Balancer device for engine

Abstract

To solve a problem that conventionally, a balancer shaft capable of suppressing stagnation of circulation of lubricating oil to be supplied to an engine block by using a small number of components has been required.SOLUTION: A balancer device 10 for an engine includes a pair of balancer shafts 11 provided below an engine block. A balancer device 10 includes a lower cover 23 coveting the pair of balancer shafts 11 from the lower side. The lower cover 23 includes an oil groove 26. The lower cover 23 includes a dropping hole 27 formed on the oil groove 26 and opened toward an oil pan. The lower cover 23 includes an inclined upper surface 25 inclined downwards toward the oil groove 26.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an engine balancer device that suppresses vibrations generated in the main motion system of an engine. [Background technology]

[0002] An engine has an engine block that houses the main moving system, such as pistons and a crankshaft. The engine has a balancer device to cancel out vibrations generated by the movement of the pistons and the movement of the crankshaft. The balancer device has a balancer shaft that rotates about its axis in conjunction with the rotation of the crankshaft, and balancer weights attached to the balancer shaft. The balancer shaft and balancer weights are housed in a balancer housing. As the balancer device is heavy, it is usually placed below the main moving system of the engine block.

[0003] Lubricating oil is constantly supplied to the main motion system. The lubricating oil falls into an oil pan located below the engine block. The lubricating oil that falls into the oil pan is filtered by an oil strainer, then pumped upward by an oil pump and supplied again to the main motion system.

[0004] The balancer device is disposed between the engine block and the oil pan in the vertical direction. If the lubricating oil that falls from the main motion system accumulates in the balancer device, the circulation of the lubricating oil supplied to the main motion system will be impeded. This may result in problems such as piston seizure.

[0005] Patent Document 1 describes a balancer device in which the balancer housing is composed of an upper housing and a lower housing, and a baffle plate is integrally provided at the upper end of the upper housing. The baffle plate is provided with a through hole for dropping the lubricating oil. The lower housing is provided with a jig insertion hole. The lubricating oil that drops onto the upper surface of the baffle plate flows toward the through hole of the baffle plate. The lubricating oil passes through the through hole of the baffle plate and the jig insertion hole of the lower housing and drops into the oil pan below. This makes it possible to prevent the lubricating oil from stagnating on the upper surface of the upper housing.

[0006] In order to provide a baffle plate, the number of parts in the balancer device increases. This increases the cost of parts and assembly. In addition, it is desirable to provide the balancer shaft close to the crankshaft in order to reduce the size and cost of the engine and to improve the power transmission from the crankshaft through the gears. Therefore, it is difficult to secure space to provide a baffle plate, etc., on the upper part of the balancer housing. In addition, the lubricating oil that falls from the through hole of the baffle plate may hit the balancer shaft or the balancer weight. When the lubricating oil hits the rotating balancer shaft or the balancer weight, it is stirred and foams. When the lubricating oil containing bubbles is filtered through an oil strainer, the flow rate of the passing oil decreases. This may cause the circulation of the lubricating oil to be stagnated. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2008-115917 A Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, there has been a demand for a balancer shaft that can suppress stagnation of the circulation of lubricating oil supplied to the engine block using a small number of parts. [Means for solving the problem]

[0009] According to one feature of the present disclosure, an engine balancer device has a pair of balancer shafts provided below an engine block. The engine balancer device has a lower cover covering the pair of balancer shafts from below. The lower cover has an oil groove. The lower cover has a drop hole formed in the oil groove and opening toward the oil pan. The lower cover has an inclined upper surface that slopes downward toward the oil groove.

[0010] Therefore, the lubricating oil that falls from the engine block to the lower cover flows from the inclined upper surface of the lower cover toward the oil groove below. The lubricating oil is further guided by the oil groove and falls from the drop hole to the oil pan below. This prevents the lubricating oil from stagnating in the engine balancer device. This prevents the circulation of the lubricating oil supplied to the engine block from stagnating. Furthermore, by forming the inclined upper surface, the oil groove, and the drop hole in the lower cover, it is possible to prevent an increase in the number of parts. This allows the manufacturing cost to be reduced. Moreover, the lower part of the engine balancer device is provided with a structure for guiding the lubricating oil, such as the inclined upper surface, the oil groove, and the drop hole. This allows the number of parts interposed between the upper end of the engine balancer device and the engine block in the vertical direction to be reduced. This allows the balancer shaft to be brought closer to the engine block, and improves the power transmission to the balancer shaft.

[0011] According to another feature of the present disclosure, the oil groove is inclined downward in the extension direction. A drop hole is provided at the lower end of the oil groove. This allows the lubricating oil to be smoothly sent from the oil groove to the drop hole below. Furthermore, the lubricating oil can be prevented from accumulating in the oil groove. This further prevents the circulation of the lubricating oil supplied to the engine block from stagnating.

[0012] According to another feature of the present disclosure, the lower cover has a top. The top is provided above an oil strainer that filters the lubricating oil accumulated in the oil pan. The inclined upper surface is inclined downward from the top toward the oil groove. Therefore, the drop hole and the oil groove are provided downstream of the inclined upper surface spaced apart from the top. Therefore, the position directly below the drop hole can be spaced apart from the oil strainer located below the top. Therefore, the lubricating oil that falls from the drop hole falls onto the upper surface of the oil pan spaced apart from the oil strainer. This makes it possible to prevent lubricating oil that has foamed as it falls from being taken into the oil strainer. This makes it possible to prevent a decrease in the flow rate of oil passing through the oil strainer.

[0013] According to another feature of the present disclosure, the lower cover has a top. The lower cover has a first inclined upper surface that is an inclined upper surface that is inclined downward in a first direction from the top. The lower cover has a second inclined upper surface that is an inclined upper surface that is inclined downward in a second direction opposite to the first direction. A first oil groove that is an oil groove extends along a lower edge of the first inclined upper surface. A second oil groove that is an oil groove extends along a lower edge of the second inclined upper surface.

[0014] Therefore, the lubricating oil that falls from the engine block to the lower cover flows from the first inclined upper surface toward the first oil groove. Alternatively, the lubricating oil flows from the second inclined upper surface toward the second oil groove. The lubricating oil that flows into the first oil groove flows toward the drop hole and falls into the oil pan. The lubricating oil that flows into the second oil groove flows toward the drop hole and falls into the oil pan. Therefore, the lubricating oil can be dropped into the oil pan at a position away from the area directly below the apex. For example, by arranging the oil strainer in the area directly below the apex, it is possible to prevent the lubricating oil that has foamed as it falls from being taken into the oil strainer. This makes it possible to prevent a decrease in the flow rate of oil passing through the oil strainer. [Brief description of the drawings]

[0015] [Figure 1] 1 is a vertical cross-sectional view that shows a schematic view of an engine according to an embodiment of the present invention. [Diagram 2]FIG. 1 is a perspective view showing an engine. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the present disclosure will be described in detail below with reference to FIGS. 1 to 5. The same reference numbers in the description refer to the same elements having the same functions, although duplicated description will not be given. FIG. 1 is a vertical cross-sectional view that shows an engine 1 according to this embodiment. FIG. 2 is a perspective view that shows an engine 1 according to this embodiment. FIG. 3 is a top view of a balancer device 10 according to this embodiment. FIG. 4 is a top view of a lower cover (lower surface) 23 of a balancer housing 20 according to this embodiment. FIG. 5 is a side view of the lower cover 23. Note that in FIGS. 4 and 5, the description of parts of the balancer housing 20 other than the lower cover 23 is omitted.

[0017] As shown in FIG. 1, an engine block 2 of an engine 1 is provided with a main motion system 3 that houses pistons, a crankshaft, etc. An oil pump 4 is provided in the engine block 2. Lubricating oil is constantly supplied to the main motion system 3 via the oil pump 4. An oil pan 5 is attached to the lower part of the engine block 2. A balancer device 10 for the engine is provided between the main motion system 3 and the oil pan 5 in the vertical direction. The balancer device 10 cancels and suppresses vibrations generated by the operation of the pistons, crankshaft, etc. of the main motion system 3. The balancer device 10 is provided close to the main motion system 3 in order to reduce the size and cost of the engine 1 and to improve power transmission by gears from the crankshaft.

[0018] As shown in FIG. 2, the balancer device 10 has a rectangular box-shaped balancer housing 20. The balancer housing 20 is formed by connecting an upper housing 21 and a lower housing 22 vertically. The upper housing 21 and the lower housing 22 are formed by molding, for example, an aluminum alloy material. The upper housing 21 and the lower housing 22 are fastened together and fixed to the lower surface of the engine block 2 by a plurality of bolts. The balancer housing 20 is divided into three rooms in the horizontal direction, for example. The upper and lower ends of each room of the upper housing 21 are opened in a rectangular shape. Lubricating oil that has dropped from the engine block 2 above can enter the balancer housing 20 from the upper end opening 21a of the upper housing 21.

[0019] 2 and 3, the upper end of the lower housing 22 is open so as to be able to communicate with the lower end of the upper housing 21. A plate-shaped lower cover 23 extending substantially horizontally is provided at the bottom of the lower housing 22 so as to form the bottom surface of the lower housing 22. The lower cover 23 covers each chamber of the balancer housing 20 and a pair of balancer shafts 11 (described below) from below. By providing the lower cover 23, the box-shaped shape of the balancer housing 20 can be maintained even when the upper end opening 21a of the upper housing 21 is open. Therefore, the rigidity of the entire balancer housing 20 can be maintained.

[0020] As shown in Figures 2 and 3, the balancer device 10 has a pair of balancer shafts 11 extending horizontally. The pair of balancer shafts 11 extend parallel to each other. A balancer weight 12 and a gear 13 are attached to each balancer shaft 11. The balancer shaft 11 equipped with the heavy balancer weight 12 rotates around its axis. This makes it possible to cancel vibrations generated by the movement of the pistons and crankshaft of the engine block 2. The balancer shaft 11 and the balancer weight 12 are exposed upward through an upper end opening 21a of the upper housing 21.

[0021] As shown in Fig. 3, the balancer shaft 11 is a drive-side shaft 11a to which a drive-side gear 13a is attached as a gear 13. The other balancer shaft 11 is a driven-side shaft 11b to which a driven-side gear 13b is attached as a gear 13. The drive-side gear 13a and the driven-side gear 13b mesh with each other. The drive-side shaft 11a receives rotational power from a crankshaft via a power transmission mechanism such as a chain and sprocket, a belt and pulley, or a gear train (not shown). The driven-side shaft 11b rotates by receiving the rotational power of the drive-side shaft 11a transmitted via the drive-side gear 13a and the driven-side gear 13b.

[0022] 2 and 3, the balancer device 10 has a plurality of bearings 14 that support each balancer shaft 11 rotatably about its axis. The plurality of bearings 14 are housed in wall portions that separate each chamber of the balancer housing 20. The plurality of bearings 14 are sandwiched and held between an upper housing 21 and a lower housing 22.

[0023] As shown in FIGS. 3 to 5, the lower cover 23 of the lower housing 22 has a top 24 at the center of the top surface. The top 24 is located at the highest position on the top surface of the lower cover 23. The top 24 is provided in a ridge shape extending linearly along the extension direction of the balancer shaft 11. The top 24 is located between the pair of balancer shafts 11. The lower cover 23 has a substantially flat inclined upper surface 25 that inclines downward from the top 24. The inclined upper surface 25 includes a first inclined upper surface 25a extending from the top 24 in a first direction in which the driving side shaft 11a is disposed, and a second inclined upper surface 25b extending from the top 24 in a second direction in which the driven side shaft 11b is disposed. In other words, the top surface of the lower cover 23 is formed in a mountain shape composed of the top 24 and the two inclined upper surfaces 25.

[0024] 3 to 5, an oil groove 26 extending linearly is formed on the upper surface of lower cover 23. Oil groove 26 extends along the downstream end of inclined upper surface 25. Oil groove 26 includes first oil groove 26a provided at the downstream end of first inclined upper surface 25a and second oil groove 26b provided at the downstream end of second inclined upper surface 25b. First oil groove 26a and second oil groove 26b extend approximately parallel to top portion 24.

[0025] 3 to 5, first oil groove 26a has circular drop holes 27 at both ends in the longitudinal direction, the drop holes 27 penetrating lower cover 23 and opening therethrough. The bottom surface of first oil groove 26a is formed in a mountain shape with two inclined surfaces sloping downward toward either of two drop holes 27, with the center in the longitudinal direction at the apex. Second oil groove 26b has circular drop holes 27 at both ends in the longitudinal direction, the drop holes 27 penetrating lower cover 23 and opening therethrough. The bottom surface of second oil groove 26b is formed in a mountain shape with two inclined surfaces sloping downward toward either of two drop holes 27, with the center in the longitudinal direction at the apex.

[0026] As shown in Figures 1 and 2, the oil pan 5 is provided with an oil strainer 6 that filters the lubricating oil. The lubricating oil filtered by the oil strainer 6 is pumped up by the oil pump 4 of the engine block 2 and supplied again to the main motion system 3. The oil strainer 6 has an oil intake 6a. The oil strainer 6 and the oil intake 6a are disposed below the balancer device 10 so as to be located approximately in the center of the balancer device 10 in the direction in which the pair of balancer shafts 11 are aligned. The oil intake 6a is disposed below the balancer device 10 so as to be located approximately in the center of the balancer device 10 in the direction in which the pair of balancer shafts 11 extend.

[0027] The flow of lubricating oil in the balancer device 10 will be described with reference to Figures 2 to 5. First, the lubricating oil dropping from the engine block 2 above enters the balancer housing 20 from the upper end opening 21a of the upper housing 21. Most of the lubricating oil drops onto the first inclined upper surface 25a or the second inclined upper surface 25b of the lower cover 23. Some of the lubricating oil hits the balancer shaft 11 or the balancer weight 12, but finally drops onto the first inclined upper surface 25a or the second inclined upper surface 25b of the lower cover 23. Therefore, even if the lubricating oil hits the balancer shaft 11 or the balancer weight 12 and bubbles, the air bubbles can be eliminated because of the distance to the drop hole 27.

[0028] The lubricating oil that has fallen onto the first inclined upper surface 25a flows downward toward the first oil groove 26a. The lubricating oil further flows toward one of the two drop holes 27 located at the lower end of the first oil groove 26a. The lubricating oil that has fallen onto the second inclined upper surface 25b flows downward toward the second oil groove 26b. The lubricating oil further flows toward one of the two drop holes 27 located at the lower end of the second oil groove 26b. The lubricating oil that has reached each drop hole 27 of the first oil groove 26a or the second oil groove 26b falls toward the oil pan 5. The lubricating oil falls to a drop position P directly below each drop hole 27 on the upper surface of the oil pan 5. The drop position P is a position separated from the oil strainer 6 and the oil inlet 6a. The lubricating oil that has fallen to the drop position P and accumulated in the oil pan 5 is filtered by the oil strainer 6, for example, via the oil inlet 6a.

[0029] As described above, the engine balancer device 10 has a pair of balancer shafts 11 provided below the engine block 2 as shown in Figures 2 and 3. The balancer device 10 has a lower cover 23 that covers the pair of balancer shafts 11 from below. The lower cover 23 has an oil groove 26. The lower cover 23 has a drop hole 27 that is formed in the oil groove 26 and opens toward the oil pan 5. The lower cover 23 has an inclined upper surface 25 that slopes downward toward the oil groove 26.

[0030] Therefore, the lubricating oil that has fallen from the engine block 2 to the lower cover 23 flows downward from the inclined upper surface 25 of the lower cover 23 toward the oil groove 26. The lubricating oil is further guided by the oil groove 26 and falls from the drop hole 27 to the oil pan 5 below. This prevents the lubricating oil from stagnating in the balancer device 10. This prevents the circulation of the lubricating oil supplied to the engine block 2 from stagnating. Furthermore, by forming the inclined upper surface 25, the oil groove 26, and the drop hole 27 on the lower cover 23, it is possible to prevent an increase in the number of parts. This allows the manufacturing cost to be reduced. Moreover, the lower part of the balancer device 10 is provided with a structure for guiding the lubricating oil, such as the inclined upper surface 25, the oil groove 26, and the drop hole 27. This allows the number of parts interposed between the upper end of the balancer device 10 and the engine block 2 in the vertical direction to be reduced. This allows the balancer shaft 11 to be brought closer to the engine block 2, and the power transmission to the balancer shaft 11 to be improved.

[0031] 3 to 5, the oil groove 26 is inclined downward in the extension direction. A drop hole 27 is provided at the lower end of the oil groove 26. This allows the lubricating oil to be smoothly sent from the oil groove 26 to the drop hole 27 below. Furthermore, the lubricating oil can be prevented from accumulating in the oil groove 26. This further prevents the circulation of the lubricating oil supplied to the engine block 2 from stagnating.

[0032] As shown in FIG. 3, the lower cover 23 has a top 24. The top 24 is provided above the oil strainer 6 that filters the lubricating oil accumulated in the oil pan 5. The inclined upper surface 25 is inclined downward from the top 24 toward the oil groove 26. Therefore, the drop hole 27 and the oil groove 26 are provided downstream of the inclined upper surface 25 separated from the top 24. Therefore, the position directly below the drop hole 27 can be separated from the oil strainer 6 and the oil intake port 6a located below the top 24. Therefore, the lubricating oil that falls from the drop hole 27 falls on the upper surface of the oil pan 5 separated from the oil strainer 6 and the oil intake port 6a. This makes it possible to prevent the lubricating oil that has foamed due to the fall from being taken into the oil strainer 6. This makes it possible to prevent a decrease in the flow rate of the oil passing through the oil strainer 6.

[0033] As shown in FIG. 3, the lower cover 23 has a top 24. The lower cover 23 has a first inclined upper surface 25a, which is an inclined upper surface 25 that is inclined downward in a first direction from the top 24. Lower cover 23 has second inclined upper surface 25b, which is an inclined upper surface 25 that inclines downward from top 24 in a second direction opposite to the first direction. First oil groove 26a, which is an oil groove 26, extends along the lower edge of first inclined upper surface 25a. Second oil groove 26b, which is an oil groove 26, extends along the lower edge of second inclined upper surface 25b.

[0034] Therefore, the lubricating oil that has fallen from the engine block 2 to the lower cover 23 flows from the first inclined upper surface 25a toward the first oil groove 26a. Alternatively, the lubricating oil flows from the second inclined upper surface 25b toward the second oil groove 26b. The lubricating oil that has flowed into the first oil groove 26a flows toward the drop hole 27 and falls into the oil pan 5. The lubricating oil that has flowed into the second oil groove 26b flows toward the drop hole 27 and falls into the oil pan 5. Therefore, the lubricating oil can be dropped into the oil pan 5 at a position separated from the area directly below the top 24. For example, by arranging the oil strainer 6 in the area directly below the top 24, it is possible to prevent the lubricating oil that has foamed due to the fall from being taken into the oil strainer 6. This makes it possible to prevent a decrease in the flow rate of the oil passing through the oil strainer 6.

[0035] Various modifications can be made to the engine 1 of the present embodiment described above. The balancer device 10 of the present disclosure may be applied to engines of various mechanisms, such as diesel engines and gasoline engines. The power transmission mechanism from the main motion system 3 to the balancer shaft may be appropriately selected from a chain and sprocket, a belt and pulleys, a gear train, or the like.

[0036] Although the balancer housing 20 is shown divided into three compartments, the present invention is not limited to this and may be, for example, a single box type without compartments, divided into two compartments, or divided into four or more compartments. A power transmission mechanism from the main motion system 3 may be disposed in any of the compartments of the balancer housing 20.

[0037] In the illustrated embodiment, the top 24 and oil groove 26 of the lower cover 23 are provided along the extending direction of the pair of balancer shafts 11. Alternatively, for example, the top 24 and oil groove 26 of the lower cover 23 may extend in a direction substantially perpendicular to the pair of balancer shafts 11. In this case, the first inclined upper surface 25a and the second inclined upper surface 25b are inclined from the top 24 downward toward the oil groove 26 in a direction substantially perpendicular to the pair of balancer shafts 11.

[0038] The inclined upper surface 25 and the bottom surface of the oil groove 26 are not limited to being flat or extending linearly. The inclined upper surface 25 and the bottom surface of the oil groove 26 may be curved without a depression for storing lubricating oil, or may extend in a curved line.

[0039] In the illustrated embodiment, a drop hole 27 is provided at each of both ends of the oil groove 26 in the longitudinal direction. Alternatively, for example, one drop hole 27 may be provided in the center of the oil groove 26 in the longitudinal direction. In this case, the bottom surface of the oil groove 26 slopes downward from both ends of the oil groove 26 in the longitudinal direction toward the central drop hole 27. In the illustrated embodiment, the drop hole 27 opens in a circular shape. The shape of the drop hole 27 is not limited to this, and may be, for example, elliptical, oval, polygonal, or the like. The drop hole 27 is not limited to having the same diameter from the inlet at the upper end to the outlet at the lower end, and may be formed in a tapered shape, for example, with the diameter decreasing downward.

[0040] The method of forming the top 24, the inclined upper surface 25, the oil groove 26, and the drop hole 27 on the lower cover 23 may be appropriately selected. For example, they may be formed by cutting the lower cover 23, which has a relatively large plate thickness, with a mill or the like. For example, they may be formed by deforming the lower cover 23, which has a relatively small plate thickness. [Explanation of symbols]

[0041] 1. Engine 2. Engine block 3…Main motor system 4. Oil pump 5. Oil pan 6...Oil strainer, 6a...Oil intake 10...Balancer device (engine balancer device) 11...balancer shaft, 11a...driving shaft, 11b...driven shaft 12. Balance weights 13... gear, 13a... driving gear, 13b... driven gear 14...Bearing 20…Balancer housing 21...upper housing, 21a...upper end opening 22…Lower housing 23…Lower cover 24…Top 25...Slanted top surface, 25a...First sloped top surface, 25b...Second sloped top surface 26...oil groove, 26a...first oil groove, 26b...second oil groove 27...Hole P…drop position

Claims

1. An engine balancer device, comprising: A pair of balancer shafts provided below the engine block; A lower cover is provided to cover the pair of balancer shafts from below, and the lower cover is Oil grooves and a drop hole formed in the oil groove and opening toward an oil pan; An engine balancer device having an inclined upper surface that slopes downward toward the oil groove.

2. 2. The engine balancer device according to claim 1, The oil groove is inclined downward in the extending direction, The engine balancer device has the drop hole provided at a lower end of the oil groove.

3. 3. The engine balancer device according to claim 1, The lower cover has a top portion, The top portion is provided above an oil strainer that filters the lubricating oil accumulated in the oil pan, The inclined upper surface slopes downward from the apex toward the oil groove.

4. 3. The engine balancer device according to claim 1, the lower cover has a top, a first inclined upper surface that is inclined downward from the top in a first direction, and a second inclined upper surface that is inclined downward from the top in a second direction opposite to the first direction, a first oil groove extends along a lower edge of the first inclined upper surface, A balancer device for an engine, wherein a second oil groove, which is the oil groove, extends along a lower edge of the second inclined upper surface.

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