WO2015144137A1

WO2015144137A1 - Valve device and slide bearing assembly

Info

Publication number: WO2015144137A1
Application number: PCT/DE2015/100122
Authority: WO
Inventors: Markus Schneider; Dirk Wehner; Sabine Gold
Original assignee: Technische Universität Dresden
Priority date: 2014-03-24
Filing date: 2015-03-24
Publication date: 2015-10-01
Also published as: DE112015001449A5; DE102014004524A1

Abstract

Disclosed is a valve device for metering volumetric flow, said device facilitating a load-dependent supply resistance and having two discrete switching positions. A switching pressure for transferring a switching element of the valve device from its idle position into its working position can be set independently of the supply pressure of said element. Also disclosed is a slide bearing assembly comprising at least one valve device of this type.

Description

Valve device and plain bearing

The invention relates to a valve device according to the preamble of patent claim 1 and a plain bearing.

Slide bearings and in particular radial plain bearings are used in many ways. The hydrodynamically lubricated radial plain bearing has long been known. In the hydrodynamically lubricated radial bearing created by an eccentric shaft displacement in the bearing shell and a relative movement between the sliding surfaces of the shaft and bearing shell, a hydrodynamic lubricating film pressure in the narrowing bearing gap, which counteracts the bearing load, thus preventing contact between the shaft and bearing shell and thus wear on the shaft and bearing shell avoids.

In order to compensate for the lubricant loss in the bearing gap, which arises because in the range of high lubricant film pressures lubricant exits at the bearing edges, hydrodynamic bearings are usually equipped with a lubricant supply device, with a pressure substantially lower than the average lubricating film pressure, the lubricant in transported the bearing gap. In order to make this possible, at least one bearing pocket is arranged in the region of the bearing gap, in which the latter widens again and, as a result, a low pressure prevails. Such a hydrodynamic lubricant device comprises at least one lubricant pump and connecting lines which connect the lubricant pump with the bearing pockets.

As a rule, this device is protected by a pressure relief valve from destruction by excessive pressure, can drain over the excess lubricant quantities. A separate distributor for distributing the lubricant to the bearing pockets is not required. The lubricant flows on the path of least resistance in the bearing gap. The great advantage of the hydrodynamically lubricated radial plain bearing is the low technical complexity and reliable operation of the self-regulating hydrodynamic pressure build-up. Another advantage is that the bearings can withstand very high shock loads for a short time without destruction. In the case of shock loads, the compression of the bearing gap briefly creates an additional pressure in the lubricating film which prevents contact between the bearing shell and the shaft. A disadvantage of the hydrodynamic plain bearing is that a rotation of the shaft is required to produce the required hydrodynamic pressure build-up in the bearing gap. When starting and at low speeds, it comes to solid contact between the shaft and bearing shell and thus short-term wear. To eliminate this disadvantage, hydrostatic radial plain bearings have been developed. Here, the required lubricant pressure in the bearing gap is generated by at least one high pressure pump outside the camp. Distributed over the circumference of the bearing several mostly large-area bearing pockets are arranged, which are connected to the lubricant supply device. Mainly acting in the bearing pockets hydrostatic pressure provides the counterforce against the bearing load, thus avoiding contact between the shaft and bearing shell. So that the lubricant flow generated by the high-pressure pump does not flow via the path of the least resistance exclusively into the lubrication pockets with the largest bearing gap thickness, a distributor for the targeted distribution of the lubricant flows is required. Such a hydrostatic lubrication device has at least one high-pressure pump, a distributor for distributing the lubricant flows to the various bearing pockets and connecting lines.

The advantage of the hydrostatic radial plain bearing is that even with minimal rotational movements or even when the shaft is stationary, a lubricating film of finite thickness can be maintained and so contact between the shaft and bearing shell and thus wear in all operating conditions can be avoided.

Required, however, is a technically complex lubricant supply and for the external generation of the lubricant pressure during the entire operating time additional energy is required. While virtually no wear occurs in the actual camp, this does not apply to the peripheral utilities. Since the peripheral utilities are constantly under high pressure, they determine the reliability and service intervals of the bearing.

A combination of a hydrodynamic bearing with a hydrostatic bearing is shown for example in DE 10 2009 012 398 B4.

A very common hydrostatic bearing provides to carry out a valve device in the form of a capillary valve, which acts as a static throttle. The disadvantage, however, is that the capillaries cause high flow rates in unloaded storage bags due to their constant resistance characteristics, resulting in large volume flow losses and a strong Ölerwärmung in the hydrostatic bearing. A pressure supply and an oil cooling must be dimensioned accordingly consuming. Furthermore, it is known to dose the volume flow in a hydrostatic bearing pocket load-dependent by means of a progressive-quantity regulator (PM controller). However, for a stable operation of the PM controller, a certain ratio between minimum and maximum volume flow is required, which still causes high volume flow losses in unloaded storage bags. The maximum flow rate and thus the highest stiffness of the storage bag is only reached at pocket pressures that are almost as high as the supply pressure. However, this rigidity is preferred even with a low-loaded storage bag. In addition, the resistance characteristic of the PM controller is set to a fixed supply pressure, a variation of the supply pressure affects the characteristics and thus the performance negatively.

Furthermore, it is known to carry out a hydrostatic bearing in the form of a diaphragm valve. The diaphragm valve allows continuous open and close control, but is due to its membrane construction relatively susceptible to interference and maintenance-intensive.

The object of the invention is to provide a valve device for volume flow metering, by means of which the volume flow is metered into a hydrostatic bearing pocket depending on the load of the storage bag. Furthermore, it is an object of the invention to provide a robust and low-maintenance slide bearing.

This object is achieved by a valve device having the features of patent claim 1 and by a plain bearing having the features of patent claim 9.

A valve device according to the invention for metering a volume flow has a housing which has a supply connection and a working connection, and an element arranged in the housing for setting a flow cross section between the supply connection and the working connection. According to the invention, the element is designed as a slide which minimizes the flow cross section in a rest position and maximizes the flow cross section in a working position. The slider is biased by at least one biasing member in the rest position and can be transferred via a switching pressure in the working position. The switching pressure is adjusted by means of a biasing force.

The valve device according to the invention is in its preferred embodiment, a mechanical slide valve for the flow control or flow control hydrostatic sliding bearings. It's almost a pressure balance in Form of a pressure-controlled slide valve with two discrete switching positions, which is set independently of its supply pressure. In the assembled state, for example when integrating the valve device in a sliding bearing, e the actuation of the valve device via a difference between a pressure in the respective bearing pocket and the switching pressure defined by the at least one biasing element. A preferred biasing element is a spring and in particular a spiral spring.

A load of the sliding bearing causes a deflection of a bearing shaft, which results in an increase in pressure in each loaded bearing pocket. When unloaded storage bag, the slide is in its rest position and the valve device is virtually closed. The flow cross-section is minimized and only a small volume flow flows into the bearing pocket in order to reduce cavitation in the bearing gap. However, if the pocket pressure increases to the set switching pressure, then the slider moves against its biasing force or spring force from its rest position to its working position. The valve device is opened and set the maximum flow cross-section. There is an increase in the volume flow in the bearing pocket, so that the required load capacity is safely established. By means of the valve device according to the invention, therefore, a volume flow can be metered into a hydrostatic bearing pocket depending on the load on the bearing pocket. A loss volume flow in an unloaded storage bag is minimized by a high feed resistance. When the bearing bag is loaded, the supply resistance is reduced, the volume flow increases and the stiffness of the bearing pocket is increased.

In one embodiment, the slider has variable notches defining the flow area. As a result, the volume flow in the respective storage bag is precisely defined. The notches are arranged on the outer circumference side and thus easy to produce in terms of production technology in the slide. "Variable" means that the notches are cross-sectionally extended from their beginning or beginning in the direction of their end.

Preferably, the notches extend in the longitudinal direction or sliding direction of the slider, wherein a maximum slide stroke is limited to the notch lengths. As a result, a back pressure in the region of the notch beginnings can be prevented.

Advantageously, the at least one biasing element engages a slider via a spring plate, which is in operative connection with the slider via a roller bearing. Due to the roller bearing friction losses between the at least one em biasing element and the slider are minimized.

Preferably, the spring plate is connected via a central ball with the slider in operative connection. As a result, component or assembly tolerances and alignment tolerances between the spring plate and the slide can be compensated. For example, the spring plate can thereby be tilted relative to the slide, without affecting the functioning of the valve device. The working position can be easily formed if it is limited by an emergence of the spring plate on a housing section.

Preferably, in the direction of the volume flow downstream of the slide, a check valve is provided which blocks when a blocking pressure which is greater than the switching pressure is exceeded in the direction of the supply connection. The check valve prevents backflow of the lubricant from the respective bearing pocket during load peaks, which increases the rigidity of the bearing pockets at highly dynamic loads. In addition, it allows a hydrodynamic pressure build-up during a wave rotation. Advantageously, the check valve is biased in an open position, for example spring-biased, so that when the pressure drops below the backflow is ensured. In the installed state of the valve device in a plain bearing, the check valve is thus positioned between the slide and the respective bearing pocket. The functioning of the quasi-pressure scale is not hindered by the check valve.

The valve device can be made compact with the check valve, who n the check valve is structurally integrated into this. For example, the check valve may be inserted into the working port, wherein it preferably limits the rest position of the slide.

A plain bearing according to the invention is provided with at least one valve device according to the invention. Such sliding bearing, for example, for the storage of ship propeller shafts, is characterized by a high load capacity, high robustness against load peaks, reduced maintenance, a compact design and low energy consumption.

Other advantageous embodiments of the invention are the subject of further subclaims. In the following, preferred embodiments of the invention will be explained in more detail with reference to highly simplified schematic illustrations. Show it:

FIG. 1 shows a schematic structure of a preferred plain bearing,

Figure 2 is a first schematic detail of an inventive

Valve device of Figure 1,

Figure 3 shows an integration of the valve device according to the invention in the

Slide bearing in longitudinal section,

Figure 4 is a detail view of the valve device according to the invention in

Longitudinal section

Figure 5 is a volume flow pressure diagram and

Figure 6 is an alternative schematic representation of the invention

Valve device.

For reasons of clarity, not all the elements shown are provided with a reference numeral in FIG. In the same effect or the same constructive elements, an element is representative of all similar elements, each provided with a reference numeral. Figure 1 shows a basic structure of a plain bearing 1 according to the invention, designed as a radial sliding bearing. The sliding bearing 1 for supporting a shaft 2, for example a ship propeller shaft, in a bearing shell 4 has a hydrodynamic lubrication device 6 and a hydrostatic lubrication device 8. The lubrication devices 6, 8 are in fluid communication with a multiplicity of bearing pockets 10 which are uniformly distributed over the circumference of the bearing Bearing shell 4 are introduced into this.

The hydrodynamic lubrication device 6 has a low-pressure pump 14 driven by an electric motor 12, with the aid of which a lubricant can be conveyed from a tank 16 via low-pressure lines 18, 20 to, for example, two opposite bearing pockets 10. In order to prevent a backflow of the lubricant from the bearing pockets 10 in the direction of the low pressure pump, a check valve 22 is disposed in the low pressure lines 18, 20 respectively. The low-pressure line 20 extends from the low-pressure line 18, wherein a spring-loaded pressure limiting valve 24 (see FIG. 2) is arranged in an unnumbered tank line between the low-pressure line 20 and the tank 16 to avoid overstressing the hydrodynamic lubrication device 6. The pressure relief valve 24 is optionally piloted in this embodiment. The hydrostatic lubrication device 8 has a high-pressure pump 28 driven by an electric motor 26, by means of which the lubricant can be conveyed from the tank 16 into the bearing pockets 10. For this purpose, the high-pressure pump 28 is connected via a feed line 30 to a multiplicity of parallel supply lines 32, one of which extends to one of the bearing pockets 10. In the area of the bearing pockets 10, a respective valve device 34 is arranged in the supply lines 32. The valve device 34 has a quasi-pressure balance and in particular here, for example, a slide valve 36 for metering a volume flow of a lubricant with a check valve 38 arranged downstream in the direction of the volume flow.

In order to prevent overloading of the hydrostatic lubrication device 8, a spring-loaded pressure relief valve 40 is arranged in an unnumbered tank line between the supply line 30 and the tank 16. The pressure relief valve 40 is optionally piloted in this embodiment.

FIG. 2 shows a first schematic individual representation of the valve device 34 according to the invention. The slide valve 36 has two discrete switch positions I, II, namely a spring-biased rest position I and a working position II. In addition, the slide valve 36 has two ports A, V, namely a pump-side supply port V and a storage pocket side working port A.

In the rest position shown, the volume flow is minimized by the high-pressure pump 28 to the bearing pocket 10 via a throttle 42. In working position II, the volume flow is maximized. For the transfer of the slide valve 36 from its rest position I to the working position II when a switching pressure is exceeded, the valve device 34 has a control line 44, which picks up a control pressure downstream of the slide valve 36 and leads to this.

Downstream of the slide valve 36 and also downstream of the control line 44, the check valve 38 is integrated into the valve device 34. The check valve 38 has a closing body 46, which is spring-loaded counter to its blocking direction. For clarity, the spring element is not shown in the drawing.

A spring force of the spring element is dimensioned such that a load-dependent switching pressure to the working port A can be reported via the check valve 38 from the bearing pocket 10, with the aid of which the slide valve 36 in the working position II is transferred. When a barrier pressure is exceeded, for example, as a result of peak loads, however, the spring force is overcome and the check valve 38 closes, so that a return flow of the lubricant from the bearing pocket 10 is prevented. Furthermore, in Figure 2, the shaft 2, the tank 16, the high-pressure pump 28, the here pilot-operated and spring-biased pressure relief valve 24, and a bearing pocket 10 are shown and numbered.

As shown in FIG. 3, in a preferred slide bearing 1, the respective valve device 34 is received in sections in a receptacle 47 of the plain bearing 1. The valve means 34 is carried out in a cartridge and has a housing 48, by means of which it is inserted in the receptacle 47, preferably screwed, is. In order to prevent an outer peripheral leakage current along the valve device 34 between the supply port V, the working port A and a tank port T, these ports A, B, T are mutually sealed by outer peripheral seals 50, 52, 54.

To produce a respective fluid connection between the high-pressure pump 28 shown in FIG. 1, the bearing pocket 10 and the tank 16 shown in FIG. 1, fluid lines 32, 56, 58 corresponding to the slide bearing 1 are introduced. The supply connection V and the tank connection T are designed, for example, as bore stars introduced into the housing 48. The working port A is here a radial extension of a longitudinal bore introduced into the housing 48, in which (the extension) the check valve 38 is inserted, preferably screwed, is. About a non-numbered annular seal used in a front side groove of the check valve 38, a leakage flow on the outer peripheral side of the check valve 38 is prevented.

As numbered in Figure 4, the longitudinal bore passes through the housing 48 in the longitudinal direction and has, in addition to the Arbeitsanschlussseitigen or front extension a rear radial extension 62 and a radially opposite to the extensions 62 tapered central portion 64. The rear extension 62 forms a receiving space in the an insert 66 is provided for providing a biasing means for biasing a slider 68 into the rest position I, preferably screwed in. The slider 68 is slidably guided in the middle portion in the longitudinal direction of the housing 48 between the biasing device and the check valve 38. The insert 66 has a spring space 70, which is introduced into its front end face 72 and a spring 74 of the biasing device is inserted. For lateral stabilization of the spring 74, the spring chamber 70 is radially tapered in the region of its bottom 76. Their formed by the spring chamber 70 as an annular surface end face 72 forms a mechanical stop for a spring plate 78 of the biasing means and thus a Schieberhubbegrenzung or the working position 1 1 of the slider 68th

For discharging leaked oil that has penetrated into the spring chamber 70, the insert 66 is provided with a bore star 80, which in the mounted state is in overlap with the tank connection T. In order to prevent a leakage flow on the outer peripheral side along the insert 66, in an outer circumferential groove of the insert 66, a sealing ring 82 is used, which is sealingly in abutment with an opposite inner peripheral portion of the rear extension 62.

The biasing device is used for biasing the slider 68 in its rest position I. For this purpose, the spring 74 is supported on the bottom of the spring chamber 70 and engages on the spring plate 78 on the slider 68 at. To guide the spring 74 at its free end of the spring plate 78 has a rear projection 84 which is partially encompassed by the spring 74. The projection 84 surrounding annular surface 86 is in the working position 1 1 on the end face 72 of the insert 66, whereby a slide stroke is limited from its rest position I.

Preferably, the spring plate 78 is supported via a rolling bearing on the slider 68. The roller bearing comprises in the embodiment shown here, a ball as a rolling element, which is positioned centrally on the longitudinal axis of the housing 48 and partially in each case a front-side recess 88, 90 of the spring plate 78 and the slider 68 is immersed. The recesses 88, 90 are formed in the opposing end faces, that between the spring plate 78 and the slider 68, an axial gap 92 is formed, for example, allows relative tilting movements of the spring plate 78 to slide 68.

The slider 68 is a cylindrical member, in the outer circumference of which variable notches 94 are uniformly distributed. In principle, the notches 94, in cooperation with a circumferential housing edge 96, the longitudinal direction of the slider 68 and open in the direction of the volume flow until they emerge frontally at the front end of the slider 68. So you are in the direction of the dosing Volume flow cross-section widened. They have an axial extent such that they begin in the rest position I of the slide 68 in the region of the supply connection V. In this case, the slide 68 is located at the front end, from which the notches 94 exit the front side, to the check valve 38 at. In the working position II, in which the slider 68 is lifted from the check valve 38, the notches 94 are provided with a correspondingly enlarged notch cross-section in the region of the supply connection V.

With reference to Figure 5, the operation of the valve device 34 according to the invention will be explained. It is expressly pointed out that the given diagram values are not limiting, but are only to be understood as examples.

At a minimum bearing pocket pressure p ₆ , the flow cross section in the direction of the bearing pockets 10 is minimized. The slider 68 is thus in its rest position I, in which a minimum volume flow 98 is formed. As soon as a bearing pocket pressure exceeds a switching pressure 100 of the spring 74, the slide 68 is transferred to its working position and the flow cross-section is maximized (maximum volume flow 102). After a drop in the bearing pocket pressure p ₆ , the slider 68 moves back to its rest position I and the flow cross section is again minimized. In the embodiment shown, a system pressure 104 of up to about 220 bar is possible before the check valve 38 blocks. The spring force essentially determines the switching pressure 100, whereas the spring constant of the spring 74 substantially determines the curve between the minimum volume flow 98 and the maximum volume flow 102.

According to the invention, a metering of the volume flow Q ₆ into the here hydrostatic bearing pocket 10 is dependent on the respective pocket load. A loss volume flow (minimum volume flow 98) into an unloaded bearing pocket 10 is minimized by a high inlet resistance (throttle 42 or variable notches 94 with housing edge 96). When loading the previously unloaded bearing pocket 10, the inlet resistance is reduced (increased flow cross section of the notches 94). The maximum volume flow 102 is formed and the rigidity of the bearing pockets 10 which are now loaded is increased. At load peaks, the check valve 38 locks and a return flow of the lubricant from the bearing pocket 10 to the supply port V is prevented.

FIG. 6 shows an alternative schematic representation of the valve device 34 according to the invention. Essentially a difference from the illustration shown in FIG. 2, in FIG. 6, a throttle 42 of the valve device 34 is not symbol I but as a notch-housing edge combination 94, 96 shown. As a further significant difference, the spring 74 is clamped in the spring chamber between the bottom 76 of the spring chamber 70 and the slide 68, shown in its rest position I. The other reference numerals used in Figure 6 correspond to the same structural elements as in Figures 2, 3 and 4, so that reference is made to avoid repetition to the explanations to these figures.

Disclosed is a valve device for volume flow metering, which allows a load-dependent inlet resistance and two discrete switching positions, wherein a switching pressure for transferring a switching element of the valve device is adjustable from its rest position to its working position regardless of its supply pressure, and a sliding bearing with at least one such valve device.

Plain bearing

wave

bearing shell

hydrodynamic lubrication device

hydrostatic lubrication device

bearing pocket

electric motor

Low pressure pump

tank

Low-pressure line

check valve

Pressure relief valve

electric motor

high pressure pump

supply

Supply line / fluid line

valve means

Quasi-pressure balance / slide valve

check valve

Pressure relief valve

throttle

control line

closing body

admission

casing

Peripheral seal

pusher

line section

check valve

fluid line

Bullet

extension

middle section

commitment

pusher

spring chamber

front

feather

ground

spring plate

bore star

sealing ring

head Start 86 ring surface

88 deepening

90 deepening

92 axial gap

94 notch

96 case edge

98 minimum flow rate

100 switching pressure

102 maximum flow rate

104 system pressure

I rest position

II working position

V supply connection

A work connection

T tank connection

Claims

claims

1 . Valve means (34) for metering a volumetric flow, comprising a housing (48) having a supply port (V) and a working port (A), and having an element (68) disposed in the housing (48) for adjusting a flow area between the Supply connection (V) and the working connection (A), characterized in that the element (68) is a slide which minimizes the flow cross-section in a rest position (I) and in a working position (1 1) the flow cross-section is maximized at least one biasing element (74) is biased in the rest position (I) and via a working port side switching pressure, which is adjusted by means of a biasing force in the working position (1 1) can be transferred.

2. Valve device according to claim 1, wherein the slide (68) has variable notches (94) for defining the flow cross-section.

3. Valve device according to claim 2, wherein the notches (94) extend in the sliding direction and a maximum spool stroke is limited to the lengths thereof.

4. Valve device according to claim 1, 2 or 3, wherein the at least one biasing element (74) via a spring plate (78) on the slider (68) engages, which is connected via a rolling bearing with the slide (68) in operative connection.

5. Valve device according to claim 4, wherein the spring plate (78) via a central ball (60) with the slide (68) is in operative connection.

6. Valve device according to claim 4 or 5, wherein the working position is limited by a running of the spring plate (78) on a housing portion.

7. Valve device according to one of the preceding claims, wherein in the direction of the volume flow downstream of the slide (68), a check valve (38) is provided, which blocks at a barrier pressure greater than the switching pressure, in the direction of the supply port (V) is exceeded.

8. Valve device according to claim 7, wherein the check valve (38) is inserted into the working port (A).

9. Slide bearing, with at least one valve device (34) according to one of the preceding claims.