C) is an explanatory view seen from the axial direction of the crankshaft.

[0075] The piston 13 is interlocked and coupled with the crankshaft 40. The slider 41 is interlocked and coupled with the crankshaft 40 and is configured to reciprocate in a direction intersecting the stroke direction of the piston 13 to stir the oil for lubricating the piston 13. The stirred oil will also reach the front chamber 61 through the oil holes 42, 43, 45, 56, and 58 as described above.

[0076] The piston 13, the crankshaft 40, and the slider 41 are coupled by a spinner 65 for forming a double-slider crank mechanism.

[0077] As shown in FIGS. 1 to 6, FIG. 14, and FIG. 15, the crankshaft 40 has a shaft portion 40b projecting concentrically from a rotating portion 40a and includes a crank pin 40c eccentric with respect to the shaft portion 40b.

[0078] As shown in FIGS. 1 to 6, FIG. 16, and FIG. 17, the slider 41 is formed in a shape with a rectangular outer shape and cut corners, and has a second spinner support hole 41a in which the spinner 65 is inscribed. The second spinner support hole 41 has an axis in the same direction as the axis of the first spinner support hole 37.

[0079] As shown in FIGS. 1 to 6, FIG. 18, and FIG. 19, the spinner 65 is composed of eccentric integral first and second disk portions 65a and 65b. The first and second disk portions 65a and 65b are set to be relatively displaced along the radial direction and are eccentric according to the stroke of the piston 13. The first disk portion 65a is set to be thicker than the second disk portion 65b. A pin fitting hole 65c is formed between the axes of the first and second disk portions 65a and 65b in the spinner 65.

[0080] The spinner 65 has a first disk portion 65a that is internally supported in a relatively rotatable manner in a first spinner support hole 37 of the piston 13. A second disk portion 65b is internally supported in a relatively rotatable manner in a second spinner support hole 41a of the slider 41. The crankshaft 40 has a crank pin 40c that is relatively rotatably fitted in a pin fitting hole 65c between the axial centers of the first and second disk portions 65a and 65b.

[0081] The crankshaft 40 and the slider 41 are supported by the first cylinder 7 by a bearing retaining cover 67.

[0082] As shown in FIGS. 1 to 6, FIG. 20, and FIG. 21, the bearing retaining cover 67 has a rotation support portion 67b on a mounting flange 67a and a slider guide 67c on the side of the crank chamber 31 of the flange 67a.

[0083] The bearing retaining cover 67 is fastened and fixed to the first cylinder 7 by bolts, and a rotating portion 40a of the crankshaft 40 is rotatably supported by the rotation support portion 67b via a bearing 67d. A shaft portion 40b of the crankshaft 40 protrudes outside the bearing retaining cover 67, and an oil seal 67e is provided between the bearing retaining cover 67 and the shaft portion 40b.

[0084] The slider 41 is slide-guided by the slider guide 67c, and the slider 41 reciprocates orthogonally to the stroke direction of the piston 13.

[0085] The double-slider crank mechanism of the piston 13, the slider 41, and the crankshaft 40 in FIGS. 1 to 6 rotates the crankshaft 40 by the stroke of the piston 13 and causes the slider 41 to reciprocate along the slider guide 67c of the bearing retaining cover 67.

[0086] This will be described with reference to FIG. 22. As shown in FIG. 22(A), the crank pin 40c is fitted to the spinner 65 attached to the piston 13.

[0087] As shown in Fig. 22(B), the piston 13 repeats the cycle of returning from the top dead center at the left end, passing through the bottom dead center at the center, to the top dead center at the right end. By this cycle, the first disk portion 65a of the spinner 65 rotates as if from the left end to the right end within the first spinner support hole 37 along with the stroke of the piston 65. At this time, the second disk portion 65b of the spinner 65 eccentrically rotates about the crank pin 40c with respect to the first disk portion 65a.

[0088] As shown in Figs. 22(B) and (C), on the one hand, since the first disk portion 65a also has a stroke together with the piston 13 due to the rotation of the crank pin 40c, the second disk portion 65b operates so as to be orthogonal to the stroke direction of the piston 13 while rotating within the second spinner support hole 41a, and the piston 13 and the slider 41 perform the operation of the slider of the double-slider crank mechanism.

[0089] Therefore, the slider 41 reciprocates within the crank chamber 31 while being guided by the slider guide 67c of the bearing retaining cover 67, and stirs the oil within the crank chamber 31.

[0090] The oil within the crank chamber 31 lubricates the piston 13 by this stirring of the oil.

[0091] Also, the stirred oil also reaches the front chamber 61 through the oil holes 42, 43, 45, 56, 58 as described above. The oil that reaches this front chamber 61 lubricates the retainer valve 53a, the valve body 55, etc., and the oil that reaches the rear chamber 63 from the front chamber 61 lubricates the shaft 17, etc. When the oil that reaches the front chamber 61 mixes with the intake air from the carburetor, it reaches the combustion chamber 3 from the intake port 21 and burns together with the intake air. However, even if the oil reaches the combustion chamber, since the oil is not actively mixed with the intake air, the amount is almost none or very small.

[0092] [Operation of 2-cycle engine] As shown in FIGS. 1 and 2, when ignition is performed by an ignition device (not shown) of the spark plug hole 29 at the top dead center of the piston 13, the intake air in the combustion chamber 3 explodes and expands, and the piston 13 strokes to the bottom dead center as shown in FIG. 3(A).

[0093] When the piston 13 moves to the bottom dead center, first, the exhaust port 19 is opened, and the timing is such that the intake port 21 is opened later. That is, when the tapered surface 13aa of the piston 13 reaches the middle part of the exhaust port 19, as shown enlarged in FIG. 3(B), the passage forming part 47 of the shaft 17 reaches the intake port 21, and the intake port 21 is opened. Until the intake port 21 is opened, the intake air in the intake chamber 5 is compressed by the compression movable part 15 (the retainer valve 53 and the valve body 55).

[0094] At this timing, exhaust is performed from the exhaust port 19, and then the intake air in the rear chamber 63 that has been compressed by the compression movable part 15 is pressure-fed into the combustion chamber 3 through the intake port 21 as shown in FIG. 3(B), and scavenging in the combustion chamber 3 is performed.

[0095] [Operation and Effect] In the two-cycle engine of the embodiment of the present invention, when the piston 13 strokes toward the bottom dead center due to the explosion expansion in the combustion chamber 3, the exhaust port 19 and the intake port 21 are opened, and intake air is introduced into the combustion chamber 3 from the intake chamber 5 compressed by the compression movable part 15 through the intake port 21.

[0096] In this case, the shaft 17 that couples the piston 13 and the compression movable part 15 and is reciprocally fitted and supported in the relay hole 27 enters both the combustion chamber 3 and the rear chamber 63 of the intake chamber 5. Therefore, by appropriately setting the volumes of the combustion chamber 3 and the rear chamber 63, it is possible to eliminate or suppress the blowing out of insufficient intake air or excess intake air to the exhaust port, and it is possible to perform an appropriate combustion output with an appropriate intake air amount.

[0097] Since a plurality of intake ports 21 are provided at predetermined intervals in a circumferential manner with respect to the intake chamber 5, the intake from the intake ports 21 into the combustion chamber 3 can be made uniform in the circumferential direction and proceed in the stroke direction. Also, it has a structure that also serves to hold the outer diameter of the ring 49.

[0098] In the intake into the combustion chamber 3, since the volumes of the combustion chamber 3 and the rear chamber 63 are substantially the same, an appropriate amount of intake can be accurately performed from the rear chamber 63 into the combustion chamber 3.

[0099] Also in the scavenging of the combustion chamber 3, since the volumes of the combustion chamber 3 and the rear chamber 63 are substantially the same, the entire combustion chamber 3 can be smoothly scavenged by pumping the intake from the rear chamber 63 into the combustion chamber 3.

[0100] Since the direction of the exhaust port 19 is orthogonal to the stroke direction, leakage of the intake into the combustion chamber 3 from the exhaust port 19 can be suppressed.

[0101] Therefore, by performing appropriate scavenging and intake with respect to the combustion chamber 3 as a whole, accurate combustion can be realized.

[0102] The piston 13 is supported by the first cylinder 7, and the shaft 17 integrated with the piston 13 is supported by the third cylinder 11, so the pitching of the piston 13 is suppressed, and it is possible to suppress the sound vibration caused by pitching.

[0103] Moreover, the overall number of parts can be significantly reduced and the structure can be simplified, such as not requiring special valves other than the retainer valve 53 and the valve body 55 that also serve as the compression movable part 15.

[0104] The shaft 17 is provided with a passage forming portion 47. The passage forming portion 47 opens the intake port 21 with respect to the rear chamber 63 of the intake chamber 5 between the third cylinder 11 and the shaft 17 by the stroke of the piston 13 toward the bottom dead center side, so the intake into the combustion chamber 3 becomes unidirectional, and the intake can be smoothly and efficiently performed.

[0105] Since the compression movable part 15 uses the retainer valve 53 and the valve body 55, simple intake and compression of the intake air can be performed, and unidirectional intake can be surely performed.

[0106] It includes a crankshaft 40 linked and coupled to the piston 13, and a slider 41 linked and coupled to the crankshaft 40 and reciprocating in a direction intersecting the stroke direction of the piston 13 to stir the oil for lubricating the piston 13, constituting a double-slider crank mechanism.

[0107] Therefore, according to the stroke of the piston 13, the slider 41 can stir the oil in the crank chamber 31 to lubricate the piston 13.

[0108] In addition, the agitated oil also reaches the front chamber 61 through the oil holes 42, 43, 45, 56, 58. The oil reaching the front chamber 61 can also lubricate the retainer valve 53, the valve body 55, etc.

[0109] Therefore, there is no need to actively mix lubricating oil into the intake air, there is no or extremely little oil combustion, and the oil consumption peculiar to the two-stroke engine can be suppressed.

[0110] In the above, the single-cylinder two-stroke engine 1 is shown. However, by setting the intake chamber 5 etc. on both axial sides of the first cylinder 7 and making the intake structure, the combustion chamber 3, the piston 13, etc. symmetric in the stroke direction, a two-cylinder configuration can also be achieved. Also, a single-cylinder two-stroke engine or a two-cylinder two-stroke engine can be installed side by side and arranged crosswise, and by linking and coupling the cylinders installed side by side with a crankshaft for multiple cylinders at the part of the spinner 65, a multi-cylinder two-stroke engine such as a four-cylinder or an eight-cylinder can be easily formed.

Explanation of Reference Numerals

[0111] 1 Two-stroke engine 3 Combustion chamber 5 Intake chamber 7 First cylinder 9 Second cylinder 11 Third cylinder 13 Piston 15 Compression movable part 17 Shaft 19 Exhaust port 21 Intake port 23 Oil pan 27 Relay hole 31 Crank chamber 37 First spinner support hole 40 Crankshaft 40c Crank pin 41 Slider 41a Second spinner support hole 42, 43 Oil holes of piston 45 Oil hole of shaft 47 Passage forming part 53 Retainer valve 55 Valve body 55ba Body passage 56 Oil hole of valve head 57 Valve passage 58 Oil hole of valve shaft 61 Front chamber 63 Rear chamber 65 Spinner 65a First disk part 65b Second disk part

Claims

1. A two - cycle engine having a combustion chamber and an intake chamber, a first cylinder for forming the combustion chamber, a second cylinder for forming the intake chamber, a third cylinder for communicating the first and second cylinders to form a relay hole having a smaller diameter than the combustion chamber and the intake chamber, a piston disposed in the combustion chamber, a compression movable part disposed in the intake chamber, a shaft connecting between the piston and the compression movable part and reciprocally fitted and supported in the relay hole, an exhaust port for exhausting the exhaust from the combustion chamber, an intake port openable according to the stroke of the piston, comprising, when the piston strokes toward the bottom dead center due to the explosion expansion in the combustion chamber, the exhaust port and the intake port are opened, and intake air is drawn into the combustion chamber through the intake port from the intake chamber compressed by the compression movable part. A two - cycle engine.

2. The two - cycle engine according to Claim 1, wherein the shaft includes a passage forming part, and the passage forming part opens the intake port with respect to the intake chamber between the third cylinder and the shaft by the stroke of the piston toward the bottom dead center side. A two - cycle engine.

3. The two - cycle engine according to Claim 1, wherein the compression movable part includes a retainer valve fixed to the shaft and a valve body disposed between the shaft and the stroke direction of the retainer valve, the retainer valve includes a valve passage through which the intake air received by the intake chamber passes, the valve body is attached between the shaft and the retainer valve so as to be relatively movable freely in the stroke direction, closes the valve passage by relative movement toward the retainer valve side to partition the inside of the second cylinder into a front chamber and a rear chamber, and opens the valve passage by relative movement toward the shaft side to enable the intake air in the front chamber to move to the intake chamber of the rear chamber, and includes a body passage. A two - cycle engine.

4. The two - cycle engine according to Claim 3, a crankshaft interlockingly coupled to the piston, a slider interlockingly coupled to the crankshaft and reciprocating in a direction intersecting the stroke direction of the piston to agitate oil for lubricating the piston. A two - cycle engine comprising the above.

5. The two-cycle engine according to claim 4, wherein the piston, the slider, and the crankshaft are coupled by a spinner composed of eccentric, integral first and second disk portions for forming a double-slider crank mechanism. A two-cycle engine.

6. The two-cycle engine according to claim 5, wherein the first disk portion is internally supported rotatably relative to a first spinner support hole formed in the piston such that the axis thereof is orthogonal to the stroke direction of the piston. the second disk portion is internally supported rotatably relative to a second spinner support hole formed in the slider and having an axis in the same direction as the axis of the first spinner support hole. the first and second disk portions are eccentric according to the stroke of the piston. the crankshaft has a crank pin fitted rotatably relative to the spinner between the axes of the first and second disk portions. A two-cycle engine.

7. The two-cycle engine according to any one of claims 4 to 6, wherein an oil pan for containing the oil, an oil hole that penetrates from the piston through the shaft and the retainer valve and opens into the front chamber to communicate the oil pan with the front chamber. is provided, and the oil agitated in the oil pan reaches the front chamber through the oil hole. A two-cycle engine.

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