WO2009006756A1

WO2009006756A1 - A numerical control indexing equipment with an improved worm transmission device

Info

Publication number: WO2009006756A1
Application number: PCT/CN2007/002106
Authority: WO
Inventors: Zhengnan Wu
Original assignee: Zhengnan Wu
Priority date: 2007-07-09
Filing date: 2007-07-09
Publication date: 2009-01-15

Abstract

A numerical control indexing equipment with an improved worm transmission device includes a basal body (1), a main shaft (4) rotatably supported on the basal body, a worm gear (5) mounting on the main shaft, and a servo motor (7) installing in the basal body. It is characterized in further including a worm shaft (601) rotatably supported on the basal body and connected with the servo motor, and worm sleeves (602) fit on said worm shaft. Said worm sleeves have two section of helical teeth symmetrically arranged in the axial direction, and said two section of helical teeth can be adjustably engaged with the outside surface of the teeth of saidworm gear from two axial sides. Because there are two section of helical teeth formed on the worm sleeves, we can adjust one of them to close or go apart from the outside surface of the teeth of said worm gear, thus can optically adjust the backlash in a simple manner and make each tooth achieve the best engagement. This equipment can easily adjust the backlash and has simple structure, good transmission accuracy, effective practicability, and lower manufacture cost.

Description

Numerical control indexing device with improved worm drive pair Technical Field '

The invention relates to a numerical control indexing device with an improved worm drive pair, which can easily adjust the backlash of the worm gear pair to an optimal state to obtain an optimal transmission effect. Background technique'

The conventional numerical control indexing device includes a base body, an indexing plate body, a main shaft, a worm gear pair, a spindle locking mechanism, a servo motor, and a controller. The main shaft and the worm are rotatably supported on the base body and the rotating shafts thereof are perpendicular to each other. The indexing disc body is connected to the main shaft for clamping the workpiece to be processed, the worm wheel is fixedly mounted on the main shaft and meshed with the worm, and the worm is coupled to the servo motor. Output shaft. The spindle locking mechanism includes a locking cylinder and a brake pad connected to the spindle. The piston of the locking cylinder is in contact with the brake pad in the first position to limit the rotation of the spindle, and the second position is disengaged from the brake pad to allow the spindle to freely rotate. When the numerical control indexing device works, the controller controls the servo motor to operate, drives the worm gear and worm wheel group to drive the spindle to rotate, and rotates the indexing disk to the required angle. Then the spindle locking mechanism acts to lock the spindle, and then the workpiece can be machining.

In order for the CNC indexing device to work properly and achieve high accuracy, the flank backlash (tooth backlash) of the worm gear pair must be controlled to an ideal state. Because the backlash of the tooth surface is too large, it will generate a hollow motion, which will reduce the accuracy, which will cause the squeaking sound when rotating and adversely affect the processing effect; and the backlash of the tooth surface is too small or there is no backlash, which will cause poor lubrication, resulting in poor lubrication. The heat is stuck and the drive fails.

At present, a worm gear pair capable of adjusting the backlash of the tooth surface (backlash of the tooth surface) has been proposed, for example, by using a double worm or a similar compensation mechanism to achieve the purpose of eliminating backlash, which is complicated in structure and difficult to adjust. Also disclosed, there is a special design and improvement of the worm gear profile. The complex pitch worm gear pair has a worm thread gradually increasing in thickness from one end to the other. Therefore, when the worm moves in the axial direction while meshing with the worm wheel, the backlash between the two can be adjusted to a desired degree. The worm gear has two leads, one threaded surface of the worm thread has one lead and the other threaded surface has a slightly different lead. Its characteristics are that the number of meshing teeth is large, the transmission effect is accurate, and the backlash adjustment is easy. The disadvantages are complicated structure, difficult processing and high cost.

In addition, the Chinese utility model patent "CNC indexing device with combined worm" issued by the applicant and approved by the applicant is CN2897537, which is integrally coupled and rotatably supported on the substrate. The two worms are arranged, and the helical teeth of the two worms are placed on both sides of the axial section of the worm gear perpendicular to the worm axis. The two worms of the combined worm mesh with the worm gear from both sides, and can be adjusted to make the helical teeth close to or away from the worm wheel. The outer flank of the tooth, whereby the backlash can be easily adjusted to an optimum state for optimal engagement of each tooth. However, due to the combination of the two worms, the two worms need to be loosened at the same time to adjust the backlash, and then adjusted and assembled again. The adjustment and installation are still quite difficult and take a long time. 'And the two worms need to be manufactured separately and must be guaranteed to have a considerable degree of precision, which is costly to manufacture. SUMMARY _t

SUMMARY OF THE INVENTION An object of the present invention is to provide a numerically controlled indexing device having an improved worm drive pair and capable of easily adjusting the backlash of a worm worm gear pair to an optimum state in view of the deficiencies of the prior art.

To achieve the above object, the present invention provides a numerically controlled indexing device having an improved worm drive pair, comprising: a base body, a main shaft rotatably supported on the base body, a worm wheel mounted on the main shaft, and mounted on the A servo motor on a base body, further comprising: a worm shaft rotatably supported on the base body and drivingly coupled to the servo motor, and a worm that is axially movably fitted on the worm shaft The worm has two axially symmetric helical teeth and the two segments The helical teeth are adjustably engaged with the outer tooth faces of the worm gear teeth from both sides of the axial direction.

Preferably, both ends of the worm are detachably coupled to the worm shaft by a tightening ring and a coupling. '

Preferably, the end of the worm shaft is connected with a first transmission gear, and the output shaft of the servo motor is connected with a second transmission gear, and the first transmission gear meshes with the second transmission gear.

Compared with the prior art, the present invention is applied to a worm to form two axially symmetrical helical teeth, and after installation, the two helical teeth engage the worm gear from both sides. When the backlash needs to be adjusted, the worm can be adjusted unilaterally so that the helical teeth are close to or away from the outer flank of the worm gear teeth, so that the backlash can be more easily adjusted to the optimum state for optimal engagement of each tooth. The numerical control indexing device with combined worm provided by the invention has the advantages of simple structure, easy backlash adjustment, high transmission precision and strong practicability, and the two-stage helical teeth of the worm are integrally formed, and the manufacturing cost thereof is low. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front elevational view of a numerically controlled indexing device having a combined worm showing its external configuration. Figure 2 is a plan view of Figure 1.

Figure 3 is a left side view of Figure 1.

Figure 4 is a cross-sectional view of Figure 3 showing the internal structure thereof.

Fig. 5 is a cross-sectional view of Fig. 1 showing the internal structure from the other direction. detailed description

Referring to Figures 1 to 3, a numerically controlled indexing device having a combined lever has a base body 1 in the form of a box having a rotatable indexing plate 2 and an indicator 3 in front of the base 1. The front surface of the indexing disk 2 has a T-shaped groove 201 for clamping a workpiece. The outer circumference of the indexing disc 2 has an angular value scale, which is indicated with The device 3 cooperates to indicate the rotation angle of the indexing disk 2. An inlet port 101 for adding lubricating oil is disposed on a top surface of the base body 1, and an observation window 102 for indicating a lubricating oil surface inside the base body is provided on both sides of the base body 1, for use with a controller, a liquid/pneumatic driving device, and the like. Connected interface (not shown). On one side of the base body 1, there is an opening covered by a side cover 103, through which the worm adjustment can be performed.

Referring to Fig. 4 and Fig. 5, the main body 1 is provided with a main shaft, a worm wheel, a worm mechanism, a servo motor, a transmission gear, a spindle locking mechanism, and an origin return mechanism. The details are as follows:

The main shaft 4 is rotatably supported by the bearing housing 402 via a bearing 401. The front end of the main shaft 4 is connected with an indexing plate holder 202, and the indexing plate body 2 is fixed to the indexing plate holder 202 to rotate with the spindle 4.

The spindle locking mechanism includes a lock cylinder mounted at a rear portion of the base body 1 near the main shaft 4, and a brake pad 801 fixed to a rear end of the main shaft 4. The lock cylinder includes a cylinder block 802, a cylinder head 803, a piston 804, a return spring 805, and the like. When the spindle 4 drives the indexing disk 2 to rotate into position, the piston 804 of the locking cylinder is actuated by the controller, the electromagnetic valve 806, etc., and the brake pad 801 is pressed to lock the spindle to prevent the swing from being generated when the workpiece is processed. When the spindle 4 needs to be rotated, the piston 804 of the lock cylinder can be disengaged from the brake pad 801 by the controller, the solenoid valve 806, the return spring 805, and the like.

The worm gear 5 is fixedly mounted in the middle of the spindle 4 to drive the spindle 4 to rotate.

The worm mechanism includes a worm shaft 601 and a worm 602. The worm shaft 601 and the worm 602 are coaxially fitted together and the two ends thereof are detachably coupled integrally by the pressing rings 603, 604 and the coupling 605. The worm shaft 601 and the worm 602 are combined and rotatably supported on the bearing housing 608 by bearings 606, 607. A transmission gear 609 is coupled to an end of the worm shaft 601. The worm 602 has two axially symmetrical helical teeth. After installation, the two helical teeth of the worm 602 are placed on both sides of the axial section a-a of the worm wheel 5 perpendicular to the worm axis, and the teeth of the worm gear 5 are meshed on both sides. The outer tooth surface rotates to drive the worm wheel 5. When the backlash needs to be adjusted, the side cover 103, servo motor 7 and associated fasteners can be removed, single side adjustment The entire worm 602 has its helical teeth near or away from the outer flank of the worm 5 teeth, thereby adjusting the backlash to an optimum condition and optimally engaging each tooth.

The servo motor 7 is fixedly mounted on the motor support plate 701. The output shaft of the servo motor 7 is connected with a transmission gear 702. The transmission gear 702 meshes with the transmission gear 609 of the worm shaft 601, thereby driving the combined worm to rotate.

The home position returning mechanism includes an inductive ring 901 connected to the worm wheel 5 via the connecting base 904, and a micro switch 902 disposed adjacent to the inductive ring 901. The induction ring 901 has a stop 903. The microswitch 902 is electrically coupled to the controller. The working principle is as follows: When the controller receives the reset command, the servo motor 7 drives the combined worm and the worm wheel 5 to rotate, and the induction ring 901 rotates accordingly, until the micro switch 902 touches the block 903, the micro switch The 902 feeds a signal to the controller to decelerate the servo motor 7 and stop the indexing disk 2 in the correct position. At this time, the indicator 3 indicates the origin position of the scale value scale of the index body 2, which is generally the 0 degree angular scale position. Industrial applicability

The present invention is used in a worm to form two axially symmetrical helical teeth, and after installation, the two helical teeth engage the worm gear from both sides. When the backlash needs to be adjusted, the worm can be adjusted unilaterally so that the helical teeth are close to or away from the outer flank of the worm gear teeth, so that the backlash can be more easily adjusted to the optimum state, so that each tooth is optimally engaged. The device provided by the invention has the advantages of simple structure, easy backlash adjustment, high transmission precision, low manufacturing cost and good industrial applicability. The present invention has been described in detail by way of examples, but these descriptions are not to be construed as limiting the scope of the invention.

Claims

Patent claim

1. A numerically controlled indexing device having an improved worm drive pair, comprising: a base body, a spindle rotatably supporting the base body, a worm wheel mounted on the spindle, and a servo motor mounted on the base body, The method further includes: a worm shaft rotatably supported on the base body and drivingly coupled to the servo motor, and a worm that is axially movably fitted on the worm shaft, the worm having an axial direction The two-stage helical teeth are symmetrical, and the two-stage helical teeth are adjustably engaged with the outer tooth faces of the worm gear teeth from the axial sides. -

2. The numerically controlled indexing device with an improved worm drive pair according to claim 1, wherein the two ends of the worm are detachably coupled to the worm shaft by a pressing ring and a coupling.

The numerical control indexing device with the improved worm drive pair according to claim 1 or 2, wherein: the end of the worm shaft is connected with a first transmission gear, and the output shaft of the servo motor is connected a second transmission gear, the first transmission gear meshing with the second transmission gear.

4. The numerical control indexing device with an improved worm drive pair according to claim 1, further comprising: an origin return mechanism, wherein said origin return mechanism includes an induction ring coupled to said worm wheel and rotating therewith And a microswitch that accepts the induction loop control to feed a signal to the controller.