Hydraulic drive vehicle

• US 7,533,753 B2
• Filed: 10/30/2007
• Issued: 05/19/2009
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd. (Yanmar Holdings Co., Ltd.)
• Original Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd. (Yanmar Holdings Co., Ltd.)
• Inventors: Tsukamoto, Michio, Okada, Hideaki
• Primary Examiner(s): Hurley; Kevin
• Application Number:
  US11/976,996
• Publication Number:
  US 20080053734A1
• Time in Patent Office: 567 Days
• Field of Search: 180/233, 180/235, 180/242, 180/305, 180/307
• US Class Current: 180/242
• CPC Class Codes: A01D 69/03 fluid
• CPC Class Codes: B60K 17/105 Units comprising at least a part of the gearing and a torque-transmitting axle, e.g. transaxles B60K17/14 takes precedence
• CPC Class Codes: B60K 17/356 having fluid or electric motor, for driving one or more wheels disposition of motor in, or adjacent to, traction wheel B60K7/00
• CPC Class Codes: B60Y 2200/223 Ridable lawn mowers
• CPC Class Codes: F15B 2211/20523 Internal combustion engine
• CPC Class Codes: F15B 2211/20546 variable capacity
• CPC Class Codes: F15B 2211/7058 Rotary output members
• CPC Class Codes: F15B 2211/7121 the chambers being connected in series
• CPC Class Codes: F16D 31/02 using pumps with pistons or plungers working in cylinders
• CPC Class Codes: F16H 39/14 with cylinders carried in rotary cylinder blocks or cylinder-bearing members
• CPC Class Codes: F16H 61/4165 Control of cooling or lubricating
• CPC Class Codes: F16H 61/444 by changing the number of pump or motor units in operation

Abstract

A hydraulic driving vehicle comprises front and rear transaxles incorporating respective hydraulic motors, and a pump unit separated from the front and rear transaxles. The pump unit incorporates a hydraulic pump having a pump shaft. A hydraulic circuit is formed by piping between the pump unit and the front and rear transaxles so as to circulate hydraulic fluid between the hydraulic pump and the hydraulic motors. A reservoir tank of the hydraulic fluid is connected to the hydraulic circuit by piping. A first cooling fan blowing air away from the pump unit and a second cooling fan blowing air toward the pump unit are disposed oppositely to each other with respect to the pump unit and drivingly connected to the pump shaft. At least a pipe for the piping of the hydraulic circuit and the reservoir tank passes an area blown by each of the first and second cooling fans.

Claims

1. A hydraulic wheel driving apparatus for a vehicle, comprising:

a first transaxle incorporating a first hydraulic motor and formed therein with a first fluid sump;

a second transaxle incorporating a second hydraulic motor and formed therein with a second fluid sump; and

a pump unit incorporating a hydraulic pump for hydraulically driving the first and second hydraulic motors, the pump unit being provided therein with a third fluid sump, wherein the pump unit, the first transaxle and the second transaxle are disposed separately from one another, and the hydraulic pump, the first hydraulic motor and the second hydraulic motor are fluidly connected to one another through a closed fluid circuit by pipes thereamong,

wherein the first transaxle includes a first bypass valve provided to the first hydraulic motor so as to be able to connect the closed fluid circuit to the first fluid sump,

wherein the second transaxle includes a second bypass valve provided to the second hydraulic motor so as to be able to connect the closed fluid circuit to the second fluid sump, and

wherein the pump unit includes a third bypass valve provided to the hydraulic pump so as to be able to connect the closed fluid circuit to the third fluid sump.

2. The hydraulic wheel driving apparatus according to claim 1, further comprising:

a reservoir tank fluidly connected to the first, second and third fluid sumps by respective pipes.