Automatic gear transmission
First Claim
1. A gear-shift mechanism for a gear transmission including a changeover shaft mounted within a housing of the gear transmission for both axial and rotary movements to be axially shifted from a neutral position to a forward or reverse position in selecting operation and to be rotated at its shifted position in shifting operation, a shift-and-select lever fixed to an intermediate portion of the changeover shaft for axial and rotary movements therewith, an interlock member rotatably mounted in place on the changeover shaft and having a pair of interlock arms located at the opposite sides of the shift-and-select lever, detent means for restricting rotary movement of the interlock member and for permitting axial movement of the interlock member, a plurality of fork shafts mounted in parallel within the housing for axial movement in a shift direction perpendicular to the changeover shaft;
- a plurality of shift forks mounted on the fork shafts to be selectively engaged with each sleeve of a plurality of changeover mechanisms for selectively establishing a plurality of change-speed gear trains in the gear transmission, a plurality of shift heads mounted on the fork shafts to be selectively engaged with the shift-and-select lever at their neutral positions, a first actuator operatively connected to the changeover shaft for effecting rotary movement of the changeover shaft when activated under control of an electric controller, a shift-stroke sensor for detecting the operation of the first actuator, a second actuator operatively connected to the changeover shaft for effecting axial movement of the changeover shaft when activated under control of the electric controller, and a selection-stroke sensor for detecting the operation of the second actuator,wherein said shift-and-select lever is loaded by resilient means assembled therewith toward an initial position in which said shift-and-select lever is brought into engagement with one of said shift heads for establishing a low speed gear train, and wherein in the occurrence of a failure in at least one of said selection-stroke sensor and said shift-stroke sensor, said second actuator is deactivated under control of said electric controller to permit free movement of said changeover shaft in an axial direction and said first actuator is activated under control of said electric controller to effect rotary movement of said changeover shaft so that said shift-and-select lever is moved to the initial position under the load of said resilient means and brought into engagement with the one of said shift heads to establish the low speed gear train.
1 Assignment
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Accused Products
Abstract
A gear-shift mechanism for a gear transmission in which a shift-and-select lever on a changeover shaft is loaded by a compression spring assembled therewith toward an initial position where the shift-and-select lever is brought into engagement with a shift head for 1st-2nd speeds for selectively establishing first or second speed gear train, and in which in the occurrence of a failure in any one of a selection-stroke sensor and a shift-stroke sensor, a second actuator is deactivated under control of an electric controller to permit free movement of the changeover shaft in an axial direction and a second actuator is activated under control of the electric controller to effect rotary movement of the changeover shaft so that the shift-and-select lever is moved to the initial position under the load of the compression spring and brought into engagement with the shift head to establish first or second speed gear train.
21 Citations
4 Claims
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1. A gear-shift mechanism for a gear transmission including a changeover shaft mounted within a housing of the gear transmission for both axial and rotary movements to be axially shifted from a neutral position to a forward or reverse position in selecting operation and to be rotated at its shifted position in shifting operation, a shift-and-select lever fixed to an intermediate portion of the changeover shaft for axial and rotary movements therewith, an interlock member rotatably mounted in place on the changeover shaft and having a pair of interlock arms located at the opposite sides of the shift-and-select lever, detent means for restricting rotary movement of the interlock member and for permitting axial movement of the interlock member, a plurality of fork shafts mounted in parallel within the housing for axial movement in a shift direction perpendicular to the changeover shaft;
- a plurality of shift forks mounted on the fork shafts to be selectively engaged with each sleeve of a plurality of changeover mechanisms for selectively establishing a plurality of change-speed gear trains in the gear transmission, a plurality of shift heads mounted on the fork shafts to be selectively engaged with the shift-and-select lever at their neutral positions, a first actuator operatively connected to the changeover shaft for effecting rotary movement of the changeover shaft when activated under control of an electric controller, a shift-stroke sensor for detecting the operation of the first actuator, a second actuator operatively connected to the changeover shaft for effecting axial movement of the changeover shaft when activated under control of the electric controller, and a selection-stroke sensor for detecting the operation of the second actuator,
wherein said shift-and-select lever is loaded by resilient means assembled therewith toward an initial position in which said shift-and-select lever is brought into engagement with one of said shift heads for establishing a low speed gear train, and wherein in the occurrence of a failure in at least one of said selection-stroke sensor and said shift-stroke sensor, said second actuator is deactivated under control of said electric controller to permit free movement of said changeover shaft in an axial direction and said first actuator is activated under control of said electric controller to effect rotary movement of said changeover shaft so that said shift-and-select lever is moved to the initial position under the load of said resilient means and brought into engagement with the one of said shift heads to establish the low speed gear train. - View Dependent Claims (2, 4)
- a plurality of shift forks mounted on the fork shafts to be selectively engaged with each sleeve of a plurality of changeover mechanisms for selectively establishing a plurality of change-speed gear trains in the gear transmission, a plurality of shift heads mounted on the fork shafts to be selectively engaged with the shift-and-select lever at their neutral positions, a first actuator operatively connected to the changeover shaft for effecting rotary movement of the changeover shaft when activated under control of an electric controller, a shift-stroke sensor for detecting the operation of the first actuator, a second actuator operatively connected to the changeover shaft for effecting axial movement of the changeover shaft when activated under control of the electric controller, and a selection-stroke sensor for detecting the operation of the second actuator,
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3. A gear-shift mechanism for a gear transmission including a changeover shaft mounted with a housing of the gear transmission for both axial and rotary movements to be axially shifted from a neutral position to a forward or reverse position in selecting operation and to be rotated at its shifted position in shifting operation, a shift-and-select lever fixed to an intermediate portion of the changeover shaft for axial and rotary movements therewith, an interlock member rotatably mounted in place on the changeover shaft and having a pair of interlock arms located at the opposite sides of the shift-and-select lever, detent means for restricting rotary movement of the interlock member and for permitting axial movement of the interlock member, a plurality of fork shafts mounted in parallel within the housing for axial movement in a shift direction perpendicular to the changeover shaft, shift forks for 1st-2nd speeds, 3rd-4th speeds and 5th-6th speeds mounted on the fork shafts to be selectively engaged with each sleeve of a plurality of changeover mechanisms for selectively establishing first to sixth speed gear trains in the gear transmission, shift heads for 1st-2nd speeds, 3rd-4th speeds and 5th-6th speeds mounted on the fork shafts to be selectively engaged with the shift-and-select lever at their neutral positions, a first actuator operatively connected to the changeover shaft for effecting rotary movement of the changeover shaft when activated under control of an electric controller, a shift-stroke sensor for detecting the operation of the first actuator, a second actuator operatively connected to the changeover shaft for effecting axial movement of the changeover shaft when activated under control of the electric controller, and a selection-stroke sensor for detecting the operation of the second actuator,
wherein said shift-and-select lever is loaded by resilient means assembled therewith toward an initial position in which said shift-and-select lever is brought into engagement with said shift head for 1st-2nd speeds for selectively establishing first and second speed gear trains, and wherein in the occurrence of a failure in at least one of said selection-stroke sensor and said shift-stroke sensor, said second actuator is deactivated under control of said electric controller to permit free movement of said changeover shaft in an axial direction and said first actuator is activated under control of said electric controller to effect rotary movement of said changeover shaft so that said shift-and-select lever is moved to the initial position under the load of said resilient means and brought into engagement with said shift head for 1st-2nd speeds to establish the first or second speed gear train.
Specification