JPH0697023B2 - Starter for small engine - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a starter for a small engine, and more particularly to a starter for a small engine using a starter motor.

[Prior art]

A small engine is used as a power source for a brush cutter, a power sprayer, and the like.This small engine requires external power at startup, so it has a recoil starter. It is necessary to rotate the crankshaft with an arm force that exceeds the compression stroke of the engine, which is one of the troublesome works for the elderly and women who have poor arm strength. In order to reduce the burden of such start-up work, a starter torque is provided with a starter motor by using a recoil starter,
There are those configured to start together with the starting torque of the starter motor, and those configured to start with the starting torque of the starter motor alone.

[Problems to be Solved by the Invention]

The starter using the starter motor as described above has a pinion attached to the output shaft of the starter motor that is constantly meshed with a ring gear provided on the crankshaft of the engine. A one-way clutch is provided between the crankshaft and the output shaft of the starter motor so that the starter motor will not be driven in reverse via the pinion with the output torque of. Since this one-way clutch has a function of transmitting the rotational torque, it is structurally complicated and requires a considerable amount of strength to transmit the rotational torque. , It will not be suitable for a small engine installed in a power sprayer. Therefore, in order to change the ring gear and the pinion from the constant mesh type to the constant mesh type only at the time of starting, the cell motor unit having the pinion is rocked with respect to the ring gear so that the pinion meshes with the ring gear. The applicant has previously proposed. However, the on / off operation of the starter motor, in other words,
The engagement between the pinion and the ring gear, or the disengagement work is done artificially.
Since the power is also turned off artificially, there is a case where the power switch is left on even though the engine has been started. Despite the fact that the start-up was started, there was a case where the starter motor was rotated at an increased speed via the pinion and was damaged while being in a state of meshing with the pinion and the ring gear. In this invention, as a starting operation, the operation arm and the starter motor unit are once pushed to engage the pinion and the ring gear, and then the pressing operation on the operation arm is released to turn on the starter circuit of the starter motor to rotate the starter motor. It is something to try.

[Means for Solving the Problems]

Therefore, the present invention is provided with a ring gear connected to a crankshaft and a cell motor unit having an output shaft having a pinion capable of meshing with the ring gear, and the cell motor unit and an operating arm for swinging the cell motor unit are provided in an engine body. It is pivotally attached and can swing within a certain range in a plane orthogonal to the axis of the crankshaft, and the starter motor unit moves the pinion and ring gear meshing position and inflection point beyond the inflection point by the toggle spring. It has a position holding mechanism that can hold it in the disengagement position where it does not exceed, and the operation arm always has a tendency to return to a predetermined position on the side of the disengagement position where the cell motor unit does not exceed the inflection point by the tension spring. Then, a pair of terminal terminals are provided on the peripheral surface of the holder of the cell motor unit, and the cell motor unit is placed at the meshing position of the pinion and ring gear. A switch mechanism is configured by providing a conductor having a length capable of simultaneously contacting the pair of terminals on the operating arm for insertion, and after pushing the cell motor unit into the meshing position of the pinion and the ring gear with the operating arm, the operating arm When only the chisel is returned to the predetermined position by the tension spring, the switch mechanism is turned on, the starter motor is driven, the ring gear and the crank shaft are rotated through the pinion, and the engine is started.
The pinion receives the drive reaction force of the ring gear that accompanies the start of the engine, moves the cell motor unit to the disengaged position and holds it, and the switch mechanism is turned off to shut off the cell motor unit power. It is characterized by.

[Work]

With the above-described structure, the starting device for the small engine of this application is such that, when the engine is started, the operator simply pushes the operating arm with his finger to release the pushing finger, and then the switch mechanism of the starter motor is automatically changed. When the engine is turned on and the engine is started, the ring gear receives the driving reaction force to automatically disengage from the pinion, and at the same time, the switch mechanism is turned off.

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the figure, reference numeral 10 indicates a casing forming an engine body, a part of the casing 10 is shown, and a crank shaft 11 which is an output shaft of the engine is supported by a bearing 12 in the casing 10. A cooling fan 13 is attached to the shaft end of the. The cooling fan 13 is provided with a clutch shoe mounting seat 14A that forms a centrifugal clutch. The clutch shoe 14 is mounted on this, and a clutch drum 15 is arranged along the outer periphery of its rotation region.
An output shaft 15A having a spline is formed in the center of the clutch and these are housed in a clutch housing 16. The cooling fan 13 has a blower blade 13A and a ring gear 17 on the outer circumference of the maximum diameter portion of the cooling fan 13. Then, in the casing 10 described above, the starter motor unit 20
Is pivoted on the lower portion of the clutch housing 16 by a pivot shaft 21 so as to swing in a plane orthogonal to the axial center of the crankshaft 11, and the swinging range of the starter motor unit 20 is set on the lower portion of the clutch housing 16. An arc-shaped swing limiting frame 18 for limiting is formed. A stopper 22 protruding from the outer periphery of the holder of the starter motor unit 20 is fitted in the swing limit frame 18, and the swing limit frame 18
The starter motor unit 20 can be swung between the end portions 18A and 18B of 18. This cell motor unit 20 has a cylinder type holder 23, and a flange 24 is formed in the lower portion thereof, and the pivot shaft 21 penetrates the flange 24 and the threaded portion 21A formed at its end is screwed into the clutch housing 16. Therefore, it is swingably supported. Further, a spring hook 23A is provided on the outer peripheral portion of the holder 23 so as to project from the holder 23 and the clutch housing 16A.
The end portions 25A and 25B of the toggle spring 25 are hooked between the spring hook 16A and the spring hook 16A protruding from the outer periphery of the pivot shaft 21.
And an inflection point is formed on a line P-P connecting the center of the spring hook 16A with the spring hook 16A. Therefore, the position holding mechanism is formed so as to hold the cell motor unit 20 at the positions of both ends of the swing region by rotating the cell motor unit 20 beyond the inflection point. An operating arm 26 for starting the engine is pivotally attached to a pivot 21 which is a swinging fulcrum of the starter motor unit 20,
A tension spring 26B provided between the other end 26A of the operation arm 26 on the side of the pivot 21 and the clutch housing 16 imparts habit in a direction away from the surface of the holder 23 of the starter motor unit 20. Inside the operation arm 26, in other words, on the surface facing the holder 23, a protrusion 26E capable of contacting the curved surface portion of the holder 23 is formed, and on the front side, a push seat 26F for hanging a finger is formed. . Further, at the upper end of the side portion of the operation arm 26, an extension arm 26 is fitted along the curved surface of the holder 23 and along the upper surface thereof.
X is integrally formed, and a conductor forming a switch mechanism described later is provided on the inner peripheral side of the distal end portion of the extension arm 26X. A cell motor 27 is housed in the holder 23, and is fixed to the holder 23 with screws 27A. A pinion 28 that can mesh with the ring gear 17 is fixed to the output shaft 27B of the cell motor 27. This pinion
Reference numeral 28 maintains a positional relationship in which one end of the swing region of the starter motor unit 20 is engaged with the ring gear 17 and the other end is disengaged. The starter motor 27 receives power from a portable battery which is an external power source, and has a pin jack 29 which is a connection terminal with the power source. In addition, the stopper 22 of the starter motor unit 20 is the swing limit frame.
Terminal terminals 31, 32 are attached to the outer peripheral portion of the holder 23 in a state of hitting the end portion 18B of 18 in a crimped state with respect to the pin protrusions 23X, 23Y formed on the holder 23. , 32 is a holder facing the extension arm 26X
Protruding on the surface of 23. These terminal terminals 31,3
An elastic conductor such as a phosphor bronze piece for conducting between the two 33
However, the switch mechanism 30 is configured by being attached to the inner circumference of the extension arm 26X. This conductor 33 is a terminal terminal
The power supply circuit of the starter motor 27 can be closed by making the terminal terminals 31 and 32 conductive so that the terminals 31 and 32 can be simultaneously contacted with the terminals 31 and 32. The output shaft 15A protruding into the clutch housing 16 is spline-coupled with the transmission shaft of the brush cutter, though not shown. Next, the starting operation by the small engine starting device according to the present invention will be described. First, cell motor unit 20
After inserting the pin plug extended from the external power source into the pin jack 29 of No. 1 and connecting to the power source, the operation arm 26 constituting the starter motor unit 20 is pressed against the tension spring 26B with the thumb or the like, and the protrusion 26E is When hitting the holder 23, the cell motor unit 20 is rotated around the pivot shaft 21 against the elasticity of the toggle spring 25, and when the inflection point is exceeded, the toggle motor 25 causes the cell motor unit 20 to project from the holder 23. A certain stopper 22 is moved from the end portion 18A of the swing limiting frame 18 until it comes into contact with the end portion 18B. In this state, the pinion 28 meshes with the ring gear 17, but the conductor 33 of the extension arm 26X of the operation arm 26 is pushed in while maintaining the relative relationship position exceeding one of the terminal terminals 31, 32, and the terminal terminal The state in which only the terminal terminal 31 is kept in contact with 32 but not in contact (FIG. 11) is maintained, the power supply circuit of the starter motor 27 remains open, and the starter motor 27 does not rotate. From this state, when the pressing of the finger against the operation arm 26 is released, only the operation arm 26 has the swinging end portion 26A centered on the pivot 21 pulled by the tension spring 26B. As in the state shown in Fig. 9, move to the stopper 16X and return to the position before pushing. In this state, the conductor 33 comes into contact with both terminal terminals 31 and 32 and the cell motor 27
The power supply circuit is closed and the starter motor 27 rotates. In other words, the pinion 28 fixed to the output shaft 27B of the starter motor 27 of the starter motor unit 20 is located at the meshing end portion of the swing region and meshes with the ring gear 17, so that the crankshaft 11 is inserted through the ring gear 17. Is rotated to start the engine (ninth). Then, when the engine is started, the driving reaction force of the ring gear 17 causes the starter motor unit 20 to swing beyond the inflection point against the elasticity of the toggle spring 25, and the end portion 18A of the swing limit frame 18 is stopped. Return until 22 is limited, pinion 2
The meshing relationship between 8 and the ring gear 17 is released. Also,
The conductor 33 is separated from both terminal terminals 31, 32, and the starter motor 2
The power of 7 is turned off. At this time, the holder 23 of the starter motor 27 is in contact with the protrusion 26E of the operation arm 26 (the tenth position).
Figure).

【The invention's effect】

As is clear from the above description, the starter for a small engine according to the present invention is capable of swinging a starter motor unit having a pinion capable of meshing with a ring gear capable of driving a crankshaft of an engine. The pinion and the ring gear are engaged with each other at one end of the swing region and the other end is disengaged so that the swing position of the cell motor unit is held by a position holding mechanism such as a toggle spring. The cell motor unit is equipped with an operation arm that automatically returns independently from the meshing end of the pinion to the meshing release end in cooperation with the swinging motion of the cell motor unit, and a switch mechanism is provided between the operation arm and the holder. The operation arm and holder swing toward the meshing end side of the pinion, and when the operated hand is released, only the operation arm returns to the meshing release end side. Switch mechanism is turned on in the state,
Since the power circuit of the starter motor is configured to be closed, when the engine is started, the operator pushes the pusher seat of the operation arm with his finger and keeps pushing it in until the stopper of the holder contacts the end of the swing limit frame. Since the starter motor does not rotate, the operator pushes the starter motor unit and the engine is running, but the user continues to press the starter motor unit, which damages the pinion and consumes the battery unnecessarily. Without simply pushing the operating arm and releasing the pushing of the finger, the switch mechanism of the starter motor is automatically turned on, and when the engine is started, the reaction reaction force of the ring gear is received and the pinion is automatically activated. Is disengaged and the switch mechanism is turned off at the same time, so that the usability of the operator can be greatly improved.

[Brief description of drawings]

The attached drawings show an embodiment of the present invention. Fig. 1 is a vertical sectional view of a starter for a small engine, Fig. 2 is a side view of a starter motor unit, and Fig. 3 is a sectional view taken along line III-III in Fig. 1. Fig. 4, Fig. 4 is a sectional view taken along the line IV-IV in Fig. 1, Fig. 5 is a sectional view taken along the line VV in Fig. 1, and Fig. 6 is a sectional view taken along the line VI-VI in Fig. 2. FIG. 7 is a sectional view taken along the line VII-VII in FIG.
8 is a sectional view taken along the line VIII-VIII of FIG. 7, FIG. 9 is an explanatory view of a state in which the ring gear and the pinion mesh with each other and the switch mechanism is on, and FIG. 10 shows that the starter motor unit is disengaged, FIG. 11 is an explanatory diagram of a state in which the switch mechanism is off, and FIG. 11 is an explanatory diagram of a state in which the pinion is engaged and the operation arm is pushed in. 10 …… Casing 11 …… Crankshaft, 12 …… Bearing, 13 …… Cooling fan, 14 …… Clutch shoe, 14A …… Mounting seat, 15
...... Clutch drum, 15A …… Output shaft, 16 …… Clutch housing, 17 …… Ring gear, 18 …… Swing limit frame, 18
A, 18B …… End 20 …… Cell motor unit 21 …… Axis, 21A …… Screw part, 22 …… Stopper, 23 ……
Holder, 24 …… Flange, 25 …… Toggle spring, 25A, 25B
...... End, 26 …… Operation arm, 26A …… Other end, 26B ……
Tension spring, 26E ... Protrusion, 26F ... Presser seat, 26X ... Extension arm, 27 ... Cell motor, 27B ... Output shaft, 28 ... Pinion, 29 ... Pin jack 30 ... Switch mechanism 31,32 ... … Terminal terminals, 33 …… conductors.

Claims (1)

[Claims] 1. A starter for a small engine that externally transmits a rotational torque to a crankshaft to start it. A cell motor unit having a ring gear connected to the crankshaft and a pinion capable of meshing with the ring gear as an output shaft. The starter unit and the operating arm for swinging the starter unit are pivotally attached to the engine body and can swing within a certain range in a plane orthogonal to the axis of the crankshaft. Has a position holding mechanism that can hold the pinion and ring gear meshing position beyond the inflection point and the meshing disengagement position not exceeding the inflection point. With the habit of returning to a predetermined position on the side of the disengagement position that does not exceed the point, a pair of tar A null terminal is provided, and a conductor having a length that allows simultaneous contact with the pair of terminals is provided on the operation arm for pushing the cell motor unit into the meshing position of the pinion and the ring gear to form a switch mechanism. After pushing the pinion into the meshing position of the ring gear with the, and only the operating arm is returned to the predetermined position by the tension spring, the switch mechanism is turned on and the cell motor is driven to rotate the ring gear and the crankshaft via the pinion. Start the engine,
The pinion receives the drive reaction force of the ring gear that accompanies the start of the engine, moves the cell motor unit to the disengaged position and holds it, and the switch mechanism is turned off to shut off the cell motor unit power. Starting device for small engines characterized by.