JP2014109358A - Balancer device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balancer device which can reduce the drive loss and the size.SOLUTION: When a first shaft 23 is rotated to the left direction within the range of 90° from the state shown in Fig.6 (a), first and second sliders 25 and 26 and a second shaft 24 are rotated at the same angular velocity as the first shaft 23, as shown in Fig.6 (b)-(e), and a connection support shaft 43 supporting an external gear 27, that is, an Oldham center O3, turns on a circle C0 having a balancer center O as a turning center at the angular velocity twice the first and the second sliders 25 and 26. The external gear 27 supported by the connection support shaft 43 is meshed with an internal gear 52 whose number of teeth is twice, and rotates to a direction opposite from the first shaft 23, that is, the right direction, at the angular velocity twice, and a balance weight 28 is raised to the uppermost part in accordance with turning and rotating of the external gear 27.

Description

  The present invention relates to a balancer device attached to an engine for automobiles and the like, and more particularly to a technique for realizing reduction in driving loss, downsizing, and the like.

In reciprocating internal combustion engines (hereinafter referred to as engines) for automobiles, vibrations caused by the movement of pistons and connecting rods (particularly secondary vibrations in inline 2-cylinder and inline 4-cylinder engines that cannot be removed by the counterweight of the crankshaft) In many cases, a balancer type balancer device is installed. In this type of balancer device, a pair of balancer shafts (shafts having eccentric weights) are installed on the sides of the cylinder and below the cylinder block (for example, in the oil pan), and these balancers have a rotational speed twice that of the crankshaft. Secondary vibration is canceled by rotating the shafts in opposite directions (see Patent Documents 1 and 2).
JP 2005-30432 A Japanese Patent No. 3646091

  The balancer apparatus described above has various problems as described below. In other words, the two balancer shafts rotate at twice the number of rotations of the crankshaft, but this is an impediment to the adoption of needle roller bearings with low drive loss. The sum of the drive loss (friction loss) in the case of this is a magnitude that cannot be ignored. Further, since both balancer shafts rotate in opposite directions, it is necessary to incorporate a mechanism such as a reversing gear in the balancer device, resulting in an increase in the number of parts and an increase in cost and weight. In addition, when the balancer shaft is disposed on the side of the cylinder, the layout of an exhaust purification device (diesel particulate filter, oxidation catalyst, EGR cooler, etc.) such as a diesel engine becomes difficult. In an engine in which the balancer shaft also serves as the drive shaft of the oil pump, the oil pump operates at a high speed (for example, 10,000 rpm or more) that exceeds twice the rotational speed of the crankshaft, and the oil pump charging efficiency Decrease.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a balancer device that realizes reduction in drive loss, compactness, and the like.

  According to a first aspect of the present invention, there is provided a balancer device (21) attached to a single cylinder, in-line two-cylinder, in-line four-cylinder internal combustion engine (1), the housing (22) constituting the outer shell of the device, and the housing And is arranged parallel to the crankshaft (11) of the internal combustion engine on a plane (Sh) including each cylinder axis of the internal combustion engine, and at the same speed as the crankshaft by the crankshaft. A first shaft (23) to be driven, rotatably held by the housing, disposed on the plane in parallel with the crankshaft, and having a predetermined offset amount (L) with respect to the first shaft. The offset second shaft (24), and the first shaft and the second shaft are interposed between the first shaft and the second shaft. An orthogonal Oldham joint is constructed in cooperation with hubs provided in the shafts, and passes through the axis of the first shaft and the axis of the second shaft, along a circle whose diameter is the offset amount. Formed in the housing, a rotating slider (25, 26), an external gear (27) which is supported by the slider so as to be rotatable about the axis (O3) of the slider, and which has the offset amount as a reference circular diameter. An internal gear (52) meshing with the external gear with the center of rotation (O) of the slider as the center (O) and a reference circle diameter of twice the offset amount, and the external gear. A balance weight (28) having a center of gravity at a position on the reference circle diameter of the gear and on the plane that cancels the secondary inertial force of the internal combustion engine.

  In the second aspect of the present invention, the first shaft and the second shaft are supported by the housing via rolling bearings (31, 34), respectively.

  In the third aspect of the present invention, the external gear is supported by the slider via a rolling bearing (51).

  According to the first aspect of the present invention, since the first and second shafts and the slider rotate at the same speed as the crankshaft, the sum of drive loss at the bearing support portion is reduced, and the oil pump on the first shaft. In the case where the drive shaft is also used, the number of rotations of the oil pump is lowered and drive loss is suppressed. Further, according to the second and third aspects, the driving resistance of the balancer device is reduced, and the driving loss is suppressed.

It is the perspective view which saw through the principal part of the engine which concerns on embodiment. It is a longitudinal section of the balancer device concerning an embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a disassembled perspective view of the balancer apparatus which concerns on embodiment. It is a simplification figure showing the relation of each element member concerning an embodiment. It is explanatory drawing which shows the action | operation of the balancer apparatus which concerns on embodiment. It is explanatory drawing which shows the action | operation of the balancer apparatus which concerns on embodiment. It is a schematic diagram which shows the motion of the slider center which concerns on embodiment.

  Hereinafter, an embodiment in which the present invention is applied to an automobile engine balancer device will be described in detail with reference to the drawings. In the description of the embodiment, front and rear, left and right, and top and bottom are indicated by arrows in FIG. 1, and the position and direction of each member will be described along this.

<< Configuration of Embodiment >>
As shown in FIG. 1, the engine 1 of this embodiment is a DOHC 4-valve type in-line four-cylinder gasoline engine (hereinafter simply referred to as an engine) mounted on an automobile, and includes a cylinder block 2, a cylinder head 3, and a cam cover 4. The outer shell is composed of the oil pan 5 and the like. A crankshaft 11 is rotatably supported at the lower part of the cylinder block 2, and a piston 13 connected to the crankshaft 11 via a connecting rod 12 reciprocates up and down in a cylinder bore formed in the cylinder block 2. . An intake camshaft 15 and an exhaust camshaft 16 that are rotationally driven by the crankshaft 11 are supported on the cylinder head 3, and these camshafts 15, 16 open and close the pair of intake valves 17 and exhaust valves 18.

<Balancer device>
The balancer device 21 is installed below the crankshaft 11 (that is, in the oil pan 5), and a drive gear 19 attached to the front end of the crankshaft 11 and a driven gear that meshes with the drive gear 19 with the same number of teeth. 20, the crankshaft 11 is rotationally driven in the reverse direction at the same rotational speed.

  As shown in FIGS. 2 to 4, the balancer device 21 includes a housing 22 constituting the outer shell of the device, first and second shafts 23 and 24 held by the housing 22, and interposed between the shafts 23 and 24. The first and second sliders 25 and 26, the external gear 27 held between the sliders 25 and 26, and a pair of front and rear balance weights 28 formed integrally with the external gear 27 are main components. The first and second shafts 23 and 24 are arranged in parallel with the crankshaft 11, and each axis O1 and O2 includes a surface Sh including the center line of each piston 13 (that is, including each cylinder axis). On the plane). Further, the balance weight 28 is disposed at an intermediate position (between the second cylinder and the third cylinder) of the crankshaft 11 in the cylinder row direction.

  The first shaft 23 is rotatably supported by the housing 22 via a needle roller bearing 31, and the above-described driven gear 20 is fixed to the front end of the first shaft 23, while the disk-shaped first hub having a groove 32 on the rear surface. 33 is integrated at its rear end. The second shaft 24 is rotatably supported by the housing 22 via a needle roller bearing 34, and is offset from the first shaft 23 with an offset amount L downward on the surface Sh. A disc-shaped second hub 36 having a groove 35 is integrated at the front end thereof.

  The first slider 25 has a disk shape in which a protrusion 41 slidably fitted in the groove 32 of the first hub 33 protrudes from the front surface, and has a serration 42 on the outer periphery of the rear end portion. A shaft 43 projects from the center of the rear surface. Further, the second slider 26 has a disk shape in which a protrusion 45 slidably fitted in the groove 35 of the second hub 36 protrudes on the rear surface, and the serration 42 of the connection support shaft 43 is press-fitted. Serration hole 46 is formed in the center. The first slider 25 and the second slider 26 are firmly integrated by pressing the serration 42 of the connection support shaft 43 into the serration hole 46.

  The projections 41 of the first slider 25 and the projections 45 of the second slider 26 are 90 ° apart from each other in the axial direction, and the first and second hubs 33 and 36 and the first and second sliders 25, 26 constitutes an orthogonal Oldham joint. As shown in FIG. 5, the centers of the first and second sliders 25 and 26 (that is, the axis of the connecting support shaft 43: hereinafter referred to as Oldham center O3) are the first and second shafts 23 and 24. A center point O (hereinafter referred to as a balancer center O) of a line segment connecting the axial centers O1 and O2 of the first and second shafts 23 and 24 along a circle C0 passing through the axial centers O1 and O2. Turn.

  The external gear 27 is rotatably supported by the connection support shaft 43 via a needle roller bearing 51 and meshes with an internal gear 52 formed integrally with the intermediate wall 29 of the housing 22. As shown in FIG. 5, the external gear 27 has a reference circle C1 having a diameter (reference circle diameter D1) and a number of teeth (not shown in FIG. 3) of the reference circle C2 of the internal gear 52 (reference circle). The diameter D2) and the number of teeth (not shown in FIG. 3) are set to ½, and when the first and second sliders 25 and 26 rotate in either the left or right direction, It rotates in the reverse direction with a rotation speed twice that of 26. The center of the reference circle C2 of the internal gear 52 coincides with the balancer center O, and thus the balancer center O is always located on the reference circle C1 of the external gear 27.

  Both balance weights 28 are disk-shaped formed in contact with both end faces of the external gear 27 so as to generate an inertial force that cancels secondary vibration caused by the movement of the piston 13 and the connecting rod 12. Is set to the mass. As shown in FIGS. 3 and 5, the center of gravity G of both balance weights 28 is located on the reference circle C1 of the external gear 27, and the state shown in FIGS. In a state where the top dead center, the second and third pistons 13 are at the bottom dead center, and the external gear 27 is located at the lowermost position of the reference circle C2, the center of gravity G is located at the bottom. An annular thrust bearing 55 (see FIG. 4) is interposed between the first and second sliders 25 and 26 and the balance weights 28, respectively.

<< Operation of Embodiment >>
When the engine 1 is started, as described above, the driven gear 20 (that is, the first shaft 23) driven by the drive gear 19 rotates in the reverse direction at the same rotational speed as that of the crankshaft 11, and FIG. 6 and FIG. As shown, the balancer device 21 begins to operate.

  In the balancer device 21, when the first shaft 23 rotates 90 ° in the left direction from the state of FIG. 6A (that is, the state of FIGS. 1 to 5), the balancer device 21 is shown in FIGS. As described above, the first and second sliders 25 and 26 and the second shaft 24 also rotate at the same angular velocity as that of the first shaft 23, and the connection support shaft 43 supporting the external gear 27 (that is, Oldham center O3) is a balancer. It turns on the circle C0 centering on the center O with an angular velocity twice that of the first and second sliders 25 and 26. Then, since the external gear 27 supported by the connection support shaft 43 meshes with the internal gear 52 having twice the number of teeth, the external gear 27 is doubled in the direction opposite to the first shaft 23 (that is, in the right direction). It rotates with an angular velocity, and the center of gravity G of the balance weight 28 rises to the top as the external gear 27 turns and rotates.

As shown in FIG. 8, the axis O1 of the first shaft 23 is A, the axis O1 of the second shaft 24 is B, the Oldham center O3 is C, the right end of a horizontal line passing through B is D, and the connection support shaft Assuming that the turning angle of 43 is θ (ωt), ∠ACB is 90 °, and ΔAOC and ΔCOB are both isosceles triangles, so that ∠CBD is θ and ∠COB is 2θ according to the following equation.
∠CBD = 90 °-(90 ° -θ)
∠COB = 180 ° − (180 ° −2θ) = 2θ

Since the trajectory of the balance weight 28 is an internal cycloid (hypocycloid curve) trajectory, assuming that the reference circle diameter D1 of the external gear 27 is d and the reference circle diameter D2 of the internal gear 52 is 2d, coordinates (x , Y) is obtained by the following equation.
x = (d−d / 2) cos θ + (d / 2) · cos ((d−d / 2) θ / (d / 2)) = d cos θ
y = (d−d / 2) sin θ−sin ((d−d / 2) / (d / 2) θ) = 0
Thus, although the balance weight 28 moves in the vertical direction, the balance weight 28 does not move as a harmonic vibration of 2ωt in the horizontal direction.

  On the other hand, in the balancer device 21, when the first shaft 23 is further rotated 90 ° leftward from the state shown in FIG. 7A (ie, the state shown in FIG. 6E), the balancer device 21 is changed to FIG. ), The first and second sliders 25 and 26 and the second shaft 24 also rotate at the same angular velocity as the first shaft 23, and the connection support shaft 43 supporting the external gear 27 (that is, Oldham center O3). ) Turns on the circle C0 with the balancer center O as the turning center at an angular velocity twice that of the first and second sliders 25 and 26. Then, since the external gear 27 supported by the connection support shaft 43 meshes with the internal gear 52 having twice the number of teeth, the external gear 27 is doubled in the direction opposite to the first shaft 23 (that is, in the right direction). It rotates at an angular velocity, and the center of gravity G of the balance weight 28 descends to the lowest position as the external gear 27 turns and rotates.

  As described above, in the balancer device 21 of the present embodiment, the balance weight 28 moves up and down twice in the surface Sh while the crankshaft 11 makes one rotation, so that the secondary inertia force accompanying the vertical movement of the piston 13 is increased. cancel. And since the rotation speed of the 1st, 2nd shafts 23 and 24 is the same as the rotation speed of the crankshaft 11, the friction loss in a support part (needle roller bearings 31 and 34) decreases, and the drive loss of the engine 1 is reduced. Reduced. Further, when the first shaft 23 is also used as the drive shaft of the oil pump, the rotation speed of the oil pump is suppressed to be the same as the rotation speed of the crankshaft 11, and an effect of improving the filling efficiency of the oil pump is obtained.

  This is the end of the description of specific embodiments. However, aspects of the present invention are not limited to these embodiments. For example, in the above-described embodiment, the present invention is applied to a balancer device for an in-line four-cylinder engine mounted on an automobile, but the present invention is naturally applicable to a single-cylinder engine or an in-line two-cylinder engine. Further, the balancer device of the above embodiment has one set of balance weights in the center of the cylinder direction of the in-line four-cylinder engine, but may have two sets or four sets of balance weights. If there are four balance weights, the balance weights may be arranged between the first cylinder and the second cylinder and between the third cylinder and the fourth cylinder. What is necessary is just to arrange each balance weight. In the above embodiment, the first shaft is rotated in the opposite direction to the crankshaft via the gear. However, the first shaft may be rotated in the same direction as the crankshaft via the chain. In addition, the overall configuration of the balancer device, the shape of each component, and the like can be changed as appropriate without departing from the spirit of the present invention.

1 engine (internal combustion engine)
DESCRIPTION OF SYMBOLS 11 Crankshaft 13 Piston 21 Balancer apparatus 22 Housing 23 1st shaft 24 2nd shaft 25 1st slider 26 2nd slider 27 External gear 28 Balance weight 31 Needle roller bearing (rolling bearing)
34 Needle roller bearings (rolling bearings)
51 Needle roller bearings (rolling bearings)
52 Internal gear

Claims (3)

A balancer device attached to a single cylinder, in-line 2-cylinder, in-line 4-cylinder internal combustion engine,
A housing constituting the outer shell of the device;
A first shaft that is rotatably held by the housing, is disposed in parallel with the crankshaft of the internal combustion engine on a plane including the cylinder axes of the internal combustion engine, and is driven at the same speed as the crankshaft by the crankshaft. One shaft,
A second shaft that is rotatably supported by the housing, is disposed in parallel with the crankshaft on the plane, and is offset with a predetermined offset with respect to the first shaft;
An orthogonal Oldham joint is configured in cooperation with hubs provided between the first shaft and the second shaft, and provided with the first shaft and the second shaft, respectively. A slider that passes through an axis and the axis of the second shaft, and that rotates along a circle whose diameter is the offset amount;
An external gear that is supported by the slider so as to be rotatable about the axis of the slider and has the offset amount as a reference circle diameter;
An internal gear that is formed in the housing and that meshes with the external gear with a reference circle diameter that is twice the offset amount, centered on the turning center of the slider;
A balance weight formed on the external gear, on a reference circle diameter of the external gear and on the plane, and having a center of gravity at a position that cancels the secondary inertia force of the internal combustion engine. And balancer equipment.   2. The balancer device according to claim 1, wherein the first shaft and the second shaft are respectively supported by the housing via rolling bearings.   The balancer device according to claim 1 or 2, wherein the external gear is supported by the slider via a rolling bearing.

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