JPS5912418B2 - automatic lathe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic lathe.
This invention relates to an automatic lathe that has a function to adjust the tension of a transmission belt that interlocks a main motor and a main shaft.

In conventional automatic lathes, the rear part of the democratic shaft is supported with angular ball bearings to bear the radial and thrust loads, and has a structure that can withstand high-speed rotation. In the case of heavy cutting such as drilling holes, increase the amount of preload on the thrust of the bearing in advance, and adjust it in advance to always maintain it at a constant level to prevent the bearing's balls and rollers from playing due to the load, so-called preload loss. It had been.

And this adjustment is simply set according to the larger load,
Excessive preload was applied even when the load was small, which shortened the life of the bearing, reduced the precision of the product due to heat generation in the spindle, and sometimes caused the risk of fire.

Furthermore, the main shaft that rotates at high speed while holding the workpiece bar is
It is driven by a transmission belt wrapped between the intermediate shaft pulley driven by the main motor and the main shaft, and the transmission belt has a tension pulley that is always strongly pressed in a fixed direction via an elastic device, etc. The main spindle was deflected, resulting in poor rotation accuracy, which had a negative impact on the main spindle, which plays an important role in machining accuracy.

The present invention aims to solve the above-mentioned problems, and one embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows one embodiment of the automatic lathe of the present invention, in which a main motor 3 is attached to a machine frame 1, and drives an intermediate shaft 11 via a motor pulley 5, a drive belt 7, and an intermediate pulley 9. The intermediate shaft 11 is rotatably supported by bearings 13, 13.

The headstock 15 includes a hollow main shaft 1γ (see Fig. 3, the part that clamps the material to be cut is not shown) and a main shaft pulley 1 of integral structure.
9, and the main shaft pulley 19 is driven by a main shaft rotation transmission belt 23 that is wound between a drum pulley 21 fixed to the intermediate shaft 11.

An attachment tool stand 25 is disposed facing the headstock, and the pulleys 27 and 29 are connected to a low speed belt 35 that is wound around a low speed pulley 31 and a high speed pulley 33 that are fixed to the intermediate shaft 11. and high speed side belt 3γ
The rotation is transmitted through the rotating shaft (not shown), and the tool on the attachment tool stand 25 is rotated by switching between high speed and low speed using a clutch device (not shown) provided inside the rotating shaft (not shown).

The tension lever 39 is pivotally attached to a lever shaft 41 fixed to the frame 1, and a tension roller 43 that presses the transmission belt 23 is rotatably pivoted parallel to the transmission belt 23 at one end, and at the other end. As shown in FIG. 2, a tension spring 45 is installed between the frame 1 and the frame 1 so as to be adjustable via an adjustment knob 4T.

A guide bush 49 provided opposite the headstock 15 is attached to a bracket 51 fixedly provided to the frame 1, and a plurality of cutting pies are attached to the bracket 51.
53, 53... are arranged radially with respect to the guide bush 49.

Above the tension roller 43, various cams 55 are provided.
, 55...... camshaft 57 equipped with
is rotatably supported via a plurality of bearings 59 that protrude laterally from the frame 1 and are integrally formed.

A lever 61 located above the cam 55 is provided with a cam follower 3 fixed to its tip, and the lever 61 is connected to a spring 65 tensioned between the bearing portion 59 and the cam 5.
5 to swing around a pivot 67.

The wire outer cylinder 69 has one end fixed to a wire outer cylinder fixing bracket 71 with an outer cylinder fixing screw 73, and the other end extends to a position above the tension spring 45 at the lower end of the tension lever 39. It is fixed to the frame 1 via a wire outer cylinder support block T5.

A wire 77 is slidably inserted into the wire outer cylinder 69. One end of the wire 77 is pivotally supported by the lever 61 via the terminal member 79, and the other end is connected to the tension lever 39 via the terminal member 81. is supported by.

The headstock 15 moves on the sliding bed surface 83 of the frame 1
In this case, bearings, preferably angular ball bearings 85, 85, which support the main shaft 17 in the rotational direction (radial) and axial direction (thrust), tighten the inner ring 85a of the bearing with a holding nut 89 through a spacer 87. This is how it is set up.

Further, a preload adjusting nut 91 is provided to press the outer ring 85b of the bearing via a spherical washer 93.

The preload adjustment nut 91 is screwed onto the headstock 15 and has a roughly cylindrical shape, and a stopper 97 and a catch 99 are provided in a groove 95 on the outer circumferential surface of the nut 91 for adjusting the preload. Two nuts 101 are fitted on the outer periphery of the nut 91 to be fixed at arbitrary positions.

Brass fixed to the headstock 15) 103, 105
Stopper screws 107 and 109 for preload adjustment are screwed into the.

Further, a wire outer cylinder support block 111 is fixed to the headstock 15, one end of which is fixed to the wire outer cylinder 113 via an outer cylinder fixing screw 115, and the other end is fixed to the wire outer cylinder fixing bracket 71. Fixed.

A wire 117 is slidably inserted into the wire outer cylinder 113, one end of the wire 117 is pivoted to the lever 61 via the terminal member 79a, and the other end is supported via the terminal member 119. It is pivotally supported by a clasp 99.

To explain the operation when cutting a workpiece in the above configuration, for example, when machining a finished surface with a small machining allowance on the outer diameter, the drive torque of the spindle is small, and therefore the preload on the bearing is also small. Tension roller 43
The tension of the transmission belt 23 is determined by the tension adjustment knob 4.
7 is adjusted for light cutting through the spring 45, and the preload of the bearing 85 is adjusted by operating the cam 55 to the required amount of preload, the wire 117 is slid by the cam follower 3, and is stopped by the other end. As the ring 99 is rotated, the spherical washer 93 is slightly suppressed or separated by the preload adjustment nut 91 so that the amount of preload on the bearing 85 is maintained.

On the other hand, place a relatively large drill hole in the center of the material to be cut,
If high precision is required for the outer diameter, the cam 55 is used to increase the amount of preload on the bearing.
The spherical washer 93 is pressed by the preload adjustment nut 91 to a position where the amount of preload becomes strong by rotating the stopper 99 via the cam 55 to prevent the transmission belt 23 from slipping due to the cutting torque. wire 7
Rotate the tension lever 39 via the tension lever 7 and
The roller 43 is made to press the transmission belt 23 even more strongly.

Note that the preload adjustment nut 91 is a stopper screw 107.
, 109, so there is no problem of excessive rotation.

As can be understood from the above description of the embodiments, the gist of the present invention is as stated in the claims. Therefore, when the preload adjustment nut is rotated to increase the preload of the main shaft bearing, In conjunction with this, the tension of the transmission belt increases.

Therefore, when there is no need to increase the preload of the bearing, the tension of the transmission belt is not so large (this can solve the conventional problem as described above).

Furthermore, since the rotation of the preload adjustment nut is regulated by the stopper, the preload adjustment nut will not be excessively tightened or loosened.

Note that the present invention is not limited to the above-described embodiments, but can be implemented in other embodiments by making appropriate design changes.

[Brief explanation of drawings]

FIG. 1 is an explanatory overall front view of an automatic lathe showing one embodiment of the present invention, and FIG. 2 is an explanatory right side view thereof. 3 shows a part of a plan view including a partial cross section taken along the line 1--2 in FIG. 1, and FIG. 4 shows a part of the plan view. (Explanation of symbols representing main parts of the drawing), 17...
...Main shaft, 23...Transmission belt, 85...
···bearing.

Claims (1)

[Claims] 1 A main shaft 17 is rotatably provided on a headstock 15 mounted on the machine frame 1 via a bearing 85, and the main shaft 17 is interlocked with the main motor 3 mounted on the machine frame 1 via a transmission belt 23. An automatic lathe is used, and a preload adjustment nut 91 for adjusting the preload of the bearing 85 is screwed onto the headstock 15, and a tension lever 39 that can freely press the transmission belt 23 is pivoted to the machine frame 1. A preload adjustment nut 91 is provided to increase the preload of the bearing 85.
In order to increase the tension of the transmission belt 23 when the transmission belt 23 is rotated, a tension lever 39 and the preload adjustment nut 9 are used.
1, a stopper 97 provided integrally with the preload adjustment nut 91 extends in a direction perpendicular to the main shaft 17, and a stopper screw 107 with which the stopper 97 can abut; 109 to stopper 970
An automatic lathe characterized by being arranged on both sides of the rotation direction so that the position can be adjusted freely.