Hydraulic transaxle

Patent metadata

Field	Value
Publication number	US-10895249-B2
Application number	US-201715487058-A
Country	US
Kind code	B2
Filing date	Apr 13, 2017
Priority date	Jul 5, 2013
Publication date	Jan 19, 2021
Grant date	Jan 19, 2021

Abstract

A hydraulic transaxle comprises an axial piston hydraulic pump having a variable displacement, and a transaxle casing incorporating the hydraulic pump. The hydraulic pump includes a movable swash plate and a pair of trunnion shafts. The transaxle casing includes a pair of side walls, and includes a pair of casing holes each of which penetrates each of the side walls between an inside and an outside of the transaxle casing. The pair of trunnion shafts are passed through the respective casing holes. The swash plate is formed with a pair of swash plate holes in the respective side portions facing the respective side walls in the inside of the transaxle casing. Proximal end portions of the respective trunnion shafts are inserted into the respective swash plate holes. A distal end portion of one of the trunnion shafts projects from the corresponding casing hole to the outside of the transaxle casing.

First claim

What is claimed is:

1. A hydraulic transaxle, comprising:
a hydraulic pump having a variable displacement, wherein the hydraulic pump includes a movable swash plate and a pair of trunnion shafts coaxial to each other, the pair of trunnion shafts being joined to the swash plate separably from the swash plate,
wherein the swash plate is rotatable centered on a common axis of the trunnion shafts to control the displacement of the hydraulic pump, the common axis of the trunnion shafts defining an axial direction of the trunnion shafts perpendicular to a rotary axis of the hydraulic pump; and
a transaxle casing incorporating the hydraulic pump,
wherein the transaxle casing includes a pair of side walls opposite each other in the axial direction of the trunnion shafts with respect to the hydraulic pump,
wherein the transaxle casing includes a pair of casing holes each of which penetrates each of the side walls between an inside of the transaxle casing and an outside of the transaxle casing,
wherein the pair of trunnion shafts are passed through the respective casing holes to be pivotally supported by the respective side walls of the transaxle casing,

wherein the swash plate is formed with a pair of side portions opposite each other in the axial direction of the trunnion shafts, the pair of side portions facing the respective side walls in the inside of the transaxle casing,
wherein the swash plate is formed with a pair of swash plate holes in the respective side portions, the pair of swash plate holes being open to the pair of casing holes, respectively
wherein proximal end portions of the respective trunnion shafts are inserted into the respective swash plate holes to be engaged to the swash plate unrotatably, relative to the swash plate, and
wherein a distal end portion of one of the trunnion shafts projects from the corresponding casing hole to the outside of the transaxle casing so as to be operatively connected to an operation device for controlling the displacement of the hydraulic pump,
the hydraulic transaxle further comprising:
a control arm provided on an outside end portion of a corresponding one of the side walls of the transaxle casing to be fixed on the distal end portion of the one of the trunnion shafts so as to operatively connect the swash plate to the operation device; and
a neutral biasing mechanism for biasing the swash plate to a neutral position for the hydraulic pump,

wherein the trunnion shafts are identical in shape to each other, and
wherein the neutral biasing mechanism is provided on an outside end portion of the other of the side walls of the transaxle casing to be provided on a distal end portion of the other of the trunnion shafts.

2. The hydraulic transaxle according to claim 1 , wherein the pair of side portions of the swash plate are formed with respective distal end surfaces that are adjacent to inside surfaces of the respective side walls of the transaxle casing so that a width of the swash plate between the distal end surfaces in the axial direction of the trunnion shafts is equal to or slightly less than a distance between the inside surfaces of the side walls of the transaxle casing in the axial direction of the trunnion shafts.

3. A hydraulic transaxle, comprising:
a hydraulic pump having a variable displacement, wherein the hydraulic pump includes a movable swash plate and a pair of trunnion shafts coaxial to each other, the pair of trunnion shafts being joined to the swash plate separably from the swash plate,
wherein the swash plate is rotatable centered on a common axis of the trunnion shafts to control the displacement of the hydraulic pump, the common axis of the trunnion shafts defining an axial direction of the trunnion shafts perpendicular to a rotary axis of the hydraulic pump; and
a transaxle casing incorporating the hydraulic pump,
wherein the transaxle casing includes a pair of side walls opposite each other in the axial direction of the trunnion shafts with respect to the hydraulic pump,

wherein the transaxle casing includes a pair of casing holes each of which penetrates each of the side walls between an inside of the transaxle casing and an outside of the transaxle casing,
wherein the pair of trunnion shafts are passed through the respective casing holes to be pivotally supported by the respective side walls of the transaxle casing,
wherein the swash plate is formed with a pair of side portions opposite each other in the axial direction of the trunnion shafts, the pair of side portions facing the respective side walls in the inside of the transaxle casing,
wherein the swash plate is formed with a pair of swash plate holes in the respective side portions, the pair of swash plate holes being open to the pair of casing holes, respectively
wherein proximal end portions of the respective trunnion shafts are inserted into the respective swash plate holes to be engaged to the swash plate unrotatably, relative to the swash plate,
wherein a distal end portion of one of the trunnion shafts projects from the corresponding casing hole to the outside of the transaxle casing so as to be operatively connected to an operation device for controlling the displacement of the hydraulic pump wherein the transaxle casing includes at least two housing members joined to each other at a joint plane parallel to the common axis of the trunnion shafts, and
wherein one of the at least two housing members is formed integrally with the pair of side walls having the respective casing holes.

4. The hydraulic transaxle according to claim 3 , further comprising:
a control arm provided on an outside end portion of a corresponding one of the side walls of the transaxle casing to be fixed on the distal end portion of the one of the trunnion shafts so as to operatively connect the swash plate to the operation device; and
a neutral biasing mechanism for biasing the swash plate to a neutral position for the hydraulic pump,
wherein the trunnion shafts are identical in shape to each other, and
wherein the neutral biasing mechanism is provided on an outside end portion of the other of the side walls of the transaxle casing to be provided on a distal end portion of the other of the trunnion shafts.

5. A hydraulic transaxle, comprising:
a hydraulic pump having a variable displacement;
a movable swash plate disposed in the hydraulic pump;
a transaxle casing including the hydraulic pump; and
a pair of trunnion shafts rotatably mounted to the transaxle casing in a pair of casing holes, respectively, the pair of trunnion shafts being disposed coaxial to each other and being removably fixed to the swash plate,
wherein the swash plate is rotatably centered on a common axis of the trunnion shafts to control the displacement of the hydraulic pump, the common axis of the trunnion shafts being perpendicular to a rotary axis of the hydraulic pump; and
wherein the casing holes penetrate a side wall of the transaxle case between an inside of the transaxle casing and an outside of the transaxle casing such that the trunnion shafts are configured to be removed through the casing holes to the exterior of the transaxle casing,
wherein a distal end portion of one of the trunnion shafts projects from the corresponding casing hole to the outside of the transaxle casing so as to be operatively connected to an operation device for controlling the displacement of the hydraulic pump, and
wherein the swash plate is configured to be removable from the transaxle casing in a direction along the rotary axis of the hydraulic pump after removal of the trunnion shafts.

6. The hydraulic transaxle according to claim 5 , wherein the pair of side portions of the swash plate are formed with respective distal end surfaces that are adjacent to inside surfaces of the respect

Assignees

• Kanzaki Kokyukoki Mfg Co Ltd

Inventors

• Murashima Daisuke
• Iwaki Koji
• Yasuda Toshifumi
• Mizukawa Katsumoto

Classifications

• F16H61/4174

  Control of venting, e.g. removing trapped air · CPC title

• F16H39/42

  pump and motor being of different types · CPC title

• F04B49/123 Primary

  by changing the eccentricity of one element relative to another element · CPC title

• F04B1/146 Primary

  Swash plates; Actuating elements · CPC title

• F16H39/14

  with cylinders carried in rotary cylinder blocks or cylinder-bearing members · CPC title