JP2016094969A - Internal combustion engine balancer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate tolerance management of a thrust bearing for an input shaft in a balancer device having the input shaft.SOLUTION: This invention relates to a balancer device 10 comprising an input shaft 13 connected to a crank shaft 2 through a winding type first transmission mechanism 16; a rear balancer shaft 12R connected to the input shaft 13 through the second transmission mechanism 17; a front balancer shaft 12F connected to the rear balancer shaft 12R through the third transmission mechanism 18; an upper housing 14A and a lower housing 14B formed with a half-split bearing; and the input shaft 13 having a flange 13e which expands in diameter between the two journals 13c, 13d. A thrust bearing groove 14Bd forming a pair of thrust bearings 14e is formed at a position corresponding to a flange part of the lower housing 14B and a receiving groove 14Ad for receiving the flange under non-contacted state is formed at a position of the upper housing 14A corresponding to the flange part.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a balancer device that cancels secondary vibrations of an internal combustion engine.

  In reciprocating engines (hereinafter simply referred to as engines) mounted in automobiles, etc., two balancer shafts each having a balancer weight (counter weight) are arranged to cancel the secondary vibration generated by the piston, thereby transmitting power. A balancer device is installed to drive one balancer shaft by rotation of the crankshaft transmitted through the mechanism and to drive the other balancer shaft connected to each other by gears at the same speed in the opposite direction. May be.

  As such a balancer device, a first sprocket attached to a crankshaft and a second sprocket around which a first chain is wound are fixed to a first shaft, and a third gear fixed to the first shaft is used as a first balancer shaft. The fourth gear fixed to the first balancer shaft, the fifth gear fixed to the first balancer shaft and the sixth gear fixed to the second balancer shaft, and the same number of teeth of the first and second sprockets. The shaft is rotated at the same speed as the crankshaft, the number of teeth of the third gear is set to twice the number of teeth of the fourth gear, and the first balancer shaft is rotated at twice the number of rotations of the crankshaft. In addition, by setting the number of teeth of the sixth gear and the sixth gear to be the same, the first and second balancer shafts are rotated in the opposite direction at the same number of rotations. Is known structure in which a first axis downwards in Jin vertical direction (see Patent Document 1).

Japanese Patent No. 3707140

  Although not specified in Patent Document 1, in FIG. 1, the second sprocket and the seventh gear fixed to the first shaft are arranged so as to contact the journal bearing that supports the first shaft. It is presumed that the opposing surfaces of the second sprocket and the seventh gear become thrust bearings. However, when both side surfaces of the journal bearing are thrust bearing surfaces in this way, the journal bearing requires a predetermined width (length in the axial direction), and thus the distance between the pair of thrust bearing surfaces increases. Tolerance management becomes difficult.

  In the configuration of Patent Document 1, it is conceivable that both axial end surfaces of the seventh gear are thrust surfaces, and a thrust bearing surface is formed on the housing opposite to the thrust surfaces, but the gears also have a predetermined width (axial length). Moreover, since the seventh gear is sandwiched between the balancer housing and the pump cover, it is difficult to manage the tolerance of the distance between the pair of thrust bearing surfaces.

  Furthermore, since the balancer device usually forms a journal bearing by assembling a pair of upper and lower housings, the assembly accuracy of the upper and lower housings is also required, and if the tolerance of the distance between the thrust bearing surfaces is increased, the axial backlash is increased. There is a possibility that the sticking will be large and it may be difficult to assemble.

  In view of such a background, an object of the present invention is to facilitate tolerance management of a thrust bearing of a shaft in a balancer device having a shaft in addition to a pair of balancer shafts.

  In order to solve such problems, the present invention is provided in the internal combustion engine (1) and rotates a pair of balancer shafts (12F, 12R) in opposite directions at a rotational speed twice that of the crankshaft (2). A balancer device (10) to be connected to an input shaft (13) connected to the crankshaft via a winding-type first transmission mechanism (16) and at least a pair of gears (13f, 12Re, 51a) meshing with each other , 51b, 12Fe) and a pair of gears (12Rd, 12Fd) having the same number of teeth meshing with the first balancer shaft (12R, 12F) connected to the input shaft via the second transmission mechanism (17). A second balancer shaft (12F, 12R) connected to the first balancer shaft via a third transmission mechanism (18) comprising: A pair of upper and lower housings (14A and 14B) each formed with a half bearing for supporting the input shaft, the first balancer shaft, and the second balancer shaft, the input shaft comprising at least two It has a journal (13c, 13d) and a flange (13e) whose diameter is enlarged between the two journals, and is located at a position corresponding to the flange of one (14B) of the pair of upper and lower housings. A thrust bearing groove (14Bd) is formed to form a pair of thrust bearing surfaces (14e) for supporting a thrust load of the input shaft transmitted from both surfaces of the portion, and the flanges of the other pair (14A) of the upper and lower housings A receiving groove (1) having a width wider than the flange and receiving the flange in a non-contact state at a position corresponding to the flange. A structure in which Ad) is formed.

  According to this configuration, since the pair of thrust bearing surfaces of the thrust bearing of the input shaft is formed by the thrust bearing groove corresponding to the width of the flange portion, the distance between the thrust bearing surfaces can be reduced. Further, since the thrust bearing surface of the input shaft is constituted by the thrust bearing surface formed on one of the upper and lower housings, assembly accuracy is not required to form the thrust bearing. Therefore, it is possible to easily manage the tolerance of the distance between the thrust bearing surfaces.

  In the above invention, the thrust bearing groove (14Bd) is formed in the lower housing (14B), and the receiving groove (14Ad) is formed in the upper housing (14A). The thrust bearing surface (14e) may have an oil supply groove (14f) that extends in the radial direction of the input shaft and supplies lubricating oil.

  According to this configuration, since the lubricating oil is likely to be accumulated in the lower housing due to gravity, the lubricating oil is easily supplied to the thrust bearing groove. Also, the lubricating oil is easily supplied to the thrust bearing surface by forming the oil supply groove. Further, an upward tensile force is applied to the input shaft from the winding-type first transmission mechanism, and stress is generated between the two journals so that the input shaft is bent downward. Since the collar portion is supported by the thrust bearing groove of the lower housing, the support rigidity of the input shaft is increased, and the deflection of the input shaft is suppressed.

  Further, in the above invention, the oil supply grooves formed on the pair of thrust bearing surfaces communicate with each other through a peripheral portion of the flange portion in the thrust bearing groove, and the input shaft is one of the two journals. A gear (13f) formed integrally to form the second transmission mechanism (17) between (13d) and the flange (13e), and the other of the two journals (13c) and the flange The bottom surface (14g) of the lower housing (14B) between the lower portion and the gear portion may be lower than the bottom surface (14h) of the lower housing between the flange portion and the gear.

  According to this configuration, the oil is scraped by the gear on the gear side with respect to the collar portion, so that the oil tends to be insufficient. Sufficient lubricating oil can be supplied to both thrust bearing surfaces from the oil collecting groove.

  As described above, according to the present invention, in a mechanical device having a plurality of rotating shafts, the size of the device can be reduced, the number of processing and assembly processes can be reduced, and the required amount of lubricating oil and friction can be reduced.

Sectional drawing which shows the engine lower part which concerns on embodiment along a balancer shaft Sectional view along the line II-II in FIG. Enlarged view of part III in Fig. 1 Enlarged view showing the IV input shaft in Fig. 2 in perspective Enlarged view of part V in FIG. Sectional view along line VI-VI in FIG. Explanatory drawing which shows the power transmission path | route of the balancer apparatus shown in FIG. Schematic diagram of a balancer device according to a modified embodiment

  Hereinafter, an embodiment in which a balancer device 10 according to the present invention is applied to an in-line four-cylinder automobile engine (hereinafter simply referred to as an engine 1) will be described in detail with reference to the drawings.

  As shown in FIG. 1, the engine 1 is an in-line four-cylinder engine in which a crankshaft 2 extends in a horizontal direction, and is mounted on an automobile in a posture in which a cylinder axis is inclined rearward. The vertical direction is determined in a state where the engine 1 is mounted on the automobile. However, in the following description, in order to facilitate explanation and understanding, the cylinder axis direction extending substantially vertically and the crankshaft direction perpendicular thereto Are assumed to be up, down, left and right, and directions are indicated by arrows in FIG.

  The engine 1 forms a cylinder and has an upper block 3 having a skirt portion at the lower portion, and a lower block 5 coupled to the lower portion of the upper block 3 and defining a crank chamber 4 in cooperation with the skirt portion of the upper block 3. An oil pan 6 that is coupled to the lower part of the lower block 5 and defines an oil reservoir below the crank chamber 4; a balancer device 10 that is coupled to the lower part of the lower block 5 and disposed inside the oil pan 6; ing. Hereinafter, the upper block 3 and the lower block 5 are collectively referred to as a cylinder block 7.

  The crankshaft 2 has four crankpins 2a (hereinafter referred to as first to fourth crankpins 2a in order from the left side) that are connected via a connecting rod 8 and a piston pin of a piston (not shown) that is slidably provided in the cylinder. ), Five journals 2b (hereinafter referred to as the first to fifth journals 2b in order from the left side) provided at positions sandwiching the crankpin 2a, a crank arm 2c for connecting the journal 2b and the crankpin 2a, and a crank arm 2c is provided with a counterweight 2d integrally formed on the side opposite to the crankpin 2a. The first and fourth crankpins 2a are disposed at the same phase position, and the second and third crankpins 2a are disposed at the same phase position that is 180 degrees out of phase with the first and fourth crankpins 2a. .

  The bearing wall that pivotally supports the first and fifth journals 2b of the crankshaft 2 is constituted by the left wall and the right wall of the cylinder block 7, and the bearing wall that pivotally supports the second to fourth journals 2b is located in the crank chamber 4. It is comprised by the provided partition.

  The left end of the crankshaft 2 extends further leftward from the first journal 2 b and protrudes from the left wall of the cylinder block 7. The protruding portion includes a relatively large-diameter large sprocket 2e (drive sprocket) for driving the balancer device 10 and a relatively small-diameter small sprocket 2f for driving a camshaft (not shown) on the first journal 2b side. It is fixed in this order. A chain case 9 is provided outside the small sprocket 2 f so as to penetrate the crankshaft 2. A crank pulley 2g for driving an auxiliary machine of the engine 1 is fixed to the left end of the crankshaft 2 located outside the chain case 9.

  The balancer device 10 reduces the secondary vibration of the engine 1 caused by the reciprocating motion of the piston. As shown in FIG. 2, the balancer device 10 includes a pair of front and rear balancer shafts 12 (a front balancer shaft 12F and a rear balancer shaft 12R) arranged in parallel with the crankshaft 2, and coaxially with the front balancer shaft 12F. And a balancer housing 14 that supports and accommodates the two balancer shafts 12F and 12R and the input shaft 13. Both balancer shafts 12F and 12R are disposed at the same height in the cylinder axial direction.

  The balancer housing 14 is composed mainly of an upper housing 14A and a lower housing 14B which are divided into two vertically along a plane passing through the axis (rotation center) of the balancer shafts 12F and 12R. The upper housing 14A and the lower housing 14B are shaped to form an opening in the right side wall when assembled together. This opening is closed by a housing plate 14C provided with a seal member on the periphery. The bottom wall of the lower housing 14B is formed with a pin insertion hole 14a (FIG. 1) for inserting a pin (not shown) so as to fix the input shaft 13 so that the shafts 12 and 13 do not rotate during assembly. .

  The balancer housing 14 has a liquid-tight structure in which oil cannot enter from other than the pin insertion hole 14a and an oil discharge port described later in order to suppress an increase in friction due to oil agitation. The balancer device 10 has a lower surface (a crankshaft) of the lower block 5 by a through bolt (not shown) inserted from below into bolt insertion holes 14b (five places shown in FIG. 2 in this embodiment) provided at appropriate positions of the balancer housing 14. 2 below).

  The balancer housing 14 is formed with six journal bearings 21 to 26 constituted by half bearings formed in the upper housing 14A and the lower housing 14B, respectively. The first to fourth journal bearings 21 to 24 are arranged in order from the left on the axis (axis and extension thereof) of the front balancer shaft 12F, and the fifth and sixth journal bearings 25 and 26 are arranged on the rear balancer shaft 12R. Arranged in order from the left on the axis. In the present specification, the phrase “arranged on the axis (or axis)” for the bearing means that the bearing is arranged around the axis (or axis) coaxially with the axis (or axis). is there.

  The fifth journal bearing 25 and the sixth journal bearing 26 are disposed behind them at the same position in the left-right direction as the third journal bearing 23 and the fourth journal bearing 24, respectively. The bearing walls forming the third journal bearing 23 and the fifth journal bearing 25 and the bearing walls forming the fourth journal bearing 24 and the sixth journal bearing 26 are each configured as an integral wall continuous in the front-rear direction. The The widths of the third to sixth journal bearings 23 to 26 are larger than the widths of the first and second journal bearings 21 and 22 and have substantially the same dimensions.

  The upper housing 14A and the lower housing 14B are fastened to each other by a plurality of bolts B (see FIG. 6) inserted into a plurality of bolt holes 14c arranged at appropriate positions. In the present embodiment, two bolt holes 14c are provided on the wall connecting the bearing wall forming the first journal bearing 21 and the bearing wall forming the second journal bearing 22, and the third and fifth journal bearings 23, 25. And three formed on the bearing walls forming the fourth and sixth journal bearings 24 and 26, and eight in total. The bolt hole 14c is disposed outside (front and rear) of the first and second journal bearings 21 and 22 in the connecting wall, and two journal bearings 23, 25, 24, and 26 are provided in the two bearing walls, respectively. And the outside of the two journal bearings 23, 25, 24, 26. As shown in FIG. 6, the bolt hole 14c is configured as an insertion hole penetrating the upper housing 14A in the upper housing 14A, and is configured as a female screw hole into which the bolt B is screwed in the lower housing 14B. Is inserted into the bolt hole 14c from above. A female screw hole to which an oil passage described later is connected has a bottom.

  1 and 2, the input shaft 13 is provided so as to protrude leftward from the balancer housing 14, and a driven sprocket 13a is fixed at a position corresponding to the large sprocket 2e in the crankshaft direction of the protruding portion. Has been. Further, the input shaft 13 is formed with a first journal 13b and a second journal 13c on the right side of the driven sprocket 13a with a relatively small interval, and with a relatively large interval on the right side from the second journal 13c. A third journal 13d is formed at the right end. The first, second, and third journals 13b, 13c, 13d of the input shaft 13 are supported by first, second, and third journal bearings 21, 22, 23, respectively.

  A roller chain 15 is wound around the large sprocket 2 e of the crankshaft 2 and the driven sprocket 13 a of the input shaft 13. That is, the large sprocket 2e, the roller chain 15, and the driven sprocket 13a constitute a winding-type first transmission mechanism 16 that transmits the rotational force of the crankshaft 2 to the input shaft 13. The input shaft 13 rotates in the same direction as the crankshaft 2.

  On the right side of the second journal 13c of the input shaft 13, a bowl-shaped thrust plate 13e (collar) that expands in diameter is integrally formed, and on the right side of the thrust plate 13e (between the thrust plate 13e and the third journal 13d). The first helical gear 13f having a relatively large diameter is fixed. Both surfaces of the thrust plate 13e (both end surfaces in the axial direction of the input shaft 13) serve as thrust surfaces that transmit the thrust load of the input shaft 13 to the balancer housing 14, as will be described later.

  In order to form a thrust bearing at a position corresponding to the thrust plate 13e of the balancer housing 14 for receiving at least the peripheral edge portion of the thrust plate 13e and supporting at least a part of the thrust load transmitted from both surfaces of the thrust plate 13e. The groove 14d (14Ad, 14Bd) is formed in an annular shape.

  As shown in FIG. 3 which is an enlarged view of part III in FIG. 1, the groove 14d has a width wider than the thrust plate 13e in the upper housing 14A, and accepts the thrust plate 13e in a non-contact state. The groove 14Ad is formed in a semicircular arc shape. On the other hand, in the lower housing 14B, the groove 14d has substantially the same width as the thrust plate 13e, and supports a thrust load of the input shaft 13 through a thin fluid film in surface contact with both surfaces of the thrust plate 13e. The thrust bearing grooves 14Bd forming the thrust bearing surfaces 14e and 14e are formed in a semicircular arc shape. That is, the wall portion of the lower housing 14B in which the thrust bearing groove 14Bd is formed constitutes the thrust bearing of the input shaft 13.

  FIG. 4 is an enlarged perspective view showing a portion IV in FIG. 2 with the input shaft 13 removed. As shown in FIGS. 3 and 4, the thrust bearing surfaces 14e and 14e of the lower housing 14B are provided with oil supply grooves 14f extending in the radial direction of the input shaft 13 and supplying lubricating oil to the thrust bearing surfaces 14e and 14e. , 14f are formed. In the present embodiment, one oil supply groove 14f extending in the vertical direction is formed at the center in the front-rear direction of each thrust bearing surface 14e. Both the oil supply grooves 14f, 14f extend below the lower end of the thrust plate 13e, and communicate with each other through a gap formed around the thrust plate 13e in the thrust bearing groove 14Bd.

  As shown in FIG. 3, the bottom surface 14g of the lower housing 14B between the second journal 13c of the input shaft 13 and the thrust plate 13e is the lower housing 14B between the first helical gear 13f of the input shaft 13 and the thrust plate 13e. It is lower than the bottom surface 14h.

  As shown in FIG. 5 showing an enlarged view of the V portion of FIG. 1, a bottomed hole 13 g having a circular cross section is formed on the shaft end surface (right end surface) of the input shaft 13 on the front balancer shaft 12 </ b> F side. Formed on top. That is, the end of the input shaft 13 on the front balancer shaft 12F side (at least a part of the third journal 13d) is formed by a cylindrical wall having a uniform thickness. The bottomed hole 13g is formed by drilling, and its bottom surface 13h has a conical shape in accordance with the shape of the tip of the drill. Further, the side peripheral surface of the bottomed hole 13g (substantially coincides with the inner peripheral surface of the third journal 13d) is finished smoothly so that it can be used as a journal bearing surface. The depth d (axial length) of the side peripheral surface of the bottomed hole 13g is slightly larger than the width (axial length) of the third journal 13d of the input shaft 13.

  As shown in FIG. 2, both balancer shafts 12F and 12R are formed in positions corresponding to the third and fifth journal bearings 23 and 25, respectively, in the first journals 12Fa (see FIG. 5), 12Ra, And second journals 12Fb and 12Rb formed at positions corresponding to the sixth journal bearings 24 and 26. Further, the balancer shafts 12F and 12R are provided on the left and right sides of the second journals 12Fb and 12Rb, respectively, and a pair of left and right balancer weights 12Fc of substantially the same shape with its center of gravity biased radially outward from the center of rotation. 12Fc, 12Rc, 12Rc and first helical gears 12Fd, 12Rd fixed between the left balancer weights 12Fc, 12Rc and the first journals 12Fa, 12Ra.

  In the rear balancer shaft 12R, the first journal 12Ra is pivotally supported by the fifth journal bearing 25, and the second journal 12Rb is pivotally supported by the sixth journal bearing 26. On the other hand, as shown in FIG. 5, the front balancer shaft 12F is disposed so that the first journal 12Fa disposed at the left end enters the bottomed hole 13g of the input shaft 13, and the second journal 12Fb is disposed in the fourth journal. It is supported by a journal bearing 24.

  That is, the first journal 12Fa of the front balancer shaft 12F is pivotally supported by the third journal 13d of the input shaft 13, which is a portion that defines the bottomed hole 13g. The first journal 12Fa of the front balancer shaft 12F has an axial length that is slightly smaller than the depth d of the side peripheral surface of the bottomed hole 13g, and is disposed at substantially the same position as the third journal bearing 23 in the left-right direction. The Accordingly, the third journal 13d of the input shaft 13 directly supports the first journal 12Ra of the front balancer shaft 12F, but the third journal bearing 23 is substantially the third journal 13d of the input shaft 13. The first journal 12Fa of the front balancer shaft 12F is pivotally supported.

  A bearing metal 28 is disposed on the fourth journal bearing 24 and the sixth journal bearing 26 that pivotally support the second journals 12Fb, 12Rb between the left and right balancer weights 12Fc, 12Rc.

  In both the balancer shafts 12F and 12R, the portions of the pair of left and right balancer weights 12Fc and 12Rc facing each other have a bowl shape whose diameter is larger than that of the second journals 12Fb and 12Rb (see FIGS. 1 and 2). The opposed inner surfaces of the bowl-shaped portions are thrust surfaces that transmit a thrust force to the fourth journal bearing 24 or the sixth journal bearing 26. That is, the bearing walls forming the fourth and sixth journal bearings 24 and 26 also serve as thrust bearings that support the axial loads of the balancer shafts 12F and 12R.

  As shown in FIG. 2, in the front balancer shaft 12F, the first journal 12Fa forms the left end as described above. On the other hand, the rear balancer shaft 12R extends further leftward from the first journal 12Ra, and a second helical gear 12Re that meshes with the first helical gear 13f of the input shaft 13 is fixed to the extended portion. That is, the first transmission gear 17 that transmits the rotational force of the input shaft 13 to the rear balancer shaft 12R is configured by the first helical gear 13f and the second helical gear 12Re. As a result, the rear balancer shaft 12R rotates in the direction opposite to the input shaft 13. Note that the directions of twisting of the second helical gear 12Re and the first helical gear 12Rd of the rear balancer shaft 12R are the same, thereby reducing the axial load of the rear balancer shaft 12R.

  The first helical gear 12Rd of the rear balancer shaft 12R and the first helical gear 12Fd of the front balancer shaft 12F are engaged with each other, and the rotational force of the rear balancer shaft 12R is applied to the front balancer shaft 12F by the first helical gears 12Rd and 12Fd. A third transmission mechanism 18 for transmission is configured. The first helical gears 12Rd and 12Fd constituting the third transmission mechanism 18 have the same diameter and the same number of teeth (speed-up gear ratio = 1), and both balancer shafts 12F and 12R are the same in opposite directions. It rotates at the rotation speed.

  The speed increasing ratio of the first transmission mechanism 16 and the second transmission mechanism 17 is set so that both the balancer shafts 12F and 12R have a rotational speed twice that of the crankshaft 2. Specifically, in the present embodiment, the chain transmission speed ratio of the first transmission mechanism 16 is set to 4/3, the speed increase gear ratio of the second transmission mechanism 17 is set to 3/2, and the first transmission mechanism The speed increasing ratio of the mechanism that combines 16 and the second transmission mechanism 17 is 2.

  Therefore, when the rotational speed of the crankshaft 2 is 1, the rotational speed of the input shaft 13 is 4/3 (the same direction as the crankshaft 2), and the rotational speed of the front balancer shaft 12F is 2 (the same direction as the crankshaft 2). Thus, the relative rotational speed of the front balancer shaft 12F with respect to the input shaft 13 (that is, the rotational speed of the first journal 12Fa of the front balancer shaft 12F with respect to the third journal 13d of the input shaft 13 which is a bearing) is 2/3.

  The diameter and the number of teeth (the number of teeth) of the driven sprocket 13a are 3/4 times the diameter and the number of the large sprocket 2e (FIG. 1), and the rotational speed of the input shaft 13 is twice the rotational speed of the crankshaft 2. It becomes larger than the ratio (1/2 times). Thereby, the noise in the 1st transmission mechanism 16 becomes small.

  On the other hand, the diameter and the number of teeth of the first helical gear 13f of the input shaft 13 are 3/2 times the diameter and the number of teeth of the second helical gear 12Re of the rear balancer shaft 12R, and the rotational speed of the input shaft 13 is the rotation of the crankshaft 2. It becomes larger than the ratio (1 time) when the speed is doubled. As a result, as will be described later, in the present embodiment in which only the first helical gear 13f of the input shaft 13 is submerged to lubricate the second transmission mechanism 17, friction due to oil agitation is reduced.

  Engine oil that is sucked from an inlet of an oil strainer in the oil pan 6 by an oil pump (not shown) and pumped toward each part of the engine 1 is supplied to each sliding portion of the balancer device 10 through an oil passage. Used as a lubricating oil. Specifically, in the balancer device 10, engine oil is supplied to the first to sixth journal bearings 21 to 26.

  Hereinafter, the configuration of the oil passage in the balancer device 10 will be described. As shown in FIG. 1, an in-block oil passage 29 that supplies oil from the main gallery to the balancer device 10 is provided on a bearing wall that supports the first journal 2 b of the crankshaft 2. The oil supplied from the oil passage 29 in the block is introduced into the balancer device 10 from the upper surface of the upper housing 14A, and supplied to the joint surface with the lower housing 14B through an oil passage (not shown) extending vertically.

  As shown in FIG. 2, oil passage grooves 30 (30A, 30B) are formed on the upper surface of the lower housing 14B. Although detailed illustration is omitted, an oil passage groove 30 is similarly formed on the lower surface of the upper housing 14A. In the oil passage groove 30, the left end portion of the front end of the lower housing 14B serves as an oil inlet 30a. The oil passage groove 30 branches into a first branch groove 30A extending rearward from the oil inlet 30a and a second branch groove 30B extending rightward.

  The first branch groove 30A is curved after extending backward from the oil inlet 30a, extends to the left to reach the connection wall, and is formed in an annular shape along the periphery of the bolt hole 14c (around the bolt B) in the connection wall. Has been. The first branch groove 30A is formed in an arc shape in the upper halves of the bearing surfaces of the first and second journal bearings 21 and 22 as shown in FIG. 3 from the annular portion through the lower surface of the upper housing 14A. The oil is supplied to the bearing gap between the first and second journal bearings 21 and 22 and the first and second journals 13b and 13c of the input shaft 13.

  As shown in FIG. 2, the second branch groove 30B extends rightward from the oil inlet 30a, curves and extends rearward at the front end portions of the bearing walls forming the third and fifth journal bearings 23 and 25, and is bolted. After extending along the periphery of the hole 14c, it reaches the front end of the third journal bearing 23. As shown in FIG. 6, in the third journal bearing 23, the second branch groove 30 </ b> B is formed in an annular shape along the bearing surface at the center in the width direction of the third journal bearing 23. Oil is supplied to a bearing gap between the third journal 13d of the input shaft 13 and the input shaft 13.

  The second branch groove 30B extends rearward from the rear end of the third journal bearing 23 again, extends along the periphery of the bolt hole 14c, and then reaches the front end of the fifth journal bearing 25. Also in the fifth journal bearing 25, the second branch groove 30B is formed in an annular shape along the bearing surface at the center in the width direction of the fifth journal bearing 25, and the fifth journal bearing 25 and the rear balancer shaft 12R Oil is supplied to the bearing gap between one journal 12Ra.

  As shown in FIGS. 5 and 6, at the center of the input journal 13 in the width direction (axial direction) of the third journal 13 d, there is at least one oil supply hole 31 that penetrates the cylindrical wall and communicates inside and outside. Is formed. In this embodiment, the two oil supply holes 31 are linearly formed at positions different by 180 °. Each oil supply hole 31 opens in the outer peripheral surface of the third journal 13d and the side peripheral surface of the bottomed hole 13g (inner peripheral surface of the third journal 13d).

  The front balancer shaft 12F has a bottomed shaft oil passage 32F extending in the axial direction from the left end surface and reaching at least the center in the width direction of the second journal 12Fb (see FIG. 1). The opening at the left end of the in-shaft oil passage 32F is closed by a plug 33 (check ball). The rear balancer shaft 12R is also formed with an in-shaft oil passage 32R (FIG. 6) that is similarly closed by the plug 33.

  An annular groove 34 is formed on the outer peripheral surface at the center in the width direction of the first journal 12Fa of the front balancer shaft 12F, and the annular groove 34 and the shaft oil passage 32F are communicated in the radial direction so as to communicate with each other. At least one oil introduction hole 35F extending is formed. In this embodiment, the two oil introduction holes 35F are linearly formed at positions different by 180 °. As shown in FIGS. 1 and 2, at the center of the front balancer shaft 12F in the width direction of the second journal 12Fb, there is at least one oil outlet hole 36F communicating the inner shaft inner oil passage 32F with the outer. Is formed. In the present embodiment, one oil lead-out hole 36F is formed on the side opposite to the balancer weight 12Fc (the side where the bearing gap is large).

  On the other hand, as shown in FIGS. 2 and 6, at the center in the width direction of the first journal 12Ra of the rear balancer shaft 12R, it extends at least in the radial direction so as to communicate the inner shaft inner oil passage 32R with the outer side. One oil introduction hole 35R is formed. In the present embodiment, the two oil introduction holes 35R are linearly formed at positions different by 180 °. In addition, as shown in FIG. 2, at least one oil outlet hole 36R is formed in the center of the rear balancer shaft 12R in the width direction of the second journal 12Rb so as to communicate the inner shaft inner oil passage 32R with the outer side. Has been. Similar to the front balancer shaft 12F, in the present embodiment, one oil lead-out hole 36R is formed on the side opposite to the balancer weight 12Rc (side where the bearing clearance is large).

  In the oil passage structure configured as described above, as shown in FIGS. 5 and 6, the oil flowing through the annular portion of the second branch groove 30 </ b> B formed in the third journal bearing 23 is the oil of the input shaft 13. The oil is supplied to the inner bearing surface of the third journal 13d through the supply hole 31 (the bearing gap between the front balancer shaft 12F and the first journal 12Fa) and from the oil introduction hole 35F through the annular groove 34. It flows into the oil passage 32F in the shaft of the front balancer shaft 12F. The oil that has flowed into the oil passage 32F in the shaft is supplied to the bearing gap between the second journal 12Fb and the fourth journal bearing 24 (bearing metal 28) through the oil outlet hole 36F as shown in FIGS. Is done.

  Similarly, as shown in FIGS. 2 and 6, the oil flowing through the annular portion of the second branch groove 30 </ b> B formed in the fifth journal bearing 25 passes through the oil introduction hole 35 </ b> R and the oil in the shaft of the rear balancer shaft 12 </ b> R. It flows into the path 32R. The oil that has flowed into the oil passage 32R in the shaft is supplied to the bearing gap between the second journal 12Rb and the sixth journal bearing 26 (bearing metal 28) through the oil outlet hole 36R as shown in FIG.

  The above is the configuration of the oil supply path for the journal bearings 21 to 26. Next, the structure of the oil discharge path used for lubricating the journal bearings 21 to 26 and the oil supply path to the thrust bearing will be described.

  As shown in FIG. 3, the oil supplied to the first journal bearing 21 and the second journal bearing 22 by the first branch groove 30A leaks to the left and right, respectively. The oil leaking to the left from the first journal bearing 21 is collected in the oil pan 6 as it is. The oil leaking to the right from the first journal bearing 21 enters the balancer housing 14 from a pin insertion hole 14a formed in the bottom wall between the first journal bearing 21 and the second journal bearing 22 of the lower housing 14B. It is discharged and collected in the oil pan 6. Similarly, oil leaking to the left from the second journal bearing 22 is also discharged out of the balancer housing 14 through the pin insertion hole 14 a and is collected in the oil pan 6.

  The pin insertion hole 14a is formed in the bottom wall of the lower housing 14B, and the oil in the oil pan 6 can enter the balancer device 10 from the pin insertion hole 14a, but the pin insertion hole 14a is formed in the first journal. Since it is formed between the bearing 21 and the second journal bearing 22, the increase in friction due to the ingress of oil is extremely small.

  On the other hand, oil leaking to the right from the second journal bearing 22 is supplied to a thrust bearing groove 14Bd formed in the lower housing 14B, and between the pair of thrust bearing surfaces 14e, 14e and both surfaces of the thrust plate 13e. Used for lubrication of thrust bearings. At this time, the oil is supplied from the oil supply groove 14f to the thrust bearing surface 14e. Further, as described above, since the pair of oil supply grooves 14f and 14f communicate with each other, the oil supply groove 14f also functions as a discharge oil passage. That is, the oil accumulated on the left side of the thrust plate 13e can flow to the right side of the thrust plate 13e through both the oil supply grooves 14f and 14f. On the other hand, since the bottom surface 14g of the lower housing 14B on the left side of the thrust plate 13e is lower than the bottom surface 14h on the right side of the thrust plate 13e as described above, there is no oil in the left oil supply groove 14f. The lack of lubricating oil for the thrust bearing is prevented.

  Further, as described above, the receiving groove 14Ad of the upper housing 14A receives the thrust plate 13e in a non-contact state, and the clearance between the receiving groove 14Ad and the thrust plate 13e is also the oil collected on the left side of the thrust plate 13e. It functions as a drain oil passage leading to the right side of the plate 13e. The gap of the receiving groove 14Ad not only guides the oil to the right side of the thrust plate 13e when the oil on the left side of the thrust plate 13e accumulates above the axis of the input shaft 13, but also places the left side of the thrust plate 13e. Even when the oil has accumulated only to a level below the axial center of the input shaft 13, the oil scattered by the centrifugal force of the thrust plate 13e and attached to the ceiling surface or the like can be guided to the right side of the thrust plate 13e. it can.

  The oil that has moved to the right of the thrust plate 13e in this manner accumulates in a recess that receives the first helical gear 13f of the input shaft 13 and the second helical gear 12Re of the rear balancer shaft 12R, as shown in FIGS. This is used for lubrication of the first helical gear 13f and the second helical gear 12Re (second transmission mechanism 17). At this time, since the diameter of the first helical gear 13f of the input shaft 13 is larger than the diameter of the second helical gear 12Re of the rear balancer shaft 12R, the oil accumulates in a recess that receives the first helical gear 13f and adheres to the first helical gear 13f. Used for lubrication. The oil scraped up and scattered by the first helical gear 13f is discharged out of the balancer device 10 through an oil discharge port (not shown) formed in the upper wall of the upper housing 14A and is collected in the oil pan 6.

  Further, oil that is provided for lubrication between the third journal bearing 23 and the third journal 13d of the input shaft 13 and leaks to the left from the third journal bearing 23 is also provided for lubrication of the second transmission mechanism 17 and input. It is scraped up by the first helical gear 13 f of the shaft 13 and discharged out of the balancer device 10. The same applies to the oil that is used for lubrication with the rear balancer shaft 12R in the fifth journal bearing 25 and leaks to the left from the fifth journal bearing 25.

  2 and 5, between the third journal 13d of the input shaft 13 and the first helical gear 13f, that is, closer to the bottom of the bottomed hole 13g than the first journal 12Fa at the left end of the front balancer shaft 12F. In addition, at least one oil discharge hole 37 penetrating in a radial direction through a part defining the bottomed hole 13g is formed. Since the bottom surface 13h of the bottomed hole 13g has a conical shape as described above, the radially inner end of the oil discharge hole 37 opens to the bottom surface 13h of the bottomed hole 13g. In this embodiment, the two oil discharge holes 37 are linearly formed at positions different by 180 °.

  Therefore, the oil that is lubricated in the bearing gap between the third journal 13d of the input shaft 13 and the first journal 12Fa of the front balancer shaft 12F and leaks to the left is the oil discharge hole from the bottom of the bottomed hole 13g. In the same manner as described above, the second transmission mechanism 17 is lubricated, and the second transmission mechanism 17 is scraped up by the first helical gear 13f of the input shaft 13 and discharged out of the balancer device 10.

  As shown in FIGS. 1 and 2, the oil leaking to the right from the third journal bearing 23, the bottomed hole 13g of the third journal 13d of the input shaft 13 and the fifth journal bearing 25 is the balancer shafts 12F, 12R. The first helical gears 12Fd and 12Rd are accumulated in the recesses to receive the first helical gears 12Fd and 12Rd (the third transmission mechanism 18). The oil scraped up and scattered by the first helical gears 12Fd and 12Rd is discharged out of the balancer device 10 through an oil discharge port (not shown) formed in the upper wall of the upper housing 14A and is collected in the oil pan 6.

  In the fourth journal bearing 24 and the sixth journal bearing 26, the oil supplied to the bearing gap (inside the bearing metal 28) and lubricated leaks left and right from the bearing gap, and then the side and right and left sides of the bearing wall. The thrust bearings 12Fc and 12Rc are used for lubricating the thrust bearing. Thereafter, the oil accumulates in a recess for receiving the pair of left and right balancer weights 12Fc, 12Rc, and in the recess for receiving the first helical gears 12Fd, 12Rd constituting the third transmission mechanism 18 through the communication path 38 indicated by a broken line in FIG. It is swept up by the first helical gears 12Fd and 12Rd and discharged out of the balancer device 10.

  The communication path 38 is formed at a position lower than the lower ends of the balancer weights 12Fc and 12Rc in a state where the pair of left and right balancer weights 12Fc and 12Rc are at the lowest position (the state shown in FIG. 1). When the engine 1 is not tilted in the left-right direction, the lower ends of the first helical gears 12Fd, 12Rd of the third transmission mechanism 18 are lower than the lower ends of the balancer weights 12Fc, 12Rc (from the maximum radius of the balancer weights 12Fc, 12Rc). Also, the maximum radius of the first helical gears 12Fd and 12Rd is larger). Further, as described above, the balancer housing 14 has a structure in which oil cannot enter from other than the oil discharge port formed in the pin insertion hole 14a and the upper wall of the upper housing 14A. Therefore, in the state where the inertial force in the left-right direction does not act and the oil level is horizontal, the oil level is lower than the lower ends of the balancer weights 12Fc, 12Rc by scooping up the oil by the first helical gears 12Fd, 12Rd. This prevents an increase in friction due to oil agitation of the balancer weights 12Fc and 12Rc.

  In the balancer device 10 configured as described above, power is transmitted as indicated by arrows in FIG. 7 while each sliding portion and the meshing portion are lubricated with oil. That is, the rotational force of the crankshaft 2 is transmitted to the input shaft 13 via the large sprocket 2e (FIG. 1), the roller chain 15 (FIG. 1) and the driven sprocket 13a of the first transmission mechanism 16, and the second transmission mechanism 17 Is transmitted to the rear balancer shaft 12R via the first helical gear 13f and the second helical gear 12Re. As described above, the rear balancer shaft 12R rotates in the opposite direction to the crankshaft 2 at a rotational speed twice that of the crankshaft 2. The rotational force of the rear balancer shaft 12R is transmitted to the front balancer shaft 12F via the two first helical gears 12Rd and 12Fd constituting the third transmission mechanism 18. The pair of front and rear balancer shafts 12F and 12R rotate at the same rotational speed in opposite directions. As a result, an inertial force in the cylinder axis direction that cancels the secondary vibration of the engine 1 is generated.

  As described above, as shown in FIG. 2, the balancer device 10 includes at least a pair of first helical gears 13 f that mesh with the input shaft 13 connected to the crankshaft 2 via the winding-type first transmission mechanism 16. And a third transmission mechanism 18 comprising a pair of first helical gears 12Rd and 12Fd having the same number of teeth meshing with the rear balancer shaft 12R connected to the input shaft 13 via the second transmission mechanism 17 including the second helical gear 12Re. A pair of upper housings 14A and a lower housing each formed with a front balancer shaft 12F connected to the rear balancer shaft 12R via the input shaft 13, and half bearings for supporting the input shaft 13, the rear balancer shaft 12R and the front balancer shaft 12F. And a housing 14B. The input shaft 13 includes at least two second and third journals 13c and 13d, and a thrust plate 13e that expands the diameter of the second and third journals 13c and 13d. Further, as shown in FIG. 3, a pair of thrust bearing surfaces 14e and 14e for supporting the thrust load of the input shaft 13 transmitted from both surfaces of the thrust plate 13e are formed at positions corresponding to the thrust plate 13e of the lower housing 14B. A thrust bearing groove 14Bd is formed, and a receiving groove 14Ad having a width wider than the thrust plate 13e and receiving the thrust plate 13e in a non-contact state is formed at a position corresponding to the thrust plate 13e of the upper housing 14A. Yes.

  As a result, the pair of thrust bearing surfaces 14e, 14e forming the thrust bearing of the input shaft 13 is formed by the thrust bearing groove 14Bd corresponding to the width of the thrust plate 13e, so the distance between the thrust bearing surfaces is reduced. Further, since the thrust bearing surface 14e formed in the lower housing 14B constitutes the thrust bearing of the input shaft 13, assembly accuracy for forming the thrust bearing is not required. Therefore, it becomes easy to manage the tolerance of the distance between the thrust bearing surfaces.

  In the present embodiment, the thrust bearing groove 14Bd is formed in the lower housing 14B, the receiving groove 14Ad is formed in the upper housing 14A, and the oil supply groove 14f extending in the radial direction is formed in the thrust bearing surface 14e of the lower housing 14B. ing. Therefore, lubricating oil that tends to accumulate in the lower housing 14B due to gravity is easily supplied to the thrust bearing groove 14Bd. Further, the lubricating oil is easily supplied to the thrust bearing surface 14e by forming the oil supply groove 14f. Further, an upward tensile force is applied from the winding type first transmission mechanism 16 to the driven sprocket 13a of the input shaft 13, and the stress is such that the input shaft 13 is bent downward between the second and third journals 13c and 13d. However, since the thrust plate 13e provided between the second and third journals 13c and 13d is supported by the thrust bearing groove 14Bd of the lower housing 14B, the support rigidity of the input shaft 13 is increased, and the input shaft 13 Is suppressed.

  In this embodiment, the oil supply groove 14f formed in the pair of thrust bearing surfaces 14e and 14e communicates with each other via the peripheral portion of the thrust plate 13e in the thrust bearing groove 14Bd, and as shown in FIGS. The shaft 13 has a first helical gear 13f integrally formed to constitute the second transmission mechanism 17 between the third journal 13d and the thrust plate 13e, and the lower portion between the second journal 13c and the thrust plate 13e. The bottom surface 14g of the housing 14B is lower than the bottom surface 14h of the lower housing 14B between the thrust plate 13e and the first helical gear 13f. For this reason, the oil tends to be insufficient on the first helical gear 13f side with respect to the thrust plate 13e because the oil is scraped up by the first helical gear 13f, but the bottom surface 14g is lower on the second journal 13c side than the thrust plate 13e. Therefore, the lubricating oil is accumulated, and sufficient lubricating oil is supplied to both thrust bearing surfaces 14e and 14e from the oil supply groove 14f.

<< Modified Embodiment >>
Next, a balancer device 10 according to a modified embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the element which has the same form or function as the said embodiment, and the overlapping description is abbreviate | omitted.

  In the above-described embodiment, in the power transmission from the crankshaft 2 to the pair of balancer shafts 12F and 12R, the winding-type first transmission mechanism 16 and the gear-type second transmission mechanism 17 including a pair of gears meshing with each other are used. In contrast to the two-stage speed increase, in the balancer device 10 of the present modified embodiment, the second transmission mechanism 17 includes two speed-up mechanisms (two pairs of gears), and the three-stage speed increase. Done.

  This will be specifically described below. The balancer device 10 includes an intermediate shaft 51 arranged in parallel to the input shaft 13 in addition to the pair of front and rear balancer shafts 12F and 12R and the input shaft 13. In the present modified embodiment, the intermediate shaft 51 is disposed coaxially with the rear balancer shaft 12R. A first helical gear 51a that meshes with the first helical gear 13f of the input shaft 13 is fixed to the intermediate shaft 51, and a second helical gear 51b is fixed at a position spaced to the right from the first helical gear 51a.

  The configuration of the pair of balancer shafts 12F and 12R is also different from the above embodiment. Specifically, in the rear balancer shaft 12R, the first journal 12Ra is at the left end, and the second helical gear 12Re is not provided. In the front balancer shaft 12F, a second helical gear that meshes with the second helical gear 51b at a position between the first journal 12Fa and the first helical gear 12Fd and corresponding to the second helical gear 51b of the intermediate shaft 51 in the left-right direction. 12Fe is fixed.

  The intermediate shaft 51 includes a first journal 51c at the right end, a second journal 51d that is pivotally supported by a seventh journal bearing 27 between the first helical gear 51a and the second helical gear 51b, and has a circular cross section at the right end surface. A bottom hole 51g is formed. The second journal 51d may be provided on the left side of the first helical gear 51a as indicated by an imaginary line. The first journal 51c of the intermediate shaft 51 is pivotally supported by the fifth journal bearing 25, and the rear balancer shaft 12R is arranged so that the first journal 12Ra enters the bottomed hole 51g of the intermediate shaft 51. That is, the fifth journal bearing 25 substantially supports both the first journal 51c of the intermediate shaft 51 and the first journal 12Ra of the rear balancer shaft 12R. On the other hand, the third journal bearing 23 is substantially the same as the above embodiment in that both the third journal 13d of the input shaft 13 and the first journal 12Fa of the front balancer shaft 12F are pivotally supported.

  The first gear mechanism 17A is constituted by the first helical gear 13f of the input shaft 13 and the first helical gear 51a of the intermediate shaft 51, and the second gear mechanism is constituted by the second helical gear 51b of the intermediate shaft 51 and the second helical gear 12Fe of the front balancer shaft 12F. 17B is configured. The second transmission mechanism 17 is configured by the intermediate shaft 51, the first gear mechanism 17A, and the second gear mechanism 17B.

  In the balancer device 10 configured as described above, power is transmitted as indicated by arrows in the drawing. That is, the rotational force of the crankshaft 2 transmitted to the input shaft 13 via the first transmission mechanism 16 including the driven sprocket 13a is transmitted to the intermediate shaft 51 via the first gear mechanism 17A of the second transmission mechanism 17. The The rotational force of the intermediate shaft 51 is transmitted to the front balancer shaft 12F via the second gear mechanism 17B of the second transmission mechanism 17, and the front balancer shaft 12F is the same as the crankshaft 2 at a rotational speed twice that of the crankshaft 2. Rotate in the direction. The rotational force of the front balancer shaft 12F is transmitted to the rear balancer shaft 12R via the third transmission mechanism 18, and the rear balancer shaft 12R is rotated at the same rotational speed in a direction opposite to the front balancer shaft 12F.

  The chain speed increase ratio of the first transmission mechanism 16 is greater than 1 so that the rotational speed of the input shaft 13 is faster than the rotational speed of the crankshaft 2 and slower than the rotational speed of the front balancer shaft 12F. It is set to be smaller than 2. The speed increasing gear ratio of the first gear mechanism 17A of the second transmission mechanism 17 is such that the rotational speed of the intermediate shaft 51 is faster than the rotational speed of the input shaft 13 and slower than the rotational speed of the front balancer shaft 12F. It is set larger than 1 and smaller than 2. For example, when the chain speed increasing ratio of the first transmission mechanism 16 is set to 4/3, the speed increasing gear ratio of the first gear mechanism 17A is 4/3, and the speed increasing gear ratio of the second gear mechanism 17B is 9 /. By setting it to 8, the rotational speed of the balancer shafts 12F and 12R becomes twice the rotational speed of the crankshaft 2.

  Although illustration is omitted, the intermediate shaft 51 may be provided with a thrust member similar to the thrust plate 13e of the input shaft 13, and a thrust bearing may be provided in the lower housing 14B. The position of the thrust member provided on the intermediate shaft 51 may be between the first helical gear 51a and the second helical gear 51b or to the left of the first helical gear 51a.

  Although the detailed illustration of the oil passage structure is omitted, the oil passage having the configuration shown in FIG. 5 is applied to the fifth journal bearing 25, the intermediate shaft 51, and the rear balancer shaft 12R in the same manner as in the above embodiment. That's fine. Specifically, an oil supply hole 31 and an oil discharge hole 37 (FIG. 5) are formed in the intermediate shaft 51, and an annular groove 34 is formed in the rear balancer shaft 12R in addition to the oil introduction hole 35R (FIG. 6). To do.

  The balancer device 10 configured as described above can also achieve the same effects as those of the above embodiment.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above-described embodiment, the balancer device 10 for the in-vehicle internal combustion engine has been described as an example. Moreover, in the said embodiment, although the helical gear is used for the gear of the 2nd transmission mechanism 17 or the 3rd transmission mechanism 18, you may use a spur gear, a helical gear, etc. In the above embodiment, the roller chain 15 is used for the winding-type first transmission mechanism 16, but a chain having another structure such as a silent chain may be used. In the above embodiment, the annular groove 34 is formed on the outer peripheral surface of the first journal 12Fa of the front balancer shaft 12F, but the annular groove 34 is formed on the side peripheral surface of the bottomed hole 13g of the input shaft 13. Also good. In addition, the specific configuration, arrangement, quantity, angle, and the like of each member and part can be changed as appropriate without departing from the spirit of the present invention. On the other hand, all the elements of the balancer device 10 shown in the above embodiment are not necessarily essential, and can be selected as appropriate.

1 Engine 2 Crankshaft 2e Large sprocket (element of first transmission mechanism 16)
10 balancer device 12F front balancer shaft 12Fd first helical gear (element of third transmission mechanism 18)
12Fe second helical gear (element of second transmission mechanism 17)
12R Rear balancer shaft 12Rd First helical gear (element of third transmission mechanism 18)
12Re 2nd helical gear (element of 2nd transmission mechanism 17)
13 Input shaft 13a Driven sprocket (element of first transmission mechanism 16)
13c 2nd journal 13d 3rd journal 13e Thrust plate
13f 1st helical gear (element of 2nd transmission mechanism 17)
14 balancer housing 14A upper housing 14Ad receiving groove 14B lower housing 14Bd thrust bearing groove 14e thrust bearing surface 14f oil supply groove 14g bottom surface (between second journal 13c and thrust plate 13e)
14h Bottom surface (between first helical gear 13f and thrust plate 13e)
15 Roller chain (element of first transmission mechanism 16)
16 First transmission mechanism 17 Second transmission mechanism 18 Third transmission mechanism 51 Intermediate shaft (element of second transmission mechanism 17)
51a First helical gear (element of second transmission mechanism 17)
51b Second helical gear (element of second transmission mechanism 17)

Claims (3)

A balancer device provided in an internal combustion engine for rotating a pair of balancer shafts in opposite directions at a rotational speed twice that of a crankshaft,
An input shaft connected to the crankshaft via a winding-type first transmission mechanism;
A first balancer shaft connected to the input shaft via a second transmission mechanism including at least a pair of gears meshing with each other;
A second balancer shaft connected to the first balancer shaft via a third transmission mechanism comprising a pair of gears having the same number of teeth meshing with each other;
A pair of upper and lower housings each formed with a half bearing for supporting the input shaft, the first balancer shaft, and the second balancer shaft;
The input shaft has at least two journals and a flange that expands between the two journals;
A thrust bearing groove that forms a pair of thrust bearing surfaces that support the thrust load of the input shaft transmitted from both surfaces of the flange is formed at a position corresponding to one of the flanges of the pair of upper and lower housings. ,
In a position corresponding to the other flange portion of the pair of upper and lower housings, a receiving groove having a width wider than the flange portion and receiving the flange portion in a non-contact state is formed. The balancer device for an internal combustion engine according to claim 1. The thrust bearing groove is formed in the lower housing, and the receiving groove is formed in the upper housing;
2. The oil supply groove that extends in a radial direction of the input shaft and supplies lubricating oil is formed in the pair of thrust bearing surfaces formed in the lower housing. A balancer device for an internal combustion engine as described. The oil supply grooves formed on the pair of thrust bearing surfaces communicate with each other via a peripheral portion of the flange in the thrust bearing groove;
The input shaft has a gear integrally formed to constitute the second transmission mechanism between one of the two journals and the flange portion,
The bottom surface of the lower housing between the other of the two journals and the flange portion is lower than the bottom surface of the lower housing between the flange portion and the gear. 3. A balancer device for an internal combustion engine according to 2.

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