Automatic transmission

• US 8,657,718 B2
• Filed: 03/04/2013
• Issued: 02/25/2014
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Iizuka, Kohei, Sugino, Soichi
• Primary Examiner(s): Holmes, Justin
• Application Number:
  US13/783,394
• Publication Number:
  US 20130244826A1
• Time in Patent Office: 358 Days
• Field of Search: 475/275, 475/277, 475/282, 475/283, 475/296, 475/330
• US Class Current: 475/283
• CPC Class Codes: F16H 2200/0069 the gear ratios comprising ten forward speeds
• CPC Class Codes: F16H 2200/2012 with four sets of orbital gears
• CPC Class Codes: F16H 2200/2048 with seven engaging means
• CPC Class Codes: F16H 2200/2082 one freewheel mechanisms
• CPC Class Codes: F16H 3/62 Gearings having three or more central gears F16H3/68 - F16H3/78 take precedence
• CPC Class Codes: F16H 3/66 composed of a number of gear trains without drive passing from one train to another

Abstract

An automatic transmission includes an input shaft, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, and an engagement mechanism. The engagement mechanism includes first to seventh engagement devices. Nine or more forward transmission gear ratios are established by setting each of at least three engagement devices among the first to seventh engagement devices in an engagement mode.

Claims

1. An automatic transmission comprising:

an input shaft rotatably supported inside a transmission case and rotatable by a driving force received from a drive source, a rotational speed of the input shaft being changeable into a plurality of rotational speeds through a plurality of gear ratios to be output from an output member;

a first planetary gear set including a first sun gear, a first carrier, and a first ring gear defined as a first element, a second element, and a third element;

a second planetary gear set including a second sun gear, a second carrier, and a second ring gear defined as a fourth element, a fifth element, and a sixth element;

a third planetary gear set including a third sun gear, a third carrier, and a third ring gear defined as a seventh element, an eighth element, and a ninth element;

a fourth planetary gear set including a fourth sun gear, a fourth carrier, and a fourth ring gear defined as a tenth element, an eleventh element, and a twelfth element, the first element being connected to the input shaft, the tenth element being connected to the output member, the second element being connected to the fifth and ninth elements to form a first connected member, the third element being connected to the twelfth element to form a second connected member, the eighth element being connected to the eleventh element to form a third connected member; and

an engagement mechanism comprising;

a first engagement device switchable between an engagement mode in which the first element is connected to the third connected member and a release mode in which the first element is disconnected from the third connected member;

a second engagement device switchable between an engagement mode in which the first element is connected to the fourth element and a release mode in which the first element is disconnected from the fourth element;

a third engagement device switchable between an engagement mode in which the sixth element is connected to the second connected member and a release mode in which the sixth element is disconnected from the second connected member;

a fourth engagement device switchable between an engagement mode in which any two of the tenth element, the second connected member, and the third connected member are connected to each other and a release mode in which said two of the tenth element, the second connected member, and the third connected member are disconnected from each other;

a fifth engagement device switchable between an engagement mode in which the seventh element is connected to the transmission case and a release mode in which the seventh element is disconnected from the transmission case;

a sixth engagement device switchable between an engagement mode in which the sixth element is connected to the transmission case and a release mode in which the sixth element is disconnected from the transmission case; and

a seventh engagement device switchable between an engagement mode in which the fourth element is connected to the transmission case and a release mode in which the fourth element is disconnected from the transmission case, nine or more forward transmission gear ratios being established by setting each of at least three engagement devices among the first to seventh engagement devices in the engagement mode.

2. The automatic transmission according to claim 1,

wherein the first ring gear of the first planetary gear set is defined as the third element,

wherein the fourth sun gear of the fourth planetary gear set is defined as the twelfth element,

wherein the fourth planetary gear set is disposed outward of the first planetary gear set in a radial direction, and

wherein the fourth sun gear of the fourth planetary gear set and the first ring gear of the first planetary gear set are integrated with each other to form the second connected member.

3. The automatic transmission according to claim 1, wherein at least one of the fourth engagement device, the fifth engagement device, and the seventh engagement device comprises a meshing mechanism.

4. The automatic transmission according to claim 1, further comprising:

a one-way clutch to allow a normal rotation of the fourth element and to inhibit a reverse rotation of the fourth element,

wherein the seventh engagement device comprises a friction engagement clutch, and

wherein the one-way clutch is disposed parallel to the friction engagement clutch.

5. The automatic transmission according to claim 1, further comprising:

a start clutch to transfer the driving force of the drive source to the input shaft.

6. The automatic transmission according to claim 1, further comprising:

a torque converter to transfer the driving force of the drive source to the input shaft.

7. The automatic transmission according to claim 1,

wherein the first sun gear of the first planetary gear set is defined as the first element,

wherein the first carrier of the first planetary gear set is defined as the second element, and

wherein the first ring gear of the first planetary gear set is defined as the third element.

8. The automatic transmission according to claim 1,

wherein the second sun gear of the second planetary gear set is defined as the sixth element,

wherein the second carrier of the second planetary gear set is defined as the fifth element, and

wherein the second ring gear of the second planetary gear set is defined as the fourth element.

9. The automatic transmission according to claim 1,

wherein the third sun gear of the third planetary gear set is defined as the seventh element,

wherein the third carrier of the third planetary gear set is defined as the eighth element, and

wherein the third ring gear of the third planetary gear set is defined as the ninth element.

10. The automatic transmission according to claim 1,

wherein the fourth sun gear of the fourth planetary gear set is defined as the twelfth element,

wherein the fourth carrier of the fourth planetary gear set is defined as the eleventh element, and

wherein the fourth ring gear of the fourth planetary gear set is defined as the tenth element.

11. The automatic transmission according to claim 1,

wherein the first sun gear of the first planetary gear set is defined as the first element,

wherein the first carrier of the first planetary gear set is defined as the second element,

wherein the first ring gear of the first planetary gear set is defined as the third element,

wherein the second ring gear of the second planetary gear set is defined as the fourth element,

wherein the second carrier of the second planetary gear set is defined as the fifth element,

wherein the second sun gear of the second planetary gear set is defined as the sixth element,

wherein the third sun gear of the third planetary gear set is defined as the seventh element,

wherein the third carrier of the third planetary gear set is defined as the eighth element,

wherein the third ring gear of the third planetary gear set is defined as the ninth element,

wherein the fourth ring gear of the fourth planetary gear set is defined as the tenth element,

wherein the fourth carrier of the fourth planetary gear set is defined as the eleventh element, and

wherein the fourth sun gear of the fourth planetary gear set is defined as the twelfth element.