JPS59136586A - Oscillating piston pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an oscillating piston pump with at least one sealing sleeve, the sealing sleeve comprising a radially extending section held at least in part by the piston portion and a cylinder wall. (Regarding a type having a lip area that fits tightly.)

In pumps or compressors of common construction, the planter piston and the connecting rod that engages with it are formed by two different parts, which are connected to each other via a piston pin. The disadvantage of this configuration is that the piston pin and the grease lubrication required for it are 71?
It is located in a hot area of Nzo. This creates problems, inter alia, regarding the service life of the grease for the lubrication of the piston pin. In addition, the aforementioned syringe piston (in this case lateral guide edges between the flange piston and the cylinder wall arise, and for this reason a suitable guide ring for the piston is generally required). Yes, this guide ring forms the friction part.

In order to avoid the aforementioned drawbacks, pumps with oscillating pistons have already been produced. In this pump, the piston and its associated connecting rod are integrally formed. Therefore, the piston moves along with the connecting rod.

In this arrangement, the pivoting movement of the piston creates a non-tightness in the central part of the edge of the piston, ie at the point G where the rocking piston is inclined with respect to the longitudinal axis of the cylinder. This German known rocking piston (for example, US Pat. No. 396
No. 1 '869) compensates for this non-tightness by providing a sealing sleeve.

However, known oscillating piston pumps of this type still have significant drawbacks. The sealing sleeve is stamped from an elastic or elastically deformable plate (often a Teflon plate). This sealing sleeve therefore has a lip area that is in close contact with the cylinder wall G and partially a piston part G.
It thus has a uniform wall thickness in the radially extending section which is retained. This sealing sleeve therefore does not have sufficient resistance to the lateral support of the rocking piston. Since the gas forces act in the direction of the crank arm, theoretically no lateral guiding forces can be generated by the gas forces on this rocking piston. However, even in this swing piston, in practice, some lateral guiding force occurs. These lateral guiding forces are due in particular to friction and inertia forces. The lack of lateral support induces premature wear in the lip area. Due to the lip area thinned by wear, there is a risk that the "lower" piston part, which is displaced "one" below the sealing sleeve, comes into contact with the cylinder wall, thereby causing damage. The term "downward" here means close to the crank casing.

The object of the invention is to provide a oscillating piston in which the aforementioned disadvantages of known pumps are avoided as much as possible with simple means and at low cost, and at the same time a strong lateral guidance for the oscillating piston can be obtained. Our goal is to provide pumps.

The gist of the present invention, which solves this problem, is to provide a piston pump of the type mentioned at the beginning. The wall thickness of the radially extending sealing sleeve portion is greater than the wall thickness of the lip region.

With this type of configuration of the oscillating piston pump or of the sealing sleeve of the oscillating piston pump,
A sufficiently strong support for the tilted rocking piston is obtained and the desired good contact of the lip area in the form of a self-sealing lip sealing element is maintained. However, it is not possible to consistently increase the wall thickness of the sealing sleeve, for example to increase the wall thickness of the radially extending sealing sleeve section. If the wall thickness of the sealing sleeve as a whole is simply increased, the wall thickness of the lip area also increases correspondingly, and if the wall thickness is too large, the adhesion to the cylinder wall is impaired.

In an advantageous embodiment of the invention, the maximum wall thickness of the lip area of the sealing sleeve is LI' 0.6 mm.

With this arrangement, the lip area adapts continuously to the cylinder wall over its stroke throughout the working process;
This avoids non-sealing. Avoidance of non-sealing properties is extremely important in pump pistons, so that pump function can be effectively maintained without compromising self-sealing properties. .

In one advantageous embodiment of the invention, the inner diameter of the pump cylinder is slightly narrower in its central region.

In this range, the oscillating piston is in its most inclined position and therefore, for a pump cylinder with a uniform internal diameter, the distance of the sealing sleeve closing between the piston pump and the cylinder wall is at its maximum, but , this interval is slightly reduced by the measures already mentioned. Furthermore, in oscillating piston pumps of the type mentioned at the outset, considerable noise is produced. Experiments have shown that the cause of noise is
During the suction stroke, air from the crank chamber passes through the lip area of the sealing sleeve and flows into the pump chamber. As a result of the air rubbing against the lip area, parts of the lip area are slightly separated from the cylinder wall and then come into contact with the cylinder wall again, which results in the noise already mentioned. Another object of the invention is therefore to obtain the quietest possible operation of the oscillating piston pump. According to an embodiment of the invention, which solves this problem, in an oscillating piston pump of the type mentioned at the outset, the sealing sleeve is arranged below the radial sleeve section, i.e. in the section with the second lip area. - The piston extends slightly in the direction of the crank chamber. This significantly avoids the flow of air from the crank chamber to the pump chamber. This allows such oscillating pistons to operate with less noise. .

A particularly advantageous embodiment of the invention is that on the flow side, the oscillating piston has a second
A sealing sleeve is provided, which second sealing sleeve is directed toward the crankcase in its lip region. In this way, a very simple construction of the rocking stone pump is obtained.

Next, the present invention will be specifically explained with reference to the illustrated embodiments.

The swinging piston pump designated by reference numeral 1 is equipped with a pump cylinder 2, and a swinging piston 3 is disposed within the pump cylinder 2.
is being guided. The swinging piston 3 is connected at its end opposite to the pump chamber 4 via a bearing 5 to an eccentric support 6 of the crankshaft. The piston part 7 of the rocking piston 3 has a support 8 and an upper removable piston part 9, etc. A seal child rib 10 is fixed between the support portion 8 and the piston portion 9.

According to the invention, relative to the longitudinal axis of the upper piston part 9, the radially extending sleeve part 11 has a greater wall thickness a than the wall thickness l of the lip region 12 of the sealing sleeve 10. ing. This creates an annular lip range 1
2 is sufficiently thin to have good contact with the cylinder wall 13 of the pump and, as can be seen from FIGS. 1 and 2,
A strongly designed lateral guide for the rocking piston 3 is obtained. The maximum wall thickness of the lip region 12 of the sealing sleeve 10 is approximately 0.6 mm. The sealing sleeve may be made of, for example, a flexible but not particularly elastic material, such as I
? When made from litertrafluoroethylene, sufficient adhesion is obtained even if the lip region 12 has a wall thickness of 0.6 mm or less.

Thus, the sealing sleeve 10 can act like a self-sealing lip seal member. For that purpose, an annular gap 14 is provided between the upper piston part 9, which has an outer diameter D1, and the inner diameter of the lip region 12.

A pressurized delivery medium enters into this annular gap 1 and brings the lip area 12 into contact with the cylinder wall in any position of the rocking piston 3.

The sealing sleeve 10 is integrally formed in the shape of a pot with a thick bottom. In that case, the bottom part forms a radially extending sleeve part 11 (see FIG. 2). Advantageously, the lip region, in its undeformed state (FIG. 2), is formed to flare laterally outwards, so that even when the delivery medium is under no pressure, the cylinder wall 1
A sufficient deformation force is obtained to bring the lip region 12 into contact with the lip region 12. The transition from the radially extending sleeve part 11 to the lip region 12 is designed in the manner of a film hinge so that it can be pivoted slightly. For this purpose, a groove is preferably formed between the radially extending sleeve part 11 and the lip region 12.

The piston part 9 is removably fastened to the remaining rocking piston part via a screw 16. As a result, the sealing sleeve l○ can be replaced from the pump chamber raw side, as is known in the art. The support δ supporting the sealing sleeve 10 from below has a diameter D2, which is slightly smaller than the diameter D1 of the upper piston part 9. by this,
When the oscillating piston slides when the sealing sleeve 1o is slightly worn, the risk of the support 8 coming into contact with the cylinder wall 13 and damaging it is avoided. in this way,
The reason why the outer diameter D2 of the support portion 8 can be made small is as follows.
This is because the radially extending sleeve portion 11 has a relatively large wall thickness. radially extending sleeve portion 1
Because the wall thickness a of lip region 12 is greater than the wall thickness a of lip region 12, the following advantages are obtained.

That is, even if the lip region 12 is partially worn, the oscillating piston 3 will still retain the radially extending sleeve portion 11.
sufficient guidance can be obtained during this time, thereby avoiding damage to the cylinder wall 13. If this sealing function is lost, the pump will no longer be able to discharge, but
In a particularly advantageous embodiment of the invention, the internal diameter D3 of the pump cylinder 2 is slightly reduced in its central region 17 (diameter D3' in FIG. 4) before causing mechanical damage to the cylinder wall 13. reference).

The effect of this means is clear when comparing FIGS. 3 and 4. FIG. 3 shows the pump cylinder very schematically. In FIG. 3 the oscillating piston 3 is shown in three different positions.

At top dead center and bottom dead center, the longitudinal axis 18 of the oscillating piston δ coincides with the longitudinal axis of the pump cylinder 2 and the diameter 1) of the upper piston part 9 and the diameter D2 of the support δ coincide with the longitudinal axis of the pump cylinder 2. If properly adapted to the inner diameter D3, the sealing sleeve 10 is tightened to the swing piston 3 and 1. I?
The radial gap between the pump cylinder 2 and the cylinder wall 13 is relatively small. On the other hand, if the rocking piston occupies a corresponding oblique position in its central position and the pump cylinder 2 has the same internal diameter D3 over its entire axial length, this gap will be relatively large. This large gap S to be closed by the sealing sleeve 10
P is reduced by the fact that the pump cylinder 2 is slightly reduced in its central region 17, as indicated by the diameter D3'. This diameter reduction is adapted to the oblique position of the rocking piston 3. The cross section of the inner diameter of the pump cylinder is circular no matter where it is cut. On the other hand, the change in the gap SP between the swinging piston 3 and the cylinder wall 3 of the pump is most significant within the pivot plane of the swinging piston.

This pivot plane corresponds to the plane of view of FIGS. 3 and 4.

In the longitudinal center plane perpendicular to the drawing plane, the gap between the swing piston 3 and the cylinder wall 13 of the pump does not increase even when the swing piston 3 is tilted. By narrowing to a relatively small inner diameter D3",
The lip region 12 is compressed slightly radially inwards in the section lying perpendicular to the plane of the drawing of FIG.

Correspondingly, the annular lip region 12 is shaped like a rocking piston 3.
In the area of the pivot plane S, it is even easier to close the slightly increased gap between the rocking piston 3 and the cylinder wall 13. Inner diameter D3 relative to inner diameter D3
The reduction in diameter of ' is shown in an exaggerated manner in FIG. 4 for clarity. This will be explained in more detail later.

The central range 17 means the central range of the piston stroke H. This stroke H is shown significantly enlarged in the drawing. Figure 5 is a view of Figure 4 viewed from above.

The displacement of the oscillating piston pump of the present invention is not only comparable to the actual displacement of the known oscillating piston, which is approximately 20 l/min to approximately 100 AK/min, but also approximately 201/m
in ~2001/min, depending on the case 5001/m
It is also possible to have extremely large discharge ranges up to in. In that case, the oscillating piston pump l acts in particular as a lubrication-free pump.

By non-lubricated pump is meant a pump in which the piston slides along the cylinder wall 13 without lubrication. The advantage of the latter is that the lubricating medium is not mixed with the delivery medium.

Liquids and gases are used as discharge media. All the features mentioned above or in the claims may be used individually or in any combination.

The oblique position of the rocking piston 3, in particular the oblique position as shown in FIG. 1, is exaggerated for clarity. The same applies to the radial spacing of the gap sp in FIGS. 3 to 5.

According to a special embodiment of the invention, when the oscillating piston δ is located obliquely in accordance with the crank angle α, an ellipse corresponding to the outer circumference in this oblique position is located at the top dead center or at the bottom dead center. approximately corresponds to the inner circumference of the pump cylinder 2 in
The inner diameter D3α of the pump cylinder 2 changes over the piston stroke H. This geometrical relationship will now be explained in detail based on FIG.

Internal diameter D3 over the piston stroke H depending on the crank angle
By configuring α as described above, the following result is obtained. That is, the lip area 12 of the sealing sleeve 10
The logical outer circumference of the oscillating piston 3 remains, at least approximately, the same size in all stroke positions of the rocking piston 3. The diameter of the pump cylinder 20 is reduced in such a way that, when the lip area passes through the central area of the piston stroke H, this lip area only needs to be deformed from the shape of the annular ring at top dead center or bottom dead center into various approximately oval shapes. varies depending on the crank or the corresponding crank angle. In that case, the outer circumference of the lip area does not actually change.

In other words, the piston stroke H depends on the crank position.
If the inner diameter D3α is selected appropriately over the piston stroke H, the lip area 12 of the sealing sleeve 10 has a circular shape with an outer circumference of a predetermined dimension at the top dead center or the bottom dead center, and this lip area has a length of its outer circumference over the piston stroke H. It is sufficient if it can be deformed into various oval shapes without changing its shape.
The circumference of this ellipse actually always has the same length as the circumference of the circle. The load on the lip area 12 of the sealing sleeve is therefore relatively low.

Therefore, relatively less elastic materials can be used as the material for the sealing sleeve 10, especially in rocking piston pumps, without causing too large a deformation of the sealing sleeve or creating any non-tightness. Large distances are possible without strain.

The symbols used in FIG. 6 and below are as follows.

l = Crank length r - Crank eccentricity α - Crank angle at top dead center β - Piston inclination angle at top dead center Projection of crank length onto the connecting line between piston center point M and crank rotation axis A = The theoretical diameter of the sealing lip corresponds to the diameter D3 of the pump cylinder 2 at top dead center and bottom dead center. In the oblique position of the rocking piston 3, the lip area has an elliptical shape with an outer circumference UE.

This outer circumference TJE can be determined by the following formula (
(See Figure 6).

sin α: Ding a = r X sin α
(Equation 2) Kino β-1, furthermore, k2212-a2 further- 瀉β=- From Equation 1: D+d=2k D=2 -d; Substituting this for Takefu, a,
-humer sin' U d ft ding fu sin' (1 The symbol d in the last equation corresponds to the minor axis of the lip range deformed into an oval shape depending on the crank angle α in FIG. 6. Thus, 1. I? By making the inner diameter D3α of the pump cylinder dependent on the crank angle α over the piston and stroke H, the sealing lip can work with a virtually uniform outer circumference in every position of the oscillating piston 3. This theoretical condition is satisfied.

The above geometrical considerations give approximate values.

According to the invention, it is possible in practice to adapt the diameter history D3α to the simple manufacturability of the pump cylinder 2.

In the plan view of FIG. 6, in order to clearly show the sealing area of the inclined piston, the sealing area seen in the perspective view is shown by a dashed line.

Another embodiment of the invention is shown in FIGS. 7 and 8. The swinging piston pump 101 shown in FIG. 7 is substantially similar to the swinging piston pump shown in FIG. However, in the embodiment shown in FIG. It extends to As can be seen from Fig. 7, the oscillating piston pump 3
is provided with a second sealing sleeve 110 near the first 7-lead sleeve 1o already described in FIG. 1, and this sealing sleeve 110 is
- by means of the knob region 112 the first sealing sleeve 1o;
In other words, it is running in the opposite direction, towards the crank chamber. During the suction stroke of the oscillating piston, the crank chamber 19 rubs against the Litz area 12 and no air actually flows into the pump chamber 4 . Unwanted peeling movements of the lip region 12 and the pump noises caused thereby are significantly reduced.

Practical evidence shows that the oscillating piston pump 101 configured in this way operates very quietly.

If both sealing sleeves 10, 110 are made of the same size, relatively simple manufacture and replacement is possible. The thickness a of the radial sleeve portion 11.111 corresponds to the lip area 1
It is also possible to use a sleeve 10, 114 with a thickness b of 2.1'12.

By using two sealing sleeves 10, 110, the radial support can be increased by 5K, as detailed in FIGS. 1-6. If necessary, the sealing sleeve with two lip regions 12° 112 can also be formed in one piece. Optionally, the second lip region could be designed as a short annular bulge in the form of a lip that protrudes into the crank chamber.

Such an annular ridge fits well into the cylinder wall 13. Optionally, a nearly closed annular cavity 20 can be formed between the two lip regions 12, 112 and the cylinder wall 13, as shown in FIG. In this way, a kind of labyrinth seal is formed during operation of the oscillating piston pump. For example, crank chamber 19
If some air passes along the lip area 112 facing , this air flow forms a small vortex 21 .

This situation is shown in an exaggerated manner in FIG. In this case, a certain degree of labyrinth seal is formed in the nearly closed annular chamber, as already mentioned.

A rocking piston pump with two lip regions 12, 112 makes it possible to obtain a relatively large degree of vacuum. In this type of single stage pump configuration, 100 Torr
The following pressures can be obtained.

Oscillating piston pump 101 shown in FIG. 7 or 8
A particularly advantageous use of this is that it is used as a vacuum pump.

FIG. 9 shows a one-piece sealing sleeve A1 which has been significantly reduced compared to FIG. The lip region 112a,'- pointing in the direction of the crank chamber 19 is designed in a shortened manner as a kind of annular bulge 22. At the transition from the annular ridge 22 to the radial sleeve part 111, a radially oriented groove 23 is provided, which serves to bring the annular ridge 22 into contact with the cylinder wall 23. It will be done.

The invention is not limited to the illustrated embodiment.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a rocking piston pump according to an embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional view of a seal sleeve of the rocking piston pump shown in FIG. Figure 4 is an explanatory diagram showing the three positions of the pump cylinder. Figure 4 is an explanatory diagram showing that the diameter of the center of the pump cylinder is slightly reduced. Figure 5 is a top view of Figure 4. Figure 6 is the geometry of the swinging piston. FIG. 7 is a reduced longitudinal sectional view of another embodiment of a longitudinal sectional view of a rocking piston pump according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Rocking piston part pump, 2... Pump cylinder, 3... Rocking piston, 4... Pump chamber, 5...
Bearing, 6... Eccentric bearing part, 7... Piston part, 8
...Bearing part, 9...-? Stone part, 10... Seal sleeve, 11... Sleeve part, 12... Lip range, 13... Cylinder wall, 14... Annular gap, 1... Groove, l6... Screw, 17...Central range, 18...Vertical axis line, 19...Crank chamber, 2o...-
Hollow chamber, 21... Vortex, 22... Annular protuberance, 23.
(No change in groove force) Procedural amendment (method) Date of July 9th, 1981, Mr. Commissioner of the Japan Patent Office 1.1. stomach! l: , 7) , +79 1982 Patent Application No. 166818 2, Title of Invention: Oscillating Piston Pump 3, Relation to the Amendment Case To the Patent Applicant: Name: Erich Benokur 4, Sub-Attorney: 6 , drawing 7 subject to amendment, attached sheet of amendment details, but engraving of the drawing (no change in content)

Claims (1)

Claims: 1. A piston pump having at least one sealing sleeve, the sealing sleeve comprising a sleeve part which extends in the radial direction and is at least partially held by the piston part, and a cylinder wall G. In those types with a close-fitting lip area, the wall thickness (a) of the radially extending sleeve part (11) is greater than the wall thickness (a) of the lip area (12) of the sealing sleeve (10). Thickness (b) &
A rocking piston pump is characterized by its large size. 2. Oscillating piston pump according to claim 1, wherein the maximum wall thickness (b) of the sealing sleeve (1o) in the groove area (12) is approximately 0.6 mm. 3. Claims 1 or 2, wherein the sealing sleeve (1o) is formed in an approximately cup-like shape with a thick-walled bottom portion and a horn region (12) that stands up on the side. Oscillating piston pump as described. 4. The oscillating piston pump according to claim 3, wherein the transition from the radially extending sleeve part (11) to the lip region (12) is designed to be slightly pivotable. 5. The rocking piston pump according to claim 4, wherein the seal sleeve (10) is replaceable from the pump chamber side. 6. A claim in which the swinging piston has a support portion below the sealing sleeve, and the diameter (D2) of this support portion is smaller than the diameter (DI) of the upper piston portion (9). The rocking piston pump according to item 5. 7. The inner diameter (D3) of the pump cylinder (2) is formed as a diameter (D3') that is slightly reduced compared to the maximum cylinder diameter (D3) in the central range (17) of the histone stroke. A rocking piston pump according to claim 6. At an oblique position of the swing piston (3) corresponding to the crank angle (α), the outer periphery of the ellipse corresponding to this oblique position is at the top dead center or the bottom dead center G. 8. The oscillating piston pump according to claim 7, wherein the inner diameter (D'3α) of the pump cylinder (2) changes over the piston stroke (H) so as to correspond approximately to the outer circumference of the +p cylinder. 9. The sealing sleeve is directed towards the pump chamber'v) f::
'J' 7 section and radial sleeve section (11
1) and a second lip region (112) extending substantially in the direction (X) toward the crank chamber.10. Claim 9, wherein the piston (3) is provided with a second sealless knob (110), the lip area (112) of this second sealing sleeve being directed into the crank chamber. 11 The thickness of both sealing sleeves (10, 110) in the radial sleeve part (11, 111) a) corresponds to the thickness of the lip area (12, 112) b') c. A rocking piston pump according to claim 10, which is formed by: 12. Oscillating piston pump according to claim 9, wherein the sealing sleeve with two lip areas (12, 112) is integrally molded. 13 Between the two lip areas (12, 112) and the cylinder wall (53) loaded by these lip areas, a hollow chamber (2o) in the form of a closed ring is provided. A rocking piston pump according to claim 9. (4) The rocking piston pump according to claim 9, wherein the rocking piston pump (110) is formed as a vacuum pump.