JPS6314026Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a vibration isolating device for portable working machines such as chain saws and brush cutters, and is easy to manufacture.
Moreover, the purpose is to provide a structure that can easily maintain accuracy during mass production. Among portable working machines, for example, a chain saw has a left side view as shown in Figure 1 and a front view as shown in Figure 2, with four vibration isolators 2 installed on the front half of the handle 1 (main handle). A power part 3 with a built-in engine is supported,
A band-shaped guide plate 4 protruding forward from the power section 3
A saw chain 5 is attached to the outer periphery. 6 is an auxiliary handle, 7 is a starter handle, and 8 is a throttle lever. When the engine is started with the starter handle 7, the throttle lever 8 is grasped together with the handle 1 with the right hand, and the auxiliary handle 6 is held with the left hand to perform sawing work, the vibration of the power part 3 is blocked by the vibration isolator 2. It is becoming more and more like this.

In FIG. 3, which is a cross-sectional view taken from FIG. 12 is an engine cover.

Conventionally, the structure of the part corresponding to Fig. 3 is shown in Fig. 7.
The ones shown in Figs. to 9 are known. One end of the anti-vibration rubber 13 shown in FIG. 7 is press-fitted into the anti-vibration rubber mounting hole 14 of the crankcase 11, and a mounting plate 15 baked into the other end is fastened to the handle 1 with bolts 16. That is, since the vibration isolator shown in FIG. 7 does not have an amplitude limiting mechanism, when the crankcase 11 vibrates with respect to the handle 1 in the direction of arrow X ₁ or perpendicular to the plane of the paper,
The amplitude becomes too large. That is, when a constant load is applied, the amount of movement becomes too large, which inevitably causes practical problems such as the position of the saw chain becoming unstable. Since the vibration isolating rubber 17 shown in FIG. 8 is not provided with an amplitude limiting mechanism, it has the same problem as that shown in FIG. 7. The holder 1 is attached to the vibration isolating rubber 18 in Fig. 9.
9 is attached, and the holder 19 is the anti-vibration rubber 1
8, and the inner surface of the cylindrical wall 20 has an asymptotic cross-sectional shape with respect to the outer circumferential surface of the vibration isolating rubber 18 (Japanese Utility Model Publication No. 53-111997). That is, the cylindrical wall 20
plays the role of an amplitude limiting mechanism, and the handle 1
On the other hand, when the crankcase 11 is deflected in the direction of arrow _X1 , the spring constant (load) of the vibration isolating rubber 18 increases in a quadratic curve as the amount of deflection increases, and the cylindrical wall 20 plays the role of a stopper. In this case, the cylindrical wall 2
The curved shape of the inner surface of the cylindrical wall 20 will affect the characteristics, but the cylindrical wall 20 must have sufficient rigidity to serve as a stopper, so it is difficult to create an accurate curved shape. . For example, when press molding is performed from a steel plate, the mold is subject to severe wear, and the inner shape of the cylindrical wall 20 is likely to change during continued mass production. Furthermore, the inner surface shape changes due to variations in the steel plates used. In short, it is difficult to manufacture because it has a structure in which a complicated inner surface shape is formed on the hard metal cylindrical wall 20, and it is difficult to maintain high precision quality during mass production.

The present invention solves the above-mentioned conventional problems by making the shape of the metal part that acts as an amplitude limiting mechanism a simple cylinder, and by forming a cross-sectional shape on the surface of the soft anti-vibration rubber that has a subtle effect on the spring characteristics. FIG. 3 will be explained in detail.

In FIG. 3, the outer peripheral surface of the cylindrical vibration isolating rubber 10 is
Convex tapered outer peripheral surface 2 provided at the middle part in the length direction
A large diameter outer circumferential surface 24 is formed at the large diameter side end of 2 through a stepped portion 23.
The outer circumferential surface 24 is press-fitted into the large diameter part of the hole 25 of the crankcase 11 which serves as a stopper, and holds the vibration isolating rubber against the stopper.
The small diameter cylindrical surface 25a of the hole 25 faces the convex tapered outer circumferential surface 22 of the vibration isolating rubber 10, and a gap 26 is formed between the outer circumferential surface 22 and the cylindrical surface 25a, which increases toward the handle 1 side. Looking at it another way,
Vibration-proof rubber outer circumferential surface 22 and crankcase inner circumferential surface 25
An asymptotic gap 26 that approaches the step part 23 side is provided between a. A mounting plate 15 baked onto the end of the anti-vibration rubber 10 is fastened to the handle 1 with bolts 16. 27 is anti-vibration rubber 10
This is an annular reinforcing plate that is integrally cast inside.

Crankcase 11 against handle 1 while driving
When the vibration isolating rubber 10 vibrates in the direction _of arrow
As the amount of deflection increases, the contact area between the vibration isolating rubber outer circumferential surface 22 and the crankcase cylindrical surface 25a moves toward the handle 1 side, the span of the vibration isolating rubber 10 increases, and the spring constant increases. to perform the stopper action. The increase in load due to the increase in the amount of deflection becomes quadratic.

In the embodiment shown in FIG. 3, the hard crankcase 11 is formed with a cylindrical surface 25a that can be finished with high precision by lathe processing, etc., and the soft anti-vibration rubber 10 is formed with a convex taper to give delicate spring characteristics. Since the shaped outer circumferential surface 22 is formed, there is no fear that the mold will be damaged even when mass producing the vibration isolating rubber 10, and it is possible to easily continue manufacturing highly accurate vibration isolating rubber 10. Therefore, there is an advantage that products with uniform performance of the vibration isolator 2 can be mass-produced. Further, since the vibration-proof rubber is held by the large-diameter outer circumferential surface 24 provided coaxially with the circumferential wall 25a, it is possible to prevent variations in performance due to errors during assembly.

The anti-vibration rubber 28 shown in FIG. cylindrical wall 31
An asymptotic gap 33 is formed between the cylindrical surface 32 and the inner circumferential surface 29 of the anti-vibration rubber. In this case as well, the cylindrical wall 3
The outer periphery of 1 can be formed into a cylindrical surface 32 that is easy to finish with high precision, making it easy to process, and the soft anti-vibration rubber 28 has a circumferential surface 29 with a complicated cross-sectional shape, which makes manufacturing easier. It is easy to mass-produce high-quality vibration isolators. Although manufacturing is easier because there is no need to drill high-precision holes in the crankcase 11, which is a large component, the bolts 30 are integrated into the columnar wall 31, so there is no need to increase the number of parts. , costs can be reduced.

In the embodiment shown in FIG.
A cylindrical surface 34 is formed on the vibration isolating rubber 35, and a convex tapered outer peripheral surface 36 is formed on the vibration isolating rubber 35. In the embodiment shown in FIG. 6, instead of forming a cylindrical surface on the crankcase 11, a cylindrical wall 38 with a simple shape is provided on the holder 37, and this cylindrical wall 38 is connected to the convex tapered outer peripheral surface 35 of the vibration isolating rubber 35. is facing.

(Effect of the invention) As explained above, the present invention has one
A pair of vibration isolators 2 are provided, a main handle 1 supported at two points by the vibration isolator 2 is provided, and the main handle 1 is provided with a main handle 1 supported at two points on the vibration isolator 2.
An auxiliary handle 6 is provided, one end of which is fixed to and the other end of which is fixed between the pair of vibration isolators 2 of the main handle 1, and the pair of vibration isolators 2 have one end fixed to the power portion 3. a pair of anti-vibration rubbers 10, each of which is fixed and whose other end holds the main handle 1;
28, 35, and the pair of anti-vibration rubbers 10, 28,
The anti-vibration rubber 1 consists of cylindrical surfaces 25a, 32, and 34 such as metal walls facing the power portion 3 and fixed to either the power portion 3 or the main handle 1.
The above cylindrical surfaces 25a, 32, 34 of 0, 28, 35
The vertical cross section of the surface facing the cylindrical surface gradually increases from the main handle 1 side to the power section 3 side, or from the power section 3 side to the main handle 1 side.
2, 34 and the cylindrical surface 25a, 32, 3
4 and the convex tapered circumferential surfaces 22, 29, 36 that define asymptotic gaps 26, 33. Therefore, the shapes of the vibration isolating rubbers 10, 28, 35 can be simply formed. . Therefore, by adopting the shape of the present invention, precise molding can be easily performed, and precise products can be obtained at low cost.

In addition, the present invention has a power section 3 as shown in FIG.
A pair of vibration isolators 2 are provided in the main handle 1, and the main handle 1 is supported at two points by the vibration isolators 2. As a result, the vibrations transmitted to the main handle 1 interfere with each other between the vibration isolators 2, so it is possible to effectively obtain the effect that the load increases quadratically as the deflection increases. Even if the number 3 is large, the work can be performed in a stable state.

Furthermore, the present invention provides an auxiliary handle 6 having one end fixed to the main handle 1 and the other end fixed between the pair of vibration isolators 2 of the main handle 1.
, the auxiliary handle 6 can be fixed to the main handle 1 to which vibrations are not transmitted by the vibration isolator 2, and the device can be supported with both hands and worked without vibration.

Furthermore, as shown in FIGS. 3 to 6, the vibration isolating device 2 of the present invention includes a pair of vibration isolating rubbers 10, 28, each having one end fixed to the power portion 3 and the other end holding the main handle 1. 35, the main handle 1 can be supported in a more stable state by holding the main handle 1 from both sides. Therefore, according to the present invention, even if the power section 3 is large-sized, a sufficient support structure and vibration-proofing effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a left side partial view of a chain saw to which the present invention is applied, Fig. 2 is a front view as seen from the - arrow in Fig. 1, Fig. 3 is an enlarged cross-sectional view of Fig. 1, Figs.
6 are drawings corresponding to FIG. 3 to show another embodiment, and FIGS. 7, 8, and 9 are drawings corresponding to FIG. 3 to show a conventional structure. . 1... Handle (main handle), 2... Vibration isolator, 3... Power part, 6... Auxiliary handle, 10
... Vibration-proof rubber, 11 ... Crank case (metal wall), 22 ... Convex tapered outer peripheral surface, 25 ... Hole,
25a...Cylindrical surface, 26...Gap.

Claims (1)

[Scope of utility model registration request] A pair of vibration isolators are provided in the power portion, a main handle supported at two points is provided on the vibration isolator, one end of which is fixed to the main handle, and the other end of the vibration isolator is fixed to the main handle. The pair of vibration isolators include a pair of vibration isolators each having one end fixed to the power section and the other end sandwiching the main handle; a cylindrical surface such as a metal wall that faces the vibration isolating rubber and is fixed to either the power part or the main handle, and the surface of the vibration isolator that faces the cylindrical surface has a vertical cross section. gradually approaches the cylindrical surface from the main handle side to the power section side or from the power section side to the main handle side, and defines an asymptotic gap that smoothly extends parabolically with the cylindrical surface. A vibration isolator for a portable work machine characterized by comprising a peripheral surface.