JPH0561535U - Belleville - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent misalignment between the spindle and the countersunk spring, especially in the countersunk spring used for the spindle of machine tools. [Structure] It is characterized in that a detent means consisting of a protrusion or a recess is provided in a part of a round hole at the center of a flat spring.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a countersunk spring used particularly for a spindle of a machine tool.

[0002]

[Prior Art]

 Belleville springs are dish-shaped in cross section and donut-shaped in plan view. Not only can a large load capacity be obtained in a small space, but the spring characteristics can be changed by stacking multiple sheets. Therefore, it is used in various devices and standardized in JIS B 2706. In machine tools, it is used to clamp a tool on a spindle. FIG. 5 shows a partial cross section of the spindle of the machine tool. In the figure, 1 is a main shaft, which is held by a bearing (not shown) and is rotatable. Reference numeral 2 denotes a drawer, which is arranged inside the main shaft 1 coaxially with the main shaft 1, a collet 4 holding a tool 3 is connected to one end, and a nut 5 is screwed to the other end. The drawer-2 is slidable in the axial direction of the main shaft 1 with the outer periphery of the guide part 6 and the nut 5 provided inside the main shaft 1 as guide surfaces. 7 and the end surface 8 of the nut 5 are pulled upward by the force of a plurality of bevel springs 9 provided between them.

During machining, due to the frictional force generated between the end faces 7 and 8, the belleville spring 9 is integrated with the spindle 1 (hereinafter, the bevel spring 9 and the spindle 1 are collectively referred to as the spindle A). Call it.) Rotate.

[0004]

[Problems to be Solved by the Invention]

 In the above configuration, when the number of rotations of the spindle A is small, if the spindle A is previously provided with a balance at the time of rotation, accurate machining can be performed. However, when the number of rotations of the main shaft A is large, the spiral spring 9 may rotate with respect to the main shaft 1 due to the circumferential acceleration accompanying the start and stop of the main shaft A, and the position may be displaced. Belleville springs are not uniform due to variations in manufacturing. For this reason, when the countersunk spring 9 rotates with respect to the main shaft 1, the main shaft A is out of balance, and vibration occurs during rotation, making it impossible to perform accurate machining. An object of the present invention is to solve the above-mentioned problems and to provide a countersink capable of rotating the main shaft A at a high speed without causing displacement of the main shaft.

[0005]

[Means for Solving the Problems]

 The above-mentioned problems can be solved by providing a rotation stopping means composed of a projection or a depression in a part of the round hole at the center of the flat spring. In addition, for example, the shape of the hole may be an n-sided polygon so as to prevent rotation.

[0006]

[Action]

 Due to the detent means provided in the central hole, the belleville spring will not be displaced with respect to the main shaft.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a plan view of a flat spring 10 showing a first embodiment of the present invention in which the shape of the central hole is hexagonal, and FIG. 1 (b) is a cross-sectional view showing two parts. The main axis 11 is shown by the dotted line. The size of the hole in the flat spring changes when it is compressed. Therefore, even when compressed, the external spring 10 and the main shaft 11 fitted thereto do not interfere with each other, and the external shape of the main shaft 11 and the external spring 10 are prevented from rotating so as not to rotate with respect to the main shaft 11. A gap of 0.1 to 0.5 mm is formed between them.

2 (a), (b) to 4 (a), (b) show a second to fourth embodiment of the present invention, wherein (a) is a plan view and (b) is Is a sectional view. That is, 12 is a round hole provided with a protrusion, 13 is a round hole having a recess, and 14 is an oval shape. Although the shape of the central hole is hexagonal in the first embodiment of the present invention, the same effect can be obtained with a pentagon or octagon.

[0009]

[Effect of the Invention]

 As explained above, the belleville spring of the present invention does not rotate with respect to the main shaft. Therefore, if the spindle A is first balanced, vibrations do not occur during rotation even when the spindle rotation speed is high, and the machining accuracy can be maintained at all times.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention, (a) is a plan view and (b) is a sectional view.

FIG. 2 shows a second embodiment of the present invention, (a) is a plan view and (b) is a sectional view.

FIG. 3 shows a third embodiment of the present invention, (a) is a plan view and (b) is a sectional view.

FIG. 4 shows a fourth embodiment of the present invention, (a) is a plan view and (b) is a sectional view.

FIG. 5 is a cross-sectional view of a spindle portion of a machine tool.

[Explanation of symbols]

 1,11 Spindle 9,10,12,13,14 Belleville spring

Claims (2)

[Scope of utility model registration request] 1. A flat spring, characterized in that a protrusion or a recess is provided in a part of the round hole. 2. The flat spring according to claim 1, wherein the shape of the hole is an n-sided polygon.