JP2001317408A - Automatic starting device of carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic starting device of a carburetor allowing improvement of hot restartability of an engine, reduction of manufacturing cost, and compactification. SOLUTION: A wax holder F has openings at its both ends and a female screw F1 in the upper part. A cover holder J comprises a first cylindrical part J2 in a closed-end cup shape and a second cylindrical part J5 in a closed-end cup shape formed on the outer periphery of the first cylindrical part J2 with a clearance W. The lower end of the first cylindrical part J2 is provided with a male screw J4, and the first cylindrical part J2 is provided with a heater 13 connected to terminals T1 and T2, a collar K, a temperature-sensitive driving member C, or the like. An annular space part R in a substantially closed shape is formed along a longitudinal direction X-X of the temperature-sensitive driving member C between an upper cylindrical part F4 of the wax holder F and the second cylindrical part J5 of the cover holder J.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor for controlling the concentration and amount of an air-fuel mixture supplied to an engine. The present invention relates to an automatic starter for a carburetor that supplies a starting air-fuel mixture to an engine and gradually and automatically reduces the starting air-fuel mixture as the engine warms up.

[0002]

2. Description of the Related Art A conventional automatic starter for a vaporizer will be described with reference to FIG. Reference numeral 1 denotes a carburetor body formed with an intake passage 2 penetrating therethrough. The intake passage 2 is opened and closed by a throttle valve 3. A float chamber main body 4 is disposed below the vaporizer main body 1, and a float chamber 5 is formed by the vaporizer main body 1 and the float chamber main body 4. In the float chamber 5, a float (not shown), a float valve, A constant fuel level is formed by a constant level control mechanism comprising a valve seat. Reference numeral 60 denotes a wax holder insertion concave portion which is concavely formed downward from the upper end of the base main body P (the carburetor main body 1), and a start valve guide hole 61 is further concavely formed from the bottom thereof. A starting fuel passage 62 is provided at the bottom of the starting valve guide hole 61 and extends below the fuel level in the float chamber 5, and a starting air passage connected to the intake passage 2 upstream of the throttle valve 3 is formed on a side of the starting fuel passage 62. 63 and a starting air-fuel mixture passage 64 connected to the intake passage 2 downstream of the throttle valve 3 are opened. And the starting fuel passage 6
2 is controlled by a needle N attached to a start valve V movably arranged in a start valve guide hole 61,
The starting mixture passage 64 and the starting air passage 63 are controlled by the lower end VB of the starting valve V. The wax holder 65 has a cylindrical shape with an opening at the top and bottom, and the lower cylinder portion is the base body A.
The female screw 6 is inserted into the wax holder insertion concave portion 60, and the inner circumference of the upper cylindrical portion protruding from the base main body A is provided.
5A is formed. And this wax holder 65
The female screw 65A has an upper bottom portion 66A, and a bottomed cup-shaped cover holder 66 that opens downward is screwed and arranged. In the cover holder 66, an upper bottom 66 is provided.
A heater (PTC heater) 68 sandwiched between the terminals 67A and 67B toward A, and a collar 69 abutted thereon.
Is arranged. C is a temperature-sensitive driving member, in which a thermo-expandable material such as paraffin or olefin is enclosed, and a change in their volume is output as a stroke displacement of the output rod C1. Are arranged facing the collar 69. D is a transmission member that moves in synchronization with the displacement of the output rod C1, and the downward displacement of the transmission member D is transmitted to the starting valve V via the spring force of the first spring S1, and the transmission member D In the upward displacement, the starting valve V is mechanically pulled up by the locking flange D1. The transmission member D is urged upward by a second spring S2 having a spring force stronger than the spring force of the first spring S1, whereby the temperature-sensitive drive member C including the output rod C1, the collar 69, and the like. Heater 6 including the terminals 67A and 67B
8 is elastically pressed and fixed to the upper bottom 66A of the cover holder 66. Then, the stay 70 is engaged with the groove 65 </ b> B formed on the outer periphery of the wax holder 65, and the stay 70 is screwed to the base body A, whereby the starting device is fixed to the base body A. Reference numeral 71 denotes a heat insulating cover which is disposed so as to surround the outer periphery of the wax holder 65 and the outer periphery of the cover holder 66.
1, a downward opening 71A is formed, and a terminal 67A,
A lead wire 72 connected to 67B extends outward through this opening 71A.

When the temperature of the engine atmosphere is equal to or higher than a predetermined temperature, the volume of the heat-expandable material sealed in the temperature-sensitive driving member C expands greatly, and the output rod C1 protrudes largely downward. . According to this, the starting valve V is disposed below the starting valve guide hole 61, the starting fuel passage 62 is closed by the valve portion VA, and the starting air passage 63 and the starting mixture passage 64 are connected to the side of the starting valve V. Is held closed. According to the above description, during the start operation of the engine, the starting air-fuel mixture is not supplied to the engine from the starting air-fuel mixture passage 64, and the air-fuel mixture corresponding to a temperature state equal to or higher than a certain temperature is supplied via the fuel supply system of the carburetor. Supplied to the organization.

[0004] Next, in a state where the engine ambient temperature is equal to or lower than the predetermined fixed temperature, the volume of the thermal expansion / contraction material sealed in the temperature-sensitive driving body C decreases, and the protrusion of the output rod C1 decreases. According to this, the transmission member D moves upward so as to contact the output rod C1 by the spring force of the second spring S2, and the start valve V moves upward in synchronization with the transmission member D. And according to the upward movement of the starting valve V,
The valve portion VA opens the starting fuel passage 62 and the effective opening area of the starting fuel passage 62 is determined by the needle N, while the starting air passage 63 and the starting air-fuel mixture passage 64 are opened by the side of the starting valve V. . In such a state, when the engine start operation is performed, the starting fuel passage 62
The starting fuel inside is determined by the effective opening area controlled by the needle N and is sucked into the starting valve guide hole 61, while the starting air corresponding to the opening by the starting valve V is supplied from the starting air passage 63 to the starting valve guide. It is sucked into the hole 61.
Then, in the starting valve guide hole 61, the starting fuel and the starting air are mixed to form a starting air-fuel mixture. The starting air-fuel mixture corresponds to the opening of the starting valve V and enters the starting air-fuel mixture passage 64. The starting air-fuel mixture is sucked and added to the fuel supplied from the fuel supply system of the carburetor, whereby the engine is started at a low temperature.

After the engine is started, the engine enters a warm-up operation. During the warm-up operation, the heater 68 is energized through the terminals 67A and 67B.
According to the above description, the heater 68 generates heat, and this heat is transmitted to the temperature-sensitive driving body C via the collar 69 to warm the temperature-sensitive driving body C. When the temperature-sensitive driving body C is heated, the heat-expandable material enclosed therein expands in accordance with the temperature to be heated, and the protrusion of the output rod C1 gradually increases. According to the increase in the protrusion of the output rod C1, the transmission member D
And the starting valve V gradually moves downward to start the fuel passage 6.
2. The opening area of the starting air passage 63 and the starting air-fuel mixture passage 64 is gradually reduced, and the starting valve V closes and holds the passages 62, 63 and 64 in a state where the output rod C1 protrudes greatly.

Accordingly, by controlling the heat generated by the heater 68 in accordance with the warm-up operation characteristics of the engine, the temperature-sensitive driving member C is controlled.
, The opening position of the start valve V can be appropriately controlled by adjusting the protrusion of the output rod C1. Therefore, the mixture for warm-up operation appropriate for the warm-up operation of the engine is directed to the engine. It can be supplied, and a good warm-up operation after starting can be obtained.

At the end of the warm-up operation in which the engine is sufficiently warmed up, the output rod C1 is held so as to protrude largely because the temperature-sensitive driving body C has been sufficiently warmed up. Can close and hold the starting air passage 63, the starting fuel passage 62, and the starting air-fuel mixture passage 64, stop the supply of the air-fuel mixture from the starting air-fuel mixture passage 64, and thereby satisfactorily operate the engine thereafter. Further, in a state where the engine is stopped after the engine has been continuously operated, the heat-sensitive driving body C is sufficiently warmed and held by the heat retaining cover 71, so that the hot restartability for restarting the engine immediately after the stop is provided. It is possible.

[0008]

According to such a conventional automatic starter for a vaporizer, a heat retaining cover 71 for keeping the temperature-sensitive drive member C warm is disposed around the wax holder 65 and the cover holder 66. Since the heat retaining cover 71 is formed with an opening 71A for passing the lead wire 72 to the outside, it is difficult to form a closed space, and the heat retaining property of the heat-sensitive driving member C cannot be greatly improved. or,
It is necessary to prepare a special new heat insulating cover 71 and assemble it, which increases the number of parts and the number of assembling steps and does not reduce the manufacturing cost. Can not.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the carburetor capable of achieving a further improvement in hot restartability, a reduction in manufacturing cost, and a compact automatic starter. To provide an automatic starting device.

[0010]

In order to achieve the above object, an automatic starter for a carburetor according to the present invention displaces a start valve in synchronization with a temperature-sensitive drive member which is displaced in accordance with the heat generated by a heater. The opening of the starting air passage, the starting fuel passage and the starting air-fuel mixture passage is controlled by the displacement of the starting valve, and the starting air-fuel mixture toward the starting air-fuel mixture passage is automatically controlled. A cylindrical wax holder having a female screw formed at an upper opening end, a cup-shaped bottomed heater, and a heater for heating a temperature-sensitive driving member via a collar at an upper bottom thereof, and electrically connected to the heater A first cylindrical portion having a terminal and having a male screw formed at a lower end; and a cover holder integrally formed with a second cylindrical portion formed at an outer periphery of the first cylindrical portion with a gap and opening downward. , Said wash The male screw of the cover holder is screwed into the female screw of the holder, and the temperature-sensitive driving member disposed inside is elastically pressed and arranged on the collar via the transmission member to which the start valve is locked, and the wax is provided. The lower cylinder portion of the holder is housed and arranged in the wax holder housing hole of the base body, and the start valve is inserted and arranged in a start valve guide hole provided continuously with the wax holder housing hole, and the first cylinder portion of the cover holder is arranged. The first feature is that a substantially sealed annular space is formed between the upper cylinder of the wax holder and the second cylinder of the cover holder along the longitudinal direction XX of the temperature-sensitive driving member. I do.

Further, the present invention is characterized in that, in addition to the first feature, an annular space is formed by contacting a lower end of a second cylindrical portion of the cover holder with a base body.

According to the present invention, in addition to the first feature, the lower end of the second cylindrical portion of the cover holder abuts against the annular flange of the wax holder to form an annular space. Features.

Further, the present invention has a fourth feature in that, in addition to the first feature, the cover holder is formed of a synthetic resin material.

Further, according to the present invention, in addition to the first feature,
A fifth feature is that a mounting stay is formed integrally with the cover holder, and the cover holder is screwed and fixed to the base body via the mounting stay.

[0015]

According to the first feature of the present invention, the longitudinal direction X- of the temperature-sensitive driving member is set between the first tubular portion of the cover holder, the upper tubular portion of the wax holder, and the second tubular portion of the cover holder.
A substantially sealed annular space along X is formed, which keeps the heat of the heat-sensitive driving body. Since this space forms a closed shape, the heat retention can be greatly improved and the hot restartability of the engine can be improved. It can be greatly improved. Further, since no special heat insulating cover is required, reduction in manufacturing cost and downsizing can be achieved.

According to the second feature of the present invention, since the lower end of the second cylindrical portion of the cover holder is in contact with the base body, a closed annular space can be easily formed.

According to the third feature of the present invention, since the lower end of the second cylindrical portion of the cover holder is in contact with the annular flange of the wax holder to form a closed annular space, it is assembled to the base body. An annular space can be formed before welding, and the workability of assembling can be improved.

According to the fourth feature of the present invention, since the cover holder is formed of a synthetic resin material, a temperature drop in the annular space can be suppressed, and the heat-retaining property of the heat-sensitive driving body can be further improved.

According to the fifth aspect of the present invention, since the cover holder is screwed and fixed to the base body via the mounting stay, no new parts are required for mounting.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS F is a cylindrical wax holder.
Both ends are open, and a female screw F1 is formed at the upper open end.
J is a cover holder consisting of: The cover holder J includes a first cylindrical portion J2 having an upper bottom portion J1. The upper bottom portion J1 is provided with a heater 13 which is electrically connected to and held by terminals T1 and T2. It is arranged so as to project into the hole J3. Also, the first cylindrical portion J
A collar K made of a material having excellent heat conductivity (for example, aluminum, copper, or the like) is arranged in the collar 2, and the collar K is arranged in contact with the terminal T2. Then, a male screw J4 screwed to the female screw F1 of the wax holder F is formed. A bottomed cup-shaped second cylinder J5 is integrally formed on the outer periphery of the first cylinder J2 with a gap W, and a lower end J6 of the second cylinder J5 is open. Further, a mounting stay J7 is formed to extend laterally from the cover holder J, and a mounting hole J8 is formed in the mounting stay J7. That is, the first cylindrical portion J2 and the second cylindrical portion J5 are formed substantially concentrically with the cover holder J, and the mounting stay J7 is integrally formed.

D is a bottomed cup-shaped transmission member having an opening at the upper part of the cylindrical part D1 and having a bottom part D2. A projecting part is formed further below the bottom part D2 and faces upward at the lower end of the projecting part. A locking flange D3 is formed. A spring locking flange D4 is formed on the outer periphery near the upper end of the cylindrical portion D1.

The starting valve V provided with the needle N has a reduced step portion V1 facing downward and formed inside the upper portion thereof, and the locking flange D3 of the transmission member D is engaged with the reduced step portion V1 of the starting valve V. Then, the first spring S1 contracted and held therein abuts and holds the locking flange portion D3 toward the reduction step portion V1, whereby the starting valve V is integrally attached to the transmission member D.

The automatic starter is assembled as follows. Terminal T on top bottom J1 of cover holder J
1, a heater 13 sandwiched by T2 is arranged,
The transmission member D having the collar K, the heat-sensitive driving member C, and the starting valve V is further directed from the lower opening of the first cylinder portion J2 into the first cylinder portion J2. The second spring S2 is disposed on the stopper collar D4, and then the wax holder F is inserted toward the first cylinder J2,
The female screw F1 of the wax holder F is screwed to the male screw J4 of the cover holder J. According to the above, the second spring S2 is contracted between the inner step F2 of the wax holder F and the spring locking flange D4 of the transmission member D, whereby the transmission member D is connected to the temperature-sensitive drive member C and the collar. K is pressed and held toward the upper bottom part J1 of the cover holder J. At this time, the position of the starting valve V in the longitudinal direction is adjusted by screwing the wax holder F.

Then, the lower cylindrical portion F3 of the wax holder F in the sub-assembly state of the automatic starter is inserted into a wax holder accommodating hole A1 which is recessed in the base body A, and the starting valve V is connected to the starting valve guide hole 61. Insert and place inside. Then, in this state, the screw Y is screwed toward the screw hole A3 of the base member A via the mounting hole J8 formed in the mounting stay J7 of the cover holder J.

According to the above, the cover holder J is fixed to the base body A, and the cover holder J fixes the wax holder F toward the base body A, whereby the automatic starting device is fixedly arranged on the base body A.

According to the above assembly, the lower end J6 of the second cylindrical portion J5 of the cover holder J is disposed in contact with the annular portion A2 of the base body A. An annular space of a gap W that forms a substantially sealed shape along the longitudinal direction XX of the heat-sensitive driving member C by the outer periphery of the cylindrical portion J2, the outer periphery of the upper cylindrical portion F4 of the wax holder F, and the inner periphery of the second cylindrical portion J5. A portion R is formed. The contact of the second cylindrical portion J5 with the base body A is not limited to the outer surface, but may be in a flat surface. In short, it is sufficient that a substantially closed space is formed.

As described above, according to the present invention, the second cylindrical portion J5 of the cover holder J is provided on the outer periphery of the first cylindrical portion J2 of the cover holder J for housing the heat-sensitive driving member C and the upper cylindrical portion F4 of the wax holder F. The annular space R (having no opening 71A like a conventional heat retaining cover) is formed substantially closed, so that the temperature-sensitive driving member C can be effectively kept warm, and the hot restartability of the engine can be improved. I was able to do better than ever. In addition, the need to prepare special thermal insulation covers has been eliminated, which reduces the number of parts and the number of assembly steps, thereby reducing manufacturing costs and reducing the size of the automatic starter. Was also achieved. The base body A may be either the vaporizer main body 1 or the float chamber main body 4. Further, when forming the annular space portion R, an annular flange portion F5 extending laterally may be provided on the outer periphery of the wax holder F, and the second tubular portion J5 of the cover holder J may abut on the annular flange portion F5. According to this, before the automatic starter is mounted on the base body A, the annular space R
Is formed, it is easy to assemble the automatic starter to the base body A. That is, the automatic starter need only insert the lower cylindrical portion F3 of the wax holder F into the wax holder storage hole A1 of the base body A.

Further, by forming the cover holder J of a synthetic resin material, the heat retention in the annular space R can be further improved, and further, the weight of the entire apparatus can be reduced.
It is preferable from the viewpoint of cost reduction.

Further, the cover main body A is screwed into the cover holder J and the wax holder F, and the base body A is inserted through the mounting hole J8 formed in the mounting stay J7 of the cover holder J.
By screwing the screw Y toward the screw hole A3, the automatic starter can be fixed to the base body A at low cost without preparing a special mounting member.

[0030]

As described above, according to the apparatus for automatically starting a carburetor of the present invention, a temperature-sensitive device is provided between the first tubular portion of the cover holder, the upper tubular portion of the wax holder and the second tubular portion of the cover holder. A substantially sealed annular space along the longitudinal direction XX of the drive member is formed, so that the heat retention of the temperature-sensitive drive member can be improved more than before, and the hot restartability of the engine is greatly improved. As a result, it was not necessary to provide a special heat-insulating cover, so that the manufacturing cost could be reduced and the automatic starter could be made more compact. Further, since the lower end of the second cylindrical portion of the cover holder is in contact with the base body to form the annular space, the annular space can be formed extremely easily. According to the formation of the annular space, the lower end of the second cylindrical portion of the cover holder is brought into contact with the annular flange of the wax holder to form the annular space, and the annular space is formed in the sub-assembly state of the automatic starter. A space can be formed, which facilitates the assembly of the automatic starter to the base body. Further, when the cover holder is formed of a synthetic resin material, it is possible to further enhance the heat retention of the temperature-sensitive driving member by the annular space, and to achieve a reduction in the weight of the apparatus and a reduction in manufacturing cost. Furthermore, by fixing the cover holder to the base body via the mounting stay provided on the cover holder,
The automatic starter can be easily attached to the base body at a low cost.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a main part of an embodiment of an automatic starter for a vaporizer according to the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a conventional automatic starter for a vaporizer.

[Explanation of symbols]

 F Wax holder F1 Female thread J Cover holder J2 First cylinder part J4 Male thread J5 Second cylinder part C Temperature-sensitive drive member D Transmission member K Color R Annular space

Claims (5)

[Claims] A starting valve is displaced in synchronization with a temperature-sensitive driving member that is displaced in response to heat generated by a heater, and the displacement of the starting valve controls the opening of a starting air passage, a starting fuel passage, and a starting air-fuel mixture passage. An automatic starter for a carburetor in which a starting air-fuel mixture heading toward a starting air-fuel mixture passage is automatically controlled; a tubular wax holder F having both ends opened and a female screw F1 formed at an upper open end; It has a bottom cup shape, and has a heater 13 for heating the temperature-sensitive driving member C via a collar K at an upper bottom portion J1, terminals T1 and T2 electrically connected to the heater 13, and a male screw J4 formed at a lower end. A first cylindrical portion J2 and a second cylindrical portion J5 formed at the outer periphery of the first cylindrical portion J2 with a gap W and opening downward.
And a cover holder J integrally formed. The starter valve V engages a temperature-sensitive driving member C which is screwed with the male screw J4 of the cover holder J on the female screw F1 of the wax holder. The lower cylindrical portion F3 of the wax holder is accommodated in the wax holder accommodating hole A1 of the base body A, and the starting valve V is attached to the wax holder via the transmitting member D to be stopped. The first cylinder portion J2 of the cover holder, the upper cylinder portion F4 of the wax holder F, and the second cylinder portion J5 of the cover holder J are inserted and arranged in the start valve guide hole 61 connected to the storage hole A1. Longitudinal direction XX of the temperature-sensitive drive member C
An automatic starter for a carburetor, characterized in that a substantially closed annular space portion R is formed along the line. 2. The automatic starting device for a carburetor according to claim 1, wherein the lower end J6 of the second cylindrical portion J5 of the cover holder abuts on the base body A to form an annular space R. 3. The carburetor according to claim 1, wherein a lower end J6 of the second cylindrical portion J5 of the cover holder is in contact with an annular flange F5 of the wax holder F to form an annular space R. Automatic starter. 4. The automatic starting device for a carburetor according to claim 1, wherein said cover holder is formed of a synthetic resin material. 5. A stay J7 attached to the cover holder.
Are integrally formed, and the cover holder J is attached to the stay J7.
The automatic starting device for a carburetor according to claim 1, wherein the automatic starting device is screwed and fixed to the base body A via the base.