CA2040365A1 - Controller for work rivet press-fitting machine - Google Patents
Controller for work rivet press-fitting machineInfo
- Publication number
- CA2040365A1 CA2040365A1 CA 2040365 CA2040365A CA2040365A1 CA 2040365 A1 CA2040365 A1 CA 2040365A1 CA 2040365 CA2040365 CA 2040365 CA 2040365 A CA2040365 A CA 2040365A CA 2040365 A1 CA2040365 A1 CA 2040365A1
- Authority
- CA
- Canada
- Prior art keywords
- hydraulic
- hydraulic cylinder
- axis
- work
- piston shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Control Of Presses (AREA)
- Automatic Assembly (AREA)
Abstract
04269-51 RDF:jy ABSTRACT
A controller for a work rivet press-fitting machine has a main hydraulic cylinder for press forming connected with a hydraulic power source and having a piston shaft. The hydraulic cylinder is adapted to extend and retract to press-fit the heads of work rivets in rivet holes formed in a product sheet. The controller includes a linear encoder for detecting the axial position of the piston shaft; an electric/hydraulic servo valve in a hydraulic circuit between the hydraulic power source and the hydraulic cylinder; a machining data setting means for setting machining data for the work rivet; and a control unit receiving the output of the linear encoder and the machining data to perform operations and controlling the hydraulic cylinder by controlling the electric/hydraulic servo valve based on the results of these operations.
A controller for a work rivet press-fitting machine has a main hydraulic cylinder for press forming connected with a hydraulic power source and having a piston shaft. The hydraulic cylinder is adapted to extend and retract to press-fit the heads of work rivets in rivet holes formed in a product sheet. The controller includes a linear encoder for detecting the axial position of the piston shaft; an electric/hydraulic servo valve in a hydraulic circuit between the hydraulic power source and the hydraulic cylinder; a machining data setting means for setting machining data for the work rivet; and a control unit receiving the output of the linear encoder and the machining data to perform operations and controlling the hydraulic cylinder by controlling the electric/hydraulic servo valve based on the results of these operations.
Description
CONT~lOLLER FOR WORK RIVET PRESS-FITTING MACHINE
This invention relates to a controller for a work rivet press-fitting machine for press-fitting work rivets into holes formed in a product sheet such as a plate or a collar.
In riveting operation, it is necessary to insert rivet heads in holes formed in a product sheet before caulking them. This is done by striking the rivets in with a wooden hammer or press-fitting with a hydraulic press.
~ ut since the riveting with a wooden hammer requires human hands, it tends to be costly. Riveting with the hydraulic press has a problem that positioning accuracy is low. Further, due to extremely insufficient stroke and pressure control, when inserting work rivets of different lengths or if the heights of the rivet holes are different, control was impossible. Thus, efficiency was low and automation was impossible.
An object of the present lnvention is to provide a controller ~or a work rivet press-fitting machine which can press-fit work rivets to predetermined heights with high accuracy and which can position the work table carrying a product sheet and the main hydraulic cylinder relative to each other with high accuracy, so that the press-fitting of work rivets can be Farrled ou= un~anned witl less power , - ... , , ~, .. .. . .
consump~ion and in full automation.
Other features and objects of the present invention will become apparent from the following description taken with reference to the accompanying drawings, in which:
Fig. 1 is a block diagram of one embodiment of the controller according to this invention;
Fig. 2 is a sectional view showing one example of the Z-axis hydraulic cylinder;
Fig. 3 is a hydraulic circuit diagram showing one example of the hydraulic system of the above embodiment;
Fig. 4 is an e~planatory view of one example of the work table; and Fig. 5 is a block diagram showing the loop structure of the control system of another embodiment.
Fig. 1 shows the basic structure of preferred embodiment in which the controller shown comprises a control unit 1, a Z-axis linear encoder 5 mounted on a Z-axis hydraulic cylinder 2 for moving a piston shaft 20 for press-fitting work rivets (Fig. 2) in the direction of Z-a~is (vertically) to detect the position of the piston shaft 20 in the direction of Z-axis, and an X-axis linear encoder 6 and a Y-axis linear encoder 7 provided parallel to an X-axis hydraulic cylinder 3 and a Y-axis hydraulic cylinder 4 for moving, respectively, in the directions of X-a~is and Y-axis, a work table W placed on a plane ,,, ,, ~ "
"; , ~:, , ~: " ,~
~Q~
perpendicular to the spindle S and adapted to support a work rivet, so as to detect the position of the work table in the directions of X-axis and Y-axis. The controller further comprises a Z-axis servo valve 8, an X-axis servo valve 9 and a Y-axis servo valve 10 for controlling the Z-axis hydr~ulic cylinder 2, the X-axis hydraulic cylinder 3 and the Y-axis hydraulic cylinder 4, respectively. In the drawings, P is a hydraulic pump as a hydraulic power source, and R is an oil reservoir.
The control unit 1 of this ambodiment comprises a host computer 11, an interface 12 and a Z-axis control circuit 14, an X-axis control circuit 15 and a Y-axis control circuit 16 for controlling the Z-, X- and Y-axis servo valves 8, 9 and 10, respectively.
Fig. 2 shows the detailed structure of an example of the Z-axis hydraulic cylinder 2. It has a piston shaft 20 moved up and down under the action of the hydraulic oil supplied and discharged through ports C and D, respectively. The piston shaft 20 is provided at its bottom end with a rivet chuck 21.
When inserting rivets with the Z-axis hydraulic cylinder 2, as shown in Fig. 4 by way of example, the work table W is moved in the X and Y directions to bring rivet holes formed in a product sheet A placed on the work table W i~to alignment with the piston shaft 20 one after 13~
another. Then the piston.shaft 20 is lowered by a predetermined stroke. The bottom end of the work rivet held by the rivet chuck will be press-fitted into the rivet hole at a point slightly higher than the lower limlt of the stroke, under the hydraulic force transmitted to the spindle S throuOh the piston shaft 20 so that when the piston shaft 20 has reached the lower end of stroke, the rivet chuck 21 opens and the piston shaft 20 is raised and the work table W is moved for the treatment of the ne~t work rivet B.
In this embodiment, the order of press-fitting a plurality of work rivets B in ~he product sheet A and their press-fitting heights are preset in the host computer 11 in the controL unit 1. The host computer 11 calculates the stroke of the piston shaft 20 and the movement of the work table W according to these preset data and gives the results of calculation to the Z-, X- and Y-ax1s control circuits 14, 15 and 16 through the interface 12.
When the X-a3is control circuit 15 and the Y-axis control circuit 16 receive the command from the host computer 11, they will electrically control the X-axis servo valve 9 and the Y-axis servo valve 10, respectively, to activate the X-a2is hydraulic cylinder 3 and the Y-axis hydraulic cylinder 4, while detectin~ the position of the work table W in the X- and Y-axis directions by means of '' ' .. ' ~ , ~
. , . ;,; ., :
- ' 2~03G5 the X- and Y-axis Linear encoders 6 and 7. Thus, the work table ~ is mo~ed to the designated position by the host compu~er 11, so that the target work rivet ~ will be brought in~o alignment with the axis of the spindle S in the Z-a~is hydraulic cylinder 2. Then, the Z-axis control circuit 14 will electrically control the Z-axis servo valve 8 to activate the Z-axis hydraulic cylinder 2, while feeding back the position of the spindle S through the Z-a~is linear encoder 5, so that the spindle S will be lowered to the lower limit of its stroke as commanded by the host computer 11.
The information that the spindle S has reached its lower limit is fed back by the Z-axis linear encoder 5. In response to this information, the Z-a2is servo valve 8 is switched to a position reverse to the descent position by the Z-axis control circuit 14 to actuate the Z-axis hydraulic cylinder 2 so as to raise the spindle S. In Fig.
1, arrows in thin solid lines indicate the flow of electrical signal and the thick lines indicate the flow of hydraulic oil.
Fig. 3 shows the detailed structure of an example o~
the Z-axis system. In the illustrated hydraulic system, the Z-axis servo valve 8 is a double-coil type 4-port, 3-position servo valve. It is adapted to change over the state of ener~ization of che coil ener~ized by the outpu~
~; ' ' .
, - 2~Q!3~5 current from the Z-axis control circuit 14 to which the signal representing the position of the piston shaft 20 is fed back by the Z-axis linear encoder 5. Thus, it is determined which one of the ports C and D in the Z-axis hydraulic c~linder 2 is used to introduce the oil pressure from the hydraulic pump P, in other words, which one is used to discharge the pressure oil into the oil reservoir R. During the press-fitting of work rivets, the control unit 1 controls the Z-axis servo valve 8 in such a way as to extend the Z-axis hydraulic cylinder 2 quickly (fast feed) until it approaches the head o~ the work rivet, extend it at a suitable predetermined speed (slow feed) while caulking the head, and move it backward (shrink) at a high speed again after caulking. In this case, the feed speed can be controlled in a stepless manner.
In this embodiment, the pipe line in the pressure increase system extending from the Z-axis servo valve 8 to the port C in the Z-axis hydraulic cylinder 2 contains a pressure sensor 31 for converting the pressure in the pipe line (numeral 30 indicates a pressure gauge3 into electric si~nals to supply them to the Z-axis control circuit 14, and an electromagnetic pressure control valve (relief valve) 32. The working pressure of the valve 32, i.e. the press-fitting pressure applied by the Z-axis hydraulic cylinder ~ is set automatically by a program through the , .~ - . . , . ~ . .
. :
Z-a~is control circuit 14 according to the respective rivets. Also, the pressure in the pressure increase system of the Z-axis hydraulic cylinder 2 is monitored by the control unit 1 through the pressure sensor 31. If the oil pressure fails to increase even when the piston 20 reaches its predetermined stroke durin~ the pressure increase mode of the Z-a~is hydraulic cylinder ~, the control unit 1 will judge that the work rivet is missing. In this way, it can be checked whether or not a work rivet is in each rivet hole formed in the product sheet A at a predetermined point. Also, pressure can be checked. Numeral 33 designates a relief valve, 34 and 35 do filters and PM
designates a pump motor. The X- and Y-axis systems may be of the same structure as the Z-axis system except that there are not provided the piston shaft 20 and the solenoid relief valve 32. Thus, their detailed description is omitted.
According to this invention, a servo loop for the electric system and the hydraulic system comprising electric and mechanical elements as shown in Fig. 5 may be used to carry out the position control as an acceleration-load control. This arrangement makes it possible to control the servo hydraulic cylinder in a PLL ~phase locked loop) state without any delay in position and thus to remarkably improve the accuracy of riveting work.
_ . , . . ........ .. ... _. . _ . .. _. .. _ ... . . ........ , . , ~ .. _ ' . ' ' -
This invention relates to a controller for a work rivet press-fitting machine for press-fitting work rivets into holes formed in a product sheet such as a plate or a collar.
In riveting operation, it is necessary to insert rivet heads in holes formed in a product sheet before caulking them. This is done by striking the rivets in with a wooden hammer or press-fitting with a hydraulic press.
~ ut since the riveting with a wooden hammer requires human hands, it tends to be costly. Riveting with the hydraulic press has a problem that positioning accuracy is low. Further, due to extremely insufficient stroke and pressure control, when inserting work rivets of different lengths or if the heights of the rivet holes are different, control was impossible. Thus, efficiency was low and automation was impossible.
An object of the present lnvention is to provide a controller ~or a work rivet press-fitting machine which can press-fit work rivets to predetermined heights with high accuracy and which can position the work table carrying a product sheet and the main hydraulic cylinder relative to each other with high accuracy, so that the press-fitting of work rivets can be Farrled ou= un~anned witl less power , - ... , , ~, .. .. . .
consump~ion and in full automation.
Other features and objects of the present invention will become apparent from the following description taken with reference to the accompanying drawings, in which:
Fig. 1 is a block diagram of one embodiment of the controller according to this invention;
Fig. 2 is a sectional view showing one example of the Z-axis hydraulic cylinder;
Fig. 3 is a hydraulic circuit diagram showing one example of the hydraulic system of the above embodiment;
Fig. 4 is an e~planatory view of one example of the work table; and Fig. 5 is a block diagram showing the loop structure of the control system of another embodiment.
Fig. 1 shows the basic structure of preferred embodiment in which the controller shown comprises a control unit 1, a Z-axis linear encoder 5 mounted on a Z-axis hydraulic cylinder 2 for moving a piston shaft 20 for press-fitting work rivets (Fig. 2) in the direction of Z-a~is (vertically) to detect the position of the piston shaft 20 in the direction of Z-axis, and an X-axis linear encoder 6 and a Y-axis linear encoder 7 provided parallel to an X-axis hydraulic cylinder 3 and a Y-axis hydraulic cylinder 4 for moving, respectively, in the directions of X-a~is and Y-axis, a work table W placed on a plane ,,, ,, ~ "
"; , ~:, , ~: " ,~
~Q~
perpendicular to the spindle S and adapted to support a work rivet, so as to detect the position of the work table in the directions of X-axis and Y-axis. The controller further comprises a Z-axis servo valve 8, an X-axis servo valve 9 and a Y-axis servo valve 10 for controlling the Z-axis hydr~ulic cylinder 2, the X-axis hydraulic cylinder 3 and the Y-axis hydraulic cylinder 4, respectively. In the drawings, P is a hydraulic pump as a hydraulic power source, and R is an oil reservoir.
The control unit 1 of this ambodiment comprises a host computer 11, an interface 12 and a Z-axis control circuit 14, an X-axis control circuit 15 and a Y-axis control circuit 16 for controlling the Z-, X- and Y-axis servo valves 8, 9 and 10, respectively.
Fig. 2 shows the detailed structure of an example of the Z-axis hydraulic cylinder 2. It has a piston shaft 20 moved up and down under the action of the hydraulic oil supplied and discharged through ports C and D, respectively. The piston shaft 20 is provided at its bottom end with a rivet chuck 21.
When inserting rivets with the Z-axis hydraulic cylinder 2, as shown in Fig. 4 by way of example, the work table W is moved in the X and Y directions to bring rivet holes formed in a product sheet A placed on the work table W i~to alignment with the piston shaft 20 one after 13~
another. Then the piston.shaft 20 is lowered by a predetermined stroke. The bottom end of the work rivet held by the rivet chuck will be press-fitted into the rivet hole at a point slightly higher than the lower limlt of the stroke, under the hydraulic force transmitted to the spindle S throuOh the piston shaft 20 so that when the piston shaft 20 has reached the lower end of stroke, the rivet chuck 21 opens and the piston shaft 20 is raised and the work table W is moved for the treatment of the ne~t work rivet B.
In this embodiment, the order of press-fitting a plurality of work rivets B in ~he product sheet A and their press-fitting heights are preset in the host computer 11 in the controL unit 1. The host computer 11 calculates the stroke of the piston shaft 20 and the movement of the work table W according to these preset data and gives the results of calculation to the Z-, X- and Y-ax1s control circuits 14, 15 and 16 through the interface 12.
When the X-a3is control circuit 15 and the Y-axis control circuit 16 receive the command from the host computer 11, they will electrically control the X-axis servo valve 9 and the Y-axis servo valve 10, respectively, to activate the X-a2is hydraulic cylinder 3 and the Y-axis hydraulic cylinder 4, while detectin~ the position of the work table W in the X- and Y-axis directions by means of '' ' .. ' ~ , ~
. , . ;,; ., :
- ' 2~03G5 the X- and Y-axis Linear encoders 6 and 7. Thus, the work table ~ is mo~ed to the designated position by the host compu~er 11, so that the target work rivet ~ will be brought in~o alignment with the axis of the spindle S in the Z-a~is hydraulic cylinder 2. Then, the Z-axis control circuit 14 will electrically control the Z-axis servo valve 8 to activate the Z-axis hydraulic cylinder 2, while feeding back the position of the spindle S through the Z-a~is linear encoder 5, so that the spindle S will be lowered to the lower limit of its stroke as commanded by the host computer 11.
The information that the spindle S has reached its lower limit is fed back by the Z-axis linear encoder 5. In response to this information, the Z-a2is servo valve 8 is switched to a position reverse to the descent position by the Z-axis control circuit 14 to actuate the Z-axis hydraulic cylinder 2 so as to raise the spindle S. In Fig.
1, arrows in thin solid lines indicate the flow of electrical signal and the thick lines indicate the flow of hydraulic oil.
Fig. 3 shows the detailed structure of an example o~
the Z-axis system. In the illustrated hydraulic system, the Z-axis servo valve 8 is a double-coil type 4-port, 3-position servo valve. It is adapted to change over the state of ener~ization of che coil ener~ized by the outpu~
~; ' ' .
, - 2~Q!3~5 current from the Z-axis control circuit 14 to which the signal representing the position of the piston shaft 20 is fed back by the Z-axis linear encoder 5. Thus, it is determined which one of the ports C and D in the Z-axis hydraulic c~linder 2 is used to introduce the oil pressure from the hydraulic pump P, in other words, which one is used to discharge the pressure oil into the oil reservoir R. During the press-fitting of work rivets, the control unit 1 controls the Z-axis servo valve 8 in such a way as to extend the Z-axis hydraulic cylinder 2 quickly (fast feed) until it approaches the head o~ the work rivet, extend it at a suitable predetermined speed (slow feed) while caulking the head, and move it backward (shrink) at a high speed again after caulking. In this case, the feed speed can be controlled in a stepless manner.
In this embodiment, the pipe line in the pressure increase system extending from the Z-axis servo valve 8 to the port C in the Z-axis hydraulic cylinder 2 contains a pressure sensor 31 for converting the pressure in the pipe line (numeral 30 indicates a pressure gauge3 into electric si~nals to supply them to the Z-axis control circuit 14, and an electromagnetic pressure control valve (relief valve) 32. The working pressure of the valve 32, i.e. the press-fitting pressure applied by the Z-axis hydraulic cylinder ~ is set automatically by a program through the , .~ - . . , . ~ . .
. :
Z-a~is control circuit 14 according to the respective rivets. Also, the pressure in the pressure increase system of the Z-axis hydraulic cylinder 2 is monitored by the control unit 1 through the pressure sensor 31. If the oil pressure fails to increase even when the piston 20 reaches its predetermined stroke durin~ the pressure increase mode of the Z-a~is hydraulic cylinder ~, the control unit 1 will judge that the work rivet is missing. In this way, it can be checked whether or not a work rivet is in each rivet hole formed in the product sheet A at a predetermined point. Also, pressure can be checked. Numeral 33 designates a relief valve, 34 and 35 do filters and PM
designates a pump motor. The X- and Y-axis systems may be of the same structure as the Z-axis system except that there are not provided the piston shaft 20 and the solenoid relief valve 32. Thus, their detailed description is omitted.
According to this invention, a servo loop for the electric system and the hydraulic system comprising electric and mechanical elements as shown in Fig. 5 may be used to carry out the position control as an acceleration-load control. This arrangement makes it possible to control the servo hydraulic cylinder in a PLL ~phase locked loop) state without any delay in position and thus to remarkably improve the accuracy of riveting work.
_ . , . . ........ .. ... _. . _ . .. _. .. _ ... . . ........ , . , ~ .. _ ' . ' ' -
Claims (3)
1. A controller for a work rivet press-fitting machine having a main hydraulic cylinder for press forming connected with hydraulic power source and having a piston shaft, said hydraulic cylinder being adapted to extend and retract to press-fit the heads of work rivets in rivet holes formed in a product sheet;
said controller comprising;
a linear encoder for detecting the axial position of said piston shaft;
an electric/hydraulic servo valve provided in a hydraulic circuit between said hydraulic power source and said hydraulic cylinder;
a machining data setting means for setting machining data for said work rivet; and a control unit receiving the output of said linear encoder and said machining data to perform operations and controlling said hydraulic cylinder by controlling said electric/hydraulic servo valve based on the results of said operations.
said controller comprising;
a linear encoder for detecting the axial position of said piston shaft;
an electric/hydraulic servo valve provided in a hydraulic circuit between said hydraulic power source and said hydraulic cylinder;
a machining data setting means for setting machining data for said work rivet; and a control unit receiving the output of said linear encoder and said machining data to perform operations and controlling said hydraulic cylinder by controlling said electric/hydraulic servo valve based on the results of said operations.
2. A controller as claimed in claim 1, further comprising a hydraulic pressure detecting means provided in a pipe line of a pressure increase system in said main hydraulic cylinder, the output of said detecting means being inputted in said control unit to monitor whether or not the work rivets are press-fitted in the respective rivet holes under a pressure within a predetermined range.
3. A controller as claimed in claim 1 or 2, further comprising a work table movable relative to said piston shaft on an X-Y plane perpendicular to said piston shaft so as to set the respective rivet holes formed in said product sheet placed thereon in a predetermined position with respect to said piston shaft, an X-axis hydraulic cylinder and a Y-axis hydraulic cylinder for moving said work table on 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 said piston shaft of said hydraulic cylinder and said work table, electric hydraulic servo valves each provided in respective hydraulic circuits between said hydraulic power source and said X- and Y-axis hydraulic cylinders, said control unit being adapted to perform predetermined operations by inputting the output of said X- and Y-axis linear encoders and said machining data and control said X- and Y-axis hydraulic cylinders by controlling said respective electric/hydraulic servo motors based on the results of said operations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2040365 CA2040365A1 (en) | 1991-04-18 | 1991-04-18 | Controller for work rivet press-fitting machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2040365 CA2040365A1 (en) | 1991-04-18 | 1991-04-18 | Controller for work rivet press-fitting machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2040365A1 true CA2040365A1 (en) | 1992-10-19 |
Family
ID=4147390
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2040365 Abandoned CA2040365A1 (en) | 1991-04-18 | 1991-04-18 | Controller for work rivet press-fitting machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2040365A1 (en) |
-
1991
- 1991-04-18 CA CA 2040365 patent/CA2040365A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |