JP2006305669A - Main spindle device of machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent machining accuracy from being considerably deteriorated, even if a bending load is applied to a main spindle, and to know the degree of impact when impact force is applied to tool and main spindle to judge the level of a restoring work. <P>SOLUTION: A ring-shaped member 5 to surround the main spindle 1 is provided at a distal end portion mounted with the tool 7 of a main spindle housing 2. The ring-shaped member 5 is prepared by a member having lower hardness than that of the main spindle 1. The ring-shaped member 5 is arranged with a slight gap between the member 5 and the main spindle 1 so that the main spindle 1 may be in contact with the ring-shaped member 5 when the main spindle 1 is deformed by receiving the bending load. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spindle device of a machine tool, and more particularly to a structure for protecting a spindle against bending load applied to the spindle.

In a spindle device in which the spindle is rotatably supported by a bearing, a bending load is applied to the spindle due to stress during processing. When this bending load is increased, the main shaft is plastically deformed and becomes a runout, which deteriorates the machining accuracy. For this reason, for example, some machining centers perform control such as monitoring the load applied to the spindle motor and the feed shaft and stopping the load when it exceeds a certain range.
For example, in Patent Document 1, when the main shaft comes into contact with a movable member provided at the front end of the main shaft housing due to a bending load applied to the main shaft due to collision or overload of the main shaft and tools, the rotation of the main shaft is immediately stopped and moved. By shearing the bolt supporting the member in stages, the main shaft is prevented from being deformed by absorbing energy when the main shaft collides with the movable member.
JP 11-197979 A

With the configuration of the above-mentioned Patent Document 1, it is possible to absorb the stress applied to the main shaft at the time of collision due to deformation or shearing of the bolt and suppress damage, and to determine the degree of collision by looking at the shearing state of the bolt. However, since the movable member moves, the elastic deformation of the main shaft due to the bending load cannot be suppressed, and it is difficult to maintain the processing accuracy.
In addition, it is necessary to replace the sheared bolt to restore the spindle device, and the restoration work is troublesome, and the bolt is deformed and the movable member is moved even by an overload other than the collision, so that the movable member moves. When the overload is eliminated and the elastic deformation of the main shaft returns to the original state, there is a case where the movable member comes into contact with the opposite side, and in this case, the machining cannot be continued.

  Therefore, in view of such a problem, the present invention does not greatly deteriorate the machining accuracy even when a bending load is applied to the main shaft, and further, when the impact force is applied to the tool or the main shaft, the degree of the impact It is an object of the present invention to provide a spindle device for a machine tool that can easily determine the level of return work.

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a spindle of a machine tool having a spindle for rotating a tool and a spindle housing that rotatably supports the spindle via a plurality of bearings. In the apparatus, a ring-shaped member surrounding the main shaft is fixedly installed at a portion of the main shaft housing that is closer to the front end of the main shaft than the plurality of bearings, and the ring-shaped member is elastically deformed in a direction perpendicular to the axial direction of the main shaft. In this case, the ring-shaped member is arranged so as to contact the ring-shaped member.
With this configuration, when the main shaft is elastically deformed, it comes into contact with the ring-shaped member, so that further deformation of the main shaft can be suppressed, and deterioration of processing accuracy when the main shaft receives a bending load can be reduced. Moreover, plastic deformation of the main shaft can be suppressed.

The invention of claim 2 is characterized in that, in the invention of claim 1, the ring-shaped member is made of a material having a hardness lower than that of the main shaft.
With this configuration, when a collision accident occurs in the spindle or tool due to a program error or the like and a large impact force is applied to the spindle, the trace remains on the ring-shaped member having low hardness. For this reason, it is possible to estimate the impact force applied to the spindle from the trace, and to determine the scale of repair and the location where repair is necessary.

  According to the present invention, further deformation of the main shaft can be suppressed by the ring-shaped member, and deterioration of processing accuracy when the main shaft receives a bending load can be reduced. In addition, by making the hardness of the ring-shaped member lower than that of the main shaft, traces of contact with the main shaft remain, the impact force applied to the main shaft can be estimated from the traces, and the scale of repair and the location where repair is necessary can be determined. It becomes possible.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of a spindle device of a machine tool according to the present invention. 1 is a spindle for rotating a mounted tool 7, 2 is a spindle housing for holding the spindle 1, and 3 is a spindle 1. A bearing for rotatably supporting, 4 is a lid member for closing the tip of the spindle housing 2, 5 is a ring-shaped member attached to the inner side of the lid member 4 so as to surround the spindle 1, and 6 is a tool 7 on the spindle 1. The tool holder for attachment is shown.

A plurality of bearings 3 are provided in the main shaft housing 2, and the main shaft 1 is rotatably supported by these bearings 3. A collet 9 for holding the tool 7 is provided inside the tip of the main shaft 1, and the tool 7 is attached to the main shaft 1 with a tool holder 6 held by the collet 9.
On the other hand, the main shaft 1 has a shaft 10 for moving the collet 9 in the front-rear direction (vertical direction in the drawing), which is the axial direction, to attach and detach the tool holder 6, and this shaft 10 is an upper portion of the main shaft housing 2. Is moved back and forth by a hydraulic device (not shown). The rotation of the main shaft 1 is performed by a servo motor 11.

  The ring-shaped member 5 is fixed by being driven into a ring-shaped concave portion 4a formed on the inner edge of the lid member 4, and is fitted with a tight fit. The ring-shaped member 5 is made of a material softer than the main shaft 1. For example, the main shaft 1 is formed of nickel chrome steel and the ring-shaped member 5 is formed of brass. And the clearance gap between the main axis | shaft 1 and the ring-shaped member 5 is a small space | interval of the grade which the main axis | shaft 1 and the ring-shaped member 5 contact, when a bending load is applied to the main axis | shaft 2 and elastic deformation generate | occur | produces.

  By installing such a ring-shaped member 5, when the bending force (bending moment) is applied from the tool 7 to the main shaft 1 due to cutting force or the like and the main shaft 1 is deformed, the main shaft 1 and the ring-shaped member 5 come into contact with each other. The shaped member 5 has an effect of supporting the bending load and suppressing further bending of the main shaft 1. Therefore, the ring-shaped member can suppress further deformation of the main shaft, can reduce deterioration of processing accuracy when the main shaft receives a bending load, and can also suppress plastic deformation of the main shaft.

  In addition, when the tool 7 or the spindle 1 collides with a workpiece or the like due to a programming error or the like, and the collision between the spindle 1 and the ring-shaped member 5 occurs, there is a trace of the collision with the spindle 1 on the ring-shaped member 5 made of a soft material. Therefore, the impact force applied to the spindle can be estimated based on the size of the trace, and it is possible to determine the scale of repair and the location where repair is necessary.

In the above embodiment, the material of the ring-shaped member 5 is brass. However, the material may be selected from the relationship with the hardness of the main shaft, and may be aluminum or other alloys.
Further, although the ring-shaped member 5 is installed on the lid member 4, the ring-shaped member may be directly attached to the distal end portion of the spindle housing 2.

It is longitudinal section explanatory drawing which shows an example of embodiment of the spindle apparatus of the machine tool which concerns on this invention.

Explanation of symbols

  1 .... main shaft, 2 .... main shaft housing, 3 .... bearing, 4 .... lid member, 5 .... ring-shaped member.

Claims (2)

In a spindle device of a machine tool having a spindle for rotating a tool, and a spindle housing that rotatably supports the spindle via a plurality of bearings,
When a ring-shaped member surrounding the main shaft is fixedly installed in a portion of the main shaft housing that is closer to the front end of the main shaft than the plurality of bearings, the ring-shaped member is elastically deformed in a direction perpendicular to its own axial direction. A spindle device for a machine tool, wherein the spindle device is disposed so as to contact the ring-shaped member. The spindle device for a machine tool according to claim 1, wherein the ring-shaped member is made of a material having a hardness lower than that of the spindle.

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