JPH09257102A - Damper with coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damper installed simply without the increased of total length, which can attenuate the vibration transmitted to a shaft efficiently. SOLUTION: An outer wheel 5 having a prescribed mass is installed rotatably for a nearly ciylindrical inner wheel 6 through a bearing member 7 also a buffer member 8 is interposed in the clearance between the inner wheel 6 and the outer wheel 5 and a damper member 3 for attenuating the vibration transmitted to the inner wheel 6 and a coupling member 4 installed inside this damper member 3 integrally and for connecting both shafts 1, 2 by that the main shaft 1 of a servomotor M and a ball screw shaft 2 are fixed to the inner wheel 6 of the damper member 3 respectively are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper attached to a rotary shaft, and more particularly to a damper attached to a main shaft of a motor.

[0002]

2. Description of the Related Art Numerically controlled machine tools (NC machine tools) are
It is a machine tool that automatically controls some movements using numerical values that specify the moving position and speed of tools, and numerical information that is composed of symbols that indicate the type of movement. It makes it easy to create complicated shapes that are difficult to manufacture with high precision, and it also plays a major role in automating processing plants that produce a wide variety of small quantities, saving labor, reducing processing costs, and shortening processing time.

In high speed and high precision machining equipment such as this NC machine tool, generally, a ball screw shaft is screwed onto a ball nut screw mounted on a table on which a work is placed, and the ball screw shaft is used as a servo motor. The workpiece is positioned at a predetermined accurate position to be processed by rotating the table by moving the table by, for example. Such position control is performed, for example, in the three axial directions of the X, Y, and Z axes.

[0004]

By the way, in high-speed and high-precision machining equipment, the following accuracy of the servomotor used for position control in the NC axis direction such as the X, Y, and Z axes that determines the accuracy, that is, the actual command It is necessary to minimize the error in the movement of.

However, if the servo gain for positioning in the servo circuit is increased in order to improve the followability of the servo motor, on the other hand, the motor becomes sensitive and vibrates by itself (high frequency vibration). As a result, the servo gain cannot be raised above a certain value, and there is a certain limit in the tracking accuracy.

On the other hand, as shown in FIGS. 2 to 4, a method of mounting a damper for attenuating vibration on the rotary shaft can be considered.

In FIG. 2, the main shaft 1 of the motor M is extended to the side opposite to the output side, and a damper 23 is attached via a coupling 22 for connecting to the end of the main shaft 1. The output side of the main shaft 1 has another coupling 2
It is connected to the ball screw shaft 2 by 1. But,
In FIG. 2, the motor M is used to detect the rotational position.
There is a drawback that it cannot be attached to a servomotor with a rotary encoder that is directly connected to the spindle 1.

Further, in FIG. 3, the damper 23 is directly attached to the main shaft 1 itself of the motor M through the coupling 22, but it is difficult to install unless the main shaft 1 is a long motor. No. 4 is a ball screw shaft 2 which is individually designed and is extended by an amount corresponding to the damper 23 and is attached. However, since the damper 23 is not directly attached to the main shaft 1 of the motor M, a damping effect on the motor itself is provided. It gets smaller.

Further, since the ones shown in FIGS. 2 to 4 are each composed of two couplings and a damper, the number of parts is large, and moreover, the total length in the axial direction is always long, so that it is applied. If you can not secure a predetermined space in a place, you can not install the damper,
On the other hand, even if they are attached, the same attachment method cannot be adopted depending on the size of the space to which they are applied, and even within the same equipment, a dedicated design is required for each.

An object of the present invention is to provide a damper which can be easily mounted without increasing the overall length and which can efficiently damp the vibration transmitted to the shaft.

[0011]

The present invention for achieving the above object is specified as follows for each claim. The invention according to claim 1 is a damper with a coupling in which a coupling member for connecting two shafts is integrally provided inside the damper member for damping the vibration of the vibration system. .

According to a second aspect of the present invention, an outer ring having a predetermined mass is rotatably provided to a substantially cylindrical inner ring via a bearing member, and a buffer member is interposed in a gap between the inner ring and the outer ring. A damper member mounted on the inner ring of the damper member, and a damper member for damping the vibration transmitted to the inner ring, and two shafts arranged integrally inward of the damper member and arranged in series to the inner ring of the damper member. A damper with a coupling including a coupling member for connecting two shafts.

According to a third aspect of the present invention, in the damper with a coupling according to the second aspect, one of the two shafts is a main shaft of a motor as a rotation driving means.

According to a fourth aspect of the present invention, in the damper with a coupling according to the second aspect, the inner ring is provided with a disc portion which is orthogonal to the axis and protrudes outward, and the disc portion is provided. It is characterized in that it is housed in a groove formed inside the outer ring.

According to a fifth aspect of the present invention, in the damper with a coupling according to the second aspect, the buffer member is a silicon gel.

According to a sixth aspect of the present invention, in the damper with a coupling according to the second aspect, the coupling member is integrally formed inside the inner ring and extends from both shaft ends toward a shaft center. Two inner conical surface parts with smaller diameter,
An outer conical surface portion that contacts each of the inner conical surface portions is formed, and two wedge members having end surfaces with a small diameter that are arranged to face each other are provided, and both wedge members are moved closer to each other in the axial direction. Thus, the two shafts are fixed to the inner ring, respectively.

[0017]

According to the present invention, the following effects can be obtained for each claim. In the invention described in claim 1 or 2, the vibration transmitted to the shaft can be efficiently damped, and at the same time, the connection of the two shafts and the mounting of the damper with the coupling can be collectively performed by one component. Therefore, without increasing the axial total length before mounting the damper member,
It is possible to simply and quickly install various biaxial connection points of various equipment without requiring special modification.

Further, in the invention described in claim 3, since the vibration induced in the motor can be efficiently damped, the gain of the motor can be dramatically increased, and the accuracy of the motor operation can be greatly improved. Can be made. Further, since the positional relationship between the damper member and the motor becomes constant, there is an advantage that the damping effect is stable and the desired accuracy can be surely obtained.

Further, in the invention described in claim 4, it is possible to expand the contact area between the outer ring and the inner ring which are in contact with each other via the cushioning member, and to set the viscous damping coefficient of the damping vibration system by the damper member to be large. .

Further, in the invention according to claim 5, the cushioning member has high viscosity and heat resistance.

According to the sixth aspect of the present invention, when the wedge members are moved closer to each other in the axial direction, the wedge members are fitted in the axial direction between the outer surfaces of the two shafts and the inner conical surface portion of the inner ring. By pressing the contact surfaces against each other, the two shafts can be easily fixed and connected to the inner ring while maintaining the coaxiality.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a half cross-sectional view showing a state in which a damper with a coupling according to an embodiment of the present invention is attached to a connecting portion of a main shaft of a motor. The members common to those shown in FIGS. 2 to 4 are designated by the same reference numerals.

As shown in FIG. 1, the damper with a coupling according to this embodiment is a damper member 3 for damping vibration.
A coupling member 4 connecting the two shafts is integrally provided in the damper member 3 inward.

The damper member 3 has a substantially cylindrical inner ring 6
And an outer ring 5 rotatably provided to the inner ring 6 via a bearing member 7 and having a predetermined mass. As the bearing member 7, for example, a radial ball bearing is used, but an angular type may be used, or another radial bearing may be used.

The outer ring 5 is composed of a pair of substantially disk-shaped housings 5a and 5b which are joined together by bolts 10 in the middle, and a ring-shaped groove portion 9 is formed between them. . The outer ring 5 can be adjusted by changing the outer diameter of the outer ring 5 to change the mass of the damping vibration system by the damper member 3, that is, the inertia.

On the other hand, to the inner ring 6, a disc portion 11 which is orthogonal to the axis and protrudes outward is fixed by a bolt 12, and the disc portion 11 is provided on both housings 5 of the outer ring 5.
It is installed so as to be housed in the groove 9 formed between a and 5b. Plates 18 for positioning the bearing member 7 are attached to both end surfaces of the inner ring 6 by bolts 19.

A buffer member 8 having a predetermined viscosity is filled in the gap between the outer ring 5 and the inner ring 6 arranged as described above, and the buffer member 8 has a circle in the groove 9 as shown in the drawing. It is also filled around the plate portion 12. The cushioning member 8 is injected into the inside from an injection port 13 formed on the outer peripheral surface of the housing 5b of the outer ring 5, and the injection port 13 has a plug 14
Is screwed on and closed.

Therefore, the outer ring 5 and the inner ring 6 are in contact with each other via the cushioning member 8, and the disc portion 12 has a function of expanding the contact area. Here, it is possible to change and adjust the viscous damping coefficient of the damping vibration system by the damper member 3 by appropriately changing the shape and outer diameter of the disc portion 12. Although only one disk 12 is shown in FIG. 1, the thickness and the number of disks can be set as appropriate.

The cushioning member 8 is preferably a jelly-like one having a high viscosity and heat resistance, such as a silicone gel, but is not limited to this. For example, another semi-solid substance or a fluid substance. Any material, such as a liquid material, a powdery material, or a granular material, can be used as long as it is interposed between the outer ring 5 and the inner ring 6 and can impart a resistance force to the relative motion of each other.

The coupling member 4 is the damper member 3
Two inner conical surface portions 6a, 6b which are integrally formed inside the inner ring 6 and whose diameter decreases from both shaft ends toward the shaft center,
Outer conical surface portion 15 contacting each inner conical surface portion 6a, 6b
a and 16a are respectively formed, and the two wedge members 15 and 16 are arranged such that the end faces having a small diameter face each other. That is, the inner conical surface portions 6a and 6b are
It is a part of the inner ring 6 of the damper member 3 and also constitutes the coupling member 4. In this sense, the coupling member 4 is provided integrally with the damper member 3.

The wedge members 15 and 16 can be moved axially closer to each other by tightening a bolt 17. Therefore, bolt 1
The outer surfaces of the main shaft 1 and the ball screw shaft 2 of the motor M and the inner conical surface portions 6 a, 6 of the inner ring 6 can be simply tightened by tightening 7.
Both wedge members 15 and 16 are axially fitted between the two shafts 1 and b, and the contact surfaces of the wedge members 15 and 16 press each other, so that the two shafts 1 and 2 can easily maintain the concentricity and the inner ring 6 Are fixed and connected respectively.

Considering that the diameter of the main shaft 1 of the motor M is standardized, the damper with a coupling according to the present invention can be applied to various motors and has high versatility. The mating shaft connected to the main shaft 1 of the motor M is not limited to the ball screw shaft 2 described above, and various rotary shafts can be used and can be connected to the ball screw shaft via this.

Next, the operation of the present embodiment will be described. The damper with a coupling, which is an embodiment of the present invention, is applied to a servomotor used for rotational driving of an important NC axis that determines positioning accuracy in a high-speed and high-precision machining equipment such as an NC machine tool.

When this damper with a coupling is used, as shown in FIG. 1, the main shaft 1 of the motor M and the ball screw shaft 2 for transmitting the rotational driving force from the main shaft 1 of the motor M are arranged. The dampers with a coupling are set so that they are coaxially arranged in a straight line, and the shafts 1 and 2 are inserted inside, and the bolts 17 are tightened. Thereby, the connection between the two shafts 1 and 2,
It is possible to install the damper with coupling in one piece at a time.

Thus, the main shaft 1 is attached to the ball screw shaft 2.
In the case of operating the servo motor connected to the motor M, if the gain in the servo circuit is increased in order to improve the followability of the motor M, the motor M becomes sensitive and vibrates by itself as described above. However, in the present embodiment, when the motor M tries to vibrate, the outer ring 5 having a predetermined inertia tries to rotate at a constant speed and the damper member 3 is sealed in the gap between the outer ring 5 and the inner ring 6 in the present embodiment. The buffer member 8 tries to suppress the vibration of the inner ring 6 directly connected to the main shaft 1 of the motor M. That is, the buffer member 8 acts to absorb the speed difference between the inner ring 6 that is about to vibrate and the outer ring 5 that is about to rotate at a constant speed.

As described above, according to the present embodiment, the induced vibration can be efficiently damped, so that the gain of the motor can be dramatically increased and the tracking accuracy of the servo motor can be greatly increased. Can be improved.
For example, in an experiment applied to a general NC machine tool, it was possible to obtain an extremely high following accuracy in positioning accuracy of a work tip, which is about half or less as compared with that without a damper member.

Moreover, since the main shaft 1 and the ball screw shaft 2 of the motor M can be connected and the damper with the coupling can be attached at once by one component, the total axial length before attaching the damper member can be increased. It is possible to easily and quickly attach various motors of various equipments without requiring special modification such as lengthening the main shaft or extending to the half output side.

Further, since the positional relationship between the damper member 3 and the motor M is made constant, there is an advantage that the damping effect is stable and a desired follow-up accuracy can be surely obtained.

The embodiment described above is not intended to limit the present invention, and various modifications can be made. In the above-described embodiment, the description has been given of the application to the servo motor used in the NC machine tool, but the present invention is not limited to this and may be applied to, for example, a stepping motor, which requires high-speed and high-accuracy positioning. It is preferable to apply it to the connecting part of the rotating shaft. Further, the invention is not limited to the connection part with the main shaft of the motor, but can be applied to a general connection part of two shafts.

[Brief description of drawings]

FIG. 1 is a half cross-sectional view showing a state in which a damper with a coupling according to an embodiment of the present invention is attached to a connecting portion of a main shaft of a motor.

FIG. 2 is a cross-sectional view showing a state in which a main shaft of a motor is extended to a side opposite to an output side and a damper is attached to an end of the main shaft.

FIG. 3 is a cross-sectional view showing a state in which a damper is directly attached to a main shaft of a motor.

FIG. 4 is a cross-sectional view showing a state in which a mating shaft connected to the main shaft of the motor is extended and attached by the amount of the damper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main shaft (shaft), 2 ... Ball screw shaft (shaft), 3 ... Damper member, 4 ... Coupling member, 5 ... Outer ring, 6 ... Inner ring, 6a, 6b ... Inner conical surface part, 7 ... Bearing member, 8 ... Buffer member, 9 ... Groove portion, 11 ... Disc portion, 15, 16 ... Wedge member, 15a, 16b ... Outer conical surface portion, M ... Motor.

Claims (6)

[Claims] 1. A damper with a coupling, wherein a coupling member for connecting two shafts is integrally provided inside the damper member for damping the vibration of the vibration system. 2. An outer ring having a predetermined mass is rotatably provided on a substantially cylindrical inner ring via a bearing member, and
A cushioning member is interposed in the gap between the inner ring and the outer ring to dampen vibrations transmitted to the inner ring, and two shafts that are integrally provided inside the damper member and are arranged in series. And a coupling member that connects the two shafts by fixing them to the inner ring of the damper. 3. The damper with a coupling according to claim 2, wherein one of the two shafts is a main shaft of a motor as a rotation driving means. 4. The cup according to claim 2, wherein the inner ring is provided with a disc portion that is orthogonal to the axis and projects outward, and the disc portion is housed in a groove formed inside the outer ring. Damper with ring. 5. The damper with a coupling according to claim 2, wherein the buffer member is a silicon gel. 6. The coupling member includes two inner conical surface portions that are integrally formed on the inner side of the inner ring and have a diameter that decreases from both shaft ends toward the center of the shaft, and outer coupling members that contact the inner conical surface portions. And a wedge member having a conical surface portion and end faces having a small diameter that are arranged to face each other, and by moving the wedge members toward each other in the axial direction, the two shafts are The damper with a coupling according to claim 2, which is fixed to each of the inner rings.