Shift-by-wire gearshift control apparatus

• US 8,579,763 B2
• Filed: 11/25/2009
• Issued: 11/12/2013
• Est. Priority Date: 11/25/2009
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nakade, Yusuke, Itazu, Naoki
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US13/511,376
• Publication Number:
  US 20120283066A1
• Time in Patent Office: 1,448 Days
• Field of Search: None
• US Class Current: 477/126
• CPC Class Codes: F16H 2061/1204 for malfunction caused by simultaneous engagement of different ratios resulting in transmission lock state or tie-up condition lock state for braking F16H61/0059
• CPC Class Codes: F16H 2061/1232 Bringing the control into a predefined state, e.g. giving priority to particular actuators or gear ratios
• CPC Class Codes: F16H 2061/326 Actuators for range selection, i.e. actuators for controlling the range selector or the manual range valve in the transmission
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/686 with orbital gears

Abstract

In a shift-by-wire gearshift control apparatus, even if a switching anomaly in which switching between forward and reverse gears is not possible has occurred, transmission of driving power to the output shaft 10 can be interrupted as quickly as possible. In the case of the occurrence of a switching anomaly in which switching from a forward gear stage to a reverse gear stage, or vice versa, is not possible, as a path for draining engaging hydraulic pressure supplied to a frictional engagement element (C1 to C4, B1, B2) involved in establishing the current gear stage, the hydraulic control circuit 4 secures an anomaly drain path (91 or 92) that is shorter than a normal drain path (81, 82 or 83) secured by the hydraulic control circuit 4 during normal switching.

Claims

1. A shift-by-wire gearshift control apparatus that, in response to a target range signal output as a result of a driver operation, switches an automatic transmission range, the shift-by-wire gearshift control apparatus comprising:

a gearshift mechanism unit that includes a plurality of frictional engagement elements for establishing the target range and that changes rotation of an input shaft and outputs the rotation to an output shaft;

a hydraulic control circuit that secures a supply path for engaging hydraulic pressure for engaging a necessary frictional engagement element to establish the target range;

an operation unit for outputting a target range signal in response to the driver operation;

a command unit for causing the hydraulic control circuit to supply engaging hydraulic pressure for the necessary frictional engagement element in response to the target range signal; and

a management unit for, in a case of occurrence of a switching anomaly in which switching from a forward travel range to a reverse travel range or switching from the reverse travel range to the forward travel range is not possible, causing the hydraulic control circuit to secure an anomaly drain path that is shorter than a normal drain path that is secured by the hydraulic control circuit during normal switching operation, as a path for draining engaging hydraulic pressure supplied to a frictional engagement element involved in establishing an actual range,

wherein the hydraulic control circuit includes a plurality of solenoid valves for individually supplying engaging hydraulic pressure to the respective frictional engagement elements, a cutoff valve for prevention of tie-up that is provided in a path for supplying engaging hydraulic pressure to a frictional engagement element involved in establishing the forward travel range and that interrupts or permits supply of engaging hydraulic pressure to the frictional engagement element from the solenoid valve as necessary, and a valve for supplying control hydraulic pressure for opening a drain port to the cutoff valve in order to secure the anomaly drain path, and

the management unit sets, as an anomaly drain path secured in the case of the occurrence of the switching anomaly from the forward travel range to the reverse travel range, a path that causes the engaging hydraulic pressure supplied to the frictional engagement element involved in establishing the forward travel range to drain from a drain port of the cutoff valve, and causes the control hydraulic pressure for opening a drain port supplied to the cutoff valve to drain after draining from the anomaly drain path.

2. The shift-by-wire gearshift control apparatus according to claim 1,

wherein in the case of the occurrence of the switching anomaly, the management unit first determines whether or not oil temperature in the hydraulic control circuit is less than a threshold value, and causes the hydraulic control circuit to secure the anomaly drain path if the oil temperature is less than the threshold value, and causes the hydraulic control circuit to secure the normal drain path if the oil temperature is greater than or equal to the threshold value.

3. The shift-by-wire gearshift control apparatus according to claim 1,

wherein the management unit includes an identification unit that identifies a currently established actual range and an anomaly determining unit that determines whether or not the switching anomaly has occurred, and

the anomaly determining unit checks whether or not the target range and the actual range identified by the identification unit match.

4. The shift-by-wire gearshift control apparatus according to claim 1,

wherein the command unit includes a manual valve for supplying the engaging hydraulic pressure to an appropriate frictional engagement element via an appropriate solenoid valve, an actuator for actuating the manual valve, and a control unit for controlling an operation of the solenoid valve and the actuator in response to the target range signal.

5. The shift-by-wire gearshift control apparatus according to claim 1,

wherein the gearshift mechanism unit includes a double pinion type front planetary gear unit that is provided on an upstream side in a power transmission direction and a ravigneaux type rear planetary gear unit that is provided on a downstream side in the power transmission direction, and a carrier of the front planetary gear unit is coupled to the input shaft and a ring gear of the rear planetary gear unit is coupled to the output shaft,

the frictional engagement elements include:

a first clutch for causing a ring gear of the front planetary gear unit and a small-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a second clutch for causing the input shaft and a carrier of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a third clutch for causing the ring gear of the front planetary gear unit and a large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a fourth clutch for causing the carrier of the front planetary gear unit and the large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

an intermediate rotator for integrally coupling the large-diameter sun gear of the rear planetary gear unit, a free side friction plate of the third clutch and a free side friction plate of the fourth clutch;

a first brake for causing the intermediate rotator to be rotatable or non-rotatable; and

a second brake for causing the carrier of the rear planetary gear unit to be rotatable or non-rotatable, and

a first forward gear stage in the forward travel range is established when only the first clutch is engaged, and the reverse travel range is established when the fourth clutch and the second brake are engaged.

9. The shift-by-wire gearshift control apparatus according to claim 2,

wherein the management unit includes an identification unit that identifies a currently established actual range and an anomaly determining unit that determines whether or not the switching anomaly has occurred, and

the anomaly determining unit checks whether or not the target range and the actual range identified by the identification unit match.

10. The shift-by-wire gearshift control apparatus according to claim 2,

wherein the command unit includes a manual valve for supplying the engaging hydraulic pressure to an appropriate frictional engagement element via an appropriate solenoid valve, an actuator for actuating the manual valve, and a control unit for controlling an operation of the solenoid valve and the actuator in response to the target range signal.

11. The shift-by-wire gearshift control apparatus according to claim 3,

wherein the command unit includes a manual valve for supplying the engaging hydraulic pressure to an appropriate frictional engagement element via an appropriate solenoid valve, an actuator for actuating the manual valve, and a control unit for controlling an operation of the solenoid valve and the actuator in response to the target range signal.

12. The shift-by-wire gearshift control apparatus according to claim 2,

wherein the gearshift mechanism unit includes a double pinion type front planetary gear unit that is provided on an upstream side in a power transmission direction and a ravigneaux type rear planetary gear unit that is provided on a downstream side in the power transmission direction, and a carrier of the front planetary gear unit is coupled to the input shaft and a ring gear of the rear planetary gear unit is coupled to the output shaft,

the frictional engagement elements include:

a first clutch for causing a ring gear of the front planetary gear unit and a small-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a second clutch for causing the input shaft and a carrier of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a third clutch for causing the ring gear of the front planetary gear unit and a large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a fourth clutch for causing the carrier of the front planetary gear unit and the large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

an intermediate rotator for integrally coupling the large-diameter sun gear of the rear planetary gear unit, a free side friction plate of the third clutch and a free side friction plate of the fourth clutch;

a first brake for causing the intermediate rotator to be rotatable or non-rotatable; and

a second brake for causing the carrier of the rear planetary gear unit to be rotatable or non-rotatable, and

a first forward gear stage in the forward travel range is established when only the first clutch is engaged, and the reverse travel range is established when the fourth clutch and the second brake are engaged.

13. The shift-by-wire gearshift control apparatus according to claim 3,

wherein the gearshift mechanism unit includes a double pinion type front planetary gear unit that is provided on an upstream side in a power transmission direction and a ravigneaux type rear planetary gear unit that is provided on a downstream side in the power transmission direction, and a carrier of the front planetary gear unit is coupled to the input shaft and a ring gear of the rear planetary gear unit is coupled to the output shaft,

the frictional engagement elements include:

a first clutch for causing a ring gear of the front planetary gear unit and a small-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a second clutch for causing the input shaft and a carrier of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a third clutch for causing the ring gear of the front planetary gear unit and a large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a fourth clutch for causing the carrier of the front planetary gear unit and the large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

an intermediate rotator for integrally coupling the large-diameter sun gear of the rear planetary gear unit, a free side friction plate of the third clutch and a free side friction plate of the fourth clutch;

a first brake for causing the intermediate rotator to be rotatable or non-rotatable; and

a second brake for causing the carrier of the rear planetary gear unit to be rotatable or non-rotatable, and

a first forward gear stage in the forward travel range is established when only the first clutch is engaged, and the reverse travel range is established when the fourth clutch and the second brake are engaged.

14. The shift-by-wire gearshift control apparatus according to claim 4,

wherein the gearshift mechanism unit includes a double pinion type front planetary gear unit that is provided on an upstream side in a power transmission direction and a ravigneaux type rear planetary gear unit that is provided on a downstream side in the power transmission direction, and a carrier of the front planetary gear unit is coupled to the input shaft and a ring gear of the rear planetary gear unit is coupled to the output shaft,

the frictional engagement elements include:

a first clutch for causing a ring gear of the front planetary gear unit and a small-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a second clutch for causing the input shaft and a carrier of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a third clutch for causing the ring gear of the front planetary gear unit and a large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a fourth clutch for causing the carrier of the front planetary gear unit and the large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

an intermediate rotator for integrally coupling the large-diameter sun gear of the rear planetary gear unit, a free side friction plate of the third clutch and a free side friction plate of the fourth clutch;

a first brake for causing the intermediate rotator to be rotatable or non-rotatable; and

a second brake for causing the carrier of the rear planetary gear unit to be rotatable or non-rotatable, and

a first forward gear stage in the forward travel range is established when only the first clutch is engaged, and the reverse travel range is established when the fourth clutch and the second brake are engaged.

6. A shift-by-wire gearshift control apparatus that, in response to a target range signal output as a result of a driver operation, switches an automatic transmission range, the shift-by-wire gearshift control apparatus comprising:

a gearshift mechanism unit that includes a plurality of frictional engagement elements for establishing the target range and that changes rotation of an input shaft and outputs the rotation to an output shaft;

a hydraulic control circuit that secures a supply path for engaging hydraulic pressure for engaging a necessary frictional engagement element to establish the target range;

an operation unit for outputting a target range signal in response to the driver operation; and

a command unit for causing the hydraulic control circuit to supply engaging hydraulic pressure for the necessary frictional engagement element in response to the target range signal;

the gearshift mechanism unit including a double pinion type front planetary gear unit that is provided on an upstream side in a power transmission direction and a ravigneaux type rear planetary gear unit that is provided on a downstream side in the power transmission direction, and a carrier of the front planetary gear unit being coupled to the input shaft and a ring gear of the rear planetary gear unit being coupled to the output shaft,

the frictional engagement elements including;

a first clutch for causing a ring gear of the front planetary gear unit and a small-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a second clutch for causing the input shaft and a carrier of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a third clutch for causing the ring gear of the front planetary gear unit and a large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a fourth clutch for causing the carrier of the front planetary gear unit and the large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

an intermediate rotator for integrally coupling the large-diameter sun gear of the rear planetary gear unit, a free side friction plate of the third clutch and a free side friction plate of the fourth clutch;

a first brake for causing the intermediate rotator to be rotatable or non-rotatable; and

a second brake for causing the carrier of the rear planetary gear unit to be rotatable or non-rotatable,

wherein a first forward gear stage in the forward travel range is established when only the first clutch is engaged, and the reverse travel range is established when the fourth clutch and the second brake are engaged; and

a management unit for, in a case of occurrence of a switching anomaly in which switching from the first forward gear stage in the forward travel range to the reverse travel range or switching from the reverse travel range to the first forward gear stage in the forward travel range is not possible, causing the hydraulic control circuit to secure an anomaly drain path that is shorter than a normal drain path that is secured by the hydraulic control circuit during normal switching operation, as a path for draining engaging hydraulic pressure supplied to a frictional engagement element involved in establishing an actual range,

wherein the hydraulic control circuit includes a plurality of solenoid valves for individually supplying engaging hydraulic pressure to the first to fourth clutches and the first and second brakes, and a cutoff valve for prevention of tie-up that is provided between the first clutch and a solenoid valve for supplying engaging hydraulic pressure thereto and that interrupts or permits supply of engaging hydraulic pressure to the first clutch as necessary, and a valve for supplying control hydraulic pressure for opening a drain port to the cutoff valve in order to secure the anomaly drain path, and

the management unit sets, as an anomaly drain path secured in the case of the occurrence of the switching anomaly from the first forward gear stage in the forward travel range to the reverse travel range, a path that causes the engaging hydraulic pressure supplied to the first clutch to drain from a drain port of the cutoff valve, and causes the control hydraulic pressure for opening a drain port supplied to the cutoff valve to drain after draining from the anomaly drain path.

8. The shift-by-wire gearshift control apparatus according to claim 6,

wherein in the case of the occurrence of the switching anomaly, the management unit first determines whether or not oil temperature in the hydraulic control circuit is less than a threshold value, and causes the hydraulic control circuit to secure the anomaly drain path if the oil

temperature is less than the threshold value, and causes the hydraulic control circuit to secure the normal drain path if the oil temperature is greater than or equal to the threshold value.

7. A shift-by-wire gearshift control apparatus that, in response to a target range signal output as a result of a driver operation, switches an automatic transmission range, the shift-by-wire gearshift control apparatus comprising:

a gearshift mechanism unit that includes a plurality of frictional engagement elements for establishing the target range and that changes rotation of an input shaft and outputs the rotation to an output shaft;

a hydraulic control circuit that secures a supply path for engaging hydraulic pressure for engaging a necessary frictional engagement element to establish the target range;

an operation unit for outputting a target range signal in response to the driver operation; and

a command unit for causing the hydraulic control circuit to supply engaging hydraulic pressure for the necessary frictional engagement element in response to the target range signal;

the gearshift mechanism unit including a double pinion type front planetary gear unit that is provided on an upstream side in a power transmission direction and a ravigneaux type rear planetary gear unit that is provided on a downstream side in the power transmission direction, and a carrier of the front planetary gear unit being coupled to the input shaft and a ring gear of the rear planetary gear unit being coupled to the output shaft,

the frictional engagement elements including;

a first clutch for causing a ring gear of the front planetary gear unit and a small-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a second clutch for causing the input shaft and a carrier of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a third clutch for causing the ring gear of the front planetary gear unit and a large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

a fourth clutch for causing the carrier of the front planetary gear unit and the large-diameter sun gear of the rear planetary gear unit to be capable of integral rotation or relative rotation;

an intermediate rotator for integrally coupling the large-diameter sun gear of the rear planetary gear unit, a free side friction plate of the third clutch and a free side friction plate of the fourth clutch;

a first brake for causing the intermediate rotator to be rotatable or non-rotatable; and

a second brake for causing the carrier of the rear planetary gear unit to be rotatable or non-rotatable,

wherein a first forward gear stage in the forward travel range is established when only the first clutch is engaged, and the reverse travel range is established when the fourth clutch and the second brake are engaged; and

a management unit for, in a case of occurrence of a switching anomaly in which switching from the first forward gear stage in the forward travel range to the reverse travel range or switching from the reverse travel range to the first forward gear stage in the forward travel range is not possible, causing the hydraulic control circuit to secure an anomaly drain path that is shorter than a normal drain path that is secured by the hydraulic control circuit during normal switching operation, as a path for draining engaging hydraulic pressure supplied to a frictional engagement element involved in establishing an actual range,

wherein the hydraulic control circuit includes a plurality of solenoid valves for individually supplying engaging hydraulic pressure to the first to fourth clutches and the first and second brakes, a cutoff valve for prevention of tie-up that is provided between the fourth clutch and a solenoid valve for supplying engaging hydraulic pressure thereto and that interrupts or permits supply of engaging hydraulic pressure to the fourth clutch as necessary, a valve for supplying engaging hydraulic pressure supplied to the second brake to the second brake, a manual valve for supplying the engaging hydraulic pressure to an appropriate frictional engagement element via an appropriate solenoid valve, and a valve for supplying control hydraulic pressure for opening a drain port to the valve for supplying engaging hydraulic pressure to the second brake in order to secure the anomaly drain path,

in the hydraulic control circuit, a distance between the second brake and the valve for supplying engaging hydraulic pressure to the second brake is set shorter than a distance between the second brake and the manual valve, and

the management unit sets, as an anomaly drain path secured in the case of the occurrence of the switching anomaly from the reverse travel range to the first forward gear stage in the forward travel range, a path that causes the engaging hydraulic pressure supplied to the second brake to drain from a drain port of the valve for supplying engaging hydraulic pressure to the second brake and causes the control hydraulic pressure for opening a drain port supplied to the valve for supplying engaging hydraulic pressure to the second brake to drain after draining from the anomaly drain path.

15. The shift-by-wire gearshift control apparatus according to claim 7,

wherein in the case of the occurrence of the switching anomaly, the management unit first determines whether or not oil temperature in the hydraulic control circuit is less than a threshold value, and causes the hydraulic control circuit to secure the anomaly drain path if the oil temperature is less than the threshold value, and causes the hydraulic control circuit to secure the normal drain path if the oil temperature is greater than or equal to the threshold value.