CN1743655A

CN1743655A - Vaporizer acceleration device

Info

Publication number: CN1743655A
Application number: CN 200510093696
Authority: CN
Inventors: 吴武夫
Original assignee: Keihin Dock Co Ltd
Current assignee: Keihin Dock Co Ltd
Priority date: 2004-09-01
Filing date: 2005-09-01
Publication date: 2006-03-08
Anticipated expiration: 2025-09-01
Also published as: TWI311173B; CN100520038C; JP4074944B2; JP2006070787A; TW200615448A

Abstract

To provide an accelerator which materializes inexpensive manufacturing cost and easy change in discharge start timing of accelerating fuel in an extremely short time. A plurality of pin engaging holes 30a, 30b, 30c are circumferentially drilled in a throttle drum 30. A spring collar 31 is equipped with a cylinder part 31a, a throttle valve shaft inserting hole 31c penetrating to the bottom 31b, a collar part 31d, an engaging pin 31e projecting to one side surface 31d1 of the collar part 31d and a lever press pin 31f projecting to the other side surface 31d2 of the collar part 31d. A throttle valve shaft 5 is inserted into and arranged in the throttle valve shaft inserting hole 31c of the spring collar 31, which is pressed onto a side surface 30d of the throttle drum 30 by the throttle valve return spring S. The engaging pin 31e is selected by one of a plurality of pin engaging holes to be engaged therewith. The spring collar 31 and the throttle drum 30 are synchronously rotated. The lever press pin 31f is arranged so as to face the other end of a link lever 13.

Description

Carburetor accelerator

Technical Field

The present invention relates to a carburetor for controlling the amount and concentration of a mixture gas supplied to an engine, and more particularly to a carburetor acceleration device for injecting and supplying an acceleration fuel to an engine during a rapid acceleration operation of the engine.

Background

Fig. 4 shows a conventional carburetor accelerator. To explain with reference to the figure, 1 denotes a duct body provided with an intake duct 2 penetrating the inside, a float chamber body 3 is provided below the body 1, and a float chamber 4 in which a certain amount of fuel is stored is formed by the body 1 and the float chamber body 3. A throttle shaft 5 that traverses the intake air passage 2 is rotatably supported by the body 1, and the intake air passage 2 is opened and closed by a throttle valve 6 screwed to the throttle shaft 5. The throttle drum 7 is fixed to an end portion of the throttle shaft 5 protruding from the body 1, and the throttle drum 7 is connected to an accelerator pedal clamp (the close valve cable, the open valve cable, and the accelerator pedal clamp are not shown) by closing the valve cable and opening the valve cable. Then, one end of the spiral throttle valve return spring S is engaged with the throttle drum 7, and the return spring S constantly applies an elastic force to the throttle drum 7 in a direction to close the valve (the other end of the return spring S is engaged with the body main body 1). With this configuration, when the operator operates the valve-opening cable, the throttle drum 7 is rotated in the throttle-opening direction (clockwise direction in the drawing) against the elastic force of the return spring S, thereby causing the throttle valve 6 to open the intake passage 2. On the other hand, when the closing valve cable is operated by the operator, the throttle drum 7 is rotated in the throttle closing direction (counterclockwise in the drawing) by the operating force of the closing valve cable and the elastic force of the return spring S, whereby the throttle 6 closes the intake passage 2. Reference numeral 8 denotes an acceleration pump chamber having openings for an acceleration fuel suction passage 9 and an acceleration fuel discharge passage 10 inside, and the upper stage side of the acceleration fuel suction passage 9 communicates with the fuel in the float chamber 4, while the lower stage side of the acceleration fuel discharge passage 10 opens in the intake air passage 2 through a pump nozzle, not shown. The pump chamber volume of the acceleration pump chamber 8 is increased and decreased by a piston 11 provided in the acceleration pump chamber 8 to be movable forward and backward. The piston 11 is slidably provided in the cylinder bore 12, and a tip end portion of the piston 11 is provided so as to face the acceleration pump chamber 8. When the piston 11 moves downward in the drawing, the pump chamber volume of the acceleration pump chamber 8 is reduced and the pressure is increased, and the fuel in the acceleration pump chamber 8 is injected and supplied to the intake air passage 2 through the acceleration fuel injection passage 10 and a pump nozzle, not shown. On the other hand, when the piston 11 moves upward, the pump chamber volume of the accelerator pump chamber 8 is increased and the pressure is decreased, and the fuel in the float chamber 4 is sucked into the accelerator pump chamber 8 through the accelerator fuel suction passage 9 and is discharged as the next accelerated fuel discharge. Further, 12 is a pump spring provided in the acceleration pump chamber 8 in a contracted state, and the pump spring applies an upward elastic force to the piston 11. The reference numeral 13 denotes a link for operating the piston 11 in response to opening and closing of the throttle valve 6, and an intermediate portion of the link 13 is supported by the shaft 1a so as to be swingable. One end 13a of the connecting rod 13 is disposed in abutment with the upper end 11a of the piston 11, and the other end 13b of the connecting rod 13 is disposed facing the pin 14 erected on the throttle drum 7. The link 13 is biased (counterclockwise in the drawing) by a link spring (not shown) having one end 13a thereof abutting against the upper end 11a of the piston 11, and therefore the spring force of the link spring is set to be smaller than the spring force of the pump spring 12. Further, since the other end 13b of the link 13 is disposed in contact with the pin 14 or with a gap therebetween at the time of the idle opening degree of the throttle valve 6, the setting is selected when the start of the accelerated fuel injection is determined.

According to such a conventional accelerator apparatus, when the throttle valve 6 is rapidly opened in accordance with rapid rotation of the throttle drum 7, the pin 14 erected on the throttle drum 7 abuts on the other end 13b of the link 13, and the link 13 is rapidly swung. That is, the link 13 rapidly swings counterclockwise in the drawing in synchronization with the rotation of the throttle valve 7. When the connecting rod 13 rapidly swings, the one end 13a of the connecting rod 13 rapidly pushes and moves the piston 11 downward by the upper end 11a of the piston 11, so that the pump chamber volume of the acceleration pump chamber 8 rapidly decreases by the entry of the piston 11, and the pressure in the acceleration pump chamber increases, whereby the fuel stored in the acceleration pump chamber 8 is injected and supplied into the intake air passage 2 through the acceleration fuel injection passage 10 and a pump nozzle, not shown. By this fuel injection, the mixture can be controlled to be temporarily thinned when the throttle valve 6 is opened sharply, and the engine can be operated with good acceleration. When the throttle valve 6 is changed from the intermediate-and high-opening-degree open state to the low-opening-degree open state and closed, the throttle drum 7 rotates counterclockwise in the drawing, so the pin 14 does not press the one end 13b of the link 13, the piston 11 is returned upward by the elastic force of the pump spring 12, and the link 13 is pressed by the piston 11, swings clockwise, and is returned to the initial position.

Disclosure of Invention

In such a conventional accelerator apparatus, when the injection start timing of the acceleration fuel with respect to the opening degree of the throttle valve 6 needs to be changed in accordance with the characteristics of the engine, the riding comfort, and the like, the following change is required:

(1) change of position of upper end 11a of piston 11 (change of total length of piston)

(2) The change of the caulking position of the throttle drum 7 with respect to the throttle shaft 5.

(3) Modification of the link 13.

According to the above modification, a new mold is required to be processed particularly in manufacturing the throttle drum and the connecting rod, which results in an increase in manufacturing cost. Further, the number of types of pistons, throttle drums, and connecting rods increases, which complicates the parts management work and makes it difficult to efficiently produce the parts. The present invention has been made in view of the above problems, and an object thereof is to provide a carburetor acceleration device that can easily match the start timing of accelerated fuel injection with the characteristics of an engine in a very short time without increasing the manufacturing cost.

In order to achieve the above object, a carburetor accelerator apparatus of the present invention includes: a throttle drum fixed to an end of a throttle shaft rotatably supported by the body main body and biased in a throttle closing direction by a throttle return spring; a piston that increases and decreases a pump chamber volume of an acceleration pump chamber having openings of an acceleration fuel suction passage and an acceleration fuel discharge passage; and a connecting rod, which can be supported in a freely swinging manner, wherein one end of the connecting rod is butted with the piston, and the other end of the connecting rod is arranged opposite to a pin vertically arranged on the throttle drum; among them, the 1 st feature of the present invention is: a plurality of pin engaging holes are formed through the throttle drum fixedly provided at the end of the throttle shaft in the circumferential direction around the axis of the throttle shaft; on the other hand, a circlip provided on the outer periphery of the throttle shaft includes: a cylindrical portion formed in a bottomed cup shape, a throttle shaft insertion hole provided in a bottom portion of the cylindrical portion so as to penetrate therethrough, an annular flange portion extending outward from an upper end of the cylindrical portion, an engagement pin protruding from one side surface of the flange portion, and a lever push pin protruding from the other side surface of the flange portion, wherein the throttle shaft is rotatably inserted into the throttle shaft insertion hole provided in the circlip, and a spiral throttle return spring is provided on an outer periphery of the cylindrical portion in a contracted manner; the flange portion of the circlip is pressed against the side surface of the throttle drum by the throttle return spring, the engaging pin is engaged with the pin engaging hole of the throttle drum, and the lever pressing pin is disposed to face the other end of the connecting rod.

The present invention has the feature 2 in addition to the feature 1 described above, that is, the snap ring is formed of a synthetic resin material, and the engaging pin and the lever pressing pin are integrally formed.

(effect of the invention)

According to the invention according to the 1 st feature, the throttle shaft is inserted into the throttle shaft insertion hole of the circlip, the flange portion of the circlip is pressed against the side surface of the throttle drum by the elastic force of the throttle return spring, and the engagement pin of the circlip engages with one of the plurality of pin engagement holes provided through the throttle drum. Moreover, the circlip and the throttle drum can be engaged together along the rotation direction of the throttle shaft, and then the throttle drum rotates, so that the circlip and the throttle drum rotate synchronously. On the other hand, the rod pressing pin of the circlip is provided facing the other end of the connecting rod. Therefore, when the throttle drum rotates, the spring collar rotates in synchronization with the throttle drum, and the lever pressing pin presses the other side of the connecting rod to swing the connecting rod according to the rotation of the throttle drum, and one end of the connecting rod presses the piston to compress the fuel in the acceleration pump chamber, so that the acceleration fuel can be injected and supplied to the intake passage through the acceleration fuel injection passage and the pump nozzle, and the engine can be accelerated well. According to the present invention, the engagement pin of the circlip is engaged with any one of the plurality of pin engagement holes provided through the throttle drum, whereby the ejection start timing for ejecting the acceleration fuel from the acceleration device can be freely selected. In this way, since the selection can be achieved by simply rotating the spring collar and selectively engaging the engagement pin with the pin engagement hole, a new component is not required, and such an engagement operation can be easily performed in a short time. Further, the spring collar is pressed against the throttle drum by the elastic force of the throttle return spring, and the spring collar and the throttle drum are fixed without welding or the like, so that the ejection start timing can be changed very easily after one ejection start timing is determined.

Further, according to the invention of claim 2, since the circlip having the engaging pin and the lever pushing pin is integrally formed of a synthetic resin material, the manufacturing cost of the circlip having the pin can be reduced.

Drawings

FIG. 1 is a side view including a cross-sectional view showing one embodiment of a carburetor acceleration apparatus of the present invention;

FIG. 2 is a longitudinal sectional view of a key portion along the line A-A of FIG. 1;

FIG. 3 is a perspective view of the circlip used in FIG. 2;

fig. 4 is a side view including a cross-sectional view showing a conventional carburetor acceleration device.

Description of the symbols

5 throttle shaft

13 connecting rod

13a one end of the connecting rod

13b connecting rod another end

30 throttle drum

30a, 30b, 30c pin engaging holes

Side of 30d throttle drum

31 spring retainer ring

31a cylinder part

31b bottom part

31c throttle shaft insertion hole

31d flange part

31e engaging pin

31f lever pressing pin

Detailed Description

The vaporizer accelerating device of the present invention will be explained below with reference to fig. 1 and 2. In addition, the same structure as the related art is denoted by the same reference numeral, and a description thereof will be omitted. The throttle drum is different from the prior art in that a spring collar is prepared. The throttle drum is fixed to an end of the throttle shaft 5 by caulking or the like as in the conventional art, and a plurality of

pin engagement holes

30a, 30b, and 30c are provided through the throttle drum 30 on a circumference of a radius R around an axis X-X of the throttle shaft 5. For convenience, they are referred to as a1 st pin engaging hole 30a, a 2 nd pin engaging hole 30b, and a 3 rd pin engaging hole 30c, respectively, from the top to the bottom.

The circlip 31 is provided between the outer periphery of the throttle shaft 5 and the inner periphery of the helical throttle return spring S, and has the following configuration. The throttle shaft 31a is a bottomed cup-shaped cylinder portion, and the throttle shaft 5 is inserted through a throttle shaft insertion hole 31c rotatably inserted into a bottom portion 31b of the cylinder portion 31 a. Further, since the annular flange portion 31d extending outward is formed at the upper end of the tube portion 31a, the engaging pin 31e engaging with the

pin engaging holes

30a, 30b, and 30c provided in the throttle drum 30 is formed projecting from one side surface 31d1 of the flange portion 31d, and the lever pressing pin 31f is formed projecting from the other side surface 31d2 of the flange portion 31 d. The center of the engagement pin is set from the center of the throttle shaft insertion hole 31c to the radius R identical to the radius R of the pin engagement hole 30 a.

As described later, the circlip 31 is attached to the throttle shaft 5 and the throttle drum 30. This is described below in conjunction with fig. 2 (fig. 2 is a longitudinal sectional view of a key portion along the line of fig. 1A-a). The throttle shaft 5 is rotatably provided in a throttle shaft hole 1b penetrating a bearing protrusion 1a of the body 1, and the circlip 31 is provided between a right side surface 30d of the throttle drum 30 fixed to an end of the throttle shaft 5 and a left end surface 1a1 of the bearing protrusion 1 a. The throttle shaft 5 is rotatably inserted into the throttle insertion hole 31c of the circlip 31, and the spiral throttle return spring S is disposed so as to be contracted around the outer periphery of the cylindrical portion 31a and between the other side surface 31d2 of the flange portion 31d and the body 1. In fig. 2, the right hook (not shown) of the throttle return spring S is hooked on the throttle body 1, the left hook (not shown) is locked to the throttle drum 30, and the throttle return spring S applies a rotational force in a counterclockwise direction in fig. 1 (that is, a closing direction of the throttle valve 6) to the throttle shaft 5 including the throttle drum 30. When the throttle return spring S is disposed between the other side surface 31d2 of the flange portion 31d and the body main body 1, the throttle return spring S is contracted in the spring length direction (corresponding to the length direction of the throttle shaft 5), and the one side surface 31d1 of the flange portion 31d of the circlip 31 is pressed and fixed against the right side surface 30d of the throttle drum 30, and at this time, the engagement pin 31e of the circlip 31 is engaged with the 1 st pin engagement hole 30a of the throttle drum 30. Therefore, the circlip 31 and the throttle drum 30 are synchronously rotated in the rotational direction by the engagement of the pin 31e and the 1 st pin engagement hole 30 a. Further, since the circlip 31 is always elastically pressed against the throttle drum 30 by the throttle return spring S, the engagement pin 31e does not come out of the 1 st pin engagement hole 30 a. On the other hand, as described above, in the state where the circlip 31 is engaged with and disposed on the throttle drum 30, the lever pressing pin 31f of the circlip 31 is disposed to face the other end 13b of the link 13.

That is, in a state where the circlip 31 is provided on the outer periphery of the throttle shaft 5, the right side surface 30d of the throttle drum 30, and the left end surface 1a1 of the bearing protrusion 1a, the circlip 31 is connected to the throttle drum 30 in the rotational direction, and the lever pressing pin 31f disposed on the circlip 31 is provided facing the other end 13b of the link 13.

Thus, at the time of engine rapid acceleration operation, acceleration fuel is supplied according to the following procedure. For example, when the throttle valve 6 is at the idle opening, the lever pressing pin 31f is provided in contact with the other end 13b of the link 13. In such an idle opening state, when the throttle drum 30 is rapidly opened by the operator, the throttle drum 30 rotates clockwise in fig. 1, the rotation of the throttle drum 30 is transmitted to the circlip 31 via the pin engaging hole 30a and the engaging pin 30e, and the circlip 31 rotates clockwise in synchronization with the throttle drum 30. When the circlip 31 is rotated clockwise, the lever pressing pin 31f moves the other end 13b of the link 13 upward, and the link 13 swings counterclockwise in fig. 1. When the connecting rod 13 swings counterclockwise in this way, the one end 13a of the connecting rod 13 presses the upper end 11a of the piston 11, and the piston 11 moves downward against the elastic force of the pump spring 12. The piston 11 moves downward to reduce the pump chamber volume in the acceleration pump chamber 8, rapidly raise the fuel pressure stored in the acceleration pump chamber 8, and inject the fuel after the pressure rise into the intake air passage 2 through the acceleration fuel discharge passage 10, thereby making it possible to perform the engine acceleration operation due to the rapid opening of the throttle valve 6 in a satisfactory manner. On the other hand, when the throttle valve 6 is moved from the open state to the closing direction of the idle opening, the lever pressing pin 31f is pivotally moved in the direction away from the other end 13b of the link 13, and therefore, a mechanical pressing force to the link 13 cannot be generated from the lever pressing pin 31 f.

As described above, in the rapid acceleration operation from the idle opening of the throttle valve 6, the acceleration fuel is injected and supplied, and here, the case of injection supply (that is, the acceleration fuel injection start timing is delayed) in which the closed idle opening slightly opened from the idle opening is set as the acceleration fuel injection start timing will be described. At this time, the engagement pin 31e is engaged with the 3 rd pin engagement hole 30c of the throttle drum 30. Therefore, at the time of the idle opening degree of the throttle valve 6, a clearance L is formed between the lever pressing pin 31f and the other end 13b of the link 13. The gap is indicated by a one-dot chain line in fig. 1. As described above, after the throttle valve 6 is opened by the clearance L, the lever pressing pin 31f abuts against the other end 13b of the link 13, and the link 13 is swung by opening the throttle valve 6 thereafter to eject the accelerated fuel, whereby the timing of ejecting the accelerated fuel can be shifted.

As described above, according to the carburetor acceleration device according to the present invention, the spring collar 31 is simply rotated with respect to the throttle shaft 5, and one of the plurality of

pin engagement holes

30a, 30b, and 30c of the throttle drum 30 is selected to be engaged with the engagement pin 31e of the spring collar 31, whereby the acceleration fuel injection start timing can be freely set. Further, since this is realized by the throttle drum 30 having the

pin engaging holes

30a, 30b, and 30c and the circlip 31, when any change is made to the ejection start timing, there is no need to change the set throttle drum and circlip. When the ejection start timing is to be changed after the ejection start timing is set, the spring retainer 31 is separated from the right side surface 30d of the throttle drum 30 against the longitudinal elastic force of the throttle return spring S, the engagement pin 31e is disengaged from the pin engagement hole, and then the spring retainer 31 is rotated to engage the engagement pin 31e with another pin engagement hole, so that the change can be performed very easily and in a short time. This change can be achieved by forming the snap ring 31 separately from the throttle drum 30, and the snap ring 31 is engaged by being elastically pressed by the throttle return spring S.

In addition, when the circlip 31 is formed by ejecting a synthetic resin material, and the engaging pin 31e and the lever pressing pin 31f are integrally formed, the manufacturing cost of the circlip 31 having these pins can be reduced.

Further, a roller may be provided on the outer periphery of the lever pressing pin 31f, and the lever pressing pin 31f may be disposed in contact with the other end 13b of the link 13 by the roller. The rollers are not shown. In addition, instead of the piston 11 that increases or decreases the pump chamber volume of the acceleration pump chamber 8, a diaphragm may be used, and in this case, the upper end of the rod portion extending upward from the diaphragm may be disposed in abutment with the one end 13a of the connecting rod 13.

Claims

1. A carburetor accelerator apparatus, comprising: a throttle drum fixed to an end of a throttle shaft rotatably supported by the body main body and biased in a throttle closing direction by a throttle return spring;

a piston that increases and decreases a pump chamber volume of an acceleration pump chamber having an acceleration fuel suction passage and an acceleration fuel discharge opening; and a connecting rod which is supported in a freely swinging manner, one end of which is butted with the piston, and the other end surface of which is arranged opposite to a pin vertically arranged on the throttle drum; wherein,

the method is characterized in that: a throttle drum (30) fixedly provided at an end portion of a throttle shaft is provided with a plurality of pin engagement holes (30a, 30b, 30c) penetrating in a circumferential direction around an axis X-X of the throttle shaft (5), and a circlip (31) provided on an outer periphery of the throttle shaft (5) has: a cup-shaped cylinder part (31a) with a bottom, a throttle shaft insertion hole (31c) arranged on the bottom part (31b) of the cylinder part (31a) in a penetrating way, an annular flange part (31d) extending outwards from the upper end of the cylinder part,

An engaging pin (31d) protruding from one side surface (31d 1) of the flange (31d),

And a lever pushing pin (31e) protruding from the other side surface (31d2) of the flange portion (31d),

a throttle shaft (5) is rotatably inserted into a throttle shaft insertion hole (31c) provided in the circlip, and a spiral throttle return spring (S) is provided so as to be contracted on the outer periphery of the cylindrical portion (31 a); a flange part (31d) of a circlip (31) is pressed and arranged on a side surface (30d) of a throttle drum (30) through the throttle return spring, an engaging pin (31e) is engaged and arranged in a pin engaging hole of the throttle drum (30), and a rod pressing pin (31f) is arranged opposite to the other end of the connecting rod.

2. The vaporizer accelerating device of claim 1, wherein: the spring collar is formed of a synthetic resin material, and the engaging pin (31e) and the lever pressing pin (31f) are formed integrally.