JPH09100725A - Exhaust bypass device of turbo charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts and to reduce the number of assembling steps by providing a bypass valve in an exhaust flow passage bypassing a turbine rotor and integrally forming a bracket for supporting an actuator for actuating this bypass valve in the compressor housing of a turbo charger. SOLUTION: An exhaust flow passage 11 bypassing a turbine rotor is formed in a turbine housing 3, a bypass valve 13 is provided in the exhaust flow passage 11, the bypass valve 13 is attached to an arm 15 rotated around a rotary shaft 14 and a sub arm 16 is integrally formed in the arm 15. The sub arm 16 is connected via a rod 17 to an actuator 18 provided in a compressor housing 2 side. The actuator 18 is provided with a spring 19 for pressing the bypass valve 13 in an opening/closing direction and this spring 19 is supported on a bracket 20 integrally formed in the compressor housing 2. Thus, the number of parts is reduced and the number of assembling steps is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger used as a supercharger for an internal combustion engine, and more particularly to an exhaust bypass device for controlling supercharging pressure.

[0002]

2. Description of the Related Art A turbocharger is a compressor rotor in which a compressor rotor and a turbine rotor are connected back to back via a rotary shaft, and the turbine rotor is rotated by exhaust gas from an internal combustion engine such as a gasoline engine to rotate the compressor rotor. The intake air is pressurized by and supplied to the internal combustion engine.

By the way, in such a turbocharger, as the flow rate and flow velocity of the exhaust gas increase,
Since the rotation speed of the turbine rotor, that is, the rotation speed of the compressor rotor is increased, the boost pressure is excessively increased, which causes knocking of the internal combustion engine. Therefore, an exhaust bypass device that allows exhaust gas to bypass the turbine rotor is provided to suppress the rotation speed of the turbine rotor and control the supercharging pressure to be equal to or lower than a predetermined pressure.

This exhaust bypass device is composed of a bypass valve that opens and closes an exhaust passage formed by bypassing the turbine rotor, and an actuator that opens and closes the bypass valve. Conventionally, this actuator has been fastened to a compressor housing of a turbocharger with a bolt / nut or the like via a bracket made of sheet metal.

[0005]

However, when the actuator is mounted on the compressor housing via the bracket made of sheet metal as described above, the number of parts increases and the number of assembling steps increases. Further, since the supporting rigidity of the actuator cannot be sufficiently increased, vibration is generated while the vehicle is running and the bolts and nuts are loosened, resulting in poor stability.

[0006]

In order to solve the above problems, the present invention comprises a bracket for supporting the above-mentioned actuator, which is formed integrally with a compressor housing of a turbocharger.

Thus, if the bracket for supporting the actuator is integrally formed with the compressor housing,
Since the number of parts is reduced, the number of assembly steps can be reduced and
Vibration is suppressed because the support rigidity of the actuator is improved.

[0008]

Embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the turbocharger 1 is
A compressor housing 2 containing a compressor rotor (centrifugal type), a turbine housing 3 containing a turbine rotor (radial type), and a center housing 4 containing a rotating shaft connecting the compressor rotor and the turbine rotor. Has been done.

Exhaust gas 6 of an internal combustion engine such as a gasoline engine is introduced into the turbine housing 3 from the outside in the radial direction through an inlet portion 5. The exhaust gas 6 rotates the turbine rotor in the turbine housing 3 and then the outlet 7
Is discharged axially through. As a result, the compressor rotor rotates, the intake air 9 is sucked into the compressor housing 2 from the axial direction through the inlet portion 8, is pressurized by the compressor rotor, and is then discharged radially outward through the outlet portion 10 to a predetermined value. Is supplied to the internal combustion engine at a supercharging pressure of.

As shown in FIG. 3, the turbine housing 3 is formed with an exhaust passage 11 that bypasses the turbine rotor. The exhaust passage 11 is formed of a hole formed in an inlet nozzle 12 that guides exhaust gas to the turbine housing 3, and short-circuits the inlet portion 5 and the outlet portion 7 of the turbine housing 3 without a turbine rotor. .

A bypass valve 13 is provided in the exhaust passage 11.
Is provided. The bypass valve 13 is attached to the arm 15 that rotates around the rotation shaft 14, and opens and closes the exhaust passage 11 as the arm 15 swings. A sub-arm 16 is integrally provided on the arm 15, and the arm 15 swings as the sub-arm 16 swings. The sub-arm 16 is exposed to the outside of the turbine housing 3 and is connected via a rod 17 to an actuator 18 provided on the compressor housing 2 side.

The actuator 18 has a spring 19 for urging the bypass valve 13 in the valve closing direction.
9 is supported by a bracket 20 formed integrally with the compressor housing 2. The bracket 20 is
It is composed of a plate portion 20a extending radially outward from the compressor housing 2 in a substantially triangular shape, and a tubular cup portion 20b integrally formed at the apex of the plate portion 20a.

The bracket 20 is formed integrally with the aluminum compressor housing 2 by casting, forging, inexpensive die casting, or the like. If the bracket 20 supporting the actuator 18 is integrally formed with the compressor housing 2 as described above, the number of parts can be reduced and the number of assembling steps can be reduced.
Since the support rigidity of 8 is improved, vibration is suppressed.

In the cup portion 20b of the bracket 20,
The spring 19 of the actuator 18 is housed and protected from dust and the like. One end of the spring 19 has the cup portion 2
0b is in contact with the bottom 21 and the other end is in contact with the retainer 22 connected to the rod 17, and the spring force of the retainer 22 sets them apart. Rod 1
7 penetrates the hole 23 formed in the bottom portion 21 and the spring 19
It is arranged in parallel with and is prevented from being twisted by the spring 19.

According to this structure, the exhaust gas force Fg acting on the bypass valve 13 is taken into consideration in the lever ratio between the arm 15 and the sub arm 16, and the spring 1 of the actuator 18 is considered.
When it becomes larger than the setting force Fs of 9, the bypass valve 1
3 is opened and part of the exhaust gas bypasses the turbine rotor and is released. As a result, the rise in supercharging pressure can be suppressed.

As shown in FIG. 3, the cup portion 20b
A diaphragm 24 may be provided in the opening of the compressor and a part of the intake air pressurized from the outlet 10 of the compressor may be guided to the diaphragm. In this case, since the diaphragm force Fa increases as the supercharging pressure of the outlet 10 increases, the bypass valve 13
Will be opened and the rise in boost pressure will be suppressed.

[0018]

As described above, according to the exhaust bypass device for a turbocharger of the present invention, the number of parts can be reduced, so that the number of assembling steps can be reduced, and the supporting rigidity of the actuator is improved, so that the vibration can be suppressed. .

[Brief description of the drawings]

FIG. 1 is a side view of a turbocharger including an exhaust bypass device according to an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a view showing a cross section of the exhaust bypass device.

[Explanation of symbols]

 2 Compressor housing 11 Exhaust flow path 13 Bypass valve 18 Actuator 20 Bracket

Claims (1)

[Claims] 1. An exhaust bypass device for a turbocharger, comprising a bypass valve provided in an exhaust flow path bypassing a turbine rotor and an actuator for operating the bypass valve, wherein a bracket supporting the actuator is attached to the turbocharger. An exhaust bypass device for a turbocharger, which is formed integrally with a compressor housing.