JPH06200885A - Displacement type machine operated by vortex flow principle - Google Patents

Abstract

PURPOSE: To well guide a seal strip in longitudinal direction and to reduce friction generation by at least partially forming a snake-like portion in a groove receiving the seal strip that seals a displacement element in tangential direction. CONSTITUTION: Plural strips 3a, 3b respectively spirally extending separated 180 degree from each other are arranged as displacement elements in both sides of plate 2 in a rotor 1. And, a boss 4 or a penetrating window 6 for purpose of installation is arranged in the plate 2. Furthermore, grooves 30 in which a seal strip is mounted are formed in each plates 3a, 3b. In this invention, the grooves are at least partially formed as snake-like shape. However, the snake-like portions of the grooves 30 are limited in the region extending over about 150 degree of inner side from delivery direction of each strip 3a, 3b. By this manner, the seal strips are well guided in longitudinal direction, and friction generation is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive displacement machine for a compressible medium, which has at least one spiral-shaped discharge chamber arranged in a stationary casing and disposed in the discharge chamber. It has a spiral-shaped displacement member, which causes a circular motion limited by the peripheral wall of the discharge chamber at each point during operation on a plate-shaped rotor that can be driven eccentrically with respect to the casing. Is held, and the curvature of the displacement member is relative to the discharge chamber,
It is specified that the inner and outer peripheral walls of the discharge chamber and the seal line that continuously moves during operation are brought into contact with each other, and the end surface of the displacement member adjacent to one side wall of the discharge chamber is provided with a groove, A seal strip made of an elastic and slidable material is mounted in the groove.

[0002]

2. Description of the Prior Art A spiral displacement positive displacement machine is known from German patent application DE-A-2603462. A compressor of such a construction provides a virtually pulsating discharge of a gaseous working medium, for example air or an air / fuel mixture, and is therefore used especially for supercharging internal combustion engines. In the operation of such a compressor, a plurality of substantially sickle-shaped work chambers are formed so as to be enclosed along a displacement chamber between two peripheral walls of a displacement member having a spiral shape. To the exit through the pushing room. The working chamber then gradually reduces in volume and correspondingly increases the working medium pressure.
In this case, the seal between the working chambers above and below the displacement member is of great importance.

A displacement machine of the type mentioned at the outset is known from US Pat. No. 3,994,636. In order to achieve an effective radial seal between the end face of the displacement member and the side wall of the discharge chamber, an effective axial contact between both members must be made. For this purpose, the displacement member is provided with a groove on the end face, which groove receives the sealing strip. The sealing strip is made of a resilient, slidable material and is configured to be axially and slightly radially moveable within the groove. The seal strip has a spring member disposed on the lower side.

The groove for receiving the sealing strip is adapted to provide a satisfactory lateral guidance of the sealing strip mounted in the groove. The positioning of the sealing strip in the longitudinal direction of the groove is carried out by the ends of the spiral wall of the groove formed. With such a positioning, the sealing strip mounted in the casing is sufficient for the loads that occur during operation and the sealing strip is retained. In the sealing strip mounted in the groove formed in the end face of the spiral strip of the displacement member, an acceleration force is generated during operation, which acceleration force is caused by the circular movement of the displacement member. Such a load has a direction of action which swivels with respect to the sealing strip, ie the inertial forces swivel with respect to the sealing strip in the plane of the grooves of the sealing strip rather than in one direction to the sealing strip. Acts like. Correspondingly, the reaction force on the sealing strip also changes direction.
The lateral component of the reaction force is perfectly received by the lateral walls of the groove, while the longitudinal component of the reaction force causes the sealing strip to move forward and backward in the groove, where the ends of the groove are To form a stopper for such relative movement.

At high operating speeds, the reaction forces increase, and the longitudinal guidance of the sealing strip according to the known art is not sufficient for the reaction forces generated. The constantly redirecting longitudinal component of the reaction force generated in the sealing strip causes a reciprocating movement of the sealing strip in the groove, which increases the wear of the sealing strip or the walls of the groove.

[0006]

SUMMARY OF THE INVENTION The object of the invention is to improve the groove of the sealing strip in a rotary piston positive displacement machine of the type mentioned at the outset, to better guide the sealing strip in the longitudinal direction and to reduce the occurrence of wear. Is to

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the invention provides a groove for receiving a sealing strip, which is necessary for sealing the displacement member in the axial direction, at least partially having a serpentine profile. ing.

[0008]

Advantages of the Invention The advantages of the present invention are the effectiveness of the groove shape and ease of fabrication. The effectiveness is that the sealing strip is produced as an essentially straight component, and after the mounting of the sealing strip, the elasticity of the sealing strip causes a holding action in the longitudinal direction of the groove of the sealing strip.

Advantageously, the groove of the sealing strip has a serpentine profile only at the end on the outlet side. This keeps the required radial space within limits.

[0010]

First, the mechanical structure and process course required for understanding the function of a positive displacement machine (compressor) will be briefly described.

On both sides of the plate 2, two strips 3a, which are offset from each other by 180 ° and extend spirally, are formed.
3b are arranged and the strips are held perpendicular to the plate 2. The spiral itself is composed of a plurality of arcs that connect to each other in the illustrated embodiment. The plate 2 is mounted on the eccentric plate 23 via the rolling bearing 22 by the boss 4.
Is attached to. The eccentric plate is a component of the main shaft 24. An eye 5 is arranged on the outer side of the strips 3a and 3b in the radial direction, and this eye receives the guide bearing portion 25, and the guide bearing portion is fitted to the eccentric pin 26. The eccentric pin is a component of the guide shaft 27. In the region of the spiral end, the plate is provided with four through-windows 6 through which the medium can reach from one plate side to the other plate side and is therefore arranged only on one side. It is made to flow out from the central outlet 13 which does not exist.

Two casing halves 7a,
7b. Two discharge chambers 11a, 11b arranged 180 ° apart from each other are machined as spiral slits by forming webs 45, 46 in both casing halves. The discharge chamber formed of a slit extends from each inlet 12a, 12b arranged on the outer periphery of the spiral in the casing to one common outlet 13 provided inside the casing. The discharge chamber has substantially parallel cylindrical walls arranged at equal intervals, and the cylindrical walls form a spiral of 360 ° like the displacement members (3a, 3b) of the plate 2. . Displacement members (3a, 3b) are engaged between the cylindrical walls, the curvature of the displacement members being defined such that the strip approximately contacts the inner and outer cylindrical walls of the casing at a plurality, eg at two points. ing. A sealing strip 9 is mounted in a groove 30 formed in the free end faces of the strips 3a, 3b and the webs 45, 46, by means of which the working chamber is against the end wall of the casing or the plate 2 of the displacement member. Will be sealed.

Two eccentric devices (23, 24 or 26, 27) drive and guide the positive displacement machine. The main shaft is supported in the rolling bearing 17 and the slide bearing 18.
The main shaft is provided with a V-belt wheel 19 for driving at an end portion protruding from the casing half portion 7a. A counterweight 20 is arranged on the main shaft for compensating the mass force generated when the rotor is eccentrically driven. A guide shaft 27 is supported in the casing half 7a.

In order to obtain the unequivocal guidance of the rotor at the dead center position, both eccentric devices are precisely synchronized in angle. This takes place via the toothed belt transmission 16. This results in a double eccentric drive, so that every point on the displacement plate and thus every point on both strips 3a, 3b causes a circular movement. Strips 3 on the inner and outer cylindrical walls of the associated discharge chamber
Due to the alternating multiple approaches of a and 3b, a sickle-shaped working chamber is created on both sides of the strip for confining the working medium, which working chamber exits through the discharge chamber during drive of the plate 2 of the displacement member. Can be moved in the direction of. In this case, the volume of the working chamber is reduced and the pressure of the working medium is correspondingly increased.

The sealing strip 9 seals the discharge chamber with respect to the casing half. The seal strip 9 is mounted in the groove 30 formed in the end faces of the strips 3a and 3b and the webs 45 and 46.

Grooves (not shown) formed in the webs 45 and 46 of the discharge chamber extend substantially parallel to the spiral wall. The radial guidance of the sealing strip is uniquely formed by the groove wall 31. The tangential guidance is ensured by the groove ends 32 of the sealing strip as shown in FIG.

In accordance with the present invention, a groove 30 formed in the same track on the displacement member to receive the sealing strip.
Is not formed parallel to the walls of the spiral strips 3a and 3b, but is formed in a meandering shape.
The effect of such an arrangement consists in the tangential guidance or damping of the tangential movement of the sealing strip.

The groove 30 for the sealing strip is usually formed by a cutting process into the end face of the displacement member. In this case, the displacement member is rotated in the vicinity of the milling tool, causing the milling tool to carry out the radial feed movement required to obtain the spiral shape of the groove. In forming the groove according to the invention, the radial feed movement of the milling tool is additionally overlapped by a radial reciprocating movement, which is not a problem in conventional NC-controlled machine tools today.

Insertion of the sealing strip in the groove is also not a problem. The meandering track of the groove for the sealing strip has a relatively small maximum meandering distance with respect to the centerline of the groove, so that the sealing strip is inserted into the groove effortlessly.

The serpentine profile of the groove for the sealing strip is limited to the section of the spiral strips 3a, 3b in the illustrated example which extends approximately 150 ° to 180 ° inward when viewed in the transport direction.

The invention has been made on the basis of the following considerations: The serpentine course of the sealing strip requires a large radial space requirement; the spiral-shaped wall of the displacement member is constructed wide. There must be. If the spiral-shaped wall of the displacement member is widened over its entire length, the radial dimension of the spiral machine (spiral displacement machine) increases unless the discharge capacity is reduced.

Experiments have shown that the meandering shape of the groove for the sealing strip is that of the spiral strip of the displacement member,
It has been found that said groove should be provided only in the most endangered section in the prior art arrangement. The endangered section is the outlet end of the sickle-shaped working chamber. There, the gaseous working medium is compressed towards the outlet, as already mentioned, and the temperature of the working medium rises, which in turn raises the temperature of the wall limiting the working chamber.

By limiting the serpentine profile of the groove for the sealing strip to the exit area of the spiral, radial expansion of the positive displacement machine of spiral construction is avoided. This is because the widening of the spiral-shaped strip takes place only in the sections which meander the sealing strip and is directed radially inside the machine.
Furthermore, a reliable operation of the sealing strip is guaranteed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a positive displacement machine.

FIG. 2 is a plan view of a displacement member of the positive displacement machine.

FIG. 3 is a perspective view of a spiral wall / strip and attached seal strip.

[Explanation of symbols]

1 rotor, 2 plates, 3a, 3b strips, 4 bosses, 7a, 7b casing half,
9 seal strips, 11a, 11b discharge chamber,
12a, 12b inlet, 16 toothed belt transmission, 17 rolling bearing, 18 sliding bearing, 1
9 V-belt, 20 Counterweight, 22
Rolling bearing, 23 Eccentric plate, 24 Spindle, 25
Guide support, 26 eccentric pin, 27 guide shaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fritz Spinler, Meringen, Rent Ecker, Switzerland 5

Claims (2)

[Claims] 1. A displacement machine for compressible media, comprising at least one spiral discharge chamber (11a, 11) arranged in a stationary casing (7a, 7b).
b) and a spiral displacement member disposed in the discharge chamber, and the displacement member is mounted on a plate-shaped rotor (1) that can be driven eccentrically with respect to the casing It is held so as to generate a circular motion limited by the peripheral wall of the discharge chamber, and the curvature of the displacement member moves continuously with the peripheral wall inside and outside the discharge chamber with respect to the discharge chamber during operation. And the end face of the displacement member adjacent to one side wall of the discharge chamber (11a, 11b) is provided with a groove (30), and is elastic and slidable in the groove. Of the type in which a sealing strip (9) of material is fitted, the groove (3) receives the sealing strip (9) required for axial sealing of the displacement member.
Positive displacement machine operating on the vortex principle, characterized in that 0) has a serpentine profile at least in part. 2. The meandering course of the groove (30) in the sealing strip is approximately 150 ° inside the displacement member when viewed in the discharge direction.
Positive displacement machines limited to sections extending across.