JP2002295576A - Damping device for portable agricultural machine with a drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain engine vibration from transferring to operator's hands when an engine mower is used. SOLUTION: A damping device 22 for an engine mower has a rigid housing 24, a collision mass 34 provided floatingly in the housing 24 in the vibrating direction of a shaft 18 and collided with the housing 24 when vibrated, gaps S1, S2, and S3 formed between the housing 24 and the collision mass 34 to float the collision mass 34 in the vibrating direction, and a rubber elasticity object 36 formed on at least one of the hitting faces of the housing 24 and the collision mass 34. The damping device 22 is attached on the shaft 18 to restrain the shaft 18 from vibrating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to engines for mowers, hedge trimmers, pruners, lawnmowers, chainsaws, etc.
The present invention relates to a vibration damping structure of a portable agricultural machine equipped with a driving device such as a motor.

[0002]

2. Description of the Related Art It has been pointed out that in such mowing machines and the like, vibrations generated by a driving device such as an engine are transmitted to an operator's hand through a shaft or the like to cause a vibration obstacle. In a portable agricultural machine, a grip portion held by a worker is made of rubber to suppress transmission of vibration directly to the worker's hand.

[0003]

However, simply making the grip portion made of rubber cannot sufficiently prevent vibrations from being transmitted to the operator's hands. Therefore, various vibration damping devices are used for mowing machines and the like. Attempts have been made to mount them, but the conventional ones were too space-constrained or could not exhibit a sufficient damping effect.

[0004]

SUMMARY OF THE INVENTION The vibration damping structure of a portable agricultural machine with a driving device according to the present invention has been devised to solve such a problem. According to the first aspect of the present invention, there is provided a rigid contact portion provided so as to be integrally displaced with a vibrating portion of a portable agricultural machine having a driving device such as an engine such as a brush cutter and a motor.
A collision mass is provided in the vibration direction with respect to the corresponding portion and collides with the corresponding portion when vibrating, and is formed between the corresponding portion and the collision mass, and causes the collision mass to float in the vibration direction. A vibration suppression device having a gap for the vibration and an elastic body formed on at least one of the contact surfaces of the contact portion and the collision mass is mounted on the vibration portion to control the vibration portion. It is characterized by.

According to a second aspect of the present invention, in the first aspect, the vibration damping device is mounted on a shaft as the vibrating portion in a portable agricultural machine with a driving device.

According to a third aspect of the present invention, in the first aspect, the vibration damping device has a rigid housing having an idle chamber therein, and the housing constitutes the contact portion. The collision mass is movably accommodated in the floating chamber in the housing.

According to a fourth aspect of the present invention, in the third aspect, the housing is formed separately from the vibrating portion, and the housing is fixed to the vibrating portion.

According to a fifth aspect of the present invention, in any one of the first and second aspects, the contact portion has a rod shape or a tubular shape, and the collision mass has an annular shape. It is characterized by being loosely fitted to the outside.

[0009]

As described above, according to the present invention, a rigid contact portion provided in such a manner as to be integrally displaced with a vibrating portion in a portable agricultural machine with a driving device, and a vibration portion of the vibrating portion with respect to the contact portion. A vibration damping device having a collision mass provided in a floating state, a gap formed therebetween, and an elastic body interposed between the collision mass and the hit portion is mounted on the vibration portion, and the vibration The vibration of the section is suppressed.

This vibration damping device works as follows. That is, in the case of this vibration damping device, when the vibrating portion starts to vibrate, the contact portion is displaced integrally with the vibrating portion and starts to vibrate in synchronization with the vibrating portion. On the other hand, since the collision mass is in a floating state with respect to the hit portion in the vibration direction, that is, freely moves independently in the same direction with respect to the hit portion, it collides with the hit portion when the hit portion vibrates, and It acts to cancel the vibration, that is, the vibration of the vibrating part.

At this time, a kinetic energy is applied to the collision mass that collides with the hit portion in the opposite direction from the collision portion (thus, a part of the vibration energy of the collision portion is absorbed as the kinetic energy of the collision mass). Performs the movement in the opposite direction. Then, it again collides with the contact surface located at a position opposite to the first contact surface, and acts so as to cancel the vibration of the contact portion, that is, the vibration portion again.

The collision mass repeats the same motion in the opposite phase or a different phase from that of the hit portion to absorb the vibration energy of the hit portion and convert it to its own kinetic energy at every collision. Continue to hit the vibrating contact. Due to this energy absorption, the vibration energy of the vibrating part is attenuated, and the vibration is effectively suppressed.

If both the hit portion and the collision mass are made of a rigid body, a loud noise (collision sound) is generated at the time of collision. However, in the vibration damping device according to the present invention, since an elastic body such as rubber or resin is formed on at least one of the contact surfaces of the contact portion and the collision mass, there is no problem that large abnormal noise is generated at the time of collision, and Vibration energy is converted and absorbed into heat by the sliding wear at the time and the viscous behavior of the elastic body, that is, the vibration damping action of the elastic body works to promote the vibration damping of the vibrating part.

It is also conceivable to attach a dynamic damper to the vibrating section to suppress the vibration of the vibrating section.
This dynamic damper adds a damper mass to a vibrating portion via a spring. The natural frequency of an additional vibration system including the damper mass and the spring is determined by the natural frequency of the main vibration system (the natural frequency of the vibrating portion). By tuning to (), the resonance magnification of the vibrating part can be reduced and vibration can be suppressed.

However, the vibration damping by the dynamic damper only exerts an effect on vibration of a single resonance frequency, and cannot effectively prevent resonance of another frequency. That is, it is not effective for resonance at a plurality of frequencies. Moreover, in the case of the dynamic damper, there is a problem that another resonance is newly generated before and after the resonance point. In addition, when a rubber elastic body is used as the spring, the spring constant of the rubber elastic body changes depending on the temperature, so that the temperature dependency of the vibration damping characteristics is high, and the vibration damping efficiency decreases at high or low temperatures.

Furthermore, the dynamic damper requires a large mass as the damper mass (10% of the vibrating member).
% Mass), the overall weight of the device becomes heavy, the required installation space is large, and the direction in which vibration can be damped is determined, and various problems such as ineffectiveness in multi-directional vibration are not achieved. Is inherent.

However, in the vibration damping device of the present invention, the collision mass is provided so as to be independently movable, and the collision mass is moved in a phase opposite to or different from that of the vibration portion to be damped. Part) and absorbs and attenuates vibration energy, so there is no particular frequency dependency.
Vibration can be suppressed over a wide frequency range, and it is easy and simple to take collision directions in multiple directions, and vibrations in multiple directions can be suppressed, and the dependence on temperature is small, Exhibits good vibration damping effect over a wide temperature range from high to low. In addition, the mass required for the collision mass is light and sufficient (a mass of about 5% of the vibration member is sufficient), and the space required for the entire apparatus is small and compact, and it can be easily mounted on the vibration part. Has features.

FIG. 1 schematically shows an embodiment of a vibration damping device according to the present invention in comparison with a dynamic damper. In FIG. 1, reference numeral 1 denotes the vibration damping device, and reference numeral 2 denotes a dynamic damper. . Reference numeral 3 denotes a collision mass in the vibration damping device 1, 4 denotes an elastic body formed on the outer peripheral surface of the collision mass 3, that is, a contact surface, 5 denotes a housing forming a contact portion, and 6 denotes a damper mass in the dynamic damper 2. , 7 indicate a spring (rubber), and 8 indicates a vibration member.

FIG. 1B shows the dynamic damper 2 when the vibration damping device 1 is mounted on the vibration member 8.
Are shown in comparison with the case where they are mounted and the case where they are not mounted. However, in FIG. 1B, c shows a case where the vibration damping device 1 is mounted, b shows a case where the dynamic damper 2 is mounted, and a shows a case where neither of them is mounted.

As can be seen from the vibration damping characteristics shown in FIG. 1B, when the dynamic damper 2 shown in FIGS. 1A and 1B is mounted, in a specific frequency region (here, the region on the high frequency side). Although resonance can be suppressed, another new resonance is generated before and after the resonance point, and no effect is exerted on the resonance on the lower frequency side, but the vibration damping shown in FIGS. In the case of the device 1, the effect is exhibited on both the high frequency side and the low frequency side, and further, a phenomenon that another new resonance occurs before and after the resonance point does not occur. As is clear from the above, it can be seen that the vibration of the vibrating part can be satisfactorily suppressed by mounting the vibration damping device of the present invention on the vibrating part of the portable agricultural and industrial machine with a drive device.

In the present invention, the rigid contact portion can be made of a metal such as iron or aluminum alloy, a hard resin, or another hard material. Further, the collision mass itself can be constituted by an elastic body such as rubber or resin. However, in this case, it is desirable to constitute a high specific gravity rubber, a high specific gravity resin, or the like in which metal powder or the like is mixed therein.
When the collision mass is made of an elastic material, it can be made into a foam. However, in order to achieve more effective vibration suppression, it is desirable that the collision mass be made of a metal such as iron, an aluminum alloy, or lead.

In the present invention, the gap has an important meaning in making the collision mass most effectively collide against the hit portion, and in this sense, the gap is formed in a range of 0.05 to 2.0 mm. Desirable, more desirably 0.2 to
The range is 1.0 mm.

In the present invention, rubber and resin can be used as the elastic body. Here, as the rubber, for example, various rubbers such as diene rubber such as NR, SBR and BR, EPDM rubber, urethane rubber and silicon rubber can be used. As the resin, for example, a thermoplastic resin such as polypropylene or polyamide, a polyolefin, urethane, a polyester-based thermoplastic elastomer or the like can be used.

Here, the elastic body may be bonded and fixed to the collision surface or the contact surface of the contact portion by vulcanization or the like, or may be formed on the contact surface in a non-adhered state.

In the present invention, a vibration damping device can be mounted on a shaft which is a transmission path of the vibration generated by the driving device. By doing so, it is possible to most effectively suppress the transmission of the vibration generated by the driving device such as the engine to the hands of the operator.

In the present invention, a rigid housing having a floating chamber therein is provided in the vibration damping device so that the housing constitutes the contact portion, and the collision mass is accommodated in the floating chamber in a floating state. (Claim 3).

Further, in this case, the whole vibration damping device can be mounted on the vibrating portion by forming the housing separately from the vibrating portion and fixing the housing to the vibrating portion. ). By doing so, the vibration damping device can be mounted very easily at a necessary place afterwards.

In the present invention, the hitting portion may be formed in a rod shape or a tubular shape without providing the above-described housing in the vibration damping device, and an annular collision mass may be loosely fitted to the outside thereof. 5). Also in this case, the vibrating portion can be favorably damped by the collision action of the collision mass with the contact portion.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a mower with an engine will be described in detail with reference to the drawings. In FIG. 2, reference numeral 10 denotes a mowing machine with an engine (a portable agricultural machine with a driving device), and reference numeral 12 denotes an engine as a driving device,
4 is a rotary blade, and 16 is a cover of the rotary blade 14.
Reference numeral 18 denotes a shaft on which rubber handles 20 are provided at two places.

Numeral 22 denotes a vibration damping device mounted on the shaft 18, and its specific configuration is shown in FIG. As shown in the figure, the vibration damping device 22 has a cylindrical metal housing 24 in which both ends in the axial direction are closed. The housing 24 is divided into upper and lower halves, and a flange portion 26 is provided on each of the half-cylindrical half bodies 24A. The body 24A is fastened and is fixed to the shaft 18 at the same time.

A cylindrical floating chamber 32 is formed inside the housing 24, in which a cylindrical metal collision mass 34 is movable in both the direction perpendicular to the axis of the shaft 18 and the axial direction. Is housed. That is, the rubber elastic body 3 extends over the entire outer surface of the collision mass 34 having the cylindrical shape.
6 are formed in a covered state (they may be integrally fixed by vulcanization bonding or may be simply covered), and the layer of the rubber elastic body 36, the inner surface of the housing 24, and the shaft 18, the gaps S ₁ , S ₂ , S
₃ are formed. The rubber elastic body 36 may not be coated over the entire outer surface of the collision mass 34 (the entire contact surface of the collision mass 34), and may be a part of the rubber elastic body 36, for example, only at both ends of the cylindrical shape or in the vicinity thereof. good.

[0032] The gap S is more of a gap _{S 2,} in this example
₃ , the collision mass 34, more specifically, the rubber elastic body 36 on its outer surface collides with the inner surface of the housing 24 when vibrating in the direction perpendicular to the axis, and the shaft 18
Does not collide with However by reversing the size of the gap S ₂ and S _3, that is, the gap S ₃ is made smaller than the gap S _2, the collision mass 34 can also be made so as to collide against the outer surface of the shaft 18. In this case, the housing 2
Reference numeral 4 does not function as an original contact portion, but merely serves as a cover for covering the collision mass 34 from the outside, and the shaft 18 functions as a contact portion.

In the case of the vibration damping device 22 of this embodiment, the shaft 18
When the housing starts to vibrate, the housing 24 is displaced integrally therewith and starts to vibrate in synchronism with the shaft 18, but one of the collision masses 34 is freely floating in the vibration direction with respect to the housing 24 and is free independently. Housing 2 to move
4, the collision mass 34 collides against the housing 24 in the vibration direction, and the vibration of the housing 24,
Acts to cancel the vibration of

At this time, the collision mass 34 is
Kinetic energy is applied from the
Performs the movement in the opposite direction. Then, it again collides with the contact surface located at a position opposite to the first contact surface, and acts to cancel the vibration of the shaft 18.

Thereafter, the collision mass 34 repeats the same motion in a phase opposite to or different from that of the housing 24 to absorb the vibration energy of the housing 24, that is, the shaft 18 at each collision, and to transfer the same to its own motion. Convert to energy. As a result, the vibration energy of the shaft 18 is attenuated due to the energy absorption by the sliding friction at that time, and the vibration is effectively suppressed.

In the vibration damping device 22 of the present embodiment, since the layer of the rubber elastic body 36 is formed on the entire outer surface of the collision mass 34, there is no problem that a loud noise is generated at the time of collision. The vibration damping action of the elastic body 36 promotes the vibration damping of the shaft 18.

Further, unlike the dynamic damper, the vibration damping device 22 of this embodiment has no particular frequency dependence, can suppress vibration over a wide frequency range, has a small dependence on temperature, and has a high temperature to a low temperature. Good vibration damping effect over a wide temperature range. In addition, since the required mass of the collision mass 34 is light and sufficient, it has various features such as a small space required for the entire device and a compact size, and easy mounting on the shaft 18.

In this example, the vibration generated by the engine 12 is attached to the operator's hand because the vibration generated by the engine 12 is mounted on the shaft 18 which is a path for transmitting the vibration generated by the engine 12 to the hand (grip) 20. Can be suppressed most effectively.

In this embodiment, a housing 24 forming a contact portion is provided.
Is fixed to the shaft 18 separately from the shaft 18, and the whole vibration damping device 22 is mounted on the shaft 18. Therefore, the vibration damping device 22 can be mounted very easily at a necessary place by retrofitting. be able to.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the housing 24 is omitted, and an impact mass 34 having a cylindrical shape (annular shape) is provided on the outer side of a rod-shaped shaft 18 serving as a contact portion. This is an example in which the collision mass 34 is caused to collide with the outer surface of the shaft 18 by loose fitting. Also in this example, the shaft 18 can be favorably damped by the collision action of the collision mass 34 against the shaft 18.

However, the shaft 18 has a predetermined interval in the axial direction.
A metal disk 38 is fixed at a distance, and is fixed in the axial direction.
The collision mass 34 collides against the disks 38 to control the vibration.
Works. The disk 38 functions as a positioning member.
And the gap S ₁About collision ma
No clearance to allow movement of thread 34 in the direction perpendicular to the axis
You can keep it.

FIG. 5 shows still another embodiment of the present invention. In this embodiment, a handle 40 is attached to a shaft 18 and a rubber handle 20 is provided at the tip of the handle 40. Other points are the same as those of the embodiment of FIGS. However, it is of course possible to configure the vibration damping device 22 as shown in FIG.

The embodiment of the present invention has been described in detail above, but this is merely an example. For example, the present invention can be applied to hedge trimmers, pruners, lawn mowers, chainsaws and the like other than the mower, or to those having a motor as a driving device in some cases. Is also possible. The present invention can be configured in various modified forms without departing from the gist of the invention, such as the rubber elastic body 36 can be formed of resin.

[Brief description of the drawings]

FIG. 1A is a diagram schematically illustrating an embodiment of a vibration damping device according to the present invention in comparison with a dynamic damper. (B): It is explanatory drawing of the effect of the vibration damping device of (A).

FIG. 2 is an overall view showing a mowing machine with an engine, which is an example of an object to which the present invention is applied, with a vibration damping device mounted.

FIG. 3 is a diagram showing a specific configuration of the vibration damping device of FIG. 2;

FIG. 4 is a diagram showing a configuration of a vibration damping device according to another embodiment of the present invention.

FIG. 5 is an overall view showing a mowing machine with an engine according to another embodiment to which the present invention is applied, with a vibration damping device mounted.

[Explanation of symbols]

10 with the engine mowers (driving device with portable & M unit) 12 engine (driving device) 18 Shaft 22 damping device 24 housing 32 idler chamber 34 collides mass 36 rubber elastic body S _{1, S} 2, _{S 3} Clearance

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2B083 AA01 AA02 BA02 CA07 CA11 CA14 CA27 DA02 EA08 GA05 HA54 3J048 AA02 AD06 BA25 BF02 DA06 EA11

Claims (5)

[Claims] 1. A rigid contact portion provided in such a manner as to be integrally displaced with a vibrating portion of a portable agricultural machine having a driving device such as an engine and a motor such as a brush cutter, and a movable portion in a vibration direction with respect to the corresponding portion. Provided, a collision mass that collides with the corresponding portion during vibration, a gap formed between the relevant portion and the collision mass, and a gap for allowing the collision mass to float in the vibration direction, and a contact portion and the collision mass Characterized in that a vibration damping device having an elastic body formed on at least one of the contact surfaces is mounted on the vibrating portion so as to dampen the vibrating portion. Swing structure. 2. The vibration damping structure for a portable agricultural machine with a driving device according to claim 1, wherein the vibration damping device is mounted on a shaft as the vibrating portion in the portable agricultural machine with a driving device. 3. The vibration damping device according to claim 1, wherein the vibration damping device has a rigid housing having an idle chamber therein, and the contact portion is formed by the housing.
A vibration damping structure for a portable agricultural machine with a driving device, wherein the collision mass is movably accommodated in the floating chamber in the housing. 4. A vibration damping structure for a portable agricultural machine with a driving device according to claim 3, wherein said housing is separate from said vibrating portion, and said housing is fixed to said vibrating portion. . 5. The hitting portion according to claim 1, wherein the contact portion has a rod shape or a tubular shape, and the collision mass has an annular shape, and the collision mass is loosely fitted to the outside of the corresponding portion. A vibration damping structure for a portable agricultural machine with a driving device.