Electrically-driven position changing apparatus

• US 6,230,576 B1
• Filed: 09/27/1999
• Issued: 05/15/2001
• Est. Priority Date: 09/28/1998
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Hori, Masashi, Asa, Hironori, Yamada, Yoshichika
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US09/406,136
• Time in Patent Office: 596 Days
• Field of Search: 744/731.2, 743/35
• US Class Current: 74/335
• 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 2063/423 Range indicators for automatic transmissions, e.g. showing selected range or mode
• CPC Class Codes: F16H 59/08 Range selector apparatus
• 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 61/32 Electric motors actuators or related electrical control means therefor
• CPC Class Codes: Y10T 74/19251 Control mechanism
• CPC Class Codes: Y10T 74/2003 Electrical actuator

Abstract

A single actuator such as an electric motor is used to actuate a shift range changing mechanism of an automatic transmission. The motor has a plurality of torque generating units each of which is capable of generating a torque sufficient to effect any shift range changes of the shift range changing mechanism. All of the torque generating units are driven electrically normally in response to a shift range change command. Operation of each torque generating unit is monitored separately from each other. When one of the torque generating units fails in operation, the torque generating unit in failure is not driven but the other torque generating units are driven to effect a shift range change. The failure of the torque generating units is indicated on an indicator in a vehicle. The motor may be a brushless type or a reluctance type.

Claims

1. A shift range changing apparatus for a vehicle automatic transmission comprising:

a shift range changing mechanism for changing shift ranges;

a single actuator for actuating the shift range changing mechanism;

a drive circuit for driving the single actuator; and

a control circuit for controlling the single actuator through the drive circuit in response to a shift change command applied externally to effect a shift range change operation of the shift range changing mechanism,

wherein the single actuator includes a plurality of torque generating units which are operable independently from each other to be capable of actuating the shift range changing mechanism upon occurrence of failure in one of the torque generating units.

2. A shift range changing apparatus of claim 1, wherein:

the control circuit is constructed to detect a failure of each of the torque generating units, and to indicate the detected failure via an indicator.

3. A shift range changing apparatus of claim 2, wherein:

the control circuit is constructed to drive all of the torque generating units which are free of failure in response to the shift range change command; and

the single actuator is constructed to actuate the shift range changing mechanism with a sum of torque generated by the torque generating units which are free of failure.

4. A shift range changing apparatus of claim 1, wherein:

each of the torque generating units is constructed to generate a torque which is sufficient to actuate the shift range changing mechanism for effecting the shift range change independently.

5. A shift range changing apparatus of claim 1, wherein:

the drive circuit includes a plurality of drive means which drive the torque generating units independently from each other, respectively.

6. A shift range changing apparatus of claim 1, wherein:

the single actuator is an electric motor which has a single rotor, a plurality of stators arranged to face the rotor and spaced apart in an axial direction of the rotor, and a plurality of windings wound around each of the stators, so that each of the stators and the windings operates to rotate the single rotor independently as the torque generating units.

7. A shift range changing apparatus of claim 1, wherein:

the single actuator is an electric motor which has a rotor, a stator arranged to face the rotor and having a plurality of magnetic poles divided into a plurality of groups in a circumferential direction, and a plurality of windings wound around the magnetic poles respectively, so that each of the magnetic poles and the windings operates to rotate the rotor independently as the torque generating units.

8. A shift range changing apparatus of claim 1, wherein:

the single actuator is an electric motor which has a rotor, a stator arranged to face the rotor and having a plurality of magnetic poles, and a plurality of windings wound around each of the magnetic poles and connected in parallel, so that each of the magnetic poles and the windings thereon operates to rotate the rotor independently as one of the torque generating units.

9. A shift range changing apparatus of claim 1, wherein:

the single actuator is an electric motor having a rotation shaft; and

the shift range changing mechanism has a drive shaft which is directly coupled with the rotation shaft.

10. A shift range changing apparatus of claim 1, wherein:

each of the torque generating units is constructed to generate a torque which is sufficient to actuate the shift range changing mechanism for effecting the shift range change to and from a parking range independently.