Patent Publication Number: US-11384664-B2

Title: Vehicle oil supply mechanism

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 2019-087892 filed on May 7, 2019 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a technology to reduce a decrease in hydraulic pressure due to air suction in a vehicle oil supply mechanism configured to pump up oil via an oil strainer, the oil being accumulated in an oil pan. 
     2. Description of Related Art 
     In terms of a vehicle oil supply mechanism configured to pump up oil via an oil strainer, the oil being accumulated in an oil pan, such a situation is conceivable. That is, when an oil level of the oil thus accumulated in the oil pan inclines during turning traveling or hill-climbing traveling, for example, an inlet of the oil strainer partially appears from the oil level. At this time, there is such a risk that hydraulic pressure of the oil decreases due to occurrence of air suction and mixing of a large amount of air into the oil. The air suction is a phenomenon that the air is sucked in through the inlet of the oil strainer. In terms of this, as described in Japanese Unexamined Utility Model Application Publication No. 5-75414 (JP 5-75414 U), for example, in a structure in which a plurality of oil transmission holes is formed in a peripheral wall of an oil suction filter formed in a cylindrical shape, when an oil level of oil accumulated in an oil pan inclines, the oil transmission holes gradually communicate with air. This restrains suction of a large amount of air, and thus, it is considered that a sudden decrease in hydraulic pressure can be restrained. 
     SUMMARY 
     However, in the case of the structure described in JP 5-75414 U, the oil transmission holes are formed over the entire oil suction filter. Accordingly, there is such a risk that air suction occurs under all traveling conditions in which an oil level of oil inclines, the traveling conditions including turning traveling, hill-climbing traveling, and so on. Here, at the time of heavy load traveling such as hill-climbing traveling, it is necessary to set hydraulic pressure of the oil to be high. However, in the structure described in JP 5-75414 U, when the air is gradually sucked into an oil strainer along with inclination of the oil level of the oil, there is such a risk that the oil does not increase to target hydraulic pressure and driving performance of the vehicle decreases. 
     The present disclosure has been achieved in view of the above circumstances as a background, and an object of the present disclosure is to provide a structure that can reduce a decrease in hydraulic pressure of oil due to air suction in an oil strainer at the time of heavy load traveling in terms of a vehicle oil supply mechanism including an oil pan in which the oil is accumulated, and the oil strainer. 
     A first aspect of the present disclosure relates to a vehicle oil supply mechanism including an oil pan and an oil strainer. In the oil pan, oil is accumulated. The oil strainer is provided inside the oil pan. The oil strainer includes an inlet through which the oil is sucked in, and an air introduction hole having an aperture area smaller than that of the inlet. In an in-vehicle state, the air introduction hole is formed above the inlet in the vertical direction and is formed behind the inlet in the vehicle front-rear direction. 
     Further, a second aspect of the present disclosure is as follows. That is, in the vehicle oil supply mechanism of the first aspect, in the in-vehicle state, the air introduction hole may be formed within a range where the inlet is formed in the vehicle width direction. 
     Further, a third aspect of the present disclosure is as follows. That is, in the vehicle oil supply mechanism of the second aspect, in the in-vehicle state, an upper part of the air introduction hole in the vertical direction may be inclined vertically upward toward the center of the air introduction hole in the vehicle width direction. 
     In the vehicle oil supply mechanism according to the first aspect, the air introduction hole having an aperture area smaller than that of the inlet is formed above the inlet in the vertical direction. Accordingly, when the oil level of the oil accumulated in the oil pan inclines during traveling, the air is sucked in through the air introduction hole before the air is sucked in through the inlet. Here, the aperture area of the air introduction hole is smaller than that of the inlet. Accordingly, an amount of the air to be sucked in through the air introduction hole is small as compared to a case where the air is sucked in through the inlet. Further, since the air is sucked in through the air introduction hole, a decrease in the oil level of the oil is restrained. This accordingly restrains suction of the air through the inlet. Hereby, in comparison with a case where the air is sucked in through the inlet, the amount of the air to be sucked into the oil strainer is reduced. This can reduce a decrease in hydraulic pressure of the oil. Further, during heavy load traveling such as hill-climbing traveling or acceleration traveling, the oil moves rearward in the vehicle front-rear direction. However, since the air introduction hole is formed behind the inlet in the vehicle front-rear direction in a vehicle, the air introduction hole sinks in the oil, thereby restraining the air from being sucked in through the air introduction hole. Accordingly, no air is sucked into the oil strainer, thereby making it possible to obtain high hydraulic pressure during heavy load traveling. 
     Further, in the vehicle oil supply mechanism according to the second aspect, the oil level of the oil inclines to right or left during turning traveling of the vehicle. However, since the air introduction hole is formed within the range where the inlet is placed in the vehicle width direction of the vehicle, the air is sucked in through the air introduction hole prior to the inlet during turning traveling. Hereby, during turning traveling, the air is sucked in through the air introduction hole. This accordingly restrains suction of the air through the inlet. Accordingly, in comparison with a case where the air is sucked in through the inlet, it is possible to reduce a decrease in hydraulic pressure of the oil. 
     Further, in the vehicle oil supply mechanism according to the third aspect, in the in-vehicle state, the air introduction hole is inclined vertically upward toward the center of the air introduction hole in the vehicle width direction of the vehicle. Accordingly, even during turning traveling, the air is hardly sucked in through the air introduction hole at the time when the oil level of the oil inclines due to the turning traveling. Accordingly, even during turning traveling, the air is not sucked in through the air introduction hole under a predetermined traveling condition, thereby making it possible to restrain a decrease in hydraulic pressure of the oil due to suction of the air through the air introduction hole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is a schematic view of a vehicle to which the present disclosure is applied; 
         FIG. 2  illustrates an engine block constituting an engine in  FIG. 1  and a state inside an oil pan connected to a lower part of the engine block; 
         FIG. 3  illustrates a state inside the oil pan during counterclockwise turning traveling; 
         FIG. 4  is an enlarged view of an oil strainer in  FIG. 3 ; 
         FIG. 5  is an enlarged view of an air introduction hole in  FIG. 4 ; and 
         FIG. 6  is a view illustrating a state inside the oil pan during hill-climbing traveling. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present disclosure will hereinafter be described in detail with reference to the attached drawings. Note that the drawings are simplified or deformed appropriately in the following embodiment, and a scale ratio, a shape, and so on of each part are not necessarily drawn precisely. 
     Embodiment 
       FIG. 1  is a schematic view of a vehicle  10  to which the present disclosure is applied. The vehicle  10  includes an engine  12  as a driving force source, and a transaxle  18  configured to transmit power of the engine  12  to front wheels  16  via a pair of right and left axles  14 . The vehicle  10  is a vehicle of an FF type (front-engine, front-wheel drive type) in which the engine  12  and the transaxle  18  are arranged laterally on the front side of the vehicle. 
       FIG. 2  illustrates an engine block  20  constituting the engine  12  in  FIG. 1  and a state inside an oil pan  22  connected to a lower part of the engine block  20 .  FIG. 2  corresponds to a state (posture) of the engine block  20  and the oil pan  22  when the vehicle  10  is viewed from its right side. In  FIG. 2 , the upper side on the plane of paper corresponds to a vertically upper side, and the lower side on the plane of paper corresponds to a vertically lower side. Further, the right side on the plane of paper corresponds to the front side in the vehicle front-rear direction, and the left side on the plane of paper corresponds to the rear side in the vehicle front-rear direction. Note that  FIG. 2  illustrates a traveling state where the vehicle  10  is on a flat road surface, and no acceleration or deceleration is performed on the vehicle  10 . 
     As illustrated in  FIG. 2 , the oil pan  22  is connected to the lower part of the engine block  20  by bolts (not shown). The oil pan  22  is a member having a sagging shape and constituted by an iron plate member having a predetermined thickness. A predetermined amount of engine oil  24  (hereinafter referred to as the oil  24 ) is accumulated in the oil pan  22 , and the oil  24  is sucked up by an oil pump (not shown) and is supplied to each part of the engine  12 . 
     An oil strainer  26  is provided in a space of the oil pan  22  in which the oil  24  is accumulated. The oil strainer  26  is fixed to the engine block  20  by a bolt  28 . The oil strainer  26  is configured to remove foreign matter mixed in the oil  24  by use of a filter provided inside the oil strainer  26  when the oil  24  accumulated in the oil pan  22  is sucked up by an oil pump (not shown) driven by the engine  12 . A vehicle oil supply mechanism  40  configured to supply the oil  24  to each part of the engine  12  includes the oil pan  22  and the oil strainer  26 . 
     In an in-vehicle state illustrated in  FIG. 2 , an oil inlet  30  via which the oil  24  is sucked in is formed in a lower part of the oil strainer  26  in the vertical direction. The oil inlet  30  is formed at a position of the lower part of the oil strainer  26  in the vertical direction so that the oil inlet  30  sinks in the oil  24  in a traveling state where no acceleration or deceleration is performed on a flat road surface. Note that the oil inlet  30  corresponds to an inlet in the present disclosure. 
     In the meantime, in the oil strainer  26 , when a rotation speed of the engine  12  becomes high during hill-climbing traveling, for example, the amount of the oil  24  sucked up by the oil pump increases, so that the height of an oil level of the oil  24  in the oil pan  22  is lowered. Further, when the oil level of the oil  24  inclines due to a gradient of the road surface, the oil inlet  30  partially appears from the oil level. This might cause such a risk that air suction occurs and a sudden decrease in hydraulic pressure occurs. The air suction is a phenomenon that a large amount of air is sucked into the oil strainer  26 . In order to prevent the air suction from the oil inlet  30 , it is conceivable to increase the oil amount of the oil  24  or to increase the depth of the oil pan  22 . However, this results in that the weight of the vehicle increases or the engine  12  is arranged at a high position, thereby causing a deterioration in fuel efficiency and a decrease in driving performance. 
     In order to solve such a problem, the oil strainer  26  has an air introduction hole  32  via which the air is sucked in prior to the oil inlet  30 . The air introduction hole  32  is a communication hole via which an external space of the oil strainer  26  communicates with an internal space of the oil strainer  26 . The air introduction hole  32  is formed at a position behind the oil inlet  30  in the vehicle front-rear direction in the vehicle  10 . Further, the air introduction hole  32  sinks in the oil  24  in a traveling state where no acceleration or deceleration is performed as illustrated in  FIG. 2 . Accordingly, in the state illustrated in  FIG. 2 , the air is not sucked in through the air introduction hole  32 . 
       FIG. 3  illustrates a state inside the oil pan  22  during counterclockwise turning traveling.  FIG. 3  corresponds to a view when the oil pan  22  is viewed from the rear side of the vehicle  10  in an in-vehicle state. In  FIG. 3 , the right side on the plane of paper corresponds to the right side of the vehicle  10 , and the left side on the plane of paper corresponds to the left side of the vehicle  10 . Further, in  FIG. 3 , the upper side on the plane of paper corresponds to the upper side in the vertical direction, and the lower side on the plane of paper corresponds to the lower side in the vertical direction. 
     In  FIG. 3 , the oil inlet  30  is formed in a vertically lower part of the oil strainer  26  and at a position within a range L in a direction of a vehicle width (hereinafter referred to as the vehicle width direction) of the vehicle  10 . Further, the air introduction hole  32  is formed in a wall placed on the rear side of the oil strainer  26  in the vehicle front-rear direction. The air introduction hole  32  is formed above the oil inlet  30  in the vertical direction. That is, the air introduction hole  32  is formed within the range L where the oil inlet  30  is placed in the vehicle width direction of the vehicle  10 . Accordingly, when the oil level of the oil  24  inclines during turning traveling of the vehicle, the air introduction hole  32  appears from the oil level of the oil  24  prior to the oil inlet  30 . As a result, the air is sucked in through the air introduction hole  32  prior to the oil inlet  30 . 
     For example, during counterclockwise turning traveling, as illustrated in  FIG. 3 , the oil  24  accumulated in the oil pan  22  deviates to the right side in the vehicle width direction. Accordingly, the height of the oil level of the oil from the bottom of the oil pan  22  becomes lower toward the left side in the vehicle width direction. At this time, as illustrated in  FIG. 3 , the air introduction hole  32  appears from the oil level of the oil  24 , so that the air is sucked in through the air introduction hole  32 . 
       FIG. 4  is an enlarged view of the oil strainer  26  in  FIG. 3 . A connecting portion  34  connected to the oil pump (not shown) is provided on the right side of the oil strainer  26  in the vehicle width direction. The oil inlet  30  is formed in the vertically lower part of the oil strainer  26 . The air introduction hole  32  is formed in a pentagonal shape. Further, the air introduction hole  32  is formed within the range L where the oil inlet  30  is formed in the vehicle width direction. 
     Here, an aperture area S of the air introduction hole  32  is smaller than an aperture area of the oil inlet  30 . The aperture area of the oil inlet  30  corresponds to an area of a part of the oil inlet  30  through which the oil  24  is sucked in, namely, an area when the oil strainer  26  is viewed from the vertically lower part in an in-vehicle state. Further, the aperture area S of the air introduction hole  32  corresponds to an area of the pentagonal shape forming the air introduction hole  32  illustrated in  FIG. 4 . 
     The aperture area S of the air introduction hole  32  is made smaller than the aperture area of the oil inlet  30 . Accordingly, an amount of the air to be sucked in through the air introduction hole  32  at the time when the air introduction hole  32  appears from the oil level of the oil  24  during turning traveling is small in comparison with a case where the air is sucked in through the oil inlet  30 . When a small amount of the air is sucked into the oil strainer  26  through the air introduction hole  32  during turning traveling as such, the amount of the air to be sucked into the oil strainer  26  is reduced. Also, when the air is sucked into the oil strainer  26  through the air introduction hole  32 , a decrease in hydraulic pressure of the oil  24  is relaxed, thereby restraining a sudden decrease in hydraulic pressure of the oil  24 . Further, when the air is sucked into the oil strainer  26  through the air introduction hole  32 , a suction amount of the oil  24  by the oil pump decreases, so that a decrease in the oil level of the oil  24  is also relaxed. This accordingly restrains the oil inlet  30  from appearing from the oil level of the oil, thereby restraining suction of the air through the oil inlet  30 . 
     Further, in the in-vehicle state, an upper part of the air introduction hole  32  in the vertical direction is inclined vertically upward toward the center of the air introduction hole  32  in the vehicle width direction of the vehicle  10 . More specifically, an inclined portion  36  (see  FIG. 5 ) is formed in the upper part of the air introduction hole  32  in the vertical direction. The inclined portion  36  inclines upward as it goes toward the right side in the vehicle width direction from a left end portion of the air introduction hole  32  in the vehicle width direction. Further, an inclined portion  38  (see  FIG. 5 ) is formed in the upper part of the air introduction hole  32  in the vertical direction. The inclined portion  38  inclines upward as it goes toward the left side in the vehicle width direction from a right end portion of the air introduction hole  32  in the vehicle width direction. In the vicinity of the center of the air introduction hole  32  in the vehicle width direction, the inclined portions  36 ,  38  are connected to each other. Hereby, a central part of the air introduction hole  32  in the vehicle width direction projects upward in the vertical direction. 
     Respective inclinations of the inclined portion  36  and the inclined portion  38  that are formed in the upper part of the air introduction hole  32  in the vertical direction are formed to match the inclination of the oil level of the oil  24  during turning traveling of the vehicle.  FIG. 5  is an enlarged view of the air introduction hole  32  in  FIG. 4 . In  FIG. 5 , OL 1  to OL 3  indicate oil levels of the oil  24  in different traveling states during counterclockwise turning traveling. 
     For example, during counterclockwise turning traveling, in a state of the oil level OL 1  of the oil  24 , the whole air introduction hole  32  sinks in the oil  24 . At this time, the air is not sucked in through the air introduction hole  32 . In the meantime, when the oil level of the oil  24  further inclines and the oil  24  reaches the oil level OL 2 , the oil level of the oil  24  is along the inclined portion  36  of the air introduction hole  32 . When the oil level of the oil  24  still further inclines and the oil  24  reaches the oil level OL 3 , the air introduction hole  32  partially becomes higher than the position of the oil level of the oil  24 . At this time, the air is sucked in through a part of the air introduction hole  32 , the part being placed above the oil level of the oil  24 . 
     Even during turning traveling of the vehicle, it is desired that no air be sucked in through the air introduction hole  32 . In this respect, as the vertically upper part of the air introduction hole  32  is inclined, even during counterclockwise turning traveling, no air is sucked in through the air introduction hole  32  until the oil  24  reaches the oil level OL 2 . Since the vertically upper part of the air introduction hole  32  is inclined as such, no air is sucked in through the air introduction hole  32  until the inclination of the oil level of the oil reaches the oil level OL 2  even during counterclockwise turning traveling. Accordingly, the air is hardly sucked in through the air introduction hole  32  even during counterclockwise turning traveling. Note that,  FIG. 5  illustrates an aspect during counterclockwise turning traveling. However, since the inclined portion  38  is formed, the air is also hardly sucked in through the air introduction hole  32  during clockwise turning traveling. Further, the positions where the inclined portions  36 ,  38  of the air introduction hole  32  are formed, respective inclinations (shapes) of the inclined portions  36 ,  38 , and so on are set in advance through experiment or the like. The positions, the inclinations, and so on of the inclined portions  36 ,  38  are set such that the air introduction hole  32  sinks in the oil until the inclination of the oil level of the oil exceeds a predetermined value in case of quick turning traveling or the like. 
       FIG. 6  illustrates a state inside the oil pan  22  during hill-climbing traveling. Similarly to  FIG. 2 ,  FIG. 6  corresponds to a state when the vehicle  10  is viewed from the right side in the in-vehicle state. In  FIG. 6 , the right side on the plane of paper corresponds to the front side in the vehicle front-rear direction, the left side on the plane of paper corresponds to the rear side in the vehicle front-rear direction, the upper side on the plane of paper corresponds to the upper side in the vertical direction, and the lower side on the plane of paper corresponds to the lower side in the vertical direction. As illustrated in  FIG. 6 , during hill-climbing traveling, the engine block  20  and the oil pan  22  incline in accordance with the gradient of the road surface as compared with those in  FIG. 2 . At this time, the oil  24  deviates to the rear side in the vehicle front-rear direction, so that the height of the oil level from the bottom of the oil pan  22  becomes higher toward the rear side in the vehicle front-rear direction. Accordingly, the air introduction hole  32  placed on the rear side of the oil strainer  26  in the vehicle front-rear direction in the vehicle  10  sinks in the oil  24 . From this point, during hill-climbing traveling, the air introduction hole  32  sinks in the oil, so that no air is sucked into the oil strainer  26  through the air introduction hole  32 . 
     During hill-climbing traveling, a load applied to the engine  12  is large, and therefore, it is preferable that hydraulic pressure of the oil  24  pumped up by the oil pump do not decrease. In this respect, during hill-climbing traveling, the air introduction hole  32  sinks in the oil as illustrated in  FIG. 6 . As a result, no air is sucked in through the air introduction hole  32 , so that a decrease in hydraulic pressure of the oil  24  is restrained. 
     Further, during acceleration traveling of the vehicle  10 , a relative position between the position of the oil level of the oil  24  and the oil strainer  26  is generally the same as that in  FIG. 6 . That is, the oil  24  moves rearward in the vehicle front-rear direction as the vehicle  10  is accelerated. Accordingly, also during acceleration traveling, the air introduction hole  32  formed in the oil strainer  26  sinks in the oil as illustrated in  FIG. 6 . During acceleration traveling, a load applied to the engine  12  is large, and therefore, it is preferable that hydraulic pressure of the oil  24  pumped up by the oil pump do not decrease. In this respect, during acceleration traveling, the air introduction hole  32  sinks in the oil. As a result, no air is sucked in through the air introduction hole  32 , so that a decrease in hydraulic pressure of the oil  24  is restrained. 
     As described above, in the present embodiment, the air introduction hole  32  having an aperture area smaller than that of the oil inlet  30  is formed above the oil inlet  30  in the vertical direction. Accordingly, when the oil level of the oil  24  accumulated in the oil pan  22  inclines during traveling, the air is sucked in through the air introduction hole  32  before the air is sucked in through the oil inlet  30 . Here, the aperture area of the air introduction hole  32  is smaller than that of the oil inlet  30 . Accordingly, the amount of the air to be sucked in through the air introduction hole  32  is small as compared to a case where the air is sucked in through the oil inlet  30 . Further, since the air is sucked in through the air introduction hole  32 , a decrease in the oil level of the oil  24  is restrained. This accordingly restrains suction of the air through the oil inlet  30 . Hereby, in comparison with a case where the air is sucked in through the oil inlet  30 , the amount of the air sucked into the oil strainer  26  is reduced. This can reduce a decrease in hydraulic pressure of the oil  24 . 
     Further, during heavy load traveling such as hill-climbing traveling or acceleration traveling, the oil  24  moves rearward in the vehicle front-rear direction. However, since the air introduction hole  32  is formed behind the oil inlet  30  in the vehicle front-rear direction in the vehicle  10 , the air introduction hole  32  sinks in the oil  24 , thereby restraining the air from being sucked in through the air introduction hole  32 . Accordingly, no air is sucked into the oil strainer  26 , thereby making it possible to obtain high hydraulic pressure during heavy load traveling. In this respect, since it is not necessary to increase an oil amount of the oil  24 , deterioration in fuel efficiency is restrained. Further, warming-up performance also improves because the oil amount of the oil  24  does not increase. Further, as it is not necessary to increase the depth of the oil pan  22 , it is not necessary to set an arrangement position of the engine  12  to be high. As a result, it is possible to restrain a decrease in driving performance. 
     Further, according to the present embodiment, the oil level of the oil  24  inclines to right or left during turning traveling of the vehicle  10 . However, since the air introduction hole  32  is formed within the range where the oil inlet  30  is placed in the vehicle width direction of the vehicle  10 , the air is sucked in through the air introduction hole  32  prior to the oil inlet  30  during turning traveling. Hereby, during turning traveling, the air is sucked in through the air introduction hole  32 . This accordingly restrains suction of the air through the oil inlet  30 . Accordingly, in comparison with a case where the air is sucked in through the oil inlet  30 , it is possible to reduce a decrease in hydraulic pressure of the oil  24 . Further, in the in-vehicle state, the air introduction hole  32  is inclined vertically upward toward the center of the air introduction hole  32  in the vehicle width direction of the vehicle  10 . Accordingly, even during turning traveling, the air is hardly sucked in through the air introduction hole  32  at the time when the oil level of the oil  24  inclines due to the turning traveling. Accordingly, even during turning traveling, the air is not sucked in through the air introduction hole  32  under a predetermined traveling condition. This restrains a decrease in hydraulic pressure of the oil due to suction of the air through the air introduction hole  32 . 
     The embodiment of the present disclosure has been described in detail with reference to the drawings, but the present disclosure is also applied to other aspects. 
     For example, in the above embodiment, the air introduction hole  32  is formed in the oil strainer  26  arranged inside the engine  12  that is an internal combustion engine. However, the present disclosure is not necessarily limited to the engine  12 . For example, an air introduction hole may be formed in an oil strainer arranged inside a transmission. In short, the present disclosure can be applied appropriately to a configuration including an oil strainer provided inside an oil pan in a vehicle. 
     Further, in the above embodiment, the air introduction hole  32  is formed in a pentagonal shape. However, the air introduction hole  32  is not necessarily limited to the pentagonal shape. For example, the air introduction hole may be formed in a triangular shape. Further, an upper end of the air introduction hole  32  in the vertical direction has a pointed shape. However, the upper end of the air introduction hole  32  does not necessarily have a pointed shape. The upper end portion of the air introduction hole may be formed in parallel to the vehicle width direction. 
     Further, in the above embodiment, the vehicle  10  is an FF-type vehicle that uses the engine  12  as a driving source. However, the present disclosure is not necessarily limited to the above aspect. For example, the present disclosure is also applicable to a hybrid vehicle. In short, the present disclosure is applicable appropriately to a vehicle including a vehicle oil supply mechanism configured to suck up oil via an oil strainer, the oil being accumulated in an oil pan. 
     Note that the above descriptions are merely one embodiment to the utmost, and the present disclosure can be performed in an embodiment to which various changes and improvements are added based on the knowledge of a person skilled in the art.