JP2011214598A - Hydraulic control circuit for double-acting cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in a conventional hydraulic control circuit for a double-acting cylinder wherein costs become high since four solenoid valves are necessary for carrying out vertical operation of a rod 3b, and space also becomes larger for housing four solenoid valves.SOLUTION: The hydraulic control circuit for a double-acting cylinder comprises a motor pump 2 supplying oil to a hydraulic circuit from an oil tank 1, first and second serially connected solenoid valves 4, 5, a check valve 11 connected between an oil inlet side of the second solenoid valve and the motor pump and allowing passage of oil from the motor pump, a check valve 10 serially connected to the second solenoid valve, and the double-acting cylinder 3 having a cylinder 3a of side delivering the rod 3b connected to a connection point with an oil inflow side of the first solenoid valve and a cylinder of a side housing the rod connected to a side of the second solenoid receiving inflow of the oil.

Description

  The present invention is, for example, a double-acting mechanism for tilting a seat of a barber / beauty chair or a medical chair, or for opening / closing a support in a delivery table for obstetrics and gynecology, or for rotating the entire delivery table. The present invention relates to a hydraulic control circuit for a double-acting cylinder in which the number of solenoid valves used in the hydraulic control circuit is two 2-port solenoid valves for one double-acting cylinder.

  As a conventional hydraulic control circuit for a double acting cylinder, there is a hydraulic control circuit shown in FIG. 1 is an oil tank, 2 is a motor pump, 3 is a double-acting cylinder for performing the tilting operation of the seat, the opening / closing operation of the support, or the rotation operation of the delivery table, and 4-7 are 2-port solenoid valves ( Hereinafter, it is simply referred to as a solenoid valve). In addition, 8 is a relief valve, 9 is a throttle valve, and 10 is a check valve. In the double acting cylinder 3, 3a is a cylinder, and 3b is a rod.

  In the hydraulic circuit, the solenoid valves 4, 5, 6 and 7 are connected in series, and the solenoid valves 4, 5, 6 and 7 and the relief valve 8 connected in series are connected to the motor pump 2 and oil connected in series. The tank 1 is connected in parallel. The lower side of the cylinder 3a of the double acting cylinder 3 is connected to a connection point with the solenoid valves 4 and 5 by an oil pipe, and the rod 3b side is connected to a connection point with the solenoid valves 6 and 7 by an oil pipe. . The throttle valve 9 is connected in series with each of the electromagnetic valves 4 to 7, and the check valve 10 is connected between the electromagnetic valves 5 and 7 and the throttle valve 9.

  Next, in order to explain the operation of the hydraulic control circuit, the electromagnetic valves 5 and 6 are opened by an electric control circuit (not shown) to open the rod of the double acting cylinder 3. When the motor pump 2 is driven in this state, the oil sucked from the oil tank 1 and pressurized by the motor pump 2 passes under the cylinder 3a of the double acting cylinder 3 through the solenoid valve 5, the check valve 10 and the throttle valve 9. Oil is supplied into the side and the rod 3b moves in the discharge direction. By this movement, the tilting operation of the seat part and the opening / closing operation of the support are performed.

  At this time, since oil is collected on the rod 3b side of the cylinder 3a, the oil is discharged as the rod 3b moves, but the solenoid valve 6 is in an open state. The oil is returned to the oil tank 1 through the valve 9. When the sensor for detecting the upward tilting operation of the seat and the opening operation of the support leg detects a preset value, the electric control circuit cuts off the energization of the electromagnetic valves 5 and 6 and discharges the rod 3b. Stop. Thereby, the upward movement of the tilt of the seat and the opening operation of the support leg are completed.

  On the other hand, in order to lower the rod 3b in the discharge state, the solenoid valves 4 and 7 are opened and the motor pump 2 is driven, so that the pressurized oil from the motor pump 2 is solenoid valve 7, check valve 10, throttle Since it is supplied to the upper rod 3b side of the cylinder 3a in the double acting cylinder 3 through the valve 9, the rod 3b starts to descend and the oil stored below the cylinder 3a passes through the electromagnetic valve 4 and the throttle valve 9. Through the oil tank 1. When the sensor for detecting the downward tilting movement of the seat and the closing movement of the support leg detects a preset value, the electric control circuit cuts off the energization of the electromagnetic valves 5 and 6 and stops the discharge of the rod 3b. Let As a result, the upward movement of the seat tilt and the closing operation of the support leg are completed.

  In the conventional hydraulic control circuit for a double-acting cylinder, four solenoid valves are required to move the rod 3b up and down, so that the cost is high and four solenoid valves are required. There was a problem that the space for accommodating the space also increased.

  Therefore, there is an invention described in Japanese Patent Application Laid-Open No. 6-23003 as a solenoid valve having a reduced number. The present invention discloses a hydraulic circuit for waking up a backrest. By opening the solenoid valves 28 and 29 and closing the solenoid valve 30 to drive the motor pump 27, the pressure oil is used for driving transmission. The oil flows into the compartment 5a of the cylinder (double-acting cylinder) and moves the piston rod 6 to the right, so that the piston rod 12 of the distribution cylinder 11 moves to the right and oil flows into the compartment 16b of the working cylinder 16. The backrest rotates in the prone direction.

  In order to turn the backrest in the upright direction, the solenoid valves 29 and 30 are opened, the solenoid valve 28 is closed, and the motor pump is driven so that the pressure oil flows into the section 5b of the drive transmission cylinder. The piston rod 6 moves to the left and the piston rod 12 also moves to the left, so that oil flows into the section 16a of the working cylinder 16 and the backrest rotates in the standing direction.

JP-A-6-23003

  By the way, in the technical idea of the above-mentioned patent publication, although it is reduced to three as a two-port solenoid valve with respect to four two-port solenoid valves in the hydraulic circuit of FIG. There was a problem that a solenoid valve unit composed of two 2-port solenoid valves could not be used, resulting in an increase in cost and a large space. When a 4-port solenoid valve is used, two solenoid valves are sufficient, but the cost of the 4-port solenoid valve is much higher than that of the 2-port solenoid valve.

  The present invention is intended to solve the above-mentioned problems, and the object of the present invention is to control a double-acting cylinder by using two 2-port solenoid valves in a double-acting cylinder hydraulic control circuit. It is an object of the present invention to provide a hydraulic control circuit for a double-acting cylinder that can reduce the cost and reduce the space for the hydraulic device as compared with the conventional hydraulic control circuit using four or three two-port solenoid valves. .

  The hydraulic control circuit for a double-acting cylinder according to the present invention achieves the above-described object, and the means of claim 1 includes a motor pump that supplies oil from an oil tank to a hydraulic circuit and is connected in series with a motor pump. 1, a second solenoid valve, a check valve connected between the oil inlet side of the second solenoid valve and the motor pump, through which oil from the motor pump can pass, and the second solenoid valve A cylinder on the discharge side of the rod is connected to a connection point between the check valve connected in series and the oil inflow side of the first solenoid valve, and the rod is connected to the side of the second solenoid valve on which the oil flows. It is characterized by comprising a double-acting cylinder to which a cylinder on the storage side is connected.

  The means of claim 2 includes a motor pump for supplying oil from an oil tank to a hydraulic circuit, first and second solenoid valves connected in series, an oil inlet side of the second solenoid valve, and the motor pump. A check valve that is connected between the check valve and allows oil from the motor pump to pass therethrough, a check valve connected in series to the second solenoid valve, and a connection point between the oil inflow side of the first solenoid valve A third cylinder connected in series with a first double-acting cylinder in which a cylinder on the side for discharging the rod is connected to the cylinder, and a cylinder on the side for housing the rod is connected to the side on which oil flows into the second solenoid valve. , A fourth solenoid valve, a check valve connected between the oil inflow side of the fourth solenoid valve and the motor pump, through which oil from the motor pump can pass, the check valve and the third valve A cylinder for discharging the rod is connected to a connection point of the solenoid valve with the oil inflow side, Characterized in that the side of the cylinder for accommodating the rod on the side for flowing the oil solenoid valve is composed of a second double-acting cylinders connected.

  According to a third aspect of the present invention, there is provided a motor pump for supplying oil from an oil tank to a hydraulic circuit, a relief valve connected between the motor pump and an oil drain pipe, and first and second connected in series. A solenoid valve and third and fourth solenoid valves; a throttle valve connected in series to the oil tank and the first and third solenoid valves; an oil inflow side of the second and fourth solenoid valves; and the motor A check valve connected between the pump and the oil from the motor pump, a check valve and a throttle valve connected in series with the second and fourth solenoid valves, and a first solenoid valve A first double-acting cylinder in which a cylinder for discharging the rod is connected to the oil inflow side, and a cylinder for storing the rod is connected to the oil inflow side of the second solenoid valve; and the third electromagnetic A cylinder on the side that discharges the rod is connected to the oil inflow side of the valve, and the oil of the fourth solenoid valve The second double-acting cylinder is connected to the cylinder on the inflow side which accommodates the rod, and the pressure of the oil including the cylinder on the side accommodating the rod in the first and second double-acting cylinders is increased. As described above, the throttle valve 9 connected to the second and third solenoid valves increases the flow rate so that the pressure on the side where the rod is accommodated does not decrease. The double-acting cylinder is prevented from becoming unstable on the side where the rod is housed.

  According to a fourth aspect of the present invention, in any one of the first to fourth aspects, the proportional solenoid valve is connected to the cylinder on the side that discharges the rod in each of the solenoid valves and the double-acting cylinder, and the rod in each double-acting cylinder is started. And the speed at the time of a stop is made to perform slowly.

  In the present invention, as described above, the connecting portion of the solenoid valves connected in series is connected to the cylinder side that discharges the rod of the double-acting cylinder, and the side that houses the rod of the cylinder is connected to the motor pump. A check valve is connected in the direction in which oil from the motor pump flows between the oil inflow side of the solenoid valve and the motor pump, and the double-acting cylinder is connected by two solenoid valves. Since the rod can be discharged and stored, the number of solenoid valves can be halved compared to the conventional case, so that the cost can be reduced and the space of the hydraulic device can be reduced.

  Also, even if two double-acting cylinders are individually driven by using two solenoid valves and connecting the solenoid valves individually via check valves, the influence on other double-acting cylinders Therefore, even if two double-acting cylinders are driven, they can be controlled without interfering with each other.

  Further, in order to control the two double-acting cylinders separately by using the conventional four-pole solenoid valve, the pressure of the mixed oil including the cylinder on the side of housing the rod in the two double-acting cylinders is reduced. By increasing the flow rate with the throttle valve connected to the solenoid valve 2 so as to increase so that the pressure on the side that houses the rod does not decrease, other double-acting cylinders operate during the operation of each double-acting cylinder It is possible to prevent the side where the rod is stored from becoming unstable.

  Further, by connecting a proportional solenoid valve to each solenoid valve and the cylinder on each double-acting cylinder that discharges the rod, the speed at the start and stop of the rod in each double-acting cylinder can be reduced. It is what has.

It is a hydraulic circuit which shows the basic composition which controls one double acting cylinder of this invention. This is a hydraulic circuit for controlling two double-acting cylinders. This is a hydraulic circuit for controlling one single-acting cylinder and two double-acting cylinders. It is a timing chart of the hydraulic circuit of FIG. 2 is a hydraulic circuit in which a proportional control valve is incorporated in the hydraulic circuit of FIG. 1 to perform slow start and slow stop. This is a hydraulic circuit that controls one conventional double-acting cylinder.

Hereinafter, a basic structure for tilting a seat portion will be described with reference to FIG. The same reference numerals as those of the conventional example of FIG.
6 differs from FIG. 6 in that the solenoid valves 6 and 7 and the throttle valve 9 in FIG. 11 and the check valve 11 is connected to an oil pipe from the motor pump 2 to which the oil inlet side of the electromagnetic valve 5 and the relief valve 8 are connected.

  The piston area S1 of the cylinder 3a in the double-acting cylinder 3 and the rod-side area S2 obtained by subtracting the rod-side cross-sectional area from the piston area on the rod 3b side have a relationship of S1> S2. When S1: S2 = 2: 1, the rod exit and entry speed are the same.

  Next, when the electromagnetic valve 5 is opened and the motor pump 2 is driven, the oil from the motor pump 2 passes through the check valve 11, the electromagnetic valve 5, and the check valve 10 in the double-action cylinder 3 as shown by thin lines. It is supplied to the lower side of the cylinder 3a. In this state where the oil is supplied, the volume S2 on the rod 3b side is smaller than the volume S1, so the thrust on the S1 side exceeds the thrust on the S2 side, and the oil staying on the rod 3b side is discharged, and the motor pump 2 The oil is mixed with the oil and supplied to the lower side of the cylinder 3a through the electromagnetic valve 5, and the rod 3b is raised.

  The oil from the motor pump 2 and the oil returned from the upper side of the double-acting cylinder 3 are supplied to the lower side of the cylinder 3a in the double-acting cylinder 3, thereby increasing the amount of oil and raising the rod 3b. Increases speed.

  An electric control circuit (not shown) monitors whether or not the discharge amount of the rod 3b has reached a preset discharge amount. When it is determined that the discharge amount has been reached, the energization to the motor pump 2 and the electromagnetic valve 5 is stopped. The ascent of the rod 3b stops, and the seat portion stops while shifting upward.

  Next, when the electromagnetic valve 4 is opened and the motor pump 2 is driven, the oil from the motor pump 2 is supplied to the rod 3b side of the double-acting cylinder 3 through the check valve 11 as shown by the thick line. The oil staying under the cylinder 3a by the supply of the oil is returned to the oil tank 1 through the electromagnetic valve 4, so that the rod 3b starts to descend.

  Since the electric control circuit monitors whether or not the lowering amount of the rod 3b has reached a predetermined lowering amount, if it is determined that it has reached, the energization to the motor pump 2 and the electromagnetic valve 4 is stopped and the rod 3b is stopped. Descent stops, and the seat moves down and stops.

Next, a hydraulic control circuit for performing, for example, the tilting operation of the seat and the raising / lowering operation of the backrest in the delivery table for obstetrics and gynecology will be described with reference to FIG.
This hydraulic circuit is a compound for causing the back and forth movement of the hydraulic circuit of one double-acting cylinder 3 and two solenoid valves 4 and 5 for tilting the seat. The operation cylinder 31 is added and the two solenoid valves 41 and 51 are connected to the oil tank 1 side on the oil discharge side of the solenoid valve 41, and the oil inflow side of the solenoid valve 51 is connected to the check valve 12. It is connected to the motor pump 2 side.

  Next, the operation of this hydraulic circuit will be described. Since the operation of the double-acting cylinder 3 is the same as that shown in FIG. In order to discharge the rod 31b of the double acting cylinder 31, when the motor pump 2 and the electromagnetic valve 51 are energized, the oil from the motor pump 2 passes through the check valve 12, the electromagnetic valve 51, and the check valve 10 to the cylinder 31a. Since oil is supplied to the lower side, the rod 31b starts discharging.

  On the other hand, the oil staying on the upper side of the cylinder 31a by the discharge of the rod 31b is supplied to the lower side of the cylinder 31a through the solenoid valve 51 and the check valve 10, so that the rod 31b discharges. The backrest changes in the standing direction, and the electric control circuit monitors whether or not the discharge amount of the rod 31b has reached a preset discharge amount. Is stopped, the raising of the rod 31b is stopped, and the backrest is stopped in an upright state.

  Next, in order to return the backrest to the prone direction, the motor pump 2 and the solenoid valve 41 are energized so that the oil from the motor pump 2 passes above the cylinder 31a in the double-action cylinder 31 via the check valve 12. Since oil flows in, the rod 31b starts to descend, and the backrest starts to shift in the prone direction.

  On the other hand, the oil staying under the cylinder 31 a is pushed out and returned to the oil tank 1 through the electromagnetic valve 41 and the throttle valve 9. Since the electric control circuit monitors whether or not the lowering amount of the rod 31b has reached a predetermined lowering amount, if it is determined that it has reached, the energization to the motor pump 2 and the electromagnetic valve 41 is stopped and the rod 31b is stopped. Descent stops, and the backrest stops horizontally.

  2, the electromagnetic valves 4 and 5 are connected through the check valve 11 and the electromagnetic valves 41 and 51 are connected through the check valve 12. The moving cylinders 3 and 31 individually receive and discharge oil, so that the oil flows do not interfere with each other.

  Next, a third embodiment in which the double-acting cylinders 3, 31 and the single-acting cylinder 32 shown in FIG. 3 are connected will be described. The double-acting cylinder 3 will be described as an example of a delivery table lying down and lying down, the double-acting cylinder 31 as an opening / closing operation of a delivery table support, and the single-acting cylinder 32 as a seat raising / lowering cylinder. Further, the solenoid valves 4 and 5 are connected to the double-acting cylinder 3, the solenoid valves 41 and 51 are connected to the double-acting cylinder 31, the solenoid valves 42 and 52 are connected to the single-acting cylinder 32, and the oil inflow side of the solenoid valves 5 and 51 is connected. It is connected to the motor pump 2 through one check valve 11.

  The solenoid valves 4, 5, 41, 51 used in this embodiment are integrated with a conventional quadruple solenoid valve, and the cost is low. In order to construct the above-described circuit of FIG. 2 using this quadruple solenoid valve, it is necessary to connect the check valve 12, but the check valve is added to the conventionally used quadruple solenoid valve. Connecting 12 requires additional work or additional parts.

  As described above, the hydraulic circuit in which the use of the check valve 12 is difficult and no additional work or additional parts are used is shown in FIG. By adopting such a hydraulic circuit, when the rod 31b of one double-acting cylinder, for example, the double-acting cylinder 31, enters and exits, the rod 31b is made to enter and exit with little influence on the other double-acting cylinder 3. Is possible.

  Hereinafter, the operation will be described together with the chart of FIG. 4. In the operation of discharging the rod 31b of the double acting cylinder 31, when the operation switch a (not shown) is operated, the motor pump 2 is energized and a slight time lag is generated. Later, the solenoid valve 51 is energized. By this energization, the rod 31b of the double acting cylinder 31 is discharged by the operation of FIG. 2 described above, and the oil staying above the cylinder 31a is again supplied to the lower side of the cylinder 31a through the electromagnetic valve 51. Therefore, the rod 31b operates in the discharge direction.

  However, in the embodiment of FIG. 3, the oil staying on the upper side of the cylinder 31a of the double-acting cylinder 31 is returned to the solenoid valve 51 and also on the upper side of the cylinder 3a in the other double-acting cylinder 3 via an oil pipe. Therefore, oil tends to flow to the upper side of the cylinder 3a.

  By the way, since the double acting cylinder 31 is used for opening and closing the support, the pressure on the upper side of the cylinder 31a is low because no external force is applied to the rod 31b as in the case of raising and lowering the seat. Is in a low state. Further, the double-acting cylinder 3 is used for lying down on the delivery table, and when the patient's back load is applied to the backrest, the rod 3b is loaded with the patient's back load. In order for 31b not to move, the pressure of B section needs to be high.

  As described above, when the upper pressure of the cylinder 3a in the double-action cylinder 3 is higher than the upper pressure of the cylinder 31a in the double-action cylinder 31, the rod 3b tends to move in the discharge direction by decreasing the upper pressure of the cylinder 3a. Will be born and become unstable.

  In order not to cause such an unstable state, the flow rate is increased by the throttle valve 9 on the oil outlet side of the solenoid valve 51 so that the pressure of the mixed oil including the upper side of the cylinder 3a always increases, thereby increasing the cylinder pressure. The pressure on the upper side of 3a is not lowered. The relief valve serves to keep the inside of the circuit below a certain pressure and to release a higher pressure. By making the relief valve always work, both the upper side of the cylinder 3a and the upper side of the cylinder 31a are pressurized. It is possible to prevent the cylinder 3b from becoming unstable because no change occurs.

  Also, in the operation of energizing the motor pump 2 and the solenoid valve 41 and storing the rod 31b of the double-acting cylinder 31 on the cylinder 31a side, the throttle valve 9 on the oil outlet side of the solenoid valve 41 is adjusted to adjust the pressure in the A part. By increasing the height, it is possible to prevent the rod 3b from moving in the same manner as described above.

  It should be noted that the rod 3b in the double-acting cylinder 3 also moves in and out of the solenoid valves 4 and 5 on the oil outlet side so that the rod 31b of the double-acting cylinder 31 does not move in the same manner as the operation of the double-acting cylinder 31 described above. This can be done by adjusting the throttle valve.

  In FIG. 3, the single-acting cylinder 32 is connected in parallel to the double-acting cylinders 3 and 31, but the single-acting cylinder 32 does not affect the double-acting cylinders 3 and 31 in any way.

  FIG. 5 shows the proportional solenoid valve 13 connected to the connecting portion between the cylinder 3a of the double acting cylinder 3 and the solenoid valves 4 and 5 in the hydraulic circuit of FIG. With such a configuration, when oil is injected from the lower side or the upper side of the cylinder 3a in the double-acting cylinder 3, the speed at the start and stop of the rod 3b can be moderately performed.

  In the embodiment of FIG. 5, the case where a proportional solenoid valve is connected to the hydraulic circuit shown in FIG. 1 has been described. However, the cylinders 3a and 31a in the double acting cylinders 3 and 31 in the embodiment of FIGS. Even when a proportional solenoid valve is connected to the connection portion between the valves 4 and 5 and the solenoid valves 41 and 51, the speed at the start and stop of the rods 3b and 31b can be moderately performed.

1 Oil tank 2 Motor pump 3 Double acting cylinder 3a Cylinder 3b Rod 4, 5 Solenoid valve 8 Relief valve 9 Throttle valve 10, 11 Check valve

Claims (4)

A motor pump that supplies oil from the oil tank to the hydraulic circuit;
First and second solenoid valves connected in series;
A check valve connected between the oil inlet side of the second solenoid valve and the motor pump, through which oil from the motor pump can pass;
A check valve connected in series to the second solenoid valve;
A cylinder on the side that discharges the rod is connected to a connection point with the oil inflow side of the first solenoid valve, and a cylinder on the side that houses the rod is connected to the side that flows in oil of the second solenoid valve. A double acting cylinder;
A hydraulic control circuit for a double-acting cylinder characterized by comprising: A motor pump that supplies oil from the oil tank to the hydraulic circuit;
First and second solenoid valves connected in series;
A check valve connected between the oil inlet side of the second solenoid valve and the motor pump, through which oil from the motor pump can pass;
A check valve connected in series to the second solenoid valve;
A cylinder on the side that discharges the rod is connected to a connection point with the oil inflow side of the first solenoid valve, and a cylinder on the side that houses the rod is connected to the side that flows in oil of the second solenoid valve. A first double acting cylinder;
Third and fourth solenoid valves connected in series;
A check valve connected between the oil inflow side of the fourth solenoid valve and the motor pump, through which oil from the motor pump can pass;
A cylinder on the side that discharges the rod is connected to a connection point between the throttle valve and the oil inflow side of the third solenoid valve, and a cylinder on the side that stores the rod on the side of the fourth solenoid valve that flows in oil A second double acting cylinder connected to
A hydraulic control circuit for a double-acting cylinder characterized by comprising: A motor pump that supplies oil from the oil tank to the hydraulic circuit;
A relief valve connected between the motor pump and the oil drain pipe;
A first and a second solenoid valve and a third and a fourth solenoid valve connected in series;
A throttle valve connected in series to the oil tank and the first and third solenoid valves;
A check valve connected between the oil inflow side of the second and fourth solenoid valves and the motor pump, through which oil from the motor pump can pass;
A check valve and a throttle valve connected in series to the second and fourth solenoid valves;
A first double-acting cylinder in which a cylinder for discharging the rod is connected to the oil inflow side of the first solenoid valve, and a cylinder for storing the rod is connected to the oil inflow side of the second solenoid valve. When,
A second double-acting cylinder in which a cylinder for discharging the rod is connected to the oil inflow side of the third solenoid valve, and a cylinder for storing the rod is connected to the oil inflow side of the fourth solenoid valve When,
The throttle valve 9 connected to the second and third solenoid valves increases the flow rate so that the oil pressure including the cylinders on the rod housing side in the first and second double acting cylinders increases. By preventing the pressure on the side that houses the rod from decreasing by increasing the throttle pressure, the side where the rods of other double acting cylinders are housed is prevented from becoming unstable during the operation of each double acting cylinder. A hydraulic control circuit for a double-acting cylinder.   A proportional solenoid valve is connected to each solenoid valve and a cylinder on each double-acting cylinder that discharges a rod, so that the speed at the start and stop of the rod in each double-acting cylinder can be performed slowly. A hydraulic control circuit for a double-acting cylinder according to any one of claims 1 to 3.

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