JP2008051054A - Engine oil return structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the degree of freedom in layout of an oil return member returning oil separated from blowby gas to a space sandwiched between a balancer housing and an oil pan. <P>SOLUTION: The oil return member is composed by connecting an upper side member 54 having an oil inlet hole 54b connected to the oil return passage 20a of the balancer housing 19 and a lower side member 52 having an oil outlet hole 52e opened into oil in the oil pan, thereby the setting degree of freedom in the position of the oil outlet hole 52e can be improved. As a result, by arranging the oil outlet hole 52e to a position hardly influenced by oil suction negative pressure generated in the oil suction hole 52f of the oil strainer 51, gas-liquid separation between blowby gas and oil can be certainly carried out. Besides, since the lower side member 52 and upper side member 54 which are made from a metal mold-shaped article have a flexible shape, the oil outlet hole 52e is certainly positioned under an oil liquid level, and gas-liquid separation is prevented from being adversely affected by variations in pressure in a crank case. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine oil return structure in which an oil return member for returning oil separated from blow-by gas to an oil pan is disposed between an engine balancer housing and an oil pan.

  Since the blow-by gas leaking from the engine combustion chamber into the crankcase contains oil, the blow-by gas is separated into the intake system after separating the blow-by gas and oil in the gas-liquid separation chamber provided in the cylinder head. It is necessary to return the oil to the oil pan.

In an engine in which the balancer housing is supported on the lower surface of the lower block coupled to the lower end of the cylinder block, an oil return passage for returning oil from the gas-liquid separation chamber provided in the cylinder head to the oil pan is provided to The one formed inside is known from Patent Document 1 below.
JP 2003-201815 A

  By the way, in the above-mentioned conventional one, the oil outlet hole of the oil return passage is directly open on the lower surface of the balancer housing, and the oil outlet hole is adjacent to the oil suction hole of the oil strainer provided integrally with the balancer housing. Therefore, the suction negative pressure of the oil pump generated in the vicinity of the oil suction hole of the oil strainer acts on the oil outlet hole of the oil return passage, and the blow-by gas and oil are separated in the gas-liquid separation chamber. May have adverse effects.

  In order to eliminate this problem, the oil outlet hole of the oil return passage should be positioned away from the oil suction hole of the oil strainer. However, since the oil outlet hole opens directly on the lower surface of the balancer housing, its position It is difficult to choose freely.

  The present invention has been made in view of the above circumstances, and an object thereof is to increase the degree of freedom in disposing an oil return member that returns oil separated from blow-by gas to a space sandwiched between a balancer housing and an oil pan.

  In order to achieve the above object, according to the invention described in claim 1, an engine in which an oil return member for returning oil separated from blow-by gas to the oil pan is disposed between the balancer housing of the engine and the oil pan. The oil return member has an upper member made of a molded product in which an oil inlet hole connected to the oil return passage of the balancer housing is formed, and an oil outlet hole that opens into the oil of the oil pan. An oil strainer structure for an engine is proposed, which is constituted by combining a lower member made of a formed mold product.

  The upper second member 54 of the embodiment corresponds to the upper member of the present invention.

  According to the configuration of the first aspect, the upper member formed with the oil inlet hole connected to the oil return passage of the balancer housing is coupled to the lower member formed with the oil outlet hole opened in the oil of the oil pan. Since the oil return member is configured, the degree of freedom in setting the position of the oil outlet hole can be increased as compared with the case where the oil outlet hole is directly formed in the balancer housing. As a result, by arranging the oil outlet hole at a position that is not easily affected by the negative suction pressure of the oil generated in the oil suction hole of the oil strainer disposed inside the oil pan, the gas-liquid between the blow-by gas and the oil Separation can be ensured. In addition, since the lower and upper members made of mold products have a high degree of freedom in shape, the oil outlet hole is surely positioned below the oil level of the oil pan, and the crankcase pressure fluctuation adversely affects gas-liquid separation. Can be prevented.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 9 show a first embodiment of the present invention. FIG. 1 is a front view of the engine, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a line 3-3 of FIG. 4 is a sectional view taken along line 4-4 in FIG. 2, FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, FIG. 6 is a sectional view taken along line 6-6 in FIG. FIG. 8 is an exploded perspective view as seen from obliquely below, FIG. 8 is an exploded perspective view as seen from obliquely above the oil strainer, and FIG. 9 is a perspective view of a balancer device provided with an oil strainer.

  As is clear from FIGS. 1 and 2, the lower block 12 is fixed to the lower surface of the cylinder block 11 of the diesel engine E of the automobile, and the oil pan 13 for storing oil is fixed to the lower surface of the lower block 12. A balancer device 14 for reducing secondary vibration of the engine E is provided on the lower surface of the lower block 12, and the balancer device 14 is accommodated in an oil pan 13. A crankshaft 15 is rotatably supported between the cylinder block 11 and the lower block 12, and is provided at the shaft end of the drive sprocket 16 provided at the shaft end of the crankshaft 15 and the drive balancer shaft 29 of the balancer device 14. An endless chain 18 is wound around the driven sprocket 17.

  As apparent from FIGS. 3 to 6, the balancer housing 19 of the balancer device 14 is composed of an upper housing 20 and a lower housing 21 which are divided into upper and lower parts by a plurality of bolts 22. The housing 23 is coupled by a plurality of bolts 24... And the left side housing 25 is coupled by a plurality of bolts 26. The balancer housing 19 is fixed to the lower surface of the lower block 12 by two bolts 27 and 27 that pass through the upper housing 20 and the lower housing 21 and two bolts 28 and 28 that pass through the right side housing 23.

  A drive balancer shaft 29 and a driven balancer shaft 30 are supported in parallel on the balancer housing 19. The driven balancer shaft 29 has a driven sprocket 17, a drive gear 31, and a first balancer weight from one end side to the other end side. 32 and a second balancer weight 33 are provided. The driven balancer shaft 30 is provided with a driven gear 34, a first balancer weight 35, and a second balancer weight 36 from one end side to the other end side. An endless chain 18 is wound around the drive sprocket 16 provided on the crankshaft 15 and the driven sprocket 17 provided on the drive balancer shaft 29. The drive gear 31 provided on the drive balancer shaft 29 meshes with the driven gear 34 provided on the driven balancer shaft 30.

  Accordingly, the rotation of the crankshaft 15 is transmitted to the drive balancer shaft 29 through the drive sprocket 16, the endless chain 18 and the driven sprocket 17 by the operation of the engine E, and the rotation of the drive balancer shaft 29 is transmitted to the drive gear 31 and the driven gear 34. To the driven balancer shaft 30. At this time, the number of teeth of the drive sprocket 16 of the crankshaft 15 is set to twice the number of teeth of the driven sprocket 17 of the drive balancer shaft 29, and the number of teeth of the drive gear 31 is set equal to the number of teeth of the driven gear 34. Therefore, the drive balancer shaft 29 and the driven balancer shaft 30 rotate in opposite directions at twice the number of rotations of the crankshaft 15, and the first and the second provided on the drive balancer shaft 29 and the driven balancer shaft 30. The secondary vibration of the engine E is reduced by the second balancer weights 32, 33;

  As clearly shown in FIG. 6, a circular pump chamber 23 a of an oil pump 37 formed of a trochoid pump is opened on a coupling surface of the right side housing 23 to the upper housing 20 and the lower housing 21, and the pump chamber 23 a The outer rotor 38 and the inner rotor 39 that mesh with each other are housed in a state of meshing with each other. The suction port 40 facing the pump chamber 23 a communicates with a suction passage 41 that opens on the lower surface of the lower housing 21. Further, the discharge port 42 facing the pump chamber 23 a communicates with a discharge passage 43 (see FIG. 3) opened on the upper surface of the right side housing 23 (see the connection surface with the lower block 12).

  Next, the structure of the oil strainer 51 that filters the oil drawn from the oil pan 13 into the oil pump 37 will be described with reference to FIGS.

  As is apparent from FIGS. 7 and 8, the oil strainer 51 includes a lower member 52, an upper first member 53 and an upper second member 54 that are injection-molded with a synthetic resin by a mold, and a strainer element made of a synthetic resin mesh. And a total of four members.

  The lower member 52 is a shallow container-like main body portion 52a that is curved in the shape of a ball and has an open upper surface, a plate-like support arm portion 52b that extends obliquely upward from a part of the outer periphery of the main body portion 52a, and a support arm A straight oil return passage forming portion 52c continuous with the upper end of the portion 52b and a pipe-shaped oil discharge pipe portion 52d extending downward from one end of the oil return passage forming portion 52c are provided. A rectangular oil suction hole 52f is opened on one end side (wide side) of the main body 52a, and a bowl-shaped groove 52g communicating with the oil discharge pipe 52d is formed on the upper surface of the oil return passage forming portion 52c. Is done. An oil outlet hole 52e opened at the lower end of the oil discharge pipe portion 52d is located below the surface of the oil stored in the oil pan 13, and the pressure fluctuation in the crankcase is sucked through the oil return passage connected to the cylinder head. It does not affect the system.

  The upper first member 53 is a member having substantially the same shape as the main body 52a of the lower member 52. The upper first member 53 is formed in a shallow container shape whose lower surface is open, and penetrates upward to the other end side (the narrow side). An oil discharge hole 53a is formed. In addition, mounting bosses 53b, 53c, 53d having bolt holes are projected at three locations on the outer periphery of the upper first member 53.

  The upper second member 54 is a member having substantially the same shape as the oil return passage forming portion 52c of the lower member 52, and has a bowl-shaped groove 54a opposed to the bowl-shaped groove 52g of the oil return passage forming portion 52c on the lower surface thereof. And an oil inlet hole 54b penetrating upward is formed at the end opposite to the oil discharge pipe 52d. Mounting bosses 54c and 54d having bolt holes are provided on both sides of the oil inlet hole 54b.

  Thus, the lower surface of the upper first member 53 and the lower surface of the upper second member 54 are joined to the upper surface of the main body portion 52a and the upper surface of the oil return passage forming portion 52c of the lower member 52 respectively by welding. The outer peripheral portion of the strainer element 55 is fixed between the lower surface of the upper first member 53 and the upper surface of the main body portion 52a of the lower member 52. As a result, the dirty chamber 56 is defined between the main body 52 a of the lower member 52 and the strainer element 55, and the clean chamber 57 is defined between the upper first member 53 and the strainer element 55. An oil return passage 58 is formed between the groove 52g of the oil return passage forming portion 52c of the lower member 52 and the groove 54a of the upper second member 54, and both ends of the oil return passage 58 are connected to the oil inlet hole 54b and the oil inlet passage 54b. The oil discharge pipe portion 52d communicates.

  Since the lower member 52, the upper first member 53, and the upper second member 54 of the oil strainer 51 are formed of a synthetic resin mold product, the design freedom of the shape can be increased, and the balancer housing 19 and the oil pan 13 can be increased. A compact and highly functional oil strainer 51 can be disposed in a narrow space between the two. In particular, with respect to the oil suction path to the oil pump 37, the oil suction hole 52f and the oil discharge hole 53a can be arranged at optimal positions, and a sufficient cross-sectional area of the oil flow path can be secured. The oil return path separated from the blow-by gas can be disposed so that the position of the oil outlet hole 52e is sufficiently separated from the oil suction port 52f of the oil strainer 51 and is not exposed on the oil level.

  As is apparent from FIG. 4, the oil strainer 51 configured in this way has three bolts 59 that penetrate the bolt holes of the three mounting bosses 53 b, 53 c, 53 d of the upper first member 53 from the bottom to the top. The upper portion of the balancer housing 19 is fastened to the lower housing 21 of the balancer housing 19 by two bolts 60, 60 that pass through the bolt holes of the two mounting bosses 54c, 54 of the upper second member 54 from the bottom up. Fastened to the housing 20. At this time, the two mounting bosses 54c and 54d of the upper second member 54 are fixed to the end portion of the upper housing 20 on the drive balancer shaft 29 side, and the two mounting bosses 53b and 53c of the upper first member 53 are lower. Since the remaining one mounting boss 53d of the upper first member 53 is fixed between the drive balancer shaft 29 and the driven balancer shaft 30 of the lower housing 21, the oil strainer is fixed to the driven balancer shaft 30 side of the housing 21. 51 is supported in a positional relationship so as to cover the lower surface of the lower housing 21.

  In this mounted state, the oil discharge hole 53a of the upper first member 53 communicates with the suction port 40 of the oil pump 37 via the suction passage 41 opened on the lower surface of the lower housing 21 (see FIG. 6). Further, the oil inlet hole 54 b of the upper second member 54 communicates with an oil return passage 23 b that opens to the coupling surface to the lower block 12 of the right side housing 23 via an oil return passage 20 a that opens to the lower surface of the upper housing 20. (See FIG. 9). The oil return passage 23b of the right side housing 23 is a labyrinth type gas-liquid separation chamber (not shown) formed in the cylinder head through an oil return passage (not shown) penetrating the inside of the lower block 12 and the cylinder block 11. ).

  Next, the operation of the first embodiment of the present invention having the above configuration will be described.

  When the engine E is operated, the rotation of the crankshaft 15 is transmitted to the drive balancer shaft 29 via the endless chain 18, and the rotation of the drive balancer shaft 29 is transmitted to the driven balancer shaft 30 via the drive gear 31 and the driven gear 34. As a result, the oil pump 37 connected to the driven balancer shaft 30 operates.

  As a result, the oil stored in the oil pan 13 is sucked from the oil suction hole 52 f of the lower member 52 of the oil strainer 51, filtered from the dirty chamber 56 through the strainer element 55, and then from the clean chamber 57 to the upper side. The oil passes through the oil discharge hole 53a of the first member 53, and is further drawn into the oil pump 37 through the suction passage 41 (see FIGS. 3 and 6) of the lower housing 21 of the balancer housing 19 and the suction port 40 of the right side housing 23. The

  The oil discharged to the discharge port 42 of the oil pump 37 is supplied to the lower block 12 from the discharge passage 43 (see FIG. 3) of the right side housing 23, and then branches to a plurality of paths from there to the journal portion of the crankshaft 15. And used for lubrication of valve mechanisms.

  At that time, the main body portion 52a and the upper second member 54 of the lower member 52 that define the dirty chamber 56 and the clean chamber 57 of the oil strainer 51 have a flat shape in the vertical direction, Since the outer peripheral portion of the large-area strainer element 55 is sandwiched and fixed, an increase in oil flow resistance due to the strainer element 55 can be minimized, and clogging of the strainer element 55 can be prevented.

  As is apparent from FIGS. 7 and 8, in order to avoid interference with the bottom surface of the oil pan 13, the oil strainer 51 is thin on the oil suction hole 52f side and thick on the oil discharge hole 53a side. By making the width of the oil strainer 51 wider on the oil suction hole 52f side and narrower on the oil discharge hole 53a side, it is possible to prevent an abrupt change in the oil cross-sectional area and minimize an increase in oil flow resistance. Yes. In particular, since the flow passage cross-sectional area of the oil strainer 51 is gradually narrowed from the oil suction hole 52f side toward the oil discharge hole 53a side, the flow rate of oil flowing from the oil suction hole 52f toward the discharge hole 53a is slowly increased. Thus, the inflow resistance to the oil pump 37 can be reduced.

  The blow-by gas leaking from the combustion chamber of the engine E is supplied to the cylinder head while containing oil. After being separated into blow-by gas and oil in the gas-liquid separation chamber provided there, the blow-by gas is returned to the intake system, and the oil is returned to the oil pan 13. The oil separated from the blow-by gas flows down in an oil return passage (not shown) formed in the cylinder block 11 and the lower block 12, and the oil return passage 23 b of the right side housing 23 of the balancer housing 19 coupled to the lower block 12. (See FIGS. 3 and 9) and the oil return passage 20a (see FIGS. 3 and 9) of the upper housing 20 and the oil inlet hole 54b (see FIGS. 8 and 8) of the upper second member 54 of the oil strainer 51. 9).

  The oil that has flowed into the oil inlet hole 54b of the upper second member 54 is the oil return passage 58 formed between the oil return passage forming portion 52c of the lower member 52 and the upper second member 54, and the oil of the lower member 52. It passes through the discharge pipe portion 52d and is returned from the oil outlet hole 52e below the oil level in the oil pan.

  As described above, the oil return passage 58 and the oil discharge pipe portion 52d for returning the oil after separating the blow-by gas to the oil pan 13 are formed integrally with the oil strainer 51. Compared to this, the number of parts and the number of assembly steps can be reduced.

  Further, a lower member 52 constituting a part of an oil strainer 51 for filtering the oil in the oil pan 19 and a lower member 52 constituting a part of an oil return member for returning the oil separated from the blow-by gas to the oil pan 19. Therefore, the total number of the four members when the members are not shared is suppressed to a total of three, and the number of parts and the cost of the oil strainer 51 and the oil return member can be reduced.

  Further, since the upper first member 53 and the upper second member 54 coupled to the balancer housing 19 are separate members, the upper first and second members 53 and 54 are improved in component accuracy to be coupled to the balancer housing 19. This makes it easy to suppress oil leakage from the coupling portion. If the upper first and second members 53 and 54 are configured as a single member, the size of the members increases, and it is necessary to form the oil discharge hole 53a and the oil inlet hole 54b in the same member. The dimensional accuracy for aligning the hole 53a and the oil inlet hole 54b with the suction passage 41 and the oil return passage 20a of the balancer housing 19 becomes strict, leading to an increase in processing cost.

  By the way, depending on the positional relationship between the oil suction hole 52f and the oil outlet hole 52e of the oil strainer 51, the suction negative pressure of the oil pump 37 acting on the oil suction hole 52f acts on the oil outlet hole 52e, and the oil outlet hole 52e. There is a possibility of adversely affecting the separation of blow-by gas and oil in the gas-liquid separation chamber connected to 52e. However, according to the present embodiment, the oil return passage 58 formed between the oil return passage forming portion 52c of the lower member 52 and the upper second member 54 can freely position the oil outlet hole 52e with respect to the oil suction hole 52f. Therefore, the influence of the suction negative pressure of the oil pump 37 can be avoided.

  Moreover, since the oil discharge pipe portion 52d protruding downward is formed in the lower member 52 and the oil outlet hole 52e is opened at the lower end thereof, the oil outlet hole 52e is reliably prevented from being exposed on the oil level. The crankcase pressure fluctuation can be prevented from adversely affecting the gas-liquid separation.

  The oil strainer 51 is supported so as to bridge both ends of the balancer housing 19, and partitions the space between the lower surface of the balancer housing 19 and the bottom surface of the oil pan 13. The function of the baffle plate that suppresses the fluctuation of the oil level accompanying the turning of the vehicle, the inclination of the road surface, etc. can be exhibited, and the air biting of the oil pump 37 due to the mixing of air into the oil can be reliably prevented. This eliminates the need to provide a special baffle plate or reduces the size of the existing baffle plate, thereby reducing the number of parts and the cost. In particular, since the support arm portion 52b that connects the main body portion 52a of the lower member 52 and the oil return passage forming portion 52c is formed in a plate shape, the support arm portion 52b effectively suppresses the movement of oil. The function as a baffle plate can be enhanced.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, the upper surface of the upper first member 53 of the oil strainer 51 is integrally formed with a rib 53e that protrudes upward toward the lower surface of the lower housing 21 of the balancer housing 19. The extending direction of the rib 53e is substantially orthogonal to the extending direction of the support arm portion 52b of the lower member 52.

  Thus, by integrally forming the ribs 53e on the upper first member 53, it is possible not only to increase the rigidity of the oil strainer 51, but also to allow the ribs 53e to function as a baffle plate so that the oil pan The oil level in the oil 13 can be more effectively suppressed. In particular, since the extending direction of the support arm portion 52b and the extending direction of the rib 53e are orthogonal to each other, the undulation of the liquid level can be suppressed regardless of the oil moving direction.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the oil return passage 58 and the oil discharge pipe portion 52d for returning the oil separated from the blow-by gas to the oil pan 13 are formed integrally with the oil strainer 51, but these are separated from the oil strainer 51. It may be formed on the body.

  In the embodiment, the lower member 52, the upper first member 53, and the upper second member 54 are made of synthetic resin mold products, but metal mold products (press products and die cast products). Can be configured.

The front view of the engine which concerns on the 1st Embodiment of this invention 2-2 sectional view of FIG. 3-3 arrow view of FIG. 4-4 arrow view of FIG. Sectional view along line 5-5 in FIG. 6-6 sectional view of FIG. Exploded perspective view of oil strainer viewed from diagonally below Exploded perspective view of oil strainer viewed from diagonally above Perspective view of balancer device with oil strainer The figure corresponding to the said FIG. 8 based on the 2nd Embodiment of this invention.

Explanation of symbols

13 Oil pan 19 Balancer housing 20a Oil return passage 52 Lower member 52e Oil outlet hole 54 Upper second member (upper member)
54b Oil inlet hole E Engine

Claims (1)

An engine oil return structure in which an oil return member for returning oil separated from blow-by gas to the oil pan (13) is disposed between the balancer housing (19) and the oil pan (13) of the engine (E),
The oil return member includes an upper member (54) made of a molded product in which an oil inlet hole (54b) connected to the oil return passage (20a) of the balancer housing (19) is formed, and oil in the oil pan (13). An oil return structure for an engine comprising a lower member (52) made of a molded product in which an oil outlet hole (52e) is formed.

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