CN108778615B

CN108778615B - Rotary table device and machine tool provided with same

Info

Publication number: CN108778615B
Application number: CN201780015709.0A
Authority: CN
Inventors: 矶谷秀逸; 大塚义夫; 外山弘治
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2016-03-09
Filing date: 2017-03-07
Publication date: 2020-11-03
Anticipated expiration: 2037-03-07
Also published as: CN108778615A; JP6686554B2; JP2017159394A; WO2017154886A1; DE112017001226T5

Abstract

A rotary table is rotatably and slidably provided on a support. The piston member is provided so as to be able to apply a pressing force to the rotary table along the rotation axis direction. By this pressing force, a restraining force in the rotational direction against the rotational sliding between the support and the rotary table is generated. The supporter is connected with the piston member by a connecting member. The connecting member is bendable in the direction of the rotation axis, but rigid in the direction of rotation. When pressed, a restraining force is also generated between the piston member and the rotary table.

Description

Rotary table device and machine tool provided with same

Technical Field

An aspect of the invention relates to a rotary table apparatus and a machine tool equipped with the rotary table apparatus.

Background

In large machine tools such as machining centers, there are machine tools including a rotary table for mounting a workpiece or a tool. The rotary table is rotatably mounted and supported on a support as a base. Further, the rotary table may be grasped with respect to the rotation direction on the support member by the urging force of the piston member (for example, see patent document 1).

Documents of the related art

Patent document

Patent document 1: JP-A-2008-114306

Disclosure of Invention

Problems to be solved by the invention

Fig. 6 shows an example of a rotary table device 118 provided in a machining center. As shown in fig. 6, as viewed, the support 122 is disposed at a lower portion, and the rotation table 120 is disposed at an upper portion. The central portion of the support 122 is a rotating base shaft assistance member 140. The inner peripheral cylindrical portion of the rotation table 120 is supported by the rotation base shaft assistance member 140 via a bearing 143, and is rotatable around the rotation base shaft assistance member 140. The direction of rotation is indicated by arrow B.

At a position of an outer peripheral portion of the bearing 122, a slide surface 146 is provided, the slide surface 146 sliding and rotating in the arranged state when the rotary table 120 rotates. Further, between the rotation base shaft auxiliary member 140 of the bearing 122 and the sliding surface 146 of the outer peripheral portion, a piston member 152 that moves up and down by the supply of the working oil is provided between the bearing 122 and the rotation table 120. When the working oil is supplied to the lower working oil chamber 164 of the lower portion of the piston member 152, the piston member 152 moves upward, and when the working oil is supplied to the upper working oil chamber 162 of the upper portion of the piston member 152, the piston member 152 moves downward. The vertical movement range is about 1 mm.

The downward force of the piston member 152 is transmitted to the rib portion 128A of the rotation transmission auxiliary member 128 coupled to the rotary table 120 by the bolt 158, so that the entire rotary tables 120 and 128 are lowered downward.

With the above configuration, the force F indicated by the hollow arrow is transmitted to the rib 128A of the rotation transmission auxiliary member 128 by the downward moving motion of the piston member 152. This force F is transmitted to the rotary table 120 combined with the rotation transmission assisting member 128, and also transmitted as a force F indicated by an outlined arrow to the sliding surface 146 at the position of the outer peripheral portion of the bearing 122. The rotational table 120 is prevented from rotating by a frictional force generated on the sliding surface 146 by the force F transmitted to the sliding surface 146. That is, the rotary table 120 is restricted and held by the support 122.

Further, in the above configuration, the piston member 152 is provided in a state of being unconstrained in the rotational direction with respect to the member on the support member 122 side and the member on the rotational table 120 side. For this reason, when a downward acting force acts on the piston member 152 and frictionally engages with the rib 128A of the rotation transmission auxiliary member 128, the piston member 152 becomes a state of moving integrally with the rotary table 120. That is, in the rotating state of the rotating table 120, the piston member 152 also rotates integrally with the rotating table 120.

In the rotary table device 118, in order to improve the rotation efficiency of the rotary table 120, it is necessary to reduce the friction coefficient between the sliding surface 146 of the bearing 122 and the contact surface of the rotary table 120. On the other hand, in order to improve the clamping force against the external force in the rotation direction of the rotary table 120, it is necessary to increase the friction coefficient between the components. In other words, the compatibility between the high rotation efficiency and the high clamping force of the rotary table 120 is contradictory.

Further, in view of the above points, an aspect of the present invention has been devised, and an object of the present invention is to enable relative rotation between a piston member and a rotary table to be restrained, thereby achieving both high rotational efficiency and high clamping force of the rotary table.

Means for solving the problems

In order to solve the above-described problems, the inventors focused on combining the piston member 152 with the bearing 122 in the rotational direction, wherein in the rotary table device 118 shown in fig. 6, the piston member 152 is in a state of being unconstrained in the rotational direction. Therefore, it is conceived that the rotation of the rotary table 120 in the path of transmitting the force of the piston member 152 to the rotary table 120 is prevented and is used to obtain the clamping force. Aspects of the present invention employ the following methods.

The basic configuration of the rotating table apparatus according to an aspect of the present invention includes: a support serving as a base of the rotating table device; a rotating table provided on a sliding surface formed on the support so as to be rotatable and slidable with respect to the support; and a piston member provided on the rotary table so as to be capable of pressing the rotary table in a rotational axis direction of the rotary table, wherein a restraining force against a rotational sliding between the sliding surface of the bearing and the rotary table in the rotational direction is generated by a pressure applied to the rotary table by the piston member.

The rotating table apparatus further includes a connecting member that connects the supporter and the piston member, the connecting member having a structure that is bendable in a rotational axis direction of the rotating table but has rigidity in the rotational direction, and when pressed against the rotating table by the piston member, a restriction force in the rotational direction of the rotating table is also generated between the pressing portion of the piston member and the rotating table. Here, the fact that the connecting member has rigidity in the rotational direction means that the connecting member does not substantially elastically deform when a load is applied in the rotational direction, and relative rotation between the bearing and the piston member is restricted.

According to an aspect of the present invention, first, when a force in a direction of stopping and restricting rotation by the piston member is applied to the rotating table, a force of stopping and restricting rotation of the rotating table is generated between the rotating table and the sliding surface of the support. Therefore, first, the clamping operation of the turntable on the support is performed.

Further, according to an aspect of the present invention, the clamping operation of the turntable is also performed as follows. In other words, according to an aspect of the present invention, the bearing and the piston member are connected via the connecting member and are coupled to each other in the rotational direction of the rotary table, and the piston member can be displaced in the rotational axis direction. By coupling the piston member to the support member that is the base of the rotary table device and making the piston member a non-rotating member, a biasing force for stopping and restricting rotation of the rotary table is generated between the pressing portions that press the rotary table by the piston member. Therefore, even if the urging force is used, the clamping operation of the rotary table to the support can be performed.

According to an aspect of the present invention, as described above, the action of stopping and limiting the rotation of the rotating table can be performed at two different positions, and a high clamping force on the support can be obtained.

According to an aspect of the present invention, when a force in a direction of restricting rotation by the piston member is not applied between surfaces of the pressing part pressing the rotating table with the above-described piston member, a space between the surfaces of the pressing part becomes a floating state. That is, the bending action of the connecting member returns, and a gap is generated between the pressing portion surfaces. Therefore, the rotary table can be rotated with less sliding resistance, resulting in higher rotation efficiency.

The rotary table apparatus of the aspect of the present invention described above may have the following configuration.

In the above rotary table apparatus, the connection member connecting the supporter and the piston member may include: a first connecting portion connected to the piston member; a second connecting portion connected to the support; and a thin-walled portion provided between the first connecting portion and the second connecting portion and configured to facilitate bending of the connecting member with respect to a rotational axis direction of the rotary table. With this configuration, the relative displacement and movement with respect to the support due to the vertical movement of the piston member can be easily reduced by the smaller resistance due to the thin-walled portion.

The thin-walled portion of the connecting member may have a shape that does not interfere with the support when the connecting member is bent. In this case, the thin-walled portion may be formed in a concave shape in a direction in which the thin-walled portion of the connecting member is separated from the support with respect to the rotational axis direction. By forming the connecting member in such a shape, the connecting member does not interfere with the support when the connecting member is bent, and the connecting member can be used for a long time without being damaged.

The fatigue life improvement method may be applied to the connection member in the above-described rotary table device. By applying the fatigue life improving method, the fatigue life of the connection member can be improved.

The fatigue life improving method may include shot peening. Since shot peening is generally a common method, stable properties can be obtained.

In the above-described rotary table apparatus, when pressed against the rotary table by the piston member, a coefficient of friction between the pressing portion of the piston member and the rotary table may be set larger than a coefficient of friction between a contact surface formed on the bearing and a sliding surface of the rotary table. When the friction coefficient is set in this way, compatibility between higher rotation efficiency and higher clamping force of the rotary table can be satisfactorily achieved.

In the above-described rotary table apparatus, a friction reducing method may be applied between the sliding surface formed on the bearing and the contact surface of the rotary table. When the friction reducing method is applied in this manner, the rotational sliding resistance of the components can be reduced, and higher rotational efficiency can be improved.

The friction reducing material may include a sliding material made of an oil-impregnated resin. By using a sliding material made of an oil-impregnated resin, friction can be effectively reduced and higher rotation efficiency can be facilitated.

It should be noted that the above-described rotary table device may be provided in various machine tools.

THE ADVANTAGES OF THE PRESENT INVENTION

According to the aspect of the invention, the rotary slide portion in which the piston member relatively rotates with respect to the rotary table is provided in the path that transmits the acting force of the piston member to the rotary table, and by preventing and restricting the relative rotation of the piston member, it is possible to achieve a high rotational efficiency and a high clamping force of the rotary table.

Drawings

Fig. 1 is an overall perspective view illustrating a machining center including a rotating table apparatus according to an embodiment of the present invention.

Fig. 2 is a half sectional view showing a rotating table apparatus according to an embodiment of the present invention.

Fig. 3 is a plan view of a connection member according to an embodiment of the present invention.

Fig. 4 is a sectional view taken along line IV-IV of fig. 3.

Fig. 5 is an enlarged view of an arrow V in fig. 4.

Fig. 6 is a half sectional view showing an example of the rotating table device.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the present embodiment, a description will be given of a rotary table device provided in a machining center.

Fig. 1 shows a four-axis machining center 10 including a rotating table arrangement 18. The machining center 10 is a machine tool including three straight axes and one rotation axis. The machining center 10 includes a bed 11, a Z-axis moving column 12, a Y-axis moving body 13, a sleeve spindle 14, a tool 15, an X-axis moving table 16, and a rotary table 20.

The bed 11 is in the shape of a shoulder T and is mounted on a floor surface. The Z-axis moving column 12 is provided on the bed 11 so as to be movable in the Z-axis direction on the bed 11. The Y-axis moving body 13 is provided on the Z-axis moving column 12 so as to be movable in the Y-axis direction with respect to the Z-axis moving column 12. The quill shaft 14 is provided on the Y-axis moving body 13 to be swingable (rotatable) in the a rotation direction with respect to the Y-axis moving body 13. The quill shaft 14 comprises a rotatable shaft. The tool 15 is fixed to the end of the spindle of the sleeve spindle 14 and rotates with the rotation of the spindle.

The X-axis moving stage 16 is provided on the bed 11 so as to be movable in the X-axis direction on the bed 11. The X-axis moving stage 16 includes a rotating mechanism capable of rotating in the B rotation direction. The rotary table 20 is fixed to an upper end portion of the rotation mechanism of the X-axis moving table 16. That is, the rotary table 20 can rotate in the B rotation direction with respect to the X-axis moving table 16. The workpiece W is mounted on the upper surface of the rotary table 20. The X, Y, and Z axes shown in fig. 1 are orthogonal to each other, and the Y axis direction represents a vertically upward direction.

Next, an embodiment of the rotating table device 18 will be described with reference to fig. 2. It should be noted that the illustration of the rotating table device 18 in fig. 1 shows a schematic arrangement state as an image, and specifically the configuration shown in fig. 2. The support 22 serving as the base of the rotary table device 18 shown in fig. 2 corresponds to the X-axis moving table 16 of the machining center shown in fig. 1.

In fig. 2, the rotary table 20 is rotatably supported by the support 22, and the rotation of the rotary table 20 is restricted in such a manner that the rotary table 20 is clamped by the support 22.

The rotary table 20 is composed of a table main body member 24 and a rotation transmission auxiliary member 28. Each of these table main body members 24 and the rotation transmission auxiliary members 28 is annularly arranged around the rotation axis C of the rotating table device 18. The rotation transmission auxiliary member 28 is disposed at a lower surface side position of the table main body member 24. The rotation transmission auxiliary member 28 is joined and joined to the table main body member 24 by a bolt 34.

The support 22 is constituted by a support body member 38, a rotation base shaft assistance member 40, and a cylinder assistance member 42. Each of these

members

38, 40 and 42 is annularly arranged about the rotational axis C of the rotary table device 18. The rotation base shaft auxiliary member 40 is provided at a position of the rotation axis C of the rotating table device 18 and at a position of an inner peripheral side of the support main body member 38. The cylinder assistance member 42 is arranged at an upper surface side position of the support main body member 38 and between the rotation base shaft assistance member 40 of the rotation table 20 and a piston member 52 described later.

Each of the

auxiliary members

40 and 42 is joined and joined with the support body member 38 by bolts or the like. The rotation base shaft auxiliary member 40 is coupled and combined with the support main body member 38 by a fastening device (not shown). The cylinder assistance member 42 is joined and joined to the support main body member 38 by a bolt 39.

In the above-described rotary table 20 and the support 22, the rotation base shaft auxiliary member 40 of the support 22 is formed in a shaft shape, and the rotary table 20 and the support 22 are fitted to the member 40 via the bearing 43, and the rotary table 20 is rotatable. Specifically, the bearing 43 is disposed on the upper end shaft portion 40A of the rotation base shaft auxiliary member 40, so that the rotation of the rotation table 20 can be smoothly performed.

In fig. 2, the upper surface of the support main body member 38 at the lower portion of the right side position of the table main body member 24 is a slide surface 46 that slides and rotates together with the table main body member 24. The rotary table 20 slides and rotates on the sliding surface 46 of the support 22.

The rotation of the rotary table 20 is provided by a power transmission mechanism of a worm gear 48 and a worm wheel 50, the worm gear 48 and the worm wheel 50 being disposed at a lower right position of the rotation transmission auxiliary member 28 as shown in fig. 2. The rotational power of a rotational power source such as an electric motor (not shown) is transmitted to the worm gear device 48.

The piston member 52 is fitted and arranged to an outer peripheral position of the cylinder assistance member 42. As seen in fig. 2, the piston member 52 and the cylinder assistance member 42 are connected by a connecting member 60 located at an upper surface position of both the piston member 52 and the cylinder assistance member 42. The connecting member 60 is joined to the cylinder assistance member 42 by a bolt 55, and is joined to the piston member 52 by a bolt 56. Although the detailed structure of the connecting member 60 will be described later, the connecting member 60 is rigidly coupled in the rotational direction, and is coupled to the rotary table device 18 so as to be flexibly deformable in the rotational axis direction (vertical direction as viewed in fig. 2) C. Therefore, the piston member 52 can be relatively displaced in the rotational axis direction with respect to the cylinder assistance member 42. In the present embodiment, the relative displacement and the amount of movement are about 1 mm.

The piston member 52 is formed so that the cross section is stepped. An upper hydraulic oil chamber 62 and a lower hydraulic oil chamber 64 are formed at a position of the middle level and a position of the lowermost surface of the stepped shape. The position of the intermediate step is the upper working oil chamber 62. The working oil is supplied to the upper working oil chamber 62 through an oil passage 66 formed in the cylinder assistance member 42. Reference numeral 54 denotes a closing stopper of the oil passage 66.

The lowest surface of the piston member 52 is located in the lower operating oil chamber 64. The working oil is supplied to the lower working oil chamber 64 through an oil passage 70 formed in the support main body member 38. It should be noted that the supply and discharge of the upper hydraulic oil chamber 62 and the lower hydraulic oil chamber 64 are switched by a switching valve or the like. In the area of the upper hydraulic oil chamber 62 and the lower hydraulic oil chamber 64 in the present embodiment, the area of the upper hydraulic oil chamber 62 is larger than the area of the lower hydraulic oil chamber 64.

Therefore, according to the above arrangement of the piston member 52, the following force (pressing force) is generated on the piston member 52. First, in a state where the working oil is supplied to the upper working oil chamber 62 and the working oil in the lower working oil chamber 64 is discharged, a force (pressing force) F is generated in the piston member 52 in a downward direction (a direction indicated on the piston member 52 by an outlined arrow in fig. 2). In contrast, when the working oil is supplied to the lower working oil chamber 64 and the working oil in the upper working oil chamber 62 is discharged, an upward force is generated in the piston member 52. The urging force in the downward direction is set to be large in the upward and downward direction due to the difference in area between the upper hydraulic oil chamber 62 and the lower hydraulic oil chamber 64.

Fig. 3 to 5 show the configuration of the connecting member 60. As shown in fig. 3, the connecting member 60 is in the form of a disk with a hollow central portion having an annular cross-sectional shape. As shown in fig. 4 and 5, the inner peripheral portion 60A and the outer peripheral portion 60B in the annular shape are formed in the thick-walled portion 60X when viewed relative to each other, but the intermediate portion 60C between the inner peripheral portion 60A and the outer peripheral portion 60B is formed in the thin-walled portion 60Y. The thin wall portion 60Y is formed by forming a recessed shape between the thick wall portions 60X on the inner and outer peripheries. Therefore, the bending deformation of the connecting member 60 in the rotational axis direction can be easily performed. The concave shape of the thin-walled portion 60Y is formed by cutting.

As described above, the connecting member 60 includes the inner peripheral portion 60A and the outer peripheral portion 60B as the thick-walled portions 60X and the intermediate portion 60C as the thin-walled portion 60Y. This configuration contributes to the characteristics of the connecting member 60, the connecting member 60 being able to bend in the rotational axis direction but having rigidity in the rotational direction. Here, the connecting member 60 having rigidity in the rotational direction means the following state: in this state, when a load in the rotational direction is applied to the connecting member 60, the connecting member 60 rotates without being significantly elastically deformed in the rotational direction. This state means that the amount of elastic deformation of the connecting member 60 in the rotational direction has a rigidity that falls within the allowable amount of deformation in the rotational direction when the design rotational direction maximum load is applied to the connecting member 60.

As shown in fig. 2, the recessed shape of the thin-walled portion 60Y is arranged such that the recessed shape faces the cylinder assistance member 42. Therefore, when the piston member 52 is displaced and moved downward, interference of the connecting member 60 with the upper surface of the cylinder assistance member 42 can be avoided. Therefore, the connecting member 60 can be used for a long time without being damaged.

The connecting member 60 may be bent in the direction of the rotational axis of the rotational table device 18, but the connecting member 60 is made of a steel material according to special requirements for rigidity in the rotational direction and for cost. In the present embodiment, S45C is used. In addition, as the piston member 52 moves and displaces, the connecting member repeatedly bends and displaces, thereby causing fatigue, and thus there is a need to improve fatigue life. Therefore, in the present embodiment, as a means for improving the fatigue life, the shot peening S is applied to the thin wall portion 60Y of the inner peripheral portion and the outer peripheral portion of the connecting member 60. The position where the shot peening S is applied is shown by a broken line in fig. 5. The shot peening S may be applied to the entire surface of the connection member 60 for convenience of machining, but since the machining cost of the shot peening S is proportional to the area, it is preferable to reduce necessary portions from the viewpoint of cost.

As a method for improving the fatigue life of the connecting member 60, there are other methods such as refining quench hardening, and making the material of the connecting member 60a material having high fatigue strength. For example, the material may be baked bearing steel, carbon composite.

As clearly shown in fig. 3 and 5, in the connecting member 60, a plurality of bolt insertion holes 51 into which the bolts 55 are inserted are formed at equal intervals in the inner peripheral portion 60A. Similarly, a plurality of bolt insertion holes 57 into which the bolts 56 are inserted are formed at equal intervals in the outer peripheral portion 60B. In the present embodiment, twenty bolt insertion holes 51 and 57 are formed. As shown in only one position in fig. 3, the bolt insertion holes 51 of the inner peripheral portion 60A and the bolt insertion holes 57 of the outer peripheral portion 60B are located at the same radial position from the center position O.

Returning to fig. 2, the interconnection relationship between the piston member 52 and the rotary table 20 will be described. A rib 28A protruding leftward as shown in fig. 2 is formed on the rotation transmission assisting member 28 of the turntable 20. The right lower end portion 52A of the piston member 52 is disposed in contact with the rib 28A with a predetermined width. Therefore, the force (force F indicated by the hollow arrow) acting downward on the piston member 52 is transmitted to the rotation transmission auxiliary member 28 (the rotary table 20) via the abutment K of the rib 28A and the right lower end portion 52A of the piston member 52, which are two members.

The abutment K of the two

members

28A and 52A is a switchable portion for restricting rotation or allowing rotation depending on whether there is contact between the two

members

28A and 52A. Rotation is restricted in the contact state and rotation is allowed in the non-contact state. That is, since the piston member 52 is brought into a coupled state with the non-rotating cylinder auxiliary member 42 by the connecting member 60, the piston member 52 becomes a relatively rotating portion in a rotating state of the rotating table 20. When a force of contact is exerted on the corresponding abutment K, this force acts to prevent the rotation of the rotary table 20. Therefore, the downward force of the piston member 52 serves as a force for stopping and restricting the rotation with respect to the rotation table 20.

Further, as shown in fig. 2, as a force F indicated by an arrow, a downward force transmitted to the rotary table 20 acts on a sliding surface 46 of the support main body member 38 formed on a right lower surface portion of the table main body member 24 as a force for restricting rotation of the rotary table 20. The first slide member 72 and the second slide member 74 are respectively disposed on the abutment portions M between the slide surface 46 and the lower surface of the table main body member 24. The first slide member 72 is disposed on the slide surface 46, and the second slide member 74 is disposed on the lower surface of the table main body member 24.

In the present embodiment, the friction coefficients of the abutment portion K and the abutment portion M are arranged such that the friction coefficient of the abutment portion K is larger than the friction coefficient of the abutment portion M. Therefore, the abutting portion M is formed by a friction reducing method, and each of the abutting portions K and M is configured as follows. First, in the abutment portion K, the main body portion of the piston member 52 is made of steel. On the other hand, the rotation transmission auxiliary member 28 including the rib portion 28A is made of spheroidal graphite cast iron. Next, in the abutment portion M formed by the friction reducing method, the first sliding member 72 of the sliding surface 46 is made of a sliding material, oil-impregnated resin. The thickness of the first slide member 72 is 1mm to 1.2 mm. The second slide member 74 of the table main body member 24 is made of steel. In addition, the support 22 as a base is made of cast iron. As a result of the above configuration, in the present embodiment, the friction coefficient of the abutment portion K is 0.1 to 0.3, and the friction coefficient of the abutment portion M is 0.02 to 0.05.

Next, the operation of the rotating table apparatus 18 according to the above-described embodiment will be described with reference to fig. 2.

First, in a state where the rotary table 20 on which the workpiece W is placed is rotated, the hydraulic oil is supplied to the lower hydraulic oil chamber 64 below the piston member 52 through the oil passage 70. In this state, the working oil in the upper working oil chamber 62 above the piston member 52 enters a state of being discharged through the oil passage 66. The control of the supply and discharge of the working oil is performed by an oil passage switching valve, not shown. In this state, an upward force is generated in the piston member 52 by the working oil supplied to the lower working oil chamber 64.

By the upward force generated in the piston member 52, the piston member 52 is in a floating state in which the piston member 52 is not in contact with the rotary table 20. That is, the piston member 52 is moved upward by an upward force. This movement is easily performed due to the fact that the connecting member 60 can be bent in the rotational axis direction. Due to this upward movement, the abutment portion K between the piston member 52 and the rib portion 28A of the rotation transmission auxiliary member 28 is in a separated state. Therefore, although the rotary table 20 is placed on the sliding surface 46 of the support body member 38, since a downward force is not applied to the rotary table 20, the rotary table 20 is in a freely rotatable state with a low friction coefficient in which the rotational direction is not restricted with respect to the support 22.

In the freely rotating state of the rotating table 20, the rotating table 20 is rotated by driving a not-shown rotation power source such as an electric motor by means of a rotation transmission mechanism of the worm gear device 48 and the worm wheel 50. Therefore, the workpiece W placed on the rotary table 20 can have a predetermined phase.

Further, in the freely-rotating state of the rotating table 20, the rotating table 20 is rotated and slid on the sliding surface 46 in a state where the rotating table 20 is placed on the sliding surface 46 of the support body member 38. However, since the friction coefficient on the sliding surface 46 is set low, the rotation of the rotating table 20 is performed with high rotation efficiency.

Next, the action of stopping the rotation of the rotation table 20 and restraining and clamping the rotation table 20 to the support 22 will be described. In a state where the rotary table 20 is restrained and clamped by the support 22, the working oil is supplied to the upper working oil chamber 62 above the piston member 52 through the oil passage 66. In contrast, in this state, the working oil in the lower working oil chamber 64 below the piston member 52 is discharged. Therefore, a downward acting force F indicated by an open arrow is generated in the piston member 52 by the working oil supplied to the upper working oil chamber 62.

Due to the downward acting force F generated in the piston member 52, the rib 28A of the rotation transmission assistance member 28 is pressed downward via the abutment portion K. At this time, the operation of preventing and restricting the rotation of the rotation transmission assisting member 28, that is, the rotation table 20 is executed. That is, at the abutment portion K, the non-rotating piston member 52 rotates and comes into sliding contact with the rib 28A in the rotating state by the acting force F, and thus exerts a frictional force that resists rotation. Thus, the rotation of the rotation table 20 is prevented and restrained, and the rotation table 20 is held by the support 22.

In particular, in the present embodiment, the friction coefficient of the abutment portion K is set to be larger than the friction coefficient of the abutment portion M, and the area of the upper hydraulic oil chamber 62 is formed to be larger than the area of the lower hydraulic oil chamber 64. Therefore, a large frictional force for preventing rotation can be generated at the abutment portion K, and the rotary table 20 can be restrained and clamped.

Further, when the rotation transmission assisting member 28 is pushed down by the abutting portion K, the entire rotating table 20 is also moved down. The contact portion M also prevents the rotation of the turntable 20 due to the downward movement of the turntable 20. By this operation, the rotary table 20 is held by the support 22. That is, at the abutment portion M, the rotary table 20 in a rotating state with respect to the non-rotating bearing 22 rotates and makes sliding contact by the acting force F, and thus a frictional force that prevents the rotation is applied. Accordingly, the rotation of the rotation table 20 is prevented and restricted, and the rotation table 20 is clamped by the support 22.

As described above, in the present embodiment, the operation of restricting and clamping the turntable 20 to the support 22 while preventing the turntable 20 from rotating is performed at two positions: at abutments K and M. Therefore, the rotary table 20 can be restrained with a high clamping force.

While the invention has been described with respect to specific embodiments, it may be embodied in various other forms.

For example, in the above-described embodiment, the machining center 10 has been described as a representative example of a machine tool. The rotary table apparatus 18 according to the embodiment of the present invention can also be applied to various machine tools such as a grinding machine.

In addition, in the above embodiment, the position of the abutting portion K is the inner circumferential position, and the position of the abutting portion M is the outer circumferential position, but the opposite arrangement may be adopted.

In addition, although the method for joining the respective components is performed using a fastening tool such as a bolt in the above-described embodiment, other methods such as welding or bonding may be used.

In addition, in the above-described embodiment, the working oil is used as the working pressure for vertically moving the piston member 52, but air may also be used.

The present application is based on japanese patent application (japanese patent application No. 2016-.

Description of the reference numerals

10: machining center

11: lathe bed

12: z-axis moving column

13: y-axis moving body

14: sleeve spindle

15: cutting tool

16: x-axis mobile station (bearing)

18: rotary table device

20: rotary table

22: supporting member

24: table main body member

28: rotary transmission auxiliary member

28A: rib part

30: cover auxiliary member

38: support body member

40: rotary base shaft auxiliary member

42: cylinder auxiliary component

43: bearing assembly

46: sliding surface

48: worm gear device

50: worm wheel

52: piston component

54: closure stop

60: connecting member

60A: inner peripheral portion

60B: outer peripheral portion

60C: middle part

60X: thick wall part

60Y: thin wall part

62: upper working oil chamber

64: lower working oil chamber

66: oil channel

70: oil channel

72: first sliding member

74: second sliding member

B: direction of rotation of the rotary table

C: direction of rotation axis of rotary table

W: workpiece

K: abutting part

M: abutting part

S: shot peening

Claims

1. A rotary table apparatus comprising:

a support as a base of the rotary table apparatus;

a rotating table provided on a sliding surface formed on the support so as to be rotatable and slidable with respect to the support; and

a piston member provided on the rotary table so as to be capable of pressing the rotary table in a rotational axis direction of the rotary table,

wherein a restricting force in a rotational direction against rotational sliding between the sliding surface of the bearing and the rotary table is generated by a pressure applied to the rotary table by the piston member,

wherein the rotating table apparatus further comprises a connecting member connecting the supporter and the piston member,

wherein the connecting member has a structure that is bendable in the rotational axis direction of the rotary table but has rigidity in the rotational direction, and

wherein, when pressed against the rotating table by the piston member, a restraining force in the rotating direction of the rotating table is also generated between the pressing portion of the piston member and the rotating table.

2. A rotary table apparatus as set forth in claim 1,

wherein the connecting member connecting the supporter and the piston member includes:

a first connection portion connected to the piston member;

a second connecting portion connected to the support; and

a thin-walled portion that is provided between the first connection portion and the second connection portion, and that is configured to facilitate bending of the connection member with respect to the rotational axis direction of the rotary table.

3. A rotary table apparatus as set forth in claim 2,

wherein the thin-walled portion of the connecting member has a shape that does not interfere with the support when the connecting member is bent.

4. A rotary table apparatus as set forth in claim 3,

wherein the thin-walled portion is formed in a concave shape in a direction in which the thin-walled portion of the connecting member is separated from the support with respect to the rotational axis direction.

5. A rotating table apparatus according to any one of claims 1 to 4,

wherein a fatigue life improvement method is applied to the connection member.

6. A rotary table apparatus as set forth in claim 5,

wherein the fatigue life improving method comprises shot peening.

7. A rotating table apparatus as claimed in any one of claims 1 to 4 or 6,

wherein a coefficient of friction between the pressing portion of the piston member and the rotary table is set to be larger than a coefficient of friction between the sliding surface formed on the bearing and a contact surface of the rotary table when pressed against the rotary table by the piston member.

8. A rotary table apparatus as set forth in claim 5,

9. A rotating table apparatus as claimed in any one of claims 1 to 4 or 6 or 8,

wherein a friction reducing means is applied between the sliding surface formed on the support and the contact surface of the rotating table.

10. A rotary table apparatus as set forth in claim 5,

11. A rotary table apparatus as set forth in claim 7,

12. A rotary table apparatus as claimed in claim 9,

wherein the friction reducing material formed on the sliding surface on the bearing includes a sliding material made of an oil-impregnated resin.

13. A rotating table apparatus as claimed in claim 10 or 11,

14. A machine tool, comprising:

a rotary table device according to any one of claims 1 to 13.