JP4083093B2 - Double-rotating hydraulic pump circuit - Google Patents

Description

  The present invention relates to an improvement of a double-rotating hydraulic pump circuit configured to perform inverter or servo control on an electric motor that drives a double-rotating hydraulic pump.

By controlling the rotation direction and rotation speed of the double-rotating hydraulic pump using inverter control that can freely control the rotation direction and rotation speed using an induction motor, the speed and pressure control of the hydraulic actuator can be controlled. Done. For example, in Patent Document 1, as shown in FIG. 3, a double-rotating hydraulic pump having a pair of suction and discharge ports 1a and 1b that are capable of sucking and discharging liquids, for example, a double-rotating piston pump 1; An induction motor 2 for driving the double-rotating hydraulic pump, an inverter control device 3 for controlling the rotation direction and the number of rotations of the induction motor and controlling the intake / discharge amount of the double-rotating hydraulic pump, A circuit 31 is disclosed in which a hydraulic path is connected to the intake / exhaust port of the pump and further connected to a single rod cylinder 7 which is a hydraulic actuator. In this circuit 31, the discharge and suction amounts of the hydraulic pump 1 are the same, whereas there is a difference in the amount of suction and discharge of the hydraulic cylinder 7. The check valve 6a, 6b is replenished with an insufficient flow rate, and if it is excessive, the pilot check valve 11 is opened and discharged to the tank 20.

Further, when the hydraulic cylinder 7 is subjected to its own weight, pressure is applied to the pilot line 11a of the pilot check valve 11, so that the pilot check valve is opened and pressure control by the pressure on the cylinder head (cap) side 34 becomes impossible. Problems occur. Therefore, a counter balance valve 8 with a check valve is provided to prevent the cylinder 7 from dropping its own weight and the like, and to prevent the pilot check valve from being opened, thereby enabling pressure control.
JP, 9-174300, A FIG. 1, FIG.

However, in Patent Document 1, since the counter balance valve 8a with a check valve is interposed between the cylinder 7 and the pump 1, when the rod 7a is popped out (lowered in the figure), pressure loss is caused by the counter balance valve with the check valve. In addition, waste of energy for supplying the pressurized liquid with the working pressure added to the head side 34 is generated. On the contrary, since the check valve 8b is interposed in the rod-side hydraulic pressure path 35 in the rise, there is an energy loss due to the pressure loss of the check valve, and further, for example, less than the pressure loss of the check valve after canceling its own weight. There was a problem that low pressure control of 0.1 MPa or less was not possible.

  In view of the above problems, the problem of the present invention is to reduce energy loss due to pressure loss or the like under a negative load such as falling due to its own weight. A double-rotating hydraulic pump circuit capable of pressure control is provided.

In the present invention, a double-rotating hydraulic pump having a pair of suction and discharge ports that are capable of sucking and discharging liquid from each other, an electric motor that drives the dual-rotating hydraulic pump, and the rotation direction and rotation of the electric motor A control device configured to control the number of suction and discharge of the double-rotating hydraulic pump, two hydraulic pressure paths respectively connected to the suction and discharge ports of the double-rotating hydraulic pump, and the liquid A check valve provided in each pressure path and connected to be able to suck in hydraulic fluid from a tank; a head-side hydraulic path and a rod-side hydraulic path connected directly to each of the suction and discharge ports in the hydraulic path ; A double-rotating hydraulic pump circuit comprising a single-rod cylinder arranged so that the rod faces upward, and is branched from the head-side hydraulic pressure path and holds the pressure of the head-side hydraulic pressure path; Check bar enabled backflow Has a Bed with counterbalance valve, two connecting ports which are respectively connected to the branch passage branched from the outlet to the rod side hydraulic pressure passage of said check counterbalance valve with a valve, the hydraulic pressure of the rod side is the When the hydraulic pressure at the outlet is greater than or equal to a predetermined value, the connection port connected to the rod-side hydraulic pressure path is disconnected from the tank line, the outlet and the tank line are communicated, and the hydraulic pressure at the outlet is When the fluid pressure on the rod side is equal to or greater than a predetermined value, the connection port connected to the rod side communicates with the tank line, the outlet and the tank line are blocked, and the fluid pressure on the outlet and the rod side Flushing in which all of the outlet, the tank line, the connection port connected to the rod side hydraulic pressure path, and the tank line are blocked when the hydraulic pressure difference is less than a predetermined value. Lube and, has resolved the problems described above by providing both rotary type hydraulic pump circuit provided.

That is, in the present invention, the counter balance valve with a check valve is connected to the head side hydraulic pressure side of the single rod cylinder arranged so that the rod faces upward, while not from the hydraulic pressure path but from the hydraulic pressure path. A counter balance valve with a check valve is provided on the branch path that is branched and connected. Further, the intake / exhaust port is directly connected to the head side hydraulic pressure path and the rod side hydraulic pressure path. Therefore, in the rod pop-out direction (upward direction), the rod side hydraulic pressure path becomes insufficient and negative pressure or tank pressure becomes less, and the back pressure fluctuation is reduced. On the other hand, the head side hydraulic pressure path is used for pressure control while balancing with its own weight. However, since the pump discharge amount does not pass through the check valve, there is no pressure fluctuation due to the check valve, and low pressure control is possible. Further, at the time of lowering, the counter balance valve with check valve is branched, so that part or all of the pump discharge amount and return amount (suction amount) do not necessarily pass through the counter balance with check valve. Therefore, the influence of the spring, structure, flow path, etc. of the counter balance valve with check valve is small. Further, the size of the counter balance valve with check valve may be small.

Moreover, having two connection ports each connected to a branch passage branched from the outlet to the rod side hydraulic pressure passage of said check counterbalance valve with a valve, the hydraulic pressure of the rod side than the fluid pressure of the outlet When the value is equal to or greater than a predetermined value, the connection port connected to the rod side hydraulic pressure path is disconnected from the tank line, the outlet and the tank line are communicated, and the hydraulic pressure at the outlet is equal to the hydraulic pressure at the rod side. More than a predetermined value, the connection port connected to the rod side communicates with the tank line, the outlet and the tank line are shut off, and the hydraulic pressure difference between the rod side and the outlet is predetermined. When the value is less than the value, the outlet, the tank line, the connection port connected to the rod-side hydraulic pressure path, and the tank line are both flush rotary valves configured to be a flushing valve. And the amplifier circuit. As a result, when descending, pressure liquid is supplied to the rod side hydraulic pressure path, the outlet and the tank line are communicated, and only the excess liquid in the head side hydraulic pressure path is tanked via the counter balance valve with check valve. Lower by releasing. At the time of ascent, it does not pass through the check valve as described above. Further, at the time of rise, the deficiency liquid fraction generated in the rod side hydraulic pressure passage, in addition to be self-priming from the tank via a switch Ekkubarubu 6a, from the connected access port to the passed through tank line and communicating the rod-side also Ri Do and be self-priming, Ji Ekkubarubu 6a may be relatively small in size.

  The flushing valve is used in a closed circuit that directly connects a hydraulic pump and a hydraulic motor, which are often used in vehicles, etc. Often used as a replacement control valve. In the present invention, the characteristics of the flushing valve are used as they are. That is, the flushing valve has two connection ports. When the hydraulic pressure on one side (rod side) is equal to or higher than the hydraulic pressure on the other side (outlet), one hydraulic pressure path is disconnected from the tank line. The load side of the hydraulic motor is closed, the connection port connected to the other (exit) communicates with the tank line, and a part of the pressure oil on the return side of the hydraulic motor is returned to the tank. The same applies to the reverse case, where the low pressure side is connected to the tank and the high pressure side is closed. Further, when the hydraulic pressure difference between the one (rod side) and the other (exit) hydraulic pressure is less than a predetermined value, the tank line is shut off.

In the present invention, a counter balance valve with a check valve is provided in the branch side of the head side hydraulic pressure path of the single rod cylinder, the generated pressure loss is reduced, and the pressure fluctuation due to the check valve is eliminated to enable low pressure control. Therefore, a double-rotating hydraulic pump circuit that reduces the energy loss due to negative load pressure loss, etc., enables low-pressure control when pressurizing against the dead weight in the rod pop-out direction, and can control a wide range of pressure is provided. It became something to do. In addition, the counter balance valve with check valve can be made smaller, and the entire apparatus can be made smaller .

Furthermore, using the flushing valves used in vehicles or the like, downsizing, to eliminate the excess or deficiency to drain intake of the pump from the tank to replenish or tank, further reducing the pressure loss, self-suction performance Increased. Furthermore, it became energy efficient. In addition, since a general flushing valve itself can be used, it is commercially available and the cost can be reduced. Furthermore, the flushing valve and the counter balance valve with a check valve are small and can be easily laminated, so that the assembly is simple and the size can be further reduced.

Embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 is a reference circuit diagram of a double-rotating hydraulic pump circuit 21 using a pilot check valve . Note that parts similar to those in FIG. In FIG. 1, a piston-type bi-rotary hydraulic pump 1 having a pair of intake / exhaust ports capable of sucking and discharging liquid from each other, an induction motor 2 for driving the bi-rotary hydraulic pump, and rotation of the induction motor The inverter control device 3 that controls the direction and the number of rotations to control the intake and discharge amount of the double-rotation hydraulic pump, and two liquids connected to the intake and discharge ports 1a and 1b of the double-rotation hydraulic pump, respectively. a pressure passage 4,5, respectively provided tank 20 hydraulic fluid from the tank is sucked connected to the switch Ekkubarubu 6a, 6b in the liquid pressure passage is directly connected to the respective intake ports 1a, 1b in the liquid pressure passage And a single rod cylinder 7 which is a hydraulic actuator. The cylinder 7 is arranged so that the rod 7a faces upward. The rod 7a of the single rod cylinder 7 is provided with a position sensor 15 such as a linear sensor and a load sensor 16, and is fed back to the inverter control circuit 3 to control the induction motor 2 in accordance with a predetermined pressure, direction and speed command control device. In addition, the rotational direction and the rotational speed of the rotary hydraulic pump 1 are controlled so that a predetermined operation can be performed. A load (not shown) is applied to the rod 7a, and a load is applied downward as seen in the figure. A counter balance valve 8 with a check valve is branchedly connected to the head side hydraulic pressure passage 5, and the pilot check valve 11 is arranged between the outlet 9 and the tank 20 in a direction in which hydraulic fluid can flow from the tank side to the outlet side. The hydraulic fluid can be returned from the outlet 9 to the tank 20 by supplying pressure to the pilot line 11a. A pilot line 11 a of a pilot check valve 11 is connected to the rod side hydraulic pressure passage 4.

Next , the operation of FIG. 1 will be described. A pressure corresponding to the weight of the cylinder 7 is applied to the head-side hydraulic path 5 by its own weight. The counter pressure of the counter balance valve with check valve 8 is set at a pressure slightly higher than the self-weight converted pressure. When stopping, the cylinder 7 is maintained by the pump 1 and the counter balance valve 8 with a check valve. At the time of ascent, pressure fluid (oil) is supplied from the pump 1 to the head side 5 to raise the cylinder 7. The cylinder discharge liquid from the rod side 4 is sucked from the rod side 1a of the pump 1, but the amount of liquid is insufficient regardless of the pressure on the head side 5 and therefore the insufficient liquid is discharged from the tank 20 via the check valve 6a. Inhaled. In particular, at the time of ascent and pressurization, the rod side 4 is at the tank pressure, and there is no valve such as the check valve 8b from the pump discharge port 1b to the head side hydraulic pressure port 5 of the cylinder 7. The pressure control can be performed delicately and over a wide range. Needless to say, in order to perform low-pressure or high-precision pressure control, it is preferable to use a cylinder capable of low-pressure operation that is not affected by pressure.

  At the time of lowering, the hydraulic pressure is sucked and lowered from the pump port 1b connected to the head side hydraulic pressure path 5. Since the amount of pump oil supplied to the rod side 4 is substantially the same as that of the head side 5, the rod side 4 becomes high pressure, the pilot check valve 11 opens, the outlet 9 of the counter balance valve 8 with check valve and the tank line 10 are connected. As a result, the excess liquid in the head-side hydraulic path 5 is discharged to the tank 20.

Next , embodiments of the present invention will be described with reference to the drawings. Figure 2 is a circuit diagram of the two rotary type fluid pressure pump circuit 22 using shown to hula Sshingubarubu 11 'an embodiment of the present invention. This is different in that a so-called flushing valve 11 'is used in place of the pilot check valve 11 of FIG. 1 , and the other parts are the same, and parts similar to those in FIG. 1 and FIG. A part of the description is omitted. In FIG. 2, the flushing valve 11 ′, which is a flow path selection valve, is a spool type switching valve, and is connected to the outlet 9 of the counter balance valve 8 with check valve and the branch path 4 a branched from the rod side hydraulic path 4. The two connection ports thus formed, the connection port connected to the tank line 10, and a closed port 17 are provided. When the hydraulic pressure at the outlet 9 is equal to or higher than a predetermined value on the rod side 4 hydraulic pressure, the position a shown in FIG. 2 is reached, and the outlet 9 communicates with the closing port 17 and is disconnected from the tank line 10. The connection port 4a connected to the pressure path and the tank line 10 are communicated with each other. When the fluid pressure on the rod side 4 is greater than the fluid pressure at the outlet 9, the position b is shown in FIG. 2, and the outlet 9 communicates with the tank line 10 and the connection port 4 a connected to the rod side 4 is closed. The port 17 communicates with the tank line 10. When the hydraulic pressure difference between the outlet 9 and the hydraulic pressure on the rod side 4 is less than a predetermined value, that is, when neutral, the position c is shown in FIG. 2, and the outlet 9, the tank line 10, and the rod side hydraulic pressure path The connection port 4a and the blocking port 17 connected to each other are blocked, so-called all-port block.

Illustrating the operation of the implementation of the embodiment of the present invention. Since it operates in the same manner as described above at the time of stopping and descending, its description is omitted. At the time of ascent, pressure fluid (oil) is supplied from the pump 1 to the head side 5 to raise the cylinder 7. The cylinder discharge liquid from the rod side 4 is sucked from the rod side 1a of the pump 1, but the amount of liquid is insufficient regardless of the pressure on the head side 5 and therefore the insufficient liquid is discharged from the tank 20 via the check valve 6a. In addition to being inhaled, the self-priming performance is enhanced because it is also inhaled from the tank 20 through the flushing valve 11 '.

It is a reference circuit diagram of a double-rotation hydraulic pump circuit using a pilot check valve. It is a circuit diagram of a double rotation type hydraulic pump circuit using a flushing valve showing an embodiment of the present invention. It is a circuit diagram of a conventional double-rotating hydraulic pump circuit.

Explanation of symbols

1 Both rotary type hydraulic pump 1a, 1b intake port 2 motor 3 controller 4 rod side fluid pressure passage 4a rod side hydraulic path connected to a connection port 5 the head side hydraulic pressure passage 6a, 6 b Chi Ekkubarubu 7 pieces rod Cylinder 8 Counter balance valve with check valve 9 Outlet of counter balance valve with check valve
10 Tank line
11 'Flushing valve 20 Tank
22 Double-rotating hydraulic pump circuit

Claims (1)

A double-rotating hydraulic pump having a pair of suction and discharge ports capable of mutually sucking and discharging liquid; an electric motor that drives the double-rotating hydraulic pump; and a rotational direction and a rotational speed of the electric motor, A control device configured to control the intake / exhaust amount of the double-rotating hydraulic pressure pump, two hydraulic pressure paths connected to the intake / exhaust ports of the double-rotating hydraulic pressure pump, and the hydraulic pressure path, respectively. The check valve is connected to the tank so that hydraulic fluid can be sucked, and the hydraulic pressure path includes a head side hydraulic pressure path and a rod side hydraulic pressure path directly connected to the suction / exhaust port, and the rod faces upward. A double-rotating hydraulic pump circuit having a single-rod cylinder arranged in such a manner that it is branched from the head-side hydraulic pressure path and is capable of holding and backflowing the pressure in the head-side hydraulic pressure path Counter rose with check valve And Subarubu, wherein each checked counterbalance outlet of the valve with the valve and the branch passage branched from the rod-side hydraulic pressure passage has connected the two connection ports, the rod side of the hydraulic pressure of the outlet fluid pressure When the value is greater than or equal to a predetermined value, the connection port connected to the rod-side hydraulic pressure path is disconnected from the tank line, the outlet and the tank line are communicated, and the hydraulic pressure at the outlet is adjusted to the liquid pressure on the rod side. When the pressure is greater than or equal to a predetermined value, the connection port connected to the rod side communicates with the tank line, the outlet and the tank line are blocked, and the hydraulic pressure difference between the outlet and the hydraulic pressure on the rod side is The outlet, the tank line, the connection port connected to the rod-side hydraulic pressure path, and the flushing valve configured to block all of the tank line when less than a predetermined value; Both rotary type fluid pressure pump circuit characterized and.

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