JPS6314053Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a carburetor coupling device that is connected via an insulator.

When a carburetor is placed close to a cylinder due to space constraints, such as in a general-purpose engine, an insulator is installed at the connection part of the carburetor to prevent conduction heat from the cylinder. Generally, insulators, carburetors, etc. are equipped with stud bolts.
Attach by tightening the air cleaner together. As shown in FIG. 2, the conventional insulator has the same shape as the connecting seat surface of the cylinder block, and is connected by inserting a stud bolt. As a result, the stud bolt and insulator come into contact, and heat is conducted to the insulator located close to the carburetor.
This resulted in the carburetor being heated. Despite installing an insulator, the temperature of the carburetor rose and the fuel boiled, making it impossible to warm up and restart the engine.

The purpose of this invention is to improve the above points and provide a carburetor coupling device that changes the shape of the insulator to reduce the chance of contact with the stud bolt, thereby preventing heat from being transferred to the carburetor. It is something to do.

The figure will be explained in detail below.

Fig. 1 is a cross-sectional view of the intake passage of a general-purpose engine showing an embodiment of this invention, and Fig. 3 is a cross-sectional view taken from Fig. 1 A-A.
FIG. 4 is a front view of the insulator as seen from the arrow, and FIG. 4 is a plan view as seen from the arrow B in FIG.

The engine is of the side valve type, and the cylinder 2, piston 3, combustion chamber 4, intake passage 5, intake valve 6, etc. provided in the cylinder block 1 are arranged in a very conventional manner. The end of the intake passage 5 opens into a boss 7, and two stud bolts 8 for attaching a carburetor 9 are installed on the end face of the boss, sandwiching this opening. The carburetor 9 is provided with locking grooves 10 having a U-shaped cross section on both sides, and the stud bolts 8 are held in the locking grooves 10.
Stack the air cleaner cases 11 and tighten with nuts 12.

An insulator 15 is held between the end face of the boss 7 and the carburetor 9 via gaskets 13 and 14. The insulator 15 has a cylindrical shape with an outer diameter sufficiently smaller than the distance between the two stud bolts 8, and the width in the axial direction is appropriately set. An ear piece 16 having a U-shaped recess 17 at its tip extends from the outer surface of the central portion of the width. Recessed portion 17 of this ear piece 16
The insulator 15 is attached to the end face of the boss 7 by fitting the inside of the stud bolt 8 into the inner side of the stud bolt 8. During assembly, this concave portion 17 engages with the stud bolt 8 and has the function of preventing rotation and falling off, making assembly easy. However, when the carburetor 9 is stacked and tightened with the nut 12, the concave portion 17 The posture is controlled and fixed so that the stud bolt 8 does not come into contact with the stud bolt 8.

Due to the above configuration, compared to the conventional insulator shown in FIG. 2, the insulator 15 of this invention does not contact the stud bolt 8, so there is no direct heat conduction, and even if there is contact, the area is extremely small. , and the amount of heat conducted is small. The area of contact with the end face of the boss 7 is also reduced, reducing the amount of heat conducted there.Furthermore, since the stud bolt 8 is exposed to the outside at the recess 17, heat is radiated and the heat carried by the stud bolt 8 to the carburetor 9 is reduced. Make less. In this way, the heat transferred to the carburetor 9 is suppressed as a whole.

As mentioned above, the carburetor coupling device according to this invention prevents the intervening insulator from rotating or falling off by means of protruding ears, and prevents it from coming into contact with the stud bolt under normal conditions. Reduces heat transferred from the cylinder block to the carburetor, suppresses fuel boiling, and improves warm-up restart performance. In addition, the ear pieces are only provided at the center of the axial width of the insulator;
Since the stud bolt is placed with a gap in the recessed part of the ear of the opening at the tip of the insulator,
There is no direct contact between the stud bolt and insulator when assembled, allowing outside air to easily circulate through the gap.
Since a large amount of air is exposed to the outside air, thermal insulation is provided by air, and the stud bolt is actively cooled. In this case, by forming the ears, the outer diameter of the insulator can be made small, and therefore the contact area with the cylinder boss surface is small, and the amount of heat conduction is small, so that the insulation effect of the carburetor can be further improved. In addition, the insulator can now have a sufficient heat insulating function even if the width in the axial direction is reduced, which helps in cost reduction and effective use of space, making it effective for use in general-purpose engines.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional side view of the intake passage of a general-purpose engine showing an embodiment of this invention, Fig. 2 is a front view illustrating a conventional insulator, and Fig. 3 is a front view of the insulator as viewed from the arrow A-A in Fig. 1. FIG. 4 is a plan view taken in the direction of arrow B in FIG. 3. 1...Cylinder block, 5...Intake passage, 7
... Boss, 8 ... Stud bolt, 9 ... Carburetor, 11 ... Air cleaner case, 12 ... Nut, 15 ... Insulator, 16 ... Ear piece,
17...Concave part.

Claims (1)

[Scope of utility model registration request] A stud bolt is installed on the end face of the intake passage boss protruding from the cylinder block across the intake passage.
By tightening the nut to this stud bolt,
In a carburetor connection device in which an insulator, a carburetor, and an air cleaner case are fastened together, the outer diameter of the insulator interposed between the boss end face and the carburetor is sufficiently smaller than the spacing between stud bolts, and the axial width center of the outer circumference is A carburetor connection characterized in that a lug having a recess with an opening at the tip protrudes from both sides of the lug, and the inner half of the stud bolt is held in the recess of the lug with a gap therebetween. Device.