JPH04122810U - Crankshaft connection structure of 2-stroke multi-cylinder engine - Google Patents

Abstract

(57) [Summary] [Purpose] To connect both crankshafts between both cranks located below both cylinders and to seal between both crank chambers in a 2-stroke, 2-cylinder engine. [Structure] In a two-stroke multi-cylinder engine configured by mounting crankshafts 3 and 4 on both crank chambers 1a and 2a below both cylinders 1 and 2 arranged in parallel, At least one of the shaft portions 3a, 4a of both crankshafts 3, 4 extending into both crank chambers 1a,
The shaft portion 3 is mounted on the circumferential support surface 5 between the shafts 2a through a bearing 6, and the guide pipe 7 has approximately the same thickness as the bearing 6 and is arranged in parallel to the bearing 6.
a, 4a are press-fitted and connected integrally, and the circumferential support surface 5
A large number of circumferential grooves 8 are formed on the outer peripheral surface of the guide pipe 7 adjacent to the guide pipe 7.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention allows the shaft parts of both crankshafts below both cylinders to be connected and assembled. The present invention relates to a crankshaft connection structure for a two-stroke multi-cylinder engine.

0002

[Conventional technology]

Conventionally, the crankshafts were placed in both crank chambers below both cylinders installed side by side. In a two-stroke multi-cylinder engine configured by As seen in the publication, the crankshaft between both crank chambers is mounted on both bearings. At the same time, there is a thin film between both bearings that can form an annular groove on the outer circumferential surface. A method such as fitting a meat collar and fitting a labyrinth packing around the outer circumference of the collar. The structure is known.

0003

[Problem that the idea aims to solve]

However, as in the conventional example, there is only one crankshaft between both crank chambers. In this structure, bearings, collars, labyrinth packing, etc. are assembled between both crank chambers. It is difficult to attach, and it is also difficult to divide the crankshaft in that area into two and press it against the collar. Even if the collars are inserted and connected, it is difficult to connect them because the collars are thin. Even if the wall is made thicker, a labyrinth packing must be inserted around its outer periphery. Because of this, there is a problem that it is not possible to make the wall thick enough to have sufficient strength. Ru.

0004

[Means to solve the problem]

The present invention solves such problems and effectively creates a labyrinth effect. It has been devised to have a simple structure and be suitable for implementation. At least one of the shaft parts of both crankshafts extending between the two crank chambers is connected between the two crank chambers. The shaft is mounted on the circumferential support surface of the bearing via a bearing, and the thickness is approximately the same as the bearing. Both shaft parts are press-fitted into the guide pipe, which is arranged in parallel with the bearing, and integrated into the guide pipe. The guide pipe has a large number of circles on its outer circumferential surface adjacent to the circumferential support surface. It is constructed by forming a circumferential groove.

[0005]

[Effect]

Therefore, by fitting a bearing to at least one shaft, both crankshafts Press-fitting the shaft into the guide pipe allows for easy assembly and The circumferential groove on the outer circumferential surface of the guide pipe that rotates with the rank shaft is close to the circumferential support surface. However, the labyrinth effect of sealing between both crank chambers can be achieved.

[0006]

【Example】

FIG. 1 shows a side sectional view of the engine section of a brush cutter, which has fins 9 on the outer peripheral surface. Two-stroke cylinder with a small displacement and internal pistons 10a and 10b. 1 and 2 are arranged in parallel and in series, and the crank chambers 1a and 2a are located below both cylinders 1 and 2. mounts the crankshafts 3 and 4 connected to the pistons 10a and 10b, respectively. However, the shaft part between both crankshafts 3 and 4 is divided into shaft parts 3a and 4a, and one shaft The part 3a is mounted on the circumferential support surface 5 between the two crank chambers 1a and 2a via a bearing 6. and a guide pipe having approximately the same thickness as the bearing 6 and installed in parallel with the bearing 6. Both shaft portions 3a and 4a are press-fitted into the pipe 7 and connected integrally to the circumferential support surface 5. A large number of circumferential grooves 8 are formed on the outer peripheral surface of the adjacent guide pipes 7.

[0007] Further, a recoil starter section 11 is connected to the rear shaft section 4b side of the crankshaft 4. A fan 12 and a clutch shoe are connected to the front shaft portion 3b of the crankshaft 3. A flywheel 14 with 13 is mounted on the shaft, and inside the front clutch case 15 there is a , a clutch which is inscribed in the clutch shoe 13 and which drives the cutting blade drive shaft 16. The head drum 17 is mounted on a shaft, and both cylinders 1, An engine cover 18 is placed over the cylinders 1 and 2. In addition to being equipped with a fuel tank 19, carburetor parts 20 are installed on both sides of both cylinders 1 and 2. and a muffler part 21, extending forward from the clutch case 15. On the front end side of the operating rod (not shown), the cutting blade drive shaft 16 has a cutting blade to be driven. When equipped, a brush cutter similar to the conventional type is constructed.

[0008] Therefore, by fitting the bearing 6 to one shaft portion 3a, both crankshafts 3, 4 By press-fitting the shaft parts 3a and 4a into the guide pipe 7, both crankshafts 3 and 4 can be easily connected. This means that it can be assembled and mounted on a shaft, and rotates together with the shaft parts 3a and 4a. While the circumferential groove 8 on the outer peripheral surface of the guide pipe 7 approaches the circumferential support surface 5, A labyrinth effect can be achieved that seals between the two crank chambers 1a and 2a. .

[0009]

[Effect of the idea]

In this way, the present invention provides at least one of the shaft portions 3a, 4a of both crankshafts 3, 4. At the same time, fit the bearing 6 into the guide pipe 7 and press-fit both shaft parts 3a and 4a into the guide pipe 7. By doing so, it can be easily assembled, and the shaft parts 3a, 4a and While the circumferential groove 8 on the outer circumferential surface of the guide pipe 7 that rotates is close to the circumferential support surface 5, Demonstrates a labyrinth effect and can reliably seal between both crank chambers 1a and 2a. Therefore, the shaft connection and labyrinth effect can be effectively created between the two crank chambers 1a and 2a. It has a simple structure that is easy to operate and manufacture, and is suitable for 2-stroke multi-cylinder engines. It has the advantage of being able to be implemented in many ways.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an engine section according to an embodiment of the present invention.

FIG. 2 is a plan view showing a part of FIG. 1;

FIG. 3 is a side view showing the entire engine section.

FIG. 4 is a front view showing the entire engine section.

[Explanation of symbols]

1 cylinder 2 cylinders 3 Crankshaft 4 Crankshaft 1a Crank chamber 2a Crank chamber 3a Shaft part 4a Shaft part 5 Circumferential support surface 6 Bearing 7 Guide pipe 8 Circumferential groove

Claims (1)

[Scope of utility model registration request] Claim 1: In a two-stroke multi-cylinder engine configured by mounting crankshafts 3 and 4 in both crank chambers 1a and 2a below both cylinders 1 and 2 arranged in parallel, Both crankshafts 3, 4 extending between
At least one of the shaft portions 3a, 4a of the crank chamber 1
The guide pipe 7 is mounted on the circumferential support surface 5 between a and 2a via a bearing 6, and has approximately the same thickness as the bearing 6, and is provided in parallel with the bearing 6. , 4a are press-fitted and integrally connected, and a number of circumferential grooves 8 are formed on the outer circumferential surface of the guide pipe 7 adjacent to the circumferential support surface 5. structure.