Patent Publication Number: US-2015086393-A1

Title: Oil pump for vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority of Korean Patent Application Number 10-2013-0112835 filed Sep. 23, 2013, the entire contents of which application is incorporated herein for all purposes by this reference. 
     BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to an oil pump for a vehicle, and more particularly, to an oil pump for a vehicle, in which a low pressure discharge oil pump and a high pressure discharge oil pump are serially connected, and which includes one oil inlet, and one low pressure outlet and one high pressure outlet. 
     2. Description of Related Art 
     An oil pump is used for lubricating a transmission or supplying working oil of a transmission of a vehicle in the related art. 
     Oil with low pressure in a level of 2 to 4 bars is sufficient to lubricate or cool internal operational components of a transmission of a vehicle, for example, an automatic transmission, but in order to operate an operational component, for example, a clutch, of the automatic transmission, oil with high pressure in a level of 15 to 20 bars is required. 
     Accordingly, as illustrated in  FIG. 1 , in order to supply necessary oil to an automatic transmission  10 , each of a first oil pump  20  for low pressure discharge and a second oil pump  30  for high pressure discharge are mounted in the automatic transmission  10  in the related art. 
     The first oil pump  20  for low pressure discharge is formed of, for example, a mechanical oil pump, and the second oil pump  30  for high pressure discharge is formed of an electric oil pump. 
     The first oil pump  20  for low pressure discharge and the second oil pump  30  for high pressure discharge are connected with an oil storage  40  as illustrated in  FIG. 2 , so that the first oil pump  20  for low pressure discharge and the second oil pump  30  for high pressure discharge form necessary oil pressure by taking in the oil stored in the oil storage  40  through the respective inlets, and supplying the oil into the automatic transmission  10  through the respective outlets. 
     That is, the oil pump for the automatic transmission according to the related art has a dual structure of the low pressure discharge pump and the high pressure discharge pump. 
     However, the aforementioned structure of the oil pump for the automatic transmission for the vehicle in the related art has a drawback in an aspect of a layout because each of the low pressure discharge pump  20  and the high pressure discharge pump  30  need to be mounted in the automatic transmission  10 . 
     Further, two additional oil intake lines, which are separated from each other, are required in order for the low pressure discharge pump  20  and the high pressure discharge pump  300  to take in oil from the oil storage  40 , so that it is difficult to secure a layout, and each of the low pressure discharge pump  20  and the high pressure discharge pump  300  forms necessary pressure to discharge oil, so that in a case where high pressure is required, a load applied to the oil pump is increased, thereby increasing power loss. 
     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 pump for a vehicle, which is capable of decreasing power loss of the oil pump, has improved high pressure response, is compact and is decreased in a size to have an advantageous layout. 
     Various aspects of the present invention provide for an oil pump for a vehicle, including: a first oil pump configured to pressurize oil and discharge the pressurized oil; a second oil pump connected with the first oil pump so as to be operated by receiving power from the first oil pump, and configured to pressurize oil and discharge the pressurized oil; and a connection path configured to connect the second oil pump to the first oil pump in order to supply the oil discharged from the second oil pump to the first oil pump. 
     The first oil pump may be an oil pump for high pressure discharge for discharging relatively higher pressure oil than that of the second oil pump, and the second oil pump may be an oil pump for low pressure discharge for discharging relatively lower pressure oil than that of the first oil pump. 
     The second oil pump may be communicatively connected with an oil storage for taking in oil. 
     The oil pump for lower pressure discharge may include a low pressure oil discharge path for supplying the pressurized oil to the outside, and the connection path may be branched from the low pressure oil discharge path to be connected with the oil pump for high pressure discharge. 
     Each of the first oil pump and the second oil pump may be connected to the automatic transmission so as to supply the oil to the automatic transmission. 
     The first oil pump may include a driving shaft rotating by receiving power from the outside. 
     The second oil pump may include a driven shaft integrally and rotatably connected with the driving shaft in series. 
     Various aspects of the present invention provide for an oil pump for the vehicle including the oil pump for lower pressure discharge and the oil pump for high pressure discharge inside one oil pump housing to be configured to be compact, so that it is possible to decrease a size of the oil pump to achieve an advantageous layout. 
     The necessary quantity of oil in a low pressure side may be discharged by using the quantity of oil taken in by the oil pump for lower pressure discharge, and some of the oil boosted with the low pressure may be supplied to the oil pump for high pressure discharge through the connection path and may be boosted to high pressure to be discharged, so that it is possible to decrease a driving loss of the oil pump for boosting the pressure of the oil. 
     The oil pump for low pressure discharge and the oil pump for high pressure discharge may be serially connected with each other to be driven with the same number of times of rotation, so that it is possible to continuously and stably generate the quantity of discharged oil of each oil pump, and the quantity of oil supplied to the oil pump for high pressure discharge through a connection path from the oil pump for lower pressure discharge is stably maintained, thereby improving high pressure response. 
     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 an exploded perspective view of an oil pump for low pressure discharge and an oil pump for high pressure discharge mounted in an automatic transmission for a vehicle according to the related art. 
         FIG. 2  is a schematic diagram describing an operation of the oil pump for low pressure discharge and the oil pump for high pressure discharge according to the related art 
         FIG. 3  is a cross-sectional view of an exemplary oil pump for a vehicle 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. 
     An oil pump for a vehicle according to various embodiments of the present invention may be used for supplying low pressure oil for lubricating or cooling an inside of an automatic transmission mounted in a vehicle, or supplying high pressure oil serving as working oil pressure of an operational component, such as a clutch or a brake of the automatic transmission. 
     Referring to  FIG. 3 , the oil pump for the vehicle according to various embodiments of the present invention may include a housing  100  having a volume with a predetermined size therein. 
     A driving shaft  110  capable of rotating by receiving power through a power source, such as an engine or a motor, may be mounted at one side of the housing  100  to be ratably supported, and may be mounted to pass through the one side to protrude toward an inside of the housing  100 . 
     An oil pump  120  for high pressure discharge may be integrally and rotatably mounted to the driving shaft  110 . 
     The oil pump for high pressure discharge may be integrally and rotatably mounted to the driving shaft  110  to include an oil carrying member  122 , such as a rotor or a gear, pressurizing and discharging oil while rotating according to the rotation of the driving shaft  110 . 
     A driven shaft  130  may be integrally and rotatably connected to the driving shaft  110  in series. One will appreciate that such integral components may be monolithically formed. 
     The driven shaft  130  may be rotatably supported inside the housing  100 . 
     An oil pump  140  for low pressure discharge may be integrally and rotatably mounted on the driven shaft  130 . 
     The oil pump  140  for low pressure discharge may be integrally and rotatably mounted on the driven shaft  130  to include an oil carrying member  142 , such as a rotor or a gear, pressurizing and discharging oil while rotating according to the rotation of the driven shaft  130 . 
     An oil intake path  102  communicating with the oil pump  140  for low pressure discharge may be provided at the housing  100 . 
     The oil intake path  102  may be elongated from one external surface of the housing  100  to the oil pump  140  of the low pressure discharge. 
     An entrance of the oil intake path  102  may be connected with an oil storage  150  capable of storing the predetermined volume of oil. 
     Accordingly, when the oil pump  140  for the low pressure discharge is operated, the oil stored in the oil storage  150  is taken in up to the oil pump  140  for low pressure discharge through the oil intake path  102 . 
     A low pressure oil discharge path  104  for supplying the oil discharged from the oil pump  140  for low pressure discharge to the outside may be provided at the housing  100 . 
     The low pressure oil discharge path  104  may be formed of an additional line separated from the oil intake path  102  in the housing  100 . 
     The low pressure oil discharge path  104  may be elongated from the oil pump  140  for low pressure discharge to one external surface of the housing  100 . 
     An outlet of the low pressure oil discharge path  104  is communicatively connected with, for example, the inside of the automatic transmission, so that the low pressure oil discharged through the low pressure oil discharge path  104  is supplied to the inside of the automatic transmission to be usable for lubricating or cooling the operational components of the automatic transmission. 
     A connection path  106  communicating with the low pressure oil discharge path  104  may be formed at a partial section of the low pressure oil discharge path  104 . 
     One end of the connection path  106  may be formed to communicate with the low pressure oil discharge path  104 , but the other end of the connection path  106  may be elongated to communicate with the oil pump  120  for high pressure discharge. 
     Accordingly, the low pressure oil discharged from the oil pump  140  for low pressure discharge is supplied to the automatic transmission through the low pressure oil discharge path  104 , and some of the low pressure oil discharged from the oil pump  140  for low pressure discharge is supplied to the oil pump  120  for high pressure discharge through the connection path  106  to be boosted in the oil pump  120  for high pressure discharge again. 
     In order to supply the high pressure oil discharged from the oil pump  120  for high pressure discharge may be elongated from the oil pump  120  for high pressure discharge to one external surface of the housing  100 . 
     An outlet of the high pressure oil discharge path  108  is communicatively connected with, for example, the inside of the automatic transmission, so that the high pressure oil discharged through the high pressure oil discharge path  108  is supplied to the inside of the automatic transmission to be usable for operating the operational components of the automatic transmission, for example, a clutch or a brake. 
     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.