JP2664989B2 - Variable eccentricity vibrator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibrator used for driving a pile or compacting a ground, and includes a vibration roller, a vibration tester, a vibration feeder, and a vibration conveyor. And the like.

[Conventional technology]

A conventional vibrator has a constant eccentricity (FIG. 6), a pin provided on an eccentric weight, and the amount of eccentricity is changed by attaching and detaching the pin (FIG. 7). The eccentric weight is a fixed weight and a floating weight. The eccentric amount is changed by changing the bolt mounting position of the floating weight with respect to the fixed weight and changing the relative angle (FIG. 8). The eccentric weight is composed of the fixed weight and the floating weight. The lower stage has two stages by a stopper, and the setting is performed with the rotational force according to the forward / reverse rotation axis, and the amount of eccentricity is changed to two stages (FIG. 9). There is one that changes the amount of eccentricity by changing the mounting angle of the lower eccentric weight (Fig. 10).

6 to 10, 1 is a vibrator body,
5 is a belt, 6 is a pulley, 7 is a synchronous gear, 8 is a fixed weight, 9 is a floating weight, 10 is a key, 15 is a motor, 18 is a variable eccentric pin, 19 is a mounting bolt, 20 is a stopper, and 21 is a rotating shaft. It is.

In the apparatus shown in FIG. 6, since the eccentric weight is constituted only by the fixed weight 8, even when the vibrator starts or stops, the vibrator necessarily vibrates, and the resonance point of the shock absorber spring Resonance occurs when passing through.

In the device of FIG. 7, the amount of eccentricity can be changed by attaching / detaching the variable eccentric pin 18, but the amount of eccentricity cannot be changed during rotation. Cause resonance.

8 also disassembles the machine to change the amount of eccentricity,
It is necessary to change the position of the floating weight 9 with the mounting bolt 19, and resonance cannot be avoided when passing through the resonance point of the shock absorber spring.

In the apparatus shown in FIG. 9, the amount of eccentricity is changed by reversing the rotation directions of the rotation axis (A) 2 and the rotation axis (B) 3 so as to determine the relative angle of the floating weight 9 to the stopper 20. Is changed, so that a two-stage change is possible. However, in order to change the amount of eccentricity, it is necessary to stop the machine, and it is not possible to avoid resonance at the time of starting and stopping.

In the apparatus shown in FIG. 10, the eccentric weights are constituted only by the fixed weights 8, and the rotating shafts 21 are provided two each in the upper and lower stages.
They are connected to each other by a synchronous gear 7. The amount of eccentricity is changed by changing the meshing position of the upper and lower synchronous gears 7.

In this apparatus, similarly to the apparatus shown in FIG. 9, it is necessary to stop the machine in order to change the amount of eccentricity, and resonance at the time of starting and stopping cannot be avoided.

[Problems to be solved by the invention]

(1) As a matter of course, in the device having a constant eccentricity shown in FIG.
In order to change the amount of eccentricity in FIGS. 7 and 8 as well, it is necessary to stop and disassemble the machine, and to attach and detach the pins of the eccentric weights inside, and to stop the operation during operation. It is not possible to change the eccentricity while maintaining the constant eccentricity up to this point.

(2) In the apparatus shown in FIGS. 9 to 10, the amount of eccentricity can be changed from the outside without disassembling the machine, but the machine needs to be stopped once. During this period, the amount of eccentricity cannot be changed.

However, when the vibrator is suspended with a suspension type or integrated type shock absorber, the resonance frequency of the shock absorber is lower than the steady frequency in order to have a damping effect. Since the vibrations pass through the resonance point between them, the vibrator vibrates with a large amplitude, and the adverse effects due to the strength and propagation vibration of the shock absorber and peripheral devices become a serious problem.

According to the present invention, the eccentricity is maintained at 0 during the period from when the rotation of the vibrator stops until the rotation reaches the specified rotation speed, and the eccentricity is changed to a predetermined amount during the rotation from the specified rotation speed to the steady rotation speed. It is an object of the present invention to provide a variable eccentric amount vibrator capable of eliminating an adverse effect due to resonance by setting the resonance frequency of the shock absorber to be within a specified rotation speed at which the vibration starts to change from 0. It is.

[Means for solving the problem]

Consists of a fixed weight with the eccentric weight fixed to the rotating shaft and a floating weight that is freely rotatable around the mounting shaft center eccentric to the center of the rotating shaft. Eccentric rotation due to centrifugal force generated in the floating weight by rotation of the rotating shaft The floating weight is rotated according to the force, utilizing the balance between the rotating force and the spring force provided between the fixed weight and the floating weight, the specified rotation speed is selected higher than the shock absorber spring and the resonance frequency, The spring force prevails up to the specified number of rotations, and the stop weight is defined by the stopper so that the relative eccentric angle between the floating weight and the fixed weight, where the amount of eccentricity = 0, is maintained at 180 °.

Next, from the specified rotation speed to the steady rotation speed, the eccentric rotation force of the floating weight exceeds the spring force due to the increase of the rotation speed and the eccentric relative angle is automatically reduced to 180 ° → minimum, and the floating weight and the fixed weight are The eccentric relative angle = minimum and the amount of eccentricity = maximum are defined by a stopper so that a predetermined vibrating force can be obtained in a steady rotation class.

(Operation)

When the rotation speed of the rotating shaft is gradually increased from 0, the center of rotation of the floating weight is eccentric with respect to the center of the rotating shaft, so the floating weight rotates around the eccentric center axis due to the centrifugal force of the floating weight generated by the rotation. The relative angle with the fixed weight can be changed by adjusting the rotation speed of the rotating shaft.

Now, when the number of rotations of the rotating shaft is from 0 to the specified number of rotations, the spring force provided between the fixed weight and the floating weight and the eccentric rotation force generated in the floating weight are always balanced by the spring force. The eccentric relative angle between the fixed weight and the floating weight is opposite by 180 °, and the eccentricity is held at a specified position by a stopper so that the eccentricity is maintained at 0. When the rotation speed exceeds the specified rotation speed, the eccentric rotation force increases the spring force. As the rotation speed increases, the eccentricity relative angle changes from 180 ° to a minimum → When the rotation speed reaches the steady rotation speed, the eccentricity relative angle is kept at the minimum value. A predetermined vibrating force is obtained.

Therefore, if the specified rotation speed is set to be higher than the resonance rotation speed of the shock absorber, even when the vibrator passes the resonance rotation speed of the shock absorber at the time of starting and stopping, it vibrates with the eccentricity of the vibration machine = 0. And the resonance phenomenon such as an increase in the amplitude of the vibrator can be completely prevented.

〔Example〕

An embodiment of the present invention in a one-stage two-shaft vibrator constituted by two sets of right and left eccentric amount variable weights will be described with reference to FIGS. 1 to 5. FIG.

A rotating shaft (A) 2 and a rotating shaft (B) 3, both ends of which are supported by bearings 4, are disposed on the left and right inside the exciter body 1, and a synchronous gear 7 is assembled to each of them so as to mesh with each other.

A pulley 6 is attached to one end of the rotating shaft (A) 2, and a belt 5 is attached thereto.

A key 10 is provided at the center of the rotation axis (A) 2 and the rotation axis (B) 3.
The fixed weight 8 is attached by using the above. A cylindrical portion 16 eccentric with respect to the center of the rotating shaft is provided on the rotating shaft mounting portion of the fixed weight 8.

A floating weight 9 is attached to the cylindrical convex portion 16, and a spring 11 is mounted on a cavity 17 on the contact surface side with the fixed weight 8 by using a mounting pin 12, one end of which is on the fixed weight 8 side and the other end is of the floating weight 9. It is assembled by giving the initial force to.

The fixed weight 8 is provided with an upper limit stopper 13 and a lower limit stopper 14 in order to define the upper and lower limit positions of the rotational movement angle of the floating weight 9.

Further, a pulley 6 provided at an end of the rotating shaft (A) 2 and the other end of the belt 5 wound around the pulley 6 are connected to a motor 15 mounted on an upper portion of the exciter body 1.

Now, when the motor 15 is rotated, the pulley 6 and the rotary shaft (A) 2 rotate via the belt 5, and at the same time, the rotary shaft (B) 3 rotates in the opposite direction by the action of the synchronous gear 7.

Then, the fixed weight 8 and the floating weight 9 attached to the rotating shaft (A) 2 and the rotating shaft (B) 3 rotate synchronously in opposite directions to each other, so that the relative mounting angles of the left and right fixed weights 8 and the floating weight 9 are the same. , The left and right components (horizontal direction) of the combined centrifugal force generated by the fixed weight 8 and the floating weight 9 are canceled out, and only the vertical component remains. It becomes a vibrator that generates vibration.

Next, a change in the amount of eccentricity accompanying a change in the number of revolutions will be described.

In FIG. 2, the rotation axis (A) 2 or the rotation axis (B) 3
A cylindrical portion 16 is formed on one side of the shaft mounting portion of the fixed weight 8 which is fixed to the center of the rotating shaft so as to be eccentric so that the shaft center is different from the center of the rotating shaft, and the floating weight 9 is rotatably mounted on the eccentric cylindrical portion 16. .

A groove 17 is provided at the center of both sides of the contact between the fixed weight 8 and the floating weight 9, and a spring 11 is provided therein. It is attached by giving a great initial force.

Further, in order to define the rotation angle range of the floating weight 9, an upper limit stopper 13 is provided at a position where the relative angle between the fixed weight 8 and the floating weight 9 is minimum, and a lower limit stopper 14 is provided at a position 180 ° opposite.

Figure 3 is an illustration that rotational force T for rotating the floating weight 9 about the eccentric shaft by the action of centrifugal force f idler weight 9 generated by the rotation of the rotating shaft is generated around the center 0 _1, This rotational force T is expressed by the following equation.

T = fr ₂ sin (θ ₀ + θ) = mr ₁ ω ² r ₂ sin (θ ₀ + θ) With this rotational force T, the relative angle between the fixed weight 8 and the floating weight 9 automatically changes.

FIG. 4 shows the relative angular position of the fixed weight 8 and the floating weight 9 from the stopped state where the rotation speed of the rotary shaft is low to the specified rotation speed. In this case, the centrifugal force generated in the floating weight 9 is small. Fixed weight 8 because torque T is small
And the initial force of the spring 11 connected between the floating weights 9 wins, and the relative angle is maintained at the position defined by the lower limit stopper 14 where the relative angle is opposite by 180 °.

In addition, the specified rotation speed is a rotation speed higher than the resonance rotation speed of the shock absorber spring because it is necessary to avoid resonance with the shock absorber spring. At the resonance rotation speed, the eccentric amount is kept at 0 and the vibrator does not vibrate. Needless to say, do so.

FIG. 5 shows a state in which the rotational speed of the rotating shaft has changed from the prescribed rotational speed to the steady rotational speed, contrary to FIG. 4, and the rotational force T acting on the floating weight 9 becomes larger than the force of the spring 11 and the floating The weight starts rotating and rotates to the position defined by the upper limit stopper 13 at which the relative angle between the fixed weight 8 and the floating weight 9 becomes minimum, and the weight is held in the state of maximum eccentricity.

As a result, the vibrator generates a predetermined vibrating force at a steady rotational speed and vibrates.

〔The invention's effect〕

According to the present invention, as described above, a fixed weight fixed to a rotating shaft in a vibrator that generates eccentric weights by attaching eccentric weights to two rotating shafts that are supported in parallel and rotate in opposite directions, A floating weight eccentrically mounted on the shaft and rotatably mounted, a spring interposed between the fixed weight and the floating weight to change the relative angle between the two weights, and an upper limit and a lower limit of the rotation angle of the floating weight with respect to the fixed weight. The stopper has a regulating stopper.At the time of low speed rotation, the combined eccentricity of the fixed weight and the floating weight is held at the lower limit by the force of the spring, and at the time of high speed rotation, the floating weight rotates relative to the fixed weight, and Since the combined eccentricity increases and is maintained at the upper limit, the rotation shaft is rotated to reduce the rotation speed. When the rotation speed is changed from 0 to low speed, the centrifugal force generated in the floating weight on the eccentric shaft causes the eccentric rotational moment to be smaller than the initial setting force of the spring, so the floating weight is held at the lower limit stopper position. However, between low speed and high speed, the eccentric rotational moment becomes larger than the initial set force of the spring due to the increase in centrifugal force, and the idle weight is rotated and held to the upper limit stopper position. With high performance, the resonance phenomenon with the shock absorber spring that occurs when the vibrator starts and stops completely disappears, so the damper, base machine and peripheral equipment are damaged by the large amplitude at the time of resonance, and the operating environment of the operator deteriorates. This has the effect of preventing generation of noise and the like.

[Brief description of the drawings]

1 (a) and 1 (b) are plan and side sectional views of an eccentric amount variable vibrator according to an embodiment of the present invention, FIG. 2 is a perspective view of a fixed weight and a floating weight portion, and FIG. FIG. 4 is a state diagram of a weight set at a lower limit stopper position at low speed, FIG. 5 is a state diagram of a weight set at an upper limit stop position at high speed, and FIG.
FIG. 7 is a side cross-sectional view of a conventional device with a constant eccentric amount, FIG. 7 is a side cross-sectional view of a conventional device with a variable eccentric amount weight with a detachable pin,
FIG. 8 is a side sectional view of a relative angle reconfigurable variable eccentricity variable weight type conventional device comprising a fixed weight and a floating weight, and FIG.
The figure consists of a fixed weight and a floating weight, and the change in the amount of eccentricity is a side sectional view of a two-stage variable weight type conventional device in which the change in the amount of eccentricity is defined by the stop position corresponding to the forward / reverse rotation of the rotating shaft. FIG. It is a side view of the conventional device of the system of changing the amount of eccentricity by changing the meshing position of the rotating shaft. 2 ... rotating shaft (A), 3 ... rotating shaft (B) 8 ... fixed weight, 9 ... floating weight 11 ... spring, 13 ... upper limit stopper 14 ... lower limit stopper, 16 ... eccentric cylindrical part

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Hideo Shiroura 285-1 Ozakicho, Hannan-cho, Sennan-gun, Osaka 7-402, Izumi-Minami-Ozaki housing complex

Claims (1)

(57) [Claims] An eccentric weight is attached to two rotating shafts supported in parallel and rotating in opposite directions to generate vibration in a fixed direction. A fixed weight fixed to the rotating shaft and a fixed weight fixed to the rotating shaft are provided. A floating weight eccentrically mounted rotatably, a spring interposed between the fixed weight and the floating weight to change the relative angle between the two weights, and the upper and lower limits of the rotation angle of the floating weight with respect to the fixed weight are regulated. When the motor rotates at a low speed, the combined eccentricity of the fixed weight and the floating weight is held at a lower limit by the force of the spring, and at a high speed rotation, the floating weight rotates with respect to the fixed weight. An eccentric amount variable vibrator characterized in that the combined eccentric amount increases and is maintained at an upper limit.