JPH0661339U - Rolling machine - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a rolling machine for producing excellent rolled products with high precision, with both tables on which cutting tools are attached in perfect synchronization. [Structure] A holder 11 is provided on a pair of tables 7 that slide on a pair of guide bars 6, and a pair of flat blades 12 attached to the holder 11 move in opposite directions to move the work 1
In a rolling machine for rolling 4; a meshing mechanism 1 including a rack 1a fixed to a table 7 and a pinion 1b;
The pair of ball screws 9 are provided with a moving mechanism 2 in which bolts 9a are axially attached to the frame 5 and nuts 9b are attached to the table 7, and are fixed to the frame 5.
A pair of servo motors 3 for rotating and driving the motor, and an NC device 4 for detecting the position and speed and feeding back the position and speed for position control and speed control are provided.
7 is synchronized with the feed rate A and the mutual positional relationship B between the table and the center of the center pin.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a vertical type or a horizontal type, in which two flat blade tools press and move in opposite directions across the workpiece to roll the workpiece, and the blade shape of the blade tool is imprinted on the outer circumference. Related to the rolling machine. It is used as a device for forming splines and male threads on a workpiece.

[0002]

[Prior art]

 In a rolling machine that moves the blades attached to the pair of tables sliding on the guide bar so as to face each other via the holders, rolls the workpiece inserted between them, and shows the shape of the blades. The two tables to which a pair of cutting tools are attached must be synchronized with respect to the feed rate and the mutual positional relationship with the axis of the center pin.

Conventionally, this synchronization method has the following configuration. First, as described in Japanese Utility Model Publication No. 3-18023 and Japanese Patent Application Laid-Open No. 2-187227, a pair of ball screws are rotated by two servo motors that are synchronously driven and controlled in opposite directions at a constant speed. The pair of blades fixed to these nuts are moved at a constant speed along the ball screw (prior art 1). In addition, as disclosed in Japanese Patent Laid-Open No. 63-235036, a method of adopting an electric servomotor with rotational speed feedback control and performing synchronous control of the table position by a linkage structure of a rack and a pinion. There is (Prior art 2).

[0004]

[Problems to be solved by the device]

 However, all the conventional structures have drawbacks. In prior art 1, the nut of the ball screw plays a role of thrust for moving the table by the drive of the servo motor, but the reaction force related to this thrust causes the ball screw to expand and contract via the nut, and The feed rate and the mutual positional relationship between the table and the axis of the center pin were misaligned.

On the other hand, the prior art 2 also does not perform the position feedback control but only the rotational speed feedback control, and depends on the synchronous operation adjusting function between the rack and the pinion, so that the processing accuracy is limited. The mutual positional relationship between the two tables to which the cutting tool was attached was not controlled, and even if the position of the cutting tool was misaligned, it could not be corrected. Especially, since the synchronization depends only on the pinion and the rack, the backlash increases with the passage of time, and the thrusts of the two cutting tools are unbalanced, which has an adverse effect.

The present invention overcomes the above-described problems, and is provided with a meshing mechanism including a rack and a pinion, a table moving mechanism using a ball screw, and an NC device, and both of which are equipped with a cutting tool. It is an object of the present invention to provide a rolling machine for producing excellent rolled products with high accuracy by keeping the table in perfect synchronization with respect to the mutual positional relationship between the feed rate and the center of the center pin.

[0007]

[Means for Solving the Problems]

 In the rolling machine of the present invention, a holder is provided on a pair of tables that slide on a pair of guide bars provided on a frame, and a pair of flat-shaped cutting tools attached to the holder move in opposite directions so that the double-edged blades move. In a rolling machine for rolling a work inserted between tools to imprint the blade shape of the cutting tool, the rack (1a) fixed to a pair of the above tables is engaged with the rack to rotate the work. A meshing mechanism (1) consisting of a pinion (1b) supported on the base of a center pin that is movably held, and a pair of ball screw bolts parallel to the guide bar are rotatably attached to the frame. And a table moving mechanism (2) in which a nut of the ball screw is attached to each table via a supporter, and the ball screw is fixed to the frame and each ball screw is connected via a transmission mechanism. A pair driven to rotate The servo motor (3) and the encoder attached to the servo motor detect the position and speed, and feed them back to arrange the NC device (4) for position control and speed control. It is characterized in that both tables at the time are configured to synchronize the feed rate (A) with the mutual positional relationship (B) between the center of the center pin and the axis.

[0008]

[Action]

 When the start position and the target position to stop after pressing and rolling the work surface are set, and the table feed speed is input to the NC unit, the servo motor is momentarily driven through the servo control unit based on this command. Operate. Then, the distance moved and the speed are respectively fed back and controlled so that the difference from the commanded value becomes 0, so that the processing accuracy is kept high. Also, when the reaction force related to the thrust that moves the table acts on the nut, and the ball screw tries to elastically deform and expand and contract, the meshing mechanism of the rack and pinion fixed to the table acts as an elastic deformation compensator. It weakens the reaction force applied to the nut and suppresses it. On the other hand, if the backlash or the like that occurs between the rack and the pinion is about to increase, the ball screw that is the moving mechanism that fixes the nut to the table prevents this. Thus, not only the meshing mechanism and the moving mechanism complement each other, but also when the position is accurately detected in addition to the speed to perform the feedback control, the two tables become completely synchronized. Therefore, the characteristics of the machine do not change due to the movement of the machine or the passage of time, and stable rolling with high precision is achieved.

[0009]

【Example】

 Hereinafter, the present invention will be described in detail based on embodiments. (1) Configuration of Rolling Machine FIGS. 1 to 3 show an embodiment of the rolling machine according to the present invention. It is a modification of a rolling machine driven by a hydraulic cylinder. The frame 5 forming the frame, the pair of guide bars 6 and 6 horizontally and parallel to the frame 5, and the pair of tables 7 and 7 sliding on the respective guide bars 6 and 6 are modified. It uses the same rolling machine as it is.

Supporters 8, 8 are formed at one end of each table 7, 7, and a nut 9 a of a ball screw 9 is fixed to the supporter 8. The bolt 9b of the ball screw 9 is rotatably supported by bearings 10 and 10 provided on both sides of the frame 5 in parallel with the slide bar 6, and the ball screw 9 is rotated to rotate the ball screw 9 on the table 7. A moving mechanism 2 for moving the

Holders 11, 11 are provided so as to face each other on the front side of the pair of tables 7, 7 facing each other. Reference numerals 12 and 12 denote flat blades attached to the facing surfaces of the holders 11 and 11 (Fig. 2). These cutting tools 12 and 12 sandwich the work 14 rotatably held by the center pins 13 and 13 of the tailstock, and reciprocate in opposite directions to roll the work 14, thereby causing a desired spline (or , Male thread). As shown in FIG. 1, the cutting tools 12 and 12 are parallel to each other and are located at positions opposite to each other so as to be axially symmetric (point-symmetrical in the plan view of FIG. 1) with respect to an axis passing through the center pins 13 and 13. Will be distributed. Then, the table 7 is arranged with the reference parts 12a of the respective cutting tools 12, 12 equidistant from the axis. The pair of tables 7 and 7 are also arranged so as to be axially symmetric with respect to the axis passing through the center pins 13 and 13. This is because the load balance is good when the tables 7 and 7 move in the opposite direction and are rolled.

Reference numerals 1a and 1a denote racks fixed to the rear surfaces of the respective tables 7 and 7 (FIG. 2). The racks 1a, 1a are formed with blades on the opposing surfaces, and the pinion 1b is engaged with the racks 1a so as to be sandwiched between them. The pinion 1 b is supported by the base portion 17 of the center pin 13. As described above, the rack 1a and the pinion 1b form the meshing mechanism 1. When only the ball screw 9 is used, the reaction force related to the thrust for imprinting the blade shape of the cutting tool 12 on the work 14 causes elastic deformation of the bolt 9b, but this is for reducing the deformation.

Reference numerals 18 and 18 denote toothed pulleys fixed to one ends of the bolts 9 b and 9 b of the ball screws 9 and 9 supported by the bearing 10. Brackets 19, 19 are provided on the side surface of the frame 5 on the toothed pulley 18 side, and a pair of servomotors 3, 3 are attached to the brackets 19, 19. The toothed pulley 20 is also fixed to the shaft of the servomotor 3, and a toothed belt 21 is hung between the toothed pulleys 18 and 20 to form a transmission mechanism. The rotation of the servomotor 3 is accurately transmitted to the ball screw 9 via such a transmission mechanism. In the present embodiment, a semi-closed loop system is adopted, and the position is detected by the rotation angle of the axis of the servo motor 3. If there is a precision error or the like of the ball screw 9, the actual movement amount of the table 7 is not proportional to the rotation angle of the ball screw 9. Therefore, the meshing mechanism 1 serves to increase the static rigidity of the ball screw 9. Further, when an error amount due to backlash between the pinion and the rack by the meshing mechanism 1 and an elliptical deformation of the pinion 1b is about to increase, the moving mechanism 2 suppresses this. The servomotor 3 has a sufficient torque to give a thrust force higher than that required for the cutting tool 12 to roll-form the work 14.

As the servo motor 3, an AC servo motor is used, and an encoder 25 having the functions of the position detector 22 and the speed detector 23 is attached to the rear part of the AC servo motor. One is to detect the rotation angle of the axis of the servo motor 3 and the other is to detect the rotation speed. The feed speed and the position of the tables 7 and 7 which change every moment are accurately detected by the position detector 22 and the speed detector 23, and the detected electric signals are sent to the NC device 4 connected to each servo motor. provide feedback. This is to catch the variation in the feed rate between the pair of tables 7 and 7 and the positional deviation between the tables 7. Then, the electric signal compared in the NC device 4 controls the servomotor 3 so that the pair of tables 7 and 7 feed the feed speed A and the table 7 and the center of the center pin 13 to each other. The positional relationship B is synchronized. FIG. 3 shows that the two tables 7 and 7 have a feed rate A and a mutual positional relationship B between the table 7 (specifically, the position of the reference portion 12a) and the axis of the center pin 13, It is a figure showing how the NC control system is synchronized.

(2) Operation and Action of Rolling Machine Next, the operation and action of the rolling machine will be described. First, the starting position of the cutting tool 12 and the target position at which the work 14 is rolled and then stopped are input to the NC device 4. Here, the moving distances of the pair of cutting tools 12, 12 are set to be equal. Next, the feed rates of the tables 7 moving in the opposite directions are input.

After that, the work 14 is rotatably held by the center pins 13 and 13, and the start switch of the NC device 4 is turned on. Then, the two servo motors 3, 3 are started, and the pair of tables 7, 7 move along the guide bars 6, 6 in mutually opposite directions while synchronizing their positional relationship and speed. In this way, the cutting tools 12, 12 reach the outer peripheral portion of the work 14. When the cutting tools 12, 12 reach the work 14, the cutting tool 12 moves the work 14 in the reciprocal directions while imprinting the forming surface of the work 14 on the surface of the work 14, thereby rolling the work 14 around the axis, and thus the work 14 is pressed. A spline (or male thread) is formed by rolling on the surface.

In this rolling process, the position where the pair of cutting tools 12, 12 comes into contact with the work 14 is at a position opposite to the work 14. The movement of the cutting tool 12 causes the work 14 to roll around the axis, and the shape formed by one of the cutting tools 12 of the work 14 is sent to the forming processing surface of the other cutting tool 12, so that the work 14 is formed. If the parts and the blade shape of the cutting tool 12 do not match, a highly accurate rolled product cannot be obtained.

By the way, at the time of rolling forming, the reaction force of the thrust for moving the table 7 tends to expand and contract the bolt 9b of the ball screw 9 via the nut 9a. However, since the meshing mechanism 1 including the rack 1a fixed to the table 7 and the pinion 1b is separately adjusted in synchronization, the expansion and contraction is prevented. On the other hand, if an error such as a backlash derived from the configuration of the pinion 1b and the rack 1a is attempted to be large, the fitting state of the bolt 9b and the nut 9a of the moving mechanism 2 of the ball screw 9 will brake and prevent this. To do. Thus, in the NC control system, not only the speed and position are accurately detected by the encoder 25 and feedback control is performed, but the meshing mechanism 1 and the moving mechanism 2 complement each other from a mechanical aspect. Both tables 7 and 7 are now in perfect synchronization with respect to position and feed rate. Therefore, the blade shape of the work 14 formed by one of the cutting tools 12 perfectly matches the cutting shape of the other cutting tool 12 when the work 14 rolls.

After that, when the pair of cutting tools 12, 12 pass through the work 14 and reach the target position, the servo motor 3 stops and the table 7 also stops. Finally, the work 14 is removed from the center pin 13. Then, by driving the servo motor 3 in the reverse direction, the table 7 returns to the starting position. The above series of operations is automated.

(4) Effects of the Embodiment According to the rolling machine having the above-described aspect, since the encoder 25 detects the position and speed to perform the feedback control, only the rotation speed feedback control is performed conventionally. Compared to the above, the tables 7 and 7 were able to synchronize each other with high accuracy. Further, mechanically, the nut 9a of the moving mechanism 2 and the rack 1a of the meshing mechanism 1 are both fixed to the table 7. Therefore, when one mechanism tries to increase the error, another mechanism works to suppress it. As a result, the two tables 7 and 7 were corrected for imbalance in terms of both position and speed. As a result, the accuracy was more uniform, the symmetry was better, and the repeatability was also higher than the structure for synchronous transmission using the ball screw 9 alone and the structure for performing synchronous control only by the cooperation of the rack 1a and the pinion 1b. . And, since the processed products are uniform, assembly using such rolled products became easy. Furthermore, by remodeling the rolling machine driven by a hydraulic cylinder, not only can the old equipment be restored and restored, but an oil tank is no longer required, and work can be improved. It was also possible to easily deal with design changes and improve the functionality.

It should be noted that the present invention is not limited to the one shown in the above embodiment, and various modifications can be made within the scope of the present invention depending on the purpose and application. For example, the transmission mechanism between the servo motor 3 and the ball screw 9 is not limited to the embodiment, and may be a direct connection by a coupling. Further, as the servo motor, a DC servo motor can be used instead of the AC servo motor.

[0022]

[Effect of device]

 As described above, in the rolling machine of the present invention, the pair of tables to which the cutting tools are attached are completely controlled in terms of the positional relationship between the feed rate and the center pin axis from both sides of the control system and the mechanical system. Since it is configured to be synchronized, it exerts an excellent effect in improving the precision of rolled products.

[Brief description of drawings]

FIG. 1 is a front view of a rolling machine used in Examples.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a block diagram showing a control system for synchronizing a pair of tables in the rolling machine according to the embodiment.

[Explanation of symbols]

 1 meshing mechanism 1a rack 1b pinion 2 moving mechanism 3 servo motor 4 NC device 5 frame 6 guide bar 7 table 8 supporter 9 ball screw 9a nut 9b bolt 11 holder 12 cutting tool 13 center pin 14 work 15 rack 16 pinion 17 base

Claims (1)

[Scope of utility model registration request] 1. A holder is provided on a pair of tables that slide on a pair of guide bars provided on a frame, and a pair of flat-shaped blades attached to the holders move in opposite directions, and between the blades. In a rolling machine for rolling the inserted work to imprint the blade shape of the cutting tool, a rack (1a) fixed to a pair of the above tables, and a center that meshes with the rack and rotatably holds the work. A meshing mechanism (1) consisting of a pinion (1b) supported on the base of a pin, and a pair of ball screw bolts parallel to the guide bar are rotatably attached to a frame, and the nut of the ball screw is attached. And a table moving mechanism (2) which is attached to each table via a supporter, and is fixed to the frame, and a pair of servo motors for rotationally driving the ball screws through a transmission mechanism. (3) and an encoder attached to the servo motor, which detects the position and speed, and feeds back the detected position and speed to provide an NC device (4) for position control and speed control. Both tables have a mutual positional relationship (B) between the feed rate (A) and the center of the center pin.
A rolling machine characterized by being configured so as to synchronize with each other.