JPH0439388Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an exhaust bypass device for a turbocharger of an internal combustion engine.

[Conventional technology]

A turbocharger for a multi-cylinder internal combustion engine is known in which the inside of a turbine housing is divided into two parallel scroll passages. This is a so-called twin entry type turbocharger.
The aim is to effectively utilize the pressure waves of engine exhaust gas. That is, the cylinder group is divided into two so that pressure waves are not canceled out, and the exhaust gas from each cylinder group is guided to the respective divided scroll passages. In order to control the upper limit of boost pressure, turbochargers require a valve device (so-called wastegate valve) that bypasses exhaust gas when boost pressure exceeds a predetermined value, but in this twin entry type, there are two flow paths. Therefore, it is necessary to devise ways to control the bypass from each scroll passage. Therefore, in 1988,
In Publication No. 88018 and Japanese Utility Model Application No. 56-154532, a bypass passage that opens to each scroll passage is provided in the turbine housing, and the bypass passage is opened and closed by a waste gate valve located in the housing. is proposed.

In addition, the applicant of the present application has previously proposed a control valve structure for improving the sealing performance of a bypass control valve constituting a wastegate valve of a twin-entry turbocharger (Utility Application No. 35320/1982). As shown in FIG. 8, this bypass control valve has a support shaft 3 supported by a bearing 34 provided in the turbine housing.
6 and two valve bodies 26a and 26b provided at the tip of the support shaft 36.
A clearance is provided between the bearing 34 and the bearing 34 to reduce sliding resistance.

[Problem that the invention attempts to solve]

Therefore, the support shaft 36 of the bypass control valve is
It will be inclined with respect to the bearing 34 within this clearance. However, each valve body 26a, 26
b is the longitudinal positional relationship of the support shaft 36.
6, there is a problem that when the support shaft 36 is tilted in this manner, the valve body 26b that is farther from the bearing 34 tends to float off its valve seat when viewed from the bearing 34 as a fulcrum.

If one of the valve bodies opens in the fully closed region of the wastegate valve, part of the exhaust gas flows through the bypass passage, causing a problem in which the supercharging pressure decreases.

[Means for solving problems]

The exhaust bypass device for a turbocharger according to the present invention connects bypass passages to a plurality of scroll passages formed circumferentially in a turbine housing, respectively arranges a bypass control valve in each of these bypass passages, and controls each of the bypass control valves. ,
The support shaft is connected to a support shaft fitted to a bearing provided in a turbine housing through a common arm member in a longitudinal positional relationship of the support shaft, wherein the common arm member controls the bypass control valve. The bypass control valve is composed of a first arm member that is connected to each other and a second arm member that is fixed to the support shaft, and each bypass control valve is arranged in a radial direction of the valve shaft with respect to the first arm member through which the valve shaft passes. and are connected via a clearance so as to be displaceable in the axial direction of the valve shaft, and the first
The arm member has a second pin fixed to the arm member.
connected to the arm member via a clearance so as to be displaceable in the radial direction of the pin and the axial direction of the pin;
Further, the connecting portion between the first arm member and the second arm member is provided with a detent for restricting rotation of the first arm member with respect to the second arm member.

[Effect]

A first arm member connecting the bypass control valve so as to be displaceable in the radial and axial directions of the valve shaft and a second arm member extending from the support shaft are connected with a clearance around the pin of the first arm member. Therefore, even if the support shaft/second arm member is inclined with respect to the valve seat surface, this inclination can be absorbed by the connecting portion between the arms. Furthermore, even if the valve seat surfaces of each bypass control valve are inclined or have a step difference, the clearance around the valve shaft of the bypass control valve passing through the first arm member allows the bypass control valve to complement the valve seat surface. These two inclinations allow for secure seating.

〔Example〕

In FIG. 4, the turbocharger 10 has a compressor housing 12 and a turbine housing 14, and a compressor impeller and a turbine wheel (not shown) connected by a common turbine shaft are arranged in these housings, respectively. . The compressor housing 12 includes
Air is passed through as indicated by arrow A, supplying air to the internal combustion engine via the intake manifold 16. Exhaust gas is passed through the turbine housing 14 as shown by arrow G. In this case, the exhaust manifolds 18a and 18b are divided into two parts in consideration of the ignition order to prevent exhaust interference, and correspondingly, the turbine housing 14
The scroll passages formed in the scroll passages are also formed so as to extend in parallel in the circumferential direction, as shown by 20a and 20b.

As shown in FIG. 5, one scroll passage 20b has an end surface 22 of the turbine housing 14.
A bypass passage 24b opening to the other scroll passage 20a is connected to the other scroll passage 20a.
A bypass passage 24a opening to the same end face 22 through the radially outer side of b is connected to the bypass passage 24a. The bypass passages 24a, 24b open on the same plane of the end surface 22, and the end surface portions surrounding these openings serve as valve seats for the bypass control valves 26a, 26b.

Note that the scroll passages 20a, 2 extending in the circumferential direction
There is a space 28 (Fig. 6) in the center of 0b for housing a turbine wheel (not shown), and this space 28 and bypass passages 24a, 24b are open and cover the end face 22 which becomes the valve seat. , an annular raised wall 30 is formed, and an exhaust pipe 32 is connected using this raised wall 30 as a flange.

A hole is provided radially through this annular raised wall 30, and a bearing (bushing) 34 is fitted into this hole. A support shaft 36 is fitted into the bearing 34 .
Between this bearing 34 and the support shaft 36 (small)
There is clearance and the support shaft 36 can be tilted relative to the bearing 34. Each end of the support shaft 36 projects from the bearing 34, and one end of a link 38 is welded to the outwardly projecting shaft end. The link 38 extends perpendicularly from the support shaft 36, and has a pin 40 erected at the other end. An actuator rod 42 engages the pin 40. This actuator rod 42 is connected to a known diaphragm actuator 44 (FIG. 4) which operates in response to the boost pressure of the intake manifold 16. Therefore, the support shaft 36 can rotate depending on the supercharging pressure of the intake manifold 16. however,
Because the force transmitted through link 38 includes a component that pulls support shaft 36 in a direction perpendicular to its axis, support shaft 36 tilts within bearing 34 as described above.

The above-mentioned bypass control valves 26a and 26b are supported by a common arm member at a portion of the support shaft 36 that protrudes inward from the bearing 34. As shown in FIGS. 1-6, this common arm member consists of a first arm member 46 and a second arm member 48. First arm member 4
6 is formed into a plate shape extending parallel to the support shaft 36 in order to connect the two bypass control valves 26a and 26b. Therefore, when viewed in the axial direction of the support shaft 36, one of the bypass control valves 26b is larger than the other. It is located further away than the bearing 34. And each bypass control valve 2
The valve shaft 26c of 6a, 26b is the first arm member 4
After being inserted into the hole 46a provided in 6, the washer is caulked. At this time, the hole 46a and the valve shaft 26c
A clearance is secured between the bypass control valves 26a and 26b so that the bypass control valves 26a and 26b can swing freely relative to the first arm member 46. This is to allow manufacturing errors of parts and the like, and to ensure that the bypass control valves 26a, 26b are seated on their valve seats.

The second arm member 48 is generally T-shaped, and the top of the T-shape is formed as a cylindrical portion 50 that can be fitted onto the support shaft 36 . A notch 50a is provided in the cylindrical portion 50, and a second
After the arm member 48 is fitted onto the support shaft 36, welding is performed using the notch 50a.
A T-shaped foot 52 of the second arm member 48 extends perpendicularly from the tubular portion 50 and has a hole 48a near its tip.
is formed. On the other hand, the first arm member 46
A pin 54 is fixed to the intermediate portion of the arm member 48, and the first and second arm members 46 and 48 can be connected by passing the pin 54 through the hole 48a. However, this connection does not fix the two, but allows them to move relative to each other within a limited range. That is, there is a clearance between the pin 54 and the hole 48a, and there is also a clearance between the washer 56 caulked to the tip of the pin 54 and the second arm member 48.
Therefore, the first arm member 46 can swing relative to the second arm member 48.
As a result, even if the support shaft 36 is tilted, as shown in FIG. The first arm member 46 is tilted again with respect to the arm member 48, so that the first arm member 46 occupies a position substantially parallel to the valve seat, so that one bypass control valve 26b does not float. FIG. 3 further shows a first arm member 46.
Drooping parts 52a and 52b are provided on the second arm member 48 so as to sandwich the long sides extending in parallel to each other,
It forms a rotation stopper for the first arm member 46 which can move almost freely.

As explained above, according to the present invention, the support shaft 3
Even if 6 is tilted, both bypass control valves 26a, 26b
can be securely seated on each valve seat. Further, according to the present invention, the bypass control valves 26a and 26b can be reliably closed even if the valve seat surface is deformed due to thermal distortion or the like. 7th
The figure shows a state in which the valve seats formed by the end faces 22 around the openings of the bypass passages 24a, 24b are inclined with respect to each other. The second arm member 48 is inclined with respect to the valve seat (of the right bypass control valve 26a) together with the support shaft 36. Even in this case, the force transmitted from the actuator rod 42 to the support shaft 36 is transferred from the second arm member 48 fixed to the support shaft 36 to the first arm member 46 at the force application point A. Reportedly. At this time, the first arm member 46 can assume a substantially free posture relative to the second arm member 48 in correspondence with the valve seat surface. In addition, each bypass control valve 26
a, 26b can also take a free attitude with respect to the first arm member 46. Therefore, the first arm member 46 pushes the bypass control valves 26a, 26b toward their respective valve seats at the force application points B, C, respectively, and the bypass control valves 26a, 26
b are securely seated in each.

[Effect of idea]

As explained above, according to the present invention, two bypass control valves can be controlled by a single actuator, and both bypass control valves can be securely seated by absorbing the inclination of the support shaft and the deformation of the valve seat surface. You can force it.

[Brief explanation of the drawing]

Figure 1 is an enlarged view of the main part of Figure 6, Figure 2 is a sectional view taken along the line - in Figure 1, Figure 3 is a sectional view taken along the line - in Figure 1, and Figure 4 is the main part. A front view of the turbocharger according to the invention, FIG. 5 is a sectional view taken along the line - of FIG. 4, FIG. 6 is a side view of the turbine housing of FIG. 4, and FIG. 7 illustrates the seated state of the bypass control valve. 8 are diagrams explaining the prior art. 14...Turbine housing, 20a, 20b
...Scroll passage, 24a, 24b...Bypass passage, 26a, 26b...Bypass control valve, 3
4... Bearing, 36... Support shaft, 46, 48... Arm member.

Claims (1)

[Scope of utility model registration request] A bypass passage is connected to each of the plurality of scroll passages formed in the circumferential direction of the turbine housing, a bypass control valve is disposed in each of the bypass passages, and each of the bypass control valves is fitted into a bearing provided in the turbine housing. In the exhaust bypass device for a turbocharger, the turbocharger exhaust bypass device is connected to a support shaft in the longitudinal direction of the support shaft via a common arm member. Each bypass control valve consists of a first arm member and a second arm member fixed to the support shaft, and each bypass control valve has a radial direction of the valve shaft and an axis of the valve shaft with respect to the first arm member through which the valve shaft passes. The first arm member is connected via a clearance so as to be displaceable in the direction, and the first arm member has a clearance so as to be displaceable in the radial direction of the pin and the axial direction of the pin with respect to the second arm member through which the pin fixed to the first arm member is passed. the first arm member and the second arm member.
1. An exhaust bypass device for a turbocharger, wherein a detent is provided at a connecting portion with the arm member to restrict rotation of the first arm member relative to the second arm member.