초록 ▼

A vehicle and vehicle drive apparatus having a hydraulic pump and a first and second hydraulic motor, each disposed on a center section, is disclosed. A main housing having a housing cover contains the hydraulic pump and the first and second hydraulic motors, which in turn drive first and second mot

A vehicle and vehicle drive apparatus having a hydraulic pump and a first and second hydraulic motor, each disposed on a center section, is disclosed. A main housing having a housing cover contains the hydraulic pump and the first and second hydraulic motors, which in turn drive first and second motor shafts, respectively. The first and second motor shafts are enclosed in first and second motor shaft housings, respectively, and the main housing combined with the housing cover and the first and second motor shaft housings form a sealed sump. The main housing has mounted thereon a pinion shaft, a pinion gear and a steering rack meshed with the pinion gear. A first steering arm is rotatably mounted to the first motor shaft housing and connected to the steering rack and a second steering arm is rotatably mounted to the second motor shaft housing and connected to the steering rack.

대표청구항 ▼

1. A drive apparatus for a vehicle having a prime mover, the drive apparatus comprising: a housing forming a sump and comprising a main housing member and a housing cover sealed thereto;a transmission disposed in the sump and comprising: a center section containing porting;a hydraulic pump disposed

1. A drive apparatus for a vehicle having a prime mover, the drive apparatus comprising: a housing forming a sump and comprising a main housing member and a housing cover sealed thereto;a transmission disposed in the sump and comprising: a center section containing porting;a hydraulic pump disposed on the center section; anda first hydraulic motor engaged to and driving a first motor shaft and a second hydraulic motor engaged to and driving a second motor shaft, wherein both hydraulic motors are disposed on the center section and in hydraulic communication with the hydraulic pump through the porting to form a hydraulic circuit;a first motor shaft housing joined to the main housing member and enclosing the first motor shaft, and a second motor shaft housing joined to the main housing member and enclosing the second motor shaft;a pinion shaft having a pinion gear and rotatably mounted on the main housing member;a steering rack having a sector gear meshed with the pinion gear and rotatably mounted on the main housing member;a first steering arm rotatably mounted to the first motor shaft housing and connected to the steering rack via a first connector; anda second steering arm rotatably mounted to the second motor shaft housing and connected to the steering rack via a second connector. 2. The drive apparatus of claim 1, wherein the center section has a first motor running surface at a first end of the center section and defining a first plane, a second motor running surface at a second end of the center section and defining a second plane, and a pump running surface on a middle portion of the center section and defining a third plane. 3. The drive apparatus of claim 2, wherein the first plane is not parallel to the second plane, and the first and second planes are both perpendicular to the third plane. 4. The drive apparatus of claim 1, further comprising a charge pump disposed on the center section, wherein the charge pump is in fluid communication with the sump via porting in the center section, a charge relief valve positioned between the charge pump and the sump, and a charge gallery defined by a portion of the main housing member and a portion of the center section, the charge gallery being and in fluid communication with the charge pump. 5. The drive apparatus of claim 4, further comprising a shock valve disposed in an opening in the center section and in hydraulic communication with the charge gallery and one of a low pressure side and a high pressure side of the hydraulic circuit. 6. The drive apparatus of claim 1, further comprising a first support member extending from an interior portion of the main housing member and a second support member extending from the housing cover and sealed to the first support member to form a support structure, the support structure passing through an opening in the center section. 7. The drive apparatus of claim 6, wherein the support structure has one or more openings each capable of receiving a fastener for attaching the drive apparatus to the prime mover. 8. A drive apparatus for a vehicle having a prime mover, the drive apparatus comprising: a housing forming an internal sump and comprising a main housing member and a housing cover sealed thereto;a transmission disposed in the internal sump and comprising: a center section containing porting;a hydraulic pump disposed on the center section; anda first hydraulic motor engaged to and driving a first motor shaft and a second hydraulic motor engaged to and driving a second motor shaft, wherein both hydraulic motors are disposed on the center section and in hydraulic communication with the hydraulic pump through the porting to form a hydraulic circuit;a first motor shaft housing joined to the main housing member and enclosing the first motor shaft, and a second motor shaft housing joined to the main housing member and enclosing the second motor shaft; anda first steerable hub assembly having a first set of reduction gearing engaged to the first motor shaft and a second steerable hub assembly having a second set of reduction gearing engaged to the second motor shaft, wherein the first set of reduction gearing and the second set of reduction gearing each comprise: a pinion gear driven by the respective motor shaft;an upper bevel gear drivingly engaged to the pinion gear;a gear shaft fixed to and driven by the upper bevel gear;a lower gear driven by the gear shaft; anda hub gear drivingly engaged to the lower gear. 9. The drive apparatus of claim 8, further comprising: a first journal opening formed in the center section, wherein a first end of the first motor shaft is disposed in the first journal opening; anda second journal opening formed in the center section, wherein a first end of the second motor shaft is disposed in the second journal opening. 10. The drive apparatus of claim 8, further comprising a first expansion bellows disposed in the first motor shaft housing, wherein the first expansion bellows is in pneumatic communication with a first breather port formed in the main housing member. 11. The drive apparatus of claim 10, further comprising a second expansion bellows disposed in the second motor shaft housing, wherein the second expansion bellows is in pneumatic communication with a second breather port formed in the main housing member. 12. The drive apparatus of claim 10, wherein the first set of reduction gearing and the second set of reduction gearing each further comprise a pivot tube supported in the respective motor shaft housing, wherein each respective gear shaft is rotationally disposed in and extends through its respective pivot tube. 13. A drive apparatus comprising: a housing forming an internal sump;a transmission disposed in the sump and driving a first motor shaft and a second motor shaft;a pinion shaft rotatably mounted on the housing and having a first pinion gear;a steering rack rotatably mounted directly on the housing and having a sector gear meshed with the first pinion gear;a first steering arm rotatably mounted directly on the housing and connected to the steering rack;a second steering arm rotatably mounted directly on the housing and connected to the steering rack;a first steerable hub assembly having a first set of reduction gearing engaged to the first motor shaft; anda second steerable hub assembly having a second set of reduction gearing engaged to the second motor shaft. 14. The drive apparatus of claim 13, wherein the first set of reduction gearing and the second set of reduction gearing each comprise a motor shaft pinion gear driven by the respective motor shaft, an upper bevel gear drivingly engaged to the motor shaft pinion gear, a gear shaft fixed to and driven by the upper bevel gear, a lower gear driven by the gear shaft, and a hub gear drivingly engaged to the lower gear. 15. The drive apparatus of claim 14, wherein the housing comprises a main housing member, a first motor shaft housing portion and a second motor shaft housing portion, and wherein the first set of reduction gearing and the second set of reduction gearing each further comprise a pivot tube supported in the respective motor shaft housing portion, wherein each respective gear shaft is rotationally disposed in and extends through its respective pivot tube. 16. The drive apparatus of claim 13, wherein the housing comprises a main housing member, a first motor shaft housing portion and a second motor shaft housing portion, and the drive apparatus further comprises a first expansion bellows disposed in the first motor shaft housing portion and a second expansion bellows disposed in the second motor shaft housing portion, wherein the first expansion bellows is in pneumatic communication with a first breather port formed in the housing and the second expansion bellows is in pneumatic communication with a second breather port formed in the housing. 17. The drive apparatus of claim 13, wherein the housing comprises a main housing member, a first motor shaft housing portion and a second motor shaft housing portion, and the first pinion gear and the steering rack are mounted on the main housing member, the first steering arm is mounted on the first motor shaft housing portion and the second steering arm is mounted on the second motor shaft housing portion. 18. The drive apparatus of claim 17, wherein the transmission comprises: a center section disposed in the sump, wherein the sump is formed in the main housing member;a hydraulic pump disposed on the center section;a first hydraulic motor engaged to and driving the first motor shaft and a second hydraulic motor engaged to and driving the second motor shaft, wherein both hydraulic motors are disposed on the center section and in hydraulic communication with the hydraulic pump through a hydraulic circuit formed in the center section, and the first hydraulic motor comprises a cylinder block; anda bypass mechanism comprising a bypass actuation shaft rotationally supported in the housing and a U-shaped block lift member engaged to the bypass actuation shaft and extending around a portion of the cylinder block, whereby rotation of the bypass actuation shaft causes the block lift member to engage the cylinder block to lift the cylinder block off its running surface to open the hydraulic circuit to the sump. 19. The drive apparatus of claim 17, wherein the first steering arm is rotatably mounted to the first motor shaft housing portion and the second steering arm is rotatably mounted to the second motor shaft housing portion. 20. The drive apparatus of claim 19, wherein the first motor shaft housing portion and the second motor shaft housing portion are secured to the main housing member by means of fasteners. 21. The drive apparatus of claim 20, wherein the transmission comprises a center section disposed in the sump, a hydraulic pump disposed on the center section, a first hydraulic motor engaged to and driving the first motor shaft and a second hydraulic motor engaged to and driving the second motor shaft, wherein both hydraulic motors are disposed on the center section and in hydraulic communication with the hydraulic pump through hydraulic porting formed in the center section. 22. The drive apparatus of claim 21, further comprising a first expansion bellows disposed in the first motor shaft housing portion and a second expansion bellows disposed in the second motor shaft housing portion, wherein the first expansion bellows is in pneumatic communication with a first breather port formed in the housing and the second expansion bellows is in pneumatic communication with a second breather port formed in the housing.