JP2019183876A - Pressure accumulation structure - Google Patents

Abstract

To provide a pressure accumulation structure capable of quickly increasing oil pressure to fastening pressure of a friction fastening element in oil supply, and moderately decreasing oil pressure across the fastening pressure of the friction fastening element in oil discharge.SOLUTION: A pressure accumulation structure 100 comprises: an accumulator 4 that includes the fastening pressure of a friction fastening element 2 within a single operating pressure range, and in which a pressure accumulating chamber 43 is partitioned; first and second branch passages 5 and 6 branched from the middle of an oil passage 3, and connected to a pressure accumulation chamber 43; a first check valve 7 that is arranged in the first branch passage 5, and opens when the oil pressure of the frictional engagement element 2 becomes equal to or higher than a predetermined pressure, to allow only the flow of oil from the oil passage 3 toward the pressure accumulation chamber 43; and a second check valve 8 that is arranged in the second branch passage 6, and allows only the flow of oil from the pressure accumulation chamber 43 toward the oil passage 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure accumulating structure including an accumulator.

  The accumulator is a device that stores high-pressure fluid, and in the field of automatic transmission, as disclosed in Patent Document 1, by connecting the accumulator to an oil passage that supplies hydraulic pressure to frictional engagement elements such as a clutch and a brake, Adjustment of oil supply / discharge characteristics is performed.

  For example, an accumulator is connected to an oil passage that is connected to a frictional engagement element that is engaged at the time of starting, and the operating pressure range of the accumulator is set to include the engagement pressure of the frictional engagement element. With this configuration, when oil is discharged from the frictional engagement element and the frictional engagement element is released, the hydraulic pressure can be gradually reduced within the accumulator operating pressure range, that is, before and after the clutch engagement pressure. The shock due to the sudden release of the fastening element and the release of the torsion of the drive system parts can be suppressed.

JP 2011-47418 A

  However, in the above configuration, although the shock at the time of releasing the frictional engagement element can be suppressed, the hydraulic pressure gradually increases before and after the engagement pressure of the frictional engagement element even at the time of engagement of the frictional engagement element, so that the engagement of the frictional engagement element is delayed. Cause. The fastening delay of the frictional fastening element that is fastened at the time of start leads to a decrease in start response, which is not preferable.

  The present invention has been made in view of such a technical problem. When oil is supplied, the hydraulic pressure is quickly increased to the fastening pressure of the frictional engagement element, and when oil is discharged, the hydraulic pressure is gradually increased across the fastening pressure of the frictional engagement element. An object is to provide a pressure accumulation structure that can be lowered.

  According to an aspect of the present invention, there is provided a pressure accumulating structure provided in an oil passage connecting an oil pressure switching valve and a friction engagement element in an automatic transmission, wherein the engagement pressure of the friction engagement element is set within a single operating pressure range. An accumulator in which a pressure accumulating chamber is partitioned, a first and second branch path branching from the middle of the oil path and connected to the pressure accumulating chamber, and the friction fastening element disposed in the first branch path A first check valve that opens when the hydraulic pressure of the oil reaches a predetermined pressure or higher and permits only the flow of oil from the oil passage toward the pressure accumulation chamber, and is disposed in the second branch passage, from the pressure accumulation chamber to the oil passage And a second check valve that allows only the flow of oil toward the pressure accumulation structure.

  According to the above aspect, when oil is supplied, since the accumulator does not accumulate pressure until the first check valve is opened, the friction engagement element is formed by accumulating the accumulator before the friction engagement element is engaged. Thus, the start delay of the vehicle can be improved. When oil is discharged, the hydraulic pressure is gradually lowered across the fastening pressure of the frictional engagement element, so that a shock due to abrupt release of the frictional engagement element can be suppressed.

It is a schematic block diagram of the pressure accumulation structure which concerns on embodiment of this invention. It is the figure which showed the time change of the oil_pressure | hydraulic at the time of supplying oil to the friction engagement element of a releasing state. It is the figure which showed the flow of the oil at the time of oil supply and before a 1st check valve opening. It is the figure which showed the flow of the oil at the time of oil supply and after a 1st check valve opening. It is the figure which showed the comparative example of the pressure accumulation structure. It is the figure which showed the time change of the hydraulic pressure at the time of discharging | emitting oil from the friction engagement element of a fastening state. It is the figure which showed the flow of the oil at the time of oil discharge and after a 2nd check valve opening.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the specific numerical values used in the following description are reference values for facilitating understanding of the invention, and the technical scope of the present invention is not limited to these specific numerical values.

  FIG. 1 shows a schematic configuration of a pressure accumulating structure 100 according to an embodiment of the present invention. In the automatic transmission, the pressure accumulating structure 100 includes a hydraulic switching valve 1 (manual valve) for switching the oil supply / discharge state from the hydraulic pressure source to the friction engagement element 2 and the friction engagement elements 2 such as a clutch and a brake that are engaged when starting. Is used for adjusting the oil supply / discharge characteristics of the frictional engagement element 2. In this example, the hydraulic pressure switching valve 1 is a manual valve that is linked to the driver's shift lever operation, but may be operated by an electric actuator.

  The fastening pressure of the friction fastening element 2 is 0.2 MPa in this example. When the hydraulic pressure of the frictional engagement element 2 (the hydraulic pressure of the oil supplied to the oil chamber of the piston that displaces the friction material) exceeds the engagement pressure, the frictional engagement element 2 is engaged, and when the oil pressure falls below this, the friction engagement element 2 is released. . In addition, since the hydraulic pressure of the frictional engagement element 2 is equal to the hydraulic pressure of the oil passage 3, hereinafter, the terminology will be unified with the hydraulic pressure of the frictional engagement element 2.

  The accumulator structure 100 is configured with the accumulator 4 as the center, and in addition to the accumulator 4, the first branch path 5 branched from the first position 31 of the oil path 3 and connected to the accumulator 4, and the first position 31 of the oil path 3. A second branch path 6 branched from the second position 32 close to the frictional engagement element 2 and connected to the accumulator 4, a first check valve 7 provided in the first branch path 5, and a second branch path provided in the second branch path 6. A check valve 8 is provided.

  The accumulator 4 is a piston type and includes a cylindrical case 41 and a piston 42 slidably accommodated in the case 41. The interior of the case 41 is partitioned into a pressure accumulation chamber 43 and a back pressure chamber 44 by a piston 42, and the pressure accumulation chamber 43 communicates with the first branch path 5 and the second branch path 6 through a port 45 formed in the case 41. Further, the back pressure chamber 44 accommodates a spring 46 that biases the piston 42 in a direction in which the pressure accumulating chamber 43 is reduced. In a state where no oil is stored in the pressure accumulating chamber 43, the piston 42 is pressed against the end surface of the case 41 by the urging force of the spring 46, and the volume of the pressure accumulating chamber 43 becomes 0. However, in FIG. The piston 42 is depicted in a state of being separated from the end surface of the case 41.

  The accumulator 4 is disposed in the transmission in a state where the whole is immersed in oil. Thus, oil is always filled between the first check valve 7 and the accumulator 4 and between the second check valve 8 and the accumulator 4.

  When oil is supplied to the pressure accumulating chamber 43 and the force by which the oil pushes the piston 42 exceeds the biasing force of the spring 46, the piston 42 is displaced in the direction of expanding the pressure accumulating chamber 43, and the oil is stored in the pressure accumulating chamber 43. Conversely, when the force with which the oil pushes the piston 42 is less than the biasing force of the spring 46, the oil in the pressure accumulating chamber 43 is discharged from the port 45.

  The operating pressure range of the accumulator 4 alone (hydraulic pressure range in which the piston 42 is displaced) is set such that the fastening pressure of the frictional engagement element 2 is included between the upper limit and the lower limit of the operating pressure range. Specifically, the pressure receiving area of the piston 42 and the biasing force of the spring 46 are set so that the operating pressure range of the accumulator 4 alone is within such a range.

  In this example, since the fastening pressure of the frictional engagement element 2 is 0.2 MP, the operating pressure range of the accumulator 4 alone is set to 0.15 to 0.25 MP to include this.

  In this example, the piston type accumulator 4 is used, but other types of accumulators such as a bluff type accumulator and a diaphragm type accumulator may be used instead.

  The first check valve 7 includes a valve seat 71 provided on the first position 31 side, and a check ball 73 that is disposed to face the valve seat 71 and is urged toward the valve seat 71 by a spring 72. Is done.

  When the hydraulic pressure in the pressure accumulation chamber 43 is lower than the hydraulic pressure in the first position 31, the first check valve 7 responds to the differential pressure in the first check valve 7 (= the hydraulic pressure in the first position 31-the hydraulic pressure in the pressure accumulation chamber 43). Open and close.

  That is, when the force with which the check ball 73 is pressed by the differential pressure is smaller than the biasing force of the spring 72, the check ball 73 is pressed against the valve seat 71 by the biasing force of the spring 72, and the first check valve 7 is closed. On the other hand, when the force with which the check ball 73 is pushed by the differential pressure exceeds the biasing force of the spring 72, the check ball 73 moves away from the valve seat 71 against the biasing force of the spring 72, and the first check valve 7 opens. Then, the flow of oil from the first position 31 toward the pressure accumulation chamber 43 is allowed.

  The biasing force of the spring 72 is set to a value larger than 0. Preferably, the first check valve 7 is opened after the hydraulic pressure of the frictional engagement element 2 becomes 0.2 MPa or higher, which is the engagement pressure of the frictional engagement element 2. Set to do. In the present embodiment, since the lower limit of the operating pressure range of the accumulator 4 alone is 0.15 MPa, if the biasing force of the spring 72 is set to at least 0.05 MPa or more, the hydraulic pressure of the frictional engagement element 2 is reduced to that of the frictional engagement element 2. The first check valve 7 can be opened after the fastening pressure becomes 0.2 MPa or more.

  In this example, the biasing force of the spring 72 is set to 0.2 MPa with a margin. Therefore, when the hydraulic pressure of the frictional engagement element 2 is lower than 0.35 MPa and the differential pressure in the first check valve 7 is lower than 0.2 MPa, the first check valve 7 is closed. On the other hand, the first check valve 7 is opened when the hydraulic pressure of the frictional engagement element 2 becomes 0.35 MPa or more and the differential pressure in the first check valve 7 becomes 0.2 MPa or more.

  That is, the first check valve 7 opens when the hydraulic pressure of the frictional engagement element 2 reaches 0.35 MPa or more as a predetermined pressure, and allows only the flow of oil from the first position 31 toward the pressure accumulation chamber 43. At this time, since the hydraulic pressure in the pressure accumulating chamber 43 becomes 0.15 MPa or more which is the lower limit of the operating pressure range of the accumulator 4 alone, pressure accumulation by the accumulator 4 is also started.

  On the other hand, the second check valve 8 is configured by a valve seat 81 provided on the accumulator 4 side and a check ball 82 disposed to face the valve seat 81.

  When the hydraulic pressure in the pressure accumulating chamber 43 is lower than the hydraulic pressure in the second position 32, the check ball 82 is pressed against the valve seat 81 and the second check valve 8 is closed. On the other hand, when the hydraulic pressure in the pressure accumulating chamber 43 is higher than the hydraulic pressure in the second position 32, the check ball 82 is separated from the valve seat 81 and the second check valve 8 is opened.

  That is, the second check valve 8 allows only the oil flow from the pressure accumulation chamber 43 toward the second position 32.

  Next, the operation of the pressure accumulating structure 100 will be described.

  FIG. 2 is a diagram showing a change in hydraulic pressure over time when oil is supplied to the frictional engagement element 2 in the released state.

  As shown in FIG. 4, the thick broken line in the figure indicates the hydraulic pressure of the frictional engagement element 2 when the pressure accumulation chamber 43 of the accumulator 4 is directly connected to the oil passage 3 and oil is supplied to the frictional engagement element 2 in the released state as shown in FIG. 4. The time change is shown. The operating pressure range of the accumulator 4 alone is 0.15 to 0.25 MPa, similar to the pressure accumulating structure.

  In the comparative example, when the hydraulic pressure of the frictional engagement element 2 exceeds 0.15 MPa, pressure accumulation by the accumulator 4 is started, and the hydraulic pressure of the frictional engagement element 2 increases gradually. In order to fasten the frictional engagement element 2, it is necessary to increase the hydraulic pressure of the frictional engagement element 2 to 0.2 MPa while the increase in hydraulic pressure is moderate, and a fastening delay of the frictional engagement element 2 occurs.

  On the other hand, the change in the oil pressure when the pressure accumulating structure 100 is adopted is shown by a thick solid line, and the fastening delay that occurs in the comparative example can be reduced.

  The change in hydraulic pressure when the pressure accumulating structure 100 is adopted will be described. When the driver operates the shift lever at time t11 and the hydraulic pressure switching valve 1 is switched to a position where oil is supplied to the frictional engagement element 2, frictional engagement is achieved. The supply of oil to the element 2 is started, and the hydraulic pressure of the frictional engagement element 2 starts to rise. Since the accumulator 4 does not accumulate pressure until the first check valve 7 is opened, the hydraulic pressure of the frictional engagement element 2 is such that the differential pressure at the first check valve 7 is 0.2 MPa and the first check valve 7 It quickly rises to 0.35 MPa, which opens the valve.

  On the way, the frictional engagement element 2 is fastened when the hydraulic pressure of the frictional engagement element 2 reaches 0.2 MPa, which is the fastening pressure of the frictional engagement element 2 (time t12), so that the frictional engagement element 2 is also fastened. . During this time, since the hydraulic pressure in the pressure accumulating chamber 43 is always lower than the hydraulic pressure in the second position 32, the second check valve 8 remains closed.

  FIG. 3A shows the flow of oil between times t11 and t13. During this time, if the hydraulic pressure between the pressure accumulation chamber 43 and the first check valve 7 is lower than the first position 31, the first check valve 7 is slightly opened to increase the hydraulic pressure between the pressure accumulation chamber 43 and the first check valve 7. When the differential pressure becomes lower than 0.2 MPa, the valve is repeatedly closed. However, since the oil is an incompressible fluid, the drop in the differential pressure occurs instantaneously, and the oil moves through the first check valve 7. In this specification, the first check valve 7 is treated as being closed because it is extremely small.

  When the hydraulic pressure of the frictional engagement element 2 reaches 0.35 MPa at time t13, the differential pressure in the first check valve 7 exceeds 0.2 MPa, and the first check valve 7 is opened. When the first check valve 7 is opened, oil flows from the first position 31 to the pressure accumulating chamber 43 via the first check valve 7. Further, since the hydraulic pressure in the pressure accumulating chamber 43 exceeds 0.15 MPa, which is the lower limit of the operating pressure range, pressure accumulation by the accumulator 4 is started.

  When the hydraulic pressure of the frictional engagement element 2 reaches 0.45 MPa at time t14, the hydraulic pressure in the accumulator 4 reaches 0.25 MP, which is the upper limit of the operating pressure range, and the accumulator 4 stops accumulating pressure.

  FIG. 3B shows the oil flow between times t13 and t14. During this time, since the hydraulic pressure is used to displace the piston 42 of the accumulator 4, the hydraulic pressure of the frictional engagement element 2 rises more slowly than during the time t11 to t13.

  As described above, in the pressure accumulating structure 100, the operating pressure range of the accumulator 4 alone is set to include 0.2 MPa that is the fastening pressure of the frictional engagement element 2, but oil is supplied to the frictional engagement element 2. In this case, the operating pressure range of the accumulator 4 with respect to the hydraulic pressure of the frictional engagement element 2 is raised by the action of the first check valve 7, and the accumulator 4 operates while the hydraulic pressure of the frictional engagement element 2 changes from 0.35 to 0.45 MPa. Will do.

  Thereby, according to the said pressure accumulation structure 100, before the accumulator 4 act | operates, the friction fastening element 2 can be fastened and the fastening delay of the friction fastening element 2 by providing the accumulator 4 can be eliminated.

  On the other hand, FIG. 5 is a diagram showing a change in hydraulic pressure over time when oil is discharged from the frictional engagement element 2 in the engaged state.

  When the driver operates the shift lever at time t21 and the hydraulic pressure switching valve 1 is switched to the position where oil is discharged from the frictional engagement element 2, oil discharge from the frictional engagement element 2 is started. The hydraulic pressure begins to drop. At this time, since the hydraulic pressure in the second position 32 is higher than the hydraulic pressure in the pressure accumulating chamber 43, the second check valve 8 remains closed.

  When the hydraulic pressure of the frictional engagement element 2 decreases to 0.25 MPa at time t22 and becomes equal to the hydraulic pressure of the pressure accumulating chamber 43, the second check valve 8 is opened, and oil discharge from the pressure accumulating chamber 43 to the oil passage 3 is started. The FIG. 6 shows the oil flow at this time.

  The oil is continuously discharged from the pressure accumulating chamber 43 to the oil passage 3 until the oil pressure of the frictional engagement element 2 is reduced to 0.15 MPa, whereby the oil pressure is reduced from 0.25 MPa to 0 than when the oil pressure is decreased from 0.45 MPa to 0.25 MPa. .Lowering of oil pressure when decreasing to 15 MPa.

  When the hydraulic pressure of the frictional engagement element 2 decreases to 0.15 MPa at time t23, the decrease rate of the hydraulic pressure of the frictional engagement element 2 returns to the original value and then quickly decreases to zero.

  As described above, when the oil is discharged, the operating pressure range of the accumulator 4 becomes the same as the operating pressure range of the accumulator 4 alone, and the hydraulic pressure can be gradually lowered so as to straddle the fastening pressure of the frictional engagement element 2.

  Then, the effect by employ | adopting the said pressure accumulation structure 100 is demonstrated.

  In the above embodiment, the pressure accumulating structure 100 provided in the oil passage 3 connecting the hydraulic pressure switching valve 1 and the frictional engagement element 2 includes the engagement pressure of the frictional engagement element 2 in the operating pressure range as a single unit, and the pressure accumulation chamber is provided inside. The accumulator 4 in which 43 is partitioned, the first and second branch paths 5 and 6 that branch from the middle of the oil path 3 and connect to the pressure accumulating chamber 43, and the first branch path 5, When the hydraulic pressure exceeds a predetermined pressure, the valve is opened, and the first check valve 7 that allows only the flow of oil from the oil passage 3 toward the pressure accumulation chamber 43 and the second branch passage 6 are arranged. And a second check valve 8 that allows only the flow of oil toward.

  According to this configuration, when accumulating oil, pressure accumulation by the accumulator 4 is not performed until the first check valve 7 is opened. Therefore, pressure accumulation on the accumulator 4 is performed before the frictional engagement element 2 is fastened. This reduces or eliminates the engagement delay of the frictional engagement element 2 and improves the start response of the vehicle. Conversely, when oil is discharged, the hydraulic pressure is gradually lowered across the fastening pressure of the frictional engagement element 2, the frictional engagement element 2 is suddenly released, and the shock caused by the rapid release of the twist of the drive system components can be suppressed. (Operational effect corresponding to claim 1).

  The predetermined value was set to be equal to or higher than the fastening pressure of the frictional engagement element 2. Thereby, at the time of oil supply, the accumulator 4 operates after the frictional engagement element 2 is engaged. Therefore, the accumulation delay of the frictional engagement element 2 due to accumulation of pressure by the accumulator 4 before the frictional engagement element 2 is engaged is prevented. (Effects corresponding to claim 2).

  Note that setting the predetermined value to be equal to or higher than the engagement pressure of the frictional engagement element 2 is not an essential configuration, and at least the differential pressure in the first check valve 7 (= the hydraulic pressure at the first position 31−the hydraulic pressure at the pressure accumulation chamber 43). If the predetermined value is set so that the first check valve 7 is opened when is greater than 0, there is an effect of delaying the timing at which the accumulator 4 starts accumulating and reducing the engagement delay of the friction engagement element 2. Played.

  The embodiment of the present invention has been described above, but the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

  For example, in the above embodiment, the first branch path 5 is branched from the first position 31 in the middle of the oil path 3, and the second branch path 6 is closer to the frictional engagement element 2 than the first position 31 of the oil path 3. However, the first branch path 5 and the second branch path 6 may be bundled and branched from a common position on the oil path 3. That is, the first check valve 7 and the second check valve 8 need only be provided in parallel between the pressure accumulating chamber 43 and the oil passage 3.

1: Hydraulic switching valve 2: Friction engagement element 3: Oil path 4: Accumulator 5: First branch path 6: Second branch path 7: First check valve 8: Second check valve 31: First position 32: Second Position 43: Accumulation chamber 100: Accumulation structure

Claims (2)

In an automatic transmission, a pressure accumulating structure provided in an oil passage connecting a hydraulic pressure switching valve and a friction engagement element,
An accumulator that includes a fastening pressure of the friction fastening element in a single working pressure range, and in which a pressure accumulating chamber is partitioned;
A first branch path and a second branch path branched from the middle of the oil path and connected to the pressure accumulation chamber;
A first check valve that is disposed in the first branch passage and opens when the oil pressure of the frictional engagement element is equal to or higher than a predetermined pressure, and allows only a flow of oil from the oil passage toward the pressure accumulation chamber;
A second check valve disposed in the second branch path and allowing only the flow of oil from the pressure accumulation chamber toward the oil path;
An accumulator structure characterized by comprising The pressure accumulating structure according to claim 1,
The predetermined pressure is set to be equal to or higher than a fastening pressure of the frictional engagement element;
An accumulator structure characterized by that.

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