JPS5946751B2 - Anti-vibration handle device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vibration-proof bundle device, which is particularly used as a vibration-proof hand-held vibration tool such as a hand-held electric glider or an electric drill, and which does not impair the operability of the bundle. The present invention relates to a vibration-proof nodle device that can block the transmission of harmful vibrations from a vibrating tool to a bundle.

Conventionally, anti-vibration measures for handles attached to hand-held vibrating tools such as hand-held electric gliders and electric drills have been achieved by interposing anti-vibration rubber etc. between the vibrating tool and the handle. Many methods are used to isolate vibrations.

The principle of such a vibration isolation type vibration isolation bundle and its problems will be described below.

A vibration isolation bundle can be represented by a mechanical model shown in FIG.

In the figure, 1 is the amplitude U1, the excitation frequency ω, and the vibration displacement u”
The vibration source is a vibrating tool that vibrates at Usinωt, and a damper 4 with a viscous resistance coefficient C of a spring 3 as a spring constant is interposed in parallel between the vibration source 1 and a bundle 2 with a mass M. .

Here, the spring 3 and the damper 4 correspond to anti-vibration rubber or the like.

At this time, the vibration displacement of bundle 2 is x = Xsin (
ωt + a) (X is the amplitude, α is the phase angle), □
The amplitude X of bundle 2 and the vibration source 1.

In Figure 2, the damping rate ζ is constant, but the natural frequency is ω
n1, ωf12 (ωnl'>ω.

Two different types of curves are drawn.

In the figure, the curve a indicates the natural frequency ωn1, and the curve a has the natural vibration as a vibration isolation region, which is indicated by diagonal lines in FIG.

As is clear from FIG. 2, the smaller the natural frequency, the wider the vibration isolation area and the higher the vibration isolation effect.

General anti-vibration bundles are made based on this idea, but it is necessary to increase the natural frequency or make the bundle 2 heavier.

However, if the spring 3 is weakened, the operation of the nozzle 2 becomes soft, and the vibrating tool (vibration source 1) becomes unstable, which is dangerous.

In addition, it is not preferable to make the handle 2 heavy because the hand-held tool needs to be lightweight in terms of operability and workability.

The present invention has been devised to effectively solve the above-mentioned conventional problems, and an object of the present invention is to provide a grip member forming a bundle portion that is substantially rigidly connected to a vibration source of a vibrating tool or the like. Vibration isolation that can almost completely block harmful vibrations despite being connected, and can be made extremely lightweight and compact.
The objective is to provide a bundle device.

The feature of the present invention is to utilize the special moment of inertia effect of the pendulum without changing the mass of the bundle or the value of the resiliency constant of the anti-vibration rubber. The present invention has the following advantages: reducing the number of vibrations, expanding the vibration insulation area, and improving the vibration insulation effect.

Prior to a detailed description of the present invention, in order to facilitate understanding of the vibration damping effect of the present invention, the vibration characteristics of the spring-equipped horizontal pendulum shown in FIG. 3 will first be described.

In Fig. 3, reference numeral 5 denotes a vibration table with a cross-sectional shape that vibrates in the vertical direction, and above the horizontal plate 5a of the vibration table 5, a lightweight and unbending rod 6 with a length l is arranged along the horizontal plate 5a. It is set up.

One end of the rod 6 is attached to the vertical plate 5b of the vibration table 5 via a hinge 7, and the other free end has a mass m.
A pendulum 8 is provided, and the pendulum 8 can rotate up and down about the hinge 7.

Also, a position a distance a from the hinge 7 of the rod 6 and the horizontal plate 5a
A spring 9 with a spring constant is vertically interposed between the two.

The natural vibration ω of the pendulum 8 of the horizontal pendulum with a spring configured in this way is expressed as follows.

Therefore, it can be seen that even if the values of m and k are constant, the natural frequency of the pendulum 8 changes depending on the value of 4, and becomes smaller as l becomes larger.

FIGS. 4I, N, and H each show the mode shapes of vibration of the pendulum 8 when the vibration table 5 is excited up and down at a frequency exceeding the natural frequency ω.

(2) is when the vibration table 5 is in the neutral position, (2) is when the vibration table 5 vibrates upward, and (2) is the case when the vibration table 5 is vibrated downward.

FIG. 4 shows that, due to the effect of the moment of inertia of the pendulum 8, the pendulum 8 has the property of remaining near the neutral position without being affected by external force (vertical vibration of the vibration table 5).

The moment of inertia of the pendulum 8 is increased by the length l.

Therefore, at frequencies exceeding the natural frequency ω, the pendulum 8 is maintained in a stationary state despite the vibration of the vibration table 5.

This means that the pendulum 8 and the rod 6 in its vicinity are isolated from the vibrations of the vibration table 5.

FIG. 5 shows a mechanical model of the vibration isolation bundle using the vibration characteristics of the horizontal pendulum.

This dynamic model is vibrationally equivalent to the anti-vibration bundle device of the present invention.

In FIG. 5, reference numeral 10 denotes a lightweight, unflexible cylindrical grip, and a shaft 11 that vibrates in the vertical direction is inserted into the base end 10a of the grip 100.

A pair of springs 1 are provided between the right end of the mandrel 11 and the grip 10 and between the left end of the mandrel 11 and the grip 10, respectively.
A Voigt element (or Voigt object) 14 is interposed in which the grip 10 and the damper 13 are connected in parallel, and the handle 10 is connected and supported by the shaft 11.

Further, a weight 15 having a mass M is attached to the tip of the grip 10.

The spring constant of each spring 12 is -8, and the viscous resistance coefficient of each dancer 13 is %.

Further, when the grip 10 of the left Voigt element 14 is attached, the distance from the position P1 to the center of gravity of the weight 15 is L, and
The distance between the attachment of the left Voigt element 14 from position P1 to the attachment of the right Voigt element 14 is e.

The natural frequency of the weight 15 in the dynamic model configured in this way is as follows.Similar to the pendulum 8 above, the natural frequency valence of the weight 15 is also equal to e/i without changing the spring constant or mass M. ,
is reduced by making it smaller.

Comparing this dynamic system with the spring-loaded horizontal pendulum shown in FIG.
5 corresponds to pendulum 8, respectively.

Furthermore, the spring 12 of the right-hand Voigt element 14 corresponds to the spring 9, and the mounting position P1 of the left-hand Voigt element 14 corresponds to the hinge 7.

Therefore, like the pendulum 8 described above, due to the moment of inertia effect of the weight 15, the weight 15 remains stationary at frequencies exceeding the natural frequency Ωn, and is insulated from the vibrations of the mandrel 11.

Next, a preferred embodiment of the present invention will be described with reference to FIG.

In FIG. 6, 16 is a connecting member, and the connecting member 16
One end 16a is threaded so that the connecting member 16 can be fixed to a vibration source (not shown) such as the casing of a hand-held electric grinder.

The other end 16b of the connecting member 16 is formed into a rod shape, and a cylindrical viscoelastic member 17 made of anti-vibration rubber or the like is provided so as to cover the outer circumferential side of the rod.

Further, on the outside of the viscoelastic member 17, there is provided a base end portion 18 thereof.
A lightweight tubular grip member 18 is provided by fitting the parts a into each other.

The outer circumferential surface of the other end 16b of the connecting member 16 and the inner circumferential surface of the viscoelastic member 17 and the outer circumferential surface of the viscoelastic member 17 and the inner circumferential surface of the grip member 18 are adhesively fixed by rubber vulcanization or the like, and the grip member 18 is made of a viscoelastic member. It is connected and supported by the connecting member 16 via 17.

Since the length of the viscoelastic member 17 in the axial direction of the grip member 18 is sufficiently long, the grip member 18 is firmly connected to the connection member 16.

A mass body 19 is attached to the tip end 18b of the grip member 18 by being partially fitted therein and fixed by welding or the like.

Further, a flange-shaped collar portion 20 is provided at the base end of the grip member 180.
is formed.

Comparing this embodiment configured in this way with the dynamic model shown in FIG.
5, and the viscoelastic member 1T of this example.
Since this is a continuum of a spring and a damper connected in parallel, it can be represented by a pair of Voigt elements 14 provided in parallel between the mandrel 11 and the grip 10.

Therefore, similar to the mechanical model shown in FIG. 5 above, due to the large moment of inertia of the mass body 19, the mass body 19 and the grip member 18 in its vicinity tend to maintain a stationary state despite the vibration of the connecting member 16. Therefore, harmful vibrations from the vibration source to the mass body 19 and the grip member 18 in its vicinity are almost completely blocked.

Further, since the moment of inertia effect of the mass body 19 is utilized, the mass of the mass body 19 is sufficient, and the handle device of the present invention can be made extremely lightweight and compact.

Note that in the above embodiment, the other end 1 of the connecting member 16
Although 6b is formed into a rod shape, it may be formed into, for example, a cup shape, into which the proximal end of the grip member is inserted, and the two may be connected by a viscoelastic body.

Further, in the above embodiment, the viscoelastic member 17 is integrally formed, but as shown in FIG.
17b may be formed separately into a distal end portion and a proximal end portion of the other end portion 16b of the connecting member 16.

The base end side of the viscoelastic member 17b is formed with an enlarged diameter so that the flange 21 at the base end of the grip member 18 and the vibration receiver of the connecting member 16 are held between the body 16c.

This embodiment can improve the durability of the viscoelastic member compared to the above embodiments.

FIGS. 7A and 7B show the vibration accelerations transmitted to a conventional standard handle and the handle device of the above-described embodiment of the present invention when attached to a commercially available hand-held electric grinder.

In FIG. 7, the horizontal axis is time, the vertical axis is acceleration, and g is gravitational acceleration.

As shown in FIG. 7, it can be seen that in the handle device of the present invention, the vibration acceleration amplitude transmitted from the hand-held electric grinder is significantly reduced to about 100% compared to the conventional handle.

As is clear from the above description, according to the present invention, even though the grip member serving as the handle portion is substantially rigidly connected to the vibration source, harmful vibrations from the vibration source can be almost completely blocked. Moreover, it can exhibit excellent effects such as being lightweight and small in size.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a mechanical model of a conventional anti-vibration handle, Fig. 2 is a graph showing the frequency characteristics of the same handle, Fig. 3 is a side sectional view showing a horizontal pendulum with a spring, and Fig. 4 is I, n, II
I is a side sectional view showing the mode shapes of vibration of the horizontal pendulum, FIG. 5 is a diagram showing a mechanical model equivalent to the present invention, and FIG.
FIG. 7A is a longitudinal sectional view showing an embodiment of the handle device according to the present invention. B is a graph showing the vibration acceleration transmitted when a conventional hand-held electric grinder and the handle device of the present invention are attached to a commercially available hand-held electric grinder, and FIG. 8 is a longitudinal cross-sectional view showing another embodiment of the present invention. It is. In the figure, 16 is a connecting member, 17 is a viscoelastic member, 18 is a grip member, and 19 is a mass body.

Claims (1)

[Claims] 1. A connecting member connected to a vibration source and extending therefrom, a viscoelastic member attached to the connecting member, and a tubular grip member having its base end attached to the viscoelastic member; A vibration-proof nodle device comprising: a mass body provided at the tip of the grip member.