JPH02108856A - Starter for internal combustion engine - Google Patents

Abstract

PURPOSE:To make overall design compact by applying the constitution wherein a starter motor designed to have small capacity is mounted to a recoil starter fitted to the side of an engine body in such a way as to keep width approximately equal to the width of the recoil starter in the lengthwise direction of a crankshaft. CONSTITUTION:When a starter motor 16 is driven, a pinion 43, gears 45 and 46, a driven gear 39 and another pinion 38 are decelerated in sequence and the rotation is transmitted to a large gear 33. In addition, constitution is so made that a crankshaft 22 is rotated via the first clutch 35, thereby starting an internal combustion engine. Furthermore, constitution is so made that a starter wheel 30 is turned by pulling a knob 18 and taking out a rope 29, and the rotation thereof is transmitted from the second clutch 36 to a large reduction gear 30. Furthermore, the side of the crankshaft 22 is turned via the first clutch 35, thereby enabling the start of the engine. In addition, the starter motor 16 is so constituted that the width thereof in the lengthwise direction of the crankshaft 22 is approximately equal to the width of a coil starter casing 27.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an engine starting device, and particularly to one used in a four-stroke gasoline engine started by a starter motor.

BACKGROUND OF THE INVENTION FIG. 19 schematically shows a conventional starting device for a four-stroke gasoline engine of this type. Engine body (1)
A flywheel (4) integrally formed with a cooling fan (3) is attached to the crankshaft (2) which protrudes further. A ring gear (
5) is installed. A starter motor (6) whose main body has approximately the same length as the width of the engine main body (1) is attached to the side surface of the engine main body (1), and a drive shaft ( A drive gear (8) is fixed to 7). When the starter motor (6) is driven, the shaft (7) protrudes, the drive gear (8) meshes with the front ring gear (5), and the flywheel (4)
) to rotate the crankshaft (2). The latch structure is such that when the engine is started, the drive shaft (7) is retracted to its original state and disengaged from the ring gear (5). This starter motor (6
) is used by separately preparing a battery of any size for approximately half of the engine body (1) and connecting it to the starter motor (6).

Problems to be Solved by the Invention As mentioned above, a conventional four-stroke gasoline engine requires a starter motor (6) having a main body part with a width between the engine main body (1) and the starter motor (6). When the motor (6) was attached to the engine body (1), there was an inconvenience that the overall external size of the engine became very large. Additionally, in order to drive such a large starter motor (6), a similarly large power battery is required, and in the past, it was difficult to attach the battery to the engine body (1) as described above. However, there is a drawback that it must be kept separate. Furthermore, in the case of an engine mounted on a work machine, one with a recoil starter specification,
There are starter motor specifications, but starter motor specifications require special space to mount the battery, so, for example, it is easy to attach a starter motor specification engine to a recoil starter specification work machine. It is difficult to install and also has the disadvantage that wiring work between the battery and the starter motor is required.

In addition, some very small 2-cycle engines of 50cc or less have a small starter motor and battery attached to the engine body, but for 50cc to 250cc
In a small 4-stroke gasoline engine,
There was no such thing, and it was impossible.

This invention solves the above-mentioned disadvantages of the conventional four-stroke gasoline engine, and even when a starter motor is installed, the entire engine can be made compact, and the battery can also be integrated into the engine body. This is how it was done.

Means for Solving the Problems, that is, in order to achieve the above object, the first invention of this application provides a starter system for a four-stroke gasoline engine by setting the engine startable rotation range to a low rotation speed of 350 rpm or less. The motor capacity is made as small as possible, and the starter motor is attached to the recoil starter attached to the engine body so that the width is approximately the same as the width of the recoil starter in the crankshaft direction. shall be.

In the above, a power source battery can also be attached to the engine body side. Furthermore, by arranging the starter motor above the center of the crankshaft, it can be protected from mud and water below.

In addition, as a means to keep the engine starting rotation range to a low rotation range of 350 rpm or less, it is necessary to automatically reduce the pressure in the cylinder at low rotation speeds, to use a carburetor that obtains an appropriate air-fuel ratio in the low rotation range, and to reduce the engine speed. The carburetor should be designed to obtain an air-fuel ratio suitable for ignition without the need for choke operation in the engine speed range, the ignition speed of the ignition device should be lowered, and the timing at which ignition timing can be avoided at low engine speeds (for example, Possible methods include retarding the engine to near dead center (near dead center) and increasing the secondary voltage of the ignition coil, which can be achieved by using some or all of these.

Effects According to the configuration of the present invention described above, a compact structure can be obtained by housing the starter motor within the approximate width of the recoil starter. Also, the battery used for it is 1.2
It can be started by using 10 units with a capacity of about 100 V.
By attaching the battery itself to the engine body side, there is no need for wiring during use or when mounting on a work machine.

Embodiment FIGS. 1 and 2 show an elevation view of the entire engine showing an embodiment of the present invention, and with respect to the crankshaft center P,
This is an inclined four-stroke gasoline engine in which the cylinder centerline Q is inclined diagonally. A fuel tank (12) is located above the engine body (11) directly above the crankshaft center P.
is mounted, and an exhaust muffler (13) is mounted on the side above the cylinder head. A fan case (19) is attached to one side surface in the direction of the crankshaft center P, and a recoil starter (14) is further attached to the side surface of the fan case (19). A starter motor (16) is located between the recoil starter (14) and an air cleaner (15) located above the crankshaft center P and on the same side of the cylinder head as the recoil starter (14). , further below there is a battery.
(17) is attached.

Further, a handle (18) for pulling a starting lobe protrudes from the upper side of the recoil starter (14).

FIG. 3 shows the internal structure of the recoil starter (14) and fan case (19). At the end of the crankshaft (22) protruding from the engine body (11),
A flywheel (24) equipped with a cooling fan (23) is attached. A driven member (25) is fixed to the side surface of the flywheel (24) with a bolt (26) and protrudes into the dish-shaped recoil starter case (27). At the center of the ceiling of the recoil starter case (27), a starter wheel (30) with a rope (29) wound around a shaft (28) protruding from the ceiling is rotatably fitted. Furthermore, to the shaft (32) fixed to the end face of this shaft portion (28) via a screw (31),
The reduction gear (33) and the drive member (34) are fitted onto the outside so that they rotate together. This drive member (3
4) and the driven member (25) are connected to the first clutch (3).
5) are interlocked and connected to each other. Furthermore, the deceleration manual gear (33) and the starter wheel (30) are interlocked and connected to each other via a second clutch (36). These first and second clutches (35) (3
An intermediate shaft (37) is pivotally supported on the side of 6), that is, at an obliquely upper part of the crankshaft center P, and this intermediate shaft (37)
Next, a small-diameter intermediate pinion (38) that constantly meshes with the large gear (33), and another driven intermediate gear (39).
are installed so that they rotate together. Another third clutch (47) is provided between the intermediate pinion (38) and the intermediate shaft (37). Stark motor (
16) is a motor body (41) inside a motor case (40) formed integrally with a recoil starter case (27).
A drive pinion (43) is installed at the tip of the motor shaft (42) that protrudes from the motor body (41).
), the drive pinion (43) is connected to a gear (45) on a driven shaft (44) supported between the motor case (40) and the recoil starter case (27) extension.
A pinion (46) meshed with the driven wheel (44) and also mounted on the driven gear (37) is connected to the driven gear (3) on the intermediate shaft (37).
9).

In the configuration shown in FIG. 3 above, when the starter motor (16) is driven, the pinion (43) on the drive shaft (42)
) to the gears (45) (46) on the driven wheels (44)
, the driven gear (39) on the intermediate shaft (37) and the pinion (
38), the rotation is transmitted while being decelerated, and further from the pinion (38) on the intermediate shaft (37) to the large gear (38).
3) and is transmitted to the first clutch (35) between the driving member (34) and the driven member (25).
), the rotation is transmitted to the crankshaft (22) side,
The engine is started. When the engine is started,
Since the first clutch (35) is automatically disengaged, the drive member (34) side is not rotated from the crankshaft (22) side. Further, when starting by the starter motor (16), the third clutch (47) is in a connected state, but the second clutch (36) is connected from the large gear (33) side to the starter wheel (30) side. This starter wheel (30) does not rotate because it has a structure that does not transmit power to the starter wheel (30). On the other hand, if you pull the handle (18) and pull out the lobe (29), the starter wheel (3
0) is rotated, and this rotation is transmitted from the second clutch to the reduction master gear (30), which in turn is transmitted to the first clutch (35).
The crankshaft (22) side is turned more to start the engine.

At this time, rotation is transmitted from the large gear (33) side to the pinion (38) side that meshes with it;
) and the intermediate shaft (37) is a one-way clutch mechanism in which rotation is not transmitted to the intermediate shaft (37) side, and the recoil starter (14)
The starter motor (16) side is not rotated during starting.

As shown in FIG. 4, a battery (17) for driving the scooter motor (16) is a rechargeable dry battery (about 1.2V) inserted into a roughly hexagonal cylindrical case (49).
50) (50)... is designed to be installed by inserting 10 of them, and as shown in Fig. 5, engagement grooves (51) (51) are formed on both the upper and lower sides. There is. A retaining protrusion (52) made of a leaf spring that engages with one of the grooves (51) is attached to the side surface of the motor case (40), and a recoil starter case (27) is attached to the other side of the motor case (40). A lever (53) is attached to the side of the. This lever (53) is always biased by a spring (not shown) so that its distal end protrudes inside the member (54). Then, when the battery case (49) is inserted between the protrusion (52) and the lever (53), the groove (51) (5
1) to hold the case (49). At this time, the battery case (49) has positive and negative terminals (55) exposed on both sides of the upper groove (51), and also on the motor case (40) side. Correspondingly, the positive and negative terminals (56) are exposed and protrude, and when the battery case (49) is attached as described above, these terminals come into contact with each other and the battery (17) and a motor (16) are wired together. As mentioned above, the dry batteries (50) (50)... are rechargeable, and by rotating the lever (53) and taking out the battery case (49), you can easily use the commercial power supply. can be charged.

As shown in FIGS. 2 and 3, the scooter motor (
16) is connected to the recoil starter case (2) with its drive shaft (42) in the same direction as the crankshaft (22).
7), but its crankshaft (22
) direction is approximately the same width as the recoil starter case (27), and its width in the left and right direction is also determined by utilizing the punt space between the air cleaner (15) and the recoil starter (14). Accordingly, the battery (17) is also large enough to fit within the width of the recoil starter case (14). Since the starter motor (16) and battery (17) have become extremely compact in this way, even when they are installed in the engine, they can be housed very compactly.

As shown in FIG. 7, the starter motor (16) and battery (17) are connected to the recoil stark case (27).
) to Vi(fa), and these recoil starters (
14), a motor (16), and a battery (17) as an integrated unit.
Fix it to the side of the fan case (19) with bolts (59) (59) as shown in the figure. In this case, in FIG. 3, the driven member (2
5), the members outside the drive member (34) are integrated, and when installed, the first clutch (35)
) are connected to each other via.

FIG. 8 shows a normal recoil starter specification unit (61) that does not have such a starter motor (16) and battery (17), and inside the recoil starter case (27) is the unit (61) shown in FIG. Recoil starter wheel (30), IL Express Tatsujin A (33), with parts on the starter motor (16) side removed from the intermediate shaft (37),
A second clutch (36) is equipped, and this is connected to the starter motor specification unit (60) shown in FIG.
By attaching it to the side of the fan case (19), you can easily change from a starter motor specification engine to a recoil starter specification engine, or from a recoil starter specification engine to a starter motor specification engine. It is possible.

Figure 9 shows the scooter motor (16) and the motor shaft (42).
) is shown attached to the recoil starter case (27) in the same manner as described above, with the direction perpendicular to the crankshaft center P. Additionally, the battery (17) is also mounted horizontally. The starter motor (16) is very small compared to conventional ones, but its shape is larger in the direction of the motor shaft (42) than in the diameter direction; When attached in the crankshaft direction in FIG. 3, its tip protrudes at the same level as or slightly beyond the outer surface of the recoil starter case (27). Therefore, by installing the air cleaner (15) and the recoil starter (14) sideways, the dead space between the air cleaner (15) and the recoil starter (14) can be used to accommodate the air cleaner (15) and the recoil starter (14) so that they do not protrude completely. As shown in Fig. 1θ, accordingly, the drive pinion (43) of the motor shaft (42) and the driven gear (45) on the driven shaft (44) that meshes with the drive pinion (43) both use bevel gears. . Moreover, instead of such a bevel gear mechanism, it is also possible to use a worm and a worm gear.

FIGS. 11 and 12 show another embodiment of the present invention, in which a pull (18) of a recoil starter (14) is housed in a recoil starter case (27). By doing this, when the stark motor (16) is driven, the wheel (3) on the recoil scooter (14) side
0) rotates, and accordingly, the scooter motor (16) and recoil starter (14) are rotated.
) is advantageous in that the second clutch (36) between the two is not required. The pull (18) is folded inside the opening (63) formed on the side surface of the recoil starter case (29), and when performing a starting operation, the pull (18)
) is taken out from the opening (63) as shown in FIG. 13 and operated. In these embodiments, the motor shaft (42) of the scooter motor (16) is mounted so as to be orthogonal to the crankshaft center P as in FIG. As shown in FIG. 2, it may be mounted in the same direction as the crankshaft center P.

Next, the starter motor (16) and battery (17)
) to be small enough to fit within the width of the recoil starter (14) as described above, and to enable starting in a low rotation range of 350 rpm or less will be described.

As is well known, in order to turn the engine crankshaft during startup, it is necessary for the piston to survive the compression process near top dead center, and this requires an extremely large amount of force.

To solve this problem, the exhaust valve or intake valve is forcibly opened to release the compression. In the case of the present invention, an automatic decompression device is used that automatically releases the compression at low speed rotation. By this, the starter motor (
16) The required capacity can be reduced. As such an automatic decompression device, for example, the applicant of the present invention has disclosed Japanese Patent Application No. 5'9-11539 (Japanese Unexamined Patent Publication No. 60156976).
There is a centrifugal automatic decompression device that was filed as No. This device is a centrifugal weight that is displaced as the camshaft rotates.
The pin is used to move the bottle in the diametrical direction of the shaft and push the tappet up in the direction of releasing the compression.At low rotations, the centrifugal weight automatically moves in the direction of releasing the compression.
Decompression at startup can be obtained without any special operation.

Next, FIG. 14 shows the electric circuit of the ignition power supply device used in the present invention. In the figure, the secondary coil (66) of the ignition coil (65) and the spark plug (6
7) are connected in series. On the other hand, the primary coil (6
8), the collector and emitter side FJ'ta of the transistor (69) are connected to its primary coil (6th).
are connected in parallel. Similarly transistor (69)
The anode and cathode side terminals of the thyrisk (70) are connected in parallel to both ends of the thyrisk (70), and the anode side of the thyrisk (70) is further connected to the base of the transistor (69). Both terminals of the Zener diode (71) are connected in parallel to the anode and cathode side terminals of the thyrisk (70), and the anode side of the zener diode (71) is also connected to the gate terminal of the thyrisk (70). FIG. 15 shows the voltage waveform generated in the primary coil (68). The voltage generator used in this embodiment is a flywheel magnet type that generates an alternating current voltage as the flywheel rotates, and the generated voltage is the operating voltage of the Zener diode (71).
In a state of 0 or less, a voltage is applied to the base side of the transistor (69), and a current flows between the collector and emitter of the transistor (69). When the generated voltage exceeds the vO, a voltage is applied to the gate terminal of the Cyrisk (70), so a current flows between the anode and cathode of the Cyrisk (70) (in the direction of the broken arrow in the figure), and the transistor (69)
) decreases, and the current flowing between the collector and emitter of this transistor (69) is cut off. Therefore, a large secondary voltage is generated in the secondary coil (66), causing the spark plug (67) to ignite.

As shown in FIG. 15, the voltage generated at the primary coil (68) changes depending on the engine speed. For example, when the engine speed is about 250 rpm, the voltage generated at the Zener diode (71) changes. operating voltage vO. Therefore, the current flowing through the transistor (69) is not interrupted, and a large voltage cannot be generated in the secondary coil (66). Therefore, in this example,
A capacitor (72) as shown in the figure is provided in parallel with the Zener diode (71), and a detection circuit detects the peak point P of the voltage due to conversion of charging and discharging of the capacitor (72). During low rotations when only a low voltage is generated, a signal is generated at the peak point P of the voltage to release the conduction of the transistor (69), and the current in the primary coil (6th) is cut so that ignition can occur. I have to.

Next, in order to prevent reverse rotation (ke-notin) during low-speed starting, in this embodiment, the shape of the iron core (73) around which the ignition coil (65) is wound is changed in the flywheel magnet type ignition system. As shown in FIG. 16, the ignition timing at low speed rotation is retarded. That is, in FIG. 16, a U-shaped iron core (75) (76) facing each other is provided at its tip, facing the magnetic throat (74) of the flywheel (24).
73) is fixed, and an ignition coil (65) is wound around this iron core (73). In this embodiment, the length of the lip (75) located on the rear side of the flywheel (24) in the rotating direction is 2. , the length n of the other lip (76)
t, thereby making the primary coil (
The waveform of the generated voltage (68) is modified as shown in FIG. 17, and the amount of retardation at low rotations is made larger than that shown in FIG. 15. As shown in FIGS. 14 and 15 above, at low rotation speeds of about 25 Qrpm where the operating voltage is below 0, the voltage peak point P is detected and a cutoff signal is generated accordingly. However, in the waveform of FIG. 17, two peak points appear, a first peak point P and a second peak point P2. In this case, if the cutoff is made at the first peak point P1, the amount of retardation is still insufficient for the firing angle θ1 at the maximum rotation, and it is necessary to take a cutoff signal at the second peak point P2. By increasing the retardation amount Δθ=θ2θ1 at low rotations with respect to the maximum rotation range, it is possible to obtain a sufficient retardation amount that does not cause reverse rotation as described above. Detection of such a second peak point P2 is performed, for example, by determining whether the peak point is the first peak point or the second peak point, and based on the determination result of the determining means. This can be easily realized by using a microcomputer equipped with a control means for generating a cutoff signal for the transistor at the second peak point. Note that the specific retardation amount Δθ with respect to the maximum rotation performed in the example was 7 degrees.

In order to improve the ignition performance at low rotation speeds, in this embodiment, the voltage of the secondary coil (66) that fires the spark plug (67) is changed from the conventional 8KV/250 r p
rn to improve the ignition performance.

Now, even if it is possible to ignite at low rotation speeds without causing reverse rotation, if the carburetor cannot supply the appropriate amount of fuel with an air-fuel ratio into the cylinder at that low rotation speed. , unable to ignite. Therefore, in this embodiment, in order to obtain an appropriate air-fuel ratio sufficient for ignition at a low rotation speed of 350 rpm or less, the 18th
As shown in the diagram, the henchery part (79) of the carburetor (78)
The diameter D1 of the nozzle (80) is made smaller than that of the conventional one to increase the inflow velocity of this part and to ensure that the fuel is sucked up from the nozzle (80).

Also, the extraction position of the air jet (81) and the nozzle (8
0) By selecting an appropriate combination of shapes, an appropriate air-fuel ratio can be obtained at low rotation speeds, and even when the engine is cold, it is possible to start it reliably without performing a choke operation.

By using all or some of these means in appropriate combination, it is possible to start with a small torque in a low rotation range of 350 rpm or less, and accordingly, the required capacity of the starter motor (16) can be reduced. It is possible to make it warmer and smaller than the conventional one, and the battery can be made smaller as well.

Effects of the Invention As described above, according to the present invention, by making it possible to start at low rotation speed, the scooter motor can be miniaturized and mounted, and the scooter motor can be mounted on the same side as the recoil starter and within approximately the width of the recoil starter. This eliminates the inconvenience of the starter motor protruding outward and increasing its size.
The effect is that the entire engine becomes extremely compact. Moreover, by downsizing the motor, the battery can also be downsized, and these motors and batteries can be attached to the engine. In the invention of claim 2, by attaching the scooter motor and battery to the engine in this way, even when mounted on a working machine or used in a general-purpose engine, the wiring between the motor and battery can be avoided. This eliminates the need for special space and brackets for mounting the buff battery when mounting it on a work machine, and the starter motor specification and recoil starter specification can be used at almost the same level. It can be shared and stored in the same space. Furthermore, in the third invention of this application, since the stark motor is installed above the center of the crankshaft, general-purpose engines installed on the ground, etc., are free from dirt, dust, mud, water, etc. This has the effect of reducing the frequency of maintenance.

[Brief explanation of drawings]

Fig. 1 is a front view of the entire engine showing an embodiment of the present invention, Fig. 2 is a side view seen from the right side of Fig. 1, Fig. 3 is a cross-sectional plan view of the beam coil scooter and fan case portion, and Fig. 4 The figure is a perspective view of the buff battery, Figure 5 is a vertical sectional view of the main part showing the installed state of the battery, Figure 6 is a vertical sectional view of the main part of the terminal connection between the battery and the starter motor, and Figure 7 is the main part of the starter motor. A perspective view of a coil starter equipped with a motor and a battery; FIG. 8 is a perspective view of a conventional recoil starter;
Fig. 9 is a front view of the entire engine showing another embodiment of the present invention, Fig. 10 is a cross-sectional plan view of the recoil starter and starter motor portion in Fig. 9, and Fig. 11 shows another example of the recoil starter. Front view shown, Figures 12 and 13
The figures are a cross-sectional plan view of main parts of the recoil starter shown in Fig. 11, Fig. 14 is a power supply circuit of an ignition device showing an embodiment of the present invention, and Fig. 15 is an ignition device that performs ignition by a flywheel magnet method. FIG. 16 is a graph showing changes in the generated voltage, and FIG.
FIG. 17 is a graph showing the waveform of the generated voltage obtained by the power generation device of FIG. 16, FIG. 18 is a vertical cross-sectional view of the main part of the carburetor used in the embodiment of the present invention, and FIG. 19 is FIG. 1 is a cross-sectional plan view of a main part of an engine showing the structure of a conventional starter motor. (11)...engine body, (14)...recoil starter, (16)...starter motor, (17)...battery, (22)...crankshaft. Figure 2

Claims (1)

[Claims] In a 1- or 4-cycle gasoline engine, the capacity of the starter motor is made as small as possible by setting the engine startable rotation range to a low rotation of 350 rpm or less, and this starter motor is connected to the engine body. An engine starting device characterized in that the engine starting device is attached to a recoil starter attached to the side so that the width is approximately the same as the width of the recoil starter in the crankshaft direction. 2. The engine starting device according to claim 1, wherein the power source battery for the starter motor is attached to the recoil starter. 3. The engine starting device according to claim 1, wherein the starter motor is attached to the recoil starter above the center of the crankshaft.