EP3384164B1 - Monitoring device for tool turret - Google Patents

Description

The invention relates to a monitoring device for determining at least one position of a displacement piston with the features in the preamble of claim 1.

In the prior art, displacement pistons, which can be moved under pressure and controlled by a pressurized fluid control device, are used in tool turrets to carry out switching operations. This can involve locking the rotational movement of the turret relative to the housing or the actuation of a sliding clutch between a motor drive device and a machining tool to be driven. The document DE 41 16 774 C1 shows an example of a tool turret in which, to lock the rotational movement of the turret relative to the housing, coaxial Hirth toothings are provided on this and on the turret head, with which a toothing on a displacement piston which is pressure-operated comes into engagement for locking purposes. The document DE 10 2009 042 772 A1 discloses a drive device in a tool turret, in which, for switching a sliding clutch, the drive shaft of the clutch forms a displacement piston which is hydraulically movable for the switching operations of the clutch.

For the operational control of the tool turrets in question, checking the switching operations carried out by means of the sliding pistons is essential. The usual procedure for this is that an inductive proximity switch detects the piston position in an end position. Since proximity switches suitable for this require a lot of installation space and are also expensive, so far only the detection of an end position of the piston has been possible.

The US 5,778,753 describes a monitoring device for determining at least one position of a displacement piston with the features in the preamble of claim 1 with a housing, a pressurized fluid control device, a pressure detection device and the displacement piston, which is guided in the housing in a longitudinally movable manner and delimits at least one fluid space with a variable volume in the housing , which can be connected to the pressure fluid control device via a pressure supply connection, wherein a volume flow control device is provided, and wherein between the pressure fluid control device and a measuring connection of the associated fluid space of the displacement piston, the volume flow control device and, following this in the direction of the measuring connection, the Pressure detection device are connected, which emits a measurement signal at least when the displacement piston has reached a predeterminable end position in the housing, the pressure detection device being formed from a pressure switch which emits the measurement signal as soon as the displacement piston closes the measurement connection in the associated fluid space, and wherein the volume flow -Control device is formed from at least one aperture.

The DE 1 576 070 A1 , the DE 10 2012 019 863 A1 and the WO 2005/ 024245 A1 describe further monitoring devices.

Based on this prior art, the object of the invention is to provide a monitoring device of the type mentioned at the beginning To provide which, with a compact design, enables the monitoring of at least one piston end position in a simple manner.

According to the invention, this object is achieved by a monitoring device which has the features of patent claim 1 in its entirety.

According to the characterizing part of claim 1, an essential special feature of the invention is that the volume flow control device is formed from the orifice and a pressure reducing valve connected downstream in the direction of the measuring connection.

It is further provided that between the pressure fluid control device and a measuring port of the assignable fluid space of the displacement piston, a volume flow control device and, following this in the direction of the measuring port, a pressure detection device are connected, which emits a measurement signal at least when the displacement piston has a predeterminable end position reached in the housing. Fluidic detection, in which the already existing pressurized fluid control device is part of the monitoring device and proximity switches are eliminated, simplifies the construction effort and reduces the space requirement. In addition, with measuring connections with associated pressure detection devices preferably provided on the spaces on both sides of the piston, both opposite end positions of the piston can be detected.

The solution according to the invention is preferably used in tool turrets or tool disks, as are usually used in machine tools for machining. Further applications include milling spindles, rotary tables and the like, wherever monitoring of fluidically controllable actuating cylinders is required, especially with regard to their end position.

The volume flow control device is formed from at least one orifice with a pressure reducing valve connected downstream in the direction of the measuring port, and the pressure detection device consists of a pressure switch that emits a measuring signal as soon as the displacement piston closes the measuring port in the assignable fluid space. In this arrangement, the volume flow control device is designed for a very low volume flow, which is supplied by the pressure fluid control device to the respective measuring port, which is closed by the piston at a relevant end position, which leads to a pressure increase in the relevant measuring line leading to the measuring port , through which the associated pressure switch switches.

A spring-loaded check valve can advantageously be connected between the pressure detection device and the assignable measuring connection, which opens in the direction of the measuring connection and only has a low closing pressure, preferably less than 1 bar, preferably 0.5 bar. As a result, the measuring line is secured against the actuation pressure prevailing in the fluid space and moving the piston away from the measuring connection.

The arrangement can advantageously be such that the fluid space with the measuring connection is connected to a pressure supply connection of the pressure fluid control device, via which the pressure fluid flows to a pressure sink or tank as soon as the displacement piston moves in the direction of the measuring connection.

In particularly advantageous embodiments, the displacement piston delimits two fluid spaces in the housing, each of which adjoins one side of the piston and which are both connected to a pressure detection device. The displacement piston can thereby be actuated hydraulically by pressure supply connections of the pressure fluid control device for its displacement movements in both directions.

Alternatively, one fluid space can be controlled hydraulically and the other fluid space of the displacement piston can be controlled pneumatically, preferably supported by an energy storage device such as a compression spring.

In both of the aforementioned cases, the respective pressure fluid control device can have at least one control valve between at least one pressure supply source and the fluid space of the displacement piston that can be acted upon hydraulically.

Depending on whether it is a purely hydraulic or a hydraulic/pneumatically operating embodiment, pressure supply sources are provided which feed a pneumatic medium and/or hydraulic medium into the supply circuit for the displacement piston.

The displacement piston, the positions of which can be determined by means of the monitoring device, can be part of a Hirth toothing of the locking device between the tool turret and the housing or can be part of a tool coupling, via which a motorized tool drive can be coupled to a machining tool on a tool turret.

Fig. 1

in Symboldarstellung die Hydraulikschaltung einer ersten Ausführungsform der erfindungsgemäßen Überwachungseinrichtung;

Fig. 2

in Symboldarstellung die hydraulisch/pneumatische Schaltung einer zweiten Ausführungsform der erfindungsgemäßen Überwachungseinrichtung;

Fig. 3

einen schematisch vereinfacht und abgebrochen gezeichneten Teillängsschnitt, in dem von einem Werkzeugrevolver lediglich der Teilbereich dargestellt ist, der einer Verriegelungseinrichtung zwischen Gehäuse und Revolverkopf benachbart und mit einer Überwachungseinrichtung gemäß der ersten Ausführungsform der Erfindung versehen ist;

Fig. 4

einen vergrößert gezeichneten Teilausschnitt aus Fig. 3;

Fig. 5

eine der Fig. 3 entsprechende Darstellung mit demgegenüber verdrehter Schnittebene;

Fig. 6

einen vergrößert gezeichneten Teilausschnitt aus Fig. 5;

Fig. 7 und 8

Teillängsschnitte des der Verriegelungseinrichtung benachbarten Bereichs des Revolverkopfs mit jeweils verdrehter Schnittebene; und

Fig. 9

einen schematisch vereinfacht und abgebrochen gezeichneten Längsschnitt, in dem von einem Werkzeugrevolver die motorische Antriebseinrichtung für einen Werkzeugantrieb mit einer durch einen Verschiebekolben betätigbaren Schiebekupplung dargestellt ist, die mit einer Überwachungseinrichtung gemäß der zweiten Ausführungsform der Erfindung versehen ist.

The invention is explained in detail below using exemplary embodiments shown in the drawing. Show it:

Fig. 1

a symbolic representation of the hydraulic circuit of a first embodiment of the monitoring device according to the invention;

Fig. 2

a symbolic representation of the hydraulic/pneumatic circuit of a second embodiment of the monitoring device according to the invention;

Fig. 3

a schematically simplified and aborted partial longitudinal section, in which only the portion of a tool turret is shown which is adjacent to a locking device between the housing and the turret head and is provided with a monitoring device according to the first embodiment of the invention;

Fig. 4

an enlarged partial section Fig. 3 ;

Fig. 5

one of the Fig. 3 corresponding representation with a twisted cutting plane;

Fig. 6

an enlarged partial section Fig. 5 ;

7 and 8

Partial longitudinal sections of the area of the turret head adjacent to the locking device, each with a rotated cutting plane; and

Fig. 9

a schematically simplified and broken longitudinal section, in which the motor drive device for a tool drive of a tool turret is shown with a sliding clutch which can be actuated by a displacement piston and which is provided with a monitoring device according to the second embodiment of the invention.

The. Fig. 1 shows the fluid circuit for a first embodiment of the monitoring device according to the invention, with a respective displacement piston 1 with its two piston sides delimiting a fluid space 3 and 5 in the housing 7 of a tool turret, which is closed except for inflows and outflows. By supplying hydraulic pressure fluid into the fluid space 3, the piston 1 is moved from the intermediate position shown to the right an end position can be moved, which, if the piston 1 forms part of a locking device, corresponds to the locking state between the turret and the housing. By building up hydraulic pressure in the fluid space 5, the piston 1 can be moved to the left into an end position, which in this case corresponds to the unlocking state. For the supply of pressurized fluid, a supply connection 9 is provided on the fluid space 3 and a supply connection 11 on the fluid space 5, each of which is connected to a pressurized fluid control device 13. In addition, a measuring connection 17 is provided on the fluid space 3 and a measuring connection 15 is provided on the fluid space 5. These measuring ports 15, 17 can each be closed by the piston 1, preferably in a sealing manner, when it reaches the corresponding end position, ie the piston 1 closes the measuring port 15 when it reaches the locking position and closes the measuring port 17 when it reaches the unlocking position.

The pressurized fluid control device 13 has an electrically operated 4/2-way valve 19 with useful connections A and B, a pressure connection P and a tank connection T as a pressure sink. The useful connection A is connected to the supply connection 9 of the fluid space 3 via a supply line 21, and the useful connection B is connected to the supply connection 11 on the fluid space 5 via a supply line 23. A pressure supply unit is connected to the pressure connection P of the directional control valve 19, which has an electric motor-driven hydraulic pump 25 in the manner usual with such supply units, which provides the working pressure for a pressure line 27 leading to the pressure connection P of the directional control valve 19. To stabilize the pressure, a hydropneumatic pressure accumulator 29 is connected to its fluid side, the gas side of which is preloaded with 40 bar, for example, in accordance with the working pressure intended for the pressure line 27. In the line section leading from the hydraulic pump 25 to the pressure line 27 there is a filter 31 which adjoins the pressure side of the hydraulic pump 25, a check valve 27 opening in the direction of the pressure line 27 and a pressure control valve 35 which secures the pressure line 27 against the tank and is set to a pressure of, for example, 50 bar. There is also a manually operated shut-off valve 37 and a pressure gauge 39 in the pressure line 27, which allows the system to be emptied.

At the in Fig. 1 In the embodiment shown, in which purely hydraulic actuation is provided for the displacement piston 1, both fluid spaces 3 and 5 are connected as pressure spaces via their supply connections 9 and 11 and the associated supply lines 21 and 23 to the useful connections A and B of the directional control valve 19. In addition, both measuring ports 15 and 17 are each connected to the pressure fluid control device 13 via a measuring line in such a way that the measuring port 15 is connected to the useful port A via a measuring line 41 and the measuring port 17 is connected to the useful port B of the directional control valve 19 via a measuring line 43 are. In each of the measuring lines 41 and 43, a volume flow control device 45, a pressure switch 47 and a check valve 49 are arranged in succession in the direction of the respective measuring connection 15 or 17.

The volume flow control devices 45 are each formed by a diaphragm 50 and a pressure reducing valve 51 connected downstream of it in the direction of the respective measuring connection 15 or 17. The check valve 49, which is connected directly to the respective measuring connection 15 and 17 in the course of the measuring lines 41 and 43 and opens in the direction of the measuring connection 15, 17, is set to a low closing pressure of, for example, 0.5 bar. The volume flow control devices 45 are designed in such a way that only an extremely small volume flow flows to the associated measuring connection 15, 17 in the measuring lines 41 and 43 when the check valve 49 is open. There is no significant difference here either Pressure builds up on the side of the measuring ports 15, 17, since when the piston 1 is moved, fluid can flow out directly from the respective chamber 3, 5 via the lines 9 and 11.

With this arrangement, the functioning of the position monitoring is as follows. The Fig. 1 shows a state in which the directional control valve 19 connects the pressure port P with the useful port B, so that the working pressure supplies the fluid space 5 with working pressure via the supply line 23 and the supply port 11. When the check valve 49 is locked, the displacement piston 1 moves towards the unlocking position (in Fig. 1 to the left), whereby the fluid volume located in the fluid space 3 is displaced from the supply connection 9 via the supply line 21 to the useful connection A of the directional control valve 19 and flows out from there via the tank connection T, which serves as a pressure sink and is connected to the tank via a check valve 52 . Since this is set to a very low opening pressure and the fluid space 3 is therefore essentially pressureless, the check valve 49 connected to the measuring connection 17 is open. However, as soon as the piston 1 reaches its locking end position, it closes the measuring connection 17, which leads to a pressure increase in the measuring line 43, through which the pressure switch 47 switches and delivers a position signal for the locking end position.

The locking end position is detected in a corresponding manner when the directional control valve 19 is switched from the in Fig. 1 switching state shown, whereby the in Fig. 1 The displacement movement of the piston 1 to the right closes the measuring connection 15 and the increase in pressure in the measuring line 41 causes the switching process of the pressure switch 47, so that the locking end position is signaled.

At the in Fig. 2 In the embodiment shown, only the fluid space 5 is provided as a pressure space for pressure actuation of the piston 1, while the piston movement in Fig. 2 to the right towards the final position in this embodiment as the engagement end position of a sliding clutch, see. Fig. 9 , is provided, is effected by a compression spring 53. The housing 7 leading the displacement piston 1 is open on the piston side on which the compression spring 53 engages, but, as in the first embodiment, has a measuring connection 17 which can be closed by the displacement piston 1 in the disengagement end position. The pressure fluid control device 13 is designed as in the first embodiment, as is the measuring line 41, which leads from the useful connection A of the directional control valve 19 to the measuring connection 15 on the fluid space 5, the supply connection 11 of which, as in the first embodiment, is connected via the supply line 23 to the Useful connection B of the directional control valve 19 is connected.

The difference to the first embodiment is that for pneumatic detection of the uncoupling end position, in which the piston 1 closes the measuring connection 17, a pneumatic supply 56 is provided, which is connected to the measuring line 43 leading to the measuring connection 17. This pneumatic supply has an electrically operated 2/2-way valve 54, via which the measuring line 43 can be connected to an output line 55 of a source, not shown, for a pneumatic pressure in the range of 2 to 6 bar. As in the first embodiment, the measuring line 43 has a diaphragm 50 and, downstream of this in the direction of the measuring connection 17, a pressure switch 47. The other measuring line 41 associated with the fluid space 5 is designed as in the first embodiment. As a result, the detection of the engagement end position takes place in the same way as in the first embodiment, while the disengagement end position is signaled by switching the pressure switch 47 due to the increase in the pneumatic pressure in the measuring line 43 caused when the measuring connection 17 is closed.

The Figures 3 to 8 illustrate the use of the first embodiment of the monitoring device according to the invention for detecting the switching states of the locking device by means of the turret 58 of a tool turret can be locked in selected rotational positions relative to the housing 7. The locking device of the tool turret has, in a known manner, on the turret 58 a toothed ring 59 which is concentric to the axis of rotation of the turret 58 and in the form of a radial toothing, a so-called Hirth toothing. A second toothed ring 60, also with Hirth toothing, is formed on the housing 7, concentric and aligned with this. For the locking engagement with these toothed rims 59, 60, the displacement piston 1 is provided as a locking part, which also has a toothed rim 62 in the form of a Hirth toothing, which comes into engagement with the toothed rims 59, 60 in the locking position. In the Figures 3 to 7 the displacement piston 1 is shown in its unlocking end position lifted from the toothed rims 59, 60. For its displacement movements, the piston 1 is guided in an annular body 63 of the housing 7 and is sealed from it by sealing rings 64 and 65, so that the fluid spaces 3 and 5 which enable the pressure actuation are formed on both axially opposite sides of the piston 1. The Figures 3 and 4 show a channel 66 running in the housing 7, which forms the supply line 21 for the fluid supply to the supply connection 9 of the fluid space 3. The Figures 5 and 6 show a channel 67 in the housing 7, which forms the supply line 23 for the fluid supply to the supply connection 11 of the fluid space 5.

In the Figures 3 to 8 , in which the tool turret is only partially shown, the tool disk, which is provided with a tool holder in the usual way, is not shown. To accommodate this tool disk, the turret 58 has a radially projecting annular flange 69, which forms a contact surface 70 on which the tool disk, not shown, is attached. The rotary bearing for the turret 58 has a radial bearing 72 on a guide part 71 which projects radially from the housing 7 and is overlapped by the turret 58.

The external pressure fluid control device 13, to which the channels 66 and 67 forming the supply lines 21 and 23 lead, is shown in the partial representations Figures 3 to 8 not shown, as are the volume flow control devices 45, which are connected together with the associated pressure switch 47 and check valve 49 to the measuring ports 15 and 17 of the fluid spaces 5 and 3, respectively. These measuring connections 15 and 17 are in the Figures 7 and 8 shown. From this shows the Fig. 7 the measuring connection 17 located on the fluid space 3, which is closed when the piston 1 is in the unlocking end position shown in this figure. In this figure, a measuring channel is designated 73, which leads from the measuring connection 17 to the check valve 49 of the associated measuring line 43. The Fig. 8 , which shows the piston 1 in the locking end position, shows a measuring channel 74 which leads from the measuring connection 15 of the fluid space 5 to the check valve 49 of the associated measuring line 41. The pressure-operated displacement of the piston 1 into one or the other end position, in which the measuring port 9 or 11 is closed, thereby generates the pressure signal which switches the associated pressure switch 47 and thereby signals one or the other end position.

The Fig. 9 clarifies the use of the second embodiment ( Fig. 2 ) the monitoring device according to the invention for detecting the engagement state and the disengagement state of a sliding clutch, via which an electric motor drive can be coupled to a machining tool in a tool turret. The sliding clutch has an axially displaceable clutch hub 76, which is in Fig. 9 is shown in its disengaged position, into which it is pushed back against the force of the compression spring 53 acting on it. This displacement force is caused by pressure actuation of the displacement piston 1, which is guided in an annular body 79 forming a cylinder liner. The piston 1 is sealed relative to the annular body 79 and the coupling hub 76 by means of seals 80 and 81, so that the fluid space 5 has a pressure space on the outside of the piston forms the piston 1 in. by supplying pressure via the supply connection 11 Fig. 9 moved downwards and the clutch hub 76 together with its roller bearing 83, which is gripped by the piston 1, is moved downwards into the disengagement position.

To detect this disengagement position, the piston 1 closes the measuring connection 17 located on its underside. When switching to the engagement state by interrupting the pressure supply to the fluid space 5 via its supply connection 11, the compression spring 53 moves the coupling hub 76 with the piston 1 in Fig. 9 upwards, so that the piston 1 closes the measuring port 15 with a step 87 delimiting the fluid space 5 and thereby generates the pressure signal through which the pressure switch 47 closes and signals the engagement state.

Claims (8)

1. Monitoring device for determining at least one position of a displacement piston (1), having a housing (7), a pressurised fluid control device (13), a pressure determining device (47) and the displacement piston (1), which is guided in a longitudinally displaceable manner in the housing (7) and delimits at least one fluid chamber (3, 5) with a variable volume in the housing (7), said chamber being able to be connected via a pressure supply port (9, 11) to the pressurised fluid control device (13),

   wherein a volume flow control device (45) is provided,

   wherein the volume flow control device (45) and, downstream of the latter in the direction of the measurement port (15, 17), the pressure determining device (47) are connected between the pressurised fluid control device (13) and a measurement port (15, 17) of the assigned fluid chamber (5, 3) of the displacement piston (1), said pressure determining device emitting a measuring signal at least when the displacement piston (1) has reached a predefinable end position in the housing (7),

   wherein the pressure determining device (47) is formed by a pressure switch (47) which emits a measuring signal as soon as the displacement piston (1) closes the measurement port (15, 17) in the assigned fluid chamber (3, 5), and

   wherein the volume flow control device (45) is formed by at least one aperture (50),

   characterised in that

   the volume flow control device (45) is formed by the aperture (50) and a pressure-reducing valve (51) connected downstream in the direction of the measurement port (15, 17).
2. Monitoring device according to claim 1, characterised in that a spring-loaded check valve (49) is connected between the pressure determining device (47) and the assigned measurement port (15, 17), said valve opening in the direction of the measurement port (15, 17) and only having a low closing pressure, preferably less than 1 bar, more preferably 0.5 bar.
3. Monitoring device according to either claim 1 or claim 2, characterised in that the fluid chamber (3, 5), with the measurement port (15, 17), is connected to a pressure supply port (A, B) of the pressurised fluid control device (13), by means of which the pressurised fluid flows out to a pressure sink (T) as soon as the displacement piston (1) moves in the direction of the measurement port (15, 17).
4. Monitoring device according to any of the preceding claims, characterised in that the displacement piston (1) in the housing (7) delimits two fluid chambers (3, 5), both of which are connected to a pressure determining device (47).
5. Monitoring device according to any of the preceding claims, characterised in that one fluid chamber (5) in each case can be actuated by hydraulic means and the other fluid chamber (3) of the displacement piston (1) can be actuated by pneumatic means, preferably supported by an energy accumulator such as a compression spring (53).
6. Monitoring device according to any of the preceding claims, characterised in that the respective pressurised fluid control device (13) comprises at least one control valve (19) between at least one pressure supply source (27) of the pressurised fluid control device (13) and the respective hydraulically actuatable fluid chamber (3, 5) of the displacement piston (1).
7. Monitoring device according to any of the preceding claims, characterised in that respective pressure supply sources (56; 27) are provided, which supply a pneumatic medium and/or hydraulic medium to the supply circuit for the displacement piston (1).
8. Monitoring device according to any of the preceding claims, characterised in that the displacement piston (1) is part of a Hirth toothed system (62) or a tool coupling (76) in the field of application of tool turrets.

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