JP4753991B2 - Damping coefficient switching type hydraulic damper - Google Patents

Description

  The present invention relates to a hydraulic damper for vibration control for reducing the shaking of a building due to an external vibration force such as an earthquake or wind.

In this type of damping hydraulic damper, for example, as disclosed in Patent Document 1 or Japanese Patent Application No. 2003-303317, an open / close installed in a flow path connecting hydraulic chambers provided on both sides of a piston that reciprocates in a cylinder. There is a damping coefficient switching type hydraulic damper in which a valve opens and closes according to a pressure change in a hydraulic chamber and switches a damping coefficient. In this hydraulic damper, a buffer is connected to the pilot operating part of the on-off valve, and the pressure accumulated in the buffer is used as the driving force of the on-off valve, so that it has good energy absorption capability without using a pressure sensor or an electric control circuit It is possible to get.
JP 2003-56633 A

  In the case of the hydraulic circuit described in Patent Document 1 or Japanese Patent Application No. 2003-303317 described above, there are the following problems to be solved.

(1) Although a poppet valve is used as an on-off valve, the poppet valve always has a crack load (the pressure at which the valve starts to open when the circuit pressure increases). Even if the pilot piston of the pilot operating section operates, the essential on-off valve does not open, and there is a problem that the control performance at a minute vibration level such as wind load is deteriorated.

(2) Also, since the hydraulic pressure accumulated in the buffer is used as the driving force for the pilot piston, there is a risk of a malfunction on the dangerous side, such as when the pressure remains in the buffer, the open / close valve remains open.

(3) On the other hand, paying attention to the configuration of the hydraulic circuit, in the hydraulic circuit shown in the above-mentioned literature, etc., if it is attempted to control the movement in both directions of the piston with a single on-off valve and pilot operation unit, 4 Rectification with two check valves is required. In order to avoid such rectification by the check valve, an independent hydraulic circuit is required for each of the left and right sides, both of which increase the number of parts, resulting in restrictions on size and cost.

The present invention has been made to solve such a problem, and an object of the present invention is to automatically switch the damping coefficient without requiring any external energy supply, and to exceed the energy of a normal hydraulic damper. In a damping coefficient switching type hydraulic damper that can always exhibit its absorption capacity, a compact and low-cost hydraulic circuit can be obtained, and it can be effective even from minute vibration levels, and it is also dangerous The present invention is to provide a damping coefficient switching type hydraulic damper capable of exhibiting excellent and stable performance without causing side operation anxiety.

The present invention is a damping coefficient switching type hydraulic damper having a single on-off valve according to claim 1 and a hydraulic circuit with a pilot operating section, but can be combined with the following micro opening / closing function. This damping coefficient switching type hydraulic damper having a micro opening / closing function includes an opening / closing valve in a flow path connecting hydraulic chambers on both sides of a piston reciprocating in a cylinder, and the damping coefficient is switched by opening / closing the opening / closing valve. When the pressure in the hydraulic chamber on one side is rising, the on-off valve maintains a closed state, accumulates pressure in the buffer, and the pressure in the hydraulic chamber starts to decrease. When the pilot piston of the pilot operating part for pilot control is driven by the pressure accumulated in the buffer, the on-off valve opens, and then the on-off valve closes again when the pressure difference between the left and right hydraulic chambers is eliminated In a hydraulic damper that operates like this, when the load is smaller than the crack pressure at which the on-off valve does not operate, the damping coefficient can be controlled only by the opening area of the pilot piston alone As described above, the damping coefficient switching type hydraulic damper is characterized in that a flow path that opens at a pressure lower than the crack pressure of the on-off valve and closes at a pressure higher than the crack pressure is installed on the hydraulic circuit in parallel with the on-off valve. .

For example, as shown in FIG. 1, the opening / closing valve 6 provided in the flow path 5 that connects the hydraulic chambers 4 provided on both sides of the piston 3 that reciprocates in the cylinder is used for the micro open / close function . The present invention is applied to a damping coefficient switching type hydraulic damper that opens and closes according to a pressure change and switches a damping coefficient. In this hydraulic damper, when the buffer 21 is connected to the pilot operating portion 20 of the on-off valve 6 and the piston 3 moves by an external force, the hydraulic oil in the hydraulic chamber 4 is introduced into the buffer 21 to accumulate pressure, and the on-off valve 6 By maintaining the closed state in the pilot operating unit 20, the attenuation coefficient becomes the maximum value Cmax. When the moving direction of the piston 3 is changed at the maximum amplitude point, the pilot operating unit 20 is driven by the pressure accumulated in the buffer 21, whereby the on-off valve 6 is temporarily opened, the load is unloaded, and the damping coefficient is the minimum value Cmin. It becomes. When the piston 3 further moves toward the neutral position, the on-off valve 6 is closed again by the pilot operating unit 20 and the damping coefficient returns to the maximum value Cmax. The other side operates in the same manner as described above, and the above operations are repeated, so that energy such as earthquakes is absorbed well.

In such hydraulic dampers, there is always a crack load on the open / close valve (poppet valve), and in the smaller load range, the essential open / close valve does not open even if the pilot operation unit operates, so wind load, etc. The control performance at the minute vibration level of the is deteriorated. On the other hand, the micro opening / closing function can be controlled only by the opening area of only the pilot piston of the pilot operating section so that the load region lower than the crack pressure at which the opening / closing valve does not operate can be controlled. Therefore, a hydraulic circuit is provided that opens at a pressure lower than the crack pressure of the on-off valve and closes at a pressure higher than the crack pressure. Specifically, as shown in FIG. 1, for example, as shown in FIG. 1, a micro open-close valve 33 having a piston 33 a that opens until the pressure in the hydraulic chamber 4 reaches the crack pressure and closes when the pressure is higher than the crack pressure. The flow path is installed in parallel with the on-off valve 6 so that the hydraulic oil passes through the flow path 32 at a pressure lower than the crack pressure. As a result, even in a load region lower than the crack pressure at which the on-off valve 6 does not operate, oil can flow through the flow path 32, and even at a minute vibration level such as wind vibration, attenuation is the same as in the case of a large external force such as an earthquake. Good seismic control by automatic switching of coefficients.

Note that the basic hydraulic circuit of this micro open / close function is not limited to the left and right independent hydraulic circuit of FIG. 1, but a single open / close valve using the four check valves shown in FIG. 2 and its control hydraulic circuit. It can also be used for a rectifying hydraulic circuit or the like.

Moreover, in this invention, it can combine with the following malfunction elimination function. This damping coefficient switching type hydraulic damper is a hydraulic damper in which an opening / closing valve is provided in a flow path connecting hydraulic chambers on both sides of a piston reciprocating in a cylinder, and the damping coefficient is switched by opening / closing the opening / closing valve. When the pressure in the hydraulic chamber on one side is increasing, the on-off valve is kept closed and the pressure is accumulated in the buffer. When the pressure in the hydraulic chamber starts to decrease, the on-off valve is pilot-controlled. A hydraulic damper that opens and closes when the pilot piston of the pilot operating unit is driven by the pressure accumulated in the buffer, and then the pressure difference between the left and right hydraulic chambers is eliminated. When the hydraulic pressure relationship on both sides of the piston is reversed, the buffer and the low-pressure accumulator are temporarily connected to accumulate in the buffer. It is damping coefficient switching-type hydraulic damper according to claim valve for realizing the functions as the force is eliminated is incorporated.

In the above-described buffer type damping coefficient switching type hydraulic damper, since the hydraulic pressure accumulated in the buffer is used for the driving force of the pilot piston, the opening / closing valve is maintained open when pressure remains in the buffer. There is a risk of malfunction on the dangerous side. On the other hand, the malfunction elimination function connects the buffer pressure and the low-pressure accumulator once in the middle of driving while the pressure on both sides of the piston is reversed, so that the load generated by the damper is 0 (the right and left hydraulic chambers in the cylinder). When the pressure difference in the pressure reaches 0), the pressure once accumulated in the buffer is completely eliminated, so that the pressure remains in the buffer and the open / close valve is kept open. It is. Specifically, for example, as shown in FIG. 2, the buffer 21 and the low-pressure accumulator 7 are connected by a flow path having a switching valve 42. The switching valve 42 is automatically switched by the differential pressure between the left and right hydraulic chambers. When the differential pressure between the left and right hydraulic chambers becomes zero, the switching valve 42 opens at the neutral position, and the hydraulic pressure in the buffer 21 is completely released. As a result, it is possible to reliably prevent a malfunction on the dangerous side that pressure remains in the buffer 21 and the on-off valve 6 continues to be kept open.

Note that the basic hydraulic circuit of this malfunction elimination function is not limited to the single on-off valve using the four check valves shown in FIG. It can also be used for a hydraulic circuit of a mold. Further , the micro opening / closing function and the malfunction elimination function can be combined (see FIG. 4).

According to a first aspect of the present invention, an on-off valve is provided in a flow path connecting hydraulic chambers on both sides of a piston that reciprocates in a cylinder, and the damping coefficient is switched by opening and closing the on-off valve. When the pressure in the hydraulic chamber on one side is rising, the open / close valve is kept closed and the pressure is accumulated in the buffer. When the pressure in the hydraulic chamber starts to drop, the open / close valve is pilot controlled. When the pilot piston of the pilot operating part is driven by the pressure accumulated in the buffer, the on-off valve opens, and then when the pressure difference between the left and right hydraulic chambers is eliminated, the on-off valve is closed again In the hydraulic damper, the cylinder pressure on the high pressure side is introduced into the back pressure chamber of the pilot operating part and the on / off valve, and the port for discharging the back pressure of the on / off valve in the pilot operating part is reduced. By using a switching valve that is connected to the cylinder pressure on the side, it is possible to perform the above opening and closing operations in both directions of the piston with a single on-off valve and pilot operation unit without performing rectification by a check valve. This is a characteristic damping coefficient switching type hydraulic damper.

In the hydraulic circuit of the buffer type damping coefficient switching type hydraulic damper described above, rectification by four check valves is required when control is performed for movement in both directions of the piston with a single on-off valve and pilot operation section (see FIG. 2) In addition, if it is attempted to avoid such rectification by the check valve, separate hydraulic circuits are required for each of the left and right sides (see FIG. 1), both of which increase the number of parts and reduce the size and cost. There are restrictions on the surface. On the other hand, the invention according to claim 1 enables the opening / closing operation of the piston in both the left and right directions by a single opening / closing valve and the pilot operation unit without performing rectification by the four check valves. Specifically, for example, as shown in FIG. 3, a hydraulic circuit of a hydraulic damper provided with a single on-off valve 6 has a higher pressure in the left and right hydraulic chambers 4 with a buffer 21 for pilot operation and an open / close state. A direction switching valve 50 is provided which is connected to the back pressure chamber of the valve 6 and can connect a port for discharging the back pressure of the on-off valve 6 in the pilot operation unit 20 to the lower pressure hydraulic chamber 4. Further, the area ratio (shape) of the on-off valve 6 is set so that the oil flow in both forward and reverse directions can be pilot-operated by back pressure. The direction switching valve 50 is automatically switched by the differential pressure between the left and right hydraulic chambers, and the pilot operating unit 20 is operated by the hydraulic pressure of the higher hydraulic chamber. Thereby, the opening / closing operation | movement with respect to the left-right both directions of a piston is attained by a single on-off valve and pilot operation part, without performing rectification | straightening by four check valves.

In addition, as described in the second and third aspects , the hydraulic circuit by the single on-off valve and the pilot operation unit of the invention according to the first aspect , and / or the minute open / close function and / or the malfunction elimination function are provided. They can also be combined (see FIG. 4).

  In addition, regarding the micro open / close valve, the operation of the micro open / close valve can be interlocked with the operation of the open / close valve. Specifically, for example, as shown in FIG. 5, the piston 6 a of the on-off valve 6 and the spool 60 a of the micro on-off valve 60 are connected. When the opening / closing valve 6 operates at a pressure lower than the crack pressure of the on-off valve 6, the passage flow rate of the spool 60 a is used, and when the on-off valve 6 operates at a pressure higher than the crack pressure, the spool 60 a is automatically operated.

  Further, with respect to the micro open / close valve, the micro open / close valve and the open / close valve can be integrated. Specifically, for example, as shown in FIG. 6, the spool 70 a of the micro open / close valve 70 is incorporated in the piston 6 a of the open / close valve 6. The operation is the same as that of the interlocking type.

Further , the malfunction canceling function and the opening / closing operation function of the single opening / closing valve of the invention according to claim 1 can be realized by one switching valve. Specifically, for example, as shown in FIG. 6, a switching valve 80 having both the function of the direction switching valve 50 and the function of the switching valve 42 in FIG. 2 is installed. On both sides of the spool 80a of the switching valve 80, a portion for opening / closing the opening / closing valve 6 is provided, and a portion for opening / closing the flow path 41 of the malfunction elimination circuit is provided at the neutral position in the center. The spool 80a is moved by the higher pressure in the left and right hydraulic chambers 4, and both side portions of the spool 80a are positioned at the flow path positions. When the pressure difference between the left and right hydraulic chambers 4 becomes zero, the spool 80a moves to the neutral position.

  Since the present invention is configured as described above, the following effects can be obtained.

(1) By using the pressure accumulated in the buffer for the driving force of the on-off valve, the attenuation coefficient can be automatically switched without requiring any external energy supply. Sensors, controllers, solenoid valves, etc. In a damping coefficient switching type hydraulic damper that can always exhibit energy absorption capacity that exceeds that of a normal hydraulic damper without using a power failure power supply and special power supply wiring, the pressure in the left and right hydraulic chambers must be higher. A directional switching valve that can be connected to the pilot operation unit and the back pressure chamber of the on-off valve, and that can connect the port for discharging the back pressure of the on-off valve in the pilot operation unit to the lower pressure hydraulic chamber, By using an on-off valve that can pilot the oil flow in both forward and reverse directions by back pressure, a single on-off valve and In addition, the pilot operation unit can open and close the piston in both the left and right directions, and a damping coefficient switching type hydraulic damper having a compact and low-cost hydraulic circuit can be obtained.

(2) In the buffer type damping coefficient switching type hydraulic damper, a micro on-off valve that opens at a pressure lower than the crack pressure of the on-off valve and closes at a pressure higher than the crack pressure is provided, and its flow path is installed in parallel with the on-off valve. By passing hydraulic oil through the flow path of the micro on-off valve at a pressure lower than the pressure, the damping coefficient can be set using the opening area of the pilot operating part of the on-off valve even in a load region lower than the crack pressure at which the on-off valve does not operate. As in the case of a large external force such as an earthquake, good vibration control by automatic switching of the damping coefficient can be performed even at a minute vibration level such as wind vibration.

(3) In the buffer type damping coefficient switching type hydraulic damper, the buffer pressure and the low pressure accumulator are connected once while the pressure on both sides of the piston is reversed and driven, and the damper generated load is zero (the hydraulic pressure on the left and right sides in the cylinder) When the pressure difference in the chamber reaches 0), the pressure once accumulated in the buffer is completely eliminated, so that the pressure remains in the buffer and the open / close valve continues to be kept open. Is avoided, and malfunctions on the dangerous side are reliably prevented.

  Hereinafter, the present invention will be described based on the illustrated embodiment. This embodiment is an example in which a poppet valve (flow rate adjusting valve) capable of instantaneously shutting off a large flow rate of hydraulic oil at high speed is used as an on-off valve. 1 to 6 show first to sixth embodiments of the present invention. 1 to 6, the main hydraulic circuit of the hydraulic damper is indicated by a solid line, and the hydraulic circuit for controlling the on-off valve is indicated by a dotted line.

(1) First Embodiment This first embodiment is adapted to cope with a minute vibration level such as wind vibration. First, the basic configuration of the hydraulic circuit is as follows. As shown in FIG. 1, the hydraulic damper 1 is provided in a cylinder 2, a double rod type piston 3, hydraulic chambers 4 on both sides of the piston 3, and a flow path 5 that connects both hydraulic chambers, as in the prior art. It consists of two on-off valves 6 and the like. This hydraulic circuit is provided with an accumulator 7 for compensating for a change in volume due to the compression of hydraulic oil or a change in temperature, etc., and hydraulic chambers on the left and right sides via a flow path 10 having a parallel check valve 8 and a throttle 9. The hydraulic oil can be supplied to 4 respectively. In the flow path 5, two check valves 11 are incorporated so that hydraulic oil from one high pressure side hydraulic chamber 4 can flow into the other low pressure side hydraulic chamber 4 through the on-off valve 6. The flow path 5 also incorporates a bi-directional relief valve 12 for releasing excessive pressure in the hydraulic chamber 4.

  The on-off valve 6 and its control hydraulic circuit are independently arranged on the left and right sides, and are connected to the flow paths 5 of the hydraulic chambers 4 on the left and right sides, respectively. The on-off valve 6 on the high pressure side to which the piston 3 has moved and its control hydraulic circuit operate. The hydraulic circuit of the on-off valve 6 is provided with a pilot operation valve 20 as a pilot operation unit that performs opening / closing control of the on-off valve 6 and a buffer 21 that drives the pilot piston 20a of the pilot operation valve 20 with accumulated pressure. Yes.

  The on-off valve 6 has a back surface of the poppet valve 6a and one inlet port of the pilot operation valve 20 connected by an operation flow path 23 having a variable throttle 22, and a front surface and a back surface of the poppet valve 6a. A spring 6b that sets the crack pressure by pressing the poppet valve 6a in the closing direction is provided on the back of the poppet valve 6a. The hydraulic oil in the hydraulic chamber 4 on the high pressure side is supplied to the front and back surfaces of the poppet valve 6a. When the pilot operation valve 20 is closed, the pressure on the front surface of the poppet valve 6a and the back pressure on the poppet valve 6a are Although equal, the projected area on the back pressure side of the poppet valve is larger and is pressed by the spring 6b, so the on-off valve 6 is closed. When the pilot operation valve 20 is opened, the hydraulic oil is discharged to the low pressure side hydraulic chamber 4 through the bypass flow path 24 and the operation flow path 23, so that the on-off valve 6 resists the pressing force of the spring 6b. open.

  The hydraulic oil in the hydraulic chamber 4 on the high pressure side flows into the buffer 21 through the check valve 25 and the throttle 26 and is accumulated. The pressure accumulated in the buffer 21 acts on the front surface of the pilot piston 20a through the flow path 27. Further, the back surface of the pilot piston 20a on the opposite side is connected to the flow path 5 by the flow path 28 so that back pressure acts. Therefore, if the pressure on the front surface of the pilot piston 20a is higher than the back pressure, the pilot operation valve 20 opens. Further, the above-described operation flow path 23 and the flow path 29 from the buffer 21 are connected to the two inlet ports of the pilot operation valve 20. The hydraulic circuit of the buffer 21 is provided with a relief valve 30 that releases excessive pressure.

  In the above configuration, when the piston 3 is in the illustrated neutral position, the pilot operation valve 20 is closed as will be described later, and when the piston 3 moves to the left side in the drawing due to an earthquake or the like, the pressure in the left hydraulic chamber 4 increases. Since the pilot operation valve 20 is closed, the on-off valve 6 is kept closed by the back pressure and the pressing force of the spring 6 b, and pressure is accumulated in the buffer 21. Since the on-off valve 6 is closed, the hydraulic oil in the left hydraulic chamber 4 is confined, so that the damping coefficient becomes the maximum value Cmax.

  When the movement direction of the piston 3 changes at the maximum amplitude point on the left side and starts to move to the right side in the drawing, the pressure in the left hydraulic chamber 4 begins to decrease and the back pressure of the pilot piston 20a also decreases. The pilot piston 20a is driven by the increased pressure, the pilot operation valve 20 is opened, and the hydraulic oil is discharged as described above, whereby the on-off valve 6 is opened. When the on-off valve 6 is opened, the hydraulic oil in the left hydraulic chamber 4 flows into the right hydraulic chamber 4 through the on-off valve 6, so that the load is once removed and the damping coefficient becomes the minimum value Cmin.

  When the piston 3 moves further to the right, the on-off valve 6 is closed. That is, when the pilot operation valve 20 is opened, the hydraulic oil in the buffer 21 is discharged into the left hydraulic chamber 4 through the flow path 29, and the pressure difference between the left and right hydraulic chambers 4 disappears. The pilot operation valve 20 is closed again, and thus the on-off valve 6 is also closed.

  When the piston 3 moves further to the right, the right on-off valve 6 and its control hydraulic circuit operate in the same manner as described above. Even in the right side portion, the pilot operation valve 20 and the on-off valve 6 are initially closed, and a malfunction on the dangerous side is prevented.

  By repeating the above operation on both sides of the cylinder 2, the energy absorption capacity is greatly improved as compared with a hydraulic damper having a constant damping coefficient. In addition, the damping coefficient can be automatically switched only by moving the piston 3 due to an external vibration force such as an earthquake.

  In the hydraulic damper having the above-described configuration, a crack load is always present in the on-off valve 6. Therefore, even if the pilot piston 20a of the pilot operation valve 20 operates in a load region smaller than the crack load, the essential on-off valve 6 Since it does not open, the control performance at a minute vibration level such as wind vibration deteriorates. Therefore, a micro opening / closing circuit 31 that opens at a pressure lower than the crack pressure of the on-off valve 6 and closes at a pressure higher than the crack pressure is provided so that a region lower than the crack pressure at which the on-off valve 6 does not operate can be controlled by the pilot operation valve 20. Since a sufficient opening area cannot be secured by the orifice (throttle) of the flow path 24 installed in parallel with the on-off valve 6 for the purpose of pilot-operating the on-off valve 6, a special micro on-off circuit 31 is provided in parallel with the on-off valve 6. Install.

  Specifically, a flow path 32 capable of supplying hydraulic oil from the hydraulic chamber 4 between the variable throttle 22 of the operation flow path 23 and the pilot operation valve 20 is provided, and a micro opening / closing mechanism is provided in the flow path 32. An on-off valve 33 is provided. A spring to which prestress (compression force) is introduced is provided on the back surface of the piston 33a of the micro open / close valve 33, and the pressure of the hydraulic chamber 4 is introduced to the front surface by the flow path 34 so that the pressing force of the spring is appropriately set. Accordingly, the open state is maintained by the spring until the crack pressure is equivalent, and the spring is closed at a pressure higher than the crack pressure.

  In a load region lower than the crack pressure at which the on-off valve 6 does not operate, it operates as follows. That is, when the piston 3 moves to the left side due to a minute load such as wind vibration, the pilot operation valve 20 is closed as in the case of a large load such as an earthquake described above, so that the on-off valve 6 is also closed. When the piston 3 moves to the right side, the pilot operation valve 20 is opened as in the case of a large load such as the earthquake described above, but the hydraulic oil is discharged through the flow path 32 because the micro open / close valve 33 is open. Is done. As a result, even at a minute vibration level such as wind vibration, it is possible to perform good vibration control by automatic switching of the damping coefficient, as in the case of a large external force such as an earthquake.

  At a pressure higher than the crack pressure at which the on / off valve 6 operates, the micro on / off valve 33 is closed, so the micro on / off circuit 31 does not operate, and the on / off valve 6 is controlled to open / close by the pilot operation valve 20 as usual.

  The first embodiment is applied to a left and right independent hydraulic circuit in which left and right independent on-off valves and control hydraulic circuits are arranged, but a single on-off valve using four check valves and The present invention can also be applied to a rectifying hydraulic circuit (see FIG. 2 described later) using the hydraulic circuit.

(2) Second Embodiment In the second embodiment, the pressure in the buffer is set to 0, and the malfunction on the dangerous side, such as the open / close valve is kept open, can be eliminated. As shown in FIG. 2, the hydraulic circuit of the hydraulic damper 1 is a rectifying hydraulic circuit using four rectifying check valves 13, and only one set of the on-off valve 6 and its control hydraulic circuit need be provided. The other points are almost the same as those of the first embodiment, and the same reference numerals are given and the description is omitted. In this embodiment, the shuttle valve 14 that can select and output inputs in both directions is used for connection between the pilot operation valve 20, the hydraulic circuit of the buffer 21, and the flow path 5.

  In such a hydraulic circuit, a malfunction elimination circuit 40 is provided between the buffer 21 and the low-pressure accumulator 7. Specifically, the buffer 21 and the accumulator 7 are connected by a flow path 41, and a switching valve 42 that opens and closes the flow path is provided in the flow path 41. The hydraulic pressure of the left and right hydraulic chambers 4 is applied to both end faces of the piston 42a of the switching valve 42 through the flow path 43, and is automatically switched by the operation of the hydraulic damper.

  In the configuration as described above, the basic operation is the same as in the first embodiment. When the piston 3 moves to the left side in the drawing, the pressure in the left hydraulic chamber 4 rises and the pilot operation valve 20 is closed. Therefore, the on-off valve 6 is kept closed by the back pressure, and pressure is accumulated in the buffer 21. When the movement direction of the piston 3 changes at the maximum amplitude point on the left side and starts to move to the right side in the drawing, the pressure in the left hydraulic chamber 4 begins to decrease and the back pressure of the pilot piston 20a also decreases. The pilot piston 20a is driven by the increased pressure, the pilot operation valve 20 is opened, and the hydraulic oil is discharged as described above, whereby the on-off valve 6 is opened. The pressure oil in the left hydraulic chamber 4 flows into the right hydraulic chamber 4 through the on-off valve 6.

  In this step, while the pressure in the left hydraulic chamber 4 is higher than the pressure in the right hydraulic chamber 4, the switching valve 42 is closed as shown in the figure, and the pressures in the hydraulic chambers 4 on both sides of the piston 3 are reversed. On the way, when the differential pressure between the left and right hydraulic chambers 4 becomes zero (when the damper generated load becomes zero), the switching valve 42 is opened to the neutral position, and the hydraulic oil remaining in the buffer 21 becomes a low-pressure accumulator. 7 and the pressure accumulated in the buffer 21 is completely eliminated. As a result, it is avoided that pressure remains in the buffer 21 and the on-off valve 6 continues to maintain the open state, and erroneous operation on the dangerous side is reliably prevented. When the piston 3 further moves to the right side and the pressure in the right hydraulic chamber 4 increases, the switching valve 42 is closed, and the next on-off valve 6 and its control hydraulic circuit operate without any trouble.

  The second embodiment is applied to a rectifying hydraulic circuit using four check valves. However, the left and right independent hydraulic circuits (in FIG. 1).

(3) Third Embodiment This third embodiment enables opening and closing operations in both directions of the piston with a single on-off valve and pilot operation section without performing rectification by four check valves. As shown in FIG. 3, only one set of the on-off valve 6 and its control hydraulic circuit is provided, and a direction switching valve 50 is used instead of the four check valves shown in FIG. One on-off valve 6 installed in the hydraulic circuit of the hydraulic damper has an area ratio (shape) set so that the oil flow in both forward and reverse directions can be pilot-operated with back pressure, so the piston 3 moves in both directions. On the other hand, the on-off valve 6 can open and close the flow in two directions.

  The direction switching valve 50 can introduce the higher pressure of the left and right hydraulic chambers 4 into the back pressure chamber of the pilot operation valve 20, and can supply the hydraulic oil in the flow path 23 for operating the on-off valve 6 to the pilot operation valve 20. It is installed so that it can be discharged to the hydraulic chamber 4 with the lower pressure through the. Further, the hydraulic oil in the left and right hydraulic chambers 4 acts on both end faces of the piston 50a of the direction switching valve 50 through the flow passages 51, respectively, and is automatically switched by the operation of the hydraulic damper.

  In the above configuration, the basic operation is the same as in the first and second embodiments. When the piston 3 moves to the left in the drawing, the pressure in the left hydraulic chamber 4 rises, and the pilot operation valve Since the valve 20 is closed, the on-off valve 6 is kept closed by the back pressure, and pressure is accumulated in the buffer 21. When the movement direction of the piston 3 changes at the maximum amplitude point on the left side and starts to move to the right side in the drawing, the pressure in the left hydraulic chamber 4 begins to decrease and the back pressure of the pilot piston 20a also decreases. The pilot piston 20a is driven by the increased pressure, the pilot operation valve 20 is opened, and the hydraulic oil is discharged as described above, whereby the on-off valve 6 is opened. The pressure oil in the left hydraulic chamber 4 flows into the right hydraulic chamber 4 through the on-off valve 6.

  In this step, while the pressure in the left hydraulic chamber 4 is higher than the pressure in the right hydraulic chamber 4, the direction switching valve 50 is switched as shown in the figure, and the left hydraulic chamber 4 controls the on-off valve 6 and its control. The hydraulic circuit is activated. When the piston 3 moves further to the right and the pressure in the right hydraulic chamber 4 increases, the direction switching valve 50 is switched, and the on-off valve 6 and its control hydraulic circuit are operated by the right hydraulic chamber 4.

(4) Fourth Embodiment In the fourth embodiment, the micro opening / closing function of the first embodiment and the malfunction elimination function of the second embodiment are applied to the single hydraulic circuit of the third embodiment. . As shown in FIG. 4, a micro open / close valve 33, a switching valve 42, and a direction switching valve 50 are provided. The operation is a combination of the operations of the respective embodiments, and a description thereof will be omitted.

(5) Fifth Embodiment In the fifth embodiment, the minute opening / closing function is an on-off valve interlocking type. That is, in the first embodiment of FIG. 1, the minute opening / closing function is realized by the piston 33 a independent of the opening / closing valve 6, but as shown in FIG. 5, the minute opening / closing valve 60 interlocked with the operation of the opening / closing valve 6. Is realized. The spool 60a of the micro open / close valve 60 is fixed to the poppet valve 6a of the open / close valve 6 via a connecting rod 61 so that the flow path 62 connecting the operation flow path 23 and the flow path 28 can be opened and closed. ing.

  The hydraulic circuit is the same as the hydraulic circuit in FIG. 4, and the basic operation is the same as in the first embodiment. The operation of the micro opening / closing function is the same as that of the first embodiment, but operates as follows because of the interlocking type. That is, in the load region lower than the crack pressure at which the on-off valve 6 does not operate, the on-off valve 6 is closed and the micro on-off valve 60 is open, and when the pilot operation valve 20 is opened, the flow path 62 and the flow path 23 are opened. Hydraulic fluid is discharged through. When the on-off valve 6 operates at a pressure higher than the crack pressure and the on-off valve 6 is opened, the micro on-off valve 60 is automatically closed.

(6) Sixth Embodiment In the sixth embodiment, the minute opening / closing function is integrated with an opening / closing valve. Furthermore, the function of the direction switching valve of the third embodiment and the function of the switching valve of the second embodiment are realized by one switching valve.

As shown in FIG. 6, the opening / closing function for the minute is formed by integrating the spool 70 a of the opening / closing valve 70 for the opening / closing valve 6 into the poppet valve 6 a of the opening / closing valve 6. . As in the fifth embodiment, the micro open / close valve 70 is configured to open and close a throttled channel 71 that connects the channel 23 and the channel 28 for operation. The operation is the same as in the fifth embodiment, and a description thereof will be omitted.

  Further, a switching valve 80 having both the function of the direction switching valve 50 and the function of the switching valve 42 in FIG. 2 is installed at the position of the direction switching valve 50 in FIG. Specifically, on both sides of the spool 80a of the switching valve 80, the function of the direction switching valve 50, that is, the higher one of the left and right hydraulic chambers 4 is introduced into the back pressure chamber of the pilot operation valve 20, A portion for discharging the hydraulic pressure of the flow path 23 for operating the on-off valve 6 to the lower hydraulic chamber 4 through the pilot operating valve 20 is provided. At the neutral position in the center of the spool 80a, a function of the switching valve 42, that is, a portion for opening and closing the flow path 41 connected to the buffer 21 of the malfunction elimination circuit 40 and the low-pressure accumulator 7 is provided.

  The operation is an operation in which the direction switching valve 50 and the switching valve 42 are combined. The spool 80a of the direction switching valve 80 is moved by the higher pressure in the left and right hydraulic chambers 4, and both sides of the spool 80a flow. Located in the road position. When the pressure difference between the left and right hydraulic chambers 4 becomes zero, the spool 80a moves to the neutral position.

1 is a hydraulic circuit diagram of a first embodiment that can cope with a minute vibration level such as wind vibration of a damping coefficient switching type hydraulic damper according to the present invention; FIG. FIG. 5 is a hydraulic circuit diagram of a second embodiment that can eliminate a malfunction on the dangerous side of the damping coefficient switching type hydraulic damper of the present invention. FIG. 9 is a hydraulic circuit diagram of a third embodiment in which a single on-off valve and a control hydraulic circuit of the damping coefficient switching type hydraulic damper of the present invention can be opened and closed. FIG. 6 is a hydraulic circuit diagram of a fourth embodiment in which the functions of the first embodiment and the second embodiment of the damping coefficient switching type hydraulic damper of the present invention are added to the circuit of the third embodiment. FIG. 10 is a hydraulic circuit diagram of a fifth embodiment in which a minute opening / closing valve of a damping coefficient switching type hydraulic damper according to the present invention is interlocked with the operation of an opening / closing valve. The minute on / off valve of the damping coefficient switching type hydraulic damper of the present invention is integrated with the on / off valve, and the function of the direction switching valve of the single type hydraulic circuit and the function of the switching valve for preventing malfunction is realized by one switching valve. It is a hydraulic circuit figure of 6 embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydraulic cylinder 2 ... Cylinder 3 ... Piston 4 ... Hydraulic chamber 5 ... Flow path 6 ... On-off valve 7 ... Accumulator 8 ... Check valve 9 ... Restriction 10 ... Flow path 11 ... Check valve 12 ... Relief valve 13 ... Rectification check valve 14 ... Shuttle valve 20 ... Pilot operation valve 20a ... Pilot piston 21 ... Buffer 22 ... Variable throttle 23 ... Operation channel 24 ... Bypass channel 25 ... Check valve 26 ... Throttle 27 ... Flow path 28 ... Flow path 29 ... Flow path 30 ... Relief valve 31 ... Micro open / close circuit 32 ... Flow path 33 ... Micro open / close valve 33a ... Piston 40 ... Malfunction elimination circuit 41 ... Flow path 42 ... Switching valve 42a ... Piston 43 ... Flow path 50 ... Direction switching valve 50a ... Piston 51 ... Flow path 60 ... Micro open / close valve (interlocking type)
60a ... Spool 61 ... Connecting rod 62 ... Flow path 70 ... Open / close valve for micro (integral type)
70a ... Spool 71 ... Flow path 80 ... Switching valve 80a ... Spool

Claims (3)

A hydraulic damper provided with an open / close valve in a flow path connecting hydraulic chambers on both sides of a piston reciprocating in a cylinder, and switching a damping coefficient by opening and closing the open / close valve,
While the pressure in the hydraulic chamber on one side is rising, the on-off valve maintains a closed state, accumulates pressure in the buffer, and when the pressure in the hydraulic chamber starts to decrease, a pilot operation unit for pilot-controlling the on-off valve In the hydraulic damper that opens and closes the opening and closing valve by driving the pilot piston of the pressure in the buffer, and then closes the opening and closing valve again when the pressure difference between the left and right hydraulic chambers is resolved,
A switching valve is provided to introduce the cylinder pressure on the high pressure side into the back pressure chamber of the pilot operating section and on-off valve, and to connect the port for discharging the back pressure of the on-off valve in the pilot operating section to the cylinder pressure on the low pressure side. In addition, by using an on-off valve that can pilot-operate the oil flow in both forward and reverse directions by back pressure, the above-mentioned operation is performed with respect to both directions of the piston with a single on-off valve and pilot operating unit without rectification by a check valve A damping coefficient switching type hydraulic damper characterized in that it can be opened and closed. 2. The hydraulic damper according to claim 1, wherein when the load is smaller than the crack pressure at which the on-off valve does not operate , the damper is opened at a pressure lower than the crack pressure of the on-off valve so that the damping coefficient can be controlled only by the opening area of the pilot piston alone. A damping coefficient switching type hydraulic damper characterized in that a flow path that closes at a pressure higher than the crack pressure is provided in parallel with the on-off valve on the hydraulic circuit. 3. The hydraulic damper according to claim 1, wherein when the magnitude relationship between the hydraulic pressures on both sides of the piston is reversed, the pressure accumulated in the buffer is temporarily connected by connecting the buffer and the low-pressure accumulator. 4. A damping coefficient switching type hydraulic damper is incorporated with a valve that realizes a function that eliminates this problem.

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