DE9311059U1 - Linear guide unit with integrated lubrication system - Google Patents

Description

The invention relates to a linear guide unit comprising a rail with an axis and a bearing main body which is guided in the axial direction of this rail by closed rolling element circuits, whereby load-bearing rolling element rows of two rolling element circuits are adjacent to one another and on the one hand rest against a load-bearing raceway of the rail and on the other hand against a load-bearing raceway of the bearing main body, whereby a lubricant channel system is provided within the bearing main body for supplying the load-bearing rolling element rows, of which at least one discharge opening is located in the region of the axial longitudinal extension of the load-bearing rolling element rows.

In a linear guide unit known from DE-OS 35 27 886, the rolling element balls are guided or arranged in four ball circuits. Each ball circuit has a load-transferring row of balls, which are arranged between a load-transferring track of the main bearing body and a load-transferring track of the rail. Two semicircular curved guides are connected to the load-transferring row of balls, in which the unloaded balls are deflected by 180° and fed to an unloaded ball return row. The two curved guide channels are arranged in end plates attached to the main bearing body, while the guide channel for the ball return row consists of an axially parallel bore arranged in the main bearing body. When moving the guide carriage or the bearing main body, the balls in each of the four ball circuits move along an oval path, with one ball leaving the loaded ball row and entering one of the two curved guides arranged in an end plate.

occurs, while at the other end of the loaded row of balls a ball from the other curved guide moves up.

In the rolling bearing according to DE-OS 35 27 886, an integrated lubricant channel system is proposed, which consists of channels arranged in the end plates, by means of which a lubricant can be guided to the balls located in the curved guide grooves. This arrangement offers the advantage that the lubricant guide channels can be easily manufactured in the end plates, which are usually made of plastic. In addition, the end plates allow a symmetrical arrangement of the lubricant supply connection, so that the lubricant can be evenly distributed.

It has been found to be a disadvantage of this arrangement that the lubricant is supplied in an area of the respective ball circuit in which the balls are not loaded. In particular with guide carriages or linear roller bearings that only have to cover short strokes or distances, as is the case with some machine tools that carry out periodic movements, it can happen that individual balls always remain in the load-transferring ball row and never complete a complete ball circuit.

This means that the lubrication of these load-transferring balls is inadequate or has to be achieved by using a very high _amount of lubricant. It is therefore desirable, particularly in the case of linear guide units used in short-stroke designs, to supply the lubricant directly to the loaded row of rolling elements or balls.

Linear guide units have also become known in which a lubrication hole is arranged in the main bearing body, which opens into the gap formed on the inside of the main bearing body between the rail and the main bearing body. Such a hole makes it possible to supply the lubricant directly to the load-transferring rows of balls, but problems arise in that in a linear guide unit with two rows of rolling elements arranged one above the other, the lower row of rolling elements is only inadequately supplied. In addition, such an arrangement of a lubrication hole in the main bearing body is unfavorable, since the lubricant is not only supplied to the rows of balls, but is distributed in the gap between the main bearing body and the rail, thus resulting in high lubricant consumption and possibly high environmental pollution.

The invention is therefore based on the object of designing a generic linear guide unit in such a way that the lubricant channel system conveys the lubricant directly to the load-bearing rows of balls or rolling elements, whereby the adjacent load-bearing rows of rolling elements are to be evenly lubricated and the lubricant consumption is to be minimized.

The solution to the problem is characterized in a generic linear guide unit according to the invention in that at least one lubricant channel of the lubricant channel system opens into an area between the two adjacent load-bearing rows of rolling elements.

In a preferred embodiment of the linear guide unit according to the invention, a

-A-

A common retaining web arrangement is arranged between them, which secures the load-bearing rolling element rows in the engaged position with the respective load-bearing raceways of the bearing main body, and at least one channel section of the lubricant channel system leads to a rear side of the retaining web arrangement remote from the guide rail.

A further advantageous embodiment of a linear guide unit according to the invention with a retaining web arrangement has a mouth channel system connecting the channel section with the adjacent rows of rolling elements in a contact area between the rear side of the retaining web arrangement and the main bearing body.

Furthermore, it can advantageously be provided that the retaining web arrangement engages with a fastening rib in a fastening groove of the bearing main body, that the channel section opens into the fastening groove and that the opening channel system is formed by recesses in the retaining web arrangement in the area of the fastening rib and in areas lying between the fastening rib and the supporting rows of rolling elements.

It is also advantageous that the outlet channel system comprises a distribution channel which runs between a groove base of the fastening groove and a rib head surface of the fastening rib over at least part of the length of the supporting rolling element rows.

In addition, end channels of the outlet channel system can extend from the distribution channel at intervals along the axis.

A further advantageous embodiment consists in that the channel section runs essentially perpendicular to a plane which is defined by the centers of the rolling elements of the two adjacent load-bearing rolling element rows.

A linear guide unit according to the invention can also be designed in such a way that the main bearing body is U-shaped in a cross section orthogonal to the axis and is designed with two leg parts each opposite a side surface of the guide rail and connected by a web part, that two rolling element circuits are arranged in each of the leg parts and that the lubricant channel system is designed with at least one inflow connection in the area of the web part or in an area of a leg part adjacent to the web part.

In such a design, it is advantageously provided that the lubricant channel system in each of the leg parts comprises a first bore which leads from an outer surface of the web part to a respective channel section.

Advantageously, it is further provided that the lubricant channel system comprises a supply bore which runs essentially orthogonal to the axis and essentially parallel to the outer surface of the web part and is in cutting connection with the first bores.

However, there is still the problem that a symmetrical lubricant supply, as is easily achieved with the arrangement of the lubricant guide channels in the end plates,

sizable, is hardly possible with lubricant channels arranged in the main bearing body, since the upper surface of the guide carriage or the linear guide unit is generally not accessible but is covered by other components. It is therefore desirable to arrange the lubricant connection for the lubricant distribution system asymmetrically. However, due to the different lengths of the lubricant guide channels, this leads to different flow resistances for the lubricant, so that a uniform lubricant supply to the various load-transmitting rows of balls or rolling elements cannot be achieved. Uniform flow resistances of the various lubricant guide channels are, however, highly desirable, since in the case of uneven flow resistances, it must be ensured that the row of balls whose lubricant guide channel has the highest flow resistance is supplied with sufficient lubricant, which accordingly leads to an excess of lubricant in the remaining rows of balls and thus to increased lubricant consumption.

The invention is therefore also based on the object of providing a linear guide unit with an integrated lubricant channel system, comprising a rail with a cross-section that is essentially mirror-symmetrical to a plane of symmetry, and a bearing main body that is guided so as to be displaceable on the rail and has a cross-section that is essentially mirror-symmetrical to the same plane of symmetry and with at least two rolling element circuits arranged symmetrically to one another, wherein each rolling element circuit has a straight, load-transmitting row of rolling elements in engagement with an axially parallel, load-bearing raceway of the bearing main body and with an axially parallel, load-bearing raceway of the

Rail, so that with an asymmetrical or laterally arranged lubricant connection and a lubricant channel system arranged in the bearing main body, a uniform lubricant distribution of the lubricant to the individual opposing load-bearing rolling element rows is still possible.

Care should also be taken to design such a lubricant distribution system in such a way that it is simple and cost-effective to manufacture.

The solution to the problem is characterized in a linear guide unit as defined above by a channel system integrated into the bearing main body for supplying a lubricant, comprising a supply bore arranged in the bearing main body, closed on one side, at least two lubricant channels communicating with the supply bore, each leading to at least one load-bearing row of rolling elements, the connecting cross sections of which with the supply bore are equally spaced from the plane of symmetry, a sleeve arranged in the supply bore, closed on one side, the outside diameter of which is smaller than the inside diameter of the supply bore, so that a hollow cylindrical space is formed between the outside of the sleeve and the inside wall of the supply bore, and which has a transverse bore lying in the plane of symmetry, connecting the inner cavity of the sleeve to the space, and a lubricant connection connected to the inner cavity of the sleeve.

In the lubricant distribution system according to the invention, the inner cavity of the laterally

The sleeve connected to the lubricant connection initially carries the lubricant up to the symmetry plane of the linear guide unit, where the lubricant exits through a cross hole arranged in the sleeve into a hollow cylindrical space arranged between the outside of the sleeve and the inner wall of the supply hole. In this way, it is ensured that the lubricant has to travel the same distance from the cross hole arranged in the symmetry plane to the respective rows of balls, thus ensuring the same flow resistance, and the combination of supply hole and sleeve can be manufactured in a technically simple and cost-effective manner.

In a particularly preferred embodiment of the linear guide unit according to the invention, the rolling elements are balls.

To further simplify manufacturing, it is suggested that the axis of the supply hole is perpendicular to the plane of symmetry.

A preferred embodiment of the invention is characterized in that the lubricant channels each have a first bore extending from an upper surface into the bearing main body, the axis of the bore intersecting the axis of the supply bore.

A preferred embodiment of the invention is characterized in that the lubricant channels have a channel section adjoining the first bore.

A preferred embodiment of the invention is characterized in that the linear motion unit has four ball circuits which are arranged in pairs opposite one another symmetrically to one another, and in that the channel sections each open between two load-bearing rows of balls of the ball circuits arranged one above the other.

A preferred embodiment of the invention is characterized in that a part of the first bores, which partially form the lubricant channels and are located above the supply bore, is closed by a plug.

A preferred embodiment of the invention is characterized in that the sleeve arranged in the supply bore is centered at its end facing away from the lubricant connection by a centering surface arranged at the base of the supply bore.

A preferred embodiment of the invention is characterized in that the linear guide unit has end plates on which retaining webs are arranged, which are made in one piece with the latter and which secure the load-transmitting rows of balls in the engaged position with the load-bearing raceways of the main bearing body, whereby a gap is formed between the surface of each web facing the main bearing body and the main bearing body itself, which gap is connected to a channel section of one of the lubricant channels and serves to distribute the lubricant to the load-transmitting rolling elements.

A preferred embodiment of the invention is characterized in that the sleeve arranged in the supply bore is made of a round rod in which a

Internal bore extending from the end of the sleeve facing the lubricant connection to the transverse bore in the plane of symmetry.

A preferred embodiment of the invention is characterized in that the supply bore and the lubricant connection open into a vertically arranged side surface of the bearing main body.

A preferred embodiment of the invention is characterized in that the lubricant connection is fastened by means of a thread in the bearing main body.

A preferred embodiment of the invention is characterized in that the lubricant connection is a grease nipple.

A preferred embodiment of the invention is characterized in that the load-bearing raceways of the bearing main body are partially formed by inserts, between which a gap is arranged, which is connected to a respective channel section.

The invention is explained in more detail below using an embodiment shown in the drawing. The drawing shows:

Figure 1 is a view of a rolling bearing according to the invention, consisting of a guide carriage mounted on a rail, which is shown partially in section;

Figure 2 is a plan view of the linear guide unit from Figure 1;

Figure 3 is an enlarged vertical section through the bearing main body of the guide carriage of the linear guide unit shown in Figure ;

Figure 4 shows an enlarged cross section through the left leg of a bearing main body according to the invention for a linear guide unit according to Figure 1 and

Figure 5 is a view of an alternative embodiment of a linear guide unit according to the invention.

As Figure 1 shows, a linear guide unit 10 according to the invention consists of a main bearing body 12, which together with rolling elements in the form of balls 14 held in it forms a so-called guide carriage. The guide carriage runs on a rail 16. The main bearing body 12 is essentially U-shaped in a cross section perpendicular to the axis of the rail 16 and has a left leg 13L, a right leg 13R and a web 8 connecting these to one another.

The cross sections of the bearing main body 12 and the rail are mirror-symmetrical to a plane of symmetry S running perpendicular to the plane of the drawing. The balls are arranged or held in the bearing main body 12 in four ball circuits 18a-18d, which are arranged symmetrically to one another in pairs. Each ball circuit has a load-transmitting ball row 19a-19d, which is in engagement with an axially parallel, load-bearing raceway 20a-20d of the bearing main body 12 and with an axially parallel, load-bearing raceway 2la-21d of the rail 16. The balls of

Two load-bearing rows of balls arranged on each side of the plane of symmetry S are held by a web arrangement 22L, 22R, which extends perpendicularly to the plane of the drawing in Figure 1 and is connected to end sections 23 of the guide carriage shown in Figure 2.

In addition to a load-transferring row of balls, the ball circuits have two adjoining semicircular arcs (not shown in Figure 1), which are generally arranged in the end sections of the guide carriage, as well as a return ball row, so that the individual ball can rotate on an oval guide and, when the guide carriage is moved for a longer period, moves from the load-transferring row of balls into an arc, from there into the return ball row, until it finally re-enters the load-transferring row of balls.

Figure 3 shows a vertical section through the bearing main body along the line III-III in Figure 2, with the balls 14 and the web arrangement 22L omitted for the sake of clarity. A supply bore 24 is arranged in the bearing main body, the axis 26 of which runs in a plane parallel to the ball circuits and perpendicular to the plane of symmetry. As Figure 2 shows,

In the present embodiment, the axis 26 of the supply bore 24 is also perpendicular to the plane of symmetry S. Two lubricant channels 28L and 28R are connected to the supply bore 24, which are equally spaced from the plane of symmetry S and are connected to the supply bore 24. The lubricant channels 28L and 28R lead directly to the load-transferring rows of balls. The lubricant channels are

The present embodiment is made up of individual holes, which are explained in more detail below.

Two first vertical bores 29L and 29R arranged parallel to the plane of symmetry S cross the supply bore 2 arranged perpendicular to the plane of symmetry and thus create a connection. After the vertical bores 29L and 29R have been made, the area of these bores above the supply bore 24 is drilled out to a larger diameter and the resulting larger partial bores 3OL and 3OR are closed with plugs not shown here.

Between the load-bearing raceways of the bearing main body 20c and 20d arranged in the left leg 13L, a channel section in the form of a transverse bore 3 2L is arranged in the bearing main body 12, which meets the vertical bore 29L in the interior of the bearing main body. Accordingly, a corresponding channel section in the form of a transverse bore is arranged mirror-symmetrically on the right side of the symmetry plane S, between the load-bearing raceways 20a and 20b of the bearing main body 12, which meets the vertical bore 29R in the interior of the bearing main body.

Since the partial bores 3OL and 3OR are closed by plugs (not shown), a guide system for supplying a lubricant is created in which lubricant supplied to the supply bore 24 is guided through the lubricant channels 28L and 28R and exits near the load-transferring rows of balls. As Figure 1 shows, the webs 22 are arranged in such a way that between the surface of the web facing the bearing main body and the surface

of the bearing main body itself, a mouth channel system 34 in the form of a gap is formed, which connects the outlet opening of the channel section 32 with an upper load-bearing row of balls 19a, 19c and a lower load-bearing row of balls 19b, 19d.

In Figure 4, the orifice channel system 34 of the left leg 13L, which is arranged between the rear of the web arrangement 22L and the bearing main body 12 and connects the channel section 32L with the adjacent rolling element or ball rows 19c and 19d, is shown on an enlarged scale. The retaining web 22L, which is made of plastic and connected to the end plates 23 (Figure 2), has a fastening rib 60 with which it engages in a fastening groove 62 of the bearing main body 12.

The height of the rib is slightly smaller than the depth of the fastening groove, so that between a rib head surface 61 of the fastening rib 60 and the groove base 63 of the fastening groove 62 of the bearing main body 12, a distribution channel 35 in the form of a gap is formed, which in Figure 4 extends perpendicular to the plane of the drawing and runs over at least part of the length of the supporting rolling element rows.

The channel section 32L communicating with the lubrication channel system opens into the fastening groove 62 and the lubricant flowing through the channel section 32L can be distributed through the distribution channel 35 in the longitudinal direction of the load-transmitting rows of balls. The distribution channel 35, which is formed in the form of a gap, is connected along the axis to end channels 64 of the outlet channel system, which are formed in the form of recesses 66 in the area of the fastening rib 60 of the holding web arrangement 22.

The lubricant supplied through the supply bore 24 (Figure 1) flows through the vertical first bores 29L and 29R to the channel sections 32L and 32R, then distributes through the distribution channels 35 and flows through the end channels 64 of the orifice channel system 34 to the load-transmitting rolling element rows 19a-19d.

As can be seen from Figure 4, sealing lips 70 can be provided above the upper rolling element or ball rows and below the lower ball rows between the bearing main body 12 and the rail 16, which prevent the escape of lubricant from the area of the load-transmitting ball rows and thus further reduce lubricant consumption.

As Figure 3 shows, the supply bore 24 on the right side of the bearing main body continues into a larger bore 36, which has a thread 38 and serves as a lubricant connection. For example, a grease nipple or a hose feed for a lubricant can be attached to the thread 38. The arrangement described so far, consisting of the lubricant connection 36, the adjoining supply bore 24 and the lubricant channels 28L and 28R leading to the load-transmitting rows of balls, consisting of the vertical bores 29L, 29R, 32L, 32R and the gaps 34L and 34R, would in principle already be suitable for directing lubricant from an asymmetrically arranged lubricant connection 36 to the four load-transmitting rows of balls. However, due to the asymmetrical arrangement of the lubricant connection 36 and the resulting longer paths that the lubricant has to travel to the left rows of balls compared to the right rows of balls and the resulting different flow resistances,

an uneven distribution of lubricant can occur. A sleeve 40 is therefore arranged in the supply bore 24, which serves to even out the flow resistance. The sleeve 40 is closed at its end 4OL facing away from the lubricant connection 36 and has an outer diameter that is smaller than the inner diameter of the supply bore 24, so that an annular cylindrical space 42 is formed between the outside of the sleeve 40 and the inner wall of the supply bore 24. The sleeve 40 is guided at its left end 4OL in a centering bore 44 in such a way that it is arranged concentrically in the supply bore 24, whereby it is clamped by the lubricant connection 36 (not shown). The sleeve 40 has an axially extending bore 4 6 and a transverse bore 4 8 arranged transversely thereto, which comes to lie in the plane of symmetry S when the sleeve is inserted into the supply bore of the bearing main body.

With the sleeve inserted, the lubricant flow is as follows: The lubricant enters through the lubricant connection 36 and is initially guided through the axial inner bore 46 of the sleeve until it exits through the transverse bore 48 of the sleeve 40 in the plane of symmetry S and fills the ring-cylindrical space 42 arranged between the outside of the sleeve and the inner wall of the supply bore. As the lubricant is initially guided through the inner bore of the sleeve and the transverse bore 48 to the plane of symmetry S, it spreads from here evenly to the left and right in the space 42 with the same flow resistance until it reaches the vertical bores 29L and 29R and fills them. From here it reaches the channel sections 32L and 32R and is guided from their outlet opening through the muzzle channel system or the gaps 34L and 34R directly to the load-transferring rows of balls 19a-19d.

As Figure 3 shows, where the structural conditions allow it, a central lubricant connection 37 arranged in the plane of symmetry can be provided instead of the asymmetrical lubricant connection 36, which is connected to a horizontal supply bore 24. In such an embodiment, the sleeve 40 used to even out the lubricant flow can of course be omitted.

The invention enables a direct, uniform and economical supply of lubricant to the load-transmitting rolling element rows of a linear guide unit.

Figure 5 shows an alternative embodiment of a linear guide unit according to the invention. The load-bearing raceways 20a-20d of the bearing main body are partially formed by an insert piece 50, which may be rocking, and which has one or more bores 52. The transverse bore 32R of each lubricant channel 28R guides the lubricant to the bores 52R. In this embodiment too, a channel 54 running perpendicular to the plane of the drawing can be arranged in the apex of the insert piece 50, from which the bores 52R extend, so that a single or a small number of channel sections 32R are sufficient.

Claims (27)

-1-claims 1. Linear guide unit, comprising a rail (16) with an axis and a bearing main body (12) which is guided displaceably in the axial direction of this rail by closed rolling element circuits (18a-18d), wherein load-bearing rolling element rows (19a-19d) of two rolling element circuits are adjacent to one another and on the one hand rest against a load-bearing raceway (21a-21d) of the rail and on the other hand against a load-bearing raceway (20a-20d) of the main bearing body, wherein a lubricant channel system for supplying the load-bearing rolling element rows (I9a-19d) is further provided within the bearing main body (12), of which at least one discharge opening is located in the region of the axial longitudinal extension of the load-bearing rolling element rows,
characterized, that at least one lubricant channel (28R, 28L) of the lubricant channel system opens into an area between the two adjacent load-bearing rolling element rows (19a-19d). 2. Linear guide unit according to claim 1, characterized in that that both adjacent load-bearing rolling element rows (19a, 19b; 19c, 19d) are assigned a common retaining web arrangement (22L, 22R) housed between them, which secures these load-bearing rolling element rows in the engaged position with the respective load-bearing raceways (20a-20d) of the bearing main body (12) and that at least one channel section (32L, 32R) leads to a rear side of the retaining web arrangement (22L, 22R) remote from the guide rail (16). -2- 3. Linear guide unit according to claim 2 , characterized in that in a contact area between the rear side of the retaining web arrangement (22L, 22R) and the bearing main body (12) a mouth channel system (34) is formed connecting the channel section (32L, 32R) with the adjacent rows of rolling elements (I9a-19d). 4. Linear guide unit according to claim 3 , characterized in that the retaining web arrangement (22L, 22R) engages with a fastening rib (60) in a fastening groove (62) of the bearing main body (12), that the channel section (32R, 32L) opens into the fastening groove (62) and that the mouth channel system (34) is formed by recesses (66) in the retaining web arrangement (22) in the region of the fastening rib (60) and in areas between the fastening rib and the supporting rows of rolling elements. 5. Linear guide unit according to claim 4 , characterized in that that the outlet channel system (34) comprises a distribution channel (35) which runs between a groove base (63) of the fastening groove (62) and a rib head surface (61) of the fastening rib (60) over at least part of the length of the supporting rolling element rows. 6. Linear guide unit according to claim 5, characterized in that that end channels (64) of the outlet channel system extend from the distribution channel (35) at intervals along the axis. -3- 7. Linear guide unit according to one of claims 1 to 6, characterized in that the channel section (32R,32L) extends substantially perpendicular to a plane which is defined by the centers of the rolling elements of the two adjacent load-bearing rolling element rows. 8. Linear guide unit according to one of claims 1 to 7, characterized in that the bearing main body is U-shaped in a cross-section orthogonal to the axis and is designed with two leg parts (13L, 13R) each opposite a side surface of the guide rail and connected by a web part (8), that two rolling element circuits (18a, 18b; 18c, 18d) are arranged in each of the leg parts (13L, 13R) and that the lubricant channel system is designed with at least one inflow connection (36, 37) in the area of the web part (37) or in an area of a leg part adjacent to the web part (36). 9. Linear guide unit according to claim 8 , characterized in that the lubricant channel system in each of the leg parts comprises a first bore (29L, 29R) which leads from an outer surface of the web part (8) to a respective channel section (32L, 32R). 10. Linear guide unit according to claim 8 or 9, characterized in that the lubricant channel system comprises a supply bore (24) which runs essentially orthogonal to the axis and essentially parallel to the outer surface of the web part and is in cutting communication with the first bores (29L, 29R). -4- 11. Linear guide unit according to claim 10,
characterized, that the supply bore (24) contains a distributor device (40) which branches the lubricant supply to the respective supporting rolling element rows (19a-19d) of the two leg parts at a middle point (S) of the web part and ensures approximately equal flow conditions from the branch point to the respective supporting rolling element rows of the two leg parts
ensure. 12. Linear guide unit according to claim 10,
characterized, that a lubricant connection (37) is provided in the region of the branching point, which is open towards the outer surface of the web part. 13. Linear guide unit according to claim 10,
characterized, that the distributor device comprises a sleeve (40) extending in the longitudinal direction of the supply bore (24) and extending substantially over the entire length of the
supply bore (24), that this sleeve is connected to an inflow connection (36) in the region of one end of the supply bore (24) and that the sleeve (40) in the area of the branching point
at least one opening (48) which extends into a through the supply bore (24) and the sleeve (40)
limited space (42). -5- 14. Linear guide unit with integrated lubricant channel system, comprising a rail (16) with a cross-section that is essentially mirror-symmetrical to a plane of symmetry (S), and a bearing main body (12) that is guided so as to be displaceable on the rail and has a cross-section that is essentially mirror-symmetrical to the same plane of symmetry (S) and with at least two rolling element circuits (18a-18d) arranged symmetrically to one another, each rolling element circuit having a straight, load-transmitting rolling element row (19a-19d) in engagement with an axially parallel, load-bearing raceway (20a-20d) of the bearing main body (12) and with an axially parallel, load-bearing raceway (21a-21d) of the rail (16), marked by, a channel system integrated into the bearing main body (12) for supplying a lubricant, comprising a supply bore (24) arranged in the bearing main body (12) and closed on one side, at least two lubricant channels (28L, 28R) communicating with the supply bore (24) and each leading to at least one load-bearing row of rolling elements (19a-19d), the connecting cross sections of which with the supply bore (24) are equally spaced from the plane of symmetry (S), a sleeve (40) arranged in the supply bore (24), closed on one side, the outer diameter of which is smaller than the inner diameter of the supply bore, so that an annular cylindrical space (42) is formed between the outside of the sleeve (40) and the inner wall of the supply bore (24), and which has a transverse bore (48) lying in the plane of symmetry (S) and connecting the inner cavity (46) of the sleeve to the space (42), and -6- a lubricant connection (36) connected to the inner cavity (46) of the sleeve (42). 15. Linear guide unit according to claim 14, characterized in that the rolling elements are balls (14). 16. Linear guide unit according to claim 14 or 15, characterized in that the axis (26) of the supply bore (24) is perpendicular to the plane of symmetry (S). 17. Linear guide unit according to one of claims 14 to 16, characterized in that the lubricant channels (28L, 28R) each have a first bore (29L, 29R) which extends from an upper surface into the bearing main body (12), the axis of the bore intersecting the axis (26) of the supply bore (24). 18. Linear guide unit according to claim 17, characterized in that the lubricant channels (28L, 28R) have a channel section (32L, 32R) adjoining the first bore (29L, 29R). 19. Linear guide unit according to claim 18, characterized in that the linear guide unit has four ball circuits (18a-18d) which are arranged in pairs opposite one another symmetrically to one another, and that the channel sections (32L, 32R) each open between two load-bearing ball rows (19a-19d) of the ball circuits (18a-18d) arranged one above the other. -7- 20. Linear guide unit according to one of claims 17 to 19, characterized in that that a part (3OL,30R) of the first bores (29L,29R) which partially form the lubricant channels (28L,28R) and which is located above the supply bore (24) is closed by a plug in each case. 21. Linear guide unit according to one of claims 14 to 20, characterized in that that the sleeve (40) arranged in the supply bore (24) is centered at its end (40L) facing away from the lubricant connection (36) by a centering surface (44) arranged at the base of the supply bore (24). 22. Linear guide unit according to one of claims 14 to 21, characterized in that that the linear roller bearing has end plates (23) on which retaining webs (22) are arranged in one piece with these, which secure the load-transmitting ball rows (19a-19d) in the engaged position with the load-bearing raceways (20a to 20d) of the bearing main body (12), whereby a gap (34L, 34R) is formed between the surface of a web (22) facing the bearing main body (12) and the bearing main body (12) itself, which gap is connected to a channel section (32L, 32R) of one of the lubricant channels (28L, 28R) and serves to distribute lubricant to the load-transmitting rolling elements (14). 23. Linear guide unit according to one of claims 14 to 22, characterized in that that the sleeve (40) arranged in the supply bore (24) is made of a round rod in which an inner bore (46) is provided, which extends from the -8th- The end (40R) of the sleeve (40) facing the lubricant connection (36) extends to the transverse bore (48) lying in a plane of symmetry (S). 24. Linear guide unit according to one of claims 14 to 23, characterized in that the supply bore (24) and the lubricant connection (36) open into a vertically arranged side surface of the bearing main body (12). 25. Linear guide unit according to claim 24, characterized in that the lubricant connection is fastened in the bearing main body (12) by means of a thread (38). 26. Linear guide unit according to claim 25, characterized in that the lubricant connection (36) is a grease nipple. 27. Linear guide unit according to one of claims 14 to 26, characterized in that the load-bearing grooves (20a-20d) of the bearing main body (12) are partially formed by inserts (50a, 50b), between which a gap (52L, 52R) is arranged, which is connected to a respective transverse bore (32L, 32R).