Two-stroke gasoline chain saw

Abstract

The utility model belongs to the technical field of chain saws, and particularly relates to a two-stroke gasoline chain saw which is characterized in that when the two-stroke gasoline chain saw is started, a one-way oil pumping device is manually pressed, so that oil is pre-fed into a metering device, then a starter is pulled, and as gasoline is pre-stored in the metering device, when the starter is pulled, the one-way oil pumping device is started; gasoline in the meter can immediately enter a combustion chamber to start the two-stroke gasoline engine, and a choke valve does not need to be operated any more. According to the two-stroke gasoline chain saw, a choke valve is omitted, and a manual one-way oil pumping device is additionally arranged, so that the defects caused by the choke valve are overcome, the number of times of pulling a starter during starting is reduced, the using effects of easy starting and no oil stuffiness are achieved, convenient starting of the two-stroke gasoline chain saw is achieved, the oil stuffiness phenomenon caused by insufficient experience of a user is prevented, and the service life of the two-stroke gasoline chain saw is prolonged. And the user has a better use experience feeling.

Description

Technical Field

[0001] The utility model belongs to the technical field of chain saws, and particularly relates to a two-stroke gasoline chain saw. Background Art

[0002] A two-stroke gasoline chain saw is a cutting device driven by a two-stroke gasoline engine. The working cycle of the two-stroke engine includes two strokes. Among them, the first stroke: the piston moves upward from the bottom dead center. After three air holes (intake hole, exhaust hole and transfer hole) are simultaneously closed, the mixture gas entering the cylinder is compressed; when the intake hole is exposed, the combustible mixture gas flows into the crankcase. The second stroke: when the piston is compressed near the top dead center, the spark plug ignites the combustible mixture gas, and the expanding gas pushes the piston to move downward to do work. At this time, the intake hole is closed, and the combustible mixture gas sealed in the crankcase is compressed; when the piston approaches the bottom dead center, the exhaust hole opens, and the exhaust gas rushes out; then the transfer hole opens, and the pre-pressurized combustible mixture gas rushes into the cylinder to expel the exhaust gas and perform the gas exchange process.

[0003] Combined Figure 1 And Figure 2 As shown, at present, a choke valve 10 is provided in the carburetor of the two-stroke gasoline chain saw. The main function of the choke valve 10 is to improve the starting performance of the engine. The choke valve 10 is located at the air inlet of the carburetor. Its working principle is to operate through a choke control knob 101 installed on the rear side of the chain saw. When the engine is cold-started, the choke valve 10 appropriately closes part of the air inlet to increase the gasoline concentration of the mixture gas entering the cylinder, thereby improving the starting performance of the engine. After the engine runs normally, the choke valve 10 should be fully opened, otherwise the engine cannot run normally due to too rich mixture gas, and it will also cause excessive fuel consumption.

[0004] Based on the working principle of the choke valve 10, for the existing two-stroke gasoline chain saw, when starting, it is necessary to close the choke valve 10 to generate negative pressure in the air intake passage of the carburetor, and use this negative pressure to suck fuel from the fuel tank for the machine to ignite and start. Ideally, as long as the user hears the first sound of the machine ignition explosion, and then fully opens the choke valve 10 through the choke control knob 101, the machine can be started. However, in actual use, first, due to the lack of experience of the user, pulling one or two more times slightly will cause the chain saw to flood and be difficult to start; second, if the idle fuel volume of the carburetor is adjusted too large, it is extremely easy to flood under the influence of the above-mentioned negative pressure, resulting in difficult starting. Although the idle speed can be adjusted to supply a small amount of fuel to avoid flooding, there will be two disadvantages. One is that the idle speed requires pulling the starter more times to start, and pulling the starter is laborious and the user experience is extremely poor. The other is that it will cause insufficient fuel supply at idle speed during hot engine operation and difficult starting. Content of the Utility Model

[0005] The utility model aims to provide a two-stroke gasoline chain saw, so as to realize the convenient starting of the chain saw through the two-stroke gasoline chain saw, prevent the phenomenon of fuel choking caused by the lack of experience of the user, and enable the user to have a better use experience.

[0006] To achieve the above object, the utility model adopts the following technical solutions:

[0007] Provide a two-stroke gasoline chain saw, including a frame, on which a two-stroke gasoline engine, an ignition system, a fuel tank and a sawing mechanism are provided. The two-stroke gasoline engine includes a cylinder on the upper side and a crankcase on the lower side. The cylinder is provided with a fuel inlet and an exhaust gas outlet. A piston is arranged in the cylinder, and a crankshaft is arranged in the crankcase. The piston is connected to the crankshaft through a connecting rod; the sawing mechanism includes a guide plate and a chain. The chain is wound around the guide plate, and the crankshaft is connected to the chain through a power transmission device; a carburetor is arranged on the two-stroke gasoline engine. An air intake passage is arranged inside the carburetor. The inner port of the air intake passage is communicated with the fuel inlet on the cylinder, and an air filter is arranged at the outer port. A throttle valve is arranged at the inner port of the air intake passage. A fuel pump and a meter are also arranged in the carburetor. The fuel pump is communicated with the fuel tank through an oil inlet pipe, and the fuel pump is communicated with the meter through a needle valve. A main fuel supply hole and an idle fuel supply hole communicated with the meter are arranged on the side wall of the air intake passage; it also includes a one-way fuel pump arranged on the frame. The one-way fuel pump is communicated with the meter through a one-way fuel pump inlet pipe and is communicated with the fuel tank through a one-way fuel pump return pipe; a choke valve is not arranged inside the air intake passage at the inner side of the air filter.

[0008] Preferably, the one-way fuel pump includes a fixed seat, an oil inlet one-way valve and an oil outlet one-way valve are arranged in the fixed seat, and a recoverable rubber cap is arranged on the fixed seat. One end of each of the oil inlet one-way valve and the oil outlet one-way valve is respectively communicated with the inside of the recoverable rubber cap. The other end of the oil inlet one-way valve is communicated with the one-way fuel pump inlet pipe, and the other end of the oil outlet one-way valve is communicated with the one-way fuel pump outlet pipe.

[0009] Preferably, the fixed seat is provided with a buckle, and a mounting card hole is correspondingly arranged on the frame.

[0010] Preferably, the fixed seat is provided with an external thread, and a mounting screw hole is correspondingly arranged on the frame.

[0011] Preferably, the exhaust gas outlet on the cylinder is communicated with a muffler.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows: When starting the two-stroke gasoline chain saw, first manually press the one-way fuel pump to pre-fill the fuel meter with fuel, and then pull the starter. Since the fuel meter has pre-stored gasoline, when pulling the starter, the gasoline in the fuel meter can immediately enter the combustion chamber to start the two-stroke gasoline engine, and there is no need to operate the choke valve anymore. By canceling the choke valve and adding a manual one-way fuel pump, the two-stroke gasoline chain saw solves the drawbacks brought by the choke valve, reduces the number of times of pulling the starter during starting, achieves the use effects of easy starting and no fuel choking, realizes the convenient starting of the two-stroke gasoline chain saw, prevents the fuel choking phenomenon caused by the lack of experience of the user, and enables the user to have a better use experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings are used to provide a further understanding of the present utility model, and constitute a part of the specification. Together with the embodiments of the present utility model, they are used to explain the present utility model, and do not constitute a limitation to the present utility model. In the drawings:

[0014] Figure 1 It is a schematic structural diagram of a prior two-stroke gasoline chain saw.

[0015] Figure 2 -(1) is a physical diagram of a prior two-stroke gasoline chain saw; Figure 2 -(2) is Figure 2 -a partial enlarged view of (1).

[0016] Figure 3 It is a schematic structural diagram of the two-stroke gasoline chain saw of the present utility model.

[0017] Figure 4 It is a schematic diagram of the connection between the one-way fuel pump and the carburetor in the two-stroke gasoline chain saw of the present utility model.

[0018] Figure 5 -(1) is a physical diagram of the two-stroke gasoline chain saw of the present utility model; Figure 5 -(2) is Figure 5 -a partial enlarged view of (1).

[0019] Figure 6 It is a schematic diagram of the use of the one-way fuel pump in the two-stroke gasoline chain saw of the present utility model.

[0020] In the figure, each reference numeral indicates the following: choke valve 10, throttle control knob 101, frame 20, fuel tank 30, cylinder 40, fuel inlet 401, exhaust gas outlet 402, piston 403, connecting rod 404, combustion chamber 405, spark plug 406, scavenging passage 407, crankcase 50, crankshaft 501, guide plate 60, chain 601, power transmission device 602, carburetor 70, intake passage 701, air filter 702, throttle valve 703, fuel pump 704, meter 705, needle valve 707, main fuel supply hole 708, idle fuel supply hole 709, one-way fuel pump 80, one-way fuel pump inlet pipe 801, one-way fuel pump return pipe 802, fixed seat 803, inlet one-way valve 804, outlet one-way valve 805, recoverable rubber cap 806, silencer 90, starter 100, and ignition switch 200. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] In one embodiment, a two-stroke gasoline chain saw is provided, as Figure 5 shown. The two-stroke gasoline chain saw includes a frame 20, which is a support frame for assembling the components of the two-stroke gasoline chain saw. As Figure 3-4 shown, a two-stroke gasoline engine, an ignition system, a fuel tank 30, and a sawing mechanism are provided on the frame 20. The ignition system is used to ignite the compressed fuel in the two-stroke gasoline engine. The fuel tank 30 is used to supply fuel to the two-stroke gasoline engine. The two-stroke gasoline engine drives the sawing mechanism to operate. A starter 100 and an ignition switch 200 are further provided at the rear side of the two-stroke gasoline engine, which are used for starting and shutting down respectively. Among them, as Figure 3As shown, the two-stroke gasoline engine includes a cylinder 40 on the upper side and a crankcase 50 on the lower side. The cylinder 40 is provided with a fuel inlet 401 and an exhaust gas outlet 402. A piston 403 is arranged inside the cylinder 40. The upper part of the piston 403 is a combustion chamber 405. A crankshaft 501 is arranged inside the crankcase 50. The piston 403 is connected to the crankshaft 501 through a connecting rod 404. A scavenging passage 407 is arranged between the crankcase 50 and the inside of the cylinder for allowing the air inside the crankcase 50 to enter the combustion chamber 405. The ignition system includes a spark plug 406, and also includes a magneto and a boost module (not shown in the figure) driven by the two-stroke gasoline engine for supplying power to the piston 406. The sawing mechanism includes a guide plate 60 and a chain 601. The chain 601 is wound around the guide plate 60. Blades are arranged on the chain 601. The crankshaft 501 is connected to the chain 601 through a power transmission device 602. The power transmission device 602 in this embodiment is a sprocket matched with the chain 601. A carburetor 70 is arranged on the two-stroke gasoline engine. An air intake passage 701 is arranged inside the carburetor 70. The inner port of the air intake passage 701 is communicated with the fuel inlet 401 on the cylinder 40, and an air filter 702 is arranged at the outer port. A throttle valve 703 is arranged at the inner port of the air intake passage 702. A fuel pump 704 and a meter 705 are also arranged in the carburetor 70. The fuel pump 704 is a diaphragm fuel pump. The meter 705 is used to adjust the fuel injection amount for each combustion. The fuel pump 704 is communicated with a fuel tank 30 through a fuel inlet pipe 706, and the fuel pump 704 is communicated with the meter 705 through a needle valve 707. The needle valve 707 is used to adjust the fuel amount of the meter 705. A main fuel supply hole 708 and an idle fuel supply hole 709 communicated with the meter 705 are arranged on the side wall of the air intake passage 702. The idle fuel supply hole 709 is located inside the throttle valve 703, and the main fuel supply hole 708 is located outside the throttle valve 703. The two-stroke gasoline chain saw further includes a one-way fuel pump 80 arranged on a frame 20. The one-way fuel pump 80 is a manual fuel pump. The one-way fuel pump 80 is communicated with the meter 705 through a one-way fuel pump inlet pipe 801 and is communicated with the fuel tank 30 through a one-way fuel pump return pipe 802. And compared with the existing two-stroke gasoline chain saw, a choke valve is not arranged inside the air filter 702 in the air intake passage 701 in this embodiment.

[0023] The working mode of the two-stroke gasoline chain saw is as follows: Combining Figure 3 and Figure 5As shown in the figure, when starting the two-stroke gasoline chain saw, first manually press the one-way fuel pump 80 to pre-fill the fuel meter 705 with fuel. Then pull the starter 100. Since the fuel meter 705 pre-stores gasoline, when pulling the starter 100, the gasoline in the fuel meter 705 can immediately enter the combustion chamber 405 to start the two-stroke gasoline engine, and there is no need to operate the choke valve, solving the problems of easy fuel choking and difficult idling start of the two-stroke gasoline chain saw. It can be seen that by canceling the choke valve and adding a manual one-way fuel pump to the two-stroke gasoline chain saw, the disadvantages brought by the choke valve are solved, the number of times of pulling the starter during startup is reduced, the usage effects of easy starting and no fuel choking are achieved, the problems of difficult starting and easy fuel choking during startup are solved, the convenient startup of the two-stroke gasoline chain saw is realized, the phenomenon of fuel choking caused by insufficient experience of the user is prevented, and the user has a better usage experience.

[0024] Further, in another embodiment, as Figure 6 shown, the one-way fuel pump 80 of the two-stroke gasoline chain saw includes a fixed seat 803. An inlet check valve 804 and an outlet check valve 805 are provided in the fixed seat 803. Valve holes corresponding to the inlet check valve 804 and the outlet check valve 805 are provided in the fixed seat 803. A recoverable rubber cap 806 is provided on the fixed seat 803. The recoverable rubber cap 806 is sealed with the fixed seat 803. One end of each of the inlet check valve 804 and the outlet check valve 805 is respectively communicated with the inside of the recoverable rubber cap 806. The output end of the inlet check valve 804 is communicated with the inside of the recoverable rubber cap 806. The input end of the outlet check valve 805 is communicated with the inside of the recoverable rubber cap 806. The other end of the inlet check valve 804 is communicated with the one-way fuel pump inlet pipe 801. The other end of the outlet check valve 805 is communicated with the one-way fuel pump outlet pipe 802.

[0025] Combined with Figure 4 and Figure 6 shown, the usage method of the one-way fuel pump 80 of the two-stroke gasoline chain saw is as follows: When pressing down along direction a, the inside of the recoverable rubber cap 806 is compressed. When releasing the pressure on the recoverable rubber cap 806, the recoverable rubber cap 806 returns along direction b, and a negative pressure is generated inside the recoverable rubber cap 806. The fuel meter 705 is evacuated through the one-way fuel pump inlet pipe 801. A negative pressure is generated inside the fuel meter 705. Further, the fuel pump 704 is evacuated through the needle valve 707, and a negative pressure is generated in the fuel pump 704. Further, gasoline in the fuel tank 30 is sucked through the inlet pipe 706. In other embodiments, the one-way fuel pump of the two-stroke gasoline chain saw can also adopt the finished product of the manual fuel pump on the current market.

[0026] Further, in one embodiment, the fixed seat 803 of the one-way oil pump 80 in the two-stroke gasoline chain saw is provided with an external thread, and a mounting screw hole is correspondingly provided on the frame 20, so that the one-way oil pump 80 is mounted on the frame 20 by means of threaded connection. In other embodiments, a buckle may also be provided on the fixed seat, and a mounting card hole is correspondingly provided on the frame.

[0027] Further, in one embodiment, an exhaust gas outlet 402 on the cylinder 40 of the two-stroke gasoline chain saw is communicated with a silencer 90 for reducing noise.

[0028] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A two-stroke gasoline chain saw, comprising a frame, on which a two-stroke gasoline engine, an ignition system, a fuel tank and a sawing mechanism are arranged, the two-stroke gasoline engine comprising an upper cylinder and a lower crankcase, the cylinder being provided with a fuel inlet and an exhaust gas outlet, a piston being arranged in the cylinder, a crankshaft being arranged in the crankcase, the piston being connected to the crankshaft through a connecting rod; the sawing mechanism comprising a guide plate and a chain, the chain being wound around the guide plate, the crankshaft being connected to the chain through a power transmission device; The two-stroke gasoline engine is provided with a carburetor, an air intake passage is provided inside the carburetor, an inner port of the air intake passage is communicated with a fuel inlet on the cylinder, an outer port is provided with an air filter, a throttle is provided at the inner port of the air intake passage, an oil pump and a meter are also provided in the carburetor, the oil pump is communicated with the fuel tank through an oil inlet pipe, the oil pump is communicated with the meter through a needle valve, a main oil supply hole and an idle oil supply hole communicated with the meter are provided on the side wall of the air intake passage; the characteristics are as follows: It also includes a one-way oil pump arranged on the frame, which is connected to the meter through an oil inlet pipe of the one-way oil pump and connected to the fuel tank through an oil return pipe of the one-way oil pump; the air intake area of ​​the air intake duct located inside the air filter in the air intake duct is not provided with a choke.

2. The two-stroke gasoline chain saw according to claim 1, characterized in that: The one-way oil pump includes a fixing seat, in which an oil inlet one-way valve and an oil outlet one-way valve are arranged, and a recoverable rubber cap is arranged on the fixing seat. The oil inlet one-way valve and the oil outlet one-way valve each have one end connected to the inside of the recoverable rubber cap respectively, and the other end of the oil inlet one-way valve is connected to the oil inlet pipe of the one-way oil pump, and the other end of the oil outlet one-way valve is connected to the oil outlet pipe of the one-way oil pump.

3. The two-stroke gasoline chain saw according to claim 2, characterized in that: The fixing seat is provided with a buckle, and the frame is correspondingly provided with a mounting hole.

4. The two-stroke gasoline chain saw according to claim 1, characterized in that: The exhaust gas outlet on the cylinder is connected with a muffler.

Images