JP3543979B2 - Sliding valve carburetor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for manufacturing a carburetor for a motorcycle or the like, and more particularly to a method for manufacturing a sliding valve type carburetor in which a flow passage area of an intake passage is changed by a sliding valve entering and leaving an intake passage.
[0002]
[Prior art]
Conventionally, an intake passage through which air taken in from outside via an air funnel or the like flows inside a carburetor body of a sliding valve carburetor, and a sliding cylinder communicating with the intake passage at a predetermined angle. A sliding valve is known in which a sliding valve slides in and out of the sliding cylinder to enter and exit the intake passage, thereby changing the flow passage area of the intake passage. Further, in order to smoothly move the sliding valve into and out of the intake passage, a sliding cylinder or a sliding valve provided with a roller or a bearing for reducing the sliding resistance is also known.
[0003]
The sliding cylinder must be formed with the same exact dimensions and finish as the sliding valve so that air does not leak from the sliding contact with the sliding valve when the intake passage is fully closed. Must. As a method of manufacturing a carburetor having such a sliding cylinder, for example, a carburetor body formed by casting is broached at a predetermined angle in an intake passage to form a slide of a desired shape. There is a method of assembling a member that forms a sliding cylinder to a tubular member that forms a moving cylinder or an intake passage.
[0004]
[Problems to be solved by the invention]
However, since the method of broaching the sliding cylinder is a method of cutting through the carburetor body at a predetermined angle with respect to the intake passage provided in the carburetor body, the lower end of the sliding cylinder is a carburetor. Therefore, the lower end must be closed by another member, and the structure including the closing member tends to be complicated. In addition, since the broaching itself requires a large number of tools, the processing equipment cost is high, the processing time is long, and it cannot be said that it is advantageous in terms of cost.
[0005]
On the other hand, in the method of assembling a plurality of members to form the vaporizer main body, in assembling the members, it is necessary to accurately finish the dimensions of the assembly portion of each member, and to secure the strength of each member and a roller. In terms of equipment, assembled vaporizers tend to be complex and bulky, which is disadvantageous in terms of cost.
[0006]
The present invention has been made in view of the above problems, and reduces the number of parts of a sliding valve carburetor, easily manufactures the sliding valve carburetor, and reduces the manufacturing cost. The purpose is to obtain a manufacturing method that can be performed.
[0007]
[Means for Solving the Problems]
A sliding valve carburetor according to the present invention includes a carburetor body having a sliding cylinder communicating with an intake passage, a slidably supported inside the sliding cylinder, and a passage area of the intake passage protruding from the intake passage. A sliding valve for changing the pressure of the sliding valve, wherein grooves along the sliding direction are formed on both sides of the sliding valve, and the grooves are fitted into the grooves on both sides of the sliding cylinder. A bearing plate provided with a plurality of bearings for reducing sliding resistance between the sliding valve and the sliding cylinder is mounted and fixed.
[0008]
【Example】
Hereinafter, the present invention will be described with reference to the illustrated embodiments.
FIGS. 1 to 3 schematically show the configuration of a sliding valve type carburetor manufactured by a manufacturing method according to a first embodiment of the present invention.
[0009]
In FIG. 1, an intake passage 12 is formed along an axis A inside a carburetor body 11. A slide valve 13 that can be displaced in a direction orthogonal to the axis A is provided in the intake passage 12. The sliding valve 13 is slidably supported in a sliding cylinder 14 formed in the carburetor body 11 and changes the flow passage area of the intake passage 12 by being displaced in the vertical direction in FIG. A float chamber 15 is provided below the sliding valve 13, and the fuel stored in the float chamber 15 is guided to the intake passage 12 through the fuel passage 16. The flow rate of the fuel passing through the fuel passage 16 is adjusted by the degree of insertion of the jet needle 17 fixed below the slide valve 13 and inserted into the fuel passage 16.
[0010]
A throttle shaft 18 interlocking with a throttle lever (not shown) is rotatably supported on an upper portion of the carburetor body 11, and a connection lever 19 swingable about the throttle shaft 18 is fixed to the throttle shaft 18. The sliding valve 13 is connected to the tip of the connecting lever 19, and the sliding of the connecting lever 19 causes the sliding valve 13 to move up and down in the sliding cylinder 14. A cover 20 is attached to an upper portion of a portion where the throttle shaft 18 and the connecting lever 19 are stored. An air funnel 21 is fixed to an upstream end of the intake passage 12. The air funnel 21 is formed in a trumpet shape, and takes in air into the intake passage 12 from outside.
[0011]
FIG. 2 is a top view of the carburetor body 11 with the cover 20 and the air funnel 21 removed, and FIGS. 3A and 3B are disassembled and assembled states of the carburetor body 11 (part). FIG.
[0012]
In FIG. 2, a plurality of roller bearings 22 are provided on both sides 14 a of the sliding cylinder 14 located in the vertical direction to contact the side of the sliding valve 13 to smoothly slide the sliding valve 13. The roller bearing 22 is preferably formed of a synthetic resin material in order to reduce noise, and is rotatably supported via a pin 24 on one piece of a bearing plate 23 as shown in FIG. It is arranged at intervals. Each bearing plate 23 is press-fitted from above into a groove 25 formed in the side surfaces 14b, 14b which are perpendicular to the intake air flow direction (direction of the axis A) and face each other, or are fixed by screws 26. The groove 25 extends in the valve sliding direction indicated by the arrow B, and is formed from the upper end surface 11a of the carburetor body 11 to the sliding cylinder bottom surface 11b (FIG. 1).
[0013]
As shown in FIGS. 2 and 3, a groove 27 that engages with the roller bearing 22 is formed on both sides 13 a of the sliding valve 13 along the arrow B direction (FIG. 3). In the sliding state of the sliding valve 13, the roller bearing 22 is in contact with one of the groove side surfaces that define the groove 27, thereby ensuring the smooth vertical movement of the sliding valve 13.
[0014]
Of the pair of side surfaces 14b, 14b, on the side surface 14b farther from the air funnel 21 (FIG. 1), an annular groove 28 is formed in a sliding surface portion around the intake passage 12, and the groove 28 has a ring shape. The leaf spring 29 and the seal ring 30 are fitted. The seal ring 30 is for preventing the intake air from leaking from the periphery of the slide valve 13 to the downstream side of the intake passage 12 when the slide valve 13 is fully closed or the like. The sliding spring 13 is pressed against the sliding valve 13 by the elastic force of the leaf spring 29 to ensure airtightness between the sliding valve 13 and the sliding cylinder 14.
[0015]
A method for manufacturing a vaporizer having the above-described configuration will be described below with reference to FIG.
[0016]
The carburetor body 11 has an approximate outer shape formed by casting, and portions 12 ′ and 14 ′ corresponding to the intake passage 12 and the sliding cylinder 14 are also formed by casting. FIG. 4A shows, as an example, a die-cut state in which the carburetor body 11 is manufactured using a mold 31 such as a sand mold or a shell mold, and the intake passage portion 12 ′ and the sliding cylinder portion 14 ′. Is molded into a shape close to its completed shape by the cores 32 and 33 arranged in the mold 31.
[0017]
After the general shape of the carburetor body 11 is obtained in this way, as shown in FIGS. 4B and 4C, the inner wall surface 14b 'of the sliding cylinder portion 14' is oriented in the direction of the intake passage axis A. And an end milling process is performed along a direction C perpendicular to the sliding direction B. This processing is performed by moving a cylindrical cutting tool 34 from one side 14a 'of the sliding cylinder portion 14' to the other side 14a 'while rotating, so that a constant width dimension and roughness are obtained in this grinding direction. To form a sliding surface having Therefore, unlike the broaching method in which the tool is moved up and down in the direction of arrow B in the sliding cylinder, the processing lower end surface (sliding bottom surface 11b) can be easily flattened, and the lower end is opened by the tool. Not even.
[0018]
In performing this end milling, both corners of the sliding cylinder side portion 14a 'are portions that the cutting edge of the cutting tool 34 does not reach (a cutting tool escape portion). Since the bearing plate 23 having the structure shown in FIG. 3) is installed and does not become a substantial sliding portion, there is no need for grinding.
[0019]
As described above, after the sliding cylinder 14 having dimensions and surface roughness suitable for the sliding valve 13 is formed, as shown in FIG. The bearing plate 23 is press-fitted or tightened with screws 26. A ring-shaped leaf spring 29 and a seal ring 30 are sequentially fitted in an annular groove 28 formed around the intake passage 12 before and after this, and thereafter the sliding valve 13 is moved from above the sliding cylinder 14. Will be inserted.
[0020]
As described above, according to the present manufacturing method, the sliding cylinder 14 of the vaporizer main body 11 is formed by a combination of the casting die cutting and the end mill processing using the cylindrical cutting tool 34. Is not opened, so that it is not necessary to close the open end with a separate member, so that the manufacturing cost can be reduced and the structure of the vaporizer can be simplified. Furthermore, the number of parts of the vaporizer according to the present production method is smaller than that of the method of assembling the vaporizer body with two separate parts.
[0021]
FIGS. 5 and 6 show the configuration of the main part of a sliding valve carburetor manufactured by the manufacturing method of the second embodiment. In these figures, the same reference numerals as in the first embodiment denote parts having the same configuration as in the first embodiment.
[0022]
The side surface 42 of the vaporizer main body 41 in the second embodiment is constituted by a cylindrical concave surface. The bearing plate 43 has a cylindrical convex surface 43a in close contact with the side surface 42 and a flat surface 43b located on the sliding valve 13 side, and the roller bearing 22 is provided on the flat surface 43b. The bearing plate 43 is fixed to the carburetor main body 41 by screwing the screws 26 from outside the carburetor main body 41.
[0023]
Also in this embodiment, similarly to the first embodiment, end milling is performed along a direction C perpendicular to the axial direction of the intake passage and perpendicular to the displacement direction of the sliding valve. That is, the cutting tool 34 rotates and moves from one side of the carburetor body 41 to the other side (along the direction of arrow C in FIG. 6), whereby the inner surface of the carburetor body 41 is ground. Then, the side surface 42 is formed as a cylindrical concave surface. The side surface 42 formed in this manner may be processed to a smoother surface as needed.
[0024]
In addition, besides the roller bearing 22 described above, a ball bearing or the like may be used as the sliding reduction member.
[0025]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the number of parts of the sliding valve carburetor, easily manufacture the sliding valve carburetor, and reduce the manufacturing cost. Can be
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a vaporizer manufactured by a manufacturing method according to a first embodiment of the present invention.
FIG. 2 is a view showing a state in which the vaporizer main body of FIG. 1 is viewed from above.
FIGS. 3A and 3B show a sliding cylinder portion of the carburetor of FIG. 1, wherein FIG. 3A shows an exploded state of the portion and FIG. FIGS. 4A and 4B show a method for manufacturing a vaporizer according to an example, in which FIG. 5A shows a casting state of a vaporizer main body, and FIGS.
FIG. 5 is a perspective view showing a main part of a vaporizer manufactured by a manufacturing method according to a second embodiment of the present invention.
FIG. 6 is an exploded perspective view showing a main part of a vaporizer according to a second embodiment.
[Explanation of symbols]
Reference Signs List 11 carburetor body 12 intake passage 13 sliding valve 14 sliding cylinder 22 roller bearing 23, 43 bearing plate A intake passage axis B sliding direction of sliding valve

Claims (3)

A sliding body including a carburetor body having a sliding cylinder communicating with the intake passage, and a sliding valve slidably supported in the sliding cylinder and projecting into the intake passage to change a flow area of the intake passage. A valve-operated carburetor,
On both sides of the sliding valve, while being opened in a direction orthogonal to the axis of the intake passage and the sliding direction, grooves are formed along the sliding direction, and on both sides of the sliding cylinder, Bearing plates each having a plurality of bearings fitted into each of the grooves to reduce sliding resistance between the sliding valve and the sliding cylinder are mounted, and in a sliding state of the sliding valve, The sliding valve type carburetor, wherein the bearing is in contact with one of the groove side surfaces defining the groove in each of the grooves . 2. The sliding valve carburetor according to claim 1, wherein both sides of the sliding cylinder are formed into a cylindrical concave surface, and the bearing plate has a cylindrical convex surface which is tightly fixed to the cylindrical concave surface. . An annular groove surrounding the intake passage is formed on the sliding surface of the sliding cylinder, and a seal ring pressed into contact with an end surface of the sliding valve is fitted into the groove. The sliding valve type vaporizer according to claim 1.

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