JPH02229639A - Controller of riveting machine - Google Patents

Abstract

PURPOSE:To execute working which follows working data with respect to a work rivet by inputting an output of a linear encoder and the working data and executing a prescribed processing, and controlling an electrohydraulic servo- valve, based on its result. CONSTITUTION:A control part 1 operates automatically an expanding stroke of a hydraulic cylinder 2 in accordance with working data of length of work rivet B, etc., and until it is shown that an output of a linear encoder 5 reaches the lower limit of its stroke, a servo-valve 8 is operated in the direction for allowing a piston shaft S of the hydraulic cylinder 2 to descend. Thereafter, when the piston shaft S reaches the lower limit, the piston shaft S is allowed to ascend by switching the servo-valve to a reverse position. Subsequently, when the output of the linear encoder 5 reaches a value of the upper limit position, the servo-valve 8 is returned to a neutral position in its position, and brought to holding for working the next work rivet. By controlling hydraulic pressure for pressing the work rivet B in accordance with an output signal of the linear encoder 5, it is used for positioning a spindle shaft, as well.

Description

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

[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 that holds the molding shaft is attached to the lower end of the piston shaft, which extends the hydraulic cylinder. lowers the spindle, presses the lower end surface of the molding shaft against the upper end surface of the work rivet, and presses it with hydraulic pressure acting on the piston shaft, and rotates the spindle with a motor to press the lower end surface of the work rivet against the work rivet. Riveting machines that mold rivet heads are 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 whose vertical position can be variably set by an indexing motor or the like is installed on the piston shaft, and as the piston shaft descends, a member fixedly attached to this comes into contact with the stopper plate, thereby setting the lower limit of the stroke of the piston shaft. Alternatively, a large number of stopper pins of different heights are planted upward on a circular member rotatable around the piston shaft, and a bottle is provided protruding downward from a plate-like body that moves integrally with the piston shaft, A mechanical stroke adjustment mechanism is used in which the lower limit of the stroke is set by lowering the piston shaft and bringing a pin on the piston shaft into contact with a stopper pin selected by rotation of the circular member.

Also, by moving the work table in a plane perpendicular to the hydraulic cylinder (XY plane) relative to the rivet head forming tool in the X-Y direction, the target work rivet is positioned with respect to the forming axis. A ball screw type table movement mechanism driven manually or by a motor 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. It had become. In addition, since stepless adjustment of the stroke is difficult,
When lowering a workpiece rivet with a non-standard length, it is necessary to take 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, and the positioning accuracy is also affected by wear of the ball screw. Since this decreases, labor such as lubrication and parts replacement is required, which tends to increase costs.

Furthermore, the caulking pressure is set by manually adjusting the operating pressure of the relief valve according to the diameter and material of each rivet work, which is time-consuming and hinders the automation of riveting work. Ta.

This invention was made in view of the above circumstances, and its purpose is to accurately adjust the stroke of the main hydraulic cylinder by pressure control, and to control the relative positioning between the work table and the main hydraulic cylinder. That is, it is an object of the present invention to provide a control device for a riveting machine that can accurately control the X-Y axes by hydraulic control, and can also automatically set the caulking pressure, thereby promoting automation of work.

[Means to solve the problem]

In order to achieve the above object, the riveting machine control device of the present invention includes, firstly, a motor drive which is connected to a hydraulic power source or is supported by a piston shaft of a main hydraulic cylinder for betting 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 type 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 the piston shaft In a control device for a riveting machine, the rivet head is pressed by 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. an encoder, an electrohydraulic servo valve inserted in a hydraulic circuit between the hydraulic power source and the main hydraulic cylinder, a machining data setting means for setting machining data of the work rivet, and an output of the linear encoder and the Control that inputs machining data and performs predetermined processing, and controls the operation of the main hydraulic cylinder by controlling the electro-hydraulic servo valve based on the result, thereby machining the workpiece rivet according to the machining data. Second, in the first configuration, an electromagnetic pressure control valve is provided in the conduit of the pressurizing system of the main hydraulic cylinder, and the operating pressure is controlled by the control section. Thirdly, in the first or second configuration, a hydraulic pressure detection means is provided in the conduit of the pressurizing system of the main hydraulic cylinder. The hydraulic pressure is monitored by inputting its output to the control unit, and if the hydraulic pressure does not rise even if the piston moves a predetermined stroke during the extension (pressurization) mode of the main hydraulic cylinder, it is determined that the rivet work is missing. The system is configured to stop the pressurization mode and switch to the contraction mode when it is determined that the main hydraulic cylinder is pressurized. A hydraulic pressure detecting means is provided 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 the work rivet is press-fitted into the rivet hole of the rivet workpiece instead of the rivet head. By installing a press jig and operating the main hydraulic cylinder in extension mode, it is possible to manage the pressure when press-fitting a workpiece rivet, and it can also be used as a bed press. Fifth, the above-mentioned first to fourth
In any of the configurations, a work table moves relatively to the spindle in an X-Y plane perpendicular to the spindle to position a work rivet placed thereon; - an X-axis hydraulic cylinder and a Y-axis hydraulic cylinder for movement within the Y plane, and an The control unit includes an axis linear encoder, a Y-axis linear encoder, 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, Input the output of the Y-axis linear encoder and the above processing data, perform the prescribed processing,
Based on the results, each of the electrohydraulic servo valves is controlled to control the operation of the X-axis and Y-axis hydraulic cylinders, thereby machining the workpiece rivet according to the machining data. It is.

[Effect]

In the control device for a 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 calculates the stroke. Operate the servo valve in the direction of lowering the piston shaft of the hydraulic cylinder until the lower limit is reached (extension mode), and when the piston shaft reaches the lower limit, switch the servo valve to the opposite position to lower the piston shaft. Raise (contraction 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 rivet processing.

As described above, in the riveting machine control device of the present invention, when forming the rivet head, 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 is converted into the output signal of the linear encoder. Since it is also used for positioning the spindle shaft by controlling it accordingly, no mechanical stroke adjustment means is required.

Further, in the case of the control device for a 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 unit according to a program according to the diameter, material, etc. of the workpiece rivet. Riveting work can be automatically performed using 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 rivet press having the operational characteristics according to 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 performs stroke control in the expansion/contraction direction (Z-axis direction) in the same manner as the control device having the first to fourth configurations. Regarding the positioning control of the work table, the operation of the hydraulic cylinders of each axis is controlled by the X-axis servo valve and the Y-axis servo valve while feeding back position information from the X-axis linear encoder and the Y-axis linear encoder, respectively. 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 the riveting spindle shaft S (see FIG. 2) of the control unit I1 in the Z-axis direction (vertical direction). A Z-axis linear encoder 5 is installed in the Z-axis hydraulic cylinder (main hydraulic cylinder) 2 and detects the position of the spindle axis S in the Z-axis direction, and an
A workpiece is installed parallel to an X-axis hydraulic cylinder 3 and a Y-axis hydraulic cylinder 4, which are located in the Y plane and move a worktable W (see Fig. 4) on which a workpiece rivet is placed in the X-axis direction and Y-axis direction, respectively. X-axis direction and Y direction of table W
X-axis linear encoder S and Y to detect axial position
Consists of an axis linear encoder 7, and a Z-axis servo valve 8, an X-axis servo valve 9, a Y-axis servo valve 10, etc. that control the operation of the Z-axis hydraulic cylinder 2, X-axis hydraulic cylinder 3, and Y-axis hydraulic cylinder 4. has been done. In the figure, reference numeral M is a drive motor for the spindle shaft S, P is a hydraulic bomb as a hydraulic pressure source, and R is an oil reservoir.

Further, the control unit 1 of this embodiment includes a host computer 1
l, interface 12, a motor control circuit l3 that controls the drive motor M, and a Z-axis control circuit 14 and an X-axis control circuit that control the Z-axis servo valve 8, X-axis servo valve 9, and Y-axis servo valve 10, respectively. 15 Y-axis control circuit 16.

A detailed structure of an example of the two-shaft 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 raised and lowered by hydraulic oil flowing in and out from boats C and D.
At the lower end of this spindle shaft S, a rivet head forming tool 21 is provided. This rivet head forming tool 2I has a forming shaft 22 with the center of the forming surface at the lower end aligned with the axis of the spindle shaft S, and the upper end portion being eccentric from this axis.
is retained. Therefore, when the molding tool 21 is rotated by the spindle shaft S, an inverted conical rotating surface is formed with the molding surface at the lower end of the molding shaft 2% as the apex. Further, a drive motor M is installed above this Z-axis hydraulic cylinder 2 via a spacer 23.
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 using 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. (work rivet)
B is sequentially moved to the axial center position of the spindle shaft S by moving the work table W in the X-Y direction, 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 reppet at a position slightly above the lower limit of the stroke, but in this state, the piston shaft 20
When the drive motor M rotates the spindle shaft 20 while pressing the work rivet B by the hydraulic pressure transmitted to the spindle shaft S via the hydraulic pressure, the head of the work rivet B is caulked and the spindle shaft 20 reaches the lower limit of the stroke. When the rivet head reaches the desired size, the spindle 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 of machining the large number of work rivets B placed on the work table W and the height (length) of each work rivet B are controlled by the controller.
The host computer 11 calculates the stroke of the spindle shaft S and the moving member of the work table W according to these setting data, and sends the calculation results to the interface 12.
It instructs the Z-axis control circuit 14, the X-axis control circuit 15, and the Y-axis control circuit 16 via the. It also instructs the motor control circuit 13 when to operate the drive motor M.

For example, the drive motor M may be operated throughout the descent of the spindle shaft M (continuous drive may be used), or the drive motor M may reach the lower limit of its stroke just before the lower end surface of the rivet head forming tool 2l comes into contact with the upper end surface of the workpiece rivet B. All you have to do is operate it only until then.

When a command is given from the host computer 11, the X-axis control circuit 15 and the Y-axis control circuit 16 control the work table W.
The position in the X-axis direction and Y-axis direction is determined by the X-axis linear encoder 6.
, X while being detected by the Y-axis linear encoder 7.
Axis servo valve 9, Y-axis servo valve 1Cfi - Electrically controlled to operate the X-axis cylinder 3 and Y-axis cylinder 4, and move the work table W to the position instructed by the host computer 11. When the target work rivet B has been moved to the axial position of the spindle shaft S of the Z-axis cylinder 2, the Z-axis control circuit 14 manually controls the position of the spindle shaft S from the Z-axis linear encoder 5 while manually controlling the position of the spindle shaft S. The Z-axis hydraulic cylinder 2 is operated by electrically controlling the servo valve 8, and the spindle shaft S is lowered to the lower limit of the stroke instructed by the host computer 1l.

During this lowering process, the lower end surface of the forming shaft 22 comes into contact with the upper end surface of the work rivet as described above, and the drive motor presses the work rivet B by the hydraulic pressure transmitted to the spindle shaft S via the piston shaft 20. By rotating the spindle shaft 20 by M, 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, and the Z-axis 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 a detailed configuration of a two-axis system. In the illustrated hydraulic system, the Z-axis servo valve 8 is a multi-coil type 4.
The output of the Z-axis control circuit 14, which is composed of a boat 3-position servo valve and is provided through the piston shaft 20 of the Z-axis cylinder 2, and receives feedback input from the Z-axis linear enhancer 5 of the position of the spindle shaft S, which is raised and lowered together with the piston shaft 20. The excitation state of the coil excited by the current is switched, thereby transferring the pressure oil from the oil pump P to the Z-axis hydraulic cylinder P.
It is designed to switch from which of the boats C and D the oil will flow in and from which it will flow out to the oil reservoir R. Further, during riveting, the control unit 1 rapidly extends the Z-axis hydraulic cylinder 5 until it approaches the head of the workpiece rivet (fast feed), and after caulking the head at an appropriate set speed (slow feed) The Z-axis servo valve 8 is controlled to retreat (contract) at high speed. In this case, feed speeds such as fast feed and slow feed can be set and controlled steplessly.

In this embodiment, the pressure (numeral 30 indicates a pressure gauge) is converted into an electrical signal in the pressure system conduit from the two-axis servo valve 8 to the C boat of the Z-axis hydraulic cylinder 2. A pressure sensor 31 that supplies the shaft control circuit 14 and an electromagnetic pressure control valve (relief valve) 32 are provided. The operating pressure of this electromagnetic relief valve 32, 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. In addition, the pressure in the pressurization system of the Z-axis hydraulic cylinder 2 is monitored by the control unit l via the pressure sensor 3l, and the oil pressure does not rise even if the piston 20 reaches a predetermined stroke when the two-axis hydraulic cylinder 2 is in the pressurization mode. And the control section! It is determined 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 8 can be inspected. In addition,
Reference numeral 33 is a relief valve; 34. 35 is a filter, PM
is a bombmoo evening. Also, the X~axis. The Y-axis system can be configured almost the same as the Z-axis system except for the spindle shaft S, its drive motor M1, electromagnetic relief valve 32, etc., and therefore 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 inserts the work rivet B into the rivet hole of the rivet workpiece 8 instead of the rivet head. By attaching and using a press jig (not shown) for press-fitting, the above-mentioned excellent control characteristics can be exhibited as a control device for a rivet press.

In addition, in this invention, if a servo lube for 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 is controlled by acceleration = load control. This makes it possible to control the servo hydraulic cylinder in a PLL (phase-locked loop) state with no position lag, 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 linear encoder controls 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. Since it is also used for positioning the spindle shaft by controlling according to the output signal of the riveting machine, no mechanical stroke adjustment means is required. By automatically setting the operating pressure by the control unit according to a program according to the diameter, material, etc. of the workpiece rivet, riveting work can be automatically performed using the caulking pressure that suits each workpiece rivet. Further, according to the third configuration, it is possible to automatically detect the presence or absence of a workpiece rivet at a predetermined processing position, improving the accuracy of rivet processing, and according to the fourth configuration, the present invention It becomes possible to use the riveting machine controlled by the control device as a hydraulically controlled rivet press having the operational characteristics according to the first or second configuration.

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 using the X-axis linear encoder and the Y-axis linear encoder, respectively.
The operation of the hydraulic cylinders of each axis is controlled by the X-axis servo valve and the Y-axis servo valve while feeding back position information from the axis linear encoder. Therefore, rapid positioning is possible without using limit switches or stoppers for positioning on the X-Y plane.

In particular, according to this invention, the stroke of the spindle shaft of a riveting machine can be easily and variably set simply by inputting machining data, and machining can be automatically performed according to the settings 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.In addition, since ball screws and the like are not used, maintenance efforts 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 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. , FIG. 3 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 of the control system in another embodiment of the present invention. FIG. 2 is a block diagram showing the configuration. l...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, l1...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... Solenoid pressure control valve, B... Work rivet, M... Drive motor, S... Spindle shaft, W... ...Work table.

Claims (5)

[Claims] (1) Attach a rivet head forming tool that holds a forming shaft to the lower end of a motor-driven spindle that is supported by penetrating the piston shaft of the main hydraulic cylinder for riveting that is connected to a hydraulic power source. The spindle is lowered by the extension action of the 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 a control device for a riveting machine that molds a rivet head on the work rivet, a linear encoder detects the axial position of the piston shaft; and a linear encoder is inserted into a hydraulic circuit between the hydraulic power source and the main hydraulic cylinder. an 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 a predetermined process; 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 in accordance with the processing data. (2) An electromagnetic pressure control valve is provided in the conduit of the pressurizing system of the main hydraulic cylinder, and the operating pressure thereof is automatically set by the control section according to each work rivet. A control device for a riveting machine according to claim 1. (3) A hydraulic pressure detection means is provided in the pressure system conduit 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 (pressurization) mode, the piston is According to claim 1 or 2, when the hydraulic pressure does not rise even after the rivet moves by a predetermined stroke, it is determined that the rivet work is missing, the pressurizing mode is stopped, and the mode is switched to the contraction mode. riveting machine control device. (4) providing a hydraulic pressure detection means in the conduit of the pressurization system of the main hydraulic cylinder and inputting its output to the control section;
The rivet head forming tool is detachably attached to the lower end of the spindle, a press jig for press-fitting the work rivet into the rivet hole of the rivet workpiece is attached instead of the rivet head, and the main hydraulic cylinder is operated in an extension mode. 3. The riveting machine control device according to claim 1, wherein the riveting machine control device can be used as a rivet press capable of controlling pressure when press-fitting a workpiece rivet. (5) a work table that moves relatively to the spindle in an X-Y plane perpendicular to the spindle to position a work rivet placed thereon; An X-axis hydraulic cylinder and a Y-axis hydraulic cylinder for movement, and 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 control unit includes an axis linear encoder 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 X-axis and Y-axis linear encoder. The output of the above and the processing data mentioned above are input and predetermined processing is performed, and based on the results, each of the above electro-hydraulic servo valves is controlled to control the operation of the above X-axis and Y-axis hydraulic cylinders, and the operation is performed on the workpiece rivet. 5. The riveting machine control device according to claim 1, wherein the riveting machine is configured to perform processing according to the processing data.