JP2003065190A - Recoil starter of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rapid increase in pulling force of a pull rope of a recoil starter in an engine compression stroke in starting an engine by the recoil starter, to smooth the pulling force of the rope, and to increase a start number of revolutions of the engine to facilitate an engine start by assisting the pulling force by spring force of a power spring accumulated previously and an auxiliary cam when exceeding the compression stroke. SOLUTION: A pull rope reel and a crankshaft of the engine are engaged by a second ratchet mechanism capable of releasing engagement by centrifugal force, a wire is wound around an eccentric grooved cam integrated with an intermediate shaft cylinder linked to the pull rope reel by a first ratchet, the wire is pulled in one direction by a tension spring, and the wire and the tension spring make the eccentric grooved cam apply torque in a direction reduces a peak of fluctuation torque of a crank of the engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recoil starter used for starting a small internal combustion engine, and more particularly to a recoil starter provided with a mainspring or the like for relaxing crank fluctuating torque and facilitating manual starting. Regarding the device.

[0002]

2. Description of the Related Art A recoil starter disclosed in Japanese Utility Model Laid-Open No. 2-149872 is provided with a drive unit for rotating a crankshaft via a one-way clutch, and is rotated by being mounted between the drive unit and the clutch. A coil spring for transmitting a force is provided, which alleviates a sudden increase load in the compression process of the engine and increases the rotation speed in the expansion process of the engine to facilitate ignition start of the engine. Also, the actual fair 6-16
The recoil starter disclosed in Japanese Patent No. 964 is a recoil starter in which a centrifugal ratchet cam is used to transmit the rotation of the reel to a pulley on the engine side, and the cam is rotatably attached to the outer periphery of a boss portion that extends the bearing portion of the reel. ,
It is a recoil starter in which a reel and the cam are connected by a damper spring.

[0003]

[Problems to be Solved by the Invention] Japanese Utility Model Laid-Open No. 2-14987
In the recoil starter disclosed in No. 2, a coil spring is used for accumulating force, but the coil spring cannot obtain a sufficient amount of accumulating force. Further, in the recoil starter disclosed in Japanese Utility Model Publication No. 6-16964, since the damper spring that connects the reel and the cam is a coil spring housed in a small space, there is a problem that the damper ability cannot be sufficiently exhibited. The present invention, when starting the engine with a recoil starter,
During the engine compression stroke, avoid the pulling force of the recoil starter pull rope from suddenly increasing, and when the compression stroke is exceeded, assist the pulling force with the spring force of the spring and the auxiliary cam that have been stored in advance. The purpose of this is to make the pulling force of the rope smooth and to speed up the engine starting rotation speed to facilitate engine starting.

[0004]

In order to solve the above problems, the solution means of the present invention has the characteristics described in the following items. (1) A pull rope reel rotatably fitted to a shaft provided in a cover case of the recoil starter, and a pull rope wound around the pull rope reel and unwound by the restoring force of the first spring. In a recoil starter for starting an engine by pulling a pull rope and rotating a pull rope reel, one ratchet pawl that can be disengaged by a centrifugal force attached to a crankshaft of the engine and the ratchet pawl provided on the cover case A connecting shaft which is an extension of the connected shaft, one protrusion that engages with the ratchet pawl, and an eccentric groove cam. The connecting shaft is rotatably fitted to the inside of the cylinder near the pull rope reel. An intermediate shaft cylinder having a cylindrical portion formed with a large number of protrusions, a pull rope reel rotatably fitted to a shaft provided in the cover case, The pressing plate sandwiched between the shaft provided in the cover case and the joint shaft and the eccentricity that is attached to the side surface of the pull rope reel and spreads outward due to the frictional force with the pressing plate when the pull rope reel is on the drive side. A reel ratchet having a ratchet pawl that engages with the inner projection of the cam shaft cylinder; and a wire slidably wound around the eccentric groove cam,
A tension spring for pulling the wire in one direction, and the wire determines a relative angular position with respect to the engine crank so that the tension spring causes a torque to be applied to the eccentric groove cam in a direction to reduce the peak of fluctuation torque of the crank of the engine. Engine recoil starter with a structure attached to the cover case.

(2) In the recoil starter described in (1), the intermediate shaft cylinder is engaged with the ratchet pawl 1
An eccentric cam shaft cylinder that is provided with individual projections and an eccentric groove cam and is rotatably fitted to the joint shaft and does not have a cylindrical portion formed with a protrusion; and a pull rope that is rotatably fitted to the joint shaft. The reel-side cylinder is divided into a cylindrical portion having a large number of projections formed inside and a mainspring cover having a mainspring-storing cylindrical portion near the crankshaft, and these are joined together via a second mainspring. However, the recoil starter of the engine is configured so that unevenness of the torque at the time of starting is mitigated and the power is saved. (3) In the recoil starter according to the above (1) and (2), a wire wound around the eccentric groove cam and a tension spring that pulls the wire in one direction have a cam follower that engages with the eccentric groove cam. The eccentric groove cam was configured with a cam actuating lever attached to the cover case by deciding the relative angular position with respect to the engine crank so that the load is applied via the elastic body in the direction to reduce the peak of the fluctuation torque of the engine crank. Engine recoil starter.

[0006]

DETAILED DESCRIPTION OF THE INVENTION

[First Embodiment] A recoil starter according to a first embodiment of the present invention will be described with reference to the drawings. 1 is a side sectional view of a recoil starter, FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing a first ratchet mechanism, and FIG. 3 is an eccentric groove cam of an intermediate shaft cylinder and a ring shape wound around the eccentric groove cam. 1 shows a starting torque mitigating mechanism formed by a spring for pulling the wire of FIG.
It is a B sectional view. In the present description, the one applied to a small two-cycle engine will be described as an example.

In the drawing, 2 indicates a crank of a two-cycle engine. Reference numeral 23 is a crankcase that supports the crank 2 on both sides via ball bearings and has a space in which the crank 2 can freely rotate. 24 is the crankcase 2
3 is a cover case which is combined with 3 to accommodate the recoil starter 10 therein. A pull rope reel shaft 24a sharing a center line with the rotation shaft 2a of the crank 2 is provided on the central side surface of the cover case 24. Pull rope reel shaft 24
A pull rope reel 35 is rotatably fitted in a. The pull rope 29 is wound around the pull rope reel 35, the pull rope 29 is pushed through the cover case 24, and is coupled to the starter grip 11 installed outside the cover case 24. When the engine is started, the starter grip 11 is pulled. As a result, the pull rope 29 is pulled, the pull rope reel 35 is rotated, and the starter grip 1
When 1 is removed, the pull rope 29 is rewound on the pull rope reel 35 by the restoring force of the first spring 27.

The outer end of the first spring 27 is bent and fixed to a protruding rod 24b provided in the cover case 24,
The inner end of the first mainspring 27 is bent and fixed to a protruding rod 35 a provided on the pull rope reel 35.
Further, the end of the pull rope 29 is stopped by providing a bump inside the groove bottom through a hole or a notch formed in the groove bottom of the pull rope reel 35.

A joint shaft 31 is concentrically screwed to the pull rope reel shaft 24a and fixed by sandwiching a pressing plate 41, and an intermediate barrel 25 is rotatably fitted to the joint shaft 31. As shown in FIG. 2, the cylindrical portion 25 of the intermediate barrel 25
A protrusion 25a is provided inside d. When the pull rope reel 35 starts the engine, the pull portion 25a has a frictional force with respect to the pressing plate 41 that is greater than the friction force of the pull rope reel 3.
The first ratchet mechanism that rotates the pull rope reel 35 and the intermediate shaft cylinder 25 together is engaged by the ratchet pawl 42 that is adapted to be projected from the pull rope reel 35 by the centrifugal force caused by the rotation of 5. Is forming. The ratchet pawl 42 is swingable by a pin 55 fixed to the pull rope reel 35, and at the same time, the pull rope reel 3
The ratchet pawl 42 is urged toward the center of rotation by a torsion spring 56 supported by a pin 35b fixed to 5. When the pull rope 29 is unwound, a reverse frictional force acts between the ratchet pawl 42 and the pressing plate 41,
The ratchet pawl 42 is pulled in to a position where the ratchet pawl 42 inside the pull rope reel 35 does not engage with the protruding portion 25a of the intermediate barrel 25.

An eccentric groove cam 25b is provided on the intermediate barrel 25. A ring formed on an extension of the steel wire forming the tension spring 26 is wound around the eccentric groove cam 25b, and the end of the tension spring 26 is pin 28 sandwiched between the crankcase 23 and the cover case 24. Hanging on
When the pull rope reel 35 rotates and the eccentric groove cam 25b of the intermediate shaft cylinder 25 is rotated, the pulling force on the pull rope reel 35 changes depending on the eccentric position of the eccentric groove cam 25b, and the eccentric groove cam 25b and the tension spring 26 are moved. With a looped wire, select a material that reduces frictional force,
Positive and negative torques act on the intermediate barrel 25.

A ratchet support plate 15 is attached to the crankshaft 2a and tightened with a nut 19, a ratchet pawl 16 is rotatably fitted to a pin 17 fixedly mounted on the ratchet support plate 15, and is stopped by a retaining ring 18. ing. The ratchet pawl 16 is pushed by a torsion spring 20 so that the tip of the pawl is directed in the axial centerline direction. The intermediate shaft cylinder 25 is provided with one protrusion 25c with which the ratchet pawl 16 engages, and when the crankshaft 2a is stopped or rotates at a low speed, the ratchet pawl 16 engages with the protrusion 25c to rotate the crankshaft. Is raised, the ratchet pawl 16 forms a second ratchet mechanism that is disengaged by centrifugal force. The second ratchet mechanism engages in the starting rotation direction from the pull rope reel 35, but does not engage in rotation in the direction opposite to the start of the pull rope reel 35.

In FIG. 8, when the crank 2 rotates, the pull rope pulling force FA in the piston compression stroke due to the change in the rotation angle of the crank 2 is indicated by a one-dot chain line, and the calculated value of the pull rope pulling force by the eccentric groove cam 25b and the tension spring 26 is shown. FB is indicated by a broken line (the frictional force between the eccentric groove cam 25b and the wire looping the tension spring 26 is neglected). Also, F
C is a composite value of FA and FB. TDC indicates the top dead center of the piston, and the angle between the two TDCs is 1 of the crank 2.
Rotation (1 cycle of a 2-cycle engine) is shown. Since the number of ratchet pawls 16 attached to the ratchet support plate 15 is one, and the number of protrusions 25c of the intermediate shaft cylinder 25 is one, the angular position at which the second ratchet mechanism engages is always constant with respect to the crank 2. is there. If the relative angular position between the crank 2 and the protrusion 25c of the intermediate shaft cylinder 25 is appropriately determined, the peak of the pull rope pulling force FA in the piston compression stroke is suppressed and a smooth pulling force is obtained, as shown by the solid line FC in FIG. Can be obtained.

When the starter grip 11 is pulled, the crank 2 easily and smoothly starts to rotate due to the pulling force with which the peak pressure in the compression stroke is suppressed, and inertial force is applied to the crank 2 to cause the crank 2 to rotate.
Becomes high speed and the engine starts. When the engine starts and the rotation of the crank 2 increases and the rotation speed of the crankshaft 2a exceeds the rotation speed of the intermediate shaft cylinder 25, the ratchet pawl 16 disengages from the protrusion 25c of the intermediate shaft cylinder 25, and the rotation speed further increases. Then, the ratchet pawl 16 is attached to the inner circumference of the support plate 15 by the centrifugal force to completely release the engagement of the second ratchet mechanism.

[0014]

Second Embodiment A recoil starter 30 according to a second embodiment of the present invention is a recoil starter 1 according to the first embodiment.
The pull rope reel side and the eccentric groove cam side of the intermediate shaft cylinder 25 of No. 0 are divided, and both are connected via a buffer spring. The recoil starter 30 will be described below with reference to the drawings. 4 is a side sectional view of the recoil starter, FIG. 2 is a sectional view of the first ratchet mechanism taken along the line AA of FIG. 4 (shared with FIG. 1), and FIG. 3 is an eccentric groove cam of the intermediate shaft cylinder and this eccentric groove cam. FIG. 5 is a cross-sectional view taken along the line BB in FIG. 4 (shared with FIG. 1) showing a starting torque alleviating mechanism formed by a spring that pulls a ring-shaped wire wound around the coil. It should be noted that this description also exemplifies a case where it is applied to a small two-cycle engine.

In the figure, 2 indicates a crank of a two-cycle engine. Reference numeral 23 is a crankcase that supports the crank 2 on both sides via ball bearings and has a space in which the crank 2 can freely rotate. 54 is the crankcase 2
3 is a cover case which is combined with 3 to accommodate the recoil starter 30 therein. A pull rope reel shaft 54a sharing the center line with the crank shaft 2a is provided on the central side surface of the cover case 54. The pull rope reel 35 is rotatably fitted to the pull rope reel shaft 54a. The pull rope 29 is wound around the pull rope reel 35, and the pull rope 29 is coupled to the starter grip 11 installed outside the cover case 54. When the engine is started, the pull rope 29 is pulled by pulling the starter grip 11. Pulled and turned the pull rope reel 35,
When the starter grip 11 is released, the first spring 2
The pull rope 29 is rewound on the pull rope reel 35 by the restoring force of 7.

The outer end of the first mainspring 27 is bent and fixed to a projecting rod 54b provided in the cover case 54,
The inner end of the first mainspring 27 is bent and fixed to a protruding rod 35 a provided on the pull rope reel 35.
Further, the end portion of the pull rope 29 is stopped by forming a bump in a small chamber provided on the side wall of the groove bottom through a hole or a notch formed in the groove bottom of the pull rope reel 35.

A joint shaft 39 is concentrically attached to the pull rope reel shaft 54a by screwing it with a holding plate 41 interposed therebetween, and the joint shaft 39 and the intermediate shaft cylinder 4 are fixed to the joint shaft 39.
5 is rotatably fitted. As shown in the drawing, a protrusion 38a is provided inside the cylindrical portion 38c of the mainspring cover 38, and the protrusion 38a has a pulling force due to a frictional force with the restraining plate 41 when the pull rope reel 35 starts the engine. A ratchet pawl 42, which is adapted to project from the reel 35, is engaged to form a first ratchet mechanism for rotating the pull rope reel 35 and the mainspring cover 38 together. When the pull rope 29 is unwound, a frictional force in the opposite direction acts between the ratchet pawl 42 and the restraining plate 41, and the ratchet pawl 42 is pulled by the pull rope reel 35.
The ratchet pawl 42 on the inner side of is retracted to a position where it does not engage with the protrusion 38a of the mainspring cover 38.

The second mainspring 43 is attached to the mainspring cover 38.
Is stored. The outer end of the second mainspring 43 is bent and fixed to the notch 38b of the ring portion of the mainspring cover 38, and the inner end of the second mainspring 43 is bent and fixed to the notch 45a provided in the intermediate shaft cylinder 45. To be done. The second mainspring 43 is attached so as to be wound around the intermediate barrel 45 when the mainspring cover 38 is rotated in the engine starting direction.

An eccentric groove cam 45b is provided integrally with the intermediate shaft cylinder 45. The tension spring 2 is attached to the eccentric groove cam 45b.
The loop formed on the extension of the steel wire forming 6 is wound around the end of the tension spring 26 and the crankcase 23.
When the pull rope reel 35 rotates around the pin 28 sandwiched between the cover case 54 and the cover case 54 and the intermediate shaft cylinder 45 rotates, the pulling force against the pull rope reel 35 is increased by the eccentric position of the eccentric groove cam 45b. Changing, eccentric groove cam 4
Materials for reducing the frictional force are selected for the wire 5b and the wire of the tension spring 26, and positive and negative torques act on the intermediate shaft cylinder 45.

The eccentric groove cam 45b and the tension spring 2 described above.
The mechanism for relaxing the peak of the pulling force of the pull rope in the piston compression stroke according to No. 6 has the same operation mode as the mechanism of the recoil starter 10 of the first embodiment.
FIG. 8 can be used in common for the relationship between the pulling force and the rotation angle of the crank 2. That is, when the crank 2 is rotated by the pulling force of the pull rope 29, the pull rope pulling force FA in the piston compression stroke due to the change in the rotation angle of the crank 2 is indicated by a chain line.
The calculated value FB of the pulling force of the pull rope by the eccentric groove cam 45b and the tension spring 26 is shown by a broken line, and the relative angle position between the crank 2 and the protrusion 45c of the intermediate shaft cylinder 45 is appropriately determined and combined with the pull rope for the piston compression stroke. The attractive force is
As indicated by the solid line FC shown in FIG. 8, it is possible to obtain a smooth pulling force by suppressing the peak of pulling force FA of the pull rope 29 in the piston compression stroke. However, the pulling force FC shown in FIG. 8 is not added with the pulling force relaxing action of the second spring 43.

A ratchet support plate 15 is attached to the crankshaft 2a and tightened with a nut 19, and a ratchet pawl 16 is rotatably fitted to a pin 17 fixed to the ratchet support plate 15 and stopped by a snap ring. There is. The ratchet pawl 16 is pushed by a torsion spring 20 so that the tip of the pawl is directed toward the center line. The intermediate shaft cylinder 45 is provided with a protrusion 45c with which the ratchet pawl 16 engages, and the protrusion 45c and the ratchet pawl 16 form a second ratchet mechanism. When the engine crankshaft 2a is stopped or is rotating at low speed, the second ratchet mechanism is engaged, and when the crankshaft rotation is increased, the ratchet pawl 16 is attached to the inner circumference of the ratchet support plate 15 by centrifugal force, The ratchet mechanism 2 is disengaged. The second ratchet mechanism engages in the starting rotation direction from the intermediate shaft cylinder 45, but does not engage in rotation in the direction opposite to the start of the intermediate shaft cylinder 45.

The operation of the recoil starter 30 will be described. When the starter grip 11 is pulled, the ratchet pawl 42 attached to the pull rope reel 35 is projected in the outer peripheral direction and engages with the projection 38a of the mainspring cover 38, and the pull rope reel 35 is moved to the first position inside the mainspring cover 38. The intermediate shaft cylinder 45 is rotated via the second spring 43, and the protrusion 45c of the intermediate shaft cylinder 45 is engaged with the second ratchet mechanism formed by the ratchet pawl 16 to be coupled with the ratchet support plate 15. The crankshaft 2a (crank 2) is rotated. When the crank 2 starts to rotate and reaches the peak of the pulling force FC shown in FIG. 8, the intermediate shaft cylinder 45 engaged with the crank 2, the ratchet support plate 15, and the ratchet pawl 16 stops, and the second mainspring 43 Is rolled.

Further, the starter grip 11 is pulled (second
The mainspring 43 is wound), and when the peak of the attractive force FC is exceeded, the crank 2 rotates by itself due to the expansion of the compressed air-fuel mixture. Since the force for stopping the rotation of the intermediate shaft cylinder 45 disappears, the accumulated force of the wound second spiral spring 43 is released to accelerate the rotation of the intermediate shaft cylinder 45, thereby pushing the crank 2 rotating by itself. The crank 2 which has been pushed by the second mainspring 43 increases in rotational speed, and even if the next peak of the pulling force FC (piston compression stroke) is entered, the crank inertia overcomes the peak pressure of the compression stroke.

In addition to the pulling force of the starter grip 11,
The eccentric groove cam 4 with the inertial force and the pushing of the second mainspring 43.
5b, the auxiliary torque of the tension spring 26 causes the crank 2 to rotate at a high speed, and the engine starts. When the engine starts and the rotation speed of the crankshaft 2a exceeds the rotation speed of the intermediate shaft cylinder 45, the ratchet pawl 16 is disengaged from the projection 45c of the intermediate shaft cylinder 45, and when the rotation speed further increases, the ratchet pawl 16 causes centrifugal force. And ratchet support plate 15
Stick to the inner circumference of and completely disengage this ratchet.

[0025]

Third Embodiment A recoil starter 40 according to a third embodiment of the present invention is a recoil starter 1 according to the first embodiment.
0 acting force on the eccentric groove cam 25b
Instead of the circular wire attached to No. 6, the groove of the eccentric groove cam 25b is pushed by the roller from the opposite side so that the same action and function as the recoil starter 10 of the first embodiment can be obtained. The recoil starter 40 will be described below with reference to the drawings. 5 is a side sectional view of the recoil starter, and FIG. 6 is a sectional view taken along line CC of FIG. Note that this embodiment also exemplifies a case where it is applied to a small two-cycle engine.

As shown in FIGS. 5 and 6, the pushing force actuating mechanism for the eccentric groove cam 25b of the intermediate shaft cylinder 25 is provided with a rotatable actuating lever 47 pinned to a pin 49 installed in the cover case 34. A roller 46 is rotatably supported at the tip, and the operating lever 47 is given a pressing force by a tension spring 48 attached by applying tension between the operating lever 47 and a pin 51 provided on the cover case 34. With the roller 46,
The eccentric groove cam 25b is pushed. Operating lever 4
The crankcase for housing 7 and the tension spring 48 has a different part number 33 from the crankcase 23 of the recoil starter 10, and the cover case has a different part number 34 from the cover case 24 of the recoil starter 10.
Except for the above, the recoil starter 10 of the first embodiment is totally
Since the same parts are used, the description of the configuration will be omitted.

Further, the roller 4 with respect to the eccentric groove cam 25b
6 and the operation lever 47 and the tension spring 48 are almost the same as the actions of the eccentric groove cam 25b and the tension spring 26 in the recoil starter 10 of the first embodiment, and the combined force of the pull force of the pull rope 29. FC is the same as in FIG. The contact friction between the roller 46 of the recoil starter 40 of the third embodiment and the eccentric groove cam 25b depends on the contact friction of the eccentric groove cam 25 of the recoil starter 10 of the first embodiment.
Since the contact friction between b and the wire 26 of the tension spring 26 is much smaller, the pulling force of the pull rope 29 is closer to the characteristic curve shown in FIG.

Since the contact surface between the roller 46 and the eccentric groove cam 25b is small, the degree of freedom in the shape of the eccentric groove cam 25b is increased. Therefore, it is possible to select a cam profile that reduces the torque peak with respect to the crankshaft torque change due to the pressure applied to the piston during the compression stroke.

[0029]

[Fourth Embodiment] A recoil starter 50 according to a fourth embodiment of the present invention is a recoil starter 40 according to the third embodiment.
The intermediate shaft cylinder is divided into a pull rope reel side and an eccentric groove cam side, and the both are coupled via a shock-absorbing spring to transmit torque. Therefore, the function and operation of this recoil starter 50 are almost the same as those of the recoil starter 30 of the second embodiment. The recoil starter 50 will be described below with reference to the drawings. 7 is a side sectional view of the recoil starter 50, and FIG. 6 is a sectional view taken along the line CC of FIG. 7 (shared with FIG. 5). Note that this embodiment also exemplifies a case where it is applied to a small two-cycle engine.

As shown in the figure, the crankshaft 2 to which the pulling force is transmitted from the pull rope reel 35 of the recoil starter 50.
The structure of the drive part up to the ratchet support plate 15 attached to a is completely the same as the structure of the drive part of the recoil starter 30 of the second embodiment, and the description of the structure of this part is omitted. The pressing force operating mechanism of the intermediate shaft cylinder 45 against the eccentric groove cam 45b is the recoil starter 40 of the third embodiment.
Is the same as That is, the operating lever 4 that is rotatable by being pinned to the pin 49 installed in the cover case 44
A roller 46 is rotatably supported at the tip of 7, and an actuating lever 47 is given a rotating force by a tension spring 48 attached by applying tension to a pin 51 provided on the cover case 44, The roller 46 at the tip of the operating lever 47 pushes the eccentric groove cam 45b. Operating lever 47
The crankcase for housing the tension spring 48 and the tension spring 48 has a part number 33 different from that of the crankcase 23 of the recoil starter 10 of the first embodiment, and the cover case has a part number 44 different from that of the cover case 24 of the recoil starter 10.
Is taken.

Further, the roller 4 with respect to the eccentric groove cam 45b
The operation of the eccentric groove cam 2 in the recoil starter 40 of the third embodiment is performed by the operation of the 6, the operating lever 47, and the tension spring 48.
5b and the action of the tension spring 48 are the same, so the description thereof is omitted. The recoil starter 50 of the fourth embodiment
The contact friction between the roller 46 and the eccentric groove cam 45b is much smaller than the contact friction between the eccentric groove cam 25b of the recoil starter 10 of the first embodiment and the wire of the tension spring 26, as in the third embodiment. The pulling force of the pull rope 29 becomes closer to the characteristic curve shown in FIG.

As in the third embodiment, since the contact surface between the roller 46 and the eccentric groove cam 45b is small, the eccentric groove cam 45b is small.
The shape of can be arbitrarily selected. Therefore, it is possible to select the most convenient cam profile for reducing the torque peak with respect to the crankshaft torque change due to the pressure applied to the piston during the compression stroke.

As in the second embodiment, the second mainspring 43 is housed in the mainspring cover 38, and the pull rope 29
Is applied to the crankshaft 2a via the second spring 43.
Since the torque fluctuation transmitted from the driven side is alleviated in the second mainspring 43 in cooperation with the above, the starter grip 11 becomes smooth without a rugged feel, and the starting operation can be easily performed.

[0034]

In the recoil starter for starting the engine, (1) the pull rope reel and the crankshaft of the engine are engaged with each other by the second ratchet mechanism that can be disengaged by the centrifugal force, and the pull rope reel is connected to the pull rope reel. A wire is wound around an eccentric groove cam integrated with an intermediate shaft cylinder connected by a first ratchet, and the wire is pulled in one direction by a tension spring, and the wire and the tension spring cause the eccentric groove cam to change the fluctuation torque of the crank of the engine. Since the torque is applied in the direction of decreasing the peak, it is possible to reduce the peak torque during the compression process of the piston at the time of starting with the recoil starter, and prevent the decrease in the rotation speed before top dead center due to the cylinder pressure. The pulling force of the starter grip can be reduced, and the rotation speed of the crank can be increased to facilitate starting of the engine (claim 1).

(2) The intermediate shaft cylinder connected to the pull rope reel of the recoil starter of the above (1) by the first ratchet is divided into the intermediate shaft cylinder on the eccentric groove cam side and the mainspring cover on the first ratchet side. When the lever is connected with the second mainspring, the torque transmitted from the engine crank is not directly received by the pull rope, but is transmitted through the power storage spring built into the mainspring cover, so when starting with the recoil starter. The tension of the tensile force due to the in-cylinder pressure during the compression stroke is reduced to make it smoother, and if the peak of the compression stroke is overcome, it will be assisted by the mainspring force accumulated in the previous stage to accelerate. be able to. In this way, when the next engine cycle is approaching, the peak of the pulling force can be reduced, and the decrease in the rotation speed before top dead center due to the internal pressure of the engine cylinder can be prevented. It can be improved (Claim 2).

(3) Further, the wire is wound around the eccentric groove cam integrated with the intermediate shaft cylinder connected to the pull rope reel of the recoil starter of the above (1) by the first ratchet, and the wire is pulled by the tension spring in one direction. The one in which the eccentric groove cam is pushed by the roller from the opposite side instead of being pulled to has the same function and function as the recoil starter of (1), and at the same time the contact surface between the roller and the eccentric cam is small, so that the eccentric groove cam is small. The shape of the cam can be selected arbitrarily, and it becomes possible to select the most effective cam profile for reducing the torque peak with respect to the crankshaft torque change due to the pressure applied to the piston during the compression stroke. (Claim 3).

(4) The intermediate shaft cylinder connected to the pull rope reel of (2) above by the first ratchet is divided into the intermediate shaft cylinder on the eccentric groove cam side and the mainspring cover on the first ratchet side. Is connected by a second mainspring, and the eccentric groove cam is pushed by a roller as described in (3) above to reduce the torque of the crankshaft in the compression stroke. The configuration of (2) and (3) above Since both functions are provided together, both effects can be achieved at the same time (claim 3).

[Brief description of drawings]

FIG. 1 is a side sectional view of a recoil starter according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIGS. 1 and 4.

FIG. 3 is a sectional view taken along line BB of FIGS. 1 and 4.

FIG. 4 is a side sectional view of a recoil starter according to a second embodiment of the present invention.

FIG. 5 is a side sectional view of a recoil starter according to a third embodiment of the present invention.

6 is a cross-sectional view taken along line CC of FIGS. 5 and 7. FIG.

FIG. 7 is a side sectional view of a recoil starter according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing each pulling force with respect to a crank angle of the recoil starter shown in FIGS. 3 and 6;

[Explanation of symbols]

2 crank 2a crankshaft 11 starter grip 15 ratchet support plate 16, 42 ratchet pawl 20 torsion springs 24, 34, 44, 54 cover cases 24a, 34a, 44a, 54a pull rope reel shaft 35 pull rope reel 25b, 45b eccentric groove cam 25c, 45c Projection 26 Eccentric cam tension spring 27 First spring 29 Pull rope 31, 39 Joint shaft 38 Spring cover 41 Suppression plate 43 Second spring 25, 45 Intermediate shaft cylinder 46 Roller 47 Actuating lever 48 Tension spring

Claims (3)

[Claims] 1. A pull rope reel rotatably fitted to a shaft provided in a cover case of a recoil starter, and a pull rope wound around the pull rope reel and unwound by a restoring force of a first spring. In a recoil starter for starting an engine by pulling a pull rope and rotating a pull rope reel, a ratchet pawl that can be disengaged by a centrifugal force attached to a crankshaft of the engine, and the cover case. A joint shaft that extends and connects the shaft provided in the, a projection that engages with the ratchet pawl, and an eccentric groove cam. The joint shaft is rotatably fitted to the joint shaft. An intermediate shaft cylinder having a cylindrical portion with a large number of protrusions formed on the inside, and a pull rope pre-rotatably fitted to a shaft provided in a cover case. A holding plate sandwiched between the shaft provided in the cover case and the joint shaft, and attached to the side surface of the pull rope reel to spread outward due to frictional force with the holding plate when the pull rope reel is on the drive side. A reel ratchet having a ratchet pawl that engages with the inner protrusion of the intermediate shaft cylinder, a wire slidably wound around the eccentric groove cam, and a tension spring that pulls the wire in one direction. An engine recoil characterized in that the wire is attached to the cover case by determining the relative angular position with respect to the engine crank so that torque is applied to the eccentric groove cam by a tension spring in a direction to reduce the peak of fluctuation torque of the engine crank. Starter. 2. The recoil starter according to claim 1, wherein the intermediate shaft cylinder is provided with one projection that engages with a ratchet pawl and an eccentric groove cam, and the projection is rotatably fitted to the joint shaft. An eccentric cam shaft cylinder that does not have a formed cylindrical portion and a rotatably fitted fitting shaft, and a cylindrical portion where a large number of projections are formed inside the cylinder near the pull rope reel and the crank shaft The mainspring cover is divided into a mainspring cover and a mainspring cover, and the two are connected via a second mainspring to alleviate the unevenness of the torque at the time of starting and to combine them so that power can be stored. Characteristic engine recoil starter. 3. The recoil starter according to claim 1, further comprising a cam follower engaged with the eccentric groove cam, instead of the wire wound around the eccentric groove cam and the tension spring pulling the wire in one direction. , The eccentric groove cam is configured with a cam actuating lever attached to a cover case to determine a relative angular position with respect to the engine crank so as to apply a load via an elastic body in a direction to reduce the peak of fluctuation torque of the engine crank. A recoil starter for an engine that is characterized by: