JP4037571B2 - Pressure switching valve device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure switching valve device that opens and closes in response to exhaust pressure.
[0002]
[Prior art]
As shown in JP-A-10-227208, WO95 / 13460, or FIG. 5, a muffler pipe such as an inlet pipe 3 or a communication pipe is recently used as a pressure opening / closing valve device 1 that changes an exhaust gas flow path in response to an exhaust pressure. There is known a vehicle muffler 5 that is mounted on the vehicle to reduce exhaust noise from a low engine speed range to a high engine speed range without increasing exhaust pressure loss.
[0003]
6 is a front view of a conventional pressure switching valve device 1, FIG. 7 is a sectional view taken along line VII-VII in FIG. 6, and 7 is an insertion side tip (exhaust gas flow downstream side opening end) 3a of the inlet pipe 3 in FIG. As shown in FIG. 6, a pair of flanges 11 are similarly formed on one end side of the valve seat 7 along a pair of flanges 9 provided on one end side of the opening / closing valve 8. Are arranged opposite to each other, and an opening / closing valve 8 is swingably attached to a shaft 13 that passes through the flanges 9 and 11.
[0004]
A coil spring 15 that presses and urges the opening / closing valve 8 is inserted into the valve seat 7 that is enlarged in a trumpet shape on the shaft 13, and one end 15 a of the coil spring 15 contacts the opening / closing valve 8. The other end 15 b is locked to a notch 17 provided in the valve seat 7. The on-off valve 8 is pressed against the valve seat 7 by the spring force of the coil spring 15 in the low rotation range of the engine, and closes the insertion-side tip 3a of the inlet pipe 3.
[0005]
Further, as shown in FIG. 5, the peripheral wall of the inlet pipe 3 is provided with a plurality of small holes 27 that open into the expansion chamber 25 defined in the shell 23 by two baffle plates 19 and 21. The aperture ratio of the small hole 27 is set so that the pressure of the inlet pipe 3 rises from the first volume chamber 29 as the engine speed increases. When the engine shifts to a high rotation range and the pressure difference between the expansion chamber 25 and the first volume chamber 29 rises above a predetermined value, the opening / closing valve 8 resists the spring force of the coil spring 15 and the inlet pipe 3. The insertion-side tip 3a is opened.
[0006]
[Problems to be solved by the invention]
Thus, in the conventional pressure switching valve device 1, the switching valve 8 closes the insertion-side tip 3 a of the inlet pipe 3 by the spring force of the coil spring 15 in the low rotation range of the engine where the internal pressure of the muffler 5 is low, and When the engine shifts to a high rotation range and the internal pressure of the muffler 5 increases, the open / close valve 8 is configured to open the insertion-side tip 3a of the inlet pipe 3 against the spring force of the coil spring 15. As shown in FIG. 8, the reaction force (restoring force) of the coil spring 15 has a property of increasing linearly with increasing strain.
[0007]
For this reason, when the internal pressure of the muffler 5 and the reaction force of the coil spring 15 are balanced at the opening / closing point of the opening / closing valve 8, the opening / closing valve 8 opens when the internal pressure rises, and the opening / closing valve decreases simultaneously with opening. If the valve 8 is closed, and the open / close valve 8 is closed, the internal pressure rises and the open / close valve 8 is opened, so that the open / close valve 8 repeatedly opens and closes, so-called chattering may occur, which may cause noise. Was pointed out.
[0008]
The present invention has been devised in view of such circumstances, and an object of the present invention is to provide a pressure switching valve device that improves the pressure switching valve device as described above and prevents chattering.
[0009]
[Means for Solving the Problems]
In order to achieve such an object, an invention according to claim 1 is a pressure on-off valve device provided with an on-off valve that swingably attaches to a muffler pipe of a vehicle muffler and opens and closes the muffler pipe in response to exhaust pressure. The opening / closing valve closes the muffler pipe with the spring force of the coil spring and the leaf spring having a circular arc section, opens the muffler pipe against the spring force of the coil spring and the leaf spring, and opens the opening / closing valve when the opening / closing valve is opened. The leaf spring is bent to reduce the reaction force.
[0010]
The invention according to claim 2 is the pressure switching valve device according to claim 1, wherein the pressure switching valve device.
The on-off valve is swingably attached to a valve seat attached to the exhaust gas downstream side opening end of the muffler pipe via a shaft, one end of which contacts the on-off valve and the other end contacts or engages the valve seat. A stopped coil spring is inserted, and a leaf spring is installed between the valve seat and the open / close valve so as to be bent in accordance with the opening operation of the open / close valve by a predetermined amount. .
[0011]
(Function)
According to the invention according to each claim, the open / close valve opens and closes the muffler pipe in response to the exhaust pressure, and the open / close valve closes the muffler pipe by the coil spring and the plate spring having an arcuate section, and the coil spring and the plate spring The open / close valve opens the muffler pipe against the spring force of the valve, but when the open / close valve is opened, the leaf spring bends and the reaction force decreases, so the open open / close valve opens the muffler pipe more slowly than before. It will be blocked.
[0012]
Then, the opening / closing valve again closes the muffler pipe by the coil spring and the leaf spring, and thereafter, the opening / closing valve repeats the same operation.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
Since the configuration excluding the invention portion is the same as that of the conventional example shown in FIG. 5 and the subsequent figures, the same components are denoted by the same reference numerals and the description thereof is omitted.
FIGS. 1 to 4 show an embodiment of a pressure switching valve device according to claims 1 and 2, in which 7-1 is a cylindrical shape fixed to the outer periphery of the insertion side tip 3a of the inlet pipe 3. In the valve seat, as shown in FIG. 1, a pair of flanges 11 are similarly arranged on one end side of the valve seat 7-1 along a pair of flanges 9 provided on one end side of the on-off valve 8. An open / close valve 8 is swingably attached via a shaft 13 that passes through the flanges 9 and 11.
[0015]
A coil spring 15-1 that presses and urges the opening / closing valve 8 is inserted into the shaft 13 on the valve seat 7-1 that is enlarged in a trumpet shape on the shaft 13, and like the coil spring 15, the coil spring 15- 1 has one end 15a-1 in contact with the on-off valve 8 and the other end 15b-1 locked to a notch 17 provided in the valve seat 7-1.
Further, as shown in FIGS. 1 and 2, a strip-shaped leaf spring abutting piece 31 is integrally projected at the central portion on one end side of the valve seat 7-1 provided with the flange 11. Then, between the leaf spring abutting piece 31 and the opening / closing valve 8, a leaf spring 33 having an arc-shaped cross section as shown in FIG. The leaf spring 33 is in contact with the leaf spring abutting piece 31 with the other end being a free end.
[0016]
The leaf spring 33 presses the opening / closing valve 8 against the valve seat 7-1 together with the coil spring 15-1 in the low rotation region of the engine, thereby closing the insertion-side tip 3a of the inlet pipe 3.
The plate spring 33 and the coil spring 15-1 are set so that the sum of both spring forces is equal to the spring force of the coil spring 15.
[0017]
Then, when the engine shifts to a high rotation range and the pressure difference between the expansion chamber 25 and the first volume chamber 29 rises above a predetermined value, the on-off valve 8 becomes the spring force of the coil spring 15-1 and the leaf spring 33. In contrast, the insertion-side tip 3a of the inlet pipe 3 is opened, but the leaf spring 33 opens the insertion-side tip 3a of the inlet pipe 3 at the same time as the opening / closing valve 8 is orthogonal to the longitudinal direction as shown in FIG. Bends in the direction of
[0018]
Thus, as shown in FIG. 8, the leaf spring having a circular arc cross section has a large reaction force with a small strain until it is bent as described above, but the reaction force becomes extremely small once the strain is increased and the tube is bent once. It has the property.
Therefore, in the present embodiment, the opening / closing valve 8 is opened as described above by utilizing the properties of the leaf spring, and at the same time, the reaction force of the opening / closing valve 8 is reduced by bending the leaf spring 33 as shown in FIG. It is comprised as follows.
[0019]
Since the pressure switching valve device 35 according to the present embodiment is configured as described above, when the pressure switching valve device 35 is attached to the muffler 5 instead of the pressure switching valve device 1 of FIG. Is pressed against the valve seat 7-1 by the spring force of the coil spring 15-1 and the leaf spring 33, and the insertion side tip 3a of the inlet pipe 3 is closed.
[0020]
When the engine shifts to a high rotation range and the pressure difference between the expansion chamber 25 and the first volume chamber 29 rises above a predetermined value, the on-off valve 8 resists the spring force of the coil spring 15-1 and the leaf spring 33. Then, since the insertion-side tip 3a of the inlet pipe 3 is opened, the internal pressure of the muffler 5 decreases.
However, as described above, in the present embodiment, the leaf spring 33 is bent as shown in FIG. 4 at the same time when the opening / closing valve 8 is opened, so that the reaction force of the opening / closing valve 8 becomes significantly smaller than the conventional one. Therefore, the opening / closing valve 8 does not immediately close the insertion-side tip 3a of the inlet pipe 3, but closes the insertion-side tip 3a with a slower closing operation than in the prior art.
[0021]
After the opening / closing valve 8 closes the insertion-side tip 3a, when the pressure difference between the expansion chamber 25 and the first volume chamber 29 rises again exceeding a predetermined value, the opening / closing valve 8 is turned into a coil spring 15-1 and a leaf spring. The insertion end 3a of the inlet pipe 3 is opened against the spring force of 33, and thereafter, the opening / closing valve 8 repeats the same operation.
Therefore, according to the present embodiment, chattering in which the opening / closing valve 8 repeats opening and closing instantaneously as in the prior art does not occur, and as a result, generation of abnormal noise due to chattering can be prevented.
[0022]
In addition, the attachment position of a leaf | plate spring is not limited to the said embodiment, Of course, the attachment position which can achieve the objective of this invention can be selected suitably.
Further, the attachment position of the pressure opening / closing valve device 35 is not limited to the inlet pipe 3, and may be attached to other muffler pipes according to the internal structure of the muffler.
[0023]
【The invention's effect】
As described above, according to the pressure open / close valve device according to each claim, chattering that the open / close valve repeats opening and closing instantaneously as in the past is not generated, and as a result, generation of abnormal noise due to chattering is prevented. I was able to do it.
[Brief description of the drawings]
FIG. 1 is a front view of a pressure switching valve device according to an embodiment of claims 1 and 2;
2 is a cross-sectional view taken along line II-II in FIG.
FIG. 3 is a perspective view of a leaf spring.
FIG. 4 is a perspective view of a bent leaf spring.
FIG. 5 is a cross-sectional view of a vehicle muffler equipped with a conventional pressure switching valve device.
FIG. 6 is a front view of a conventional pressure switching valve device.
7 is a cross-sectional view taken along line VII-VII in FIG.
FIG. 8 is a graph showing the relationship between the strain and reaction force of a coil spring and a leaf spring.
[Explanation of symbols]
3 Inlet pipe 7-1 Valve seat 8 On-off valve 13 Shaft 15-1 Coil spring 31 Leaf spring contact piece 33 Leaf spring 35 Pressure on-off valve device

Claims (2)

In a pressure on-off valve device provided with an on-off valve (8) that swingably attaches to a muffler pipe (3) of a vehicle muffler and opens and closes the muffler pipe in response to exhaust pressure.
The open / close valve (8) is closed by the spring force of the coil spring (15-1) and the leaf spring (33) having an arcuate cross section, and the muffler pipe (3) is closed. ), The muffler pipe (3) is opened against the spring force, and the leaf spring (33) is bent when the on-off valve (8) is opened to reduce the reaction force. Open / close valve device. The on-off valve (8) is swingably attached to a valve seat (7-1) attached to the exhaust gas flow downstream side open end (3a) of the muffler pipe (3) via a shaft (13). In addition, a coil spring (15-1) having one end (15a-1) in contact with the on-off valve (8) and the other end (15b-1) in contact with or locked to the valve seat (7-1) is inserted. A leaf spring (33) is installed between the valve seat (7-1) and the opening / closing valve (8) so that the leaf spring (33) can be bent along with the opening operation of the opening / closing valve (8). The pressure switching valve device according to claim 1.

Images