Patent ID: 7353650
Filing Date: 2008-04-08
Classification: B60K,B60Y,F16D,F16H

Abstract:
1. An axle driving apparatus comprising: a common housing having a fluid sump therein; a variable displacement first hydraulic pump disposed in the housing, the first hydraulic pump includes a pump shaft; a hydraulic motor disposed in the housing and fluidly connected to the first hydraulic pump; an axle disposed in the housing and driven by the hydraulic motor; pump displacement control means disposed in the housing so as to control a displacement of the first hydraulic pump; a center section on which the first hydraulic pump and the hydraulic motor are mounted so as to be fluidly connected to each other through a fluid circuit formed in the center section, wherein the center section is formed therein with a cylinder; hydraulically actuated operational force increasing means interposed between the pump displacement control means and a speed changing operation device which is disposed outside the housing so as to be manually operated by an operator, wherein the operational force increasing means supplies the pump displacement control means with an operational force that is greater than a force applied by the operator onto the speed changing operation device for setting a displacement of the first hydraulic pump, and wherein the operational force increasing means includes a hydraulically controlled valve disposed in the center section to be switched by operating the speed changing operation device, and includes a piston axially slidably extended in the cylinder perpendicularly to the pump shaft; and a second hydraulic pump supported by the housing so as to serve as a hydraulic power source for the operational force increasing means, wherein the second hydraulic pump is driven together with the first hydraulic pump so as to suck fluid from the fluid sump in the housing.