JPH0619828Y2 - Engine starter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Use The present invention relates to an engine starter for starting a small engine using a motor with a motor, such as a portable working machine such as a brush cutter. Is.

(b) Prior Art and Problems to Be Solved Conventionally, in this kind of engine starting device, a starting device for starting an engine by a motor has a crankshaft 1 and a driven gear 3 as shown in FIG. The starter motor 9 is attached to the gear case 7 which is fixed to the crankcase 5 so as to cover the driven gear 3 and which is loosely engaged with the screw 13 provided on the outer circumference of the rotary shaft 11 of the starter motor 9. The gear 15 is provided so as to engage with the driven gear 3 in a disengageable manner, and when the starter motor 9 is started, the drive gear 15 tries to keep stationary due to inertial force with respect to the rotating shaft 11. Rotate relative to each other, jump out in the axial direction by the screw 13, mesh with the driven gear 3, rotate the crankshaft 1, and start the engine. When the engine starts to rotate, the driven gear 3 has a higher circumferential speed, so that the drive gear 15 rotates in the opposite direction relative to the rotating shaft 11, and the screw 1
By means of 3, the driven gear 3 is returned in the direction opposite to the axial direction.
To leave. In this structure, the pop-out mechanism for moving the drive gear 15 in the axial direction is complicated, and the gear and the like are easily damaged by the impact when popping out. Since the crankshaft and the bearing need to be provided with a large strength by being fixed to and constantly rotating, and the driven gear 3 having a large inertial force is suddenly started by the protrusion of the driving gear 15, There was a defect that the rotating shaft of the starting motor, gears, etc. were severely damaged.

(c) Means and Actions for Solving the Problem In the present invention, washers 47 and 49 are attached to one end of the crankshaft 35 of the engine 21 with a space, and the non-return type clutch 53 is provided between the washers 47 and 49. The driven gear 51 is axially supported with a clearance in the axial direction via a shaft, and a starter motor 71 is attached to a gear case 69 that covers the driven gear 51 and is fixed to the crankcase 31. A drive gear 75 that is constantly meshed with the driven gear 51 on the shaft 73.
The clutch 53 includes a cylindrical case 56 having a plurality of projecting pieces 61 and an inclined surface 63 protruding at predetermined intervals on the inner diameter surface, an inclined surface 63 in the cylindrical case and an outer peripheral surface of the crankshaft 35. A plurality of rollers 57 held between
And rollers 65, 65 that are fitted outside the axial ends of the roller 57 and between the inner surface of the cylindrical case and the outer peripheral surface of the crankshaft 35 to form a bearing.
According to the present invention, since the rotation of the driven gear and the like gradually increases with the rotation of the starting motor at the time of starting, there is no impact and wear of the gear, bearing and the like is small. Further, after the start, the rotation of the crankshaft becomes faster than the rotation of the driven gear and relatively rotates in the opposite directions, so that the non-return type clutch is unlocked. If the starting motor is stopped after the engine is started, the driven gear stops and only the crankshaft rotates, so that the driven gear having a large inertial force does not rotate at high speed.

(d) Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a brush cutter equipped with the device of the present invention, in which a bearing body 19 for rotatably supporting a rotary blade 17 and an engine 21 are connected by a tubular connecting rod 23, and the inside of the transmission shaft ( (Not shown) penetrates. A grip 25 and a handle 27 are fixed to the connecting rod 23, and a grip 29 is provided at an end of the handle 27. The engine 21 is configured as follows. That is, in FIGS. 2 and 3, a crankshaft 35 is pivotally supported by a crankcase 31 via a bearing 33, and a crank arm 37 of the crankshaft 35 is connected by a crankpin 39 to a connecting rod 41. One end of is pivotally attached. Connecttain Grod 4
The other end of 1 is connected to a piston (not shown) which is reciprocally slidably fitted in a cylinder 43 fixed to the upper portion of the crankcase 31. A fuel tank 45 is fixed to the lower portion of the crankcase 31. At one end of the crank shaft 35, a driven gear 51, which is held between the washers 47 and 49 with a clearance, is pivotally supported by a non-return type clutch 53, and a nut 55 serves as a positioning member. It has been stopped.
In the non-return type clutch 53, a plurality of rollers 57 are held at predetermined intervals by holding rings 59, 59 in a cylindrical case 56 press-fitted into the inner diameter hole of the driven gear 51, and the inner diameter surface of the cylindrical case 56 is retained. The inclined surface 63 on one side of the protruding piece 61 protruding in the direction
When the crankshaft 35 relatively rotates in the direction of, the roller 57 rides on the inclined surface 63 and is pushed between the crankshaft 35 and the cylindrical case 56 to lock the relative motion.
When it rotates in the opposite direction, the roller 57 separates from the inclined surface 63 and rotates freely. Roller 5
Bearing rollers 65, 65 are fitted to the circular inner diameter surface of the cylindrical case 56 to support the crankshaft 35 at the outer sides of both ends of the shaft 7. A gear case 69 that covers the driven gear 51 is fixed to the flange portion 67 of the crankcase 31,
The rotating shaft 7 of the starting motor 71 fixed to the gear case 69.
A drive gear 75 is fixed to the drive shaft 3 and is always meshed with the driven gear 51.

In the above configuration, when the starter motor 71 is driven, the driven gear 51 rotates via the drive gear 75, and the cylindrical case 56 of the clutch 53 rotates in the direction of arrow A in FIG. The roller 57 is in contact with the outer periphery of the crankshaft 35 that rotates in the opposite direction, rolls along the inclined surface 63, and is pressed and held between the inclined surface 63 and the crankshaft 35. The engine 29 starts by rotating together with the driven gear 51 via 57. When the engine 29 is started, the rotation speed of the crankshaft 35 changes to the driven gear 51.
And the cylindrical case 56 rotates in the direction opposite to the arrow A relative to the crankshaft 35, the roller 57 is separated from the inclined surface 63 and becomes free, and the starting motor 71 is stopped. By doing so, the driven gear 51 stops and only the crankshaft 35 rotates.

Moreover, since the driven gear 51 is axially supported by the crankshaft 35 via the non-return type clutch 53 with a bearing,
A nut 55 with play between the washers 47 and 49 at both ends.
It is possible to mount with a compact structure to cope with the movement in the thrust direction.

(e) Benefits of the device The device of the present invention has the structure as described in the claims, so that the structure is simple and can be manufactured at low cost. In addition, the damage of the bearing of the starting motor is small, and the driven gear having a large inertial force stops after the starting, so that the damage of the crankshaft, the bearing, etc. is reduced.

The non-return type clutch in the present invention is not limited to the method using the roller of the above-mentioned embodiment,
By means of other means such as a ratchet, the driven gear and the crankshaft can freely rotate in one direction relative to each other to interrupt the transmission, and lock in the opposite direction to each other to rotate as one body. It may be configured to.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of a brush cutter equipped with the device of the present invention, FIG. 2 is a side sectional view of one embodiment of the present invention, FIG. 3 is a front sectional view of essential parts, and FIG. 4 is a conventional example. FIG. 21 ... Engine 31 ... Crank Case 35 ... Crank Shaft 51 ... Driven Gear 53 ... Clutch 69 ... Gear Case 71 ... Start Motor 73 ... Rotation Shaft 75 ... Drive Gear

Claims (1)

[Scope of utility model registration request] 1. A washer 47, 49 is attached to one end of a crankshaft 35 of an engine 21 with a space therebetween, and a driven gear 51 is axially mounted between the washer 47, 49 via a non-return type clutch 53. The driven gear 51 is axially supported with a play.
A gear case 69 that covers and is fixed to the crank case 31
A starter motor 71 is mounted on the drive gear 7, and a rotating shaft 73 of the starter motor 71 is constantly engaged with the driven gear 51.
5, the clutch 53 includes a cylindrical case 56 having a plurality of projecting pieces 61 and an inclined surface 63 protruding on the inner diameter surface at predetermined intervals, an inclined surface 63 in the cylindrical case and an outer peripheral surface of the crankshaft 35. A plurality of rollers 57 held between
And the rollers 65, 65 that are fitted to the outside of both ends of the roller 57 in the axial direction and between the inner diameter surface of the cylindrical case and the outer peripheral surface of the crankshaft 35 to form bearings. Starter.