JPH037037B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a housing formed of two intersecting cylindrical outer cylinder running surfaces and two side walls, and the side walls are connected to each other by shafts rotating at the same speed in opposite directions. are pierced concentrically with respect to the cylindrical running surface of the pistons, and on these axes are disposed in each case one bifoil-shaped piston, symmetrical in itself and identical to the other piston, the wings of each piston having an outer cylindrical surface. an outer contact surface running along the cylinder running surface; a cylindrical inner contact surface running along the outer contact surface of the mating piston between the blades;
an external rotary piston having transition surfaces between an inner abutment surface and an outer abutment surface forming the flanks of a wing, the transition surfaces being adapted to engage the transition surfaces of a mating piston; Regarding blowers.

Such a blower, unlike the symmetrical Roots type which itself should be placed in line, forms a long surface seal against the running surface of the outer cylinder, and according to this blower the pistons roll in engagement with each other. The wedge-shaped gap formed during this process narrows, restricting the flow, and preventing an increase in drive resistance.

Although rotary piston machines of this type are described in the Austrian Patent Specification and in the German Published Application, it is not important for the present context that multi-stages are proposed. In both publications, the circling of the transition surface of the radial section from the edge of the outer abutment surface of one piston to the other piston is depicted as epicycloid, so that a complete seal is not achieved. Learn. However, gas pockets are thereby formed which are compressed before and after the corner formed by the abutment surface and the transition surface. The energy required for its compression significantly increases the power required to drive such machines, which cannot be recovered by re-expansion. This is because this gas pocket will be opened again upon further rotation.

However, in addition, when this gas pocket opens and closes, the flow is restricted and considerable energy is consumed.

The problem of the present invention is to solve the problem in the machine mentioned at the beginning.
The purpose is to avoid the creation of such compressed gas pockets and to avoid flow restriction when the transition surfaces engage each other.

To solve this problem, the invention provides that the inner abutment surface extends in radial section over a partial circle of 90° and transitions into a flat inner transition surface at right angles to the tangent to this partial circle. The inner transition surface bends at an angle of 120° in the direction of the longitudinal axis of the piston at the conical part to become a flat outer transition surface, and the outer transition surface connects the outer abutment surface with the piston neck. Just cut it.

The blower according to the invention, in contrast to the known blower with a two-blade piston, has significantly lower power requirements. This is because the trapped working gas is compressed and flow restriction is avoided when the piston is engaged. For the same reason, a reduction in the production of noise, which is also very disadvantageous, is also achieved with such blowers.

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

Regarding FIG. 1: In a schematic radial section of a blower according to the invention, the blower is designated at 1, its outer cylinder running surface is designated at 2, and its one side wall, seen in plan, is designated at 3. Furthermore, axes 4 and 5 passing through the housing perpendicularly to the side wall are designated 4 and 5 on which pistons 6 and 7, mutually identical and symmetrical in themselves, rotate in opposite directions. In the area where the cylinder running surfaces intersect, an inlet opening 8 and an outlet opening 9 for the working gas are provided.

Each piston 6 and 7 has an inner abutment surface 12 and 13 between its wings 10 and 11, which abutment surfaces extend over a partial circle of 90 DEG in radial section. The inner abutment surface transitions perpendicularly to the tangent to this partial circle into an inner transition surface 14, 15, 16, 17. These transition surfaces 14, 15, 16, 1
7 is bent inwards at an angle of 120°, i.e. towards the longitudinal axis of the piston, at arcuate conical portions 19, from which outward transition surfaces 20,
21, 22, 23, and finally the outer contact surface 2
4, 25, the outer abutment surface describes a partial circle of 50° in radial section. The cone 19 results from the epicycloid described by the cone of the mating piston when rolling. However, the cone can be replaced by a so-called circular curve in order to simplify the factory production without any difficulties, especially taking into account the sealing gap.

The radial extension of the inner transition surfaces 4, 15, 16, 17 and the beginning of the cone 19 result from the piston position shown in FIG. 4, in which the longitudinal axis 18 of the pistons 6 and 7 is at an angle of 45° to the long axis of the housing 1. In this position,
The inner transition surfaces 17 of both pistons 6 and 7 lie in one plane and their outer corners then abut, apart from the sealing gap between the pistons. On the other hand, the position of the outer corner angle of the cone 19 and thus of the inner corner of the outer transition surfaces 20, 21, 22, 23 results from the position of the piston shown in FIG. In this position, the upper piston 6 is formed by the outer transition surface 23 and the outer abutment surface 25 of the upper piston 6.
The corner 27 engages the inner abutment surface 13 of the lower piston 7. The outer corner angle of the cone 19 then faces the outer corner angle of the transition surface 17 of the lower piston 7.

Therefore, the cone portions 19 of both pistons 6 and 7 slide relative to each other from the piston position shown in FIG.
The corner 28 of the lower piston 7 formed by the outer transition surface 23 and the inner abutment surface 13 of the upper piston 6
move away from This rolling process is caused by the upper piston 6
1 when the outer abutment surface 25 of the piston 7 engages the inner abutment surface 13 of the lower piston 7. That is, the seal between both pistons 6 and 7 is
From the position of FIG. 2 of the position of the abutment surfaces 13 and 24, the rounded portion 1 is moved until the next abutment surfaces 13 and 25 are engaged again.
9 will accept.

The formation of the piston sides described here is radially symmetrical and the same on all four sides of the vanes of each piston. The side wheels are offset inwardly by a small amount with respect to the cylinder running surface 2 and with respect to the mating piston in order to enable contact-free running with the narrowest sealing distances.

At the radially outer ends of the inner transition surfaces 14, 15, 16, 17, there is provided a concave portion 29 extending over the entire axial length; 17 is facing one of the outer transition surfaces 20, 21, 22, 23 to facilitate the flow of the working medium away.

In the case of the blower described above, eight passages of inner transition surfaces 14, 15, 16, 17 and outer transition surfaces 20, 21, 22, 23 occur during each rotation of shafts 4 and 5, starting at the position shown in FIG. Sometimes the transition surfaces meet and run away in the following order: i.e. 17 becomes 23, 23 becomes 17, 21 becomes 16 and 15
becomes 22, and repeats 14 becomes 20, 2
0 runs off adjacent to 14, 22 to 15 and 16 to 21, in each case the second reference numeral being that of the lower piston. Therefore, here, the blade 11 of the upper piston 6 first
It passes along the right side of the lower piston 7 in the position shown, and then the vanes 10 of the upper piston 6 pass along the other side of the piston 6.

In the position of FIG. 2, the inner transition surface 17 of the upper piston 6 approaches the outer transition surface 23 of the lower piston 7 to the extent that both surfaces are parallel. The flow of the working gas present between these surfaces towards the pressure side and away around the cone 19 is improved by the indentation 29 of the transition surface 17 of the upper piston.
In this parallel position, a relatively wide gap remains between the pistons, which on further rotation expands into a triangular chamber in the cross-section shown (FIG. 3) and which connects the piston neck 28 of the lower piston 7. As soon as it leaves the inner abutment surface 13 of the upper piston 6, it opens towards the suction chamber (FIG. 4). During the intervening suction phase of the working gas, the surrounding chamber is therefore expanded rather than narrowed. Next, the transition surface 17 mentioned above
As the conical portion 19 adjacent to the corners 27 and 23 finishes rolling, the corner 27 of the upper piston 6 as shown in FIG.
engages the inner abutment surface 13 of the lower piston 7, a further chamber, triangular in radial section, is momentarily formed between the outer transition surface 23 of the upper piston 6 and the inner transition surface 17 of the lower piston 7. close. When this triangular chamber rotates further, it opens again toward the suction side while forming a relatively wide space.
However, as it rotates further, it expands outward,
From there, the working gas is forced out through the outer abutment surface 23 of the lower piston 7. Further rotation then transition surfaces 16 and 2 of the lower piston 7
When the passage of the transition surfaces 21 and 15 of the upper piston 6 along 2 takes place mirror-symmetrically to the previously described process, and the wing 10 of the upper piston 6 passes to the left in FIG. 1 of the lower piston 7. Both processes are repeated.

It thus becomes clear that in this passing phase of the transition surface, the gas pockets formed between the pistons rolling next to each other cannot become narrowed and contain the gas. When the piston necks, e.g. 28, 30, of the lower piston 7 are inserted into the space between the inner transition surfaces 17, 16 of the upper piston 6 and the inner abutment surface 13, the movement of the transition surfaces toward the parallel position occurs in the short term. Only the working gas will flow smoothly and immediately spread into the triangular chamber.
Similarly, as soon as the piston neck is released, a change occurs in which parallel space expands into expanded space.

[Brief explanation of the drawing]

1 to 5 are schematic radial cross-sectional views of the blower according to the invention in various sequential positions. 2... Outer cylinder running surface, 3... Side wall, 4, 5...
Shaft, 6, 7... Piston, 12, 13... Inner contact surface, 14, 15, 16, 17... Inner transition surface,
19... Rounded part, 20, 21, 22, 23... Outer transition surface, 24, 25... Outer contact surface, 27, 2
8,30...piston neck.

Claims (1)

[Claims] 1. A housing having two intersecting cylindrical outer cylinder running surfaces and two side walls, the side walls of which are connected to both outer cylinder running surfaces by shafts rotating at the same speed in opposite directions. These axes are pierced concentrically with respect to the planes, and on these axes are arranged in each case a two-winged piston, symmetrical in itself and identical to the other piston, the wings of each piston having an outer cylinder running surface. a cylindrical inner abutment surface that runs along the outer abutment surface of the mating piston between the wings, and an inner abutment surface and an outer abutment surface that form the sides of the wing. In an external rotary piston blower having transition surfaces between the pistons and the transition surfaces meshing with the transition surfaces of the mating piston, the inner abutment surfaces 12 and 13 have an angle of 90° in radial cross section. It extends over a partial circle and transitions at right angles to the tangent to this partial circle into a flat inner transition surface 14, 15, 16, 17, which in the rounded part 19 is connected to the piston 6, 7 into a flat outer transition surface 20, 21, 22, 23 which connects the outer abutment surface 24, 25 to the piston neck 27, 28, An external shaft rotary piston blower characterized by cutting at 30 degrees. 2 Inner transition surface 14, 1 of one piston 6, 7
The radially outer corners of 5, 16, 17 are connected to these inner transition surfaces 16 or 17 of one piston 6, 7.
contacts at a position of the piston 6, 7 lying in one plane with the inner transition surface 17 or 15 of the other piston,
An external rotary piston blower according to claim 1. 3. Claim 1 or 2, wherein the rounded portion 19 is a rolling curve of the rounded portion 19 of the mating piston.
External shaft type rotary piston blower described in . 4. The inner transition surfaces 14, 15, 16, 17 are provided with indentations 29 near their radially outer edges, which extend over the entire axial length of these transition surfaces. The external shaft rotary piston blower according to item 1.