Abstract:
An oil supply system may include a first hydraulic pump pumping oil to a low pressure portion through a first main line, a second hydraulic pump pumping oil to a high pressure portion through a second main line, first and second check valves that are respectively disposed at one side of the first and second main lines, a first convert valve supply the oil flowing the second main line to the low pressure portion depending on the pressure of oil that is transferred from a front side of the first check valve of the first main line, and a second convert valve supplying oil flowing the first main line to the high pressure portion depending on the pressure of oil that is transferred from a front side of the second check valve of the second main line.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority of Korean Patent Application Number 10-2013-0052729 filed May 9, 2013, the entire contents of which application is incorporated herein for all purposes by this reference. 
     BACKGROUND OF INVENTION 
     Field of Invention 
     The present invention relates to an oil supply system that securely supplies a low pressure portion for lubricating a component and a high pressure portion for operating elements a clutch and a brake with oil. 
     Description of Related Art 
     Generally, because an engine of an electric vehicle stops its operating during a low speed condition or a stop condition, a motorized hydraulic pump is provided in the electric vehicle instead of a mechanical hydraulic pump. 
     And, a hybrid vehicle can use a mechanical hydraulic pump and a motorized hydraulic pump, and there is a document as a conventional art, Korean patent application No. 10-2008-0123014 that describes a mechanical hydraulic pump and a hydraulic pump. 
     A motorized hydraulic pump is gradually used instead of a mechanical hydraulic pump, and when two motorized hydraulic pumps are used in a vehicle, one is used to supply a low pressure portion with oil and the other is used to supply a high pressure portion with oil. 
     Here, the low pressure portion uses low pressure oil to lubricate components and the high pressure portion uses high pressure oil to operate elements such as a clutch and a brake. 
     Meanwhile, while two hydraulic pumps are used to supply the low pressure portion and the high pressure portion with oil, if a pump for a low pressure oil or a pump for a high pressure oil cannot be operated, the oil cannot securely supplied to the low pressure portion or the high pressure portion. 
     The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY 
     Various aspects of the present invention provide for an oil supply system having advantages of securely supplying a low pressure portion and a high pressure portion with oil through two motorized hydraulic pump. 
     An oil supply system according to various aspects of the present invention may include a first hydraulic pump that is configured to pump oil to a low pressure portion through a first main line, a second hydraulic pump that is configured to pump oil to a high pressure portion through a second main line, a first and second check valve that is respectively disposed at one side of the first main line and the second main line, a first convert valve that is configured to make the oil flowing the second main line be supplied to the low pressure portion depending on the pressure of oil that is transferred from a front side of the first check valve of the first main line, and a second convert valve that is configured to make the oil flowing the first main line be supplied to the high pressure portion depending on the pressure of oil that is transferred from a front side of the second check valve of the second main line. 
     A first control port of the first convert valve may be connected to the first main line through a first valve operating line, and one side thereof may be connected to the second main line through a high pressure oil supply line, and the other side may be connected to the first main line through a first emergency line. 
     One side end portion of the high pressure oil supply line may be connected to the first convert valve, and the other side end portion thereof may be connected to a rear side of the second check valve of the second main line. 
     The first emergency line may be connected to a rear side of the first check valve of the first main line. 
     A second control port of the second convert valve may be connected to the second main line through a second valve operating line, and one side thereof may be connected to the first main line through a low pressure oil supply line, and the other side thereof may be connected to the second main line through a second emergency line 
     One side end portion of the low pressure oil supply line may be connected to the first convert valve, and the other side end portion thereof may be connected to a rear side of the first check valve of the first main line. 
     The second emergency line may be connected to a rear end portion of the second check valve of the second main line. 
     The low pressure portion may be connected to a lubrication portion for lubricating a component. 
     The high pressure portion may include a hydraulic pressure clutch and a hydraulic pressure brake. 
     An oil supply system according to various aspects of the present invention may include a first hydraulic pump that pumps oil to a low pressure portion through a first main line, a second hydraulic pump that pumps oil to high pressure portion through a second main line, a first convert valve that makes oil flowing the second main line be selectively supplied to the low pressure portion depending on the pressure of oil that is transferred from the first main line, and a second convert valve that makes oil flowing the first main line be selectively supplied to the high pressure portion depending on the pressure of oil that is transferred from the second main line. 
     The oil supply system may include a first and second check valve that is respectively disposed on the first main line and the second main line to prevent counter flowing of oil, wherein the first convert valve is operated by the pressure of oil that is transferred from a front side of the first check valve of the first main line, and the second convert valve is operated by the pressure of oil that is transferred from a front side of the second check valve of the second main line. 
     As described above, in an oil supply system according to various aspects of the present invention, when one of a first hydraulic pump for pumping oil to a low pressure portion and a second hydraulic pump for pumping oil to a high pressure portion is not operated, oil that is pumped by the other pump is securely supplied to the low pressure portion and the high pressure portion. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an exemplary oil supply system according to the present invention. 
         FIG. 2  is a schematic diagram showing an exemplary condition in which a first hydraulic pump does not operate in an oil supply system according to the present invention. 
         FIG. 3  is a schematic diagram showing an exemplary condition in which a second hydraulic pump operates in an oil supply system according to the present invention. 
         FIGS. 4, 5, 6 and 7  are flowcharts showing exemplary routes in which oil is supplied by the operation of first and second convert valves in an oil supply system according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
       FIG. 1  is a schematic diagram of an oil supply system according to various embodiments of the present invention. 
     Referring to  FIG. 1 , an oil supply system includes a low pressure oil supply system and a high pressure oil supply system, the low pressure oil supply system includes a first hydraulic pump  100 , a first regulator valve  120 , a low pressure portion  130 , a lubrication portion  140 , a first main line  110 , a first check valve  160 , a first convert valve  150 , a first valve operating line  170 , a high pressure oil supply line  180 , and a first emergency line  190 . 
     The high pressure oil supply system includes a second hydraulic pump  105 , a second regulator valve  125 , a high pressure portion  135 , an operating element  145 , a second main line  115 , a second check valve  165 , a second convert valve  155 , a second valve operating line  175 , a low pressure oil supply line  185 , and a second emergency line  195 . 
     The first main line  110  connects the first hydraulic pump  100  with the lubrication portion  140  as the low pressure portion  130 , and the first check valve  160  and the first regulator valve  120  are sequentially disposed on the first main line  110 . 
     The first hydraulic pump  100  and the second hydraulic pump  105  pumps oil from one oil pan to pump oil to the low pressure portion  130  and the high pressure portion  135 . 
     More specifically, the first valve operating line  170  is diverged from a front side of the first check valve  160  of the first main line  110  to be connected to the first convert valve  150 . Also, the high pressure oil supply line  180  is diverged from a rear side of the second check valve  165  of the second main line  115  to be connected to the first convert valve  150 . And, the first emergency line  190  is formed from the first convert valve  150  to a rear side of the first check valve  160  of the first main line  110 . 
     The second main line  115  connects the second hydraulic pump  105  with the operating element  145  as the high pressure portion  135 , and the second check valve  165  and the second regulator valve  125  are sequentially disposed on the second main line  115 . 
     The second valve operating line  175  is diverged from a front side of the second check valve  165  of the second main line  115  to be connected to the second convert valve  155 . 
     Also, the low pressure oil supply line  185  is diverged from a rear side of the first check valve  160  of the first main line  110  to be connected to the second convert valve  155 . And, the second emergency line  195  is formed from the second convert valve  155  to a rear side of the second check valve  165  of the second main line  115 . 
     In various embodiments of the present invention, if oil pressure is not transferred from the first hydraulic pump  100  through the first valve operating line  170 , the first convert valve  150  receives oil that is pumped from the second hydraulic pump  105  through the high pressure oil supply line  180  and supplies the first main line  110  with this through the first emergency line  190 . 
     And, if oil pressure is transferred from the second hydraulic pump  105  through the second valve operating line  175 , the second convert valve  155  receives oil that is pumped by the first hydraulic pump  100  through the low pressure oil supply line  185  and supplies the second main line  115  with this through the second emergency line  195 . 
       FIG. 2  is a schematic diagram showing a condition in which a first hydraulic pump does not operate in an oil supply system according to various embodiments of the present invention. 
     Referring to  FIG. 2 , if the first hydraulic pump  100  is not operated and the second hydraulic pump  105  is operated, oil pressure is not transferred to the first convert valve  150  through the first valve operating line  170 . 
     Accordingly, the first convert valve  150  supplies the first main line  110  with oil through the first emergency line  190 , wherein the oil is supplied from the second hydraulic pump  105  through the high pressure oil supply line  180 . 
       FIG. 3  is a schematic diagram showing a condition in which a second hydraulic pump operates in an oil supply system according to various embodiments of the present invention. 
     Referring to  FIG. 3 , if the first hydraulic pump  100  is operated and the second hydraulic pump  105  is not operated, oil pressure is not transferred to the second convert valve  155  through the second valve operating line  175 . 
     Accordingly, the second convert valve  155  supplies the second main line  115  with oil through the second emergency line  195 , wherein the oil is supplied from the first hydraulic pump  100  through the low pressure oil supply line  185 . 
       FIGS. 4 to 7  are flowchart showing a route that oil is supplied by the operation of the first and second convert valve in an oil supply system according to various embodiments of the present invention. 
     Referring to  FIG. 4 , the first control port  400  is formed on the first convert valve  150  and a first valve operating line  170  is formed to the first control port  400 . And, the high pressure oil supply line  180  is connected to one side of the first convert valve  150 , and the first emergency line  190  is connected to the other side thereof. 
     Here, if oil is transferred to the first control port  400  of the first convert valve  150  through the first valve operating line  170 , the high pressure oil supply line  180  and the first emergency line  190  is not connected. 
     Referring to  FIG. 5 , if the oil is not transferred to the first control port  400  of the first convert valve  150  through the first valve operating line  170 , the high pressure oil supply line  180  and the first emergency line  190  are connected such that the oil that is pumped by the second hydraulic pump  105  is transferred to the first regulator valve  120 . 
     Referring to  FIG. 6 , the second control port  600  is formed on the second convert valve  155 , and the second valve operating line  175  is connected to the second control port  600 . And, the low pressure oil supply line  185  is connected to one side of the second convert valve  155 , and the second emergency line  195  is connected to the other side thereof. 
     Here, if oil pressure is transferred to the second control port  600  of the second convert valve  155  through the second valve operating line  175 , the low pressure oil supply line  185  is disconnected with the second emergency line  195 . 
     Referring to  FIG. 7 , if oil pressure is not transferred to the second control port  600  of the second convert valve  155  through the second valve operating line  175 , the low pressure oil supply line  185  is connected with the second emergency line  195  such that the oil pumped by the first hydraulic pump  100  is supplied to the second regulator valve  125 . 
     In various embodiments of the present invention, the first convert valve  150  is operated when a pressure of oil that is supplied through the first valve operating line  170  is less than a predetermined value such that oil that is pumped by the second hydraulic pump  105  is supplied to the first main line  110  with through the high pressure oil supply line  180  and the first emergency line  190 . 
     Also, the second convert valve  155  is operated when a pressure of oil that is supplied through the second valve operating line  175  is less than a predetermined value such that oil that is pumped by the first hydraulic pump  100  is supplied to the second main line  115  through the low pressure oil supply line  185  and the second emergency line  195 . 
     For convenience in explanation and accurate definition in the appended claims, the terms front or rear, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.