Control system for transmission

Patent metadata

Field	Value
Publication number	US-2016258529-A1
Application number	US-201615050531-A
Country	US
Kind code	A1
Filing date	Feb 23, 2016
Priority date	Mar 2, 2015
Publication date	Sep 8, 2016
Grant date	—

Abstract

A control system for a transmission includes first and second engagement devices and a controller. The first engagement device brings first dog teeth of a first member into engagement with second dog teeth of a second member to enable torque transmission therebetween. The second engagement device connects a third member and a fourth member while changing a torque transmitting capacity therebetween. The transmission establishes a predetermined gear stage by bringing into engagement the first engagement device and the second engagement device. The controller is configured to bring the first engagement device into engagement while reducing a torque transmitting capacity of the second engagement device and then to increase the torque transmitting capacity of the second engagement device, when shifting a gear stage from another gear stage established by bringing the first engagement device into disengagement while bringing the second engagement device into engagement to said predetermined gear stage.

First claim

What is claimed is:

1 . A control system for a transmission comprising:
a first engagement device that brings first dog teeth of a first member into engagement with second dog teeth of a second member to enable torque transmission therebetween; a second engagement device that connects a third member and a fourth member while changing a torque transmitting capacity therebetween; and a controller, wherein the transmission establishes a predetermined gear stage by bringing into engagement the first engagement device and the second engagement device, and the controller is configured to bring the first engagement device into engagement while reducing a torque transmitting capacity of the second engagement device and then to increase the torque transmitting capacity of the second engagement device, when shifting a gear stage from another gear stage established by bringing the first engagement device into disengagement while bringing the second engagement device into engagement to said predetermined gear stage.

2 . The control system for a transmission as claimed in claim 1 , wherein the controller is further configured to reduce the torque transmitting capacity of the second engagement device to a predetermined level at which a relative rotation between the third member and the fourth member is achieved when shifting the gear stage from said another gear stage to said predetermined gear stage.

3 . The control system for a transmission as claimed in claim 2 , wherein the controller is further configured to bring the first dog teeth into engagement with the second dog teeth after reducing the torque transmitting capacity of the second engagement device to the predetermined level.

4 . The control system for a transmission as claimed in claim 1 , wherein the controller is further configured to gradually increase the torque transmitting capacity of the second engagement device after bringing the first engagement device into engagement.

5 . The control system for a transmission as claimed in claim 1 , wherein at least one of the first dog teeth and the second dog teeth includes a chamfered leading end to allow the first member to rotate in a direction to be engaged smoothly with the second member when the second dog teeth come into contact with the first dog teeth in an initial phase of engagement.

6 . The control system for a transmission as claimed in claim 1 ,
wherein a gear ratio of said predetermined gear stage is larger than that of said another gear stage, and wherein the controller is further configured to shift the gear stage from said another gear stage to said predetermined gear stage when an input speed of the transmission is reduced.

7 . The control system for a transmission as claimed in claim 1 ,
wherein a gear ratio of said predetermined gear stage is smaller than that of said another gear stage, and wherein the controller is further configured to shift the gear stage from said another gear stage to said predetermined gear stage when an input speed of the transmission is increased.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kuwahara Seiji
• Yoshino Hirotsugu

Classifications

• F16H2200/2097

  comprising an orbital gear set member permanently connected to the housing, e.g. a sun wheel permanently connected to the housing · CPC title

• F16D23/00 Primary

  Details of mechanically-actuated clutches not specific for one distinct type · CPC title

• F16H2200/006

  the gear ratios comprising eight forward speeds · CPC title

• F16D25/061

  the clutch having interengaging clutch members · CPC title

• F16H61/0204

  for gearshift control, e.g. control functions for performing shifting or generation of shift signal · CPC title