JP2003507664A - Press safety valve - Google Patents

Abstract

(57) SUMMARY The present invention relates to a fluid valve device for controlling a fluid load (80). The device comprises a fluid pressure source (40) by at least one pressure connection (30), a fluid load (80) by at least one working connection (70), and at least one tank connection (30). 50) and is connected to the tank (60). The tank comprises hydraulic fluid. The device of the invention has at least two working valves (90, 140), which are operable by at least one electrically actuable control valve (230). It is an object of the invention to obtain the shortest possible connection and blocking action at the user level (80). For this purpose, at least two working valves (90, 140) are formed as seat valves (110).

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION The present invention relates generally to hydraulic pressure relief valves, and more particularly to a safety valve unit according to the preamble of claim 1 and a buffer valve according to the preamble of claims 9 and 14. A unit and a valve device according to claim 18 having these units, and a press safety valve according to claim 19 having these units.

Fluid pressure relief valves of the type mentioned here are used, for example, for controlling the brakes and / or clutches of mechanical pressing devices. That is, DE3817
From 123A1 there is already known a hydraulic valve for the above-mentioned use, which hydraulic valve is driven by two electromagnetically operated pilot valves. Valve
Furthermore, it has two valve bodies with control pistons which are movable in opposite directions with respect to each other. The control piston allows a pump connection, two working connections and two
The connection between the two tank connections is controlled. If there is a false switch,
The valve body moves to the hydraulically locked end position. In particular, one of the two pilot valves is designed as a proportional differential pressure valve, in which case the control piston associated with it is provided with a precision control notch, so that the valve is adjusted proportionally, Thereby, the pressure build-up, speed and direction of movement of the load connected downstream of the valve can be controlled.

DE 19620468A1 further describes a safety valve in which two side-by-side working pistons are arranged in a housing, each working piston being rigidly connected to a valve disc. There is. The two working pistons are
It is electromagnetically driven by a pilot valve. A supply part is formed in the housing, and the supply part is connected to a compressed air source. The supply section leads to a valve disc, which is crossed and connected to each other by a cross passage. A load, for example a piston drive of a mechanical pressing device, is supplied with pressure in the switching position of the safety valve via the load connection and in the zero position the load is exhausted via the exhaust connection. From the cross passage, a passage branches into each of the pilot valves. In addition, a passage extends from each pilot valve to the associated working piston. Further, each pilot valve is provided with a magnetic coil, and each magnetic coil is connected via a current supply line to a current source which is a part of machine control.

In order to improve the productivity of mechanical loads such as mechanical pressing devices, it is necessary to increase the speed of the piston drive.

Further, there is a gradual transition to integrating the entire press lane into a single large press machine. However, this pressing device requires a correspondingly large clutch / brake unit in order to be able to overcome the high fluid pressure switching volume, in which case the clutch / brake unit is a component unit or It can be placed separately.

The safety valves known from the prior art mentioned above are all formed in piston slide valve technology, which limits their maximum flow rate. Furthermore, this valve requires a long switching time during the clutches and brakes of the press, due to the piston lift required during the switching process.

[0007] SUMMARY It is therefore an object of the present invention of the present invention, it guarantees the shortest possible switching time, especially to allow the shortest possible clutch and braking process to a mechanical pressing device, yet high driving safety as possible at the same time mechanical loading To provide a hydraulic valve device and a press safety valve of the type mentioned at the outset.

This task is solved by the features of independent claims 1 and 14. Preferred embodiments of the invention are the subject of the dependent claims.

According to the invention, in a safety valve unit of the type mentioned at the beginning, at least two working valves are formed as seat valves.

In the case of the buffer valve unit that cooperates particularly with the safety valve unit, in the first variant, a pressure reducing valve is provided which is connected on the pressure connection side in front of the first working valve.

In a second variant, the buffer valve unit has a root valve arranged on the tank connection side and formed as a seat valve.

The seat valve arrangement used in the variant described above allows a particularly high flow rate as well as a very short switching time of this valve. Because of this construction, already slight piston movements result in large valve opening cross sections with almost no time delay.

Brief Description of the Drawings Embodiments of the invention are described below with reference to the drawings, which highlight other features and advantages of the invention. In that case, in the drawings, identical or functionally identical features are provided with corresponding reference numerals.

Detailed Description of the Embodiments FIG. 1 shows two assemblies, in particular a safety valve unit 10 and a buffer valve unit 20.
And a fluid pressure valve device consisting of Both units 10, 20 have a fluid pump 40 via a pressure connection 30 and a fluid tank 60 via a tank connection 50.
And through a working connection 70 to conduct a mechanical load, in this example a fluid and pressure, with a clutch and / or brake piston 80 provided for driving a mechanical pressing device (not shown). It is connected to the. The fluid is not important here. Therefore, it may be gas or liquid.

The safety valve unit 10 has a first 2 / 2-root valve 90 formed of a seat valve structure, in which the piston 1 protruding into the valve chamber 100.
05 forms a valve seat 110 with an annular surface formed inside the valve housing. This valve seat 110 connects or disconnects the pressure conduit 120 emerging from the pressure connection end 30 with the working conduit 130 emerging from the work connection end 70. Two conduits 1
20 and 130 are suspended in the present driving state (closed).

The active movement of the piston 105 to drive the valve 90 is likewise fluidically carried out via the (valve-) control chamber 115. The root valve 90 is further
It has a proximity switch (S3) 95 designed as an induction switch, and the proximity switch can detect the drive state of the root valve 90.

Furthermore, two 2 / 2-route valves 140, 1 also formed of seat valve structures
50 are provided, in which pistons 155, 165, which are substantially abutting against the inner annular surface 170, form a valve seat and are opened by spring biases 180, 190 in the deenergized drive state shown. . Therefore, the route valves 140, 15
0 is in the safe "open" -position, especially in the depleted state, where the working conduit 130 is drained. These valves 140
, 150, the pistons 155, 165 also fluidly control chamber 162,
175 (active). Further, the route valves 140 and 150 also have proximity switches 145 and 155 having the above-described functionality, respectively.

Due to the overall design of the 2 / 2-route valve with a seat valve structure, with a pressure sensor (not shown here) arranged in the region of the respective valve seat, a high speed valve Combined with the switching time, a high driving safety is provided.

The working conduit 130 is connected in parallel to the connection with the first root valve 90 and also with the valve chambers 200, 210 of the two root valves 140, 150, so that
The working conduit 130 is a tank conduit 220 that leads to the fluid tank 60 in this situation.
It is discharged fluidly via.

In order to improve the driving safety of the entire valve device, two 2 / 2-route valves 140 are provided.
, 150 are functionally identical. Furthermore, their parallel connection means a redundancy that further improves the driving safety, so that a reliable braking of the clutch and / or the brake piston 80 is always guaranteed.

As already mentioned, the root valves 90, 140, 150 are respectively pistons 105, 155, 1 driven via control chambers 115, 162, 175.
It is switched by the movement of 65. The control chambers 115, 162, 175 are
To that end, it is connected to a fluidic control conduit system 225, which is shown in phantom in the drawing.

The safety valve unit 10 further comprises pilot valves 230, 240 designed as 4 / 2-route valves, which are switched by electromagnets 235, 245. The pilot valves 230, 240, on the one hand (as shown here), control the control chamber 115 of the first root valve 90 with the pressure conduit 120, and thus also with the pump 40, and the root valves 140, 150. Chamber 162, 1
75 is connected to the tank conduit 220 and thus also to the tank 60. On the other hand(
In the cross position (not shown here), the control chamber 115 is connected to the tank conduit 220 and the control chambers 162, 175 are connected to the pressure conduit 227.

All 2 / 2-route valves 9 driven by the same pilot valves 230, 240
0, 140, 150 make the entire device work in the form of a forced connection, so that the overall drive state is uniquely determined.

The buffer valve unit 20 has a proportional pressure limiting valve 250, which is closed by a spring bias without energization and is adjusted or opened via a control current.
This ensures that the pressing device can be softly braked via the clutch or brake piston 80 even when the current is removed.

The proportional pressure reduction valve 260 allows for pressure modulation during soft clutch and various pressure stages when the press device is engaged by the clutch piston 80.

The pressure limiting valve 270 is used to secure the maximum pressure of the clutch driven by the clutch piston 80. The pressure limiting valve 270 prevents too high operating pressure in the clutch, which may occur, for example, due to accidental actuation of the proportional pressure reducing valve 260.

The damping valve unit then also has a spring energy store 290, which guarantees a permanent counterpressure in the tank conduit, especially during the soft brake mode, and thus the press. Allows controlled braking of the device.

In the following, the functional sequence of the illustrated valve device will be described in detail, in which case also reference is made to FIG. In the basic position shown in FIG. 1, the electromagnets 2 of the pilot valves 230 and 240 are
35 and 245 are not energized. Thereby, the root valves 140 and 150 are switched to the open position by the respective spring biases 180, 190, in which case the induction switches 145 and 155 are buffered. The root valve 90 is closed in the basic position and its inductive switch 95 is unbuffered.

The pump pressure transmitted via the pressure conduit 120 thus acts on the annular surface of the valve piston 105 of the root valve 90. At the same time, the root valve 90 is held in the closed position via the pilot valves 230 and 240 based on the area difference between the two pistons.

There is no connection between the pump connection 30 and the working connection 70 and the tank connection 50, so that the working connection 70 is discharged via the tank conduit 220 and the tank connection 50.

The proximity switch 95 must leave the closed or unbuffered position before it can be moved from the basic position to the switching position. Similarly, the proximity switches 145 and 155S2 must also leave their current open or buffered position.

In the switching position, the electromagnets 235, 24 of both pilot valves 230, 240
5 is excited. Thereby, the part of the control conduit 225 leading to the root valve 90 is discharged towards the tank 60. In addition, the root valves 140 and 150 are closed. In the switching position, the pump connection end 30 is connected to the working connection end 70.
On the other hand, the connection between the working connection end 70 and the tank connection end 50 is broken.

Here, assuming that one of the pilot valves 240, 240 malfunctions, in that case, the electromagnet 245 of the pilot valve 240 is excited and the electromagnet 2 of the pilot valve 230 is excited.
35 is de-excited. Thus, only root valve 150 is closed, while root valve 140 remains open. As a result, the connection between the working connection 70 and the tank connection 50 also remains open. Therefore, no pressure can be built up at the working connection 70, which represents a high safety factor. The erroneous function (erroneous switching) described above is further recognized as an erroneous function by the unequal signal output of the proximity switches 145 and 155 in the control (not shown here).

In order to recognize this kind of or similar malfunction, the switching of the proximity switches 145, 155 is checked periodically during the lifting and lowering of the press.

The buffer valve unit achieves a soft clutch and brake. In the case of a soft clutch, in addition to the pilot valves 230, 240, the electromagnet 265 of the proportional pressure reducing valve 260 is also energized, in which case the latter is driven by current so that the secondary pressure corresponds to the pump pressure. It This ensures that the lift volume flows quickly to the clutch-brake combination. This means a quick response of the clutch.

When the clutch is closed, the current in the proportional-pressure reduction valve 260 is reduced again, causing the secondary pressure to drop to the desired soft clutch pressure. After the acceleration process, the current in the proportional pressure reduction valve 260 is increased again so that the pressure defined for the clutch rises to the nominal pressure.

In the case of soft braking, on the other hand, the electromagnets 235, 245 of the pilot valves 230, 240 are de-energized and the electromagnet 255 of the proportional pressure limiting valve 250 is excited, in which case the latter It is energized so that it opens completely.

The switching volume of fluid generated by the clutch / brake combination then flows out to the tank 60 via the proportional pressure limiting valve 250. Just before the brake closes,
As the current in the proportional pressure limiting valve 250 is reduced again, pressure builds up in the conduit leading to the working connection 70. This soft braking pressure acts like a counter pressure and causes the pressing device to be softly braked. The height of the soft brake pressure is then determined by adjusting the proportional pressure limiting valve 250.

The buffer valve unit thus makes it possible to optimize the start and stop processes of the press machine, thus ensuring a high degree of safety for the entire production machine. In addition, the drive noise level of the press machine is reduced, which reduces the mechanical load on the press machine, which results in a longer life of the manufacturing machine.

FIG. 1b shows a valve device corresponding to FIG. 1a with a buffer valve unit 20 and a corresponding safety valve unit 10 which are designed differently from FIG. 1a. Thus, with regard to the features and one or more functions of the safety valve unit, reference may be made to the full extent to the description for FIG.

In the embodiment shown in FIG. 1 b, there is additionally provided a root valve 300 formed of a seat valve structure 310, which root valve is connected in parallel with a pressure limiting valve 250. The root valve 300 is driven via the pilot valve 330. On the basis of the seat valve design, i.e. as with the root valves 140 and 150, high flow values and shorter switching times during braking are possible, especially in the critical areas of the press. The root valve 300 has a spring force of 32 when it is not energized.
It is opened by 0 and is in the basic position, and even in the absence of current, it is in the opened position. The opened position is monitored by the switching position sensor device 301. The open position of the root valve 300 also switches very quickly and is very effective emergency off or high speed braking (piston 80) of the press machine.
Through)). This is because, if there is fluid pressure in the working conduit 130, it can be disrupted via the conduit 223, the tank conduit 220 and especially the conduit line 222 with little delay.

Another advantage of the seat valve construction of the root valve 300 is that the damping valve unit 20 can be monitored directly via the valve seat 310 of the root valve 300, which ensures a very high degree of safety with respect to damping characteristics. There is something to do.

FIG. 2 illustrates the functional sequence of the valve device shown in FIGS. 1a and 1b, using the following time course of the variables listed from top to bottom in the order of FIG. 2: The voltage transition 50 in the electromagnets 235, 245 of the pilot valves 230, 240
0; -current profile 510 in the electromagnet 265 of the proportional pressure reducing valve 260; -current profile 520 in the electromagnet 255 of the proportional pressure limiting valve 250; -pressure profile 530 in the clutch / brake combination; and-rotation in the drive shaft of the press machine. Number transition 540.

By driving the pilot valves 230 and 240, these pilot valves move to the cross position, and the root valve 90 is opened. Because at that time the control chamber 1
This is because 15 is discharged via the tank conduit 220. At the same time, the two root valves 140 and 150 close. Because their control chambers 162, 17
5 is supplied with pump pressure, which moves the pistons 155, 165 to the seat position.

Therefore, after a certain lead time (fluidic transient time), the load (here clutch /
The pressure in the brake combination) increases. After the pressure is built up there, the rotational speed of the drive shaft of the pressing device also rises to the nominal rotational speed. By operating the proportional pressure reducing valve 260, of course, the pressure rise is dampened, thus resulting in a slow rising rpm curve as shown overall.

After the root valves 90, 140, 150 have moved to the basic position again by the new switching of the pilot valves 230, 240, the short-time proportional pressure reducing valve 250 is driven,
This allows the pressure present in the load 80 to be reinforced and collapsed via the tank conduit 220. In that case, after a time delay, the rotational speed also drops back to its original value.

The previously described switching delay for the root valves 140, 150 in opening the root valve 90 prevents a fluid short circuit between point A of the root valve 90 and point B of the root valve 140, 150. . Furthermore, by means of this, the starting of the pressing device is also possible without a soft clutch. Furthermore, the crossover in time and thus the soft clutch pressure is externally adjusted.

It should be noted that the valve device according to the invention can be used not only effectively in mechanical pressing devices, but can also be used everywhere where large masses are moved by fluid-actuated clutches and / or brakes. it can.

[Brief description of drawings]

FIG. 1a shows a first example of a fluid pressure valve device including a safety valve unit and a buffer valve unit.

Figure 1b   2 shows a valve device corresponding to FIG. 1a, in which the buffer valve unit differs from that in FIG.

FIG. 2 is a functional sequence diagram illustrating a working method of the valve device shown in FIGS. 1a and 1b.

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] October 22, 2001 (2001.10.22)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Contents of correction]

[Claims]

─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3H082 AA18 BB08 CC02 DA11 DA32                       DA46 DC04 EE03                 3H089 AA27 BB28 CC01 DA02 DB03                       DB05 DB46 DB48 DB73 DC02                       GG02 HH16 JJ03                 4E089 BA02 CA03 CA04

Claims (20)

[Claims] 1. A fluid pressure source (1) by means of at least one pressure connection (30).
40) and a fluid load (80) by at least one working connection (70),
And a tank (6) with fluid by at least one tank connection end (50).
0) and having at least two working valves (90, 140), said working valves being operable by at least one electrically actuatable control valve (230). Safety valve unit for driving a load (80), characterized in that at least two working valves (90, 140) are formed as seat valves (110, 170). 2. At least two working valves (90, 140) are driven in opposite directions, in which case the first working valve (90) in the open state has a pressure connection (
30) at least with the working connection (70), and at least the second working valve (140) in the open state has the working connection (70).
The safety valve unit according to claim 1, characterized in that 70) is connected to the tank connection end (50). 3. Safety valve device according to claim 2, characterized in that at least the second working valve (140) is opened without energization by a spring force (180). 4. At least two working valves (90, 140) are designed as 2 / 2-root valves and at least one control valve (230) is designed as a 4 / 2-root valve, in which case At least one control valve (230) reverses the piston connection of at least two working valves (90, 140) to the pressure connection end (3).
0) and the tank connecting end (50) are connected to the safety valve device according to claim 2 or 3. 5. The at least two working valves (90, 140) are operable by the same at least one control valve (230).
The safety valve unit according to any one of 1 to 4. 6. At least two second working valves (140) are provided as two parallel-connected 2 / 2-route valves (1), according to claim 1. The safety valve unit according to the item. 7. The first working valve (90) is at least a second working valve (140).
7.) The safety valve unit according to any one of claims 1 to 6, wherein the safety valve unit is driven with a time delay with respect to. 8. The at least two working valves (90, 140) each have an inductive switching position sensor (95, 145).
The safety valve unit according to any one of 1 to 7. 9. A buffer valve unit using the safety valve unit according to any one of claims 1 to 8, wherein a pressure reducing valve (90) is provided at a front stage on the pressure connection end side of the first working valve (90). 260) is connected to the buffer valve unit. 10. The buffer valve unit according to claim 9, wherein a pressure limiting valve (250) is connected to at least a front stage of the second working valve (140) on the tank connection end side. 11. Buffer valve unit according to claim 10, characterized in that the pressure limiting valve (250) is closed without energization by spring force. 12. At least a second working valve (140) and a pressure limiting valve (250).
12. A buffer valve unit according to claim 10 or 11, characterized in that a fluid spring energy storage device (290) is arranged between it and. 13. A pressure limiting valve (270) is arranged between the working connection (70) and the tank connection (50), as claimed in any one of claims 9 to 12. The buffer valve unit described. 14. A buffer valve unit, in particular using a safety valve unit according to any one of claims 1 to 9, which is arranged as at least one tank connection end and is formed as a seat valve (310). A buffer valve unit characterized by an open root valve (300). 15. A pressure limiting valve (250) is connected to a front stage of at least the second working valve (140) on the tank connecting end side, and at least one root valve (300) is a pressure limiting valve (300). 250) Buffer valve unit according to claim 14, characterized in that it is connected in parallel to 250). 16. Buffer valve unit according to claim 14 or 15, characterized in that at least one root valve (300) is actuatable by at least one control valve (330). 17. At least one root valve (300) has a spring force (320).
The buffer valve unit according to any one of claims 14 to 16, wherein the buffer valve unit is opened by means of (1) without energization. 18. Buffer valve unit according to claim 14, characterized in that the root valve has an inductive switching position sensor (301). 19. A safety valve unit according to any one of claims 1 to 8 and a buffer valve unit according to any one of claims 9 to 13 or claims 14 to 18. , Valve device. 20. The safety valve unit according to any one of claims 1 to 8 and / or the buffer valve unit according to any one of claims 9 to 13 or any one of claims 14 to 18. With a press safety valve.