JPH0531222Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable displacement supercharger.

[Conventional technology]

A supercharger is provided to improve the thermal efficiency of various types of prime movers.

This supercharger uses exhaust gas from the prime mover as its power source, and the exhaust gas flow rate varies depending on the load condition of the prime mover.

An example of a type that changes the angle of the nozzle blade is shown in FIG.

The figure shows the turbine part of the supercharger.
The casing of the turbine section is composed of a turbine casing a, a gas outlet cover b, and a shroud c.

The nozzle drive shaft d is connected to the shroud c via the bearing e.
The turbine casing a and the turbine impeller f are arranged rotatably on the turbine casing a side of the nozzle drive shaft d.
A nozzle blade g is arranged in the gas flow path connecting the two, and a nozzle link h is attached to the end of the nozzle drive shaft d on the side of the gas outlet cover b.

A tortoise-shaped space i is formed between the gas outlet cover b and the shroud c, and in this space i, in addition to the nozzle link h, a nozzle drive ring j is positioned and rotatable by the tip of the nozzle link h. It will be stored.

A drive lever m is connected to the nozzle drive ring j via a ring drive shaft k. When the drive lever m is rotated by an external drive source around the axis of the turbine wheel by the drive source of the turbine wheel, the nozzle drive ring j is rotated via the ring drive shaft k, Through the nozzle link h, each nozzle blade g is
The angle changes all at once.

Furthermore, another known example is Japanese Patent Publication No. 38-12852, which has an inflow side vane fixed to a fixed ring corresponding to the turbine casing, and an inner ring fixed to the inner circumference of the fixed ring. Outflow side vanes, and the inner ring is rotated forward or backward to change the overlapping side of the inflow side vanes and the outflow side vanes, thereby minimizing or maximizing the cross section of the gas flow path. It is a gas turbine.

[Problem that the invention attempts to solve]

In the type of supercharger that changes the angle of the nozzle blade, a supercharger having a variable capacity turbine must determine the optimum nozzle angle under the flow of high-temperature exhaust gas and must be driven smoothly.

However, it could not withstand this heat cycle,
The variable mechanism may seize or become stuck,
There is a problem that it stops driving.

In addition, in order to prevent seizure, the gap between the variable nozzle and the hub side and shroud side casings is increased to deal with this problem, but this gap significantly reduces turbine efficiency in the small flow rate range. There is a problem in that it causes a decrease in torque.

Furthermore, engine exhaust gas has high temperature and periodic pressure fluctuations. The outside of the nozzle disposed on the tongue of the turbine casing, which is located first after entering the turbine, is exposed to exhaust gas having a high temperature and large pressure fluctuations. However, the temperature of the exhaust gas that has gone around the turbine in the scroll has become lower and the pressure fluctuations have become smaller.
The exhaust gas will hit the inside of the nozzle. Therefore, the nozzle disposed in this tongue part is subjected to the harshest conditions compared to the other parts, and is prone to chattering and is often damaged as a result.

Next, regarding the product described in Japanese Patent Publication No. 38-12852, continuous control is not possible since the cross section is controlled only at two positions, the maximum and minimum, and there are two positions in total, one each on the inflow side and the outflow side. 1 blade with variable nozzle angle
Furthermore, due to thermal deformation of the blades, the overlapped surfaces of the blades on the inflow and outflow sides do not come into close contact with each other, resulting in the overlapping part on the gas flow side becoming uneven or curled up. .

[Purpose of invention]

The present invention was devised to solve the above-mentioned conventional problems, and the purpose of the present invention is to appropriately arrange fixed nozzles and variable nozzles on the same circumference, sufficiently withstand heat cycles, It is an object of the present invention to provide a variable displacement supercharger of a variable nozzle angle type that does not cause seizure and does not reduce turbine efficiency even in a small flow rate range.

[Means for solving problems]

The present invention comprises a turbine casing having a scroll surrounding the turbine wheel, and a space between the rotating tip of the turbine wheel provided at the rotation center of the turbine casing and the scroll, which is opposed to the rotating tip of the turbine wheel. A plurality of movable nozzles and fixed nozzles are arranged at equal intervals on the same circumference centered on the center of the turbine wheel between the hub side casing and the shroud side casing. The nozzle drive shaft has one end fixed at an intermediate position between the ring edge and the other end connected to a drive means into which driving force is input from the outside, so that the angle can be continuously changed all at once by the drive means. Three or more fixed nozzles are arranged at equal intervals on the circumference, and the angle that the fixed nozzles make with the tangential direction to the outer circumference of the turbine wheel varies depending on the angle that the variable nozzle makes with the tangential direction to the outer circumference of the turbine wheel. substantially identical to the smallest of the ranges, one of the fixed nozzles is characterized in that its leading edge is located downstream and immediately adjacent to the turbine casing tongue.

[Effect]

Generally, when the exhaust flow rate of a supercharger is large, turbine efficiency is not a problem, but when the exhaust flow rate is low, high turbine efficiency is required. Therefore, variable displacement superchargers with variable nozzles have been put into practical use in order to throttle the exhaust gas when the exhaust flow rate is low to increase the flow velocity and improve turbine efficiency. In the present invention, in order to prevent the variable nozzle from burning out due to thermal deformation of the casing, three or more fixed nozzles are arranged between the variable nozzles at equal intervals in the circumferential direction to minimize the deformation of the casing. Also,
Since the angle is the same as the closed state of the variable nozzle,
Even when the exhaust flow rate is low and the angle of the variable nozzle is close to closed, the flow velocity is high and the turbine efficiency is high.

Furthermore, since one of the fixed nozzles is located near the turbine casing tongue, which is exposed to the most severe conditions, the effect of preventing damage is significantly greater than when a variable nozzle is located at this location.

〔Example〕

A preferred embodiment of the present invention will be described below based on the drawings.

Fig. 1 is a nozzle arrangement diagram in the turbine casing of the present invention, Fig. 2 is a sectional view of Fig. 1, Fig. 3 is a detailed view of the main part of the fixed nozzle, and Fig. 4 is a detailed view of the main part of the variable nozzle. be.

As shown in FIGS. 1 and 2, the shroud side casing 7 and the gas outlet cover 8 are sequentially fitted into the turbine casing 5, and the scroll 18 is formed by the turbine casing 5, the gas outlet cover 8, and the shroud side casing 7. A turbine casing 1 is configured.

Further, the turbine impeller 10 is rotatably loosely fitted into the rotation center of the turbine casing 5.
A fixed nozzle 3 and a variable nozzle 4 are provided on the same circumference of the turbine casing 1 between the outer circumferential tip and the scroll 18 and opposing the outer circumferential tip.

In FIG. 1, the variable nozzle 4 is fully open at the position indicated by the solid line, where the distance between the variable nozzle 4 and the adjacent nozzle is maximum, and the amount of exhaust gas flowing into the turbine casing 5 is maximum. The position indicated by the dotted line is the closed state, and the outside of the trailing edge of the front nozzle of the adjacent nozzle is in contact with the inside of the leading edge of the rear nozzle, and the exhaust gas is in the turbine casing 5.
The amount of inflow to is minimized.

Three fixed nozzles 3 are provided at equal intervals on the same circumference, and one of them is positioned so that the leading edge 3a of the nozzle 3, which is first hit by the exhaust gas flowing into the turbine, is located close to the tongue 2 of the turbine casing. It is arranged to do so.

As shown in FIG. 2, the variable nozzle 4 is configured to be operated by a driving force inputted from the outside by a driving means 11. This drive means 11 is fitted into a donut-shaped space 9 constituted by a turbine casing 5 and a gas outlet cover 8, and the variable nozzle 4 is attached to a nozzle drive shaft at an intermediate position between its leading edge 4a and trailing edge 4b. It is fixed to one end of 13. This nozzle drive shaft 13 is connected to the shroud side casing 7 via the nozzle drive bearing 12.
It is rotatably provided through the. The other end of the nozzle drive shaft 13 is fixed to a drive nozzle link 14 on the gas outlet cover 8 side end, and the tip of this drive nozzle link 14 engages with a groove provided on the inner circumferential side of the drive ring 15. ing. This drive ring 15 is connected to a drive lever 16 on the outside of the gas outlet cover 8.

Further, as shown in FIG. 3, the fixed nozzle 3 is fixedly installed between the hub-side casing 6 and the shroud-side casing 7 at a position opposing the outer circumference of the turbine wheel 10.

Note that a gap 17 is provided between the variable nozzle 4 and the hub side casing 6.

Next, the operation of the present invention configured as described above will be described.

The flow rate of the exhaust gas, which is the power source, varies depending on the load condition of the prime mover, but in order to prevent torque from decreasing in a small flow rate range, the variable nozzle 4 is rotated to control the flow rate and inflow angle of the exhaust gas.

That is, the drive lever 16 is operated according to the change in the exhaust gas flow rate, and the nozzle drive shaft 13 is rotated from the drive lever 16 via the drive ring 15.
By rotating the variable nozzles 4 all at once to a required angle, the exhaust gas flow velocity and the angle at which the exhaust gas hits the turbine wheel can be controlled.

Further, since the angle of the fixed nozzle is fixed to the same angle as the closed state of the variable nozzle, the exhaust gas flow rate is high when the exhaust gas flow rate is low, and the turbine efficiency is good.

In addition, even under high-temperature gas, the fixed nozzle is fixed at an equal angle in order to keep the distance constant so that the hub side casing and shroud side casing will not thermally deform and the distance between them will change and the variable nozzle will not be able to move. It is set at intervals. The reason why a fixed nozzle is used as the distance maintaining means instead of a round bar is to avoid disturbing the gas flow.

In addition, the nozzle closest to the downstream side of the turbine casing tongue was fixed to the exhaust gas inlet side A,
There is a large temperature and pressure difference between the nozzle and the opposite side B, which has gone around the nozzle completely, and there is a time delay in pressure fluctuations, creating the most severe conditions for the nozzle. If a variable nozzle is used here, chattering and seizure are likely to occur. This is to prevent this from happening. Furthermore, the reason why three or more fixed nozzles are provided at equal intervals is to keep the distance between the bubble side casing and the shroud side casing constant over the entire circumference.

[Effect of idea]

As described above, the variable displacement supercharger of the present invention exhibits various excellent effects as described below.

(1) By combining fixed nozzles and variable nozzles and arranging them at required intervals, it is possible to prevent a decrease in turbine efficiency in a small flow rate range.

(2) Even if the distance between the variable nozzle and the hub side and shroud side casings is made sufficiently small, control can be achieved in a small flow rate range and seizure will not occur.

[Brief description of the drawings]

Fig. 1 is a nozzle arrangement diagram in the turbine casing of the present invention, Fig. 2 is a sectional view of the supercharger of the present invention, Fig. 3 is a detailed view of the main part of the fixed nozzle, and Fig. 4 is the main part of the variable nozzle. A detailed view, FIG. 5, is a sectional view of a conventional supercharger. In the figure, 1... Turbine casing, 2... Turbine casing tongue, 3... Fixed nozzle, 4...
Variable nozzle, 3a, 4a...leading edge, 3b, 4b...trailing edge, 5...
Turbine compartment, 6... Hub side casing, 7...
Shroud side casing, 8... Gas outlet cover, 9... Space, 10... Turbine impeller, 11...
...Driving means, 12... Nozzle drive bearing, 13...
Nozzle drive shaft, 14... Drive nozzle link, 1
5... Drive ring, 16... Drive lever, 17...
. . . 18... Scroll, A... Exhaust gas inflow side, B... Opposite side to the exhaust gas inflow side.

Claims (1)

[Scope of utility model registration request] A turbine casing includes a scroll surrounding the turbine wheel, and a hub-side casing is provided between the rotating tip of the turbine wheel provided at the rotation center of the turbine casing and the scroll, opposing the rotating tip of the turbine wheel. A plurality of movable nozzles and fixed nozzles are arranged at equal intervals on the same circumference centered on the center of the turbine wheel between the housing and the shroud side casing, and the movable nozzles have a leading edge and a trailing edge. The nozzle drive shaft has one end fixed at an intermediate position and the other end connected to a drive means into which driving force is input from the outside, so that the angle can be continuously changed all at once by the drive means. Three or more fixed nozzles are arranged at equal intervals on the circumference, and the angle that the fixed nozzles make with the tangential direction to the outer circumference of the turbine wheel is determined by the minimum variation range of the angle that the variable nozzle makes with the tangential direction to the outer circumference of the turbine wheel. A variable displacement supercharger, characterized in that one of the fixed nozzles has a leading edge located downstream and immediately adjacent to the turbine casing tongue.