JPH0312981B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for a riveting machine, and particularly to a riveting machine that can automatically rivet by simply inputting processing data. Regarding a control device.

[Conventional technology]

Currently, a motor-driven spindle is supported by penetrating the piston shaft of a hydraulic cylinder connected to a hydraulic power source, and a rivet head molding tool is attached to the lower end of the piston shaft to hold the molding shaft. The spindle is lowered and the lower end surface of the forming shaft is pressed against the upper end surface of the work rivet by the hydraulic pressure acting on the piston shaft, and the spindle is rotationally driven by a motor to form a rivet head on the work rivet. A riveting machine designed to do this is known.

Since the height (length) of the workpiece rivet on the worktable varies widely depending on the product to be machined, it is necessary to adjust the extension stroke of the hydraulic cylinder. A stopper plate is provided around the periphery whose vertical position can be variably set by an indexing motor, etc., and as the piston shaft descends, a member fixedly attached to this comes into contact with the stopper plate, thereby controlling the stroke of the piston shaft. Alternatively, a number of stopper pins of different heights are installed upward on a circular member that can rotate around the piston axis, and the pins are installed downward on a plate-shaped body that moves integrally with the piston axis. A mechanical stroke adjustment mechanism is used in which the lower limit of the stroke is set by protruding and lowering the piston shaft to bring a pin on the piston shaft side into contact with a stopper pin selected by rotation of the circular member. ing.

Also, a plane perpendicular to the hydraulic cylinder (X-
To position the target workpiece rivet with respect to the forming axis by moving the worktable in the Y-plane relative to the rivet head forming tool in the X-Y direction, a ball screw type manual or motor driven A table moving mechanism was used.

[Problem to be solved by the invention]

However, the mechanical stroke adjustment mechanism of the prior art as described above requires extra components such as an indexing motor and a stopper means, and also requires time and effort to adjust the stroke, which is an obstacle to fully automation of riveting work. I was getting used to it. Furthermore, since stepless adjustment of the stroke is difficult, when lowering a work rivet of non-standard length, it is necessary to spend extra effort such as customizing a stopper for this purpose.

Furthermore, the X-Y table movement mechanism using a ball screw has a problem that the movement speed is slow, and when the speed is increased, the positioning accuracy deteriorates and proper riveting becomes impossible. As positioning accuracy decreases, it becomes necessary to lubricate and replace parts.
Costs tended to increase.

Furthermore, since the caulking pressure is set by manually adjusting the operating pressure of the relief valve according to the diameter and material of each riveting work, this also requires time and effort, which hinders the automation of riveting work. .

This invention was made in view of the above circumstances,
The purpose is to be able to accurately adjust the stroke of the main hydraulic cylinder using hydraulic control, and also to accurately control the relative positioning between the work table and the main hydraulic cylinder, that is, X-Y axis control, using hydraulic control. It is an object of the present invention to provide a control device for a riveting machine which is capable of automatically setting the caulking pressure and promoting automation of work.

[Means to solve the problem]

To achieve the above object, the riveting machine control device of the present invention includes, firstly, a motor that is supported by a piston shaft of a main hydraulic cylinder for riveting connected to a hydraulic power source, with its axis passing through the piston shaft; A rivet head forming tool that holds the forming shaft is attached to the lower end of the drive spindle, and the spindle is lowered by the extension action of the main hydraulic cylinder to press the lower end surface of the forming shaft against the upper end surface of the workpiece rivet, and then the piston shaft is pressed. A linear encoder for detecting the axial position of the piston shaft in a control device for a riveting machine that presses the piston shaft with hydraulic pressure and rotates the spindle with a motor to form a rivet head on the workpiece rivet. an electro-hydraulic servo valve inserted into a hydraulic circuit between the hydraulic power source and the main hydraulic cylinder; and processing data setting means for setting processing data for the workpiece rivet;
The output of the linear encoder and the machining data are input and predetermined processing is performed, and based on the results, the electro-hydraulic servo valve is controlled to control the operation of the main hydraulic cylinder to transfer the machining data to the workpiece rivet. The control unit is configured to include a control unit that performs processing according to
In the first configuration, an electromagnetic pressure control valve is provided in the conduit of the pressurization system of the main hydraulic cylinder,
The operating pressure is automatically set by the control section according to each rivet work, and thirdly, in the first or second configuration, the pressure system of the main hydraulic cylinder is A hydraulic pressure detection means is provided in the pipeline, and its output is input to the control unit to monitor the hydraulic pressure, and when the hydraulic pressure does not rise even if the piston moves a predetermined stroke during the extension (pressurization) mode of the main hydraulic cylinder. The fourth method is to judge that the rivet work is missing and stop the pressurization mode and switch to the contraction mode.
In this configuration, a hydraulic pressure detection means is provided in the pressure system conduit of the main hydraulic cylinder and its output is inputted to the control section, and the rivet head forming tool is detachably attached to the lower end of the spindle and can be replaced with a rivet head. It can also be used as a rivet press that can manage the pressure when press-fitting a work rivet by installing a press jig for press-fitting a work rivet into the rivet hole of the rivet workpiece and operating the main hydraulic cylinder in extension mode. It is something that has been made possible by
Fifth, in any one of the first to fourth configurations, an X perpendicular to the spindle;
- A work table that moves relatively within the Y plane to position the work rivet placed thereon, and an X-axis hydraulic cylinder and a Y-axis hydraulic cylinder that move the work table within the X-Y plane. , an X-axis linear encoder and a Y-axis linear encoder for detecting the relative position in the X-Y plane between the piston axis of the main hydraulic cylinder and the work table; The controller includes an electrohydraulic servo valve inserted into a hydraulic circuit between the Y-axis hydraulic cylinder and the Y-axis hydraulic cylinder, and the control unit inputs the outputs of the X-axis and Y-axis linear encoders and the processing data to perform predetermined processing. A configuration is adopted in which the operation of the X-axis and Y-axis hydraulic cylinders is controlled by controlling each of the electro-hydraulic servo valves based on the results, thereby machining the workpiece rivet according to the machining data. This is what I did.

[Effect]

In the control device for the riveting machine of the present invention according to the first configuration, the control section automatically calculates the extension stroke of the hydraulic cylinder according to processing data such as the length of the workpiece rivet, and the output of the linear encoder is adjusted accordingly. The servo valve is operated in the direction of lowering the piston shaft of the hydraulic cylinder until it indicates that the lower limit of the stroke has been reached (extension mode);
When the piston shaft reaches the lower limit, the servo valve is switched to the opposite position to raise the piston shaft (retraction mode). When the output of the linear encoder reaches the upper limit position, the servo valve is returned to the neutral position at that position, the hydraulic cylinder is stopped, and the machine waits for the next workpiece riveting process.

As described above, in the riveting machine control device of the present invention, the hydraulic pressure for pressing a work rivet through the forming shaft of the rivet head forming tool attached to the lower end of the spindle shaft during rivet head forming is controlled in accordance with the output signal of the linear encoder. Since it is also used for positioning the spindle shaft by controlling the stroke, mechanical stroke adjustment means are not required.

Further, in the case of the control device for the riveting machine of the present invention having the second configuration, the operating pressure of the electromagnetic pressure control valve is automatically set by the control section according to a program according to the diameter, material, etc. of the workpiece rivet. As a result, riveting work can be automatically performed using a caulking pressure suitable for each workpiece rivet. According to the third configuration, it is further possible to automatically detect the presence or absence of a workpiece rivet at a predetermined processing position, thereby improving the accuracy of rivet processing. According to the fourth configuration,
The riveting machine controlled by the control device of the present invention can be used as a hydraulically controlled riveting press having the operational features of the first or second configuration.

Furthermore, according to the control device for a riveting machine of the present invention having the fifth configuration, the control section controls the stroke in the expansion/contraction direction (Z-axis direction).
In addition to performing the same operations as the control device of the fourth configuration, the positioning control of the work table is also performed using the X-axis servo valve and Y-axis servo valve while feeding back position information from the X-axis linear encoder and Y-axis linear encoder, respectively. Controls the operation of the hydraulic cylinders on each axis. Therefore, rapid positioning is possible without using limit switches or stoppers for positioning on the X-Y plane.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a riveting machine control device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the basic configuration of an embodiment of the present invention, and the control device of the illustrated embodiment moves a control unit 1 and a riveting spindle shaft S (see FIG. 2) in the Z-axis direction (vertical direction). A Z-axis linear encoder 5 is provided on the Z-axis hydraulic cylinder (main hydraulic cylinder) 2 to detect the position of the spindle axis S in the Z-axis direction, and a Z-axis linear encoder 5 is provided in the Z-axis hydraulic cylinder (main hydraulic cylinder) 2 to detect the position of the spindle axis S in the Z-axis direction. The work table W to be placed (see Figure 4) is moved in the X-axis direction and Y-axis direction, respectively.
An X-axis linear encoder 6 and a Y-axis linear encoder 7, which are provided in parallel with the X-axis hydraulic cylinder 3 and Y-axis hydraulic cylinder 4 that are moved in the axial direction, and detect the positions of the work table W in the X-axis direction and the Y-axis direction, and It is composed of a Z-axis servo valve 8, an X-axis servo valve 9, a Y-axis servo valve 10, etc. that control the operations of the Z-axis hydraulic cylinder 2, the X-axis hydraulic cylinder 3, and the Y-axis hydraulic cylinder 4. In the drawing, reference numeral M is a drive motor for the spindle shaft S, P is a hydraulic pump as a hydraulic pressure source, and R is an oil reservoir.

The control unit 1 of this embodiment also includes a host computer 11, an interface 12, a motor control circuit 13 that controls the drive motor M, and the Z-axis servo valve 8, the X-axis servo valve 9, and the Y-axis servo valve 10. It consists of a Z-axis control circuit 14, an X-axis control circuit 15, and a Y-axis control circuit 16, which respectively control the .

A detailed structure of an example of the Z-axis hydraulic cylinder 2 is shown in FIG. 2. The illustrated Z-axis hydraulic cylinder 2 has a spindle shaft S that extends through the axis of a piston shaft 20 and is supported by the piston shaft 20, which is moved up and down by hydraulic oil flowing in and out from ports C and D.
A rivet head forming tool 21 is provided at the lower end of the rivet head. This rivet head forming tool 21 holds a forming shaft 22 with the center of the forming surface at the lower end aligned with the axial center of the spindle shaft S, and the upper end thereof being offset from this axis. Therefore, when the molding tool 21 is rotated by the spindle shaft S, the molding shaft 2
2 forms an inverted conical rotating surface with the molding surface at the lower end as the apex. Also, this Z
A drive motor M is installed above the axial hydraulic cylinder 2 via a spacer 23 , and an output shaft 24 of this drive motor M is coupled to a spindle shaft S via an expansion joint 25 . Of course, the motor M may be moved up and down together with the spindle shaft S by a normal joint without using the expansion joint 25.

In order to perform riveting work using this Z-axis hydraulic cylinder 2, for example, as shown in FIG.
Each rivet (work rivet) B, which is placed on a work table W and whose heads are inserted into holes formed in the riveted product A, is sequentially moved around the spindle shaft S by moving the work table W in the X-Y direction. The spindle shaft S is moved to the axial center position, and the spindle shaft S is lowered together with the piston shaft 20 by a preset stroke. Then, the lower end surface of the forming shaft 22 comes into contact with the upper end surface of the work rivet at a position slightly above the lower limit of the stroke. In this state, the work rivet B is moved by the hydraulic pressure transmitted to the spindle shaft S via the piston shaft 20. When the spindle shaft 20 is rotated by the drive motor M while pressing, the head of the work rivet B is caulked, and when the spindle shaft S reaches the lower limit of its stroke, a rivet head of the desired size is formed, and the spindle is then rotated. The shaft 20 is raised, the work table W is moved again, and processing of the next work rivet B is started.

In this embodiment, the order in which a large number of work rivets B placed on the work table W are processed and the height (length) of each work rivet B are controlled by the host computer 11 of the controller 1.
The host computer 11 calculates the stroke of the spindle shaft S and the movement amount of the work table W according to these setting data, and sends the calculation results to the interface 12.
Instructs the Z-axis control circuit 14, the X-axis control circuit 15, and the Y-axis control circuit 16 via. The motor control circuit 1 also controls the timing for operating the drive motor M.
3. The drive motor M may be operated, for example, throughout the descent of the spindle shaft M (continuous drive is also possible), or from just before the lower end surface of the rivet head forming tool 21 comes into contact with the upper end surface of the workpiece rivet B until it reaches the lower limit of the stroke. All you have to do is make it work only for a while.

When a command is given from the host computer 11, the X-axis control circuit 15 and the Y-axis control circuit 16 change the position of the work table W in the X-axis direction and the Y-axis direction.
Axis linear encoder 6, Y-axis linear encoder 7
The work table W is moved to the position instructed by the host computer 11 by electrically controlling the X-axis servo valve 9 and Y-axis servo valve 10 to operate the X-axis cylinder 3 and Y-axis cylinder 4 while detecting the let As a result, the target workpiece rivet B is aligned with the spindle shaft S of the Z-axis cylinder 2.
Z-axis control circuit 1
4 is the spindle axis S from the Z-axis linear encoder 5
While inputting the position as feedback, the Z-axis servo valve 8 is electrically controlled to operate the Z-axis hydraulic cylinder 2, and the spindle shaft S is lowered to the lower limit of the stroke instructed by the host computer 11.

During this lowering process, the lower end surface of the forming shaft 22 comes into contact with the upper end surface of the workpiece rivet as described above, and while the workpiece rivet B is pressed by the hydraulic pressure transmitted to the spindle shaft S via the piston shaft 20, the workpiece rivet B is pressed by the drive motor M. By rotating the spindle shaft 20, the head of the work rivet B is caulked, and when the spindle shaft 20 reaches the lower limit of its stroke, a rivet head of a desired size is formed. Since reaching this stroke lower limit is fed back by the Z-axis linear encoder 5, the motor control circuit 13 stops the drive motor M, and the Z-axis control circuit 14 switches the Z-axis servo valve 8 to the opposite position to the lowering position, The shaft hydraulic cylinder 2 is operated to raise the spindle shaft S. In FIG. 1, solid line arrows indicate the flow of electrical signals, and thick solid line arrows indicate the flow of hydraulic oil.

Note that FIG. 3 shows an example of the detailed configuration of the Z-axis system. In the illustrated hydraulic system, the Z-axis servo valve 8
is a multi-coil type 4-port 3-position servo valve, which is provided through the piston shaft 20 of the Z-axis cylinder 2, and performs Z-axis control in which the position of the spindle shaft S, which moves up and down together with the piston shaft S, is inputted as feedback by the Z-axis linear encoder 5. Switching the excitation state of the coil excited by the output current of the circuit 14, thereby causing the pressure oil from the oil pump P to flow from either port C or D of the Z-axis hydraulic cylinder P,
It is designed to switch from which side the oil should flow out to the oil reservoir R. Further, the control unit 1
During riveting, the Z-axis hydraulic cylinder 5 is rapidly extended (fast feed) until it approaches the head of the work rivet, and after caulking the head at an appropriate set speed (slow feed), it is moved back (contracted) at high speed again. Controls the Z-axis servo valve 8. In this case, feed speeds such as fast feed and slow feed can be set and controlled steplessly.

In this embodiment, from the Z-axis servo valve 8 to the Z
A pressure sensor 31 that converts the pressure (numeral 30 indicates a pressure gauge) into an electric signal and supplies it to the Z-axis control circuit 14 is connected to the pressure system conduit leading to the C port of the axial hydraulic cylinder 2, and an electromagnetic A pressure control valve (relief valve) 32 is provided. This electromagnetic relief 3
2, that is, the caulking pressure of the Z-axis hydraulic cylinder 2, is automatically set via the Z-axis control circuit 14 according to a program according to each workpiece rivet. Also,
The pressure in the pressurization system of the Z-axis hydraulic cylinder 2 is monitored by the control unit 1 via the pressure sensor 31, and if the hydraulic pressure does not rise even if the piston 20 reaches a predetermined stroke when the Z-axis hydraulic cylinder 2 is in the pressurization mode, The control unit 1 determines that the work rivet is missing. In this way, the presence or absence of rivet work in each rivet hole formed at a predetermined position of the rivet workpiece A can be inspected.
Note that 33 is a relief valve, 34 and 35 are filters, and PM is a pump motor. Also, the X axis,
The Y-axis system can have almost the same configuration as the Z-axis system except for the spindle shaft S, its drive motor M, electromagnetic relief valve 32, etc.
Detailed explanation will be omitted.

Furthermore, the riveting machine control device of the present invention makes the rivet head forming tool 21 at the lower end of the spindle S detachable (see Fig. 2), and presses the work rivet B into the rivet hole of the riveted workpiece A instead of the rivet head. By installing and using a press jig (not shown) for
As a control device for a rivet press, it can also exhibit the excellent control characteristics described above.

In addition, in this invention, if a servo loop of an electrical system and a hydraulic system constituted by electrical and mechanical elements having characteristics as shown in FIG. 5 is used, the position system can be controlled by acceleration = load control. PLL (Phase Locked Loop) can be used to control the servo hydraulic cylinder without any position delay.
It is now possible to control the condition, and the accuracy of riveting processing can be significantly improved.

〔Effect of the invention〕

As explained above, according to the riveting machine control device of the present invention, the hydraulic pressure for pressing the work rivet through the forming shaft of the rivet head forming tool attached to the lower end of the spindle shaft during rivet head forming is controlled by the linear encoder. Since it is also used for positioning the spindle shaft by controlling according to the output signal, there is no need for mechanical stroke adjustment means. By automatically setting the operating pressure of the valve according to a program according to the diameter, material, etc. of the workpiece rivet, riveting work can be automatically performed using a caulking pressure suitable for each workpiece rivet. Further, according to the third configuration, it is further possible to automatically detect the presence or absence of a workpiece rivet at a predetermined processing position,
The accuracy of the riveting process is improved, and according to the fourth configuration, the riveting machine controlled by the control device of the present invention is controlled by a hydraulic control system having the operational characteristics according to the first or second configuration. It can be used as a rivet press.

Furthermore, according to the control device for a riveting machine of the present invention having the fifth configuration, the positioning control of the work table is performed by controlling the X-axis servo while feedbacking position information from the X-axis linear encoder and the Y-axis linear encoder. The operation of the hydraulic cylinders on each axis is controlled by valves and Y-axis servo valves. Therefore, rapid positioning is possible without using limit switches or stoppers for positioning on the X-Y plane.

In particular, according to the present invention, the stroke of the spindle shaft of a riveting machine can be easily and variably set by simply inputting machining data, and the machining according to the settings can be automatically performed with high precision. Therefore, the efficiency and quality of riveting work can be improved to a considerable extent. In addition, the work table can be positioned quickly and with high precision using hydraulic pressure, making riveting work fully automated and labor-saving.Moreover, since no ball screws are used, maintenance effort can be significantly reduced. can.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the basic configuration of an embodiment of a control device for a riveting machine according to the present invention, and Fig. 2 is a sectional view showing an example of the detailed structure of a Z-axis hydraulic cylinder in an embodiment of the invention. , 3rd
The figure is a hydraulic circuit diagram showing an example of the detailed configuration of the hydraulic system in the above embodiment, FIG. 4 is an explanatory diagram of an example of the work table, and FIG. 5 is a loop configuration of the control system in another embodiment of the present invention. It is a block diagram. 1...Control unit (controller), 2...Z-axis hydraulic cylinder (main hydraulic cylinder), 3...X-axis hydraulic cylinder, 4...Y-axis hydraulic cylinder, 5...Z-axis linear encoder, 6...X Axis linear encoder, 7...Y-axis linear encoder, 8...Z-axis servo valve, 9...X-axis servo valve, 10...Y-axis servo valve, 11...Host computer, 13...Motor control circuit, 14 ...Z-axis control circuit, 15...
X-axis control circuit, 16...Y-axis control circuit, 31...
Pressure sensor, 32... Electromagnetic pressure control valve, B... Work rivet, M... Drive motor, S... Spindle shaft, W... Work table.

Claims (1)

[Scope of Claims] 1. A rivet head forming tool that holds a forming shaft is attached to the lower end of a motor-driven spindle that is supported by the piston shaft of a main hydraulic cylinder for riveting that is connected to a hydraulic power source with its axis passing through the piston shaft. ,
The spindle is lowered by the extension action of the main hydraulic cylinder, and the lower end surface of the forming shaft is pressed against the upper end surface of the work rivet by the hydraulic pressure acting on the piston shaft, and the spindle is rotationally driven by the motor. In the control device for a riveting machine, the riveting machine is configured to form a rivet head on the workpiece rivet using: a linear encoder for detecting the axial position of the piston shaft; and a hydraulic circuit between the hydraulic power source and the main hydraulic cylinder. the inserted electro-hydraulic servo valve; a machining data setting means for setting machining data for the workpiece rivet; inputting the output of the linear encoder and the machining data to perform predetermined processing; A control device for a riveting machine, comprising: a control section that controls the operation of the main hydraulic cylinder by controlling a type servo valve to perform processing on the workpiece rivet according to the processing data. 2. Claim 1, characterized in that an electromagnetic pressure control valve is provided in the conduit of the pressurizing system of the main hydraulic cylinder, and its operating pressure is automatically set by the control section according to each work rivet. A control device for a riveting machine described in . 3. A hydraulic pressure detection means is provided in the conduit of the pressurizing system of the main hydraulic cylinder, and its output is input to the control section to monitor the hydraulic pressure, and when the main hydraulic cylinder is in the extension (pressurizing) mode, the piston is in a predetermined position. The rivet according to claim 1 or 2, wherein when the hydraulic pressure does not rise even after the stroke movement, it is determined that the rivet work is missing, and the pressurization mode is stopped and the mode is switched to the contraction mode. control device for the taing machine. 4. A hydraulic pressure detection means is provided in the pressure system conduit of the main hydraulic cylinder, and its output is inputted to the control section, and the rivet head forming tool is detachably attached to the lower end of the spindle, and a work rivet is used instead of the rivet head. By installing a press jig for press-fitting into the rivet hole of the workpiece and operating the main hydraulic cylinder in extension mode, it can also be used as a rivet press that can manage the pressure when press-fitting the workpiece rivet. The riveting machine control device according to claim 1 or 2, characterized in that: 5. A work table that moves relative to the spindle in an X-Y plane perpendicular to the spindle to position the work rivet placed thereon, and a work table for moving the work table in the X-Y plane. An X-axis linear encoder and a Y-axis linear encoder for detecting the relative positions in the X-Y plane between the X-axis hydraulic cylinder and Y-axis hydraulic cylinder, the piston axis of the main hydraulic cylinder, and the work table. and an electro-hydraulic servo valve inserted into a hydraulic circuit between the hydraulic power source and the X-axis and Y-axis hydraulic cylinders, and the control unit controls the output and output of the X-axis and Y-axis linear encoders. The above machining data is input and predetermined processing is performed, and based on the results, each of the electro-hydraulic servo valves is controlled to control the operation of the X-axis and Y-axis hydraulic cylinders, and the workpiece rivet is processed according to the above machining data. The riveting machine control device according to any one of claims 1 to 4, wherein the riveting machine is configured to perform processing.