JP2021042773A - Slide thrust bearing device and rotary workpiece head using slide thrust bearing device - Google Patents

Abstract

To provide a slide thrust bearing device having high vibration control property, quietness property and load bearing property.SOLUTION: A slide thrust bearing device 100 comprises a rotational shaft 102 having a plane perpendicular to an axial line, a base member 110 having a bearing surface 112 facing a contact surface 108 of the rotational shaft, and a slide member 10 that is attached to the bearing surface and constitutes a slide surface together with the contact surface of the rotational shaft. The slide member is formed in an annular shape; has a plurality of convex parts 16 formed and coming into contact with the plain of the bearing member; has a lubricant pocket 14 that communicates so that lubricant flows around each convex part; opens to the inner and outer peripheral parts of the lubricant pocket; and has a lubricant return passage 118 formed that returns the lubricant accumulated on the outer side in a radial direction to the inner side in the radial direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sliding thrust bearing device that rotatably supports a rotating spindle such as a rotary work head on a spindle housing. The present invention also relates to a rotary work head using the sliding thrust bearing device.

The rotary spindle is rotatably supported by a spindle housing or the like by a radial ball bearing or a radial roller bearing. Since such radial bearings cannot support the rotating spindle with respect to axial loads, they may be combined with rolling thrust bearings or cross roller bearings may be used in place of ball bearings.

Patent Document 1 describes a linear (linear motion) guide, but a guide device for a moving body in which a sliding member is attached to a moving body to support and guide the sliding member while contacting the guide surface of the support. Is described. The guide device is provided with a lubricating oil return passage that opens on the sliding surface and a lubricating oil supply passage and a lubricating oil discharge passage that communicate with each other in the lubricating oil return passage, and slides as the moving body moves. While returning the lubricating oil between the surface and the lubricating oil return passage, the lubricating oil is supplied from the lubricating oil source to the sliding surface through the lubricating oil supply passage, and from the sliding surface to the outside through the lubricating oil discharge passage. Lubricating oil is discharged to.

Japanese Unexamined Patent Publication No. 2013-09142

Rolling thrust bearings and cross-roller bearings have low friction and exhibit high load bearing capacity (high rigidity) against thrust load, but they have low damping properties and cannot reduce vibration, and the roundness accuracy of rotation is not high. There's a problem.

Further, the conventional static pressure sliding thrust bearing has a problem that the load capacity is small and indentation is easily formed when it comes into direct contact with the bearing. Further, in the static pressure sliding thrust bearing, there is a problem that the lubricating oil leaks when the supply pressure of the lubricating oil is increased in order to increase the load bearing capacity.

An object of the present invention is to solve the problems of the prior art, and while taking advantage of the high rigidity and low friction of the rolling thrust bearing, slipping with further improved vibration damping, quietness, rotational accuracy, and load bearing capacity. It is an object of the present invention to provide a thrust bearing device.

In order to achieve the above object, according to the present invention, in a sliding thrust bearing device that supports a rotating shaft body in the axial direction with respect to a bearing member, a rotating shaft body having at least one plane perpendicular to the axis line and a rotating shaft body. A sliding member having a flat surface facing the flat surface of the rotating shaft body and a sliding member attached to the flat surface of the bearing member and forming a sliding surface between the flat surface of the rotating shaft body. , A plurality of convex portions abutting with the flat surface of the bearing member are formed on the sliding surface, and a concave portion is formed so as to allow lubricating oil to flow around each convex portion. A sliding member formed in an annular shape concentric with the axis, and a lubricating oil formed in the bearing member and opened at the radial inner and outer positions of the lubricating oil pocket, and the lubricating oil accumulated on the radial outer side is collected in the radial direction. A sliding thrust bearing device is provided that includes at least one lubricating oil return passage that returns inward.

Further, according to the present invention, in a rotary work head that is placed on a table of a machine tool and rotatably attaches a workpiece to be machined, a spindle housing fixed to the table and a sliding thrust bearing device according to claim 1 are provided. The rotary spindle body of the above, comprising a rotary spindle rotatably supported by the spindle housing, and a spindle motor disposed in the spindle housing and rotationally driving the rotary spindle, according to claim 1. A rotary work head is provided in which the rotating spindle is also supported in the axial direction by the spindle housing having the bearing member, the sliding member, and the lubricating oil return passage of the sliding thrust bearing device.

According to the present invention, a sliding member is attached to a flat surface of the bearing member facing the flat surface of the rotating shaft body, and this is used as a sliding surface when the rotating shaft body rotates with respect to the bearing member. While taking advantage of the low frictional properties of thrust bearings, it is possible to further improve vibration damping, quietness, rotational accuracy, and load bearing capacity.

It is an exploded perspective view of the sliding thrust bearing apparatus according to a preferable embodiment of this invention. It is a partial cross-sectional view of the sliding thrust bearing device of FIG. 1 shown together with the lubricating oil supply device. It is a top view of the sliding member. It is an enlarged view of the convex part of the sliding member of FIG. It is sectional drawing of the rotary work head using the sliding thrust bearing apparatus of this invention. It is a perspective view which shows an example of a sliding radial bearing.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
In FIGS. 1 to 4, the sliding thrust bearing device 100 according to a preferred embodiment of the present invention includes a rotating shaft 102 as a rotating shaft body, a base member 110 as a bearing member, and a bottom friction resin attached to the base member 110. It is provided with a sliding member 10 made of.

The base member 110 is a hollow cylindrical member, and one end surface of an annular shape perpendicular to the central axis O is an annular bearing surface 112 that supports the rotating shaft 102 in the axial direction. The base member 110 is formed with first and second passages 114 and 116 extending between the bearing surface 112 and the cylindrical outer surface. The first passage 114 has a radial passage 114a extending in the radial direction from the outer surface and an axial passage 114b extending axially from the radial passage 114a toward the bearing surface 112. The second passage 116 has a radial passage 116a extending radially from the side surface and an axial passage 116b extending axially from the radial passage 116a toward the bearing surface 112.

In the axial passages 114b and 116b of the first and second passages 114 and 116, preferably, the axial passage 114b of the first passage 114 is radially inside the axial passage 116b of the second passage 116. It opens to the support surface 112 and is arranged so that the openings are aligned in the radial direction. The base member 110 preferably has the first and second passages 114 and 116 arranged in this way as one set, and a plurality of sets arranged at equal angular intervals in the circumferential direction, and in the present embodiment, four sets. The first and second passages 114 and 116 of the above are provided.

A lubricating oil return passage 118 is formed between the axial passages 114b and 116b of the first and second passages 114 and 116. The lubricating oil return passage 118 is, for example, a cutting tool such as a drill (FIG.) so as to penetrate the axial passages 114b and 116b of the first and second passages 114 and 116 from the cylindrical outer surface of the base member 110. It can be formed by drilling a hole in the radial direction with (not shown) and then closing the opening with a plug 118a.

The rotating shaft 102 has a cylindrical main body portion 104 and an extension portion 106 protruding from one end surface of the main body portion 104 along the central axis O. The rotary shaft 102 can be, for example, a rotary spindle of a work head attached to a table of a machine tool. The extension portion 106 is formed in a cylindrical or cylindrical shape and is inserted into the hollow portion of the base member 110. The extension portion 106 forms an annular contact surface 108 facing the support surface 112 of the base member 110 on the one end surface of the main body portion 104. The contact surface 108 is a plane perpendicular to the central axis O.

A sliding member 10 made of an annular thin plate-shaped low-friction resin is attached to the bearing surface 112 of the base member 110. The sliding member 10 can be made of a low-friction resin material having high wear resistance and a low coefficient of friction, for example, a bearing material which is formed in a thin plate shape from a fluororesin and is commercially available under the trade names of Turkite and Bearry. The sliding member 10 scrapes the surface of the bearing member on one side surface of the thin plate-shaped bearing material cut to a predetermined size by a machining center using a rotary tool such as an end mill, leaving a land portion and a convex portion. This can be manufactured by forming a lubricating oil pocket. The cutting process of the sliding member 10 is performed by fixing the sliding member 10 to the table of the machining center using a vacuum chuck.

Referring to FIG. 3, the sliding member 10 is located between the land portions 12a and 12b extending along the outer and inner circumferences thereof and the land portions 12a and 12b on the surface of the rotating shaft 102 facing the contact surface 108. A defined lubricating oil pocket 14, a large number of convex portions 16 arranged in the lubricating oil pocket 14, and first and second ports 18a and 18b opening in the lubricating oil pocket 14 are formed. The number and dimensions of the convex portions 16 are determined so that the total area of the surface of the convex portions 16 in the lubricating oil pocket 14 is preferably 15 to 50% of the area inside the land portions 12a and 12b. ..

Referring to FIG. 4, the convex portion 16 has an elongated shape having a _{major axis A j} and a minor _{axis A n.} Both ends of the convex portion 16 _{along the major axis A j} are formed wider than the central portion. Preferably, the convex portion 16, both side portions across the minor axis A _n is recessed in an arc shape having a radius R _1. Further, the convex portion 16 bulges in an arc shape having both ends in the _{major axis A j direction having a radius R 2.}

Further, the convex portion 16 is _{inclined so that the major axis A j is inclined with respect to the tangential direction DT} around the central axis O at predetermined angles α and −α (only the angle α is shown in FIG. 4). Is formed in. More specifically, the convex portion 16 is regularly machined so that the inclination angles α and −α of the major axis A _{j with respect to the tangential direction DT alternate with each other.} The inclination angle α of the major axis A _j with respect to the tangential direction D _T can be appropriately selected depending on the moving speed of the rotating shaft 102, the viscosity of the lubricating oil used, and the like.

In the examples of FIGS. 3 and 4, the inclination angle α = 45 ° of the convex portion 16 is set, but depending on the rotation speed of the rotating shaft 102, the viscosity of the lubricating oil, etc., α = 60 ° or 30 °. The inclination angle of the convex portion 16 with respect to the tangential direction _{DT can be changed.} For example, when the rotation shaft 102 rotates at a higher speed, the _{inclination angle α with respect to the tangential direction DT} is made gentle so that α = 30 °, and the centrifugal force generated by the flow of the lubricating oil causes the rotation axis 102 to move outward in the radial direction. The flow rate of the lubricating oil to be transported can be reduced.

In this way, _{by arranging the convex portions 16 so that the inclination angles α and −α alternate with respect to the tangential direction DT} of the rotating shaft 102, the inside of the lubricating oil pocket 14 is contained while the rotating shaft 102 rotates. Due to its viscosity, the lubricating oil is dragged by the surface of the rotating shaft 102 _{and flows in the same direction as the tangential direction DT} of the rotating shaft 102, and when it hits the convex portion 16, it faces the centrifugal force. It also flows in the direction toward the central axis O of the rotating shaft 102.

The first port 18a and the second port 18b are arranged on the inner peripheral portion and the outer peripheral portion of the sliding member 10 so as to be separated from each other in the radial direction of the base member 110 (support surface 112), and the sliding member 10 It is formed so as to open into the lubricating oil pocket 14 in the thickness direction from the back surface of the. Further, the land portions 12a and 12b are formed at substantially the same height as the convex portion 16 in the lubricating oil pocket 14, and the surfaces of the land portions 12a and 12b and the convex portion 16 are the outer periphery of the contact surface 108 of the rotating shaft 102. While in direct contact with the surface, it slides relative to the rotating shaft 102.

In the illustrated embodiment, one annular sliding member 10 is attached to the bearing surface 112 of the base member 110, but a plurality of sliding members (not shown) can be attached. In this case, the sliding member can have a sector shape consisting of two arcs having a common center and different radii and two lines extending in the radial direction between the two arcs in a plan view. ..

With reference to FIG. 2, the sliding thrust bearing device 100 can be connected to the lubricating oil supply device 320. The lubricating oil is supplied from the lubricating oil supply device 320 to the first passage 114 via the lubricating oil supply pipeline 322, and is collected from the second passage 116 to the lubricating oil supply device 320 via the lubricating oil discharge pipeline 324. Will be done.

The lubricating oil supply device 320 cools the lubricating oil to keep the temperature constant by cooling the lubricating oil tank 326 for storing the lubricating oil recovered from the sliding thrust bearing device 100 via the second passage 116 and the lubricating oil discharge pipeline 324. To the discharge side of the pump 330 and the pump 330 that suck the lubricating oil from the lubricating oil temperature control device 328 for control and the lubricating oil tank 326 and pump the lubricating oil to the first passage 114 via the lubricating oil supply pipeline 322. It is provided with an accumulator 332 that removes the pulsation generated in the lubricating oil by the pump 330.

The accumulator 332 may be omitted if a pump with less pulsation is used or if the influence of pulsation is not a problem. The lubricating oil temperature control device 328 and the pump 330 are controlled by the lubricating oil control device 340. The lubricating oil control device 340 can be configured as, for example, a part of a machine to which the sliding thrust bearing device 100 is applied, for example, a machine control device (not shown) of a machine tool, or a part of an NC device.

Further, the lubricating oil tank 326 divides the internal space into a receiving side tank 326a and a supply side tank 326b by a partition wall 326c, and stores new lubricating oil and lubricating oil from the lubricating oil discharge pipeline 324 in the receiving side tank 326a. Then, the lubricating oil stored in the receiving side tank 326a is temperature-adjusted by the lubricating oil temperature control device 328 and stored in the supply side tank 326b, and the lubricating oil is slipped from the supply side tank 326b by the pump 330 and is a thrust bearing device. It can be supplied to 100.

When the rotating shaft 102 rotates, the lubricating oil in the lubricating oil pocket 14 is dragged by the abutting surface 108 of the rotating shaft 102 due to its viscosity, and flows in the circumferential direction with respect to the sliding member 10. At this time, a centrifugal force acts on the lubricating oil, and the lubricating oil flows outward in the radial direction while flowing in the circumferential direction, and in the lubricating oil pocket 14, the outer peripheral portion provided with the second port 18b is relative. The pressure becomes high, and the inner peripheral portion where the first port 18a is provided becomes low pressure.

In this way, the lubricating oil in the lubricating oil pocket 14 flows to the outer periphery by centrifugal force while flowing in the circumferential direction, and is discharged from the second port 18b to the axial passage 116b of the second passage 116. A part of the lubricating oil in the axial passage 116b of the second passage 116 flows into the lubricating oil return passage 118, and the rest flows into the axial passage 116b and the radial passage 116a of the second passage 116. It is circulated and then recovered to the lubricating oil supply device 320 via the lubricating oil discharge line 324.

The low-temperature lubricating oil supplied from the lubricating oil supply device 320 to the first passage 114 via the lubricating oil supply pipeline 322 merges with the heated lubricating oil from the lubricating oil return passage 304 in the axial passage 114b. Then, it flows into the lubricating oil pocket 14 from the first port 18a. The lubricating oil that has flowed into the lubricating oil pocket 14 flows in the circumferential direction and flows through the lubricating oil pocket 14 toward the second port 18b side. In this way, the sliding member 10 and the rotating shaft 102 are cooled by the replacement action of the lubricating oil.

According to the present embodiment, the lubricating oil between the sliding member 10 and the outer surface of the rotating shaft 102 can be directly cooled, and the heat generating region of the contact surface 108 of the sliding member 10 and the rotating shaft 102 is directly cooled. It will be possible. Further, since the lubricating oil is supplied to the lubricating oil pocket 14 surrounded by the land portions 12a and 12b formed on the sliding member 10, leakage occurs between the sliding member 10 and the contact surface 108 of the rotating shaft 102. The amount of lubricating oil to be used is reduced. Further, by adjusting the pressure of the lubricating oil supplied to the lubricating oil pocket 14, the load capacity in the axial direction of the sliding thrust bearing device 100 can be increased or decreased.

Further, as described above, the lubricating oil in the lubricating oil pocket 14 collects on the outer peripheral portion due to centrifugal force, and the pressure on the outer peripheral portion becomes higher than that on the inner peripheral portion. The lubricating oil collected on the outer peripheral portion of the lubricating oil pocket 14 can be discharged from the second port 18b, but the amount of lubricating oil corresponding to the discharged lubricating oil amount can be discharged from the first port 18a into the lubricating oil pocket 14. Must be supplied to. Although it is possible to supply new lubricating oil into the lubricating oil pocket 14 even if the lubricating oil return passage 304 is not provided, as in the present embodiment, the lubricating oil return passage 304 is provided to provide one of the lubricating oils. By circulating the portions, it is possible to reduce the bias of the pressure of the lubricating oil in the lubricating oil pocket 14 while reducing the amount of lubrication supplied from the lubricating oil supply device 320.

Next, a rotary work head using the sliding thrust bearing device of the present invention will be described with reference to FIGS. 5 and 6.
Referring to FIG. 5, the rotary work head 600 is a device that rotatably attaches a work W to be placed, fixed, and machined on a table 624 of a machine tool. The rotary workhead 600 has a hollow cylindrical spindle housing 612 fixed to the table 624 and a rotary spindle 606 rotatably supported by the spindle housing 612. In the spindle housing 612, the opening on the rear end side is closed by the rear end plate 602, and the opening on the front end side is closed by the front end plate 604.

The rotary spindle 606 is rotatably supported by the spindle housing 612 by a rear radial bearing 620, a principal radial bearing 630 and a sliding thrust bearing 640. The rear radial bearing 620 can be formed, for example, by a sliding radial bearing similar to the sliding thrust bearing described above. The sliding radial bearing has a bearing ring 622 that fits into the central opening 602a of the rear end plate 602, and a sliding member 20 (FIG. 6) is attached to the inner peripheral surface of the bearing ring 622.

The sliding member 20 is formed of a thin plate-shaped cylindrical member made of a low friction resin material having high wear resistance and a low friction coefficient, for example, a fluororesin, and is formed on the inner peripheral surface of the cylindrical member in the same manner as the sliding member 10. The land portion 22, the lubricating oil pocket 24, and the convex portion 26 of the above are formed. However, since centrifugal force does not act on the lubricating oil flowing in the lubricating oil pocket 24 as in the case of the sliding member 10, the first and second ports 28a and 28b are on opposite sides in the radial direction of the cylindrical member. Is formed in.

The bearing ring 622 is formed with first and second ports 624a and 624b communicating with the first and second ports 18a and 18b of the sliding member 10 in the radial direction, and the rear end plate 602 has a first port. The first and second passages 626a and 626 communicating with the second ports 624a and 624b are formed in the radial direction.

The main radial bearing 630 is formed in the same manner as the rear radial bearing 620, has a sliding member 20 attached to the inner peripheral surface of the spindle housing 612, and the spindle housing 612 has a sliding member 20 of the sliding member 20. The first and second passages 636a and 636b communicating with the first and second ports 28a and 28b are formed in the radial direction.

The sliding thrust bearing 640 is formed by the sliding thrust bearing device 100 described above, and supports the rotating spindle 606 on the spindle housing 612 in the axis _{OR W direction.} The rotary spindle 606 has a flange portion 606a that forms a support surface 112 of the rotary shaft 102 of the sliding thrust bearing 10 of FIGS. 1 to 4.

A spacer 642 and a flange portion 606a are sandwiched between the front end plate 604 and the spindle housing 612. The sliding member 10 is attached to the end surface of the spindle housing 612 facing the flange portion 606a and the end surface of the front end plate 604 facing the flange portion 606a. In this example, the flange portion 606a provides the contact surface 108 of the rotating shaft 102 of FIGS. 1 and 2, and the end faces of the spindle housing 612 and the front end plate 604 facing the flange portion 606a are the bearings of FIGS. 1 and 2. The surface 112 is provided. The surface pressure applied to the sliding member 10 can be adjusted by the thickness of the spacer 642.

A face plate 618 is fixed to the tip of the rotary spindle 606, and the work W is attached to the face plate 618. A rotor 608 is fixed to the outer peripheral surface on the rear end side of the rotary spindle 606. A stator 610 is fixed to the inner peripheral surface of the spindle housing 612 so as to face the rotor 608. The rotor 608 and the stator 610 form a built-in motor for the rotary workhead 600.

10 Sliding member 12a Land part 12b Land part 14 Lubricating oil pocket 16 Convex part 18a First port 18b Second port 100 Sliding thrust bearing device 102 Rotating shaft 114 First passage 116 Second passage 118 Lubricating oil return passage 320 Lubricating oil supply device

Claims (4)

In a sliding thrust bearing device that supports a rotating shaft body in the axial direction with respect to a bearing member,
A rotating shaft having at least one plane perpendicular to the axis,
A bearing member having a plane facing the plane of the rotating shaft body and
A plurality of sliding members that are attached to the flat surface of the bearing member and form a sliding surface with the flat surface of the rotating shaft body, and that the sliding surface is in contact with the flat surface of the bearing member. Lubricating oil pockets in which the convex portions of the above are formed and the concave portions are formed so as to allow the lubricating oil to flow around each convex portion, and the sliding member formed in an annular shape concentric with the axis.
At least one lubricating oil return passage formed in the bearing member, opened at the radial inner position and the outer position of the lubricating oil pocket, and returns the lubricating oil accumulated on the radial outer side to the inner side in the radial direction.
A sliding thrust bearing device characterized by being equipped with. The sliding member is made of a thin plate-shaped annular member made of a low-friction resin, and is formed in a lubricating oil pocket formed of a recess in which an inner peripheral portion and an outer peripheral portion are surrounded by a land portion, and in the lubricating oil pocket. It has a plurality of convex portions, and in the lubricating oil pocket of the sliding member, a first port arranged on the inner peripheral portion separated from each other in the radial direction and a first port arranged on the outer peripheral portion. The sliding thrust bearing device according to claim 1, wherein the port 2 is formed so as to communicate with the lubricating oil return passage. A first passage connected to the lubricating oil return passage communicating with the first port and a second passage connected to the lubricating oil return passage communicating with the second port are further provided. The sliding thrust bearing device according to claim 2, wherein the lubricating oil is supplied from the lubricating oil supply device to the first passage, and the lubricating oil is recovered from the second passage to the lubricating oil supply device. In a rotary work head that is placed on the table of a machine tool and rotatably attaches the workpiece to be machined.
The spindle housing fixed to the table and
The rotary spindle of the sliding thrust bearing device according to claim 1, wherein the rotary spindle is rotatably supported by the spindle housing.
A spindle motor, which is arranged in the spindle housing and drives the rotary spindle to rotate,
The rotary spindle is also supported in the axial direction by the spindle housing having the bearing member, the sliding member, and the lubricating oil return passage of the sliding thrust bearing device according to claim 1. Characterized rotary work head.

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