JPH08114243A - Fly-wheel brake of engine - Google Patents

Abstract

PURPOSE: To prevent a brake shoe from vibration when it contacts a fly-wheel for improving a brake effect while mitigating the abutting of the tip of the brake shoe against a stage part to improve the durability of the brake shoe. CONSTITUTION: A fly-wheel 5 is provided on the outer peripheral surface with stage parts of a recess part 8, magnetic steel body covered with a cover 31 or the like. A brake shoe 12 fixed to a brake band 11 through a brake lever 16 by a push spring 20 is pressed against the outer peripheral surface of the fly-wheel 5 and constituted to be operated to the brake releasing side against the energizing force of pull spring 20 by an operating lever 21. The base part 25a of a press rod 25 is connected to a long arm part 16a of a brake lever 16 and a guide 26 for the press rod 25 is provided on the outer surface of the brake band 11. When an engine is stopped, the tip part 25b of the press rod 25 presses the intermediate part of the outer surface of the brake band 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine flywheel brake mounted on, for example, a lawn mower.

[0002]

2. Description of the Related Art In the above lawnmowers and the like, flywheel brakes have been conventionally used in order to quickly stop inertial rotation of the engine when the engine is stopped. Within a second), the rotary blade is configured to stop. As a flywheel brake of this type, there is a conventional flywheel brake shown in FIGS. 3 and 4, for example. Here, FIG. 3 is a plan view of an air-cooled vertical axis engine according to a conventional example, and FIG. 4 is an enlarged view of a main part of the flywheel brake in FIG.

As shown in FIGS. 3 and 4, the brake shoe 52 is fixed to the inner surface of the brake band 51.
One end of the brake band 51 is pivotally supported by a support shaft 53,
The other end is pulled by the short arm portion 56b of the brake lever 56 so that the brake shoe 52 can be pressed against the outer peripheral surface 5b of the flywheel 5 of the engine.
Is urged toward the brake operating side by the tension spring 20, and the brake lever 56 can be operated toward the brake release side by the operating lever 21 against the urging force of the tension spring 20. Reference numeral 5a in FIG. 3 is a fan blade that constitutes a flywheel fan, 6 is a ring gear for starting the engine, 7 is a fan cover, and 32 is an igniter for magnet ignition that is operated by the magnetic force of the magnetic steel body 30 in close proximity. Is.

By the way, in this prior art, FIG. 3 and FIG.
As shown in FIG. 3, a recess 8 is provided on the outer peripheral surface of the flywheel 5, and a magnetic steel body 30 covered with an aluminum (non-magnetic body) cover 31 is fixed to the inner bottom surface of the recess 8. This is for avoiding a collision between the magnetic steel body 30 and the brake shoe 52, and for protecting the magnetic steel body 30 having poor mechanical strength by covering it with a non-magnetic cover 31. Further, since the flywheel 5 is made of iron (magnetic material), if the both ends of the magnetic steel body 30 come too close to the both ends of the recess 8, the magnetic field is not sufficiently formed and the original function cannot be exhibited. Therefore, wide voids 8b are formed at both ends of the recess 8 to be sufficiently separated from both ends of the magnetic steel body 30.

[0005]

In the above-mentioned conventional example, the concave portion 8 is used.
Has a structure in which wide gaps 8b are formed at both ends of the magnetic steel body 30 so as to be sufficiently separated from both ends of the magnetic steel body 30. Therefore, when the brake shoe 52 comes into contact with the flywheel 5, a corner of the cover 31, a corner of the recess 8, Since it abuts on a slight step portion of the vehicle and is bounced and vibrates, the braking effect is reduced. In addition, the tip portion of the brake shoe 52 (the rotation direction A of the flywheel 5
Since the upper side) contacts the stepped portion and is worn early, the durability is lowered. The present invention has been made in consideration of such circumstances, and prevents vibration when the brake shoe comes into contact with the flywheel to enhance the braking effect, and
A technical problem is to improve the durability of a brake shoe by mitigating the contact of the tip of the brake shoe with a step.

[0006]

In order to solve the above problems, the present invention is configured as follows. That is, the concave portion 8 is provided on the outer peripheral surface of the flywheel 5, the magnetic steel body 30 covered with the non-magnetic cover 31 is fixed to the inner bottom surface of the concave portion 8, and the brake shoe 12 is fixed to the inner surface of the brake band 11. ,
One end of the brake band 11 is pivotally supported, and a brake lever 16 is used to connect the brake shoe 12 to the outer peripheral surface 5b of the flywheel 5 of the engine E via the brake band 11 so that the brake lever 16 can be pulled. In the flywheel brake of an engine configured to be urged to the brake operating side by the spring 20 and to be operated to the brake releasing side against the urging force of the tension spring 20 by the operation lever 21, the long arm portion of the brake lever 16 is provided. 16a is connected to the base end 25a of the pressing rod 25, and the guide 2 of the pressing rod 25 is attached to the outer surface of the brake band 11.
6 is provided so that the tip end portion 25b of the pressing rod 25 is pressed against the outer surface intermediate portion of the brake band 11 by being restrained by the guide 26 when the brake is actuated.

[0007]

In the present invention, the base end portion 25a of the pressing rod 25 is connected to the long arm portion 16a of the brake lever 16, and the guide 2 of the pressing rod 25 is attached to the outer surface of the brake band 11.
6 is provided and is restrained by the guide 26 when the brake is actuated so that the tip end portion 25b of the pressing rod 25 is pressed against the intermediate portion of the outer surface of the brake band 11, so that the entire brake shoe 12 fly when the brake is actuated. It strongly presses against the outer peripheral surface 5b of the foil 5. Further, by pressing the intermediate portion of the outer surface of the brake band 11, the tip portion of the brake shoe 12 (the direction of rotation of the flywheel 5 A
The upper side) slightly rises, and the tip of the brake shoe 12 is less likely to come into contact with a stepped portion such as a corner of the cover 31 or a corner of the recess 8. Further, even if the tip of the brake shoe 12 comes into contact with the step, the pressing rod 2
Since the tip end portion 25b of 5 presses the intermediate portion of the outer surface of the brake band 11, the brake shoe 52 is prevented from bouncing up and vibrating.

[0008]

As described above, the brake effect can be enhanced by preventing the brake shoe from bouncing up and vibrating, and the rotation of the flywheel and the rotation of the rotary blade can be stopped in a short time. You can Also,
When the brake is activated, the tip of the pressing rod presses the middle part of the outer surface of the brake band, causing the tip of the brake shoe to rise slightly, causing the tip of the brake shoe to become rounded at the corners of the cover or the recesses. Since it is difficult to contact the stepped portion, it is possible to prevent the tip portion of the brake shoe from being worn early, and it is possible to improve the durability of the brake shoe.

[0009]

Embodiments of the present invention will now be described in more detail with reference to the drawings. FIG. 1 is an enlarged view of a main part of a flywheel brake according to the present invention. As shown in FIG. 1, the flywheel brake 10 according to this embodiment has the same basic structure as the conventional example. That is, the flywheel brake 10 includes a brake band 11 having a brake shoe 12 fixed to the inner surface thereof, a brake lever 16 for pressing the brake shoe 12 to the outer peripheral surface 5b of the flywheel 5 via the brake band 11, and a brake lever 11. A tension spring 20 for urging the lever 16 toward the brake actuation side, and an operation lever 21 for operating the brake lever 16 toward the brake release side against the urging force of the tension spring 20 are provided.

As shown in FIG. 1, a recess 8 is provided on the outer peripheral surface of the flywheel 5, and a magnetic steel body 30 covered with a non-magnetic aluminum cover 31 is fixed to the inner bottom surface of the recess 8. There is. Wide voids 8b are formed at both ends of the recess 8,
Both ends of the magnetic steel body 30 are sufficiently separated from both ends of the recess 8. The brake band 11 has one end pivotally supported by a support shaft 13 and the other end 14 locked to a short arm 16b of a brake lever 16.

The brake lever 16 is, as shown in FIG. 1, a bracket 18 formed integrally with the brake base frame 2.
Is swingably supported by a swing support shaft 17. The brake base frame 2 is fixed to the engine body 1 with a plurality of bolts. Long arm 16a of the brake lever 16
Is urged toward the brake operating side by a tension spring 20, and an operation wire 22 is locked to the long arm portion 16a in the opposite direction to the tension spring 20. The operation wire 21 is operated by an operation lever 21 during engine operation. The brake lever 16 is pulled and locked to the brake release side via 22.

In this embodiment, the base end portion 25a of the pressing rod 25 is horizontally swingably connected to the long arm portion 16a of the brake lever 16, and the guide 26 of the pressing rod 25 is provided on the outer surface of the brake band 11. The tip end portion 25b of the pressing rod 25 is configured to press the intermediate portion of the outer surface of the brake band 11 by being restrained by the guide 26 when the brake is operated. Here, the outer surface middle portion means the outer surface of the brake band 11 and the middle portion in the longitudinal direction thereof. Further, the tip of the brake shoe 12 (the upper side of the flywheel 5 in the rotation direction A) is obliquely cut at a predetermined angle θ in order to make smooth contact with the step.

The operation of this embodiment will be described below.
First, while the engine is running, the brake lever 16 is pulled by pulling and locking the operation lever 21 toward the brake release side.
To release the brake. As a result, the brake shoe 12 is separated from the outer peripheral surface 5b of the flywheel. When stopping the engine, the operating lever 21
Release the tow and lock. Then, the operation lever 21 is pulled toward the brake action side by the tension spring 20, and in conjunction with this operation, the ignition circuit (not shown) of the engine is grounded and turned off, or the fuel supply is stopped. .

On the other hand, in parallel with the operation of stopping the engine, the brake lever 16 is rotated to the brake operating side by the tension spring 20, and the short arm portion 16b pulls the tip portion 14 of the brake band 11 to fly the brake shoe 12. It is pressed against the outer peripheral surface 5b of the foil 5. At the same time, the long arm portion 16a of the brake lever 16 pushes the pressing rod 25, and the tip portion 25b of the pressing rod 25 is pushed into the guide 26, but the guide 26 restrains the pushing force. Part of the force acts on the intermediate portion of the outer surface of the brake band 11 as a component force. That is, the tip portion 2 of the pressing rod 25
5b presses the intermediate portion of the outer surface of the brake band 11.

As described above, the tip portion 25b of the pressing rod 25 presses the intermediate portion of the outer surface of the brake band 11 when the brake is operated, so that the entire brake shoe 12 strongly presses the outer peripheral surface 5b of the flywheel 5. In addition, by pressing the outer middle portion of the brake band 11,
The tip of the brake band 11 slightly rises up, and the tip of the brake shoe 12 is less likely to come into contact with a step such as a corner of the cover 31 or a corner of the recess 8. Further, even if the tip portion of the brake shoe 12 comes into contact with the stepped portion, the tip portion 25b of the pressing rod 25 does not come into contact with the brake band 1.
Since the outer middle part of 1 is pressed, the brake shoe 5
Prevents 2 from bouncing up and vibrating.

By thus preventing the brake shoe 12 from bouncing up and vibrating, the braking effect can be enhanced, and the rotation of the flywheel 5 and the rotation of the rotary blade can be stopped in a short time. it can. In addition, the tip portion 25b of the pressing rod 25 has the brake band 1
By pressing the intermediate portion of the outer surface of No. 1, it becomes difficult for the tip portion to come into contact with the stepped portion such as the corner of the cover or the corner of the concave portion, so that the tip portion of the brake shoe can be prevented from being worn early. The durability of the brake shoes can be increased.

FIG. 2 shows a brake band 11 whose front end is restricted by a stopper. That is, this embodiment
A rectangular ring 11a is integrally formed at the tip of the brake band 11, a stopper 18b is integrally formed on the bracket 18, and a stopper 18b is engaged in the rectangular ring 11a. That is, when the brake shoe 12 is worn to a certain extent, the square ring 11a of the brake band 11 is restricted by the stopper 18b. The above rectangular ring 1
An alarm switch may be configured by 1a and the stopper 18b, and the alarm lamp may be turned on when both are in contact with each other.

In the above embodiment, the brake shoe 5
Although the tip end of 2 is obliquely cut at a predetermined angle θ, and the square ring 11a at the tip of the brake band is regulated by the stopper 18b, these are not essential components of the present invention. It can be implemented with appropriate changes.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a flywheel brake according to an embodiment of the present invention.

FIG. 2 is a plan view of a main part of a flywheel brake according to another embodiment of the present invention.

FIG. 3 is a plan view of an air-cooled vertical axis engine equipped with a flywheel brake according to a conventional example.

FIG. 4 is a plan view of a main part of a flywheel brake according to a conventional example.

[Explanation of symbols]

E ... Engine, 5 ... Flywheel, 5b ... Flywheel outer peripheral surface, 8 ... Flywheel outer peripheral surface recessed portion, 10 ... Flywheel brake, 11 ... Brake band, 12 ... Brake shoe, 16 ... Brake lever, 16a ... Brake Lever long arm, 16b ... Brake lever short arm, 20 ... Extension spring, 21 ... Operation lever, 25 ... Push rod, 2
5a ... Base end of pressing rod, 25b ... Tip of pressing rod, 26 ... Guide, 30 ... Magnetic steel body 30, 31 ... Cover.

Claims (1)

[Claims] 1. A flywheel (5) is provided with a recess (8) on its outer peripheral surface, and a magnetic steel body (30) covered with a non-magnetic cover (31) is fixed to the inner bottom surface of this recess (8), The brake shoe (12) is fixed to the inner surface of the brake band (11), one end of the brake band (11) is pivotally supported, and the brake lever (16) is used to brake the brake shoe (12) through the brake band (11). ) Is the outer peripheral surface of the flywheel (5) of the engine (E)
The brake lever (16) is urged toward the brake operating side by the tension spring (20) and the operation lever (21) resists the urging force of the tension spring (20). In the flywheel brake of the engine configured to be operated toward the brake release side, the pressing rod (25) is attached to the long arm (16a) of the brake lever (16).
By connecting the base end portion (25a) of the, the guide (26) of the pressing rod (25) is provided on the outer surface of the brake band (11), by restraining with the guide (26) at the time of braking,
A flywheel brake for an engine, characterized in that the tip portion (25b) of (25) is configured to be pressed against the intermediate portion of the outer surface of the brake band (11).