JPH0461192B2 - - Google Patents

Abstract

PURPOSE:To aim at improvement in durability in reducing a sliding speed by half at both inner and outer taper surface parts when a catching phenomenon occurs, by installing a taper cylindrical collar side by side between taper surfaces pressing a reduction gear with each other free of slide motion. CONSTITUTION:With starter motor operation, to be decelerated from a pinion gear and transmitted to a first gear 20 is decelerated and transmitted to a shaft 19 from the first gear 20 within the torque capacity range of a torque limiter 23 and furthermore to a crankshaft via a second gear 18. And, immediately after engine starting, a catching phenomenon, where the crankshaft is reversed, is caused and thereby excessive load is imposed on these gears 18, 20 or the like, but the turning torque of the first gear 20 becomes larger than capacity of the torque limiter 23, so that the first gear 20 slips to the shaft 19 whereby excessive torque is prevented from occurring. At this time, an interval between taper surfaces, where a flange 26 of the shaft 19 and the first gear 20 both come into contact with pressure, is relatively slidden with each other via a taper cylindrical collar 30, thus a sliding speed to this collar 30 is reduced by almost half. Doing like this, durability in a starter is improved.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention connects a freewheel gear connected to the crankshaft of an internal combustion engine via a one-way clutch and an output pinion gear of a starter motor via a reduction gear. The present invention relates to a starting device for an internal combustion engine in which a torque limiter is formed by dividing a reduction gear into an outer ring gear and an inner hub shaft separated by a tapered surface that presses against each other.

(Prior Art) The present applicant has made various proposals regarding torque limiters that can be adopted in starter motor type starting devices for internal combustion engines (for example, JP-A-61
−282644, JP-A-61-290259, U.S.-A. 62-
106028, Jitsukai 62-2839). These torque limiters are tapered surface type torque limiters formed inside some reduction gears in a gear transmission mechanism, and one reduction gear is connected to an outer ring gear and an inner hub shaft separated by a tapered surface that presses against each other. It has a divided structure. . However, if such a torque limiter is placed in an atmosphere of atomized lubricating oil (mist) in the gear case between the crankshaft and the starter motor, it may cause problems when the crankshaft suddenly receives an impact in the opposite direction when starting the engine. , Accelerated and impactful sliding occurs on the inner and outer tapered surfaces forming the torque limiter, which may cause abnormal wear or, in extreme cases, seizure.

(Purpose of the Invention) The present invention relates to the relative sliding speed (peripheral speed) between the inner and outer tapered surfaces forming the torque limiter.
The purpose is to reduce the amount of wear by half and avoid the abnormal wear and seizure phenomenon.

(Structure of the Invention) The present invention provides a one-way clutch 1 on the crankshaft 2.
2 and the output pinion gear 22 of the starter motor 21,
Connect via the reduction gear, and connect the reduction gear to the disc spring 29.
The tapered surfaces 20 are biased in the direction of pressure contact with each other by
A, 26a are separated into an outer ring gear 20 and an inner hub shaft 19, and a tapered cylindrical collar 30 is slidably inserted between opposing tapered surfaces to form a torque limiter. 19 is placed in a mist lubricating oil atmosphere, and a plurality of mist-shaped recesses are alternately recessed into the collar 30 from both edges of the small diameter side and the large diameter side so as to overlap by a certain section L1 in the middle part of the axial width. Lubricating oil introduction notches 32, 33
This starting device for an internal combustion engine is characterized in that the inner and outer tapered surfaces 20a and 26a of the collar 30 facing the collar 30 are formed of different metals.

Due to the action of the tapered cylindrical collar that is slidably placed between the inner and outer tapered surfaces, the sum of the relative sliding speed between the outer tapered surface and the collar and the relative sliding speed between the collar and the inner tapered surface is is the relative sliding speed between the inner and outer tapered surfaces, so the relative speed (circumferential speed) at each sliding portion is approximately halved.

(Example) Fig. 2 shows an example in which the present invention is applied to a starting device for a two-wheeled motor vehicle. extends to the crankshaft 2
A generator hub 5 is fixed to the tip of the generator.
A flywheel 6 is fixed to the hub 5, and a magnet 7 is fixed to the flywheel 6.
A coil 8 facing the magnet 7 is fixed to the crankcase cover 3.

A freewheel gear 10 is arranged next to the hub 5, and the freewheel gear 10 is rotatably supported on the crankshaft 2 via a bearing metal 11, and is connected to the hub 5 via a sprag type one-way clutch 12. are doing. The outer 13 of the one-way clutch 12 is connected to the hub 5 by bolts 15.
A cam such as a sprag is disposed between the inner 16 and outer 13 that are fixed to the freewheel gear 10 and are integral with the freewheel gear 10, and transfers only the rotational force that rotates the crankshaft 2 in the forward direction (arrow R) from the freewheel gear 10 to the crankshaft 2. is configured to communicate. Therefore, the one-way clutch 12 rotates idly after starting, but when the crankshaft 2 receives an impact torque in the reverse R direction due to the locking phenomenon at the time of starting, the one-way clutch 12 is locked and the reverse rotation is caused by the crankshaft 2.
The signal is transmitted to the freewheel gear 10 from there.

The freewheel gear 10 includes a small reduction gear 17a, a large reduction gear 17b, a second starting gear 18, a starting shaft 19 (hub shaft), and a ring-shaped first starting gear 2.
The output pinion gear 22 of the starter motor 21 is interlocked with the output pinion gear 22 of the starter motor 21 via a ring gear. axis 1
A torque limiter 23 is configured between the first gear 9 and the ring-shaped first gear 20. A starting shaft 19 is rotatably supported by the crankcase cover 3 and gear case 25 via a bearing metal. The outer diameter of the first gear 20 is larger than the outer diameter of the second gear 18,
The speed is also reduced by both first and second gears 20 and 18. Both reduction gears 17a, 17b
are integrally formed with each other and rotatably supported by a support shaft 27, which is supported by the crankcase cover 3 and gear case 25. The inside of the crankcase cover 3 is filled with mist of lubricating oil generated by the rotation of the crankshaft 2. The gear transmission mechanism of the starter system from the pinion gear 22 of the starter motor 21 to the freewheel gear 10 of the crankshaft 2 is of a constant mesh type. That is, unlike the conventional motor, the pinion gear of the starter motor does not protrude and engage with the gear only at the time of starting, but as shown in the figure, the pinion gear 22 does not move in the axial direction and always engages with the first gear 20. Further, the second gear 18 is always meshed with the large reduction gear 17b, and the small reduction gear 17a is connected to the freewheel gear 1.
It is always engaged with 0. The reduction ratio of the starter system gear transmission mechanism is, for example, 1/30. That is, the rotational speed of the starter motor 21 is reduced to 1/30 and transmitted to the crankshaft 2.

In FIG. 1 showing an enlarged view of the torque limiter 23, an outward flange 26 is integrally formed on the shaft 19, and a male thread 19a is formed next to the A side (crankcase cover side) of the flange 26. There is. The outer peripheral surface of the flange 26 is formed as a tapered surface 26a that becomes smaller in diameter as it goes toward the A side, and the inner peripheral surface of the ring-shaped first gear 20 is formed as a tapered surface 20a that becomes smaller in diameter as it goes toward the A side. A tapered cylindrical collar 30 is slidably interposed between 20a and 26a.
As shown in FIGS. 3 and 4, the collar 30 includes an inward flange 31 at the small diameter end, and a plurality of mist introduction notches 32 alternately from both edges of the small diameter side and the large diameter side.
33 is formed, and the depth of both notches 32 and 33 is determined so that they overlap by a section L1 (for example, 3 mm) at the middle part of the width of the collar 30. The tapered surfaces 30a and 30b on the inner and outer peripheries of the collar 30 are
They each have the same taper angle θ (FIG. 1) as the corresponding tapered surfaces 20a and 26a, and are made of a steel material (for example, SK5) that is harder than the shaft 19 and the first gear 20 (steel material).

Therefore, the ring-shaped first gear 20 is tapered fitted to the flange 26 via the collar 30 made of a different metal. Tapered surfaces 20a, 26a, 30a,
The taper angles θ of the joints 30b are the same, and are formed at an angle (6 degrees in the illustrated embodiment) to prevent the tapered surface of the joint portion from digging into the tapered surface of the mating portion. The second gear 18 is screwed into a male screw 19a, and is integrally provided with a boss portion 18a on the B side, and a metal shim 28 and a disc spring 29 are fitted to the outer periphery of the boss portion 18a in order from the A side. The B-side end surface of the boss portion 18a is in contact with the side surface of the flange 26. The disc spring 29 has a shim 28 at its inner peripheral edge.
The outer peripheral end of the disc spring 29 is in pressure contact with the side surface of the first gear 20 on the A side. That is, the disc spring 29 is connected to the first gear 20 and the second gear 1.
8, thereby causing the first gear 20 to
side, applying pressure contact force between the tapered surfaces 20a, 30b and between the tapered surfaces 26a, 30a.

By changing the thickness of the shim 28, the spring 29
The maximum torque capacity is adjusted by adjusting the biasing force (setting pressure) of or by changing the taper angle θ of the tapered surfaces 20a, 26a, 30a, and 30b.

(Function) When the second gear 18 (Fig. 1) is tightened and the axial force of the spring 29 is applied to the first gear 20,
The surface pressure in the direction perpendicular to the tapered surface 26a is much larger than that in the axial direction. Therefore, a large maximum torque capacity can be set with a small contact area. Before assembly, each tapered surface is coated with, for example, molycoat grease.

When the starter motor 21 shown in FIG. 2 is operated when starting the engine, the rotational torque that is reduced from the pinion gear 22 and transmitted to the first gear 20 is transferred from the first gear 20 to the shaft within the torque capacity range of the torque limiter 23. 19, and further transmitted to the second
Gear 18, reduction gears 17b, 17a, freewheel gear 10, one-way clutch 12, and hub 5
The signal is decelerated and transmitted to the crankshaft 2 via.

Immediately after starting, a reversal phenomenon of the crankshaft 2 (the so-called butt-in phenomenon) occurs, causing the gears 10, 17a,
An excessive load may be applied to 17b, 18, and 20, but in that case, the rotational torque of the first gear 20 becomes larger than the capacity of the torque limiter 23, so the first gear 20 slips with respect to the shaft 19, causing the first gear 20 to slip. This prevents excessive torque from being applied to the 1st gear 20.
Prevent damage to the gear 20. At this time, relative sliding occurs at the joint portions of the inner and outer tapered surfaces 20a and 26a.

Furthermore, if a reverse rotation occurs in the crankshaft 2 while the starter motor 21 is stopped, the reverse rotation of the crankshaft 2 is transmitted to the starting shaft 19 via the freewheel gear 10 etc., and then the first gear 20
attempts to reversely rotate the pinion gear 22 via the Since the torque at the beginning of reverse rotation is very large, by providing a tapered surface type torque limiter, the shaft 19 slips with respect to the first gear 20 at the beginning of reverse rotation, and then the tapered surfaces 20a, 3
The friction force between the shaft 19 and the tapered surfaces 26a and 30a applies a brake to the reverse rotation of the shaft 19, thereby reducing the rotational speed of the shaft 19, the second gear 18, etc.

Since the shaft 19 and the first gear 20 are completely connected after the shaft 19 reaches a low speed and the torque becomes small, even if the pinion gear 22 rotates in the opposite direction, the speed will be slow and the bearings in the starter motor 21 will be damaged. There is no need to worry about heat damage.

By the way, if a reverse rotation phenomenon occurs in a starter device that is not equipped with a torque limiter 23, the starter motor will rapidly rotate in the opposite direction, and the number of reverse rotations will increase, which may damage the starter motor's bearings, etc. . On the other hand, if a tapered surface type torque limiter that also acts as a brake mechanism is provided, it is possible to eliminate sudden reverse rotation by acting as a torque limiter, and the reverse rotation speed can be kept small by the braking action. Prevent damage to starter motor bearings, etc. Moreover, when the collar 30 of the present invention is adopted, the relative sliding speed at the tapered surface portion is divided into two parts, the inner and outer parts, and the relative speed at each sliding part is significantly reduced.

(Effects of the Invention) As explained above, according to the present invention, color 30
As a result, the sliding speed on the inner and outer tapered surfaces when the phenomenon occurs is approximately halved compared to conventional ones, reliably preventing abnormal wear and seizure phenomena, and improving the durability of the starting device. .

Furthermore, in the present invention, a plurality of atomized lubricating oil (mists) are introduced into the collar 30 from both side edges of the small diameter side and the large diameter side, which are recessed alternately so as to overlap by a certain section L1 in the middle part of the axial width. Since the notches 32 and 33 are provided, the surrounding mist smoothly enters the notches 32 and 33, and there is no need to provide a forced lubrication mechanism.
Lubrication of the tapered surface is improved all at once. That is, the mist enters deep into the notches 32 and 33, and reaches the section L1.
Since mist is supplied from both notches 32 and 33 over the entire circumference within the width of , an oil film is ensured over the entire tapered sliding surface. Moreover, the flexibility of the collar 30 is increased by the overlapped notches 32 and 33 in the section L1, and it conforms to the tapered surface of the other party, making the surface pressure uniform in each part and reliably preventing local wear. Benefits arise. In addition, since the inner and outer tapered surfaces of the collar 30 that are opposed to the collar 30 are formed of different metals, the compatibility is poorer than when pressure-welding similar metals, and from this perspective, the seizure resistance is also poor. will improve.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of the main parts, Figure 2 is a vertical cross-sectional view when the present invention is applied to a motorcycle, and Figure 3 is an enlarged vertical cross-sectional view of the collar alone in Figures 1 and 2. 4 is a partial front view taken in the direction of the arrow in FIG. 3. 2...Crankshaft, 10...Freewheel gear, 1
2...One-way clutch, 19...Starting shaft (hub shaft), 20...First gear for starting (ring gear), 20
a, 26a... Tapered surface, 21... Starter motor, 22... Output pinion gear, 30... Collar.

Claims (1)

[Claims] 1. The freewheel gear 10 fitted to the crankshaft 2 via the one-way clutch 12 and the output pinion gear 22 of the starter motor 21 are connected via a reduction gear, and the reduction gears are pressed against each other by a disc spring 29. The pressed tapered surfaces 20a, 2
The ring gear 20 and the hub shaft 19 are divided into an outer ring gear 20 and an inner hub shaft 19 with 6a in between, and a tapered cylindrical collar 30 is slidably inserted between the opposing tapered surfaces to form a torque limiter.
are arranged in a mist lubricating oil atmosphere, and a plurality of mist lubricant oils are recessed alternately into the collar 30 from both side edges of the small diameter side and the large diameter side so as to overlap by a certain section L1 in the middle part of the axial width. Provide oil introduction notches 32 and 33,
A starting device for an internal combustion engine, characterized in that the inner and outer tapered surfaces 20a and 26a of the collar 30 and the opposing inner and outer tapered surfaces are formed of different metals.