JP2660806B2 - Scarf - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a muffler attached to a small engine (also referred to as a general-purpose engine) for driving a brush cutter, a generator and the like.

[0002]

2. Description of the Related Art A muffler of this type is generally divided into a muffler body 21 and a lid 22 as shown in FIG. 3, and the muffler body 21 is attached to the engine 1. The muffler main body 21 and the lid 22 are formed by die casting of an aluminum alloy or by sheet metal. In addition, since the muffler is formed of a metal material in this manner, the muffler surface becomes hot to a temperature close to the temperature of the exhaust gas (400 ° C. or higher). Therefore, a muffler cover 23 made of resin is provided to cover the periphery of the muffler. The muffler cover 23 is provided separately from the muffler lid 22 in order to avoid direct transmission of heat.

A muffler having such a structure is described, for example, in Japanese Utility Model Laid-Open No. 62-184124 and Japanese Utility Model Laid-Open No. 4-89819.

[0004]

The above-mentioned conventional muffler has the following disadvantages. That is, since the muffler cover is much larger than the muffler, it hinders the size and weight of the general-purpose engine.

Since the muffler cover is separate from the lid, the number of parts increases, and since the muffler cover needs to be attached separately from the attachment of the lid, it takes time to assemble. Naturally, it takes time to disassemble.

An object of the present invention is to solve the above-mentioned disadvantages of the conventional muffler, and to provide a muffler which has a small number of parts, is easy to assemble, and can be reduced in size and weight.

[0007]

In order to achieve the above object, a muffler according to the present invention comprises: a) a muffler divided into a muffler body attached to an engine side and a lid body thereof; , A roughly square box with one side open
So that it expands slightly from the shape and the periphery of this box
Also serves as a muffler cover with an extended skirt
A plurality of ribs are integrally formed with the thermosetting resin on the surface of the lid, and c) a heat-resistant material such as ceramics or glass wool is formed on the inner surface of the lid. Insulation layer is installed.

[0008] As described in claim 2, d) in front of the lid.
The skirt should have many openings at intervals.
Is preferred .

[0009] As described in claim 3, e) the pre-Symbol thermosetting resin, when the phenolic resin impregnated with glass fibers still good.

[0010]

According to the muffler of the present invention having the above-described structure, the lid (including the muffler cover) is attached to the muffler body with the muffler body attached to the engine in advance. Therefore, the installation and removal of the lid and muffler cover can be completed in one operation, making the operation easier and shorter in time than the conventional muffler where the lid and muffler cover were separate. Is done. Also, from the manufacturing point of view, the number of parts is reduced (several points when including the muffler cover mounting screws)
As a result, assembly is easy, maintenance and management are easy, and manufacturing costs are reduced.

Functionally, high-temperature exhaust gas passes through the inside of the muffler, but is insulated by the heat-resistant heat-insulating material layer described in c) above, and the heat of the exhaust gas is not directly transmitted to the lid. Side temperature is much higher (lower than exhaust gas temperature, 220
About 230 ° C), but because many ribs are provided on the surface, the temperature decreases at the tip of the ribs, and the inner surface of the lid becomes considerably hot, but is formed of a thermosetting resin. Further, since a large number of ribs have a function of reinforcing the lid, it is superior to the above-described conventional muffler due to the fact that there is no deformation due to heat.

By integrating the muffler cover with the lid, the overall volume is reduced as compared to a conventional muffler with a muffler cover (see the phantom line in FIG. 3). As a result, the protruding portion from the engine is reduced, the size and weight are reduced, and the appearance is improved. Also,
The skirt serves as a conventional muffler cover,
The skirt makes the hand or the like touch the metal muffler body.
Block .

According to the muffler of claim 2, wherein the heat inside (especially muffler body) from the opening of the scan car <br/> isolation portion is dissipated, the temperature rise inside the skirt portion is prevented.

According to the third aspect of the present invention, since the lid is formed of a phenol resin impregnated with glass fibers, heat resistance and strength are further improved, and the thermal conductivity of the resin itself is low. The surface temperature of the lid further drops.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a muffler according to the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing a two-cycle general-purpose engine provided with a muffler according to the present invention. FIG. 2 shows an embodiment of a lid integrated with a muffler cover. FIG. 2 (a) is a front view.
FIG. 2B is a rear view, and FIG. 2C is a cross-sectional view taken along line CC of FIG. 2A.

As shown in FIG. 1, a recoil starter (not shown) having an operation knob 2 at an upper end is provided on the rear surface of a central portion of the engine 1. A muffler 10 is provided on the right side of the engine 1. On the left side of Engine 1,
A carburetor 4 is provided, and an air cleaner 5 is connected to the carburetor 4. On the underside of Engine 1,
The fuel tank 3 is fixed.

The muffler 10 is divided into a metal muffler body 11 and a lid 12 made of aluminum die-cast, and the muffler body 11 is attached to the engine 1 with screws.

The lid 12 has a form in which a conventional muffler cover is integrally provided, in other words, a form which also serves as a muffler cover. In this embodiment, the lid 12 is integrally formed of a phenol resin impregnated with glass fibers. In the case of the present example, a molding method is employed in which the SMC, that is, a plate-like phenolic resin material having a constant thickness is heated and molded at the same time as being pressed by a mold. Thermosetting resins include urea resins and melamine resins in addition to phenolic resins. However, the heat deformation temperature is high (250 ° C. or higher) and the bending strength is high (1
From the viewpoint of 4 kgf / mm ² ), a phenol resin containing glass fiber (glass content 30% in this example) is desirable. The lid 12 is a substantially square-shaped conventional lid 2 having an open surface.
2 (FIG. 3) and a box-shaped portion 12a
and a skirt portion 12b extending slightly from the periphery of the opening a in the opening direction.

On the surface of the box-shaped portion 12a, ribs (also referred to as fins) 12c extending in the lateral direction are protruded at regular intervals as shown in FIG. 2 (a), and screw holes (4) of mounting screws 13 are provided. 14a is penetrated, and a recess 14 is provided in which the head 13a of the screw 13 is accommodated.
A cylindrical peripheral wall 14b protrudes so that the third head 13a does not protrude outward. Note that the protrusion amount (height) of the rib 12c is set to 5 mm or more so that a temperature drop sufficiently occurs so that the rib tip does not become hot even if touched by the hand. Many long holes 12d are opened at intervals in the skirt portion 12b so that the heat of the muffler body 11 is dissipated. Reference numeral 14 '(FIG. 2 (c)) is a shallow recess compared to the others,
Although the head 13a of the screw 13 projects, it is not a place where the hand touches the upper part of the lid 12, so there is no problem. An exhaust pipe 12e is integrally formed on the inner surface of the lid 12 as shown in FIGS. 2B and 2C, and one end is opened to the outside as shown in FIG. 2A.

On the inner surface of the box-shaped portion 12a of the lid 12,
A heat insulating material layer 15 (FIG. 2 (c)) also serving as a sound absorbing material is attached over almost the entire surface, and when the peripheral portion of the box-shaped portion 12a of the lid 12 is attached to the peripheral portion of the muffler body 11, the two portions are attached. It is mounted so as to be clamped at the periphery. In this example, the heat insulating material layer 15 is formed by soaking ceramic fibers having a thickness of about 10 mm in a phenol resin liquid and then hot pressing the same according to the inner surface shape of the box-shaped portion 12a. In particular, an exhaust gas outlet (not shown) of the muffler body 11 faces the lid 12, and the high-temperature exhaust gas is supplied to the lid 1.
2, the heat insulating material layer 15 is lined, so that a part of the lid 12 is not heated by the exhaust gas. Although not shown, a sound-absorbing and heat-insulating layer material is also attached to the inner surface of the muffler body 11.

As described above, the muffler 10 according to the present embodiment is configured. Engine 1 of this muffler 10
As shown in FIG. 1, first, the muffler body 11 is attached to the engine 1 via a stay 16 and a set screw 17, and then the heat insulating material layer 15 is attached to the lid 1 as shown in FIG.
2 simply covers the muffler main body 11 in a state in which it is attached to the inner surface of the muffler 2 and fixes it with a plurality of screws 13.

Although the embodiment of the muffler according to the present invention has been described above, the present invention can be implemented as follows.

The direction of the ribs 12c may be vertical, oblique, or vertical and horizontal ribs may intersect.

As the heat insulating material layer 15, asbestos or the like can be used in addition to glass wool.

[0026]

As is apparent from the above description,
The muffler of the present invention has the following effects.

(1) Conventionally, a separate muffler cover is integrated with the lid, and the exhaust pipe and the like are formed separately from the sheet metal lid and attached by welding or the like. Since all parts can be integrally molded of resin, the number of parts is considerably reduced, assembly and disassembly are easy, work time is shortened, maintenance is easy, and manufacturing costs are reduced.

(2) Since the overall volume is reduced as compared with the conventional muffler with a muffler cover, the amount of protrusion from the engine is suppressed, miniaturization and weight reduction are achieved, and the design is expanded. , Appearance is also good.

(3) Since the lid itself is insulated by the heat-resistant heat insulating material layer, the thermal conductivity of the lid itself is low, and the ribs are protruded,
The temperature of the lid surface (the tip of the rib) is so low that it is not hot even when touched by hand, and deformation due to heat hardly occurs due to the reinforcing effect of the rib. Also, the metal muffler whose skirt is hot
-The skirt prevents the hand from touching the body
Is done.

According to the muffler of claim 2 wherein, (4) is radiated from the opening of the skirt portion, the temperature rise in the scan cart portion is prevented.

According to the muffler of the third aspect, (5) Since the lid is formed of a phenol resin containing glass fibers, heat resistance and strength are further improved, and the surface temperature of the lid further decreases.

[Brief description of the drawings]

FIG. 1 is a front view showing a two-cycle general-purpose engine provided with a muffler according to an embodiment of the present invention.

2 (a) is a front view, FIG. 2 (b) is a rear view, and FIG. 2 (c).
FIG. 3 is a sectional view taken along line CC of FIG.

FIG. 3 is a side view showing a conventional general-purpose engine muffler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 10 Muffler 11 Muffler main body 11 12 Lid 12a Box-shaped part 12b Skirt part 12c Rib 12d Long hole 12e Exhaust cylinder 13 Screw 14 Concave part 15 Heat insulation material layer 16 Stay 17 Set screw

Claims (3)

(57) [Claims] 1. A muffler which is divided into a muffler main body attached to an engine side and a lid thereof, wherein the lid has a substantially square box-shaped portion having an open surface.
It is extended so that it slightly expands in the opening direction from the periphery of the box
Heat to form that also serves as a muffler cover with a skirt
With integrally molded with the curable resin, the number of ribs projecting from the integrally with a thermosetting resin on the surface of the lid member, on the inner surface of the lid, ceramic, a heat-resistant heat insulating material layer, such as glass wool is attached A muffler characterized by that. 2. The skirt portion of the lid has an interval.
2. The muffler according to claim 1, wherein a number of openings are provided . 3. The muffler according to claim 1, wherein the thermosetting resin is a phenol resin impregnated with glass fibers.