JP2002081504A - Balancer device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a manufacturing cost and the size of a device by simplifying a feed passage for lubricating radial bearings and thrust bearings. SOLUTION: Metal bearings 15a and 15b of radial type are disposed in the supporting walls 13a and 13b of upper and lower blocks 2 and 3 forming a housing 1. A thrust bearing surface 18 is provided continuously on the axial both sides of the journal part 11 of a balancer shaft 4. A thrust bearing surface 21 in contact with the thrust bearing surface 18 of the balancer shaft 4 is provided on the axial both sides of the supporting wall 13b at a metal bearing 15b disposing position. A lubricating oil feed port 23 is disposed at a position facing the metal bearings 15a and 15b in the supporting walls 13a and 13b. The lubricating oil fed to the metal bearings 15a and 15b through the feed port 23 is circulated from the side part of the metal bearing 15b to a clearance between the thrust bearing surface 18 and the thrust bearing surface 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer device attached to an engine used in a vehicle or the like and for canceling vibrations caused by rotational imbalance of a crankshaft.

[0002]

2. Description of the Related Art In a balancer device of this type, a balancer shaft having a balance weight is mounted on a housing via a radial bearing and a thrust bearing, and the balancer shaft is rotated synchronously by receiving the power of a crankshaft. The vibration caused by the rotational imbalance of the shaft is canceled by the eccentric rotation of the balance weight.

Since the balancer shaft always rotates at a high speed together with the crankshaft, radial bearings and thrust bearings for supporting the balancer shaft are lubricated by lubricating oil supplied from the outside.

Incidentally, this technique is disclosed in, for example,
27939.

[0005]

However, in the above-mentioned conventional balancer device, since the radial bearing and the thrust bearing are arranged at positions separated in the axial direction of the balancer shaft, the lubricating oil is separately provided for each bearing. The supply passage must be formed, and as a result, the internal structure of the device becomes complicated, and there is a concern that the manufacturing cost will increase and the device will be enlarged.

Accordingly, the present invention provides an engine balancer device capable of simplifying the structure of a supply passage for lubricating a radial bearing and a thrust bearing, thereby reducing manufacturing costs and miniaturizing the device. What you want to do.

[0007]

As a means for solving the above-mentioned problems, according to the first aspect of the present invention, a balancer shaft having a balance weight is rotatably supported by a housing via a radial bearing and a thrust bearing. In a balancer device for an engine, the balancer shaft is configured to rotate synchronously with a crankshaft. In the engine balancer device, a thrust support surface is continuously provided on both axial sides of a journal portion supported by the radial bearing of the balancer shaft, and a housing is provided. Thrust bearing surfaces opposing the thrust support surface of the balancer shaft are provided on both axial sides of the radial bearing arrangement position, and the lubricating oil supply port is arranged at a position facing the radial bearing of the housing or the balancer shaft. .

In the case of the present invention, the lubricating oil introduced into the supply port is supplied to the radial bearing, then wraps around the journal in both axial directions, and is supplied between the thrust support surface and the thrust bearing surface.

According to a second aspect of the present invention, balance weights are disposed on both axial sides of the journal portion of the balancer shaft,
A thrust support surface is provided on the side of the journal portion side of the balance weights, and a thrust bearing surface is provided on the housing so as to contact the thrust support surfaces. The thrust support surface of the balancer shaft and the thrust bearing surface of the housing are arranged in a radial direction. On the outside, step-shaped facing surfaces that face each other with a predetermined gap are provided.

In the case of the present invention, the amount of lubricating oil supplied between the thrust support surface and the thrust bearing surface is limited by the gap between the radially outer stepwise facing surfaces, so that the thrust bearing portion is always sufficient. Lubricating oil is supplied.

According to a third aspect of the present invention, the step-shaped opposing surfaces formed on the side surfaces of the two balance weights are such that the width between the two opposing surfaces is wider than the width between the thrust support surfaces of the two balance weights. And the stepped facing surface on the housing side is formed so that the width between the two facing surfaces is also larger than the width between the thrust bearing surfaces.

In the case of the present invention, the width of the balance weight increases stepwise toward the outside in the radial direction, and the width of the balance weight decreases stepwise at the base of the thrust bearing.
Therefore, when the mold is formed, both the balancer shaft and the housing have good mold release properties.

According to the invention described in claim 4, the housing is divided into an upper block and a lower block, and the thrust bearing surface is formed on only one of the upper block and the lower block.

In the case of the present invention, since the thrust bearing surface requiring high processing accuracy is formed on only one of the upper block and the lower block, the processing itself of the housing is facilitated and the blocks are easily assembled with each other. Become.

[0015]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG.

FIG. 2 is an exploded perspective view of a balancer device according to the present invention. As shown in FIG. 2, the balancer device has a box-shaped housing 1 attached to a lower surface of an engine body (not shown). An upper block 2 and a lower block 3 are divided into two parts, and two balancer shafts 4 and 5 having substantially the same shape are mounted in parallel between the two blocks 2 and 3.

Helical gears 6 and 7 having the same number of teeth are mounted on the outer peripheral surfaces near the front ends of the balancer shafts 4 and 5, respectively, and the two balancer shafts 4 and 5 are engaged with each other to form the balancer shafts 4 and 5. It rotates in the opposite direction. A driving sprocket 8 is attached to the front end of one of the balancer shafts 4 by bolts 9, and the power of the crankshaft is transmitted to the driving sprocket 8 via a chain (not shown) at a one-to-two rotation ratio. It is supposed to be. Therefore, one balancer shaft 4 receives the power of the crankshaft and rotates synchronously with the same shaft, and the other balancer shaft 5 receives the driving force of the one balancer shaft 4 and rotates synchronously in the reverse rotation direction. Since one balancer shaft 4 and the other balancer shaft 5 have substantially the same configuration except for the above, only one balancer shaft 4 will be described below, and the other balancer shaft 5 will be described in detail. It shall be omitted.

The balancer shaft 4 is provided with a first journal portion 10 and a second journal portion 11 on an outer peripheral surface at a front end portion and an outer peripheral surface near a rear portion, respectively. As shown in FIG. Reference numeral 11 denotes metal bearings 14a, 14b and 15a, 1 having a half-split structure on the support walls 12a, 12b of the upper block 2 and the lower block 3, and 13a, 13b.
It is rotatably supported via 5b. The metal bearings 14a, 14b and 15a, 15b constitute a radial bearing. The metal bearings on the first journal portion 10 side are formed to have a smaller axial width than those on the second journal portion 11 side. (L _f <L _r ).

The second journal portion 1 of the balancer shaft 4
A pair of balance weights 16 and 1 are provided before and after in the axial direction.
6 are formed integrally. This balance weight 1
6, the half and the other half are formed in an irregular shape with a plane passing through the axial center interposed therebetween, and the half has a large diameter portion and a substantially circular portion 16a having a sufficient axial width, The other half is provided with a small semicircular portion 16b having both a smaller diameter and a smaller axial width than the majority circular portion 16a. The small semicircular portion 16b is biased toward the second journal portion 11 and is formed to have a larger diameter than the journal portion 11, and the end face of the journal portion 11 is almost flush with the end face of the circular portion 16a. Is formed.

Further, a step-shaped depression 17 is provided on the end face of the mostly circular portion 16a on the side of the second journal portion 11 substantially along the arc of the outer semicircle. The portion left on the end face of the mostly circular portion 16a is the small semicircular portion 1
6b together with the end face 6b. The annular flat surface 18 constitutes a thrust support surface on the balancer shaft 4 side in the present invention, and the recess 17
Constitutes a step-like facing surface. Hereinafter, the annular flat surface 18 will be referred to as the thrust support surface 18, and the depression 17 will be referred to as the step-shaped facing surface 17.

On the other hand, the upper block 2 and the lower block 3
Semi-circular bearing accommodating portions 19a, 19b and 20a, 2 for accommodating metal bearings 14a, 14b and 15a, 15b, respectively, on the supporting walls 12a, 12b and 13a, 13b.
0b is provided, but the thrust support surface 18 of the balancer shaft 4 is provided on the support wall 13b on the rear side of the lower block 3.
A thrust bearing surface 21 is provided in contact with the thrust bearing surface 21. The thrust bearing surface 21 is formed along the circular arc at the edge of the bearing accommodating portion 20b of the side surface of the support wall 13b, and the outer peripheral side of the circular arc is stepwise raised one step. The step portion constitutes a step-shaped facing surface 22 on the housing side in the present invention, and when the balancer shaft 4 is mounted on the housing 1 (lower block 3), the facing surface 22 becomes the step-shaped facing surface 22 on the balancer shaft 4 side. It faces the facing surface 17 with a predetermined gap.

The support wall 13a on the upper block 2 side is not provided with a thrust bearing surface.
The side surface a is set so that the balancer shaft 4 is not always in contact with the thrust support surface 18 or the step-shaped facing surface 17 on the balancer shaft 4 side when the balancer shaft 4 is assembled to the housing 1.

The upper block 2 and the lower block 3
The lubricating oil supply port 23 is provided in the bearing accommodating portions 19a, 19b, and 20a, 20b, and the lubricating oil supplied from an oil pump (not shown) is supplied through the metal port 14a, 14b, and , 15a and 15b. Then, the metal bearings 14a,
A plurality of communication holes 24 penetrating in the radial direction are formed in 14b and 15a, 15b, and the lubricating oil introduced into the supply port 23 is supplied through the communication holes 24 to the metal bearings 14a. It can be supplied in between.

The upper block 2 and the lower block 3 have front and rear support walls 12a, 12b and 13 with the balancer shafts 4, 5 and the like mounted therebetween.
The parts a and 13b are fastened by three bolts 25 and 26, respectively. The bolts 25 and 26 used here have different tensile strength and fastening axial force between the rear side and the front side. Both the strength and the axial force are expressed by the following equations (1) and (2). The rear side is set to be larger as shown in FIG. Where σ _f and σ _r indicate the tensile strength of the front and rear bolts 25 and 26, respectively, and F _f ,
F _r denote the fastening axial force of the bolts 25, 26 of the front side and rear side.

[0025]

Σ _f <σ _r (1)

[0026]

F _f <F _r (2) That is, the balance weight 16 is provided on the rear support wall 13a,
13b, the supporting walls 13a, 1
To act large load constantly in the vicinity 3b, the rear side of the support wall 13a, the tensile strength sigma _r and the fastening axial force F _r of the bolt 26 and 13b must be increased, whereas the front side of the support wall Since the input load is small near 12a, 12b, the bolt 25 of the front support walls 12a, 12b is set to have a smaller tensile strength σ _f and a fastening axial force F _f than the bolt 26 of the rear support walls 13a, 13b. Have been. In the case of this embodiment, since the bolts 25 having small tensile strength and fastening axial force are used as the bolts 25 of the front support walls 12a and 12b, the overall cost can be reduced.

As described above, the metal bearings 14a, 14b at the front end of the balancer shaft 4 are replaced with the metal bearings 15 at the rear.
The reason why the width in the axial direction is narrower than that of a and 15b is for the same reason. In other words, the front metal bearings 14a, 14b have a smaller input load than the rear metal bearings 15a, 15b, so that no problem occurs even if the axial width is reduced, but rather friction during rotation. Can be further reduced.

The balancer device configured as described above,
When the rotation of the crankshaft is input to the balancer shaft 4 via the driving sprocket 8, the balance weight 16 rotates eccentrically with the balancer shaft 4, and the balance weight 16 is also reversed to the other balancer shaft 5 via the helical gears 6 and 7. The direction rotation is transmitted, and the balance weight 16 of the balancer shaft 5 rotates eccentrically in the opposite direction.

At this time, the rotation of both balancer shafts 4 and 5 cancels the vertical vibration of the engine caused by the rotational imbalance of the crankshaft.
The horizontal vibrations accompanying the rotation of 5 cancel each other out as they rotate in opposite directions.

At this time, metal bearings 14a, 14b supporting the balancer shafts 4, 5 and 15a, 15b
The lubricating oil is supplied to the thrust bearing surface 21 and the metal bearings 14a and 14b, and the lubricating oil is supplied to the metal bearings 15a and 15b from the supply ports 23 of the bearing accommodating portions 20a and 20b of the housing 1. Between the surface 18 and the thrust bearing surface 21, the lubricating oil flowing out from both sides of the metal bearings 15a and 15b is supplied while flowing around as it is.

Therefore, in this balancer device, it is not necessary to provide a dedicated supply passage for each of the metal bearings 15a and 15b and the thrust bearing surface 21, so that the passage structure is simplified and the production at low cost is realized. be able to.

Further, in this balancer device, since the depression (step-like facing surface 17) is provided in the peripheral region of the end surface of the most circular portion 16a of the balance weight 16, the thrust bearing surface 2
1 has a well-balanced annular shape, and the friction is also kept small. However, in this way the majority of the yen
When the radial width of the thrust bearing surface 21 is reduced by providing a recess in the thrust bearing surface 6a, the lubricating oil flowing between the thrust bearing surface 21 and the thrust support surface 18 when the balancer shafts 4, 5 rotate at a high speed or the like. Can easily flow outward due to centrifugal force.

However, in this balancer device, such a problem can be dealt with by forming the step-shaped opposing surfaces 17 and 22 on the radial outside of the thrust support surface 18 and the thrust bearing surface 21, respectively.

That is, the lubricating oil that has flowed between the thrust support surface 18 and the thrust bearing surface 21 from both sides of the metal bearings 15a and 15b is displaced radially outward from the stepped confronting surfaces 17 and 22. The amount of outflow is limited by the gap between the thrust bearing surface 18 and the thrust bearing surface 21 even if the rotation speed of the balancer shafts 4 and 5 increases and the centrifugal force acting on the lubrication oil increases. No spills. Therefore, a sufficient amount of lubricating oil is always introduced between the thrust support surface 18 and the thrust bearing surface 21, and the two are always sufficiently lubricated.

Further, in the case of the balancer device of this embodiment, each balance weight 16 of the balancer shafts 4 and 5 is formed with a step-shaped facing surface 17 so as to increase in width outward in the radial direction, and supports the lower block 3. Since the wall 13b is formed with the step-shaped opposing surface 22 so as to decrease in width toward the base, the step-shaped opposing surfaces 17, 22 are formed when the balancer shafts 4, 5 and the lower block 3 are molded. There is an advantage that no snagging occurs at the site, and therefore the die-cutting property is good.

In this embodiment, the thrust bearing surface 21 which requires high molding accuracy is provided with the lower block 3.
Since the upper block 2 is formed only on the upper block 2, the upper block 2 and the lower block 3 can be easily formed.
Strict assembly accuracy is no longer required. Therefore, the manufacturing cost can be reduced as compared with the case where the thrust bearing surfaces are formed on both the upper block 2 and the lower block 3.

Further, in this embodiment, since the thrust bearing surface 21 and the step-shaped facing surface 22 are formed on the lower block 3 side, the lubricating oil can be sufficiently supplied to these parts by gravity. There are advantages.

[0038]

As described above, the first aspect of the present invention provides
Since the lubricating oil supplied to the radial bearing can be further spilled between the thrust support surface and the thrust bearing surface, there is no need to provide a dedicated supply passage in each bearing portion,
It is possible to reduce the manufacturing cost and the size of the device.

According to the second aspect of the present invention, the outflow of the lubricating oil supplied between the thrust support surface and the thrust bearing surface can be restricted by the gap between the radially outward step-shaped facing surfaces, so that the thrust bearing is provided. Sufficient lubricating oil is always supplied to the parts, and stable lubricating performance can be obtained.

According to the third aspect of the present invention, since the mold removability at the time of molding the balancer shaft and the housing can be improved, the production can be further facilitated and the cost can be further reduced.

According to the fourth aspect of the present invention, since the thrust bearing surface requiring high processing accuracy is formed on only one of the upper block and the lower block of the housing, the processing of the other block can be facilitated. The two blocks can be easily assembled to each other, and as a result, lower cost manufacturing can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, taken along line AA of FIG. 3;

FIG. 2 is an exploded perspective view showing the same embodiment.

FIG. 3 is a front view showing the same embodiment.

FIG. 4 is a bottom view showing the same embodiment.

FIG. 5 is an end view of the same embodiment, taken along line BB of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Upper block 3 ... Lower block 4, 5 ... Balancer shaft 11 ... 2nd journal part (journal part) 15a, 15b ... Metal bearing (radial bearing) 16 ... Balance weight 17, 22 ... Step-shaped facing surface 18 ... thrust support surface 21 ... thrust bearing surface 23 ... supply port

Continued on the front page (72) Inventor Makoto Kawada 1370 Onna, Atsugi-shi, Kanagawa Prefecture Inside Unisia Gex Co., Ltd. (Reference) 3J011 AA07 BA02 JA02 KA04 MA03

Claims (4)

[Claims] A balancer shaft having a balance weight is rotatably supported by a housing via a radial bearing and a thrust bearing, and the balancer shaft is configured to rotate synchronously with a crankshaft. A thrust support surface is provided on both sides in the axial direction of a journal portion supported by the radial bearing of the shaft, and a thrust bearing surface facing the thrust support surface of the balancer shaft on both axial sides of the radial bearing arrangement position of the housing. And a supply port for lubricating oil disposed at a position facing the radial bearing of the housing or the balancer shaft. 2. A balance weight is disposed on both sides of the journal portion of the balancer shaft in the axial direction, and a thrust support surface is provided on the side surface of the balance weight on the journal portion side, while the housing is provided on the both thrust support surfaces. The engine according to claim 1, wherein a thrust bearing surface in contact with the thrust bearing surface is provided, and a step-shaped facing surface that faces the thrust bearing surface of the balancer shaft and the thrust bearing surface of the housing in a radial direction outside with a predetermined gap is provided. Balancer device. 3. The stepped opposing surfaces formed on the side surfaces of the two balance weights are formed so that the width between the two opposing surfaces is wider than the width between the thrust support surfaces of the two balance weights. 3. The engine balancer device according to claim 2, wherein the stepped facing surface is formed such that the width between the two facing surfaces is also larger than the width between the thrust bearing surfaces. 4. The engine according to claim 1, wherein the housing is divided into an upper block and a lower block, and the thrust bearing surface is formed on only one of the upper block and the lower block. Balancer equipment.