JP2926097B2 - Hydraulic vibrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention generally relates to a vibrator that generates mechanical vibration, and is particularly based on vibration of a vibration tester, a vibration transport device, a rock drill, and the like. It is related to the device that performs. More particularly, the present invention relates to a vibrator using a fluid pressure such as a hydraulic pressure. (Prior Art) Various proposals have been made for a vibration testing device, a vibration transport device, a rock drill, etc., regarding a vibration device and a method using a hydraulic type, a mechanical type, and an unbalanced weight. less than,
Some of the technologies that have already been put into practical use will be described. The first is an apparatus and method using hydraulic pressure. this is,
As shown in the circuit diagram of FIG. 2, first, a hydraulic pump 2 is directly connected to an electric motor 1 having a constant rotational speed to form a hydraulic supply device.
Next, the hydraulic cylinder 4 is operated by a valve 3, such as a servo valve or a proportional control valve, which can control the flow rate and direction of the fluid. A sensor 5 capable of detecting parameters such as displacement, speed, and acceleration is attached to the ram of the hydraulic cylinder 4. Further, the output signal of the function generator 6 and the signal of the sensor 5 are added to an adder 7, and the added signal is amplified by a servo amplifier 8 to control the above-described servo valves and the like, so that the same displacement as the signal waveform of the fraction generator is obtained. ·speed·
A ram operation such as acceleration is performed. The second is a method and apparatus using unbalanced weights. This is because, as shown in FIG. 3, if a wheel with an unbalanced weight, such as a driving wheel of a steam locomotive, is simply rotated, the vibration locus also draws a circle. Therefore, in order to vibrate in only one direction, a device as shown in FIG. 4 is required. That is, by attaching an unbalanced weight to the two wheels 9a and 9b and rotating them in synchronization in opposite directions, vertical vibration can be obtained. (Problems to be Solved by the Invention) The first is that a large power can be obtained, and the vibration frequency covers a wide range of DC to 500 Hz. However, in order to vibrate with a sine waveform that does not include harmonics or to obtain a wide range of vibration frequencies, a servo valve must be used, resulting in a very expensive device. The second type is practically used as a low-cost device. However, this means that one rotation of the wheel is 1 Hz of vibration, and the vibration frequency is determined by the rotation speed range of the wheel. In addition, if this rotational speed can be varied by a continuously variable transmission, the limit is at most about 6 to 60 Hz (1:10).
Further, the vibration waveform is limited to a sine wave by swinging the unbalanced weight. Then, the vibration of the driving coupling, belt, bearing and the like is also superimposed, and the obtained vibration waveform does not become a clean sine wave but becomes a waveform containing many harmonics. Therefore, it would be best if a device with as low a cost as possible and with an accurate vibration waveform and a wide vibration frequency range comparable to the hydraulic servo system could be made. However, when examining the vibration waveform in detail, it was found that the rise and fall of a square wave due to the weight (inertia) of the vibration table and the DUT
There is no point in applying a sudden acceleration when falling. Therefore, it can be understood that a sine wave, a triangular wave, a trapezoidal wave, or the like can be obtained for this vibration waveform. Also, the vibration test according to the JIS standard is in the range of 2 to 100 Hz for ordinary equipment. (Means for solving the problem) Taking the above conditions into consideration, three types of sine wave, triangular wave, and trapezoidal wave can be selected, and the frequency range is about 2 to 100 Hz. In order to bring the device to the market, a hydraulic drive system is most advantageous. However, a device using a servo valve has extremely low energy efficiency, and it is difficult to reduce the manufacturing cost. A fluid pressure vibrator according to the present invention is a combination of a variable displacement fluid pressure supply device, an AC fluid pressure pump, and a liquid reciprocating actuator in order to solve the above-mentioned problem. Hereinafter, a specific configuration of the fluid pressure vibrator according to the present invention will be described. First, as shown in FIG. 1, there is a variable displacement hydraulic pressure supply device comprising an electric motor and a variable displacement hydraulic pump.
Next, there is a hydraulic motor and an AC hydraulic pump directly connected thereto. Both ports of the AC fluid pressure pump, a throttle valve, and a hydraulic reciprocating actuator are connected in parallel by piping. That is, the fluid pressure vibrator described in claim 1 includes a prime mover such as an internal combustion engine or an electric motor capable of controlling a rotation speed, an AC fluid pressure pump, a throttle valve capable of varying a throttle amount, and a hydraulic reciprocating actuator. In the hydraulic drive vibration device provided, the AC fluid pressure pump is driven by the prime mover so that the rotation speed is variable, the AC pressure oil proportional to the rotation speed is output, and the hydraulic reciprocating actuator is driven by the pressure oil. The vibrating table is vibrated at the same frequency as the AC pressure oil, the amount of throttle of the throttle valve is varied, and the amplitude is controlled. The hydraulic vibrator described in claim 2 includes a prime mover such as an internal combustion engine or an electric motor capable of controlling the rotation speed, a one-way discharge variable displacement hydraulic pump, a hydraulic motor, an AC hydraulic pump, and a throttle amount. In a hydraulic drive and vibration device having a variable throttle valve and a reciprocating actuator, a one-way discharge variable displacement hydraulic pump is driven by a motor at a variable rotational speed, and the displacement of the pump is further varied. The capacity ratio of the pump is greatly expanded without extremely impairing the linearity, and the AC fluid pressure pump is driven at a speed proportional to the amount of the discharged DC pressure oil, and the AC pressure is proportional to the rotation speed of the pump. The oil is output and the hydraulic oil drives the hydraulic reciprocating actuator to vibrate the shaking table at the same frequency as the AC hydraulic oil, and also changes the throttle amount of the throttle valve to control its amplitude. Than it is. Finally, in the fluid pressure vibrator described in claim 3, the alternating-current fluid pump described in claims 1 and 2 discharges alternating-current pressure oil in one-way rotation, and has a major axis and a minor axis. Having a circular outer stator, a circular outer stator, and an even number of cylinder chambers and a piston fitted to the cylinder chambers in the stator, and discharging two or four cycles of AC pressure oil per rotation. It is. (Operation) The hydraulic vibrator of the present invention has the following operation because of the above-described configuration. The operation will be described below. First, the hydraulic motor is driven to rotate in one direction by DC pressure oil supplied from the variable capacity hydraulic pressure supply device. The rotation speed of the hydraulic motor is proportional to the flow rate of the DC pressure oil. The AC fluid pressure pump directly connected to the hydraulic motor rotates in one direction and outputs two cycles of AC pressure oil per rotation. A hydraulic cylinder (hydraulic reciprocating actuator) reciprocates with the alternating pressure oil, and its amplitude becomes maximum when the throttle valve is open and minimum when the throttle valve is closed. Therefore, hydraulic cylinder (hydraulic reciprocating actuator)
Is proportional to the rotation speed of the AC fluid pressure pump, and its amplitude is determined by the opening of the throttle valve. (Embodiment) FIG. 1 shows a circuit and configuration of an embodiment of a fluid pressure vibrator of the present invention. First, the inverter
There is a hydraulic motor 14 that is rotated in one direction by DC pressure oil supplied from a variable capacity hydraulic pressure supply device including a motor 11 and a motor 12 and a variable capacity hydraulic pump 13. The AC hydraulic pump 20 mechanically connected directly to the hydraulic motor 14 is rotated in one direction by the hydraulic motor, and its rotation speed is proportional to the amount of DC hydraulic oil output from the variable capacity hydraulic supply device. I do. The AC fluid pressure pump 20 that rotates in one direction discharges two cycles of AC pressure oil per one rotation. The hydraulic reciprocating actuator 30 reciprocates by the alternating pressure oil. The reciprocating frequency is twice as high as the rotation speed of the AC fluid pressure pump. The amplitude of the hydraulic cylinder (hydraulic reciprocating actuator 30) is determined by the opening of throttle valve 40. Usually, the rotation ratio at which the electric motor can stably rotate at a predetermined output is about 1:10. In addition, the variable displacement liquid pressure pump also has a discharge capacity ratio of about 1:10 that can maintain the linearity of the output oil amount at the rated rotation. Therefore, if the rotational speed of the electric motor is controlled to about 1:10 by the inverter and the discharge amount of the variable capacity liquid pump is further controlled to about 1:10, the discharge ratio of the pressure oil becomes about 1: 100 as in the following equation. It becomes possible. Q ratio = rotation ratio of electric motor × discharge capacity ratio of hydraulic pump Q ratio: discharge capacity ratio of variable hydraulic pressure supply device As shown in FIG. Can be output. This can be considered as a modification of the horizontally opposed two-cylinder pump shown in FIG. However, in this method, the crankshaft makes one rotation and the operation oil flows in and out in one cycle.
The rotation speed of motors and hydraulic motors is usually 3,000 to
3,600 RPM. In order to discharge 100 hertz of AC pressure oil with a hydraulic pump that discharges one cycle of AC pressure oil in one revolution, it is necessary to rotate at 6,000 PRM, which causes problems in running noise, vibration or life. is there. The AC hydraulic pump 20 shown in FIG. 5 can be used together with the electric motor 12, the variable displacement hydraulic pump 13, and the hydraulic motor 14 in a generally used rotation range, which is convenient. Reciprocating vibration can be generated in the double rod type cylinder by the obtained alternating pressure oil, or reciprocating motion can be performed by a mechanism that converts the oscillating rotation of the oscillating rotary hydraulic motor into reciprocating motion. Therefore, the reciprocating motion generating mechanism is hereinafter referred to as a hydraulic reciprocating actuator 30. In this state, the amplitude or the swing rotation angle cannot be determined. Therefore, a remotely controllable throttle valve connected in parallel to the hydraulic reciprocating actuator 30
At 40, the bypass amount of the AC pressure oil is controlled to obtain a predetermined amplitude (or swing rotation angle). The pressure oil discharged from the A port of the AC fluid pressure pump 20 passes through the hydraulic reciprocating actuator 30, and an equal amount thereof flows in from the B port. Therefore, a spring for pressing the piston 21 against the rotor 22 is not required. Of course, it is better to insert a spring into the cylinder chamber so that the piston 21 always contacts the rotor 22. On the other hand, oil leakage and piston from rotor 22 during high-speed rotation
In order to prevent the 21 from jumping, a constant oil pressure is applied as a preload to the center of the throttle valve 40 as shown in FIG.
Of course, it is needless to say that other portions may be used. The hydraulic oil flowing from the center of the throttle valve 40 passes through the small-diameter hole 23 of the piston 21, lubricates the gap between the rotor 22 and the piston 21, and is returned to the tank 50 as a drain. This AC fluid pressure pump 20 can also obtain a vibration waveform such as a sine wave, a triangular wave, or a trapezoidal wave by changing the shape of the rotor 22. Further, when it is desired to increase the frequency of the vibration, if the rotor 22 is shaped as shown in FIG. 8A, four cycles of AC pressure oil can be obtained by one rotation of the pump. Similarly, an arbitrary waveform can be obtained. Further, as shown in FIG. 8b, a plurality of hydraulic pumps having different waveforms of the discharged AC hydraulic oil can be connected to the hydraulic motor 14 to switch to a desired output waveform. The method of controlling the amplitude and the vibration frequency is to detect the vibration displacement of the vibration table 33 with the displacement detector 60 as shown in FIG. The throttle amount of the throttle valve 40 may be servo-controlled via 70. The hydraulic reciprocating actuator 30 may be configured as a push-pull type cylinder by coupling two single-acting cylinders 31 without spring to a vibration table 33 as shown in FIG. Also, as shown in FIG. 10, the vibration may be applied by the double rod type cylinder 32. The movement of the shaking table 33 is detected by the sensor 60, and the amplitude is determined by controlling the throttle valve 40 via the servo amplifier 70. At the same time, the rotation of the electric motor 12 and the discharge amount of the pressure oil of the variable container hydraulic pump 13 are simultaneously (or individually) controlled, and the discharge frequency of the pressure oil is controlled to determine the vibration frequency. When it is not necessary to change the discharge amount of the pressure oil over a wide range, the AC motor
Can also be driven. As a method of supporting the shaking table 33, two or four piston rods 34 are attached to the shaking table 33 as shown in FIG. The vibration table 33 has a structure supported by an oil film interposed in a gap between the ram piston rod 34 and the hydraulic reciprocating actuator 30. As for the oil film, the pressure oil supplied from the center of the throttle valve 40 in FIG. 9 always flows through the gap between the piston rod 34 and the hydraulic reciprocating actuator 30 to form an oil film, so that there is no problem even if a load is applied. . As the actuator in the case where the vibration waveform of the rock drill, the vibration crusher or the like does not make much of a problem, a single rod type double acting cylinder may be used as shown in FIG. However, in this case, an accumulator 80 may be added to the B port side in order to absorb the difference in oil amount between the A and B ports due to the shape of the single rod. The AC fluid pressure pump 20 shown in FIG.
Taking into account that this has the potential of a later divisional application, it will be described in detail below. An AC fluid pressure pump 20 comprises an elliptical internal rotor 22, a circular external stator 24 inscribed at the long end of the internal rotor 22, and a plurality of pistons 21. The plurality of pistons 21 are movably fitted in cylinder chambers 23 provided in the external stator 24 described above. The internal rotor 22 may be provided at an interval without being inscribed in the external stator 24. The piston 21 is always in contact with the surface of the rotor 22 described above. With the rotation of the internal rotor 22,
The pump function is exerted by reciprocating inside the cylinder chamber 23. The above-mentioned cylinder chamber 23 has a piston 21a.
Are located at the bottom dead center, and the piston 21b is located at the top dead center, indicating that they are paired. Therefore, one piston is a hydraulic reciprocating actuator
When the hydraulic oil is being discharged to 30, the other piston is sucking the hydraulic oil discharged from the hydraulic reciprocating actuator 30. In this embodiment, two pairs of pistons 21 are used, but a plurality of pairs may be used. Although the internal rotor 22 is an elliptical internal rotor in the present embodiment, as described above, in order to obtain the output waveform of the AC pressure oil, the internal rotor 22 does not need to have a substantially elliptical shape having at least a major axis and a minor axis. must not. Further, the piston 21 may have a shape such as a cylindrical shape or a prism shape according to the use as shown in FIG. In addition, it is necessary to consider that the square ridge portion is provided with a rounded shape so as to be always in contact with the rotation of the internal rotor 22. Hydraulic oil is usually mineral oil, but sometimes water. Any non-compressible liquid can be used. (Effect of the Invention) Since the liquid pressure vibrator of the present invention is configured as described above, the vibration frequency can be largely changed at low cost, and the amplitude of vibration can be controlled steplessly. The vibration waveform can be arbitrarily selected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing one embodiment of a fluid pressure vibrator according to the present invention. FIG. 2 is a circuit diagram of one embodiment of a conventional hydraulically driven vibrator. FIG. 3 shows the driving wheels of a steam locomotive. FIG. 4 is a side view of one embodiment of a conventional vibrator using unbalanced weights. FIG. 5 is a side view of one embodiment of a hydraulic pump used in the hydraulic vibrator according to the present invention. FIG. 6 is an explanatory view of an AC fluid pressure piston pump. FIG. 7 is an explanatory diagram of the supply of pre-pressure hydraulic oil for the AC fluid pressure pump of FIG. FIG. 8 is an explanatory diagram of an AC fluid pressure multiple pump. FIG. 9 is obtained by adding a servo control circuit to FIG. FIG. 10 shows a fluid pressure vibrator using a double rod type cylinder as an actuator. FIG. 11 is a side view of one embodiment showing a method of supporting a shaking table. FIG. 12 shows a fluid pressure vibrator using a single rod type double acting cylinder as an actuator. FIG. 13 is a perspective view of various shapes of the piston of FIG. 10 ... variable capacity hydraulic pressure supply device 11 ... inverter 12 ... motor 13 ... variable capacity hydraulic pump 14 ... hydraulic motor 20 ... AC fluid pressure pump 21 ... piston 22 ... rotor 23 ... cylinder Chamber 24 Stator 30 Hydraulic reciprocating actuator 32 Double rod type cylinder 33 Shaking table 34 Piston rod 40 Throttle valve 50 Tank 60 Displacement detector 70 Servo amplifier 80 …… Accumulator

Continuation of the front page (56) References JP-A-61-100637 (JP, A) JP-A-53-143085 (JP, A) JP-A-52-25986 (JP, A) JP-A-55-56872 (JP, A) JP-A-50-43383 (JP, A) JP-A-58-180802 (JP, A) JP-A-50-27170 (JP, A) JP-A-49-105558 (JP, A) 55-31049 (JP, U) Japanese Utility Model 60-185078 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B06B 1/18

Claims (1)

(57) [Claims] In a hydraulic drive vibration device, a prime mover such as an internal combustion engine or an electric motor (12) whose rotational speed can be controlled, an AC fluid pressure pump (20) driven by the prime mover at a variable rotational speed, the AC fluid pressure pump ( 20) The hydraulic reciprocating actuator (30) driven by the hydraulic oil by outputting an AC pressure oil proportional to the rotation speed of the prime mover described above, and driven by the hydraulic reciprocating actuator (30). A vibrating table (33) that is vibrated at the same frequency as the above-mentioned AC pressure oil, and is connected in parallel to the above-mentioned hydraulic reciprocating actuator (30), and controls the bypass amount of the above-mentioned AC pressure oil. A fluid pressure vibrator characterized by comprising a throttle valve (40) capable of changing the amplitude or swing rotation angle of the vibration table (33). 2. In a hydraulic drive vibration device, a prime mover such as an internal combustion engine or an electric motor (12) whose rotational speed can be controlled;
2) The one-way discharge variable displacement hydraulic pump (13) driven to be variable in rotation speed in 2), the capacity of the one-way discharge variable displacement hydraulic pump (13) can be varied without significantly impairing output linearity. An AC fluid pressure pump (20) driven at a speed proportional to the amount of the discharged DC pressure oil while varying the capacity ratio to greatly increase the output, and an output proportional to the rotation speed of the AC fluid pressure pump (20). A hydraulic reciprocating actuator (30) driven by AC hydraulic oil, and a vibration table (33) driven by the hydraulic reciprocating actuator (30) and vibrated at the same frequency as the AC hydraulic oil. ), Which is connected in parallel to the hydraulic reciprocating actuator (30) and controls the bypass amount of the AC pressure oil to change the amplitude or swing rotation angle of the vibration table (33) Throttle valve (40) Hydraulic vibrator which features a thing. 3. The AC fluid pressure pump (20) discharges AC pressure oil in one-way rotation, and the AC fluid pressure pump (20)
Non-circular internal rotor (22) with a major axis and a minor axis
A circular outer stator (24) paired with the inner rotor (22), and a piston which has an even number of cylinder chambers (23) in the outer stator (24) and is fitted into the cylinder chamber (23). The piston (21) discharges two or four cycles of AC pressurized oil per one revolution of its internal rotor (22). 4. The fluid pressure vibrator according to claim 1.