JP2006220252A - Two-stage pressure absorption piston-type accumulator device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a low-pressure/high-pressure combined accumulator device, and realize stable behavior of a piston for high pressure at the time of transition from a low-pressure stage to a high-pressure stage. <P>SOLUTION: A structure 2 of a high pressure accumulator is formed on one side of a divider member 6, which is a boundary, and a structure 4 of a low pressure accumulator is formed on the other side of the divider member 6. Then oil chambers 11, 12 are demarcated between the pistons 3, 5 of each of the accumulator structures 2, 4 and the divider member 6, and gas chambers 17, 18 are demarcated between the pistons 3, 5 and each of the end covers 9, 10. Then a communicating passage 13 is formed in the divider member 6. The communicating passage 13 connects each of the oil chambers 11, 12 to an exterior hydraulic circuit, and performs supply and discharge of hydraulic oil in accordance with the ascent/descent of the circuit pressure. Then a small-diameter boss part 19 is projected on the oil chamber side of the piston 3 for high pressure, and a fitting recess 20 for the in-and-out movement of the small-diameter boss part 19 is provided to the opening of the communicating passage 13, thus a piston load caused by upsurged pressure oil is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a two-stage pressure absorption type piston accumulator device, and more specifically, a composite accumulator device that allows hydraulic oil having a fluctuating pressure in a hydraulic circuit to be supplied and discharged based on different spring constants at low and high pressures. It is about.

  In a hydraulic circuit that operates by supplying hydraulic oil from a hydraulic pump to an actuator such as a hydraulic motor or a hydraulic cylinder, the circuit pressure rises higher than that in normal operation when a large load is applied to the actuator or the actuator is locked. At this time, the accumulator connected to the hydraulic circuit absorbs the circulating oil in the circuit to relieve the load applied to the actuator, and when the actuator is unlocked, the accumulator discharges the absorbed oil to Make up for the delay. In this way, the accumulator contracts the volume of the gas sealed in the gas chamber in accordance with the pressure of the hydraulic oil entering the oil chamber, thereby achieving a pressure balance and fulfilling the pressure adjusting action of the hydraulic circuit.

  However, in addition to the case where a sudden increase in pressure generated in the hydraulic circuit is absorbed by a single accumulator, the hydraulic pressure is divided by two accumulators in two stages, as in a vehicle suspension mechanism, for example. May try to absorb oil. In other words, when the number of passengers is small, an accumulator with a low spring constant is made to function to exhibit a soft riding comfort, and when the number of passengers is large or the load is heavy, the accumulator that exhibits a high spring constant is operated to increase the support force. ramp up.

  The use of two or more accumulators in this way and using them properly is also described in, for example, Japanese Patent Application Laid-Open No. 2004-360885 and Special Table 2004-522905. 13 and 14 show the movement of the two combination accumulators. As shown in FIG. 14 (a), a high pressure accumulator 51 and a low pressure accumulator 52 are provided, and each of the oil chambers 53, 54 is connected to a main pipe 55 connected to a hydraulic circuit (not shown) via branch pipes 56, 57. Communicated.

  The gas chamber 58 of the high-pressure accumulator 51 is preliminarily filled with, for example, 5 MPa of inert gas and the gas chamber 59 of the low-pressure accumulator 52 is filled with, for example, 2.5 MPa of gas via the charging plugs 60 and 61. In a state before the pipe 55 is connected to the hydraulic circuit, as shown in FIG. 13A, both the pistons 62 and 63 are located at the furthest positions from the respective charging plugs due to the gas pressure.

  If the normal operating pressure at the low pressure stage in the connected hydraulic circuit is, for example, around 3 MPa, the low pressure piston 63 is not shown, but the gas chamber 59 is slightly shrunk to accommodate the introduced oil in the oil chamber 54, thereby obtaining a pressure balance. Displace to the position where If the pressure is temporarily raised to 4.5 MPa in this state, the low pressure piston 63 is displaced by further contracting the gas chamber 59 as shown in FIG. As a result, the oil chamber 54 additionally receives hydraulic oil, and the amount of oil in the hydraulic circuit is reduced by the amount that has entered the oil chamber 54, thereby lowering the circuit pressure. If this pressure increase is temporary and then drops, the piston 63 is pushed back by expansion of the sealed gas, and the additional introduction is returned to the hydraulic circuit.

  Assuming that the pressure of 4.5 MPa just described is not temporary and is due to the load in the example of the suspension mechanism described above, this pressure is the steady operating pressure in the high pressure stage until the load is unloaded. Become. At this time, the piston 62 of the high pressure accumulator 51 having the gas chamber 58 of 5 MPa still remains in the initial position. This state does not change until a pressure of 5 MPa or more is established in the hydraulic circuit, but if the load is heavy and the pressure is 7.5 MPa, the low pressure piston 63 further moves to the left as shown in FIG. At the same time, the high pressure piston 62 is displaced to a position balanced with the pressure.

  Assuming that the hydraulic circuit pressure temporarily rises to 10 MPa while entering the high pressure stage due to the loading of the load, the high pressure piston 62 is displaced to further shrink the gas chamber 58 as shown in FIG. The low pressure piston 63 also contracts the gas chamber 59 until the balance pressure at this time is reached.

In any of the accumulators, the hydraulic oil is received in the oil chamber. However, in the high pressure stage, the amount of increase in the low pressure accumulator 52 is smaller than that in the high pressure accumulator 51. In this example, about 2/3 of the oil absorption at the high pressure stage is taken up by the high pressure accumulator. In general, the movement of the low pressure piston contributes to reducing the pressure increase at the low pressure stage, and the high pressure piston is at the high pressure stage. Contributes to the suppression of pressure increase. In this case, the suspension mechanism exhibits support characteristics based on different spring constants at low pressure and high pressure.
JP-A-2004-360885 Special table 2004-522905

  According to such a combination accumulator, in order to absorb the temporary pressure rise generated in the hydraulic circuit, the pressure oil storage amount is changed in two stages according to the size of the operating hydraulic pressure, and the low pressure stage in the hydraulic circuit In addition, the pressure increase in each of the high pressure stages can be reduced. However, when the number of accumulators is two and more bases are required, the bulkiness of the apparatus becomes excessive. For example, if it is to be adopted in a suspension mechanism, it is indispensable to solve the miniaturization proposition from the viewpoint of mounting on a vehicle.

  By the way, when one hydraulic circuit is a system that takes a low pressure stage and a high pressure stage, a problem occurs at the switching point. It is the pressure oil before and after the high pressure accumulator starts to operate, in the above example, when 4.5 MPa is a steady pressure in the high pressure stage, the scene where the pressure is rapidly increased beyond 5 MPa, We come across a scene that goes back and forth around 5 MPa.

  When the hydraulic circuit pressure rapidly rises to, for example, 7 MPa, the high-pressure accumulator that is hardly loaded is attacked by a rapidly increasing load. The high pressure piston, which has been stopped until now, temporarily prevents the pressure oil from entering, further increasing the pressure of the ingress oil. Due to this, the piston that is forced to move suddenly generates a pressure wave on the gas chamber side. Since the waves reciprocate at a high speed in the gas chamber, the seal mechanism of the piston is intermittently vibrated or receives a pressure shock wave, thereby accelerating the deterioration of the seal strength.

  On the other hand, when the pressure fluctuates little by little at the time of switching between the low pressure stage and the high pressure stage, the piston repeats the movement of returning to the first time when the piston follows it sensitively. When such chattering occurs, the piston strikes the shell cover each time. This damage to the piston body and wear of the piston seal mechanism impairs the reliability of the apparatus and requires frequent maintenance work.

  The present invention has been made in view of the above problems, and its object is to ensure the volume occupied by the entire device in a composite accumulator device including a low-pressure accumulator and a high-pressure accumulator equivalent to the case where there are two accumulators. It is possible to reduce the size of the hydraulic circuit, and to enable gentle acceleration / deceleration of the high-pressure piston at the transition from the low pressure stage to the high pressure stage or vice versa in the hydraulic circuit, and to suppress the sensitive response operation, thereby making the device reliable. It is to provide a two-stage pressure absorption piston type accumulator device that realizes improvement in performance and durability.

  The present invention absorbs a temporary pressure increase generated in the hydraulic circuit, and therefore, the amount of hydraulic pressure can be divided into two stages to change the accommodation amount, thereby reducing the pressure increase in the low pressure stage and the high pressure stage in the hydraulic circuit. It is applied to an accumulator capable of absorbing double pressure. With reference to FIG. 1, the high-pressure accumulator structure 2 is formed on one side and the low-pressure accumulator structure 4 is formed on the other side with reference to FIG. Oil chambers are defined between the pistons 3 and 5 of the accumulator structures 2 and 4 and the partition member 6, and gas chambers 17 and 18 are defined between the pistons 3 and 5 and the end covers 9 and 10 of the accumulator shell. Let The partition member 6 is formed with a communication passage 13 that connects each of the oil chambers 11 and 12 and an external hydraulic circuit, and supplies and discharges hydraulic oil in accordance with the increase and decrease of the circuit pressure. A small-diameter boss portion 19 is formed on the oil chamber side of the high-pressure piston 3 so as to protrude toward the opening of the communication passage 13, and the small-diameter boss portion 19 enters and exits the opening portion of the communication passage 13 facing the high-pressure oil chamber 11. A fitting insertion recess 20 is provided. Thereby, the high pressure piston 3 at the time of switching between the low pressure stage and the high pressure stage can be made to behave smoothly and stably.

  As shown in FIG. 6, the high pressure accumulator structure 2A is formed on the inner side with the inner cylinder member 31 as a boundary, and the low pressure accumulator structure 4A including the ring-shaped piston 5B is formed on the outer side. You can also. The oil chambers 11A and 12A are provided between the one end cover 32 that concentrically holds the inner cylinder member 31 and the outer cylinder member 34 and the pistons 3 and 5B of the accumulator structures 2A and 4A, and the other end cover. Gas chambers 17A and 18A are defined between the piston 33 and the pistons 3 and 5B. One end cover 32 is connected to each of the oil chambers 11 </ b> A and 12 </ b> A and an external hydraulic circuit, and a communication passage 35 is formed to supply and discharge hydraulic oil in accordance with the increase and decrease of the circuit pressure. On the chamber side, a small-diameter boss portion 19 is formed so as to protrude toward the opening of the communication path 35. The opening of the communication passage 35 facing the high-pressure oil chamber 11A is provided with a fitting insertion recess 20 for allowing the small-diameter boss portion 19 to enter and exit, so that the high-pressure piston 3 can be smoothly and smoothly switched between the low-pressure stage and the high-pressure stage. It is designed to be able to behave stably.

  Returning to FIG. 1, the small-diameter boss portion 19 assists the increase / decrease in the amount of hydraulic fluid that moves between the communication passage 13 and the high-pressure oil chamber 11 when entering and exiting the fitting recess 20, and from the low pressure stage to the high pressure stage. It is preferable to form a pressure oil supply / discharge passage 23 for further smoothing the movement of the high-pressure piston 3 in the transition to and from the reverse.

  As shown in FIG. 9, the communication path 36 formed in one end cover 32 may connect only the hydraulic circuit and the low pressure oil chamber 12A. The inner cylinder member 31 is provided with a through hole 37 having a different diameter for allowing the working oil to flow between the low pressure oil chamber 12 </ b> A and the high pressure oil chamber 11 </ b> A in the vicinity of one end cover 32. The through holes 37a, 37b, 37c smoothly increase / decrease the amount of hydraulic oil transferred between the two oil chambers 12A, 11A when the high pressure piston 3A is displaced near one end cover 32, thereby reducing the low pressure stage and the high pressure. In order to stabilize the behavior of the high pressure piston 3 </ b> A at the time of switching to the stage, the hole diameter is given smaller as it approaches the one end cover 32. As shown in FIG. 11, the low pressure and the high pressure of the accumulator formed with the inner cylinder member 31 as a boundary can be reversed.

  For example, as shown in FIG. 3B, an auxiliary path 24 that leads to the high pressure oil chamber 11 is provided, and a check valve 25 that introduces the initial pressure oil when the hydraulic pressure suddenly increases into the auxiliary path 24 to the high pressure oil chamber 11. You may make it interpose.

  According to the present invention, two accumulators are arranged with the partition member as a boundary, and both the low pressure accumulator structure and the high pressure accumulator structure are arranged on the partition member side, and these oil chambers are connected to an external hydraulic circuit. Since the communication passage is formed in the partition member, the amount of hydraulic pressure is divided into two stages, the accommodation amount is changed, and the pressure increase in the low pressure stage and the high pressure stage in the hydraulic circuit is reduced by accumulators having different spring constants. be able to. Then, the partition member is shared as the shell cover of the two accumulators, so that the device as the composite accumulator can be shortened and the vehicle can be downsized for the suspension mechanism.

  Since it has a small-diameter boss formed to protrude to the oil chamber side of the high-pressure piston and a fitting insertion recess provided in the opening of the communication passage facing the high-pressure oil chamber, the low-pressure stage and the high-pressure stage in the hydraulic circuit Occurrence of unstable piston behavior at the time of switching can be avoided. Suppressing high-speed pistons during sitting and leaving, and suppressing sensitive behavior based on slight pressure changes, increase the reliability and durability of not only the piston but also the entire device.

  A high pressure accumulator structure is formed on the inner side with the inner cylinder member as a boundary, and a low pressure accumulator structure with a ring-shaped piston is formed on the outer side, and an oil chamber is formed between each accumulator piston. Even if a communication passage is formed in the end cover and a fitting insertion recess through which the small-diameter boss part enters and exits is provided, the excessively reactive behavior of the high-pressure piston at the switching point between the high-pressure stage and the low-pressure stage Suppressing and smooth and soft seating are promoted, and the same effect as described above is exhibited. In addition, since the accumulator has a double arrangement, the entire apparatus is rapidly shortened.

  If a pressure oil supply / discharge path is formed in the small-diameter boss portion, the high-pressure oil chamber and the insertion concave portion when the small-diameter boss portion comes out of the insertion concave portion and when fitting into the insertion concave portion, that is, By gradually increasing or decreasing the amount of hydraulic oil that moves between the communication passages, an acceleration / deceleration that does not impose a burden on the piston is given, and the transition between the low pressure stage and the high pressure stage is made smoother.

  Only the low pressure oil chamber is directly connected to the hydraulic circuit, and the inner cylinder member is provided with a plurality of through holes through which hydraulic oil flows between the low pressure oil chamber and the high pressure oil chamber. If the diameter of the high pressure piston is located on the end cover side, the amount of hydraulic oil transferred between the oil chambers is smoothly increased or decreased between the low pressure stage and the high pressure stage. Smooth transitions in This is the same even if the low pressure accumulator is disposed on the inner side and the high pressure is disposed on the outer side with the inner cylinder member as a boundary.

  If a check valve is interposed in the auxiliary passage leading to the high pressure oil chamber, the initial pressure oil at the time when the circuit pressure suddenly rises can be quickly introduced into the high pressure oil chamber. The sudden change in pressure of the oil chamber when the small-diameter boss portion comes out of the insertion recess is reduced by oil feeding from the check valve, and the occurrence of impact and noise generated in the oil chamber can be suppressed.

  On the other hand, since the check valve prevents the flow of oil from going out from the oil chamber to the communication path, the amount of hydraulic oil coming out of the oil chamber due to a sudden drop in circuit pressure is suppressed. As a result, the occurrence of the oil squeezing flow when the small-diameter boss part enters the insertion recess is not impaired, and the soft seating of the piston is promoted so that the gas seal mechanism is not released when it stops suddenly. I can leave. By the way, even if there is no small-diameter boss, the check valve increases the amount of oil supplied to the high-pressure oil chamber at the beginning of sudden pressure increase, assisting the initial operation of the high-pressure piston, and shutting off the auxiliary path during pressure reduction To alleviate sudden piston deceleration at the end of oil drain.

  Hereinafter, a two-stage pressure absorption type piston accumulator device according to the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 1 shows an example of a composite accumulator device 1 that can supply and discharge hydraulic oil whose pressure fluctuates in a hydraulic circuit based on different spring constants at low pressure and high pressure, and a piston of a high pressure accumulator structure 2. 3 and the piston 5 of the low-pressure accumulator structure 4 are opposed to each other. Such accumulators not only make it possible to reduce the size for in-vehicle use, etc., but also suppress undesired behavior at the time of pressure stage switching that tends to occur in composite accumulator devices, improving the reliability of the device. In this way, it can be made highly durable.

  Referring to FIG. 1 (a), a high-pressure accumulator structure 2 is formed on the left and a low-pressure accumulator structure 4 is formed on the right. Each accumulator shell is arranged on a partition member 6 disposed in the middle portion. 7 and 8 are integrated by screwing. Gas chamber side shell covers (end cover) 9 and 10 are screwed to the left and right ends of the figure, and the pistons 3 and 5 are displaced in a space sandwiching the partition member 6. The partition member 6 functions as an oil chamber side shell cover as viewed from the high pressure accumulator and from the low pressure accumulator and also serves as a base for connection to a hydraulic circuit (not shown).

  Since the oil chambers 11 and 12 of the respective accumulators are formed on the left and right sides of the partition member 6, the partition member 6 is connected to each oil chamber and an external hydraulic circuit to increase and decrease the circuit pressure. Accordingly, a communication passage 13 for supplying and discharging hydraulic oil is formed. The oil passage is composed of a high-pressure passage 13A and a low-pressure passage 13B extending in the axial direction, and a main passage 13C extending in the radial direction ending with a plug hole 14 connecting the piping of the hydraulic circuit. Each shell cover 9, 10 located opposite to the partition member 6 has a gas charging plug 15, 16 through which a gas chamber 17 between the pistons 3, 5 and the shell cover 9, 10 is provided. , 18 is stored with the initial pressure.

  By the way, the high-pressure piston 3 is provided with a small-diameter boss portion 19 on the oil chamber side so as to protrude toward the opening of the high-pressure passage 13A. On the other hand, an insertion insertion recess 20 for allowing the small-diameter boss portion 19 to enter and exit is formed in the opening portion of the passage 13A facing the high pressure oil chamber 11. As shown in FIG. 2B, the recess 20 is provided with an inner diameter so that the small-diameter boss portion 19 is fitted to such a degree that a slight gap is left, and a large portion of the small-diameter boss portion 19 is removed from the insertion insertion recess 20. Through a slight gap, the oil chamber 11 (the chamber width is only represented by a line because it does not contain oil) is gradually increased, and the small-diameter boss portion 19 is fitted during reverse oil discharge. Until it fits in the insertion recess 20, it acts so as to suppress sudden oil leakage.

  A stop seat surface 21 that abuts the outer edge 3a of the oil chamber side of the high pressure piston 3 is formed at the peripheral edge of the insertion recess 20, and when the pressure from the hydraulic circuit is lower than the sealed pressure of the gas chamber 17 In principle, an oil reservoir is not generated in the high pressure oil chamber 11. If the insertion recess 20 is shallow and the tip of the small-diameter boss portion 19 touches the bottom (not shown), the residual oil in the oil chamber 11 generates a negative pressure when the piston is displaced by the next arrival of high-pressure oil, This is because the smoothness at the beginning of the piston movement is hindered.

  The operation as a two-stage pressure type accumulator will be specifically described below. FIG. 2A shows a state in which predetermined pressures are sealed in the gas chambers 17 and 18, respectively. If this is connected to a hydraulic circuit and the circuit is in a normal operating pressure state, for example, 3 MPa, the low-pressure piston 5 compresses the gas sealed at 2.5 MPa to transfer the hydraulic oil to the low-pressure oil chamber 12. Trying to contain. Now, when the operating oil pressure rises to 4.5 MPa, the piston 5 strokes about a half stroke as shown in (b).

  If the pressure continues to rise, for example, 6 MPa, the pressure acts on the front surface of the small-diameter boss portion 19 and a slight gap between the small-diameter boss portion 19 and the insertion insertion recess 20 as shown in FIG. The hydraulic oil enters the oil chamber 11 as shown by an arrow 22 through the gap. Since the high pressure oil does not suddenly enter the oil chamber, the piston 3 gradually starts to move backward.

  When the small-diameter boss portion 19 is completely pulled out of the insertion recess 20 as shown in FIG. 1B, the high-pressure piston 3 balances the pressure acting on both sides thereof as shown in FIG. Retreat until. In this way, the movement of the piston 3 is suppressed from acting sensitively in response to the action of the high-pressure oil, and gas sealing due to a sudden displacement of the piston or an increase in sealing burden due to the high-pressure oil blocking action by the piston. Such a problem is solved.

  When hydraulic oil is pulled from the high pressure accumulator 2 which has been 6 MPa due to temporary pressure increase, the flow returns to (a) through (b) in FIG. When the small-diameter boss portion 19 starts to be inserted into the insertion insertion recess 20, the rapid oil removal from the oil chamber 11 is suppressed, and the piston 3 is softly seated without impact on the partition member 6. Thereafter, if the hydraulic circuit fluctuates below 5 MPa, the pressure oil supply / discharge operation by the low pressure accumulator 4 is performed, and if the hydraulic circuit fluctuates over 5 MPa, the pressure oil supply / discharge operation including the high pressure accumulator 2 is performed.

  By the way, even if there is a slight increase in pressure such that the switching from the low pressure stage to the high pressure stage or vice versa is repeated, the above-described low acceleration of the seating / separation of the high pressure piston is performed by the high pressure piston 3. Suppress sensitive behavior. Therefore, even if the high pressure piston 3 is at the home position as shown in FIG. 2B, chattering is reduced as much as possible. For this reason, there is a problem when the hydraulic oil capacity is changed by dividing the size of the hydraulic pressure into two stages, and the pressure increase in the low pressure stage and the high pressure stage in the hydraulic circuit is reduced by accumulators with different spring constants. Solved. Since the partition member 6 also serves as a shell cover for the two accumulators, the apparatus can be shortened to meet the demand for miniaturization for a vehicle suspension mechanism or the like.

  Needless to say, it is possible to avoid a skit at the time of entry into the fitting insertion recess 20 by rounding the peripheral tip of the small-diameter boss 19 (not shown), but it can be seen from any of FIGS. In addition, by making the portion into a truncated conical surface, an annular path 23 having a wedge-shaped cross section is formed between the inner wall of the fitting insertion recess 20. This annular path not only eliminates the above-described skirmish, but also is in the state shown in FIG. 1A, that is, immediately before the small-diameter boss portion 19 is completely removed from the fitting recess 20, the hydraulic oil chamber 11. It gradually increases the amount of inflow into the cylinder and acts to increase the acceleration of the piston smoothly. At the time of reverse movement, the transition from the oil chamber 11 to the fitting recess 20 is gradually regulated to smoothly change the deceleration of the piston.

  3B, the partition member 6 is provided with an auxiliary passage 24 that directly leads from the middle of the communication passage 13 to the high pressure oil chamber 11, and a check valve 25 that allows only a flow in the direction of the oil chamber is provided in the partition member 6. This is an example. According to this, when entering the high pressure stage, the pressure oil in the communication passage 13 is guided to the oil chamber 11 through the check valve 25. If the shallow circumferential groove 3b is also formed on the oil chamber side of the piston 3, the pressure is easily applied to the piston. In this way, if the initial pressure oil at the time of sudden hydraulic pressure rise is forwarded to the high pressure oil chamber 11 via the auxiliary passage 24, the small-diameter boss portion 19 is moved from the insertion recess 20 for a short time because the pressure increase width is large. Even if it comes out soon, a large sudden change in pressure in the oil chamber 11 is suppressed, and the occurrence of shock and abnormal noise due to the small diameter boss portion coming off is prevented.

  On the contrary, when the high pressure oil is suddenly returned from the high pressure oil chamber 11 to the hydraulic circuit, the check valve 25 prevents a flow from going out from the oil chamber 11 to the communication path 13 via the auxiliary path 24. This suppresses an increase in the hydraulic oil removal speed and the amount of drained oil when the piston 3 returns due to a sudden drop in the hydraulic circuit, and the occurrence of oil throttle flow when the small-diameter boss portion 19 enters the insertion insertion recess 20. The soft return of the high pressure piston 3 is guaranteed without damage. There is no possibility that the gas sealing mechanism is lost due to the sudden stop of the piston, that is, the gas does not enter the oil chamber.

  In each of the above examples, the shells 7 and 8 for the respective accumulator structures are screwed to the partition member 6. However, as shown in FIG. 4A, the partition member 6A is attached to one cylindrical shell 8A. It is also possible to form two accumulator structures 2 and 4 at the boundary. Further, as shown in (b) or the like, a small-diameter boss portion 19A may be formed on the low-pressure piston 5A. Although the action of the small-diameter boss part in the low-pressure accumulator is not particularly expected, even if the shell is reversely mounted due to the appearance of the shell being very similar to the left and right, the positionally convenient one can function as the high-pressure accumulator. .

  In this example, a recessed path 26 is provided instead of the annular path 23 described above. This is located in the tip peripheral surface portion of the small-diameter boss portion 19 and extends in the axial direction, and is an appropriate number of notches 26a whose width and depth increase as the tip is applied to the piston 3, For example, the groove 26b may have a constant width and depth as depicted on the piston 5A. In any case, the same function as that of the circular path 23 is achieved.

  FIG. 5A is an example in which a guide hole 27 that reaches the outer peripheral surface through the inside of the small-diameter boss portion 19 is provided. As shown in FIG. 5B, a desired size is provided at the outlet or inlet of the guide hole 27A. Plugs 28A and 28B having small holes 28a can be attached. By selecting the diameter of the small hole 28a, the connection characteristic at the time of switching of the pressure stage can be changed, and the standardization of the piston is facilitated. These pressure oil supply / discharge passages such as the annular passage 23, the recessed passage 26, and the guide hole passage 27 move between the high pressure oil chamber and the communication passage when the small-diameter boss portion enters or exits the insertion recess. The transition between the low-pressure stage and the high-pressure stage is made even smoother, such as by gradually increasing or decreasing the amount of hydraulic oil to be applied to give an acceleration / deceleration that does not impose a burden on the piston.

  In the examples of FIGS. 6, 7A and 7B, etc., the accumulator shell is a double cylinder. This is because a small-diameter boss 19 and a fitting recess 20 are provided (see FIG. 6), a check valve 25 (see FIG. 7A), a pressure oil supply / discharge passage 23 (see FIG. 6), 26. (Refer to (b) of FIG. 7), 27 (refer to (a) of FIG. 8), plug 28 (refer to (b) of FIG. 8), etc. Although there is no difference as described below, the double cylinder is used.

  First, as shown in FIG. 6, the high pressure accumulator structure 2A is formed on the inner side of the inner cylindrical member 31, and the low pressure accumulator structure 4A is formed on the outer side. The latter piston 5B is different from the former piston 3 in the ring. It has become a shape. The end covers 32 and 33 of the shell hold the inner cylinder member 31 and the outer cylinder member 34 concentrically, and one end cover 32 defines the oil chambers 11A and 12A together with the pistons 3 and 5B. The other end cover 33 defines gas chambers 17A and 18A. The former is provided with a communication passage 35, and the latter is provided with charging plugs 15A, 16A filled with gas.

  Also in such a double cylinder accumulator device 1A, the excessively reactive behavior of the high-pressure piston 3 at the time of switching between the high-pressure stage and the low-pressure stage is suppressed, and the displacement behavior and the soft seating operation due to the smooth acceleration / deceleration change. Is encouraged. In terms of size, the shortening of the entire device due to the double arrangement is natural, but it is natural. Needless to say, even if the pressure oil storage capacity of two accumulators is secured, the increase in the bulkiness in the diameter direction can be suppressed to a surprisingly small value.

  FIG. 9 does not provide the small-diameter boss portion 19 and the fitting insertion recess 20 described above, but provides a plurality of small communication holes in the inner cylinder member 31, thereby smoothly increasing or decreasing the amount of hydraulic oil that moves between the two oil chambers. Thus, the piston behavior at the time of switching between the low pressure stage and the high pressure stage can be stabilized. Specifically, the communication path 36 formed in the one end cover 32 connects only the external hydraulic circuit and the low pressure oil chamber 12A as shown in FIG. The oil is guided to the high pressure oil chamber via the low pressure oil chamber.

  As shown in FIG. 9B, the inner cylinder member 31 has through holes 37 having different diameters through which hydraulic oil flows between the low pressure oil chamber 12A and the high pressure oil chamber 11A, as one end cover. 32 is provided in the vicinity. When the high pressure piston 3 </ b> A is displaced near one end cover, these through holes have smaller hole diameters as they approach the end cover 32 in order to smoothly increase or decrease the amount of hydraulic oil transferred between the two oil chambers. Is given to be. Note that the low-pressure piston 5C may have a rectangular outline in one section of the ring portion as shown in FIG. 11 described later, but in this example, a space 5c is secured in the inner part on the low-pressure oil chamber side, Consideration is given so that the inner peripheral sealing mechanism 38 of the low-pressure piston does not interfere with the through-hole array.

  The pressure oil from the communication path 36 is buffered by a low pressure accumulator structure, but when entering the high pressure stage, the pressure oil enters the high pressure oil chamber 11A through the low pressure oil chamber 12A. The high pressure piston 3A is in the home position as shown in FIG. 9A, but a slight amount of pressurized oil is introduced into the high pressure oil chamber from the first through hole 37a. When the piston starts to be displaced, the second through hole 37b shown in (b) is opened, and the amount of introduced oil increases. Further, if the third through hole 37c is opened, the pressure oil entering from the three through holes is received. Since the opening area of the through-hole increases in three stages, the amount of inflow oil gradually increases. In this example, it can be seen that the high pressure piston 3 </ b> A also functions as a “sliding spool” that opens and closes the through hole 37.

  In such an accumulator device, since there is no small-diameter boss portion, there is no pressure oil supply / discharge passage formed in the accumulator device, but as described above, it is scattered in the circumferential direction but arranged in rows in the axial direction. The hole array realizes a similar action, and the behavior of the high-pressure piston is almost the same. Incidentally, as shown in FIG. 10 (a), the check valve 25 can be interposed in the auxiliary passage 24 that communicates with the communication passage 36 and the high pressure oil chamber 11A. There is no difference from what has been described. (B) is an example in which the stroke end of the high-pressure piston 3B is moved to the end cover 32 beyond the first through hole 37a. Although there is no particular difference in operation, it teaches different variations of the piston.

  FIG. 11 shows an example in which the accumulator formed with the inner cylinder member 31 as a boundary is reversed for low pressure and high pressure. The communication passage 39 is straight, but is not different from the previous example in that it communicates only with the low pressure oil chamber 12B. It is the same idea as FIG. 9 that the outer peripheral seal mechanism 40 of the low pressure piston 5D is deformed so as not to rub against the through hole 37. While the high pressure piston 3C is displaced from (a) to (b), the through holes 37a, 37b, and 37c are opened one after another to increase the flow rate, which is the same as described above.

  FIG. 12 is an example in which a check valve 25 is provided. The shape of the auxiliary path 24A is slightly different from that of FIG. 7 and the like, but is functionally the same in that it flows into the high pressure oil chamber 11B. Therefore, the check valve valve 25A can be interposed in the auxiliary passage 24B exiting from the low pressure oil chamber 12B. Since the check valve in these examples exhibits the function of promoting the introduction of pressure oil and the function of suppressing the derivation, it contributes to the acceleration / deceleration adjustment of the high pressure piston.

  As can be seen from the above description, the present invention allows the low pressure accumulator and the high pressure accumulator to accommodate the size of the hydraulic pressure in two stages, and the temporary pressure increase in the low pressure stage and the high pressure stage in the hydraulic circuit is different. It can be buffered by a constant accumulator. In addition, although the length and bulk of the device as a composite accumulator can be reduced and the size can be reduced, the unstable behavior of the piston that is encountered due to the integration is eliminated, and the composite accumulator is extremely practical. It can be.

1 is a cross-sectional view of a two-stage pressure absorption piston accumulator device according to the present invention. The operation | movement figure which shows the state before a hydraulic circuit connection, and the pressure oil accommodation state in a low pressure stage. The operation | movement figure and check valve interposition figure which show the pressure oil accommodation state in a high pressure stage. Sectional drawing of a different example. Furthermore, sectional drawing of a different example. Sectional drawing of the composite accumulator apparatus by a double shell. A modification of the double shell accumulator. Different modifications of the double shell accumulator. Sectional drawing of the double shell type | mold accumulator which made the inner cylinder member provide the through-hole. The modification of a composite accumulator provided with a through-hole. Sectional drawing which has arrange | positioned the accumulator structure for high voltage | pressure outside the inner cylinder member. The modification which provided the accumulator structure for high voltage | pressure outside the inner cylinder member. The block diagram of the accumulator apparatus which can absorb double pressure as a prior art. The operation explanatory view which entered the high pressure stage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A ... Composite accumulator device, 2, 2A ... High pressure accumulator structure, 3, 3A, 3B, 3C ... High pressure piston, 4, 4A ... Low pressure accumulator structure, 5, 5A, 5B, 5C, 5D ... Low pressure Piston, 6, 6A ... partition member, 9, 10 ... gas chamber side shell cover, 11, 11A, 11B ... high pressure oil chamber, 12, 12A, 12B ... low pressure oil chamber, 13 ... communication path, 17, 17A ... Gas chamber for high pressure, 18, 18A ... Gas chamber for low pressure, 19, 19A ... Small diameter boss, 20 ... Insertion recess, 23 ... Annular path (pressure oil supply / discharge path), 24, 24A, 24B ... Auxiliary path, 25 , 25A ... check valve, 26 ... recessed path (pressure oil supply / discharge path), 27, 27A ... guide hole path (pressure oil supply / discharge path), 31 ... inner cylinder member, 32, 33 ... shell cover (end cover) , 34 ... outer cylinder member, 35, 36 ... communication path, 3 ... through hole, 37a ... first through hole, 37b ... second through hole, 37c ... third hole, 39 ... communicating passage.

Claims (6)

In order to absorb the temporary increase in pressure generated in the hydraulic circuit, the capacity of the hydraulic circuit is divided into two stages and the capacity is changed to reduce the pressure increase in each of the low pressure and high pressure stages of the hydraulic circuit. In an accumulator capable of absorbing pressure,
A high pressure accumulator structure is formed on one side of the partition member, and a low pressure accumulator structure is formed on the other side.
An oil chamber is defined between the piston of each accumulator structure and the partition member, and a gas chamber is defined between the piston and each end cover of the accumulator shell,
The partition member is connected to each oil chamber and an external hydraulic circuit, and is formed with a communication path for supplying and discharging hydraulic oil according to the increase and decrease of the circuit pressure,
On the oil chamber side of the high-pressure piston, a small-diameter boss is formed protruding toward the opening of the communication path,
The opening of the communication passage that faces the high-pressure oil chamber is provided with a fitting insertion recess that allows the small-diameter boss portion to enter and exit, so that the high-pressure piston behaves smoothly and stably when switching between the low-pressure stage and the high-pressure stage. A two-stage pressure-absorbing piston type accumulator device characterized in that In order to absorb the temporary increase in pressure generated in the hydraulic circuit, the capacity of the hydraulic circuit is divided into two stages and the capacity is changed to reduce the pressure increase in each of the low pressure and high pressure stages of the hydraulic circuit. In an accumulator capable of absorbing pressure,
A high pressure accumulator structure is formed on the inner side with the inner cylinder member as a boundary, and a low pressure accumulator structure having a ring-shaped piston is formed on the outer side,
An oil chamber is defined between one end cover that concentrically holds the inner cylinder member and the outer cylinder member and the piston of each accumulator structure, and a gas chamber is defined between the other end cover and the piston,
One end cover is connected to each oil chamber and an external hydraulic circuit, and a communication passage is formed to supply and discharge hydraulic oil according to the increase and decrease of the circuit pressure.
On the oil chamber side of the high-pressure piston, a small-diameter boss is formed protruding toward the opening of the communication path,
The opening of the communication passage that faces the high-pressure oil chamber is provided with a fitting insertion recess that allows the small-diameter boss portion to enter and exit, so that the high-pressure piston behaves smoothly and stably when switching between the low-pressure stage and the high-pressure stage. A two-stage pressure-absorbing piston type accumulator device characterized in that   The small-diameter boss portion assists increase / decrease in the amount of hydraulic fluid that moves between the communication passage and the high-pressure oil chamber when entering / exiting the insertion recess, and in the transition from the low pressure stage to the high pressure stage and vice versa. 3. The two-stage pressure absorption piston type accumulator device according to claim 1, wherein a pressure oil supply / discharge passage for further smoothing the movement of the high pressure piston is formed. In order to absorb the temporary increase in pressure generated in the hydraulic circuit, the capacity of the hydraulic circuit is divided into two stages and the capacity is changed to reduce the pressure increase in each of the low pressure and high pressure stages of the hydraulic circuit. In an accumulator capable of absorbing pressure,
A high pressure accumulator structure is formed on the inner side with the inner cylinder member as a boundary, and a low pressure accumulator structure having a ring-shaped piston is formed on the outer side,
An oil chamber is defined between one end cover that holds the inner cylinder member and the outer cylinder member concentrically and the piston of each accumulator, and a gas chamber is defined between the other end cover and the piston,
One end cover is connected to a low pressure oil chamber and an external hydraulic circuit, and a communication passage is formed to supply and discharge hydraulic oil according to the increase and decrease of the circuit pressure.
The inner cylinder member is provided with a through hole having a different diameter for allowing the working oil to flow between the low pressure oil chamber and the high pressure oil chamber in the vicinity of the one end cover,
When the high-pressure piston is displaced near one end cover, the through hole smoothly increases or decreases the amount of hydraulic oil that moves between the two oil chambers, and the high-pressure piston is switched between the low-pressure stage and the high-pressure stage. A two-stage pressure-absorbing piston type accumulator device characterized in that the hole diameter is given smaller as it approaches the one end cover so that the behavior becomes stable.   5. The two-stage pressure absorption piston type accumulator device according to claim 4, wherein the low-pressure and high-pressure accumulators formed with the inner cylinder member as a boundary are reversed. 6. An auxiliary passage communicating with the high pressure oil chamber is provided, and a check valve for introducing the initial pressure oil when the hydraulic pressure suddenly increases into the auxiliary passage is interposed in the auxiliary passage. A two-stage pressure absorption type piston accumulator device according to any one of the preceding claims.