Patent Grant
10875272
This application is a U.S. National Stage of International Application No. PCT/CN2014/000691 filed 21 Jul. 2014, which claims the benefit of Chinese Patent Application No. 201310682896.1 filed 12 Dec. 2013, each herein fully incorporated by reference.
The present invention is generally related to a hydraulic system, a hydraulic platform and a hydraulic platform assembly used in stamping processes. In particular, the present invention relates to an inner-circulating high speed hydraulic system which performs hydraulic actions in high speed with inner circulation, and also relates to an inner-circulating high speed hydraulic platform and an inner-circulating high speed hydraulic platform assembly comprising the inner-circulating high speed hydraulic system.
In stamping processes for packaging and printing industry, a stamping platform of a platen foil stamping machine is desired to maintain a constant paper-pressing time regardless of speeds, and set adaptive pressing times according to different requirements of products to be stamped, thereby achieving hot stamping pictures with high quality. At present, for a mechanical moving-platform consisting of crank shaft and swing-rod transmission mechanism, the dwell time for pressing at a stop point on the platform varies with changing speeds due to its inherent structure. Thus, it is difficult to guarantee quality of prints. While for hydraulic platforms consisting of conventional hydraulic servo systems, its hydraulic system mainly comprises a hydraulic valve, a hydraulic cylinder, a servo valve, an energy storage system, and lines. Such kind of a conventional hydraulic system has numerous components and complicated structures, causing a relatively high maintenance cost and defects of low efficiency and loud noise. Current hydraulic systems in the art can hardly provide hydraulic actions with high speed, high pressure and high precision at the same time. Thus, further improvements are needed.
Accordingly, it is desired to improve moving-platform systems in stamping processes, enabling the moving-platform systems to accurately control the dwell time for pressing at upper and lower stop points of platforms, adjust the length of the dwell time as required, and provide hydraulic actions with high speed, high pressure and high precision at the same time.
Aiming at the above defects, an objective of the present invention is to provide an inner-circulating high speed hydraulic system with simple structure, high efficiency and high precision, an inner-circulating high speed hydraulic platform and an inner-circulating high speed hydraulic platform assembly comprising the inner-circulating high speed hydraulic system by combining servo motor technology with inner-circulating pressing technology.
Based on the above objective, the present invention firstly provides an inner-circulating high speed hydraulic system, comprising: a hydraulic cylinder assembly and a pressure valve assembly, the hydraulic cylinder assembly including a high pressure cylinder, a hydraulic plunger, and a housing, wherein an axial hole disposed at the top of the high pressure cylinder may communicate with a chamber on the top of the hydraulic plunger, wherein at least one radial hole intersecting with the axial hole is also disposed near the top of the high pressure cylinder, wherein the plunger reciprocates in the high pressure cylinder, wherein the housing contains the high pressure cylinder and forms a sealed inner-circulating oil chamber outside, wherein the inner-circulating oil chamber may communicate with the axial hole via the at least one radial hole and in turn communicate with the top of the hydraulic plunger, wherein a compressed air inlet is disposed on the upper portion of the housing and the lower end of the hydraulic plunger is connected to an actuating element; and the pressure valve assembly comprising a pressure servo motor and a pressure plunger, the pressure plunger may be driven by the pressure servo motor to move up and down within the axial hole disposed on the top of the high pressure cylinder.
Preferably, the actuating element is a moving platen of a moving platform.
Preferably, the hydraulic system further comprises a moving platen lifting component connected to the moving platen, and comprising: a lifting servo motor and a lifting mechanism, wherein the lifting mechanism may be driven by the lifting servo motor so that the moving platen may have lifting motion according to a preset lifting curve.
By using the lifting mechanism, the stroke and the stop positions of the moving platen might be accurately controlled.
Preferably, the lifting mechanism comprises a lifting ball screw and a lifting nut engaged with the lifting ball screw for moving, wherein the lifting ball screw is connected to the lifting servo motor while the lifting nut is connected to the moving platen.
Preferably, a driving mechanism may be disposed between the pressure servo motor and the pressure plunger.
Preferably, the driving mechanism comprises a pressure ball screw and a pressure nut engaged with the pressure ball screw for moving, wherein the pressure ball screw is connected to the pressure servo motor while the pressure nut is connected to the pressure plunger.
Preferably, the pressure plunger may be directly driven by the pressure servo motor.
The present invention further provides an inner-circulating high speed hydraulic platform, comprising: an upper fixed platform on which at least one aforementioned inner-circulating high speed hydraulic system is connected; a moving platen lifting assembly connected to an actuating element, comprising a lifting servo motor and a lifting mechanism driven by the lifting servo motor to facilitate the actuating element to perform lifting motion; and a control system for controlling the above components to act in proper time and controlling the servo motors in the inner-circulating high speed hydraulic system to operate synchronously.
Preferably, the lifting mechanism comprises a lifting ball screw and a lifting nut engaged with the lifting ball screw for moving, wherein the lifting ball screw is connected to the lifting servo motor while the lifting nut is connected to the moving platen.
Preferably, the control system comprises a controller and drivers corresponding to the pressure servo motors of the at least one inner-circulating high speed hydraulic system as well as a driver corresponding to the lifting servo motor, wherein the controller is configured to: send actuating commands to the driver corresponding to the lifting servo motor so that the hydraulic plunger is driven to move downward, which in turn brings the actuating element to move downward; when the actuating element stops moving downward, the controller may receive an in-position signal from the driver of the lifting servo motor and send commands to each driver of the pressure servo motors for synchronously running so as to synchronously drive each pressure plunger entering into high pressure oil chambers and sealing the radial holes; send commands to each driver of the pressure servo motors for synchronously reverse running so as to synchronously drive each pressure plunger to synchronously exit the high pressure oil chambers upward; and send commands to the driver of the lifting servo motor for driving the hydraulic plunger to move reversely, which in turn brings the actuating element to move upward.
Preferably, controlling pressure servo motors for synchronously running includes any of parallel control, master-slave control, cross-coupling control, virtual line-shaft control, and relative coupling control.
Preferably, the controller is a PLC or a motion controller.
The present invention further provides an inner-circulating high speed hydraulic platform assembly, comprising: an aforementioned inner-circulating high speed hydraulic platform; a moving platen connected to the actuating element; an upper fixed platform with which the moving platen may contact with zero speed and press against tightly when the actuating element reciprocates to the upper stop point; a lower fixed platform with which the moving platen may contact with zero speed and press against tightly when the actuating element reciprocates to the lower stop point; and a connecting mechanism for connecting and fixing the upper fixed platform and the lower fixed platform, wherein housings of hydraulic cylinder components are fixed to the upper fixed platform, wherein the high pressure cylinder is contained in a via formed in the upper fixed platform and fixed to said upper fixed platform.
Preferably, the connecting mechanism comprises a right wallboard and a left wallboard which are connected between the upper and lower fixed platform.
The present invention further provides another inner-circulating high speed hydraulic platform, comprising:
a lower fixed platform, connected thereon with:
at least one inner-circulating high speed hydraulic system, comprising:
a hydraulic cylinder component, including a high pressure cylinder, a hydraulic plunger, and a housing, wherein an axial hole disposed at the bottom of the high pressure cylinder may communicate with a chamber in the lower portion of the hydraulic plunger, wherein at least one radial hole intersecting with the axial hole is also disposed near the bottom of the high pressure cylinder, wherein the plunger reciprocates in the high pressure cylinder, wherein the housing contains the high pressure cylinder and forms a sealed inner-circulating oil chamber outside, wherein the inner-circulating oil chamber may communicate with the axial hole via the at least one radial hole and further in turn communicate with the chamber in the lower portion of the hydraulic plunger, wherein a compressed air inlet is disposed on the housing and an upper end of the hydraulic plunger is connected to a actuating element; and
a pressure valve component, comprising a pressure servo motor and a pressure plunger driven by the pressure servo motor to move up and down within the axial hole disposed at the bottom of the high pressure cylinder;
a moving platen lifting component connected to the actuating element and comprising a lifting servo motor and a lifting mechanism, wherein the lifting mechanism may be driven by the lifting servo motor to enable the actuating element to perform lifting motion; and
a control system for controlling the above components to act in proper time and controlling the servo motors in the inner-circulating high speed hydraulic system to operate synchronously.
Preferably, the lifting mechanism comprises a lifting ball screw and a lifting nut engaged with the lifting ball screw for moving, wherein the lifting ball screw is connected to the lifting servo motor while the lifting nut is connected to the moving platen.
Preferably, the control system comprises a controller and drivers corresponding to the pressure servo motors of the at least one inner-circulating high speed hydraulic system as well as a driver corresponding to the lifting servo motor, wherein the controller is configured to send actuating commands to the driver corresponding to the lifting servo motor so that the hydraulic plunger is driven to move upward, which in turn brings the actuating element to move upward; when the actuating element stops moving upward, the controller may receive an in-position signal from the driver of the lifting servo motor and send commands to each driver of the pressure servo motors for synchronously running so as to synchronously drive each pressure plunger synchronously entering into high pressure oil chambers and sealing the radial holes; send commands to each driver of the pressure servo motors for synchronously reverse running so as to synchronously drive each pressure plunger to synchronously exit the high pressure oil chambers downward; and send commands to the driver of the lifting servo motor for driving the hydraulic plunger to move reversely, which in turn brings the actuating element to move downward.
Preferably, controlling pressure servo motors for synchronously running includes any of parallel control, master-slave control, cross-coupling control, virtual line-shaft control, and relative coupling control.
Preferably, the controller is a PLC or a motion controller.
The present invention further provides another inner-circulating high speed hydraulic platform assembly, comprising: an aforementioned inner-circulating high speed hydraulic platform; a moving platen connected to the actuating element; an upper fixed platform with which the moving platen may contact with zero speed and press against tightly when the actuating element reciprocates to the upper stop point; and a connecting mechanism for connecting and fixing the lower fixed platform and the upper fixed platform, wherein housings of hydraulic cylinder assemblies are fixed to the lower fixed platform, wherein a pressure valve component passes through a via formed in the lower fixed platform and is fixed to the lower fixed platform.
Preferably, the connecting mechanism comprises a right wallboard and a left wallboard which are connected between the lower and upper fixed platforms.
The inner-circulating high speed hydraulic system in the present invention combines servo motor technology with inner-circulating pressing technology. By means of the hydraulic system in the present invention, hydraulic pumps, servo valves, energy storage systems and all hydraulic lines in conventional hydraulic systems may be eliminated. As the present system does not need all lines and servo valves in conventional technologies, hydraulic loss is very little and operational efficiency is much higher than existing technologies.
Further, with the inner-circulating high speed hydraulic platform in the present invention, inner-circulation and pressurization of hydraulic oil are achieved while the number of components is merely one third of that in conventional moving-platform. A stamping process with a high speed of 8000 sheets/hour and a positional repeatability of ±0.01 mm is able to be realized. Furthermore, accurate control on dwell time for pressing at upper and lower stop points of platforms and adjustment to lengths of dwell time are enabled. Thus, a high quality stamping process is accomplished. Meanwhile, the inner-circulating high speed hydraulic platform is also highly applicable in other stamping devices requiring high speed, high pressure and high precision.
The inner-circulating high speed hydraulic platform assembly in the present invention has a compact structure with decreased overall height, and is easy for transportation.
Other features and advantages of the present invention will become more obvious from the detailed description set forth below when taken in conjunction with the drawings. In the drawings:
In this embodiment, the inner-circulating high speed hydraulic platform comprises four identical inner-circulating high speed hydraulic systems. However, it should be understood that the present invention is not limited to four identical inner-circulating high speed hydraulic systems, but may have any appropriate number of systems, such as 2, 3, etc. Those four identical inner-circulating high speed hydraulic systems have same structures and operational processes. Herein, only one of the systems is described in details with reference to
The hydraulic cylinder component includes: a high pressure cylinder 11, a hydraulic plunger 15, and a housing 6. An axial hole, disposed on the top of the high pressure cylinder 11, may communicate with a chamber on the top of the hydraulic plunger 15. At least one radial hole(s) 12 intersecting with the axial hole is also disposed near the top of the high pressure cylinder 11. The plunger 15 reciprocates in the high pressure cylinder 11 and the lower end of the plunger 15 may connect to an actuating element, which in a preferred embodiment is a moving platen 16. The housing 6 contains the high pressure cylinder and forms a sealed inner-circulating oil chamber outside. The inner-circulating oil chamber may communicate with the axial hole with the aforementioned at least one radial hole 12 and in turn communicate with the top of the hydraulic plunger 15. In addition, a compressed air inlet 7 is disposed in the upper portion of the housing 6 for introducing compressed air.
A pressure valve component comprising a pressure servo motor 5 and a pressure plunger 10 is disposed on the top of the hydraulic cylinder component. The pressure plunger 10 may be driven by the pressure servo motor 5 to move up and down within an axial hole disposed on the top of the high pressure cylinder 11. In this embodiment, a driving mechanism may be disposed between the pressure servo motor 5 and the pressure plunger 10. The driving mechanism comprises a pressure ball screw 8 and a pressure nut 9 engaged with the pressure ball screw 8 for moving. The pressure ball screw 8 is connected to the pressure servo motor 5 and supported by a bearing to rotate. The pressure nut 9 is connected to a pressure plunger 10.
It should be understood that the pressure plunger 10 may be directly driven by servo motor 5, if desired.
The functions of the pressure valve component are as follows. The pressure servo motor 5 enables the pressure plunger 10 to appropriately turn off hydraulic oil in at least one radial hole 12 of the hydraulic cylinder component according to command(s) received from the control system, which in turn enables the pressure plunger 10 to move into the high pressure oil chamber 22 at the top of the hydraulic plunger 15. When the pressure plunger continues to move downward, the low pressure hydraulic oil 21 in the top of the hydraulic plunger 15 will be compressed, which will increase the pressure in the seal chamber (up to 400 kg/cm2) and generate a significant thrust on the hydraulic plunger 15. Provided that the moving distance of the pressure plunger 10 toward the hydraulic plunger 15 is controlled, the generated thrust of the hydraulic plunger 15 and its highly precise position (for example, with a positional repeatability of ±0.01 mm) may be controlled.
The moving platen lifting component enables the moving platen 16 to approach the fixed platform with high speed and zero-speed contact with the fixed platform with high precision and press it tightly. Meanwhile, the hydraulic plunger 15 fixed on the moving platen 16 is pulled to have oil supplied or discharged from the high pressure hydraulic cylinder 11 thereon.
Hereinafter, the action process of the hydraulic system according to a preferred embodiment of the present invention will be described with respect to
In
With reference to
With reference to
At this time, the lifting servo motor 20 rotates reversely, bringing the moving platen 16 together with the plunger 15 to move upward so that the hydraulic oil 21 may be completely discharged via the radial holes 12. Thus, all actions within a stroke are completed. Then, the platform returns back to the state shown in
In addition to the inner-circulating high speed hydraulic platform, a lower fixed platform 17, a right wallboard 14 and a left wallboard 14A are also illustrated in
Further,
Next, the operational process of the inner-circulating high speed hydraulic platform under the control of the control system will be descried with reference to
With reference to
With reference to
Although the present invention is described with reference to a first embodiment of an inner-circulating high speed hydraulic platform comprising four inner-circulating high speed hydraulic systems, the number of the inner-circulating high speed hydraulic systems in the present invention is not limited to four, but may be any number more than one.
It should be understood that the controller described herein may be implemented as a well known controller in the art, such as PLC, motion controller, and so on.
Descriptions regarding “upward/upper” and “downward/lower” used herein are not intended to limit the direction of components in figures during usage. It will be understood by those skilled in the art that the above system may be used inversely by modification, as will be describe with respect to the second embodiment below.
In this embodiment, the inner-circulating high speed hydraulic platform comprises four identical inner-circulating high speed hydraulic systems. However, it should be understood that the present invention is not limited to four identical inner-circulating high speed hydraulic systems but may take any appropriate number of systems, such as 2, 3, etc. The four inner-circulating high speed hydraulic systems may have similar structure and operational process to those of the first embodiment. Herein, only one of the systems is described in details with reference to
Taking the hydraulic cylinder component shown in the left side of the
A pressure valve component comprising a pressure servo motor 5 and a pressure plunger 10 is disposed at the bottom of the hydraulic cylinder component. The pressure plunger 10 may be driven by the pressure servo motor 5 to move up and down within an axial hole disposed at the bottom of the high pressure cylinder 11. In this embodiment, a driving mechanism may be disposed between the pressure servo motor 5 and the pressure plunger 10. The driving mechanism comprises a pressure ball screw 8 and a pressure nut 9 which is engaged with the pressure ball screw 8 for moving. The pressure ball screw 8 is connected to the pressure servo motor 5 and supported by a bearing to rotate. The pressure nut 9 is connected to a pressure plunger 10.
It should be understood that the pressure plunger 10 may be directly driven by servo motor 5, if desired.
The functions of the pressure valve component are as follows. The pressure servo motor 5 enables the pressure plunger 10 to appropriately turn off hydraulic oil in at least one radial hole 12 of the hydraulic cylinder component according to command(s) received from the control system, which in turn enables the pressure plunger 10 to move into the high pressure chamber 22 at the bottom of the hydraulic plunger 15. When the pressure plunger 10 continues to move upward, the low pressure hydraulic oil 21 at the bottom of the hydraulic plunger 15 will be compressed, which will increase the pressure in the sealed chamber (up to 400 kg/cm2) and cause a significant thrust on the hydraulic plunger 15. Provided that the moving distance of the pressure plunger 10 toward the top of the hydraulic plunger 15 is controlled, the generated thrust of the hydraulic plunger 15 and its highly precise position (for example, with a positional repeatability of ±0.01 mm) may be controlled.
The moving platen lifting component enables the moving platen 16 to approach the fixed platen with high speed and zero-speed contact with the fixed platen with high precision and press it tightly. Meanwhile, the hydraulic plunger 15 fixed on the moving platen 16 is pulled to have the high pressure hydraulic cylinder 11 thereon oil supplied or discharged.
Hereinafter, the action process of the hydraulic system according to a preferred embodiment of the present invention will be described with respect to
In
With reference to
With reference to
At this time, the lifting servo motor 20 rotates reversely, bringing the moving platen 16 together with the plunger 15 to move downward so that the hydraulic oil 21 may be completely discharged via the radial hole 12. Thus, all actions within a stroke are completed. Then, the platform returns back to the state shown in
In addition to the inner-circulating high speed hydraulic platform, an upper fixed platform 17′, a right wallboard 14 and a left wallboard 14A are also illustrated in
Further,
Next, the operational process of the inner-circulating high speed hydraulic platform under the control of the control system will be descried with reference to
With reference to
With reference to
Although the present invention is described with reference to a second embodiment of an inner-circulating high speed hydraulic platform comprising four inner-circulating high speed hydraulic systems, the number of the inner-circulating high speed hydraulic systems in the present invention is not limited to four, but may be any number more than one.
It should be understood that the controller described herein may be implemented as a well known controller in the art, such as PLC, motion controller, and so on.
Descriptions regarding “upward/upper” and “downward/lower” used herein are not intended to limit the direction of components in figures during usage.
While the present invention is specifically described with respect to the preferred embodiments, it should be understood by those skilled that various changes and modifications could be made on the basis of the aforementioned disclosure without departing from the essential thereof. Thus, the scope of the invention is defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013 1 0682896 | Dec 2013 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2014/000691 | 7/21/2014 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/085648 | 6/18/2015 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2825671 | Huffman | Mar 1958 | A |
| 3304077 | Eaton | Feb 1967 | A |
| 4074624 | Biomstad | Feb 1978 | A |
| 5259345 | Richeson | Nov 1993 | A |
| 20070068399 | Anderson | Mar 2007 | A1 |
| 20080245067 | Rapp | Oct 2008 | A1 |
| 20100307349 | Martin | Dec 2010 | A1 |
| 20150273554 | Yukita | Oct 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 2594644 | Jul 2006 | CA |
| 2656134 | Nov 2004 | CN |
| 1727185 | Feb 2006 | CN |
| 1807903 | Jul 2006 | CN |
| 101074691 | Nov 2007 | CN |
| 102658719 | Sep 2012 | CN |
| 203784023 | Aug 2014 | CN |
| 50037980 | Mar 1975 | JP |
| 20110074018 | Jun 2011 | KR |
| Entry |
|---|
| Chinese Office Action for related Application No. CN201310682896.1 dated May 10, 2016. |
| The International Search Report and Written Opinion for PCT Application No. PCT/CN2014/000691 dated Oct. 15, 2014. |
| Number | Date | Country | |
|---|---|---|---|
| 20160311217 A1 | Oct 2016 | US |
