GB2045858A

GB2045858A - Fluid pump

Info

Publication number: GB2045858A
Application number: GB8008522A
Authority: GB
Original assignee: Joseph Voegele AG
Current assignee: Joseph Voegele AG
Priority date: 1979-03-14
Filing date: 1980-03-13
Publication date: 1980-11-05
Also published as: DD158809A5; FR2451475A1; SE8001886L; IT8020571A0; IT1129749B; GB2045858B; DE2910035A1; DE2910035C2; BR8001549A

Abstract

A fluid pump for lubricants which comprises a drive shaft (3) mounted in a stationary housing (2) and driving an axially connected eccentric control shaft (6). The control shaft has a rotatable collar (8) mounted on it which forms a "cylinder ring" and has a radially inwardly extending bore which cooperates with a piston (10) pivotally mounted on the housing by means of a pin (12) parallel to the drive shaft (3). The engagement of the piston with the bore prevents the cylinder ring from rotating with the control shaft so that rotation of the drive shaft, and therefore the control shaft causes the cylinder ring to reciprocate relative to the piston. <IMAGE>

Description

SPECIFICATION Fluid pump The invention relates to a pump particularly suitable for the delivery of lubricants.

A pump is known from German Auslegeschrift 11 03 142, with which a cylinder ring is mounted so as to revolve on a stationary control shaft comprising control ports and flow ducts or passages. On both sides of the cylinder ring, the control shaft has an eccentric, on which are mounted side plates. The spacing between the side plates is established by gudgeon pins, which are clamped between the side plates. The gudgeon pins in their turn each receive a piston, which pistons are at the same time guided in radial bores of the cylinder ring. With a rotation of the cylinder ring and of the side plates with the gudgeon pins, the pistons produce suction and compression strokes in the radial bores of the cylinder ring. In addition, pressure-equalising depressions are provided in the cylinder ring or in a bush secured fast in the cylinder ring.Such a pump has a comparatively complicated and thus costly construction. The revolving parts of the pump necessitate a drive means which is specially designed. The large masses or weights have to be balanced in a costly manner, so as to achieve a running of the pump which is as far as possible free from vibration. Due to the number of the pistons, this pump has a delivery capacity which is consider ably above the necessary delivery capacity of pumps for delivering lubricants.

The present invention seeks to provide a pump for the delivery of lubricants which has a low delivery capacity - usually, only a delivery capacity between 0.11/h and 3 1/h is necessary and is of a simple and space saving design and thus can be cheaply manufactured, has few movable parts and is thus subject to only a small amount of wear and which can be adapted without any difficulties to the actual lubrication requirements.

According to the invention there is provided a fluid pump for example for lubricants and comprising a drive shaft rotatably mounted in a stationary hous ing and axially connected to an eccentric control shaft the control shaft having a rotatable collar forming a cylinder ring mounted thereon, the cylin der ring having a radially-inwardly extending bore and being restrained against rotation with the con trol shaft by engagement of a piston in the bore, which piston is pivotally mounted on said housing by means of a pin mounted parallel to said drive shaft, whereby in operation rotation of the control shaft by means of the drive shaft causes the cylinder ring to reciprocate relative to the piston.

A pump as thus constructed can be made without any great expense. It has few movable parts, so that there is scarcely any wear. As a result, the effective life of the pump and the replacement of defective parts are favourably influenced. The individual parts of the pump can be arranged in the smallest possible space, without thereby deleteriously affecting the efficiency and functioning of the pump. The pump according to the invention is a self-aspirating pump over the viscosity range of the lubricants which are used and can without any difficulty be connected to a drive means.

Further features and advantages of the invention are hereinafter more fully explained by reference to some constructional examples which are shown in a drawing, wherein: Figure lisa sectional elevation of a pump according to the invention, Figure2 is a section through the pump as shown in Figure 1 along the line I Figure 3 is another construction of a pump as a sectional elevation along the section line lil - lil in Figure 4, Figure 3a is a section on the line II - II of Figure 3, Figure 4 is the pump according to Figure 3, as a section in the region of the distributor duct of the driving shaft, Figure 5 is a modified constructional form of a pump according to the invention, shown as an elevation in section, and Figures 6to 8 are various sections through the driving shaft shown in Figure 5.

Represented in Figures 1 and 2 of the drawing is a pump 1 for the delivery of lubricants, the said pump consisting of a housing 2 with a driving shaft 3 mounted therein. For securing the driving shaft 3 in the housing 2, the said shaft has an encircling collar 4 at one end. Extending from this end of the driving shaft 3 and into the latter is a blind hole 5, which is for example of square section, the said hole serving to accommodate a corresponding square journal or spigot of a motor shaft (not shown), the housing 2 of the pump having a screw-threaded connection with the motor, for example, in a manner known perse and not illustrated.

At its end opposite to that having the collar 4, the driving shaft 3 is connected in one piece with a control shaft 6, which is arranged eccentrically of the driving shaft 3 and projects from the housing 2.

Mounted on the control shaft 6 is a cylinder ring 8 which is secured by a ring 7 and which has a bore 9 for receiving a piston 10. In its turn, the piston 10 is fixed in a holder 11, which is fitted so as to be pivotable on to a journal or gudgeon pin 12 which is fixed in the housing 2 and projects from the latter. By the piston 10 secured on the journal 12, the cylinder ring 8 is prevented from rotating when there is a rotational movement of the driving shaft 3 and thus of the control shaft 6. It is only the depth of penetration of the piston 10 in the bore 9 of the cylinder ring 8 which is changed through the eccentricity of the control shaft 6 when the latter rotates and as a result the relative movement between piston 10 and cylinder ring 8 and necessary for a piston pump is produced.

In the region of the cylinder ring 8, two control slots or ports 13, 14 arranged offset from one another by 180 are machined in the control shaft 6, the said slots being formed according to Figure 2 and each extending over an angle of about 120 .

However, the spacing between the two control slots or ports 13, 14 has to be at least of such a size that the bore 9 in the cylinder ring 8, in the position of the control shaft 6 as shown in Figure 2, can be shut off or is closed completely by that circular intermediate region of the control shaft 6 which is not covered by the ports 13, 14. In the central region of the driving shaft 3, the latter is provided with two encircling grooves 15, 16 which are arranged slightly spaced from one another and of which the groove 15 is in communication with a lubricant inlet pipe 17 machined into the housing 2, the said pipe having a screw-threaded connection for a pipe conduit, while the groove 16 is connected to a lubricant outlet pipe which is arranged and formed in the same way but which is not shown in the drawing.

From that free end face 18 of the control shaft 6 which is adjacent the cylinder ring 8, two flow passages 19, 20 extend axially and in spaced relation parallel to one another lead through the control shaft 6 to the region of the grooves 15, 16 of the driving shaft 3, which grooves are sealed off at the end face 18 of the control shaft 6 by a plug 21 which is advantageously screwed in position. The flow passage 19 communicates bywayofan opening 22 with the control port 13 and by way of a bore 23 with the groove 15, while an opening 24 leads from the flow passage 20 to the control port 14 and a bore 25 leads to the groove 16.

The time of switching on the pump 1 and with the initiation of the rotational movement of the driving shaft 3 and of the control shaft 6 which takes place in a counter-clockwise direction according to the arrangement which is shown in Figure 2, the cylinder ring 8 is moved away over a curved path by the journal 12 and thus by the piston 10, due to the eccentricity of the control shaft 6. As a result, a reduced pressure is established in the bore 9 and this pressure, when the control port 13 comes into the region of the bore 9, has the effect of drawing in lubricant through the lubricant inlet or admission pipe 17, the groove 15, the bore 23, the flow passage 19, the opening 22 and the control port 13, so that the bore 9 in the cylinder ring 8 is filled with lubricant.As soon as the control shaft 6 has reached a position turned through 1800 as compared with Figure 2, the piston 10 assumes its maximum spacing from the control shaft 6, the suction stroke is terminated and the bore 9 is closed again by a circular intermediate region of the control shaft 6 which is not covered by the control ports 13, 14.

With the further rotation of the driving shaft 3 and of the control shaft 6, firstly the control port 14 comes into the region of the bore 9, while secondly the distance between the control shaft 6 and the piston 10 is reduced. As a result, the lubricant contained in the bore 9 is forced through the control port 14, the opening 24, the flow passage 20, the bore 25 and the groove 16 into the lubricant outlet pipe (not shown). As soon as the control shaft 6 has once again reached its starting position which is shown in Figure 2, the compression or delivery stroke is terminated and the bore 9 is closed again.

The operations as previously described are repeated with every complete rotation of the driving shaft 3 and control shaft 6. If the pump 1 is fitted into a single-conduit lubrication plant, the lubricant is delivered to measuring or proportioning valves, which are arranged before the lubrication points. As soon as it is ensured, for example, by supervising the pump pressure, that all measuring valves have delivered to the lubrication point a quantity of lubricant corresponding to its measured volume, the pump is once again switched off.

As an addition to this constructional example, it is possible to machine pressure-balancing troughs as known perse into the control shaft 6 or into the cylinder ring 8. If required, the driving shaft 3 can be extended on the free end face of the control shaft 6, so that the said driving shaft can be mounted on both sides of the control shaft 6. However, as is the case with the pressure-balancing troughs, this is normally only necessary with relatively large delivery pressures. Furthermore, it is possible to make the control shaft 6 so long that two or more cylinder rings can be arranged thereon, with which rings always only one particular piston is associated. It is possible in this way for two or more lubricating pipe systems which are separate from one another to be supplied with lubricant.However, this may in like manner also be effected by two or more driving shafts which are arranged parallel to one another in one housing and which have control shafts, cylinder rings, pistons and separate lubricant outlet pipes.

With a common lubricant outlet pipe, an almost continuous flow of lubricant can be obtained by suitable superimposition of the individual delivery strokes.

Represented in Figures 3 and 4 of the drawing is a modified pump 1 a, with which the lubricant is distributed to four lubricant outlet pipes. Those parts of the pump 1 a which correspond as regards their function to the parts of the pump 1 are given the same reference numerals, but additionally bear the letter "a".

The pump 1 a likewise consists of a housing 2a with a driving shaft 3a, which has at its free end milled surfaces 5a for the positive connection to a driving motor and is secured by a ring 4a in the housing 2a. At the other end of the driving shaft 3a, a control shaft 6a is fixed eccentrically of said shaft 3a, the said shaft 6a likewise receiving a cylinder ring 8a which is secured by a ring 7a. Engaging in the bore 9a of the cylinder ring 8a is a piston 10a, which is held by a holding means 1 1a and a journal 1 2a so as to be pivotable on the housing 2a and locks the cylinder ring 8a against a turning movement on the control shaft 6a. Connected to the free end of the control shaft 6a is an extension 26, on which a disc or plate 27 is fixed as a counter-balance. With this extension 26, the pump 1a is so introduced into a lubricant storage containerthatthe extension is disposed in the lubricant. According to Figure 3a, the extension 26 has a recess 28, with which the lubricant is "worked" and which facilitates the aspiration.

In the region of the cylinder ring 8a, the control shaft 6a also has two control slots or ports 13a, 14a, of which only the control port 13a is to be seen in Figure 3. From this control port 13a, an opening 22a leads to a flow passage 19a, which opens out in the region of the recess 28 and through which the lubricant is aspirated. From the rear control port 14a, which cannot be seen, an opening 24a leads to an axial flow passage 20a, which opens on to the free end of the driving shaft 3a and is closed off here by a plug 21a. In the middle region of the housing 2a, the driving shaft 3a has machined therein a distributor duct 29 which extends transversely through the said shaft and the flow passage 20a (Figure 4).

By contrast with the pump 1, the driving shaft 3a of the pump la is not mounted directly in the housing 2a, but in a separate control bush 30, which is fitted fast against rotation into the housing 2a. This control bush 30 comprises several (four in this constructional example) distributor ports 31 to which lubricant can be admitted in succession with one rotation of the driving shaft 3a, each of said ports having associated therewith a lubricant outlet pipe 32 having means by which it is possible for a pipe conduit or hose to be screwed thereon. In this constructional example, each distributor port 31 has associated therewith, directly opposite, an additional port or slot 43, which makes possible a pressure balancing and thus a symmetrical loading of the driving shaft 3a and housing 2a.

The distributor ports 31 may be made with the same or unequal size or length and they are arranged either evenly or irregularly over the circumference of the control bush 30. What is established by their length is the angle of rotation over which they communicate with the distributor duct 29 during the compression or delivery stroke of the pump la. Their arrangement in the control bush 30 establishes in which zone of the sine curve of the compression or delivery stroke the connection is made. The length and the arrangement of the distributor ports 31 thus determines the amount of lubricant which is supplied to the separate lubricant outlets during the compression or delivery stroke of the pump 1 a, i.e. the distribution of the lubricant quantity of one compression or delivery stroke.This distribution is also prescribed by the control bush 30 and can be changed by replacing the latter. Any change in the distribution of the lubricant is impossible while the pump is operating.

Illustrated in Figure 5 of the drawing is a construction of a pump 1 b, with which the quantity of lubricant to be supplied with one compression or delivery stroke of the pump 1 b can be modified or measured. Those parts which correspond in their function to the parts of the pumps 1 and 1 a have the same reference numerals, but with the addition of the letter "b". The pump 1 b likewise has a housing 2b with a driving shaft 3b secured by a ring 4b. The driving shaft 3b is connected to an eccentric control shaft 6b, on which is mounted a cylinder ring 8b secured by a ring 7b. A piston 10b pivotally mounted on the housing 2b is also guided in this cylinder ring 8b, which piston prevents rotational movement of the cylinder ring 8b on the control shaft 6b.Fixed to the free end of the control shaft 6b is a suction pipe 26b, which projects perpendicularly into a lubricant container. This suction or aspirating pipe 26b is in alignment with the driving shaft 3b.

In this case also, the cylinder ring 8b has two diametrically opposite control ports 1 3b, 1 4b, of which only the port 14b is to be seen in Figure 5.

From the port 1 3b which is at the rear in the drawing, an opening 22b leads to a flow passage 19b, which passes into the aspirating pipe 26b. This flow passage 1 9b extends into the driving shaft 3b and in fact extends until it is in the region of two control grooves 33, 34, which are milled at a distance from one another into the surface of the driving shaft 3b. It can be seen from Figures 6 and 8 that these control grooves 33,34 only extend over a part of the circumference of the driving shaft 3b, are of unequal length and occupy an unequal angular position relatively to one another. The control grooves 33,34 are connected through bores 33, 36 to the flow passage 19b.

Machined in the driving shaft 3b between the control grooves 33,34 is another encircling groove 16b, which is connected by way of a bore 25b, an axial flow passage 20b and an opening 24b to the control port 14b. Opening into the encircling groove 16b of the driving shaft are a lubricant outlet pipe 32b with a non-return valve 37 and a possible means of connection for a pipe conduit or hose, and also a passage 37, which is arranged diametrically opposite the lubricant outlet pipe 32b in Figures 5 and 7.

The passage 37 joins a bore 38 which extends parallel to the driving shaft 3b and from which, in turn, a passage 39,40 leads respectively to one of the control grooves 33 and 34 of the driving shaft 3b.

Associated in this case with each passage 39,40 is a locking element 41,42 which can be screwed in and by which, as shown in respect of the locking element 41, the flow connection from the bore 38 to the passage 39 and thus to the control groove 33 can be closed off.

The lubricant conveyed with the compression or delivery stroke of the pump 1 b through the flow passage 20b to the groove 16b is here distributed to the lubricant outlet pipe 32b and the passage 37 with bore 38 and passages 39,40. From the passages 39, 40, the lubricant flows through the control grooves 33,34 into the flow passage 19b and thus back through the pipe 26b into the lubricant container. If both locking elements 41,42 are closed, ail the lubricant of a compression or delivery stroke flows into the lubricant outlet pipe 32b. If, for example, only the locking element 41 is closed, as illustrated, the lubricant of the compression or delivery stroke is distributed to the lubricant outlet pipe 32b and to the passage 40.In this case, as can be seen from Figure 8, the passage 40 is then only able to deliver lubricant to the control groove 34 for the return flow when the said passage has a flow connection with the control groove 34 and is not closed by the groove-free part of the driving shaft 3b. This means that the proportion of the lubricant quantity of one delivery stroke which is able to flow back into the lubricant container is prescribed by the length and the arrangement of the control grooves 33,34. As a consequence, that quantity of lubricant which flows into the lubricant outlet pipe with a delivery stroke is infinitely adjustable by means of the locking elements 41, 42.

In a modified form of the constructional examples of Figures 3 and 5, it is also possible in this case to machine pressure-balancing troughs into the control shaft 6a and 6b, respectively, in the vicinity of the cylinder ring 8a or 8b. Furthermore, it is possible in all constructional examples to arrange the lubricant inlet pipe and/or lubricant outlet pipe or pipes directly on the cylinder ring, in which case the said ring has to comprise the necessary passages and bores.

Claims

1. Afluid pump for example for lubricants and comprising a drive shaft rotatably mounted in a stationary housing and axially connected to an eccentric control shaft, the control shaft having a rotatable collar forming a cylinder ring mounted thereon, the cylinder ring having a radially inwardly extending bore and being restrained against rotation with the control shaft by engagement of a piston in the bore, which piston is pivotally mounted on said housing by means of a pin mounted parallel to said drive shaft, whereby in operation rotation of the control shaft by means of the drive shaft causes the cylinder ring to receiprocate relative to the piston.

2. A pump according to claim 1, characterised in that the control shaft has arranged thereon two or more cylinder rings each of which cooperates with a respective piston pivotally mounted on the housing.

3. A pump according to claim 1, characterised in that the housing has arranged therein two or more drive and control shafts each having one cylinder ring and one piston and the drive shafts are connected to a common drive means.

4. A pump according to any one of claims 1 to 3 in which fluid is conveyed via control ports and ducts in said shafts and in that the housing comprises at least two lubricant outlets and a positive and/or non-positive control bush surrounding said drive shaft and has at least two distributor ports fitted into the housing.

5. A pump according to claim 4, characterised in that the distributor ports are made equal or unequal in size and are distributed symmetrically or unsymmetrically over the periphery of the control bush.

6. A pump according to claim 4 or claim 5, characterised in that the distributor ports are arranged symmetrically and at least one symmetrical bore or recess of the drive shaft is associated therewith.

7. A pump according to claim 1, characterised in that the lubricant outlet pipe has connected them to a passage which is in communication by way of shut-off valves with control grooves of the drive shaft, which grooves in their turn are connected to form a short-circuiting duct to the lubricant inlet pipe.

8. A pump according to claim 7, characterised in that the shut-off valves are constructed as throttle valves with conical seats.

9. A pump according to claim 7, characterised in that the control grooves of the drive shaft are of different lengths and are arranged offset from one another.

10. A pump according to any of claims 1 to 9, characterised in that the flow ducts or passages serving for the delivery of lubricant are connected by or through the control shaft directly or by or through the driving shaft to the lubricant inlet pipe and lubricant outlet pipe, respectively.

11. A pump according to any one of claims 1 to 10, characterised in that a pipe serving for the lubricant supply is arranged on the control shaft.

12. A pump according to claim 11,characterised in that the pipe is fixed concentrically with or eccentrically of the driving shaft on the control shaft.

13. A pump according to claim 11 or claim 12, characterised in that the pipe is equipped with special working or recovery elements for the lubricants.

14. A pump according to any of claims 1 to 13, characterised in that the lubricant inlet and lubricant outlet pipe or pipes open on the cylinder ring.

15. A pump according to claim 1, characterised in that the control shaft is provided with a counterbalance means.

16. A pump according to claim 1, characterised in that the cylinder ring and/or control shaft is provided with pressure-relieving grooves or ports.

17. A pump according to any one of claims 1 to 16, characterised in that the drive shaft is mounted overhung or at both ends.

18. A fluid pump substantially as herein described with reference to Figures 1 and 2 or Figures 3 and 4 or Figures 5 to 8 of the accompanying drawings.