Turbocharger housing and turbocharger
The turbocharger housing design addresses VTG bushing cracks by surrounding it with a cooling water jacket, ensuring effective cooling and preventing structural damage, thus maintaining the integrity of the turbocharger.
Patent Information
- Application Number
- JP2025125504
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-07-31
- Filing Date
- 2025-07-28
- Publication Date
- 2026-02-16
AI Technical Summary
Conventional turbocharger bearing housings with variable turbine geometry (VTG) suffer from cracks due to high thermomechanical loads, particularly at the uncooled VTG bushing area, despite the presence of a cooling water jacket, leading to potential leaks and structural damage.
A turbocharger housing design with a cooling water jacket surrounding the VTG bushing, forming a cavity with multiple passages to enhance cooling, including a central passage and two peripheral passages, effectively cooling the VTG bushing and adjacent areas to prevent crack formation.
The enhanced cooling system prevents cracks in the VTG bushing area, maintaining structural integrity without material changes or additional components, allowing for advanced applications with gray cast iron housings and minimal additional effort or cost.
Smart Images
Figure 2026025972000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a turbocharger housing and to a turbocharger equipped with such a turbocharger housing. [Background technology]
[0002] The use of turbochargers helps improve the efficiency of internal combustion engines. Such exhaust turbochargers are responsible for feeding compressed air into the internal combustion engine. The compressor of the exhaust turbocharger is driven by an exhaust gas-driven turbine. The rotation of the turbine wheel, caused by the exhaust gases of the internal combustion engine, is transmitted via a shaft to the compressor wheel, which compresses and feeds the air. Internal combustion engines can be used in vehicles, such as passenger cars, in combination with exhaust turbochargers. Turbochargers can also be used in combination with fuel cells.
[0003] The turbocharger housing includes a turbine housing for the turbine wheel, a compressor housing for the compressor wheel, and a bearing housing for the shaft. The bearing housing connects the turbine housing and the compressor housing. Conventional bearing housings can be made of gray cast iron.
[0004] The efficiency and power output of an internal combustion engine can be improved by increasing the temperature of the exhaust gases that drive the turbocharger turbine, but this leads to an increase in the thermomechanical load on the bearing housing due to the concomitant increase in the thermal energy supplied by the exhaust gases.
[0005] To allow for temperature reduction, a cooling water jacket (also called a cooling jacket or jacket cooler) can be incorporated into the bearing housing. However, the residual loads can exceed the strength of gray cast iron, which can cause cracks in the flange on the turbine side of the bearing housing. Such cracks can lead to leaks.
[0006] A turbocharger with variable turbine geometry (VTG) includes adjustable guide blades located within a turbine housing between a volute and a turbine wheel. The guide blades affect gas flow to the turbine wheel. The variable turbine geometry assembly includes guide blades coupled to an adjustment shaft, whereby rotational movement of the adjustment shaft causes rotational movement of the guide blades, thereby affecting gas flow to the turbine wheel.
[0007] In conventional turbochargers with variable turbine geometry, the VTG bushing through which the adjusting shaft runs is located in the bearing housing and is located outside the area cooled by the cooling water jacket. This means that the uncooled area is exposed to high thermomechanical loads that can lead to cracks near the bushing. In conventional bearing housings, most cracks occur in the area of the VTG bushing, despite the presence of the cooling water jacket. Summary of the Invention [Problem to be solved by the invention]
[0008] The object of the present invention is to relieve stress and thereby prevent cracks from occurring. [Means for solving the problem]
[0009] This problem is solved by a turbocharger housing and a turbocharger having the features of the independent claims.
[0010] A turbocharger housing for a turbine with a variable turbine geometry that is adjustable by an adjustment shaft includes a turbine housing and a bearing housing having a longitudinal axis and including a VTG bushing for the adjustment shaft. The VTG bushing is spaced from the longitudinal axis. The bearing housing includes a cooling water jacket including an inlet and an outlet, and the cooling water jacket surrounds the VTG bushing.
[0011] The cooling water jacket is formed by a cavity in the wall of the bearing housing, while the inlet and outlet openings are on the outside of the bearing housing. Cooling water flows through the cavity from the inlet to the outlet. A surrounding cavity surrounds the VTG bushing, thereby providing cooling for this area.
[0012] The cooling water jacket surrounding the VTG bushing allows for improved cooling in the area of the VTG bushing. This prevents cracks from forming in this area, which is the most likely to cause damage in conventional designs. This allows for more advanced applications to be designed without changing the component material or preparing additional components. Gray cast iron can still be used as the housing material. There is no significant increase in effort or cost compared to conventional designs.
[0013] However, minor modifications to the VTG kinematics, VTG bushing, and adjusting shaft assembly may be necessary. The VTG bushing may be longer than conventional VTG bushings because it is surrounded by a cooling water jacket that requires additional space in the bearing housing. This may complicate assembly of the adjusting shaft assembly into the bearing housing, especially if the bearing housing incorporates a backplate.
[0014] A turbocharger having such a turbocharger housing includes a turbine housing, a turbine wheel disposed within the turbine housing, and a variable turbine geometry assembly adjustable by an adjustment shaft. The bearing housing has a longitudinal axis and includes a VTG bushing through which the adjustment shaft extends. The VTG bushing is spaced from the longitudinal axis. The bearing housing includes a cooling water jacket having an inlet and an outlet, the cooling water jacket surrounding the VTG bushing.
[0015] The variable turbine geometry assembly includes a plurality of movable guide blades coupled to an adjustment shaft such that rotational movement of the adjustment shaft translates to rotational movement of the guide blades, thereby adjusting the plurality of guide blades. In other words, rotation of the adjustment shaft adjusts the plurality of guide blades. Adjustment of the guide blades affects exhaust flow to the turbine wheel. In one embodiment, the adjustment shaft protrudes from the bearing housing.
[0016] The bearing housing and the turbine housing are connected to each other and have longitudinal axes that coincide with the rotational axes of the turbine wheel and the shaft.
[0017] The cooling water jacket is formed by a cavity within the wall of the bearing housing. Cooling water enters the cooling jacket through an inlet and exits the cooling jacket through an outlet. In one embodiment, the cooling water jacket completely surrounds the longitudinal axis and the VTG bushing.
[0018] In one embodiment of the turbocharger housing or turbocharger, the cooling water jacket includes a central passage between the longitudinal axis and the VTG bushing. A shaft extends along the longitudinal axis through the turbocharger bearing housing, where the shaft is coupled to the turbine wheel. Compared to a conventional cooling water jacket, additional arms are provided around the VTG bushing. The cooling water jacket extends into three passages: a central passage and two peripheral passages that later reunite. The peripheral passages extend around the longitudinal axis and the VTG bushing away from the central passage. Thus, the longitudinal axis and the VTG bushing are surrounded all around by multiple passages.
[0019] In one embodiment, the cross section of the cooling water jacket includes an outer contour line perpendicular to the longitudinal axis with a radial extension that surrounds the VTG bushing. Additionally, there is a first inner contour line that surrounds the longitudinal axis and a second inner contour line that surrounds the VTG bushing. This configuration forms an extended cooling area that includes the area of the VTG bushing.
[0020] In one embodiment, the outer contour is a continuous curve with a circular base shape and a bell-shaped radial extension. Additionally or alternatively, the second inner contour is a circular line. The annular base shape corresponds to the flange that forms the turbine side of the bearing housing. Furthermore, the bell-shaped radial extension incorporates the VTG bushing area into the cooling area.
[0021] In one embodiment, the central flow passage between the longitudinal axis and the VTG bushing extends axially farther toward the turbine housing than the peripheral flow passages that extend around the VTG bushing in radial extensions. This provides better cooling of the central region. The flatter peripheral flow passages at the periphery of the VTG bushing provide a good compromise between adequate cooling and compact size.
[0022] In one embodiment, the longitudinal axis and the VTG bushing are arranged parallel to or at an acute angle to one another, which allows for operation of the VTG assembly from below the turbine.
[0023] In one embodiment, the turbine housing includes a volute for the incoming gases, the volute including an inlet section and a tongue section that defines an end of the volute adjacent the inlet section. The radial extension is aligned with the inlet section or the tongue section. Thus, the expanded cooling area around the VTG bushing is aligned with the turbine section that experiences high thermal loads from the incoming hot gases. To achieve a compact structure, the adjustment shaft is located below the inlet section or the tongue section.
[0024] The turbocharger described above may be used in combination with an internal combustion engine or a fuel cell.
[0025] In the drawings, parts that are the same or have the same function are provided with the same reference numerals. [Brief explanation of the drawings]
[0026] [Figure 1] 1 is a schematic diagram illustrating an example of a turbine having variable turbine geometry. [Figure 2] FIG. 1 is a schematic view showing an example of a conventional bearing housing. [Figure 3] FIG. 1 is a diagram showing an example of a conventional cooling water jacket. [Figure 4] FIG. 2 is a schematic diagram illustrating an embodiment of a bearing housing. [Figure 5] FIG. 2 is a diagram showing an example of a cooling water jacket. [Figure 6] FIG. 2 is a cross-sectional view of one embodiment of a bearing housing. DETAILED DESCRIPTION OF THE INVENTION
[0027] Figure 1 shows a schematic diagram of a turbine 1 with variable turbine geometry. This is a cross section perpendicular to the axis of rotation. The turbine 1 is part of an exhaust turbocharger that also includes a compressor.
[0028] The turbine 1 includes a turbine housing 3 and a turbine wheel 5 disposed within the turbine housing 3. The function of the turbine housing 3 is to direct exhaust gases to the turbine wheel 5. A shaft 7 connects the turbine wheel 5 to a compressor wheel (not shown in FIG. 1) disposed within a compressor housing (not shown in FIG. 1), thereby transmitting rotation of the turbine wheel 5 to the compressor wheel. A bearing housing 9 (not shown in FIG. 1) is disposed between the turbine 1 and the compressor.
[0029] The turbine housing 3 includes a volute 11 used to direct incoming gases around the turbine wheel 5. The helical configuration of the volute 11 defines a tongue 13 at the end of the volute 11 near the inlet 15. An annular slot 17 is defined between the volute 11 and the turbine wheel 5, through which exhaust gases flow from the volute 11 to the turbine wheel 5. A variable turbine geometry assembly (VTG assembly) 19 defines the bottom of the slot 17. The VTG assembly 19 includes pivotable guide blades 21 positioned within the slot 17. The angle of the guide blades 21 can be varied relative to the radial direction to affect the exhaust flow from the volute 11 to the turbine wheel 5. An adjustment shaft 23 extends from the VTG assembly 19, spaced from the guide blades 21. The guide blades 21 are coupled to the adjustment shaft 23, such that rotational movement of the adjustment shaft 23 is converted into rotational movement of the guide blades 21, thereby adjusting the angle of the guide blades 21 relative to the radial direction. The position of the adjustment shaft 23 is indicated by a dashed line.
[0030] The turbine 1 is coupled to a bearing housing 9 located below the VTG assembly 19. The adjustment shaft 23 passes through a VTG bushing 25 within the bearing housing 9. Due to the hot exhaust gas temperatures, most of the thermal stress occurs at the inlet 15 of the volute 11.
[0031] FIG. 2 shows a schematic cross-sectional view of a conventional bearing housing 9, which includes a cooling water jacket 27 inside the bearing housing 9. The conventional cooling water jacket 27 is defined by a cavity surrounded by the walls of the bearing housing 9 and is shown in FIG. 3. The cooling water jacket 27 includes an inlet 29 and an outlet 31 having a tubular shape. The cooling water jacket 27 surrounds the shaft 7, which passes through the bearing housing 9 along the longitudinal axis 33 of the bearing housing 9. Between the inlet 29 and the outlet 31, the cooling water jacket 27 forms two flow paths on either side of the shaft 7. The VTG bushing 25 is located outside the cooling water jacket 27. The cross-section of the cooling water jacket 27 has a basic annular shape between the inlet 29 and the outlet 31. This annular shape narrows in the region between the shaft 7 and the adjusting shaft 23 to accommodate the VTG bushing 25.
[0032] This narrowing reduces cooling in the area of the VTG bushing 25, which can lead to cracks in this area. This effect is exacerbated when the VTG bushing 25 is located near the inlet 15 or tongue 13 of the volute 11. The combination of high temperature exhaust flow through the bearing housing area and insufficient cooling significantly increases the risk of crack formation.
[0033] Temperature lines 57 and 55 show the extent of the area of greatest thermomechanical stress in the peripheral region where the hot exhaust gases enter. Between temperature lines 57 and 55, the stress is slightly lower than outside temperature line 57.
[0034] 4 shows a schematic cross-sectional view of the bearing housing 9 containing the cooling water jacket 27 of the present invention. The wall of the cooling water jacket 27 defined by the cavity of the bearing housing 9 is shown in FIG.
[0035] The cooling water jacket 27 includes a tubular inlet 29 and an outlet 31. The cooling water jacket 27 surrounds not only the shaft 7 but also the VTG bushing 25 through which the adjustment shaft 23 passes. The cooling water jacket 27 includes, in particular, two channels on either side of the shaft 7. A central channel 39 is located between the longitudinal axis 33 and the VTG bushing 25. The peripheral channels 37, 35 are located on the sides of the longitudinal axis 33 and the VTG bushing 25 that are spaced apart from each other.
[0036] A cross section of the cooling water jacket 27 perpendicular to the longitudinal axis 33 has an outer contour 41. In the area of the VTG bushing 25, the outer contour 41 has a radial extension 47, thereby surrounding the VTG bushing 25. The outer contour 41 is a continuous curve with a circular basic shape with the bell-shaped radial extension 47. A first inner contour 43 surrounds the longitudinal axis 33, more precisely the opening for the shaft 7, and a second inner contour 45 surrounds the VTG bushing 25. The second inner contour 45 is circular. This divides the cooling water jacket 27 into three channels, one central and two peripheral. These channels 39, 35, and 37 conduct the cooling water around the shaft 7 and the VTG bushing 25.
[0037] The cooling water jacket 27 has an extended area in the vicinity of the VTG bushing 25. Such a configuration is used to cool the VTG bushing 25 and the inlet section 15 of the volute 11. The geometry of the cooling system prevents the development of temperature-induced stresses in the area of the VTG bushing 25, thereby preventing the formation of cracks.
[0038] FIG. 6 shows a cross section of the bearing housing 9 along the longitudinal axis 33, which cross section illustrates half of the part.
[0039] The bearing housing 9 includes a turbine side 49 facing the turbine 1 and an opposite compressor side 51 facing the compressor. The bearing housing 9 connects the turbine housing 3 and the compressor housing. The bearing housing 9 supports the mechanical loads of the rotating components and withstands and dissipates the thermal loads transmitted from the turbine side. The turbine side 49 of the bearing housing 9 forms a flange that extends toward the volute 11 and is connected to the turbine housing 3. The VTG bushing 25 is located within the bearing housing 9 below the VTG assembly 19. The VTG bushing 25 is press-fit into the housing to prevent movement or detachment. In this embodiment, the longitudinal axis 33 and the VTG bushing 25 extend parallel to each other.
[0040] The adjusting shaft 23 is coupled to the VTG assembly 19 and protrudes from the bearing housing 9 through the VTG bushing 25. The lever 53 is coupled to the adjusting shaft 23 on the outside of the bearing housing 9. The lever 53 extends radially relative to the adjusting shaft 23, and rotational movement of the lever 53 causes rotational movement of the adjusting shaft 23, thereby adjusting the guide blade 21.
[0041] Cooling water jacket 27 includes a central passage 39 that extends between shaft 7 and VTG bushing 25 along longitudinal axis 33. Central passage 39 is located below turbine wheel 5. Peripheral passages 35 are located on the peripheral side of VTG bushing 25, below VTG assembly 19 and / or volute 11. VTG bushing 25 and shaft 7 are therefore surrounded by cooling water jacket 27.
[0042] The central flow passage 39 located between the longitudinal axis 33 and the VTG bushing 25 extends axially further towards the turbine housing 3 than the peripheral flow passages 35 which extend around the VTG bushing 25 at the radial extension 47.
[0043] The features described above and in the claims and which can be seen from the drawings can be advantageously implemented both individually and in various combinations. The invention is not limited to the described embodiments, but can be modified in various ways within the skill of those skilled in the art. [Explanation of symbols]
[0044] 1 turbine 3 Turbine housing 5. Turbine Wheel 7 shaft 9 Bearing housing 11 Spiral section 13 tongue 15 Entrance 17 slots 19 VTG Assembly 21 Guide Blade 23 Adjustment shaft 25 VTG Bush 27 Cooling water jacket 29 Inlet 31 Outlet 33 Longitudinal axis 35, 37 Peripheral flow path 39 Central Channel 41 Outer contour line 43 First inner contour 45 Second inner contour 47 Extension 49 Turbine side 51 Compressor side 53 Lever 55, 57 temperature line
Claims
1. A turbocharger housing for a turbine (1) with a variable turbine geometry that is adjustable by means of an adjustment shaft (23), comprising: a turbine housing (3); a bearing housing (9) having a longitudinal axis (33) and having a VTG bushing (25) for the adjustment shaft (23), the VTG bushing (25) being spaced apart from the longitudinal axis (33); The bearing housing (9) includes a cooling water jacket (27) including an inlet (29) and an outlet (31), and the cooling water jacket (27) surrounds the VTG bushing (25).
2. 2. The turbocharger housing of claim 1, wherein the cooling water jacket also circumscribes the longitudinal axis and includes a central flow passage between the longitudinal axis and the VTG bushing.
3. The cross section of the cooling water jacket (27) is an outer contour (41) having a radial extension (47) surrounding said VTG bushing (25); a first inner contour (43) surrounding said longitudinal axis (33); a second inner contour (45) surrounding the VTG bushing (25); 3. The turbocharger housing of claim 1 or 2, comprising:
4. said outer contour (41) being a continuous curve with a circular basic shape having a bell-shaped radial extension (47); and / or 4. The turbocharger housing of claim 3, wherein the second inner contour line (45) is a circular line.
5. 5. The turbocharger housing of claim 3, wherein a central flow passage (39) between the longitudinal axis (33) and the VTG bushing (25) extends axially further towards the turbine housing (3) than a peripheral flow passage (35) extending around the VTG bushing (25) at the radial extension (47).
6. The turbocharger housing according to any one of claims 1 to 5, wherein the longitudinal axis (33) and the VTG bushing (25) are arranged parallel to each other or at an acute angle.
7. A turbocharger, a turbine housing (3); a turbine wheel (5) disposed within the turbine housing (3); a variable turbine geometry assembly (19) adjustable by an adjustment shaft (23); a bearing housing (9) having a longitudinal axis (33) and a VTG bushing (25) through which the adjustment shaft (23) extends; Including, The VTG bushing (25) is spaced from the longitudinal axis (33); The bearing housing (9) includes a cooling water jacket (27) including an inlet (29) and an outlet (31); The cooling water jacket (27) surrounds the VTG bushing (25).
8. a shaft (7) extending through the bearing housing (9) along the longitudinal axis (33); The shaft (7) is connected to the turbine wheel (5), 8. The turbocharger of claim 7, wherein the cooling water jacket (27) also surrounds the shaft (7) and includes a central flow passage (39) between the shaft (7) and the VTG bushing (25).
9. The cross section of the cooling water jacket (27) is an outer contour (41) having a radial extension (47) surrounding said VTG bushing (25); a first inner contour (43) surrounding said shaft (7); a second inner contour (45) surrounding the VTG bushing (25); 9. The turbocharger of claim 8, comprising:
10. said outer contour (41) being a continuous curve with a circular basic shape having a bell-shaped radial extension (47); and / or 10. The turbocharger of claim 9, wherein the second inner contour line (45) is a circular line.
11. 11. A turbocharger according to claim 9 or 10, wherein the central flow passage (39) between the shaft (7) and the VTG bushing (25) extends axially further towards the turbine housing (3) than peripheral flow passages (35) that extend around the VTG bushing (25) at the radial extension (47).
12. The turbocharger according to any one of claims 8 to 11, wherein the shaft (7) and the VTG bushing (25) are arranged parallel to each other or at an acute angle to each other.
13. The turbine housing (3) includes a volute (11) for introducing gas, the volute (11) including an inlet (15) and a tongue (13); A turbocharger according to any one of claims 9 to 12, wherein the radial extension (47) is aligned with the inlet portion (15) or the tongue portion (13).