JPH0236680Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in the cooling structure of a feed screw of a machine tool.

[Conventional technology]

For example, a feed screw of a machine tool such as an NC lathe is used to move a movable member such as a carriage in the feed direction with high precision and smoothly. However, if the feed screw is used for a long time, heat will be generated from the moving parts screwed into the feed screw and the bearings that support the feed screw, causing thermal deformation and making it impossible to perform high-precision machining. It was hot.

Therefore, a cooling structure for a feed screw as shown in FIG. 2 has been proposed. That is, a through hole 1a is bored in a feed screw made of a hollow ball screw 1, and a cooling liquid is flowed through the through hole 1a to cool the heat sources such as the moving member 2 and the bearings 3 and 4. In this case, the bearings 3 and 4 are attached to the fixed parts 5 at both left and right ends of the hollow ball screw 1 via housings 6 and 7, and the outer rings are connected to the outer rings by adapters 8 and 9, and the collars 12, 13, and 14 by nuts 10 and 11, respectively. ,15
The inner ring is tightened through the Further, a drive pulley 16 is fixed to the outside of the right bearing 3 by a shuppan ring 17, and is configured to rotate the ball screw 1. On the other hand, a coolant inflow joint 18 is screwed onto the case 19 on the outside of the left bearing 4, and the coolant flows through the through hole 1a of the hollow ball screw 1 described above and into the radial direction in front of the right bearing 3. It is configured to be discharged from a discharge joint 20 provided in the housing 6 through the hole 1b.

[Problem that the invention attempts to solve]

However, in this cooling structure, oil seals 21, 22, and 23 are provided on the outside of the left bearing 4 and in front of the right bearing 3, respectively, in order to prevent leakage of the cooling fluid. Since the lip portions at the tips of 22 and 23 are in close contact with the hollow ball screw 1, there is a problem in that they become a new heat source and impair the cooling effect.

The present invention has been proposed in view of the above points, and an object of the present invention is to provide a cooling structure for a feed screw that does not have a sealing part and has a large cooling effect.

[Means for Solving the Problems and Their Effects] In order to solve the above problems, the present invention provides a hollow ball screw whose both ends are supported on a fixed part and a through hole is drilled therein, and one of the hollow ball screws. A rotated member that is attached to the shaft end and has a through hole that communicates with the through hole of the hollow ball screw and is supported by the fixed part and has a small heat transfer coefficient, and a rotated member that is attached to the other shaft end of the hollow ball screw and has a through hole communicating with the through hole of the hollow ball screw. A mounting member having a through hole communicating with the through hole and having a small heat transfer coefficient, the rotated member, and a rotary joint having a rotation supply shaft in each end through hole of the mounting member. Features.

By adopting the above configuration, it is possible to obtain a cooling structure for the feed screw without a seal part, and also to provide a rotating member made of a material with a small heat transfer coefficient between the rotary joint, which is a heat source, and the hollow ball screw. Since the driving pulley and the holding member which is the mounting member are interposed, it is possible to prevent the heat of the rotary joint from being transmitted to the feed screw.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional front view of the present invention. Components that are the same as those in FIG. 2 are designated by the same reference numerals, and explanations thereof will be omitted.

The hollow ball screw 1 with the through hole 1a is
It is pivotally supported by fixed parts 5 on both sides via bearings 3 and 4,
Rotary joints 24 and 25 are connected to both ends thereof.

A ball screw is provided between the bearings 3 and 4, and the moving member 2 is screwed onto the ball screw so as to be movable left and right. Bearing 3 on the right side is
The outer ring is tightened by an adapter 8a, and the inner ring is tightened by a nut 10a via a collar 12a. Also, the left bearing has its outer ring tightened by an adapter 9a and its inner ring tightened by nuts 11a and 11b.

A housing 26 is fitted into the fixed part 5 outside the right bearing 3, and a bearing 27 is inserted into the housing 26, and the hollow ball screw 1 is connected to the housing 26 through a bearing 27.
A drive pulley 28 is provided which is a rotated member that is fitted into the drive pulley and made of a material with a small heat transfer coefficient. The drive pulley 28 is tightened from the left and right by flanges 29 and adapters 30.

On the other hand, on the outside of the left bearing 4, a holding member 3, which is a mounting member made of a material with a small heat transfer coefficient, is provided between the adapter 9a and the hollow ball screw 1.
1 is interposed and tightened by a flange 32.

The holding member 31 is connected to the inflow rotary joint 25 for the coolant, and the coolant passes through the through hole 1a of the hollow ball screw 1 described above, and flows to the right side of the drive pulley 28, which is also connected to the discharge rotary joint 24. It is configured to be ejected through the clamping adapter 30.

With this configuration, power is transmitted from a motor (not shown) to the drive pulley 28 via the timing belt, the hollow ball screw 1 rotates, and the moving member 2 screwed into the ball screw 1 moves left and right. Become. In the case of the present invention, heat generated during this movement and heat generated from the bearings 3 and 4,
That is, since there is no heat generation in the sealed portion, the inside of the hollow ball screw 1 is effectively cooled by the circulation of the cooling liquid. In addition, the rotary joints 24 and 25, which are heat sources, are provided at the extreme ends of the hollow ball screw to enhance the heat dissipation effect.
4, 25 and the hollow ball screw 1 are provided with the drive pulley 28 and the holding member 31, each made of a material with a small heat transfer coefficient, so that the heat generated by the rotary joints 24, 25 is transferred to the hollow ball screw 1. can be prevented from being transmitted.

[Effect of idea]

As explained above, the present invention eliminates any sealing parts that come into close contact with the hollow ball screw, and prevents the heat generated from the rotary joints at both ends of the hollow ball screw from being transmitted to the hollow ball screw.
Since a member with a small heat transfer coefficient is installed between the joint and the hollow ball screw, it is possible to obtain a cooling structure for the feed screw that is superior to the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view showing an embodiment of the feed screw cooling structure of the present invention, and FIG. 2 is a sectional front view showing a conventional feed screw cooling structure. 1... Hollow ball screw, 2... Moving member, 3,
4... Bearing, 5... Fixed part, 24, 25... Rotary joint, 26... Housing, 27...
... bearing, 28 ... drive pulley, 31 ... holding member.

Claims (1)

[Scope of utility model registration request] A hollow ball screw that is supported at both ends on the fixed part and has a through hole drilled therein, and a through hole that is attached to one shaft end of the hollow ball screw and communicates with the through hole of the hollow ball screw, and is supported on the fixed part. A rotated member with a small heat transfer coefficient; a mounting member with a small heat transfer coefficient that is attached to the other shaft end of the hollow ball screw and has a through hole communicating with the through hole of the hollow ball screw; and the rotated member with a small heat transfer coefficient. and a rotary joint having a rotating supply shaft in each end through-hole of the mounting member.