Rotation support device, and support mechanism position adjustment mechanism for shaft support device

Abstract

A support mechanism (30) that rotatably supports both axial-direction ends of a screw shaft (21) is provided with a bearing unit (41) having a moving-side bearing housing (51) and a pair of angular contact ball bearings (33), a support base (43), and a housing position adjustment mechanism (44) disposed between the bearing unit (41) and the support base (43). The housing position adjustment mechanism (44) is provided with: a support-base-side member (61) provided on the support-base (43) side; a bearing-housing-side member (62) that is provided on the bearing-housing (51) side and is capable of moving relative to the support-base-side member (61) in the axial direction; a partition member (83) that is disposed within a space (66) formed between the support-base-side member (61) and the bearing-housing-side member (62), the partition member (83) dividing the space (66) in the axial direction into a first space (66A) and a second space (66B); a plurality of disc springs (70) and a first working fluid (80) that are accommodated in a compressed state in the first space (66A); and a foam member (90) and a second working fluid (81) that are accommodated in a compressed state in the second space (66B). This makes it possible to continuously and stably maintain axial support rigidity even if the axial length of a rotating shaft changes due to the influence of heat.

Description

Rotation support device and support mechanism position adjustment mechanism for shaft support device

[0001] The present invention relates to a rotation support device that supports a rotation shaft such as a ball screw feed device or a spindle device, and to a support mechanism position adjustment mechanism for a shaft support device that supports a shaft.

[0002] Ball screw feed devices require high axial rigidity to maintain the feed accuracy of the screw shaft. Conventionally, a common method for providing rigidity to the screw shaft of a ball screw device is to combine and preload multiple angular bearings, place them at one or both ends of the screw shaft, and support the screw shaft in the axial direction. In addition, when thermal expansion of the screw shaft is taken into consideration, a method is used in which axial tension is applied to the screw shaft in advance to elongate it by a predetermined amount. Patent Document 1 describes a method in which tension is applied to the feed screw (screw shaft) in advance by adjusting the axial dimension of a spacer, and further includes a pretensioning mechanism that uses a disc spring or fluid pressure to move the bearing axially and apply tension to the feed screw when the feed screw elongates beyond the pretension due to temperature rise.

[0003] Japanese Utility Model Registration No. 2573982

[0004] However, excessive loads, such as pretension or pretension, applied to the feed screw can place a heavy load on the bearing, potentially damaging it. For this reason, a disc spring or an externally supplied fluid, as seen in the pretension mechanism described in Patent Document 1, is typically used to prevent excessive axial loads from being applied to the bearing. However, disc springs, as seen in the pretension mechanism described in Patent Document 1, weaken the load as the shaft elongates, and can only accommodate a temperature rise of 3 to 4 degrees. In machining centers, ball screws often experience temperature rises of more than 4 degrees, which prevents the disc springs from applying sufficient load, resulting in a decrease in axial support rigidity. Furthermore, hydraulic systems that apply loads hydraulically by supplying fluid from an external source require external devices such as a hydraulic pump, increase the size of the ball screw feed device, and result in increased costs and additional energy consumption. Furthermore, these issues exist not only in ball screw feed devices but also in rotation support devices, such as spindle devices, in which both axial ends of a rotating shaft are rotatably supported by a pair of support mechanisms.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a rotation support device and a support mechanism position adjustment mechanism for a shaft support device that can continuously and stably maintain axial support rigidity even if the axial length of the rotating shaft changes due to the effects of heat.

[0006] The above object of the present invention is achieved by the following configuration: [1] A rotary support device comprising a rotating shaft and a pair of support mechanisms rotatably supporting both axial ends of the rotating shaft, one of the pair of support mechanisms comprising: a bearing unit comprising a bearing housing and a bearing that rotatably supports the rotating shaft relative to the bearing housing and is capable of supporting an axial load, a support base through which the rotating shaft passes or is arranged around the rotating shaft, and a housing position adjustment mechanism arranged between the bearing unit and the support base, wherein the housing position adjustment mechanism comprises: a support base side member provided on the support base side and through which the rotating shaft passes or is arranged around the rotating shaft, a bearing housing side member provided on the bearing housing side and through which the rotating shaft passes or is arranged around the rotating shaft and is movable axially relative to the support base side member, a partition member arranged in an accommodation space formed between the support base side member and the bearing housing side member and dividing the accommodation space into a first space and a second space in the axial direction, and a first pressure generating means accommodated in a compressed state in the first space. a second pressure generating means accommodated in the second space in a compressed state, wherein at least one of the first pressure generating means and the second pressure generating means comprises a foam member having a foam core layer, and a working fluid filled in the first space or the second space other than the foam member.[2] A support mechanism position adjustment mechanism for a shaft support device including a shaft and a pair of support mechanisms provided at both axial ends of the shaft to support the shaft, the support mechanism position adjustment mechanism for the shaft support device being provided on one of the pair of support mechanisms, wherein one of the pair of support mechanisms has a support through which the shaft passes or is arranged around the shaft, the support mechanism comprising: a first member provided on one of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis; a second member provided on the other of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis, movable axially relative to the first member, and which forms an accommodation space between itself and the first member; a partition member provided in the accommodation space, which divides the accommodation space into a first space and a second space in the axial direction; a first pressure generating means accommodated in the first space in a compressed state; and a second pressure generating means accommodated in the second space in a compressed state. A support mechanism position adjustment mechanism for a shaft support device, wherein at least one of the first pressure generating means and the second pressure generating means comprises a foam member having a foam core layer, and at least one of a solid skin layer and a cover member covering the periphery of the foam core layer, and a working fluid filled in the first space or the second space other than the foam member.

[0007] According to the rotation support device of the present invention, the axial support rigidity can be continuously and stably maintained even if the axial length of the rotating shaft changes due to the influence of heat. Furthermore, the two types of pressure generating means housed in the housing space can impart the support rigidity and damping characteristics required for the rotation support device.

[0008] Furthermore, with the support mechanism position adjustment mechanism for a shaft support device of the present invention, it is possible to continuously and stably maintain axial support rigidity even if the axial length of the shaft changes due to the influence of heat. Furthermore, the two types of pressure generating means housed in the housing space can impart the support rigidity and damping characteristics required for the shaft support device.

[0009] 1 is a cross-sectional view of a table feed system of a machine tool to which a ball screw feed device according to a first embodiment of the present invention is applied. FIG. 2 is an enlarged cross-sectional view of a support mechanism equipped with the housing position adjustment mechanism shown in FIG. 1. FIG. 3 is a view taken along an arrow A in FIG. 2. FIG. 4 is a cross-sectional view showing an example of a foam member. FIG. 5 is a diagram schematically showing a process for manufacturing a foam member by foam injection molding. FIG. 6 is a side view showing one modified example of a foam member. (a) and (b) are cross-sectional views showing metal foam members according to first and second modified examples of the first embodiment. FIG. 7 is a cross-sectional view showing a foam member according to a third modified example of the first embodiment. (a) is a side view showing a foam member according to a fourth modified example of the first embodiment, and (b) is a cross-sectional view taken along line IX-IX of (a) of (b). (a) to (d) are cross-sectional views of accommodation spaces in which foam members according to fifth to eighth modified examples of the first embodiment are disposed. FIG. 7 corresponds to FIG. 2 of a ball screw feed device according to a modified example of the first embodiment. FIG. 8 corresponds to FIG. 2 of a ball screw feed device according to another modified example of the first embodiment. FIG. 9 corresponds to FIG. 2 of a ball screw feed device according to yet another modified example of the first embodiment. FIG. 10 corresponds to FIG. 2 of a ball screw feed device according to a second modified example of the present invention. 14A and 14B are enlarged cross-sectional views of a portion XV in FIG. 14A. (a) to (c) are enlarged cross-sectional views of a main portion showing an example in which a wear-resistant member is applied to the seal groove of a ball screw feed device according to a modified example of the second embodiment. (a) to (d) are cross-sectional views showing modified examples of the partition member in the second embodiment. (a) to (d) are cross-sectional views showing modified examples of the partition member in the second embodiment. (b) is a view corresponding to FIG. 2 of a ball screw feed device according to a third embodiment of the present invention. (c) is a view corresponding to FIG. 2 of a ball screw feed device according to a fourth embodiment of the present invention. (d) is a view corresponding to FIG. 2 of a modified example of a bearing unit in which a pair of angular contact ball bearings are combined back to back in the first to fourth embodiments. (e) is a view corresponding to FIG. 2 of another modified example of a bearing unit in which a pair of angular contact ball bearings are combined in parallel in the first to fourth embodiments. (a) is a schematic side view showing a first example in which a housing position adjustment mechanism is formed by a plurality of accommodation spaces, and (b) is a schematic side view showing a second example in which a housing position adjustment mechanism is formed by a plurality of accommodation spaces. (a) is a schematic side view showing a third example in which the housing position adjustment mechanism is composed of multiple storage spaces, and (b) is a schematic side view showing a fourth example in which the housing position adjustment mechanism is composed of multiple storage spaces.29 is a schematic side view showing a fifth example in which a housing position adjustment mechanism is configured by a plurality of accommodation spaces. It is a cross-sectional view taken along line XXV-XXV in FIG. 23(a). It is a view corresponding to FIG. 2 of a ball screw feed device according to a fifth embodiment of the present invention. It is a view corresponding to FIG. 2 of a ball screw feed device according to a first modified example of the fifth embodiment. It is a view corresponding to FIG. 2 of a ball screw feed device according to a second modified example of the fifth embodiment. It is a view corresponding to FIG. 2 of a ball screw feed device according to a third modified example of the fifth embodiment. It is an enlarged view of a portion XXX in FIG. 29. It is a view corresponding to FIG. 2 of a ball screw feed device according to a fourth modified example of the fifth embodiment. It is a view corresponding to FIG. 2 of a ball screw feed device according to a fifth modified example of the fifth embodiment. It is a view corresponding to FIG. 2 of a ball screw feed device according to a sixth embodiment of the present invention. It is a view corresponding to FIG. 2 for explaining a modification of the first pressure generating means and the second pressure generating means in the ball screw feed device of the first embodiment. It is a view corresponding to FIG. 2 for explaining another modification of the first pressure generating means and the second pressure generating means in the ball screw feed device of the first embodiment. 37A and 37B are diagrams corresponding to FIG. 2 for explaining modified examples of the first pressure generating means and the second pressure generating means for the ball screw feed device of the sixth embodiment. (a) is an enlarged cross-sectional view corresponding to FIG. 2 in a phase where an oil supply passage formed in a bearing housing side member is provided to fill the accommodating space with working fluid, and (b) is a cross-sectional view showing a modified example of the stopper bolt of (a). (a) is a cross-sectional view of a stopper plug used in place of the stopper bolt of FIG. 37A, (b) is a cross-sectional view showing an example in which the stopper plug of (a) is combined with a disk-shaped member, (c) is a cross-sectional view showing a modified example of the disk-shaped member of (b), and (d) is a cross-sectional view showing another modified example of the disk-shaped member of (b). (b) is a cross-sectional view of a table feed system of a machine tool to which a ball screw feed device according to a modified example of the present invention is applied. (c) is a cross-sectional view showing a first example of a housing position adjustment mechanism in which a support base is disposed on the axial end side of a bearing unit. (d) is a cross-sectional view showing a second example of a housing position adjustment mechanism in which a support base is disposed on the axial end side of a bearing unit. FIG. 10 is a cross-sectional view showing a third example of a housing position adjustment mechanism in which a support base is disposed on the axial end side of a bearing unit.Fig. 46 is a cross-sectional view showing a fourth example of a housing position adjustment mechanism in which a support base is disposed on the axial end side with respect to a bearing unit. Fig. 47 is a cross-sectional view showing a rotation support device according to the present invention. Fig. 48 is a cross-sectional view showing another rotation support device according to the present invention. Fig. 49 is a cross-sectional view showing a shaft support device to which a support mechanism position adjustment mechanism according to the present invention is applied. Fig. 49 is an enlarged view of part XLVII of Fig. 46.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a ball screw feed device, which is an example of a rotation support device or a shaft support device according to the present invention, will be described in detail with reference to the drawings.

[0011] (First Embodiment) Fig. 1 shows a table feed system of a machine tool to which a ball screw feed device of the first embodiment is applied. With reference to Figs. 1 to 3, the axial direction of a screw shaft 21 of a ball screw feed device 20 (the left-right direction in Fig. 1) is defined as the X direction, the direction parallel to the mounting surface 1a of a base 1 and perpendicular to the axial direction of the screw shaft 21 (the direction perpendicular to the plane of the paper in Fig. 1) is defined as the Y direction, and the direction perpendicular to the mounting surface 1a of the base 1 (the up-down direction in Fig. 1) is defined as the Z direction. In Fig. 2 and corresponding figures, dotted lines indicate bolt fastening locations.

[0012] The table feed system 10 includes a moving table 11 fixed to a nut 23 of a ball screw feed device 20. The moving table 11 is configured to be movable in the X direction by driving a screw shaft 21 of the ball screw feed device 20 with a drive motor 12. The moving table 11 is provided with a pair of linear guides 13 (only one of which is shown in FIG. 1 ) on both sides of the ball screw feed device 20 in the Y direction. Each linear guide 13 includes a guide rail 15 disposed on the base 1 via a rail mounting base 14 in parallel to the screw shaft 21, and two sliders 16 fixed to the underside of the moving table 11 and mounted across the guide rails 15. When the drive motor 12 rotates the screw shaft 21, the moving table 11 is guided by the pair of linear guides 13 and moves back and forth linearly together with the nut 23.

[0013] The ball screw feed device 20 comprises a screw shaft 21 having a spiral screw groove 21b formed on its outer peripheral surface, a nut 23 arranged around the screw shaft 21, having a spiral screw groove (not shown) formed on its inner peripheral surface, and fitted into a nut housing 22 fixed to the underside of the moving table 11, and a plurality of balls (not shown) arranged so as to roll freely between the screw groove of the nut 23 and the screw groove 21b of the screw shaft 21.

[0014] The screw shaft 21 includes a large-diameter portion 24 formed in the axial center and having a screw groove 21b, and small-diameter portions 25 formed at both axial ends of the large-diameter portion 24. A male thread 25a is formed on the outer peripheral surface of the tip end of the small-diameter portion 25, and a small-diameter shaft portion 27 is provided at the tip end of one side (the right side in the figure) of the screw shaft 21. The small-diameter shaft portion 27 is connected to the rotating shaft 12a of the drive motor 12 via a coupling 28.

[0015] In addition, one side of the screw shaft 21, to which the drive motor 12 is connected, is rotatably supported by a first support mechanism 30, and the other side of the screw shaft 21 (the left side in the figure) is rotatably supported by a second support mechanism 40.

[0016] The first support mechanism 30 includes a fixed-side bearing housing 31 fixed to the base 1, and a pair of angular contact ball bearings 33, 33 arranged in a face-to-face combination to rotatably support the screw shaft 21 relative to the fixed-side bearing housing 31. Each of the pair of angular contact ball bearings 33, 33 includes an outer ring 34 fitted inside the fixed-side bearing housing 31, an inner ring 35 fitted outside the small diameter portion 25 of the screw shaft 21, and a plurality of balls 36 rollably disposed between the outer ring 34 and the inner ring 35 with a contact angle therebetween.

[0017] The pair of angular contact ball bearings 33, 33 has an outer ring 34 of the axially inner angular contact ball bearing 33 abutting against the inward flange 31a of the fixed-side bearing housing 31, and the outer ring 34 of the axially outer angular contact ball bearing 33 fixed by an outer ring holder 37 fastened to the fixed-side bearing housing 31. The inner ring 35 of the axially inner angular contact ball bearing 33 abuts against the step 21a between the large-diameter portion 24 and the small-diameter portion 25 of the screw shaft 21, and the inner ring 35 of the axially outer angular contact ball bearing 33 is fastened by a fastening nut 38a that screws onto the male threads 25a. Therefore, the first support mechanism 30 supports the screw shaft 21 with the axial position of the screw shaft 21 fixed.

[0018] 2 and 3, the second support mechanism 40 includes a bearing unit 41 disposed at the other end of the screw shaft 21, a support base 43 fixed to the base 1 axially centrally of the bearing unit 41, and a housing position adjustment mechanism 60 disposed between the bearing unit 41 and the support base 43. The support base 43 is provided with a through-hole 43a through which the screw shaft 21 passes.

[0019] The bearing unit 41 includes a moving-side bearing housing 51 and a pair of angular contact ball bearings 53, 53 that rotatably support the screw shaft 21 relative to the moving-side bearing housing 51. The pair of angular contact ball bearings 53, 53 include an outer ring 54 that fits inside the moving-side bearing housing 51, an inner ring 55 that fits outside the small diameter portion 25 of the screw shaft 21, and a plurality of balls 56 that are rotatably disposed between the outer ring 54 and the inner ring 55 with a contact angle therebetween.

[0020] In the pair of angular contact ball bearings 53, 53, the outer ring 54 of the axially inner angular contact ball bearing 53 abuts against the inward flange 51 a of the moving-side bearing housing 51, and the outer ring 54 of the axially outer angular contact ball bearing 53 is fastened by an outer ring holder 47 fastened and fixed to the moving-side bearing housing 51, so that each outer ring 54, 54 is positioned axially with respect to the moving-side bearing housing 51. Also, the inner ring 55 of the angular contact ball bearing 53 arranged axially outward is fastened by a fastening nut 38 b that threads onto the male thread 25 a via a spacer 48. In other words, the pair of angular contact ball bearings 53, 53, the moving-side bearing housing 51, and the outer ring holder 47 can be unitized as a bearing unit 41 with a predetermined preload applied to the pair of angular contact ball bearings 53, 53 arranged face-to-face, and this bearing unit 41 can be easily attached to the screw shaft 21 and the housing position adjustment mechanism 60, respectively. In this configuration, the moving-side bearing housing 51 can be integrated with the bearing housing side member 62 as needed.

[0021] The housing position adjustment mechanism 60 is provided on the support base 43 side and includes a support base side member 61 through which the screw shaft 21 passes, and a bearing housing side member 62 provided on the movable-side bearing housing 51 side and movable in the axial direction relative to the support base side member 61. The support base side member 61 and the bearing housing side member 62 face each other in the axial direction.

[0022] The support base side member 61 has an annular portion 61a protruding toward the support base 43 side, which fits into a through hole 43a of the support base 43, and is fixed to the support base 43 with a plurality of bolts (not shown). The bearing housing side member 62 has an annular portion 62a protruding toward the moving-side bearing housing 51 side, which fits into the inward flange 51a, and is fixed to the moving-side bearing housing 51 with a plurality of bolts 63 (see FIG. 3).

[0023] Furthermore, a bottomed annular recess 64 that opens toward the support base side member 61 (one axial side) is provided on the side surface of the bearing housing side member 62 facing the support base side member 61. Meanwhile, an annular protrusion 65 that protrudes into the annular recess 64 toward the bearing housing side member 62 (the other axial side) is provided on the side surface of the support base side member 61 facing the bearing housing side member 62. The annular recess 64 and the annular protrusion 65 are slidably fitted together in the axial direction, and an annular space (accommodation space) 66 is formed between the bottom surface, inward surface 64a, and outward surface 64b of the annular recess 64 and the tip surface of the annular protrusion 65.

[0024] An annular partition member 83 having an outer peripheral surface and an inner peripheral surface that are in sliding contact with the inward surface 64a and the outward surface 64b of the annular recess 64 is disposed within the annular space 66. As a result, the annular space 66 is divided in the axial direction by the partition member 83 into a first space 66A and a second space 66B.

[0025] The first space 66A contains a plurality of disc springs (elastic members) 70 and a first working fluid 80 in a compressed state as a first pressure generating means, and the second space 66B contains a foam member 90 and a second working fluid 81 in a compressed state as a second pressure generating means.

[0026] The plurality of disc springs 70 are arranged in a compressed state between the opposing axial end faces of the bearing housing side member 62 and the partition member 83. When the plurality of disc springs 70 function as series springs, they are arranged to be stacked in the axial direction so that the convex surfaces of adjacent disc springs 70 face each other and the concave surfaces of adjacent disc springs 70 face each other, as shown in Fig. 2. When the plurality of disc springs 70 function as parallel springs, they are arranged so that the disc springs 70 face each other and face each other in the axial direction, although this is not shown.

[0027] The foam member 90 is configured to provide a sealed structure, and is formed in an annular shape with an elliptical cross section having an inner diameter larger than the outward surface 64b of the annular recess 64 and an outer diameter smaller than the inward surface 64a of the annular recess 64. As shown in Figure 4, the foam member 90 is composed of a foam core layer 86 having a large number of pores 86a and a solid skin layer 87 without pores 86a that surrounds the foam core layer 86. The foam core layer 86 preferably has a closed-cell structure in which the individual pores 86a are independent so as to continuously generate stable rigidity as the foam member 90, but may also have an open-cell structure in which some adjacent pores 86a are connected to each other.

[0028] The foam member 90 can be manufactured by a foam injection molding method or a foam extrusion molding method using a foamable resin material. Examples of resins include various thermoplastic resins, specifically, polyolefins such as high-pressure low-density polyethylene, which is a homopolymer or copolymer of α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene, linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), polypropylene (propylene homopolymer), propylene random copolymer, propylene block copolymer, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene random copolymer, ethylene-1-butene random copolymer, and propylene-1-butene random copolymer, polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamides (nylon-6, nylon-66, polymetaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-acrylic acid ester-carbon monoxide copolymer, polyacrylonitrile-butadiene copolymer, and the like. Examples of suitable resins include those known as engineering plastics, such as nitrile, polycarbonate, polystyrene, ionomer, polyacetal, modified polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyetheretherketone, polyetherimide, and polyamideimide, as well as mixtures thereof. Among these, high-pressure low-density polyethylene, linear low-density polyethylene, high-density polyethylene, propylene-based polymers such as polypropylene and propylene random copolymers and propylene block copolymers, polyethylene terephthalate, polyamide, and engineering plastics are preferred. These thermoplastic resins may be used alone or in combination. However, because the solid skin layer 87 comes into contact with the working fluid 70, resins with low reactivity with the working fluid 70 are selected from these resins.

[0029] The foaming agent may be a chemical foaming agent or a physical foaming agent, and therefore may be a solvent-type foaming agent or a decomposition-type foaming agent, or may be a gaseous foaming agent such as nitrogen, carbon dioxide, argon, or air, or a thermal expansion type microcapsule foaming agent.

[0030] FIG. 5 is a schematic diagram illustrating the process for producing a foam member 90. As shown in FIG. 5( a), a base resin and a foaming agent are supplied from a hopper 96 to an injection molding machine 95, and the resulting mixed foaming-agent-containing resin material 99 is supplied and filled into the cavity of a mold 98 having a fixed mold 98A and a movable mold 98B. The foaming agent may be supplied separately into a cylinder 97. Next, as shown in FIG. 5( b), the movable mold 98B is cored back, the foaming agent is foamed, and the foaming-agent-containing resin material 99 in the cavity is solidified. This produces a foam member 90 having a foam core layer 86 with pores 86a formed therein and a solid skin layer 87 arranged around the foam core layer 86.

[0031] Furthermore, the foam member 90 may be formed by using rubber or a thermoplastic elastomer instead of resin as the base material, adding a foaming agent, and molding by injection, extrusion, press, etc. The foam member 90 may also be formed from a foamed metal material, as long as it has the same function. In this case, the metal material is preferably one that is highly durable and can continuously provide stable rigidity.

[0032] In addition, the foam member 90 may be manufactured by foaming a foam material inside an enclosed space formed by a housing having any shape, such as a cube, a rectangular parallelepiped, a sphere, a semicircular arc, or a ring. Furthermore, the foam member 90 may be manufactured by foaming a foam material inside an enclosed space, and then covering the outer surface of the solid skin layer 87 or the surface of a cut-out portion of the foam core layer 86 with a separately provided cover member 102 (see FIG. 6 ). The cover member may be configured to cover the entire foamed foam material as is, or may be configured to cover an arbitrarily cut-out portion of the foam material. The cover member provided separately from the foamed foam material may be made of any material that is impermeable to the working fluid 70.

[0033] 7( a), the foam member 90 includes a small-diameter ring 87A and a large-diameter ring 87B that are concentrically arranged to form a solid skin layer 87, and a foam core layer 86 that fills the space between the small-diameter ring 87A and the large-diameter ring 87B. Alternatively, the foam member 90 may further include a pair of annular plates 88 that close openings on both axial sides of the small-diameter ring 87A and the large-diameter ring 87B, as shown in FIG.

[0034] Here, the foam core layer 86 is formed by injecting a mixture of a base material and a foaming agent into the annular space partitioned by the small-diameter ring 87A, the large-diameter ring 87B, and a pair of annular plates 88, filling the space, and then foaming the foaming agent to form a foam. In the case of Figure 7(a), foaming is suppressed near the annular plate 88, and the base material essentially forms the solid skin layer 87. Therefore, the annular plate 88 can be removed to form the foam member 90. Note that, if the small-diameter ring 87A and the large-diameter ring 87B are configured to be separate from the foam member 90, the foam member 90 may be constructed by separating all of the components that form the sealed space.

[0035] 8, at least one outer layer 101 may be provided that covers the entire peripheral surface of the foam member 90 with a molded member. This allows the rigidity of the foam member 90 to be changed and also protects the surface of the foam member 90 from the working fluid 70. Note that the foam member 90 referred to here may be formed from any of the above-mentioned materials or by any of the above-mentioned molding methods, and includes foam members molded by an injection molding machine, foam members in which the components that constitute the sealed space are separated, foam members in which the components that constitute the sealed space are used as the foam member 90, and the like.

[0036] In the above embodiment, the foam member 90 is molded seamlessly as a single piece, which makes it difficult for localized stress concentrations to occur and allows for easy manufacturing. However, the foam member 90 is not limited to being molded as a single piece, and may be, for example, a combined body having a foamed cross section, which is formed by joining the end faces of two or more members to integrate these two or more members.

[0037] For example, as shown in Figure 9, divided pieces 90c1 to 90c4 of the foam member can be made into an arc shape, and their end faces can be connected to form a single annular foam member 90. By using a divided structure like this, the molding die 98 (see Figure 5) can be made smaller, making manufacturing easier. The connection method can be selected from among an appropriate adhesive, heat fusion, or a mechanical locking mechanism.

[0038] In the above embodiment, the foam member 90 has a rectangular or circular cross section, but is not limited thereto. It may have an elliptical cross section as shown in Fig. 10(a) or a triangular cross section as shown in Fig. 10(b), and may be formed into any other shape. Furthermore, in this embodiment, the foam member 90 is not limited to an annular shape and may be formed of one or more foam members having any shape, such as a cube, a rectangular parallelepiped, a sphere, or a semicircular arc. For example, as shown in Fig. 10(c), multiple foam members 90 may be disposed within the pressure chamber 66. Additionally, the peripheral surface of such a foam member having any shape, such as a cube, a rectangular parallelepiped, a sphere, or a semicircular arc, may be covered with the outer layer described above.

[0039] 10(d), a hollow member 100 can be mixed in the pressure chamber 66 together with the foam member 90. The hollow member 100 is made of elastically deformable rubber, resin, metal, etc., or a combination of these, and the hollow member 100 contains any liquid or gas that has an elastic effect when an external force is applied and whose rigidity has been industrially confirmed.

[0040] Furthermore, the working fluid may be any liquid such as oil or water, or a gas, which has an elastic effect when an external force is applied and whose rigidity has been industrially confirmed. In this embodiment, a gas is used as the first working fluid 80, and an oil is used as the second working fluid 81.

[0041] Therefore, in this embodiment, the first pressure generating means includes the disc spring 70 housed in the first space 66A and a first working fluid 80 filled in the first space 66A around the disc spring 70. The second pressure generating means includes the foam member 90 housed in the second space 66B and a second working fluid 81 filled in the second space 66B around the foam member 90.

[0042] Furthermore, O-rings 67A are fitted between the inward surface 64a of the annular recess 64 and the outer peripheral surface of the partition member 83, and between the outward surface 64b of the annular recess 64 and the inner peripheral surface of the partition member 83. Specifically, the O-rings 67A are disposed in annular seal grooves 68A formed in the outer peripheral surface and inner peripheral surface of the partition member 83, and come into sliding contact with the inward surface 64a and outward surface 64b of the opposing annular recess 64, thereby sealing the radial gap between the outer peripheral surface of the partition member 83 and the inward surface 64a of the annular recess 64, and the radial gap between the inner peripheral surface of the partition member 83 and the outward surface 64b of the annular recess 64.

[0043] Furthermore, O-rings 67 are fitted between the outward surface 65 a of the annular protrusion 65 and the inward surface 64 a of the annular recess 64, and between the inward surface 65 b of the annular protrusion 65 and the outward surface 64 b of the annular recess 64. Specifically, the O-rings 67 are arranged in annular seal grooves 68 formed in the outward surface 65 a and the inward surface 65 b of the annular protrusion 65 and come into sliding contact with the opposing inward surface 64 a and the outward surface 64 b of the annular recess 64 to seal the radial gap between the outward surface 65 a of the annular protrusion 65 and the inward surface 64 a of the annular recess 64, and the radial gap between the inward surface 65 b of the annular protrusion 65 and the outward surface 64 b of the annular recess 64. Note that the seal grooves 68 may be formed in the inward surface 64 a and the outward surface 64 b of the annular recess 64. Furthermore, although one O-ring 67, 67A and one seal groove 68, 68A are disposed between each opposing surface, multiple O-rings 67, 67A may be disposed between each opposing surface. This allows the O-rings 67, 67A to prevent leakage of the first working fluid 80 filled in the first space 66A and the second working fluid 81 filled in the second space 66B. The O-ring 67 may be subjected to a surface treatment that provides wear resistance or the like in order to prevent wear.

[0044] An anti-rotation mechanism 75 is provided between the support base side member 61 and the bearing housing side member 62 to prevent relative rotation therebetween. Specifically, for example, the bearing housing side member 62 has a through-hole 77 formed in at least one location in the circumferential direction, which penetrates radially so that the tip of a positioning pin 76 protrudes from the inward surface 64a of the annular recess 64. The tip of the positioning pin 76 is inserted into an elongated hole 78 formed along the axial direction in the outward surface 65a of the annular protrusion 65 of the support base side member 61 so that the bearing housing side member 62 can move in the axial direction. Note that the positioning pin 76 may be replaced by a rotational positioning key (not shown) having a similar anti-rotation function, which is inserted into the elongated hole 78 so that the bearing housing side member 62 can move in the axial direction.

[0045] In addition, a storage chamber 71 is formed within the annular protrusion 65, and an orifice 72 is formed along the axial direction at at least one location (two locations in Figure 2) in the circumferential direction to connect the storage chamber 71 to the annular space 66.

[0046] The reservoir chamber 71 is formed in a disk groove shape, opening onto the outward surface 65a of the annular protrusion 65, closer to the tip surface of the annular protrusion 65 than the seal groove 68 in which the O-ring 67 is disposed. Therefore, in this embodiment, the second working fluid 81 is stored not only in the second space 66B but also in the reservoir chamber 71 and the orifice 72.

[0047] In this housing position adjustment mechanism 60, the partition member 83 is used to accommodate the disc springs 70 and the first working fluid 80 in the first space 66A and the foamed material 90 and the second working fluid 81 in the second space 66B. Then, by tightening the fastening nut 38b, the bearing housing side member 62 is pressed toward the support base side member 61 via the pair of angular ball bearings 53 and the moving-side bearing housing 51. As a result, in the first space 66A, the disc springs 70 and the first working fluid 80 are compressed, and pressure in the screw axis direction is applied to the disc springs 70 and the first working fluid 80. In the second space 66B, the foamed material 90 and the second working fluid 81 are compressed, and pressure in the screw axis direction is applied to the foamed material 90 and the second working fluid 81.

[0048] On the other hand, because the support base side member 61 is fixed to the base 1 via the support base 43, the bearing housing side member 62 and the movable-side bearing housing 51 are pressed leftward in the figure by the pressure of the multiple disc springs 70 and the first working fluid 80 housed in the first space 66A in a compressed state, and the foamed member 90 and the second working fluid 81 housed in the second space 66B. This brings about a state in which tension is preliminarily applied to the screw shaft 21 leftward in Figures 1 and 2.

[0049] Furthermore, the pressure of the plurality of disc springs 70 and the first working fluid 80 housed in the first space 66A and the pressure of the foamed material 90 and the second working fluid 81 housed in the second space 66B can be controlled to any magnitude by the amount of tightening of the fastening nut 38b. That is, the magnitude of the axial load applied to the screw shaft 21 by the fastening nut 38b can be set to any magnitude by the total pressure in the screw axial direction generated by the plurality of disc springs 70 and the first working fluid 80 in a compressed state, and the foamed material 90 and the second working fluid 81, and desired compression characteristics can be imparted.

[0050] Next, we will explain the operation of the ball screw feed device 20 of this embodiment. In the ball screw feed device 20, when the screw shaft 21 is rotationally driven by the drive motor 12 and the moving table 11 fixed to the nut 23 is caused to move linearly back and forth, the drive motor 12, angular contact ball bearings 33, 53, nut 23, etc. generate heat in association with this movement, the temperature of the ball screw feed device 20 gradually rises, and the screw shaft 21 extends in the axial direction due to thermal expansion.

[0051] In the ball screw feed device 20 of this embodiment shown in FIG. 1 , when the screw shaft 21 thermally expands and elongates in the axial direction, the right end of the screw shaft 21 extends leftward because the right end of the screw shaft 21 is fixed to the fixed-side bearing housing 31 via the angular contact ball bearings 33. When the screw shaft 21 extends axially (leftward) due to the influence of heat, the bearing unit 41 and the bearing housing side member 62 move in the same direction as the axial extension of the screw shaft 21 due to thermal expansion due to the pressure of the multiple disc springs 70 and the first working fluid 80 disposed in the first space 66A and the foamed member 90 and the second working fluid 81 disposed in the second space 66B. In particular, because the foamed member 90 is accommodated in the second space 66B so as to float via the second working fluid 81, the pressure generated by the foamed member 90 is transmitted to the bearing unit 41 and the bearing housing side member 62 via the second working fluid 81.

[0052] In this embodiment, the disc springs 70 and the first working fluid, and the foamed member 90 and the second working fluid 81 are designed to continue to press the bearing unit 41 and the bearing housing side member 62 to the left even when the screw shaft 21 extends in the axial direction. The disc springs 70, the foamed member 90, and the annular space 66 have a high degree of design freedom, and by appropriately selecting the physical properties of the working fluid filled in the annular space and the size and shape of the annular space, a sufficient and appropriate load can be applied to accommodate greater axial extension. Therefore, even if the temperature of the ball screw feed device 20 rises above 4 degrees, the pair of angular contact ball bearings 53 can be moved axially to maintain axial support rigidity, and the axial rigidity of the ball screw feed device 20 is stabilized.

[0053] In particular, the pressure exerted by the multiple disc springs 70 and the foam material 90 can change in response to the axial elongation of the screw shaft 21 even when the temperature rises by more than 4 degrees, so that while the screw shaft 21 is elongating in the axial direction, the axial rigidity of the ball screw feed device 20 is stabilized while maintaining the pair of angular ball bearings 33, 33 as fixed support parts.

[0054] In this case, an excessive load is not applied to the pair of angular ball bearings 33, 33 and 53, 53, so there is no risk of excessive wear or seizure due to poor lubrication, and the life of the pair of angular ball bearings 33, 33 and 53, 53 is extended. That is, in this embodiment, it is no longer necessary to apply to the screw shaft 21 a pretension of the magnitude that is applied by the spacer in the ball screw described in Patent Document 1, so an excessive load is not applied to the pair of angular ball bearings 33, 33 and 53, 53 either.

[0055] Furthermore, in the ball screw feed device 20 of this embodiment, it is not necessary to install an external device such as an accumulator or pump for supplying the working fluids 80, 81 to the annular space 66, and the housing position adjustment mechanism 60 can be simplified. As a result, the pressure in the annular space 66 can be maintained with as little change as possible without consuming energy supplied from the outside. Note that the ball screw feed device 20 of this embodiment may be configured to be provided with an external device for supplying the working fluid to the outside.

[0056] The O-rings 67, 67A in this embodiment also function as a damping mechanism. That is, when a workpiece placed on the movable table 11 is machined, vibrations generated in the movable table 11 tend to vibrate the screw shaft 21, which has a relatively low rigidity. The vibrations of the screw shaft 21 are propagated to the bearing housing side member 62 via the pair of angular contact ball bearings 33, 33 and the movable-side bearing housing 51. However, the O-rings 67, 67A between the bearing housing side member 62 and the support base side member 61 damp the vibrations of the bearing housing side member 62. Therefore, the vibrations of the screw shaft 21 can also be damped, thereby suppressing disturbances in the quality of the machined surface of the workpiece placed on the movable table 11. In this case, the O-rings 67, 67A disposed between the bearing housing side member 62 and the support base side member 61 damp not only the axial vibrations of the screw shaft 21 but also the radial vibrations of the screw shaft 21.

[0057] Furthermore, the first and second working fluids 80, 81 of the housing position adjustment mechanism 60 are stored not only in the first space 66A and the second space 66B, but also in the gaps between the outward surface 65a of the annular convex portion 65 and the inward surface 64a of the annular recessed portion 64, and between the inward surface 65b of the annular convex portion 65 and the outward surface 64b of the annular recessed portion 64, and in the gaps closer to the annular space 66 than the O-ring 67. Therefore, the first and second working fluids 80, 81 support the bearing housing side member 62 with a sufficient and appropriate radial load against the support base side member 61. As a result, the housing position adjustment mechanism 60 can provide radial support rigidity to the screw shaft 21 via the pair of angular contact ball bearings 53, 53 and the bearing housing 51, and can also have an aligning function for the screw shaft 21.

[0058] Furthermore, in this embodiment, vibration of the screw shaft 21 causes the bearing housing side member 62 to vibrate together with the movable-side bearing housing 51 and the pair of angular contact ball bearings 33, 33, and the second working fluid 81 in the annular space 66 and the reservoir chamber 71 passes through the orifice 72 and the gap g between the outward surface 65 a of the annular convex portion 65 and the inward surface 64 a of the annular concave portion 64, thereby damping the vibration. Therefore, similar to the O-rings 67, 67A described above, when a workpiece placed on the moving table 11 is machined, the vibration transmitted to the screw shaft 21 can be damped, further improving the quality of the machined surface of the workpiece.

[0059] The second working fluid 81 can exert the damping function of the screw shaft 21 described above by passing through the gap g between the annular convex portion 65 and the annular concave portion 64 and by flowing through the storage chamber 71 and the orifice 72.

[0060] Therefore, according to the ball screw feed device 20 of this embodiment, by arranging a partition member 83 in the annular space 66, the two types of pressure-generating members contained in the annular space 66, namely, the multiple disc springs 70 and the first working fluid 80, and the foamed member 90 and the second working fluid 81, can continuously and stably maintain axial support rigidity even if the axial length of the screw shaft 21 changes due to the influence of heat, and can damp vibrations in the axial and radial directions.

[0061] 11 , the partition member 83 may be elongated in the axial direction and two O-rings 67A may be arranged side by side in the axial direction to improve sealing performance and damping mechanism. The partition member 83 may also have an annular groove 84 formed in a radially intermediate portion thereof, the annular groove 84 opening to one of the axial side surfaces. This allows the working fluid to be contained in the annular groove 84, and the housing position adjustment mechanism 60 can be maintained in a compact configuration. The annular groove 84 is not limited to being open to one of the axial side surfaces, but may be formed on both axial sides so as to open to both axial side surfaces.

[0062] 12, the tip surface 65c of the annular protrusion 65 of the support base side member 61 may be formed in a pointed convex tapered shape from the inner peripheral edge to the outer peripheral edge so that the axial length of the second space 66B gradually increases radially outward. This allows the second working fluid 81 in the second space 66B to better align the bearing housing side member 62 with the support base side member 61, thereby further improving the aligning function of the pair of angular contact ball bearings 53, 53 with the screw shaft 21.

[0063] Although not shown, if the tip surface 65c of the annular convex portion 65 of the support base side member 61 has a convex tapered shape from the outer peripheral edge to the inner peripheral edge, the coaxiality of the pair of angular ball bearings 53, 53 with respect to the screw shaft 21 can be improved.

[0064] 2 is provided with a reservoir chamber 71 that communicates with the second space 66B via an orifice 72, and a second working fluid 81 that constitutes the second pressure generating means is accommodated in a compressed state not only in the second space 66B but also in the reservoir chamber 71 and the orifice 72. However, as shown in FIG. 12, the annular convex portion 65 may be configured without the reservoir chamber 71 or the orifice 72, and in this case, the second working fluid 81 is accommodated in a compressed state in the second space 66B.

[0065] Furthermore, as another variation of this embodiment, as shown in Figure 13, a foaming member 90 configured based on a sealed structure may be configured to be placed in a storage chamber 71 communicating with the second space 66B instead of the second space 66B.

[0066] In this case, the second pressure generating means is configured to include a second working fluid 81 stored in a compressed state in the second space 66B, the storage chamber 71, and the orifice 72, and a foaming member 90 stored in the storage chamber 71.

[0067] Although not shown, the support base side member 61 may be configured integrally with the support base 43 , and the bearing housing side member 62 may be configured integrally with the moving side bearing housing 51 .

[0068] Second Embodiment Next, a ball screw feed device according to a second embodiment of the present invention will be described with reference to Figures 14 and 15. Note that in this embodiment, the configuration of the housing position adjustment mechanism 60 of the second support mechanism 40 is different from that of the first embodiment.

[0069] In the housing position adjustment mechanism 60 of the second embodiment, the seal groove 68 formed on the outward surface 65a and the inward surface 65b of the annular convex portion 65 and the seal groove 68A formed on the outer surface and the inner surface of the partition member 83 are composed of a tapered surface 69a whose groove depth becomes shallower as it moves away from the second space 66B side, and circular axial side surfaces 69b, 69c extending radially from both axial end edges of the tapered surface 69a.

[0070] The axial distance between the axial side surfaces 69b, 69c is wider than the axial width of the O-ring 67 when it is elastically deformed and attached to the seal grooves 68, 68A. This allows the second working fluid 81 that has passed through the gap g from the second space 66B to reach the vicinity of the boundary between the axial side surface 69b, which has a deeper groove, and the tapered surface 69a.

[0071] Therefore, as the pressure of the second working fluid 81 in the second space 66B increases and the O-ring 67 is pushed toward the atmospheric pressure side or the first space 66A side by the second working fluid 81, the O-ring 67 further improves the sealing performance due to the wedge structure between the tapered surfaces 69a of the seal grooves 68, 68A and the inward surface 64a or outward surface 64b of the opposing annular recess 64. As a result, even if relative movement occurs between the support base side member 61 and the bearing housing side member 62, leakage of the second working fluid 81 toward the atmospheric pressure side or the first space 66A side can be prevented, and the axial rigidity of the ball screw feed device 20 can be continuously maintained.

[0072] As a modification of this embodiment, as shown in Figures 16(a) to (c), a wear-resistant member 59 may be interposed between the O-ring 67 and at least one of the inward surface 64a of the annular recess 64 and the outward surface 65a of the annular protrusion 65 (in this embodiment, the tapered surface 69a of the seal groove 68 formed on the outward surface 65a).

[0073] Specifically, as shown in FIG. 16( a), the wear-resistant member 59 may be formed as an annular member having a U-shaped cross section so as to be positioned between the outer peripheral surface of the O-ring 67 and the inward surface 64 a of the annular recess 64, and between the inner peripheral surface of the O-ring 67 and the tapered surfaces 69 a of the seal grooves 68, 68A formed on the outward surface 65 a of the annular protrusion 65.

[0074] 16(b), the wear-resistant member 59 may be formed as an annular member having a straight cross section so as to be positioned between the inner peripheral surface of the O-ring 67 and the tapered surface 69a of the seal groove 68, 68A formed in the outward surface 65a of the annular convex portion 65. Furthermore, as shown in Fig. 16(c), the wear-resistant member 59 may be formed as an annular member having a straight cross section so as to be positioned between the outer peripheral surface of the O-ring 67 and the inward surface 64a of the annular recess 64.

[0075] The wear-resistant member 59 may be made of, for example, a resin material such as a fluorine-based resin, or a metal material that has been subjected to an appropriate surface treatment.

[0076] In any of the embodiments shown in Figures 16(a) to (c), the use of the wear-resistant member 59 can disperse the stress concentration on the O-ring 67, thereby suppressing damage such as wear to the O-ring 67 and the contact surface with the O-ring 67.

[0077] In addition, the wear-resistant member 59 may also be interposed between the O-ring 67 and at least one of the outward surface 64b of the annular recess 64 and the inward surface 65b of the annular protrusion 65 (in FIG. 15, the tapered surface 69a of the seal groove 68 formed on the inward surface 65b), as shown in FIG.

[0078] 16(a) to 16(c), the wear-resistant member 59 is disposed in a seal groove 68 having a tapered surface 69a, between the O-ring 67 and the opposing surface of the O-ring 67. On the other hand, the above effect can also be achieved by disposing the wear-resistant member 59 between the O-ring 67 and the opposing surface of the O-ring 67 in a seal groove 68 having a uniform groove depth, as shown in FIG.

[0079] The wear-resistant member 59 may be interposed between the O-ring 67 and at least one of the inward surface 64a of the annular recess 64 and the outer peripheral surface of the partition wall member 83 (in this embodiment, the seal groove 68A formed on the outer peripheral surface). The wear-resistant member 59 may be interposed between the O-ring 67 and at least one of the outward surface 64b of the annular recess 64 and the inner peripheral surface of the partition wall member 83 (in this embodiment, the seal groove 68A formed on the inner peripheral surface).

[0080] 17( a) to 17(d), the seal groove 68A formed in the outer peripheral surface and the inner peripheral surface of the partition member 83 may have a V-shaped groove bottom 69a1 that gradually deepens from both axial side surfaces 69b, 69c toward the axial middle. The O-ring 67 is interposed between two tapered surfaces that form the groove bottom 69a1 and the inward surface 64a of the annular recess 64 (or the outward surface 64b of the annular recess 64) to seal the first working fluid 80 in the first space 66A and the second working fluid 81 in the second space 66B. When the O-ring 67 moves along the tapered surface of the groove bottom 69a1 toward one of the axial side surfaces 69b, 69c in response to the pressure difference between the first space 66A and the second space 66B, a wedge action is generated, improving the sealing performance for the first and second working fluids 80, 81. Depending on the pressure difference between the first space 66A and the second space 66B, the partition member 83 itself may move in the axial direction, in which case the contact position between the groove bottom surface 69a1 of the partition member 83 and the O-ring 67 changes.

[0081] 17(b) to 17(d), the wear-resistant member 59 may be interposed between the O-ring 67 and at least one of the inward surface 64a of the annular recess 64 and the outer peripheral surface of the partition wall member 83 (in this embodiment, the seal groove 68A formed on the outer peripheral surface). The wear-resistant member 59 may also be interposed between the O-ring 67 and at least one of the outward surface 64b of the annular recess 64 and the inner peripheral surface of the partition wall member 83 (in this embodiment, the seal groove 68A formed on the inner peripheral surface). The other configurations and functions are similar to those of the first embodiment.

[0082] Third Embodiment Next, a ball screw feed device according to a third embodiment of the present invention will be described with reference to Fig. 18. Note that in this embodiment, the configuration of the housing position adjustment mechanism 60 of the second support mechanism 40 is different from that of the first embodiment.

[0083] In the housing position adjustment mechanism 60 of the third embodiment, heating elements 130, 131, such as heating wires or rubber heaters, serving as working medium volume change parts, are arranged in a ring shape or discretely on the outer circumferential surfaces of the support base side member 61 and the bearing housing side member 62.

[0084] As a result, heat from the heating elements 130, 131 is transferred from the support base side member 61 and the bearing housing side member 62 to the foamed material 90 and the first and second working fluids 80, 81 in the first and second spaces 66A, 66B, and by heating the foamed material 90 and the first and second working fluids 80, 81, the overall volumes of the foamed material 90 and the first and second working fluids 80, 81 can be expanded. As a result, even if the screw shaft 21 elongates in the axial direction, a load is excited in the first and second spaces 66A, 66B due to the volumetric expansion of the foamed material 90 and the first and second working fluids 80, 81, and therefore, the axial support rigidity can be maintained.

[0085] In this embodiment, heating elements 130, 131 are attached to the outer peripheral surfaces of the support base side member 61 and the bearing housing side member 62 as working medium volume change units, but cooling media 132, 133 such as a cooling jacket or a cooling element may be attached instead.

[0086] By using the cooling media 132, 133, even if the load excited in the first and second spaces 66A, 66B becomes excessive due to the volume expansion of the foamed member 90 and the first and second working fluids 80, 81, it is possible to cool the foamed member 90 and the first and second working fluids 80, 81 and shrink the overall volume of the foamed member 90 and the first and second working fluids 80, 81. This prevents the axial support stiffness of the ball screw feed device 20 from becoming excessively large, and makes it possible to continuously maintain the axial support stiffness in a stable state.

[0087] In addition, in this embodiment, the temperatures of the foamed member 90 and the first and second working fluids 80, 81 are affected by the components, installation environment, operating cycle, etc. of the ball screw feed device 20, and therefore the foamed member 90 and the first and second working fluids 80, 81 may be controlled to target temperatures by forming a feedback loop for the temperatures of the components, the foamed member 90, the first and second working fluids 80, 81, etc. using the heating elements 130, 131 and the cooling media 132, 133. Furthermore, in this embodiment, the operation of the heating elements 130, 131 and the cooling media 132, 133 may be feedback-controlled by taking into consideration volumetric changes of the first and second working fluids 80, 81, the pressure states in the first and second spaces 66A, 66B, and the relative axial displacement between the support base side member 61 and the bearing housing side member 62, etc.

[0088] In addition, in this embodiment, the working medium volume change unit is attached to both the support base side member 61 and the bearing housing side member 62, but it may also be attached to either the support base side member 61 or the bearing housing side member 62.

[0089] Furthermore, in this embodiment, the working fluid volume change units are provided on the outer peripheral surfaces of the support base side member 61 and the bearing housing side member 62. However, they may be attached to any location, such as the axial side, inner peripheral surface, or interior, as long as they can expand or contract the volume of the foam member 90 and the first and second working fluids 80, 81 in the first and second spaces 66A, 66B. In addition, a heating element may be attached to either the support base side member 61 or the bearing housing side member 62, and a cooling medium may be attached to the other. Furthermore, the heating element and the cooling medium may be arranged so as to coexist in either the support base side member 61 or the bearing housing side member 62. Other configurations and operations are the same as those of the first embodiment.

[0090] Fourth Embodiment Next, a ball screw feed device according to a fourth embodiment of the present invention will be described with reference to Fig. 19. Note that this embodiment differs from the first embodiment in that the second support mechanism 40 further includes another housing position adjustment mechanism 160.

[0091] That is, the second support mechanism 40 of the fourth embodiment further includes an other housing position adjustment mechanism 160 disposed adjacent to the housing position adjustment mechanism 60 between the bearing unit 41 and the support base 43. The other housing position adjustment mechanism 160 includes: an other support base side member 161 provided on the support base 43 side and through which the screw shaft 21 passes; an other bearing housing side member 162 provided on the bearing housing 51 side and through which the screw shaft 21 passes and which is movable in the axial direction relative to the other support base side member 161; and a partition member 183 disposed in another accommodation space formed between the other support base side member 161 and the other bearing housing side member 162 and which axially divides the other accommodation space into a third space 166A and a fourth space 166B. Furthermore, another housing position adjustment mechanism 160 includes a plurality of disc springs 70 and a first working fluid 80 as third pressure generating means housed in a compressed state in a third space 166A, and a foam member 90 and a second working fluid 81 as fourth pressure generating means housed in a compressed state in a fourth space 166B. In other words, the second support mechanism 40 has two housing position adjustment mechanisms 60, 160 in a tandem configuration arranged in series in the axial direction.

[0092] As shown in Figure 19, in the other housing position adjustment mechanism 160, the other bearing housing side member 162 has an annular recess 164, and the other support base side member 161 has an annular protrusion 165 that fits axially within the annular recess 164, and in the other storage space formed between the other support base side member 161 and the other bearing housing side member 162, a third pressure generating means and a fourth pressure generating means are arranged via a partition member 183.

[0093] In this embodiment, the other support base side member 161 has an annular portion 161a protruding toward the support base 43 and fitted into a through hole 43a of the support base 43, and is fixed to the support base 43 with a plurality of bolts (not shown). Furthermore, the support base side member 61 of the housing position adjustment mechanism 60 and the other bearing housing side member 162 of the other housing position adjustment mechanism 160 are integrally configured as a single member or by connecting the two.

[0094] In this way, by arranging the two housing position adjustment mechanisms 60, 160 in series in the axial direction, it is possible to stably maintain the axial rigidity of the ball screw feed device 20 even when the extension of the screw shaft is even greater, and it is also possible to improve axial alignment and coaxiality.

[0095] The other housing position adjustment mechanism 160 is not limited to the same configuration as the housing position adjustment mechanism 60 shown in FIG. 19 , but may have at least a third pressure generating means accommodated in a compressed state in another accommodation space formed between the other support base side member 161 and the other bearing housing side member 162. For example, the other accommodation space may not be provided with a partition member, and only a plurality of disc springs 70 may be disposed as the third pressure generating means. Furthermore, the second support mechanism 40 may have two housing position adjustment mechanisms 60, 160, or may have three or more housing position adjustment mechanisms, as long as the plurality of housing position adjustment mechanisms are arranged in series in the axial direction. The other configurations and operations are the same as those of the first embodiment.

[0096] In the first to fourth embodiments, the pair of angular contact ball bearings used in the bearing unit of the second support mechanism are arranged in a face-to-face configuration, but the arrangement is not limited to this. That is, the pair of angular contact ball bearings 53, 53 may be arranged in various support configurations, such as a back-to-back configuration as shown in FIG. 20 or a parallel configuration as shown in FIG. 21 . When the pair of angular contact ball bearings 53, 53 are arranged in a back-to-back configuration as shown in FIG. 20 , an inner ring spacer 49 may be disposed between the step between the large-diameter portion 24 and the small-diameter portion 25 of the screw shaft 21 and the inner ring 55 of the angular contact ball bearing 53 on the axially inner side. Furthermore, while the pair of angular contact ball bearings 33, 33 of the first support mechanism are also arranged in a face-to-face configuration, they may be arranged in various support configurations, such as a back-to-face configuration or a parallel configuration. Furthermore, although not shown, the angular contact ball bearings 33, 53 do not necessarily have to be composed of two angular contact ball bearings, but may be composed of three or more angular contact ball bearings.

[0097] Furthermore, in the above embodiment, the other housing position adjustment mechanism 160 is disposed adjacent to the housing position adjustment mechanism 60 in the axial direction, but this is not limiting, and the other housing position adjustment mechanism 160 may be disposed adjacent to the housing position adjustment mechanism 60 in parallel in the radial direction. This makes it possible to maintain the axial rigidity of the ball screw feed device 20 while suppressing the axial dimension of the ball screw feed device 20 and in a state in which a larger axial load is generated than when a single housing position adjustment mechanism is disposed.

[0098] Furthermore, in the above embodiment, the annular recess is provided on the bearing housing side member and the annular protrusion is provided on the support base side member, but the present invention is not limited to this, and the annular recess may be provided on the support base side member and the annular protrusion may be provided on the bearing housing side member.

[0099] Furthermore, in the above embodiment, the annular space 66 is formed in an annular shape by the annular recess 64 and the annular protrusion 65, but a plurality of recesses and protrusions may be formed in the circumferential direction, and partition members may be disposed in each of the plurality of storage spaces. In this case, an O-ring may be disposed between the inner peripheral surface of the recess and the outer peripheral surface of the protrusion to provide a configuration with fluid leakage and damping functions, or a storage chamber opening onto the outer peripheral surface of the protrusion and an orifice communicating the storage chamber with the second space may be provided to provide an additional damping function.

[0100] For example, as shown in FIG. 22( a), four circumferentially arranged accommodation spaces 66y may be arranged around the screw shaft 21. As shown in FIG. 22( b), two adjacent accommodation spaces 66y arranged side by side in the radial direction may be arranged at four circumferentially arranged locations, i.e., a total of eight accommodation spaces 66y may be arranged around the screw shaft 21. Alternatively, as shown in FIG. 23( a), two circumferentially arranged accommodation spaces 66y, i.e., accommodation spaces 66y on both sides of the width direction (Y direction) of the screw shaft 21, may be arranged around the screw shaft 21. As shown in FIG. 23( b), three adjacent accommodation spaces 66y arranged side by side in the radial direction (width direction in this example) may be arranged at two circumferentially arranged locations, i.e., a total of six accommodation spaces 66y may be arranged around the screw shaft 21. In this case, the height dimensions of the support base side member 61 and the bearing housing side member 62 can be reduced.

[0101] 24, two accommodation spaces 66y may be provided around the screw shaft 21, i.e., accommodation spaces 66y on both sides in the vertical direction with respect to the screw shaft 21. In this case, the width dimensions of the support base side member 61 and the bearing housing side member 62 can be reduced.

[0102] 25 is a schematic cross-sectional view taken along line XXV-XXV in FIG. 23(a). In this case, the two storage spaces 66y are each formed of a recess 64x and a protrusion 65x. In the drawing, the protrusion 65x is integral with the base of the support base member 61, but it may be formed separately from the base and then joined.

[0103] The multiple accommodation spaces 66y can be arranged arbitrarily as long as the bearing unit 41 and the bearing housing side member 62 can move stably in the same direction following the axial extension of the screw shaft 21 due to thermal expansion, and specifically, they are preferably arranged point-symmetrically or line-symmetrically on a plane perpendicular to the screw shaft 21. The multiple accommodation spaces 66y may also be arranged offset in the axial direction.

[0104] Furthermore, adjacent storage spaces 66y may be communicated with each other via a communication passage as necessary for the purpose of equalizing pressure, etc., and the working fluid inside may circulate through the adjacent storage spaces 66y. For example, in Figures 23(b) and 24, among the adjacent storage spaces 66y, each first space 66A and each second space 66B are communicated with each other via their respective communication passages 66x.

[0105] Furthermore, the support base side member 61 and the bearing housing side member 62 are not limited to being formed as a single member, but may be configured as separate members arranged around the screw shaft 21 according to the layout of the accommodation space 66y. Furthermore, the support base side member 61 and the bearing housing side member 62, which are single members, may also be configured with a portion of the circumferential direction being open or divided so as to be arranged around the screw shaft 21. For example, in Figure 23 (b), two support base side members 61 and two bearing housing side members 62 are configured as separate members in the width direction of the screw shaft 21.

[0106] Furthermore, the recesses and protrusions that form the housing space 66y are not limited to having a circular cross section, but may have any shape such as a rectangle, etc. Furthermore, the cross-sectional dimensions and axial dimensions of the multiple housing spaces 66y can each be configured as desired.

[0107] Even when there are multiple storage spaces 66y in this manner, each storage space 66y is axially divided into a first space 66A and a second space 66B by a partition member 83 arranged in each storage space 66y, and a first pressure generating means of any configuration is stored in a compressed state in the first space 66A, and a second pressure generating means of any configuration is stored in a compressed state in the second space 66B.

[0108] Fifth Embodiment In the housing position adjustment mechanism 60 of the above-described embodiment and modified example, when the screw shaft 21 extends in the axial direction, the volume of the annular space 66 increases, and the compressed disc springs 70 and foam member 90 gradually reduce their pressure while pressing the bearing unit 41 and the bearing housing side member 62 to the left. This causes the pair of angular ball bearings 53 to move axially, maintaining the axial support rigidity of the screw shaft 21.

[0109] However, in the fifth embodiment, the axial support rigidity of the screw shaft 21 is maintained using a housing position adjustment mechanism 60 as shown in FIG. 26 . Specifically, when the screw shaft 21 expands in the axial direction, the bearing unit 41 and the bearing housing side member 62 move to the left via the pair of angular contact ball bearings 53, 53 that move together with the screw shaft 21, and the volume of the annular space 66 decreases. Meanwhile, as the pressure of the multiple disc springs 70 and the foamed member 90 gradually increases, the bearing unit 41 and the bearing housing side member 62 are pressed to the right. Therefore, by adjusting the volume of the annular space 66 and the pressure of the multiple disc springs 70 and the foamed member 90 to allow the screw shaft 21 to expand in the axial direction, the axial support rigidity of the screw shaft 21 can be maintained.

[0110] In this case, the support base side member 61 has a small-diameter cylindrical portion 61c extending from the small-diameter portion of the annular base portion 61b attached to the support base 43 toward the bearing housing 51, and an outward flange portion 61d extending from the tip of the small-diameter cylindrical portion 61c toward the outer diameter side. The bearing housing side member 62 has a large-diameter cylindrical portion 62c extending from the large-diameter portion of the annular base portion 62b attached to the moving-side bearing housing 51 toward the support base 43, and an inward flange portion 62d extending from the tip of the large-diameter cylindrical portion 62c toward the inner diameter side.

[0111] The outward flange portion 61d of the support base side member 61 is relatively movable in the axial direction between the annular base portion 62b and the inward flange portion 62d of the bearing housing side member 62, and its outer peripheral surface is in sliding contact with the inner peripheral surface of the large-diameter cylindrical portion 62c via an O-ring 67. Furthermore, the inward flange portion 62d of the bearing housing side member 62 is relatively movable in the axial direction between the annular base portion 61b and the outward flange portion 61d of the support base side member 61, and its inner peripheral surface is in sliding contact with the outer peripheral surface of the small-diameter cylindrical portion 61c via the O-ring 67. Therefore, the annular space 66 is formed by being partitioned by the small-diameter cylindrical portion 61c and the outward flange portion 61d of the support base side member 61 and the large-diameter cylindrical portion 62c and the inward flange portion 62d of the bearing housing side member 62. This annular space 66 is divided by a partition member 83, with the first space 66A containing multiple disc springs 70 and a first working fluid 80, and the second space 66B containing a foam member 90 and a second working fluid 81.

[0112] Also in this case, in the first and second pressure generating means, even if the temperature rises by more than 4 degrees, when the annular space 66 narrows in the axial direction in accordance with the axial elongation of the screw shaft 21, the spring characteristics, the material of the foam member 90, and the first and second working fluids 80, 81 are appropriately selected so that the desired axial rigidity is imparted to the screw shaft 21 by the pressure acting on the bearing housing side member 62.

[0113] By forming the annular space 66 in this manner, when the screw shaft 21 stretches axially due to thermal expansion, the pair of angular ball bearings 53, 53, the bearing housing 51, and the bearing housing side member 62 move to the left in the figure while compressing the multiple disc springs 70, the foam member 90, and the first and second working fluids 80, 81 within the annular space 66, thereby maintaining the axial support rigidity of the screw shaft 21.

[0114] Further, O-rings 67A are fitted between the inner circumferential surface of the large-diameter cylindrical portion 62c and the outer circumferential surface of the partition wall member 83, and between the outer circumferential surface of the small-diameter cylindrical portion 61c and the inner circumferential surface of the partition wall member 83. Further, O-rings 67 are fitted between the inner circumferential surface of the inward flange portion 62d and the outer circumferential surface of the small-diameter cylindrical portion 61c, and between the outer circumferential surface of the outward flange portion 61d and the inner circumferential surface of the large-diameter cylindrical portion 62c. This prevents leakage of the second working fluid 81 filled in the second space 66B and also functions as a damping mechanism to damp vibrations occurring in the screw shaft 21.

[0115] Furthermore, a first working fluid 80 is stored in the gap between the inner circumferential surface of the inward flange portion 62d and the outer circumferential surface of the small-diameter cylindrical portion 61c, and a second working fluid 81 is stored in the gap between the outer circumferential surface of the outward flange portion 61d and the inner circumferential surface of the large-diameter cylindrical portion 62c. Therefore, the radial pressure of the first and second working fluids 80, 81 acting on the gaps can improve the radial support rigidity and alignment ability between the bearing housing side member 62 and the support base side member 61. As a result, the housing position adjustment mechanism 60 can provide radial support rigidity to the threaded shaft 21 and also have an alignment function for the threaded shaft 21. Note that a similar alignment effect is also provided by the working fluids 80, 81 stored in the gaps between the partition member 83 and the small-diameter cylindrical portion 61c and between the partition member 83 and the large-diameter cylindrical portion 62c.

[0116] The support base side member 61 and the bearing housing side member 62 may each be formed from a single member, but in consideration of ease of assembly, they may each be formed with an O-ring 67 sandwiched between two members 91, 92, 93, 94, as shown in Figure 26. Also, one O-ring 67 and one seal groove 68 are disposed between each opposing surface, but multiple O-rings 67 and multiple seal grooves 68 may be disposed.

[0117] Also, instead of Figure 26, the support base side member 61 may have a large diameter cylindrical portion and an inward flange portion, and the bearing housing side member 62 may have a small diameter cylindrical portion and an outward flange portion, forming an annular space.

[0118] Furthermore, as shown in Figure 27, such a housing position adjustment mechanism 60 may be provided with a storage chamber 71 and an orifice 72 in the outward flange portion 61d, and as in the first embodiment, the second working fluid 81 in the second space 66B and the storage chamber 71 may pass through the orifice 72 and the gap between the inner surface of the large diameter cylindrical portion 62c and the outer surface of the outward flange portion 61d, thereby providing the function of damping vibration of the screw shaft 21.

[0119] The reservoir chamber and the orifice may be formed in the inward flange portion 62d, and the reservoir chamber for storing the first working fluid 80 may be open to the outer peripheral surface of the small-diameter cylindrical portion 61c. In a configuration without an orifice as shown in Figure 26, the damping function of the O-ring 67 can be mainly utilized.

[0120] Also in such a housing position adjustment mechanism 60, the pair of angular contact ball bearings 53, 53 may be arranged in a face-to-face configuration as shown in Figures 26 and 27, or in a back-to-back configuration as shown in Figure 27, or in a parallel configuration or other various support configurations. In addition, although not shown, the pair of angular contact ball bearings does not necessarily have to be made up of two angular contact ball bearings, but can also be made up of three or more ball bearings.

[0121] Furthermore, as shown in Figures 29 and 30, in the housing position adjustment mechanism 60 of the fifth embodiment, as in the second embodiment, the seal groove 68 formed on the inner surface of the inward flange portion 62d and the outer surface of the outward flange portion 61d and the seal groove 68A formed on the outer surface and inner surface of the partition member 83 may be configured by a tapered surface 69a whose groove depth becomes shallower as it moves away from the second space 66B side, and circular axial side surfaces 69b, 69c extending radially from both axial end edges of the tapered surface 69a.

[0122] Therefore, as the pressure of the second working fluid 81 in the second space 66B increases and the O-ring 67 is pressed toward the atmospheric pressure side or the first space 66A side, the O-ring 67 further improves the sealing performance due to the wedge structure between the tapered surfaces 69a of the seal grooves 68, 68A and the outer peripheral surface of the opposing small-diameter cylindrical portion 61c and the inner peripheral surface of the opposing large-diameter cylindrical portion 62c. As a result, even if relative movement occurs between the support base side member 61 and the bearing housing side member 62, leakage of the second working fluid 81 toward the atmospheric pressure side or the first space 66A side can be prevented, and the axial rigidity of the ball screw feed device 20 can be continuously maintained.

[0123] In this modified example, as shown in Figure 29, the seal groove 68 formed on either of the opposing surfaces of the two members 91, 92 that make up the support base side member 61, and the seal groove 68 formed on either of the opposing surfaces of the two members 93, 94 that make up the bearing housing side member 62 may also have a tapered surface 69a whose groove depth becomes shallower as it moves away from the second space side.

[0124] Also, in this modified example, a wear-resistant member may be interposed between the O-ring 67 and at least one of the inner surface of the inward flange portion 62d and the outer surface of the small-diameter cylindrical portion 61c, and between the O-ring 67 and at least one of the outer surface of the outward flange portion 61d and the inner surface of the large-diameter cylindrical portion 62c.

[0125] In this case, the wear-resistant member 59 may be interposed between the O-ring 67 and the opposing surface of the O-ring 67 in a seal groove 68 having a tapered surface 69a as shown in FIG. 29, or may be interposed between the O-ring 67 and the opposing surface of the O-ring 67 in a seal groove 68 having a uniform groove depth as shown in FIG. 21.

[0126] Furthermore, as shown in Figure 31, the housing position adjustment mechanism 60 of the fifth embodiment may be configured so that, similar to the third embodiment, the support base side member 61 and the bearing housing side member 62 are provided with working medium volume change units such as heating elements 130, 131 and cooling media 132, 133.

[0127] As a result, as described in the third embodiment, depending on the state of the ball screw feed device 20 being used, the volume of the foamed material 90 and the first and second working fluids 80, 81 in the first and second spaces 66A, 66B can be expanded by the heating elements 130, 131, or the volume of the foamed material 90 and the first and second working fluids 80, 81 in the first and second spaces 66A, 66B can be contracted by the cooling media 132, 133, thereby maintaining the axial support rigidity in a continuously stable state.

[0128] Furthermore, in the housing position adjustment mechanism 60 of the fifth embodiment, as shown in FIG. 32 , similar to the fourth embodiment, the second support mechanism 40 may have a tandem configuration in which the housing position adjustment mechanism 60 and another housing position adjustment mechanism 160 are arranged in series in the axial direction between the bearing unit 41 and the support base 43.

[0129] In this case, the other support base side member 161 of the other housing position adjustment mechanism 160 has an annular base portion 161b, a small-diameter cylindrical portion 161c, and an outward flange portion 161d, and the other bearing housing side member 162 has an annular base portion 162b, a large-diameter cylindrical portion 162c, and an inward flange portion 162d. The other support base side member 161 and the other bearing housing side member 162 of the other housing position adjustment mechanism 160 are each composed of two members 191, 192, 193, and 194. Furthermore, the support base side member 61 of the housing position adjustment mechanism 60 and the other bearing housing side member 162 of the other housing position adjustment mechanism 160 are connected to each other and configured as a single unit.

[0130] Also, in this embodiment, as in the fourth embodiment, the second support mechanism 40 may be configured such that multiple housing position adjustment mechanisms are arranged in series in the axial direction, or may be configured such that they are arranged in parallel in the radial direction.

[0131] Sixth Embodiment Next, a ball screw feed device according to a sixth embodiment of the present invention will be described with reference to Fig. 33. This embodiment differs from the first embodiment in that the partition member that divides the accommodation space into a first space and a second space is formed by a diaphragm 150.

[0132] Specifically, in this embodiment, steps 64a1, 64b1 are formed on the inward surface 64a and the outward surface 64b of the annular recess 64 so that the radial dimension of the bottom is narrowed. The inner and outer peripheral edges of the ring-shaped diaphragm 150 are positioned and fixed to the steps 64a1, 64b1 of the annular recess 64. The diaphragm 150 has a film structure made of resin, metal, or the like, and its radially central portion is deformable in the axial direction.

[0133] In addition, in this embodiment, the first pressure generating means is a first working fluid (e.g., gas) 80 filled in the first space 66A, and the second pressure generating means is a second working fluid (e.g., hydraulic oil) 81 and a foaming member 90 filled in the second space 66B.

[0134] As a result, the diaphragm 150 deforms in the axial direction due to the pressure in the first space 66A and the second space 66B, and can apply pressure to the bearing housing side member 62 while balancing the pressure in the first space 66A and the second space 66B. Therefore, in this embodiment as well, even if the axial length of the screw shaft 21 changes due to the influence of heat, the axial support rigidity can be continuously maintained in a stable state. The other configurations and operations are the same as those of the first embodiment.

[0135] The present invention is not limited to the above-described embodiments and can be modified, improved, and the like as appropriate. Furthermore, the embodiments and modifications described herein can be combined and applied within a practicable range. For example, in the first to fifth embodiments, the first pressure generating means includes a plurality of disc springs 70 and a first working fluid 80 housed in the first space 66A, and the second pressure generating means includes a foam member 90 and a second working fluid 81 housed in the second space 66B. However, the first pressure generating means and the second pressure generating means are not limited to this. In the present invention, at least one of the first pressure generating means and the second pressure generating means may be configured to include a foam member 90 having a foam core layer 86 and a solid skin layer 87 surrounding the foam core layer 86, and a working fluid 81 filled in the first space or the second space other than the foam member.

[0136] Specifically, in the housing position adjustment mechanism 60 of the first embodiment, as shown in FIG. 34, the first pressure generating means may be a first working fluid (e.g., gas) 80 filled in the first space 66A, and the second pressure generating means may be a second working fluid (e.g., hydraulic oil) 81 and a foaming member 90 filled in the second space 66B.

[0137] Also, as shown in Figure 35, the first pressure generating means may include a cubic foam member 90A and a disc spring 70 housed in the first space 66A, and a first working fluid (e.g., hydraulic oil) 80 filled around the foam member 90A and the disc spring 70, and the second pressure generating means may include a foam member 90 housed in the second space 66B, and a second working fluid (e.g., hydraulic oil) 81 filled around the foam member 90A.

[0138] Furthermore, for example, at least one of the first pressure generating means and the second pressure generating means may be configured to include a foam member 90, an elastic member 70, and a working fluid filled in the first space 66A or the second space 66B other than the foam member 90 and the elastic member 70.

[0139] Alternatively, for example, one of the first pressure generating means and the second pressure generating means may include a foaming member 90 and a working fluid filled in the first space 66A or the second space 66B other than the foaming member 90, and the other of the first pressure generating means and the second pressure generating means may be a working fluid filled in the first space or the second space.

[0140] Furthermore, in addition to these, pressure generating means of other configurations may be arranged in each space 66A, 66B, which are accommodated in a compressed state and can generate pressure to press the bearing unit 41 and the bearing housing side member 62.

[0141] Additionally, as in a modified example of the sixth embodiment shown in FIG. 36 , the first pressure generating means may be a foam member 90 disposed in the first space 66A, and the second pressure generating means may be a working fluid (e.g., hydraulic oil) 81 filled in the second space 66B. In this case, the foam member 90 is disposed throughout the first space 66A and is in contact with the surface of the annular recess 64 and the diaphragm 150. In the example shown in FIG. 36 , the diaphragm 150 is used as a partition member, and the working fluid 81 is prevented from passing through the foam member 90 by the diaphragm 150. Therefore, the foam member 90 may be configured to include a solid skin layer 87 or a cover member that entirely or partially covers the periphery of the foam core layer 86, or may be configured only by the foam core layer 86, as shown in FIG. 36 . That is, in this modified example, the foam member 90 may be configured to include at least a foam core layer.

[0142] In this case as well, the diaphragm 150 is deformed in the axial direction by the pressures in the first space 66A and the second space 66B, and is able to apply pressure to the bearing housing side member 62 while balancing the pressures in the first space 66A and the second space 66B. Therefore, even if the axial length of the screw shaft 21 changes due to the influence of heat, the axial support rigidity can be continuously maintained in a stable state.

[0143] The annular space may also be connected to an auxiliary accumulator or an external pump for supplying hydraulic fluid, if necessary. Furthermore, the annular space may be used to diagnose and correct the condition of the ball screw feed device by monitoring the pressures of the first and second hydraulic fluids and the loads applied to the pair of angular bearings 53, 53.

[0144] In the first to fourth and sixth embodiments, O-rings 67A are fitted between the inward surface 64a of the annular recess 64 and the outer peripheral surface of the partition member 83, and between the outward surface 64b of the annular recess 64 and the inner peripheral surface of the partition member 83. However, this is not a limitation, and any seal members may be arranged to prevent leakage of the first working fluid 80 from within the first space 66A. Similarly, O-rings 67 are fitted between the outward surface 65a of the annular protrusion 65 and the inward surface 64a of the annular recess 64, and between the inward surface 65b of the annular protrusion 65 and the outward surface 64b of the annular recess 64. However, this is not a limitation, and any seal members may be arranged to prevent leakage of the second working fluid 81 from within the second space 66B. In the sixth embodiment, O-rings 67A are also fitted between the inner circumferential surface of the large-diameter cylindrical portion 62c and the outer circumferential surface of the partition wall member 83, and between the outer circumferential surface of the small-diameter cylindrical portion 61c and the inner circumferential surface of the partition wall member 83. However, this is not a limitation and any seal members may be provided to prevent leakage of the first working fluid 80 from the first space 66A. Similarly, O-rings 67 are fitted between the outer circumferential surface of the outward flange portion 61d and the inner circumferential surface of the large-diameter cylindrical portion 62c, and between the inner circumferential surface of the inward flange portion 62d and the outer circumferential surface of the small-diameter cylindrical portion 61c. However, this is not a limitation and any seal members may be provided to prevent leakage of the second working fluid 81 from the second space 66B. Furthermore, it is preferable that the seal members not only prevent leakage of the working fluids 80 and 81 from the first and second spaces 66A and 66B, but also damp vibration of the screw shaft 21, similar to the O-rings 67 and 67A.

[0145] The storage space does not necessarily have to be annular, but may be divided as appropriate. Accordingly, the disc springs and foam members that constitute the pressure generating means may also be divided. In some cases, the disc springs may be formed in a different form, such as a coil spring.

[0146] In any embodiment, the second working fluid 81 needs to be sealed from the outside after being filled in the second space 66B. In this case, for example, in the housing position adjustment mechanism 60 shown in Fig. 2, an oil supply passage 109 for filling the second space 66B with the second working fluid 81 may be formed in the bearing housing side member 62 so as to penetrate radially between the inward surface 64a of the annular recess 64 and the outer peripheral surface of the bearing housing side member 62, as shown in Fig. 37(a).

[0147] A stopper bolt 110 may be attached to the outer peripheral surface of the bearing housing side member 62, threadedly engaging with a female thread portion 109a formed in the oil supply passage 109 to close the oil supply passage 109. Furthermore, the male thread portion of the stopper bolt 110 may be wrapped with sealing tape (not shown) or may be coated or filled with a leak prevention agent, thereby filling the gap between the male thread and the female thread portion 109a, thereby more reliably preventing leakage of the second working fluid 81 filled in a compressed state.

[0148] An annular seal groove 110a may be formed in the surface of the head of the stopper bolt 110 that faces the outer circumferential surface of the bearing housing side member 62. An O-ring 111 may then be attached to the seal groove 110a to improve the sealing performance of the stopper bolt 110. As shown in Figure 37(b), the bottom surface of the seal groove 110a of the stopper bolt 110 may be tapered to further improve the sealing performance.

[0149] Furthermore, the member blocking the oil supply passage 109 may be a stopper plug instead of the stopper bolt 110. For example, the oil supply passage 109 may be blocked by a tapered stopper plug 112 as shown in FIG. 38( a). In this case, the stopper plug 112 is threaded into a female thread portion 109a formed on the outer diameter side of the oil supply passage 109 and fixed to the oil supply passage 109. Furthermore, as shown in FIG. 38( b), the oil supply passage 109 has a tapered female thread portion 109a on the outer diameter side, and a straight portion 109b without a female thread portion is continuous with the female thread portion 109a via a stepped hole 109c. In this case, the stopper plug 112 may be fastened to the female thread portion 109a with a disk-shaped member 113 accommodated in the stepped hole 109c. In this case, the stopper plug 112 is fastened to the female thread portion 109a while deforming the disk-shaped member 113, thereby ensuring a tight seal between the contact surface of the disk-shaped member 113 and the stepped hole 109c. In addition, the male thread portion of the stopper plug 112 may also be wrapped with sealing tape (not shown) or coated or filled with a leak prevention agent to fill the gap between the male thread and the female thread portion 109a, thereby providing a good seal.

[0150] As shown in Fig. 38(c), the disk-shaped member 113 may be integrated with an elastically deformable member 114 that forms the contact surface with the stepped hole 109c. Alternatively, as shown in Fig. 38(d), the disk-shaped member 113 may have an annular seal groove 113a formed in the contact surface with the stepped hole 109c, and an O-ring 115 may be disposed therein.

[0151] Furthermore, the oil supply passage 109 communicating with the second space 66B is not limited to a configuration in which it is formed so as to penetrate radially, but may be formed so as to penetrate axially through any of the members that constitute the second space 66B.

[0152] Furthermore, the support base may be configured to directly or indirectly support the support base side member of the housing position adjustment mechanism, and is not limited to a configuration in which the rotation axis passes through it as in the above embodiment, but may also be configured to be arranged around the rotation axis, and can be designed into any shape.

[0153] (Application to Other Ball Screw Feeding Devices) In the ball screw feeding device 20 of Fig. 1, the drive motor 12 is coupled to one side (the right side in Fig. 1) of the screw shaft 21 supported by the first support mechanism 30, but the present invention is not limited to this. That is, as in the ball screw feeding device 20 of Fig. 39, the drive motor 12 may be coupled to the other side (the left side in Fig. 39) of the screw shaft 21 supported by the second support mechanism 40. In this case, the drive motor 12 is fixed to the base 1 and supported by another support base 85 through which the screw shaft 21 passes. In addition, the tip of the small diameter shaft portion 27 is disposed within the coupling 28 away from the rotating shaft 12a of the drive motor 12 so that the small diameter shaft portion 27 can move in the axial direction when the screw shaft 21 expands axially due to thermal expansion.

[0154] Therefore, the present invention can be used with a high degree of freedom as a ball screw feed device for positioning devices that perform high-precision processing and measurement, such as machine tools (machining centers, lathes, grinding machines, etc.), measuring machines (three-dimensional measuring devices), semiconductor manufacturing equipment (tables for exposure devices, inspection probes, etc.), inspection equipment, etc., and for use in semiconductor manufacturing, etc.

[0155] Furthermore, in the above embodiment, the support base 43 is disposed on the axial center side relative to the bearing unit 41, but the present invention is not limited to this, and the support base 43 may be disposed on the axial end side relative to the bearing unit 41. That is, the support base 43 may be disposed on the axial center side relative to the bearing unit 41 or on the axial end side depending on the configuration and function of the housing position adjustment mechanism 60.

[0156] 40 and 41 , the support base 43 is provided closer to the axial end than the bearing unit 41. In this case, the support base side member 61 may be attached directly or indirectly to the support base 43, and the bearing housing side member 62 may be attached directly or indirectly to the bearing housing 51. In addition, the spacer 48a, which is disposed between the inner ring 55 and the fastening nut 38b, passes through the through hole 43a of the support base 43 and the inside of the support base side member 61 and the bearing housing side member 62.

[0157] 42 and 43, the support base 43 is disposed closer to the axial end than the bearing unit 41, and is fixed to a support base side member 61 disposed closer to the axial center than the bearing unit 41 by an outer cylinder portion 43b that extends axially from a main body portion having a through hole 43a and surrounds the periphery of the housing position adjustment mechanism 60. In this case as well, the support base side member 61 may be attached directly or indirectly to the support base 43, and the bearing housing side member 62 may be attached directly or indirectly to the bearing housing 51. In addition, a spacer 48a disposed between the inner ring 55 and the fastening nut 38b passes through the through hole 43a of the support base 43.

[0158] (Applications Other Than Ball Screw Feeder Devices) Although the above-described embodiment describes a ball screw feeder device, the present invention can also be applied to a rotation support device in which both axial ends of a rotating shaft are rotatably supported by a pair of support mechanisms. That is, when the axial length of the rotating shaft changes due to the influence of heat, a configuration can be made in which the axial support rigidity of the rotating shaft is continuously and stably maintained using a housing position adjustment mechanism such as that of the above embodiment. Furthermore, by using the housing position adjustment mechanism of the above embodiment, vibrations in the axial direction can be damped.

[0159] 44, a rotation support device 120 includes a rotating shaft 121 and a pair of support mechanisms 30, 40 that rotatably support both axial ends of the rotating shaft 121. The support mechanism 30 includes a bearing housing 31 fixed to the base 1, and bearings 33, 33 that rotatably support the rotating shaft 121 relative to the bearing housing 31, i.e., a pair of angular contact ball bearings 33, 33 arranged in a face-to-face combination.

[0160] The support mechanism 40 also includes a bearing housing 51, a bearing unit 41 that supports the rotating shaft 121 rotatably relative to the bearing housing 51 and is equipped with bearings 53, 53 that can support axial loads, i.e., a pair of angular ball bearings 53, 53 arranged in a face-to-face combination, a support base 43 that is arranged axially toward the center of the bearing unit 41 and through which the rotating shaft 121 passes, and a housing position adjustment mechanism 60 that is arranged between the bearing unit 41 and the support base 43.

[0161] The housing position adjustment mechanism 60 includes a support base side member 61 provided on the support base 43 side and through which the rotating shaft 121 passes, a bearing housing side member 62 provided on the bearing housing 51 side and through which the rotating shaft 121 passes and which is axially movable relative to the support base side member 61, a partition member 83 disposed in an accommodation space formed between the support base side member 61 and the bearing housing side member 62 and dividing the accommodation space into a first space 66A and a second space 66B in the axial direction, a first pressure generating means (a plurality of disc springs 70 and a first working fluid 80 in the figure) accommodated in a compressed state in the first space 66A, and a second pressure generating means (a foam member 90 and a second working fluid 81 in the figure) accommodated in a compressed state in the second space 66B. Note that in Figure 44, components denoted with the same reference numerals as those in the above embodiment are considered to be substantially the same, and descriptions thereof will be omitted or simplified. In addition, the various structures described in relation to the ball screw feed device 20 can also be applied to the rotation support device, and similar effects can be achieved.

[0162] Furthermore, the bearings 33, 53 of the support mechanisms 30, 40 of the rotation support device 120 may be angular contact ball bearings as in the above embodiment, but are not limited to these and may be roller bearings or plain bearings capable of supporting axial loads. By using such bearings capable of supporting axial loads, the first and second pressure generating means can be compressed via the bearings, particularly in the support mechanism 40, by tightening the fastening nut 38b as in the above embodiment.

[0163] In addition, in Figure 44, the second support mechanism 40 having the housing position adjustment mechanism 60 is configured to support the end of the rotating shaft 121, but as shown in Figure 45, the second support mechanism 40 having the housing position adjustment mechanism 60 may also be configured to support the rotating shaft 121 at a position closer to another support base 85 that supports the drive motor 12.

[0164] For example, when a rotary support device 120 such as that shown in FIG. 45 is applied to a spindle device that rotates a tool in a machine tool, by attaching a tool to the end of the rotating shaft 121 supported by the support mechanism 30, the axial support rigidity of the rotating shaft 121 is continuously and stably maintained while the axial positioning of the tool is reliably performed, thereby enabling high-precision machining.

[0165] In the rotary support device 120 shown in Figures 44 and 45, the drive motor 12 does not necessarily have to be arranged coaxially with the rotating shaft 121, and the power of the drive motor may be transmitted to the rotating shaft 121 via, for example, a pulley or a gear train.

[0166] In addition, the drive motor 12 is not necessarily limited to a separate motor arranged coaxially with the rotary shaft 121, and may be, for example, a built-in motor directly configured on the rotary shaft 121. Furthermore, the rotation support device 120 may be a housing case in which the bearing housing 31 of the first support mechanism 30 and the support base 43 of the second support mechanism 40 are integrated as a support body.

[0167] In addition, in a rotation support device other than a ball screw feed device, the support base may be disposed on the axial end side of the bearing unit as shown in FIGS.

[0168] Furthermore, in the above embodiment, the housing position adjustment mechanism is described as a mechanism for adjusting the axial position of the bearing housing of the bearing that supports the rotating shaft, but the present invention is not limited to this and can be applied as a support mechanism position adjustment mechanism for a shaft support device. That is, the shaft is not limited to a rotating shaft, and the support mechanism is not limited to a configuration including a bearing. The shaft support device may be configured to include a shaft and a pair of support mechanisms provided at both axial ends of the shaft to support the shaft, one of the pair of support mechanisms including a support body (e.g., support base 43 in the above embodiment) through which the shaft passes or around which the shaft is disposed.

[0169] Therefore, the support mechanism position adjustment mechanism of the shaft support device may include a first member (e.g., support base member 61 in the above embodiment) provided on one of the shaft side and the support side, through which the shaft passes or which can be arranged around the shaft, a second member (e.g., bearing housing member 62 in the above embodiment) provided on the other of the shaft side and the support side, through which the shaft passes or which can be arranged around the shaft, movable axially relative to the first member, and which forms an accommodation space (e.g., annular space 66 in the above embodiment) between the first member and the second member, a partition member disposed in the accommodation space and dividing the accommodation space into a first space and a second space in the axial direction, a first pressure generating means accommodated in the first space in a compressed state, and a second pressure generating means accommodated in the second space in a compressed state. The support mechanism position adjustment mechanism of such a shaft support device can be configured to employ the structure of the housing position adjustment mechanism described in connection with the ball screw feed device 20, and achieves similar effects.

[0170] 46 and 47 show a rigid-jointed structure 200 as a shaft support device in which a support mechanism position adjustment mechanism is provided on one of a pair of support mechanisms that support a shaft. The rigid-jointed structure 200 includes two parallel steel supports 231, 243 that are fixed vertically to a base 1. Concentric through-holes 231a, 243a are formed in the supports 231, 243, and a shaft 221 that constitutes a beam member is inserted through these through-holes. The supports 231, 243 may be pillars, beams, support plates, or the like, and may be made of any material and shape that can support a shaft.

[0171] In this example, the flange portion 226 on one axial end of the shaft 221 abuts against the small diameter step portion 231b of the through hole 231a of the support body 231, and one end of the shaft 221 is positioned and fixed to the support body 231 by the other support mechanism that attaches the pressing lid 232 to the large diameter step portion 231c of the through hole 231a.

[0172] The other axial end of shaft 221 passes through a through-hole 243a of support 243, protrudes to the opposite side from support 231, and is supported by support 243 via a shaft guide member 250, a housing 251, and a support mechanism position adjustment mechanism 260, which constitute one of the support mechanisms. The cross-sectional shape of the central part of shaft 221 is arbitrary, and may be made of a square steel pipe, an H-shaped steel, or the like.

[0173] The shaft guide member 250 is a member configured to surround the shaft 221, guides the small diameter portion 225 of the shaft 221, and has both outer diameter ends sandwiched and integrated between the housing 251 and a pressing member 247 fixed to the housing 251.

[0174] As in the above embodiment, the housing 251 is attached to the support body 243 via a support mechanism position adjustment mechanism 260. That is, a first member 261 corresponding to the support base side member 61 in the above embodiment is fitted into a through hole 243a of the support body 243 and fixed to the support body 243, and a second member 262 corresponding to the bearing housing side member 62 in the above embodiment is fitted into an inward flange 251a of the housing 251 and fixed to the housing 251.

[0175] Therefore, when the shaft guide member 250 is tightened by the fastening nut 38b that is threaded onto the male screw 225a via the spacer 48, a reaction force acts on the shaft guide member 250, and the shaft guide member 250 is subjected to an axial load. Therefore, a predetermined rigidity is provided between the supports 231, 243 and the shaft 221.

[0176] Furthermore, in such a rigid-jointed structure 200, even if axial elongation occurs in the shaft 221, the support mechanism position adjustment mechanism 260 operates to move the shaft guide member 250 and the housing 251 in the same direction in response to the axial elongation of the shaft 221. Therefore, the axial force acting on the shaft 221 can be maintained, and the rigidity of the rigid-jointed structure 200 can be maintained.

[0177] In this example, the housing 251 and the second member 262 of the support mechanism position adjustment mechanism 260 may be integrally configured, and the shaft guide member 250 may be disposed on the integrated member. Alternatively, the housing 251 may be omitted, and the shaft guide member 250 may be directly fixed to the second member 262 of the support mechanism position adjustment mechanism 260. The shaft support device is not limited to a rigid joint structure as in this example, and may have a brace structure in which the support mechanisms on the shaft side and the support body side are pin-jointed. In this case, the shaft 221 may be disposed at an angle depending on the configuration of the brace structure. Furthermore, in a shaft support device such as a rigid structure, both support mechanisms may have a support mechanism position adjustment mechanism.

[0178] As described above, the present specification discloses the following: (1) A rotary support device comprising a rotating shaft and a pair of support mechanisms rotatably supporting both axial ends of the rotating shaft, one of the pair of support mechanisms comprising: a bearing unit comprising a bearing housing and a bearing that rotatably supports the rotating shaft relative to the bearing housing and is capable of supporting an axial load; a support base through which the rotating shaft passes or is arranged around the rotating shaft; and a housing position adjustment mechanism disposed between the bearing unit and the support base, wherein the housing position adjustment mechanism comprises: a support base side member provided on the support base side and through which the rotating shaft passes or is arranged around the rotating shaft; a bearing housing side member provided on the bearing housing side and through which the rotating shaft passes or is arranged around the rotating shaft, and is movable axially relative to the support base side member; a partition member disposed in an accommodation space formed between the support base side member and the bearing housing side member and dividing the accommodation space into a first space and a second space in the axial direction; and a first pressure generating means accommodated in a compressed state in the first space. a second pressure generating means accommodated in a compressed state in the second space, wherein at least one of the first pressure generating means and the second pressure generating means comprises a foam member having a foam core layer and at least one of a solid skin layer and a cover member covering the periphery of the foam core layer, and a working fluid filled in the first space or the second space other than the foam member. With this configuration, axial support rigidity can be continuously and stably maintained even if the axial length of the rotating shaft changes due to the influence of heat. Furthermore, the two types of pressure generating means accommodated in the accommodation space can impart the support rigidity and damping characteristics required for the rotation support device.

[0179] (2) The rotation support device according to (1), wherein at least one of the first pressure generating means and the second pressure generating means comprises the foamed member, an elastic member, and the working fluid filled in the first space or the second space other than the foamed member and the elastic member. With this configuration, pressure can be applied to the bearing housing member by the foamed member, the elastic member, and the working fluid, and axial support rigidity can be continuously and stably maintained even if the axial length of the rotating shaft changes due to the influence of heat.

[0180] (3) The rotation support device according to (1), wherein either the first pressure generating means or the second pressure generating means comprises the foamed material and the working fluid other than the foamed material that fills the first space or the second space, and the other of the first pressure generating means or the second pressure generating means is the working fluid that fills the first space or the second space. With this configuration, either the first pressure generating means or the second pressure generating means can apply pressure to the bearing housing member by using the foamed material and the working fluid, and the other can apply pressure by using the working fluid, and the axial support rigidity can be continuously and stably maintained even if the axial length of the rotating shaft changes due to the influence of heat.

[0181] (4) The rotation support device according to (1), wherein at least one of the first pressure generating means and the second pressure generating means includes a plurality of the foam members. With this configuration, the total pressure generated by the plurality of foam members can continuously and stably maintain the support rigidity in the axial direction even if the axial length of the rotating shaft changes due to the influence of heat.

[0182] (5) The rotation support device according to (1), wherein one of the support base member and the bearing housing member has an annular recess that opens to one axial side, the other of the support base member and the bearing housing member has an annular protrusion that protrudes toward the other axial side and is fitted axially slidably within the annular recess, and the partition member is disposed in an accommodation space formed between the annular recess and the annular protrusion and is formed in an annular shape so as to be in sliding contact with the inward and outward surfaces of the annular recess. With this configuration, the space that accommodates the two pressure generating means can be configured compactly around the rotation shaft.

[0183] (6) The rotation support device according to (5), wherein at least one seal member is attached between the inward surface of the annular recess and the outer peripheral surface of the partition member, and between the outward surface of the annular recess and the inner peripheral surface of the partition member, and at least one seal member is attached between the inward surface of the annular recess and the outward surface of the annular protrusion, and between the outward surface of the annular recess and the inward surface of the annular protrusion. With this configuration, when a working fluid is filled in the space, the seal member can prevent leakage of the working fluid, and the function of the housing position adjustment mechanism can be maintained for a long period of time.

[0184] (7) The rotation support device according to (5) or (6), wherein a working fluid is stored in each gap between the inward surface of the annular recess and the outer peripheral surface of the partition member, between the outward surface of the annular recess and the inner peripheral surface of the partition member, between the inward surface of the annular recess and the outward surface of the annular protrusion, and between the outward surface of the annular recess and the inward surface of the annular protrusion. With this configuration, the housing position adjustment mechanism can provide radial support rigidity to the rotating shaft and can also have an alignment function with respect to the rotating shaft.

[0185] (8) The rotation support device according to (5) or (6), wherein the housing position adjustment mechanism includes: a reservoir chamber formed in the annular convex portion so as to open to an outward or inward surface of the annular convex portion and configured to store a working fluid; and an orifice formed in the annular convex portion so as to communicate the reservoir chamber with the second space. With this configuration, the working fluid in the second space and the reservoir chamber passes through the orifice and the gap between the circumferential surface of the annular convex portion and the circumferential surface of the annular concave portion, thereby damping the vibration.

[0186] (9) The rotation support device according to (8), wherein the second pressure generating means includes the working fluid stored in a compressed state in the second space, the storage chamber, and the orifice, and the foaming member stored in the storage chamber. With this configuration, the foaming member can also be stored in the storage chamber, thereby increasing the degree of freedom in layout.

[0187] (10) The rotation support device according to (5) or (6), wherein the tip surface of the annular convex portion is formed in a convex or concave tapered shape from its inner peripheral edge to its outer peripheral edge. This configuration can further improve the aligning function and coaxiality of the angular contact ball bearing with respect to the rotating shaft, and can also improve the axial load characteristics of the rotating shaft.

[0188] (11) The rotation support device according to (6), wherein the seal member is an O-ring, the second space is filled with at least the working fluid, and a seal groove in which the O-ring is disposed is formed on the inward surface of the annular recess or the outward surface of the annular protrusion, and on the outward surface of the annular recess or the inward surface of the annular protrusion, respectively, and the seal groove has a tapered surface whose groove depth decreases with increasing distance from the accommodation space. With this configuration, by using an O-ring as the seal member, the O-ring also functions as a damping mechanism to damp vibrations occurring in the rotating shaft. Furthermore, even when relative movement occurs between the support base side member and the bearing housing side member, leakage of the working fluid to the atmospheric pressure side can be prevented, thereby continuously maintaining the axial rigidity of the rotation support device.

[0189] (12) The rotation support device according to (6) or (11), wherein the sealing member is an O-ring, and a wear-resistant member is interposed between the O-ring and at least one of the inward surface of the annular recess and the outward surface of the annular protrusion, and between the O-ring and at least one of the outward surface of the annular recess and the inward surface of the annular protrusion. According to this configuration, by using the O-ring as the sealing member, the O-ring also functions as a damping mechanism, damping vibrations generated in the rotating shaft. Furthermore, stress concentration on the O-ring can be dispersed, suppressing damage such as wear to the O-ring and the contact surface with the O-ring.

[0190] (13) The rotation support device according to (5), wherein the partition member is a ring-shaped diaphragm attached to the inward surface of the annular recess and the outward surface of the annular recess, and the radial center portion of the partition member is deformable in the axial direction. With this configuration, pressure can be applied to the bearing housing member while balancing the pressures in the first space and the second space, and the axial support rigidity can be continuously maintained in a stable state even if the axial length of the rotating shaft changes.

[0191] (14) The rotation support device according to (1), wherein one of the support base member and the bearing housing member has a small-diameter cylindrical portion extending toward one axial direction and an outward flange portion extending from a tip of the small-diameter cylindrical portion toward an outer diameter side, and the other of the support base member and the bearing housing member has a large-diameter cylindrical portion extending toward the other axial direction and having an inner circumferential surface against which the outer circumferential surface of the outward flange portion slides, and an inward flange portion extending from a tip of the large-diameter cylindrical portion toward an inner diameter side and having an inner circumferential surface that slides against the outer circumferential surface of the small-diameter cylindrical portion, and the accommodation space is formed by the small-diameter cylindrical portion, the outward flange portion, the large-diameter cylindrical portion, and the inward flange portion. With this configuration, axial support rigidity can be continuously and stably maintained even if the axial length of the rotating shaft changes due to the influence of heat.

[0192] (15) The rotation support device according to (14), wherein at least one seal member is fitted between the inner circumferential surface of the large-diameter cylindrical portion and the outer circumferential surface of the partition member, and between the outer circumferential surface of the small-diameter cylindrical portion and the inner circumferential surface of the partition member, and at least one seal member is fitted between the inner circumferential surface of the inward flange portion and the outer circumferential surface of the small-diameter cylindrical portion, and between the outer circumferential surface of the outward flange portion and the inner circumferential surface of the large-diameter cylindrical portion. With this configuration, when the space is filled with working fluid, the seal members can prevent leakage of the working fluid, and the function of the housing position adjustment mechanism can be maintained for a long period of time.

[0193] (16) The rotation support device according to (14) or (15), wherein a working fluid is stored in each gap between the inner circumferential surface of the large-diameter cylindrical portion and the outer circumferential surface of the partition member, between the outer circumferential surface of the small-diameter cylindrical portion and the inner circumferential surface of the partition member, between the inner circumferential surface of the inward flange portion and the outer circumferential surface of the small-diameter cylindrical portion, and between the outer circumferential surface of the outward flange portion and the inner circumferential surface of the large-diameter cylindrical portion. With this configuration, the housing position adjustment mechanism can provide radial support rigidity to the rotating shaft and can also have an alignment function with respect to the rotating shaft.

[0194] (17) The rotation support device according to (14) or (15), wherein the housing position adjustment mechanism includes: a reservoir chamber formed in the outward flange portion or the inward flange portion so as to open to an inner circumferential surface of the large-diameter cylindrical portion or an outer circumferential surface of the small-diameter cylindrical portion, for storing a working fluid; and an orifice formed in the outward flange portion or the inward flange portion so as to communicate the reservoir chamber with the second space. With this configuration, the working fluid in the second space and the reservoir chamber passes through the orifice and a gap between the inner circumferential surface of the large-diameter cylindrical portion and the outer circumferential surface of the outward flange portion, or between the outer circumferential surface of the small-diameter cylindrical portion and the inner circumferential surface of the inward flange portion, thereby damping the vibration.

[0195] (18) The rotation support device according to (15), wherein the seal member is an O-ring, the second space is filled with at least the working fluid, and the inner circumferential surface of the inward flange portion or the outer circumferential surface of the small-diameter cylindrical portion and the outer circumferential surface of the outward flange portion or the inner circumferential surface of the large-diameter cylindrical portion are formed with seal grooves in which the O-rings are disposed, respectively, and the seal grooves have tapered surfaces whose depths become shallower with increasing distance from the accommodation space. With this configuration, by using an O-ring as the seal member, the O-ring also functions as a damping mechanism to damp vibrations occurring in the rotating shaft. Furthermore, even when relative movement occurs between the support base member and the bearing housing member, leakage of the working fluid to the atmospheric pressure side can be prevented, thereby continuously maintaining the axial rigidity of the rotation support device.

[0196] (19) The rotation support device according to (15), wherein the sealing member is an O-ring, and a wear-resistant member is interposed between the O-ring and at least one of the inner circumferential surface of the inward flange portion and the outer circumferential surface of the small-diameter cylindrical portion, and between the O-ring and at least one of the outer circumferential surface of the outward flange portion and the inner circumferential surface of the large-diameter cylindrical portion. With this configuration, the O-ring serves as a damping mechanism to attenuate vibrations occurring in the rotating shaft. Furthermore, stress concentration on the O-ring can be dispersed, suppressing damage such as wear to the O-ring and the contact surface with the O-ring.

[0197] (20) The rotation support device according to (1), wherein one of the support base member and the bearing housing member has an annular recess that opens to one axial side, and the other of the support base member and the bearing housing member has an annular protrusion that protrudes toward the other axial side and is slidably fitted within the annular recess in the axial direction, and the partition member is disposed in an accommodation space formed between the annular recess and the annular protrusion, is attached to the inward and outward surfaces of the annular recess, and is formed into an annular shape, and is deformable by the first pressure generating means and the second pressure generating means. With this configuration, it is possible to continuously maintain a stable axial support rigidity even if the axial length of the rotating shaft changes due to the influence of heat.

[0198] (21) The rotation support device according to (1), wherein a working medium volume change unit is attached to at least one of the support base side member and the bearing housing side member, and changes the volume of at least one of the first pressure generating means and the second pressure generating means by heating or cooling at least one of the first pressure generating means and the second pressure generating means. With this configuration, the first pressure generating means or the second pressure generating means can be heated or cooled to expand or contract the volume of the working medium, thereby continuously maintaining stable support rigidity in the axial direction.

[0199] (22) The rotation support device according to (1), wherein one of the pair of support mechanisms further includes another housing position adjustment mechanism disposed adjacent to the housing position adjustment mechanism between the bearing unit and the support base, the other housing position adjustment mechanism including: another support base side member provided on the support base side and through which the rotation shaft passes or which is arranged around the rotation shaft, another bearing housing side member provided on the bearing housing side and through which the rotation shaft passes or which is arranged around the rotation shaft and which is movable in the axial direction relative to the other support base side member, and a third pressure generating means accommodated in a compressed state in another accommodation space formed between the other support base side member and the other bearing housing side member. With this configuration, it is even easier to maintain the axial rigidity of the rotation support device.

[0200] (23) The rotation support device according to (1), wherein one of the support base member and the bearing housing member has a plurality of recesses that open to one axial side, and the other of the support base member and the bearing housing member has a plurality of protrusions that protrude toward the other axial side and are axially slidably fitted into the plurality of recesses, and the plurality of accommodation spaces are respectively formed between the plurality of recesses and the plurality of protrusions. With this configuration, the layout of the housing position adjustment mechanism can be freely configured using the plurality of accommodation spaces.

[0201] (24) The rotation support device according to (23), wherein the plurality of accommodation spaces are arranged on both sides of the rotation shaft in the width direction. With this configuration, the height dimension of the housing position adjustment mechanism can be reduced.

[0202] (25) The rotation support device according to (23), wherein the partition members are disposed in the plurality of accommodation spaces respectively and are formed so as to be in sliding contact with the inner surfaces of the respective recesses. With this configuration, the plurality of accommodation spaces can be configured in common.

[0203] (26) The rotation support device according to any one of (1) to (25), wherein the bearing of the bearing unit includes a pair of angular contact ball bearings each including an outer ring fitted inside the bearing housing, an inner ring fitted externally onto an axial end of the rotating shaft, and balls disposed so as to roll between the outer ring and the inner ring. With this configuration, when the bearing unit has a pair of angular contact ball bearings, it is possible to continuously and stably maintain axial support rigidity even if the axial length of the rotating shaft changes due to the influence of heat.

[0204] (27) The rotation support device according to any one of (1) to (26), which is a ball screw feed device, further comprising: a screw shaft having a helical thread groove formed on its outer circumferential surface; a nut having a helical thread groove formed on its inner circumferential surface; and a plurality of balls rollably disposed between the thread groove of the screw shaft and the thread groove of the nut. With this configuration, a ball screw feed device can be configured that can continuously and stably maintain axial support rigidity even if the axial length of the rotation shaft changes due to the influence of heat.

[0205] (28) A support mechanism position adjustment mechanism for a shaft support device provided on one of the pair of support mechanisms in a shaft support device including a shaft and a pair of support mechanisms provided at both axial ends of the shaft to support the shaft, comprising: one of the pair of support mechanisms having a support through which the shaft passes or which is arranged around the shaft; a first member provided on one of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis; a second member provided on the other of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis, movable axially relative to the first member, and which forms an accommodation space between itself and the first member; a partition member provided in the accommodation space, which divides the accommodation space into a first space and a second space in the axial direction; a first pressure generating means accommodated in the first space in a compressed state; and a second pressure generating means accommodated in the second space in a compressed state. A support mechanism position adjustment mechanism for a shaft support device, wherein at least one of the first pressure generating means and the second pressure generating means comprises a foam member having a foam core layer and at least one of a solid skin layer and a cover member surrounding the foam core layer, and a working fluid filled in the first space or the second space other than the foam member. With this configuration, axial support rigidity can be continuously and stably maintained even if the axial length of the shaft changes due to the influence of heat. Furthermore, the two types of pressure generating means housed in the housing space can impart the support rigidity and damping characteristics required for the shaft support device.

[0206] (29) The support mechanism position adjustment mechanism for a shaft support device described in (28), wherein the shaft is a rotating shaft, one of the pair of support mechanisms further includes a bearing unit including a bearing housing and a bearing that rotatably supports the rotating shaft relative to the bearing housing and is capable of supporting an axial load, the support mechanism position adjustment mechanism is a housing position adjustment mechanism disposed between the bearing unit and the support, the first member is a support side member provided on the support side and through which the rotating shaft can pass or which can be arranged around the rotating shaft, and the second member is a bearing housing side member provided on the bearing housing side and through which the rotating shaft can pass or which can be arranged around the rotating shaft, movable in the axial direction relative to the support side member, and which forms the accommodation space between itself and the support side member. With this configuration, it is possible to continuously and stably maintain axial support rigidity even if the axial length of the shaft changes due to the influence of heat.

[0207] (30) The support mechanism position adjustment mechanism for a shaft support device according to (28) or (29), wherein at least one of the first pressure generating means and the second pressure generating means comprises the foam member, an elastic member, and the working fluid filled in the first space or the second space other than the foam member and the elastic member. With this configuration, pressure can be applied to the first member or the second member by the foam member, the elastic member, and the working fluid, and axial support rigidity can be continuously and stably maintained even if the axial length of the shaft changes due to the influence of heat.

[0208] (31) The support mechanism position adjustment mechanism for a shaft support device described in (28) or (29), wherein either the first pressure generating means or the second pressure generating means comprises the foam member and the working fluid other than the foam member that is filled in the first space or the second space, and the other of the first pressure generating means or the second pressure generating means is the working fluid that is filled in the first space or the second space. With this configuration, either the first pressure generating means or the second pressure generating means can apply pressure to the first member or the second member by the foam member and the working fluid, and the other can apply pressure by the working fluid, and the axial support rigidity can be continuously and stably maintained even if the axial length of the shaft changes due to the influence of heat.

[0209] (32) The support mechanism position adjustment mechanism for a shaft support device according to (28) or (29), wherein at least one of the first pressure generating means and the second pressure generating means comprises a plurality of the foam members. With this configuration, the total pressure generated by the plurality of foam members can continuously and stably maintain axial support rigidity even if the axial length of the shaft changes due to the influence of heat.

[0210] (33) The support mechanism position adjustment mechanism for a shaft support device according to (28) or (29), wherein one of the first member and the second member has an annular recessed portion that opens to one axial side, the other of the first member and the second member has an annular protruding portion that protrudes toward the other axial side and is fitted slidably in the axial direction within the annular recessed portion, and the partition member is disposed in an accommodation space formed between the annular recessed portion and the annular protruding portion and is formed in an annular shape so as to be in sliding contact with the inward and outward surfaces of the annular recessed portion. With this configuration, the space that accommodates the two pressure generating means can be configured compactly around the shaft.

[0211] (34) The support mechanism position adjustment mechanism for a shaft support device according to (33), wherein at least one seal member is fitted between the inward surface of the annular recess and the outer peripheral surface of the partition member and between the outward surface of the annular recess and the inner peripheral surface of the partition member, and at least one seal member is fitted between the inward surface of the annular recess and the outward surface of the annular protrusion and between the outward surface of the annular recess and the inward surface of the annular protrusion. With this configuration, when a working fluid is filled in the space, the seal member can prevent leakage of the working fluid, and the function of the support mechanism position adjustment mechanism can be maintained for a long period of time.

[0212] (35) A support mechanism position adjustment mechanism for a shaft support device according to (33) or (34), wherein a working fluid is stored in each gap between the inward surface of the annular recess and the outer peripheral surface of the partition member, between the outward surface of the annular recess and the inner peripheral surface of the partition member, between the inward surface of the annular recess and the outward surface of the annular protrusion, and between the outward surface of the annular recess and the inward surface of the annular protrusion. With this configuration, the support mechanism position adjustment mechanism can provide radial support rigidity to the shaft and can also have an aligning function with respect to the shaft.

[0213] (36) The support mechanism position adjustment mechanism for a shaft support device according to (33) or (34), wherein the support mechanism position adjustment mechanism comprises: a reservoir chamber formed in the annular convex portion so as to open to an outward or inward surface of the annular convex portion and configured to store a working fluid; and an orifice formed in the annular convex portion so as to communicate the reservoir chamber with the second space. With this configuration, the working fluid in the second space and the reservoir chamber passes through the orifice and the gap between the circumferential surface of the annular convex portion and the circumferential surface of the annular concave portion, thereby damping the vibration.

[0214] (37) The support mechanism position adjustment mechanism for a shaft support device according to (36), wherein the second pressure generating means comprises: the working fluid stored in a compressed state in the second space, the storage chamber, and the orifice; and the foamed member stored in the storage chamber. With this configuration, the foamed member can also be stored in the storage chamber, thereby increasing the degree of freedom in layout.

[0215] (38) The support mechanism position adjustment mechanism for a shaft support device according to (33) or (34), wherein the tip surface of the annular convex portion is formed in a convex tapered or concave tapered shape from its inner peripheral edge to its outer peripheral edge. With this configuration, it is possible to further improve the shaft alignment function and coaxiality, and also to improve the axial load characteristics of the shaft.

[0216] (39) The support mechanism position adjustment mechanism for a shaft support device described in (34), wherein the seal member is an O-ring, the second space is filled with at least the working fluid, and a seal groove in which the O-ring is disposed is formed on the inward surface of the annular recess or the outward surface of the annular protrusion, and on the outward surface of the annular recess or the inward surface of the annular protrusion, respectively, and the seal groove has a tapered surface whose groove depth decreases with increasing distance from the accommodation space. With this configuration, by using an O-ring as the seal member, the O-ring also functions as a damping mechanism to damp vibrations occurring in the shaft. Furthermore, even when relative movement occurs between the first member and the second member, leakage of the working fluid to the atmospheric pressure side can be prevented, thereby continuously maintaining the axial rigidity of the shaft support device.

[0217] (40) The support mechanism position adjustment mechanism for a shaft support device according to (34) or (39), wherein the sealing member is an O-ring, and a wear-resistant member is interposed between the O-ring and at least one of the inward surface of the annular recess and the outward surface of the annular protrusion, and between the O-ring and at least one of the outward surface of the annular recess and the inward surface of the annular protrusion. With this configuration, by using an O-ring as the sealing member, the O-ring also functions as a damping mechanism, damping vibrations occurring in the shaft. Furthermore, stress concentration on the O-ring can be dispersed, suppressing damage such as wear to the O-ring and the contact surface with the O-ring.

[0218] (41) The support mechanism position adjustment mechanism for a shaft support device according to (33), wherein the partition member is a ring-shaped diaphragm attached to the inward surface of the annular recess and the outward surface of the annular recess, and the radial center portion of the partition member is deformable in the axial direction. With this configuration, pressure can be applied to the second member while balancing the pressures in the first space and the second space, and the axial support rigidity can be continuously maintained in a stable state even if the axial length of the shaft changes.

[0219] (42) The support mechanism position adjustment mechanism for a shaft support device described in (28), wherein one of the first member and the second member has a small-diameter cylindrical portion extending toward one side in the axial direction and an outward flange portion extending from a tip of the small-diameter cylindrical portion toward an outer diameter side, and the other of the first member and the second member has a large-diameter cylindrical portion extending toward the other side in the axial direction and having an inner circumferential surface with which the outer circumferential surface of the outward flange portion slides, and an inward flange portion extending from the tip of the large-diameter cylindrical portion toward an inner diameter side and having an inner circumferential surface that slides against the outer circumferential surface of the small-diameter cylindrical portion, and the accommodation space is formed by the small-diameter cylindrical portion, the outward flange portion, the large-diameter cylindrical portion, and the inward flange portion. With this configuration, it is possible to continuously and stably maintain axial support rigidity even if the axial length of the shaft changes due to the influence of heat.

[0220] (43) A support mechanism position adjustment mechanism for a shaft support device according to (42), wherein at least one seal member is fitted between the inner peripheral surface of the large-diameter cylindrical portion and the outer peripheral surface of the partition member and between the outer peripheral surface of the small-diameter cylindrical portion and the inner peripheral surface of the partition member, and at least one seal member is fitted between the inner peripheral surface of the inward flange portion and the outer peripheral surface of the small-diameter cylindrical portion and between the outer peripheral surface of the outward flange portion and the inner peripheral surface of the large-diameter cylindrical portion. With this configuration, when a working fluid is filled in the space, the seal member can prevent leakage of the working fluid, and the function of the support mechanism position adjustment mechanism can be maintained for a long period of time.

[0221] (44) A support mechanism position adjustment mechanism for a shaft support device according to (42) or (43), wherein a working fluid is stored in each gap between the inner peripheral surface of the large-diameter cylindrical portion and the outer peripheral surface of the partition member, between the outer peripheral surface of the small-diameter cylindrical portion and the inner peripheral surface of the partition member, between the inner peripheral surface of the inward flange portion and the outer peripheral surface of the small-diameter cylindrical portion, and between the outer peripheral surface of the outward flange portion and the inner peripheral surface of the large-diameter cylindrical portion. With this configuration, the support mechanism position adjustment mechanism can provide radial support rigidity to the shaft and can also have an aligning function with respect to the shaft.

[0222] (45) The support mechanism position adjustment mechanism for a shaft support device according to (42) or (43), wherein the support mechanism position adjustment mechanism comprises: a reservoir chamber formed in the outward flange portion or the inward flange portion so as to open to the inner circumferential surface of the large-diameter cylindrical portion or the outer circumferential surface of the small-diameter cylindrical portion, for storing a working fluid; and an orifice formed in the outward flange portion or the inward flange portion so as to communicate the reservoir chamber with the second space. With this configuration, the working fluid in the second space and the reservoir chamber passes through the orifice and a gap between the inner circumferential surface of the large-diameter cylindrical portion and the outer circumferential surface of the outward flange portion, or between the outer circumferential surface of the small-diameter cylindrical portion and the inner circumferential surface of the inward flange portion, thereby damping the vibration.

[0223] (46) The support mechanism position adjustment mechanism for a shaft support device according to (43), wherein the seal member is an O-ring, the second space is filled with at least the working fluid, and a seal groove in which the O-ring is disposed is formed on the inner circumferential surface of the inward flange portion or the outer circumferential surface of the small-diameter cylindrical portion, and on the outer circumferential surface of the outward flange portion or the inner circumferential surface of the large-diameter cylindrical portion, and the seal groove has a tapered surface whose groove depth decreases with increasing distance from the accommodation space. With this configuration, by using an O-ring as the seal member, the O-ring also functions as a damping mechanism to damp vibrations occurring in the shaft. Furthermore, even when relative movement occurs between the first member and the second member, leakage of the working fluid to the atmospheric pressure side can be prevented, thereby continuously maintaining the axial rigidity of the shaft support device.

[0224] (47) The support mechanism position adjustment mechanism for a shaft support device according to (43), wherein the sealing member is an O-ring, and a wear-resistant member is interposed between the O-ring and at least one of the inner circumferential surface of the inward flange portion and the outer circumferential surface of the small-diameter cylindrical portion, and between the O-ring and at least one of the outer circumferential surface of the outward flange portion and the inner circumferential surface of the large-diameter cylindrical portion. With this configuration, by using an O-ring as the sealing member, the O-ring also functions as a damping mechanism, damping vibrations occurring in the shaft. Furthermore, stress concentration on the O-ring can be dispersed, suppressing damage such as wear to the O-ring and the contact surface with the O-ring.

[0225] (48) The support mechanism position adjustment mechanism for a shaft support device according to (28) or (29), wherein one of the first member and the second member has an annular recessed portion that opens to one axial side, and the other of the first member and the second member has an annular protruding portion that protrudes toward the other axial side and is slidably fitted within the annular recessed portion in the axial direction, and the partition member is disposed in an accommodation space formed between the annular recessed portion and the annular protruding portion, is attached to the inward and outward surfaces of the annular recessed portion, and is formed in an annular shape, and is deformable by the first pressure generating means and the second pressure generating means. With this configuration, the axial support rigidity can be continuously maintained in a stable state even if the axial length of the shaft changes due to the influence of heat.

[0226] (49) A support mechanism position adjustment mechanism for a shaft support device according to any one of (28) to (36), wherein a working medium volume change unit that changes the volume of at least one of the first pressure generating means and the second pressure generating means by heating or cooling at least one of the first pressure generating means and the second pressure generating means is attached to at least one of the first member and the second member. According to this configuration, the axial support rigidity can be continuously maintained in a stable state by heating or cooling the first pressure generating means or the second pressure generating means to expand or contract the volume of the working medium.

[0227] (50) A support mechanism position adjustment mechanism for a shaft support device according to any of (28) to (49), wherein one of the pair of support mechanisms further includes an other support mechanism position adjustment mechanism disposed adjacent to the support mechanism position adjustment mechanism between the bearing unit and the support base, the other support mechanism position adjustment mechanism including: an other first member provided on the support base side and through which the shaft passes or which is disposed around the axis, an other second member provided on the bearing housing side and through which the shaft passes or which is disposed around the axis and which is movable in the axial direction relative to the other first member, and a third pressure generating means accommodated in a compressed state in another accommodation space formed between the other first member and the other second member. With this configuration, it is even easier to maintain the axial rigidity of the shaft support device.

[0228] (51) A support mechanism position adjustment mechanism for a shaft support device according to (28), wherein one of the first member and the second member has a plurality of recesses that open to one axial side, and the other of the first member and the second member has a plurality of protrusions that protrude toward the other axial side and are fitted slidably in the axial direction within the plurality of recesses, and the plurality of accommodation spaces are formed between the plurality of recesses and the plurality of protrusions, respectively. With this configuration, the layout of the support mechanism position adjustment mechanism can be freely configured using the plurality of accommodation spaces.

[0229] (52) The support mechanism position adjustment mechanism for a shaft support device according to (51), wherein the plurality of accommodation spaces are arranged on both sides of the shaft in the width direction. With this configuration, the height dimension of the support mechanism position adjustment mechanism can be reduced.

[0230] (53) The support mechanism position adjustment mechanism for a shaft support device according to (51), wherein the partition members are disposed in the plurality of accommodation spaces respectively and are formed so as to be in sliding contact with the inner surfaces of the respective recesses. With this configuration, the plurality of accommodation spaces can be configured in common.

[0231] (54) A rotary support device comprising a rotating shaft and a pair of support mechanisms rotatably supporting both axial ends of the rotating shaft, one of the pair of support mechanisms comprising: a bearing unit comprising a bearing housing and a bearing rotatably supporting the rotating shaft relative to the bearing housing and capable of supporting an axial load; a support base through which the rotating shaft passes or which is arranged around the rotating shaft; and a housing position adjustment mechanism arranged between the bearing unit and the support base, wherein the housing position adjustment mechanism comprises: a support base side member provided on the support base side and through which the rotating shaft passes or which is arranged around the rotating shaft; a bearing housing side member provided on the bearing housing side and through which the rotating shaft passes or which is arranged around the rotating shaft and is movable axially relative to the support base side member; a partition member provided in an accommodation space formed between the support base side member and the bearing housing side member and which divides the accommodation space into a first space and a second space in the axial direction; and a first pressure generating means accommodated in a compressed state in the first space. a second pressure generating means accommodated in the second space in a compressed state, wherein one of the first pressure generating means and the second pressure generating means is a foam member having at least a foam core layer, and the other of the first pressure generating means and the second pressure generating means is a working fluid filled in the first space or the second space. With this configuration, even if the axial length of the rotating shaft changes due to the influence of heat, the axial support rigidity can be continuously and stably maintained. Furthermore, the two types of pressure generating means accommodated in the accommodation space can impart the support rigidity and damping characteristics required for the rotation support device.

[0232] (55) A support mechanism position adjustment mechanism for a shaft support device provided on one of the pair of support mechanisms in a shaft support device including a shaft and a pair of support mechanisms provided at both axial ends of the shaft to support the shaft, comprising: one of the pair of support mechanisms having a support through which the shaft passes or which is arranged around the shaft; a first member provided on one of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis; a second member provided on the other of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis, movable axially relative to the first member, and which forms an accommodation space between itself and the first member; a partition member provided in the accommodation space, which divides the accommodation space into a first space and a second space in the axial direction; a first pressure generating means accommodated in the first space in a compressed state; and a second pressure generating means accommodated in the second space in a compressed state. A support mechanism position adjustment mechanism for a shaft support device, wherein one of the first pressure generating means and the second pressure generating means is a foam member having at least a foam core layer, and the other of the first pressure generating means and the second pressure generating means is a working fluid filled in the first space or the second space. With this configuration, axial support rigidity can be continuously and stably maintained even if the axial length of the shaft changes due to the influence of heat. Furthermore, the two types of pressure generating means housed in the housing space can impart the support rigidity and damping characteristics required for the shaft support device.

[0233] This application is based on a Japanese patent application (Patent Application No. 2024-72742) filed on April 26, 2024, the contents of which are incorporated herein by reference.

[0234] DESCRIPTION OF SYMBOLS 20 Ball screw feed device (shaft support device, rotation support device) 21 Screw shaft (shaft, rotating shaft) 23 Nut 30 First support mechanism (support mechanism) 31 Fixed side bearing housing 33, 53 Angular contact ball bearing (bearing) 34, 54 Outer ring 35, 55 Inner ring 36, 56 Balls 38a, 38b Fastening nut 40 Second support mechanism (support mechanism) 41 Bearing unit 43 Support base (support body) 51 Moving side bearing housing (bearing housing) 51a Inward flange 59 Wear-resistant member 60 Housing position adjustment mechanism (support mechanism position adjustment mechanism) 61 Support base side member (first member) 62 Bearing housing side member (second member) 64 Annular recess 65 Annular protrusion 66 Annular space (accommodation space) 66A First space 66B Second space 67, 67A O-ring (sealing member) 68 Seal groove 69a Tapered surface 70 Disc spring (elastic member) 80 First working fluid 81 Second working fluid 83 Partition member 86 Foamed core layer 87 Solid skin layer 90 Foamed member 100 Hollow member 120 Rotation support device 121 Rotating shaft 130, 131 Heat generating element (working medium volume changing unit) 132, 133 Cooling medium (working medium volume changing unit) 160 Other housing position adjusting mechanism (other support mechanism position adjusting mechanism) 161 Other support base side member (other support body side member) 162 Other bearing housing side member

Claims

1. A rotary support device comprising a rotating shaft and a pair of support mechanisms rotatably supporting both axial ends of the rotating shaft, one of the pair of support mechanisms comprising: a bearing unit comprising a bearing housing and a bearing that rotatably supports the rotating shaft relative to the bearing housing and is capable of supporting an axial load; a support base through which the rotating shaft passes or is arranged around the rotating shaft; and a housing position adjustment mechanism disposed between the bearing unit and the support base, wherein the housing position adjustment mechanism comprises: a support base side member provided on the support base side and through which the rotating shaft passes or is arranged around the rotating shaft; a bearing housing side member provided on the bearing housing side and through which the rotating shaft passes or is arranged around the rotating shaft, and which is movable axially relative to the support base side member; a partition member disposed in an accommodation space formed between the support base side member and the bearing housing side member and dividing the accommodation space into a first space and a second space in the axial direction; and a first pressure generating means accommodated in a compressed state in the first space. a second pressure generating means accommodated in a compressed state in the second space, wherein at least one of the first pressure generating means and the second pressure generating means comprises a foam member having a foam core layer, and at least one of a solid skin layer and a cover member covering the periphery of the foam core layer, and a working fluid filled in the first space or the second space other than the foam member.

2. A rotation support device as described in claim 1, wherein at least one of the first pressure generating means and the second pressure generating means comprises the foamed member, an elastic member, and the working fluid filled in the first space or the second space other than the foamed member and the elastic member.

3. A rotation support device as described in claim 1, wherein one of the first pressure generating means and the second pressure generating means comprises the foaming material and the working fluid filled in the first space or the second space other than the foaming material, and the other of the first pressure generating means and the second pressure generating means is the working fluid filled in the first space or the second space.

4. The rotation support device according to claim 1, wherein at least one of the first pressure generating means and the second pressure generating means comprises a plurality of the foam members.

5. A rotational support device as described in claim 1, wherein one of the support base side member and the bearing housing side member has an annular recess that opens to one axial side, the other of the support base side member and the bearing housing side member has an annular protrusion that protrudes toward the other axial side and fits axially within the annular recess, and the partition member is disposed in an accommodating space formed between the annular recess and the annular protrusion, and is formed in an annular shape so as to slide against the inward and outward surfaces of the annular recess.

6. A rotation support device as described in claim 5, wherein at least one seal member is fitted between the inward surface of the annular recess and the outer peripheral surface of the partition member, and between the outward surface of the annular recess and the inner peripheral surface of the partition member, and at least one seal member is fitted between the inward surface of the annular recess and the outward surface of the annular protrusion, and between the outward surface of the annular recess and the inward surface of the annular protrusion.

7. A rotation support device as described in claim 5 or 6, wherein a working fluid is stored in each gap between the inward surface of the annular recess and the outer peripheral surface of the partition member, between the outward surface of the annular recess and the inward surface of the partition member, between the inward surface of the annular recess and the outward surface of the annular protrusion, and between the outward surface of the annular recess and the inward surface of the annular protrusion.

8. A rotary support device as described in claim 5 or 6, wherein the housing position adjustment mechanism comprises: a reservoir chamber formed within the annular convex portion so as to open to the outward or inward surface of the annular convex portion and for storing a working fluid; and an orifice formed within the annular convex portion so as to communicate the reservoir chamber with the second space.

9. A rotation support device as described in claim 8, wherein the second pressure generating means comprises: the working fluid stored in a compressed state in the second space, the storage chamber, and the orifice; and the foam member stored in the storage chamber.

10. A rotary support device according to claim 5 or 6, wherein the tip surface of the annular convex portion is formed in a convex or concave tapered shape from its inner peripheral edge to its outer peripheral edge.

11. A rotation support device as described in claim 6, wherein the sealing member is an O-ring, the second space is filled with at least the working fluid, a seal groove in which the O-ring is disposed is formed on the inward surface of the annular recess or the outward surface of the annular protrusion, and on the outward surface of the annular recess or the inward surface of the annular protrusion, respectively, and the seal groove has a tapered surface whose groove depth becomes shallower as it moves away from the storage space side.

12. A rotation support device as described in claim 6, wherein the sealing member is an O-ring, and a wear-resistant member is interposed between the O-ring and at least one of the inward-facing surface of the annular recess and the outward-facing surface of the annular protrusion, and between the O-ring and at least one of the outward-facing surface of the annular recess and the inward-facing surface of the annular protrusion.

13. A rotary support device according to claim 5, wherein the partition member is attached to the inward surface of the annular recess and the outward surface of the annular recess, and the radial center portion thereof is a ring-shaped diaphragm that is deformable in the axial direction.

14. A rotational support device as described in claim 1, wherein one of the support base side member and the bearing housing side member has a small-diameter cylindrical portion extending to one axial side and an outward flange portion extending from the tip of the small-diameter cylindrical portion toward the outer diameter side, and the other of the support base side member and the bearing housing side member has a large-diameter cylindrical portion extending to the other axial side and having an inner circumferential surface with which the outer circumferential surface of the outward flange portion slides, and an inward flange portion extending from the tip of the large-diameter cylindrical portion toward the inner diameter side and having an inner circumferential surface that slides against the outer circumferential surface of the small-diameter cylindrical portion, and the storage space is formed by the small-diameter cylindrical portion, the outward flange portion, the large-diameter cylindrical portion, and the inward flange portion.

15. A rotation support device as described in claim 14, wherein at least one seal member is respectively fitted between the inner peripheral surface of the large diameter cylindrical portion and the outer peripheral surface of the partition member, and between the outer peripheral surface of the small diameter cylindrical portion and the inner peripheral surface of the partition member, and at least one seal member is respectively fitted between the inner peripheral surface of the inward flange portion and the outer peripheral surface of the small diameter cylindrical portion, and between the outer peripheral surface of the outward flange portion and the inner peripheral surface of the large diameter cylindrical portion.

16. A rotation support device as described in claim 14 or 15, wherein a working fluid is stored in each gap between the inner surface of the large diameter cylindrical portion and the outer surface of the partition member, between the outer surface of the small diameter cylindrical portion and the inner surface of the partition member, between the inner surface of the inward flange portion and the outer surface of the small diameter cylindrical portion, and between the outer surface of the outward flange portion and the inner surface of the large diameter cylindrical portion.

17. A rotational support device as described in claim 14 or 15, wherein the housing position adjustment mechanism comprises: a storage chamber formed within the outward flange portion or the inward flange portion so as to open onto the inner surface of the large diameter cylindrical portion or the outer surface of the small diameter cylindrical portion, for storing a working fluid; and an orifice formed within the outward flange portion or the inward flange portion so as to communicate the storage chamber with the second space.

18. A rotary support device as described in claim 15, wherein the sealing member is an O-ring, the second space is filled with at least the working fluid, and a seal groove in which the O-ring is disposed is formed on the inner surface of the inward flange portion or the outer surface of the small diameter cylindrical portion, and on the outer surface of the outward flange portion or the inner surface of the large diameter cylindrical portion, and the seal groove has a tapered surface whose groove depth becomes shallower as it moves away from the storage space side.

19. A rotation support device as described in claim 15, wherein the sealing member is an O-ring, and a wear-resistant member is interposed between the O-ring and at least one of the inner peripheral surface of the inward flange portion and the outer peripheral surface of the small-diameter cylindrical portion, and between the O-ring and at least one of the outer peripheral surface of the outward flange portion and the inner peripheral surface of the large-diameter cylindrical portion.

20. A rotary support device as described in claim 1, wherein one of the support base side member and the bearing housing side member has an annular recess that opens to one axial side, and the other of the support base side member and the bearing housing side member has an annular protrusion that protrudes toward the other axial side and fits axially within the annular recess so as to be slidable therein, and the partition member is disposed in an accommodating space formed between the annular recess and the annular protrusion, is attached to the inward and outward surfaces of the annular recess, and is formed in an annular shape, and is deformable by the first pressure generating means and the second pressure generating means.

21. A rotary support device as described in claim 1, wherein a working medium volume change unit is attached to at least one of the support base side member and the bearing housing side member, which changes the volume of at least one of the first pressure generating means and the second pressure generating means by heating or cooling at least one of the first pressure generating means and the second pressure generating means.

22. A rotary support device as described in claim 1, wherein one of the pair of support mechanisms further comprises another housing position adjustment mechanism arranged adjacent to the housing position adjustment mechanism between the bearing unit and the support base, and the other housing position adjustment mechanism comprises: another support base side member provided on the support base side and through which the rotation shaft passes or which is arranged around the rotation shaft; another bearing housing side member provided on the bearing housing side and through which the rotation shaft passes or which is arranged around the rotation shaft and which is movable axially relative to the other support base side member; and a third pressure generating means accommodated in a compressed state in another accommodation space formed between the other support base side member and the other bearing housing side member.

23. A rotary support device as described in claim 1, wherein one of the support base side member and the bearing housing side member has a plurality of recesses opening to one axial side, and the other of the support base side member and the bearing housing side member has a plurality of protrusions protruding toward the other axial side and fitting axially slidably within the plurality of recesses, and wherein the plurality of storage spaces are formed between the plurality of recesses and the plurality of protrusions, respectively.

24. A rotary support device according to claim 23, wherein the plurality of storage spaces are arranged on both sides of the rotary shaft in the width direction.

25. A rotation support device according to claim 23, wherein the partition members are arranged in the respective storage spaces and are formed so as to be in sliding contact with the inner surfaces of the respective recesses.

26. A rotary support device as described in claim 1, wherein the bearing of the bearing unit includes a pair of angular contact ball bearings each having an outer ring fitted inside the bearing housing, an inner ring fitted outside the axial end of the rotating shaft, and balls arranged freely rollable between the outer ring and the inner ring.

27. The rotary support device according to claim 1, which is a ball screw feed device, further comprising: a rotating shaft which is a screw shaft having a helical thread groove formed on its outer circumferential surface; a nut having a helical thread groove formed on its inner circumferential surface; and a plurality of balls arranged so as to roll freely between the thread groove of the screw shaft and the thread groove of the nut.

28. A support mechanism position adjustment mechanism for a shaft support device provided on one of the pair of support mechanisms in a shaft support device comprising a shaft and a pair of support mechanisms provided at both axial ends of the shaft for supporting the shaft, the support mechanism position adjustment mechanism being provided on one of the pair of support mechanisms, wherein one of the pair of support mechanisms has a support through which the shaft passes or which is arranged around the shaft; a first member provided on one of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis; a second member provided on the other of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis, movable axially relative to the first member, and which forms an accommodation space between itself and the first member; a partition member provided within the accommodation space, which divides the accommodation space into a first space and a second space in the axial direction; a first pressure generating means accommodated in the first space in a compressed state; and a second pressure generating means accommodated in the second space in a compressed state. A support mechanism position adjustment mechanism for a shaft support device, wherein at least one of the first pressure generating means and the second pressure generating means comprises a foam member having a foam core layer, and at least one of a solid skin layer and a cover member covering the periphery of the foam core layer, and a working fluid filled in the first space or the second space other than the foam member.

29. A support mechanism position adjustment mechanism for a shaft support device as described in claim 28, wherein the shaft is a rotating shaft, one of the pair of support mechanisms further comprises a bearing unit including a bearing housing and a bearing that rotatably supports the rotating shaft relative to the bearing housing and is capable of supporting an axial load, the support mechanism position adjustment mechanism is a housing position adjustment mechanism arranged between the bearing unit and the support, the first member is a support side member provided on the support side and through which the rotating shaft can pass or which can be arranged around the rotating shaft, and the second member is a bearing housing side member provided on the bearing housing side and through which the rotating shaft can pass or which can be arranged around the rotating shaft, which is movable axially relative to the support side member and forms the accommodation space between itself and the support side member.

30. A rotary support device comprising a rotating shaft and a pair of support mechanisms rotatably supporting both axial ends of the rotating shaft, one of the pair of support mechanisms comprising: a bearing unit comprising a bearing housing and a bearing that rotatably supports the rotating shaft relative to the bearing housing and is capable of supporting an axial load; a support base through which the rotating shaft passes or is arranged around the rotating shaft; and a housing position adjustment mechanism disposed between the bearing unit and the support base, wherein the housing position adjustment mechanism comprises: a support base side member provided on the support base side and through which the rotating shaft passes or is arranged around the rotating shaft; a bearing housing side member provided on the bearing housing side and through which the rotating shaft passes or is arranged around the rotating shaft and is movable axially relative to the support base side member; a partition member disposed in an accommodation space formed between the support base side member and the bearing housing side member and dividing the accommodation space into a first space and a second space in the axial direction; and a first pressure generating means accommodated in a compressed state in the first space. a second pressure generating means accommodated in the second space in a compressed state, wherein one of the first pressure generating means and the second pressure generating means is a foam member having at least a foam core layer, and the other of the first pressure generating means and the second pressure generating means is a working fluid filled in the first space or the second space.

31. A support mechanism position adjustment mechanism for a shaft support device provided on one of the pair of support mechanisms in a shaft support device comprising a shaft and a pair of support mechanisms provided at both axial ends of the shaft for supporting the shaft, the support mechanism position adjustment mechanism being provided on one of the pair of support mechanisms, wherein one of the pair of support mechanisms has a support through which the shaft passes or which is arranged around the shaft, the support mechanism comprising: a first member provided on one of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis; a second member provided on the other of the shaft side and the support side, through which the shaft can pass or which can be arranged around the axis, movable axially relative to the first member, and which forms an accommodation space between itself and the first member; a partition member provided within the accommodation space, which divides the accommodation space into a first space and a second space in the axial direction; a first pressure generating means accommodated in the first space in a compressed state; and a second pressure generating means accommodated in the second space in a compressed state. A support mechanism position adjustment mechanism for a shaft support device, wherein one of the first pressure generating means and the second pressure generating means is a foam member having at least a foam core layer, and the other of the first pressure generating means and the second pressure generating means is a working fluid filled in the first space or the second space.

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