JPH05187324A - Rotating shaft in carburetor - Google Patents

Abstract

PURPOSE:To reduce manufacturing cost of a rotating shaft by employing a new plating method, in place of hard chromium plating, for plating the surface of the rotating shaft which is low in cost and provides high abrasion resistance. CONSTITUTION:A butterfly valve 5, supported rotatably in bearing holes 4 bored across an air intake channel 2 which pierces through a carburetor body 1, controls opening/closing of the air intake channel 2. The rotating shaft 3 is formed of a free cutting metal such as brass, and is coated with a superfine diamond particle film in such a manner that superfine particle diamond is added to nickel and phosphor bath which is suitable for electroless plating, and the superfine particle diamond is eutectically formed in phosphor and nickel which are deposited by electroless plating.

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, of which a butterfly valve which is rotatably supported by a carburetor body and which opens and closes an intake passage is attached. The present invention relates to a rotary shaft of a vaporizer.

[0002]

2. Description of the Related Art A choke valve shaft as a rotating shaft is rotatably supported in a bearing hole formed in the carburetor main body on the upstream side of the intake passage of the carburetor main body, and is attached to the choke valve shaft. A choke valve as a butterfly valve that opens and closes the intake passage is attached. On the other hand, on the downstream side of the intake passage of the carburetor body,
A throttle valve shaft serving as a rotary shaft is rotatably supported in a bearing hole formed in the carburetor body, and a throttle valve serving as a butterfly valve for opening and closing an intake passage is attached to the throttle valve. The rotary shafts rotate in the forward and reverse directions, and the butterfly valve controls the intake passage to a desired opening degree by this rotation. Such a rotating shaft repeatedly rotates in the bearing hole during the operation of the engine, and it is common to form a hard chrome coating on the surface of the rotating shaft in order to improve the wear resistance of the rotating shaft. It was

[0003]

The hard chrome coating (hard chrome plating) formed on the rotary shaft in this manner has the following problems. Hard chrome plating is done by electroplating. This electroplating uses a DC rectifier to deposit the metal ions of the plating solution in the plating bath on the product on the anode, that is, on the rotating shaft. According to such electroplating, the current density around the protrusion of the product tends to be higher than the current density of the recess, so that a thick coating is formed on the protrusion and a thin coating is formed on the recess. Looking at the conventional rotary shaft, the rotary shaft is provided with a notch step portion for attaching the butterfly valve, a notch groove, and a screw hole for screwing the butterfly valve onto the rotary shaft. If the above-mentioned hard chrome coating is formed on the rotating shaft by electroplating, an abnormally thick coating will be formed on the edge part formed by the notch step, the notch groove, and the screw hole of the rotating shaft. It interferes with the operation of the valve. That is, the rotating shaft, a relatively small gap in the bearing hole,
For example, the bearing is supported with a minute gap of about 0.05 mm. (The bearing of the rotating shaft in the minute gap prevents the air from entering into the intake passage from this surrounding gap and causes a small amount of air. If a part of the rotating shaft becomes thick, it will hinder the operation of the rotating shaft.

Further, according to electroplating, the thickness of the coating film formed on each rotating shaft varies due to the difference in the location of the rotating shaft in the plating tank. That is, the plating film varies among products of the rotating shaft.
Based on the above, after forming a hard chrome coating on the rotating shaft, it is necessary to round the thick parts of the edges and edges, or to remove the plating of the thick parts, and finally to make all the rotating shafts I had to go through the inspections and make a pass / fail decision. In this way, modifying the thick-walled part and performing 100% inspection after the plating process increase the manufacturing cost of the rotary shaft, and in addition, defects in this inspection increase the damage cost. Not preferable. Also, the surface of the hard chrome plated film has a pointed shape, and it is necessary to buff the surface of the rotating shaft to improve the operability, which also causes a high manufacturing cost of the rotating shaft. Become.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the manufacturing cost of a rotary shaft is improved by providing a novel plating process which replaces the hard chrome plating on the surface of the rotary shaft and has a high wear resistance. Is to reduce.

[0006]

In order to achieve the above object, the rotary shaft in the vaporizer according to the present invention is formed of a free-cutting metal such as brass and the like, and nickel or phosphorus plating solution capable of electroless plating. Is added with ultrafine diamond, and the ultrafine diamond is co-deposited in Rickel or phosphorus deposited by electroless plating to form an ultrafine diamond coating on the surface of the rotating shaft.

[0007]

[Function] By electroless plating, the end of the rotating shaft,
It is possible to form a uniform plating thickness between the edge portion and the rotating shaft. Since the ultrafine-flow diamond coating can be formed on the surface of the rotating shaft, the wear resistance of the rotating shaft can be favorably maintained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotary shaft in a vaporizer according to the present invention will be described below with reference to FIG. Reference numeral 1 denotes a carburetor main body having an intake passage 2 penetrating laterally through the inside thereof, and a downstream intake passage 2A downstream of the venturi portion V (right side in the figure)
Is formed, and the upstream intake passage 2B is formed on the upstream side of the Venturi portion V. A throttle valve shaft 3 as a rotating shaft traverses in the downstream side intake passage 2A, and both ends of the throttle valve shaft 3 are rotatably supported by bearing holes 4 formed in the carburetor body 1. A throttle valve 5 serving as a butterfly valve that opens and closes the downstream intake passage 2A is attached to the throttle valve shaft 3 with a screw B or the like. The throttle valve shaft 3 is provided with a notch groove 3A for holding the throttle valve 5, and a screw hole 3B is formed orthogonal to the notch groove 3A. The throttle valve shaft 3 is shown in FIG.

A choke valve shaft 6 as a rotating shaft traverses in the upstream intake passage 2B, and both ends of the choke valve shaft 6 are rotatably supported in bearing holes formed in the carburetor body 1. To be done. A choke valve 7 as a butterfly valve that opens and closes the upstream intake passage 2B is attached to the choke valve shaft 6 with a screw B or the like. The choke valve shaft 6 is formed with a notch step portion 6A on which the choke valve 7 is mounted and a screw hole 6B which is orthogonal to the notch step portion 6A. The choke valve shaft 6 is shown in FIG.

After the throttle valve 5 is placed in the notch groove 3A of the throttle valve shaft 3 which crosses the downstream side intake passage 2A, the screw B is placed.
The throttle valve 5 is attached to the throttle valve shaft 3. On the other hand, the choke valve 7 is arranged on the notched step portion 6A of the choke valve shaft 6 which traverses the upstream intake passage 2B, and is attached to the choke valve 7 and the choke valve shaft 6 with a screw B. The above is a conventionally known vaporizer.

The throttle valve shaft 3 and the choke valve shaft 6 as rotating shafts are formed as follows. The throttle valve shaft 3 and the choke valve shaft 6 are made of electroless nickel or a metal material that can be plated with phosphorus. Tin, lead, zinc, cadmium, antimony,
Are those that cannot be electroless nickel and phosphorous plated and are excluded. Further, stainless steel is excluded because it can be electrolessly plated with nickel and phosphorus, but is not suitable for processing complicated shapes with poor workability and high material cost. That is, the material of the rotating shaft is preferably electroless nickel, phosphorus-platable, and free-cutting metal such as brass, aluminum, phosphor bronze, and free-cutting steel.

The ultrafine-grained diamond (cluster diamond ... A cluster is a group of several tens to several hundreds of atoms or molecules) coated on the rotating shaft will be described. Ultrafine diamond particles are cubic particles and have rounded particles with an average particle size of 50 angstroms. Therefore, ultrafine diamond is synthesized. (Dynamic high temperature high pressure method)

Then, a method for coating the surface of the rotating shaft with this ultrafine diamond will be described. Ultrafine diamond particles are added to an electroless plating solution, for example, an acidic plating solution, and the rotary shaft is immersed in the plating solution. According to this, the metal ions in the plating solution are deposited as nickel and phosphorus metals by the chemical reaction of the reducing agent, and ultrafine diamond is co-deposited in the deposited metal, and ultrafine diamond is deposited on the surface of the rotating shaft. A film is formed.

Since the ultrafine diamond coating is formed on the surface of the rotary shaft in this manner, the surface hardness of the rotary shaft can be made at least equal to or higher than that of the hard chrome plating, and at the same time, the hardness can be made extremely high. Since the fine-grained diamond forms a round sphere with an extremely small diameter, generation of scratches is suppressed, and a rotary shaft with excellent wear resistance can be provided. Further, the fact that the ultra-fine-grained diamond forms a rounded sphere greatly reduces the friction coefficient and greatly improves the operability of the rotating shaft.

According to the use of electroless plating,
Accurate dimensional accuracy can be obtained because variation in the film thickness between the rotating shafts due to the difference in the arrangement of the rotating shaft 4 in the plating solution can be suppressed.

Furthermore, according to the use of electroless plating,
Notch groove 3A, notch step 6A and screw hole 3 on the rotating shaft
Even if B and 6B are formed and end portions or edge portions are formed by them, by immersing the rotary shaft in the plating liquid, all the portions including the end portion and the edge portion of the rotary shaft are made uniform with the plating liquid. Since it can be brought into contact with, the ultrafine diamond particles can be uniformly coated to the same thickness on all portions of the rotating shaft. This can eliminate the need for secondary processing of the rotary shaft after coating.

Further, since the surface of the rotating shaft coated with the ultrafine diamond is a spherical sphere of the ultrafine diamond, there is no pointed shape on the surface of the rotating shaft, so that the surface of the rotating shaft is smoothed after coating. There is no need to carry out secondary processing such as buffing to do so.

[0018]

As described above, according to the rotary shaft of the vaporizer of the present invention, the rotary shaft is made of a free-cutting metal such as brass and the electroless plating is possible with nickel or phosphorous plating liquid. Rickel, which is added by diamond and deposited by electroless plating, co-deposits ultra-fine diamond in phosphorus and forms a ultra-fine diamond film on the surface of the rotating shaft, resulting in excellent wear resistance, rotation and operability. A good rotation axis can be provided. Further, since the ultrafine diamond film treatment on the rotating shaft is performed by electroless plating, the mutual coating of the rotating shafts can be performed accurately and uniformly, and further, the end portions of the rotating shafts, the complicated shape portions such as the edge portions, etc. In addition, since it is possible to form a uniform coating, the secondary processing after the coating treatment is not necessary at all, and the inspection related to the coating is unnecessary, so that the manufacturing cost of the rotating shaft can be significantly reduced. Further, the fact that the material of the rotary shaft is made of free-cutting metal also contributes to the reduction of manufacturing cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a rotary shaft in a vaporizer of the present invention.

FIG. 2 is an inclined view showing a throttle valve shaft as a rotation shaft.

FIG. 3 is a perspective view showing a choke valve shaft as a rotating shaft.

[Explanation of symbols]

 1 carburetor main body 2 intake passage 3 throttle valve shaft as rotating shaft 3A notch groove 4 bearing hole 5 throttle valve as butterfly valve 6 choke valve as rotating shaft 6A notch step 7 choke valve as butterfly valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F16K 1/22 D 9064-3H

Claims (1)

[Claims] 1. A rotary shaft of a carburetor, which is rotatably supported in a bearing hole formed across an intake passage penetrating the carburetor main body and to which a butterfly valve for controlling opening / closing of the intake passage is attached. In addition, the rotating shaft is made of brass or other free-cutting metal and nickel that can be electroless plated, and ultra-fine diamond is added to the phosphorus plating solution. Rickel is deposited by electroless plating. A rotary shaft in a vaporizer that is formed by depositing an ultrafine diamond film on the surface of the rotary shaft.