Continuously variable transmission

• US 6,261,200 B1
• Filed: 03/16/2000
• Issued: 07/17/2001
• Est. Priority Date: 10/02/1997
• Status: Expired due to Term

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Miyata, Shinji, Imanishi, Takashi
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US09/526,923
• Time in Patent Office: 488 Days
• Field of Search: 475/186, 475/192
• US Class Current: 475/186
• CPC Class Codes: F16H 2037/0886 with switching means, e.g. to change ranges
• CPC Class Codes: F16H 37/084 at least one power path being a continuously variable transmission, i.e. CVT
• CPC Class Codes: F16H 37/086 CVT using two coaxial friction members cooperating with at least one intermediate friction member

Abstract

In a continuously variable transmission comprising: an input shaft which is rotated by a drive source; an output shaft which takes out a driving force attributing the rotation of the input shaft; and a variator and a planet gear mechanism which are arranged between the input shaft and the output shaft, the variator having a clutch which provides a first mode in which a driving force circulation is carried out, and a second mode in which the driving force circulation is not carried out, the speed of a first driving force transmitting system which is inputted to the planet gear mechanism through the variator and the speed of a second driving force transmitting system which is inputted to the planet gear mechanism directly, not through the variator are detected with first and second speed detecting sensors, and, upon detection of the substantial coincidence in the ratio of speed of the first and second driving force transmitting shafts, the mode switching operation is carried out with the clutches.

Claims

1. A continuously variable transmission comprising:

an input shaft rotated by a drive source;

an output shaft for taking out a driving force attributing a rotation of said input shaft;

a variator being arranged between said input shaft and said output shaft;

a planet gear mechanism arranged between said input shaft and said output shaft;

a switching member for switching a first mode in which a driving force circulation through said variator is carried out and a second mode in which a driving force circulation through said variator is not carried;

a detecting member for detecting a ratio of speed of said output shaft, and a ratio of speed of a second driving force transmitting system which is inputted to said planet gear mechanism directly, not through said variator,

wherein, when said detecting member detects a substantial coincidence in the ratios of speed of said output shaft and said second driving force transmitting system, said detecting member performs a mode switching operation using said switching member.

2. The continuously variable transmission according to claim 1, wherein said variator includes:

a pair of input disks being confronted with each other, said input disks rotating in association with said input shaft;

a pair of output disks being coaxially arranged between said input disks; and

a second driving power transmitting shaft provided at a second end of said input shaft, and

said detecting member includes;

a first speed detecting sensor for detecting number of revolutions of said output shaft; and

a second speed detecting sensor for detecting number of revolutions of said second driving power transmitting shaft.

3. The continuously variable transmission according to claim 2, wherein said planet gear mechanism includes:

a sun gear coupled with said output shaft;

a plurality of planet gears engaged with said sun gear;

a carrier engaging with said planet gears; and

a ring gear engaging with said planet gears, and

said switching member includes;

a low speed clutch located between said carrier and said ring gear; and

a high speed clutch provided coupled to said second driving power transmitting shaft.

4. The continuously variable transmission according to claim 1, wherein said variator includes:

a pair of input disks being confronted with each other, said input disks rotating in association with said input shaft; and

a pair of output disks being coaxially arranged between said input disks, and

said detecting member includes;

a first speed detecting sensor for detecting number of revolutions of said output shaft; and

a second speed detecting sensor for detecting number of revolutions of said input disks.

5. A continuously variable transmission used as an automobile transmission comprising:

an input shaft rotated by a drive source;

an output shaft for taking out a driving force attributing a rotation of said input shaft;

a variator being arranged between said input shaft and said output shaft, said variator including;

a) a pair of input disks being confronted with each other, said input disks rotating in association with said input shaft, and

b) a pair of output disks being coaxially arranged between said input disks in a loosely engaging state;

a loose engage shaft for connecting said output disks;

a first driving power transmitting shaft in association with said loose engaging shaft, through a first sprocket and a chain;

a second driving power transmitting shaft provided at a second end of said input shaft;

a planet gear mechanism arranged between said input shaft and said output shaft, said planet gear mechanism including;

a) a sun gear coupled with said output shaft;

b) a plurality of planet gears engaged with said sun gear,

c) a carrier engaging with said planet gears, and

d) a ring gear engaging with said planet gears;

a low speed clutch located between said carrier and said ring gear;

a high speed clutch provided coupled to said second driving power transmitting shaft;

a first speed detecting sensor for detecting number of revolutions of said output shaft; and

a second speed detecting sensor for detecting number of revolutions of said second driving power transmitting shaft.

6. A continuously variable transmission used as an automobile transmission comprising:

an input shaft rotated by a drive source;

an output shaft for taking out a driving force attributing a rotation of said input shaft;

a variator being arranged between said input shaft and said output shaft, said variator including;

a) a pair of input disks being confronted with each other, said input disks rotating in association with said input shaft, and

b) a pair of output disks being coaxially arranged between said input disks;

a second driving power transmitting shaft provided at a second end of said input shaft;

a planet gear mechanism arranged between said input shaft and said output shaft, said planet gear mechanism including;

a) a sun gear coupled with said output shaft,

b) a plurality of planet gears engaged with said sun gear,

b) a carrier engaging with said planet gears, and

d) a ring gear engaging with said planet gears;

a low speed clutch located between said carrier and said ring gear;

a high speed clutch provided coupled to said second driving power transmitting shaft;

a first speed detecting sensor for detecting number of revolutions of said output shaft; and

a second speed detecting sensor for detecting number of revolutions of said input disk.