JPH0618622U - Engine cover structure for small engines - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an engine cover structure that restricts the escape of cooling air to the plug cover portion to improve the cooling effect and also has excellent strength. [Configuration] Cover body 2 that guides cooling air to the outer circumference of the cylinder
Further, an air guide rib 27 is vertically provided on the inner surface of the plug cover portion 25 of the cover body 2 in a direction of blocking the flow of the cooling air from the cooling air passage 17 to the plug cover portion 25. The engine cover structure has a small gap 28 formed between the upper end surface of the cylinder 3 and the cylinder 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an engine cover structure applied to a small general-purpose engine for portable working machines such as a chain saw, a head trimmer, and a brush cutter.

[0002]

[Prior art]

 In a small general-purpose engine for a portable work machine, the cylinder is usually covered with a cover from the upper part to the outer peripheral part.

This type of cover body is generally made of synthetic resin and has a hat shape, and is attached to the engine body with an appropriate gap formed with the cylinder. When the cover body is attached only at the lower part of the peripheral wall of the cover body, when the cover body is subjected to a larger external force than the upper side, the cover body is greatly deformed and may be cracked in some cases.

In order to prevent such a large deformation of the cover body, there has been proposed a structure in which the upper wall portion of the cover body is attached to the upper surface of the cylinder in addition to the attachment of the lower portion of the cover body peripheral wall. (See, for example, Japanese Utility Model Laid-Open No. 62-165439).

[0005]

[Problems to be solved by the device]

 However, the above-mentioned configuration in which the upper wall portion of the synthetic resin cover body is fixed to the upper surface of the cylinder has the following problems.

(A) A screw is used to attach the cover body to the upper surface of the cylinder. However, in addition to forming a gap between the cover body and the cylinder, the cover body is directly attached to a cylinder or a cylinder at a high temperature portion. Insulation is required to prevent access to the mounting screws screwed onto the top surface. Assembling this heat insulating material and machining screw holes on the top of the cylinder will increase the production cost.

(B) Since the temperature of the mounting screw head exposed to the outside becomes high, it is necessary to take measures against the heat. Further, the form in which the mounting screw head is exposed on the central surface of the upper wall of the cover body is not preferable from the design surface.

(C) Since the plug cover is provided separately from the engine cover, the number of parts increases and the production cost increases.

The present invention has been made in view of the above points, and in a cover body integrally provided with a plug cover portion, it is possible to limit the escape of the cooling air to the plug cover portion and to improve the strength. Also aims to provide an excellent engine cover structure.

[0010]

[Means for Solving the Problems]

 The gist of the present invention for achieving the above-mentioned object is a cover body that covers a cylinder and forms a cooling air passage that guides cooling air generated in a fan housing to an outer peripheral portion of the cylinder. On the inner surface of the plug cover formed by opening the body upper wall diagonally upward, a wind guide rib is hung vertically in a direction that blocks the flow of cooling air from the cooling air passage to the plug cover. The engine cover structure for a small engine is characterized by forming a small gap between the rib and the upper surface of the cylinder.

[0011]

[Action]

 Attach a cover to the engine body to form a cooling air passage around the cylinder. A part of the cooling air that escapes from the cooling air passage to the plug cover part is limited by the air guide ribs that hang vertically on the inner surface of the plug cover part, and is turned to the cylinder side to increase the amount of air that is effectively used to cool the cylinder. To do.

[0012] The air guide ribs provided vertically on the inner surface of the plug cover portion reinforce the plug cover portion, and when a force for pressing the plug cover portion against the engine is applied to the plug cover portion, the plug cover portion is pressed. When the part is slightly deformed, the lower end of the air guide rib comes into contact with the upper surface of the cylinder, and the plug cover part is directly held by the cylinder cover abutting part, preventing large deformation of the plug cover part and leading to cover cracking. There is no stopping.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an engine to which the present invention is applied, FIG. 2 is a cover body sectional view taken along line aa of FIG. 1, and FIG. 3 is a cover body sectional view taken along line bb of FIG.

In the figure, 1 is an engine body and 2 is a cover body.

The engine body 1 constitutes an air-cooled engine by providing fins 4 in multiple stages on the outer peripheral portion of the cylinder 3, and an air cleaner 5 is provided on one side of the cylinder 3 at a predetermined distance from the cylinder 3 and another on the other side. A muffler 6 is installed, a recoil starter 8 (a handle is shown in Fig. 1) is installed in the crankcase 7 at the front of the engine, and dynamic power is applied to the fan housing 9 attached to the crankcase 7 at the rear of the engine. The outlet 10 is open.

The cover body 2 is made of a synthetic resin (molded product), and has a peripheral wall 12 extending downward from the upper wall 11 to form a hat shape, and is covered with the engine body 1 to be hung from the cylinder 3 to the muffler 6. Cover. A large number of ventilation holes 14 are formed in the muffler side peripheral wall portion 13 of the cover body 2, and the air cleaner side peripheral wall portion 15 is inserted in the gap between the cylinder 3 and the air cleaner 5.

In FIG. 3, reference numeral 16 is a baffle plate which is erected in parallel on both sides of the cylinder 3, and the baffle plate 16 and the cover body 2 form a cooling air passage 17 around the cylinder 3. The cooling air passage 17 communicates with the inside of the fan housing 9 at the rear of the engine, and communicates with the cooling air exhaust hole 18 provided at the front peripheral wall portion 19 of the cover body 2 at the front of the engine to generate the cooling air generated within the fan housing 9. To the outer circumference of cylinder 3.

In FIG. 2, reference numerals 21 and 22 denote attachment portions provided on the lower portion of the front peripheral wall portion 19 and the lower portion of the rear peripheral wall portion 20 of the cover body 2 for attaching the cover body 2 to the engine body 1. The part 21 has a configuration in which the lower edge of the front side peripheral wall part 19 is sandwiched between the crankcase 7 and the recoil starter 8.When mounting the recoil starter 8 on the crankcase 7, the mounting screw 23 common to the recoil starter 8 is used. The mounting portion 22 is provided with a screw insertion hole in the lower portion of the rear side peripheral wall portion 20 and is attached to the fan housing 9 by using a dedicated mounting screw 24. There is.

Reference numeral 25 denotes a plug cover portion formed on the upper wall 11 of the cover body 2, which opens obliquely upward in accordance with the inclination of the plug 26 attached to the upper surface of the cylinder 3 so that the plug cap 26 ′ from the outside can be prevented. It is designed to be removable.

Reference numeral 27 denotes an air guide rib vertically provided on the inner surface of the plug cover portion 25 in a direction of blocking the flow of the cooling air from the cooling air passage 17 to the plug cover portion 25. The air guide rib 27 and the cylinder are provided. A small gap 28 is formed between the upper surfaces. The small gap 28 is generally about 0.5 to 4 mm, although it depends on the material and shape of the cover body 2.

In FIG. 3, reference numeral 29 is a wind guide rib vertically provided on the lower surface of the upper wall 11 of the cover body 2 corresponding to the upper end of the wind guide plate 16. The wind guide rib 29 is a cooling air discharge hole. The cooling air is provided in the direction in which the cooling air is guided in 18 to prevent the cooling air from leaking between the upper end of the baffle plate 16 and the cover body 2 by making surface contact with the upper end of the baffle plate 16. .

In the above structure, the engine body 1 is covered with the cover body 2, and the air guide plate 16 and the air guide rib 29 form the cooling air passage 17 around the cylinder. Then, a small gap 28 is formed between the air guide rib 27 vertically provided on the inner surface of the plug cover portion 25 and the upper end surface of the cylinder 3 to restrict the cooling air from the cooling air passage from coming out to the plug cover portion 25.

[0024]

EFFECTS OF THE INVENTION According to the present invention having the above configuration, the following effects are achieved.

(1) On the inner surface of the plug cover part, since the air guide ribs are provided vertically in a direction that blocks the flow of the cooling air from the cooling air passage to the plug cover part, the cooling air from the cooling air passage is plugged into the plug cover part. The leakage of the cooling air from the inside of the cooling air passage is reduced and the amount of cooling air that is effectively used for cooling the cylinder is increased to improve the cooling efficiency of the cylinder.

(2) Since a small gap is formed between the air guide ribs and the upper surface of the cylinder, the plug cover is deformed by an external force. By making contact, the plug cover part is directly held by the cover abutting part on the top surface of the cylinder to make it difficult for subsequent deformation. In addition, the air guide ribs hung on the inner surface of the plug cover portion reinforce the plug cover portion to reduce the cracking of the cover due to the deformation of the plug cover portion, resulting in excellent strength.

(3) Since the cover body does not need to be attached to the cylinder, it does not require heat countermeasures, and the number of parts can be reduced, which is advantageous in terms of production cost. It is also excellent in terms of design because there is no mounting screw for mounting the cover body to the cylinder.

[Brief description of drawings]

FIG. 1 is an overall perspective view of an engine to which the present invention is applied.

FIG. 2 is a cross-sectional view of the main part taken along the line aa in FIG.

3 is a cross-sectional view of the main part taken along the line bb of FIG.

[Explanation of symbols]

 1 ... Engine body 2 ... Cover body 3 ... Cylinder 11 ... Cover body upper wall 16 ... Air guide plate 17 ... Cooling air passage 21 ... Mounting portion 22 ... Mounting portion 25 ... Plug cover portion 27 ... Wind guiding rib 28 ... Small gap

Front page continuation (72) Inventor Katsumi Kinoshita 1-1 Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries Ltd. Akashi Plant (72) Inventor Yasuhiko Nozawa 1-1, Kawasaki-cho, Akashi-shi, Hyogo Akashi Kawasaki in the factory

Claims (1)

[Scope of utility model registration request] 1. A cover body for covering a cylinder and forming a cooling air passage for guiding cooling air generated in a fan housing to an outer peripheral portion of the cylinder, the cover body being formed by obliquely opening upward on an upper wall of the cover body. On the inner surface of the plug cover portion, air guide ribs are vertically provided in a direction that blocks the flow of cooling air from the cooling air passage to the plug cover portion, and a small gap is formed between the air guide ribs and the upper surface of the cylinder. Engine cover structure for small engines.