JP2001132662A - Structure of egr rotaty pump of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce sliding resistance with a fixed casing, and to reduce abrasion by rotatably arranging a seal roller on the tip of a rotary vane in a structure of an EGR rotary pump. SOLUTION: In this EGR rotary pump, a rotary easing 3 fixed to a rotary shaft 4 is eccentrically arranged in a fixed casing 2, a rotary vane 5 is reciprocatively arranged in a groove hole 9 of the rotary casing 3, and a seal roller 7 is rotatably supported by a side plate 8 fixed to both end surfaces of the rotary vane 5. The seal roller 7 slindingly rotatably moves on an inner peripheral surface 24 of the fixed casing 2 by following rotation of the rotary vane 5. A spring 6 is arranged in the groove hole 9 of the rotary casing 3 for elastically pressing the rotary vane 7 toward the inner peripheral surface 24 of the fixed casing 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an engine EG.
The present invention relates to a structure of a rotary pump for R.

[0002]

2. Description of the Related Art Conventionally, in a diesel engine, a part of exhaust gas discharged from a combustion chamber is recirculated to the combustion chamber as EGR gas to reduce the oxygen concentration (O ₂ concentration) during combustion and reduce nitrogen oxides. development of suppressing the occurrence of (NO _X) have been actively developed. The O ₂ concentration can be reduced by sending a large amount of EGR gas into the combustion chamber, but an EGR rotary pump is required to supply a large amount of EGR gas to the combustion chamber. Also,
A diesel particulate filter that collects suspended particulate matter contained in the exhaust gas of a diesel engine requires an exhaust gas delivery pump when the filter is regenerated by burning the particulate matter collected by the filter. is there.

[0003] A vane pump in which a rotary vane rotates in a ring is known as a pump for use as described above. The vane pump requires a powerful motor to operate the vane pump due to the frictional resistance of the vane. However, the power consumption of the engine is large and the power loss is large. To prevent this, chromium and nitrogen are mainly used at the vane tip. One provided with a hard ceramic coating is known. The hard ceramic film provided on the tip of the vane in the vane pump can reduce the dynamic friction coefficient of the vane against the inner wall surface of the cam ring (for example, see JP-A-7-310).
675).

[0004]

SUMMARY OF THE INVENTION However, EGR
Rotary pumps contain a large amount of particulate matter, SO _x , NO _x, etc. in EGR gas.
Further, since the EGR gas itself is at a high temperature, conditions such as durability, corrosion resistance, wear resistance, and heat resistance are required. That is,
When the rotary vane is rotated at high speed in the fixed casing of the rotary pump for EGR, wear is generated on the wall surface of the fixed casing and the tip of the rotary vane.
EG is mixed with GR gas or is
The rotary pump for R is damaged and cannot be used. E
When lubricating oil is mixed into GR gas, H
C and the like are generated, causing environmental pollution, and if lubricating oil gas is mixed into the intake air taken into the engine or the like, the operating state is deteriorated. Therefore, it is preferable not to use lubricating oil in such a rotary pump, but if lubricating oil is not used in the rotary sliding part, the sliding surface will be worn and the durability of the rotary part will be significantly reduced. become.

Therefore, the present inventor has proposed a method in which an inner peripheral surface of a fixed casing and a rotary vane sliding on the inner peripheral surface of the fixed casing are made of porous ceramics and polyfluoroethylene or oil or fat impregnated in the porous portion. A rotary pump made of a composite material made of a hard grease such as that described above, which prevents lubricating oil from being mixed into a compressed gas body while avoiding the use of lubricating oil, was developed and filed earlier (Japanese Patent Application Laid-Open No. Hei 10-193414). No.).

Further, the present inventor has developed a system for sending a large amount of EGR gas into a combustion chamber in a diesel engine. Diesel engine equipped with the EGR device in order to suppress the generation of the NO _X is prevented knocking by thinning adjust the O ₂ concentration by performing a large amount of EGR, supplies compressed air to the combustion chamber by the turbocharger An intake port and an EGR port for supplying EGR exhaust gas to the combustion chamber are constituted by two systems.
A large amount of EGR exhaust gas is supplied from the R port to the combustion chamber,
Then injected from the fuel injection nozzle supplies compressed air to the combustion chamber from the intake port portion of the fuel into the combustion chamber to produce good premixture, thermal efficiency by preventing HC, and occurrence of NO _X (JP-A-11-13)
No. 5885).

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to provide a method for mounting a rotating vane between an inner peripheral surface of a fixed casing and an inner peripheral surface of the fixed casing. A seal roller composed of a cylindrical member is interposed to reduce the sliding resistance between the fixed casing and the rotating vane, secure a good sealing state, and prevent lubricating oil and wear debris from being mixed into the EGR gas. In addition, the engine E that can prevent the generation of HC and the like due to the combustion of the fuel.
An object of the present invention is to provide a structure of a rotary pump for GR.

According to the present invention, a fixed casing is provided on an inner wall surface of an outer case having a gas inlet and a gas outlet, and a rotation axis is offset from an axis of the fixed casing so as to be rotatable with respect to the outer case. Rotating shaft supported by
A rotating casing fixed to the rotating shaft, guided by a plurality of slots formed in the rotating casing in a radial direction and extending in a radial direction, reciprocally movable toward an inner peripheral surface of the fixed casing; A rotary vane, a pump chamber formed between the rotary vanes adjacent to the rotary casing and the fixed casing, a side plate fixed to both end surfaces of the rotary vane, and a tip portion of the rotary vane. And a seal roller rotatably supported by the side plate in contact with the inner peripheral surface of the fixed casing and arranged in a non-contact state with the grooved portion.

The sliding surface between the groove of the rotary vane and the seal roller is lubricated with a lubricant supplied in minute amounts through a porous material provided in a through hole of the rotary vane.

[0010] The structure of the EGR rotary pump has a spring disposed in the slot for elastically pressing the rotary vane toward the inner peripheral surface of the fixed casing. The other end is arranged in contact with the rotary shaft in a cut groove formed in the rotary vane.

In the structure of the EGR rotary pump, the seal roller is pressed against the inner peripheral surface of the fixed casing by centrifugal force generated in the rotary vane and the seal roller as the rotary shaft rotates. Therefore, the EGR gas compressed in the pump chamber may leak from between the outermost periphery of the seal roller and the fixed casing. The pressure is strongly pressed against the surface, and leakage of the EGR gas into the pump chamber downstream of the EGR gas is reduced.

The rotary vane includes a resin body and a heat-resistant metal layer or resin layer coated on the outer surface of the resin body. Alternatively, the rotary vane is composed of an aluminum body and an alumina layer covering a sliding portion of the aluminum body, or a steel hollow member and a bearing reinforcing material.

Alternatively, the structure of the EGR rotary pump is as follows:
A permanent magnet member is attached to a cut groove formed in the rotary vane made of a non-magnetically permeable material, and an iron piece is embedded in each of the rotary vane, the rotary shaft, and the slot of the rotary casing. Member, the iron piece,
A magnetic path is formed in the fixed casing made of a magnetically permeable material and the seal roller made of a magnetically permeable material.

In this EGR rotary pump, a seal roller is rotatably mounted at the tip of a rotary vane, and the seal roller is pressed against a fixed casing in accordance with the rotation of the rotary shaft, thereby sealing the pump chamber and simultaneously rotating the rotary vane. The frictional resistance with the fixed casing can be reduced, and the wear can be reduced. That is, since the seal roller disposed at the tip of the rotary vane slides while rotating along the inner peripheral surface of the fixed casing, its friction coefficient is, for example, μ = 0.0.
1, which can be greatly reduced as compared with the sliding friction (μ = 0.12) between conventional non-rotating iron sliding bodies. In addition, if the rotating vane is provided with a permanent magnet member and the seal roller is formed of a magnetically permeable material, the seal roller is attracted to one point of the tip of the rotating vane and becomes slidable at the attracting point, forming an extremely good sealing state. can do.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the structure of a rotary pump for EGR of an engine according to the present invention will be described below with reference to the drawings. This EGR rotary pump is preferably applied to an engine using light oil, gasoline, natural gas or the like as a fuel. 1 is a sectional view showing an embodiment of the EGR rotary pump according to the present invention, FIG. 2 is a longitudinal sectional view of the EGR rotary pump shown in FIG. 1, and FIG. 3 is a rotary vane of the EGR rotary pump shown in FIG. FIG. 4 is a perspective view, FIG. 4 is a sectional view showing the rotary vane of FIG. 3, and FIG. 5 is a sectional view showing a rotary vane part of another embodiment of the rotary pump for EGR according to the present invention.

In particular, the structure of the EGR rotary pump of the engine reduces the sliding friction between the fixed casing 2 and the rotary vane 5 to reduce the amount of abrasion on the sliding surface and to mix foreign substances into the EGR gas. In order to reduce the pressure, a seal roller 7 constituting a sliding surface is provided at the tip of the rotary vane 5.

This EGR rotary pump has a gas inlet 11
The fixed casing 2 is fixed to the inner wall surface of the outer case 1 having a mounting portion 26 forming the gas inlet 11 and a mounting portion 27 forming the gas outlet 12 located on the side opposite to the gas inlet 11 in the radial direction. The outer case 1 is formed by fixing the cylindrical portion 1B and the flat plate portions 1A at both ends thereof with bolts 28. The rotating shaft 4 is located at a position where the rotating axis is offset from the axis of the fixed casing 2.
A is rotatably supported by A via a bearing 22. The rotating casing 3 is fixed to the rotating shaft 4 so as to rotate integrally with the rotating shaft 4. The rotating casing 3 is formed with a plurality (four in FIG. 1) of slots 9 formed in the radial direction and spaced apart in the circumferential direction. The rotary vane 5 is installed so as to reciprocate with respect to the inner peripheral surface 24 of the fixed casing 2 while being guided by the slot 9. Rotating vane 5
Are elastically pressed so as to reciprocate toward the inner peripheral surface of the fixed casing 2 by the spring 6 arranged in the slot 9.

This rotary pump for EGR is particularly arranged in a non-contact state with a side plate 8 fixed to both end faces of the rotary vane 5 and a V-shaped groove 17 formed at the tip of the rotary vane 5. And the inner peripheral surface 24 of the fixed casing 2
And a seal roller 7 whose both ends are rotatably supported by the side plate 8 in contact with the side plate 8. The side plate 8 is fixed to the side end surface of the rotary vane 5 by screws 16, welding or the like. In addition, the seal roller 7
Are rotatably supported by the side plate 8 via seal roller support shafts 14 at both ends thereof. The seal roller 7 closely contacts the inner peripheral surface 24 of the fixed casing 2 by centrifugal force and the spring force of the spring 6 following the rotational movement of the rotary vane 5 reciprocating with respect to the inner peripheral surface 24 of the fixed casing 2. It slides and rotates in this state.

In this EGR rotary pump, a variable volume compression chamber or pump chamber 10 is formed in a space defined between the rotary casing 3 and the fixed casing 2 and between the rotary vanes 5 adjacent to each other. Have been. Pump room 1
0 is large due to the eccentric arrangement of the rotary casing 3 with respect to the fixed casing 2 and the volume is large on the gas inlet 11 side.
The gas outlet 12 side is formed small. Further, the fixed casing 2 is formed with a slightly cut-out relief portion (not shown) in the region between the gas inlet 11 and the gas outlet 12 to enable the sliding of the rotary vane 5 smoothly. The EGR gas is smoothly introduced from the gas inlet 11 into the pump chamber 10, and the compressed EGR gas is sent out from the pump chamber 10 to the gas outlet 12. That is, in this EGR rotary pump, since the fixed casing 2 and the rotary casing 3 are eccentric to each other, the EGR sucked into the pump chamber 10 from the gas inlet 11
The gas is compressed with the rotation of the rotating shaft 4 and the gas outlet 1
Sent from 2.

In this EGR rotary pump, the sliding surface between the groove 17 of the rotary vane 5 and the seal roller 7 is formed by the groove 17
Is formed in a V-shaped groove, so that the contact between the seal roller 7 and the groove 17 forms a line contact. Also,
The seal roller 7 has a through hole 23 formed in the rotary vane 5.
Are lubricated by a lubricant supplied in small amounts through the porous material 15 provided on the V-shaped groove, and slide and rotate with low resistance to the groove portion 17 of the V-shaped groove and the inner peripheral surface 24 of the fixed casing 2. The lubricant impregnated in the porous portion of the porous material 15 is as follows.
For example, it is made of oils and fats such as hard grease which is hardened at 100 ° C. or lower. The porous material 15 is made of, for example, silicon carbide, silicon nitride, and alumina.

One end of the spring 6 is inserted into the cut groove 13 formed in the rotary vane 5, and the other end is formed on the outer peripheral surface 25 of the rotary shaft 4.
It is arranged in contact with. The rotary vane 5 follows the rotation of the rotary shaft 4 and the rotary vane 5 and the seal roller 7.
The seal roller 7 is pressed against the inner peripheral surface 24 of the fixed casing 2 by the centrifugal force generated at the time, and the sealing performance is improved.

The rotary vane 5 can be formed, for example, in a structure in which a resin main body and the outside of the resin main body are covered with a heat-resistant metal layer or a heat-resistant resin layer such as polyethylene fluoride. . Alternatively, the rotary vane 5 can be formed in a structure in which an aluminum body and a sliding portion of the aluminum body are aluminized and covered with an alumina layer. The rotary vane 5 can also be formed by a steel hollow member and a bearing reinforcing material.

Next, another embodiment of the structure of the rotary pump for EGR of the engine according to the present invention will be described with reference to FIG. In this embodiment, the sealing performance between the seal roller 7 and the rotary vane 5 is improved by using the permanent magnet member 20. This EGR rotary pump has a rotary vane 5
Is formed of a non-magnetically permeable material, and a permanent magnet member 20 is mounted in a cut groove 13 formed in the rotary vane 5. In this embodiment, the rotating vane 5 has an iron piece 1 extending in the radial direction.
8, an iron piece 21 extending to the outer peripheral surface 25 is embedded in the rotating shaft 4, and an iron piece 19 is embedded in the slot 9 in the rotating casing 3. The sliding surface between the groove 17 of the rotary vane 5 and the seal roller 7 is formed by forming the groove 17 into a V-shaped groove so that the contact between the seal roller 7 and the groove 17 is attracted by the magnetic force of the permanent magnet member 20. Line contact is reliably formed in the longitudinal direction, and the sealing performance can be improved.

The rotary pump for EGR has the above configuration, and the permanent magnet member 20 in the cut groove 13 of the rotary vane 5 → the iron piece 18 in the rotary vane 5 → the seal roller 7 of the magnetically permeable material → the fixing of the magnetically permeable material Casing 2 → adjacent seal roller 7 → iron piece 18 in adjacent rotary vane 5 → adjacent permanent magnet member 20 → iron piece 1 in adjacent rotary vane 5
8 → Iron piece 19 of adjacent slot 9 of rotating casing 3 → Iron piece 21 extending to outer peripheral surface 25 of rotating shaft 4 → Iron piece 19 of adjacent slot 9 of rotating casing 3 → First iron piece 18 in rotating vane 5 A magnetic path will be formed. Therefore, the EGR rotary pump is provided with a contact force between the seal roller 7 and the fixed casing 2 and a seal roller 7 and the rotary vane 5.
The contact force of the seal roller 7 with the groove 17 is increased, and the friction and wear are reduced by the smooth rotational sliding of the seal roller 7.

[0025]

The structure of the rotary pump for EGR of an engine according to the present invention is constructed as described above, so that a smooth rotary vane is provided by a seal roller rotatably disposed between the rotary vane and the fixed casing. , Rotation can be secured, the coefficient of friction can be reduced, the amount of wear can be reduced, and lubricating oil can be prevented from being mixed into the compressed gas, so that durability can be improved. Therefore, in an engine incorporating this rotary pump for EGR, a large amount of EGR gas whose pressure has been increased to some extent by the rotary pump can be supplied to the combustion chamber, and the combustion in which the O ₂ concentration has been reduced due to the presence of the large amount of EGR gas progresses. NO
_{The generation of X} , HC, etc. can be reduced, and the thermal efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an EGR rotary pump according to the present invention.

FIG. 2 is a longitudinal sectional view of the EGR rotary pump of FIG. 1;

FIG. 3 is a perspective view showing a rotary vane of the rotary pump for EGR of FIG. 1;

FIG. 4 is a sectional view showing the rotary vane of FIG. 3;

FIG. 5 is a sectional view showing a rotary vane portion of another embodiment of the EGR rotary pump according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer case 2 Fixed casing 3 Rotating casing 4 Rotating shaft 5 Rotating vane 6 Spring 7 Seal roller 8 Side plate 9 Slot hole 10 Pump chamber 11 Gas inlet 12 Gas outlet 13 Cut groove 14 Seal roller support shaft 15 Porous material 16 Screw 17 Groove (V groove) 18, 19, 21 Iron piece 20 Permanent magnet member 23 Through hole 24 Inner peripheral surface 25 Outer peripheral surface

Claims (7)

[Claims] 1. A fixed casing disposed on an inner wall surface of an outer case having a gas inlet and a gas outlet, and a rotation axis is offset from an axis of the fixed casing so as to be rotatable with respect to the outer case. Guided by the rotating shaft, the rotating casing fixed to the rotating shaft, and a plurality of slots formed in the rotating casing in a radial direction extending radially toward the inner peripheral surface of the fixed casing. Rotary vane reciprocally movable, a pump chamber formed between the rotary vanes adjacent between the rotary casing and the fixed casing, a side plate fixed to both end surfaces of the rotary vane, and a rotary vane. A seat which is arranged in a non-contact state with a groove formed at a tip end portion and is rotatably supported by the side plate in contact with the inner peripheral surface of the fixed casing. EG of the engine consisting of
Structure of rotary pump for R. 2. A sliding surface between the groove of the rotary vane and the seal roller is lubricated by a lubricant supplied in minute amounts through a porous material provided in a through hole of the rotary vane. Item 1. EGR of the engine according to item 1.
Of rotary pump for use. 3. A spring disposed in the slot for elastically pressing the rotating vane toward the inner peripheral surface of the fixed casing, wherein one end of the spring is formed in the rotating vane. 2. The structure of a rotary pump for EGR of an engine according to claim 1, wherein the other end of the cut groove is disposed in contact with the rotary shaft. 4. The seal roller according to claim 1, wherein the seal roller is pressed against the inner peripheral surface of the fixed casing by centrifugal force generated on the rotary vane and the seal roller as the rotary shaft rotates. Engine EG
Structure of rotary pump for R. 5. The EGR for an engine according to claim 1, wherein the rotary vane comprises a resin body and a heat-resistant metal layer or a resin layer coated on an outer surface of the resin body. Rotary pump structure. 6. The rotary vane according to claim 1, wherein the rotary vane is composed of an aluminum main body, an alumina layer covering a sliding portion of the aluminum main body, or a hollow steel member and a bearing reinforcing material. The structure of the rotary pump for EGR of the engine according to the above. 7. A permanent magnet member is attached to a cut groove formed in said rotary vane formed of a non-magnetic material,
Iron pieces are respectively buried in the rotary vane, the rotary shaft and the slot of the rotary casing, and a magnetic path is formed in the permanent magnet member, the iron piece, the fixed casing made of a magnetically permeable material, and the seal roller made of a magnetically permeable material. The structure of the rotary pump for EGR of the engine according to claim 1, wherein