WO2009046558A1

WO2009046558A1 - Device for lubricating the bearing points of a connecting rod, operating method therefor and plunger pump comprising a device of this type

Info

Publication number: WO2009046558A1
Application number: PCT/CH2008/000420
Authority: WO
Inventors: Anton Steiger
Original assignee: Anton Steiger
Priority date: 2007-10-11
Filing date: 2008-10-08
Publication date: 2009-04-16

Abstract

The invention relates to a device for lubricating the bearing points of a connecting rod (106, 206) comprising a bearing (10, 110, 210, 121, 221) on each of the small ends of the connecting rod (106, 206) and a counter-bearing that co-operates with said bearing (20, 120, 220, 111, 211). The bearing (10, 110, 210, 121, 221) and the corresponding counter-bearing (20, 120, 220, 111, 211) can oscillate in relation to one another and are subjected to more intense and weaker stress during a motion cycle. A lubricating gap (30, 130, 131, 230, 231) of variable thickness (d), into which a lubricant supply line (32, 132, 133, 232, 233) opens, is formed between the bearing (10, 110, 210, 121, 221) and the corresponding counter-bearing (20, 120, 220, 111, 211). A non-return valve (40, 140, 141, 240, 241) is situated in the lubricant supply line (32, 132, 133, 232, 233). In addition, the lubricating gap (30, 130, 131, 230, 231) is provided with a lubricant trap (34, 134, 135, 234, 235). The invention permits the production of a predominantly motion-independent lubricant film in the lubricating gap and thus the reduction of the friction in oscillating moving bearing assemblies to a negligible value. One particularly advantageous application is for the bearing points of connecting rod-driven plunger pumps.

Description

Apparatus for lubricating the bearing points of a connecting rod, method of operation therefor and plunger pump with such a device

The invention relates to a device for lubricating the bearing points of a connecting rod with oscillating load and an operating method therefor according to claims 1 and 14. The invention further relates to a connecting rod pump with such a lubricating device according to claim 11 and a bearing assembly according to claim 19.

Dynamic plain bearings with two bearing elements which move continuously relative to one another and a lubricant which flows through a lubricating gap between the bearing elements and which builds up a lubricant film, in particular oil, are generally known. They are used in particular for non-reciprocating movements of the bearing elements, e.g. For lubricating bearings with rotating, approximately constantly loaded axles. The lubricant is supplied continuously and taken from the relative to each other in always the same direction moving bearing elements and distributed over the lubrication gap, which thereby has an approximately constant thickness. Only by the uniform rotational movement of the bearing elements succeed in these cases, the structure of a lubricant film.

In the case of bearings with oscillating or reciprocating movements, as occur, for example, at the bearing points of connecting rods, however, there is the problem that the relative speed between the two bearing elements fluctuates between zero and a maximum speed and the direction of the relative movement changes. At the reversal point of the movement there is a risk that the lubricant film breaks off. This problem is exacerbated when the bearing assembly is subjected to strongly varying forces within a cycle of motion, eg when translating a rotary motion into a reciprocating motion by means of a swash plate or eccentric roller assembly. This leads to heavy wear of the bearings and to undesirable stresses on plungers driven by the connecting rods, and should therefore be avoided.

Such an application is known from DE-A 37 10 071 and deals with the problem of lubrication for the bearings of the spherical conrod heads in the plungers and on the swash plate of a swash plate type compressor. It discloses a device according to the preamble of claim 1, in which a through the swash plate and through the connecting rod through hole is provided to improve the lubrication, is continuously passed through the oil to both bearings. However, there is the problem here that the oil from the lubrication gap, which is above the active, i. loaded, bearing surface has approximately the same thickness, is pressed back into the feed and does not flow through the lubricating gap, when the load of the bearing is greater than the force exerted by the supply pressure of the lubricant hydraulic force, and the oil film can thus break off. This leads to increased wear of the bearing and can lead to short-term seizing of the connecting rod in the bearing shell and resulting lateral forces on the connecting rod bearings and the coupled plungers.

Especially with such swash plate compressors or pumps and also other types of plunger pumps, the above-mentioned problem means that the load on the bearings of those elements which transmit force to the plugs must be kept low. This relates in particular to a power transmission with reciprocating moving, in particular pivoted about an axis connecting rods. At present, the pressures to be generated by such pumps for liquids are limited to a few hundred bars because of the load limits of the hitherto existing transmission elements between the drive and the plunger. GB 694,521 discloses a floating bearing for a substantially constant loaded rotating shaft in which continuously introduced lubricant from a plurality of circumferentially equidistant feeds in a lubrication gap between the cylindrical shaft and the hollow cylindrical bearing bush and over compared to the circumference relatively wide axially extending grooves drains off in the axial direction. In the feeders check valves are arranged in each case, which serve to prevent short-term disturbances, such as a deflection of the shaft in the radial direction, the lubricant drain and to avoid contact of the shaft with the bearing bush. This arrangement is not suitable for oscillating moving and loaded bearings, since here the lubricant film is built up in the circumferential direction only by the relative movement of shaft and bearing bush. At a standstill or with small reciprocating movements, therefore, the lubricant flows off in the axial direction, so that no coherent lubricant film is built up.

The invention is therefore an object of the invention to provide a device for lubricating the bearings of pendulum moving and oscillating stress exposed connecting rods, in which a secure lubrication is ensured even under high load. In addition, the transverse forces arising as a result of the connecting-rod deflection and acting on the plungers, consisting, on the one hand, of frictional forces, are largely eliminated due to a lack of lubricant film thickness and those due to the con-rod deflection should be kept as low as possible. Furthermore, an operating method for such a device is to be specified.

The object is achieved by a device having the features of claim 1 and a method having the features of claim 14. Particularly advantageous is a plunger pump with a lubricating device according to the invention according to claim 11. The advantages of the invention are generally in a rotary or ball joint-like Bearing arrangement realized with the features of claim 19. Further advantageous embodiments of the invention are in the dependent Claims and indicated in the description and the drawings.

In connection with the invention, plunger is used synonymously with piston or plunger and plunger pump synonymous with axial piston pump.

In contrast to purely hydrodynamic bearings, in which lubricant is entrained into the lubrication gap only by the relative movement of two bearing elements, the invention uses a different mechanism of action for the production of a lubricant film which does not tear off at the reversal points despite alternating load and regular stoppage of motion. By appropriate geometric design ensures that the lubricant can flow only through the lubrication gap. It is therefore forced out of the lubricant supply into the lubrication gap and flows off at the periphery of the bearing surface or the lubrication gap. The bearings and their abutment are therefore preferably designed so that the flow resistance for the lubricant from the mouth region of the lubricant supply from in all directions is substantially equal. Preferably, the mouth region is such that even under load a largely symmetrical force and thus gap thickness distribution is realized, ie on the axis of the connecting rod. The preferred spring-loaded check valve prevents the backflow of lubricant from the lubricant pocket into the lubricant supply when the pressure of the lubricant in the lubricant pocket exceeds the supply pressure of the lubricant, ie in the phases of heavier loading of a cycle of movement. In this way it can be prevented that the thickness of the lubricating gap decreases to zero and it is ensured that the lubricant flows only through the lubricating gap, but not through the supply. The lubricant pocket serves as a reservoir for the lubricant and facilitates the preferably very rapid refilling of the lubrication gap with decreasing load. At every point in the movement cycle, a lubricating film is thus present in the lubrication gap, lubrication is improved, thus increasing the service life of the bearing points and the load capacity. Undesirable lateral forces cause mechanical shear friction, due to temporarily missing lubricating film, are completely avoided.

The inventive lubricating device is designed in particular for the bearing points of a connecting rod, which is exposed during a movement cycle alternately stronger and weaker load on pressure or train, in particular in the direction of the connecting rod. At the same time, the relative movements between the bearings on the connecting rod are limited to small angles. However, the design of the bearings with a check valve in the lubricant supply and a lubricant bag with sharp-edged crossing to increase the Abströmwiderstands is basically suitable for all articulated arrangements of two with a limited angular range with one or two degrees of freedom against each other pivotable elements.

Particularly preferred is the application of the invention at the bearing points of a connecting rod and the associated bearing at the drive end of the plunger. The phase of heavier load is, for example, the phase in which the connecting rod pushes the plunger into its guide and thus the bearing is subjected to pressure. The phase of weaker loading is accordingly the phase in which the plunger is pulled out of the guide again.

Preferably, the geometric characteristics of the lubricating gap or the lubricant pocket influencing the flow properties, the elastic properties of the lubricant, such as its viscosity and compressibility, and the actual load on the bearing arrangement and their temporal distribution within a movement cycle, are matched to one another during the phase Load does not run through the narrowing lubrication gap all the lubricant present in the lubrication gap. Preferably, therefore, the thickness of the lubricating gap, despite the lubricant flowing through the lubricating gap, is greater than a predetermined minimum thickness at any point in time of the movement cycle. This is for example between 0.001 and 0.01 mm and is preferably 0.005 mm. The flow rate of the lubricant is determined, inter alia, by the shaping of the lubricating gap and the lubricant pocket influencing the flow characteristics. In order to increase the flow resistance, the lubricant pocket in the border region to the lubrication gap preferably has a clearly trained transition edge (in contrast to a smooth transition). In other words, the surface of the lubricating gap adjoining the lubricant pocket and a side wall of the lubricant pocket strike one another at a non-zero angle β, which is preferably approximately 80 to 90 °. In the application, the lubricant flows along said surface of the lubricating gap, so that a pronounced contraction effect arises with respect to the lubricant flowing into the lubricating gap. The bag or its side wall is located within the active bearing surface, ie that surface within the contact surface of the bearing and its counter bearing, which is exposed to the load.

In order to define an exact length of the lubrication gap in the flow direction, one of the bearing elements has a drain groove which surrounds the lubricant pocket in its circumferential direction and is spaced therefrom. The groove can be located in that bearing element in which the lubricant pocket is also formed, or in the other bearing element. The groove is located in particular transversely to the outflow direction of the lubricant.

The depth of the lubricant bag is preferably such that a clear transition edge can be formed. Preferably, however, the lubricant pocket is not so deep that its volume completely absorbs the pressurized lubricant during the period of heavier loading so that drainage through the lubrication gap would be suppressed.

Depending on the force exerted on the bearing elements, the pocket diameter largely determines the pressure prevailing in the pocket. In particular when used with plunger pumps, the ratio of plunger diameter to pocket diameter is one of the possible delivery pressure. size. The optimum ratio between delivery pressure and pocket pressure depends on various considerations, for example, a smaller pocket diameter leads to a larger bag pressure, but also reduces the cross section when flowing into the lubrication gap and thus increases its flow resistance. Other parameters include the compressibility of the lubricant.

In order to bring the bearings and counter bearing during the phase of weaker load back to their original, in particular maximally spaced position, and to increase the lubricating gap again, the supply pressure of the lubricant is preferably selected so that the lubricant during the phase weaker load within this Movement cycle acting on the bearing elements hydraulic force is greater than the sum of all other forces that press the bearings and counter-bearing during this phase against each other. Preferably, the feed amount of the lubricant is selected so that the thickness of the lubricating gap increases again during the phase of the weaker load up to a maximum thickness.

According to the invention, the bearings and abutments of the connecting rod lead relative to each other through a pendulum movement with a limited maximum deflection. This is many times smaller than the circumferential extent of the active bearing surface.

Thanks to the invention, a significant increase in the pressure on the plunger up to 1000 bar and more can be achieved in particular with plunger pumps with swash plate drive and a power transmission by means of connecting rods between swash plate and plungers. In such devices, the maximum deflection relative to the central axis of the connecting rod is preferably about +/- 2-5% of the stroke of the plunger. The basic structure of such a compressor with a drive of the plunger on a swash plate and connecting rod is known for example from DE-A 44 20 680; The production of high pressures was with such a device, however, because of the previously unsolved problem of oscillating burden- th bearing problematic. Another preferred application is an eccentric drive and power transmission by means of roller and lever assembly on the connecting rods. Both variants are described below with reference to the drawings.

The invention is characterized in that it ensures a lubricant layer with a certain minimum thickness analogous to the hydrostatic bearing concept. It can be worked with low lubricant pressure in the order of a few bar and can be dispensed with a high-pressure lubricant supply. Finally, no throttle modules are needed to stabilize the lubrication gap thickness.

A further advantage of connecting rod-driven plunger pumps with a lubricating device according to the invention is that the frictional forces transmitted by the connecting rod bearing to the plunger are negligibly small in contrast to conventional bearings, since these, as already described, are in each operating state ensure hydrodynamic lubrication and thus produce only a negligible friction torque due to the extremely low sliding speeds of the connecting rod bearings. In contrast, in the case of conventional connecting rod bearings, the completely different friction conditions prevent a purely axially symmetrical force distribution from being achieved on the plunger foot. If the hydraulic displacement forces between the plunger and its guide arising from the transverse pendulum movements are greater than the lateral forces acting on the plunger, contact between the plunger and the guide can be avoided. The parameters influencing this effect are frequency, delivery pressure range and viscosity of the pumped medium as well as the gap thickness.

By virtue of the invention, the swashplate type of drive known per se can also be used for high-pressure pumps. A preferred field of application is fuel injection pumps. A swash plate assembly eliminates the otherwise required drive systems with cranks and crossheads. Such an arrangement is space-saving and can be due to the cy- cylindrical shape are placed directly on the end flange of a stationary drive motor.

Warehousing is simplified, as per engine type a single pump unit is needed, which can be easily adjusted by changing the swash plate angle of attack to each cylinder number.

Examples of the invention are shown in the drawings. It shows purely schematically:

1 is a schematic diagram of an inventive bearing and thrust bearing in section,

Fig. 2 shows an example of a plunger pump with a swash plate and a connecting rod for power transmission in section, Fig. 3 is a detail view of a connecting rod with an inventive

Lubricating device for use in a plunger pump according to FIG. 2,

4 shows the dependence of the thickness of the lubricating gap on the angle of rotation of the swash plate in a device according to FIG. 2; FIG. 5 shows the dependence of the transverse stability of the plunger on the angle of rotation of the swash plate in a device according to FIG. 2 compared to conventional bearing arrangements;

6 shows an example of a plunger pump with plungers and eccentric drive constructed in a boxer arrangement, and FIGS. 7 and 8 show detailed views of a connecting rod with a plunger according to the invention

Lubricating device for use with a plunger pump according to FIG. 6. Fig. 1 shows an example of an inventive bearing assembly with a bearing 10 in the form of a ball with center M or spherical cap and an anvil 20 with complementary shape in section along a longitudinal axis A of the connecting rod. The bearing assembly is substantially rotationally symmetrical to the axis A, so that a relative movement with two degrees of freedom is possible. In this case, the bearing arrangement is designed around the point M in the manner of a ball joint with pivoting capability. If only one degree of freedom is sufficient, the representation can also be viewed as a section through cylindrical bearings or abutments, ie bearings and abutments can be arranged in the manner of a swivel joint with pivotability about an axis perpendicular to the plane through M (see Fig .. 7+ 8th). In a lubricating device according to the invention, both connecting rod heads and their abutments have the shape shown in FIG.

Bearings and thrust bearings 10, 20 can be inserted into each other substantially accurately, but with a certain play and can relative to each other perform a pendulum motion around the center M (one or two degrees of freedom). The maximum deflection of the axis of symmetry A of the bearing 10 from its rest position by an angle α of about ± 1 ° is shown in dashed lines and denoted by A '. The direction of the action of force on the bearing, for example given by the orientation of a plunger coupled to the connecting rod, is denoted by B and coincides in the rest position with the direction of the axis A. In order to reduce the friction between the two adjacent surfaces 12, 22, a lubricant is introduced into the lubrication gap 30 formed between them due to the play via a lubricant supply 32. To form a lubricating film, the lubricant is pressed during operation of the discharge point 32 'of the lubricant supply 32 into the lubrication gap 30 and flows out of this peripherally in the flow direction S again. The lubricating gap 30 has a variable thickness d due to the changing load. The Münungsstelle 32 'in the lubricant pocket 34 is located in the region of the axis of symmetry A. In order to prevent the flow of the lubricating film from stopping and breaking off in the direction of the axis A upon reversal of the movement or excessive load, corresponding to at least locally a thickness d = 0 of the lubricating gap, the area 32 'is located in the area of the outlet Lubricant supply 32, a check valve 40. This prevents drainage of the lubricant in the lubricant supply 32 in phases of heavier load. In the present case, the check valve 40 has a spherical valve body 42, which is biased by a second bearing element 20 anchored or supported spring 44 against a valve seat 46 acting as a conical region of the discharge point 32 '. The valve seat 46 is shaped so that the above-mentioned oscillating movement of the bearing elements 10, 20 is possible. But it is also possible that the check valve 40 is anchored completely in the first bearing element 20 (see Fig. 3, lower bearing assembly).

The flow resistance of the lubricating gap 30 must not be too low, so that the thickness of the lubricant film is not too small. In order to increase the flow resistance, a lubricant pocket 34 is formed in the bearing 10 by a recess in the region around the discharge point 32 ', which has a circumferential transition edge 36 at the transition to the actual lubrication gap 30. The angle β has a value of 80-90 °.

At an angle δ of about 45 ° from the axis A is in the surface 12 of the bearing 10, a circumferential groove 38. This defines the outer edge of the lubricating gap 30 and the active, i. the exposed bearing surface. The surfaces 12, 22 are not loaded beyond the groove or to a lesser extent. The lubricant can i.a. drain through the groove 38.

FIG. 2 shows a swash plate drive plunger pump 100, in particular for a fuel pump. The rotational movement of a shaft 114 is transmitted to the inclined disc 108 and thus sets the swash plate 109 in a corresponding up-and-down movement. The swash plate 109 in turn imparted via the connecting rod 106 to the plunger 102, in the cylindrical Guide sleeve 104 is stored, the lifting movements. The axis A of the connecting rod 106 is substantially coincident with the axis of the plunger 102 and thus the axis B of the force with the exception of small oscillating transverse movements of the connecting rod 106 to compensate for the different radial position in the upper and lower positions of the swash plate 109. Straight these oscillating movements with small amplitude and also the load fluctuating very strongly between train and pressure make special demands on the bearing points for the two connecting rod heads 110, 121 of the connecting rod 106, which have hitherto not allowed the generation of a high pressure by means of a swash plate drive. In the present case, a bearing arrangement according to FIG. 3 with a bearing (connecting rod head) and the corresponding abutment with lubricant feeders 132, 133 and check valves 140, 141 arranged therein is used for constructing a lubricating device according to the invention for both bearing locations. This is shown in Fig. 3 in more detail. This lubricating device will be described in more detail below. Thus, the pressure to be generated can be significantly increased.

Fig. 3 shows a connecting rod 106 with two Pleuelköpfen 110, 121 and associated plunger and drive side thrust bearings 120, 111, which are constructed to smaller details as shown in Fig. 2. Differences are that the lubricant pockets 134, 135 and the circumferential grooves 138, 139 are arranged in one case on the Pleuelköpfen 110, 121 and in the other case in the abutments 120, 111, since both variants represent equivalent solutions.

The plunger-side connecting rod 110 is mounted to form a spherical surface lubricating gap 130 in a connected to the plunger 102 thrust bearing 120 with an inverse spherical surface (center M). The basic structure corresponds to Fig. 1 with the difference that the lubricant bag 134 is not formed in the connecting rod 110, but in the counter-bearing 120 here. Their shape and function, however, is as described above with reference to FIG. The lubricant supply 133 extends inside the connecting rod 106 along its axis A. In the mouth region, a check valve 140 is arranged.

The drive-side lower connecting rod 121 is also mounted in an adapted to its shape abutment 111, wherein also a spherical surface-shaped lubricating gap 131 (center M ') is formed. In the lower counter bearing 111 is the main lubricant supply 132, which feeds through the lubricating gap 131 and extending through the connecting rod 106 lubricant supply 133. Return into the feed 132 is prevented by means of a further check valve 141.

During the more heavily loaded movement phase (pressure on the plunger or upward movement of the swash plate), therefore, a return of the lubricant from the lubricating gap 130, 131 into its associated supply 132, 133 is prevented by the valves 141, 140. Furthermore, too rapid outflow is prevented by the form of the lubricant pockets 134, 135 explained in more detail with reference to FIG. 1.

FIG. 4 shows, by way of example, the gap thickness d as a function of the angle of rotation of the swashplate or of the shaft driving it in a connecting-rod bearing arrangement according to FIG. 2 or 3, ie as a function of the load of these bearings for an oil viscosity of SEA20. Over an angular range of 0 to 180 ° - corresponding to the more heavily loaded movement phase of this bearing (lifting phase of the plunger) - the gap thickness d decreases from initially approximately 0.06 mm first very strongly, then more slowly sloping down to approximately 0.005 mm. When switching from stroke to pulling movement at an angle of 180 °, ie at the beginning of the suction stroke, the lubricating gap thickness changes only imperceptibly, since the decompression of the lubricant continues up to 225 °. Thereafter, the gap thickness d abruptly increases again to about 0.06 mm and remains at this level during the rest of the weaker loaded movement phase (225-360 °). The feed amount of the lubricant is preferably selected so that the distance between the surfaces The bearing elements also corresponds to the actual thickness of the lubricant film, ie that no foreign substances such as air are trapped.

5 shows the transverse stability of the plunger with a lubricating device according to the invention in comparison to a conventional bearing. The torque relative to the center of the plunger (bold curve), which is due to the practically missing frictional forces caused exclusively by the Pleuelauslenkung changes sinusoidally and completely symmetrically with respect to the central axis of the plunger over the entire stroke range with the rotation angle of the drive shaft. The plunger thus executes a gentle pendulum motion about its axis. This can therefore be stabilized by the pumping medium, which is present between the plunger and its guide, so that a metallic contact between the piston and guide surface is excluded.

In a conventional connecting rod there is boundary lubrication in its bearings, which leads to substantial frictional forces. As a result, as can be seen from FIG. 5, neither a sinusoidal nor a central axisymmetric moment characteristic can arise.

In a plunger pump according to Fig. 2, for example, with a pump suction pressure of 7 bar, a pressure of about 1000 bar are constructed. As a supply pressure of the lubricant, in particular oil, is sufficient for example 10 bar. A pump speed of 1500 rpm can be achieved, which should not be undercut, since otherwise the minimum required lubrication gap thickness would no longer be ensured.

The lateral relative movements of the centers of bearing and thrust bearing must be small; Preferably, the maximum displacement between the centers M, M 'of the Pleuelköpfe 110, 121 in the transverse direction only +/- 1, 5% to 2% of the stroke of the plunger. The lubricating gap 130, 131 has a function of the viscous It has a minimum thickness of eg 0.01 mm (for oil according to SAE50) or 0.005 mm (for oil according to SAE20).

6 shows a further plunger pump 200 in section, in which the lubricating device according to the invention leads to a significant improvement in operating safety. It is an eccentric-type plunger pump in which the axes A, B and C are chosen with respect to their relevant distances so as to increase the stroke of the connecting rods 206 to the desired value. The present concept is particularly suitable as a water pump. There are each two plungers 202 in a boxer arrangement opposite (angle 180 °). The rotation of a drive shaft 214 is converted by means of an eccentric 208 in a synchronous pivotal movement of two levers 216. These are arranged on different sides of the eccentric 208 and braced against each other with a spring 218. By means of a connecting rod 206, the levers 216 are respectively connected to the plungers 202, so that the pivoting movement of the levers 216 is converted into an axial movement of the plungers 202 in their cylindrical guides 204. The pivot point D of the lever 216 must be positioned so that it has reached half the arc height of its pivoting profile when reaching half the target value of the Plungerhubs. Because of the reciprocal movement, there are also special requirements for the conrod bearings, which have led to the fact that eccentric drives with reciprocating connecting rods have not yet been used with plunger pumps. By using the lubricating device according to the invention, however, it is possible to improve the lubrication to such an extent that this technique can also be used for high-performance pumps.

The shape of the connecting rod 206 and its bearing on the lever 216 and the plunger is shown in detail in Fig. 7 and 8 in two different sectional views. The connecting rod 206 has two cylindrical connecting rod ends 210, 221 with an annular base. These act as a respective bearing and are mounted on a pin-like cylindrical counter bearing 220, 211 with a circular base. These are firmly connected to the lever 216 and the plunger 202. It will therefore be one cylinder jacket-shaped lubricating gap 230, 231 formed. The Pleuelköpfe 210, 221 and their abutment 220, 211 are coupled in the manner of swivel joints.

Via the lever 216 and the counter-bearing 211 assigned to it, lubricant is supplied to the lubricating gap 230 via a lubricant supply 232. According to the invention, a check valve 240 is again arranged in the lubricant supply 232; Similarly, a lubricant bag 234 is present - here in the counter bearing 211, alternatively in the connecting rod 221. Construction and function correspond in principle Fig. 1.

Analogously to the example of FIG. 2, the lubricant is passed through a further supply 233 to the plunger-side lubrication gap 231. Again, a check valve 241 is disposed in front of the junction and a lubricant pocket 235 available.

As shown in FIG. 7, the outflow of the lubricant from the lubrication gaps 230, 231 takes place via the relief grooves 238, 239.

Basically, in both variants, the entire suction stroke, i. the schwä- rather loaded movement phase, available to fill the pressure side lubrication gap of the two connecting rod bearings. The lubricant pressure required for this purpose is at the relevant time, i. the end of the suction stroke, determined because then the sum of all the bearing elements loading forces assumes the highest value. The feed quantity of the lubricant is given by the gap losses occurring during this time as well as the gap filling volume.

Claims

1. A device for lubricating the bearing points of a connecting rod (106, 206) comprising a bearing (10, 110, 210, 121, 221) formed on a respective one of the connecting rod ends of the connecting rod (106, 206) and in each case a cooperating counter bearing (20, 120, 220, 111, 211)), wherein the bearing (10, 110, 210, 121, 221) and the corresponding abutment (20, 120, 220, 111, 211) are oscillatory relative to each other and during a movement cycle alternately stronger and weaker load are exposed and wherein between the bearing (10, 110, 210, 121, 221) and the corresponding abutment (20, 120, 220, 111, 211) each have a lubricating gap (30, 130, 131, 230, 231) of variable thickness (d) into which a lubricant supply (32, 132, 133, 232, 233) opens, characterized in that the lubricating gaps (30, 130, 131, 230, 231) in or opposite the coin Areas of lubricant supply (32, 132, 133, 232, 233) each have a lubricant bag (34, 134, 1 35, 234, 235) and in that a check valve (40, 140, 141, 240, 241) is arranged in each of the lubricant feeds (32, 132, 133, 232, 233) of each bearing point.

2. Device according to claim 1, characterized in that the volume and Ausströmungswiderstand the lubricant bag (34, 134, 135, 234, 235) are adapted to the load of the bearing points and the elastic properties of the lubricant, that the thickness (d) of the lubricating gap (30, 130, 131, 230, 231) despite being run through the lubricating gap (30, 130, 131, 230, 231) lubricant at any time of the movement cycle is greater than a predetermined minimum thickness.

3. A device according to claim 2, characterized in that the minimum thickness of the lubricating gap (30, 130, 131, 230, 231) is between 0.001 and 0.01 mm, preferably 0.005 mm.

4. Device according to one of the preceding claims, characterized in that the lubricant pocket (34, 134, 135, 234, 235) to form a circumferential transition edge (36) in the lubrication gap (30, 130, 131, 230, 231) passes.

5. Device according to one of the preceding claims, characterized in that the lubricant pocket (34, 134, 135, 234, 235) has a side wall (37) whose surface (F) at an angle of at least 80 °, preferably 90 °, to Flow direction (S) of the lubricant in the lubrication gap (30, 130, 131, 230, 231) has.

6. Device according to one of the preceding claims, characterized in that the bearing (10, 110, 210, 121, 221) and / or the corresponding abutment (20, 120, 220, 111, 211) has a groove (38, 138, 139, 238, 239), which surrounds the lubricant pocket (34, 134, 135, 234, 235) and is spaced therefrom and which serves for the unimpeded outflow of the lubricant from the lubrication gap (30, 130, 131, 230, 231) ,

7. Device according to one of the preceding claims, characterized in that the check valve (40, 140, 141, 240, 241) is spring-loaded.

8. Device according to one of the preceding claims, characterized in that the bearing (10, 110, 121) and the corresponding abutment (20, 120, 111) have spherical surface-shaped surfaces, between which the

Lubrication gap is formed.

9. Device according to one of claims 1-7, characterized in that the bearing (210, 221) and the corresponding abutment (220, 211) zylin- dermantelförmige surfaces have, between which the lubrication gap is formed.

10. The device according to claim 9, characterized in that the two connecting rod ends (210, 221) has a cylindrical recess, in each of which a counter bearing (220, 211) acting cylindrical pin is used.

11. Plunger pump with at least one within a guide cylinder

(104, 204) axially movable plunger (102, 202), a drive, a drive and plunger connecting connecting rod (106, 206) and a device for lubricating the bearings of the connecting rod heads (110, 121, 210, 221) according to one of the claims 1-10 is realized.

12. plunger pump according to claim 11, characterized in that the connecting rod (106) on the drive side with a swash plate (109) is operatively connected.

13. plunger pump according to claim 11, characterized in that the connecting rod (206) is operatively connected to the drive side with an eccentric drive.

14. A method of operating a device according to any one of claims 1-10 having the following features:

- oscillating movement of the bearing (10, 110, 210, 121, 221) relative to the corresponding abutment (20, 120, 220, 111, 211), wherein bearings (10,

110, 210, 121, 221) and abutments (20, 120, 220, 111, 211) is alternately exposed to stronger and weaker loads during a cycle of motion;

- forming a lubricating gap (30, 130, 131, 230, 231) of variable thickness (d) between the bearing (10, 110, 210, 121, 221) and the corresponding abutment (20, 120, 220, 111, 211);

Blocking of the lubricant return by the lubricant supply (32, 132, 133, 232, 233) during the phase of greater load within a cycle of movement through a non-return valve (40, 140, 141) arranged in the lubricant supply (32, 132, 133, 232, 233) .

240, 241).

15. The method according to claim 14, characterized in that the supply pressure of the lubricant is selected so that the lubricant during the phase weaker load within a movement cycle on the bearings (10, 110, 210, 121, 221) and abutment (20 , 120, 220, 111, 211) acting hydraulic force is greater than the sum of all other forces, the bearings (10, 110, 210, 121, 221) and abutment (20, 120, 220, 111, 211) during this phase press against each other.

16. The method according to claim 14 or 15, characterized in that the feed quantity of the lubricant is selected so that the thickness of the

Smearing gap increases during the weaker load within a movement cycle to a maximum thickness, preferably before the end of the suction stroke.

17. The method according to any one of claims 14-16, characterized in that the duration of the phase of heavier load is shorter than the time that would be required to the total in the phase weaker load in the lubrication gap accumulated amount of lubricant from the lubrication gap (30, 130 , 131, 230, 231).

18. The method according to any one of claims 14-17, characterized in that the maximum pendulum angle (α) of the connecting rod (106, 206) relative to the central axis of the plunger in both directions is substantially equal.

19. Bearing arrangement with a bearing (10, 110, 210, 121, 221) and a relative thereto arranged in the manner of a ball or rotary joint, with a limited radius oscillating and oscillating movable counter bearing (20, 120, 220, 111, 211), wherein between the bearing (10, 110, 210, 121, 221) and the anvil (20, 120, 220, 111, 211) is formed a lubricating gap (30, 130, 131, 230, 231) of variable thickness (d) and the bearing (10, 110,

210, 121, 221) and / or abutment (20, 120, 220, 111, 211) a lubricant bag (34, 134, 135, 234, 235) and an opening into this Lubricant supply (32, 132, 133, 232, 233), characterized by a in the lubricant supply (32, 132, 133, 232, 233) arranged check valve (40, 140, 141, 240, 241).