JPH09285879A - Friction welding method and friction welding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the rotational load caused by the rotation and pressure welding of joining members, to decrease iner-tial force and to raise the accuracy of joining angle by providing a stop reparing stage between, a heat generating stage and a stopping/joinining stage and controlling a relative angle at the time of stopping. SOLUTION: The rotational speed is decelerated from ω a to ω 1 during the time for t1 to t3. On the other hand, the feed speed is decelerated from va to v* during the time for t1 to t2 and, further, decelerated to v1 at the time t3. Meanwhile, a feed position is changed from Y1 to Y3. During the time for t3 to t4, rotation at the stop preparing rotational speed ω 1 and feed drive at the stop preparing feed speed v1 are continuously executed. During the time for t4 to t5, a servo motor for rotationally driving is decelerated and stopped and the rotation of the body of a main spindle is stopped. The stopping position of the servo motor for rotationally driving is controlled so that the joining angle between a joining member A and the joining member B becomes a desired set value at the time of stopping the body of the main spindle. After the servo motor for rotationally driving is stopped, upset is executed and the joining member A is feeding driven to a feed position D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction welding method and a friction welding apparatus for joining two joining members by using frictional heat by pressing the joining members while rotating them relative to each other.

[0002]

Friction welding is one of the techniques for joining joining members. Friction welding is suitable for butt welding of round bars and pipes and is widely used. Hereinafter, as an example of a conventional friction welding technique, a case where one joining member is fixed and the other joining member is driven will be described. in this case,
The joint member on the drive side is driven to rotate and is fed toward the joint member on the fixed side, and the joint surfaces of both joint members are abutted against each other.

FIG. 4 shows an example of the rotational drive and feed drive of the joining members in such friction welding. FIG. 10A is a time chart of the rotation speed ω of the joining member, in which the horizontal axis represents the time t and the vertical axis represents the rotation speed ω. FIG. 2B shows a state of feed driving of the joining member. The position Y of the joining member in the feed driving direction (hereinafter referred to as feed position Y) is taken on the horizontal axis and the feed speed v is taken on the vertical axis. Has been. In this frictional pressure welding, the pressure welding force of both joining members is controlled by increasing or decreasing the feed speed v. The feed position Y in FIG. 11B is shown in association with the time t in FIG. That is,
The time tx and the feed position Yx at the time tx are shown at the same position in the horizontal axis direction (the vertical line foot drawn from the time tx to the horizontal axis in FIG. 7B is the feed position Yx). .

As shown in FIG. 4, the joining member is rotated at the start of friction welding. Rotation speed is heat generation Rotation speed ωa
Then, keep constant and start the feed drive. After the feeding speed reaches the heat-generating feeding speed va, at time t0, both joining members come into contact with each other at the feeding position Ya. Friction heat is generated with the contact, and the temperature of the joint portion rises. The joint surface reaches a preset high temperature state by the time ta and the feed position Ya. In this high temperature state, the joint surface is softened to a predetermined level. The above is the heating step.

Next, the rotation of the joining member is suddenly stopped during the braking period from time ta to time tb. This sudden stop is generally forced by using an external brake. During the braking period, the joining member is fed and driven from the feeding position Ya to Yb. When the rotation is stopped, the feed rate is increased to the maximum feed rate vp, and the upset is performed to feed the joining member to the feed stop position D. The upset can increase the bonding force. The above is a stop joining process.

In the above, the joint surface is rapidly cooled with the start of deceleration of the rotation speed ω. If the temperature of the joining surface drops too much before the rotation is stopped, good joining cannot be achieved. Therefore, the braking period is set to a short time in consideration of the cooling rate of the joint surface.

In the friction welding described above, when the joining members are joined at a specific joining angle (the relative angle between the joining members in the joined state. The same applies hereinafter),
Generally, a mechanical lock mechanism is provided in a rotary drive machine that rotates a joining member. This lock mechanism is a mechanism for forcibly locking and stopping the rotation of the rotary drive machine when the joining member on the rotation side has a specific angle. By operating this lock mechanism at the time of sudden stop in the stop joining step, the joining members are joined at a specific joining angle.

[0008]

The structure provided with the lock mechanism as described above has the following problems.

(1) The lock mechanism can stop the rotary drive machine at only one position. In order to join various kinds of members, it is necessary to provide a lock mechanism for each joining angle. When the lock mechanism is used as described above, the versatility of the device is low.

(2) A large rotational load of the rotary drive acts on the lock mechanism. Therefore, it is necessary to make a device having a strong structure suitable for this rotational load, and the entire device is large.

(3) Since the rotary drive is forcibly locked, a large vibration is generated at the time of stop. Therefore, although it is possible to specify the joining angle with a certain degree of accuracy,
It is difficult to improve the accuracy of the joining angle.

In order to solve the above problems, it is desired to provide a friction welding technique capable of specifying the joining angle without providing a lock mechanism. In order to meet such a demand, it is possible to use a servo motor capable of phase control in a rotary drive machine. By controlling the stop position of the servo motor, it is possible to perform the joining at a desired joining angle. However, if the servo motor is simply applied to the conventional friction welding as shown in FIG. 4, the problems described below occur.

(1) The braking period (ta to tb) is set to a short time in consideration of the cooling speed of the joining member, and the servo motor must be stopped suddenly within the braking period. Since a very large inertial force acts at the time of sudden stop,
A large-capacity servo motor capable of stopping suddenly under this inertial force is required. Therefore, the device becomes large and the equipment cost also increases.

(2) Since the servo motor is suddenly stopped within the braking period, the controllable period is very short. It is very difficult to control the stop position of the servo motor so that the joining angle becomes the required value in this short period.

Here, it is conceivable to use the control of the servomotor and the external brake together in order to avoid the enlargement of the apparatus described in (1) above. However, in this case, vibration is generated in the device by using the external brake, and this vibration becomes a disturbance of the servo motor control. Therefore, it becomes more difficult to control the stop position of the servo motor.

"Object of the Invention" The present invention addresses the above-described problems and provides a friction welding method and apparatus which are capable of joining joining members at a desired joining angle and have the following advantages. (1) A lock mechanism is not required, and various types of members can be joined, and versatility is high. (2) Precision of angle determination of the joining angle is high. (3) Joining in the stop joining process. The inertial force of the member is reduced, and the device can be downsized.

[0017]

DISCLOSURE OF THE INVENTION The present invention is directed to a friction welding method in which the relative rotational speed, the relative angle, and the pressure contact force of the joining members are controlled, and the joining members are joined by abutting press contact while relatively rotating them. The relative rotation speed is set to a predetermined heat generation rotation speed, the pressure contact force is set to a predetermined heat generation pressure contact force, and a heat generation step of bringing the joint surfaces of the two joint members into a predetermined high temperature state, and the relative rotation speed are A stop preparation step of decelerating the high-temperature state lower than the heat generation rotation speed to a sustainable stop preparation rotation speed, and continuing relative rotation at the stop preparation rotation speed until the control disturbance of the relative angle during deceleration is resolved. And a stop joining step of stopping the relative rotation of the both joining members and controlling the relative angle at the time of stopping to join the both joining members at a desired relative angle.

In the above structure, the stop preparation step is provided between the heat generation step and the stop joining step. In the stop preparation process, the speed is temporarily reduced to the stop preparation rotation speed. At the stop preparation rotation speed, the high temperature state of the joint surface is maintained. Disturbances in the control of the relative angle occur due to disturbances such as vibrations when decelerating to the stop preparation rotation speed. Therefore, relative rotation at the stop preparation rotation speed is continued until this disturbance is resolved. In the stop joining process, deceleration stop is performed from the relative rotation state at the stop preparation rotation speed. At this time, the relative angle at the time of stop is controlled so that the two joining members are joined at a desired relative angle.

In the present invention, one joining member may be fixed so as not to rotate, and the other joining member may be rotated.
Further, both joining members may be rotated. In the latter case, the rotating directions of both joining members may be the same direction or opposite directions. Further, in the present invention, one of the joining members may be fixed in the pressure contact direction and the other joining member may be fed and driven to perform the pressure welding, or both joining members may be fed and driven to perform the pressure welding. . In the latter case, the feed driving directions of both joining members may be the same direction or opposite directions.

Further, in one aspect of the present invention, in the stop preparation step, the relative rotational speed is decelerated and the pressure contact force is made lower than the heat generation pressure contact force to reduce the high temperature state to a sustainable stop preparation pressure contact force. .

According to the above arrangement, in the stop preparation step, the pressure contact force of both joining members is reduced to the stop preparation pressure contact force. Here, the stop preparation rotation speed and the stop preparation pressure contact force are set so that the high temperature state of the joint surface in the heat generation step is maintained.

Further, the friction welding device of the present invention is configured to join both joining members by the friction joining method as described above, and a holding device for holding each joining member and a relative rotation of both joining members. And a feed drive device that relatively feeds and drives the joint members so as to make abutting press contact, a control that controls the rotation speed and phase of the rotation drive device, and the feed drive speed of the feed drive device. And a device.

According to the above construction, in the state where both the joining members are gripped by the gripping device, the relative rotation is performed by the rotation drive device, and the feed drive is performed by the feed drive device. The control device adjusts the relative rotation speed and the relative angle of the joining members by controlling the rotation speed and the phase of the rotation drive device. Further, the control device controls the feed drive speed of the feed drive device to adjust the pressure contact force of both the joining members.

[0024]

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

[Friction Welding Device] FIG. 1 shows an outline of the friction welding device of this embodiment. As shown in the figure, a spindle slide guide 3 is provided on the equipment base 1, and a spindle unit 5 is mounted in engagement with the spindle slide guide 3.

A spindle body 9 is rotatably supported by a spindle headstock 7 of the spindle unit 5, and a rotation axis of the spindle body 9 is set parallel to a sliding direction of the spindle unit 5. A chuck 11 that holds one of the joining members A is provided at the tip of the spindle body 9, and the chuck 11 clamps the side surface of the joining member A from a plurality of directions. A brake 12 for stopping the spindle body 9 is attached to the spindle stock 7. The brake 12 is provided for the purpose of security and safety, and does not operate when friction welding is normally performed.

Further, the headstock 7 is provided with a rotary drive servomotor 13, and the rotary drive servomotor 13 is provided.
Drive gear 17 on the connecting shaft 15 attached to the rotating shaft of
Has been fixed. The drive gear 17 is engaged with a driven gear 19 coaxially fixed to the main shaft body 9.

A feed drive servomotor 21 is attached to the equipment base 1, and a feed shaft 23 attached to the rotary shaft of the feed drive servomotor 21 is pivotally supported by the equipment base 1. . Feed shaft 2
3 is provided parallel to the sliding direction of the spindle unit 5. The feed shaft 23 is engaged with an engagement arm 25 projectingly provided on the bottom surface of the headstock 7. When the feed shaft 23 rotates, the main spindle unit 5 is guided by the main spindle slide guide 3 to be fed and driven. It has become.

Further, a table 27 is fixed on the equipment base 1, and a fixing clamp 29 for fixing the joining member B is provided on the table 27. The fixed clamp 29 fixes the joining member B so that the joining member B and the joining member A are located coaxially.

In addition, the rotary drive servomotor 13 and the feed drive servomotor 21 have encoders 3 respectively.
1, 33 are attached, and encoders 31, 33 are attached.
Detects the angular position of the rotary shaft of each servo motor and outputs it to a control device (not shown). Further, each servo motor is provided with a rotation speed sensor (rotation speed sensor) and a current sensor, and detects the rotation speed and the supply current value of each servo motor and outputs them to the control device.

FIG. 2 shows the configuration of a system for controlling the operations of the rotary drive servomotor 13 and the feed drive servomotor. This control system includes a host controller 35, a friction pressure welding controller 37, a friction rotation servo driver 39, and a pressure welding servo driver 41.

The host controller 35 monitors the operation of the entire system, and outputs a signal for instructing the friction welding controller 37 to start control, emergency stop of the motor, or the like. In addition, the controller 35 includes a friction welding controller 37.
A signal indicating the completion of friction welding is input from.

The friction welding controller 37 controls the rotational speed and angular position of the rotary shafts of the rotary drive servomotor 13 and the feed drive servomotor 21. In the friction welding controller 37, the angular position and the rotation speed of the motor rotating shaft detected by the encoder and the rotation speed sensor attached to the rotation driving servomotor 13 and the supply current value detected by the current sensor are Each is inputted via the friction rotation servo driver 39. Then, based on these input information, a speed command and a position command are determined as signals for controlling the operation of the rotation driving servomotor 13, and output to the friction rotation servo driver 39. The friction rotation servo driver 39 supplies a power current to the rotation driving servomotor 13 according to the input signal. On the other hand, the friction welding controller 37 also controls the feed drive servomotor 21 in the same manner. That is, the speed command and the position command are determined based on the information on the angular position, the rotation speed, and the supply current value input via the pressure contact servo driver 41, and the speed command and the position command are output to the pressure contact servo driver 41. The press-contact servo driver 41 supplies a power current to the feed drive servo motor 21 in accordance with the input signal.

The configuration of the friction welding device according to this embodiment has been described above. Next, the operation of the above device will be described.

When the friction rotation servo driver 39 supplies a power current to the rotation drive servomotor 13 in accordance with a control signal from the friction welding controller 37, the rotation drive servomotor 13 rotates. This rotational force is transmitted to the spindle body 9 via the drive gear 17 and the driven gear 19, and the spindle body 9 rotates while holding the joining member A. As described above, the friction welding controller 37 controls the rotational speed and angular position of the rotary drive servomotor 13. Therefore, according to the output signal of the friction welding controller 37, the spindle body 9 rotates at a predetermined rotation speed ω and an angular position (rotational phase), and stops at a predetermined angular position.

When the press-contact servo driver 41 supplies a power current to the feed-drive servomotor 21 in accordance with a control signal from the friction-pressure contact controller 37, the feed-drive servomotor 21 rotates together with the feed shaft 23.
With the rotation of the shaft 23, an axial driving force acts on the engagement arm 25, and the spindle unit 5 is guided by the spindle slide guide 3 and is driven. As described above, the friction welding controller 37 controls the rotational speed and angular position of the feed drive servomotor 21. Therefore, according to the output signal of the friction welding controller 37, the spindle unit 5 is driven together with the joining member A at a predetermined feed speed v, and is driven.
Move to a predetermined feed position Y.

Here, the rotation driving servo motor 13 and the feed driving servo motor 21 are synchronously controlled. The synchronous control means controlling the rotational speeds and angular positions of both servo motors in association with each other. The rotational speed ω of the spindle body 9 at each time t, the feed position Y, and the feed speed v are set to the set values. The control is performed so that

[Friction Welding Method] Next, the friction welding method of the present embodiment using the friction welding apparatus as described above will be explained. FIG. 3 shows a state of rotational drive and feed drive of the joining member in the present embodiment in a form similar to that of FIG. 4 described above. That is, FIG. 11A shows a time chart of the rotational speed ω of the joining member, and FIG. 9B shows the state of the feed driving of the joining member.

In the figure, at times t0 to t1, the same heating process as in the prior art is performed. In this step, the rotation speed is set to the heat generation rotation speed ωa, and the feed speed is set to the heat generation feed speed va, whereby the joining surfaces of both joining members are softened to a predetermined high temperature state.

Next, at times t1 to t4, the stop preparation step, which is a feature of the present invention, is performed. In this process, time t
From 1 to t3, the rotation speed is reduced from ωa to ω1.
On the other hand, the feed speed is decelerated from va to v * at times t1 to t2, and further decelerated to v1 at time t3. During this period, the feed position is changed from Y1 to Y3.

Where ω1 is the stop preparation rotation speed,
v1 is the stop preparation feed speed. These speeds are set so that the high temperature state (at time t1) in which the joint surface is softened can be maintained. Therefore, by performing the rotation and the pressure contact under such conditions, the rotational load on the servo motor 13 can be reduced more than that in the heating step while maintaining the high temperature state of the joint surface. In the present embodiment, the stop preparation rotation speed ω1 and the stop preparation feed speed v
No. 1 is set to the minimum sustainable temperature of the joint surface.

From time t3 to t4, the stop preparation rotation speed ω
The rotation at 1 and the feed drive at the stop preparation feed speed v1 are continuously performed. This period is set as follows. That is, during deceleration from time t1 to t3, a phase deviation of the rotation driving servomotor 13 occurs due to disturbance such as vibration. The time t4 is set to the time required for the phase deviation to be near zero and stable. From the above,
At time t4, the influence of disturbance during deceleration at times t1 to t3 is absorbed and resolved.

In addition, in the stop preparation step, the feed speed is changed stepwise from time t1 to time t3 as described above. Such settings have the following significance. Time t1
By reducing the feed speed when decelerating the rotation speed from the, the phase deviation of the rotation driving servomotor 13 that occurs during deceleration can be suppressed to a small value. Therefore, an appropriate feed speed v * is set to suppress the phase deviation, and the feed speed is decelerated in stages.

The stop preparation step has been described above. Next, the stop joining process after time t4 will be described. In this step, the rotation driving servomotor 1 is operated at time t4 to t5.
3 is decelerated and stopped to stop the rotation of the spindle body 9. The frictional pressure welding controller 37 controls the stop position of the rotary drive servomotor 13 so that the welding angle between the welding member A and the welding member B reaches a desired set value when the spindle body 9 is stopped. After the rotation driving servomotor 13 is stopped, upsetting is performed in the same manner as in the conventional technique, and the joining member A is fed and driven to the feeding position D.

The friction welding method of this embodiment has been described above. In this friction welding method, the rotation speed and the feed speed are set to the stop preparation rotation speed ω1 and the stop preparation feed speed v1 after the joining surface becomes a high temperature in the heating step.
A stop preparation step is provided focusing on the fact that the high temperature state continues even after deceleration. In the stop preparation process, the rotation load acting on the rotation driving servomotor 13 is significantly lower than that in the heat generation process. Further, the phase deviation of the rotation driving servomotor 13 that occurs during deceleration from time t1 to time t3 is resolved by time t4. In the stop joining process, stop preparation rotation speed ω
Since the deceleration stop from 1 is performed, the inertial force acting on the rotation driving servomotor 13 is small. This inertial force is significantly lower than in the case of abrupt stop from the heat generation rotational speed ωa as in the conventional technique. As described above, in the friction welding method, the rotation drive servomotor 13 can be suddenly stopped in the stop joining process only by controlling the rotation speed of the friction rotation controller 37. Further, the stop positioning of the rotation driving servomotor 13 in the same process can be performed only by the angular position control by the friction rotation controller 37. Therefore, this friction welding method has the following advantages as compared with the prior art.

(1) It is not necessary to provide a mechanical lock mechanism for stopping the rotation driving servomotor 13 at the set position. Therefore, joining of other types of joining members can be performed by one device.

(2) In the stop joining process, the inertial force acting on the rotary drive servomotor 13 is small. Conventionally, since this inertial force is large, a large rotary drive machine has been required. Therefore, in the case of the present embodiment, the device can be downsized, and a larger joining member can be joined with the device of the same size. Further, since a general-purpose electric servomotor or controller can be applied, equipment cost can be reduced.

(3) The rotation load acting on the rotation driving servomotor 13 in the stop preparation step is significantly reduced. Also, the inertial force in the stop joining process is small. Furthermore, an external brake is not required, and there is no influence of vibration caused by operating the external brake. Therefore, the accuracy of the stop positioning of the rotation driving servomotor 13 is high, and the accuracy of the joining angle of both joining members is also high. In addition, since the synchronous control of the rotary drive servomotor 13 and the feed drive servomotor 21 is also facilitated, the pressure contact quality becomes more stable.

A modified example of this embodiment will be described below. The present invention is not limited to friction welding using the electric servomotor as described above. INDUSTRIAL APPLICABILITY The present invention is applicable to all friction welding methods and devices capable of controlling the rotation speed and stop position of a rotary drive machine and also controlling the feed speed and feed position of a joining member feed drive machine.

In the above embodiment, the case where no external brake is used has been described. On the other hand, after the stop preparation step, which is a feature of the present invention, is provided, an external brake may be supplementarily used as needed.

[0051]

According to the present invention, after the heat generation step, the relative rotation speed is reduced to a temperature lower than the heat generation rotation speed and the high temperature state is reduced to the sustainable stop preparation rotation speed, and the control disturbance of the relative angle during deceleration occurs. Since the stop preparation step for continuing the relative rotation at the stop preparation rotation speed is provided until it is eliminated, the rotation load due to the rotation and the pressure contact of the joining member is significantly reduced. Further, the inertial force due to the sudden stop of the joining member in the stop joining process is significantly reduced.

Therefore, a mechanical lock mechanism is not required as a structure for joining both joining members at a desired relative angle, and the versatility of the apparatus is increased. Moreover, since the controllability of the relative angle between the joining members is improved, the accuracy of the joining angle can be improved. Furthermore, since it is not necessary to provide a large-capacity rotary drive device, it is possible to downsize equipment and reduce equipment cost.

Further, according to one aspect of the present invention, in the stop preparation step, the relative rotation speed is decelerated, and the pressure contact force is lower than the heat generation pressure contact force and the high temperature state is reduced to the sustainable stop preparation pressure contact force. It is possible to further reduce the rotational load due to the rotation and pressure contact of the joining member.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of a friction welding device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a system for controlling operations of a rotary drive servomotor and a feed drive servomotor in the friction welding device of FIG.

FIG. 3 is an explanatory view showing a friction welding method of the present invention.

FIG. 4 is an explanatory view showing a conventional friction welding method.

[Explanation of symbols]

1 equipment base, 5 spindle unit, 9 spindle body,
11 chucks, 13 rotation drive servo motors, 21
Feed drive servo motor, 29 fixed clamp, 31,
33 encoder, 37 friction welding controller, 39
Friction rotation servo driver, 41 Servo driver for pressure welding, A joining member, B joining member, v0 heat generation feed speed, v1 stop preparation feed speed, ωa heat generation rotation speed, ω
1 Stop preparation rotation speed.

Claims (3)

[Claims] 1. A friction welding method in which the relative rotational speed, relative angle, and pressure contact force of the joining members are controlled so that both joining members are brought into abutting press contact while rotating relative to each other. A predetermined heat generation rotation speed, the pressure contact force as a predetermined heat generation pressure contact force, a heating step of bringing the joint surfaces of the two joining members to a predetermined high temperature state, and the relative rotation speed lower than the heat generation rotation speed. A stop preparation step of decelerating the high temperature state to a sustainable stop preparation rotation speed, and continuing relative rotation at the stop preparation rotation speed until the control disturbance of the relative angle at the time of deceleration is resolved, and a relative relationship between the two joining members. And a stop welding step of joining the joining members at a desired relative angle by stopping the rotation and controlling the relative angle at the time of the stop. 2. The friction welding method according to claim 1, wherein in the stop preparation step, the pressure contact force is lower than the heat generating pressure contact force and the high temperature state is maintained at the same time as the relative rotation speed is reduced. A friction welding method characterized in that the pressure is reduced to the preparation pressure for stopping. 3. A friction welding device for joining both joining members by the friction joining method according to claim 1, wherein the holding device holds each joining member, and the joining members are joined together. A rotary drive device that relatively rotates, a feed drive device that relatively feeds and drives the two joining members so as to make abutting press contact, a rotation speed and a phase of the rotary drive device, and a feed drive speed of the feed drive device are controlled. A friction welding device, which comprises: