JP2010270595A - Balancer for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balancer for an internal combustion engine, reducing the rotational friction and inhibiting the occurrence of cavitation in an oil pump. <P>SOLUTION: This balancer includes a balancer housing 7 mounted on a cylinder block in a state inclined to the gravity direction in an oil pan 4 and rotatably holding a drive side and a driven side balancer shaft 8, 9 therein, an oil strainer 33 disposed at the gravity direction lowermost position biased to the driven balancer shaft side disposed on a gravity direction lower side of the balancer housing, and an oil pump disposed in the housing. In the balancer housing, an oil discharge hole 32 discharging the inside oil in the oil pan is formed on an upper wall on the drive side balancer shaft side and part around the driven side balancer shaft is blocked. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improvement of a balancer device that reduces secondary vibration of an internal combustion engine.

  As is well known, a balancer device for an internal combustion engine is attached to the lower part of the crankcase of the engine and accommodated in an oil pan, and is rotatably accommodated in the housing via a bearing, and rotates from the crankshaft. A driving-side balancer shaft to which a force is transmitted; and a driven-side balancer shaft to which a rotational force is transmitted from the driving-side balancer shaft.

  When the crankshaft is rotationally driven by the engine start, the drive-side balancer shaft is rotationally driven at a rotational speed twice that of the crankshaft via a gear or the like, and the driven side meshes with the drive-side gear as it rotates. The gear rotates in the reverse direction to drive the driven side balancer shaft in the direction opposite to the drive side balancer shaft. As a result, the secondary vibration of the engine is effectively suppressed by the rotation of each counterweight.

  In addition, when the driving of the internal combustion engine is stopped, the oil level in the oil pan rises, the oil flows into the housing, and the driving-side balancer shaft or the driven-side balancer shaft becomes oil. It will be immersed.

  Therefore, when the engine is started and the balancer shafts rotate, the counterweights rotate while stirring the oil in the housing, so that the rotational friction increases and a rotational driving load of the internal combustion engine is generated.

  Therefore, as described in Patent Document 1 below, oil discharge holes are provided on both the drive-side balancer shaft side and the driven-side balancer shaft side of the housing, and the oil in the housing is allowed to rotate during the rotation of each balancer shaft. There is provided a technique for reducing rotational friction by discharging into an oil pan.

JP 2006-118514 A

  By the way, in the balancer device, an oil pump is integrally provided in the housing, and when the oil pump is driven, the oil in the oil pan is passed through an oil strainer provided in the lower portion of the housing. Inhaled and supplied to the sliding part of the engine.

  However, in the balancer device described in the above publication, a large amount of air is mixed in the oil that is discharged from the oil discharge hole into the oil pan through the oil discharge hole as the balancer shafts rotate. For this reason, cavitation or the like is likely to occur in the oil pump due to the bubble mixed oil sucked through the oil strainer, and the discharge hydraulic pressure may be lowered.

  The present invention provides a balancer device for an internal combustion engine that improves the efficiency of oil discharge from the inside of the housing to reduce rotational friction and can suppress the mixing of bubbles into the oil sucked by the oil pump. .

  In the invention described in claim 1, in particular, an oil strainer provided on the lower surface of the gravity direction at a position biased toward one of the rotating bodies arranged on the lower side of the housing in the gravity direction; An oil pump that is provided in the housing and is rotationally driven by the drive rotating body or the driven rotating body and sucks oil in the oil pan from the oil strainer and supplies it to the sliding portion of the engine, The housing has an oil discharge hole for discharging oil in the housing into the oil pan at a position on the other rotating body side located on the upper side in the gravity direction, and on the lower side in the gravity direction. A feature is that the periphery of one of the positioned rotating bodies is closed.

  The oil in the housing that has been scooped up with the rotation of the drive rotating body or the like is efficiently discharged from the oil discharge holes that are uniquely arranged. For this reason, rotation friction can be reduced.

  Moreover, the oil strainer is provided on the lower surface in the gravity direction at a position biased toward one of the rotating bodies arranged on the lower side in the gravity direction of the housing. Even if air bubbles are mixed, the air bubbles can be prevented from wrapping in the oil strainer direction. Therefore, the suction of bubbles in the oil pump can be sufficiently suppressed.

It is sectional drawing along CC line of FIG. 6 which shows the balancer apparatus concerning the 1st Embodiment of this invention. It is a fragmentary sectional view showing the state where the balancer device was attached to the engine. It is a side view of the balancer device of this embodiment. It is sectional drawing along the AA line of FIG. It is sectional drawing along the BB line of FIG. It is a bottom view of the balancer device of this embodiment. It is sectional drawing along CC line of FIG. 6 which shows the balancer apparatus of 2nd Embodiment.

Hereinafter, an embodiment in which a balancer device according to the present invention is applied to, for example, an in-line four-cylinder internal combustion engine of an automobile will be described with reference to the drawings.
[First Embodiment]
As shown in FIG. 2, a ladder frame 3 made of an aluminum alloy material having a bearing portion that supports the crankshaft 2 is fixed to the lower portion of the cylinder block 1 of the internal combustion engine. In addition, an oil pan 4 storing internal engine oil O is attached. Further, the internal combustion engine is formed in an inclined shape with the left side lowered in FIG. 2 due to the layout in the engine room, and the inclined lower surface 4a of the oil pan 4 is disposed horizontally.

  The crankshaft 2 is rotatably supported by a plurality of bearings composed of bearing caps and the like that are coupled to the lower part of the cylinder block 1 by bearing bolts (not shown), and is large on a shaft 2a that is integrally provided on the front end side. A diameter crank sprocket 5 is attached.

  The crank sprocket 5 is formed in a ring shape and is coupled to the shaft portion 2a of the crankshaft 2 by shrink fitting through an insertion hole 5a formed in the center portion, and has a gear portion 5b on the outer periphery. ing.

  A balancer device 6 for suppressing secondary vibrations of the engine is accommodated in a space surrounded by the lower part of the cylinder block 1, the ladder frame 3 and the oil pan 4. As shown in FIG. 1, the balancer device 6 is disposed so as to be inclined at the same angle as the inclination angle of the internal combustion engine. It is arranged to be.

  As shown in FIGS. 1 to 6, the balancer device 6 includes a balancer housing 7 fixed to the lower surface of the oil pan 4, and is rotatably supported in the balancer housing 7 so as to extend in the longitudinal direction of the engine. A driving-side balancer shaft 8 that is a driving rotating body and a driven-side balancer shaft 9 that is a driven rotating body, which are arranged in parallel, and each tooth portion that is provided substantially at the center of each of the balancer shafts 8 and 9. Are provided with a helical drive side gear 10 and a driven side gear 11 which are meshed with each other, and an oil pump 12 provided at a front end portion of the balancer housing 7 on the driven side balancer shaft 9 side.

  The balancer housing 7 is formed of an aluminum alloy material as a whole, and includes a lower housing 13 on the oil pan 4 side and an upper housing 14 disposed on the upper portion of the lower housing 13. The plurality of bolts 15 are fastened and fixed from above and below.

  As shown in FIG. 4, the drive-side balancer shaft 8 is fixed to the front end portion of the tip shaft 8c by a fixing bolt 16 in which a balancer sprocket 17 is screwed from the axial direction. The balancer sprocket 17 and the crank The rotational force from the crankshaft 2 is transmitted via a drive chain 31 wound between the sprocket 5. As a result, the balancer shafts 8 and 9 are rotated in opposite directions via the driving gear 10 and the driven gear 11. The shafts 8 and 9 are set to rotate twice per rotation of the crankshaft 2.

  Further, as shown in FIG. 4, the drive side balancer shaft 8 has journal portions 8a and 8b formed on the front end side and the rear end side in the axial direction, and the journal portions 8a and 8b are connected to the lower housing 13. And two bearing portions 19a and 19b respectively provided at corresponding positions of the upper housing 14 are rotatably supported. A half-circular plain bearing 20 is interposed on the bearing 19b side on the rear side.

  In addition, lubricating oil is supplied from an oil passage, which will be described later, through semicircular oil grooves 19c and 19d formed on the inner peripheral surfaces of the bearing portions 19a and 19b of the housings 13 and 14, respectively.

  Two semi-circular counterweights 21a and 21b are integrally provided at the front and rear positions sandwiching the rear journal 8b of the drive side balancer shaft 8.

  The drive-side gear 10 is fixed to the drive-side balancer shaft 8 by press fitting or the like, and as shown in FIG. 4, the drive-side gear 10 is sandwiched by opposing thrust walls 13a and 13b of the lower housing 13 and moves in the axial direction. Being regulated.

  On the other hand, the driven-side balancer shaft 9 has an axial length shorter than that of the driving-side balancer shaft 8 as shown in FIG. 5, and journal portions 9a and 9b formed at two axial positions are provided on the both sides. It is rotatably supported via two bearing portions 22a and 22b provided between the housings 13 and 14. A half-circular plain bearing 23 is interposed on the rear bearing portion 22b side.

  Further, lubricating oil is supplied from an oil passage not shown through semicircular oil grooves 22c and 22d formed on the inner peripheral surfaces of the bearing portions 22a and 22b of the housings 13 and 14, respectively. .

  Two semi-circular counterweights 24a and 24b are integrally provided at the front-rear position of the driven-side balancer shaft 9 with the journal portion 9b on the rear side interposed therebetween.

  The driven gear 11 is fixed to the driven balancer shaft 9 by press-fitting or the like, and as shown in FIG. 5, the driven gear 11 is sandwiched between opposed thrust walls 13c and 13d of the lower housing 13 to move in the axial direction. Being regulated.

  The oil pump 12 is a general trochoid type, and as shown in FIGS. 5 and 6, a pump housing 26 coupled and fixed to the front end side of the balancer housing 7 by a plurality of bolts 25, and the pump housing 26 The inner rotor 27 and the outer rotor 28 are rotatably accommodated in the interior.

  The inner rotor 27 is rotatably driven by the driven balancer shaft 9 with the small-diameter tip portion 9c of the driven balancer shaft 9 passing through and fixed to a fixing hole 27a formed penetrating in the axial direction. Yes. As shown in FIG. 5, the inner rotor 27 has a cylindrical portion 27b protruding from the center and is fitted into a fitting hole 26a formed in the pump housing 26, so that the inner rotor 27 can rotate together with the small diameter tip portion 9c. Bearings.

  In addition, a suction port 30 communicating with an oil suction passage 29 formed in the lower portion of the lower housing 13 is formed in the pump housing 26, and pumping action accompanying the rotation of the rotors 27 and 28 is formed. A discharge port (not shown) for discharging the oil sucked from the suction port 30 is formed. The oil discharged from the discharge port is supplied to each sliding portion and driving portion of the engine through the discharge passage.

  Further, two oil discharge holes 32, 32 for discharging the oil O stored in the balancer housing 7 into the oil pan 4 are formed in the upper wall portion 14 a on the drive side balancer shaft 8 side of the upper housing 14. Has been.

  That is, as shown in FIGS. 1 and 3, the two oil discharge holes 32, 32 are formed in the two counterweights on the substantially flat upper wall portion 14a on the drive side balancer shaft 8 side, which is located on the upper side in the direction of gravity. The counterweights 21a and 21b are formed at positions corresponding to the outer circumferential edges of the counterweights 21a and 21b, and are formed substantially linearly along the tangential direction of the outer peripheral edge rotation direction. That is, the one end openings 32a and 32a facing the inside of the balancer housing 7 are formed along the upper wall portion 14a as an extension, and the other end openings 32b and 32b are rotated at the outer peripheral edges of the counterweights 21a and 21b. It is formed linearly in the tangential direction of the direction and faces the oil pan 4.

  The arcuate upper wall portion 14b on the driven-side balancer shaft 9 side of the upper housing 14, that is, the driven-side counterweights 24a, 24b side, is closed without being opened.

  As shown in FIG. 1, a part of the oil stored in the oil pan 4 is stored in the balancer housing 7 when the engine is stopped. Below L, the entire driven-side balancer shaft 9 including the counterweights 24a and 24b is disposed, and the entire driving-side balancer shaft 8 and a part of the counterweights 21a and 21b are disposed.

  Further, as shown in FIGS. 1, 5 and 6, the lower housing 13 filters oil O stored in the oil pan 4 when the oil pump 12 is driven to filter the oil in the oil suction passage 29. An oil strainer 33 is provided to flow into the tank.

  The oil strainer 33 includes a saucer-shaped metal retainer 34 and a mesh-shaped filter member 35 held by the retainer 34. The retainer 34 is formed with a flange portion 34a that is fixed by press-fitting or caulking into an annular holding groove on the inner peripheral surface of the cylindrical wall 13e integrally formed on the lower end portion of the lower housing 13 at the outer peripheral edge. A substantially semicircular opening 34b is formed in the bottom wall. The bottom wall is provided with five protrusions 34c for forming a predetermined gap with the inner bottom surface of the oil pan 4 on the outer peripheral side and the substantially central side.

  The arrangement of the oil strainer 33 is biased toward the driven balancer shaft 9 side of the lower housing 13, as shown in FIG. That is, it is disposed and fixed on the cylindrical wall 13e formed closer to the driven balancer shaft 9 than the center line X between the two balancer shafts 8 and 9, and is positioned at the lowest position in the gravity direction.

  Therefore, according to the balancer device 6, when the engine is started and the crankshaft 2 is rotationally driven, the drive-side balancer shaft 8 moves in one direction via the crank sprocket 5, the drive chain 31 and the balancer sprocket 17. Rotate at twice the speed. As a result, the driven-side balancer shaft 9 rotates at the same speed in the opposite direction to the driving-side balancer shaft 8 through the meshing rotation transmission between the driving-side gear 10 and the driven-side gear 11.

  Therefore, each counterweight 21a, 21b, 24a, 24b also cancels the centrifugal force of the balancer shaft itself while rotating in opposite directions.

  At this time, the balancer housing 7 prevents the oil O staying in the oil pan 4 and the balancer shafts 8 and 9 from interfering with each other, and receives a vibration force generated when the balancer shafts 8 and 9 rotate. At the same time, the vibration is transmitted to the engine.

  In addition, the inner rotor 27 and the outer rotor 28 rotate as the driven balancer shaft 9 rotates, and the oil pump 12 operates to pump the oil O in the oil pan 4 through the oil strainer 33. At the same time, it is discharged to each sliding part of the engine.

  As described above, when the counterweights 24a and 24a are rotated in accordance with the rotation of the driven-side balancer shaft 9 to scoop up the oil O in the balancer housing 7, the scooped up oil O 32 and 32 are efficiently discharged into the oil pan 4. That is, since the oil discharge holes 32, 32 are formed along the tangential direction of the outer peripheral edge rotation direction of the counterweights 24a, 24a, the oil O that has been scooped up is left as it is as the outer peripheral edges of the counterweights 24a, 24a Since the oil is scattered in the direction of the oil discharge holes 32 and 32 by centrifugal force, it can be efficiently discharged.

  For this reason, it is possible to sufficiently reduce the stirring resistance of the balancer shafts 8 and 9 by the oil O, that is, the rotational friction, and as a result, the rotational load of the engine can be reduced.

  Particularly, since the oil discharge holes 32 and 32 are opened in the direction in which the centrifugal force of the counterweights 24a and 24a acts, the oil O in the balancer housing 7 is swept up by the counterweights 24a and 24a and centrifuged. Since it is directly scattered in the direction, it is easy to be discharged into the oil pan 4 from the oil discharge holes 32 and 32.

  In addition, a part of the oil O that has been scraped up by the counterweights 24a and 24a and scattered in the direction of the oil discharge holes 32 and 32 hits the lower surface of the upper wall portion 14a and is directly guided into the oil pan 4. The oil O discharge is further improved.

  In addition, since the oil strainer 33 is provided at a position biased toward the driven balancer shaft 9 disposed on the lower side of the housing in the gravitational direction and at the lowest position in the gravitational direction, each counterweight Even if air bubbles are mixed in the oil in the oil pan 4 by the stirring action of 21a, 21b 24a, 24b, the air bubbles can be prevented from flowing in the direction of the oil strainer 33. Therefore, the bubbles in the oil O sucked into the oil pump 12 are greatly reduced, and the occurrence of cavitation and the decrease in the discharge hydraulic pressure can be suppressed.

Also,
[Second Embodiment]
FIG. 7 shows a second embodiment of the present invention. In this embodiment, the oil surface level L in the oil pan 4 is further increased, and the arrangement position of the oil strainer 33 is reduced while reducing the size of the oil strainer 33. It is biased further away from the direction.

  That is, first, the oil level L of the oil O in the oil pan 4 when the engine drive is stopped is set high so that almost the entire upper housing 14 of the balancer housing 7 is buried, and the driven balancer shaft 9 In addition, the counterweights 21a and 21b side of the drive side balancer shaft 8 are also set to such a height that most of them are immersed in the oil O.

  Further, the cylindrical wall 13e provided in the lower housing 13 is formed to have a small outer diameter, and a part thereof is positioned on the center line X between the balancer shafts 8 and 9.

  On the other hand, the outer diameter of the oil strainer 33 is also set small according to the outer diameter of the cylindrical wall 13e. Therefore, the oil strainer 33 is disposed at a position away from the center line X, that is, at a biased position further away from the oil discharge holes 32 and 32 diagonally.

  Therefore, since the height of the oil pan 4 can be made as small as possible, the vertical height of the entire internal combustion engine can be reduced, and the degree of freedom of layout in the engine room is improved.

  Further, since the journal portions 8a, 8b, 9a, 9b of the drive side balancer shaft 8 and the driven side balancer shaft 9 are also immersed in the oil, the journal portions 8a-9b and the bearing portions 19a, 19b, Lubricity between 22a and 22b is further improved.

The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.
(A) In the balancer device for an internal combustion engine according to claim 1,
The balancer device for an internal combustion engine, wherein the oil discharge hole is provided on an upper side of the housing in the direction of gravity.
(A) In the balancer device for an internal combustion engine according to claim 1,
The balancer device for an internal combustion engine, wherein the oil discharge hole is opened from the counterweight in a direction in which centrifugal force acts.

Since the oil in the housing is scraped up by the counterweight and scattered in the centrifugal direction, the oil is easily discharged into the oil pan from the oil discharge hole.
(C) In the balancer device for an internal combustion engine according to claim 1,
The balancer device for an internal combustion engine, wherein the oil discharge hole is formed to open from an outer peripheral edge of the counterweight along a tangential extension direction in a rotation direction.

The oil scooped up with the rotation of the counterweight is scattered in the tangential extension direction of the counterweight rotation direction, so that the discharge efficiency into the oil pan from the oil discharge hole formed here is improved. .
(D) In the internal combustion engine balancer device according to claim 1,
A balancer device for an internal combustion engine, characterized in that an extension portion extending outward from a lower side of the oil discharge hole in the gravity direction is provided above the oil discharge hole in the gravity direction.

The oil scraped up by the counterweight and scattered in the direction of the oil discharge hole hits the lower surface of the extension portion and is guided as it is into the oil pan, so that the oil discharge performance is further improved.
(E) The balancer device for an internal combustion engine according to claim 1,
The internal combustion engine is characterized in that the oil strainer is biased from a central position between the driving rotating body and the driven rotating body toward one of the rotating bodies located on the lower side in the gravitational direction. Balancer equipment.
(F) The internal combustion engine balancer device according to claim 3,
The drive rotator and the driven rotator are respectively arranged so that the center of rotation is on the upper and lower sides in the direction of gravity, and any one of the rotators disposed on the lower side in the direction of gravity in the housing stops driving the engine. A balancer device for an internal combustion engine, characterized in that it is sometimes positioned below the oil level in the housing.
(G) In the internal combustion engine balancer device according to claim 3,
The balancer device for an internal combustion engine, wherein the drive rotator and the driven rotator are arranged below the oil level of the oil in the housing when the engine is stopped.

  Since the height of the oil pan can be reduced as much as possible, the vertical height of the entire internal combustion engine can be reduced, and the degree of freedom of layout in the engine room is improved.

  Moreover, since each journal part in the housing of a drive rotary body and a driven rotary body will be in the state immersed in oil, the lubricity of this journal part improves.

DESCRIPTION OF SYMBOLS 1 ... Cylinder block 2 ... Crankshaft 3 ... Ladder frame 4 ... Oil pan 5 ... Crank gear 6 ... Balancer device 7 ... Balancer housing 8 ... Drive side balancer shaft (drive rotator)
9 ... Driver side balancer shaft (driven rotor)
DESCRIPTION OF SYMBOLS 10 ... Drive side gear 11 ... Driven side gear 13 ... Lower housing 14 ... Upper housing 14a ... Upper wall part (extension part)
19a, 19b ... Bearings 21a, 21b ... Drive side counterweights 24a, 24b ... Driven side counterweights 33 ... Oil strainer O ... Oil L ... Oil level X ... Center line

Claims (3)

A driving rotating body to which rotational force is transmitted from the crankshaft;
A driven rotator to which a rotational force is transmitted from the drive rotator;
A housing that is attached to the internal combustion engine in a state of being inclined in the direction of gravity in the oil pan, and that rotatably accommodates the drive rotating body and the driven rotating body in which the rotational axes are arranged above and below in the direction of gravity; ,
An oil strainer provided on the lower surface of the gravitational direction at a position biased toward one of the rotating bodies arranged on the lower side of the housing in the gravitational direction;
An oil pump that is provided in the housing and is rotationally driven by the driving rotating body or the driven rotating body and sucks oil in the oil pan from the oil strainer and supplies it to the sliding portion of the engine,
The housing is formed with an oil discharge hole for discharging oil in the housing into the oil pan at a position on the other rotating body side located on the upper side in the gravity direction, and on the lower side in the gravity direction. A balancer device for an internal combustion engine, wherein the periphery of one of the rotating bodies located at the side is closed. A balancer device for an internal combustion engine attached to the internal combustion engine in a state inclined downward with respect to the direction of gravity in the oil pan,
A driving rotating body to which rotational force is transmitted from the crankshaft;
A driven rotator to which a rotational force is transmitted from the drive rotator;
A housing that rotatably accommodates the drive rotator and the driven rotator therein;
An oil strainer provided on the lower surface in the gravitational direction of the housing and biased to the lower side of the gravitational direction in the inclined direction;
An oil pump for supplying the oil sucked from the oil strainer to the drive part side of the internal combustion engine,
The balancer device for an internal combustion engine, wherein an oil discharge hole for discharging oil in the housing into the oil pan is formed only at a position biased upward in the gravitational direction of the inclination direction of the housing. A balancer device for an internal combustion engine attached to the internal combustion engine in a state inclined downward with respect to the direction of gravity in the oil pan,
A driving rotor having a counterweight to which a rotational force is transmitted from the crankshaft;
A rotational force is transmitted from the drive rotator, and a driven rotator having a counterweight;
A housing that rotatably accommodates the drive rotator and the driven rotator therein;
An oil strainer provided on the lower surface of the housing in the direction of gravity;
An oil pump for supplying oil sucked from the oil strainer to a drive part of the internal combustion engine,
The housing has an oil discharge hole for draining oil to an upper portion in the gravitational direction with respect to the oil surface inside the housing while the lower portion in the gravitational direction is submerged in the oil in the oil pan when the engine is stopped. Form the
On the other hand, a balancer device for an internal combustion engine, wherein the oil strainer is disposed at a position biased diagonally with respect to the oil discharge hole.

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