DE8909995U1 - Unit for automatic minimum quantity lubrication - Google Patents

Description

Deutsche Tecatemrt GmbH · PO Box 120128 · 4800 Bielefeld 12 AmMetailwerkH Dresdner Bank AG Bielefeld 1 Telephone (0521) 4049-0 Contact No. 2075751 Telex937314tecad BLZ48Q8Ü020 Fax (0521) 4049305 Sparkasse Bielefeld 12 Managing Director: Contact No. 7289804 E Barrie Stephens C. Eng. Bank code 480 501 61 DipL-Ing. Werner J. !rxjenhag Postgiro Hannover 31377-304 Hans G. Brinker Bank code 2S010030 District Court of Bielefeld HRB 7168 S SIEVE COMPANY Yours sincerely, Our drinking Dgtum 206/89-500 18.08.89 Ox-. &iacgr;-&iacgr;&ugr;/Wa Aggregate for ;jtomatis'hen Minimum quantity lubrication

The invention relates to a unit ^for automatic minimum quantity lubrication according to the oil-air lubrication method for high-speed machine elements, e.g. low-accuracy and high-precision rolling bearings with speed characteristics of η χ d ?
1.4&khgr;&Igr;&Ogr; ⁶ or = 2.4 &khgr;&Igr;&Ogr; ⁶ mm x 25 m Min. ~ ^X .

Such devices for lubricating high-speed machine elements with liquid (viscous) lubricants are known according to this method. The lubricating oil is dosed intermittently and volumetrically, conveyed through a mixing chamber into a parallel compressed air flow, through
This is transported along the inner wall of a mixing pipe and then in possibly further channels and via a
Nozzle quasi-continuously finely distributed to the machine element
(&zgr;. B. rolling bearings); each friction point is
At least one oil-air micropump is assigned. In addition to the effect of the compressed air on the lubricant, as a result of
an energy transfer through shear stresses of the compressed air to the lubricating oil in turbulent air-side flow conditions, it has a cooling effect in the bearing point, as well as a sealing air effect, for example in the entire bearing assembly. The lubricant is metered in a KoI-

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Sheet 2 Date 18.08.89

206/89-500

ben micropump, into which the lubricant flows by gradient from the lubricant container via a fine filter on the suction side. The pump is operated by applying compressed air; its piston stroke is mechanically adjustable and thus the dosing quantity. The cycle time of the pressurization of the micropumps can also be adjusted using an electrical control unit; thus, the lubricant delivery per unit of time is determined by varying these two parameters.

(Ordinance: 10 mm /h, quasi-continuous at the lubrication point). The process-based reduction of the lubricant quantity per unit of time reaches its limit where the lubricant transport on the wall of the mixing line breaks off periodically and the release at the lubrication point is discontinuous.

The disadvantages of this design are the adjustment options for the piston stroke of the micropump for the dosing quantity, which always requires a complicated quantity measurement to determine the exact delivery quantity per unit of time, the low compressed air pressure of the piston of the micropump (e.g. with max. 6 bar, as is available in an industrial compressed air network) and thus the restriction of the pumping capacity to low-viscosity lubricating oils, the pressureless supply of the lubricating oil to the micropumps and its filtration, as well as the exclusive use of such a unit for a specific purpose.

Accordingly, the invention is based on the task of avoiding these disadvantages. According to the invention, this is achieved by the following measures:

1. Use of a cost-effective, standard pump from the production program of a system based on the principle of single-line central lubrication, preferably according to the pulse system; the pump can be operated either pneumatically, hydraulically or electrically.

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Sheet 3 Date 18.08.89

No. 206/89-500

2. Use of replaceable metering valves with a constant dosing quantity based on the principle of single-line central lubrication, preferably based on the pulse system; these are screwed into the lubricant-air distributors. They are available at low cost.

3. In the lubricant pressure line, hydraulically connected in parallel, the output for connecting the main line of a normal central lubrication system (interface) is realized.

4. Arrangement of one or more filters on the pressure side for the lubricant-air lubrication, in particular with a very fine filtration of the lubricant.

5. Arrangement in each individual lubricant-air distributor of an adjustable throttle valve for adjusting the compressed air depending on the respective dosing quantity of the metering valves and the flow conditions in the mixing line with a view to quasi-continuous delivery to the lubrication point with an optimal spray pattern.

The hydraulic conversion of the pump's delivery pressure in the metering valve means that significantly higher viscosities of liquid lubricants and even consisted greases (e.g. fluid greases) can be processed using this method. This is due to the significantly higher pressure level of the primary hydraulic lubricant circuit of the entire unit, based on the induction principle, in particular the pulse system, and overcoming the counterpressure of the pneumatic circuit in the mixing zone of the lubricant-air distributor.

A preferred embodiment of the invention is described in detail below with reference to the drawings; they show:

Figure 1 shows a schematic hydraulic-pneumatic circuit diagram of the unit in a construction unit with four lubricant

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Sheet 4 Date 18.08.89

No. 206/89-500

air distributors.

Figure 2 shows the schematic front view of such a unit, whose central lubrication piston pump is pneumatically operated.

Figure 3 shows the hydraulic circuit diagram of a hydraulically operated central lubrication piston pump.

First, let’s look at Figure 1.

When the main switch on of the entire machine for which the lubrication unit (38) is used is activated, the 2/2-way solenoid valve (29) for the compressed air supply for the unit (38) is released and the compressed air flows continuously to the lubrication points via the lubrication point connection (18).

At the same time, the pressure gauge (22) shows the prevailing pneumatic pressure in front of the lubricant-air distributor (13). The compressed air quantity depends on the setting of the reducing valve (21) and the respective throttle valve (17) in the lubricant-air distributor (13). At the same time, the electronic control unit (25) starts. The control unit (25), possibly with a slight time delay, starts the 3/2-way solenoid valve (20) for the compressed air of the central lubrication pump (1), whose delivery unit (46) is actuated by the pneumatic cylinder (3). The hydraulic pressure build-up in the delivery unit (46) switches the 3/2-way control valve (6) of the pump (1) to pass through and a hydraulic delivery effect of the lubricant occurs, combined with a pressure build-up via the pressure line (5) in the entire hydraulic part of the unit (38). At the same time, the electro-hydraulic control elements (8, 12, 43) come into action, the electrical signals of which are fed to the control and monitoring device (25).

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No. 206/89-500

The hydraulic pressure build-up activates the metering valves (14) in the respective lubricant-air distributors (13). Due to their mode of operation according to the single-line central lubrication, in particular according to the pulse method, they meter their constant volumetric metering volume of the lubricant into the mixing zone (15) against the prevailing air pressure. The entire pressure conversion of the lubricant takes place hydraulically at a pressure level of approximately 50 to 100 bar on the primary side. The interchangeability of the metering valves (14) means that different metering quantities can be achieved.

From the mixing zone (15), the permanently escaping compressed air now transports the lubricant from the distributor (13) via the mixing line (16) to the lubrication point connection (18) on the machine to be lubricated. By setting the appropriate air pressure on the reducing valve (21) and in particular individually on the throttle valve (17) of the distributor (13), the lubricant is evenly distributed on the inner wall of the line (16) and is transported quasi-continuously as a lubricant-air mixture via the connection (18) to the lubrication point and reaches the friction point of the machine element to be lubricated.

The absolute cleanliness of the lubricant is of the greatest importance in the oil-air process, which requires a microfilter (9) in the pressure line (5), controlled by a differential pressure switch (43). The lubricant is filtered in a similar way with the filter (10) in the parallel line for central lubrication with the connection (11).

The central lubrication pump (1) has a suction strainer (2) on the suction side, a 3/2-way control valve for building up the lubricant pressure in the pressure line (5) and downstream devices.

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No. 206/89-500

valve (6) with a relief line (7) into the lubricant container (4). This container (4) is designed as an interchangeable container and has an external fastening thread (48). The minimum level of the lubricant in the container (4) is registered by a level switch (24).

The timing of the lubrication, in addition to the control functions, is controlled by a pulse-pause control of the electronic control and monitoring device (25). In particular, various time settings for the lubrication breaks and the opening times of the 3/2-way solenoid valve (20) can be made there; pause symbol (53) and pulse symbol (54).

Figure 2 shows the unit as a structural unit (38) in front view and the arrangement of individual components according to Fig. 1. The lubricant container (4) is screwed via an external fastening thread (48) to the internal fastening thread (50) of the pump bracket (49) on which the central lubrication pump (1) is arranged. The container (4) is in turn protected by a hood (51) which has a viewing slot ' 5 2 ^ on its side:

Figure 3 shows the central lubrication pump (31) operated by a hydraulic cylinder (i2) with its delivery unit (46). This cylinder (42) is connected by a hydraulic line (33) to the 3/2-way solenoid valve (32) located outside the unit (38), which is part of the hydraulic circuit of the entire machine. The lubricant pressure line is indicated in (5).

In Figure 4, the central lubrication pump (34) operated by an electric motor (39) is shown with the outlet of the lubricant pressure line (5).

A simplified control option not shown

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the pneumatically operated central lubrication pump (1), consists in integrating an electronic module into the electrical device plug for the magnet of the 3/2-way solenoid valve (20), which contains the pulse-pause control. Another possibility is to have all control and monitoring functions for lubrication carried out by the microprocessor of the NC machine that is to be lubricated; the only exception is the visual pressure displays by means of pressure gauges (12, 22); in this case, the electronic control and monitoring device (25) is not required. To filter and separate water from the compressed air, it is usual to arrange a maintenance unit in the compressed air line (19) on the machine side in front of the solenoid valve (29).

Sheet 1 Date 18.08.89

No. 206/89-500 Or. Hu/Wa

Reference symbols

1 central lubrication pump (pneumatically operated)

2 suction strainer

3 pneumatic cylinders (pump)

4 lubricant containers

5 Pressure line (lubricant)

6 S/c-way control valve (pump)

7 relief stages: rvng with RV (pump)

8 pressure switch (lubricant), electr.

9 Fine filter (aggregate)

10 filters (central lubrication system)

11 Main line connection (central lubrication system)

12 Pressure gauge (lubricant)

13 Lubricant-air distributor (4 x)

14 Metering valve (lubricant)

15 Mixing zone (lubricant-compressed air)

16 Mixing line (lubricant-compressed air)

17 Throttle valve, adjustable (compressed air)

18 Lubrication point connection

19 Compressed air line

20 3/2-way solenoid valve (compressed air/pump)

21 Reducing valve (compressed air)

22 Pressure gauge (compressed air)

23 pressure switch (compressed air) electr.

24 level switch (lubricant), electr.

25 Control and monitoring device, pelectronic

26 Lubricant air line, outlet (4 x)

27 Compressed air connection (pneumatic cylinder)

28 Compressed air connection (unit)

29 2/2-way solenoid valve (compressed air main valve)

30 Compressed air line

31 Central lubrication pump (hydraulic operated)

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Sheet 2 Date 18.08.89

No. 206/89-500

32 3/2-way solenoid valve (hydraulic pump)

33 Hydraulic line

34 Central lubrication pump (electrically operated)

35 Lubricant-air distributor unit

36 Pressure line connection (Snhmisrstaff)

37 Compressed air line connection

38 Aggregate assembly

39 Electric motor (pump)

40 Filter block

41 Aystsuscheif.sc:*.:: (sieve filter)

42 Hydraulic cylinder {pump)

43 Differential pressure switch, electric (lubricant)

44 Pressure connection (lubrication), differential pressure switch

45 Pressure connection 2 (lubricant), differential pressure switch

46 Delivery unit (lubricant)

47 Suction line (lubricant)

48 External mounting thread (lubricant container)

49 Pump angle (pump)

50 mounting internal thread (pump angle)

51 Hood (lubricant container)

52 Viewing slot (lubricant hood)

53 Pause time symbol (control unit)

54 Pulse time symbol (control unit)

Claims (1)

1. Unit for automatic minimum quantity lubrication according to the oil-air method for viscous lubricants, comprising a lubricant container, one or more pneumatically operated, volumetrically adjustable, metering and blocked micropumps, each with a lubricating oil-compressed air mixing zone and mixing line, as well as a common compressed air supply and regulation, an oil filter on the suction side, pneumatic pressure switch and pressure gauge, an electronic control device, characterized in that there is a central lubrication pump (1, 31, 34), one or more lubricant-air distributors (13), each consisting of a housing with an exchangeable metering valve (14) with a volumetrically fixed metering quantity for viscous and consistent lubricants with the design features of the central lubrication inlet distributors, an adjustable compressed air throttle valve (17), a mixing zone (15) and a mixing line (16) connected to it, and in the pressure line (5) of the pump (1) at least one lubricant filter (9) with a differential pressure switch (43), /O Sheet 2 Date 10. 10.89 206/89-500 a hydraulic pressure switch (8), a pressure gauge (12), and, arranged hydraulically in parallel, a main line connection (11) of a central lubrication system (interface), in the compressed air line (30) has a reducing valve (21), a pneumatic pressure switch (23) and a pressure gauge (22) and is designed as a structural unit (38). . A yyreya I &pgr; ti ü fr A &Pgr; sp F ü C fr 1, characterized in that the central lubrication pump (1, 31, 34) consists of a conveyor unit (46), a drive (3, 39, 42), an exchangeable lubricant container (4), a suction line (47) with suction strainer (2), a control valve (6), a relief line (7), a level switch (24) and a 3/2-way solenoid valve (20) and is designed as an internal structural unit (I ₁ 31, 34). 3. Unit according to claim 1 and 2, characterized in that the central lubrication pump (1, 31, 34) with a drive (3, 39, 42) has a pneumatic cylinder (3), a hydraulic cylinder (42) or an electric motor (39). 4. Unit according to claim 1, 2 and 3, characterized in that the lubricant container (4) of the central lubrication pump (1, 31, 34) has an external fastening thread (48) and the pump angle (49) has an internal fastening thread (50) and both are screwed . 5. Unit according to claim 1, characterized in that several lubricant-air distributors (13) are combined to form a structural unit (35). 6. Unit according to claim 1 and 5, characterized in that UXC OUMIUJ-CXaUUXX-I-UX U~VeX UCX. L CX &mdash; DOUCXIIIICIL· \OJ ) CXIICII ./3 · I · · I · &igr;&igr; < III Sheet 3 Date IQ. 10.89 206/89-500 Connection (36) of the compressed air line (5) and a connection (37) of the compressed air line (30). 7. Unit according to claim 1, characterized in that the lubricant filter (9) is designed as a fine filter and is arranged in front of the lubricant-air distributor assembly (35). 8. Unit according to claim 1 and 7, characterized in that the hydraulic pressure connections (44, 45) for the differential pressure switch (43) are arranged before and after the lubricant filter (9). 9. Unit according to claim ₁ 17 and 8, characterized in that a central lubrication filter (10), arranged hydraulically parallel to the lubricant filter (9) and forming a filter block (40), is located in front of the main line connection (11). 10. Unit according to claim 1, 7, 8 and 9, characterized in that the sieves of the filters (9, 10) are designed as replacement inserts (41).