JP3264298B2 - Dual mode muffler negative pressure actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a negative pressure type actuator applied to a dual mode muffler in which exhaust passages having different silencing characteristics are switched by a switching valve via a negative pressure type actuator.

[0002]

2. Description of the Related Art Various types of dual mode mufflers using a negative pressure type actuator and a switching valve have been proposed, one example of which is shown in FIG.

In FIG. 3, a dual mode muffler 1 has a muffler main body 2 in which first, second, third and fourth expansion chambers 6, 7, 7, 8 and 9 are separated by partitions 3, 4, and 5. It is divided into. Inlet pipe 10 is in second expansion chamber 7
The communication pipe 11 communicates between the second expansion chamber 7 and the fourth expansion chamber 9, the resonance pipe 12 communicates between the first expansion chamber 6 and the third expansion chamber 8, Has a plurality of communication holes 1
3, and two outlet pipes 14 and 15 communicate with the first expansion chamber 6. Outside the muffler body 2,
A bypass pipe 16 that communicates between the first expansion chamber 6 and the fourth expansion chamber 9 is provided. In the middle of the bypass pipe 16, an opening / closing operation is performed by a negative pressure actuator 20 according to an operation state of the engine. A switching valve 17 is provided.

The negative pressure type actuator 20 has a negative pressure chamber 23 defined therein by a diaphragm 22 whose outer peripheral portion is sealed and held by a main body 21. Diaphragm 22
Receiving plates 2 on both sides for hermetically holding the inner periphery of
A substantially L-shaped lever 27 is slidably and loosely fitted on the actuator rod 26 fixed to the actuator rods 4, 25, and the compression spring 2 wound around and supported by the actuator rod 26.
8 is always urged so as to contact the lower receiving plate 25. The lower end of the lever 27 is connected to a valve operating lever of the switching valve 17 via a cable 30 or the like. The negative pressure chamber 23 is connected to an outlet of a control valve 32 such as a three-way solenoid valve through a passage 31, and one inlet of the control valve 32 is connected to an intake manifold of the engine through a negative pressure passage 33. The other inlet is connected to the atmosphere via an atmosphere opening passage 34. The control valve 32 is switched by an electronic control unit 35 to which information indicating the operating state of the engine such as the engine speed and the throttle opening is input.

In the operation of the dual mode muffler 1, the electronic control unit 3 is operated at a low engine speed.
5 switches the control valve 32 so that the negative pressure chamber 23 of the negative pressure actuator 20 communicates with the negative pressure passage 33.
The diaphragm 22 and the actuator rod 26 are pushed upward from a lower position in the drawing by the differential pressure between the manifold negative pressure in the negative pressure chamber 23 and the atmosphere, and the lever 27 is also moved upward via the compression spring 28. The movement of the lever 27 is transmitted to the valve operating lever of the switching valve 17 via the cable 30, and the switching valve 17 is operated to close, thereby closing the bypass pipe 16. As a result, the exhaust gas from the engine exhaust manifold, as indicated by the black arrow in FIG.
Inlet pipe 10, second expansion chamber 7, communication hole 13 of partition 4,
The air is discharged from the outlet pipes 14 and 15 into the atmosphere via the third expansion chamber 8, the resonance pipe 12, and the first expansion chamber 6. The first exhaust passage including the inlet pipe 10, the second expansion chamber 7, the third expansion chamber 8, the resonance pipe 12, the first expansion chamber 6, and the outlet pipes 14 and 15 reduces exhaust gas discharge noise. It has a noise reduction characteristic that minimizes the muffled sound in the room.

In the middle and high rotational speed range of the engine, the electronic control unit 35 controls the control valve 3 so that the negative pressure chamber 23 of the negative pressure type actuator 20 communicates with the atmosphere opening passage 34.
2 is switched. When the atmosphere communicates with the negative pressure chamber 23, the differential pressure across the diaphragm 22 disappears, the force for holding the diaphragm 22 and the lever 27 at the upper position in the drawing disappears, and the switching valve 17 is opened by the force of the spring, thereby bypassing. Open tube 16. As a result, as shown by a white arrow in FIG.
The outlet pipe 1 passes through the second expansion chamber 7, the communication pipe 11, the fourth expansion chamber 9, the open bypass pipe 16 and the first expansion chamber 6.
It is discharged into the atmosphere from 4,15. These inlet pipes 1
0, second expansion chamber 7, communication pipe 11, fourth expansion chamber 9, bypass pipe 16, first expansion chamber 6, and outlet pipes 14, 15
The second exhaust passage has a noise reduction characteristic that reduces exhaust resistance and improves engine performance and minimizes airflow noise that increases with an increase in the flow rate of exhaust gas.

[0007]

The conventional dual mode muffler negative pressure actuator 20 described above has the following problems to be solved. (1) The negative pressure type actuator 20 is provided with a stopper rubber 36 which comes into contact with the inner upper surface 21a of the main body 21 in order to determine the operation limit of the receiving plate 24 and the like lifted by the application of the negative pressure. However, the conventional stopper rubber 36 has a hardness of about 70 Hs (Shore hardness), has a flat contact portion at the tip, and has not been subjected to any special treatment. In some cases, it may be in close contact with 21a like a suction cup. When the operation mode of the engine is changed from the close contact state and the exhaust mode of the dual mode muffler 1 is switched, the moment the atmospheric pressure is introduced into the negative pressure type actuator 20, the stopper rubber 3
There was a problem that the close contact of No. 6 was peeled off and an operation sound (so-called paco noise) was generated. This operating sound turns off the engine key.
In particular, the evaluation is also bad because the same occurs when the setting is made. (2) Since the high-stroke type negative pressure actuator 20 is employed, the upper portion of the diaphragm 22, which is not restricted by the receiving plate 24 when negative pressure is applied, bulges inward as shown by the broken line in FIG. Since no base cloth is used, 8 to 10 wrinkles 37 are generated (see FIG. 5). For this reason, as the number of operations increases, cracks may occur in the wrinkles, which may cause airtight leaks, and there is a concern about durability.

Accordingly, an object of the present invention is to improve the stopper rubber to prevent the generation of operation noise, and to improve the shape of the receiving plate to prevent the diaphragm from wrinkling when a negative pressure is applied. And

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a negative pressure type dual mode muffler for opening and closing switching valves provided in a plurality of exhaust pipes having different noise reduction characteristics. In the actuator, a diaphragm forming a negative pressure chamber in the main body, a receiving plate fixed to the diaphragm and connected to the actuator rod, and a matte surface fixed to the receiving plate
A dual mode muffler negative pressure actuator, comprising: a stopper rubber having a projection .

Further, the negative plate type actuator of the dual mode muffler, wherein the receiving plate has a wall extending in the axial direction of the actuator rod along the surface of the diaphragm.

[0011]

According to the above-mentioned means, a protrusion having a satin-like surface is provided.
Since the stopper rubber is used, it is possible to prevent the stopper rubber from being in close contact with the inner upper surface of the main body due to the application of the negative pressure.

Also, the shape of the receiving plate is changed,
By providing the wall portion extending in the axial direction of the actuator rod along the surface of the diaphragm , it is possible to prevent the diaphragm from expanding inward when a negative pressure is applied.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a dual mode muffler negative pressure type actuator according to the present invention will be described with reference to FIGS.

The negative pressure type actuator 4 shown in FIG.
0 denotes a main body 41, a diaphragm 42, a negative pressure chamber 43, receive plates 44 and 45, an actuator rod 46,
Lever 47, compression spring 48 and stopper rubber 49
It is comprised including. Of these, the stopper rubber 49 that contacts the inner upper surface 41a of the main body 41 is shown in FIG.
As shown in the figure, a semicircular projection 49a is provided on the contact surface, and the surface is subjected to satin finish. Further, a rubber of about 80 Hs, which is harder than the conventional rubber, is used for the stopper rubber 49. However, if the hardness is higher than that, a hitting sound at the time of abutment becomes a problem, which is not suitable.

The receiving plate 44 is provided with a wall 44a extending in the axial direction of the actuator rod 46 along the surface of the diaphragm 42. This wall 4
The height h of 4a (see FIG. 2B) is, for example, a long stroke type having a stroke amount of 45 mm in FIG.
From the experimental result of (A), the film thickness of the diaphragm 42 is set to 0.
If it is 6 mm, about 15 mm is optimal. That is,
Under such conditions, the wrinkle depth a becomes 0 (no wrinkles), and the number of operations until the diaphragm breaks is about 4 times.
× 10 Increases up to ⁶ times. In addition, such a wall part 44a
In order to prevent the upper end of the receiving plate when negative pressure is applied from interfering with the inner upper surface 41a of the main body 41, a ring-shaped relief portion 41b is provided on the upper surface of the main body 41.

With the negative pressure actuator having the above-described configuration, the diaphragm 42,
When the receiving plates 44 and 45, the actuator rod 46, and the like are lifted, the projection 49a of the stopper rubber 49 abuts on the inner upper surface 41a, and defines one stroke limit of the negative pressure type actuator rod 46. At this time, the protruding portion 49a is pressed against the inner upper surface 41a, but does not adhere to the inner upper surface 41a because of its shape and the effect of the matte surface, as well as high hardness. For this reason,
When the atmospheric pressure is introduced into the negative pressure chamber 43 by switching the exhaust mode and the pressing force of the projection 49a is released, the projection 4
9a can be smoothly separated from the inner upper surface 41a, and the operation noise which has conventionally been a problem is not generated.

When the negative pressure is applied, the wall portion 44a of the receiving plate 44 prevents the diaphragm 42 from bulging inward, so that wrinkles are not generated and cracks are less likely to enter the diaphragm. Therefore, the durability of the negative pressure type actuator 40 is significantly improved, and the exhaust mode switching operation of the dual mode muffler becomes highly reliable.

[0018]

According to the present invention described above, the operating noise (paco noise) of the negative pressure type actuator generated at the time of switching the exhaust mode is eliminated, and the durability of the negative pressure type actuator is improved, so that the reliability is improved. It has a great effect on providing dual mode mufflers that are excellent in terms of marketability and merchantability.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a negative pressure type actuator of a dual mode muffler according to the present invention, wherein FIG. 1 (A) is a sectional view of a main part, and FIG. 1 (B) is a view showing an example of a shape of a stopper rubber of FIG. .

FIGS. 2A and 2B show experimental results relating to durability of a negative pressure type actuator, in which FIG. 2A is a graph showing the relationship between the number of actuations until the diaphragm breaks and the wall height h, and FIG. It is a model figure which shows height a and wall height h.

FIG. 3 is a system diagram showing an example of a dual mode muffler.

FIG. 4 is a diagram showing a state where the diaphragm bulges inward when a negative pressure is applied.

FIG. 5 is a diagram showing an example of wrinkles occurring in the diaphragm of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dual mode muffler 20, 40 Negative pressure type actuator 21, 41 Main body 22, 42 Diaphragm 23, 43 Negative pressure chamber 24, 25, 44, 45 Receive plate 26, 46 Actuator rod 36, 49 Stopper rubber 44a Wall part 49a Projection part

──────────────────────────────────────────────────続 き Continued on the front page (72) Keigo Ogawa, Inventor 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Tatsuro Nakajima 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (56) References Japanese Utility Model sho 59-180003 (JP, U) Japanese Utility Model sho 57-120712 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01N 7/08

Claims (2)

(57) [Claims] A negative pressure type actuator of a dual mode muffler for opening and closing a switching valve provided in a plurality of exhaust pipes having different muffling characteristics, a diaphragm forming a negative pressure chamber in a main body, and an actuator fixed to the diaphragm. A negative pressure actuator for a dual mode muffler, comprising: a receiving plate connected to a rod; and stopper rubber fixed to the receiving plate and having a projection on a matte surface . 2. The dual-mode muffler negative pressure actuator according to claim 1, wherein said receiving plate has a wall extending along an axial direction of said actuator rod along a surface of said diaphragm.