spindle assembly

Abstract

To provide a main spindle device capable of changing an air flow rate of oil air supplied to a rolling bearing and lubricant amount, with a simple structure.SOLUTION: A main spindle device is equipped with a plurality of rolling bearings, a main spindle, an oil air supplying device that supplies oil air to the plurality of rolling bearings, and a control device. The oil air supplying device has an air supplying device supplying air, an oil supplying device supplying oil, and a mixing valve mixing the air and the oil. The air supplying device has an air source, a first air supplying channel that connects the air source and the mixing valve, a second air supplying channel that branches off from the first air supplying channel at a branch point and merges with the first air supplying channel at a merging point, and a switch valve opening / closing the second air supplying channel.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a spindle device. [Background technology]

[0002] One method for supplying lubricating oil to the bearings of a spindle mounted on a spindle unit is to supply oil using an oil-air system. In this method, the lubricating oil is mixed with air and transported to the bearings by the air flow. It is known that when the spindle rotates at high speed, an air curtain, also known as an air wall, forms around the spindle, making it difficult for the lubricating oil to be supplied to the bearings. Patent Document 1 describes a lubrication method in which the amount of lubricating oil supplied increases as the spindle rotation speed increases. Specifically, the lubrication method described in Patent Document 1 uses a system equipped with an electromagnetic switching valve for switching the amount of lubricating oil supplied, an electromagnetic switching valve for switching the air flow rate, and two mixing nozzles for mixing the lubricating oil and air. The amounts of lubricating oil supplied from the two mixing nozzles are adjusted to be different from each other, and the switching valve is switched depending on the rotation speed to supply lubricating oil from one of the two mixing nozzles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 3-196942 Summary of the Invention [Problem to be solved by the invention]

[0004] In the system described in Patent Document 1, two mixing nozzles are used, which may make the system complicated. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms. According to a first aspect of the present disclosure, there is provided a spindle device comprising: a spindle body, a plurality of rolling bearings arranged on the spindle body, a spindle rotatably supported via the plurality of rolling bearings and having a tool attached to one end thereof, a rotary drive motor for rotating the spindle, an oil-air supply device for supplying oil and air to the plurality of rolling bearings, and a control device for controlling the rotation speed of the rotary drive motor, wherein the oil-air supply device has an air supply device for supplying air, an oil supply device for supplying oil, and a mixing valve for mixing the air and the oil, and the air supply device comprises an air source, a first air supply passage connecting the air source and the mixing valve, a second air supply passage branching from the first air supply passage at a branch point and joining the first air supply passage at a joining point, and a selector valve for opening and closing the second air supply passage. a first fixed throttle disposed in the first air supply flow path between the branch point and the junction point, and a second fixed throttle disposed in the second air supply flow path; With When the switching valve is open, the total flow rate of the air that has flowed through the first fixed throttle and the air that has flowed through the second fixed throttle is supplied to the mixing valve. According to a second aspect of the present disclosure, there is provided a spindle device. the air supply device includes an air source, a first air supply flow path connecting the air source and the mixing valve; a second air supply flow path set to have a flow rate greater than that of the first air supply flow path, the second air supply flow path being branched from the first air supply flow path at a branch point and joining the first air supply flow path at a joining point; a selector valve for selectively selecting either the first air supply flow path or the second air supply flow path as the flow path for supplying air; a first fixed throttle disposed in the first air supply flow path between the branch point and the junction point, and a second fixed throttle disposed in the second air supply flow path; With The flow rate of the air flowing through the second fixed throttle is greater than the flow rate of the air flowing through the first fixed throttle.

[0006] (1) According to one aspect of the present disclosure, there is provided a spindle device. The spindle device includes a spindle body, a plurality of rolling bearings arranged on the spindle body, a spindle rotatably supported via the plurality of rolling bearings and having a tool attached to one end, a rotary drive motor for rotating the spindle, an oil-air supply device for supplying oil and air to the plurality of rolling bearings, and a control device for controlling the rotation speed of the rotary drive motor. The oil-air supply device includes an air supply device for supplying air, an oil supply device for supplying oil, and a mixing valve for mixing the air and the oil. The air supply device includes an air source, a first air supply passage connecting the air source and the mixing valve, a second air supply passage branching from the first air supply passage at a branch point and joining the first air supply passage at a joining point, and a switching valve for opening and closing the second air supply passage. According to this aspect, the air flow rate and the amount of oil in the oil-air mixture supplied to the rolling bearing can be changed with a simple configuration that includes a switching valve for switching the flow rate and a mixing valve. (2) In the spindle unit of the above aspect, the control device may open and close the switching valve using the rotation speed. According to this aspect, the air flow rate of the oil-air mixture supplied to the rolling bearing can be changed by opening and closing the switching valve using the rotation speed. (3) In the spindle unit of the above aspect, the control device may close the switching valve when the rotational speed is equal to or lower than a predetermined reference rotational speed, and open the switching valve when the rotational speed is higher than the reference rotational speed. According to this aspect, when the rotational speed is equal to or lower than the reference rotational speed, the air flow rate of the oil-air supplied to the rolling bearing can be made smaller than the air flow rate when the rotational speed is higher than the reference rotational speed. Therefore, energy savings can be achieved in terms of the power required to supply oil and air. (4) According to one aspect of the present disclosure, there is provided a spindle device comprising: a spindle body, a plurality of rolling bearings arranged on the spindle body, a spindle rotatably supported via the plurality of rolling bearings and having a tool attached to one end thereof, a rotary drive motor for rotating the spindle, an oil / air supply device for supplying oil and air to the plurality of rolling bearings, and a control device for controlling the rotation speed of the rotary drive motor. The oil / air supply device has an air supply device for supplying air, an oil supply device for supplying oil, and a mixing valve for mixing the air and the oil. The air supply device includes an air source, a first air supply flow path connecting the air source and the mixing valve, a second air supply flow path set to have a larger flow rate than the first air supply flow path, the second air supply flow path branching from the first air supply flow path at a branch point and merging with the first air supply flow path at a junction point, and a switching valve that selects either the first air supply flow path or the second air supply flow path as the flow path for supplying the air. According to this aspect, the air flow rate and the amount of oil in the oil-air mixture supplied to the rolling bearing can be changed with a simple configuration that includes a switching valve for switching the flow rate and a mixing valve. (5) In the spindle unit of the above aspect, the control device may use the switching valve to select the first air supply passage when the rotational speed is less than a predetermined reference rotational speed, and may use the switching valve to select the second air supply passage when the rotational speed is equal to or greater than the reference rotational speed. According to this aspect, when the rotational speed is equal to or less than the reference rotational speed, the air flow rate of the oil-air supplied to the rolling bearing can be made smaller than the air flow rate when the rotational speed is greater than the reference rotational speed. Therefore, energy savings can be achieved in terms of the power required to supply oil-air. The present disclosure can be realized in various forms, and in addition to the spindle device described above, can be realized in the form of, for example, a method for controlling a spindle device, a method for manufacturing a spindle device, etc. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. [Figure 2] Enlarged view of region R2 in Figure 1. [Figure 3] FIG. 2 is a schematic diagram showing the configuration of an oil and air supply device. [Figure 4] 10 is a flowchart of a flow rate switching process. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of an oil and air supply device according to a second embodiment. [Figure 6] 10 is a flowchart of a flow rate switching process according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is a schematic diagram showing a longitudinal section of a spindle unit 1 according to an embodiment. The spindle unit 1 according to this embodiment is a motor-built-in type spindle unit provided in a machine tool such as a machining center. The spindle unit 1 holds a tool for machining a workpiece on its front side. Specifically, the tool is configured by attaching a machining tool to a tool holder. FIG. 1 shows a central axis AX of a spindle 10 of the spindle unit 1. The upper half of the drawing above the central axis AX shows an unclamped state in which the tool holder is released from its grip, while the lower half of the drawing below the central axis AX shows a clamped state in which the tool holder is gripped. In addition, with respect to the axial direction along the central axis AX, the side that holds the tool is the front side, and the side opposite the side that holds the tool is the rear side. In addition, the upper side of FIG. 1 corresponds to the vertically upward direction, and the lower side of the drawing corresponds to the vertically downward direction.

[0009] Spindle device 1 includes a cylindrical spindle housing 3 as the main body of the spindle device, spindle 10, a front bearing mechanism 50A, a rear bearing mechanism 50B, an electric motor 40 as a rotation drive motor, a draw bar 30, a collet chuck 20, a disc spring 33, a cylinder device 15, and an NC control device 90 as a control device. Spindle housing 3 has main elements of spindle device 1 such as spindle 10 and electric motor 40 arranged inside.

[0010] The spindle 10 is rotatably supported by the spindle housing 3 via two bearing mechanisms, a front bearing mechanism 50A and a rear bearing mechanism 50B. The spindle 10 has a central axis AX and rotates about the central axis AX by being driven by an electric motor 40. The spindle 10 has one end 10F, which is the front end, and another end 10R opposite the one end 10F. The spindle 10 has a tapered bore 10T penetrating in the axial direction and a spindle cylinder portion 10H. The tapered bore 10T is located at one end, i.e., the one end 10F, and a tool is removably attached to the tapered bore 10T. The spindle cylinder portion 10H is located closer to the other end, i.e., the other end 10R, than the tapered bore 10T. The spindle cylinder portion 10H communicates with the tapered bore 10T.

[0011] The front bearing mechanism 50A is disposed axially in front of the electric motor 40. The rear bearing mechanism 50B is disposed axially in rear of the electric motor 40. The front bearing mechanism 50A and the rear bearing mechanism 50B are interposed between the spindle housing 3 and the spindle 10 in the radial direction of the spindle 10, which is perpendicular to the axial direction. The front bearing mechanism 50A has two bearings 51 as rolling bearings and an outer ring spacer 54. The bearings 51 are angular rolling bearings. The two bearings 51 are disposed with a gap between them in the direction of the central axis AX. The outer ring spacer 54 is disposed between the two bearings 51. As will be described later with reference to FIG. 2 , the outer ring spacer 54 is formed with a nozzle flow path 61 having a main nozzle flow path 61A extending radially inward from the outer peripheral surface of the outer ring spacer 54, a first branch flow path 61B branching from the main nozzle flow path 61A toward the inner ring 55 of the front bearing 51, and a second branch flow path 61C branching from the main nozzle flow path 61A toward the inner ring 55 of the rear bearing 51. Oil-air, which is a mixture of lubricating oil and air, is supplied to the bearing 51 through the main nozzle flow path 61A, the first branch flow path 61B, and the second branch flow path 61C. The rear bearing mechanism 50B has a configuration similar to that of the front bearing mechanism 50A. That is, the rear bearing mechanism 50B has two bearings 51 as rolling bearings, an inner ring spacer 53, and an outer ring spacer 54. The nozzle flow paths 61 and the oil / air supply devices 91 of the front bearing mechanism 50A and the rear bearing mechanism 50B are connected by oil / air supply flow paths 140. That is, there are two oil / air supply flow paths 140 in total, and each may be, for example, an air tube.

[0012] Electric motor 40 includes rotor 41 and stator 42. Electric motor 40 is disposed on the outer periphery of spindle 10 within spindle housing 3. Rotor 41 is configured to be rotatable integrally with spindle 10. Power is supplied to stator 42 under the control of NC control device 90, causing rotor 41 to rotate, which in turn causes spindle 10 to rotate.

[0013] The collet chuck 20 is disposed within the spindle cylindrical portion 10H. The collet chuck 20 moves forward and backward along the axial direction of the spindle 10 in conjunction with the draw bar 30, thereby taking one of two states: a clamped state in which the tool is gripped, and an unclamped state in which the tool is no longer gripped. Specifically, the collet chuck 20 is in the unclamped state when the draw bar 30 is pushed forward by the cylinder device 15 and moves toward the draw bar one end 30F. On the other hand, the collet chuck 20 is in the clamped state when the draw bar 30 is separated from the cylinder device 15 and moves toward the draw bar other end 30R due to the biasing force of the disc spring 33.

[0014] Draw bar 30 is disposed in spindle cylindrical portion 10H. Draw bar 30 has one draw bar end 30F located on the one end 10F side and another draw bar end 30R located on the other end 10R side. Draw bar 30 is movable along the axial direction of spindle 10 by operation of cylinder device 15, which will be described later. Draw bar 30 is connected to spindle 10 so as to move in conjunction with the rotational movement of spindle 10.

[0015] The disc spring 33 is disposed in the spindle cylindrical portion 10H within the spindle 10, between the inner peripheral surface of the spindle 10 and the drawbar 30. The disc spring 33 is disposed axially between a collar 34 disposed on the inner periphery of the spindle 10 and a large-diameter portion 30D formed on the other end 30R of the drawbar 30. Specifically, the disc spring 33 is disposed by being inserted through the outer periphery of the drawbar 30. A plurality of disc springs 33 are provided along the axial direction. The rear end of each disc spring 33 abuts against the large-diameter portion 30D of the drawbar 30 on the other end 30R side of the drawbar 30, facing the axial direction. This causes the disc spring 33 to apply a biasing force in a direction from the one end 10F toward the other end 10R. This biasing force keeps the collet chuck 20 in a clamped state when the cylinder device 15 is not operating.

[0016] The cylinder device 15 is disposed axially rearward of the draw bar 30. The cylinder device 15 has a piston 18 configured to be movable in the axial direction. The piston 18 faces the other end 30R of the draw bar 30 in the axial direction. When the piston 18 moves forward, the draw bar 30 moves forward by the piston 18 against the biasing force of the disc spring 33. This causes the collet chuck 20 to enter an unclamped state.

[0017] The NC control device 90 controls the operation of the spindle device 1 in accordance with an NC (Numerical Control) program stored in memory. For example, the NC control device 90 controls the rotation speed of the electric motor 40 of the spindle device 1.

[0018] The spindle device 1 further includes an oil and air supply device 91. The operation of the oil and air supply device 91 is controlled by the NC control device 90.

[0019] FIG. 2 is an enlarged view of region R2 in FIG. 1. In FIG. 2, "inward" refers to the direction toward center axis AX in the radial direction of main shaft 10, and "outward" refers to the opposite direction of "inward." Front-side bearing mechanism 50A includes an inner ring spacer 53 in addition to the above-described configuration. Inner ring spacer 53 and outer ring spacer 54 are annular seats disposed between two bearings 51. Inner ring spacer 53 and outer ring spacer 54 are disposed with a gap therebetween in the radial direction. As described above, outer ring spacer 54 includes, corresponding to the two bearings 51, a main nozzle flow path 61A extending radially inward from the outer peripheral surface of outer ring spacer 54, a first branch flow path 61B branching from main nozzle flow path 61A toward inner ring 55 of front bearing 51, and a second branch flow path 61C branching from main nozzle flow path 61A toward inner ring 55 of rear bearing 51. The main nozzle flow path 61A, the first branch flow path 61B, and the second branch flow path 61C are drilled holes.

[0020] Bearing 51 has an inner ring 55, an outer ring 56, balls 57 as rolling elements, and a cage 58. Inner ring 55 and outer ring 56 are annular members. Outer ring 56 has a larger diameter than inner ring 55. Multiple balls 57 are arranged between outer ring 56 and inner ring 55. Raceways, on which balls 57 roll, are formed on the surface of outer ring 56 facing inner ring 55 and the surface of inner ring 55 facing outer ring 56. Cage 58 is an annular member arranged between inner ring 55 and outer ring 56. Cage 58 holds multiple balls 57 at intervals. When inner ring 55 rotates in conjunction with the rotation of main shaft 10, balls 57 roll, allowing main shaft 10 to rotate smoothly.

[0021] The oil-air supplied from the oil-air supply device 91 (FIG. 1) flows through the first branch flow path 61B and the second branch flow path 61C and is sprayed onto the two bearings 51. Approximately the same amount of oil-air is supplied to each of the two bearings 51. As a result, the lubricating oil contained in the oil-air is supplied to the balls 57 of the bearings 51, etc.

[0022] FIG. 3 is a schematic diagram showing the configuration of an oil / air supplying device 91 along with the front bearing mechanism 50A and the rear bearing mechanism 50B. The oil / air supplying device 91 includes an air supplying device 96 that supplies air, a lubricating oil supplying device 78 as an oil supplying device, and one mixing valve 81. The lubricating oil supplying device 78 supplies lubricating oil as oil. The mixing valve 81 mixes the air and the lubricating oil. The air supplying device 96 includes an air source 71, a cock 72, a dry filter 73, a first fixed orifice 74, a second fixed orifice 75, an on / off switching valve 76, and an air pressure switch 77. The air source 71 and the mixing valve 81 are connected by a first air supply flow path 85. The second air supply flow path 86 branches from the first air supply flow path 85 at a branch point PO1 and merges with the first air supply flow path 85 at a merging point PO2. A cock 72 and a dry filter 73 are arranged in this order in a first air supply passage 85 between the air source 71 and the branch point PO1. The air source 71 is, for example, an air compressor, and discharges air at a predetermined flow rate. The cock 72 is a valve that opens and closes the first air supply passage 85. The cock 72 is closed when the spindle unit 1 is not performing a machining operation and is open when the spindle unit 1 is performing a machining operation. The dry filter 73 removes foreign matter and moisture contained in the air pressurized from the air source 71. A first fixed throttle 74 is arranged in the first air supply passage 85 between the branch point PO1 and the junction point PO2 to reduce the flow rate of the circulating air. A second fixed throttle 75 and an on / off switching valve 76 are arranged in this order in the second air supply passage 86, from the branch point PO1 toward the junction point PO2. The second fixed throttle 75 reduces the flow rate of the circulating air. The on-off switching valve 76 is a single-acting normally-open solenoid switching valve that is open due to a spring when not energized and closed due to a solenoid when energized. Here, the air flow rate passing through the first fixed orifice 74 and the air flow rate passing through the second fixed orifice 75 are the same, a flow rate A [NL / min]. The flow rate of air discharged from the air source 71 is 2×A [NL / min]. The air pressure switch 77 is disposed in the first air supply flow path 85 between the junction point PO2 and the mixing valve 81.The air pressure switch 77 is used to check whether air is flowing at a target flow rate, and if air is not flowing at the target flow rate, the pressure drops. As described above, the spindle unit 1 has one on-off switching valve 76, which is not arranged in the first air supply flow path 85 but only in the second air supply flow path 86.

[0023] The lubricating oil supply device 78 and the mixing valve 81 are connected by a lubricating oil supply passage 87. The lubricating oil supply device 78 supplies a predetermined amount of lubricating oil to the lubricating oil supply passage 87 at predetermined time intervals. A lubricating oil pressure switch 79 is attached to the lubricating oil supply passage 87. The lubricating oil pressure switch 79 is used to check whether or not the lubricating oil is flowing at a target flow rate, and if the lubricating oil is not flowing at the target flow rate, the pressure drops.

[0024] The mixing valve 81 mixes the air supplied from the first air supply passage 85 with the lubricating oil supplied from the lubricating oil supply passage 87. The mixing valve 81 then divides the oil-air mixture of air and lubricating oil into two portions at approximately the same flow rate and supplies them to each of the two oil-air supply passages 140. As described above, the oil-air is supplied to each of the four bearings 51 through the oil-air supply passage 140.

[0025] When the rotation speed of the spindle 10 is high, a wall of air, also known as an air curtain, forms around the spindle 10, making it difficult for the lubricating oil contained in the air-oil to be supplied to the bearing 51. Therefore, the air flow rate is adjusted to a large value so that the lubricating oil can penetrate the air curtain and be supplied to the balls 57 of the bearing 51. The rotation speed of the spindle 10 in the spindle unit 1 is changed depending on, for example, the type of tool attached. The inventors discovered that when the rotation speed of the spindle 10 is low, a sufficient amount of lubricating oil can be supplied to the bearing 51 even with a smaller air flow rate than when the rotation speed is high. Specifically, based on the results of an experiment in which the air flow rate in the oil-air supply passage 140 was changed and the temperature rise of the bearing 51 was measured, it was confirmed that when the dn value, which indicates the rotation speed of the bearing 51, is 500,000 or less, the air flow rate can be half the air flow rate when the dn value is greater than 500,000. Therefore, in the spindle unit 1 according to this embodiment, the air flow rate supplied to the mixing valve 81 is switched between two levels depending on the rotation speed. As a result, when the rotation speed is low, the air flow rate can be reduced, thereby saving energy in terms of the power required to supply oil-air.

[0026] 4 is a flowchart of a flow rate switching process for switching the air flow rate. The flow rate switching process is part of a processing process in which the NC control device 90 processes a workpiece, and is a process for controlling the rotation of the spindle 10. If the rotation speed instructed to the electric motor 40 is equal to or lower than a predetermined reference rotation speed RSt (step S10: YES), the NC control device 90 closes the on / off switching valve 76 (step S20). Specifically, the NC control device 90 instructs the on / off switching valve 76 to be energized. This closes the on / off switching valve 76, and air is supplied to the mixing valve 81 at a flow rate of A [NL / min]. Then, oil-air is supplied from the mixing valve 81 to each bearing 51 at an air flow rate of A / 4 [NL / min]. After executing step S20, the NC control device 90 ends this processing routine.

[0027] On the other hand, if the rotation speed instructed to the electric motor 40 is not equal to or less than the reference rotation speed RSt, i.e., is greater than the reference rotation speed RSt (step S10: NO), the NC control device 90 opens the on-off switching valve 76 (step S30). Specifically, the NC control device 90 instructs the on-off switching valve 76 to be de-energized. This opens the on-off switching valve 76, and air at 2×A [NL / min] is supplied to the mixing valve 81. Then, oil-air at an air flow rate of A / 2 [NL / min] is supplied from the mixing valve 81 to each bearing 51. After executing step S30, the NC control device 90 ends this processing routine.

[0028] In this embodiment, the rotation speed of the spindle 10 and the state of the on / off switching valve 76, either open or closed, are associated in advance. Therefore, in steps S20 and S30, a word commanding the rotation speed of the spindle 10 may be used to command the on / off switching valve 76 to be de-energized or energized. Alternatively, a word other than the word commanding the rotation speed of the spindle 10 may be used to command the on / off switching valve 76 to be de-energized or energized. Here, a word is the smallest unit of a character string constituting an NC program.

[0029] According to the flow rate switching process, the air flow rate supplied to the bearing 51 when the rotation speed is equal to or lower than the reference rotation speed RSt is set to half the air flow rate supplied to the bearing 51 when the rotation speed is higher than the reference rotation speed RSt. This makes it possible to reduce the air flow rate, thereby contributing to energy savings in the power consumption of the spindle unit 1. Furthermore, the air flow rate of the oil-air mixture and the amount of lubricating oil supplied to the bearing 51 can be changed using one mixing valve 81 and one on-off switching valve 76.

[0030] In this embodiment, the diameter of the spindle 10 is 120 mm, and the reference rotation speed RSt is 4000 min -1 ] and the flow rate A [NL / min] is 80 [NL / min].

[0031] According to the embodiment described above, the spindle unit 1 includes a plurality of bearings 51, an electric motor 40, an oil / air supplying device 91 that supplies oil / air to the plurality of bearings 51, and an NC control device 90. The oil / air supplying device 91 has an air supplying device 96, a lubricating oil supplying device 78, and a mixing valve 81. The air supplying device 96 has an air source 71, a first air supply flow path 85, a second air supply flow path 86, and an on / off switching valve 76 that opens and closes the second air supply flow path 86. Therefore, with a simple configuration that includes one on / off switching valve 76 and one mixing valve 81, it is possible to change the air flow rate of the oil / air and the amount of lubricating oil supplied to the bearings 51.

[0032] In the flow rate switching process, the NC control device 90 opens and closes the on-off switching valve 76 using the rotation speed of the spindle 10. This makes it possible to change the air flow rate of the oil-air supplied to the bearing 51 using the rotation speed of the spindle 10.

[0033] In the flow rate switching process, if the rotation speed of the spindle 10 is equal to or higher than the reference rotation speed RSt (step S10: YES), the NC control device 90 closes the on-off switching valve 76 (step S20). On the other hand, if the rotation speed of the spindle 10 is higher than the reference rotation speed RSt (step S10: NO), the NC control device 90 opens the on-off switching valve 76 (step S30). Therefore, when the rotation speed of the spindle 10 is equal to or lower than the reference rotation speed RSt, the air flow rate of the oil-air supplied to the bearing 51 can be made smaller than the air flow rate when the rotation speed is higher than the reference rotation speed RSt. This makes it possible to save energy in terms of the power required to supply oil-air.

[0034] B. Second embodiment: 5 is a schematic diagram showing the configuration of an oil and air supply device 191 according to this embodiment. An air supply device 196 included in the oil and air supply device 191 according to this embodiment differs from the air supply device 96 according to the first embodiment in that it does not have an on-off switching valve 76 but has a flow path switching valve 176, and in that the air flow rate of the second air supply flow path 86 is different. The same components as those in the first embodiment are given the same reference numerals, and detailed explanations will be omitted as appropriate.

[0035] The air source 71 and the mixing valve 81 are connected by a first air supply flow path 185. The second air supply flow path 186 branches off from the first air supply flow path 185 at a branch point PO1 and merges with the first air supply flow path 185 at a junction point PO2. A cock 72 and a dry filter 73 are arranged in this order in the first air supply flow path 185 between the air source 71 and the branch point PO1. A flow path switching valve 176 is arranged at the branch point PO1 as a selector valve. The flow path switching valve 176 alternatively selects either the first air supply flow path 185 or the second air supply flow path 186 as the flow path for supplying air. Specifically, the flow path switching valve 176 selects the first air supply flow path 185 as the flow path that is opened by a solenoid when energized, and selects the second air supply flow path 186 as the flow path that is opened by a spring when de-energized. A first fixed throttle 74 for reducing the flow rate of air passing through is disposed in the first air supply flow path 185 between the branch point PO1 and the junction point PO2. A second fixed throttle 175 for reducing the flow rate of air passing through is disposed in the second air supply flow path 186. The second air supply flow path 186 is set to have a larger flow rate than the first air supply flow path 185. Specifically, the flow resistance of the second fixed throttle 175 is half that of the first fixed throttle, and the flow rate passing through the second fixed throttle 175 is set to 2×A [NL / min], which is twice the flow rate A [NL / min] of the first air supply flow path 185 from the branch point PO1 to the junction point PO2.

[0036] FIG. 6 is a flowchart of the flow rate switching process according to this embodiment. The same process steps as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. When the rotation speed instructed to the electric motor 40 is equal to or lower than a predetermined reference rotation speed RSt (step S10: YES), the NC control device 90 selects the first air supply flow path 185 using the flow path switching valve 176 (step S50). Specifically, the NC control device 90 instructs the flow path switching valve 176 to connect the first air supply flow path 185 and disconnect the second air supply flow path 186. This causes air to be supplied to the mixing valve 81 at a flow rate of A [NL / min]. Then, oil-air with an air flow rate of A / 4 [NL / min] is supplied from the mixing valve 81 to each bearing 51. After executing step S50, the NC control device 90 terminates this process routine.

[0037] On the other hand, if the rotation speed instructed to the electric motor 40 is not equal to or less than the reference rotation speed RSt, i.e., is greater than the reference rotation speed RSt (step S10: NO), the NC control device 90 uses the flow path switching valve 176 to select the second air supply flow path 186 (step S60). Specifically, the flow path switching valve 176 is instructed to close the first air supply flow path 185 and open the second air supply flow path 186. As a result, air is supplied to the mixing valve 81 at an air flow rate of 2×A [NL / min]. Then, oil air is supplied from the mixing valve 81 to each bearing 51 at an air flow rate of A / 2 [NL / min]. After executing step S60, the NC control device 90 ends this processing routine.

[0038] According to the embodiment described above, the air supply device 96 has the air source 71, the first air supply flow path 85, the second air supply flow path 86 set to have a larger flow rate than the first air supply flow path 85, and the flow path switching valve 176 that alternatively selects either the first air supply flow path 185 or the second air supply flow path 186 as the flow path to supply air. Therefore, with a simple configuration that includes one flow path switching valve 176 and one mixing valve 81, it is possible to change the air flow rate of the oil-air and the amount of lubricating oil supplied to the bearing 51.

[0039] In the flow rate switching process, if the rotation speed of the spindle 10 is equal to or higher than the reference rotation speed RSt (step S10: YES), the NC control device 90 uses the flow path switching valve 176 to select the first air supply flow path 185 as the flow path for supplying air (step S50). On the other hand, if the rotation speed of the spindle 10 is higher than the reference rotation speed RSt (step S10: NO), the NC control device 90 uses the flow path switching valve 176 to select the second air supply flow path 186 as the flow path for supplying air (step S60). Therefore, when the rotation speed of the spindle 10 is equal to or lower than the reference rotation speed RSt, the air flow rate of the oil-air supplied to the bearing 51 can be made smaller than the air flow rate when the rotation speed is higher than the reference rotation speed RSt. This makes it possible to save energy in terms of the power required for supplying oil-air.

[0040] C. Other Embodiments: (C1) In the above embodiment, the oil-air contains the lubricating oil in liquid form. Alternatively, the oil-air may contain the lubricating oil in mist form. Also, in the above embodiment, the spindle device 1 is a device that performs processing using a tool. The spindle device is not limited to this and may be, for example, a skiving machine or a grinding machine.

[0041] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0042] 1...spindle device, 3...spindle housing, 10...spindle, 10F...one end, 10H...spindle cylindrical portion, 10R...other end, 10T...tapered hole, 15...cylinder device, 18...piston, 19...opening, 20...collet chuck, 30...draw bar, 30D...large diameter portion, 30F...draw bar one end, 30R...draw bar other end, 33...disc spring, 34...collar, 40...electric motor, 41...rotor, 42...stator, 50A...front side bearing mechanism, 50B...rear side bearing mechanism, 51...bearing, 53...inner ring spacer, 54...outer ring spacer, 55...inner ring, 56...outer ring, 57...ball, 58...retainer, 61...nozzle flow passage, 61A...main nozzle flow passage, 61B... First branch flow path, 61C...second branch flow path, 71...air source, 72...cock, 73...dry filter, 74...first fixed orifice, 75,175...second fixed orifice, 76...on / off switching valve, 77...air pressure switch, 78...lubricating oil supply device, 79...lubricating oil pressure switch, 81...mixing valve, 85,185...first air supply flow path, 86,186...second air supply flow path, 87...lubricating oil supply flow path, 90...NC control device, 91,191...oil / air supply device, 96,196...air supply device, 140...oil / air supply flow path, 176...flow path switching valve, AX...center axis, PO1...branch point, PO2...junction point, R2...area, RSt...reference rotation speed

Claims

1. A spindle device, a spindle device body; A plurality of rolling bearings arranged in the spindle body; a main shaft rotatably supported via the plurality of rolling bearings and having a tool attached to one end thereof; a rotary drive motor that rotates the main shaft; an oil / air supply device that supplies oil / air to the plurality of rolling bearings; a control device that controls the rotation speed of the rotary drive motor, The oil and air supply device is an air supply device that supplies air; an oil supply device that supplies oil; a mixing valve for mixing the air and the oil; The air supply device is An air source; a first air supply passage connecting the air source and the mixing valve; a second air supply flow path that branches off from the first air supply flow path at a branch point and merges with the first air supply flow path at a junction point; a switching valve that opens and closes the second air supply flow path; a first fixed throttle disposed in the first air supply flow path between the branch point and the junction point; a second fixed throttle disposed in the second air supply flow path, a spindle device in which, when the switching valve is open, a total flow rate of the air that has flowed through the first fixed orifice and the air that has flowed through the second fixed orifice is supplied to the mixing valve.

2. The spindle device according to claim 1, The control device A spindle device that opens and closes the switching valve using the rotation speed.

3. The spindle device according to claim 2, The control device When the rotation speed is equal to or lower than a predetermined reference rotation speed, the switching valve is closed; When the rotation speed is greater than the reference rotation speed, the switching valve is opened.

4. A spindle device, a spindle device body; a plurality of rolling bearings disposed in the spindle body; a main shaft rotatably supported via the plurality of rolling bearings and having a tool attached to one end thereof; a rotary drive motor that rotates the main shaft; an oil / air supply device that supplies oil / air to the plurality of rolling bearings; a control device that controls the rotation speed of the rotary drive motor, The oil and air supply device is an air supply device that supplies air; an oil supply device that supplies oil; a mixing valve for mixing the air and the oil; The air supply device is An air source; a first air supply passage connecting the air source and the mixing valve; a second air supply flow path set to have a flow rate greater than that of the first air supply flow path, the second air supply flow path branching off from the first air supply flow path at a branching point and merging with the first air supply flow path at a merging point; a selector valve that selectively selects either the first air supply flow path or the second air supply flow path as a flow path for supplying the air; a first fixed throttle disposed in the first air supply flow path between the branch point and the junction point; a second fixed throttle disposed in the second air supply flow path, a flow rate of the air flowing through the second fixed orifice is greater than a flow rate of the air flowing through the first fixed orifice.

5. The spindle device according to claim 4, The control device When the rotation speed is equal to or lower than a predetermined reference rotation speed, the first air supply passage is selected using the switching valve; When the rotation speed is greater than the reference rotation speed, the second air supply passage is selected using the switching valve.

Images