Lubrication structure for bearings

Abstract

A lubrication structure of the present disclosure comprises: a hollow housing; an outer bearing with an outer ring held against an inner circumferential surface of the housing; a first rotating body, which is hollow and attached to an inner ring of the outer bearing; an inner bearing with an outer ring held against an inner circumferential surface of the first rotating body; and a second rotating body attached to an inner ring of the inner bearing. The housing has a first lubrication channel into which lubricant, which is to be supplied to the inner bearing, is introduced. A downstream side of the first lubrication channel communicates with a first sealed space, which is sealed between the housing and the first rotating body. The first rotating body has a second lubrication channel with an upstream side that communicates with the first sealed space.A downstream side of the second lubrication path communicates with, or is connected to, a second sealed chamber located between the first and second rotating bodies. The inner bearing is situated within this second sealed chamber.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a lubricating structure for supplying a lubricant to a bearing. STATE OF THE ART

[0002] Patent Document 1 discloses an injection molding machine that can move an injection screw by pressing a push plate through a linear motion resulting from the conversion of the rotational motion of a ball screw combined with a ball nut. This injection molding machine has the following configuration.

[0003] A screw sleeve or protective sleeve provided with the injection screw is arranged via a bearing in a through hole of the push plate. This allows the screw sleeve to rotate relative to the push plate. The ball screw is arranged via a bearing on an inner peripheral portion of the screw sleeve. This allows the ball screw to rotate relative to the screw sleeve. In the injection molding machine with this configuration, the injection screw rotates during measuring and kneading, and the ball screw rotates during injection. Therefore, an inner ring and an outer ring of the bearing between the ball screw and the screw sleeve rotate during molding. Citation listPatent document

[0004] Patent Document 1: Japanese Unexamined Patent Application, Publication No. H8-192447 DISCLOSURE OF THE INVENTION Problems to be solved by the invention

[0005] Recently, a bearing located between a ball screw and a screw sleeve is often used under harsh conditions. Therefore, it is necessary to regularly lubricate (supply with lubricant) the bearing between the ball screw and the screw sleeve to improve durability.

[0006] In a case where a bearing arranged between the ball screw and the screw sleeve has the above-described configuration in which the inner and outer rings rotate, and is to be lubricated by an automatic lubricator via a hose, the hose rotates, preventing automatic lubrication using the hose. To solve this problem, it is conceivable to manually lubricate the bearing using a grease gun while the injection molding machine is stopped.

[0007] However, in this case, it is necessary to stop the injection molding machine, resulting in a reduction in the operating rate or speed of the injection molding machine. Furthermore, manual lubrication, for example, leads to the problem of forgetting to lubricate and the problem of the lubrication process being difficult. Therefore, there is a need for a lubrication structure with a simple configuration that allows easy lubrication of a bearing whose inner and outer rings rotate. Means to solve the problems

[0008] One aspect of the present disclosure relates to a lubricating structure for a bearing, the lubricating structure including: a housing having a hollow shape; an outer bearing having an outer ring held on an inner peripheral surface of the housing; a first rotating body having a hollow shape and fixed to an inner ring of the outer bearing; an inner bearing having an outer ring held on an inner peripheral surface of the first rotating body; and a second rotating body fixed to an inner ring of the inner bearing. The housing includes a first lubrication path through which a lubricant to be supplied to the inner bearing flows. The first lubrication path has a downstream end communicating with a first sealed space sealed and formed between the housing and the first rotating body.The first rotating body includes a second lubrication path with an upstream end communicating with the first sealed space. The second lubrication path has a downstream end communicating with a second sealed space formed between the first rotating body and the second rotating body. The inner bearing is disposed in the second sealed space. Effects of the invention

[0009] According to the aspect, a lubrication structure can be provided that has a simple configuration and enables easy lubrication of a bearing whose inner and outer rings rotate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a right side view of an example of an injection molding machine to which a lubricating structure for a bearing according to a first embodiment of the present invention is applied, showing a part of the injection molding machine and a part of the lubricating structure in cross section; Fig. 2 is a right side view of a modification of the lubricating structure for a bearing according to the first embodiment, showing a part of the lubricating structure in cross section; Fig. 3 is a right side view of a lubricating structure for a bearing according to a second embodiment of the present invention, showing a part of the lubricating structure in cross section; Fig. 4 is a right side view of a modification of the lubricating structure for a bearing according to the second embodiment, showing a part of the lubricating structure in cross section; Fig. 5 is a right side view of a lubricating structure for a bearing according to a third embodiment of the present invention, showing a part of the lubricating structure in cross section; and Fig. 6 is a right side view of a modification of the lubricating structure for a bearing according to the third embodiment, showing a part of the lubricating structure in cross section. PREFERRED MODE FOR CARRYING OUT THE INVENTION

[0010] A lubrication structure for a bearing according to one aspect of the present disclosure will be described below with reference to the drawings. A lubrication structure for a bearing according to a first embodiment will be described with reference to Fig. 1. The lubrication structure for a bearing includes a housing 1, an outer bearing 2, a first rotating body 3, an inner bearing 4, and a second rotating body 5. A case in which the present invention is applied to an injection molding machine 6 is described. Note that the device to which the present invention is applicable is not limited to the injection molding machine 6.

[0011] The injection molding machine 6 includes a front plate 7 and a back plate 8 arranged to face each other, guide rods 9 connecting the front plate 7 and the back plate 8, the housing 1 provided to be slidable along the guide rods 9, the first rotating body 3 rotatable with respect to the housing 1 and immovable in the axial direction, an injection screw 10 arranged on the first rotating body 3, the second rotating body 5 rotatable with respect to the first rotating body 3 and immovable in the axial direction, and a ball nut 11 arranged on the back plate 8. The injection molding machine 6 can move the injection screw 10 by pressing or pushing the housing 1 by means of a linear movement resulting from a conversion of the rotational movement of the second rotation body 5 screwed into the ball nut 11.

[0012] The front plate 7 has a plate shape. The front plate 7 is provided with an injection cylinder 12. The back plate 8 has a plate shape. The back plate 8 has a through hole 13 penetrating it in the thickness direction. The front plate 7 and the back plate 8 are connected to each other by the plurality of guide rods 9 having a rod shape. In particular, the back plate 8 is provided at one axial end portion (the right end portion in Fig. 1) of each guide rod 9, and the front plate 7 is fixed to the other axial end portion (the left end portion in Fig. 1) of each guide rod 9, whereby the front plate 7 and the rear plate 8 are connected to each other in a facing state.

[0013] The housing 1 is in the shape of a thick plate. The housing 1 has a plurality of insertion holes 14 penetrating it in the thickness direction (which is the same as the axial direction of the guide rods 9). The housing 1 is arranged on the guide rods 9, while the guide rods 9 pass through the insertion holes 14. In the state where each guide rod 9 passes through the corresponding insertion hole 14, a tubular bushing 15 is arranged between the inner peripheral surface of the insertion hole 14 and the outer peripheral surface of the guide rod 9. In this way, the housing 1 is arranged on the guide rods 9 so as to be slidable along the axial direction of the guide rods 9.

[0014] The housing 1 has a through-hole 16 penetrating it in the thickness direction. The through-hole 16 is located substantially in the center of the housing 1. In the example shown, the through-hole 16 has a stepped portion. Specifically, the through-hole 16 includes a small-diameter hole 17 near one axial end and a large-diameter hole 18 near the other axial end. In other words, the housing 1 in which the through-hole 16 is formed has a hollow shape with an inner peripheral surface.

[0015] The first rotating body 3 includes a main body 19 having a columnar shape and a pressing portion 20 for pressing the inner bearings 4, which will be described later. The main body 19 has a circular, columnar shape with a stepped portion and includes a large-diameter portion 21 near one axial end (the right end in Fig. 1) of the main body 19 and a small-diameter portion 22 adjacent to the large-diameter portion 21. The main body 19 has a recess 23 in the end surface of one axial end, which has a circular shape when viewed from behind. The recess 23 opens at one axial end of the main body 19. In the example shown, the recess 23 has a stepped portion and includes a large-diameter hole portion 24 near one axial end and a small-diameter hole portion 25 near the other axial end. In other words, the first rotary body 3 in which the recess 23 is formed has a hollow shape with an inner peripheral surface. The injection screw 10 is fixed to the other axial end of the main body 19 with a bolt or the like.The pressing portion 20 has a plate shape and has a through hole 26 penetrating it in the thickness direction. The first rotating body 3 is rotatably supported by the housing 1 via the outer bearing 2. In the first embodiment, the outer bearing 2 is, for example, a ball bearing.

[0016] The outer bearing 2 includes a first bearing 27 and a second bearing 28 that are adjacent to each other, an outer ring spacer 31 that has a ring shape and connects an outer ring 29 of the first bearing 27 and an outer ring 30 of the second bearing 28, and an inner ring spacer 34 that has a ring shape and connects an inner ring 32 of the first bearing 27 and an inner ring 33 of the second bearing 28. A cylindrical gap is formed between the outer ring spacer 31 and the inner ring spacer 34. The outer bearing 2 with this configuration is arranged in the housing 1 such that the outer ring 29 of the first bearing 27 and the outer ring 30 of the second bearing 28 are held on the inner peripheral surface of the large-diameter hole 18. In the state in which the outer bearing 2 is arranged in the housing 1, the outer ring 29 of the first bearing 27, which is located near one axial end (the right end in Fig. 1) of the outer bearing 2 is in contact with the stepped portion between the large-diameter hole 18 and the small-diameter hole 17, whereas the outer ring 30 of the second bearing 28, located near the other axial end of the outer bearing 2, is in contact with a pressing portion 36 provided on the housing 1. The pressing portion 36 has a plate shape and is fixed with a bolt or the like to the other axial end surface of the housing 1. The pressing portion 36 has a through hole 37 penetrating it in the thickness direction. In this way, the outer rings (29, 30) of the outer bearing 2 are held on the inner peripheral surface of the housing 1, which has a hollow shape.

[0017] The main body 19 of the first rotating body 3 is supported by the inner ring 32 of the first bearing 27 and the inner ring 33 of the second bearing 28. In this case, the outer peripheral surface of the small-diameter portion 22 of the main body 19 is fixed to the inner ring 32 of the first bearing 27 and the inner ring 33 of the second bearing 28. In the state where the first rotating body 3 is supported by the outer bearing 2, the inner ring 32 of the first bearing 27 is in contact with the stepped portion between the large-diameter portion 21 and the small-diameter portion 22, and the inner ring 33 of the second bearing 28 is in contact with an annular pressing portion 72 provided on the first rotating body 3. The pressing portion 72 is fixed to the first rotating body 3 while the first rotating body 3 penetrates therethrough. In this way, the first rotating body 3 is fastened to the inner rings (32, 33) of the outer bearing 2.In the state in which the first rotary body 3 is fixed to the outer bearing 2, the other axial end portion (the left end portion in . Fig. 1) of the first rotary body 3 through the opening at the other axial end of the through hole 16 of the housing 1 and the through hole 37 of the pressing portion 36.

[0018] The second rotation body 5 has a columnar shape. In the example shown, the other axial end portion (the left end portion in Fig. 1) The second rotating body 5 has a columnar shape with a stepped portion and includes a large-diameter portion 39 and a small-diameter portion 40. The second rotating body 5 is rotatably supported by the first rotating body 3 via the inner bearings 4. Each inner bearing 4 is, for example, a ball bearing. While a plurality of inner bearings 4 are used in the first embodiment, only one inner bearing 4 may be used.

[0019] The plurality of inner bearings 4 are arranged in contact with each other on the inner peripheral surface of the recess 23 of the first rotating body 3. In this case, an outer ring 41 of each inner bearing 4 is held on the inner peripheral surface of the large-diameter hole portion 24 of the recess 23, whereby the inner bearings 4 are arranged on the first rotating body 3. In the state where the plurality of inner bearings 4 are arranged on the first rotating body 3, the outer ring 41 of the inner bearing 4 located inward of the recess 23 is in contact with the stepped portion between the large-diameter hole portion 24 and the small-diameter hole portion 25, and the outer ring 41 of the inner bearing 4 near the opening of the recess 23 is in contact with the pressing portion 20 provided on the main body 19.The pressing portion 20 is fixed with a bolt or the like to the end surface of one axial end of the main body 19. In this way, the outer rings 41 of the inner bearings 4 are held on the inner peripheral surface of the first rotating body 3, which has a hollow shape.

[0020] The small-diameter portion 40 of the second rotating body 5 is held on an inner ring 43 of each inner bearing 4 in a state where the second rotating body 5 passes through the through hole 26 of the pressing portion 20 of the first rotating body 3. In this case, the outer peripheral surface of the small-diameter portion 40 of the second rotating body 5 is fixed to the inner rings 43 of the inner bearings 4. In the state where the second rotating body 5 is held by the plurality of inner bearings 4, the inner ring 43 of the inner bearing 4 near the opening of the recess 23 is in contact with the stepped portion between the small diameter portion 40 and the large diameter portion 39, and the inner ring 43 of the inner bearing 4 located inward in the recess 23 is in contact with an annular pressing portion 45 disposed on the small diameter portion 40 of the second rotating body 5.The pressing portion 45 is fixed to the other axial end portion of the small-diameter portion 40, while the small-diameter portion 40 is inserted therein. Thus, the second rotating body 5 is fixed to the inner rings of the inner bearings 4. In the first embodiment, the inner bearings 4 and the outer bearing 2 are arranged in a double configuration inside and outside.

[0021] The second rotating body 5 has an external thread formed on its outer peripheral surface except for the other axial end portion. The second rotating body 5 is screwed into the ball nut 11 provided on the back plate 8. The ball nut 11 is non-rotatably fixed in the through hole 13 of the back plate 8. The second rotating body 5, which is screwed into the ball nut 11 provided on the back plate 8, passes through the through hole 13 of the back plate 8. That is, one axial end portion of the second rotating body 5 protrudes from the through hole 13 of the back plate 8. One axial end portion of the second rotating body 5 penetrates an annular load cell 46 arranged on the back plate 8. The load cell 46 is fixed to the back plate 8 with a bolt or the like.

[0022] Next, an operation of the injection molding machine 6 will be described. The injection molding machine 6 is configured so that only the injection screw 10 rotates during measuring and kneading, and only the second rotating body 5 rotates during injection. Therefore, the injection molding machine 6 includes a motor 47 that rotates the first rotating body 3 to which the injection screw 10 is attached, and a motor 48 that rotates the second rotating body 5. The motor 47 is arranged on the housing 1. The motor 47 has a drive shaft and a drive pulley 49 fixed to the drive shaft. A belt 51 extends between and is wound around the drive pulley 49 provided on the motor 47 and a driven pulley 50 attached to the other axial end portion of the first rotating body 3.The motor 48 is provided on the housing 1 such that the first rotating body 3 is arranged between the motor 47 and the motor 48. The motor 48 has a drive shaft and a drive pulley 52 fixed to the drive shaft. A belt 54 extends between and is wound around the drive pulley 52 provided on the motor 48 and a driven pulley 53 provided on the second rotating body 5.

[0023] With this configuration, when measuring and kneading is performed, the motor 47 is driven in a state where the motor 48 is stopped, allowing the injection screw 10 to rotate. By rotating the injection screw 10, the measuring and kneading is performed, and molten resin is supplied to the tip of the injection cylinder 12. When injection is performed, the second rotating body 5 is rotated by driving the motor 48 in a state where the motor 47 is stopped. By rotating the second rotating body 5, the housing 1 is moved toward the injection cylinder 12, and the injection screw 10 is moved into the injection cylinder 12, allowing injection to be performed.

[0024] The bearing lubrication structure according to the first embodiment is applied to the injection molding machine 6 described above. The bearing lubrication structure includes a housing 1 having a hollow shape, an outer bearing 2 having an outer ring held on an inner peripheral surface of the housing 1, a first rotating body 3 having a hollow shape and fixed to an inner ring of the outer bearing 2, inner bearings 4 each having an outer ring held on an inner peripheral surface of the first rotating body 3, and a second rotating body 5 fixed to an inner ring of each inner bearing 4. The housing 1, the outer bearing 2, the first rotating body 3, the inner bearings 4, and the second rotating body 5 each have the configurations described above.

[0025] As in Fig. 1, the housing 1 has a first lubrication path 55 through which a lubricant to be supplied to the inner bearings 4 flows. An upstream opening of the first lubrication path 55 opens to the outside of the housing 1. The upstream opening of the first lubrication path 55 is provided with a lubrication port 56, which is constituted by a grease nipple or the like. The lubrication port 56 is connected to a lubricating device that automatically supplies the lubricant. A downstream end of the first lubrication path 55 is connected to a first sealed space 57, which is sealed and formed between the housing 1 and the first rotating body 3. The first sealed space 57 is formed by sealing openings of a cylindrical gap between the inner peripheral surface of the housing 1 and the outer peripheral surface of the first rotating body 3 with sealing members.

[0026] The sealing members include a first sealing member 58 provided on an outer side of the first bearing 27 and a second sealing member 59 provided on an outer side of the second bearing 28. The first sealing member 58 seals an axial end (the right end in Fig. 1) the cylindrical gap between the outer ring spacer 31 and the inner ring spacer 34. The second sealing member 59 seals the other axial end of the cylindrical gap between the outer ring spacer 31 and the inner ring spacer 34. The cylindrical gap between the outer ring spacer 31 and the inner ring spacer 34 is sealed, thereby forming the first sealed space 57. In the case where the cylindrical gap sealed by the first sealing member 58 and the second sealing member 59 constitutes the first sealed space 57, the downstream end of the first lubrication path 55 communicates with the first sealed space 57 via an external through-hole 60 formed in the outer ring spacer 31.

[0027] As in Fig. 1, the first rotating body 3 has a second lubrication path 61 through which the lubricant flowing from the first lubrication path 55 via the first sealed space 57 flows. An upstream end of the second lubrication path 61 communicates with or is connected to the first sealed space 57. In the first embodiment, the cylindrical gap between the outer ring spacer 31 and the inner ring spacer 34 forms the first sealed space 57. Therefore, the upstream end of the second lubrication path 61 communicates with the first sealed space 57 via an inner through-hole 62 formed in the inner ring spacer 34.

[0028] A downstream end of the second lubricating path 61 communicates with or is connected to a second sealed space 63, which is sealed and formed between the first rotating body 3 and the second rotating body 5. The second sealed space 63 is formed by sealing an opening of a cylindrical gap between the inner peripheral surface of the first rotating body 3 and the outer peripheral surface of the second rotating body 5 with a sealing member 64. The sealing member 64 is arranged near the opening of the recess 23 and seals the gap between the inner peripheral surface of the first rotating body 3 and the outer peripheral surface of the second rotating body 5. The sealing member 64 has an annular shape and is arranged between the inner peripheral surface of the pressing portion 20 of the first rotating body 3 and the outer peripheral surface of the large-diameter portion 39 of the second rotating body 5.The sealing member 64 is a known oil seal, but is not limited thereto. The second sealed space 63 thus formed has the inner bearings 4 arranged therein.

[0029] As in Fig. 1, the first rotating body 3 penetrates the housing 1 and therefore has an exposed surface 65 exposed from the housing 1. Typically, the exposed surface 65 is the outer peripheral surface of the pressing portion 20 of the first rotating body 3. The first rotating body 3 has a drain path 66 through which the lubricant in the second sealed space 63 is drained to the outside of the housing 1. The drain path 66 is formed, for example, in the pressing portion 20 of the first rotating body 3. The drain path 66 is a path through which the lubricant that has passed through the inner bearings 4 is drained. Therefore, an upstream end of the drain path 66 communicates with a space between the inner bearing 4 and the sealing member 64. The drain path 66 has an outlet opening at the exposed surface 65.

[0030] In the lubricating structure of the first embodiment, the lubricant supplied from the lubricating device flows through the first lubricating path 55 into the first sealed space 57. The lubricant passes from the first sealed space 57 through the second lubricating path 61 to flow into the second sealed space 63. In this way, the lubricant is supplied to the inner bearings 4. Thereafter, the lubricant is discharged to the outside of the housing 1 through the discharge path 66. Thus, the lubricating structure according to the first embodiment has a simple configuration, facilitates lubrication when the injection molding machine 6 is in operation, and is particularly suitable for lubrication automation.

[0031] In the case of the lubricating structure of the first embodiment, the outlet of the discharge path 66 opens at the exposed surface 65. Thus, the lubricating structure of the first embodiment has a simple configuration compared to a configuration in which a lubricant is discharged via the housing 1.

[0032] Next, a modification of the lubrication structure for a bearing of the first embodiment will be described with reference to Fig. 2. Components denoted by the same reference numerals as those in the first embodiment perform the same functions as in the first embodiment, and their descriptions will be omitted below. The lubrication structure of the present modification includes a plurality of first lubrication paths 55 and a plurality of second lubrication paths 61.

[0033] As in Fig. As shown in FIG. 2, the lubricating structure according to the present modification includes two first lubrication paths 55, 55 and second lubrication paths 61, 61 corresponding to the two first lubrication paths 55, 55, respectively. The two first lubrication paths 55, 55 are provided at positions facing each other with the first rotating body 3 interposed therebetween. The two second lubrication paths 61, 61 are provided at positions facing each other with the first rotating body 3 interposed therebetween. Accordingly, two outer through-holes 60, 60 are formed in the outer ring spacer 31, and two inner through-holes 62, 62 are formed in the inner ring spacer 34.

[0034] In the lubrication structure of the present modification, a lubricant is supplied to the second sealed space 63 through the two lubrication paths. Thus, according to the lubrication structure of the present modification, the lubricant can be efficiently supplied to the second sealed space 63.

[0035] Next, a lubricating structure for a bearing according to a second embodiment of the present invention will be described with reference to Fig. 3. Components denoted by the same reference numerals as those in the first embodiment perform the same functions as in the first embodiment, and their descriptions will be omitted below. The lubricating structure of the second embodiment includes a first sealed space 57 with a different configuration than that of the first embodiment.

[0036] As in Fig. As shown in Figure 3, a through-hole 16 of a housing 1 has a stepped portion. The through-hole 16 includes a small-diameter hole 67 near one axial end of the through-hole 16 and a large-diameter hole 69 near the other axial end of the through-hole 16.

[0037] A plurality of outer bearings 2 are arranged in contact with each other in the large-diameter hole 69 of the through-hole 16. In this case, an outer ring 79 of each outer bearing 2 is held on an inner peripheral surface of the large-diameter hole 69, thereby arranging the outer bearings 2 in the housing 1. In the state where the plurality of outer bearings 2 are arranged in the housing 1, the outer ring 79 of the outer bearing 2 near one axial end of the through-hole 16 is in contact with the stepped portion between the large-diameter hole 69 and the small-diameter hole 67, and the outer ring 79 of the outer bearing 2 near the other axial end of the through-hole 16 is in contact with a pressing portion 36 provided on the housing 1. The pressing portion 36 has the shape of a thick plate and is fixed to the end surface of the other axial end of the housing 1 with a bolt or the like.The pressing portion 36 has a through-hole 37 penetrating it in the thickness direction. The through-hole 37 has a stepped portion.

[0038] A first rotating body 3 includes a main body 19 supported by an inner ring 80 of each outer bearing 2. In this case, the outer peripheral surface of a small-diameter portion 22 of the main body 19 is fixed to the inner rings 80 of the outer bearings 2. In the state where the first rotating body 3 is supported by the outer bearings 2, the inner ring 80 of the outer bearing 2 near one axial end of the through-hole 16 is in contact with the stepped portion between the large-diameter portion 21 and the small-diameter portion 22, and the inner ring 80 of the outer bearing 2 near the other axial end of the through-hole 16 is in contact with an annular pressing portion 72 provided on the first rotating body 3.

[0039] A first sealed space 57 is formed by sealing openings of a cylindrical gap between the housing 1 and the first rotating body 3, such that the opening near one axial end is sealed with a third sealing member 74 having an annular shape, and the opening near the other axial end is sealed with a fourth sealing member 75 having an annular shape. In the second embodiment, the fourth sealing member 75 seals a gap between the inner peripheral surface of a small-diameter hole of a through-hole 37 of the pressing portion 36 and the outer peripheral surface of the first rotating body 3. With this configuration, the outer bearings 2 are arranged in the first sealed space 57.In this case, a gap is formed between the third sealing member 74 and the outer bearing 2 near one axial end of the through hole 16, and a gap is formed between the fourth sealing member 75 and the outer bearing 2 near the other axial end of the through hole 16.

[0040] In this way, the outer bearings 2 are arranged in the first sealed space 57, leaving a first subspace 76 and a second subspace 77, which are near one axial end and the other axial end of the first sealed space 57, respectively. In this case, a downstream end of a first lubrication path 55 communicates with or is connected to the first subspace 76. An upstream end of a second lubrication path 61 communicates with or is connected to the second subspace 77.

[0041] In the lubrication structure of the second embodiment, a lubricant supplied from a lubricator passes through the first lubrication path 55 to flow into the first subspace 76 of the first sealed space 57. The lubricant then passes from the first subspace 76 of the first sealed space 57 through the interior of the outer bearings 2 to flow into the second subspace 77. Subsequently, the lubricant passes from the second subspace 77 of the first sealed space 57 through the second lubrication path 61 to enter a second sealed space 63. In this way, the lubricant is supplied to the inner bearings 4. Thereafter, the lubricant is discharged to the outside of the housing 1 through a discharge path 66.

[0042] Next, a modification of the lubrication structure for a bearing of the second embodiment will be described with reference to Fig. 4. Components denoted by the same reference numerals as in the first embodiment perform the same functions as in the first embodiment, and their descriptions are omitted below. The lubrication structure of the present modification includes a plurality of first lubrication paths 55 and a plurality of second lubrication paths 61.

[0043] As in Fig. As shown in Figure 4, the lubrication structure according to the present modification includes two first lubrication paths 55, 55 and second lubrication paths 61, 61 corresponding to the two first lubrication paths 55, 55. The two first lubrication paths 55, 55 are provided at mutually facing positions with the first rotating body 3 interposed therebetween. The two second lubrication paths 61, 61 are provided at mutually facing positions with the first rotating body 3 interposed therebetween.

[0044] Next, a lubricating structure for a bearing according to a third embodiment of the present invention will be described with reference to Fig. 5. Components denoted by the same reference numerals as in the first embodiment perform the same functions as in the first embodiment, and their descriptions will be omitted below. The lubricating structure according to the third embodiment includes a first sealed space 57 with a different configuration than that of the first embodiment.

[0045] As in Fig. 5, a fifth sealing member 78 having a ring shape is arranged between a housing 1 and a first rotating body 3 so that a gap is formed between the fifth sealing member 78 and an outer bearing 2. Typically, the fifth sealing member 78 is arranged so that a gap is formed between the fifth sealing member 78 and a first bearing 27. As a result, the first sealed space 57 is formed between a first sealing member 58 of the first bearing 27 and the fifth sealing member 78. Specifically, in the third embodiment, the fifth sealing member 78 is arranged between the housing 1 and the first rotating body 3 so that a gap is formed between the fifth sealing member 78 and the sealing member provided on the outer bearing 2. In this way, the outer bearing 2 is arranged adjacent to the first sealed space 57.

[0046] The outer bearing 2 is a bearing that includes an outer ring spacer 31 and an inner ring spacer 34, but can also be a standard ball bearing. In this case, the outer bearing is provided with a sealing element.

[0047] Next, a modification of the lubrication structure for a bearing of the third embodiment will be described with reference to Fig. 6. Components denoted by the same reference numerals as in the first embodiment perform the same functions as in the first embodiment, and their descriptions may be omitted below. The lubrication structure according to the present modification includes a plurality of first lubrication paths 55 and a plurality of second lubrication paths 61.

[0048] As in Fig.As shown in Figure 6, the lubricating structure according to the present modification includes two first lubrication paths 55, 55 and second lubrication paths 61, 61 corresponding to the two first lubrication paths 55, 55, respectively. The two first lubrication paths 55, 55 are provided at mutually facing positions with the first rotating body 3 interposed therebetween. The two second lubrication paths 61, 61 are provided at mutually facing positions with the first rotating body 3 interposed therebetween.

[0049] It should be noted that the present invention is not limited to the above-described embodiments and modifications, and changes and improvements within a range in which the object of the present invention can be achieved are included in the present invention.

[0050] For example, each of the above-described embodiments and modifications may include a larger number of the second lubrication paths 61 than the first lubrication paths 55. EXPLANATION OF REFERENCE SYMBOLS 1 housing 2 external warehouses 3 first rotation body 4 bottom brackets 5 second rotation body 27 first camp 28 second camp 29 Outer ring of the first bearing 30 Outer ring of the second bearing 31 outer ring spacers 32 Inner ring of the first bearing 33 Inner ring of the second bearing 34 inner ring spacers 55 first lubrication path 57 first sealed room 58 first sealing element 59 second sealing element 60 outer through hole 61 second lubrication path 62 inner through hole 63 second sealed room 65 exposed area or surface 66 Drainage path 76 first subspace 77 second subspace QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 8-192447

[0004]

Claims

[1] Lubrication structure for a bearing, the lubrication structure comprising: a housing with a hollow shape; an outer bearing having an outer ring held on an inner peripheral surface of the housing; a first rotating body having a hollow shape and fixed to an inner ring of the outer bearing; an inner bearing having an outer ring held on an inner peripheral surface of the first rotating body; and a second rotating body which is attached to an inner ring of the inner bearing, wherein the housing contains a first lubrication path through which a lubricant flows to be supplied to the inner bearing, wherein the first lubrication path has a downstream end communicating with a first sealed space sealed and formed between the housing and the first rotating body, wherein the first rotating body includes a second lubrication path having an upstream end communicating with the first sealed space, wherein the second lubrication path has a downstream end communicating with a second sealed space sealed and formed between the first rotating body and the second rotating body, wherein the inner bearing is arranged in the second sealed space. [2] A lubricating structure for a bearing according to claim 1, wherein the first rotating body has an exposed surface exposed from the housing, and a discharge path through which the lubricant in the second sealed space is discharged to an outside of the housing has an outlet opening on the exposed surface. [3] A lubricating structure for a bearing according to claim 1 or 2, wherein the outer bearing comprises: a first bearing and a second bearing adjacent to each other; an outer ring spacer connecting an outer ring of the first bearing and an outer ring of the second bearing; and an inner ring spacer connecting an inner ring of the first bearing and an inner ring of the second bearing, a cylindrical gap is formed between the outer ring spacer and the inner ring spacer and has one axial end sealed by a first sealing member and another axial end sealed by a second sealing member, the cylindrical gap sealed by the first sealing member and the second sealing member forms or represents the first sealed space, the downstream end of the first lubrication path communicates with the first sealed space via an outer through hole formed in the outer ring spacer, and the upstream end of the second lubrication path communicates with the first sealed space via an inner through hole formed in the inner ring spacer. [4] A lubricating structure for a bearing according to claim 1 or 2, wherein the outer bearing is arranged in the first sealed space so that a first subspace and a second subspace remain, wherein the first subspace is near one axial end of the first sealed space, the second subspace is near another axial end of the first sealed space, the downstream end of the first lubrication path communicates or is connected to the first subspace, and the upstream end of the second lubrication path communicates or is connected to the second subspace. [5] A lubricating structure for a bearing according to claim 1 or 2, wherein the outer bearing is arranged adjacent to the first sealed space.

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