Cooling structure of bearing device and bearing device with cooling structure

Abstract

The utility model relates to a cooling structure of a bearing device and the bearing device with the cooling structure. A bearing device (J) has a plurality of rolling bearings (1, 1) arranged in the axial direction, and an outer ring gasket (4) and an inner ring gasket (5) respectively interposed between outer rings and inner rings of the rolling bearings (1, 1), and the rolling bearings (1) are lubricated by grease filled in a bearing interior space (S1) between the inner and outer rings. Both axial end portions of the inner ring gasket (5) are provided with blocking walls (33) which extend to the outer diameter side and prevent compressed air (A) supplied from the supply port from flowing into the bearing internal space (S1). The outer diameter end of the barrier wall (33) faces the inner peripheral surface of the outer ring gasket (4) with a radial gap (delta 2) therebetween. A height difference ([Delta] t) is provided between an abutting surface (5a) of the inner ring gasket (5) and the inner ring (3) and an axially outer side surface (33a) of the barrier wall (33), and the height difference ([Delta] t) is recessed further toward the axially inner side of the inner ring gasket (5) than the abutting surface (5a).

Description

TECHNICAL FIELD

[0001] The utility model relates to the cooling structure of bearing device and the bearing device with cooling structure mainly relates to the technology of the grease lubrication of the angular contact ball bearing used in the main shaft of machine tool. BACKGROUND

[0002] In order to ensure the machining accuracy, in the main shaft device of machine tool, the temperature rise of device needs to be inhibited smaller. However, in recent machine tool, in order to improve the machining efficiency, there is the tendency of high speed, and the heat from the bearing supporting the main shaft also rises with the high speed.

[0003] As the method of inhibiting the temperature rise of bearing with the high speed of main shaft device, there is the method of delivering the compressed air for cooling to the bearing, and cooling the shaft and bearing. In particular, in order to prevent the grease in the bearing from being scattered by the compressed air in the grease lubrication, the scheme of setting the barrier wall extending to the outer diameter side at both end portions of the inner ring gasket is proposed (patent document 1).

[0004] [Prior art document]

[0005] [Patent document]

[0006] [Patent document 1] Japanese patent publication No. 6050072 Utility model content

[0007] [Utility model problem to be solved]

[0008] When the shaft and bearing are cooled by using the compressed air, in order to prevent the grease from being scattered, the sealing member and other components must be applied on the bearing. In order to ensure the bearing internal space affecting the filling amount of grease in the bearing, the sealing member is preferably arranged as close to the both ends of the bearing as possible. However, in order to prevent the interference (contact) between the sealing member and the peripheral structure of the bearing, the sealing member is arranged on the inner side of the bearing from the end face of the inner ring and the outer ring of the bearing.

[0009] On the other hand, the barrier wall extending to the outer diameter side is provided at both end portions of the inner ring gasket arranged between the bearings. In order to prevent the interference between the sealing member and the barrier wall of the inner ring gasket, a clear gap needs to be ensured between the sealing member and the barrier wall.

[0010] As the method of applying the pre-press to the bearing, there is the fixed position pre-press and the fixed pressure pre-press. In addition, as the basic combination of bearing, there is the face-to-face combination, the back-to-back combination and the parallel combination, and in the main shaft device of machine tool, most of them are used in the back-to-back combination DB of Figure 15 or the parallel combination DT of Figure 16 .

[0011] In the case where the spindle device is used for position-constant pre-pressing, since the axial positions of the bearing and the liner are fixed, the gap between the seal and the barrier wall of the inner ring liner maintains the initial gap.

[0012] In the case where the spindle device is used for position-constant pre-pressing and parallel combination, as shown in FIG. Figure 17 , a gap a is set between the seal 31 and the inner ring liner 5Z in the initial state. Figure 18 As shown in FIG. Figure 18 , when the bearing 1 generates heat and the inner ring 3 mainly expands, in order to ensure the prescribed pre-pressing amount, the outer ring 2 and the outer ring liner 4 move to the left, i.e., the axial direction. Figure 18 Δa is the outer ring moving amount accompanying the pre-pressing adjustment. At this time, since the seal 31 is fitted to the outer ring 2, the seal 31 also moves together with the outer ring 2. Thus, the gap between the seal 31 and the barrier wall 33B of the inner ring liner 5Z is reduced, and interference can occur.

[0013] As shown in FIG. Figure 19 , even in the case where the spindle device is used for position-constant pre-pressing and back-to-back combination, since the outer ring 2 and the outer ring liner 4 also move in the axial direction as in the parallel combination, the gap between the seal 31 and the barrier wall of the inner ring liner 5Z is reduced, and interference can occur.

[0014] The purpose of the present application is to provide a cooling structure of a bearing device which can maintain the bearing function while obtaining a cooling effect in a bearing device lubricated by lubricating grease, and a bearing device having the cooling structure.

[0015] [Technical Solution for Solving the Problem]

[0016] The cooling structure of the bearing device according to the present application is as follows. The bearing device has a plurality of rolling bearings arranged in the axial direction, and outer ring liners and inner ring liners respectively interposed between the outer rings and the inner rings of the rolling bearings. The rolling bearings are lubricated by lubricating grease filled in the bearing internal spaces between the inner and outer rings.

[0017] In the cooling structure of the bearing device, a supply port is provided on the inner peripheral surface of the outer ring liner, the supply port supplies compressed air for cooling to the outer peripheral surface of the inner ring liner, a discharge port is provided on the outer ring liner, the discharge port discharges the compressed air supplied from the supply port,

[0018] A barrier wall is provided on both axial end portions of the inner ring liner, the barrier wall protrudes to the outer diameter side, and prevents the compressed air supplied from the supply port from flowing into the bearing internal space. The outer diameter end of the barrier wall opposes the inner peripheral surface of the outer ring liner with a radial gap therebetween.

[0019] A difference Δt is provided between the abutment surface of the inner ring liner and the axial outer side surface of the barrier wall, and the difference Δt is recessed further toward the axial inner side of the inner ring liner than the abutment surface.

[0020] In the case where the outer ring has seal members at both axial ends, the "bearing inner space" is a space between the axial inner side surfaces of the two seal members in the axial direction. In the case where there are no seal members, the "bearing inner space" is a space between the axial ends of the inner and outer rings in the axial direction. In the case where there is a seal member at only one axial end of the outer ring, the "bearing inner space" is a space between the axial inner side surface of the seal member and the axial end of the inner and outer rings that does not have a seal member in the axial direction.

[0021] According to this structure, by supplying compressed air for cooling from the supply port provided in the outer ring liner to the outer peripheral surface of the inner ring liner, the compressed air colliding with the inner ring liner takes away heat from the bearing device and the shaft supported by the bearing device. Thus, the bearing device and the shaft are efficiently cooled. The barrier wall is provided at both axial ends of the inner ring liner, and the compressed air is prevented from flowing into the bearing inner space, so that the lubricating grease filled in the bearing inner space can be prevented from being discharged by the compressed air. Thus, a good lubrication state can be maintained.

[0022] A difference Δt is provided between the abutment surface of the inner ring liner and the axial outer side surface of the barrier wall. The difference Δt is recessed further toward the axial inner side of the inner ring liner than the abutment surface. Thus, even in the case where the outer ring and the outer ring liner move in the axial direction due to thermal expansion of the inner ring during operation of the bearing, a gap between the fixing member such as a seal fixed to the outer ring and the barrier wall of the inner ring liner can be ensured. Thus, interference between the fixing member and the barrier wall of the inner ring liner can be prevented in advance.

[0023] The difference Δt can satisfy a relationship of 0.1 mm < Δt < 0.5 mm. In this case, not only the dimensional accuracy of the difference Δt can be easily ensured, but also the production cost can be reduced. When the difference Δt is 0.1 mm or less, it is sometimes difficult to ensure the dimensional accuracy of the inner ring liner processing. When the difference Δt is 0.5 mm or more, the cutting amount of the inner ring liner is large, so that the processing time increases and the production cost increases.

[0024] Also, the inner ring spacer can have two inner ring spacer segments divided by an axial middle portion, and when the inner ring spacer segments are configured such that the outer diameter of the abutment side of each inner ring spacer segment abutting each other is D and the outer diameter of the abutment surface of the inner ring spacer is D', the relationship D ≤ D' is satisfied, and preferably D = D'. In this case, the load from the inner ring on one axial side can be reliably transmitted to the inner ring on the other axial side via the inner ring spacer. Both end surfaces of the spacer are ground at the same time. In the case of D ≠ D', the areas of the left and right ground surfaces of the spacer are different. The side with the larger area is ground less in grinding. Therefore, since the amount of grinding is different between the left and right sides, it is difficult to fine-tune the width dimension.

[0025] In the case of D = D', the grinding range of both end surfaces of the inner ring spacer segment can be made the same, and the amount of grinding in the left and right sides can be made the same, so fine-tuning of the width dimension is easy. Therefore, compared to the case of D < D', it is possible to achieve a reduction in processing time.

[0026] Also, the outer diameter surface of the barrier wall can be tapered such that the amount of protrusion toward the outer diameter side increases as the axial side of the rolling bearing is approached, and the discharge port of the outer ring spacer can be a notch provided on the axial end surface of the outer ring spacer.

[0027] In this case, the compressed air supplied from the supply port flows along the outer peripheral surface of the inner ring spacer to the axial outer side through the space between the inner ring spacer and the outer ring spacer, i.e., the spacer inner space, and is further guided to the outer diameter side along the tapered outer diameter surface of the barrier wall of the inner ring spacer, and is discharged from the notch provided on the axial end surface of the outer ring spacer. Thus, the flow of compressed air in the spacer inner space and the discharge of compressed air from the spacer inner space become smooth. In addition, by causing smooth flow of compressed air in the spacer inner space, the internal pressure of the spacer inner space is made lower than the internal pressure of the bearing inner space, and the inflow of compressed air into the bearing inner space can be suppressed.

[0028] Also, the circumferential positions of the supply port and the notch can be offset from each other. In this case, the compressed air supplied from the supply port to the spacer inner space, when flowing along the outer peripheral surface of the inner ring spacer to the notch, is accompanied by movement in the circumferential direction in addition to movement to the axial outer side, so the time during which the compressed air contacts the inner ring spacer is lengthened, and the effect of cooling the bearing device and the shaft is improved.

[0029] Also, the rolling bearing can have a seal member that seals the inside of the bearing at an axial end of the outer ring, the outer diameter end of the barrier wall can be located on the outer diameter side of the end surface of the inner ring and on the inner diameter side of the end surface of the outer ring, and the axial outer side surface of the barrier wall can be shaped so as to face the seal member with an axial gap therebetween, thereby providing a labyrinth seal effect between the seal member and the barrier wall. Thus, the inflow of compressed air into the inside of the bearing can be further prevented. The "labyrinth seal effect" is an effect of improving the sealing performance of the seal member by forming a curved passage between the barrier wall as a rotating portion and the seal member as a fixed portion.

[0030] Also, when the inner diameter of the seal member is D1 and the outer diameter of the abutting surface of the inner ring liner is D', the relationship D1>D' can be satisfied. The inner diameter D1 refers to the radial dimension of the inner diameter edge of the outer side surface of the seal member. According to this structure, the interference between the seal member and the barrier wall of the inner ring liner can be more reliably prevented.

[0031] The cooling structure of the bearing device of the present application can be applied to a main shaft that supports a machine tool. In this case, since the cooling effect of the main shaft is high, a higher speed rotation can be performed.

[0032] The bearing device of the present application has any one of the above-described cooling structures.

[0033] Any combination of two or more of the claims, or any combination of the features of the claims, is included in the present application. In particular, any combination of two or more of the claims in the claims section is included in the present application. BRIEF DESCRIPTION OF DRAWINGS

[0034] The present application will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely illustrative and should not be used in a limiting sense. The scope of the present application is determined by the appended claims. In the drawings, the same symbols refer to the same or similar parts throughout the several views.

[0035] Figure 1 is a longitudinal sectional view of a bearing device with a cooling structure according to a first embodiment of the present application.

[0036] Figure 2 is a longitudinal sectional view of a bearing device with a cooling structure according to a first embodiment of the present application. Figure 1 is a partial enlarged view of

[0037] Figure 3 is a sectional view of the inner ring liner and the outer ring liner of the bearing device cut in a plane perpendicular to the axial direction.

[0038] Figure 4is an expanded view showing a portion of the outer ring liner of the bearing device.

[0039] Figure 5 is an enlarged sectional view partially showing an initial state of the bearing device.

[0040] Figure 6 is an enlarged sectional view partially showing a pre-press adjustment state of the bearing device.

[0041] Figure 7 is a view showing a manufacturing process of an inner ring liner of a conventional structure.

[0042] Figure 8 is a view showing a manufacturing process of an inner ring liner of the bearing device.

[0043] Figure 9 is an enlarged sectional view showing parameters and the like of the bearing device.

[0044] Figure 10 is a longitudinal sectional view of a bearing device of a second embodiment of the present application having a cooling structure.

[0045] Figure 11 is an expanded view showing a portion of the outer ring liner of the bearing device.

[0046] Figure 12 is a sectional view obtained by cutting the inner ring liner and the outer ring liner of the bearing device of the third embodiment of the present application in a plane perpendicular to the axial direction.

[0047] Figure 13 is a longitudinal sectional view of a bearing device of a fourth embodiment of the present application having a cooling structure.

[0048] Figure 14 is a longitudinal sectional view showing a state in which the bearing device of any of the embodiments is assembled into a spindle device of a machine tool.

[0049] Figure 15 is a longitudinal sectional view of a bearing device for back-to-back combination of a conventional structure.

[0050] Figure 16 is a longitudinal sectional view of a bearing device for parallel combination of a conventional structure.

[0051] Figure 17 is an enlarged sectional view partially showing an initial state of the bearing device.

[0052] Figure 18 is an enlarged sectional view partially showing a pre-press adjustment state of the bearing device.

[0053] Figure 19 is a longitudinal sectional view of a bearing device for constant-pressure pre-press and back-to-back combination of a conventional structure. Detailed Implementation

[0054] [First Implementation Method]

[0055] and Figures 1-9 The cooling structure of the bearing device according to an embodiment of this utility model will be described together. The bearing device is used, for example, to support the spindle of a machine tool described later.

[0056] like Figure 1 As shown, the bearing assembly J has a plurality of rolling bearings 1, 1 arranged axially, and outer ring gaskets 4 and inner ring gaskets 5 respectively located between the outer rings 2, 2 and the inner rings 3, 3 of these rolling bearings 1, 1. Figure 3 On the housing 6 shown, via Figure 1 The rolling bearings 1, 1, outer ring gasket 4, and inner ring gasket 5 rotatably support the main shaft 7, which serves as the rotating body. Figure 3 ). Figure 3 L1 is the rotation direction of spindle 7.

[0057] In the following description, the direction of the bearing center axis AX is referred to as the "axial direction", the direction perpendicular to the bearing center axis AX is referred to as the "radial direction", and the circumferential direction around the bearing center axis AX is referred to as the "circumferential direction". In addition, the side facing the bearing center axis AX is referred to as the "inner diameter side", and the side away from the bearing center axis AX is referred to as the "outer diameter side".

[0058] <Rolling bearings>

[0059] Each rolling bearing 1 is an angular contact ball bearing. These angular contact ball bearings are arranged in parallel, for example, and are used for constant pressure preload. In this specification, the rolling bearing 1 is sometimes simply referred to as a "bearing". The rolling bearing 1 has an inner ring 3, an outer ring 2, a plurality of rolling elements 8, a retainer 9, and sealing components 31, 31. The plurality of rolling elements 8 are located between the raceway surfaces of the inner and outer rings 3, 2. The plurality of rolling elements 8 are held by the retainer 9 in a circumferentially spaced arrangement. The rolling bearing 1 is lubricated by grease filling the bearing internal space S1 between the inner and outer rings 3, 2. The outer ring 2 of each rolling bearing 1 is fixed in the housing 6, and the inner ring 3 is fitted and fixed on the outer circumferential surface of the main shaft 7.

[0060] The inner and outer rings 3 and 2 are made of bearing steel or the like. Each rolling element 8 is a steel ball made of bearing steel or a ceramic ball made of ceramic. The inner circumferential surfaces on both sides of the outer ring 2 serve as guide surfaces to guide the outer circumferential surface of the retainer 9. The axial ends of the inner and outer rings 3 and 2 are sealed by sealing components 31, 31, which are non-contact seals. Each sealing component 31 includes a mandrel and an elastic body covering the mandrel. The non-contact seals are used to cope with high-speed operation.

[0061] An outer ring seal groove is formed on each of the axial end portions of the inner peripheral surface of the outer ring, and a seal member 31 is fitted and fixed to each of the outer ring seal grooves. The seal member 31 on the bias side of the contact angle is disposed so that the inner diameter side front end portion is spaced apart from the inner ring secondary bore by a predetermined radial gap. The seal member 31 on the reverse bias side of the contact angle is disposed so that the inner diameter side front end portion is spaced apart from the inner ring outer peripheral surface of the inner ring seal groove by a predetermined labyrinth gap. The predetermined radial gap and the predetermined labyrinth gap are gaps arbitrarily determined by design, etc., and are determined by, for example, either or both of trial and simulation.

[0062] <Concerning the Cooling Structure>

[0063] As shown in Figure 2 , a radial gap δ1 is provided between the inner peripheral surface of the outer ring liner 4 and the outer peripheral surface of the inner ring liner 5. A supply port 10 for supplying compressed air for cooling to the outer peripheral surface of the inner ring liner 5 is provided on the inner peripheral surface of the outer ring liner 4. In this example, as shown in Figure 3 , the number of supply ports 10 is, for example, three, and each supply port 10 is disposed at equal intervals in the circumferential direction.

[0064] As shown in Figure 2 and Figure 3 , an annular introduction groove 11 for introducing compressed air A is provided on the outer peripheral surface of the outer ring liner 4. The introduction groove 11 is provided at the axial middle portion of the outer peripheral surface of the outer ring liner 4 and communicates with each supply port 10 via a connection hole 11a. Compressed air A is supplied to the introduction groove 11 from a not-shown compressed air supply device provided outside the bearing device J, through a compressed air introduction hole 46 provided in the housing 6.

[0065] <Concerning the Obstructing Wall, etc.>

[0066] As shown in Figure 1 , the axial end portions of the inner ring liner 5 are formed as obstructing walls 33 that project outward in the radial direction. The obstructing walls 33 prevent the compressed air A supplied from the supply ports 10 from flowing into the bearing inner space S1. The obstructing walls 33 are tapered so that the amount of projection outward in the radial direction increases as the axial position of the rolling bearing 1 is approached. A cutout 34 is provided on the axial end surface of the outer ring liner 4, and this cutout 34 serves as a discharge port for the compressed air A supplied from the supply ports 10.

[0067] The cutout 34 has, for example, a rectangular cross-sectional shape as shown in Figure 4 , and is disposed so as to abut against the outer ring liner 4 of Figure 2 , with the outer ring 2 of the rolling bearing 1 disposed therebetween. Thus, the cutout 34 is formed in an open shape that communicates the liner inner space S2 between the outer ring liner 4 and the inner ring liner 5 with the outside of the bearing device J. As shown in Figure 4 , the circumferential positions of the supply ports 10 and the cutout 34 are the same. However, the circumferential positions are not limited to this.

[0068] In this structure, such as Figure 2 As shown, in order to assemble the outer ring gasket 4 (in order to prevent interference between the inner circumference of the outer ring gasket 4 and the obstruction wall 33), the inner ring gasket 5 has, for example, two inner ring gasket segments 5A, 5A, which are divided into two parts by the axial middle portion.

[0069] The outer diameter end of the obstruction wall 33 is opposite to the inner circumferential surface of the outer ring gasket 4 with a specified radial clearance δ2. For example... Figure 5 As shown, a height difference Δt is provided between the mating surface 5a of the inner ring gasket 5 and the inner ring 3 and the axial outer surface 33a of the obstruction wall 33. The height difference Δt is recessed further into the axial inner side A1 of the inner ring gasket 5 than the mating surface 5a. In other words, the obstruction wall 33 on the mating side of the inner ring gasket 5 (the part that is further outward than the outer diameter of the inner ring that does not mate with the inner ring 3) is positioned in a stepped shape that moves towards the axial inner side A1 of the inner ring gasket 5.

[0070] By setting the inner ring gasket 5 in such a stepped shape, it is possible to ensure that the axial clearance b between the sealing member 31 and the obstruction wall 33 of the inner ring gasket 5 is large in the initial state. The aforementioned axial clearance b in the initial state is the value (a+Δt) obtained by adding the height difference Δt to the axial length a between the axial outer side surface 33a of the sealing member 31 and the end face of the inner ring in the initial state of the bearing assembly J (the state before the bearing is running).

[0071] The outer diameter end 33D of the obstruction wall 33 is located on the outer diameter side of the end face of the inner ring 3 and on the inner diameter side of the end face of the outer ring 2, with the axial outer surface 33a of the obstruction wall 33 facing the sealing member 31 across the axial clearance b. Thus, a labyrinth seal portion 35 with a labyrinth seal effect is constructed by the sealing member 31 and the obstruction wall 33, and the labyrinth seal portion 35 separates the bearing internal space S1 from the gasket internal space S2.

[0072] In the Figure 6 Under the pre-pressure adjustment state caused by heat generation, if the movement of the outer ring accompanying the pre-pressure adjustment is set as Δa, then the axial clearance b' between the sealing component 31 and the inner ring gasket 5 becomes the axial clearance b from the initial state. Figure 5 The value is obtained by subtracting the outer ring movement Δa. Therefore, in bearings used for constant pressure preload, even if the outer ring 2 and the sealing member 31 fitted to the outer ring 2 move axially for preload adjustment, the axial clearance b' between the sealing member 31 and the obstruction wall 33 of the inner ring gasket 5 can be ensured, preventing interference between the sealing member 31 and the obstruction wall 33 of the inner ring gasket 5. Furthermore, Figure 6 D2 represents the outer diameter of the inner ring.

[0073] On the other hand, the manufacturing process of the inner ring gasket 5 generally involves "turning → heat treatment → grinding". In particular, the "grinding process," which determines the width of the inner ring gasket 5, is crucial. Suppose that during the "heat treatment process," the inner ring gasket 5 experiences significant warping on the obstruction wall 33 extending towards the outer diameter side. Figure 7 In the existing shapes shown in (a) and (b), due to the grinding range Ga and grinding amount Gb in the "grinding process" Figure 7 (b) becomes larger, making it difficult to adjust the width W5 of the inner ring gasket. Additionally, Figure 7 The solid line in (a) represents the warped state of the barrier wall 33B, while the double-dotted line in the figure represents the original state of the barrier wall 33B.

[0074] like Figure 8 As shown in (a) and (b), when the obstruction wall 33 is set in a stepped shape, the grinding range Ga and grinding amount in the "grinding process" can be reduced to a smaller size compared to the existing shape, and the adjustment of the width dimension W5 of the inner ring liner 5 becomes easier.

[0075] <Parameters>

[0076] like Figure 9 As shown, the height difference Δt satisfies the relationship 0.1mm < Δt < 0.5mm. Under these conditions, not only can the dimensional accuracy of the height difference Δt be easily ensured, but manufacturing costs can also be reduced. When the height difference Δt is below 0.1mm, it is sometimes difficult to ensure the dimensional accuracy of the inner ring gasket 5. When the height difference Δt is above 0.5mm, the cutting amount of the inner ring gasket 5 is large, increasing machining time and manufacturing costs.

[0077] Alternatively, it can be configured with inner ring liner segmentation bodies 5A and 5A ( Figure 1 The condition is as follows: when the outer diameter of the mating side of each inner ring gasket segment 5A is D, and the outer diameter of the mating surface 5a between the inner ring gasket 5 and the inner ring 3 is D', the relationship D ≤ D' is satisfied, preferably D = D'. In this case, it is possible to... Figure 1 The load on one axial inner ring 3 is reliably transferred to the other axial inner ring 3 via the inner ring shim 5. Simultaneously, both ends of the shim are ground. When D≠D', the areas of the left and right grinding surfaces of the shim are different. The side with the larger area receives less cutting during grinding. Therefore, due to the difference in cutting amount between the left and right sides during grinding, it is difficult to make fine adjustments to the width dimension. Figure 9 As shown, when D = D', the grinding range of both ends of the inner ring liner divider 5A can be made the same, and the amount of material cut during grinding can be the same on both sides, thus facilitating fine-tuning of the width dimension. Therefore, compared to the case where D < D', machining time can be reduced.

[0078] Alternatively, if the inner diameter of the outer surface of the sealing component 31 is D1 and the outer diameter of the mating surface 5a of the inner ring gasket 5 and the inner ring 3 is D', then the relationship D1 > D' is satisfied. In this case, interference between the sealing component 31 and the obstruction wall 33 of the inner ring gasket 5 can be prevented more reliably.

[0079] <Effects>

[0080] Figure 1 During operation, the bearing assembly J receives cooling compressed air A from a compressed air supply device located outside the bearing assembly J. This compressed air is supplied from the supply port 10 of the outer ring gasket 4 to the outer peripheral surface of the inner ring gasket 5. After colliding with the inner ring gasket 5, the compressed air A flows axially to both sides along the outer peripheral surface of the inner ring gasket 5, and is then guided to the outer diameter side along the conical outer diameter surface of the obstruction wall 33 of the inner ring gasket 5, and discharged from the cutout 34 of the outer ring gasket 5. By using the obstruction wall 33 to guide the compressed air A to the outer diameter side, the flow of compressed air A in the gasket interior space S2 and the discharge of compressed air A from the gasket interior space S2 become smooth. During the passage of compressed air A through the gasket interior space S2, it dissipates heat from the bearing assembly J and the spindle 7 supported by the bearing assembly J. As a result, the bearing assembly J and the spindle 7 are cooled efficiently.

[0081] By providing obstruction walls 33 at both axial ends of the inner ring gasket 5, compressed air A is prevented from flowing into the bearing internal space S1. Furthermore, the bearing internal space S1 and the gasket internal space S2 are sealed by a labyrinth seal 35. Figure 5 The gasket is separated from the bearing internal space S1, thus more effectively preventing compressed air A from flowing into the bearing internal space S1. Furthermore, since compressed air A flows smoothly within the gasket internal space S2, the internal pressure of the gasket internal space S2 is lower than that of the bearing internal space S1, making it difficult for compressed air A to flow into the bearing internal space S1. Therefore, the inflow of compressed air A into the bearing internal space S1 is effectively suppressed, preventing the grease filling the bearing internal space S1 from being discharged by compressed air A. Thus, good lubrication is maintained.

[0082] like Figure 5 As shown, a height difference Δt is provided between the mating surface 5a of the inner ring gasket 5 and the inner ring 3 and the axial outer surface 33a of the obstruction wall 33. This height difference Δt is recessed further into the axial inner side A1 of the inner ring gasket 5 than the mating surface 5a. Therefore, as Figure 6 As shown, even when the outer ring 2 and outer ring gasket 4 move axially due to the thermal expansion of the inner ring 3 during bearing operation, the axial clearance b' between the sealing member 31 fixed on the outer ring 2 and the obstruction wall 33 of the inner ring gasket 5 can be ensured. Therefore, interference between the sealing member 31 and the obstruction wall of the inner ring gasket 5 can be prevented, maintaining bearing function.

[0083] [Concerning Other Embodiments]

[0084] In the following description, the same reference numerals are applied to portions corresponding to matters previously described in each embodiment, and repeated description is omitted. In the case of describing only a part of the structure, unless specifically described, other parts of the structure are the same as the previously described embodiment. The same structure functions to achieve the same effects. Not only the portions to be specifically described in each embodiment are combined, but also the embodiments are partially combined with each other, particularly if the combination does not cause a problem.

[0085] [Second Embodiment: Phasing of Supply Port and Cutout]

[0086] As shown in Figs. 1 and 2, the supply port 10 and the cutout 34 can be arranged so as to be mutually offset in the circumferential direction. When the circumferential positions of the supply port 10 and the cutout 34 are mutually offset, as shown in Figs. 3 and 4, the compressed air A supplied from the supply port 10 to the inner space S2 of the pad flows along the outer peripheral surface of the inner ring pad 5 to the cutout 34, and in addition to moving to the axial outer side, also moves in the circumferential direction, so the time during which the compressed air A contacts the inner ring pad 5 is lengthened, and the effect of cooling the bearing device J and the main shaft 7 is improved. Figure 10 Figure 11 As shown in Figs. 1 and 2, the supply port 10 and the cutout 34 can be arranged so as to be mutually offset in the circumferential direction. When the circumferential positions of the supply port 10 and the cutout 34 are mutually offset, as shown in Figs. 3 and 4, the compressed air A supplied from the supply port 10 to the inner space S2 of the pad flows along the outer peripheral surface of the inner ring pad 5 to the cutout 34, and in addition to moving to the axial outer side, also moves in the circumferential direction, so the time during which the compressed air A contacts the inner ring pad 5 is lengthened, and the effect of cooling the bearing device J and the main shaft 7 is improved. Figure 10

[0087] [Third Embodiment: Inclination of Supply Port]

[0088] In the case of a shaft that is rotated in a constant direction, such as the main shaft 7 of a machine tool, as shown in Figs. 5 and 6, the air discharge direction of each supply port 10 can be inclined toward the front of the rotation direction L1 of the inner ring 3 ( Figure 12 Figure 1 ) and the main shaft 7. Each supply port 10 is linear, and is located at a position offset (offset amount OS) from an arbitrary radial line L2 of a cross section perpendicular to the shaft center of the outer ring pad 4 to a direction orthogonal to the radial line L2. In this way, if the air discharge direction of each supply port 10 is inclined, when the discharged compressed air A hits the outer peripheral surface of the inner ring pad 5 and flows along the outer peripheral surface to the cutout 34, in addition to moving to the axial outer side, also movement in the circumferential direction is promoted, so the time during which the compressed air A contacts the inner ring pad 5 is lengthened, and the effect of cooling the bearing device J and the main shaft 7 is improved.

[0089] [Fourth Embodiment: Back-to-Back Combination]

[0090] As shown in Figs. 7 and 8, the angular contact ball bearings 1, 1 can be combined back to back, and used for position determination and pre-pressing. Figure 13

[0091] The rolling bearing can also be combined side by side or back to back, and used for position determination and pre-pressing. ​​​​​

[0092] [Examples of applications in machine tool spindle systems]

[0093] like Figure 14 As shown, in the bearing assembly J, the outer rings 2 and 2 of rolling bearings 1 and 1, and the outer ring gasket 4 are fitted with the inner circumferential surface of the housing 6, while the inner rings 3 and 3 of rolling bearings 1 and 1, and the inner ring gasket 5 are fitted with the outer circumferential surface of the machine tool spindle 7. For example, the outer ring 2 and the outer ring gasket 4 form a clearance fit with respect to the housing 6, and the inner ring 3 and the inner ring gasket 5 form a tight fit with respect to the shaft 7. The outer ring 3 of the rolling bearing 1 on one side (the right side of the figure) is axially positioned by the height difference portion 6a of the housing 6, and the inner ring 3 of the rolling bearing 1 is axially positioned by the positioning gasket 41. Furthermore, by pressing the outer ring pressure foot 43 and the inner ring pressure foot 42 onto the outer ring 2 and the inner ring 3 of the rolling bearing 1 on the other side (the left side of the figure), the bearing assembly J is fixed to the housing 6.

[0094] A compressed air inlet hole 46 is provided on the housing 6 and the outer ring pressure foot 43. The compressed air inlet hole 46 introduces cooling compressed air A from the compressed air supply device 45 into the bearing device J. The compressed air inlet hole 46 communicates with the inlet groove 11 provided on the outer peripheral surface of the outer ring gasket 4. An exhaust hole 47 is provided on the housing 6 and the outer ring pressure foot 43. The exhaust hole 47 communicates with the cutout 34 of the outer ring gasket 4 via the connecting hole 48.

[0095] As described above, the cooling structure of the bearing assembly J provides excellent cooling for both the bearing assembly J and the spindle 7, enabling the spindle assembly to operate in a high-speed range. Therefore, the bearing assembly J can be used to support the spindle of a machine tool.

[0096] The bearing assembly J can also be used for purposes other than supporting the spindle of a machine tool.

[0097] Tapered roller bearings can also be used as rolling bearings.

[0098] As described above, preferred embodiments have been illustrated with reference to the accompanying drawings. However, various additions, modifications, and deletions can be made without departing from the spirit of this invention. Therefore, such modifications are also included within the scope of this invention.

[0099] [Symbol Explanation]

[0100] 1…rolling bearings

[0101] 2…outer ring

[0102] 3…Inner circle

[0103] 4…Outer ring gasket

[0104] 5…Inner ring gasket

[0105] 5a … mating surface with inner ring

[0106] 6 … housing

[0107] 7 … main shaft

[0108] 10 … supply port

[0109] 31 … sealing member

[0110] 33 … barrier wall

[0111] 33a … axially outer side surface

[0112] 34 … cutout

[0113] J … bearing device

[0114] S1 … bearing inner space

[0115] S2 … gasket inner space

Claims

1. A cooling structure of a bearing device having a plurality of rolling bearings arranged in an axial direction, and outer ring spacers and inner ring spacers respectively interposed between outer rings and between inner rings of the rolling bearings, the rolling bearings being lubricated by grease filled in a bearing inner space between the outer rings and the inner rings, characterized in that, the cooling structure of the bearing device is provided with a supply port on an inner peripheral surface of the outer ring spacer, the supply port supplying compressed air for cooling to an outer peripheral surface of the inner ring spacer, a discharge port is provided on the outer ring spacer, the discharge port discharging the compressed air supplied from the supply port, a barrier wall is provided on both axial end portions of the inner ring spacer, the barrier wall extending to an outer diameter side, the barrier wall preventing the compressed air supplied from the supply port from flowing into the bearing inner space, an outer diameter end of the barrier wall is opposed to the inner peripheral surface of the outer ring spacer with a radial gap therebetween, a difference in height Δt is provided between an abutment surface of the inner ring spacer and an axial outer side surface of the barrier wall, the difference in height Δt being recessed more to an axial inner side of the inner ring spacer than the abutment surface. The difference in height Δt satisfies a relationship of 0.1 mm < Δt < 0.5 mm. The inner ring spacer has two inner ring spacer segments divided at an axial middle portion, when the inner ring spacer segments are provided such that an outer diameter of an abutment side of each of the inner ring spacer segments abutting each other is D, and an outer diameter of the abutment surface of the inner ring spacer is D', a relationship of D ≤ D' is satisfied. An outer diameter surface of the barrier wall is tapered such that an amount of extension to the outer diameter side is greater on a side closer to the rolling bearing in the axial direction, and the discharge port of the outer ring spacer is a notch provided on an axial end surface of the outer ring spacer.

2. The cooling structure of a bearing device according to claim 1, characterized by, The supply port and the notch are each misaligned in a circumferential direction with each other.

3. The cooling structure of a bearing device according to claim 2, characterized by The rolling bearing has a seal member sealing the bearing inner space at an axial end of the outer ring, an outer diameter end of the barrier wall is located on an outer diameter side of an outer diameter side end of an end surface of the inner ring, and on an inner diameter side of an inner diameter side end of an end surface of the outer ring, the axial outer side surface of the barrier wall is opposed to the seal member with an axial gap therebetween, and the seal member and the barrier wall have a labyrinth seal effect.

4. The cooling structure of a bearing device according to claim 3, characterized by 7. The cooling structure of the bearing device according to claim 6, wherein when an inner diameter of the seal member is Dl, and an outer diameter of the abutment surface of the inner ring spacer is D', a relationship of Dl > D' is satisfied.

5. The cooling structure of a bearing device according to claim 4, characterized by It is used for supporting a main shaft of a machine tool.

6. The cooling structure of a bearing device according to claim 1 or 2, characterized by, It has the cooling structure of the bearing device according to any one of claims 1 to 5. ​ 8. The cooling structure of a bearing device according to claim 1 or 2, characterized by, ​ 9. A bearing device characterized by, ​

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