JP2014223705A - Rotary shaft device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary shaft device capable of further reducing the influence of thermal displacement.SOLUTION: A rotary shaft device includes a rotary shaft 16, a housing 15 which surrounds an outer circumferential surface of the rotary shaft 16 and a plurality of bearings 31, 32 which are arranged between the rotary shaft 16 and the housing 15, rotatably support the rotary shaft 16 for the housing 15 and are respectively arranged on different positions in the shaft direction. A plurality of cooling channels 61, 62 which circulate cooling liquid respectively independently toward the circumferential direction on the outside in the shaft orthogonal direction of the rotary shaft 16 are formed on positions different in the shaft direction. The plurality of cooling channels 61, 62 are formed over all the range ΔZ in the shaft direction from the position of the bearing 31 arranged on one edge side in the shaft direction of the plurality of bearings 31, 32 to the position of the bearing 32 arranged on the other edge side in the shaft direction and are cooled over all of the range ΔZ in the shaft direction on the housing 15 by the cooling liquid circulated through the plurality of cooling channels 61, 62.

Description

  The present invention relates to a rotary shaft device.

  In machine tools and the like, a structure is cooled because thermal displacement of the structure affects machining accuracy. In particular, main shaft devices such as machining centers, lathes, and grinding machines, and rotary shaft devices such as grinding wheel shaft devices of a grinding machine have a large amount of heat generation, and various cooling methods have been applied so far.

  For example, in Japanese Utility Model Laid-Open No. 5-342 (Patent Document 1), a spiral coolant flow path is formed on the outer peripheral side of the motor portion in the housing, and the spiral coolant flow is formed on the outer peripheral side of the bearing portion in the housing. The formation of a path is described. Japanese Patent Laying-Open No. 2003-56582 (Patent Document 2) describes that a coolant channel is formed in a housing and a coolant channel is formed along the center of a rotating shaft.

Japanese Utility Model Publication No. 5-342 JP 2003-56582 A

  In order to perform processing with higher accuracy, it is necessary to further reduce the influence of thermal displacement, and there is still room for improvement over conventional cooling methods. For example, when the cooling flow paths are formed at two different locations in the axial direction as in the cooling method of Patent Document 1, the heat generated from the bearings and the motor may move outward from the axial center of the housing. is there. If it does so, the axial direction center part of a housing will carry out a thermal displacement, and also there exists a possibility that another member heat-transferred from the said part of a housing may carry out a thermal displacement.

  This invention is made | formed in view of such a situation, and it aims at providing the rotating shaft apparatus which can further reduce the influence of a thermal displacement.

(Claim 1) A rotating shaft device according to the present means is disposed between a rotating shaft, a housing surrounding an outer peripheral surface of the rotating shaft, the rotating shaft and the housing, and the rotating shaft with respect to the housing. And a plurality of bearings disposed at different positions in the axial direction.
In the housing, a plurality of cooling passages are formed at different positions in the axial direction to independently flow the cooling liquid in the circumferential direction outside the axis orthogonal direction of the rotating shaft. The plurality of cooling flow paths are formed over the entire range in the axial direction from the position of the bearing disposed on one axial end side of the plurality of bearings to the position of the bearing disposed on the other axial end side. Is done. The cooling liquid flowing through the plurality of cooling channels cools the entire range in the axial direction of the housing.

  In the rotary shaft device according to the present means, the plurality of cooling flow paths are axially extending from the position of the bearing disposed on one axial end side of the plurality of bearings to the position of the bearing disposed on the other axial end side. It is formed over the entire range (hereinafter referred to as “the entire range between the bearings”). As a result, the cooling liquid flowing through the plurality of cooling channels cools the entire range between the bearings in the housing.

  Here, the heat source in the rotary shaft device includes the bearing itself. Therefore, heat is transmitted from the bearings on both sides between the plurality of bearings in the housing. That is, it is also required to suppress thermal displacement between a plurality of bearings that are heat sources. Therefore, as described above, the housing is uniformly cooled in the entire range between the bearings, so that the thermal displacement of the entire range between the bearings of the housing can be reduced. In particular, since the cooling flow path is also formed in the axial center portion of the housing, the movement of heat can be reliably stopped. Therefore, as a result, the thermal displacement in the part can be reduced. Naturally, heat transfer from the housing to another member can also be suppressed, and thermal displacement of the other member can be suppressed.

  Furthermore, in the rotating shaft device according to the present means, the plurality of cooling channels are independently formed at different positions in the axial direction. Here, “independent” means that the characteristics of the coolant flowing through each cooling flow path can be made different, and the supply source for supplying the cooling liquid to each cooling flow path is common. Does not prevent you from doing. The characteristics of the coolant include, for example, the coolant flow rate and the coolant temperature.

  That is, the cooling capacity of each of the plurality of cooling channels can be varied. Here, in the rotary shaft device, the plurality of bearings, which are one of the heat sources, generally have different heat generation amounts. Therefore, by forming a plurality of cooling channels independently, it is possible to exhibit a cooling capacity corresponding to the amount of heat generated at each axial position. Therefore, by performing cooling according to the heat generation amount at the axial position of the housing, the difference in thermal displacement in the entire range between the bearings of the housing can be reduced.

  Thus, the rotary shaft device according to the present means can uniformly cool the entire range between the bearings of the housing, and can adjust the cooling capacity according to the respective axial positions, thereby reducing the influence of the thermal displacement of the housing. . And when the said rotating shaft apparatus is applied to a machine tool, a processing precision can further be improved.

Below, the suitable aspect of the rotating shaft apparatus which concerns on this means is demonstrated.
(Claim 2) Preferably, each of the plurality of cooling channels formed in the housing is configured by a plurality of branch channels arranged at equal intervals, and one of the cooling channels adjacent in the axial direction is The separation distance between the branch flow path on one end side in the axial direction constituting the cooling flow path and the branch flow path on the other end side in the axial direction constituting the other cooling flow path is a plurality of tributaries constituting the respective cooling flow paths. Equal to the road separation distance. Thereby, even if the cooling capacity is adjusted according to the respective axial positions, the entire range between the bearings of the housing can be reliably and uniformly cooled.

  (Claim 3) Preferably, at least one of the plurality of bearings is a fluid bearing, and the housing is formed with a reservoir for storing a bearing fluid discharged from the fluid bearing, The plurality of cooling channels are formed so as to surround the rotating shaft and the pool portion from the outside in the direction perpendicular to the axis.

  When a fluid bearing is applied, the bearing fluid generates heat. Since the bearing fluid is usually recovered, there is a risk that the portion of the housing through which the heated bearing fluid flows is thermally displaced. Particularly, the reservoir portion of the housing that stores the bearing fluid is greatly affected by the heat of the generated bearing fluid. Therefore, by forming a plurality of cooling channels so as to surround the rotating shaft and the reservoir from the outside in the direction perpendicular to the axis, the periphery of the rotating shaft and the periphery of the reservoir can be reliably cooled. Thereby, the influence of the thermal displacement can be reliably reduced in the entire range between the bearings of the housing.

(Claim 4) Preferably, a discharge flow path for circulating the bearing fluid from the pool portion to the tank is formed in the housing, and the plurality of cooling flow paths include the rotating shaft, the pool portion, and the pool portion. The discharge channel is formed so as to surround from the outside in the direction perpendicular to the axis.
Furthermore, the influence of heat transfer from the discharge channel can be reduced by forming a plurality of cooling channels so as to surround the discharge channel from the reservoir to the tank from the outside in the direction perpendicular to the axis.

  (5) Preferably, the rotary shaft device is at least one of a temperature of the housing, a temperature of the rotary shaft, a thermal displacement of the housing, and a thermal displacement of the rotary shaft at each of different positions in the axial direction. A plurality of detectors that detect one of the plurality of detectors, and a coolant control device that controls the characteristics of the coolant flowing through each of the plurality of cooling channels based on the detection values of each of the plurality of detectors. .

  By controlling the characteristics of the coolant flowing through each of the plurality of cooling flow paths in accordance with the detection values of each of the plurality of detectors, the difference in thermal displacement in the entire range between the bearings of the housing can be reduced. Here, the characteristics of the coolant include the flow rate of the coolant and the temperature of the coolant as described above.

  (Claim 6) Preferably, a rotating tool is attached to one end of the rotating shaft in the axial direction, and a belt for transmitting the rotational force of the output shaft of the rotary drive device is attached to the other axial end of the rotating shaft. Among the plurality of bearings, a load according to processing by the rotary tool mainly acts on the bearing disposed on the rotary tool side, and among the plurality of bearings, the bearing disposed on the belt side The load according to the tension by the belt mainly acts.

  With this configuration, the amount of heat generated by each bearing is different. Therefore, by forming the plurality of cooling channels in the housing in the configuration, the difference in thermal displacement in the entire range between the bearings of the housing can be reduced.

It is a top view of the grinding machine in the embodiment of the present invention. It is an enlarged view of the right side surface about the wheel head and the member on a wheel head in the grinding machine of FIG. 1st embodiment: III-III sectional drawing of FIG. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. However, the motor is not shown in cross section. The same applies below. It is VI-VI sectional drawing of FIG. It is a perspective view of the cooling flow path provided in the grindstone stand of FIG. 2nd embodiment: III-III sectional drawing of FIG. It is IX-IX sectional drawing of FIG. It is XX sectional drawing of FIG.

Below, the grinder which applied the rotating shaft apparatus based on this invention is demonstrated. Here, the grindstone shaft device of the grinding machine in this embodiment constitutes a rotary shaft device.
<First embodiment>
(1. Outline configuration of grinding machine)
A grinding wheel traverse type cylindrical grinder will be described as an example of the grinder of this embodiment. However, for example, a table traverse type grinding machine can be applied to the grinding machine according to the present invention.

  A schematic configuration of the grinding machine will be described with reference to FIG. The grinding machine 1 is configured as follows. A bed 11 is fixed on the floor, and a spindle 12 and a tailstock device 13 are attached to the bed 11 to rotatably support the workpiece W at both ends. Further, a traverse base 14 that is movable in the Z-axis direction is provided on the bed 11. On the traverse base 14, a grindstone base 15 that is movable in the X-axis direction is provided.

  A rotating shaft 16 is rotatably supported on the grindstone table 15 (corresponding to the “housing” of the present invention). A grinding wheel 17 (corresponding to the “rotating tool” of the present invention) is attached to one end of the rotating shaft 16 in the axial direction. That is, the grinding wheel 17 can rotate with respect to the grinding wheel base 15. On the grindstone platform 15, a drive motor 18 (corresponding to the “rotation drive device” of the present invention) is arranged behind the rotation shaft 16 in the X-axis direction (upper side in FIG. 1). Here, with reference to the grindstone platform 15, the workpiece W side is referred to as the X-axis front, and the side opposite to the workpiece W is referred to as the X-axis rear.

  A belt 19 that transmits the rotational force of the output shaft 18 a of the drive motor 18 to the rotary shaft 16 is suspended between the output shaft 18 a of the drive motor 18 and the other axial end of the rotary shaft 16. That is, the rotating shaft 16 and the grinding wheel 17 can be rotated with respect to the grinding wheel base 15 by the rotational force of the drive motor 18. Further, the grindstone table 15 is provided with a grindstone cover 20 that covers a portion other than the vicinity of the grinding point where the workpiece W in the grinding wheel 17 is ground. Further, the bed 11 is provided with a sizing device 21 for measuring the diameter of the workpiece W. Further, the grinding machine 1 is provided with a control device 22 that rotates the spindle 12 and the grinding wheel 17 and controls the position of the grinding wheel 17 with respect to the workpiece W.

(Detailed configuration of grinding wheel platform and peripheral equipment)
Next, the detailed configuration of the grindstone table 15 and its peripheral devices will be described with reference to FIGS. The grinding wheel platform and its peripheral equipment described here correspond to the rotary shaft device of the present invention. As shown in FIG. 2, the grindstone base 15 is formed with a mounting portion 15a so as to protrude downward. A ball screw nut (not shown) is attached to the attachment portion 15a, and a ball screw in the X-axis direction is inserted therethrough.

  Moreover, the X-axis front part of the grindstone base 15 is formed so as to protrude upward. As shown in FIGS. 4 to 6, the X-axis front portion of the grinding wheel platform 15 is formed so as to surround the outer peripheral surface of the rotating shaft 16. Here, the rotating shaft 16 protrudes from both sides of the grinding wheel base 15 in the Z-axis direction, as shown in FIG. As shown in FIGS. 2 and 4 to 6, a drive motor 18 is placed behind the grindstone table 15 in the X-axis direction. The rotary shaft 16 and the output shaft 18a of the drive motor 18 are parallel to each other.

  A plurality of bearings 31 and 32 are disposed at different positions in the axial direction of the rotary shaft 16 between the outer peripheral surface of the rotary shaft 16 and the inner peripheral surface of the through hole of the grindstone table 15. In the present embodiment, the plurality of bearings 31 and 32 are disposed on both ends of the grinding wheel base 15 in the Z-axis direction, and rotatably support the rotary shaft 16 with respect to the grinding wheel base 15.

  In the present embodiment, a known fluid bearing is applied to the plurality of bearings 31 and 32. However, the plurality of bearings 31 and 32 are not limited to fluid bearings, and may be rolling bearings. Moreover, in this embodiment, although the two bearings 31 and 32 are arrange | positioned, you may make it arrange | position three or more bearings. Here, as shown in FIG. 3, the first bearing 31 is arranged on the Z axis direction plus end side (left end side in FIG. 3) from the position of the first bearing 31 arranged on the Z axis direction minus end side (right end side in FIG. 3). A range in the axial direction up to the position of the second bearing 32 is denoted by ΔZ. The axial range ΔZ is the same as the Z-axis direction width of the grindstone table 15, but may be narrower than the Z-axis direction width of the grindstone table 15.

  The first bearing 31 rotatably supports the first supported portion 16a of the rotating shaft 16, and the second bearing 32 supports the second supported portion 16c of the rotating shaft 16 rotatably. A large-diameter intermediate portion 16b is formed between the first supported portion 16a and the second supported portion 16c of the rotating shaft 16. Further, a grinding wheel 17 is attached on the minus side in the Z-axis direction from the first supported portion 16a of the rotating shaft 16. On the other hand, a locking portion 16d on which the belt 19 is laid is formed further on the plus side in the Z-axis direction than the second supported portion 16c of the rotating shaft 16.

  That is, a radial load corresponding to the processing by the grinding wheel 17 mainly acts on the first bearing 31. On the other hand, a radial load corresponding to the tension by the belt 19 mainly acts on the second bearing 32. Therefore, the heat generation amount of the first bearing 31 is highly dependent on the processing load, and the heat generation amount of the second bearing 32 is highly dependent on the load due to tension. Thus, the heat generation amount of the first bearing 31 and the heat generation amount of the second bearing 32 are different.

  Here, the bearing fluid supplied to the plurality of bearings 31 and 32 which are fluid bearings is stored in the tank 51. The bearing fluid stored in the tank 51 is supplied to the plurality of bearings 31 and 32 by the pump 52. A flow path 41 through which the bearing fluid flows from the pump 52 to the plurality of bearings 31 and 32 is formed in the grindstone table 15. Further, in the grindstone table 15, a reservoir portion 42 that temporarily stores the bearing fluid discharged from the bearings 31 and 32 is formed below the first bearing 31 and the second bearing 32 in the axial direction. ing.

  Further, the grinding wheel platform 15 is formed with a discharge flow path 43 for circulating the bearing fluid from the pool portion 42 to the tank 51. The discharge passage 43 is formed so as to extend from the pool portion 42 in the axial direction of the rotary shaft 16. Specifically, the discharge flow path 43 is formed from the pool portion 42 toward the side opposite to the grinding wheel 17, that is, toward the locking portion 16 d of the rotating shaft 16.

  A first type of cooling flow path 61 is formed in the Z-axis direction minus end side (right end side in FIG. 3) from the substantially center of the grinding wheel base 15 toward the circumferential direction outside the axis orthogonal direction of the rotation shaft 16. A plurality of branch flow paths 61a to 61e are formed. Further, the second-type cooling flow path 62 is directed to the Z axis direction plus end side (left end side in FIG. 3) from substantially the center of the grindstone table 15 toward the circumferential direction outward in the axis orthogonal direction of the rotating shaft 16. A plurality of branch flow paths 62a to 62f are formed. That is, the first type cooling channel 61 and the second type cooling channel 62 are formed so as to be adjacent in the axial direction. Here, the plurality of cooling channels 61 and 62 correspond to “a plurality of cooling channels” of the present invention.

  Each branch channel 61a-61e and 62a-62f distribute | circulate a cooling fluid. However, the first type cooling channel 61 and the second type cooling channel 62 are independent of each other, as will be described later. And the some branch flow paths 61a-61e and 62a-62f are formed in the substantially cyclic | annular C-shape as shown in FIG.

  Further, the plurality of branch channels 61a to 61e and 62a to 62f are formed at different positions in the axial direction, respectively, and are formed at equal intervals in the axial direction. That is, the plurality of branch channels 61a to 61e constituting the first type cooling channel 61 are formed at predetermined equal intervals in the axial direction. A plurality of branch flow paths 62a to 62f constituting the second type cooling flow path 62 are formed at predetermined equal intervals in the axial direction. Further, the separation distance between the Z-axis direction positive end side branch flow path 61e constituting the first type cooling flow path 61 and the Z-axis direction negative end side branch flow path 62a constituting the second type cooling flow path 62. Is formed to be equal to the separation distance (a distance corresponding to the predetermined equal interval) of the plurality of branch channels constituting the respective cooling channels 61 and 62.

  As described above, the plurality of branch flow paths 61a to 61e and 62a to 62f correspond to all of the axial range ΔZ from the position of the first bearing 31 to the position of the second bearing 32 (corresponding to “the entire axial range”). ). Specifically, a part of the first type cooling channel 61 (61a to 61c in the present embodiment) is formed on the outer peripheral side of the first bearing 31, and a part of the second type cooling channel 62 (the main book) In the embodiment, 62 d to 62 f) are formed on the outer peripheral side of the second bearing 32, and the rest of each is formed on the outer peripheral side between the first bearing 31 and the second bearing 32.

  Here, among the plurality of branch channels 61a to 61e and 62a to 62f, the branch channels adjacent in the axial direction are separated to form a channel. However, the separation distance between the adjacent branch channels is such a distance that the cooling liquid flowing through each branch channel can sufficiently exhibit the cooling effect between the branch channels. Further, the distance between the branch flow path 61e constituting the first type cooling flow path 61 and the branch flow path 62a constituting the second type cooling flow path 62 is the same as the distance between the other branch flow paths. For this reason, the separation distance between the adjacent branch flow paths 61e and 62a is such a distance that the cooling liquid flowing through the respective branch flow paths 61e and 62a can sufficiently exhibit the cooling effect between the branch flow paths 61e and 62a. Therefore, a cooling effect can be exhibited over the entire bearing-to-bearing range ΔZ in the grindstone table 15 by the coolant flowing through the plurality of branch passages 61a to 61e and 62a to 62f.

  Further, as described above, the heat source in the rotary shaft device includes a plurality of bearings 31 and 32. However, since the plurality of branch passages 61a to 61e and 62a to 62f are formed on the outer peripheral side of the bearings 31 and 32 in the grindstone base 15, the outer peripheral side of the bearings 31 and 32 in the grindstone base 15 is cooled.

  Furthermore, heat is transmitted from the bearings 31 and 32 on both sides between the axial directions of the plurality of bearings 31 and 32 in the grindstone table 15. That is, it is also required to suppress thermal displacement between the plurality of bearings 31 and 32 that are heat generation sources. Therefore, the thermal displacement of the grinding wheel base 15 in all of the inter-bearing range ΔZ can be uniformly reduced, so that all the thermal displacements in the inter-bearing range ΔZ of the grinding wheel base 15 can be reduced. In particular, since some of the plurality of branch passages 61a to 61e and 62a to 62f (61d to 61e and 62a to 62c in the present embodiment) are also formed in the central portion in the axial direction of the grindstone base 15, the heat transfer is performed. Can be surely cut off. Therefore, as a result, the thermal displacement in the part can be reduced. Naturally, heat transfer from the grindstone platform 15 to another member such as the traverse base 14 can be suppressed, and thermal displacement of the other member can be suppressed.

  Further, the plurality of branch passages 61a to 61e and 62a to 62f are formed so as to surround not only the rotary shaft 16 but also the reservoir portion 42 from the outside in the direction perpendicular to the axis. Here, in the present embodiment, the discharge channel 43 is formed so as to extend in the axial direction from the pool portion 42. Therefore, the branch channels 61a to 61e and 62a to 62f are formed so as to further surround the discharge channel 43 from the outside in the direction perpendicular to the axis.

  Here, when a fluid bearing is applied to the first and second bearings 31 and 32, the bearing fluid generates heat. Then, as described above, the bearing fluid flows through the pool portion 42 and the discharge passage 43 in order to be collected. That is, the reservoir portion 42 that stores the bearing fluid is greatly affected by the heat of the generated bearing fluid. Further, the discharge channel 43 is also affected by heat.

  The plurality of branch channels 61 a to 61 e and 62 a to 62 f are formed so as to surround the rotating shaft 16, the reservoir 42, and the discharge channel 43 as described above. Thereby, not only the periphery of the rotating shaft 16 but also the periphery of the pool portion 42 and the periphery of the discharge flow path 43 can be reliably cooled.

  The C-shaped ends of each of the plurality of branch channels 61a to 61e and 62a to 62f are open to the outer peripheral surface of the grindstone base 15, respectively. And the C-shaped one end of several branch flow paths 61a-61e which comprise the 1st type cooling flow path 61 is connected to the 1st inlet branch pipe 71, and a C-shaped other end is a 1st exit branch. It communicates with the tube 72. The C-shaped one ends of the plurality of branch channels 62a to 62f constituting the second type cooling channel 62 communicate with the second inlet branch pipe 73, and the C-shaped other end is the second outlet branch. It communicates with the tube 74.

  The coolant is supplied to the first inlet branch pipe 71 via the first inlet channel 81 by the coolant supply device 80. A first flow rate adjusting valve 82 is provided in the first inlet channel 81 so that a coolant having a preset flow rate flows therethrough. The first outlet branch pipe 72 is communicated with the supply device 80 via the first outlet channel 83.

  Therefore, the flow rate of the coolant supplied from the supply device 80 is adjusted by the first flow rate adjusting valve 82 in the first inlet flow path 81 and supplied to the first inlet branch pipe 71. Subsequently, the coolant supplied to the first inlet branch pipe 71 is discharged to the first outlet branch pipe 72 after flowing through the respective branch channels 61 a to 61 e constituting the first type cooling channel 61. . The coolant discharged to the first outlet branch pipe 72 is returned to the supply device 80 via the first outlet channel 83.

  Further, the coolant is supplied to the second inlet branch pipe 73 via the second inlet channel 84 by the coolant supply device 80. A second flow rate adjusting valve 85 is provided in the second inlet channel 84 so that a coolant having a preset flow rate flows therethrough. The second outlet branch pipe 74 is communicated with the supply device 80 via the second outlet channel 86.

  Therefore, the flow rate of the coolant supplied from the supply device 80 is adjusted by the second flow rate adjusting valve 85 in the second inlet flow path 84 and supplied to the second inlet branch pipe 73. Subsequently, the coolant supplied to the second inlet branch pipe 73 is discharged to the second outlet branch pipe 74 after flowing through the branch channels 62 a to 62 f constituting the second type cooling channel 62. . The coolant discharged to the second outlet branch pipe 74 is returned to the supply device 80 via the second outlet channel 86.

  The flow rate of the coolant flowing through the second flow rate adjustment valve 85 can be the same as or different from the flow rate of the coolant flowing through the first flow rate adjustment valve 82. Usually, both are set differently. That is, the branch channels 61 a to 61 e configuring the first type cooling channel 61 and the branch channels 62 a to 62 f configuring the second type cooling channel 62 are independent.

  Here, independent means that the characteristics of the coolant flowing through the first type cooling flow path 61 and the characteristics of the cooling liquid flowing through the second type cooling flow path 62 can be made different. Means that. In the present embodiment, the flow rate of the coolant varies according to the cooling flow paths 61 and 62 as the characteristics of the coolant. In the present embodiment, the supply device 80 as a cooling source is common, but the supply source may be independent.

  As described above, by changing the flow rate of the coolant flowing through each of the first and second flow rate adjusting valves 82 and 85, the cooling capacity of the first type cooling channel 61 and the second type cooling channel are set. The cooling capacity by 62 can be varied. And the 1st bearing 31 and the 2nd bearing 32 differ in the emitted-heat amount. Therefore, by forming the first type cooling channel 61 and the second type cooling channel 62 independently, it is possible to exhibit a cooling capacity corresponding to the amount of heat generated at each axial position. Therefore, by performing cooling according to the amount of heat generated at the position of the grinding wheel base 15 in the axial direction, it is possible to reduce the difference in thermal displacement in the entire bearing range ΔZ of the grinding wheel base 15.

  As described above, the entire bearing-to-bearing range ΔZ of the grindstone table 15 is uniformly cooled, and the influence of the thermal displacement of the grindstone table 15 can be reduced by adjusting the cooling capacity according to the respective axial positions. And since the thermal displacement of the grindstone base 15 and its surrounding members can be suppressed, the processing accuracy by the grinding machine 1 can be further improved.

<Second embodiment>
Next, the grindstone table 15 and its peripheral devices according to the present embodiment will be described with reference to FIGS. In the above embodiment, the first and second flow rate adjusting valves 82 and 85 are configured to circulate a coolant having a preset flow rate. In the present embodiment, the first and second flow rate adjusting valves 82 and 85 are valves that can control the flow rate. Further, the grinding machine 1 includes a plurality of detectors 91 and 92 and a coolant control device 93.

  The plurality of detectors 91 and 92 apply temperature sensors and are arranged at different positions in the Z-axis direction. The first detector 91 is disposed on the grinding wheel 17 side (Z-axis direction minus side) of the grinding wheel base 15 and on the workpiece W side (X-axis direction minus side) with respect to the rotating shaft 16. On the other hand, the second detector 92 is disposed on the belt 19 side (Z-axis direction plus side) of the grindstone table 15 and on the workpiece W side (X-axis direction minus side) relative to the rotating shaft 16. . Here, the part of the grindstone table 15 closer to the workpiece W than the rotary shaft 16 is a part where thermal displacement greatly affects the machining accuracy.

  The coolant controller 93 controls the first flow rate adjustment valve 82 based on the detection value of the first detector 91, and controls the flow rate of the coolant flowing through the first flow rate adjustment valve 82. The coolant controller 93 controls the flow rate of the coolant flowing through the second flow rate adjustment valve 85 by controlling the second flow rate adjustment valve 85 based on the detection value of the second detector 92. That is, the coolant control device 93 controls the flow rate of the coolant supplied to the first kind of cooling flow path 61 based on the detection value of the first detector 91, and based on the detection value of the second detector 92. The flow rate of the coolant supplied to the second type cooling channel 62 is controlled. For example, the coolant controller 93 controls the flow rate of the circulating coolant to increase as the detected value increases.

  As described above, the range between the bearings of the grindstone table 15 is controlled by controlling the flow rate of the coolant supplied to each of the plurality of cooling passages 61 and 62 in accordance with the detection values by the respective detectors 91 and 92. The difference in thermal displacement in all ΔZ can be reduced.

<Others>
In the first embodiment, by adjusting the first flow rate adjustment valve 82 and the second flow rate adjustment valve 85, the respective cooling flows through the first type cooling channel 61 and the second type cooling channel 62. Liquid flow is adjusted. In addition, a first temperature adjusting device can be provided instead of the first flow rate adjusting valve 82, and a second temperature adjusting device can be provided instead of the second flow rate adjusting valve 85.

  In this case, the coolant having the temperature adjusted by the first temperature adjusting device flows through the first type cooling channel 61, and the coolant having the temperature adjusted by the second temperature adjusting device is used for the second type cooling. It flows through the flow path 62. That is, cooling liquids having different temperatures flow through the branch channels 61 a to 61 e constituting the first type cooling channel 61 and the branch channels 62 a to 62 f constituting the second type cooling channel 62.

  Here, as described in the above embodiment, the first type cooling flow path 61 and the second type cooling flow path 62 are independent, and independent means that the first type cooling flow path 61 is circulated. This means that the characteristic of the coolant to be made and the characteristic of the coolant flowing through the second type cooling channel 62 can be made different. That is, in the case of adjusting the temperature as described above, the “cooling liquid characteristic” corresponds to the temperature of the cooling liquid. Moreover, it is also possible to adjust the temperature while adjusting the flow rate of the coolant flowing through the first type cooling channel 61 and the second type cooling channel 62, respectively.

  In the second embodiment, a first temperature adjusting device may be provided instead of the first flow rate adjusting valve 82, and a second temperature adjusting device may be provided instead of the second flow rate adjusting valve 85. In this case, the coolant control device 93 controls the first and second temperature control devices to control the temperature of each coolant.

  In the above embodiment, each of the branch channels 61a to 61e and 62a to 62f is formed in a C shape. For example, the branch channels 61a to 61e constituting the first type cooling channel 61, and the second The branch channels 62a to 62f constituting the seed cooling channel 62 may be formed in a single spiral shape. In this case, two spiral channels are formed in the grinding wheel platform 15 at different positions in the axial direction.

  In the above embodiment, the same flow rate of the cooling liquid is supplied to the branch flow paths 61 a to 61 e constituting the first type cooling flow path 61, and the branch flow path 62 a constituting the second type cooling flow path 62. The coolant having the same flow rate is supplied to .about.62f. In addition, the flow rate of the coolant supplied to each of the branch channels 61a to 61e and 62a to 62f may be different.

  For example, a flow rate adjusting valve such as a throttle valve may be disposed on the inlet side of each of the branch channels 61a to 61e and 62a to 62f. Moreover, the flow path which supplies a cooling fluid to each branch flow path 61a-61e, 62a-62f from the supply apparatus 80 may each be formed separately, and a flow regulating valve may be arrange | positioned in each flow path. In this case, each of the branch channels 61a to 61e and 62a to 62f corresponds to each cooling channel of the plurality of cooling channels in the present invention. Moreover, you may make it make the temperature of the coolant which distribute | circulates each branch flow path 61a-61e, 62a-62f differ.

  In the second embodiment, the detectors 91 and 92 are temperature sensors that detect the temperature of the grindstone table 15. However, the detectors 91 and 92 detect the temperature of the rotating shaft 16 and the thermal displacement of the grindstone table 15. A displacement sensor and a displacement sensor that detects the thermal displacement of the rotating shaft 16 can also be applied. For example, a displacement sensor that detects thermal displacement detects each displacement relative to a reference such as the bed 11. Further, the thermal displacement of the rotating shaft 16 can detect the radial displacement of the rotating shaft 16 with respect to the grindstone table 15.

  In addition, the present invention is applied to the rotary shaft device including the grindstone table 15, but can also be applied to a rotary shaft device including the main shaft 12 of the grinding machine 1. The present invention can be applied not only to a grinding machine but also to a lathe spindle device, a machining center spindle device, and the like.

1: grinding machine, 15: grinding wheel base (housing), 16: rotating shaft, 17: grinding wheel (rotating tool), 18: driving motor (rotating driving device), 18a: output shaft, 19: belt, 31: first Bearing: 32: second bearing, 42: reservoir, 43: discharge channel, 51: tank, 61: first type cooling channel, 62: second type cooling channel, 61a to 61e: first type 62a to 62f: branch flow paths constituting the second type cooling flow path, 80: supply device, 82: first flow rate adjustment valve, 85: second flow rate adjustment valve, 91, 92: Detector, 93: Coolant control device, W: Workpiece, ΔZ: Range between bearings (axial range)

Claims (6)

A rotation axis;
A housing surrounding an outer peripheral surface of the rotating shaft;
A plurality of bearings disposed between the rotating shaft and the housing, rotatably supporting the rotating shaft with respect to the housing, and disposed at different positions in the axial direction;
With
In the housing, a plurality of cooling passages are formed to flow the cooling liquid independently in the circumferential direction outside the axis orthogonal direction of the rotating shaft at different positions in the axial direction,
The plurality of cooling flow paths are formed over the entire range in the axial direction from the position of the bearing disposed on one axial end side of the plurality of bearings to the position of the bearing disposed on the other axial end side. And
A rotary shaft device that is cooled over the entire axial range of the housing by a coolant flowing through the plurality of cooling channels. The plurality of cooling passages formed in the housing are configured by a plurality of branch passages arranged at equal intervals,
In the cooling flow paths adjacent to each other in the axial direction, a separation distance between a branch flow path on one end side in the axial direction constituting one of the cooling flow paths and a branch flow path on the other end side in the axial direction constituting the other cooling flow path is The rotary shaft device according to claim 1, wherein the rotation shaft device is equal to a separation distance between a plurality of branch channels constituting each of the cooling channels. At least one of the plurality of bearings is a fluid bearing,
The housing is formed with a reservoir for storing the bearing fluid discharged from the fluid bearing,
The rotary shaft device according to claim 1 or 2, wherein the plurality of cooling flow paths are formed so as to surround the rotary shaft and the pool portion from the outside in the axial orthogonal direction. The housing is formed with a discharge flow path for circulating the bearing fluid from the reservoir to the tank,
The rotary shaft device according to claim 3, wherein the plurality of cooling channels are formed so as to surround the rotary shaft, the pool portion, and the discharge channel from the outside in the direction perpendicular to the axis. The rotating shaft device is
A plurality of detectors for detecting at least one of a temperature of the housing, a temperature of the rotating shaft, a thermal displacement of the housing, and a thermal displacement of the rotating shaft at different positions in the axial direction;
A coolant control device for controlling the characteristics of the coolant flowing through each of the plurality of cooling flow paths based on the detection values by the plurality of detectors;
The rotating shaft device according to any one of claims 1 to 4, further comprising: A rotary tool is attached to one axial end of the rotary shaft,
A belt for transmitting the rotational force of the output shaft of the rotary drive device is hung on the other axial end of the rotary shaft,
Of the plurality of bearings, a load arranged on the rotary tool side mainly receives a load corresponding to processing by the rotary tool,
The rotary shaft device according to any one of claims 1 to 5, wherein a load corresponding to a tension by the belt mainly acts on a bearing arranged on the belt side among the plurality of bearings.

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