Method for operating a hydraulic apparatus of a transmission device

Abstract

A method for operating a hydraulic device ( 1 ) of a transmission device having a variable displacement pump ( 2 ) that can be supplied with a hydraulic pressure (p_B) in order to vary the output in the area of an adjusting device ( 3 ), and having at least two pressure circuits (PK, SK) that can be connected to a discharge side ( 24 ) of the adjustable displacement pump ( 2 ) and are assigned different priorities with regard to the supply of hydraulic fluid by the pump. When a change is needed to the operating state of the transmission device for the implementation of which the output of the variable displacement pump ( 2 ) must be elevated relative to its current output, a pressure (p_B) applied in the region of the adjusting device ( 3 ) by a pressure return ( 5 ) is correspondingly modified before changing the operating state.

1 - 11 . (canceled) 
     
     
         12 . A method of operating a hydraulic device ( 1 ) of a transmission device, the hydraulic device comprising a variable displacement pump ( 2 ) that is supplied with a hydraulic pressure (p_B) for varying output in an area of an adjusting device ( 3 ), at least two pressure circuits (PK, SK, TK) being connectable to a discharge side ( 24 ) of the variable displacement pump ( 2 ) are assigned different priorities regarding a supply of hydraulic fluid by the variable displacement pump, a pressure control valve ( 4 ) connecting a lower-priority pressure circuit (SK) being provided between a higher-priority pressure circuit (PK) and the lower-priority pressure circuit (SK) for limiting a pressure (p_PK) of the higher priority pressure circuit (PK), and a pressure return ( 5 ) being provided downstream of the discharge side ( 24 ) of the variable displacement pump ( 2 ) in a direction of the adjusting device ( 3 ) of the variable displacement pump ( 2 ) for adjusting the output of the variable displacement pump ( 2 ) as a function of an operating status of the transmission, the method comprising the step of:
 correspondingly modifying the hydraulic pressure (p_B) applied in the area of the adjusting device ( 3 ), when a change in the operating status of the transmission device is necessary whose implementation requires that the output of the variable displacement pump ( 2 ) be increased relative to its current output, by the pressure return ( 5 ) before the operating status of the transmission changes.   
     
     
         13 . The method according to  claim 12 , further comprising the step of adjusting the hydraulic pressure (p_B) in the pressure return ( 5 ) to a predefined level by elevating a hydraulic fluid flow requirement of at least one consumer suppliable with hydraulic fluid through the higher-priority pressure circuit (PK), and lowering a volume of hydraulic fluid required by the consumer while the operating state of the transmission device is changing. 
     
     
         14 . The method according to  claim 12 , further comprising the step of adapting the hydraulic pressure (p_B) in the pressure return ( 5 ) by varying a hydraulic fluid flow requirement of at least one consumer suppliable with hydraulic fluid through the lower-priority pressure circuit when a change in the operating state of the transmission device is needed, and an elevated displacement volume results in the variable displacement pump ( 2 ). 
     
     
         15 . The method according to  claim 12 , further comprising the step of changing the hydraulic pressure (p_B) in the pressure return ( 5 ) depending on a pilot pressure (p_VS 15 ) that can be applied to the pressure control valve ( 4 ) when a change in the operating state of the transmission device is needed, and an elevated displacement volume results in the variable displacement pump ( 2 ). 
     
     
         16 . The method according to  claim 12 , further comprising the step of providing, downstream of the pressure control valve ( 4 ), another pressure control valve ( 28 ) in an area of which a pressure (p_SK) in the lower-priority pressure circuit (SK) and the hydraulic pressure (p_B) in the pressure return ( 5 ) is adjusted depending on a pilot pressure (p_VS 15 ) when the change in the operating state of the transmission device is needed, and an elevated displacement volume results in the variable displacement pump ( 2 ). 
     
     
         17 . The method according to  claim 12 , further comprising the step of providing a valve ( 6 ) downstream of the pressure control valve ( 4 ) in a region of which a hydraulic volume flow (q_KS) of a pressure circuit (TK) located downstream of the lower-priority pressure circuit (SK) is adjustable depending upon a pilot pressure (p_VS 15 ), with the hydraulic pressure (p_B) in the pressure return ( 5 ) being adjusted in turn depending on the hydraulic flow volume in the region of the downstream pressure circuit (TK). 
     
     
         18 . The method according to  claim 12 , further comprising the step of branching the pressure return ( 5 ) from the lower-priority pressure circuit (SK), and adjusting the delivery rate of the variable displacement pump ( 2 ) by changing the hydraulic fluid flow in the region of the lower-priority pressure circuit (SK). 
     
     
         19 . The method according to  claim 12 , further comprising the step of supplying a valve device ( 9 ) of the adjusting device ( 3 ) in a region of an effective surface ( 19 ) with a pressure (p_B 21 ) that is throttled relative to the hydraulic pressure (p_B) in the pressure return ( 5 ). 
     
     
         20 . The method according to  claim 19 , further comprising the step of applying a pilot pressure (p_VS 18 ) that is adjustable in a region of a pressure adjuster ( 18 ) in area of a second effective surface ( 22 ) of the valve device ( 9 ). 
     
     
         21 . The method according to  claim 12 , further comprising the step of supplying at least one of a cooling and a lubricating fluid circuit (TK) with hydraulic fluid via the lower-priority pressure circuit (SK). 
     
     
         22 . The method according to  claim 12 , further comprising the step of supplying at least one of a cooling and a lubricating fluid circuit with hydraulic fluid via a pressure circuit (TK) located downstream of the lower-priority pressure circuit (SK). 
     
     
         23 . A method of operating a hydraulic device ( 1 ) of a transmission device as a function of an operating state of the transmission device, the hydraulic device ( 1 ) comprising a variable displacement pump ( 2 ) and an adjustment device ( 3 ), the adjustment device ( 3 ) being supplied with a hydraulic pressure (p_B) and adjusting an output of the variable displacement pump ( 2 ) as a function of the hydraulic pressure (p_B), at least a priority pressure circuit (PK) and a secondary pressure circuit (SK) being connectable to the output ( 24 ) of the variable adjustment pump ( 2 ), the priority pressure circuit (PK) having a higher priority of being supplied with hydraulic fluid from the variable adjustment pump ( 2 ) than the secondary pressure circuit (SK), the priority pressure circuit (PK) being directly coupled to the output of the variable displacement pump ( 2 ), a pressure control valve ( 4 ) being connected between the priority pressure circuit (PK) and the secondary pressure circuit (SK) for limiting pressure (p_PK) of the priority circuit (PK), a pressure return ( 5 ) being located downstream of the output ( 24 ) of the variable displacement pump ( 2 ) and directing the hydraulic pressure (p_B) to the adjustment device ( 3 ), the hydraulic pressure (p_B) being adjustable along the pressure return ( 5 ) for adjusting the output of the variable displacement pump ( 2 ) as a function of the operating state of the transmission device, the method comprising the steps of:
 adjusting the hydraulic pressure (p_B), before changing the operating state of the transmission device, when the output of the variable displacement pump ( 2 ) needs to be increased relative to a current output of the variable displacement pump ( 2 ) in order to implement the change in the operating status of the transmission device.