WO2002027143A1

WO2002027143A1 - Motion converter and method for lubricating its sliding surfaces

Info

Publication number: WO2002027143A1
Application number: PCT/DE2000/003325
Authority: WO
Inventors: Reinhold Ficht
Original assignee: Reinhold Ficht
Priority date: 1999-03-26
Filing date: 2000-09-25
Publication date: 2002-04-04
Also published as: DE19913889A1; DE10085207D2; DE19913889B4; EP1320660B1; DE10085207B4; DE50013136D1; EP1320660A1

Abstract

The invention relates to a motion converter for a reciprocating piston machine, comprising a loop-shaped frame (7) which is connected to piston rods (5, 6) of the reciprocating piston machine in order to perform linear alternating movements and which has two sliding bearing surfaces (112) inside the frame which lie opposite each other and which extend crosswise to the direction of the linear alternating movements. A slide block (8) is positioned between these two sliding bearing surfaces and is suitably guided for a sliding movement, the crank pin (9) of a rotationally mounted crankshaft (10) being mounted in said slide block. A predetermined play is provided and is measured in such a way that the slide block (8) can perform a pendulous-type relative movement in relation to the frame (7) in the direction of the linear alternating movements and in dependence on the changes in direction and load. The two sliding bearing surfaces (82, 83) of the slide block (8) are interconnected by a bore system (97, 98) in the slide block (8) in such a way that a lubricant can be forcibly transferred from the gap with the greater load into the gap with the lesser load, in dependence on the changes in load of the two sliding bearing gaps.

Description

Movement converter and method for lubricating its sliding surfaces

The invention relates to a method for lubricating the sliding surfaces of a device for converting rectilinear alternating movements into a rotational movement and vice versa, in particular for reciprocating piston machines, and a movement transducer for carrying out the method.

The reciprocating piston machines mentioned have at least two axially identical, oppositely arranged working cylinders and a converter which is arranged in a crankcase. The converter converts the translational movements of the working pistons sliding in the working cylinders into a rotating movement of a crankshaft or vice versa. The crankshaft has a crank pin which is mounted in a sliding block (sliding piece). This performs rectilinear alternating movements between inner slideways of a frame-shaped loop, which in turn is firmly connected to the piston rods and is moved linearly within the crankcase by the crank rods. Such reciprocating piston engines can be used as a two-stroke internal combustion engine, as a four-stroke engine, as a reciprocating piston compressor or the like.

DE-A 3433 510 or EP-B 429 918 show such transducers consisting of sliding block and loop frame for such reciprocating piston machines.

A problem with such transducers is the reliable lubrication in the area between the inner surfaces of the loop frame, which are designed as slideways, and the sliding surfaces of the sliding block that interact with them. From US-A 4,794,887 it is known to use ball bearings or roller bearings for such a bearing. It is also known to convey lubricating oil from an oil pump assigned to the reciprocating piston engine through bores in existing gaps between the slideways or sliding surfaces. For this purpose, holes extend from the crank pin bearing to the sliding surfaces, which holes open into grooves or other recesses in the sliding surfaces of the sliding block. The grooves are arranged in a herringbone pattern on the sliding surface of the sliding block. The grooves start from a central groove that extends in the sliding direction. All grooves open in the area of the outer edges of the sliding surfaces. The sliding gaps are therefore constantly flowed through by the lubricating oil, the oil emerging from the gaps predominantly from the grooves open at the edges. A similar lubrication system is known from US-A 4,598,672. In addition, the sliding block in this known embodiment is on lateral guide surfaces of the sliding block and corresponding guide surfaces Guided cheeks of the loop frame. Groove-shaped recesses are made in the end regions of the guide cheeks, which correspond at one end to the transverse grooves of the sliding surface, so that oil gets into the recesses. At the other end, these recesses are open. Here, too, the oil supplied by the pump flows largely through the bearing system. Such an open pressure oil circuit has high leakage oil quantities. In order to keep these leakage oil quantities low, the sliding block is fitted to the guide surface of the crank loop frame with very little play. However, this has the consequence that caused in particular by high pressures between the sliding block and loop frame or when the sliding block is tilted in the frame

Frictional moment between the sliding block and the crank pin in it is not always guaranteed that there is an oil film of sufficient thickness between the sliding surfaces for a pure fluid friction. In these known systems, considerable wear and tear on the bearing surfaces and guide surfaces are accepted.

It is the object of the invention to propose a method in which the maintenance of a pure fluid friction is ensured even under difficult conditions, a converter designed in a corresponding manner being used to carry out the method.

The object of the invention is achieved once by a method according to claims 1 or 2. A converter according to claims 6 or 7 is used to implement the device.

The invention is based on the fact that the opposite sliding surfaces of the sliding block and the sliding surfaces of the frame are alternately loaded or relieved several times during one working cycle of the two piston-cylinder units. These load changes are used to maintain a reliable lubrication of the sliding surfaces mentioned. This is done in that, depending on the linear changes in movement and the associated changes in load of the layers that make it possible to slide in the two bearing gaps, the sliding block can execute corresponding pendulum movements of limited extent relative to the frame in the direction of the linear alternating movements, which are essentially perpendicular to the sliding surface run. With the help of these pendulum movements, lubricant is conducted from the higher-loaded layer into the lower-loaded layer. An inner system or one is thus obtained, possibly in addition to the outer lubricant system closed circuit between the two gaps to be lubricated. It has been shown that between the sliding surfaces of the sliding block and the crank loop there is always a liquid lubricant layer that is sufficient to optimize the sliding properties or sliding conditions, so that a defined hydroplaning is present over the entire sliding distance of the sliding surfaces in the working gap, even if the high pressure from a load or movement change occurs.

When one piston carries out a work cycle, a load is exerted on the frame of the crank loop via the piston rod, which is transferred to the sliding block. The sliding surfaces on both sides are pressed together. In the same way, the other piston-cylinder unit acts from the opposite side, at different times, so that there are increased pressures between the sliding surfaces during a back and forth movement of the sliding block, which shift or oscillate from one side to the other side of the frame. In addition, there are speed-dependent pressures, which result from the compression work of the pistons in the working area and in the piston underneath, e.g. B. result from the partition wall gas exchange room result.

In the context of the invention, it was consequently recognized that care must be taken to ensure that, at the point in time at which the pressings are imminent, sufficient cushion is built up in these load areas that is able to buffer the alternating pressure.

In contrast to the prior art, where there is as little play as possible between

Sliding block and associated frame is provided, the invention relies on that a game of predetermined minimum size is provided between the closely adjacent surfaces, so that the sliding block depending on the changes in movement relative to the frame a limited movement along the axis - that in the direction of movement the piston rod runs - can execute. This leads to a kind of breathing movement in the area of each gap, whereby this breathing rhythm is out of phase on both sides of the sliding block.

The bore system in the sliding block is adapted accordingly, so that an internal exchange system for the lubricant is created between the two gaps. The bore system must be designed so that the oil can pass from one lubrication gap into the other lubrication gap in very short periods of time without having to leave the lubricated gap too much oil flows out in this short time, so as not to endanger the lubrication in the sense of fluid friction.

Despite the sufficient play for the pendulum movements between the sliding block and the frame, the leakage oil losses can be kept as small as possible. The measures according to claims 8 to 18 take these demands into account.

It is particularly advantageous if the interacting sliding and guiding surfaces are smooth, that is to say have no grooves and depressions, except for the openings in the bores of the inner lubricant exchange system in the sliding block. The mouths of these bores lie directly in the sliding surfaces, specifically in predetermined areas of these sliding surfaces.

The game between the side flanks (guide surfaces) is significantly smaller than the game designed between the sliding surfaces, which the

Alternating movements or pendulum movements between sliding block and frame allows. The play with which the sliding block sits in the crank loop frame, together with the resulting pendulum movement of the sliding block in the frame, creates a pumping and guiding effect for the lubricating oil. On the one hand, this means that lubricant from the loaded liquid film can be partially pushed back into the holes in the sliding block that open on the surface. This creates a barrier pressure in these bores, which prevents the lubricant from entering the pressure pump into the loaded gap. For this purpose, the pressure of the lubricant coming from the pressure source will be lower than the pressure in the respectively more highly stressed gap.

On the other hand, there is an additional play in the gap that has just been relieved and thus a negative pressure. Both effects, individually or together, ensure that oil is conducted from the more heavily loaded gap into the unloaded gap, while at the same time the lubricant coming from the pump is deflected essentially exclusively into the unloaded gap. A film of sufficient thickness is thus built up in the relieved gap before the point at which this gap will be loaded, which ensures reliable fluid friction and buffering for the subsequent (striking) loading process of this gap.

The direct openings of the bores in the sliding surfaces of the sliding block ensure that all of the lubricant escaping into the lubricating gap between the sliding surfaces and inevitably contributes to the lubrication of these surfaces. Such a "closed" internal oil circuit has only minimal leakage oil losses in the lubrication gaps and, in conjunction with the pumping or guiding effect, ensures a safe interception of striking load changes (change of the loaded gap) due to the slag play for the pendulum movement of the sliding block.

Another advantage is that the pump only needs to be designed so that the lubricating oil it supplies is just sufficient to replace the low losses in the internal lubrication system.

In this context, it is expedient to use a crank loop frame which is open at the sides and at the ends, so that air and leakage oil displaced by the sliding block can be conveyed out of the interior of the loop frame.

The bearing surfaces of the sliding block do not have any internal grooves for guiding the lubricant. Likewise, the opposite slideway in the frame is not grooved, without oil flow-conducting inner grooves or tracks. However, this flat design does not mean that the sliding surface of the sliding block (also referred to as a sliding piece) has to be completely flat, rather it can also be designed slightly spherically so that it forms a slightly larger gap towards the end faces than in the middle, with respect to the slide of the frame. It is avoided that the sliding block, which is slightly tilted during the alternating movements at the reversal points, causes an increased pumping action by forming bow waves of lubricant, which would result in an increase in leakage losses. In addition, the slightly elastic, resilient design of the front ends of the slider contributes to reducing this effect, which give way to the reversal points causing tilting of the movement under greatly increased pressure, to avoid excessive gap reduction, which leads to the increased bow wave and the conveyance of lubricant which would lead to the pressure-bearing gap. The invention is explained in more detail below using schematic drawings using an example. Show it:

Figure 1 in a sectional view perpendicular to the crankshaft a four-cylinder two-stroke internal combustion engine;

Figure 2 in an exploded view essential parts of a transducer;

Figure 3a is a diagram showing load changes during one revolution; Figure 3b is a diagram showing the positions of the shaft to Figure 3a;

Figure 4,

Figure 5 in the same sectional view through the crank pin of the converter of

Figure 2 with different loading conditions of the bearing gaps S _a , S _b ;

Figure 6, Figure 7, Figure 8, Figure 9 shows a detail in different versions; and

Figure 10,

Figure 11 further examples of the execution of the inner or closed lubrication system.

Figure 1 shows the structure z. B. a four-cylinder two-stroke internal combustion engine with a section through the plane of a pair of cylinders 1, 2nd The second, identically constructed pair of working cylinders 11, 12 lies behind the first pair of cylinders in the illustration and is not covered by the section.

The two working cylinders 1, 2 are axially aligned and opposite one another, with a central axis 18a, which is designated by x. The working pistons 3, 4 are rigidly attached to piston rods 5, 6. At the other end, the piston rods 5, 6 are connected to a movement transducer device. For this purpose, the piston rods are fixedly arranged on a crank loop frame 7, in which a sliding block 8 is received. A crank pin 9 of a crankshaft sits centrally in the sliding block 8 as a polygonal piece. The converter is arranged in a crankcase 13, the interior of each of which is provided by a gas exchange chamber 14 of the respective cylinder 1 or 2 provided below the piston 3, 4 through a partition wall bearing 15 is sealed liquid and gas tight. A combustion chamber 17 is provided above the piston.

The operation of this piston-cylinder unit operated by ignition of an ignition device 16 is known. It therefore need not be described in more detail. It is only noted that gas pressure and mass forces overlap as a function of the pressure build-up in the respective gas exchange chamber 14 and combustion chamber 17 during operation, which leads to alternating pressures F _G = f _G (ω) in the region of a slideway 18, 19 between sliding block 8 and frame 7 comes during the rotational movement ω.

The converter is shown in FIG. The converter consists of the crankshaft 10 with at least one crank pin 9, which is rotatably supported in the sliding block 8 by means of slide bearing shells 43a, 43b, and the frame 7, consisting of the frame halves 7a, 7b, in which the sliding block 8 can slide in a straight line is.

For example, the crankshaft 10 is constructed in one piece as a single crank crankshaft. Depending on the type and / or size of the machine, it can also be constructed in several parts as a so-called built crankshaft. It has disc-shaped cheeks 22 as a means of swing or compensation, which are arranged on both sides of the crank pin 9.

Leading obliquely away from the circumferential surface of a bearing pin, penetrating the bearing pin 9 and the cheek 22, a bore 45 to the center of the crank pin 9 opens there into a transverse bore 46 penetrating the crank pin 9. The outer end of the bore is connected to a lubricating oil pressure source of the machine via a suitable system.

The sliding block 8 has a bearing bore 93 for receiving the crank pin 9. Two plain bearing shell halves 43a, 43b are provided for storage. The slide bearing shells 43a, 43b are thin-walled half-cylinder shells. The diameter of the inner surface of the slide bearing shell is such that it surrounds the peripheral surface of the crank pin 9 with little play in the assembled state. A circumferential groove 71 is provided in the center of its inner surface, in which passage bores 73 are made, distributed over the circumference. The position of the groove 71 is selected so that the transverse bore 46 of the crank pin 9 ends in the groove 71 at the end. In the case of small engines in particular, the sliding block 8 can be made from a sliding bearing material, so that the sliding bearing shells 43a, 43b could be dispensed with.

The sliding block 8, consisting of two halves 8a, 8b, clamps the bearing shells. It has a first sliding surface 82 and a second sliding surface 83 on opposite outer sides. These are flat, if necessary slightly spherical in the middle.

The areas adjacent to the sliding surfaces 82, 83 of the sliding block each form guide sliding surfaces (cheeks) 80, 81 (later 84a, 85a) and have a smooth surface. The sliding surfaces 82, 83 and / or the guide surfaces can, for example, be hardened and ground or have a coating made of sliding bearing material or can be covered with a sliding bearing plate. They preferably have no depressions, pockets or grooves. The sliding surfaces 82, 83 of the sliding block each form boundary edges 90 and 91 with the guide surfaces, which are preferably burr-free and sharp-edged or have a transition radius or a corresponding chamfer, which is explained in more detail below, cf. Figures 6 ff.

In the center of the sliding block 8, a crank pin bore 93 is provided with an inner surface 94, the inside diameter of which is slightly smaller than the outside diameter of the sliding shells 43a, 43b. As a result, the sliding shells 43 are gripped by the sliding block 8 in a clamping and non-rotating manner. The anti-rotation device can also be positively locked. In the center of the bore 93, corresponding to the bores 73 of the slide bearing shells 43a, 43b, there is a radially circumferential groove 95 which is approximately rectangular in cross section. Starting from this groove 95, the sliding block 8 has at least two, preferably four bores 97 distributed over the circumference, which run radially to the bore and at the other end approximately in the middle of the third of the sliding surfaces 82, 83 of the sliding block, which are outer with respect to the sliding direction, and open directly into these sliding surfaces 82.83. From the bores 97, bores 98 branch off approximately at right angles, which open directly into these near the outer ends of the middle third of the sliding surfaces 82 and 83, cf. Figure 4.5.

The sliding block is recessed on the end faces and forms tongues 88, 89 tapering towards the shaft 10 at the ends of the sliding surfaces. These are designed and dimensioned so that they can yield slightly elastically when a predetermined loading pressure is exceeded. This is in the situations in which due to a predetermined game the sliding block in Sliding gap in a tilting position inclined in the sliding direction, achieved that the resulting wedge shape of the gap in the sliding direction does not exceed a predetermined wedge angle. In this way, the possible leakage losses of the lubricant can be kept within narrow limits and direct contact of the sliding surfaces with one another can be avoided.

As FIG. 10 shows, the bore 97 can also be designed as a blind bore into which the branch bore 98 opens in such a way that an angled supply channel is formed. However, it is also possible to provide only the bores 97, which extend in a straight line (FIG. 11).

The sliding block 8 is preferably formed in two parts. If a built crankshaft is used, the sliding block 8 can also be in one piece. Connection means are provided for connecting the sliding block halves 8a, 8b. The fasteners are not shown for reasons of clarity, they are also e.g. known from DE-A 3435 501.

The lubricating oil (as an example of lubricant), which is supplied by an external pressure source of the machine, is in the inner groove 71 of the bearing shells 43. The lubricating oil supplied by this pump is adjusted in terms of pressure and quantity in such a way that essentially only unavoidable, but low losses are replaced due to the design of the converter, and the pressure is sufficient to allow the externally supplied lubricating oil to flow into the less loaded bearing gap.

The sliding block 8 is essentially form-fitting in the frame 7 in the axial direction y and in the sliding direction z, which is perpendicular to the axial direction and perpendicular to

Cylinder axis x of the working cylinder 1, 2 is straight, slidably guided. The crank loop frame 7 is preferably made in two parts, 7a, 7b. In the case of an engine with a built-in crankshaft, the frame 7 can optionally also be made in one piece. The frame halves 7a, 7b are formed symmetrically in the same way. They each have a web 110, the inside of which forms a sliding surface 112. The sliding surface or slideway 112 can be hardened and ground, have a coating of plain bearing material or be coated with a plain bearing plate, it should be noted that a surface-hard sliding surface interacts with a surface-soft slideway.

The longitudinal extent of the bearing surface 112 is selected such that the sliding surfaces 82, 83 are completely covered by the bearing surfaces 112 in the extreme position of the sliding block 8 in the sliding direction. Laterally in the frame are perpendicular to Slideway 112 leg webs 115, 116 formed in one piece in such a way that the frame halves 7a, 7b have an H-shaped cross section. At the ends pointing in the sliding direction, the frame halves 7a, 7b are each designed to be open in accordance with EP-A 429 918.

The piston rods 5 and 6 are attached, preferably in one piece, between the leg webs 115, 116. Bushes 121 are formed on the leg webs 115, 116 and are used to accommodate e.g. Expansion screws are used, with which the frame halves 7a, 7b can be firmly connected.

The leg webs 115, 116 have guide surfaces 127, 128 on the inside. These guide surfaces directly adjoin the sliding surfaces 112. The guide surfaces run parallel to one another and perpendicular to the slideway 112 and they collide with the slideway along a boundary edge 131. These areas, where guide surfaces and sliding surfaces meet, are preferably free of cuts or provided with a small transition radius or a small transition phase, as will be explained in more detail below. For the design of these transition or corner areas 131 or 132 it is provided that they are made as small as possible in cross-section in order to keep the amounts of lubricating oil (leaks) which inevitably escape at the open ends as small as possible.

FIGS. 6, 7, 8 and 9 each show the sliding block 8 in a starting position with a distance S1 from the sliding surfaces 112 and a distance S2 from the guide surfaces 127, 128. The gap thus formed is filled with lubricating oil. An extremely deflected position of the sliding block 8 is shown in dashed lines. In this position, the boundary edges 90, 91 have the reference symbols 90 ', 91'. FIGS. 6 to 9 are not to scale, but only illustrate fundamentally different configurations of the corner regions 132 between sliding surfaces and guide surfaces of sliding block 8 and frame 7. If the sliding block 8 is in its theoretical extreme position, in all embodiments according to FIGS 9, a residual corner channel 132 'is present. The cross-sectional area of this residual corner duct must be minimized.

According to FIG. 6, the sliding block 8 is sharp-edged on its boundary edge 90, 91 or has only a broken edge. The boundary edge 131 of the frame 7 is a free cut, but its dimensions are as small as possible. This version is particularly expedient if the guide surfaces 127, 128 and the sliding surface 112 have a ground surface is provided. According to FIG. 7, the boundary edges 90, 91 of the sliding block 8 and the limiting edges 131 of the frame 7 are designed as outer or inner phases and are adapted in such a way that a residual plug channel 132 'remains when the sliding block 8 comes to rest in its theoretical extreme position. The residual corner channel is trapezoidal in cross section. According to FIG. 8, the sliding block 8 and the frame 7 are each chamfered in the area of their boundary edges 90, 91 and 131, the planes of extension of the phase surfaces enclosing an angle to one another, so that the channel 132 'converges in cross section towards the guide surfaces 127, 128 and is thus wedge-shaped. According to FIG. 9, the boundary edges 90, 91 and the edge 131 of the sliding block 8 and the frame 7 are each provided with a radius, the radii being coordinated such that a sickle-gap-shaped channel 132 'remains.

The choice of the design of the corner channel 132 essentially depends on the size and type of the piston machine, the materials used for the individual parts and the manufacturing process. The embodiments according to FIGS. 7, 8 and 9 of the frame 7 are particularly suitable for machining the frame 7. The guide surfaces 127, 128 and the sliding surface 112 can be provided with surface coatings or treatments analogous to the sliding block 8 in order to further improve the sliding properties his.

The guide surfaces 127, 128 are at a distance from one another in the axial direction which is greater than the distance between the guide sliding surfaces 84a, 85a of the sliding block 8, so that the sliding block 8 is guided in the axial direction with a predetermined play S2. The game S2 is selected to be significantly smaller than the game S1 in the area of the sliding surfaces 112.

The oil that emerges from the openings 97, 98 and passes from the sliding surfaces 82, 83 via the boundary edge 90, 91 into this gap serves to lubricate the gaps formed between the guide surfaces 127, 128.

The leg webs 115, 116 are cut out in a U-shape, see 130. The cutouts extend into the vicinity of the sliding surfaces 127, 128.

The load on the sliding surfaces and layers of lubricating oil between them can vary during operation of a converter depending on the change of direction of the frame 7. The load essentially results from a superimposition of the gas pressure forces arising on the working pistons 2, 3 and the direction of their action opposite mass forces of the moving parts of the transducer. It can be seen from the diagram in FIG. 3a that the resulting sliding block forces F _{G are} plotted on the ordinate and the crank angle 0 <φ 180 180 ° is plotted on the abscissa. The curve shown represents, for example, the resulting sliding block forces, as they occur in an internal combustion engine for the specific speed of, for example, n = 4000 rpm. It can be seen that the load changes at φ ₁ = 4 ° for the first time, at φ ₂ = 41 ° for the second time and at φ ₃ = 79 ° for the third time, because the load curve intersects the no-load line there ,

In this case this means that during a rotation of 360 ° six

Load changes take place between the sliding block and the frame 7. For the positions Φι. φ ₂ > Φs ^s ' ^π d ^{un1: Diagrammr} the diagram shows schematically the pressure ^states that are present after passing through the points cp. ,, φ ₂ , φ ₃ . For example, in the area φ., <Φ <φ ₂ and the area φ> φ _3, the sliding surface 83 of the sliding block 8 loads the sliding surface 112 of the frame half 7a, while in the area <p ₂ <φ <φ ₃ the sliding track 82 loads the sliding track 112 the frame half 7b loaded. There is a clearance S between the relieved sliding block surface and the associated slideway of one frame half, as shown in FIG. 3b. The size of the play gap S results from the difference between the installation play S1 of the sliding block 8 and the thickness of the film on the loaded side of the sliding block 8.

Due to the forces F _G acting on it, the sliding block 8 performs a pendulum movement between the slideways 112 of the frame 7, which takes place at least once per revolution, depending on the speed and operating mode of the machine, as an internal combustion engine or as a reciprocating piston compressor. At certain speeds at which the gas and mass forces overlap so that the resulting load on the sliding block intersects the zero load line several times, this pendulum movement can also take place more than once per crankshaft revolution.

Such a pendulum motion is explained in more detail below with reference to FIGS. 4 and 5. In FIG. 4, the force F _G acts on the sliding surface 82 via the frame half 7b and loads an oil film 140 between the surfaces 82 and 112. This reduces the distance between the sliding surface 82 and the slideway 112, with the result that oil is displaced the gap S _b takes place between these surfaces. A part of the displaced oil is pressed around the boundary edge 90, 91 of the sliding block 8 between the lateral guide gaps and is used there for lubrication. Due to the relatively small axial clearance S2 of the sliding block 8 in the frame 7 only a small amount of leakage oil leaves the guide gap. A considerable part of the displaced oil penetrates into the bores 97, 98 and builds up a barrier pressure for the oil conveyed by the pump on the side of the loaded sliding block half. At the same time, due to the increase in the distance between the still relieved (not yet loaded) sliding surface 83 of the sliding block and the slideway 112 of the frame half 7a, a negative pressure is created in the gap S _{a there} with an oil film 141, which prevents the oil from flowing out on the relieved side of the sliding block 8 supported. The invention thus uses the pendulum movement of the sliding block in the frame to form a guiding and pumping effect that significantly supports the build-up of a sufficient lubricating oil layer. A sufficiently thick layer 141 is thus built up on the respective relieved side of the sliding block 8 before the loading, which ensures defined hydroplaning between the sliding loaded surfaces during the entire subsequent loading phase, in particular for the striking start of the loading. The pump effect produced by the pendulum movement interacts with the lubricating oil supplied by the mother oil pump, which is fed into the annular groove 71 through the bore 45, 46. The pumping action is made up of the displacement pressure in the bearing gap that is subject to higher loads and the negative pressure in the bearing gap that is subject to even less stress.

In order to prevent an unintentionally strong degradation of the loaded oil film 140, the bores 97, 98 are dimensioned in such a way that a sufficient amount of oil from the loaded lubricating film can get into the bore 97, 98 from the loaded lubricating film to achieve the pumping effect and to build up the barrier pressure. however, it is ensured that the loaded oil film 140 always has a minimum dimension required to maintain a sufficiently thick oil film during the entire loading phase. This can be achieved in that the oil feed bores opening into the sliding block surfaces, e.g. the bores 97 in the mouth area have a smaller diameter than the bores 98 further away from the edge, since the leakage oil losses which, although reduced according to the invention but not completely preventable, can make it necessary to reduce the partial quantity flowing back. This can be reliably counteracted by narrowing the holes near the edge in the mouth area.

If, for example at φ ₂ = 41 °, the direction of the resulting force F _G on the sliding block 8 reverses, as shown in FIG. 5, the oil film 141 becomes the loaded one and the oil film 140 the relieved one. Analogously to the situation in FIG. 4, the oil is now displaced from the gap S _b with the lubricant layer 141 and at least partially reaches the bores 97, 98, which open into and cause the now loaded sliding stone sliding surface 83 now pump back there and a barrier pressure. Here, too, the oil pumped by the oil pump for building up the oil film 140 flows from the bores 45 and 46 via the grooves 71 and 95, in the direction of the sliding surface 82 of the sliding block to the gap S _a . This changes when the load direction changes due to the resulting pressure conditions in the

Damping layers 141, 140 change the direction of flow of the oil in the bores 97, 98 of the two sliding block halves 8a, 8b.

The pumping effect is noticeably dependent on the size of the play gap S between the sliding block 8 and the frame 7, since, for example, play gaps which are too large can adversely affect the leaks emerging at the edge and thus the thickness and the pressure conditions in the sliding film. This is to be avoided especially at the reversal point of the sliding block, in that the sliding speed briefly assumes the value "zero" and the hydrodynamic load-bearing effect of the oil film is briefly absent. In this operating state, it must therefore be ensured that the loaded film between the sliding block 8 and the frame 7 is not weakened too much by edge leakage losses.

In the described configuration of the converter, utilizing the pump effect and / or the guiding effect between the loaded and unloaded sides of the sliding block (the opposite columns S _a , S _b ) in conjunction with minimizing the leakage oil losses in the pressure oil circuit, the converter is reliably achieved in critical operating conditions are reliably and permanently supplied with sufficient lubricating oil and a defined hydroplaning is ensured during operation. This means that there are always optimal sliding conditions between the sliding block and crank loop frame in any operating situation, and striking load changes cannot penetrate the increased buffer layer.

FIGS. 4 and 5 each show a “bow wave” 140a, 141a at the gap S _b , which is currently taking over the load, by a striking alternating movement of the sliding block from the previously loaded opposite bearing gap to the bearing gap now to be loaded. This indicated increased flow rate of a lubricant should be avoided as much as possible in order to assign the smallest possible leakages to the gap. A slight elastic compliance of the tongue 89, 88 is advantageous for this, which is achieved by the recesses 81 according to FIG. 2, which become clearer in the cross section of FIGS. A special form of the bearing surface 82, 83, which leads to a slightly increased edge area of the gap, is also advantageous for this purpose, in order to reduce the leakage losses.

Claims

Expectations:

1.Method for lubricating the bearing surfaces of a device for converting linear alternating movements into a rotary movement or vice versa, in particular for reciprocating piston machines, which movement transducer has a loop-shaped frame (7) which forcibly executes the linear alternating movements and has inner bearing surfaces (112) which run transversely to the alternating movements ) and has a sliding piece (8) which is slidable back and forth between them and a crankshaft which carries out the rotational movement, the crank pin (9) of which is rotatably mounted in the sliding piece, (i) the sliding block with the sliding bearing surfaces of the frame forming sliding gaps having; (ii) the two bearing gaps are held in connection with a source of lubricant to form sliding layers via the pivot bearing of the crank pin and an internal channel system in the sliding block; (iii) depending on the linear movement changes and the associated load change of the sliding layers in the two columns of the sliding block relative to the frame in the direction of the linear alternating movements corresponding pendulum movements of limited

Executes the extent and with the help of these pendulum movements each lubricant is guided in a controlled manner into the less stressed gap or is conveyed there from the more stressed gap; lubricant from the lubricant source being supplied to the bearing columns essentially only to the extent of leakage quantities emerging from the two columns.

2. Method for lubricating slide bearing surfaces of a device for

Converting rectilinear alternating movements into a rotational movement or vice versa, in particular for reciprocating piston machines, wherein

(a) a loop-shaped frame (7) forcibly carries out linear alternating movements and has opposite inner bearing surfaces (112) running transversely to these alternating movements for a sliding block (8) displaced to and fro between these or along these surfaces;

(b) a crank pin (9) rotates in the sliding block during its displacement movement, the sliding block with the bearing surfaces of the frame (7)

Has sliding surfaces (82, 83) forming bearing gaps;

(c) liquid layers (140, 141) are formed in the two bearing columns with an effect which favors the sliding action and are maintained in a thickness sufficient for sliding friction in the bearing columns, by - depending on changes in loading of the liquid ones

Layers (140, 141) in the two bearing columns - the sliding block performs pendulum movements of limited extent relative to the frame in the direction of the linear alternating movements, in order to promote liquid from the higher-loaded bearing gap into the less-loaded bearing gap or to promote its flow from one source into the lower one loaded

To favor the bearing gap, to build up a buffering liquid layer (141) in each case in the bearing gap which is less loaded before a load change.

3. The method according to claim 1 or 2, characterized in that the one of the gap in the other gap (S _b , S _a ) pumped or directed there before a change in load lubricant directly in a continuously smooth, in particular flat sliding surface itself of the sliding block in the bearing gap is introduced.

A method according to claim 1 or 2, wherein the lubricant from the pressure source is supplied to the pivot bearing of the crank pin and the inner channel system of the sliding block at a second pressure which is below the first pressure in the lubricant layer of the bearing gap which is subject to higher loads.

Method according to one of claims 1 to 4, in which the internal circuit between the two bearing gaps (S _a , S _b ) is essentially closed and the leakage losses from the bearing gaps are minimized.

6. Movement converter for a reciprocating piston machine with a loop-shaped frame (7) which is connected to piston rods (5, 6) of the reciprocating piston machine for the execution of linear alternating movements and has two opposite slide bearing surfaces (112) in the interior of the frame which extend transversely to the direction of the linear alternating movements , between which a sliding block (8) is slidably arranged and guided, in which the crank pin (9) of a rotatably mounted crankshaft (10) is mounted, in which a predetermined play (S) is provided, which is dimensioned such that the sliding block (8) compared to the frame (7) in the direction of the linear alternating movements and depending on the changes of direction and the

Load changes can perform a pendulous relative movements, and in which the two slide bearing surfaces (82, 83) of the slide block (8) are connected to one another via a channel system (97, 98) in the slide block (8) in such a way that, depending on the load changes of the two slide bearing gaps Lubricant can be forcibly transferred from the higher loaded gap into the lower loaded gap.

7. Motion converter for a reciprocating piston machine with a loop-shaped frame (7) which is connected to piston rods (5, 6) of the reciprocating piston machine for carrying out linear alternating movements and in

Interior of the frame has two opposite slide bearing surfaces (112) which extend transversely to the direction of the linear alternating movements, between which a sliding block (8) is slidably arranged and guided, in which the crank pin (9) of a rotatably mounted crankshaft (10) is mounted, and with an external lubricating oil system that works with a pressure source and with the

Rotary bearing (43,93) of the crank pin (9) and the two sliding bearing columns between sliding block (8) and frame (7) is connected, in which a predetermined play is provided between frame (7) and sliding block (8) in the direction of the linear alternating movement , which is dimensioned so that the sliding block (8) relative to the frame (7) in the direction of the linear

Alternating movements and depending on the changes of direction and the load changes can pendeiform relative movements, and in which the two sliding bearing surfaces (82,83) of the sliding block (8) via a bore system (97,98) in the sliding block (8) are connected so that the bearing load less in each case in addition to the lubricating oil from the external

Lubricating oil system (45,46) additional lubricating oil can be fed from the higher loaded bearing gap to build up a damping buffer and sliding layer in the bearing gap (S _a ) which is then more heavily loaded.

8. Movement converter according to claim 6 or 7, characterized in that the two bearing gaps limiting slide bearing surfaces (112,82,83) of frame (7) and sliding block (8) are continuously smooth, in particular without depressions or grooves, and the mouths of the inner

Bore system (97,98) in the sliding block (8) are provided directly in the sliding surfaces (82,83) of the sliding block (8).

9. Motion converter according to one of claims 6 to 8, characterized in that approximately in the center of a bearing recess (93) for the crank pin (9)

The sliding block (8) has a circumferential groove (95) which connects the bores (97) opening in each of the sliding bearing surfaces (82, 83) of the sliding block (8) to form a closed internal lubricant exchange system.

10. Motion converter according to claim 9, characterized in that the channel system (45, 46) connected to the pressure source to the internal lubricant exchange system (95, 97, 98) in the region of the inner circumferential groove (95) of the bearing bore (93) for the Crank pin (9) is connected.

11. A motion converter according to claim 10, characterized in that the crank pin (9) itself has a circumferential groove or a bearing shell (43) receiving the crank pin (9) has an inner circumferential groove (71) with which the feed bore (46) in the crank pin (9 ) of the outer lubricating oil system and the inner circumferential groove (95) in the bearing bore (93) - if necessary via openings (71) in the bearing shell (43a, 43b) - are directly connected in terms of flow.

12. Movement converter according to claim 6 or 7, in which for lateral guidance of the sliding block (8) in the frame (7) both parts have lateral guide surfaces (84, 85; 127, 128) which cooperate in pairs to form guide gaps, characterized in that the Connect the guide column directly to the slide bearing column and its width (S2) is significantly smaller than the width (S1) of the slide bearing column.

13. Movement converter according to claim 6 or 7, characterized in that the respective end regions of the slide bearing surfaces (82, 83) of the slide block (8) on projections (88, 89) of the slide block (8) pointing in the sliding direction and elastically yielding to a limited extent. are provided.

14. Movement transducer according to claim 6, 7 or 9, characterized in that in the sliding block at least four of a circumferential groove (95) of a bearing bore (93) substantially radially extending channels (97) are present, which are approximately centrally between the longitudinal sides of the sliding block (8) open into the sliding surfaces (82,83).

15. Motion converter according to claim 14, characterized in that the bore mouths substantially in the region of the two outer thirds

- measured in the sliding direction (z) - the sliding surfaces (82,83) of the sliding block (8) lie.

16. Movement converter according to claim 14 or 15, characterized in that the radial bores (97) in the circumferential groove (95) of the bearing bore (93) open at substantially the same circumferential intervals.

17. Movement converter according to one of claims 6, 7 or 14 to 16, characterized in that the holes (97) are approximately at right angles

Branch holes (98) converge towards each other towards the sliding surface.

18. Movement transducer according to claim 17, characterized in that a mouth cross-section of the inner bores (98) is larger than a mouth cross-section of the outer

Hole mouths (97).

19. Transducer according to claim 6 or 7 or method according to claim 1 or 2, wherein the sliding surfaces (82,83) of the slider (8) are spherical in the center.