JP2017170603A - Tool holder and tool machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool holder which eases a load burden exerted on a spindle bearing, and to provide a machine tool.SOLUTION: A tool holder 2 includes: a shank part 20 attached to a spindle 8 supported by a spindle head 9 of a machine tool; a rotary part 30 integrally provided with the shank part 20 and to which a joint tool 10 for friction stir welding (a processing tool) is attached; a bearing mechanism 50 (a bearing part) which rotatably supports the rotary part 30; and a bearing holding part 40 which holds the bearing mechanism 50. The bearing holding part 40 is disposed facing the spindle head 9 and can transmit a load received by the bearing mechanism 50 to the spindle head 9.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a tool holder and a machine tool.

In recent years, friction stir welding has been used as a material joining technique (see Patent Document 1).
In friction stir welding, a rotating welding tool is pressed against an object to be bonded, and the object to be bonded is fluidized by frictional heat and bonded.
In friction stir welding, a welding tool is mounted on a main shaft of a friction stir welding apparatus and is driven to rotate around a rotation axis that intersects the surface of the workpiece. And it moves along the joining part of the surface of a to-be-joined object with a rotation state.

In the friction stir welding apparatus, a dedicated apparatus is frequently used to obtain frictional heat by applying pressure by rotating the welding tool with high torque and moving the axis (tool movement or workpiece movement). On the other hand, a general-purpose machine tool can be substituted if the spindle is rotated, the tool is moved, or the workpiece is moved.
As the welding tool, for example, a tool in which a conical pin is formed coaxially and downward on the lower end surface of a cylindrical holder is used. A stepped shoulder is formed around the pin.
During the friction stir welding operation, the pin is press-fitted into the workpiece and the shoulder is kept facing the surface of the workpiece.

JP 2005-177844 A

As described above, when performing a friction stir welding by attaching a welding tool to a general-purpose machine tool, it is necessary to press the welding tool with a strong force in order to press-fit while rotating the welding tool. For this reason, a strong thrust force is applied to the spindle and the spindle head on which the joining tool is mounted in the rotation axis direction. In general, general-purpose machine tools that perform cutting with a cutting blade do not assume such a strong thrust force. May cause damage.
Providing a tool holder and a machine tool that can alleviate the load burden on the spindle bearing, which may occur not only in friction stir welding but also in other forms of cutting. Was desired.

  The objective of this invention is providing the tool holder and machine tool which can ease the load burden concerning a main shaft bearing.

  A tool holder according to the present invention includes a shank portion that is attached to a spindle supported by a spindle head of a machine tool, a rotating portion that is provided integrally with the shank portion and is capable of attaching a processing tool, and the rotating portion. A bearing portion that rotatably supports and a bearing holding portion that holds the bearing portion. The bearing holding portion is disposed to face the spindle head and can transmit a load received by the bearing portion to the spindle head. It is characterized by being.

In the present invention, when the shank portion mounted on the main shaft is driven by the main shaft, the rotating portion and the processing tool mounted on the rotating portion are rotated. Processing can be performed by bringing the rotating processing tool into contact with the workpiece to be processed.
Here, due to the reaction force from the workpiece, a heavy load is generated in the rotating part on which the machining tool is mounted. This load is transmitted to the bearing holding part via the bearing part, and is transmitted to the spindle head to be released. be able to. For this reason, it can avoid that a heavy load burden is applied to the main shaft, and the main shaft bearing can be kept safe.

  In the tool holder of the present invention, the bearing holding portion has a contact member capable of contacting the end surface of the spindle head on a surface facing the spindle head, and the contact member is arranged around the spindle. It is desirable that a plurality are arranged in the direction.

In the present invention, the load from the bearing portion can be transmitted to the spindle head via the contact member.
Further, the contact area can be reduced as compared with the case where the contact member is divided into a plurality of parts and is continuous over the entire circumference, and high heat generated by the processing tool can be prevented from being conducted to the spindle head.

In the tool holder according to the aspect of the invention, it is preferable that the contact members are evenly arranged in the circumferential direction around the main shaft.
In this invention, the circumferential balance of the load with respect to a spindle head can be ensured because the contact members are evenly arranged in the circumferential direction.

In the tool holder of the present invention, it is desirable that a refrigerant passage is formed in the rotating portion.
In the present invention, heat conducted from the machining tool to the rotating part can be cooled by the refrigerant passing through the refrigerant passage, and conduction of heat to the bearing part or the spindle head can be suppressed. Furthermore, tool cooling after the end of bonding is possible, and the time until resumption of bonding can be shortened.

In the tool holder of the present invention, it is preferable that the processing tool is a welding tool for friction stir welding, and the bearing portion has a thrust bearing.
In the present invention, friction stir welding can be performed by pressing a rotating welding tool against a workpiece to be processed.
Here, due to the reaction force from the object to be joined, a strong thrust force is generated in the welding tool and the rotating part, but this thrust force is transmitted to the bearing holding part via the thrust bearing and can be released to the spindle head. . For this reason, it can avoid that a strong thrust force is applied to the main shaft, and the main shaft bearing can be kept safe.

The machine tool of the present invention is characterized in that the above-described tool holder of the present invention is mounted, and a detent is formed between the spindle head and the bearing holding portion.
According to the machine tool of the present invention, the same effect as the above-described tool holder of the present invention can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the tool holder and machine tool which can ease the load burden concerning a main shaft bearing can be provided.

The side view which shows one Embodiment of this invention. Sectional drawing which shows the internal structure of the said embodiment. The top view which shows the shank part side of the said embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2, a friction stir welding tool 1 according to this embodiment is mounted on a main shaft 8 supported by a main shaft head 9 of a machine tool, and performs friction stir welding of an object 7 to be joined.

As the machine tool of the present embodiment, various types capable of rotating the spindle 8 and relatively moving the spindle 8 with respect to the workpiece (in the present embodiment, the workpiece 7 but the workpiece to be cut when used as a machine tool) are used. The spindle head 9 or the friction stir welding tool 1 can be moved to any position with respect to the workpiece 7.
In the machine tool, the spindle 8 is rotatably supported by the spindle head 9 and is driven to rotate by a motor (not shown) installed on the spindle head 9.

The friction stir welding tool 1 includes a welding tool 10 for friction stir welding and a shank portion 20 for mounting on the main shaft 8. Further, the friction stir welding tool 1 includes a rotating unit 30 that connects the welding tool 10 and the shank unit 20, a bearing holding unit 40 that is connected to the spindle head 9, and a rotating unit 30 that is installed in the bearing holding unit 40. A bearing mechanism 50 is rotatably supported.
Here, the joining tool 10 is a processing tool of the present invention, the bearing holding portion 40 is a bearing holding portion of the present invention, and the bearing mechanism 50 is a bearing portion of the present invention.
The tool holder 2 of this invention is comprised by these shank parts 20, the rotation part 30, the bearing mechanism 50 which is a shaft plum part, and the bearing holding part 40 which is a bearing holding part.
In this embodiment, the friction stir welding tool 1 is configured by mounting the welding tool 10 for friction stir welding on the tool holder 2.

The welding tool 10 is a tool for friction stir welding, and has a shoulder 12 and a pin 13 at the tip of the tool body 11.
When the welding tool 10 is pressed against the workpiece 7 in a rotating state, the pin 13 at the tip is pressed into the workpiece 7 while heating and melting the material of the workpiece 7, and the joint of the workpiece 7 is joined. Can be melt bonded.

The shank part 20 is a 7/24 taper shank (BT type) for automatic tool change defined in JISB6339-2: 2011, and is detachable from the spindle 8 based on JISB6340-2: 2011 corresponding to the same standard.
The shank portion 20 has a tapered cone 21 and a pull stud 22, and is pulled into the tapered hole of the main shaft 8 by the pull stud 22. Then, the taper cone 21 is in close contact with the inner surface of the taper hole, so that the rotational force can be transmitted while being held by the main shaft 8.

The rotating unit 30 has a cylindrical shaft 31. The main shaft 8 side of the shaft 31 is continuously the shank portion 20 described above.
A chuck 32 for fixing the joining tool 10 is formed on the joining tool 10 side of the shaft 31.
The chuck 32 is formed in a cylindrical shape that can accommodate the tool main body 11 of the joining tool 10 coaxially, and a plurality of bolts 321 are installed in the cylindrical portion toward the center.
When the tool main body 11 is mounted, the tool main body 11 is pressed against the cylindrical bottom of the chuck 32 to receive a thrust force. Furthermore, the tool main body 11 is tightened with the bolts 321 so that the joining tool 10 is prevented from rotating with respect to the shaft 31.

The bearing holding part 40 has a cylindrical case 41.
As shown in FIG. 3, the contact member 42 is fixed to the end surface of the case 41 on the main shaft 8 side along the outer peripheral edge by a bolt 421. A positioning member 43 is fixed by a bolt 431 at a part of the interval between the contact members 42.

The contact members 42 are arc-shaped members, and four are arranged at equal intervals.
The contact member 42 can contact the innermost portion of the end face of the spindle head 9 with the friction stir welding tool 1 attached to the spindle 8. In this state, the contact member 42 does not interfere with the main shaft 8.

The positioning member 43 is disposed between the pair of contact members 42 and is formed so as to protrude from the contact members 42.
The spindle head 9 is formed with a recess 432 (see FIG. 1) in which the positioning member 43 can be accommodated. When the friction stir welding tool 1 is mounted on the spindle 8, the positioning member 43 is fitted into the recess 432. As a result, the bearing holding portion 40 is prevented from rotating at an intended angular position with respect to the spindle head 9.

  The bearing mechanism 50 is configured by installing a pair of angular roller bearings 51 and 52 back to back. Angular roller bearings 51 and 52 hold a large number of rollers in a direction in which each rotation axis obliquely intersects with the rotation axis of rotation unit 30. Such angular roller bearings 51 and 52 have a function as a thrust bearing that receives a load along the center axis and a function as a radial bearing that receives a load in a direction intersecting the center axis.

  In the present embodiment, the bearing mechanism 50 is the angular roller bearings 51 and 52, but may be replaced with a ball-type angular bearing. However, roller bearings can withstand high loads. Further, instead of the angular bearing, a thrust bearing and a radial bearing may be combined and replaced. However, the angular bearing can save space. Further, it is not essential to form a pair like the angular roller bearings 51 and 52, and a thrust bearing that can bear at least a load along the axial direction from the joining tool 10 side to the main shaft 8 side from the rotating portion to the bearing holding portion. It suffices to have the function.

As shown in FIG. 2, the friction stir welding tool 1 of the present embodiment is formed with a refrigerant passage 60 around the bearing holding portion 40 and the rotating portion 30.
The refrigerant passage 60 includes an introduction portion 61 formed in a part of the contact member 42, a bearing holding portion passage 62 and an annular groove 63 formed in the case 41, and a movable portion passage 64 formed in the shaft 31. And a discharge unit 65.
The introduction portion 61 is in communication with the bearing holding portion passage 62, and the bearing holding portion passage 62 is in communication with the annular groove 63. The annular groove 63 goes around the inner peripheral surface of the case 41, and the movable portion passage 64 communicates with the annular groove 63 and the bearing holding portion passage 62 regardless of the angular position of the shaft 31. The discharge part 65 is opened on the outer peripheral surface of the shaft 31 at the end of the shank part 20.

Therefore, if the friction stir welding tool 1 is attached to the main shaft 8 and the refrigerant supply nozzle (not shown) on the main shaft head 9 side is set to be connected to the introduction portion 61, it is supplied to the introduction portion 61. The refrigerant is discharged from the bearing holding portion passage 62 through the annular groove 63 and the movable portion passage 64 from the discharge portion 65.
By passing the coolant, the heat conducted from the joining tool 10 to the rotating part 30 is cooled, and is prevented from being conducted to the bearing mechanism 50 and the bearing holding part 40, or the spindle 8 and the spindle head 9. . Note that air (air cooling) can be used as the refrigerant. As long as it is a fluid that conducts heat, coolant (water cooling) or other materials may be used. When coolant is used as the coolant, it is necessary to consider the coolant flow path so as not to affect the lubrication of the bearing portion.

In the present embodiment, the friction stir welding tool 1 is mounted on the machine tool by connecting the shank portion 20 to the main shaft 8. With the mounting, the bearing holding portion 40 is brought into contact with the end surface of the spindle head 9 by the contact member 42 and is positioned by the positioning member 43.
In this state, the spindle head 9 and the friction stir welding tool 1 are moved so that the welding tool 10 faces the workpiece 7. Then, by rotating the main shaft 8, the shank portion 20, the rotating portion 30, and the welding tool 10 are integrally rotated. Then, the friction stir welding can be performed by moving the welding tool 10 after press-fitting it into the workpiece 7.

  Here, due to the reaction force from the workpiece 7, a strong thrust force is generated in the welding tool 10 and the rotating unit 30. This thrust force is transmitted to the bearing holding portion 40 via the bearing mechanism 50 having the function of a thrust bearing, and can be released from the contact member 42 to the spindle head 9. For this reason, it is possible to avoid applying a strong thrust force to the main shaft 8, and the main shaft bearing that supports the main shaft 8 in the main shaft head 9 can be kept safe.

In the present embodiment, the thrust force from the joining tool 10 can be transmitted to the spindle head 9 via the contact member 42.
At this time, since the contact members 42 are evenly arranged in the circumferential direction, a circumferential balance of the thrust with respect to the spindle head 9 can be ensured.
Further, the contact area with the spindle head 9 can be reduced as compared with the case where the contact member 42 is divided into a plurality of parts and is continuous over the entire circumference. For this reason, it can suppress that the high heat of the joining tool 10 is conducted to the spindle head 9.

  In this embodiment, the heat conducted from the joining tool 10 to the rotating part 30 can be cooled by the refrigerant passing through the refrigerant passage 60, and the heat from the bearing mechanism 50 to the bearing holding part 40 or the spindle head 9 can be reduced. Conduction can also be suppressed.

Note that the present invention is not limited to the above-described embodiments, and modifications and the like within a scope in which the object of the present invention can be achieved are included in the present invention.
As described above, the joining tool 10 and the shank portion 20 may be existing ones, and these may be formed continuously from the shaft 31 or may be connected separately.
If the function as a bearing part of this invention is acquired also about the bearing mechanism 50, the structure can be changed suitably.

  The arrangement and dimensions of the abutting member 42 may be appropriately designed in the implementation, and it is desirable to reduce the contact area with respect to the spindle head 9 as long as there is no problem in strength. The arrangement of the abutting member 42 is preferably point-symmetric with respect to the center of the main shaft 8, but it is not essential, and an unbalance that can ensure a load balance is acceptable.

The refrigerant passage 60 may be formed so that the bearing holding portion passage 62 circulates widely around the case 41 so that the bearing mechanism 50 can be cooled from the outside.
As the refrigerant passage 60, a passage penetrating the center of the shank portion 20 may be provided, and a refrigerant supplied through the center through of the main shaft 8 may be used.
In the said embodiment, the friction stir welding tool 1 was comprised by using the welding tool 10 for friction stir welding as a processing tool, and attaching this to the tool holder 2 based on this invention. However, the processing tool to be mounted on the tool holder 2 of the present invention is not limited to the welding tool 10 for friction stir welding, and a cutting tool is configured by mounting other processing tools such as for cutting. May be.

  The present invention relates to a tool holder and a machine tool, and can be used when performing machining with a large load on a spindle bearing using a general-purpose machine tool.

  DESCRIPTION OF SYMBOLS 1 ... Friction stir welding tool, 2 ... Tool holder, 10 ... Joining tool which is a processing tool, 11 ... Tool main body, 12 ... Shoulder, 13 ... Pin, 20 ... Shank part, 21 ... Taper cone, 22 ... Pull stud, 30 Rotating part, 31 ... Shaft, 32 ... Chuck, 321 ... Bolt, 40 ... Bearing holding part, 41 ... Case, 42 ... Abutting member, 421 ... Bolt, 43 ... Positioning member constituting detent, 431 ... Bolt, 432... Recessed part constituting a detent, 50... Bearing mechanism as a bearing part, 51 and 52. Angular roller bearing, 60. Refrigerant passage, 61 .. introduction part, 62. Movable portion passage, 65 ... discharge portion, 7 ... object to be joined, 8 ... main shaft, 9 ... main shaft head.

Claims (6)

A shank portion mounted on the spindle supported by the spindle head of the machine tool;
A rotating part provided integrally with the shank part and capable of mounting a processing tool;
A bearing portion that rotatably supports the rotating portion;
A bearing holding portion for holding the bearing portion,
The tool holder, wherein the bearing holding part is disposed to face the spindle head and can transmit a load received by the bearing part to the spindle head.   The bearing holding portion has a contact member that can contact the end surface of the spindle head on a surface facing the spindle head, and a plurality of the contact members are arranged in the circumferential direction around the spindle. The tool holder according to claim 1, wherein:   The tool holder according to claim 2, wherein the contact members are evenly arranged in the circumferential direction about the main shaft.   The tool holder according to any one of claims 1 to 3, wherein a refrigerant passage is formed in the rotating part. The processing tool is a welding tool for friction stir welding,
The tool holder according to any one of claims 1 to 4, wherein the bearing portion includes a thrust bearing. The tool holder according to any one of claims 1 to 5 is mounted,
A machine tool characterized in that a detent is formed between the spindle head and the bearing holding portion.

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