WO2012055579A1

WO2012055579A1 - A servo hydraulic press

Info

Publication number: WO2012055579A1
Application number: PCT/EP2011/057395
Authority: WO
Inventors: Hakan Demir; Sancar Yorukoglu
Original assignee: Coskunöz Metal Form Makina Endüstri Ve Tic. A.S.
Priority date: 2010-10-27
Filing date: 2011-05-09
Publication date: 2012-05-03
Also published as: EP2632705A1; TR201008886A2; WO2012055579A9; CN103237652A

Abstract

A press comprising at least one cylinder (10); a main servo motor (40) and a first hydraulic pump (41) which is driven by said main servo motor (40), whose one output is connected through hydraulic lines (43, 44, 54) to said upper chamber (14) and whose other output is connected hydraulically through hydraulic lines (43, 44, 54) to said lower chamber (15); one auxiliary servo motor (50) and a second hydraulic pump (51) which is driven by the auxiliary servo motor (50) and whose one output is connected to the lower chamber (15) through a hydraulic line (53, 55) and to the input of said first hydraulic pump (41) through another hydraulic line (53, 43); and an electronic control unit which adjusts the velocities and directions of the main and auxiliary servo motors (40, 50) according to the requirements in the free fall, pressing and return steps.

Description

A SERVO HYDRAULIC PRESS

! present invention relates to servo-hydraulic presses and particularly relates to presses iprising a cylinder body; a piston arm whose one end is connected to the ram; at least ! cylinder with a piston head separating the cylinder body into two parts called upper and er chambers; a main servo motor; and a hydraulic pump which is driven by said main /o motor, whose one output is connected hydraulically through the hydraulic lines related ;aid upper chamber and whose other output is hydraulically connected through hydraulic s related to said lower chamber.

OR ART

:onventional hydraulic presses, in order to produce the pressure force, AC standard motor I pump with variable displacement are used. For rotation speed and power adjustment, /o proportional throttling valves are used. Accordingly, the pump applies oil onto the rider, the output under the cylinder is connected to the servo proportional valve. Thus, the Dunt of oil which is pressed through the valve is controlled by means of the servo portional valve and rotation speed and power adjustment is realized in the presses, vever, there are some disadvantages of this embodiment resulting from servo valve ge. First of all, while the hydraulic oil is passing through servo proportional throttling /es, there becomes pressure loss in the system. Moreover, the oil heats up which is ilied through the gap throttled by the valve and as a result of this heating and cooling le, the viscosity of the oil changes and the performance thereof decreases, and the oil has >e changed periodically. On the other hand, since the AC motors used have high inertias I since they are relatively inefficient, the electric consumption of the system is at a high }|. The systems with servo valves have other disadvantages which are not mentioned e. a result, when servo valve is not used, all of the abovementioned problems are eliminated, irder to realize this, the hydraulic pumps are driven by a servo motor and the hydraulic oil upplied to the cylinders. By means of this, since the hydraulic oil does not pass through throttling valves, it is not heated up to the critical temperature, therefore, there is no need cooling. The oil which does not enter into the heating-cooling cycle can be used 2 times 'e. he present art, there are solutions regarding this. For instance, in the patent application 3240758, a hydraulic press is disclosed which has a cylinder unit comprising two types of rider chambers with different cross sections. In the embodiment here, the hydraulic oil t from the hydraulic pump driven by the servo motor is fed to the cylinder unit through a raulic circuit. In the embodiment disclosed in the patent application US20077010171 1 , a /o motor connected to the pump drives the pump, referring to a signal controlling the drive rient.

:he patent application EP1387090, a servo motor transfers the drive to the hydraulic rider by driving two pumps with different volumes. By means of a direction valve, the Dut of the pumps is controlled and again, thanks to the direction valve, when desired, the Dut of the two pumps can be jointed. Accordingly, the servo motor provides pressure- ition control on the cylinder according to the data it receives from the position information ans. the patent application US2010/0212521 , a press brake is disclosed which functions lout an oil tank and which thus has a compact construction, thanks to the close cycle :tioning capability. In said press brake, the drive is provided to the system by a hydraulic ip driven by a servo motor.

;ides the advantages the abovementioned solutions bring, there is a common idvantage. Since, particularly in cases which require high power; servo motors, pumps I drivers are required which will provide this power. These elements which are out of the idards and which are particularly manufactured increase the cost of the system seriously, ^■eover, during the control of big motors, there may be sensitivity problems. Thus, during free fall, return and pressing processes; rotation speed, flow and power controls can not 'ealized with the desired sensitivity. a result, because of the abovementioned drawbacks, an improvement is required in the ited technical field.

IEF DESCRIPTION OF THE INVENTION

! present invention relates to a novel servo-hydraulic press, in order to eliminate the ivementioned problems and to bring new advantages to the related technical field. object of the present invention is to provide a servo hydraulic press which can function at desired power using servo motors with lower power and using hydraulic pump and ers suitable to these motors. )ther object of the present invention is to provide a servo hydraulic press where rotation ed, flow and power controls in free fall, pressing and return stages can be realized in a sitive manner. fder to realize all of the abovementioned objects and the objects which are to be obtained n the detailed description below, the present invention is a press comprising at least one rider with a cylinder body, a piston arm whose one end is connected to the ram, a piston id separating the cylinder body into two parts called upper and lower chambers; a main /o motor; and a hydraulic pump which is driven by said main servo motor, whose one Dut is connected hydraulically through said hydraulic lines related to said upper chamber I whose other output is connected hydraulically through hydraulic lines related to said er chamber; characterized by comprising at least one auxiliary servo motor; a hydraulic ip which is driven by at least one said auxiliary servo motor and whose one output is nected to the lower chamber through a hydraulic line and whose other output is nected hydraulically to the input of said hydraulic pump through another hydraulic line; I an electronic control unit which adjusts the velocities and directions of the main and iliary servo motors according to the requirements in the free fall, pressing and return

DS. i preferred embodiment of the subject matter invention, there is an oil tank connected raulically to the related output of the hydraulic pump which is driven by the auxiliary servo :or. mother preferred embodiment of the subject matter invention, said electronic control unit is not energize the main and the auxiliary servo motor in the free fall step. mother preferred embodiment of the subject matter invention, in the pressing step, said Tronic control unit operates the main servo motor so that the oil in the lower chamber is tioned by the related hydraulic pump and so that said oil is applied to the upper chamber; I said electronic control unit operates the auxiliary servo motor so that the oil in said oil < is suctioned by the related hydraulic pump and so that said oil is applied to the tioning of the hydraulic pump driven by the main servo motor through the related raulic line. another preferred embodiment of the subject matter invention, in the return step, the Tronic control unit operates the main servo motor so that the oil in the upper chamber is tioned by the related hydraulic pump and so that said oil is applied to the lower chamber; I said electronic control unit operates the auxiliary servo motor so that the oil in said oil < is suctioned by the related hydraulic pump and so that said oil is applied to the lower mber through the related hydraulic line. mother preferred embodiment of the subject matter invention, there is a second cylinder ch is connected to the other end of the ram ; an additional main servo motor; an additional raulic pump which is driven by said additional main servo motor and whose one output is nected to the upper chamber of the second cylinder through a hydraulic line and whose 3r output is connected to the lower chamber of the second cylinder through another raulic line and in relation to these, there is an additional auxiliary servo motor; an litional hydraulic pump which is driven by said additional auxiliary servo motor and whose ! output is connected to the lower chamber through a hydraulic line and whose other Dut is connected to the input of the related hydraulic pump through another hydraulic line. mother preferred embodiment of the subject matter invention, said electronic control unit is not energize the main and the auxiliary servo motor in the free fall step. mother preferred embodiment of the subject matter invention, there is an oil tank which is ited to the hydraulic pump driven by said auxiliary servo motor. mother preferred embodiment of the subject matter invention, in the pressing step, said Tronic control unit operates the main servo motor so that the oil in the lower chamber is tioned by the related hydraulic pump and so that said oil is applied to the upper chamber I said electronic control unit operates the auxiliary servo motor so that oil in said oil tank is tioned by the related hydraulic pump and so that said oil is suctioned by the hydraulic ip driven by the main servo motor through the related hydraulic line. another preferred embodiment of the subject matter invention, in the return step, the Tronic control unit operates the main servo motor so that the oil in the upper chamber is tioned by the related hydraulic pump and so that said oil is applied to the lower chamber I said electronic control unit operates the auxiliary servo motor so that oil in said oil tank is tioned by the related hydraulic pump and so that said oil is applied to the lower chamber lugh the related hydraulic line. mother preferred embodiment of the subject matter invention, the electronic control unit fates the main servo motor related to the first cylinder according to the position data 3ived from a related end of the ram and the auxiliary servo motor is synchronized with the n servo motor. mother preferred embodiment of the subject matter invention, the electronic control unit fates the main servo motor related to the second cylinder so that the position data 3ived from the opposite end of the ram will be equal to the position data received from the 3r end, and the electronic control unit synchronizes the auxiliary servo motor regarding second cylinder with the main servo motor. another preferred embodiment of the subject matter invention, there are motor drivers ch drive each servo motor and which provide communication with the electronic control der for the embodiment of the subject matter invention and the advantages thereof 3ther with the additional members to be understood in the best manner, it has to be luated with the annexed figures whose description is given below.

IEF DESCRIPTION OF THE FIGURES

^:igure 1 , the representative block schema of the subject matter servo-hydraulic press is

ΪΠ. ^rigure 2a, 2b and 2c, the representative views of the different operating steps of the ject matter servo-hydraulic press are given.

FERENCE NUMBERS

-irst cylinder 60 Safety valve

Cylinder body 61 Oil tank

^iston head 62 Hydraulic line

^iston arm 70 Main servo motor

Jpper chamber 71 Hydraulic pump

_ower chamber 72 Oil tank

Second cylinder 73 Hydraulic line

Cylinder body 74 Hydraulic line

^iston head 80 Auxiliary servo motor

^iston arm 81 Hydraulic pump Jpper chamber 82 Oil tank

_ower chamber 83 Hydraulic line

³re filling valve 84 Safety valve

— i 11 i ng tank 85 Hydraulic line

vlain servo motor 90 Safety valve

Hydraulic pump 91 Oil tank

Dil tank 92 Hydraulic line

Hydraulic line 100 Safety lock

Hydraulic line 1 10 Ram

Auxiliary servo motor 1 1 1 Locking extension

Hydraulic pump

Dil tank Z1 : Position data

Hydraulic line Z2: Position data

Safety valve

Hydraulic line

Ξ DETAILED DESCRIPTION OF THE INVENTION this detailed explanation, the subject matter servo-hydraulic press is explained with !rences to examples without forming any restrictive effect in order to make the subject 'e understandable. h reference to Figure 1 , in the subject matter invention, the drive to the ram (1 10) is ferably supplied by the two cylinders (10, 20). The piston arm (13, 23) of each cylinder (10, is connected to one end of the ram (1 10). Since the system is symmetric, the details arding only one cylinder (10) will be given below. The cylinder (10) which is used as the e element has a cylinder body (1 1 ); a piston arm (13) whose one end is connected to the I (1 10); and a piston head (12) which is connected to a piston arm (13) moving /nwardly and upwardly inside the cylinder body (1 1 ). Said piston head (12) separates the rider body (1 1 ) into two compartments called upper and lower chambers (14, 15). The ier chamber (14) is hydraulically connected to a filling tank (31 ) through a pre filling valve )■ he system, as a drive source, there is a main servo motor (40); a hydraulic pump (41 ) en by said main servo motor (40); and an auxiliary servo motor (50); and a hydraulic ip (51 ) driven by said auxiliary servo motor (50). One output of the hydraulic pump (41 ) ch is driven by the main servo motor (40) is hydraulically connected to the cylinder upper mber (14) through a hydraulic line (44) and the other output thereof is connected raulically to the lower chamber (15) through another hydraulic line (43, 53). One output of hydraulic pump (51 ) driven by the auxiliary servo motor (50) is hydraulically connected to lower chamber (15) through the related hydraulic lines (53, 55) and the other output 'eof is hydraulically connected to an oil tank (42). On the other hand, there is a safety ^e (54) in the system which is connected in a serial manner to the hydraulic line opened to lower chamber (15); there is another safety valve (60) which is connected in a parallel iner to the hydraulic line (44) which is opened to an upper chamber; and there is an oil

< (61 ) at the output of said safety valve (61 ). in the first cylinder (10), the second cylinder (20) also has a cylinder body (21 ); a piston I (23) whose one end is in connection with the other end of the ram; and a piston head (22) ch separates the cylinder inner volume into upper and lower chambers (24, 25). Again, upper chamber (24) of the second cylinder (20) is hydraulically connected to a filling tank ) through a pre filling valve (30). So as to be a symmetric of the system regarding the first rider (10), a main servo motor (70) is used which drives a hydraulic pump (71 ) as the drive rce of the second cylinder (20) and another auxiliary servo motor (80) is used which es another hydraulic pump (81 ). The hydraulic lines (73, 74, 83, 85) hydraulically connect second cylinder (20) and said hydraulic pumps (71 , 81 ) in the same manner as the :hanism in the first cylinder (10). On the other hand, there is a safety valve (84) which is nected to the hydraulic line (85) in a serial manner, and there is another safety valve (90) ch is connected to the other hydraulic line (74) in a parallel manner, and there is an oil

< (91 ) at the output of said safety valve (90). iddition to the abovementioned details, as a safety precaution known in the art, there is a ung extension (1 1 1 ) which extends upwardly from the middle part of the press ram (1 10), I there is a safety lock (100) which interacts with said locking extension (1 1 1 ). ter the light of the structural details mentioned above and under the light of Figure 2a, 2b I 2c, the operation of the subject matter invention is as follows. Since the operation iner is the same, first of all, the explanation below is realized so as to cover the members arding the first cylinder (10). As known, the pressing process essentially is completed in 3 DS including the free fall process, pressing process and return process and all of these cesses are realized by an electronic control unit (not illustrated in the figure) integrated to system controlling all of the valves and servo motors in the system in a suitable manner. lordingly, during free fall, first of all, the pre filling valve (30) is opened by a pilot pressure I the oil in the filling tank (31 ) begins discharging to the upper chamber (14) of the cylinder L free manner. While oil is filling the upper chamber (14), the oil which exists in the lower mber (15) reaches the hydraulic pump, which is related to the auxiliary servo motor (50), lugh the hydraulic line (55) and through the hydraulic line (53) extending at the tinuation of this line respectively and afterwards, said oil discharges to the oil tank (52), the other hand, it reaches the hydraulic pump (41 ) related to the main servo motor (40) lugh another hydraulic line (43) and afterwards, it reaches the upper chamber (24) lugh the hydraulic line (44) opened to the upper chamber (24). Thus, at a certain speed, ram of the press begins downward movement. On the other hand, with the rotation of the raulic pumps (41 , 51 ), the main and the auxiliary servo motors (40, 50) begin rotating lout consuming power. Thanks to the braking power formed, the free fall of the ram (1 10) omes controllable, and it becomes possible to produce power from this movement of the /o motors by means of the methods known in the art. The produced power is stored by ans of a capacitor when desired or it can be transferred to the present system or to ither system through the frequency converter unit.

! free fall of the ram continues up to a point determined in the position sensor (not itrated in the figure) and afterwards, the pressing process begins by closing the pre filling /e (30). Accordingly, the hydraulic pump (51 ) which is began to be driven by the auxiliary /o motor (50) suctions the oil in the oil tank (52) back and the hydraulic pump (51 ) begins iping the oil to the suctioning port of the hydraulic pump related to the main servo motor ) through the related hydraulic line (43). Meanwhile, the hydraulic pump (41 ) which is ited in the suitable direction by the main servo motor (40) also begins suctioning the oil in lower chamber (15) through the related hydraulic lines (55, 43). Thus, the oil coming from lower chamber (15) and the oil tank (52) joins with the related hydraulic line (43) and it 3rs into the suctioning of the related hydraulic pump (41 ). This hydraulic pump (41 ) ssurizes the arriving oil more, and it applies this oil to the upper chamber (14) of the rider through the related hydraulic line (44). Thus, the desired pressing power is obtained.

;r the pressing process ends, the rotation direction of the main and the auxiliary servo :or (40, 50) is changed and thus, the return process is started. Accordingly, during return, hydraulic pump driven by the main servo motor (40) starts applying the oil in the upper mber (14) of the cylinder to the lower chamber (15) through the related hydraulic line (44,

55). At the same time, the hydraulic pump (51 ) driven by the auxiliary servo motor (50) •lies the oil in the oil tank (52) to the lower chamber (15) through the related hydraulic s (53, 55) and the other hydraulic pump (41 ) applies the oil in the upper chamber (14) or he tank (52) to the lower chamber (15), thus, the ram (1 10) can return back in a rapid iner. During return, the pre filling valve (30) is open, thus, the oil remaining in the upper mber (14) is transferred to the filling tank (31 ). Since the operation manner of the second rider (20) is the same as the operation manner of the first cylinder, it will not be given in ail here.

! synchronization of the servo motors related to the first and the second cylinders (10, 20) )referably as follows. The electronic control unit operates the main servo motor (40) arding the first cylinder (10) according to the position data (Z1 ) obtained from one related I of the ram (1 10) and the auxiliary servo motor (50) is synchronized with the main servo :or (40). On the other hand, the electronic control unit operates the main servo motor (40) arding the second cylinder (20) so that the position data (Z2) obtained from the opposite I of the ram (1 10) will be equal to the other position data (Z1 ); the auxiliary servo motor ) regarding the second cylinder is controlled by being synchronized with the main servo :or (70) here. The revolution proportions between all of the servo motors (40, 50, 70, 80) the system are adjusted according to the selected motor types and application uirements and they drive the servo motors (40, 50, 70, 80) according to these values defined in the electronic control memory. On the other hand, as known in the art, the Tronic control unit controls each servo motor (40, 50, 70, 80) through the motor driver (not itrated in the figure) of that servo motor. a result, thanks to the subject matter system, particularly the pressing and the return cesses can be realized with the same efficiency by using two small standard servo motors I hydraulic pumps related to these motors instead of using a big servo motor which has a 1 cost, which requires particular production and instead of using a hydraulic pump ordingly. Moreover, all of the pressing steps can be controlled in a sensitive manner by jsting the rotation speed and direction of the servo motors in a suitable manner. In more ails, in free fall, the servo motors can be operated with maximum revolution and maximum ed; in pressing process, it can be operated with maximum pressure and thus maximum |ue; and in return process, the servo motors can be operated as in the free fall process with the opposite direction in a controllable and sensitive manner.

Claims

A press comprising at least one cylinder (10) with a cylinder body (1 1 ), a piston arm (13) whose one end is connected to the ram (1 10), a piston head (12) separating the cylinder body (1 1 ) into upper and lower chambers (14, 15); a main servo motor (40); and a hydraulic pump (41 ) which is driven by said main servo motor (40), whose one output is connected hydraulically through hydraulic lines (43, 44, 54) related to said upper chamber (14) and whose other output is connected hydraulically through hydraulic lines (43, 44, 54) related to said lower chamber (15); characterized by comprising at least one auxiliary servo motor (50); a hydraulic pump (51 ) which is driven by at least one said auxiliary servo motor (50) and whose one output is connected to the lower chamber (15) through a hydraulic line (53, 55) and whose other output is connected hydraulically to the input of said hydraulic pump (41 ) through another hydraulic line (53, 43); and an electronic control unit which adjusts the speed and directions of the main and auxiliary servo motors (40, 50) according to the requirements in the free fall, pressing and return steps.

A press according to Claim 1 , characterized by comprising an oil tank (52) connected hydraulically to the related output of the hydraulic pump (51 ) which is driven by the auxiliary servo motor (50).

A press according to Claim 1 , characterized in that said electronic control unit does not energize the main and the auxiliary servo motor (40, 50) in the free fall step.

A press according to any of the preceding claims, characterized in that, in the pressing step, said electronic control unit operates the main servo motor (40) so that the oil in the lower chamber (15) is suctioned by the related hydraulic pump (41 ) and so that said oil is applied to the upper chamber (14); and said electronic control unit operates the auxiliary servo motor (50) so that the oil in said oil tank (52) is suctioned by the related hydraulic pump (41 ) and so that said oil is applied to the suctioning of the hydraulic pump (41 ) driven by the main servo motor (40) through the related hydraulic line (53, 43).

A press according to any of the preceding claims, characterized in that, in the return step, the electronic control unit operates the main servo motor (40) so that the oil in the upper chamber (14) is suctioned by the related hydraulic pump (41 ) and so that said oil is applied to the lower chamber (15); and said electronic control unit operates the auxiliary servo motor (50) so that the oil in said oil tank (52) is suctioned by the related hydraulic pump (51 ) and so that said oil is applied to the lower chamber (15) through the related hydraulic line (53, 55).

6. A press according to Claim 1 , characterized by comprising a second cylinder (20) which is connected to the other end of the ram (1 10); an additional main servo motor

(70) ; an additional hydraulic pump (81 ) which is driven by said additional main servo motor (70) and whose one output is connected to the upper chamber (24) of the second cylinder (20) through a hydraulic line (74) and whose other output is connected to the lower chamber (25) of the second cylinder through another hydraulic line (73, 85) and in relation to these, there is an additional auxiliary servo motor (80); an additional hydraulic pump (81 ) which is driven by said additional auxiliary servo motor (80) and whose one output is connected to the lower chamber (25) through a hydraulic line (83, 85) and whose other output is connected to the input of the related hydraulic pump (71 ) through another hydraulic line (73).

7. A press according to Claim 6, characterized in that said electronic control unit does not energize the main and the auxiliary servo motor (70, 80) in the free fall step.

8. A press according to Claim 6, characterized by comprising an oil tank (82) which is related to the hydraulic pump (81 ) driven by said auxiliary servo motor (80).

9. A press according to any of the claims between Claim 6 and 8, characterized in that in the pressing step, said electronic control unit operates the main servo motor (70) so that the oil in the lower chamber (23) is suctioned by the related hydraulic pump

(71 ) and so that said oil is applied to the upper chamber (24); and said electronic control unit operates the auxiliary servo motor (80) so that the oil in said oil tank (82) is suctioned by the related hydraulic pump (81 ) and so that said oil is applied to the suctioning of the hydraulic pump (71 ) driven by the main servo motor (70) through the related hydraulic line (83, 73).

10. A press according to any of the claims between Claim 6 and 9, characterized in that in the return step, the electronic control unit operates the main servo motor (70) so that the oil in the upper chamber (24) is suctioned by the related hydraulic pump (71 ) and so that said oil is applied to the lower chamber (23) and said electronic control unit operates the auxiliary servo motor (80) so that oil in said oil tank (82) is suctioned by the related hydraulic pump (81 ) and so that said oil is applied to the lower chamber (25) through the related hydraulic line (83, 85).

1 1 . A press according to any of the preceding claims, characterized in that, the electronic control unit operates the main servo motor (40) related to the first cylinder (10) according to the position data (Z1 ) received from a related end of the ram (1 10) and the auxiliary servo motor (50) is synchronized with the main servo motor (40).

12. A press according to any of the preceding claims, characterized in that the electronic control unit operates the main servo motor (70) related to the second cylinder (20) so that the position data (Z2) received from the opposite end of the ram will be equal to the position data (Z1 ) received from the other end, and the electronic control unit synchronizes the auxiliary servo motor (80) regarding the second cylinder with the main servo motor (70).

13. A press according to any of the preceding claims, characterized by comprising motor drivers which drive each servo motor (40, 50, 70, 80) and which provide communication with the electronic control unit.