Method and device for lubricating a universal joint

Abstract

A universal joint contains a first joint yoke and a second joint yoke. The first joint yoke and the second joint yoke are connected by a journal cross, ends of the journal cross being mounted in the joint yokes by bearings. In order to lubricate at least one of the bearings, at least one lubricant feed-through is provided, which is provided outside of a central bore of the journal cross.

Claims

1. A journal cross for a universal joint, the journal cross comprising: journal-cross ends; mountings assigned to said journal-cross ends; and at least one feedthrough formed in said journal cross, said at least one feedthrough for a lubricant, said at least one feedthrough being provided for a supply of the lubricant from one of said journal cross ends to precisely one of said mountings assigned to a further one of said journal-cross ends.

2. The journal cross according to claim 1, wherein: the universal joint has two center axes; and said feedthrough for the lubricant is spaced from at least one of the center axes.

3. The journal cross according to claim 2, wherein said at least one feedthrough is disposed parallel to one of the center axes.

4. The journal cross according to claim 1, wherein said feedthrough is one of at least two separate feedthroughs for the lubricant.

5. The journal cross according to claim 1, wherein said at least one feedthrough has a 90° angle bend.

6. The journal cross as claimed in claim 1, wherein said at least one feedthrough is formed in the journal cross.

7. The journal cross according to claim 1, wherein said at least one feedthrough is one of a plurality of feedthroughs having openings for the lubricant, said openings are disposed at two opposing said journal ends, and all of said mountings are capable of being lubricated by means of said feedthroughs.

8. The journal cross according to claim 7, wherein said mountings include thrust bearings and radial bearings.

9. The journal cross according to claim 1, wherein said at least one feedthrough is one of two feedthroughs each having a 90° angle bend.

10. A universal joint, comprising: a first joint yoke; a second joint yoke; and a journal cross having ends supported in said first and second joint yokes, said journal cross further having mountings assigned to said ends and at least one feedthrough formed in said journal cross, said at least one feedthrough for a lubricant, said at least one feedthrough being provided for a supply of the lubricant from one of said ends to precisely one of said mountings assigned to a further one of said ends.

11. The universal joint according to claim 10, further comprising lubricant feed lines and that on two opposing sides of the universal joint, the universal joint has two said lubricant feed lines in each instance, each of said lubricant feed lines being assigned to precisely one of said mountings.

12. The universal joint as claimed in claim 10, further comprising: inner caps; outer caps; and lubricant feed lines for the lubricant are disposed at two positions on the universal joint and are disposed at an angle of 90° with regards to each other, said lubricant feed lines being formed in said inner caps.

13. The universal joint according to claim 12, wherein: said journal cross has a journal; and a lubricant feedline of said lubricant feedlines is formed only in one of said inner caps assigned to said journal of said journal cross.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Shown are:

(2) FIG. 1: cardan shaft

(3) FIG. 2: sketch of lubricant feed lines, opposing

(4) FIG. 3: sketch of lubricant feed lines at a 90° angle

(5) FIG. 4: journal cross

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows a cardan shaft 1 having a body with a universal joint at both ends. Each of the universal joints exhibits a first joint yoke 3 and a second joint yoke 5. The first joint yoke 3 is actively connected to the second joint yoke 5 via a journal cross 9. When a rotational motion is introduced via the first joint yoke 3, a rotational motion is transmitted to the second joint yoke 5, and conversely. In this connection, the axial axis of the first joint yoke 3 may have been arranged in angular manner relative to the axial axis of the second joint yoke 5. This angle is designated as the articulation angle. When it is running at an articulation angle, the simple universal joint 7 generates a non-uniformity—that is to say, on the drive side it is driven at constant speed, rotating about the axial axis thereof, but on the output side it rotates sometimes a little faster and sometimes a little more slowly than the drive side. The non-uniformity increases with the articulation angle. The joint yoke, which in the installed state executes only a rotational motion about its axial axis, is designated as a non-articulated joint part 4 or joint yoke.

(7) In FIG. 2, feedthroughs 35 for a lubrication of bearings 12 of the universal joint 7 are shown. The universal joint 7 exhibits radial bearings 15 and thrust bearings 13. By virtue of the radial bearings 15, the journal ends 11 are supported radially in relation to the center axis of the journal cross 9. By virtue of the thrust bearings 13, the journals of the journal cross 9 are supported axially. In the exemplary embodiment shown, this thrust bearing 13 is provided terminally at the journal end 11.

(8) In the exemplary embodiment shown, the mountings of the ends of the journal cross 9 have been represented in very simplified manner and labeled by A, B, C and D. In this exemplary embodiment, a first lubricant feed line 43 and a second lubricant feed line 45 have been assigned to a journal-cross end A. By virtue of the first lubricant feed line 43, the bearings of this journal end have lubricant applied. As a result, on the one hand new lubricant can be introduced, and older lubricant can also be expressed from the bearing by the new lubricant. In this way, an exchange of lubricant is consequently also possible. The excess of lubricant emerges again at a lubricant outlet 51.

(9) The second lubricant feed line 45 is connected to mounting B via a first feedthrough 37. Via this first feedthrough 37, lubricant can be supplied to mounting B. In this exemplary embodiment, the first feedthrough 37 has been realized in angled manner, and mounting B is arranged at a 90° angle relative to mounting A. A lubrication of mountings C and D is provided in the same way. In this connection, once again a first lubricant feed line 43 is provided for the lubrication for the bearings arranged there. Mounting D is supplied with lubricant via a second feedthrough 39. In this exemplary embodiment, the feed lines for lubricant are provided at two opposing ends of the journal cross. As a result, it is possible to provide a connection to a central lubricant feed line 61 in the case of a non-articulated arrangement of the joint yoke 3. Lubricant can be supplied to each mounting A, B, C, D from this central lubricant feed line 61. Each mounting A, B, C, D has been assigned its own lubricant feed line 41. As a result, it is possible to apply lubricant appropriately to each bearing. As a result, each mounting can be supplied with lubricant in a manner matched to the actual demand. But the advantage is that in the case of a standstill of the cardan shaft the cardan shaft can be positioned purposefully in a position in which the centralized lubricating system is easily accessible. A lubrication of the bearings is provided at a standstill. The lubrication can, however, also take place in operation via a rotary feedthrough.

(10) An alternative version is shown in FIG. 3. In this version, two lubricant feed lines have been respectively assigned to two journal ends. The lubricant feed lines 41 are arranged at an angle of 90°. As a result, it is possible to lubricate all the bearings of this universal joint at a standstill of the universal joint 7, without a change-over to the other side of the universal joint and hence of the cardan shaft.

(11) In this version, the first feedthrough 37 to mounting B has been formed in rectilinear manner in the journal cross. The second feedthrough 39 to mounting D has also been realized in rectilinear manner. The first center axis 31 and the second center axis 33 of the journal cross 9 have been represented by dashed lines. The feedthroughs 35 for the lubricant are spaced from at least one of the center axes 31, 33. The feedthroughs 35, are parallel to one of the center axes 31, 33. The feedthroughs 35 are formed in the journal cross 9. The feedthroughs 35 have openings for the lubricant, the openings are disposed at two opposing journal ends, and all of said mountings are capable of being lubricated the feedthroughs 35.

(12) In FIG. 4, the structure of a journal cross with bearings is represented in detailed manner. The journal cross 9 has been realized in one piece. A central recess 47 is formed in the journal cross. The center axes 31 and 33 of the journal cross have been represented by dashed lines. This central recess 47 is sealed at the end by an inner cap 27. A closure plate 49 is arranged within the central recess in each journal ends, so that there is a gap between the inner cap 27 and the closure plate 49. A lubricant feed line 45 is formed in the inner cap 27. A lubricant feedline 43, 45 of the lubricant feedlines 41 is formed only in one of the inner caps 27 assigned to the journal of the journal cross 9. When lubricant is applied, the lubricant passes into the gap between the inner cap 27 and the closure plate 49. From there, the lubricant passes into the lubricant feedthrough 37 formed in the journal cross. In the concrete exemplary embodiment, the lubricant passes into the first feedthrough 37. The feedthrough has been realized in angled manner in accordance with FIG. 2. Via this feedthrough, the lubricant reaches the assigned mounting B. In mounting B, the lubricant is conveyed to the thrust bearing 13 via the radial bearing 15 of mounting B. By virtue of the thrust bearing, the lubricant can emerge again at the lubricant outlet 51. As a result, a partial exchange of the lubricant can also be carried out, by lubricant being introduced until such time as lubricant emerges again almost without contaminants at the lubricant outlet 51.

(13) The radial bearing 15 has been realized as a roller bearing with rolling bodies 17. The rolling bodies 17 are arranged between an inner bearing element 19 and an outer bearing element 21. The inner bearing element 19 and the outer bearing element 21 are arranged coaxially in relation to the journal. An outer cap 25 is arranged axially at the end. This outer cap 25 is secured in the recess of the joint yoke by a circlip 23. As becomes evident from this representation in particular, only a few components are needed in order to be able to lubricate two mountings from one journal end.

LIST OF REFERENCE SYMBOLS

(14) 1 cardan shaft

(15) 3 first joint yoke

(16) 4 non-articulated joint part

(17) 5 second joint yoke

(18) 6 articulated joint part

(19) 7 universal joint

(20) 9 journal cross

(21) 11 ends, journal cross

(22) 12 mounting, bearings overall

(23) 13 thrust bearing

(24) 15 radial bearing

(25) 17 rolling body

(26) 19 inner bearing element

(27) 21 outer bearing element

(28) 23 circlip

(29) 25 outer cap

(30) 27 inner cap

(31) 31 first center axis

(32) 33 second center axis

(33) 35 feedthrough for lubricant

(34) 37 first feedthrough

(35) 39 second feedthrough

(36) 41 lubricant feed line

(37) 43 first lubricant feed line

(38) 45 second lubricant feed line

(39) 47 central recess, journal cross

(40) 49 closure plate

(41) 51 lubricant outlet

(42) 61 central lubricant feed line