JPH0732929Y2 - Air vent device for gear blutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an air vent device for a carburetor in which the atmosphere acts on the fuel chamber of a circulating carburetor.

[Prior Art] Conventionally, in this type of air vent device, in order to maintain a constant pressure (atmospheric pressure) in the upper space of the fuel chamber of the carburetor, the upper space of the fuel chamber is directly exposed to the atmosphere through the air vent passage. Some are open. On the other hand, the upper space of the fuel chamber is opened to the intake passage between the air cleaner and the carburetor to purify the air sucked into the air vent passage (see, for example, Japanese Patent Publication No. 60-33991).

[Problems to be solved by the invention] However, in the case where the upper space of the fuel chamber of the carburetor is directly opened to the atmosphere, dust and dirt in the atmosphere may be mixed into the fuel or the air vent passage may be clogged. . Therefore, in order to purify the air sucked into the air vent passage, it is necessary to separately provide an air cleaner for the air vent, resulting in a complicated structure.

On the other hand, in the case where the upper space of the fuel chamber of the carburetor is opened to the intake passage between the air cleaner and the carburetor, the pressure in the intake passage between the air cleaner and the carburetor changes subtly depending on the operating state, so the upper portion of the fuel chamber It is difficult to keep the space pressure constant. That is, the structure for opening the air vent passage to the intake passage is
As shown in Japanese Patent Laid-Open No. 60-33991, it cannot be used in a case where a phase difference occurs between the pressure of the bench lily part of the carburetor (fuel blowout main port part pressure) and the pressure in the upper space of the fuel chamber. In particular, in the case of the circulation type carburetor targeted by this invention, since the fuel tank and the fuel chamber upper space communicate with each other by the return pipe, the change in intake passage pressure and tank pressure is Of course,
Since a phase difference occurs, a phase difference occurs between the pressure of the bench lily part of the carburetor and the pressure of the upper space of the fuel chamber, which makes it difficult to stably supply fuel.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to maintain a constant pressure in the air vent passage to stabilize the fuel supply and the performance of the carburetor. An object of the present invention is to provide an air vent device for a carburetor capable of supplying purified air.

[Means for Solving the Problems] In order to achieve the above object, the present invention first forms a rib-shaped holding wall for holding one side surface of a cleaner element of an air cleaner integrally with an air cleaner case, and uses this holding wall. A small chamber is provided which is separated from the downstream chamber of the cleaner chamber, and the small chamber communicates with the upstream chamber of the cleaner chamber through small gaps formed in the vertical and horizontal directions, respectively. The small chamber is divided into a first small chamber and a second small chamber communicating with the first small chamber with rib-shaped partitions, and the first small chamber is communicated with the air vent passage of the carburetor through the connection port. On the other hand, the second small chamber is connected to the atmosphere opening hole, and a filter element through which air passes is attached to the first small chamber.

[Operation] According to the present invention, the small chamber partitioned from the downstream chamber of the cleaner chamber by the rib-shaped retaining wall integrally formed with the air cleaner case so as to retain one side surface of the cleaner element is provided in the vertical direction and the left-right direction. Since it is communicated with the upstream chamber of the cleaner chamber through a small gap formed in the direction, the connection port communicating with the air vent passage of the carburetor is the air intake port in the carburetor air cleaner in the preceding stage due to the labyrinth effect in the gap. Even when it is separated from the air vent, the connection port does not become a negative pressure, and it is possible to maintain the small chamber at atmospheric pressure through the atmosphere opening hole. And the pressure in the upper space of the fuel chamber are maintained at atmospheric pressure or almost atmospheric pressure, and the fuel supply is stabilized.

Further, since the filter element is attached to the first small chamber, the outside air introduced into the first small chamber via the second small chamber is purified, so that the air introduced into the air vent passage is purified. It Moreover, since the first and second small chambers are integrally formed in the air cleaner, it is not necessary to separately provide an air cleaner for the air vent.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an air cleaner, in which an air cleaner case 1 is connected to a carburetor 2.
The cleaner cap 3 is fitted in the cleaner case 1. A cleaner chamber 4 is formed by the cleaner case 1 and the cleaner cap 3, and the cleaner chamber 4 is divided into an upstream chamber 4a and a downstream chamber 4b by a cleaner element 5 for purifying combustion assisting air. There is. The cleaner element 5 has ribs 1b whose front and rear surfaces 5a and 5b are integrally formed with the lattice-shaped holder 6 and the cleaner case 1.
Is held between. On the other hand, the four side surfaces 5c, 5d of the cleaner element 5 (the two left and right side surfaces are not shown)
Are held by the rib-shaped holding wall 20 and the peripheral wall 1a of the cleaner case 1. The cleaner case 1, the cleaner cap 3 and the holder 6 are made of synthetic resin. The holder 6 is fitted and locked in a slit portion 1c formed in the peripheral wall 1a of the cleaner case 1 by a plurality of convex portions 6a formed integrally with the holder 6.

An intake port 9 for introducing air A into the upstream chamber 4a of the cleaner element 5 is provided at the upper end of the cleaner cap 3. An upstream air cleaner (not shown) for removing large dust and dirt is separately provided on the upstream side of the intake port 9. The air outlet of the upstream air cleaner and the intake port 9 are air pipes. It is in communication. On the other hand, on the downstream side of the cleaner case 1, purified air C is supplied to the downstream chamber 4b.
An air outlet 10 is provided to lead out from the inside to the carburetor 2. Reference numeral 11 denotes a disc-shaped blowback prevention plate, which has a function of preventing blowback from the carburetor 2 from colliding with the cleaner element 5 and returning it to the engine side.

The rib-shaped holding wall 20 horizontally projects from the lower end of the cleaner case 1 toward the cleaner cap 3, and extends over the entire width of the cleaner case 1 in the left-right direction D as shown in FIG. 2 (front view). And extends integrally with the cleaner case 1. Below the holding wall 20, there is provided a small chamber 24 which is located away from the intake port 9 in FIG. 1 and which is open toward the cleaner cap 3 side. This small room 24
Is partitioned by the holding wall 20 from the downstream chamber 4b, and the space inside the cleaner case 1 is defined by the first labyrinth forming piece 21 which is continuous with the holding wall 20 in FIG. It is divided into 25. The concave portion 20b provided in the holding wall 20 meshes with the convex portion (not shown) of the holder 6,
It serves as a guide for correctly assembling the holder 6.

On the other hand, in the cleaner cap 3 shown in FIG. 3, a second horizontal labyrinth forming piece 22 is provided in parallel with the holding wall 20 (FIG. 2) facing the holding wall 20 with a slight displacement. The third labyrinth forming piece 23, which is perpendicular to and is parallel to the labyrinth forming piece 21 (see FIG. 2), is formed integrally. As shown in FIG. 1, when the cleaner cap 3 is fitted to the cleaner case 1, the side end 20a of the rib-shaped holding wall 20 is superposed on the tip portion 22a of the second labyrinth forming piece 22 from above. A small gap 26a is formed in the vertical direction B between the holding wall 20 and the labyrinth forming piece 22. On the other hand, as shown in FIG. 4 which is a sectional view taken along the line IV-IV of FIG. 1, a small gap 26b is formed in the left-right direction D by the first labyrinth forming piece 21 and the third labyrinth forming piece 23. It Through these gaps 26a (Fig. 1) and 26b,
The small chamber 24 shown in FIG. 1 and the upstream chamber 4a of the cleaner element 5 communicate with each other.

As shown in FIG. 4, a vertical rib-shaped partition 50 is integrally formed with the cleaner case 1 in the center of the small chamber 24. The partition 50 divides the small chamber 24 into a first small chamber 24a and a second small chamber 24b. On the other hand, the cleaner cap 3 is provided with a communication chamber 51 that allows the first and second small chambers 24a and 24b to communicate with each other in the cleaner cap 3.

The cleaner case 1 is provided with a rectangular air opening hole 53 for communicating the second small chamber 24b with the atmosphere, while the first small chamber 24a is provided with the air vent passage 32 of the carburetor 2 shown in FIG. A connection port 60 communicating with the above is integrally formed as shown in FIG. In the first small chamber 24a,
Air Aa flowing from the second small chamber 24b toward the first small chamber 24a
A filter element 52 through which the filter passes is attached. The filter element 52 is made of a small piece of urethane foam, and is elastically fitted into the first small chamber 24a. This first
Inside the small chamber 24a of the cleaner case 1 is a rib-shaped small piece 55.
The small piece 55 forms a space 80 downstream of the filter element 52.

The connection port 60 of the cleaner case 1 is connected to the air vent passage of the carburetor through the air vent pipe 29 shown in FIG.
Connected to 32. As is well known, the air vent passage 32 communicates with the upper space 31 of the fuel chamber 30 of the carburetor 2. The fuel chamber 30 communicates with a bench lily 39 via a main jet 37 and a main port 38. Reference numeral 40 is a needle that is locked to a valve 70 that is operated to move up and down from the outside by a clip 71 or the like, 41 is a yoke valve, and 42 is a fuel tank. The fuel tank 42 is connected to the fuel chamber through the fuel pump 43.
It communicates with 30. Further, the fuel overflowing the weir 44 provided in the fuel chamber 30 returns to the fuel tank 42 through the return pipe 45. 46 is an open air breather, and F is a fuel.

The cleaner case 1 shown in FIG. 2 is provided with a recess 56, and the recess 56 is fitted to the protrusion 57 of the cleaner cap 3 shown in FIG. 3 to connect the cleaner cap 3 and the cleaner case 1 to each other. It is positioned.

Next, the operation of the above configuration will be described.

During operation of the engine, the air A in FIG. 1 enters the cleaner chamber 4 through the intake port 9, is purified by the cleaner element 5, and is supplied to the carburetor 2. Fuel is added at the carburetor 2 portion and supplied to the engine. To be done. On the other hand, the air vent passage 32 shown in FIG.
A small amount of air Aa is introduced through the small chamber 24b, the communication chamber 51, the first small chamber 24a, the connection port 60 and the air vent pipe 29 of FIG.

By the way, when the connection port 60 in FIG. 1 is separated from the air intake port of the air cleaner for the preceding stage not shown as described above as in this embodiment, the inside of the connection port 60 will be negative pressure in the conventional case. Therefore, the air vent passage 32
It was difficult to keep the internal pressure (Fig. 5) constant.
On the other hand, in this invention, the small chamber 24 has a small gap 26a, 26a.
The upstream chamber 4 of the cleaner element 5 via b (Fig. 4)
Since it is communicated with a, a labyrinth effect is produced in the gaps 26a, 26b, which causes the pressure in the small chamber 24 to increase even though the connection port 60 and the intake port of the air cleaner in the preceding stage are separated. Maintained at atmospheric pressure. That is, regardless of the position of the intake port of the air cleaner, the pressure in the air vent passage 32 in FIG. 5 can be maintained at atmospheric pressure, so that the pressure in the upper space 31 of the fuel chamber 30 is a constant value almost equal to atmospheric pressure. Therefore, the performance of the carburetor 2 becomes stable.

On the other hand, a filter element 52 is provided in the first small chamber 24a of FIG.
The air introduced through the air vent 53
Aa is purified by the filter element 52, and thus the air Aa introduced into the air vent passage 32 (Fig. 5) is purified. Moreover, the first and second small chambers
Since 24a and 24b are integrally formed in the cleaner case 1, it is not necessary to separately provide an air cleaner for the air vent, and the structure can be simplified. Of course, even when the air flow from the atmosphere to the fuel chamber upper space 31 described above flows from the fuel chamber upper space 31 to the atmosphere, the fuel chamber upper space 31
Since it quickly becomes atmospheric pressure, it has a structure that is stable as the performance of the carburetor.

The sealing performance is improved by eliminating the gaps 26a, 26b (FIG. 4) in FIG. 1 and keeping the small chamber 24 in a sealed state. However, when this is done, a rubber seal is provided at the mating portion of the cleaner case 1 and the cleaner cap 3. And so on, which makes the structure complicated and impractical. In the combination of the air cleaner and the carburetor having the structure shown in this invention, the seal utilizing the above labyrinth is practically sufficient.

In the above embodiment, the side end 20a of the rib-shaped holding wall 20 of FIG.
And the tip 22a of the second labyrinth forming piece 22 are overlapped so as to form a gap 26a, but instead of this, both 20a,
22a may be attached to each other to form the gap 26a. Further, the second labyrinth forming piece 22 is removed, and the rib-shaped holding wall 20 is extended to the cleaner cap 3 side so that the holding wall 20 and the inner surface 3a of the cleaner cap 3 (FIG. 1).
A gap 26a may be formed between and.

In this embodiment, the cleaner case 1 shown in FIG. 2 has a recess 56 and a protrusion 58, and the cleaner cap 3 shown in FIG.
Since the 57 and the recess 59 are provided, the cleaner cap 3
Is not accidentally fitted into the cleaner case 1 upside down. Further, if the recess 56, the protrusion 58, the protrusion 57, and the recess 59 are provided at different positions in the air cleaner of another product, the cleaner caps may be erroneously fitted in the cleaner cases of different products. There is no fear.

Although another air cleaner (not shown) at the front stage for removing large dust is provided at the front stage of the air cleaner shown in FIG. 1, but the air cleaner at the front stage may not be provided.

[Effect of the Invention] As described above, according to the present invention, the pressure in the upper space of the fuel chamber of the carburetor is maintained at a constant value almost equal to the atmospheric pressure, regardless of the position of the intake port of the air cleaner, and The performance of can be stabilized. Further, since it is not necessary to separately install an air cleaner for the air vent, it is possible to purify the air introduced into the air vent passage while simplifying the structure.

[Brief description of drawings]

1 is a sectional view showing an assembled state along line II in FIGS. 2 and 3, and FIG. 2 is a front view of an air cleaner case,
FIG. 3 is a front view of the cleaner cap, and FIG. 4 is a front view of FIG.
IV-IV line sectional drawing, FIG. 5 is sectional drawing which shows a carburetor. 1 ... Air cleaner case, 2 ... Calibrator, 3 ...
Cleaner cap, 4 …… Cleaner room, 4a …… Upstream room,
4b: downstream chamber, 5: cleaner element, 5c: one side, 20: retaining wall, 24: small chamber, 24a: first small chamber, 2
4b ... second chamber, 26a, 26b ... gap, 32 ... air vent passage, 50 ... partition 52 ... filter element, 53 ...
… Atmosphere opening hole, 60 …… Connection port, Aa …… Air.

Claims (1)

[Scope of utility model registration request] 1. An air cleaner case connected to a circulating carburetor in which an upper space of a fuel chamber and a fuel tank communicate with each other through a return pipe, a cleaner cap fitted to the air cleaner case, and the cleaner case. A cleaner element that divides a cleaner chamber formed by a cleaner cap into an upstream chamber and a downstream chamber; a rib-shaped holding wall that is integrally formed with the air cleaner case and holds one side surface of the cleaner element; and the air cleaner. A small chamber, which is provided in the case and is partitioned from the downstream chamber of the cleaner chamber by the rib-shaped holding wall, and communicates with the upstream chamber of the cleaner chamber through small gaps formed in the vertical direction and the horizontal direction, respectively. The small chamber partitioned by the holding wall from the downstream chamber of the cleaner chamber is the first small chamber and the first small chamber. The rib-like partition piece for partitioning the second chamber communicating with the chamber of a connection port for communicating the first chamber to the air vent passage of the circulating carburetor, the second
An air opening hole for communicating the small chamber with the atmosphere, and a filter element that is mounted in the first small chamber and that purifies the air introduced from the air opening hole and flowing from the second small chamber toward the first small chamber. Carburetor air vent device.