JPH0569359U - Sliding throttle valve type carburetor - Google Patents

Abstract

(57) [Summary] [Purpose] To make the sliding throttle valve slide smoothly with respect to the carburetor body, and to maintain the airtightness of the sliding throttle valve. [Structure] The sliding throttle valve 17 opens and closes an intake passage formed in the carburetor main body. A ring-shaped groove 23 is formed on the surface of the sliding throttle valve 17 on the engine side (the side that receives the negative pressure of the intake pipe), and the ring-shaped sealing member 24 is fitted into the ring-shaped groove 23.
The ring-shaped seal member 24 has a linear portion 24a at a portion corresponding to the lower portion of the intake passage, and also has linear portions 24b on both sides.
Have. Straight portions 23b that engage with the straight portions 24b are provided on both sides of the ring-shaped groove 23 of the sliding throttle valve 17. The straight portion 24a at the lower portion of the ring-shaped seal member 24 is larger than the bore diameter of the intake passage.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a carburetor for supplying and controlling an air-fuel mixture to an internal combustion engine, and more particularly to a carburetor having a sliding throttle valve.

[0002]

[Prior Art]

 The sliding throttle valve type carburetor is configured so that the sliding throttle valve is slidable in a direction orthogonal to the intake passage and opens and closes the intake passage. Conventionally, in order to prevent the sliding throttle valve from becoming difficult to slide due to clogging of dust or the like, for example, Japanese Patent Laid-Open No. 62-199953 proposes the following structure.

That is, in this sliding throttle valve type carburetor, rotary mechanisms such as bearings and rollers are attached to the sliding throttle valve to smooth the sliding of the sliding throttle valve, and the sliding throttle valve. The sliding throttle valve consists of two pieces, a main throttle valve and a sub-throttle valve, in order to ensure airtightness between the main throttle valve and the carburetor body. The sub-throttle valve is brought closer to the carburetor main body side by the negative pressure of the intake pipe, thereby maintaining the airtightness inside and outside the intake passage. In addition, it has been attempted to reduce the sliding resistance by applying suction negative pressure to the back surface of the auxiliary throttle valve to reduce the force of sucking the auxiliary throttle valve to the carburetor body side during deceleration of the engine. There is.

[0004]

[Problems to be solved by the device]

 However, according to the above configuration, the main throttle valve shows a smooth slide due to the rotating mechanism, but the sub throttle valve is strongly attracted to the carburetor main body by the negative pressure of the intake pipe, and the negative pressure of the intake pipe is reduced as in the case of deceleration. When the value is large, airtightness is good, but some throttle valve return force is required. Further, the sliding throttle valve is composed of two members, which complicates the structure. The present invention provides a sliding throttle valve type carburetor in which sliding of the sliding throttle valve with respect to the carburetor body is smooth and sufficient airtightness between the sliding throttle valve and the carburetor body is maintained. The purpose is to

[0005]

[Means for Solving the Problems]

 A sliding throttle valve type carburetor according to the present invention includes a carburetor main body having an intake passage formed therein, and a sliding throttle valve provided slidably in the carburetor main body and capable of opening and closing the intake passage. Fixed to the surface of the sliding throttle valve on the side that receives the negative pressure of the intake pipe, and when the sliding throttle valve is in the closed state, overlaps with the outer peripheral edge portion of the intake passage and adheres to the carburetor main body, and A ring-shaped seal member in which a straight line portion larger than the inner diameter of the intake passage is formed in a portion corresponding to the lower portion of the intake passage, and a means for preventing the ring-shaped seal member from rotating around its central axis. It is characterized by having and.

[0006]

【Example】

 The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a diagram showing a first embodiment of the present invention. In this figure, intake passages 13 and 14 are formed in the same axial direction in the carburetor main bodies 11 and 12 that are integrally connected. The intake passage 13 located on the left side of the drawing is an upstream passage communicating with the atmosphere, and the intake passage 14 located on the right side is a downstream passage communicating with the engine. That is, the intake pipe negative pressure generated by the engine acts on the intake passage 14 side. A plate-like sliding throttle valve 17 is provided in a space 16 extending in a direction that vertically crosses the intake passages 13 and 14 (a direction perpendicular to the paper surface). The sliding throttle valve 17 slides in the space 16 in conjunction with an accelerator mechanism (not shown) to open and close the intake passages 13 and 14.

Two parallel straight grooves 18 extending in a direction perpendicular to the plane of FIG. 1 are formed on the surface of the sliding throttle valve 17 on the intake passage 14 side, that is, on the side receiving the intake pipe negative pressure. A band-shaped shim 19 is provided in each linear groove 18. Two straight grooves 21 are formed on the end surface of the carburetor main body 12 so as to face the straight grooves 18, and each straight groove 21 is provided with a plurality of bearings 22.

A ring-shaped groove 23 is formed on the surface of the sliding throttle valve 17 on the intake passage 14 side and inside the two linear grooves 18, and a ring-shaped seal 23 is formed in the ring-shaped groove 23. The rule member 24 is fitted. That is, the ring-shaped seal member 24 moves integrally with the sliding throttle valve 17 in the sliding direction of the sliding throttle valve 17 (direction perpendicular to the paper surface), but with respect to the axial directions of the intake passages 13 and 14. In other words, it is displaceable with respect to the sliding throttle valve 17. Therefore, when the sliding throttle valve 17 closes the intake passages 13 and 14, the ring-shaped seal member 24 is superposed on the outer peripheral edge portions of the intake passages 13 and 14, and the intake pipe negative pressure generated in the intake passage 14 is generated. Upon receipt, it comes into close contact with the end surface of the carburetor body 12.

The ring-shaped seal member 24 is molded from a material having excellent operability and durability. Resins (for example, fluorine-based), or fluorine-coated ceramics or metals are suitable as materials satisfying these conditions.

FIG. 2 is an exploded view of the sliding throttle valve 17 and the ring-shaped seal member 24. On the inner peripheral side of the ring-shaped groove 23 formed on the surface of the sliding throttle valve 17, a disc-shaped portion 25 that fits into the circular hole 24e of the ring-shaped seal member 24 is formed. The outer shape of the ring-shaped groove 23 is not a perfect circle, but a straight portion 23a is formed in a portion corresponding to the bottom surface 17a of the sliding throttle valve 17, that is, a portion corresponding to the lower portion of the suction passage 14. Further, linear portions 23b perpendicular to the bottom surface 17a are formed on both sides of the ring-shaped groove 23. The ring-shaped sealing member 24 has substantially the same shape as the ring-shaped groove 23, and has a linear portion 24a corresponding to the bottom surface 17a of the sliding throttle valve 17 and a linear portion 24b corresponding to both side portions of the ring-shaped groove 23. Have. That is, a corner portion 24c forming a right angle is formed at a portion where the straight line portions 24a and 24b intersect.

FIG. 3 shows a portion of the ring-shaped seal member 24 facing the inside of the intake passage 14 and a disc-shaped portion 25 of the sliding throttle valve 17. In this figure, a donut-shaped portion A shown by hatching is a portion facing the inside of the intake passage 14. That is, the outer peripheral edge C of the donut-shaped portion A matches the inner wall surface 14a (FIG. 1) of the intake passage 14, and therefore, the donut-shaped portion A has a ring-shaped seal member 24 with a negative pressure in the intake pipe. It is a pressure receiving surface that acts on. The disk-shaped portion 25 is a pressure receiving surface on which the intake pipe negative pressure acts on the sliding throttle valve 17.

As can be seen from FIG. 3, the width B of the straight portion 24 a formed in the lower portion of the ring-shaped seal member 24 is larger than the inner diameter of the intake passage 14, that is, the bore diameter D.

The suction force of the ring-shaped seal member 24 with respect to the end surface of the carburetor main body 12, that is, the suction force acting on the ring-shaped seal member 24 toward the intake passage 14 is the pressure-receiving area of the ring-shaped seal member 24. It is adjusted by setting the (area of the donut-shaped portion A) to an appropriate size. As a result, the desired sealability can be obtained with the minimum required suction force.

The sliding throttle valve 17 receives the negative pressure of the intake pipe through the disk-shaped portion 25 and is sucked toward the intake passage 14 side, but is supported by the bearing 22 and thus received from the end surface of the carburetor main body 12. Sliding resistance is small. Therefore, the opening / closing operation of the sliding throttle valve 17 is very smooth.

As described above, in the present embodiment, the opening / closing operation of the sliding throttle valve 17 is not substantially affected by the intake pipe negative pressure received by the sliding throttle valve 17, and the sliding throttle due to this intake pipe negative pressure is used. The sealing property of the valve 17 is obtained by the ring-shaped sealing member 24. Since the pressure-receiving area of the ring-shaped seal member 24 is smaller than the cross-sectional area of the bore of the intake pipe 14, the ring-shaped seal member 24 is protected even when the intake pipe negative pressure is large such as during deceleration. An excessive suction force does not act, and the sliding throttle valve 17 can be opened with a small force while maintaining an appropriate airtightness.

Further, in the present embodiment, the sliding throttle valve 17 is not composed of two members (main throttle valve and sub-throttle valve) as in the prior art, but is formed of one member. The tightness is obtained by the ring-shaped sealing member 24 fixed to the sliding throttle valve 17. Therefore, the structure of the sliding throttle valve 17 is simplified, and the cost of the carburetor can be reduced.

Further, in this embodiment, since the ring-shaped seal member 24 is fixed to the sliding throttle valve 17, the ring-shaped seal member 24 is placed in the intake passages 13 and 14 when the sliding throttle valve 17 is open. It is not exposed and therefore there is no risk of fuel entering the ring groove 18.

Further, in this embodiment, the linear portions 24b on both sides of the ring-shaped sealing member 24 are engaged with the linear portions 23b formed on both sides of the ring-shaped groove 23, and the ring-shaped sealing member 24 is , Never rotate around its central axis. If the ring-shaped seal member 24 is rotatable, the corner portion 24c of the ring-shaped seal member 24 faces the intake passage 14 when the sliding throttle valve 17 is opened and closed. There is a risk that it will be caught on the inner wall surface of 14 and interfere with the opening / closing operation of the sliding throttle valve 17. However, in this embodiment, since the width B of the straight portion 24a of the ring-shaped seal member 24 is larger than the bore diameter D of the suction passage 14 and the ring-shaped seal member 24 does not rotate, the corner portion 24c is located in the intake passage 14. It does not get caught on the inner wall. Therefore, a stable opening / closing operation of the sliding throttle valve 17 can be obtained.

FIG. 4 shows a second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals, and only different parts will be described. A spring hole 31 is formed in the bottom of the ring-shaped groove 23 formed in the sliding throttle valve 17, and a spring 32 is arranged in the spring hole 31. The spring 32 urges the ring-shaped seal member 24 toward the carburetor body 12 side. Other configurations are the same as those in the first embodiment.

The spring 32 may be a coil spring, but an appropriate elastic member can be applied.

According to the configuration of the second embodiment, the same effect as that of the first embodiment can be obtained, but the following effect can also be obtained. That is, the sealing property of the ring-shaped seal member 24 is obtained not only by the negative pressure of the intake pipe but also by the elastic force of the spring 32. Therefore, the pressure receiving area of the ring-shaped seal member 24 can be made smaller than that in the first embodiment. For example, the inner diameter of the ring-shaped seal member 24 is made the same as the bore diameter of the intake passage 14 to receive the pressure in the closed state. It is also possible to make the area zero.

FIG. 5 shows a ring-shaped seal member 41 of the third embodiment. This ring-shaped seal member 41 has a linear portion 41a in the lower portion, as in the first embodiment, and the width B of this linear portion 41a depends on the bore diameter D of the intake passage 14 (see FIG. 3). Is also big. Further, on both sides of the ring-shaped seal member 41, straight line portions 41b which are in contact with a circle forming the outer shape of the ring-shaped seal member 41 are formed. Unlike the first embodiment, these straight portions 41b are not perpendicular to the lower straight portion 41a, and the corner portions 41c form an obtuse angle. With the configuration of the third embodiment, the same effect as that of the first embodiment can be obtained.

FIG. 6 shows a ring-shaped seal member 42 of the fourth embodiment. This ring-shaped sealing member 42 also has a straight portion 42a having a width B larger than the bore diameter D of the intake passage 14 in the lower portion, as in the third embodiment. However, the straight line portions 42b formed on both sides of the ring-shaped seal member 42 are not in contact with the circle forming the outer shape of the ring-shaped seal member 42, unlike the third embodiment. With the configuration of the fourth embodiment, the same effects as those of the first and third embodiments can be obtained.

FIG. 7 shows a ring-shaped seal member 43 of the fifth embodiment. This ring-shaped seal member 43 has a straight portion 43a larger than the bore diameter D of the intake passage 14 in the lower portion, as in each of the above embodiments, but is formed on both sides of the ring-shaped seal member 43. The two straight portions 43b are left-right asymmetrical, unlike the respective embodiments. With the configuration of the fifth embodiment, the same effects as those of the above embodiments can be obtained.

FIG. 8 shows a ring-shaped seal member 44 and a sliding throttle valve 45 of the sixth embodiment. The ring-shaped sealing member 44 is formed by forming a circular hole 44e at the center of a rectangular plate-shaped member, and has a symmetrical shape in the left and right and in the up and down. That is, the linear portion 44a at the lower portion and the linear portions 44b at both sides of the ring-shaped sealing member 44 respectively correspond to one side of the rectangle. The ring-shaped groove 46 of the sliding throttle valve 45 has the same shape as the ring-shaped seal member 44. That is, the sliding throttle valve 45 has the protrusions 48 that linearly extend in the vertical direction on both sides of the disc-shaped portion 47. With the structure of the sixth embodiment, the same effects as those of the above-described embodiments can be obtained, but the ring-shaped seal member 44 can be incorporated into the sliding throttle valve 45 without considering the vertical direction. As a result, the assemblability is improved.

[0026]

[Effect of the device]

 As described above, according to the present invention, the sliding movement of the sliding throttle valve with respect to the carburetor body is smooth, and sufficient airtightness between the sliding throttle valve and the carburetor body is maintained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a sliding throttle valve type carburetor according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an exploded view of a sliding throttle valve and a ring-shaped seal member.

FIG. 3 is a view showing a portion of the ring-shaped seal member facing the intake passage and a disc-shaped portion of the sliding throttle valve.

FIG. 4 is a sectional view showing a sliding throttle valve type carburetor according to a second embodiment of the present invention.

FIG. 5 is a front view showing a ring-shaped seal member of a third embodiment.

FIG. 6 is a front view showing a ring-shaped seal member of a fourth embodiment.

FIG. 7 is a front view showing a ring-shaped seal member of a fifth embodiment.

FIG. 8 is an exploded perspective view showing a sliding throttle valve and a ring-shaped seal member of a sixth embodiment.

[Explanation of symbols]

 11, 12 Vaporizer body 13, 14 Intake passage 17, 45 Sliding throttle valve 23 Ring-shaped groove 24, 41, 42, 43, 44 Ring-shaped seal member

Claims (2)

[Scope of utility model registration request] 1. A carburetor main body having an intake passage, a sliding throttle valve slidably provided in the carburetor main body and capable of opening and closing the intake passage, and an intake pipe of the sliding throttle valve. It is fixed to the surface on the side receiving negative pressure, and when the sliding throttle valve is in the closed state, it is superposed on the outer peripheral edge portion of the intake passage and adheres to the carburetor main body, and at the portion corresponding to the lower portion of the intake passage. And a ring-shaped seal member having a linear portion larger than the inner diameter of the intake passage, and means for preventing the ring-shaped seal member from rotating around its central axis. Dynamic throttle valve type carburetor. 2. The sliding throttle valve type carburetor according to claim 1, wherein the ring-shaped sealing member is fitted in a ring-shaped groove formed on the surface of the sliding throttle valve.