JPH0255588B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for mounting a vibrating motor for compacting concrete for construction and civil engineering.

[Conventional technology]

At construction sites with concrete structures, in order to ensure that the poured concrete reaches every nook and cranny, it is necessary to
A vibrating electric motor with a rotation speed of 60 Hz is strongly fixed to a pipe reinforced by the formwork, and vibrates the concrete through this reinforcing material.

FIG. 3 is a partially cutaway side view showing the configuration of a general vibration electric motor, in which 41 is a stator, 42 is a rotor, 43 is a winding coil, 44 is a shaft, 45 is a bearing, 46 is an unbalanced weight, 47 is a frame, and 48 is a bracket. When this vibration motor is energized, current flows through the winding coil 43 and the rotor 42 rotates. Since the shaft 44 is press-fitted into the rotor 42, it rotates together with the rotor 42.

Both ends of the shaft 44 are supported by bearings 45, allowing smooth rotation. An unbalanced weight 46 is fixed inside the bearing 45 and rotates together with the shaft 44.

Here, if the weight of the unbalanced weight that is the result of the two unbalanced weights 46 is W [Kgf], and the distance from the center of the shaft 44 to the center of gravity of the unbalanced weight is r, then the angular velocity ω [ The centrifugal force F when rotating at radian/sec is F=Wrω ² /g [Kgf] (where g is gravitational acceleration = 980 cm/sec ² ). This is the vibration force generation principle of general vibration motors, and is the fourth principle.
As shown in the figure, centrifugal force F is generated on a line connecting the center of the shaft and the center of gravity of the unbalanced weight.

5 and 6 (respectively, a is a plan view, b is a side view, and c is a front view), the vibration electric motor 1 is fixed to the reinforcing pipe 11 with a clamp fitting 22,
23 with a screw 24 and a lever handle 25.

In Figure 5a, F ₁ is an effective force that vibrates the pipe, but F ₂ is an ineffective force, and furthermore,
Low resonant frequency in this direction (3000~4500rpm)
This causes the inconvenience that the engine resonates and consumes a large amount of input, the rotation does not increase, the specified rotation speed is not achieved, and the vibration force is small.

This resonance in the _y2 direction is caused by the deformation in the y direction of the reinforcing pipe 12, which is reinforced by being inserted at right angles to the reinforcing pipe 11.

On the other hand, as shown in FIG. 6b, when _F1 acts on the line connecting the center of the reinforcing pipe 11 and the center of the vibration motor 1, the vibrating motor shown in FIG. 6 moves in this direction without rotational motion. Force is transmitted, but if the force is in a phase other than this, a force that twists the reinforcing pipe 11 acts, and is maximum at _F2 , which is perpendicular to _F1 .

The torsional resonance point of the reinforcing pipe 11 is also between a relatively low rotational speed (3000 to 4500 rpm), and resonance occurs at this point, causing large vibration in the _F2 direction. In this case, _F2 is consumed to accelerate the mass of the vibrating body around the center of the reinforcing pipe 11, and the remaining amount gives vibration to the reinforcing pipe 11, so the effect is small.

[Problem that the invention seeks to solve]

In this way, with the conventional mounting method of a vibrating electric motor, there are many resonance frequencies below 6000 rpm due to the structure, so if one of them resonates, the vibrating electric motor will not be able to increase the rotation speed any further (for example, 3500 rpm).
), the vibration force is weak, and due to the characteristics of the electric motor,
Intermediate speeds required more current and input.

The present invention aims to solve these conventional problems.

[Means for solving problems]

The present invention fixes the vibrating motor to the excitation surface with a fixing plate made of a leaf spring perpendicular to the excitation surface, with the rotating shaft positioned in a plane substantially parallel to the excitation surface, and Mounting of the vibrating motor, characterized in that a steady rest means is provided between the casing of the vibrating motor and the vibrating surface for suppressing vibrations parallel to the vibrating surface of the vibrating motor casing within a predetermined width. It's a method.

[Effect]

By adopting this installation method, the
It can easily pass through a resonance frequency lower than the resonance frequency of 4500rpm and rotate at the set rotation speed of 6000rpm.
It can produce the necessary rotation speed and vibration frequency.

〔Example〕

Hereinafter, the present invention will be specifically explained based on Examples.

FIG. 1 shows an embodiment according to the present invention, in which a is a plan view, b is a side view, and c is a front view. In the figure, 1 is a vibration electric motor, 2 is a clamp fitting, 3 is a fixed handle, 4 is a fixed plate made of leaf spring material, 5 is a lever that is screwed into the threaded part of the fixed handle 3 and rotates, 6 7 is a protrusion provided on the casing of the vibrating motor 1, and 8 is a cushion rubber provided on both sides of the protrusion.

Further, 11 and 12 are reinforcing pipes, 13 and 14 are concrete formworks, 15 are spacer bolts for both the formworks 13 and 14, and 16 are nuts for fixing the reinforcing pipe 11 to the spacer bolts 15.

As shown in Fig. 1, by connecting the vibrating motor 1 and the clamp fitting 2 with a fixed plate 4 made of a plate spring material, a large force is transmitted only in the _y direction, and a small force is transmitted in the direction perpendicular to this. Since it only transmits force,
It is not affected by the resonance frequency in the _y direction. Alternatively, the same effect can be obtained even if the vibration motor 1 and the fixed plate 4 are left as they are and attached to the clamp fitting 2 by rotating them by 90 degrees.

In Figure 1a, the weight of the vibrating motor 1 is W ₀
[Kgf], and the spring constant of the fixed plate 4 is K [Kg/cm]
Then, the vibration force becomes F=Wrω ² /g, and the amplitude width a [cm] at this time is a=F(K−W ₀ ω ² /g) = (Wr ₁ ω ² /g)/(K −W ₀ ω ² /g)
......Equation (1) is obtained. At this time, the resonant frequency f ₀ =2πω ₀ is K−
It is obtained as W ₀ ω ² /g=0. From this, f ₀ =
(1/2π)√ ₀ Now, if W ₀ = 3.5Kg, K = 70Kg/cm, then f ₀
= 22.28 Hz, n ₀ = 60f ₀ = 1336 rpm, which is considerably different from the resonant frequency of the structure of 3000 to 4500 rpm.

Therefore, when the power is turned on and the vibrating motor starts rotating, the vibrating motor vibrates greatly in the _y2 direction as n=1336 rpm approaches. Then, the protrusion 7 shown in FIG. 1 that was vibrating in the gap between it and the cushion rubber 8 begins to come into contact with the cushion rubber 8. The spring constant of cushion rubber 8 is high, for example 2000Kg/cm, so it does not amplify the amplitude (if 70Kg/cm
If it is close to cm, it will be amplified). During this time, the rotational speed of the vibration motor increases and becomes unrelated to this resonant frequency.

F=Wrω ² /g, for example, F=150Kg, n=
If 6000 rpm and ω=2π×100, then Wr≒0.37Kgcm, and by substituting the above value into equation (1), we get a=0.37ω ² ×10mm/(68600−3.5ω ² ).
Figure 2 shows the amplitude a versus rotation speed based on this formula.
It is a graph showing a change in (half amplitude). In this graph, when there is no limit on the amplitude, the amplitude increases as the rotation speed increases from a → b → ∞ → c → d → e
However, in the present invention, the damper action is performed by the cushion rubbers 8, 8, so when the amplitude is set to 2 mm, the amplitude is limited at point a, and the actual value is 0.
→The curve will be traced from a → d → e.

This is because, as shown in Figure 1a, a force in the y ₂ direction acts on the fixing metal fitting 2 due to the amplitude in the y ₂ direction, but this is very small compared to the vibration force, so the vibration is large at the resonance point in this direction. The rotational speed easily passes through this point and increases to the specified rotational speed, producing the specified vibration force.

For example, assuming that there is a resonance point at 4000 rpm, the amplitude at that time is a = 1.1 mm = 0.11 cm. Since the spring constant of the fixing plates 4, 4 is K=70Kg/cm, the force acting on the fixing metal fitting 2 in the _y2 direction is Q=Ka, so Q=70Kg/cm×0.11cm=7.7Kg. The vibration force generated at this time = Wrω ² /g = 66Kg, and Q is 1/8.5 of the vibration force at this time. The force in y _direction is 66
Kg.

In this way, by using the fixed plate 4, the force in the _y2 direction can be reduced and the resonance point in this direction can be easily passed through. Furthermore, a small value of Q means that the force for tightening the fixture 2 can be reduced, and it has the advantage of being easy to install and remove, and also lightweight.

Compared to the case in Figure 5, vibration force F = 150Kg
In order to prevent slippage in the y _direction , the clamping force of the reinforcing pipes 11 and 12 must be 150/μ=150/0.15=1000Kg or more. However, μ is the friction coefficient.

In the case of FIG. 6, in order to prevent the pipe from slipping due to the pipe clamping force, a force similar to or greater than the above is required.

In the case of the present invention, a clamping force slightly larger than 150 kg in the _y direction, for example, 200 kg, is sufficient, so a clamping force of about 1/5 of that of the conventional one is sufficient.

Further, although the fixing metal fittings having the structure shown in FIG. 5 are simple, if the screws 25 are loosened, the vibration motor 1 may fall.

In the present invention, even if the screw 3 becomes loose and loses its tightening force, the lever 5 is caught and will not fall. This is important for risk prevention.

〔Effect of the invention〕

As described above, according to the present invention, conventionally it rotated at an intermediate resonant frequency and could not produce the desired rotational speed and vibration force, but with the present invention, it is possible to produce the desired rotational speed and vibration force. The mounting force is reduced to about 1/5 compared to conventional ones, and there is no need for spanners or levers, just a handle the size of a water tap, and the weight is significantly reduced. This has the effect of making work much easier and compacting concrete more efficiently.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a graph comparing the effects of the present invention and a conventional method, and Fig. 3 is a graph showing an example of the present invention.
The figure is a partially cutaway side view showing the configuration of a general vibration electric motor, Figure 4 is an explanatory diagram showing the generation of centrifugal force, and Figure 5
FIG. 6 and FIG. 6 are diagrams each showing a conventional mounting method. 1: Vibration electric motor, 2: Clamp fitting, 3: Fixed handle, 4: Fixed plate, 5: Lever, 6: Holding plate, 7: Projection, 8: Cushion rubber, 11,1
2: Reinforcement pipe, 13, 14: Concrete formwork, 15: Spacer bolt, 16: Nut.

Claims (1)

[Claims] 1. The vibration motor is fixed to the vibration surface by a fixing plate made of a leaf spring material perpendicular to the vibration surface, with the rotating shaft located in a plane substantially parallel to the vibration surface, and the vibration motor is A method for mounting a vibrating motor, characterized in that a vibration stop means is provided between the casing and the vibrating surface for suppressing vibrations parallel to the vibrating surface of the vibrating motor casing within a predetermined width.