Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
2001-08-10
2002-12-31
Wright, Dirk (Department: 3682)
Machine element or mechanism
Gearing
Interchangeably locked
C074S473120
Reexamination Certificate
active
06499371
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a range switching apparatus used for switching a drive range of, for example, an automatic transmission.
BACKGROUND ART
Conventionally, a range switching apparatus for switching a drive range of an automatic transmission, for example, which has a structure constituted by a valve for switching the drive range within the transmission, for example, a manual valve, and a shift lever connected to the valve by a shift cable and provided within a vehicle cabin has been known. The apparatus is structured such as to switch the manual valve via the shift cable in accordance with an operation by a driver applied to the shift lever.
However, in view of requests for expanded freedom of design within the vehicle cabin in recent motor vehicles, requests for expanded derivative types of motor vehicles produced from the same platform and the like, there is a trend that the expansion of freedom of placing the shift lever is becoming necessary. Accordingly, since the shift cable connecting the shift lever and the manual valve is restricted in view of its layout, the development of a range switching apparatus using no shift cable is desired.
Accordingly, there has been proposed in Japanese Utility Model Publication No. HEI 7-16067 and the like a range switching apparatus in which a range switching operation is performed by using an electric motor and an electromagnetic clutch.
The range switching apparatus has two motors comprising first and second motors, and a planetary gear mechanism. The first motor is connected to a sun gear in the planetary gear mechanism via a worm gear and a clutch. The second motor is connected to a planetary gear via a worm gear. Generally, the structure is made such that the second motor is stopped, a plurality of planetary gears do not move around the sun gear, and a torque of the first motor can be output from a ring gear surrounding a plurality of planetary gears and engaged with the planetary gears. The structure is made such that the output torque is further transmitted to a range control shaft (a shaft connected to the manual valve) via a speed reduction mechanism. Further, the second motor is structured such as to be driven when the first motor fails; however, since the first motor and the second motor are interlocked with each other via the planetary gears, they are not affected by one other.
Further, a range switching apparatus provided with a function of detecting a switching position of the manual valve is disclosed in Japanese Patent No. 2904290. This range switching apparatus is also structured so as to switch the manual valve in the automatic transmission by a motor. Further, an electromagnetic clutch is provided between the motor and a manual valve. Further, a position sensor for detecting the switching position of the manual valve is provided in the motor.
However, the range switching apparatus disclosed in Japanese Utility Model Publication No. HEI 7-16067 has the following problems.
First, since there are provided two motors and a planetary gear mechanism for transmitting the torque of the two motors, the structure is complex. Accordingly, the size of the range switching apparatus is increased.
Further, since two worm gears correspond to the two motors, the planetary gears and the ring gear are supported in a casing of the range switching apparatus and supported on a gear shaft which does not transmit power, the size of the range switching apparatus is further increased.
Further, the electric motor corresponding to a drive source is connected to an adsorbed disc in the electromagnetic clutch, and an adsorption rotor forming a magnetic field of the electromagnetic clutch is connected to a gear speed reduction mechanism in the side of a detent lever. Generally, since the adsorption rotor is formed so that the mass of the adsorption rotor is significantly greater than that of the adsorbed disc, an inertia of the adsorption rotor connected to the side of the detent lever is large even when the clutch is disengaged at a predetermined position, so that there is sometimes generated trouble in which the detent lever is rotated via the gear speed reduction mechanism due to an inertia force of the adsorption rotor so as to pass through the required shift range.
This tendency is significantly generated in the case where the driver operates the shift lever and drives the electric motor at a high speed so as to complete the range switching motion without delay and obtain a good shift feeling, and can not be ignored. That is because the revolution speed of the electromagnetic clutch connected to the electric motor becomes faster than the revolution speed of the electric motor and the inertia force of the adsorption rotor is increased that amount.
In order to solve the problems mentioned above, a method of adjusting a disengagement timing of the clutch is conceivable; however, if the inertia force of the adsorption rotor is large, it is necessary to disengage the clutch before a roller of the detent spring goes over a projection immediately before a range engagement groove formed so as to correspond to respective shift positions of the detent lever. In this case, it is indefinite whether or not the roller of the detent spring is securely received within a target range engagement groove, and the apparatus lacks reliability.
Further, since the position sensor in the apparatus switching the manual valve which is disclosed in Japanese Patent No. 2904290 is provided in the motor, only an angle of rotation of the motor can be detected. Accordingly, since it is impossible to directly detect the position of the range control shaft for operating the manual valve when disengaging the clutch, it is impossible to accurately control the switching position of the manual valve.
In view of the matters mentioned above, it is an object of the present invention to provide a compact range switching apparatus having a simple structure.
An object of the present invention is to provide a range switching apparatus of an automatic transmission which can reliably switch to a target range position, can realize a good shift feeling, and has high reliability.
An object of the present invention is to provide a range switching apparatus for reliably detecting a range switching position.
DISCLOSURE OF THE INVENTION
The invention as defined in claim
1
includes range switching means for switching a range; driving means for driving the range switching means; speed reducing means for reducing a drive force of the driving means and transmit the drive force to the range switching means; and a clutch for connecting and disconnecting a power transmitting state between the driving means and the speed reducing means, wherein a power output member of the clutch is connected to a power input member of the speed reducing means.
Accordingly, since the power output member of the clutch is directly connected to the power input member of the speed reducing means via no other members, it is possible to make the range switching apparatus compact.
Further, since the clutch is provided on the side of the driving means rather than on the side of the speed reducing means, a torque amplified by the speed reducing means is not applied to the clutch, so that a capacity of the clutch can be reduced and it is possible to make the range switching apparatus compact.
The invention as defined in claim
2
is dependent on claim
1
, and further includes a position detecting sensor for detecting a range switching position of the range switching means between the range switching means and the speed reducing means.
Accordingly, since the range switching position of the range switching means is detected by the position detecting sensor between the range switching means and the speed reducing means, it is possible to reliably detect the switching position by the range switching means.
The invention as defined in claim
3
is dependent on claim
2
, and is such that the position detecting sensor detects a motion of the power output member of the speed reducing means.
Accordingly, sinc
Eishima Hirotoshi
Maeda Jiro
Murase Yoshitaka
Ohkoshi Naoki
Takemoto Kazuo
Aisin Aw Co. Ltd.
Wright Dirk
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