JPH1068445A - Balancer shaft for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply change the characteristics of a balancer shall different by the kind of an internal combustion engine by changing the weight of a balancer weight by providing the balancer shaft comprising the balancer weight which is eccentrically fixed inside a cylindrical member and a lid to cover each end of the cylindrical member. SOLUTION: Each end of a cylindrical pipe 12 to form the contour of a balancer shaft 10 is covered by lids 20, 30, and the lids 20, 30 are fixed to an inner circumference of the pipe 12 through press-fitting or brazing. A weight 40 to off-center the weight distribution of the balancer shaft 10 made of a filled pipe is stored in the pipe 12. Acceptance holes 22, 32 of the size capable of accepting projected parts 42, 44 formed in a center part on each end of the weight 40 are provided inside the lids 20, 30, and the acceptance holes 22, 32 are provided at the position away from the center of the lid 20 so that the weight distribution in the radial direction of the balancer shaft 10 is eccentric when the weight 40 is fixed in the balancer shaft 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating internal combustion engine, in which vibration generated by a reciprocating member is generated.
The present invention relates to a balancer shaft which is reduced by rotation of an eccentric weighted shaft.

[0002]

2. Description of the Related Art Conventionally, a balancer shaft having an eccentric weight is arranged in parallel with a crankshaft, and this balancer shaft is rotated by the crankshaft to reduce vibrations caused by members such as pistons reciprocating. Techniques related to balancer shafts for internal combustion engines are known. Also, in recent years, by providing a relatively heavy balancer shaft inside the oil pan below the engine, there has been a demand for lowering the center of gravity of the engine to ensure engine stability, and the balancer shaft with eccentric weight has A device that is compatible with a requirement not to cause a loss in output of an internal combustion engine due to rotational resistance of stirring the oil by rotating while immersed in the oil has been studied. For example, Japanese Unexamined Utility Model Publication No. 4-101842 (hereinafter referred to as a first conventional technique) and Japanese Unexamined Patent Application Publication No. 5-231479 (hereinafter referred to as a second conventional technique) satisfy these requirements.

The first prior art discloses a technique in which an eccentric portion formed by casting or the like is covered with a cover around the outer periphery of a balancer shaft that expands outward to make the outer shape of the entire balancer shaft cylindrical. .

[0004] In the second prior art, there is a technique in which a cutout portion of a semi-cylindrical body is provided in the axial direction of the balancer shaft, and the cutout portion is covered with a semi-cylindrical cover to make the outer shape of the balancer shaft cylindrical. It has been disclosed.

[0005]

In the first and second prior arts described above, since the eccentric balancer shaft is formed by casting or the like, a large number of types of internal combustion engines are manufactured. Is the length according to the characteristics of the internal combustion engine,
A balancer shaft having a thickness and an eccentric amount is prepared, and a casting mold is required for each type of the internal combustion engine, so that the balancer shaft cannot be shared.

Further, in the first prior art, the rotational power is transmitted by an eccentric weight balancer shaft, and the outer periphery of the balancer shaft is covered with a cover. In the second prior art, the rotational power is transmitted by a semi-cylindrical balancer shaft having a notch,
A cutout portion of the balancer shaft is formed in the axial direction, and is covered by a semi-cylindrical cover. The covering cover used in the first prior art and the second prior art is attached to a balancer shaft that transmits rotational power, and the covered cover is damaged by centrifugal force of the balancer shaft and rotational resistance in oil. there's a possibility that.

[0007] The present invention discloses a balancer shaft for an internal combustion engine that can be used in common for various internal combustion engines and can achieve stable rotation.

[0008]

According to the first aspect of the present invention, the components constituting the balancer shaft can be shared. That is,
In reducing the vibration generated by the reciprocating member of the internal combustion engine by the rotation of the eccentric weight, the characteristics of the balancer shaft that differs for each type of the internal combustion engine can be easily changed by changing the weight of the balancer weight.
Further, when it is necessary to change the length of the balancer shaft when changing the type of the internal combustion engine, it can be dealt with by changing the length of the cylindrical member. Furthermore, since the rotational power of the balancer shaft is transmitted by the cylindrical material,
The balancer shaft can be rotated stably.

According to the second aspect of the present invention, the balancer weight can be easily assembled, and the balancer weight can be reliably eccentrically fixed.

According to the third aspect of the present invention, a space without a balancer weight can be utilized as an oil passage inside the balancer shaft, and lubricating oil is supplied to a sliding portion when rotating the balancer shaft. Is possible.

According to the invention of claims 4 to 6, the processing is completed only by bending the pipe material as the balancer weight. In particular, the balancer weight can be easily formed by pressing the pipe material. In addition, the processing cost can be reduced.

According to the seventh aspect of the present invention, since the pipe member is used as a passage for sending the lubricating oil for rotating the balancer shaft, the weight of the lubricating oil flowing through the passage is one of the balancer weights of the balancer shaft. It can be used as a unit.

According to the eighth aspect of the present invention, since the balancer weight is fixed with bolts from outside the cylindrical member, the balancer weight can be easily fixed.

According to the ninth aspect of the present invention, since the balancer weight, the cylindrical member, and the core member penetrating substantially at the center of the lid member disposed at both ends of the cylindrical member are fixed with bolts, the balancer of the rotating balancer shaft is fixed. It is possible to stably hold the weight. In addition, it is possible to use the portions protruding to both outsides of the lid member as the rotation axis of the balancer shaft.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a balancer shaft 10 according to a first embodiment of the present invention. Reference numeral 12 denotes a hollow cylindrical pipe member forming the outer shape of the balancer shaft 10. Both ends of the pipe member 12 are closed by lids 20 and 30. The lids 20 and 30 are fixed to the inner periphery of the pipe member 12 by press fitting or brazing. Reference numeral 40 denotes a pipe material whose inside is filled, and the balancer shaft 10
Are weights (balancer weights) for eccentricity of the weight distribution. Protrusions 42 and 44 are formed at the center of both ends of the weight 40. The receiving holes 2 each having a size capable of receiving the convex portions 42 and 44 of the weight 40 are provided inside each of the lids 20 and 30.
2, 32 are provided. The receiving hole 22 is formed so that the weight distribution in the radial direction of the balancer shaft 10 is eccentric when the weight 40 is fixed in the balancer shaft 10.
The cover 20 is provided at a position eccentric from the center. Similarly, the receiving hole 32 is provided at a position eccentric from the center of the lid 30. 2, a space 14 is formed between the inner periphery of the pipe member 12 and the outer periphery of the weight 40.

In the first embodiment, this space 1
4 is used as an oil passage for lubricating between the balancer shaft 10 and a bearing (not shown) when the balancer shaft 10 is rotated. That is, an oil introduction passage 24 is formed in the lid 20,
An oil discharge passage 34 is formed in the lid 30, and the oil introduction passage 24 and the oil discharge passage 34 communicate with the space 14. An oil discharge hole 16 is also formed at the center of the pipe member 12 corresponding to a bearing (not shown). The space 14
The use of the oil balance as an oil passage is appropriately selected depending on the part of the engine to which the balancer shaft 10 is attached. In other words, if the balancer shaft 10 is mounted on the oil pan of the engine, it is driven to rotate in the oil stored in the oil pan, and no lubricating oil is required.

FIG. 3 is a sectional view of a balancer shaft 50 according to a second embodiment of the present invention.
In the second embodiment, in order to reinforce the strength of the pipe member 12 used for the balancer shaft 10 of the first embodiment, the pipe member 12 is divided into two members 12a and 12b, and the weight 40 is also 40a. , 40b. A joint lid 52 is arranged between the pipe members 12a and 12b, and the pipe members 12a and 12b and the weights 40a and 40b are fixed to both ends of the joint lid 52. In the balancer shaft 50, small-diameter portions 28, 38, and 5 having the same shape as the inner circumferences of the pipe members 12 a and 12 b are formed on the lids 26 and 36 and the joint lid 52.
2a, 52b are formed, and the small-diameter portions 28, 38, 52a, 5a
2b is inserted and fixed in the pipe members 12a and 12b. By arranging the lids 26, 36 and the joint lid 52 at positions corresponding to the bearings of the balancer shaft 50, the strength at the time of rotation is secured without supporting the rotation of the balancer shaft 50 with the thin-walled pipe materials 12a, 12b. doing.

FIGS. 4 and 5 show an example in which the balancer shaft 10 according to the first embodiment of the present invention is mounted on a four-cylinder engine. A first balancer shaft 10 and a second balancer shaft 10 (not shown) are provided in the cylinder block 61 of the engine in parallel with the crankshaft 62. A crank pulley 63 and a crank timing pulley 6 are provided at the left end of the crankshaft 62 in the figure.
0 and a sprocket 64 are provided. A timing belt 60a is wound around the crank pulley 60 to rotate a camshaft that opens and closes an intake valve and an exhaust valve of the engine. As shown in FIG. 5, a chain 65 is hung on the sprocket 64, and the chain 65 rotates a sprocket 66 fixed to the first balancer shaft 10 and a sprocket 67 for driving an oil pump. A gear gear is provided on the outer periphery of the sprocket 67, and a gear gear 68 at the end of the second balancer shaft 10 (not shown) is provided.
, The second balancer shaft 10 also rotates. 6
Reference numeral 9 denotes a tensioner, which gives the chain 65 a desired tension. The crankshaft 62 rotates while being supported by a bearing 70 of the cylinder block 61 and a bearing cap 71, and moves up and down a connecting rod 72 connected to a piston (not shown) provided for each cylinder.

As shown in FIG. 4, the first balancer shaft 10 is provided between an oil pan 73 and a partition wall 74 of the oil pan 73, is supported by bearings 75, 76, 77, 78, and is rotated by rotation of a sprocket 66. Rotate.
The bearing 76 is provided with an oil passage 79 communicating with a discharge port of an oil pump (not shown), and guides oil to the oil introduction passage 24 of the cover 20, the space 14, the hole 16, and the oil discharge passage 34 of the cover 30, Lubrication is provided between the pipe member 12 of one balancer shaft 10 and the bearings 75, 76, 77, 78. In addition, the oil for lubrication must be
Ring grooves 76a, 77a, 78a are formed in the bearings 76, 77, 78 along the circumferential direction of the pipe member 12 so as to be supplied to the sliding surface between the bearing 2 and the bearings 75, 76, 77, 78. .

The operation of the thus configured balancer shaft for an internal combustion engine will be described.

When the engine is started, the crankshaft 62 is rotated by the connecting rod 72, and the sprocket 66 is rotated in the clockwise direction in FIG. Then, the gear gear 68 meshing with the sprocket 67 rotates in a direction opposite to the clock. Accordingly, the first balancer shaft 10 fixed to the sprocket 66 and the second balancer shaft 10 (not shown) fixed to the gear 68 rotate in opposite directions. The rotational power of the first and second balancer shafts 10 is generated by the rotation of the pipe member 12, and stable rotation is obtained. Also,
Since the outer shape of the balancer shaft 10 has the cylindrical shape of the integrated pipe member 12, the amount of oil stored in the oil pan 73 increases and the balancer shaft 10 rotates in the oil even if the balancer shaft 10 is immersed. The balancer shaft 10
No breakage occurs. Even if an inertial force is generated by the reciprocating motion of a piston (not shown), the balancer shaft 10,
By canceling the inertial force due to the reciprocating motion of the piston with the inertial force due to the rotation of 10, the engine output loss and the engine vibration can be suppressed.

In the first and second embodiments, the weight 40 of the pipe material filled inside is used as the balancer weight, but the weight 40 of the pipe material is replaced with the weight 40 of the pipe material. Iron iron making the desired weight inside,
It is also possible to enclose a lead or iron ball (for example, a pachinko ball or the like) and braze it to the inner periphery of the pipe member 12 so as to be eccentric and fix it.

Also, for different engine models,
By using the pipe members 12 having different lengths and thicknesses, other members can be commonly used. Moreover,
When changing the length of the pipe material 12, the pipe material 12
It is not necessary to prepare a casting mold of a desired size as in the case of performing casting or the like by adjusting the cutting interval of Can be.

FIG. 6 is a sectional view of a balancer shaft 100 according to a third embodiment corresponding to FIG.
The balancer shaft 100 includes hollow cylindrical pipe members 102 and 104, lids 106 and 108 at both ends, and a joint lid 11.
0, formed from a pipe material 112 serving as a balancer weight. The pipe member 112 includes the lid 106 and the joint lid 11.
Bending portions 114 and 116 are provided at a portion between the cover 108 and the cover 108 and the joint cover 110. Pipe material 1
Numeral 12 penetrates substantially the center of each of the lids 106 and 108 and the joint lid 110 at both ends, and both ends of the pipe member 112 are watertightly closed by plugs 118 and 120. The internal space 122 of the pipe member 112 is an oil passage that lubricates between the pipe member 112 and a bearing (not shown) when the balancer shaft 100 is rotated. 124, 126, 1
28 is a passage for introducing and discharging the lubricating oil.

FIG. 7 shows a state of a pressing step for bending the pipe member 112 when the balancer shaft 100 is manufactured. Prior to the pressing step, the joint lid 110 is inserted into the straight pipe member 112. Then, the pipe member 112 into which the joint lid 110 has been inserted is set in the lower mold 130 of the press. The lower mold 130 is provided with a concave portion 131 for holding the joint lid 110.

The first pressing step includes a pressing upper die 132,
134 and 136 descend so as to hold the pipe member 112. The holding upper mold 134 is provided with a concave portion 135 for holding the joint lid 110. Pressing upper die 13
After 2, 134, 136 hold the pipe material 112,
A second pressing step is performed. That is, as shown in FIG. 7, the punches 138 and 140 descend,
Form 116. FIG. 8 shows bent portions 114 and 116.
As shown in the cross section of FIG.
The flat part 142 crushed by 38 and 140 and the curved part 1 in which the bending rate of the pipe material 112 is increased by the lower mold 130.
44 and a flat shape.

In the second pressing step, since the upper pressing dies 132, 134, and 136 firmly hold the pipe material 112, the punches 138 and 140 are moved by the pipe material 1
When acting on the pipe member 12, both ends of the pipe member 112 are pulled in the direction of the joint lid 110, so that a problem such as a shortening of the pipe member 112 does not occur. Further, the balancer shaft 100 according to the third embodiment has a smaller number of parts than the balancer shaft 50 according to the second embodiment, and can be processed at low cost.

FIG. 9 is a sectional view of a balancer shaft 150 according to a fourth embodiment corresponding to FIG.
The balancer shaft 150 includes hollow cylindrical pipe members 152 and 154, lids 156 and 158 at both ends, and a joint lid 16.
0, core rod 162, weight (balancer weight) 172,
174. The weights 172, 174
The distance between the lid 156 and the joint lid 160 and the lid 158, respectively.
And the length of the gap between the joint cover 160 and the joint cover 160. In addition, weight 17
2, 174 have a shape obtained by dividing a cylinder in the vertical direction as shown in FIG. 10, and bolts 164, 166, 168,
170, the core rod 162 and the pipe members 152, 15
4 is fixed.

The balancer shaft 150 has a weight 17
2, 174 can be fixed with bolts 164, 166, 168, 170 from the outside of the hollow cylindrical pipe members 152, 154, so that the balancer shaft 150 can be easily assembled.

[0031]

According to the first aspect of the present invention, the balancer shaft for an internal combustion engine is a cylindrical member, a balancer weight eccentrically fixed inside the cylindrical member, and a plurality of lid members for closing both ends of the cylindrical member. , It is possible to achieve the common use of the components that constitute the balancer shaft. Further, when the type of the internal combustion engine is changed, it can be dealt with only by changing to a balancer shaft having a different length or thickness. Further, since the rotational power of the balancer shaft is transmitted by the cylindrical member, the balancer shaft can be rotated stably.

According to the second aspect of the present invention, the balancer weight is formed of a bar, and both ends of the bar are held by lids, so that the balancer weight can be easily assembled and fixed. Can be reliably eccentrically fixed.

According to the third aspect of the present invention, one of the lids is provided with an oil introduction hole and the other is provided with an oil discharge hole, so that the balancer weight is provided inside the balancer shaft. It is possible to utilize a space without oil as an oil passage, and to supply lubricating oil to a sliding portion when rotating the balancer shaft.

According to the invention of claims 4 to 6, the processing is completed only by bending the pipe material as the balancer weight, and in particular, the balancer weight can be easily formed by pressing the pipe material. In addition, the processing cost can be reduced.

According to the seventh aspect of the present invention, since the pipe member is used as a passage for sending the lubricating oil for rotating the balancer shaft, the weight of the lubricating oil flowing through the passage is one of the balancer weights of the balancer shaft. Can be used as a part.

According to the eighth aspect of the present invention, since the balancer weight is fixed with bolts from outside the cylindrical member, the balancer weight can be easily fixed.

According to the ninth aspect of the present invention, the balancer weight, the cylindrical member, and the core member penetrating substantially at the center of the lid member disposed at both ends of the cylindrical member are fixed with bolts, so that the balancer of the rotating balancer shaft is fixed. The weight can be stably held. In addition, the portions protruding to both outsides of the lid member can be used as the rotation axis of the balancer shaft.

[Brief description of the drawings]

FIG. 1 shows a balancer shaft for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 shows a balancer shaft for an internal combustion engine according to a second embodiment of the present invention.

FIG. 4 shows a state in which the balancer shaft for an internal combustion engine according to the first embodiment of the present invention is attached to an engine.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 shows a balancer shaft for an internal combustion engine according to a third embodiment of the present invention.

FIG. 7 shows a pressing step of a balancer shaft for an internal combustion engine according to a third embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view of a pipe member of a balancer shaft for an internal combustion engine according to a third embodiment of the present invention.

FIG. 9 shows a balancer shaft for an internal combustion engine according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view taken along the line CC in FIG. 9;

[Explanation of symbols]

12, 102, 104, 152, 154 ... pipe material (cylindrical material) 20, 30, 26, 36, 106, 108, 110, 1,
56, 158, 160 ... lid (lid material) 24, 124 ... oil introduction groove 34, 126, 128 ... oil discharge groove 40 ... rod (balancer weight) 112 ... pipe 162 ... Core material 172, 174 ... Weight

Claims (9)

[Claims] 1. A balancer shaft for an internal combustion engine comprising: a cylindrical member; a balancer weight eccentrically fixed inside the cylindrical member; and a plurality of lid members closing both ends of the cylindrical member. 2. The balancer shaft for an internal combustion engine according to claim 1, wherein the balancer weight is formed of a bar, and both ends of the bar are held by the lid. 3. An oil introduction hole is provided in one end of the cylindrical member at both ends of the cylindrical member, and an oil discharge hole is provided in the other end of the cylindrical member. 3. The balancer shaft for an internal combustion engine according to 2. 4. The balancer shaft for an internal combustion engine according to claim 1, wherein said balancer weight is formed of a pipe material, and said pipe material is bent and eccentric. 5. The balancer shaft for an internal combustion engine according to claim 4, wherein said pipe member is formed by bending by press working. 6. The balancer shaft for an internal combustion engine according to claim 4, wherein the pipe member is held at a central portion of the lid member. 7. The balancer shaft for an internal combustion engine according to claim 4, wherein said pipe member is an oil passage. 8. The balancer shaft for an internal combustion engine according to claim 1, wherein said balancer weight is fixed with bolts from outside said cylindrical member. 9. The balancer shaft for an internal combustion engine according to claim 8, wherein the bolt integrally fixes the balancer weight, the cylindrical member, and a core member penetrating substantially at the center of the plurality of lid members. .