DE102012224399B4 - Shifting/tilting of the bearing points to avoid edge supports and wear on plain bearings - Google Patents

Abstract

Sliding bearing (1) for the sliding bearing of a body (5), e.g. B. a shaft, comprising: a plain bearing body (6), a plain bearing space (2) formed within the plain bearing body (6), in which the body (5) can move, e.g. rotate, a first of or on an inner wall of the plain bearing space ( 2) formed area, which forms a first bearing point (3) for the body (5) and at least one second area formed by or on an inner wall of the sliding bearing space (2), which forms a second bearing point (4) for the body (5), wherein the first area and the second area are spaced apart from one another in the direction of a longitudinal axis (L2) of the plain bearing space (6), wherein a central longitudinal axis (L3, L4) of the first and/or the second area is relative to the central axis (L2) of the plain bearing space ( 2) has an eccentricity (E3, E4) or is inclined, the degree of eccentricity (E3, E4) or an angle of inclination being dependent on a known maximum dynamic deformation and/or tilting of the body (5) during an operational Movement of the body (5) in the plain bearing (1), characterized in that the direction of the eccentricity (E3, E4) or the inclination of the longitudinal center axes (L3, L4) of the first and/or second bearing point (3, 4) corresponds to the direction of the Deformation and / or tilting of the body (5) is opposed.

Description

The invention relates to a plain bearing for the plain bearing of a body with a plain bearing body, a plain bearing space formed in the plain bearing body in which the body can rotate, for example. The slide bearing space has a first area formed by or on an inner wall of the slide bearing space, which forms a first bearing point for the body, and at least a second area formed by or on the inner wall of the slide space, which forms a second bearing point for the sliding body, with the first Area are spaced from each other from the second area in the longitudinal direction of the plain bearing.

Due to the driving forces, a shaft held in a slide bearing, e.g. of a fuel pump, is tilted within the existing bearing clearances. This misalignment leads to edge wear and, as a result, to increased wear within the plain bearing, which leads to greater maintenance and repair costs. Due to the misalignment of the shaft, increased wear can also occur, for example, on a nub or on a piston drive.

There are known solutions to reduce wear on the plain bearing. For example, the manufacturing tolerances are reduced in order to avoid additional coaxiality errors from one bearing point to the other. Alternative suggestions include the formation of flexibly suspended bearing points by accommodating the bearing in a spherical shell, reducing the housing rigidity through material cutouts, using materials with a lower modulus of elasticity, or convex shaping of the shaft surface. Most of these solutions have the disadvantage that they increase the unit costs and/or make the plain bearings larger than necessary.

DE 923 631 B discloses a plain bearing for a shaft, the running surfaces of which can be automatically aligned with one another during operation, the plain bearing being designed to be flexible in such a way that it can follow an adjustment angle of the shaft during operation.

DE 198 06 839 A1 describes a bearing arrangement of a machine with a stator, a rotor and the rotor at both ends of the stator overlying bearings each on a machine plate of the stator. The bearings are arranged in circular disks eccentrically to the center of the circular disk. The circular discs can be set to different rotational positions relative to the machine shields.

DE 21 10 448 A discloses a self-aligning fastener in which a position of a shaft is stabilized by plastic deformation of a bearing.

It is an object of the invention to create a possibility of mounting for a plain bearing which counteracts tilting of the body mounted in the plain bearing.

This object is achieved by a bearing arrangement or a sliding bearing according to claim 1. Advantageous configurations are the subject matter of the dependent claims.

The invention relates to a bearing arrangement or a plain bearing for the plain bearing of a body, such as a shaft, in particular the shaft of a fuel pump of an internal combustion engine. The plain bearing comprises a plain bearing body and a plain bearing space formed in the plain bearing body, in which the body can rotate, for example.

The plain bearing space has a first area formed by or on an inner wall of the plain bearing space, which forms a first bearing point for the body, and at least a second area formed by or on the inner wall of the plain bearing, which forms a second bearing point for the body.

Formed by the inner wall of the sliding bearing space means that the bearing point is formed in one piece with the bearing point from the same material. The area forming the bearing point may protrude from the rest of the inner wall and/or be specially machined, e.g. polished. The area of the bearing point can also have a coating that serves to improve the sliding properties and/or the hardness; the area can also be hardened.

Formed on an inner wall of the plain bearing means that the bearing point is a separate or extra part, preferably made of a material that differs from that of the plain bearing body and has properties such as hardness and surface finish that serve to optimize the bearing. This separate part is firmly connected to the inner wall of the slide bearing space, e.g. pressed into a groove in the inner wall, whereby the part can be cold-treated beforehand and after being pressed in and heated firmly clamped in the groove.

The plain bearing housing or the plain bearing body preferably consists of at least two plain bearing body part shells, which together form the plain bearing body. The partial shells can have centering holes and centering pins on their respective connection sides in order to guarantee an exact connection of the flanges, as well as since Lich molded tabs with holes to connect the partial shells, for example by means of screws and form the plain bearing body.

According to the invention, a longitudinal center axis of the first and/or second area is inclined relative to a longitudinal center axis of the plain bearing space of the plain bearing body, or one or both longitudinal center axes of the two areas have/are eccentric to the longitudinal center axis of the sliding body space.

The first and/or second area can have a diameter that is larger, preferably significantly larger, than a diameter of the body section of the body guided in the plain bearing space, which extends into or through this area of the plain bearing space. This means that a custom-fit design, in which the inner diameter of at least the bearing points of the body in the plain bearing space essentially corresponds to the outer diameter of the body in the area of the bearing points, is deliberately dispensed with, which, due to the generous tolerance dimensions, leads to a reduction in the manufacturing costs for the plain bearing can lead. The deliberately set bearing offset or the deliberately set inclination should bring about an optimal, preferably flat impact or contact of the shaft on/to the bearing points, as well as an optimized alignment of the body under operating load when power is transmitted to another component, e.g. an optimized alignment a cam surface to a roller follower.

If the longitudinal center axes of both bearing points each have an eccentricity to the longitudinal center axis of the slide bearing space, the two eccentricity dimensions can be the same size or different sizes, preferably the size of both eccentricities is the same. In the case in which the longitudinal center axes of the two bearing points are inclined to the longitudinal center axis of the plain bearing space, the angles of inclination of both bearing point longitudinal center axes can be the same or different, preferably they have the same angle of inclination. The two longitudinal central axes of the bearing can lie on a common line or on lines running parallel to one another.

In addition, the eccentricity of the first bearing point can be designed in a different direction relative to the longitudinal center axis of the plain bearing space than the eccentricity of the second bearing point. This means that if the longitudinal center axis of the plain bearing space is defined as the y-axis, the longitudinal center axis of the first bearing point can have a positive x-value and the second bearing point can have a negative x-value, with the longitudinal axes of the bearing points being essentially parallel run to the longitudinal center axis of the plain bearing space.

The extent of the eccentricity and/or the inclination of the longitudinal center axes of the bearing points depends on a maximum dynamic deformation and/or tilting of the body during operation, that is to say when it moves in the plain bearing. It can already be calculated during the design of the plain bearing, since the operating forces acting on the body can be determined in terms of direction and amount, which means that a future direction of possible body tilt and possible body deflection can be predicted.

The direction of the eccentricity and/or the inclination of the longitudinal center axes of the first and/or second bearing point is opposite to the direction of the deformation and/or tilting, so that the body is automatically erected during operation in the plain bearing space due to the geometry of the sliding space, i.e. at least in the direction of its optimal position in the plain bearing space is forced and/or maintained.

This means that the body in the plain bearing, at least in the operating state, i.e. when the body is moving in the plain bearing space at the preferred operating speed, lies flat against the bearing points, so that wear on the body in the area of the bearing areas, e.g. by edge supports, can at least be reduced. The wear and tear of the bearing areas themselves can also be advantageously reduced as a result, which leads to a reduction in the maintenance effort for the slide bearing, longer service life for the bearing points and the body, and thus to reduced costs.

The body can preferably be a camshaft or a shaft of a preferably high-speed pump, e.g. the shaft of a fuel pump for an internal combustion engine.

Throughout the specification and claims, the term "a" or "an" is not intended to be limiting. If this term is meant as a number, this will be clearly identified in the description and claims by terms such as "a single one". That is, the term "a" in this specification may, but need not, be read as "at least one."

The invention is explained in more detail below using an exemplary embodiment with the aid of figures. The embodiment shown in the figures is an exemplary embodiment of the invention, to which the invention is not limited. Features essential to the invention that can only be found in the figures belong to the scope of the invention and can advantageously develop the subject matter of the invention.

• 1 Gleitlager, mit im Betriebszustand gekippter Nockenwelle
• 2 Ausführungsbeispiel eines erfindungsgemäßen Gleitlagers, mit im Betriebszustand optimiert geführter Nockenwelle

The figures show in detail:

• 1 Plain bearing, with camshaft tilted during operation
• 2 Exemplary embodiment of a plain bearing according to the invention, with a camshaft guided in an optimized manner in the operating state

the 1 shows a longitudinal section through a layer arrangement of a plain bearing 1 or a plan view of a bearing housing half-shell or a plain bearing body half-shell 6 with a plain bearing space 2 in which two bearing points 3 and 4 are formed. A body 5, here a shaft 5a with a cam 5b, is guided in plain bearing space 2. Due to the dynamic forces acting on the body in the operating state, that is, with the shaft 5a rotating and the cam 5b rotating with it, the body 5 is tilted in the plain bearing space 2 . The main thing is driving forces at the free end of the shaft, introduced by belt, chain or gear drive.

This tilting leads to point or linear supports of the body 5 on edges 3a, 4b of the two bearing points 3, 4 and thus to greater wear and tear on both the bearing points 3, 4 and on the body 5 in the area in which the body 5 is supported at the bearing points 3, 4; especially to edge beams on the shaft 5.

In the bearing arrangement 1 shown or in the plain bearing 1 shown, the longitudinal center axes L2, L3, L4 of the first bearing point 3, the second bearing point 4 and the plain bearing space 2 lie on a common line. The inside diameter D3 of the first bearing point 3 is smaller than the inside diameter D4 of the second bearing point L4.

In the plain bearing 1 shown, the bearing points 3, 4 are not formed in one piece with the bearing housing or plain bearing body 6, but are made of a different, e.g. harder material than the plain bearing body 6. For example, the plain bearing body 6 can be made of cast steel, while the bearing points 3 , 4 are made of high-quality and/or hardened steel. In the case of the diesel fuel high-pressure pump, composite bearings with plastic running surfaces are used for 3 and 4.

the 2 shows a plain bearing 1 according to an embodiment of the invention, in which the longitudinal center axes L3, L4 of the bearing points 3, 4 are arranged eccentrically to the longitudinal center axis L2 of the plain bearing space 2. The degree of eccentricity E3 of the longitudinal center axis L3 of the first bearing point 3 to the longitudinal center axis L2 of the plain bearing space 2 corresponds in this embodiment to the degree of eccentricity E4 of the longitudinal center axis L4 of the second bearing point 4 to the longitudinal center axis L2 of the plain bearing space 2.

The body 5, as in the 1 has a shaft 5a and a cam 5b, is now firmly pressed onto the bearing points 3, 4 in the operating state in the event of a dynamic deformation and/or tilting tendency and can no longer tilt due to the bearing points 3, 4 arranged eccentrically to the longitudinal center axis L2.

In the exemplary embodiment, the degree of eccentricity E3, E4 of the two bearing point longitudinal central axes L3, L4 is the same, as is the inner diameter D3, D4 of the two bearing points 3, 4.

Claims (8)

Sliding bearing (1) for the sliding bearing of a body (5), e.g. B. a shaft, having: a plain bearing body (6), a plain bearing space (2) formed within the plain bearing body (6), in which the body (5) can move, eg rotate, a first of or on an inner wall of the plain bearing space ( 2) formed area which forms a first bearing point (3) for the body (5) and at least a second area formed by or on an inner wall of the plain bearing space (2) which forms a second bearing point (4) for the body (5). , wherein the first area and the second area are spaced apart from one another in the direction of a longitudinal axis (L2) of the plain bearing space (6), wherein a central longitudinal axis (L3, L4) of the first and/or the second area is relative to the central axis (L2) of the plain bearing space (2) has an eccentricity (E3, E4) or is inclined, the extent of the eccentricity (E3, E4) or an angle of inclination being dependent on a known maximum dynamic deformation and/or tilting of the body (5) during an operating condition Gten movement of the body (5) in the plain bearing (1), characterized in that the direction of eccentricity (E3, E4) or the inclination of the longitudinal center axes (L3, L4) of the first and / or second bearing point (3, 4) of the direction the deformation and / or tilting of the body (5) is opposed. slide bearing after claim 1 , wherein a diameter (D3, D4) of the first and/or the second area is larger than a diameter of the body portion which extends into or through this/n area/s. Plain bearing according to one of the two preceding claims, wherein the magnitude of the eccentricity (E3) of the first bearing point (3) is the same as or different from the eccentricity (E4) of the second bearing point (4). Plain bearing according to one of the preceding claims, wherein the eccentricity (E3) of the first bearing point (3) relative to the central longitudinal axis (L2) of the plain bearing space (2) is formed in a different direction than the eccentricity (E4) of the second bearing point (4). Plain bearing according to one of the preceding claims, wherein the bearing points (3, 4) are formed in one piece with the plain bearing (1) from the same material or the bearing points (3, 4) consist of a different material than the plain bearing (1) and with the Inner wall of the plain bearing (1) are firmly connected. Plain bearing according to the preceding claim, wherein the material of the bearing points (3, 4) is harder than the material from which the plain bearing body (6) is formed. Plain bearing according to one of the preceding claims, wherein the body (5) in the plain bearing (1) lies flat against the bearing points (3, 4) in the operating state, so that wear of the body (5) by e.g. edge supports in the area of the bearing points (3, 4 ) is reduced. Plain bearing according to one of the preceding claims, in which the body (5) is a camshaft or a shaft of a preferably high-speed pump, e.g. a fuel pump for an internal combustion engine.

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