Patent Application
20110132717
The present invention relates to a hydraulic control device of an automatic transmission that is mounted on, e.g., a vehicle, and more particularly to a hydraulic control device of an automatic transmission which regulates a working pressure that engages and disengages a clutch by the difference from a circulation pressure of a starting device, by using a pressure-regulating solenoid valve.
In recent years, an automatic transmission mounted on, e.g., a vehicle, has been becoming common including a hydraulic power transmission device such as a torque converter, and also including a lockup clutch for locking up the hydraulic power transmission device in order to reduce transmission loss in the hydraulic power transmission device. Engagement/disengagement control and slip control of this lockup clutch are performed based on the difference between a circulation pressure PCIR of oil that circulates as a working fluid of the hydraulic power transmission device (an on-pressure PON that acts on the engaging side), and a working pressure PAPP that is electronically controlled (an off-pressure POFF that acts on the disengaging side).
In related art, the working pressure PAPP is generated by a control valve that is controlled by an output pressure of a linear solenoid valve that uses, e.g., a modulator pressure, namely a line pressure controlled to a constant pressure (alternatively, the line pressure or a secondary pressure) as a source pressure. With recent improvement in output performance of linear solenoid valves, however, such a device is proposed that uses the output pressure of the linear solenoid valve as it is as the working pressure PAPP (see Patent Document 1). This eliminates the need for the control valve, and enables a more compact hydraulic control device to be implemented.
[Related Art Document]
[Patent Document]
[Patent Document 1] Japanese Patent Application Publication No. JP-A-2006-242347
In such a device that regulates the working pressure PAPP by the linear solenoid valve, the circulation pressure PCIR is input as a feedback pressure to an oil chamber (120) provided in the linear solenoid valve, and the working pressure PAPP that is output is input as a feedback pressure to an oil chamber (122) provided on the opposite side via a spool (114).
However, as shown in
Thus, the relation between a feedback force of the oil chamber 112a that receives the circulation pressure PCIR and a feedback force of the oil chamber 112b that receives the working pressure PAPP is represented by the following expression.
ΔPAPP=(A1−A2)/A1·ΔPCIR (1)
On the other hand, if a large driving force is transmitted from an engine to the torque converter while the vehicle is stopped or is moving at a low speed such as when the vehicle is started on an uphill road or the like, large differential rotation is produced between a pump impeller that rotates at the engine speed, and a turbine runner whose rotation is stopped. Thus, a phenomenon tends to occur that the internal pressure in the torque converter first increases due to stirring of oil, and then decreases rapidly.
That is, when the vehicle is started or the like, as shown in
In particular, in recent years, a device is proposed without the hydraulic power transmission device such as the torque converter, which enables starting of the vehicle while slip-controlling a starting clutch. In such a device, however, the circulation pressure of the starting clutch varies upon such starting of the vehicle as described above, and thus the differential pressure of the starting clutch may not be maintained at an intended value, which may cause shocks or vibrations upon starting of the vehicle.
Thus, it is an object of the present invention to provide a hydraulic control device of an automatic transmission which is capable of accurately performing engagement/disengagement control and slip control of a clutch even if a circulation pressure varies.
According to the present invention (see, e.g.,
The present invention (see, e.g.,
Specifically, the present invention (see, e.g.,
The present invention (see, e.g.,
The present invention (see, e.g.,
Note that the reference numerals in the parentheses are shown for reference to the drawings, and are given for convenience to facilitate understanding of the invention. Thus, these reference numerals do not affect the structure described in the claims.
According to the present invention of claim 1, the pressure-receiving area of the first feedback oil chamber and the pressure-receiving area of the second feedback oil chamber are set equal to each other in the spool. Thus, the oil pressure acting force of the working pressure of the first feedback oil chamber and that of the circulation pressure of the second feedback oil chamber can be equal to each other, whereby engagement/disengagement control and slip control of the clutch can be accurately performed.
According to the present invention of claim 2, the starting device includes the hydraulic power transmission device for performing the power transmission between the driving source and the automatic speed change mechanism via a fluid, and the clutch is a lockup clutch. Thus, the circulation pressure varies significantly, especially in the state in which large differential rotation is generated in the hydraulic power transmission device. However, even if the circulation pressure varies significantly, the difference between the circulation pressure and the working pressure can always be maintained at an intended value, whereby engagement/disengagement control and slip control of the clutch can be accurately performed.
According to the present invention of claim 3, the circulation pressure is introduced into the second feedback oil chamber from one of the circulation pressure supply port and the circulation pressure discharge port that is located closer to the clutch. Thus, a variation in the circulation pressure can be more accurately transmitted to the second feedback oil chamber, and the difference between the circulation pressure and the working pressure can be more accurately maintained at an intended value, whereby engagement/disengagement control and slip control of the clutch can be accurately performed.
According to the present invention of claim 4, the spool is separated and formed into the first spool that is slidably supported by the main sleeve, and the second spool that is slidably supported by the sub sleeve. Thus, displacement of the centers due to a fitting error, a product error, or the like between the main sleeve and the sub sleeve can be absorbed by the separated portion therebetween, whereby especially the sealing capability between the sub sleeve and the second spool can be satisfactorily ensured. Thus, the length of the spool portion of the pressure-regulating solenoid valve in the axial direction can be reduced, which can contribute to implementation of a more compact hydraulic control device of the automatic transmission.
A first embodiment of the present invention will be described below with reference to
First, the general structure of an automatic transmission and a vehicle drive system to which a hydraulic control device 11 of an automatic transmission of the first embodiment can be applied will be described with reference to
The lockup clutch (a clutch) 3 includes a piston 3a positioned so as to be movable in the axial direction, and a friction material 3b provided on the outer periphery of the piston 3a. The piston 3a is placed so as to separate an oil-tight space 2a from an oil-tight space 2b, and is drivingly moved to and away from the front cover 2A by the differential pressure between the space 2a and the space 2b. That is, as the oil pressure in the space 2b increases, the friction material 3b is separated from the inner side surface of the front cover 2A, and is disengagement-controlled. As the oil pressure in the space 2a increases, the friction material 3b is pressed against the inner side surface of the front cover 2A, and is slip-controlled and engagement-controlled, whereby the lockup clutch 3 is engaged. Thus, when the lockup clutch 3 is engaged, the front cover 2A is directly engaged with the input shaft of the automatic speed change mechanism 40. That is, the torque converter 4 is locked up.
The automatic speed change mechanism 40 is hydraulically controlled by the hydraulic control device 11 to perform engagement/disengagement control of, e.g., friction engagement elements (clutches and brakes), not shown, thereby changing the speed ratio, namely shifting rotation of the input shaft 40a to output the shifted speed from an output shaft 40b. The output shaft 40b is connected to a differential unit 45 via a propeller shaft or the like, and is structured to transmit driving rotation to right and left driving wheels 50r, 50l, respectively.
The hydraulic circuit structure in the hydraulic control device 11 of the automatic transmission will be described in detail below. As shown in
Note that the hydraulic control device 11 of the automatic transmission includes various valves, oil passages, and the like for supplying oil pressure to hydraulic servos of the clutches and brakes of the speed change mechanism 40, in addition to the parts shown in
Reference character PSLT in
As shown in
The primary regulator valve 6 includes a spool 6p, and a spring 6s for biasing the spool 6p upward in the drawing, and also includes an oil chamber 6a located above the spool 6p, an oil chamber 6b located below the spool 6p, a pressure-regulating port 6c, a discharge port 6d, and a back pressure output port 6e. The SLT pressure PSLT is input from the linear solenoid valve SLT to the oil chamber 6b via an oil passages i1, and the line pressure PL, which will be described in detail later, is input to the oil chamber 6a via the oil passages a3, a4 as a feedback pressure.
The spool 6p of the primary regulator valve 6 is subjected to the biasing force of the spring 6s and the SLT pressure PSLT against the feedback pressure. That is, the position of the spool 6p is controlled mainly by the magnitude of the SLT pressure PSLT. When the spool 6p is located on the lower side in the drawing, the pressure-regulating port 6c communicates with the discharge port 6d. As the spool 6p is controlled to move to the upper side in the drawing based on the SLT pressure PSLT, the amount of communication (the throttle amount) between the pressure-regulating port 6c and the discharge port 6d is accordingly reduced (disconnected), while the amount of communication (the throttle amount) between the pressure-regulating port 6c and the back pressure output port 6e is increased accordingly. That is, the spool 6p is controlled to move upward according to the magnitude of the SLT pressure PSLT that is input to the oil chamber 6b, and the amount of oil pressure that is discharged from the discharge port 6d is adjusted, whereby an oil pressure of the pressure-regulating port 6c is regulated. Thus, oil pressures of the oil passages a1, a2, a3, a4, and a5 are regulated as the line pressure PL according to the throttle opening.
The line pressure PL is supplied to the modulator valve 7 via the oil passage a5. The modulator valve 7 has a spool 7p, a spring 7s for biasing the spool 7p upward in the drawing, an input port 7a to which the line pressure PL is input via the oil passage a5, an output port 7b, and a feedback oil chamber 7c. If the line pressure PL is equal to or less than a predetermined value, the modulator valve 7 outputs the oil pressure as it is from the output port 7b as the circulation pressure PCIR. If the line pressure PL is equal to or higher than the predetermined value, a feedback pressure, which is input from the output port 7b to the feedback oil chamber 7c via oil passages c1, c2, overcomes the spring 7s, and the amount of communication (the throttle amount) between the input port 7a and the output port 7b is reduced, and an oil pressure regulated to a fixed value is output as the circulation pressure PCIR.
Note that the line pressure PL is supplied not only to the modulator valve 7, but also to a manual shift valve, various solenoid valves, and the like, not shown. In, e.g., stepped automatic transmissions, the line pressure PL is eventually supplied to hydraulic servos of clutches and brakes to establish a shift speed. In, e.g., belt-type continuously variable transmissions, the line pressure PL is supplied to hydraulic servos of forward/rearward switch clutches and brakes, and the like. Namely, the line pressure PL is used in each part as a source pressure in hydraulic control of the automatic transmission.
The lockup relay valve 8 includes a spool 8p, and a spring 8s for biasing the spool 8p upward in the drawing, and includes an oil chamber 8a located above the spool 8p, a port 8b, an input port 8c, a port 8d, an input port 8e, an input port 8f, an output port 8g, and an input port 8h.
An output port 12c of a spool portion 121 of the linear solenoid valve 101 is connected to the oil chamber 8a via oil passages el, e3, e4. When a working pressure PAPP is output from the linear solenoid valve 101, the working pressure PAPP is input to the oil chamber 8a. That is, in the state in which no working pressure PAPP is output from the linear solenoid valve 101, the lockup relay valve 8 is located at a position shown in the left half in the drawing (hereinafter referred to as the “left-half position”). In the state in which the working pressure PAPP having a predetermined value or more is output from the linear solenoid valve 101, the lockup relay valve 8 overcomes the biasing force of the spring 8s, and is located at a position shown in the right half in the drawing (hereinafter referred to as the “right-half position”). That is, the lockup relay valve 8 is switched based on the input state of the working pressure PAPP.
If the spool 8p of the lockup relay valve 8 is located at the left-half position, the input port 8c communicates with the port 8d, and the input port 8e communicates with the output port 8g. If the spool 8p is located at the right-half position, the input port 8c communicates with the port 8b, the input port 8e communicates with the port 8d, and the input port 8h communicates with the output port 8g.
That is, if the spool 8p of the lockup relay valve 8 is located at the left-half position, the circulation pressure PCIR, which is output from the modulator valve 7, is output from the port 8d to an oil passage f1 via an oil passage c3 and the input port 8c, and is supplied from a lockup off port (L-UP OFF port) 2c of the starting device 2 into the starting device 2. The circulation pressure PCIR supplied into the starting device 2 is discharged from a lockup on port (L-UP ON port) 2d to an oil passage d2, is output from the output port 8g to an oil passage g1 via oil passages d3, d4 and the input port 8f, and is supplied to the oil cooler 15. Oil supplied to the oil cooler 15 is cooled by the oil cooler 15, and is then returned to the oil pan, not shown, so as to be sucked again by the oil pump 5.
Note that at this time, the circulation pressure PCIR discharged to the oil passage d2 is supplied also to a second feedback oil chamber 12a of the linear solenoid valve 101, which will be described later, via the oil passage d3 and an oil passage d5. However, since the linear solenoid valve 101 is not in a driven state, the circulation pressure PCIR does not affect the working pressure PAPP that will be described later.
The linear solenoid valve 101 is roughly formed by a solenoid portion 11 and the spool portion 121. The solenoid portion 11 includes a coil 11a for generating a magnetic field based on a current from a terminal 11t to which wirings are connected, a core member 11c for converging the magnetic field of the coil, a plunger 11b that is drawn downward in the drawing by the magnetic field from the core member 11c, and a shaft 11d that is drivingly pressed downward in the drawing by the plunger 11b.
The spool portion 121 includes a spool 12p that is drivingly pressed downward in the drawing by the shaft 11d, and a spring 12s for biasing the spool 12p upward in the drawing, and has the second feedback oil chamber 12a, the output port 12c, an input port 12d, and a first feedback oil chamber 12b sequentially from above in the drawing. The spool 12p is formed so that a part of the spool 12p located above the second feedback oil chamber 12a, and a part of the spool 12p located below the first feedback oil chamber 12b have a small land diameter, and a part of the spool 12p located between the second feedback oil chamber 12a and the first feedback oil chamber 12b has a land diameter larger than the small land diameter.
That is, as shown in
As shown in
When the working pressure PAPP is output from the linear solenoid valve 101 to the oil passage e1, and the working pressure PAPP is increased to a predetermined value or more, the spool 8p of the lockup relay valve 8 is switched to the right-half position by the working pressure PAPP that is input to the oil chamber 8a via the oil passages e3, e4. When the spool 8p of the lockup relay valve 8 is located at the right-half position, the circulation pressure PCIR that is output from the modulator valve 7 is output from the port 8b to an oil passage dl and the oil passage d2 via the oil passage c3 and the input port 8c, and is supplied from the lockup on port 2d of the starting device 2 into the starting device 2. The working pressure PAPP that is input to the input port 8e via the oil passages e1, e3 and an oil passage e5 is output from the port 8d to the oil passage f1, and is supplied from the lockup off port 2c into the starting device 2.
Thus, due to the difference between the circulation pressure PCIR in the space 2a and the working pressure PAPP in the space 2b in the starting device 2, that is, if the circulation pressure PCIR is larger than the working pressure PAPP, the piston 3a is drivingly pressed against the front cover 2A, and the friction material 3b is pressed against the inner side surface of the front cover 2A and is slip-controlled and engagement-controlled, whereby the lockup clutch 3 is engaged.
Note that when the lockup clutch 3 is in the engaged state, the circulation pressure PCIR is not discharged from the starting device 2, but the back pressure of the line pressure PL which is output from the back pressure output port 6e of the primary regulator valve 6 is input to the input port 8h of the lockup relay valve 8 via an oil passage b1, is output from the output port 8g to the oil passage g1, and is supplied to the oil cooler 15. Similarly, oil supplied to the oil cooler 15 is cooled by the oil cooler 15, and is then returned to the oil pan, not shown, so as to be sucked again by the oil pump 5.
In the hydraulic control device 11 of the automatic transmission, when the lockup clutch 3 is in the engaged state, the circulation pressure PCIR that is output to the oil passage d1 is input to the second feedback oil chamber 12a of the linear solenoid valve 101 via the oil passages d3, d5, and the working pressure PAPP that is output from the output port 12c of the linear solenoid valve 101 is input to the first feedback oil chamber 12b via the oil passages e1, e2 so as to provide feedback action in the direction opposite to the first feedback oil chamber 12b.
Thus, as shown in
(A1−A2)·PAPP+FSP=(A1−A2)·PCIR+FSOL (2)
This expression can be rewritten as follows.
P
APP
=P
CIR+(FSOL−FSP)/(A1−A2) (3)
Thus, the following expression can be obtained.
P
CIR
−P
APP=−(FSOL−FSP)/(A1−A2)=Pd (4)
where “FSP” represents a biasing force of the spring 12s, and “FSOL” represents a driving force of the shaft 11d, and “A1−A2” represents a pressure-receiving area.
Accordingly, in the state in which the driving force FSOL of the shaft 11d having a constant value is output, the pressure-receiving area “A1−A2” and the biasing force FSP of the spring are also constant, and thus, the relation between the working pressure PAPP and the circulation pressure PCIR is such that there is a constant difference Pd between the working pressure PAPP and the circulation pressure PCIR. That is, by setting the pressure-receiving area “A1−A2” of the first feedback oil chamber 12b and the pressure-receiving area “A1−A2” of the second feedback oil chamber 12a equal to each other, an oil pressure acting force of the working pressure PAPP of the first feedback oil chamber 12b and that of the circulation pressure PCIR of the second feedback oil chamber 12a are set equal to each other with respect to the spool 12p.
Thus, as shown in
As described above, the hydraulic control device 11 of the automatic transmission is structured so that the oil pressure acting force of the working pressure PAPP of the first feedback oil chamber 12b and that of the circulation pressure PCIR of the second feedback oil chamber 12a are set equal to each other with respect to the spool 12p of the spool portion 121 of the solenoid valve 101. Thus, even if the circulation pressure PCIR varies, the difference Pd between the circulation pressure PCIR and the working pressure PAPP can always be maintained at the intended value, whereby engagement/disengagement control and slip control of the clutch can be accurately performed.
Specifically, since the pressure-receiving area “A1−A2” of the first feedback oil chamber 12b and the pressure-receiving area “A1−A2” of the second feedback oil chamber 12a are set equal to each other in the spool 12p, the oil pressure acting force of the working pressure PAPP of the first feedback oil chamber 12b and that of the circulation pressure PCIR of the second feedback oil chamber 12a can be equal to each other.
Moreover, the starting device 2 includes the torque converter 4 that transmits power between the engine EG and the automatic speed change mechanism 40 via a fluid, and the clutch is the lockup clutch 3 that can lock up the torque converter 4. Thus, the circulation pressure PCIR varies significantly, especially in the state in which large differential rotation is generated in the torque converter 4. However, even if the circulation pressure PCIR varies significantly, the difference Pd between the circulation pressure PCIR and the working pressure PAPP can always be maintained at the intended value, whereby engagement/disengagement control and slip control of the lockup clutch 3 can be accurately performed.
A second embodiment, which is partially modified from the first embodiment, will be described below with reference to
A hydraulic control device 12 of an automatic transmission according to the second embodiment is modified from the hydraulic control device 11 of the automatic transmission according to the first embodiment in the structure of a starting device 22 and a portion for supplying a circulation pressure PCIR.
That is, as shown in
A lockup clutch (a clutch) 23 includes a support member 23a that is placed so as to be movable in the axial direction, and a plurality of friction plates 23b that are supported by the support member 23a. The friction plates 23b are engagement/disengagement controlled and slip-controlled by the difference in pressure between the space 22a and a space 22b. That is, if the working pressure PAPP on the space 22b side is lower than the circulation pressure Pm on the space 22a side, the friction plates 23b are disengagement-controlled. If the working pressure PAPP on the space 22a side is higher than the circulation pressure PCIR in the space 22a, the friction plates 23b are slip-controlled and engagement-controlled, whereby the lockup clutch 23 is engaged. When the lockup clutch 23 is engaged, a front cover 2A is directly engaged with an input shaft of an automatic speed change mechanism 40. That is, the torque converter 4 is locked up.
In the second embodiment, the back pressure of a line pressure PL which is output from a back pressure output port 6e of a primary regulator valve (a circulation pressure supply portion) 6 is input to a modulator valve 17 via oil passages b1, b2. The modulator valve (the circulation pressure supply portion) 17 has a spool 17p, a spring 17s for biasing the spool 17p upward in the drawing, an input port 17a through which the back pressure of the line pressure PL is input via the oil passage b2, an output port 17b, and a feedback oil chamber 17c. If the back pressure of the line pressure PL is equal to or less than a predetermined value, the modulator valve 17 outputs the oil pressure as it is from the output port 17b as the circulation pressure PCIR. If the back pressure of the line pressure PL is equal to or higher than the predetermined value, a feedback pressure, which is input from the output port 17b to the feedback oil chamber 17c via oil passages c1, c2, overcomes the spring 17s, whereby the communication amount (the throttle amount) between the input port 17a and the output port 17b is reduced, and an oil pressure regulated to a fixed value is output as the circulation pressure PCIR.
Then, the circulation pressure PCIR using the back pressure of the line pressure PL is input to the input port 22d of the starting device 22 via an oil passage c3 and the oil passage c4, and is also input to a second feedback oil chamber 12a of a linear solenoid valve 102 via an oil passage c5 (a circulation pressure introducing oil passage).
Note that the back pressure of the line pressure PL which is output from the back pressure output port 6e of the primary regulator valve 6 is supplied to an oil cooler 15 via the oil passage b1 and an oil passage b3. Oil supplied to the oil cooler 15 is cooled by the oil cooler 15, and is then returned to an oil pan, not shown, so as to be sucked again by an oil pump 5.
The hydraulic control device 12 of the automatic transmission of the second embodiment having the above structure is structured so that the oil pressure acting force of the working pressure PAPP of the first feedback oil chamber 12b and that of the circulation pressure PCIR of the second feedback oil chamber 12a are equal to each other with respect to the spool 12p of the spool portion 122 of the solenoid valve 102. Thus, even if the circulation pressure PCIR varies, the difference Pd between the circulation pressure PCIR and the working pressure PAPP can always be maintained at an intended value, whereby engagement/disengagement control and slip control of the clutch can be accurately performed.
In particular, in the hydraulic control device 12 of the automatic transmission according to the second embodiment, the circulation pressure PCIR is introduced into the second feedback oil chamber 12a from the oil passage c4, which is connected to the input port 22d located closer to the lockup clutch 23 out of the input port 22d and the discharge port 22e of the starting device 22, via the oil passage c5. Thus, for example, an oil pressure at a position closer to the lockup clutch 23 can be fed back, as compared to, e.g., the case where the circulation pressure PCIR, which is discharged from the oil passage d1 connected to the discharge port 22e, is introduced into the second feedback oil chamber 12a. Accordingly, a variation in circulation pressure PCIR can be more accurately transmitted to the second feedback oil chamber 12a, and the difference Pd between the circulation pressure PCIR and the working pressure PAPP can be more accurately maintained at the intended value, whereby engagement/disengagement control and slip control of the lockup clutch 23 can be accurately performed.
Note that since the structures, functions, and effects of the parts other than those described above are similar to the first embodiment, description thereof will be omitted.
A third embodiment, which is partially modified from the first and second embodiments, will be described below with reference to
A hydraulic control device 13 of an automatic transmission according to the third embodiment is modified from the hydraulic control devices 11, 12 of the automatic transmission according to the first and second embodiments in the structure of a starting device 32 and a portion for supplying a circulation pressure PCIR.
That is, as shown in
The starting device 32 of the third embodiment does not include a torque converter, and includes only a starting clutch 33. Thus, when, e.g., starting a vehicle, the starting clutch 33 is slip-controlled and engagement-controlled, whereby transmission of a driving force is achieved while absorbing the differential rotation between an engine EG and an input shaft of an automatic speed change mechanism 40.
The starting clutch (a clutch) 33 includes a support member 33a that is placed so as to be movable in the axial direction, and a plurality of friction plates 33b that are supported by the support member 33a. The friction plates 33b are engagement/disengagement controlled and slip-controlled by the difference in pressure between the space 32a and a space 32b. That is, if the working pressure PAPP on the space 32b side is lower than the circulation pressure PCIR on the space 32a side, the friction plates 33b are disengagement-controlled. If the working pressure PAPP on the space 32a side is higher than the circulation pressure PCIR on the space 32a side, the friction plates 33b are slip-controlled and engagement-controlled, whereby the starting clutch 33 is engaged.
In the third embodiment, the back pressure of a line pressure PL which is output from a back pressure output port 6e of a primary regulator valve (a circulation pressure supply portion) 6 is input to a secondary regulator valve 9 via oil passages b1, b2. The secondary regulator valve (the circulation pressure supply portion) 9 includes a spool 9p, and a spring 9s for biasing the spool 9p upward in the drawing, and also includes an oil chamber 9a located above the spool 9p, an oil chamber 9b located below the spool 9p, a pressure-regulating port 9c, a discharge port 9d, and a back pressure output port 9e. An SLT pressure PSLT is input from the linear solenoid valve SLT, which is described above, to the oil chamber 9b via oil passages i1, i3, and a secondary pressure PSEC, which will be described in detail later, is input to the oil chamber 9a via the oil passages b2, b3, b4 as a feedback pressure. Note that the SLT pressure PSLT is input from the linear solenoid valve SLT to an oil chamber 6b of the primary regulator valve 6 via the oil passage i1 and an oil passage i2.
The spool 9p of the secondary regulator valve 9 is subjected to the biasing force of the spring 9s and the SLT pressure PSLT against the feedback pressure. That is, the position of the spool 9p is controlled mainly by the magnitude of the SLT pressure PSLT. When the spool 9p is located on the lower side in the drawing, the pressure-regulating port 9c communicates with the discharge port 9d. As the spool 9p is controlled to move to the upper side in the drawing based on the SLT pressure PSLT, the amount of communication (the throttle amount) between the pressure-regulating port 9c and the discharge port 9d is accordingly reduced (disconnected), and the amount of communication (the throttle amount) between the pressure-regulating port 9c and the back pressure output port 9e is increased accordingly. That is, the spool 9p is controlled to move upward according to the magnitude of the SLT pressure PSLT that is input to the oil chamber 9b, and the amount of oil pressure that is discharged from the discharge port 9c is adjusted, whereby an oil pressure of the pressure-regulating port 9d is regulated. Thus, oil pressures of the oil passages b1, b2, b3, b4, b5 are regulated as the secondary pressure PSEC according to the throttle opening.
The secondary pressure PSEC regulated by the secondary regulator valve 9 is input to a modulator valve 27. The modulator valve (a circulation pressure supply portion) 27 has a spool 27p, a spring 27s for biasing the spool 27p upward in the drawing, an input port 27a to which the secondary pressure PSEC is input via the oil passage b5, an output port 27b, and a feedback oil chamber 27c. If the secondary pressure PSEC is equal to or less than a predetermined value, the modulator valve 27 outputs the oil pressure as it is from the output port 27b as the circulation pressure PCIR. If the secondary pressure PSEC is equal to or higher than the predetermined value, a feedback pressure, which is input from the output port 27b to the feedback oil chamber 27c via oil passages c1, c2, overcomes the spring 27s, and the amount of communication (the throttle amount) between the input port 27a and the output port 27b is reduced, and an oil pressure regulated to a fixed value is output as the circulation pressure PCIR.
The circulation pressure PCIR using the secondary pressure PSEC is input to the input port 32d of the starting device 32 via an oil passage c3 and the oil passage c4, and is also input to a second feedback oil chamber 12a of a linear solenoid valve 103 via an oil passage c5 (a circulation pressure introducing oil passage).
Note that the back pressure of the secondary pressure PSEC that is output from the back pressure output port 9e of the secondary regulator valve 9 is supplied to an oil cooler 15 via an oil passage g1. Oil supplied to the oil cooler 15 is cooled by the oil cooler 15, and is then returned to an oil pan, not shown, so as to be sucked again by an oil pump 5.
The hydraulic control device 13 of the automatic transmission of the third embodiment having the above structure is structured so that the oil pressure acting force of the working pressure PAPP of a first feedback oil chamber 12b and that of the circulation pressure PCIR of the second feedback oil chamber 12a are equal to each other with respect to the spool 12p of the spool portion 123 of the solenoid valve 103. Thus, even if the circulation pressure PCIR varies, the difference Pd between the circulation pressure PCIR and the working pressure PAPP can always be maintained at an intended value, whereby engagement/disengagement control and slip control of the clutch can be accurately performed.
In particular, in the hydraulic control device 13 of the automatic transmission according to the third embodiment, the circulation pressure PCIR is introduced into the second feedback oil chamber 12a from the oil passage c4, which is connected to the input port 32d located closer to the starting clutch 33 out of the input port 32d and the discharge port 32e of the starting device 32, via the oil passage c5. Thus, for example, an oil pressure at a position closer to the starting clutch 33 can be fed back, as compared to, e.g., the case where the circulation pressure PCIR, which is discharged from the oil passage d1 connected to the discharge port 32e, is introduced into the second feedback oil chamber 12a. Accordingly, a variation in circulation pressure PCIR can be more accurately transmitted to the second feedback oil chamber 12a, and the difference Pd between the circulation pressure PCIR and the working pressure PAPP can be more accurately maintained at the intended value, whereby engagement/disengagement control and slip control of the starting clutch 33 can be accurately performed.
Note that since the structures, functions, and effects of the parts other than those described above are similar to the first and second embodiments, description thereof will be omitted.
A fourth embodiment, which is partially modified from the first to third embodiments, will be described with reference to
The fourth embodiment is partially modified from the hydraulic control device 1 of the automatic transmission according to the first to third embodiments in the structure of the spool portion 12 of the linear solenoid valve 10.
As described above, in the linear solenoid valve 10 of the hydraulic control device 1 of the automatic transmission, the pressure-receiving area of the second feedback oil chamber 12a and the pressure-receiving area of the first feedback oil chamber 12b are set equal to each other. Accordingly, the spool 12p needs to be formed so as to have a thin (small) land diameter in one end (a portion the slides with respect to a main sleeve 12SA), have a thick (large) land diameter in an intermediate portion, and have a thin (small) land diameter in the other end. Thus, in the structures of the first to third embodiments (see
However, in the structures of the first to third embodiments (see
Thus, in a spool portion 124 of a linear solenoid valve 104 of the fourth embodiment, as shown in
More specifically, as shown in
The first spool 12p1 is structured so that the second feedback oil chamber 12a is formed by the difference in pressure-receiving area “A1−A2” which is produced by the difference in diameter between the small-diameter land portion 12pr1 and the large-diameter land portion 12pr2, and the communication state between an output port 12c and an input port 12d, and the communication state between the output port 12c and a drain port EX are adjusted by the position of the gap between the large-diameter land portion 12pr2 and the large-diameter land portion 12pr3 in the axial direction, namely by the position of the first spool 12p1 in the axial direction. Each land portion 12pr1, 12pr2, 12pr3 (that is, at least one end) of the first spool 12p1 is slidably supported on the inner periphery of the main sleeve 12SA.
On the other hand, the second spool 12p2 has its upper end in the drawing in contact with the lower end of the first spool 12p1 in the drawing, and is completely separated from the first spool 12p1. The first feedback oil chamber 12b is formed by the difference in pressure-receiving area “A1−A2” which is produced by the difference in diameter between the large-diameter land portion 12pr4 and the small-diameter land portion 12pr5. The sub sleeve 12SB is interposed between the main sleeve 12SA and the land portions 12pr4, 12pr5 of the second spool 12p2 so as to fill the gap therebetween, and each land portion 12pr4, 12pr5 (that is, the other end) of the second spool 12p2 is slidably supported on the inner periphery of the sub sleeve 12SB.
Note that a drain port EX is formed in the portion (that is, the separated portion) where the lower end of the first spool 12p1 in the drawing contacts the upper end of the second spool 12p2 in the drawing, so that the drive states of the first spool 12p1 and the second spool 12p2 are not affected. The lower end of the sub sleeve 12SB in the drawing serves as a cap portion 12c, and the cap portion 12c is screwed in the main sleeve 12SA, and contains a spring 12s in a contracted state between the cap portion 12c and the second spool 12p2.
The spool portion 124 of the linear solenoid valve 104 structured as described above is assembled by attaching the main sleeve 12SA to a solenoid portion 11 by caulking or the like, sequentially inserting the first spool 12p1 and the second spool 12p2 into a hollow portion of the main sleeve 12SA, fittingly inserting the sub sleeve 12SB around the second spool 12p2, and screwing the cap portion 12c in the main sleeve 12SA with the spring 12s inserted therein.
As described above, according to the linear solenoid valve 104 of the fourth embodiment, the spool is separated and formed into the first spool 12p1 that is slidably supported by the main sleeve 12SA, and the second spool 12p2 that is slidably supported by the sub sleeve 12SB. Thus, the displacement of the centers due to a fitting error, a product error, or the like between the main sleeve 12SA and the sub sleeve 12SB can be absorbed by the separated portion between the first spool 12p1 and the second spool 12p2, whereby especially the sealing capability between the sub sleeve 12SB and the second spool 12p2 can be satisfactorily ensured. Thus, even if the drain port EX needs to be additionally provided in the separate portion between the first spool 12p1 and the second spool 12p2, the overall length of the spool portion 124 of the linear solenoid valve 104 in the axial direction can be reduced, which can contribute to implementation of a more compact hydraulic control device 1 of the automatic transmission.
Note that since the structures, functions, and effects of the parts other than those described above are similar to the first to third embodiments, description thereof will be omitted.
A fifth embodiment, which is partially modified from the fourth embodiment, will be described below with reference to
A spool portion 125 of a solenoid valve 105 of the fifth embodiment is modified from the spool portion 124 of the solenoid valve 104 of the fourth embodiment in the structures of the second spool 12p2 and the sub sleeve 12SB and the position where the spring 12s is placed.
More specifically, as shown in
In the spool portion 125 of the present embodiment, the outer diameter of the second spool 12p2 is set so that the cross-sectional area of the second spool 12p2 is equal to the difference in pressure-receiving area “A1−A2” between the small-diameter land portion 12pr1 and the large-diameter land portion 12pr2 of the first spool 12p1, namely so that an oil pressure acting area of the first feedback oil chamber 12b and an oil pressure acting area of the second feedback oil chamber 12a are set equal to each other. In the spool portion 125, the lower end of the sub sleeve 12SB in the drawing serves as a cap portion 12c, and the cap portion 12c is screwed in the main sleeve 12SA, and contains a spring 12s in a compressed state between the lower end of the first spool 12p1 in the drawing and the upper end of the sub sleeve 12SB in the drawing (that is, in the separated portion between the first spool 12p1 and the second spool 12p2).
The spool portion 125 of the linear solenoid valve 105 structured as described above is assembled by attaching the main sleeve 12SA to a solenoid portion 11 by caulking or the like, sequentially inserting the first spool 12p1 and the spring 12s into a hollow portion of the main sleeve 12SA, and inserting the sub sleeve 12SB, which has the second spool 12p2 inserted therein, into the main sleeve 12SA by screwing the cap portion 12c in the main sleeve 12SA.
As described above, according to the spool portion 125 of the linear solenoid valve 105 of the fifth embodiment, no land portion need be provided in the second spool 12p2, whereby the second spool 12p2 can be shortened, and thus the length of the spool portion 124 in the axial direction can be reduced. Moreover, since the spring 12s is placed in the separated portion between the first spool 12p1 and the second spool 12p2, a drain port EX provided in the separated portion between the first spool 12p1 and the second spool 12p2 can be used also as a drain port EX for draining an oil pressure in a chamber in which the spring 12s is provided (see
Note that since the structures, functions, and effects of the parts other than those described above are similar to the first to fourth embodiments, description thereof will be omitted.
Note that the first to third embodiments are described with respect to examples in which the hydraulic control device 1 is used for the automatic speed change mechanism 40 of the structure in which the engine EG is mounted in the longitudinal direction with respect to the traveling direction of the vehicle as in the front-engine, rear-wheel drive (FR) type, as shown in
The embodiments of the present invention are described with respect to examples in which an internal combustion engine is used as a driving source. However, it is to be understood that the hydraulic control device of the automatic transmission of the present invention may also be applied to hybrid vehicles provided with a motor generator.
The hydraulic control device of the automatic transmission of the present invention can be used as a hydraulic control device of automatic transmissions that are mounted on passenger cars, trucks, or the like, and is especially preferable when used in automatic transmissions that are required to accurately perform engagement/disengagement control and slip control of a clutch for enabling and disabling power transmission between a driving source and an automatic speed change mechanism.
1
1, 12, 13 hydraulic control device of automatic transmission
2 starting device
3 clutch, lockup clutch
4 hydraulic power transmission device (torque converter)
6 circulation pressure supply portion (primary regulator valve)
7 circulation pressure supply portion (modulator valve)
9 circulation pressure supply portion (secondary regulator valve)
10
1 to 105 pressure-regulating solenoid valve (linear solenoid valve)
11 solenoid portion
12
1 to 125 spool portion
12SA main sleeve
12SB sub sleeve
12
a second feedback oil chamber
12
b first feedback oil chamber
12
p spool
12
p
1 first spool
12
p
2 second spool
12
s spring
17 circulation pressure supply portion (modulator valve)
22 starting device
22
c working pressure supply port (lockup on port)
22
d circulation pressure supply port (input port)
22
e circulation pressure discharge port (discharge port)
23 clutch, lockup clutch
27 circulation pressure supply portion (modulator valve)
32 starting device
32
c working pressure supply port (lockup on port)
32
d circulation pressure supply port (input port)
32
e circulation pressure discharge port (discharge port)
33 clutch (starting clutch)
40 automatic speed change mechanism
AT automatic transmission
EG driving source (engine)
PCIR circulation pressure
PAPP working pressure
c4 circulation pressure supply oil passage (oil passage)
c5 circulation pressure introducing oil passage (oil passage)
d1 circulation pressure discharge oil passage (oil passage)
e3 circulation pressure supply oil passage (oil passage)
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-224211 | Sep 2009 | JP | national |
| 2010-060570 | Mar 2010 | JP | national |
