JPH112290A - Balance shaft device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balance shaft device provided with a damper device having excellent workability. SOLUTION: A damper device 30 is located between the first gear 11 of a first shaft 10 and a drive gear 12. The damper device comprises a first spring holder 31 which is fixed at the first gear and at which four first spring stoppers are fixed; a second spring holders 35 to fix four second spring stopper approximately in the same position; a ring holder 41 to hold the two members 31 and 35: and four springs 43. When the first and second spring holders are concentrically rotated relatively, the first and second spring stoppers are arranged in a manner to prevent the occurrence of mutual interference to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance shaft device connected to a crankshaft via a gear.

[0002]

2. Description of the Related Art An inertia force is generated in a reciprocating portion of an engine such as a piston and a connecting rod, and an inertia force and an inertia couple are generated in a multi-cylinder engine. Therefore, a balance shaft is used to cancel these forces. ing. When the balance shaft is connected to the crank gear via a gear, gear noise is generated in the meshing gear due to torque fluctuation of the crank gear.

[0003] In order to absorb the above-mentioned torque fluctuation of the crank gear, there is a type in which a shock absorbing damper device is provided in a gear portion of a shaft. That is, as shown in FIG.
The balance shaft device 90 includes a first balance shaft 91 driven by a crank gear 85, and a second balance shaft 92 driven by the first balance shaft 91.
And

As shown in FIGS. 12 and 13, the first balance shaft 91 includes a first gear 911 meshing with the crank gear 85 and a second gear 912 (FIG. 13) meshing with the second balance shaft 92. As shown in FIG. 12, the second balance shaft 92 has the second gear 91
And a third gear 921 that meshes with the second gear 921.

In FIG. 12, reference numeral 86 denotes a connecting rod,
Reference numeral 871 denotes a front lower case of the cylinder head, and reference numeral 8 denotes a lower case.
Reference numeral 72 denotes a rear lower case of the cylinder head, and the balance shaft device 90 includes the lower cases 871, 872
It is installed in the narrow space between FIG.
In the figure, reference numeral 913 denotes an eccentric shaft whose center of gravity is eccentric with respect to the axis, and reference numerals 914 and 915 denote bearing portions.

[0006] As shown in FIG. 13, a crank gear 8 is provided between the second gear 912 and the first gear 911.
Absorb torque fluctuation of 5 to suppress gear noise,
A damper device 93 for buffering is provided. As shown in FIG. 14, the damper device 93 includes an annular first spring holding member 931 fixed to the first gear 911 via a pin 915, a second spring holding member 933 fixed to the second gear 912, and And both spring holding members 9
Four springs 935 and a spring contact member 937 are disposed between 31, 933.

The spring holding members 931 and 93
3 includes springs 93 at substantially the same angular position in the rotational direction.
A pair of projecting pieces 932 and 934 for making the abutment 5 contact each other is formed. The spring contact member 937 is an arc-shaped plate having a vertical U-shape in cross section with respect to the arc-shaped cross-section line, and the long side 941 of the U-shape is formed on the first gear 911 side or the second gear side. On the 912 side, they are alternately arranged between a pair of projecting pieces 932 and 934.

The spring contact member 937 has one of the short sides 943 and 944 of the U-shape projecting pieces 933 and 92.
4 and the other short sides 945 and 946 are positioned inside the U-shape of the other party. The spring 935 is disposed between the one short side portion 943 or 944 of the one spring contact member 937 and the other short side portion 946 or 945 of the other spring contact member 937. The length H of the short sides 943 to 946 is equal to the protrusion width h of the spring holding members 931 and 933.
1 and h2.

When the first gear 911 rotates as shown by the arrow in FIG. 14, the projecting piece 932 of the first spring holding member 931 moves to the short side 94 of the first spring contact member 937.
3, and further presses the second spring contact member 937 via the spring 935. As a result, the short side portion 944 of the second spring contact member 937 presses the protruding piece 934 of the second spring holding member 933 to rotate the second spring holding member 933 (second gear 912).

As described above, the first gear 911 drives the rotation of the second gear 912 via the spring 935, and the spring 935 buffers the crank gear 85.
And suppress the occurrence of gear noise.

[0011]

However, the above-mentioned conventional damper device 93 has a problem that the workability of assembling is poor as described below. That is, the above assembly is
First, the spring 9 is attached to the second spring holding member 933.
Then, the first gear 911 is fixed to the first spring holding member 931 by mounting the first spring holding member 931 on the spring 935 and the spring contact member 937.

However, the second spring holding member 9
33, a spring 935 and a spring contact member 937
The work of attaching the requires skill and is difficult. That is, the work is performed while strongly pressing and narrowing the spring 935 while resisting the urging force of the spring 935.
And the spring contact member 937 must be fitted between the protruding pieces 932 and 934, and workability is not good.

At this time, since the spring 935 is a straight coil spring in a natural state, it must be mounted while being bent in an arc shape, and a force for moving the spring contact member 937 is likely to work. On the other hand, if the spring abutment member 937 is not correctly oriented in a predetermined direction in the horizontal and vertical directions, the springs 935 will cause the two to bend in a horizontal or vertical U-shape due to the urging force of the spring 935, and the protruding pieces 931. Mounting between 934 fails. As can be seen from the above, the assembling work of the damper device is not easy.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a balance shaft device having a damper device with good assembling workability.

[0015]

The present invention relates to a balance shaft device that rotates while meshing with a crank gear of an engine, comprising: a first balance shaft having a first gear meshing with the crank gear; And a second balance shaft provided with a third gear meshing with the second gear of the first balance shaft. Between the first gear and the second gear of the first balance shaft, a buffer for absorbing torque fluctuation of the crank gear is provided. A first spring holder fixed to the first gear and having four first spring stoppers rotationally symmetrically arranged on an outer peripheral portion thereof; and 2 gears and four second springs at substantially the same position as the first spring stopper.
A second spring holder in which the spring stoppers are arranged in a rotationally symmetric manner, a ring holder for holding both members inside so that the first and second spring holders can rotate concentrically with each other, and a second spring holder adjacent to each other. A first spring and a first spring holder, the first gear and the first spring holder having four springs disposed between the first and second spring stoppers and having both ends abutting against the end surface of the spring stopper and urged to expand; And between the second gear and the second spring holder are fixed by pressing a pin projecting from the spring holder or the gear into a pin hole formed in the gear or the spring holder. Characteristic balance shaft device.

The most remarkable point in the present invention is that
A spring holder having a plurality of spring stoppers arranged in rotational symmetry is fixed to the first gear and the second gear, respectively (see FIGS. 3, 5 to 8), and the first spring stopper (FIG. 5). , FIG. 6, reference numeral 32) and the second spring stopper (FIGS. 7, 8, reference numeral 36) are arranged at substantially the same rotational position, and the first spring holder and the second spring holder are concentric. The first spring stopper and the second spring stopper do not interfere with each other when they are relatively rotated (see FIGS. 6 and 8). And the first and second spring holders are held inside the ring holder,
Springs whose end faces are in contact with the spring stoppers are arranged between the spring stoppers adjacent to each other (see FIGS. 10 and 11).

With the above structure, assembling of the damper device does not become difficult as in the conventional device shown in FIG. In other words, it is possible to assemble the damper device by fitting both spring holders inside the ring holder and then fitting the springs between the four spring stoppers while pressing and narrowing the springs against the biasing force. it can.

At this time, the spring stopper is fixed to the spring holder, and the spring holder is fitted in the ring holder. Therefore, when the spring is mounted, the spring contact member 93 of the conventional device is used.
7, the spring stopper itself does not fluctuate or move. Therefore, mounting of the spring, which has been a factor of difficulty in assembling in the conventional device, becomes extremely easy.

Then, a pin protruding from the spring holder or the gear is pressed into a pin hole formed in the gear or the spring holder to fix the spring holder to the first gear or the second gear. Before assembling the spring holder and the spring, one spring holder may be assembled to the second gear or the first gear.

When the first spring holder and the second spring holder are relatively concentrically rotated, the first spring stopper and the second spring stopper do not interfere with each other. As a configuration, for example, there is a configuration as described in claim 2. That is, each of the first spring stopper and the second spring stopper is provided with a projection for spring contact in a direction parallel to the axis from the fixed gear side to the opposite gear side. The projecting pieces of the stopper and the projecting pieces of the other spring stopper are arranged alternately in the radial direction so as not to abut each other.

As a result, for example, as shown in FIGS.
361, 362) are alternately arranged in the radial direction so as not to contact each other, so that when the first spring holder and the second spring holder are concentrically rotated, the first spring stopper and the second spring stopper are rotated. The spring stopper does not collide with each other.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment This embodiment is, as shown in FIGS. 1 and 2, a balance shaft device 1 that rotates while meshing with a crank gear 85 of an engine crankshaft. A first balance shaft 10 provided;
A second balance shaft 20 having a third gear 21 that meshes with the second gear 12 of the first balance shaft 10.

As shown in FIG. 4, between the first gear 11 and the second gear 12 of the first balance shaft 10, a damper device 30 for absorbing a torque fluctuation of the crank gear 85 is provided. It is interposed. In FIG.
Reference numeral 15 denotes a weight body which integrally forms the second gear 12 and has a center of gravity eccentric from the axis, and reference numeral 19 denotes a shaft.

As shown in FIG. 3, the damper device 30 has four first spring stoppers 32 (FIGS. 5 and 6) fixed to the first gear 11 and rotationally symmetrically arranged on the outer periphery. The first spring holder 31 (FIGS. 5 and 6) and four second spring stoppers 36 (FIGS. 7 and 8) fixed to the second gear 12 and at substantially the same position as the first spring stopper 32. The second members 31 and 35 are positioned inside such that the second spring holder 35 (FIGS. 7 and 8) and the first and second spring holders 31 and 35 can rotate concentrically with each other. An annular ring holder 41 (FIG. 9) for holding and first and second spring stoppers 32, 36 adjacent to each other as shown in FIG.
Between the end faces 3 of the stoppers 32 and 36
25 (FIG. 6), 365, 366 (FIG. 8) and four springs 43 urged to expand.

As will be described below, when the first spring holder 31 and the second spring holder 35 are relatively concentrically rotated, the first spring stopper 32 and the second spring stopper 35 , Are arranged so as not to interfere with each other.

That is, as shown in FIGS. 5 and 7, the first spring stopper 32 and the second spring stopper 36 are moved from the fixed gear 11 or 12 side to the opposite gear 12 or 11 side. The projections 321, 361, and 362 for abutment of the spring 43 are provided in the direction parallel to the shaft center, and as shown in FIGS. 6 and 8, the projection 321 of one spring stopper 32 and the other spring stopper are provided. The 36 projecting pieces 361 and 362 are alternately arranged in the radial direction so as not to come into contact with each other.

First gear 11 and first spring holder 3
3, and between the second gear 12 and the second spring holder 35, pins 47 and 48 protruding from the spring holders 31 and 35 are connected to the first gear 11 as shown in FIG.
Or a pin hole 471 or 48 drilled in the second gear 12
It is fixed by press fitting into 1.

The following is a supplementary explanation for each.
As shown in FIGS. 1 and 2, the balance shaft device 1
First balance shaft 1 driven by crank gear 85
0, and a second balance shaft 20 driven by the first balance shaft 10.

As shown in FIGS. 1 and 4, the first balance shaft 10 includes a shaft 19, a first gear 11 meshing with a crank gear 85, and a weight body 15 eccentric with respect to the axis. A second gear 12 having a gear 121 that meshes with the second balance shaft 20;
A ring-shaped cover 45 covering the weight body 15
(Omitted in FIG. 4). The first gear 11 includes a synthetic resin gear 111 containing a reinforcing material and a metal body 112 such as steel (FIG. 3). And shaft 1
9 and the second gear 12 are made of metal such as steel.

The second balance shaft 20 is shown in FIG.
As shown in FIG. 3, a third gear 21 including a shaft 29, a weight body 23 eccentric with respect to the axis, and a gear 211 meshing with the second gear 12, and a ring-shaped gear covering the weight body 23. And a cover 25. The shaft 29 and the third gear 21 are made of metal such as steel.

As shown in FIG. 3, the weight bodies 15, 23 are composed of thick portions 151, 231 having a semilunar shape, and thin portions 152, 232. The covers 45 and 25 are shown in FIG.
As shown in the figure, the outer peripheral portions 451 and 251 have ring-shaped outer peripheral portions 451 and 251 and approximately half of the outer peripheral portions 451 and 251 come into contact with and cover the outer periphery of the half-moon thick portions 151 and 231 of the weight bodies 15 and 23. ing.

In the vacant portions (thick portions) of the weight bodies 15 and 23 formed by the thin portions 152 and 232, the covers 45 and 25 are provided with a plurality of walls 461 to 463 to form a plurality of recesses 471 to 463. 474 are formed.
The covers 45 and 25 are made of a resin or the like containing a reinforcing material.

In FIGS. 1 and 2, reference numeral 86 denotes a connecting rod, reference numeral 871 denotes a front lower case of the cylinder head, reference numeral 872 denotes a rear lower case of the cylinder head, and reference numeral 873 holds the balance shafts 10 and 20 rotatably. Washer thrust. As shown in FIG. 2, the balance shafts 10, 20 are provided with lower cases 871, 87.
It is mounted in a narrow space between the two. Also, FIG.
, Reference numerals 491 and 492 indicate weight body 1
Bolts fixing the shafts 5, 23 and the shafts 19, 29 are provided. In FIG. 3, reference numeral 115 denotes a snap ring.

As shown in FIGS. 1 and 3, a crank gear 85 is provided between the second gear 12 and the first gear 911.
A damper device 30 for buffering is provided to absorb the torque fluctuation and suppress the generation of gear noise. As shown in FIG. 3A, the damper device 93 includes a disc-shaped first spring holder 31 (FIGS. 5 and 6) for pressing the pin 47 into the pin hole 471 and fixing the pin 47 to the first gear 11. Pin 4
8 is pressed into the pin hole 481 and fixed to the second gear 12 in the form of a disk-shaped second spring holder 35 (FIGS. 7 and 8).
An annular ring holder 41 (FIG. 9) holding both members 31, 35 inside is provided. As shown in FIGS. 10 and 11, four springs 43 are provided between both spring holders 31, 35. It is arranged.

As shown in FIGS. 5 to 8, four spring stoppers 32 and 36 for bringing the spring 43 into contact with the spring holders 31 and 35 are provided at substantially the same angle in the rotational direction as shown in FIGS. It is protruding. The second spring stopper 36 includes two projecting pieces 361 and 362 formed with a space therebetween, and the first spring stopper 32 includes a projecting piece 321 located between the two projecting pieces 361 and 362. Become. Spring holder 31, 35
Consists of steel.

As shown in FIGS. 10 and 11, a spring 43 is provided between the adjacent spring stoppers 32 and 36. FIG. 10 shows a case where there is no positional displacement in the circumferential direction between the first spring stopper 32 and the second spring stopper 36, and FIG. 11 shows a case where there is no displacement between the first spring stopper 32 and the second spring stopper 36. The case where the displacement in the circumferential direction is maximum is shown.

When the torque of the crank gear 85 fluctuates, the first action of the spring 43 is performed by the buffer action of the spring 43.
Spring stopper 32 and second spring stopper 36
The positional deviation in the circumferential direction between FIG. 10 and FIG. 11 fluctuates between FIG. 10 and FIG. 11, so that the shafts 10 and 20 do not have uneven rotation.

That is, the first balance shaft 10 is
0, when rotated as shown by the arrow in FIG. 11, the spring stopper 32 (projection piece 321) of the first spring holder 31
Presses and retracts the spring 43, and presses the spring stopper 36 (projections 361, 362) of the second spring holder 35 via the spring 43 (FIG. 11).
When the torque of the crank gear 85 decreases, the spring 43 expands, and the circumferential displacement between the first spring stopper 32 and the second spring stopper 36 decreases, and the torque of the second gear 12 decreases. Suppress fluctuations and uneven rotation. As a result, rotation unevenness does not occur on the shafts 10 and 20, and generation of gear noise is suppressed.

Further, due to the above-described structure, the assembling work of the damper device 30 is very simple as compared with the conventional device shown in FIG. That is, the spring holders 31 and 35 shown in FIGS. 6 and 8 are fitted inside the ring holder 41 shown in FIG. 9, and then the spring 43 is pressed and narrowed against the urging force.
The damper device 30 can be assembled by fitting the springs 43 between the members 2 and 36, respectively. In FIG. 9, reference numeral 411 is an arc-shaped depression with which the spring 43 contacts.

At this time, the spring stoppers 32, 36
Is the spring holder 3 as shown in FIGS.
1, 35 and a spring holder 3
1 and 35 are fitted in the ring holder 41, so that when the spring 43 is mounted, the spring stopper 3 like the spring contact member 937 of the conventional device is used.
2,36 itself does not fluctuate or move.
Therefore, the mounting work of the spring 43, which was difficult to assemble with the conventional device, becomes extremely easy.

Next, the pin 47 or 48 is inserted into the pin hole 47.
1 or 481 to fix the spring holder 31 or 35 to the first gear 11 or the second gear 12.
Before assembling the spring holders 31, 35 and the spring 43 in the ring holder 41, one of the spring holders 35, 31 may be assembled to the second gear 12 or the first gear 11. as mentioned above,
According to this example, the damper device 3 having good assembling workability is provided.
0 can be obtained.

[0042]

According to the present invention, it is possible to obtain a balance shaft device provided with a damper device having good assembling workability.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of a balance shaft device according to an embodiment.

FIG. 2 is a front view showing the manner of engagement of the balance shaft device of the embodiment with a crank gear.

FIGS. 3A and 3B are a cross-sectional view of the balance shaft device according to the embodiment without the shaft, and a bottom view of FIG.

FIG. 4 is a perspective view showing a first balance shaft of the balance shaft device according to the embodiment with a cover removed.

FIG. 5 is a cross-sectional view of the first spring holder of the first balance shaft according to the embodiment (a cross-sectional view taken along line X1-X1 in FIG. 6);

FIG. 6 is a top view of the first spring holder of FIG. 5;

FIG. 7 is a cross-sectional view of a second spring holder of the first balance shaft according to the embodiment (a cross-sectional view taken along line X2-X2 in FIG. 8);

FIG. 8 is a top view of the second spring holder of FIG. 7;

FIG. 9 is a plan sectional view of the ring holder of the first balance shaft of the embodiment.

FIG. 10 is an enlarged view of the balance shaft portion shown in FIG. 2 and a cross section taken along line Y1-Y1 in FIG. 3 to show a spring (part 1).

FIG. 11 is an enlarged view of the balance shaft portion shown in FIG. 2 and a cross section taken along a line Y1-Y1 in FIG. 3 to show a spring (part 2).

FIG. 12 is a front view showing a state of engagement with a crank gear of a conventional balance shaft device.

FIG. 13 is a perspective view of a first balance shaft of a conventional balance shaft device.

FIG. 14 is an exploded perspective view of a damper device of a conventional balance shaft device.

[Explanation of symbols]

 10. . . First balance shaft 11. . . 1st gear, 12 . . Second gear, 30. . . Damper device, 31, 35. . . Spring holder, 41. . . Ring holder, 43. . . spring,

Claims (2)

[Claims] 1. A balance shaft device that rotates by meshing with a crank gear of an engine, comprising: a first balance shaft having a first gear meshing with the crank gear;
A second balance shaft provided with a third gear meshing with a second gear of the first balance shaft;
Between the first gear and the second gear of the balance shaft, a damper device for absorbing a torque fluctuation of the crank gear is provided, and the damper device is fixed to the first gear and Four first symmetrical outer peripheral parts
And a second spring holder fixed to the second gear and having four second spring stoppers arranged at substantially the same position as the first spring stopper in a rotationally symmetric manner. A ring holder for holding the two members inside so that the first and second spring holders can rotate concentrically with each other, and a first and a second spring stopper which are disposed adjacent to each other and have opposite ends. The first spring holder and the second spring holder are concentrically rotated relative to each other, the four springs being in contact with the end surface of the spring stopper and being urged to expand. In addition, the first spring stopper and the second spring stopper are arranged so as not to interfere with each other. Between the first spring holder,
And a balance between the second gear and the second spring holder, wherein a pin protruding from the spring holder or the gear is fixed by press-fitting into a pin hole formed in the gear or the spring holder. Shaft device. 2. The first spring stopper and the second spring stopper according to claim 1, wherein the first spring stopper and the second spring stopper project from a fixed gear side toward an opposite gear side in a direction parallel to the axis. A balance shaft device comprising a piece, and a projection of one spring stopper and a projection of the other spring stopper are alternately arranged in a radial direction so as not to abut each other.