JPH02224946A - Uniformizing mechanism for thermal displacement of opposing main shaft base - Google Patents

Abstract

PURPOSE:To reduce the difference in the temperatures of both main shaft bases and to improve the work accuracy, by fitting both the end parts of a heat pipe to the relative parts of opposing main shaft bases in the mechanism uniformizing the thermal displacement amount of the opposing main shaft bases of a machine tool, etc. CONSTITUTION:A work W held by main shaft chucks 10, 11 is rotated and turning is performed by the movement in the X axial direction of cutting tool posts 22, 23 and the simultaneous movement in the Z axial direction of main shaft rams 4, 5. The temperatures of main shaft rams 4, 5 rise with the lapse of the operation time. At this time, in the case that both main shafts 8, 9 are rotated by being changed over to both the drivings after being operated for a fixed time by one side driving, for example, the temperatures of the relative positions of main shaft base main bodies 2, 3 and main shaft rams 4, 5 become different. Now the temperature difference of the lower side of the man body 2 of an A main shaft base and that 3 of a B main shaft base is uniformized by a heat pipe 30 and the temperature difference of the upper side by a heat pipe 32, and the difference in the thermal displacement amounts of each part is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a mechanism for making uniform the amount of thermal displacement of opposing parts of each headstock of a machine tool or the like having opposed headstocks.

Conventional technology In a machine tool that chucks both ends of a spindle workpiece with opposing headstocks and performs turning using a tool rest installed on the headstock, both headstocks are not always operated under the same conditions. However, due to heat generated from the main spindle bearing, built-in motor, chuck cylinder, etc., the temperatures of opposing parts of both headstocks will not be the same. Therefore, as shown in the lathe with opposed headstock in Fig. 1, if there is a difference in the amount of thermal displacement due to temperature difference in the dimensions a and b above the spindle center line of the headstock body, the outer diameter dimensional error will be considered as machining accuracy. If the temperature difference between the dimensions a' and b' below the spindle center line causes misalignment in the vertical (X-axis) direction of the amphib shaft center line, the machining accuracy will result in poor cylindricity of the outer diameter. It appears. Furthermore, if misalignment in the horizontal (Y-axis) direction of the center line of the biaxial shaft occurs due to a temperature difference, this will appear as machining accuracy as misalignment during milling.

Conventionally, in order to eliminate the negative effects of these temperature differences on machining accuracy, oil jackets were installed on both headstocks, and the temperature of both headstocks was adjusted by circulating temperature-controlled oil using an oil conditioner, etc. .

Problems to be Solved by the Invention Temperature control using an oil conditioner as described in the prior art has the problem that the structure of the headstock is complicated and an expensive and costly oil conditioner device is required.

The present invention has been made in view of the problems of the conventional technology, and its purpose is to improve machining accuracy by making the temperatures of opposing parts of both headstocks the same. The aim is to provide an inexpensive and simple structure that is possible.

Means for Solving the Problems In order to achieve the above-mentioned object, the thermal displacement equalization mechanism for opposed headstocks of the present invention provides both ends of a heat pipe at opposing parts of each headstock, and This is to reduce the difference in temperature and the difference in thermal displacement.

The different temperatures of the opposing parts of both headstocks due to the temperature rise caused by the operating operation are brought closer to the same temperature by the heat transport operation by the heat pipe, thereby reducing the difference in the amount of thermal displacement of the opposing parts.

Embodiment An embodiment will be explained with reference to FIGS. 1 to 3. The main body 2 of the A headstock and the main body 3 of the B headstock, which are symmetrical with respect to the center, are fixed to both (1!II) on the head 1, facing each other. Square holes 2b and 3b are drilled, and guide grooves in the Z-axis direction in which slide guide surfaces 'la and 3a are formed are cut on four sides of the square holes. , main shaft rams 4 and 5 having square cross-sections and having guide fins in the Z-axis direction that are slidably fitted into the guide grooves via jibs are fitted concentrically, and the main shaft rams 45 are fitted into the main bodies 2 and 3. A fixed NC-driven servo motor 67 allows movement and positioning of each of them synchronously or independently.

A main shaft 8.9 is rotatably supported on the main shaft ram 4.5 by a plurality of bearings, and a chuck 10.11 is attached to the tip of the main shaft with the gripping claws facing each other.
, 9 are rotated by a built-in motor 12.13 built into the spindle ram, and both ends of the shaft workpiece W are gripped by chucks 10.11.

Turret units 1415 are mounted on the main bodies 2 and 3 of the headstock so as to face each other symmetrically with respect to the center,
Frame of the turret unit 16. Vertical (X
A middle stand 18.19 is movably provided on the sliding guide surface in the axial direction, and is moved and positioned by an NC-driven servo motor 2021 fixed to the frame 16.17. The tool rests 22 and 23 are fixed on the middle stand, and the tool rest 222
3 is provided with a turret 24, 25 which can be rotated and indexed on a vertical plane in the X-axis direction, and tool bits 26 and 27 are each removably attached to a tool attachment station of the turret 24, 25.

Furthermore, both ends of a heat pipe 30 are attached to the lower part of the main body 2 of the A headstock and the lower part of the main body 3 of the B headstock.
In addition, heat pipes 31 are provided at the top of main body 2 and the top of main body 3.
Both ends of are attached. Furthermore, both ends of a heat pipe 32 are attached to the main shaft rams 4 and 5, and the heat pipe 32 is made of a flexible material so as to be able to cope with the movement of the main shaft rams 4 and 5 in the Z-axis direction. 32
A thin window 2C in the Z-axis direction is provided on the main body 2.3 for movement.

3C is provided. Both ends of the heat pipe 30.3132, which serve as heat exchange parts, are attached to the main body 23 of the headstock and each part of the spindle rams 4 and 5 so as to increase the heat conduction area. The pipes are covered with insulation. A heat pipe installed in this way has working fluid injected into the pipe.
This working fluid is heated on either the high-temperature side of the main body of the headstock or the main spindle ram, gains heat of vaporization, moves to the low-temperature side due to the evaporated pressure difference, radiates heat here, becomes liquefied, and is liquefied by capillary action in the wick. A known material is used that has the effect of transporting heat from a high temperature side to a low temperature side by circulation returning to the high temperature side, and making the temperature uniform in each part attached at both ends. Since it cannot be specified to one side or the other, it is installed horizontally.

Next, the operation of this embodiment will be explained. The shaft workpiece W, whose both ends are gripped by the main shaft chuck 10.11,
It is rotated by built-in motors 12 and 13, and turning is performed by movement of the tool post in the X-axis direction and synchronized movement of the spindle ram 4.5 in the Z-axis direction. The main shaft rams 4 and 5 contain heat sources such as a main shaft bearing, a built-in motor, and a chuck cylinder, and their temperature increases as the operating time passes. The temperature of the spindle ram is transmitted to the main body 2.3 of the headstock.
temperature increases. At this time, the temperatures at opposing positions of the headstock main body 2.3 and the spindle rams 4, 5 are not necessarily the same even if both spindles are driven and rotate at the same time, and a temperature difference occurs.

Also, if both main shafts are operated for a certain period of time with one side drive and then switched to double drive and rotated at the same rotation,
Obviously, the temperatures at the opposing positions of the headstock body 2.3 and the spindle ram 4.5 differ to a greater extent than in the previous case. Therefore, the main body 2 of the A headstock and the main body 3 of the B headstock
The temperature difference on the lower side is equalized by the heat pipe 30, and the temperature difference on the upper side is equalized by the heat pipe 31.The temperature difference between the main shaft rams 4 and 5 is equalized by the heat pipe 32, and the heat of each part is equalized. The difference in displacement amount becomes smaller.

Effects of the Invention Since the present invention is configured as described above, it produces the following effects.

Since both ends of the heat pipe are attached to opposite parts of the opposing headstock, the temperature difference between the two spindles is reduced, regardless of whether the two spindles are operated under the same conditions or under different conditions. Accordingly, the difference in the amount of thermal displacement decreases, and machining accuracy can be improved.

[Brief explanation of the drawing]

Figure 1 is a view of a lathe with opposed headstock, Figure 2 is A of Figure 1.
3 is a sectional view taken along the line B-B of FIG. 2. 2. Main body of A headstock 3. Main body of B headstock 4.5.
・Main shaft ram 30.31.32...Heat pipe

Claims (1)

[Claims] (1) In machine tools with opposing headstocks, heat pipes (30 to 3
2) A thermal displacement equalization mechanism for opposing headstocks, characterized in that both ends are provided, and the temperature difference between the opposing parts is reduced to reduce the difference in the amount of thermal displacement.