JPH116428A - Vibration absorbing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration absorbing mechanism capable of high-efficiently damping vibration in any direction of the exhaust route of an internal combustion engine. SOLUTION: A vibration absorbing device 10 comprises a flexible pipe 12; an inner pipe 14; a first cover 16; a second cover 18; a spacer 20; and a coil spring 22. When this vibration absorbing device 10 received vibration in a bending direction, the first cover 16 is vibrated in a bending direction. In this case, the curved surface part 18c of the second cover 18 is slid over a contact surface formed approximately in a semispherical shape of the spacer 20, a relative angle position between the two covers 16 and 18 is changed, the flexible pipe 12 is expanded, contracted, and bent therealong, and the coil spring 22 is expanded and contracted. As a result, bending vibration is high efficiently damped, and hardly transmitted to the second cover 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vibration absorbing mechanism used in an exhaust passage of an internal combustion engine or the like.

[0002]

2. Description of the Related Art Conventionally, as a vibration absorbing mechanism used in an exhaust passage of an internal combustion engine, for example, Japanese Unexamined Patent Publication No.
No. 3 is known.
The vibration absorbing mechanism described in the above publication is shown in FIG.
As shown in the sectional view of FIG. 2 and the view from the upstream side in FIG. 2B, each end of the first cover 66 and the second cover 68 is spot-welded to each end of the bellows 62 which is a flexible pipe. The other ends of 66, 68 are connected via springs 72, 72 provided at two upper and lower locations.

In this vibration absorbing mechanism, for example, when a load is applied in the bending direction, the springs 72 expand and contract and the bellows 62 bends to attenuate and absorb the vibration. As a result, transmission of vibration from the exhaust pipe U on the upstream side to the exhaust pipe L on the downstream side is prevented.

[0004]

However, in the above vibration absorbing mechanism, when the exhaust pipe U on the upstream side vibrates due to the vibration of the engine, the bellows 62 and the spring 7
The expansion and contraction of the bases 2 and 72 absorb the vibration and prevent the transmission of the vibration to the downstream exhaust pipe L.
In some cases, vibrations cannot be sufficiently absorbed only by the expansion and contraction of the springs 2 and the springs 72, 72. In addition, since there is no member for guiding the expansion and contraction operation of the bellows 62 and the springs 72 and 72, there is a possibility that they do not expand and contract smoothly in response to vibration.

Further, in the above vibration absorbing mechanism, FIG.
The bending vibration in the vertical direction in (b) has the largest amplitude at the location where the springs 72, 72 are provided, so that the damping effect due to the expansion and contraction of the springs 72, 72 is high.
The bending vibration in the left-right direction of (b) has a small amplitude at the place where the springs 72, 72 are provided.
The damping efficiency due to expansion and contraction of No. 2 is low. For this reason, there is a problem that the damping efficiency is high for vibration in a specific direction, but low for vibration in another direction.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a vibration absorbing mechanism capable of efficiently damping vibrations in any direction of an exhaust passage of an internal combustion engine.

[0007]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, a vibration absorbing mechanism of the present invention comprises a flexible pipe and a first cover having one end attached to the outer peripheral surface of one end of the flexible pipe. A second cover having one end attached to the outer peripheral surface of the other end of the flexible pipe, and a biasing member that urges the first cover and the second cover so as to approach each other, and surrounds the flexible pipe. One coil spring is pressed and sandwiched between the first cover and the second cover by the urging force of the spring, and a contact surface with the first cover or the second cover is formed in a substantially hemispherical shape. And a spacer.

In the vibration absorbing mechanism of the present invention, when the vibration of the engine is transmitted to, for example, the first cover and the first cover vibrates in the bending direction, the first cover or the second cover is formed in a substantially hemispherical shape of the spacer. Sliding on the formed contact surface,
The relative angular position of the first cover and the second cover changes. Along with that, the flexible pipe expands and contracts,
The spring expands and contracts. When the first cover vibrates in the bending direction in this manner, the flexible pipe expands and contracts and the spring expands and contracts, and the first cover or the second cover slides on the contact surface of the spacer.
The vibration is efficiently absorbed.

Further, since the first cover or the second cover slides while being guided by the contact surface of the spacer which is formed in a substantially hemispherical shape, the relative angular position between the two covers is smaller than that without the guide. Changes smoothly. Therefore, the flexible pipe and the spring also operate smoothly, and the vibration is efficiently absorbed.

Therefore, according to the vibration absorbing mechanism of the present invention,
The effect of effectively attenuating the vibration of the exhaust pipe on the upstream side and effectively preventing the vibration of the exhaust pipe on the upstream side from being transmitted to the exhaust pipe on the downstream side can be obtained. Also,
Since one coil spring is used, the elastic modulus of the spring is the same for bending vibration in any direction,
The effect is obtained that vibration is efficiently absorbed with the same damping efficiency.

In the present invention, as the spacer, for example, a spacer formed of an elastically deformable material or a spacer having a large coefficient of friction can be used. Specifically, the spacer is formed of an elastomer such as rubber. A spacer, a spacer formed of a metal fiber, or the like can be used.
Among them, spacers made of metal fibers are preferable in consideration of heat resistance and the like. Specifically, it is preferable to use a wire mesh or the like. In the present invention, since the spacer is not required to have a sealing property, it is cost-effective to use a wire mesh containing no graphite.

Further, in the present invention, the coil spring may have a substantially constant coil diameter from one end to the other end, and may be provided in a gap between the first cover and the second cover. In this case, the gap between the first cover and the second cover can be made substantially equal to the diameter of the winding of the coil spring, that is, the gap can be minimized. The effect of not being bulky is obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the vibration absorbing device of the present embodiment. The vibration absorbing device 10 of this embodiment includes a flexible pipe 12, an inner pipe 14, a first cover 16, a second cover 18, a spacer 20, and a coil spring 22.

The flexible pipe 12 is a bellows made of metal, and its pipe wall does not allow fluid to pass therethrough. The flexible pipe 12 has an upstream end 12a and a downstream end 12b formed in a straight pipe shape, and a wave-shaped flexible portion in which peaks and valleys are alternately arranged between the both ends 12a and 12b. 1
2c. This flexible pipe 12 can expand and contract in the axial direction and bend in the bending direction because the peaks and valleys of the flexible portion 12c can expand and contract in the width direction (left and right directions in FIG. 1).

The inner pipe 14 is a stepped pipe disposed so as to be coaxial with the flexible pipe 12, and has a small-diameter sleeve 14a and a large-diameter sleeve 14b. Of these, the small-diameter sleeve 14a is arranged with a gap from the flexible pipe 12, and the large-diameter sleeve 14a
b is closely attached and fixed to the inner peripheral surface of the upstream end 12a of the flexible pipe 12. The end of the small diameter sleeve 14a extends to a position short of the downstream end 12b of the flexible pipe 12.

The first cover 16 has an upstream end 16a,
It has an enlarged diameter portion 16b whose diameter is larger than that of the upstream end portion 16a. The upstream end 16a is a flexible pipe 1
2 is fixed to the outer peripheral surface of the upstream end 12a,
b is provided so as to cover the outer periphery of the flexible portion 12c. A first spring receiving portion 17 projecting outward in the radial direction is provided upright on the entire diameter of the enlarged diameter portion 16b. On the downstream surface of the first spring receiving portion 17, bulging portions 17a are provided at predetermined intervals along the circumference.

The second cover 18 has a downstream end 18a,
The enlarged diameter portion 18b which is larger in diameter than the downstream end portion 18a.
And a curved surface portion 18c formed in a substantially hemispherical shape from the downstream end portion 18a to the enlarged diameter portion 18b, and substantially parallel to the enlarged diameter portion 16b of the first cover 16 from the enlarged diameter portion 18b toward the upstream side. And an extending portion 18d having a shape extending as described above. The downstream end 18a of the second cover 18 is fixed to the outer peripheral surface of the downstream end 12b of the flexible pipe 12, and the enlarged diameter portion 18b is provided so as to cover the first spring receiving portion 17 of the first cover 16. ing. Second cover 18
A second spring receiving portion 19 is provided over the entire circumference at the end of the extending portion 18d so as to protrude inward in the radial direction. The tip 19a of the second spring receiving portion 19
Is bent toward the downstream side.

The spacer 20 includes the first spring receiving portion 1.
7 and a curved surface portion 18c of the second cover 18. The contact surface 20c of the spacer 20, which is in contact with the curved surface portion 18c of the second cover 18, is formed in a substantially hemispherical shape, like the curved surface portion 18c. As the spacer 20, it is preferable to use a metal member which is excellent in heat resistance and is durable and capable of absorbing a stretching force, a bending force, and a twisting force. Therefore, a wire mesh is employed here. Also,
Since the spacer 20 does not require a sealing property, an inexpensive wire mesh containing no graphite was used. In the vibration absorbing device 10 of the present embodiment, since the spacer 20 functions as a so-called ball joint, the first cover 16
The relative angular position of the and the second cover 18 can be arbitrarily changed.

The coil spring 22 has a shape wound around the flexible pipe 12. More specifically, the coil spring 22 is moved in the first cover 16 with the enlarged diameter portion 16b of the first cover 16 inserted through the center.
It is arranged between the spring receiving portion 17 and the second spring receiving portion 19, and urges the two spring receiving portions 17, 19 to be separated from each other. That is, the coil spring 22 urges the first cover 16 downstream (to the right in FIG. 1) and the second cover 18 to upstream (to the left in FIG. 1). 16, 18 are biased to approach. Also, this coil spring 22
The coil diameter is substantially constant from one end to the other end, and the enlarged diameter portion 16b of the first cover 16 and the extension portion 18 of the second cover 18
d. This gap is formed to have a size in which some allowance is added to the diameter of the winding of the coil spring 22. In addition, the spacer 20 applies the first force of the first cover 16 to the first cover 16 by the urging force of the coil spring 22.
The bulging portion 17a of the spring receiving portion 17 and the second cover 1
8 is pressed and sandwiched between the curved surface portions 18c.

Next, the operation of the vibration absorbing device 10 according to the present embodiment will be described. In this vibration absorbing device 10, the flexible pipe 12 has a hermeticity and the inner pipe 1
The fourth large-diameter sleeve 14b is in close contact with the flexible pipe 12. The upstream exhaust pipe (not shown) is inserted so as to be inscribed in the large-diameter sleeve 14b, and the downstream exhaust pipe (not shown) is inserted so as to be inscribed in the downstream end 12b of the flexible pipe 12. Therefore, the exhaust gas flowing through the upstream exhaust pipe (not shown) passes through the vibration absorber 10 without leaking to the outside, and is guided to the downstream exhaust pipe (not shown).

When the vibration absorbing device 10 receives vibration in the bending direction, the first cover 16 vibrates in the bending direction. At this time, the curved surface portion 18c of the second cover 18 slides on the substantially hemispherical contact surface 20c of the spacer 20, and
That is, the spacer 20 functions as a so-called ball joint, and the relative angular position of the covers 16 and 18 changes. Then, the flexible pipe 12
Expands and contracts, and the coil spring 22 expands and contracts. As described above, when the vibration absorbing device 10 receives the vibration in the bending direction, the first cover 16 vibrates in the bending direction. This vibration is caused by the flexible pipe 12 expanding and contracting, the coil spring 22 expanding and contracting, and the second cover Curved surface 1 of cover 18
The vibration is efficiently absorbed by the sliding movement of the contact surface 20c of the spacer 20 by the spacer 8c. As a result, almost no vibration is transmitted to the second cover 18.

Further, since the second cover 18 slides while being guided by the contact surface 20c of the spacer 20 which is formed in a substantially hemispherical shape, the relative position between the two covers 16, 18 is smaller than that in the case where there is no guide. The angular position changes smoothly. Therefore, the flexible pipe 12 and the coil spring 22 also operate smoothly, and the vibration is efficiently absorbed.

Further, in the present embodiment, a single coil spring 22 wound around the outer periphery of the enlarged diameter portion 16b of the first cover 16 is used. Therefore, the degree of expansion and contraction of the coil spring 22 is the same for bending vibration in any direction, and bending vibration in any direction is efficiently attenuated and absorbed. Also, since there is no need to install a plurality of springs, the assemblability is excellent, and since there is no need to provide a support member such as a pin in the center hole of the spring, the cost of parts is not increased.

Further, the first cover 16 and the second cover 18
In the conventional example shown in FIG. 2, a gap as large as the coil diameter (that is, the diameter of the winding + the diameter of the center hole + the diameter of the winding) is required. In contrast to the necessity of securing a space, in the present embodiment, a gap as small as the diameter of the winding of the coil spring 22 is sufficient, so that the apparatus configuration can be downsized and a small installation space is required. There is also.

It should be noted that the embodiments of the present invention are not limited to the above-mentioned embodiments at all, and it goes without saying that various forms can be adopted as long as they fall within the technical scope of the present invention.
For example, in the above embodiment, the first spring receiving portion 17 has the bulging portion 17a on the downstream surface, but such a bulging portion 17a may not be provided. In this case, the spacer 2
0 is pressed and clamped by the first spring receiving portion 17 and the curved surface portion 18c of the second cover 18.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vibration absorbing device according to the present embodiment.

FIG. 2 is an explanatory view of a conventional vibration absorbing device;
(A) is sectional drawing, (b) is the figure seen from the upstream.

[Explanation of symbols]

10: vibration absorber, 12: flexible pipe, 14: inner pipe, 16: first cover,
16a: upstream end, 16b: enlarged diameter part, 17
..First spring receiving portions, 17a ... bulging portions, 18
... 2nd cover, 18a ... Downstream end, 18b
..Diameter enlarged portion, 18c ... curved surface portion, 18d ... extended portion, 19 ... second spring receiving portion, 20 ... spacer, 20c ... contact surface, 22 ... coil spring .

Claims (3)

[Claims] A first cover having one end attached to the outer peripheral surface of one end of the flexible pipe; a second cover having one end attached to the outer peripheral surface of the other end of the flexible pipe; One coil spring having a shape surrounding the flexible pipe is urged so as to approach both the one cover and the second cover, and the first cover and the second cover are urged by the spring. And a spacer which is pressed and held between the first cover and the second cover, and has a contact surface with the first cover or the second cover, the spacer having a substantially hemispherical shape. 2. The vibration absorbing mechanism according to claim 1, wherein said spacer is a wire mesh not containing graphite. 3. The coil spring according to claim 1, wherein a coil diameter of the coil spring is substantially constant from one end to the other end, and is provided in a gap between the first cover and the second cover. Vibration absorbing mechanism.