JPH0722862B2 - Machine tool spindle moving device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a spindle moving device for machine tools, and more specifically,
The present invention relates to a device for moving a main shaft in an axial direction by a rotating force of a rotation driving means.

[Conventional technology]

Conventionally, for example, in a horizontal boring machine or a machining center, it is known that the main shaft is moved in the axial direction to process a workpiece over a predetermined length or set the position of a tool. In order to move the spindle in the axial direction, a spindle moving device for a machine tool as disclosed in Japanese Patent Publication No. 1-12619 is required.

FIG. 3 is a diagram showing the same contents as the spindle moving device for a machine tool disclosed in Japanese Examined Patent Publication No. 1-12619.

In the figure, reference numeral 101 denotes a rotation driving means including a servo motor, and a drive gear 102 is coaxially fixed to a shaft 101A of the servo motor 101.

A passive 103 meshes with the drive gear 102, and a feed screw 103 is coaxially fixed to the passive gear 103.

A conversion device including a nut 105 is screwed onto the feed screw 104, and the nut 105 is moved in the axial direction by rotation of the feed screw 104. The nut 105 is integrally provided with a cylindrical quill 106, and the bearing 10 is provided inside the quill 106.
A main shaft 109 is pivotally supported via 7,108.

Then, when the servomotor 101 is rotated, its rotational force is transmitted to the feed screw 104 in the order of the drive gear 102 and the passive gear 103, and when the feed screw 104 rotates, the nut 105 moves. As the nut 105 moves, the quill integrated with the nut 105
106 and the main shaft 109 linearly move in the axial direction.

[Problems to be Solved by the Invention]

However, in the conventional spindle moving device for a machine tool, since the spindle 109 is supported by the nut 105 like a cantilever in terms of material mechanics, the supporting rigidity of the spindle 109 is weak, and Due to the backlash between the gear of the drive gear 102 and the gear of the passive gear 103, the movement distance accuracy of the nut 105 is not sufficient with respect to the rotation of the servo motor 1, and as a result, the movement distance accuracy of the main shaft 109 is sufficient. Could not be secured.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to improve the support rigidity of the main shaft and also to eliminate the backlash between the drive gear and the passive gear. Is to provide a spindle moving device.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a rotary drive means, a drive gear that is rotated by the rotary drive force of the rotary drive means, an intermediate gear that is rotated by the rotational force of the drive gear, and an intermediate gear. A pair of passive gears that mesh with each other around the intermediate gear, and a pair of feed screws that are connected to these passive gears and rotate, respectively, and the rotation of these feed screws causes axial movement of the feed screws. A pair of conversion devices to be moved, and a main shaft connected to these conversion devices and movable in the axial direction are provided, and further, the intermediate gear has the pair of passive gears with a straight line connecting the centers thereof being an intermediate point. The gears are arranged so as to be deviated from the center of the gears by a predetermined distance, and the positions of the intermediate gears and the positions of the pair of passive gears can be brought into relatively close engagement with each other.

[Work]

According to the present invention, by making the position of the intermediate gear and the position of the pair of passive gears relatively close to each other, the gear of the intermediate gear and the gear of the pair of passive gears are in a relationship of meshing by pressing their tooth surfaces against each other. Backlash in the meshing of is preferably removed.

Further, since the main shaft is connected and moved by the pair of conversion devices, an unreasonable force in terms of material mechanics does not act on the conversion device, and a highly rigid movement system for moving the main shaft is obtained.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a spindle moving device for a machine tool according to an embodiment of the present invention.

In the figure, reference numeral 1 is a rotation driving means composed of a servo motor, and the servo motor 1 is attached to a main spindle unit body 3. On the rotary shaft 1AR of the servomotor 1, a drive gear composed of a motor gear 4 is fixed coaxially.

A quill shaft 5 is rotatably provided in the main spindle unit main body 3 by a bearing (not shown), and a main shaft 6 is provided in the quill shaft 5 so as to be movable and fixed in the axial direction.

A ring member 7 and a tightening nut 8 are provided on the outer periphery of the end of the quill shaft 5.
Is provided. A cylindrical block 9 is fixedly mounted on the support ring 2 mounted on the end 3A of the main spindle unit body 3, and a large number of mounting holes 9 are circumferentially formed in the cylindrical block 9, and these mounting holes 9A are mounted in these mounting holes 9A. Inner ring 10 mounting hole 10A
The inner peripheral ring 10 is fixed to the cylindrical block 9 so as to be substantially concentric with the center of the main shaft 6 by screwing a bolt 11 into the mounting hole 9A in the state of being aligned. The diameter of the mounting hole 10A is larger than the diameter of the bolt 11, and the bolt 11
There is an adjustment gap between the mounting hole 10A and the bolt 11 in a state of being penetrated.

A bearing 12 is fitted and provided on the outer peripheral surface of the inner peripheral ring 10, and an intermediate gear composed of a large diameter gear 13 is fitted on the outer peripheral surface of the bearing 12, and the large diameter gear 13 is It is integrated with the circumferential ring 10. The large-diameter gear 13 meshes with the motor gear 4 via an idle gear 14. Idle gear
The center 14A of 14 is located off the straight line 1 connecting the center 13A of the large-diameter gear 13 and the center 4A of the motor gear 4, and the idle gear 14 is pressed against the large-diameter gear 13 and the motor gear 4 to bring it to that position. By fixing the idle gear 14, backlash between the idle gear 14, the motor gear 4 and the large diameter gear 13 is eliminated.

A pair of bearing cases 15 and 15 (only one is shown in FIG. 1) are fixed to the main spindle unit body 3, and a pair of bearing support cases are attached to the rear extension portion 18 of the main spindle unit body 3.
19, 19 (only one is shown in FIG. 1) are attached.

A pair of bearings 20 and 20 is mounted on each bearing case 15 and 15, and a pair of bearings 21 and 21 is mounted on each bearing support case 19 and 19, respectively, and a pair of feed screws 22 is attached to these bearings 20, 20; , 22 are supported respectively. Each lead screw 22,22 has a pair of passive gears 2
3,24 are fixed. The pair of passive gears 23, 24 are arranged at positions facing the large-diameter gear 13 with the large-diameter gear 13 as the center.

With respect to the large-diameter gear 13, the pair of passive gears 23, 24 has a straight line 25 connecting the centers 23A, 24A thereof to the center 13A of the large-diameter gear 13.
Are arranged so as to be biased by a predetermined distance from. That is,
The straight line 25 does not pass through the center 13A of the large diameter gear 13.

Further, as described above, the mounting hole 10A of the circumferential ring 10 and the bolt 1
Although there is an adjustment gap between 1, the mounting hole 10A of the inner ring 10 integrated with the large-diameter gear 13 is slightly decentered in the direction of arrow a in FIG. 2 from the designed normal assembly position. Puncture the position,
When the inner ring 10 is assembled to the cylindrical block 9, the center of the pitch circle of the large diameter gear 13 is slightly eccentric in the arrow B direction, and the large diameter gear 13 is pressed against the pair of passive gears 23, 24. The positions of the large-diameter gear 13 and the passive gears 23, 24 are brought close to each other, and the backlash in the meshing of these gears is removed.

Then, the above-mentioned feed screws 22 and 22 are provided with conversion devices 26 and 26, respectively.
(Only one is shown in FIG. 1). Each conversion device 26 is composed of a ball screw portion 26A integrated with the feed screw 22 and a ball nut 26B screwed to the ball screw portion 26A, so that the rotation of the feed screw 22 causes each conversion device 26, 26 to move in the axial direction. Has become.

Each conversion device 26, 26 is fixedly provided on one moving block 27, and this moving block 27 is connected to an end 6A of the main shaft 6 via a bearing 28.

Then, when the servomotor 1 is rotated, its rotational force is transmitted to the feed screws 22 and 22 in the order of the motor gear 4, the idle gear 14, the large-diameter gear 13, and the passive gears 23 and 24.
When 2,22 rotate, the conversion devices 26,26 move in the direction of the arrow in FIG. With the movement of the conversion devices 26, 26, the conversion device 26,
The main shaft 6 is moved inside the quill shaft 5 by receiving a force in the axial direction via a moving block 27 integrated with the 26.

According to the above configuration, the gear of the large-diameter gear 13 and the gear of the pair of passive gears 23, 24 by relatively bringing the position of the large-diameter gear 13 and the positions of the pair of passive gears 23, 24 into close proximity to each other, It is a relationship where they are pressed against each other. Therefore, the backlash between the large-diameter gear 13 and the pair of passive gears 23, 24 is removed,
The accuracy of the moving distance of the conversion device 26 can be improved with respect to the rotation speed of the servo motor 1, and as a result, the accuracy of the moving distance of the spindle 6 in the axial direction can be improved.

Further, since the end portion 6A of the main shaft 6 is supported by the pair of conversion devices 26, 26, unlike the conventional example, an unreasonable force in terms of material mechanics does not act on the conversion devices 26, 26, and It is possible to improve the support rigidity of the motion system in the axial movement.

In this embodiment, the conversion device 26 is a ball screw part.
It is composed of 26A and a ball nut 26B screwed to the 26A, but the conversion device is not limited to this and may be a mechanism composed of other screws and nut members.

Further, in the present embodiment, the servomotor 1, the motor gear 4, the idle gear 14, the large diameter gear 13, the passive gears 23 and 24,
A drive system such as the feed screws 22 and 22 is provided at the end 3A of the spindle unit 3, but this drive system can also be provided at the rear extension 18 of the spindle unit 3.

〔The invention's effect〕

As described above, according to the present invention, the position of one intermediate gear and the position of the pair of passive gears meshing with the intermediate gear are relatively close to each other, whereby the gear of the intermediate gear and the gear of the pair of passive gears are And are pressed against each other. Therefore, the backlash between the intermediate gear and the pair of passive gears is removed, and the accuracy of the moving distance of the conversion device can be improved. As a result, the accuracy of the moving distance in the axial direction of the main shaft can be improved.

Further, since the main shaft is supported and moved by the two conversion devices, unlike the conventional example, an unreasonable force in terms of material mechanics does not act on the conversion device, so that the supporting rigidity of the motion system in the axial movement of the main shaft is increased. There is an effect that can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a spindle moving device for a machine tool according to an embodiment of the present invention. FIG. 2 is a front view of a main part of the spindle moving device of the machine tool. FIG. 3 is a partial sectional view of a conventional spindle moving device for a machine tool. [Explanation of symbols for main parts] 1 …… Servo motor 4 …… Motor gear 6 …… Spindle 13 …… Large diameter gear 22 …… Feed screw 23,24 …… Passive gear 25 …… Straight line 26 …… Converter.

Claims (1)

[Claims] 1. A rotary drive means, a drive gear which is rotated by a rotary drive force of the rotary drive means, an intermediate gear which is rotated by the rotary force of the drive gear, and an intermediate gear which meshes with the intermediate gear and is centered around the intermediate gear. A pair of passive gears arranged at opposite positions, a pair of feed screws that are respectively connected to these passive gears and rotate, and a pair of conversion devices that are respectively moved in the axial direction by the rotation of these feed screws. , A main shaft coupled to these conversion devices and movable in the axial direction, and further, a straight line connecting the centers of the pair of passive gears to the intermediate gear deviates from the center of the intermediate gear by a predetermined distance. A spindle moving device for a machine tool, characterized in that the positions of the intermediate gear and the pair of passive gears are relatively close to each other and can be meshed with each other.