Lubricating device

Abstract

The present invention relates to a lubrication device (1) comprising a pump unit (3) with a cylinder (6), a plurality of lubricant lines (7) fluidically connected to the cylinder (6), and a piston (8) rotatably and axially displaceably mounted in the cylinder (6), wherein the pump unit (3) is designed such that one of the lubricant lines (7) can be selected by means of a piston rotation movement and a lubricant volume defined by the piston stroke (H) can be drawn in and delivered to a selected lubricant line (7) by means of a piston axial movement, wherein the piston stroke (H) of the delivery movement of the piston (8) can be subdivided into different numbers of equal partial piston strokes (h) for metering purposes, and wherein a control (4) is provided which is configured such that the number of equal partial piston strokes (h) can be set uniformly for all lubricant lines (7).wherein the control (4) is arranged such that the number of equal partial piston strokes (h) can be set non-uniformly for at least some lubricant lines (7).

Description

[0001] The present invention relates to a lubrication device comprising a pump unit with a cylinder, a plurality of lubricant lines fluidically connected to the cylinder, and a piston rotatably and axially displaceably mounted in the cylinder, wherein the pump unit is designed such that one of the lubricant lines can be selected by means of a piston rotation movement and a lubricant volume defined by the piston stroke can be drawn in and delivered to a selected lubricant line by means of a piston axial movement, wherein the piston stroke of the delivery movement of the piston can be subdivided into different numbers of equal partial piston strokes, and wherein a control is provided which is set up such that the number of equal partial piston strokes, i.e., partial piston strokes with equal stroke volumes, can be set uniformly for all lubricant lines.Furthermore, the invention relates to the use of such a lubrication device for supplying several lubrication points of a knitting machine with lubricant, a method for supplying several lubrication points of a machine, in particular a knitting machine, using such a lubrication device, a computer program and a computer-readable medium.

[0002] The needle drive, as well as the needle guides in the needle bed or needle cylinder of knitting machines, require constant lubrication with a lubricant. Proper lubrication is particularly important for modern, high-speed knitting machines. Insufficient lubricant supply leads to increased wear and may even cause the knitting machine to fail. Excessive lubricant supply can damage the knitted fabric due to dripping lubricant. Therefore, it is essential to ensure the correct dosage of oil supplied to each lubrication point on the knitting machine.

[0003] Known lubrication devices operate either with compressed air or with a piston pump. The present invention relates to lubrication devices of the latter type. One such device is disclosed, for example, in EP 1 026 300 A1. This device comprises a pump unit with a cylinder, a plurality of lubricant lines fluidly connected to the cylinder, and a piston rotatably and axially displaceably mounted in the cylinder. The pump unit is designed such that one of the lubricant lines can be selected by means of a rotary piston movement, and a volume of lubricant defined by the piston stroke can be drawn in and delivered to the selected lubricant line by means of an axial piston movement. The piston stroke of the delivery movement can be divided into different numbers of partial piston strokes for metering purposes.The lubrication system is controlled in such a way that the number of partial piston strokes can be set uniformly for all lubrication lines. If, for example, the piston stroke of the conveying movement can be divided into a maximum of 12 equal strokes, then the piston stroke can be divided into two, three, four, six, or twelve equal partial piston strokes. Accordingly, during a complete piston stroke, lubricant is then conveyed to the selected lubrication point of the machine with individual pulses generated by the partial piston strokes. The size of the partial piston strokes must be adjusted so that a sufficient volume of lubricant at sufficient pressure is available at the end of each lubrication line to ensure that the lubricant is expelled in a controlled spray pattern through a nozzle located there, thus preventing lubricant from dripping.

[0004] Based on this prior art, it is an object of the present invention to provide a lubrication device of the type mentioned above with an alternative design. Furthermore, it is an object of the invention to provide a corresponding method for supplying lubrication to several points of a machine, in particular a knitting machine, a corresponding computer program, and a corresponding computer-readable medium.

[0005] To solve this problem, the present invention provides a lubrication device comprising a pump unit with a cylinder, a plurality of lubricant lines fluidically connected to the cylinder, and a piston rotatably and axially displaceably mounted in the cylinder, wherein the pump unit is designed such that one of the lubricant lines can be selected by means of a piston rotation movement and a lubricant volume defined by the piston stroke can be drawn in and delivered to a selected lubricant line by means of a piston axial movement, wherein the piston stroke of the delivery movement of the piston can be subdivided into different numbers of equal partial piston strokes, i.e., partial piston strokes with equal stroke volumes, and wherein a control is provided which is configured such that the number of equal partial piston strokes can be set uniformly for all lubricant lines, characterized in thatthat the control system is set up in such a way that the number of identical partial piston strokes can be set non-uniformly for at least some lubricant lines.

[0006] The ability to adjust the number of partial piston strokes for at least some lubricant lines in a non-uniform manner significantly increases the flexibility of the lubrication system according to the invention compared to conventional lubrication systems. In particular, lubricant lines of varying lengths can be selected while maintaining optimal lubricant supply, which simplifies both the positioning of the pump unit and the routing of the normally very rigid lubricant lines. Piston strokes that supply longer lubricant lines are simply divided into fewer partial piston strokes than other piston strokes that supply shorter lubricant lines.Accordingly, it can be easily ensured that a sufficient volume of lubricant with sufficient pressure is provided at the free end of each lubricant line to expel the lubricant in a defined spraying manner, especially by using a suitable outlet nozzle.

[0007] Preferably, at least six lubricant lines are fluidically connected to the cylinder, and in particular at least twelve lubricant lines, in order to be able to supply as many lubrication points of a machine as possible with lubricant using a single lubrication device according to the invention.

[0008] It is advantageous to provide lubricant lines of different lengths, for example, lubricant lines with a length of 4m and those with a length of 5m. This allows easy access to lubrication points on machines that are located further away from the actual pump unit.

[0009] The piston stroke of the conveying movement of the piston is preferably divisible into a maximum of twelve equal minimum partial piston strokes, in particular into a maximum of twenty-four equal minimum partial piston strokes, which enables a very good and fine adjustment of the pressure at the outlet nozzles.

[0010] According to one embodiment of the present invention, the control system is configured such that the number of equal partial piston strokes for at least some lubricant lines is automatically adjusted during operation, in particular depending on a measured ambient temperature and / or a temperature measured on or in the area of ​​at least one machine component of a machine to be supplied with lubricant and / or a measured lubricant temperature. This ensures proper lubrication of the respective lubrication points even under changing ambient conditions.

[0011] Furthermore, the present invention proposes to use a lubrication device according to the invention for supplying lubricant to several lubrication points of a knitting machine, in particular a circular knitting machine.

[0012] To solve the aforementioned problem, the present invention also provides a method for supplying several lubrication points of a machine, in particular a knitting machine, with lubricant using a lubrication device according to the invention, the lubricant lines of which lead to different lubrication points of the knitting machine, wherein the method has an adjustment step in which the number of partial piston strokes by which lubricant is conveyed to a first lubricant line is set higher than the number of partial piston strokes by which lubricant is conveyed to a second lubricant line, wherein the length of the first lubricant line is in particular shorter than the length of the second lubricant line.

[0013] Preferably, the number of equal partial piston strokes (h) set in the setting step for different lubricant lines is automatically adjusted for at least some lubricant lines during operation, in particular depending on a measured ambient temperature and / or a temperature measured on or in the area of ​​at least one machine component and / or a measured lubricant temperature.

[0014] Furthermore, a computer program for controlling a lubrication device according to the invention is provided, comprising program code means which, when the computer program is executed on the control, cause the control to enable the execution of the setting step of the method according to the invention.

[0015] Finally, the present invention provides a computer-readable medium comprising instructions which, when executed on the control of a lubrication device according to the invention, cause the control to enable the execution of the adjustment step of the method according to the invention.

[0016] Further features and advantages of the present invention will become clear from the following description with reference to the accompanying drawing. Therein is Figure 1 is a schematic view of a lubrication device according to an embodiment of the present invention; Figure 2 is a schematic cross-sectional view of a pump unit of the Figure 1 lubrication device shown; Figure 3 a cross-sectional view along line III-III in Figure 2 without a connected lubricant line; and Figure 4, an enlarged schematic cross-sectional view of a partial area of ​​the in Figure 2 shown pump unit.

[0017] The figures show a lubrication device 1 according to an embodiment of the present invention or components thereof. The lubrication device 1 comprises a lubricant reservoir 2 filled with lubricant and a pump unit 3 attached to it, the lower free end of which is immersed in the lubricant and which is controlled by a control unit 4.The pump unit 3 comprises, as will be explained in detail below, a housing 5, a cylinder 6 arranged in the housing 5, a plurality of lubricant lines 7 which are fluidically connected to the cylinder 6 and led out of the housing 5, and a piston 8 rotatably and axially displaceably mounted in the cylinder 6, wherein the pump unit 3 is designed such that one of the lubricant lines 7 can be selected by means of a piston rotation movement and a lubricant volume defined by the piston stroke can be drawn in and conveyed to a selected lubricant line 7 by means of a piston axial movement.

[0018] The cylinder 6 is designed in the form of a through-bore provided in a cylinder body 9 and is equipped in its lower region with a check valve 10, which allows lubricant to be drawn into the cylinder 6 but prevents lubricant from escaping from the cylinder 6. Above the check valve 10, the cylinder body 9 is equipped with a bore, as is particularly evident in Figure 3 As shown, twelve radial bores 11, extending in a common horizontal plane and arranged essentially uniformly, are provided. Check valves (not shown in detail) are inserted into these bores, and lubricant lines 7 are connected to each of them on the outside. The check valves prevent lubricant from flowing back from the lubricant lines 7 into the cylinder 6.

[0019] The piston 8 is rotatably and axially displaceably mounted within the cylinder 6 between bottom dead center and top dead center. It is provided with a control groove 12, which extends upwards from its lower end face 13 parallel to the piston axis across the cylindrical surface of the piston 8. The length of the control groove 12 is selected such that, depending on the rotational position of the piston 8, it establishes a fluid connection between the cylinder volume and one of the lubricant lines 7, regardless of the axial position of the piston 8 between bottom dead center and top dead center. The width of the control groove 12 corresponds essentially to the diameter of the radial bores 11. The depth of the control groove 12 is selected such that the flow resistance in the control groove 12 is not significantly greater than the flow resistance in the respective radial bores 11 or lubricant lines 7.The piston 8 is connected to an actuating rod 14, which can be driven either rotationally between defined rotary positions or axially via a drive 15, designed here as a stepper motor, and a mechanism not described in detail here but known in principle from EP 1 026 300 A1. A total of thirteen rotary positions are provided. In twelve of these rotary positions, the control groove 12 is in fluid communication with one of the radial bores 11. In the thirteenth rotary position, which is in . Figure 3 As shown and defining a rest position, the control groove 12 is not fluidically connected to any of the radial bores 11. In the axial direction, the piston 8 is movable within the cylinder 6 between the dead centers, the distance between the dead centers defining the piston stroke H. The piston stroke H of the conveying movement of the piston 8 from top dead center to bottom dead center is, as shown in Figure 4As schematically indicated, the piston stroke can be subdivided into a maximum of twenty-four minimum partial piston strokes hmin, which can be realized via the drive 15. If, for example, the piston stroke H has a volume of 100 mm³, then the twenty-four minimum partial piston strokes hmin each have a volume of approximately 4.2 mm³. The number of equal partial piston strokes h, i.e., partial piston strokes with equal stroke volumes, in which the piston 8 is moved stepwise from top dead center to bottom dead center, can be set via the control 4. The volume of a partial piston stroke h always corresponds to an integer multiple of the minimum partial piston stroke hmin.For example, the piston stroke H can be divided into twenty-fourths with twenty-four partial piston strokes h à 4.2 mm³, into twelveths with twelve partial piston strokes h à 8.4 mm³, into sixths with six partial piston strokes h à 16.7 mm³, into quarters with four partial piston strokes h à 25.0 mm³, into thirds with three partial piston strokes h à 33.3 mm³, or into halves with two partial piston strokes h à 50.0 mm³, the aforementioned values ​​being rounded. It is also possible to set a single piston stroke H, so that it is not subdivided.In this way, the delivery pressure prevailing at the end of each individual lubricant line 7 and the lubricant volume delivered per partial piston stroke h can be influenced, thus enabling adaptation to different lubricant line lengths and / or different lubricant line materials and / or different lubricant viscosities and / or different temperatures prevailing at the end of the lubricant lines 7, in order to ensure that the lubricant is dispensed without dripping at the lubrication points of a machine, in particular a knitting machine. The control 4 is configured such that the previously described setting of the number of partial piston strokes h can be made non-uniform for at least some rotational positions of the piston 8 and thus for at least some of the lubricant lines 7. In particular, the number of partial piston strokes h can be set separately for each lubricant line 7.The control unit 4 is also set up in such a way that the number of equal partial piston strokes h, which have been set in the control unit 4 for different lubricant lines 7, is automatically adjusted for at least some lubricant lines 7 during operation depending on a measured ambient temperature and a measured temperature at the lubrication point to which the corresponding lubricant line 7 leads.

[0020] At the free lower end of the housing 5, which is immersed in the lubricant contained in the lubricant reservoir 2 during operation, a pot-shaped micro-sieve 16 is provided to prevent the ingress of particles contained in the lubricant when lubricant is drawn in.

[0021] To commission the lubrication system 1, the lubricant reservoir 2 with the attached pump unit 3 is positioned on a machine, in this case a circular knitting machine. The lubricant lines 7 are then laid along the machine to the desired lubrication points. Since the routing distances of the lubricant lines 7 to the respective lubrication points vary in length, lubricant lines 7 of different lengths are used, for example, 4 m and 5 m long. It should be noted that other lengths can, of course, be selected. In this case, a temperature sensor is also positioned in the vicinity of at least one lubrication point, which transmits its measurement data to the control unit 4. Furthermore, an ambient temperature sensor is provided, which also transmits its measurement data to the control unit 4.In a further step, the number of partial piston strokes h for each lubricant line 7 is set at the control unit 4. Specifically, a smaller number of partial piston strokes h is selected for longer lubricant lines 7 than for shorter lubricant lines 7 to compensate for the higher friction losses associated with the longer lubricant lines 7. Other or alternative influencing factors that can be considered when setting the number of partial piston strokes h for a lubricant line include the material(s) of the lubricant lines, the viscosity of the lubricant, the temperatures prevailing at the free ends of the lubricant lines, and the like.

[0022] To put the lubrication device 1 into operation, it may also be necessary to first vent the pump unit 3. For this purpose, the piston 8 is rotated into a venting position in which its control groove 12 aligns with a radial bore 11 that is open to the outside environment. One or more complete piston strokes H then expel the air and fill the pump volume with lubricant. Normal operation can then commence.

[0023] During normal operation, the piston 8 is moved from bottom dead center by the piston stroke H to top dead center, drawing in lubricant and filling the cylinder 6. The piston 8 is then rotated such that the control groove 12 is fluidically connected to a desired lubricant line 7, into which the drawn-in lubricant volume is to be delivered. The piston 8 is then moved stepwise towards bottom dead center in equal partial piston strokes h, pre-set for this lubricant line 8. With each partial piston stroke h, a corresponding volume of lubricant at a predetermined pressure is delivered through the lubricant line to the lubrication point of the machine and, in particular, sprayed in pulses via a discharge nozzle.During the brief pauses between the individual partial piston strokes h, the pressure drops below a limit pressure required to overcome the outlet nozzle. By appropriately adjusting the number of partial piston strokes h into which the piston stroke H for the corresponding lubricant line 7 is divided, proper lubricant discharge at the lubrication point is ensured. In particular, lubricant dripping from the outlet nozzle is prevented.

[0024] During operation, the number of equal partial piston strokes h, which were set in the setting step for different lubricant lines 7, can optionally be automatically adjusted during operation for those lubricant lines 7 at whose lubrication points temperature sensors are positioned, depending on the temperatures measured by these temperature sensors. Likewise, automatic adjustment can be made depending on the measured ambient temperature and / or a measured lubricant temperature and / or a temperature measured on or in the area of ​​a machine component. This ensures that optimal lubrication is guaranteed even under changing ambient conditions.

[0025] The adjustment step, in which the number of partial piston strokes for the individual lubricant lines is set, as well as the automatic adjustment, is implemented in the control system by means of program code, which, when the computer program is executed on the control system, cause the control system to enable the execution of the adjustment step.

[0026] It should be clear that the embodiment described above serves only as an example and is not to be understood as limiting. Rather, modifications and changes are possible without departing from the scope of protection defined by the accompanying claims. In particular, all features that are optional in the claims are also optional in the described embodiment. Reference symbol list

[0027] 1 Lubrication device 2 Lubricant reservoir 3 Pump unit 4 Control unit 5 Housing 6 Cylinder 7 Lubricant line 8 Piston 9 Cylinder body 10 Check valve 11 Radial bores 12 Control groove 13 End face 14 Actuating rod 15 Actuator 16 Microfilter Piston stroke h min Partial piston strokes

Claims

1. Lubrication device (1) comprising a pump unit (3) with a cylinder (6), a plurality of lubricant lines (7) fluidically connected to the cylinder (6), and a piston (8) rotatably and axially displaceably mounted in the cylinder (6), wherein the pump unit (3) is designed such that one of the lubricant lines (7) can be selected by means of a rotary piston movement, and a lubricant volume defined by the piston stroke (H) can be drawn in and delivered to a selected lubricant line (7) by means of an axial piston movement, wherein the piston stroke (H) of the delivery movement of the piston (8) can be subdivided into different numbers of equal partial piston strokes (h) for metering purposes, and wherein a control (4) is provided which is configured such that the number of equal partial piston strokes (h) can be set uniformly for all lubricant lines (7), characterized by the fact thatthe control (4) is set up in such a way that the number of equal partial piston strokes (h) can be set non-uniformly for at least some lubricant lines (7).

2. Lubrication device (1) according to claim 1, characterized by the fact that at least six lubricant lines (7) are fluidically connected to the cylinder (6), in particular at least twelve lubricant lines (7), or even better at least twenty-four lubricant lines (7).

3. Lubrication device (1) according to claim 1 or 2, characterized by the fact that Lubricant lines (7) of different lengths are provided.

4. Lubrication device (1) according to one of the preceding claims, characterized by the fact that the piston stroke (H) of the conveying movement of the piston (8) into a maximum of twelve equal minimum partial piston strokes (h) min ) is divisible, in particular into a maximum of twenty-four equal minimum partial piston strokes (h min ).

5. Lubrication device (1) according to one of the preceding claims, characterized by the fact that the control (4) is set up such that the number of equal partial piston strokes (h) for at least some lubricant lines (7) is automatically adjusted during operation, in particular depending on a measured ambient temperature and / or on a temperature measured on or in the area of ​​at least one machine component of a machine to be supplied with lubricant and / or on a measured lubricant temperature.

6. Use of a lubrication device (1) according to one of the preceding claims for supplying lubricant to several lubrication points of a knitting machine.

7. Method for supplying several lubrication points of a machine, in particular a knitting machine, with lubricant using a lubrication device (1) according to one of claims 1 to 5, the lubricant lines of which lead to different lubrication points of the knitting machine, wherein the method has an adjustment step in which the number of equal partial piston strokes (h) by which lubricant is conveyed to a first lubricant line (7) is set higher than the number of equal partial piston strokes (h) by which lubricant is conveyed to a second lubricant line (7), wherein the length of the first lubricant line (7) is in particular shorter than the length of the second lubricant line (7).

8. Method according to claim 7, characterized by the fact thatthe control (4) is set up such that the number of equal partial piston strokes (h) set in the setting step for different lubricant lines (7) is automatically adjusted for at least some lubricant lines (7) during operation, in particular depending on a measured ambient temperature and / or a temperature measured on or in the area of ​​at least one machine component and / or a measured lubricant temperature.

9. Computer program for a control of a lubrication device (1) according to one of claims 1 to 5, comprising program code means which, when the computer program is executed on the control (4), cause the control (4) to enable the execution of the setting step of the method according to claim 7.

10. Computer-readable medium comprising instructions which, when executed on the control (4) of a lubrication device (1) according to any one of claims 1 to 5, cause the control (4) to enable the execution of the setting step of the method according to claim 7.

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