JPH0320Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a mower that is installed between the transmission shaft of a motorized brush cutter used for cutting weeds or shrubs, and the shaft pipe that accommodates the transmission shaft. The present invention relates to a vibration isolating device for a brush cutter that suppresses vibration of a shaft pipe.

(Prior Art) An overview of a motorized brush cutter that cuts weeds, shrubs, etc. by rotating a cutting blade using a two-stroke engine will be explained with reference to FIG. As shown in the figure, this motorized brush cutter is configured such that the rotation of an engine 2 rotates a cutting blade 3 provided at the tip of a pipe 1 via a clutch provided within a pipe joint 1a. The operator holds the machine by hanging the shoulder belt (not shown) attached to the locking member 5 over his shoulder, grips the rubber grip 4 with one hand, and holds the handle 6 with the other hand to hold the cutting blade 3. Reap while pressing the material against the material to be reaped.

In order to prevent the vibrations of the engine 2 from being transmitted to the hands of the worker during the above-mentioned reaping work, and to prevent occupational diseases such as white wax disease, a rubber gasket is used in the pipe joint 1a to absorb vibrations. .

This conventional vibration absorbing gasket was developed in 1983.
As disclosed in Japanese Patent No. 1133, a thin vibration isolator 4 molded to match the outer shape of a clutch housing 1 which is divided into two parts is interposed between a clamp fitting 5 which is divided into two parts.

This prevents the vibrations of the engine mounted on the clutch housing 1 from being transmitted to the pipe held by the operator by utilizing the cushioning effect of the vibration isolating rubber body 4.

Further, the vibration-absorbing packing disclosed in Japanese Utility Model Application Publication No. 59-163331 has two protrusions a and b on the outer surface of the clutch case C, and shock absorbers 7 and 8 are provided on the protrusions a and b, respectively. The outer tube holder 9, which is split into two, is fitted so as to wrap around the outer periphery of the buffer bodies 7 and 8, and the buffer 7 is inserted between the outer surface of the clutch case C and the inner surface of the outer tube holder 9. , 8 are held together.

This vibration-absorbing packing absorbs vibrations in the axial direction of the outer tube holder 9 by bending the buffers 7 and 8, and absorbs vibrations in the diametrical direction of the outer tube holder 9. The torque of the outer tube holder 9 is absorbed by the compression of the buffer bodies 7 and 8, and the protrusions a and b provided on the outer periphery of the buffer bodies 7 and 8 absorb the torque of the outer tube holder 9.
The material is absorbed by bending.

Furthermore, when a packing having a flange 8 provided at one end of the cylindrical portion 7 is used as shown in FIG. is mainly absorbed by bending the flange.

(Problem to be solved by the invention) It is known that when using a shock absorber such as rubber to absorb vibrations, the larger the mass of the shock absorber, the greater the buffering effect. In addition, for motorized brush cutters, it is important that engine vibrations are not transmitted to the pipe, but on the other hand, a sense of unity between the pipe and engine is required in terms of cutting performance.

First of all, the one disclosed in Publication of Utility Model Publication No. 1133/1983 had a problem in that a thin packing was attached to follow the outer shape of the crankcase, so its mass was not sufficient and it could not absorb vibrations sufficiently. be. Next, in the method disclosed in Japanese Utility Model Application Publication No. 59-163331, the mass of the packing is sufficiently large and it is possible to sufficiently absorb vibrations, but the absorption of vibrations in the axial direction of the outer tube holder and in response to torque is difficult due to the bending of the packing. Since the pipe is used, there is no sense of unity between the pipe that the worker holds and the engine. For this reason, when mowing, the mowing blade must be supported only by the strength of the arm to prevent it from being repelled from the object to be mown, resulting in poor mowing performance. In addition, in the case of the gasket shown in Figure 22, the structure to prevent the gasket from coming off due to vibration is complicated, making assembly difficult and causing problems in terms of productivity, and the gasket does not come off due to vibration. If the packing material is baked in this way, the packing material will change in quality and its vibration absorbing function will deteriorate, which is a problem.

The present invention provides a vibration isolating device for a brush cutter that has a sufficiently large mass of a shock absorber, provides a sense of unity between the pipe and the engine, improves mowing performance, and is easy to assemble.

(Means for Solving the Problems) A means according to the present invention for solving the above problems is to provide protrusions on both sides of the vibration isolating rubber, and to provide protrusions on one side of the vibration isolating rubber at the rear and end portions of the bearing case. Protrusions are provided so as to engage with the protrusions that have been
A groove is formed on the inner surface of the two-split main pipe holder, into which the outer periphery of the vibration-proofing rubber fits, and a recess into which a projection provided on the other surface of the vibration-proofing rubber engages is provided. That is.

(Function) Since the present invention is constructed in this way, the protrusion provided on one side of the protrusions provided on both sides of the vibration isolating rubber is engaged with the protrusion provided on the rear surface of the bearing case and the protrusion provided on the end of the bearing case. Attach the anti-vibration rubber to the bearing case, fit the outer periphery of the anti-vibration rubber into the groove provided on the two-split main pipe holder, and attach the protrusion provided on the other side of the anti-vibration rubber to the main pipe holder. By engaging and assembling the anti-vibration rubber in the recess, the rubber is sandwiched between the end face and rear face of the protrusion provided on the bearing case, the bottom face of the recess of the main pipe receiving fitting, and the side face of the recessed groove. As a result, vibrations in the axial direction of the bearing case are absorbed by compressing the anti-vibration rubber, and vibrations in the diametrical direction of the main pipe bracket are absorbed between the inner peripheral surface of the groove provided in the main pipe bracket and the bearing case. The vibration isolator is compressed and absorbed, and vibrations in the torque direction are absorbed by the engagement between the protrusions on the antivibration rubber, the protrusions on the bearing case, and the recesses on the main pipe holder. It is absorbed by the shearing force acting on the protrusions provided on the rubber. In this way, vibration is absorbed by the compression and shear force of the vibration isolating rubber, thereby providing a sense of unity between the main pipe receiving fitting and the bearing case.

(Example) An example of the present invention will be described below. First, the outline of the vibration isolator 10 will be explained in FIG. 1. The shaft portion 12a of the transmission shaft member 12 is equipped with a clutch mechanism to which the power of an engine (not shown) is transmitted.
is rotatably supported by a bearing case 14 via a bearing 13. Two anti-vibration rubbers 16 and 17 are attached to the outer periphery of the bearing case 14, and the anti-vibration rubbers 16 and 17 are sandwiched between the two main pipe brackets 15, and the main pipe bracket 15 is attached to the bearing case 14. It will be installed. The pipe 1 is press-fitted into the tip of the main pipe receiving fitting 15, and a power transmission shaft 11 having one end fixed to a transmission shaft member 12 is inserted into the pipe 1.

In FIG. 2, the bearing case 14 has a cylindrical portion 14a on which a vibration-isolating rubber 16 is mounted and a cylindrical portion 14b on which a vibration-isolating rubber 17 is mounted. 21 is provided, and protrusions 18 and 19 are provided at the ends of the cylindrical portion 14b.
Further, the outer diameter of the cylindrical portion 14a is larger than the outer diameter of the cylindrical portion 14b and larger than the virtual circle connecting the tips of the protrusions 18 and 19. These protrusions 18,1
As shown in FIG. 3, 9, 20, and 21 are provided facing each other at 90 degrees to the center line of the bearing case 14, and one protrusion 18 and 20 has a rectangular shape. The protrusions 19 and 21 are provided in the form of two protrusions facing each other and protruding from each other. These protrusions 18, 19,
20 and 21 are integrally molded with the bearing case 14 as shown in FIG.

The main pipe holder 15 is divided into two parts as shown in FIGS. 5 and 6. Figures 5 to 11 show one side of the main pipe holder 15 of the two-split main pipe holder 15.
It shows a. Reference numerals 24 and 27 are screw holes for fastening the main pipe holder 15, which has been split into two, with the half-split surface 22. As shown in FIG. 7, the main pipe holder 15 is formed with a groove 25 into which the vibration isolating rubber 16 described in FIG. Facing this groove 25, three recesses 28 are provided in the two-split one-side main pipe receiving fitting 15a (see also FIGS. 8 and 11).
Three recesses 29 are also provided in the groove 26 (see also FIG. 10). As shown in FIG. 9, the screw hole 27 is formed so as to pass through the end of the one-sided main pipe receiving fitting 15a.

As shown in FIGS. 12 to 14, the other one-side outer pipe holder 15b has the same inner surface shape as the one-side main pipe holder 15a shown in FIG.
A bolt hole 31 is drilled at a position corresponding to the screw hole 24 drilled in the one side main pipe receiving fitting 15a, and a bolt hole 32 is bored at a position corresponding to the screw hole 27. 3
3 and 34 are seat surfaces. Further, pipe fitting holes 2 are provided on the sides of the cylindrical parts 14a and 14b into which the pipe 1 is fitted.
3 (see Fig. 7) into which a threaded part (not shown) is screwed to fix the position of the pipe 1 fitted to the pipe 1.
is provided.

Next, the vibration isolating rubber 16 in FIG. 1 will be explained. 15 to 17, the external shape of the vibration isolating rubber 16 as a whole has a protruding cross shape, and the imaginary circle connecting its tips approximately corresponds to the diameter of the groove 25 shown in FIG. Thickness is groove 2
The width approximately corresponds to the width of 5. No. 15 of anti-vibration rubber 16
As shown in FIG. 16, two protrusions 36 are provided facing each other on the surface shown in the figure.
The spacing 6 is determined so that the protrusion 20 shown in FIG. 3 can be fitted therein. Further, the width of the protrusion 37 is determined so that it fits between the two protrusions 21 shown in FIG. On the other hand, in FIG. 17 showing the back side of FIG. 15, a protrusion 38 that fits into the recess 28 shown in FIG. 7 is formed on the back side (see also FIG. 16).

Next, the vibration isolating rubber 17 in FIG. 1 will be explained. In FIGS. 18 to 20, the external shape of the anti-vibration rubber 17 is in the shape of a protruding cross as a whole, and the imaginary circle connecting its tips approximately corresponds to the diameter of the groove 26 shown in FIG. 7, and its thickness is groove 26
It roughly matches the width of . As shown in FIG. 19, two protrusions 36' are provided on the surface of the anti-vibration rubber 17 shown in FIG. 18, facing each other.
The interval 6' is determined so that the protrusion 18 shown in FIG. 3 can be fitted therein. Further, the width of the protrusion 37' is determined so that it fits between the two protrusions 19 shown in FIG. On the other hand, the second figure showing the back side of Figure 18
In Figure 0, there is a recess 2 shown in Figure 7 on the back side.
A protrusion 38' is formed which fits between the holes 9 (see also FIG. 19). This anti-vibration rubber 17 is cut at a cutting portion 39. In this way, protrusions 36 and 3
The reason for changing the shape of 7 is to take into consideration the mass of the rubber when absorbing vibrations in the torque direction.
If the mass is too large, the sense of unity between the pipe and the engine side will be impaired, and if the mass is too small, vibrations in the torque direction will not be absorbed. Regarding the vibration isolating rubber 17, the shapes of the protrusions 36' and 37' are changed for the same reason.

The operation of this embodiment configured as above will be explained next. First, to explain the ease of assembly, in a state where the transmission shaft portion 12 is pivotally supported by the bearing case 14 via the bearing 13, the anti-vibration rubber 16 is inserted from the protrusion 19 side of the bearing case 14 between the protrusions 21 of the bearing case 14. The bearing case 1 is fitted between the protrusions 3 of the anti-vibration rubber 16 and the protrusions 36 provided on the anti-vibration rubber 16
Insert it so that the protrusion 20 of No. 4 fits into it.

Next, the protrusion 1 is provided at the end of the bearing case 14 so that the anti-vibration rubber 17 opens from the cut portion 39.
The bearing case 14 is mounted by fitting the protrusions 37' of the vibration isolating rubber 17 between the protrusions 36' of the vibration isolating rubber 17 and fitting the protrusions 18 of the bearing case 14 between the protrusions 36' of the vibration isolating rubber 17.

When installing the anti-vibration rubbers 16 and 17 in this manner, insert the anti-vibration rubber 16 with the surface shown in FIG. 15, and the anti-vibration rubber 17 with the surface shown in FIG. 18. I try to put the one that is difficult to fit in first. Next, the two-split main outer tube holder 15 is attached so as to sandwich the vibration isolating rubbers 16 and 17. At the time of this installation, the protrusion 38 of the anti-vibration rubber 16
Then, the vibration isolating rubber 17 is attached by fitting the protrusions 38' into the recesses 28 and 29 of the main outer tube holder 15. And bolt hole 3 of one side main pipe holder 15b
Insert bolts into holes 1 and 32, and attach one side main pipe holder 15.
The two halves of the main pipe holder 15 are screwed into the screw holes 24 and 27 of a, and the assembly is completed as shown in FIG.

Next, vibration isolation will be explained. First, as shown in FIG. 1, vibration in the axial direction of the main pipe receiving fitting 15 is performed as follows. In other words, the protrusion 3 of the anti-vibration rubber 16
6, 37 and the protrusions 20, 21 provided on the rear surface 14c of the bearing case 14 are engaged with each other, so that the surface shown in FIG.
This means that the end surfaces 20a and 21a of 21 are in contact with both of them. On the other hand, since the protrusion 38 of the anti-vibration rubber 16 and the recess 28 provided in the main pipe holder 15 are engaged, the surface of the anti-vibration rubber 16 shown in FIG. 25a and recess 28
This means that the bottom surface 28a of is in contact with both of them. Therefore, both sides of the anti-vibration rubber 16 (the surfaces shown in FIGS. 15 and 17) are exposed to the protrusions 20, 2.
1 end surfaces 20a, 21a and rear surface 14c (second
), the side surface 25a of the groove 25 and the recess 2
The vibration isolating rubber 16 is compressed against the vibration in the axial direction of the bearing case 14, and the vibration is absorbed by the compression of the vibration isolating rubber 16. be done.

Similarly, regarding the anti-vibration rubber 17, the anti-vibration rubber 1
Since the protrusions 36' and 37' of 7 and the protrusions 18 and 19 provided at the end of the bearing case 14 are engaged with each other, the surface shown in FIG. 18a and 19a are in contact with each other. On the other hand, the protrusion 38' of the anti-vibration rubber 17
and the recess 29 provided in the main pipe holder 15 are engaged with each other, so that the surface of the vibration isolating rubber 17 shown in FIG. 29a are in contact with each other. Therefore, both sides of the anti-vibration rubber 17 are sandwiched between the end surfaces 18a and 19a of the protrusions 18 and 19, the side surface 26a of the groove 26, and the bottom surface 29a of the recess 29, and the anti-vibration rubber 17 is sandwiched between the end surfaces 18a and 19a of the projections 18 and 19, the side surface 26a of the groove 26, and the bottom surface 29a of the recess 29. It is compressed against vibrations in the axial direction of the case 14, and the vibrations are absorbed by compression of the vibration isolating rubber 17.

Next, vibration absorption in the torque direction will be explained.
This vibration in the torque direction is caused by the engagement of both protrusions. That is, the protrusions 36 and 37 provided on the anti-vibration rubber 16 and the rear surface 1 of the bearing case 14
4c and the projection 38 provided on the vibration isolating rubber 16 and the recess 28 provided on the main pipe holder 15, the projection 36 provided on the vibration isolating rubber 16 is , 37, and 38 receive shearing force in response to the force in the torque direction, and vibrations in the torque direction are absorbed by this shearing force.

Similarly, the anti-vibration rubber 17 also has an engagement between protrusions 36' and 37' provided on the anti-vibration rubber 17 and protrusions 18 and 19 provided on the end of the bearing case 14, and a protrusion 38 provided on the anti-vibration rubber 17. ' and main pipe bracket 15
The force in the torque direction acts as a shearing force on the protrusions 36', 37', 38' of the vibration isolating rubber 17 by engagement with the recess 29 provided in the vibration isolating rubber 17, and the vibration in the torque direction is absorbed by this shearing force.

Next, absorption of vibration in the diametrical direction of the main pipe receiving fitting 15 will be explained. This vibration in the diametrical direction is caused by the outer periphery of the vibration isolating rubbers 16, 17 coming into contact with the inner peripheral surfaces 25b, 26b of the grooves 25, 26 provided in the main pipe holder 15, and the inner periphery 16a of the vibration isolating rubbers 16, 17. ,17
a indicates the cylindrical portions 14a, 14 of the bearing case 14;
Since the anti-vibration rubbers 16 and 17 are fitted in
b, 26b, and vibrations in the diametrical direction are absorbed by compressing the vibration isolating rubbers 16, 17.

In this way, vibrations in the axial and diametrical directions are absorbed by compression of the vibration isolating rubbers 16 and 17, and vibrations in the torque direction are absorbed by the protrusions 36 provided on the vibration isolators 16 and 17.
Since the shearing forces of 37, 38, 36', 37', and 38' are absorbed, there is a sense of unity between the main pipe receiving fitting 15 and the bearing case 14. Also, vibration-proof rubber 16,
It is also possible to freely determine the mass of 17.

(Effects of the invention) As detailed above, according to the invention, projections are provided on both sides of the anti-vibration rubber, the projections provided on one of the surfaces engage with the projections provided on the bearing case, and the projections provided on the other surface engage with the projections provided on the bearing case. The protrusion is made to engage with the recess provided in the main pipe holder, and the outer periphery of the vibration isolating rubber is fitted into the groove formed in the main pipe holder.
The vibration isolating rubber is sandwiched between the end and rear surface of the protrusion of the bearing case and the bottom surface of the recess and the side surface of the recessed groove of the main pipe holder. As a result, vibrations in the axial direction and diametrical direction of the bearing case can be absorbed by compressing the vibration isolating rubber, and vibrations in the torque direction can be absorbed as shearing force of the protrusions provided on the vibration isolating rubber. A sense of unity between the bracket and the bearing case can be obtained. This helps prevent occupational diseases and improves mowing performance through a sense of unity.

[Brief explanation of drawings]

1 to 17 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of the vibration isolator, and FIG.
The figure is a plan view showing the external shape of the bearing case.
The figure is the left side view of Figure 2, and Figure 4 is A-A of Figure 3.
Fig. 5 is a plan view showing the outer shape of one of the main pipe holders divided into two, Fig. 6 is a left side view of Fig. 5, and Fig. 7 is a front view of the main pipe holder. ,
Fig. 8 is a right side view of Fig. 7, Fig. 9 is a sectional view along the - line of Fig. 5, and Fig. 10 is a - of Fig. 7.
11 is a sectional view taken along the line XI-XI in FIG. 7, FIG. 12 is a plan view showing the outer shape of the other side of the main pipe holder split into two, and FIG. 13 is a sectional view taken along line XI-XI in FIG. Figure 12 is the front view, Figure 14 is the - of Figure 12.
15 is a front view of the anti-vibration rubber seen from the bearing case engagement side, FIG. 16 is a plan view of FIG. 15, and FIG. 17 is a rear view of FIG. 15.
18 is a front view of the anti-vibration rubber seen from the bearing case engaging side, FIG. 19 is a plan view of FIG. 18, and FIG. 20 is a rear view of FIG. 18. FIG. 21 is an explanatory perspective view showing the entire brush cutter, and FIG. 22 is a perspective view showing a conventional vibration isolating rubber. 10... Vibration isolator, 14... Bearing case, 16, 17... Vibration isolator rubber, 18, 19, 2
0,21...Protrusion, 25,26...Concave groove, 28,
29... recess, 36, 37, 38... protrusion, 3
6', 37', 38'...protrusion, 39...notch.

Claims (1)

[Scope of utility model registration request] Protrusions are provided on both sides of the anti-vibration rubber, protrusions are provided on the rear surface and end of the bearing case to engage with the protrusions provided on one side of the anti-vibration rubber, and the inner surface of the two-split main pipe holder is A vibration isolating device for a brush cutter, characterized in that a concave groove is formed into which the outer periphery of the vibration isolating rubber fits, and a recess into which a protrusion provided on the other surface of the vibration isolating rubber engages is provided.