JP4946078B2 - Fluid pressure control device for automatic transmission - Google Patents

Description

  The present invention relates to a fluid pressure control device for an automatic transmission, and more particularly to a technique for controlling the engagement timing of a friction engagement element provided in an automatic transmission.

  An automatic transmission normally includes a plurality of friction engagement elements, and a plurality of shift speeds are selectively established by controlling disengagement of the plurality of friction engagement elements. The frictional engagement element of the automatic transmission is controlled to be disengaged by controlling the fluid pressure of the working fluid supplied to the frictional engagement element. Since the working oil is usually used as the working fluid, the following description will be made assuming that the working fluid is the working oil.

  The hydraulic control device used for controlling the friction engagement element provided in the automatic transmission includes a pressure regulating valve for regulating the operating hydraulic pressure. By controlling the pressure regulating valve, the initial engagement is performed. Supplies a low control pressure to the frictional engagement element and gradually increases the control pressure, thereby completing the engagement while suppressing a shock associated with the shift.

As this hydraulic control device, a switching valve is provided between the pressure regulating valve and the friction engagement element to switch the pressure supplied to the friction engagement element between the control pressure regulated by the pressure regulation valve or the original pressure. What you have is known. For example, the apparatus described in Patent Document 1 is this. In the apparatus described in Patent Document 1, a control pressure is supplied at the beginning of friction engagement, and the control pressure is gradually increased. Finally, the switching valve is switched, and the original pressure (line pressure) is supplied to the friction engagement element. As a result, it is possible to improve both the hydraulic controllability during the shift transition period and secure the torque capacity after the shift is completed.
JP 2000-337486 A

  In the case of the apparatus of Patent Document 1, the position of the switching valve is determined by the magnitude relationship between the control pressure regulated by the pressure regulating valve and the urging force of the spring provided in the switching valve. When the urging force of the spring is larger than the control pressure, the control pressure is supplied to the friction engagement element, and when the control pressure becomes larger, the original pressure is supplied to the friction engagement element.

  That is, in the case of the device of Patent Document 1, the pressure at which the hydraulic pressure supplied to the friction engagement element is switched from the control pressure to the original pressure is a fixed value determined in advance.

  By the way, the required shelf pressure of the friction engagement element changes in accordance with the required torque capacity. That is, when the required torque capacity is large, the required shelf pressure increases, and when the required torque capacity is small, the required shelf pressure decreases. The required torque capacity varies depending on, for example, the throttle opening.

  Since the required shelf pressure changes in this way, the pressure supplied to the friction engagement element needs to be a control pressure that is an adjustable pressure up to the required shelf pressure. Therefore, when the pressure for switching the hydraulic pressure supplied to the friction engagement element from the control pressure to the original pressure is a fixed value, as in the device described in Patent Document 1, the required shelf pressure is set to the fixed value. Must be set for high cases. As a result, the hydraulic controllability during the shift transition period was insufficient.

  The present invention has been made based on this situation, and an object of the present invention is an automatic transmission capable of switching the pressure supplied to the friction engagement element from the control pressure to the original pressure at an arbitrary timing. It is to provide a working fluid control device.

To achieve the object, the invention according to claim 1 is a fluid pressure control device for an automatic transmission that controls disengagement of a plurality of friction engagement elements provided in the automatic transmission, and is inputted. A plurality of pressure regulating valves controlled to regulate the original pressure to a control pressure to be supplied to the friction engagement element, and disposed between the pressure regulation valve and the friction engagement element, to the friction engagement element A switching valve capable of taking a first position in which the pressure to be supplied is the original pressure and a second position in which the pressure to be supplied to the friction engagement element is the control pressure; The switching valve that switches and supplies the source pressure and the control pressure to the friction engagement element that is frictionally engaged is controlled by a pressure regulating valve that is not used to regulate the control pressure that is supplied to the friction engagement element at the time of shifting. As a switching valve, supplied to the switching valve When using an underlap spool valve in which the pressure and the control pressure can simultaneously communicate with the friction engagement element, and the control pressure supplied to the underlap spool valve is controlled to be a predetermined switching pressure, When the friction engagement element is continuously changed to the switching pressure and the friction engagement element is engaged, the control pressure is supplied to the friction engagement element with the switching valve as the second position, and the control pressure is switched to the switching pressure. After the control pressure is changed to the switching pressure, the original pressure is supplied to the friction engagement element with the switching valve as the first position .

In this way, the switching valve that supplies the friction engagement element that is frictionally engaged during the shift to the predetermined shift stage by switching the source pressure and the control pressure is supplied to the friction engagement element at the shift. If it controls by the pressure regulation valve which is not used in order to regulate pressure, a switching valve can be switched at arbitrary timings. Therefore, the pressure supplied to the friction engagement element can be switched from the control pressure to the original pressure at an arbitrary timing.
Further, since the underlap spool valve is used as the switching valve, it is difficult for the foreign material to lock at an intermediate position, so the possibility of supply failure or discharge failure can be reduced.

  As the pressure regulating valve, a first pressure regulating valve and a second pressure regulating valve may be provided as a set as in claim 2, or a single electromagnetic valve is provided as in claim 3. May be. In addition, in the case of Claim 2, an amplification mechanism is comprised by the 1st pressure regulation valve and the 2nd pressure regulation valve.

  According to a second aspect of the present invention, as the pressure regulating valve, a modulated pressure obtained by reducing the original pressure is supplied and electrically controlled to regulate the modulated pressure to obtain the first control pressure. The first pressure regulating valve to be output and the original pressure are supplied and controlled by the first control pressure, thereby adjusting the original pressure to a second control pressure larger than the first control pressure and the friction. A plurality of second pressure regulating valves that output to the engaging element, and the switching control of the switching valve is performed by the first pressure regulating valve that is not used to control the second pressure regulating valve during a shift. .

  According to a third aspect of the present invention, as the pressure regulating valve, an electromagnetic valve that supplies a source pressure and is electrically controlled to regulate the source pressure to a control pressure and output it to the friction engagement element. And the switching control of the switching valve is performed by the electromagnetic valve that is not used to regulate the control pressure supplied to the friction engagement element at the time of shifting.

  According to the invention described in claim 3, since the number of pressure regulating valves is reduced, the apparatus can be reduced in size and weight.

As described above, the invention according to claim 1 can switch the switching valve at an arbitrary timing. Further, the required torque capacity of the friction engagement element changes according to the throttle opening. Therefore, as described in claim 4 , when the control pressure reaches a predetermined switching pressure, the switching valve is switched from the first position to the second position by the pressure regulating valve. And it is preferable that the switching pressure changes according to the throttle opening. In this way, the shift shock can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a hydraulic control apparatus 10 according to the first embodiment. The automatic transmission controlled by the hydraulic control device 10 includes friction engagement elements such as a clutch C1 and a brake B2. These friction engagement elements C1 and B2 are composed of a plurality of wet friction plates.

  The hydraulic control device 10 includes a plurality (two in the figure) of control valves 20 and 30 and a plurality of solenoid valves 22 and 32 corresponding to the number of friction engagement elements provided in the automatic transmission. Yes.

  The solenoid valves 22 and 32 have a structure capable of continuously changing the output pressure of a linear solenoid valve, a duty solenoid valve or the like, and the line pressure PL which is the original pressure is reduced at the input port. The modulated pressure Pm is input. These solenoid valves 22 and 32 function as a first pressure regulating valve, and are controlled by an ECU (electronic control unit) 40 to regulate the modulated pressure Pm and output a first control pressure Pc1.

  The control valves 20 and 30 function as a second pressure regulating valve, and the line pressure PL is input to the input port, and the first control pressure Pc1 is input to the control port. Due to the balance between the first control pressure Pc1 and the spring, the magnitude of the second control pressure Pc2, which is the output pressure, continuously changes.

  The second control pressure Pc2 is supplied to the friction engagement elements C1 and B2, and the engagement of the friction engagement elements C1 and B2 is controlled by controlling the magnitude of the second control pressure Pc2. . Note that the line pressure PL (D) input to the control valve 30 for controlling the disengagement of the clutch C1 is supplied only in the forward travel range (D range) and is in the reverse travel range (R range). Not supplied. On the other hand, the line pressure PL (R) input to the control valve 20 for controlling the disengagement of the brake B2 is supplied only during the reverse travel range and not supplied during the forward travel range. The solenoid valves 22 and 32 are supplied with a modulated pressure Pm regardless of the shift position.

  A shift valve 50 functioning as a switching valve is provided in the middle of the oil passage 42 connecting the control valve 20 and the brake B2, that is, between the control valve 20 and the brake B2.

  FIG. 2 is an enlarged sectional view of the shift valve 50. As shown in FIG. 2, the shift valve 50 includes first and second input ports 51 and 52, and the second control pressure Pc <b> 2 is input to the first input port 51, and the second input port 52. Is input with the line pressure PL (R). The switching valve 50 has first and second control ports 53 and 54, and the first control port 53 is connected to the output port of the solenoid valve 32 via the oil passage 44. Accordingly, the first control pressure Pc1 regulated by the solenoid valve 32 is input to the first control port 53. On the other hand, the line pressure PL (D) is input to the second control port 54. The position of the spool 55 is controlled by the magnitude of the pressure input to these two control ports 53 and 54. A spring 56 is provided on the second control port 54 side in the axial direction of the spool 55.

  The shift valve 50 receives a first position where the first input port 51 to which the second control pressure Pc2 is input is communicated with an output port 57 that outputs hydraulic pressure to the brake B2, and a line pressure PL (R). The second position where the second input port 52 communicates with the output port 57 can be taken. Hereinafter, the pressure output from the output port 57 and input to the brake B2 is referred to as brake pressure.

  The shift valve 50 has an underlap spool valve structure. That is, even when the spool 55 as shown in FIG. 2 is in the neutral position, the input ports 51 and 52 are partially opened. In other words, if the axial length between the two large diameter portions of the spool 55 is d1, and the shortest axial distance between the two input ports 51 and 52 is d2, d1> d2. As described above, by using the underlap spool valve, it is possible to prevent the spool 55 from being locked due to foreign matters. Accordingly, the spool 55 is locked at the intermediate position, and the brake pressure cannot be reduced. Conversely, the spool 55 cannot be set to the first position or the second position, and an appropriate brake pressure is supplied. It is possible to prevent a situation where it is impossible to do so.

  When an underlap spool valve is used as the shift valve 50 as in this embodiment, the input port is not only in the case where the spool 55 is located in the first position or the second position, but also in the intermediate position as shown in FIG. Although the leak pressure from 51 and 52 is supplied to the brake B2, the shift valve 50 is only switched to either the first position or the second position, and intermediate control is not performed. Is not supplied to the brake B2.

  Returning to FIG. 1, the ECU 40 is a computer having a CPU, a ROM, a RAM, and the like inside (not shown), and receives a shift command signal Sc, a throttle opening signal St indicating the throttle opening θ, and the like. In order to disengage a plurality of friction engagement elements provided in the automatic transmission based on the shift command signal Sc, solenoid valves provided corresponding to the plurality of friction engagement elements are provided. Control. By controlling the solenoid valve, the line pressure PL is regulated in the control valve and output to the predetermined friction engagement element as the second control pressure Pc2.

  Further, when it is necessary to engage the brake B2 at the time of shifting, the control of the shift valve 50 provided between the brake B2 and the control valve 20 is also performed by controlling the solenoid valve 32.

  FIG. 3 is an engagement operation table of the automatic transmission including the clutch C1 and the brake B2. In the figure, ◯ indicates engagement, and a blank indicates release. As shown in FIG. 3, the brake B2 is engaged when the R range, that is, the reverse shift speed is established. On the other hand, the clutch C1 is opened when in the R range. Accordingly, if C1 is in the open state even at the gear position before the shift, the solenoid valve 32 does not adjust the control pressure supplied to the friction engagement element during the shift to the R range. Therefore, the solenoid valve 32 can be used for switching control of the shift valve 50 when shifting to the R range. Note that the line pressure PL (D) is not supplied to the control valve 30 when shifting to the R range, so that even if the first control pressure Pc1 is output from the solenoid valve 32, the clutch C1 is engaged. It wo n’t fit.

  When a shift valve is provided between the friction engagement element and the control valve, not only the brake B2 described above, the shift is performed by a solenoid valve that does not regulate the control pressure supplied to the friction engagement element during a shift. Perform valve switching control.

  When the ECU 40 engages a predetermined friction engagement element by controlling the solenoid valve, first, the required shelf pressure Pf is determined based on the throttle opening signal St. The throttle opening θ is a parameter that changes in relation to the input torque input to the automatic transmission, and the required shelf pressure Pf increases as the input torque increases. Therefore, the required shelf pressure Pf is determined to be larger as the throttle opening θ is larger.

  Next, with the shift valve 50 in the first position, the solenoid valve 22 is controlled to increase the first control pressure Pc1 output from the solenoid valve 22. Since the first control pressure Pc1 is input to the control port of the control valve 20, when the first control pressure Pc1 is increased, the second control pressure Pc2 output from the control valve 20 is also increased.

  Then, the second control pressure Pc2 is increased to the required shelf pressure Pf. This second control pressure Pc2 is input to the brake B2 as a brake pressure because the shift valve 50 is in the first position. Accordingly, the brake pressure rises to the required shelf pressure Pf corresponding to the second control pressure Pc2.

  When the brake pressure reaches the required shelf pressure Pf, the brake B2 starts frictional engagement. This engagement start is determined from, for example, a change in turbine rotational speed. When it is determined that the engagement is started, the ECU 40 controls the solenoid valve 32 to generate a predetermined first control pressure Pc1 that becomes a valve switchable pressure. This valve switchable pressure is set to a pressure sufficiently higher than the urging force of the spring 54 of the shift valve 50.

  The first control pressure Pc1 (valve switchable pressure) is input to the first control port 53 of the shift valve 50 via the oil passage 44, whereby the shift valve 50 is moved from the first position to the second position. Therefore, the line pressure PL (R) is supplied to the brake B2. When the line pressure PL (R) is supplied to the brake B2, the engagement operation of the brake B2 is completed. In addition, since the magnitude of the line pressure PL (R) is adjusted so as to be a required engagement pressure according to the throttle opening θ, sufficient engagement torque is obtained by switching to the line pressure PL (R). Is obtained.

  FIGS. 4A and 4B are diagrams illustrating the relationship between the second control pressure Pc2 and the brake pressure at the time of shifting. FIG. 4A shows a case where the throttle opening θ is high, and FIG. 4B shows a case where the throttle opening θ is low. At the time of opening.

  Below the required shelf pressure Pf, the second control pressure Pc2 is input as the brake pressure, so that the brake pressure corresponds to the second control pressure Pc2, as shown in FIGS. 4 (a) and 4 (b).

  On the other hand, at the required shelf pressure Pf or higher, the shift valve 50 is switched to the second position. That is, the shift valve 50 is switched to the second position using the necessary shelf pressure Pf as the switching pressure. Therefore, the brake pressure becomes the line pressure PL (R).

  As shown in FIG. 4, the required shelf pressure Pf varies depending on the throttle opening θ, and the required shelf pressure Pf increases as the throttle opening θ increases. Since this necessary shelf pressure Pf is the switching pressure of the shift valve 50, the switching pressure also changes depending on the throttle opening θ.

  On the other hand, in the present embodiment, the shift valve 50 that switches and supplies the line pressure PL (R) and the second control pressure Pc2 to the brake B2 that is frictionally engaged during the shift to the reverse shift stage, Since the control is performed by the solenoid valve 32 that is not used in the shift, the shift valve 50 can be switched at an arbitrary timing. Therefore, even if the required shelf pressure Pf changes as the throttle opening θ changes, the pressure supplied to the brake B2 at the required shelf pressure Pf is switched from the second control pressure Pc2 to the line pressure PL (R). Can do. Therefore, the controllability during the shift transition period is improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, The following embodiment is also contained in the technical scope of this invention, and also the summary other than the following is also included. Various modifications can be made without departing from the scope.

  For example, in the above-described embodiment, the brake B2 is controlled in the hydraulic pressure supplied by the amplification mechanism including the control valve 20 and the solenoid valve 22 that are paired with each other. The control bubble 20 may not be provided. In this case, the solenoid valve 22 regulates the pressure corresponding to the second control pressure Pc2 of the above-described embodiment. In this way, the device can be reduced in size and weight because the control valve 20 is not provided. Further, in the case of shifting to a predetermined gear position where it is not necessary to regulate the control pressure by the solenoid valve 22 and supply it to the brake B2, the solenoid valve 22 is connected to another friction engagement element (not shown). Therefore, it may be used for switching a shift valve (switching valve) provided for the purpose. In this case, the solenoid valve 22 functions as the electromagnetic valve according to claim 3.

  In the above-described embodiment, the case where the reverse gear is established has been described as an example. However, the present invention is not particularly limited to the gear that is established, and may be the forward gear, and may be a parking range or a neutral range. There may be.

  Further, in the hydraulic control device 10 of the above-described embodiment, the second control pressure Pc2 that is regulated in the control valve 20 based on the first control pressure Pc1 increases as the first control pressure Pc1 increases. However, as in Patent Document 1, as the first control pressure Pc1 (solenoid pressure Psol in Patent Document 1) increases, the second control pressure Pc2 (control pressure PS in Patent Document 1) increases. It may be lowered.

1 is a schematic diagram of a hydraulic control device 10 according to a first embodiment of the present invention. It is an expanded sectional view of the shift valve 50 of FIG. 2 is an engagement operation table of an automatic transmission including a clutch C1 and a brake B2 of FIG. It is a figure which illustrates the relationship between the 2nd control pressure Pc2 at the time of gear shifting, and a brake pressure, (a) is when the throttle opening (theta) is a high opening degree, (b) is when the throttle opening (theta) is a low opening degree. Is. It is the schematic of the hydraulic control apparatus of 2nd Embodiment of this invention.

Explanation of symbols

10: Hydraulic control device (fluid pressure control device)
20: Control valve (second pressure regulating valve)
22: Solenoid valve (first pressure regulating valve, solenoid valve)
32: Solenoid valve (first pressure regulating valve, solenoid valve)
50: Shift valve (switching valve)

Claims (4)

A fluid pressure control device for an automatic transmission that controls disengagement of a plurality of friction engagement elements provided in the automatic transmission,
A plurality of pressure regulating valves controlled to regulate the input source pressure to the control pressure supplied to the friction engagement element;
A first position that is disposed between the pressure regulating valve and the friction engagement element and uses the pressure supplied to the friction engagement element as the original pressure; and the pressure supplied to the friction engagement element as the control pressure And a switching valve capable of taking a second position
In order to adjust the control pressure supplied to the friction engagement element at the time of a shift, the switching valve for switching the supply pressure and the control pressure to the friction engagement element to be frictionally engaged when shifting to a predetermined shift stage Switching control is performed by a pressure regulator that is not used.
As the switching valve, an underlap spool valve capable of simultaneously communicating the original pressure supplied to the switching valve and the control pressure to the friction engagement element, and the control pressure supplied to the underlap spool valve are used. Is continuously changed up to the switching pressure when controlled to be a predetermined switching pressure ,
When engaging the friction engagement element, the control pressure is continuously changed to the switching pressure while supplying the control pressure to the friction engagement element with the switching valve as the second position, After the pressure becomes the switching pressure, the original pressure is supplied to the friction engagement element with the switching valve as the first position . As the pressure regulating valve, a modulated pressure obtained by reducing the original pressure is supplied and electrically controlled to regulate the modulated pressure and output a first controlled pressure; and The original pressure is supplied and controlled by the first control pressure, whereby the original pressure is adjusted to a second control pressure larger than the first control pressure and output to the friction engagement element. There are multiple pressure regulating valves,
2. The fluid pressure control device for an automatic transmission according to claim 1, wherein the switching control of the switching valve is performed by the first pressure regulating valve that is not used for controlling the second pressure regulating valve at the time of shifting. As the pressure regulating valve, an electromagnetic valve is provided that is supplied with a source pressure and is electrically controlled to regulate the source pressure to a control pressure and output it to the friction engagement element;
2. The fluid pressure control device for an automatic transmission according to claim 1, wherein the switching control of the switching valve is performed by the electromagnetic valve that is not used for regulating the control pressure supplied to the frictional engagement element at the time of shifting. . The switching valve is adapted to be switched from the first position to the second position by the pressure regulating valve when the control pressure becomes a predetermined switching pressure, and
Fluid pressure control device for an automatic transmission according to any one of claims 1 to 3 the switching pressure is characterized in that is adapted to change in accordance with the throttle opening.

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