JP4726766B2 - Forced air cooling engine - Google Patents

Description

  The present invention relates to a forced air cooling engine provided with a cooling fan, a fan cover, a recoil starter, and a recoil starter cover from the bottom above the engine body.

Some walking snowplows have a forced cooling engine that takes in air by rotating a cooling fan and cools the engine body with the taken-in air.
Since the walking snowplow is used in a cold region, the engine temperature rises slowly when the engine is started. For this reason, it is considered that a supercooled state occurs near the jet nozzle of the carburetor, and the water vapor in the air freezes.
Furthermore, since the walking snowplow is used in a snowfall area, it is conceivable that, for example, snow enters the engine during snowfall.

As a countermeasure, a walking type snowplow is known in which a forced cooling engine is configured to prevent overcooling of an intake passage and snow intrusion, and the forced cooling engine is used as a power source (for example, Patent Document 1). reference.).
JP 2005-68735 A

  The walking type snowplow of Patent Literature 1 has a maze portion formed in the middle of a flow path that guides air to the engine. By allowing air to pass through the maze portion, it is possible to remove snow dust in the air or to suppress the flow of air.

However, in order to form the labyrinth part in the middle of the flow path, a plurality of members are required and the configuration becomes complicated.
Furthermore, in order to form the maze part in the middle of the flow path, a space for forming the maze is required, and it is difficult to make the configuration compact.

  An object of the present invention is to provide a forced air-cooled engine that can be simplified in configuration and can be made compact.

The invention according to claim 1 includes a cooling fan, a fan cover, a recoil starter cover, and a recoil starter cover from the bottom above the engine body, and takes in air from a recoil opening of the recoil starter cover, A forced air-cooled engine led into the sub-cooling starter cover and between the recoil starter and the fan cover to prevent overcooling of the forced air-cooled engine and snow intrusion into the forced air-cooled engine / Snow intrusion prevention member is provided , this overcooling / snow intrusion prevention member is composed of a plate facing the bottom surface of the recoil starter cover, a gap is formed between the plate and the bottom surface of the recoil starter cover, The recoil opening is formed on the outer peripheral side of the recoil starter, An introduction opening for introducing air provided in the overcooling / snow intrusion prevention member is disposed immediately below the recoil starter, and the periphery of the introduction opening is an outer periphery of the recoil starter and an inner periphery of the recoil opening. An annular protrusion is provided on the peripheral edge and protrudes upward over the entire periphery .

According to a second aspect of the present invention, the relationship between the total space area S1 of the introduction space for guiding the air formed by the supercooling / snow intrusion prevention member and the recoil starter cover and the total opening area S2 of the recoil opening is expressed as S1 < It is characterized by S2.

In the invention according to claim 1, the overcooling / snow intrusion prevention member is provided in the recoil starter cover. The overcooling / snow intrusion prevention member prevents overcooling of the forced air cooling engine and snow intrusion into the forced air cooling engine.
Only by providing the overcooling / snow intrusion prevention member in the recoil starter cover, overcooling and snow intrusion can be prevented, so that there is an advantage that the configuration can be simplified.

Furthermore, by providing the overcooling / snow intrusion prevention member in the recoil starter cover, it is possible to provide the overcooling / snow intrusion prevention member using the existing space.
Thereby, there is no need to newly form a space for providing the supercooling / snow intrusion prevention member, and there is an advantage that a reduction in size can be achieved.

In addition, in the invention according to claim 1 , the recoil opening is formed on the outer periphery side of the recoil starter, and the periphery of the introduction opening provided in the overcooling / snow intrusion prevention member is arranged between the outer periphery of the recoil starter and the recoil opening. It was arranged between the inner circumference of the.
Therefore, the periphery of the introduction opening can be disposed closer to the recoil starter with respect to the recoil opening.
Accordingly, there is an advantage that the snow that has entered from the recoil opening can be reliably received by the overcooling / snow intrusion prevention member and snow can be prevented from entering the fan cover.

On the other hand, the peripheral edge of the introduction opening can be arranged outside the recoil starter by arranging it between the outer periphery of the recoil starter and the inner periphery of the recoil opening.
Thereby, when the snow received by the supercooling / snow intrusion prevention member is accumulated, there is an advantage that it is possible to prevent the constituent members of the recoil starter from being frozen by the accumulated snow.
As a constituent member of the recoil starter, a connecting member that is provided in the recoil starter and can be connected to the ratchet (the ratchet is a member provided at the upper end portion of the crankshaft) or the like is applicable.

Furthermore, in the invention which concerns on Claim 1 , the cyclic | annular protrusion was provided over the perimeter of the periphery.
Accordingly, when the snow received by the supercooling / snow intrusion prevention member melts, there is an advantage that the melted snow can be prevented from entering the fan cover from the introduction opening.
Furthermore, in the invention according to claim 1, when the snow reliably received by the supercooling / snow intrusion prevention member melts, the melted snow is discharged to the outside through the gap.

In the invention according to claim 2 , the relationship between the total space area S1 of the introduction space for guiding the air and the total opening area S2 of the recoil opening portion is S1 <S2, so that the amount of air introduced is suitably suppressed. Can do.
Thus, there is an advantage that overcooling of the forced air-cooled engine can be prevented by suitably suppressing the amount of air introduced.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Note that “front”, “rear”, “left”, and “right” indicate Fr as the front side, Rr as the rear side, L as the left side, and R as the right side according to the direction viewed from the operator.

FIG. 1 is a perspective view showing a walking type snowplow having a forced air cooling engine according to the present invention.
The walking snowplow 10 includes left and right crawler travel units 12 and 13 on the left and right sides of the body 11, and includes a rotation direction switching device 15 that switches the rotation direction of the left and right crawler travel units 12 and 13, respectively. 15 includes a cover 17 that covers 15, a forced air-cooling engine 19 that transmits rotation to the rotation direction switching device 15 via a travel clutch 18, and left and right swing pipes 21 and 22 that can swing freely on the left and right sides of the body 11. Left and right handles 24 and 25 are provided at the rear ends 21a and 22a of the swing pipes 21 and 22, respectively, and a snow drain plate 26 is provided at the front ends of the left and right swing pipes 21 and 22.

The left crawler traveling unit 12 is a crawler in which a crawler belt 31 is wound around a front drive wheel 28 and a rear idler wheel 29 and the drive wheel 28 is connected to a forced air cooling engine 19 via a rotation direction switching device 15 or the like. It is a traveling part of a formula.
The right crawler traveling unit 13 is a member that is symmetrical to the left crawler traveling unit 12, and the same reference numerals are given to the constituent members and description thereof is omitted.

The rotation direction switching device 15 is connected to a forced air cooling engine 19 via a traveling clutch 18 and is connected to the left and right crawler traveling portions 12 and 13 via a final drive mechanism (not shown).
The rotation of the forced air cooling engine 19 is transmitted to the left and right crawler traveling units 12 and 13 via the traveling clutch 18, the rotation direction switching device 15 and the final drive mechanism.

The cover 17 is formed so as to cover the rotation direction switching device 15 and is disposed between the left and right crawler traveling units 12 and 13.
The cover 17 is attached to the body 11.

  The forced air-cooled engine 19 is a vertical engine having a crankshaft 33 as an output shaft, and the crankshaft 33 is vertically arranged, that is, extended downward.

The left handle 24 extends upward from the rear end 21 a of the left swing pipe 21 toward the rear of the vehicle body, includes a left grip 51 at the rear end, and a travel clutch lever 52 is provided in the vicinity of the left grip 51. ing.
The traveling clutch lever 52 is a lever that switches the traveling clutch 18 between a connected state and a disconnected state.

The right handle 25 extends upward from the rear end 22 a of the right swing pipe 22 toward the rear of the vehicle body, has a right grip 54 at the rear end, and a forward / reverse switching lever 55 is provided in the vicinity of the right grip 54. It has been.
The forward / reverse switching lever 55 is a member constituting a part of the rotation direction switching device 15.

  The walking snowplow 10 travels forward by rotating the left and right crawler travel units 12 and 13 in a state where the left and right grips 51 and 54 are gripped by left and right hands, and the left and right crawler travel units 12 and 13. Reverse drive to reverse.

FIG. 2 is a side view of a forced air cooling engine according to the present invention, and FIG. 3 is a plan view of the forced air cooling engine according to the present invention.
The forced air-cooled engine 19 includes an engine main body 34 including a cylinder block and a crankcase, an engine cover 35 covering the engine main body 34, a fan cover 36 covering the opening of the engine cover 35, and a recoil starter covering the opening of the fan cover 36. A cover 37, a fuel tank 38 disposed on the front side and the right side of the engine cover 35, and an exhaust muffler 39 disposed on the left side of the engine cover 35 are provided.
On the left side of the engine cover 35, an air discharge port 35 a for discharging air is formed at a portion facing the exhaust muffler 39.

4 is a cross-sectional view taken along line 4-4 of FIG. 3, and FIG. 5 is a diagram illustrating a state in which the starter cover, recoil starter, and overcooling / snow intrusion prevention member of FIG. 4 are disassembled.
In the forced air cooling engine 19, a cooling fan 61 is coaxially provided on the crankshaft 33, the cooling fan 61 is covered with a fan cover 36, a recoil starter cover 37 is attached to the fan cover 36, and the recoil starter cover 37 is recoiled. A starter 62 is accommodated, and an overcooling / snow intrusion prevention member 64 is provided in the recoil starter cover 37 and between the recoil starter 62 and the fan cover 36.
The recoil starter 62 is covered with a recoil starter cover 37.

  That is, a cooling fan 61, a fan cover 36, a recoil starter 62, and a recoil starter cover 37 are provided above the engine body 34 from below.

A cooling fan 61 is fitted to the upper end portion 33 a of the crankshaft 33, and a ratchet 71 is attached to the upper surface of the cooling fan 61 with a nut 72.
The ratchet 71 is a member that can be connected to the connecting member 73 by the downward movement of the connecting member 73 when the engine is started and can be disconnected from the connecting member 73 by returning the connecting member 73 to the normal position (upward) after the engine is started. is there.
A state in which the connecting member 73 is moved downward is shown by an imaginary line in FIG.

In the recoil starter 62, a pulley 76 is rotatably bolted to a shaft portion 75 of the recoil starter cover 37.
A starting rope 77 is wound around the pulley 76, a grip 78 (see FIG. 3) is attached to the tip of the starting rope 77, and a connecting member 73 is provided on the pulley 76.
The pulley 76 is covered with an annular cover 84.
The annular cover 84 is formed integrally with the recoil starter cover 37.

Pulling the starting rope 77 with the grip 78 rotates the pulley 76 and moves the connecting member 73 downward. The rotation of the pulley 76 is transmitted to the crankshaft 33 via the connecting member 73 and the ratchet 71.
The crankshaft 33 rotates and the forced air cooling engine 19 is started. When the forced air cooling engine 19 is started, the connecting member 73 returns to the normal position, and the connection between the ratchet 71 and the connecting member 73 is released.
The rotation of the crankshaft 33 is transmitted to the cooling fan 61, and the cooling fan 61 rotates.

The three members of the fan cover 36, the supercooling / snow intrusion prevention member 64, and the recoil starter cover 37 are fastened together with three studs 81 and nuts 82 (see also FIG. 6) and attached to the engine cover 35. .
The supercooling / snow intrusion prevention member 64 is sandwiched between the fan cover 36 and the recoil starter cover 37.
The fan cover 36 has a fan opening 83 formed above the cooling fan 61 and coaxially with the cooling fan 61. The outer diameter D1 of the fan opening 83 is smaller than the outer diameter D2 of the cooling fan 61.

FIG. 6 is a perspective view showing a supercooling / snow intrusion prevention member according to the present invention.
The recoil starter cover 37 is formed in a substantially truncated cone shape by a circular top 85 and an annular inclined portion 86 outside the top 85, and three attachment portions 87 project from the outer periphery of the annular inclined portion 86 at equal intervals. Has been.
Attachment holes 87a are formed in the three attachment portions 87, respectively. The mounting hole 87 a is fitted into the stud 81.

A recoil starter 62 (see FIG. 4) is rotatably supported on the back side of the circular top portion 85.
A plurality of substantially rectangular recoil openings 88 are radially formed in the annular inclined portion 86. In other words, the recoil openings 88 are formed in an annular shape on the outer peripheral side of the recoil starter 62.
Hereinafter, of the recoil openings 88..., Arcs (indicated by imaginary lines) that are in contact with the end 88 a on the recoil starter 62 side will be described as inner peripheries 91 of the recoil openings 88.
The attachment portion 87 has a thick wall thickness T, so that the bottom surface 87 b of the attachment portion 87 is disposed below the bottom surface 86 a of the annular inclined portion 86.

Therefore, as shown in FIG. 4, in the state where the bottom surface 87 b of the mounting portion 87 is placed on the supercooling / snow intrusion prevention member 64, the bottom surface 86 a of the annular inclined portion 86 is against the supercooling / snow intrusion prevention member 64. Located above.
As a result, a gap 89 is formed between the bottom surface 86 a of the annular inclined portion 86 and the supercooling / snow intrusion prevention member 64.
The reason why the gap 89 is formed between the bottom surface 86a of the annular inclined portion 86 and the supercooling / snow intrusion prevention member 64 will be described in detail with reference to FIG.

  The supercooling / snow intrusion prevention member 64 has an outer shape formed in an arc shape, three mounting pieces 65 projecting at equal intervals on the outer periphery, an introduction opening 66 for introducing air is formed in the center, and the introduction opening This is a plate in which an annular protrusion 67 is provided on the peripheral edge 66 a of the portion 66.

The annular protrusion 67 is a projecting piece that is formed over the entire periphery 66 a of the introduction opening 66 and so as to protrude upward.
By providing the annular protrusion 67 on the peripheral edge 66a of the introduction opening 66, it is possible to prevent snow from entering the fan cover from the introduction opening 66.
Furthermore, by providing the annular protrusion 67, when the snow received by the supercooling / snow intrusion prevention member 64 melts, the melted snow can be prevented from entering the fan cover.
The reason why the annular protrusion 67 is provided will be described in detail with reference to FIG.

Attachment holes 65a are formed in the three attachment pieces 65, respectively. The mounting holes 65a are fitted into the studs 81.
The supercooling / snow intrusion prevention member 64 is placed on the annular protrusion 83 a of the fan opening 83 in a state where the mounting holes 65 a are fitted into the studs 81.

Referring back to FIG. 4, the introduction opening 66 for introducing air is disposed immediately below the recoil starter 62, and the peripheral edge 66 a of the introduction opening 66 is the outer periphery 92 of the recoil starter 62 and the inner periphery of the recoil opening 88. 91 (see FIG. 6).
That is, the relationship between the outer diameter D3 of the introduction opening 66, the outer diameter D4 of the recoil starter 62, and the inner diameter D5 of the recoil opening 88 is D4 <D3 <D5.
The inner diameter D5 of the recoil openings 88 is the diameter of the inner periphery 91 of the recoil openings 88.

By setting the relationship between the outer diameter D3 of the introduction opening 66 and the outer diameter D4 of the recoil starter 62 to be D4 <D3, the annular protrusion 67 formed on the peripheral edge 66a of the introduction opening 66 is disposed outside the recoil starter 62. can do.
Thereby, it is possible to prevent the constituent members (such as the connecting member 73) of the recoil starter 62 from being frozen by the snow received by the supercooling / snow intrusion prevention member 64.
The prevention of freezing of the constituent members of the recoil starter 62 will be described in detail with reference to FIG.

Further, by setting the relationship between the outer diameter D3 of the introduction opening 66 and the inner diameter D5 of the recoil opening 88 to be D3 <D5, the circular protrusion 67 of the peripheral edge 66a is connected to the upper end of the recoil opening 88. Can be placed inside.
Thus, the snow that has entered from the recoil opening 88 can be reliably received by the overcooling / snow intrusion prevention member 64.
The reason why the annular protrusion 67 of the peripheral edge 66a is arranged inside the arc connecting the upper ends of the recoil openings 88 will be described in detail with reference to FIG.

  The annular protrusion 67 of the supercooling / snow intrusion prevention member 64 and the annular cover 84 of the recoil starter cover 37 are formed coaxially. The upper end portion of the annular protrusion 67 and the lower end portion of the annular cover 84 are disposed to face each other.

The introduction space 68 formed by the annular protrusion 67 and the annular cover 84 has a total space area S1.
The introduction space 68 is a space that guides air into the fan cover 36.
Further, the recoil opening 88... Has a total opening area S2.
The relationship between the total space area S1 and the total opening area S2 is S1 <S2.
Thereby, the amount of air introduced can be suitably suppressed, and overcooling of the forced air cooling engine 19 can be prevented.
The reason why the relationship between the total space area S1 and the total opening area S2 is S1 <S2 will be described in detail with reference to FIG.

Next, the operation of the supercooling / snow intrusion prevention member 64 will be described with reference to FIGS.
FIGS. 7A and 7B are diagrams illustrating an example in which air is guided to the forced air cooling engine according to the present invention.
In (a), when the forced air cooling engine 19 is driven, the crankshaft 33 rotates in the clockwise direction as indicated by an arrow A. The rotation of the crankshaft 33 is transmitted to the cooling fan 61, and the cooling fan 61 rotates clockwise as indicated by an arrow A.

As the cooling fan 61 rotates, air is taken in from the recoil openings 88 as indicated by an arrow B. The air taken in from the recoil openings 88 is guided to the introduction opening 66 as indicated by an arrow C through the introduction space 68.
The air guided to the introduction opening 66 is guided into the fan cover 36 through the introduction opening 66 as indicated by an arrow D. The air guided into the fan cover 36 is guided to the engine body 34 side.

Here, the relationship between the total space area S1 of the introduction space 68 and the total opening area S2 of the recoil openings 88 is S1 <S2.
Therefore, the amount of air introduced from the introduction space 68 can be suitably suppressed.
As described above, by appropriately suppressing the amount of air introduced from the introduction space 68, overcooling of the forced air cooling engine 19 can be prevented.

In (b), the air guided to the engine body 34 side is guided to a cylinder block (not shown) of the engine body 34. The cylinder block is cooled with the guided air.
The air that has cooled the cylinder block is guided to the exhaust muffler 39 from the air discharge port 35a of the engine cover 35.
The exhaust muffler 39 is cooled by the guided air. The air that has cooled the exhaust muffler 39 is discharged as shown by an arrow E.

FIG. 8 is a diagram for explaining an example of preventing snow from entering the forced air cooling engine according to the present invention.
When snowing when the walking snowplow 10 is used or left, the snow enters the recoil starter cover 37 as indicated by an arrow F from the recoil opening 88.
Here, the introduction opening 66 for introducing air is disposed immediately below the recoil starter 62, and the annular protrusion 67 on the peripheral edge 66a is disposed between the recoil starter 62 and the recoil openings 88.

Therefore, the annular protrusion 67 of the peripheral edge 66a is arranged inside the arc connecting the upper ends of the recoil openings 88. Thus, the snow that has entered from the recoil opening 88 as indicated by the arrow F can be reliably received by the supercooling / snow intrusion prevention member 64.
Therefore, snow can be prevented from entering the fan cover 36.

  When the snow reliably received by the supercooling / snow intrusion prevention member 64 melts, the melted snow is discharged to the outside through the gap 89 as indicated by an arrow G.

Here, the overcooling / snow intrusion prevention member 64 is provided with an annular protrusion 67 on the peripheral edge 66a.
Therefore, when the snow falling on the flat portion 64 a of the supercooling / snow intrusion prevention member 64 melts, the melted snow can be prevented from entering the fan cover 36 from the introduction opening 66.
Thereby, it is possible to prevent snow from entering the fan cover 36 of the forced air cooling engine 19.

Furthermore, the annular protrusion 67 is disposed outside the recoil starter 62 by disposing the annular protrusion 67 between the outer periphery 92 of the recoil starter 62 and the inner periphery 91 (see FIG. 6) of the recoil opening 88. Can do.
Therefore, when the snow received by the flat portion 64a of the supercooling / snow intrusion prevention member 64 is accumulated, the accumulated snow can be prevented from entering the recoil starter 62 side.
Thereby, it can prevent that the connection member 73 etc. with which the recoil starter 62 was equipped with snow are frozen.

As described above, by providing the supercooling / snow intrusion prevention member 64, the supercooling / snow intrusion prevention member 64 prevents overcooling of the forced air cooling engine 19 and snow intrusion into the forced air cooling engine 19.
By simply providing the overcooling / snow intrusion prevention member 64 in the recoil starter cover 37, overcooling and snow intrusion can be prevented, so that the configuration can be simplified.

Further, by providing the overcooling / snow intrusion prevention member 64 in the recoil starter cover 37, it is possible to provide the overcooling / snow intrusion prevention member using the existing space.
Thereby, it is not necessary to newly form a space for providing the supercooling / snow intrusion prevention member 64, and the size reduction can be achieved.

  Although the forced air cooling engine 19 is applied to the walking snowplow 10 in the above embodiment, the forced air cooling engine 19 is not limited to this and can be applied to other working machines. is there.

  Moreover, although the example which made the shape of the recoil opening part 88 substantially rectangular shape was demonstrated in the said embodiment, it is not restricted to this, It can also be made into other shapes, such as a circle.

  The present invention is suitable for application to a forced air-cooled engine having a cooling fan, a fan cover, a recoil starter, and a recoil starter cover from the bottom above the engine body.

It is a perspective view which shows the walk type snow remover provided with the forced air cooling engine which concerns on this invention. It is a side view of the forced air cooling engine which concerns on this invention. It is a top view of the forced air cooling engine which concerns on this invention. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is a figure which shows the state which decomposed | disassembled the starter cover of FIG. 4, a recoil starter, and a supercooling / snow intrusion prevention member. It is a perspective view which shows the overcooling / snow invasion prevention member which concerns on this invention. It is a figure explaining the example which guides air to the forced air cooling engine which concerns on this invention. It is a figure explaining the example which prevents that snow penetrate | invades into the forced air cooling engine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Walking type snow remover, 19 ... Forced air cooling engine, 34 ... Engine main body, 36 ... Fan cover, 37 ... Recoil starter cover, 61 ... Cooling fan, 62 ... Recoil starter, 64 ... Overcooling / snow intrusion prevention member, 66 Introducing opening, 66a ... periphery, 67 ... annular protrusion, 68 ... introducing space, 88 ... recoil opening, 89 ... clearance, 91 ... inner circumference of recoil opening, 92 ... outer circumference of recoil starter.

Claims (2)

A forced air-cooled engine that has a cooling fan, fan cover, recoil starter, and recoil starter cover from above at the top of the engine body, takes air from the recoil opening of the recoil starter cover, and guides the taken air into the fan cover. And
An overcooling / snow intrusion prevention member is provided in the recoil starter cover and between the recoil starter and the fan cover to prevent overcooling of the forced air cooling engine and snow intrusion into the forced air cooling engine. The overcooling / snow intrusion prevention member is composed of a plate facing the bottom surface of the recoil starter cover, and a gap is formed between the plate and the bottom surface of the recoil starter cover.
The recoil opening is formed on the outer peripheral side of the recoil starter,
An introduction opening for introducing air provided in the overcooling / snow intrusion prevention member is disposed immediately below the recoil starter, and a peripheral edge of the introduction opening is between the outer periphery of the recoil starter and the recoil opening. Between the laps,
The forced air-cooling engine according to claim 1, wherein an annular protrusion is provided on the peripheral edge so as to protrude upward over the entire periphery . The relationship between the total space area S1 of the introduction space for guiding the air formed by the supercooling / snow intrusion prevention member and the recoil starter cover and the total opening area S2 of the recoil opening is S1 <S2. The forced air-cooled engine according to claim 1 .

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