EP0775831B1 - Clamping device - Google Patents

Abstract

The module (M) has a pressure reduction valve (D) connected to a pressure source and contg. a control piston and clamping-pressure monitoring pressure switch (5). A directional control valve (W) is connected to the pressure switch via a supply line and via load lines to the clamping device. A load pressure tapping in the control valve is connected via a control line to a control input of the pressure reduction valve. The control valve (W) can be set into at least one creep path setting and one rapid return path setting for the clamping device control position. The control valve contains a creep path choke (K) upstream of the load pressure tapping (Z), which chokes the flow between the supply line (P') and load line (A) in the creep path switch setting. The flow is unchoked in the rapid return path setting.

Description

The invention relates to a clamping module in the preamble of Claim 1 specified Art.

In clamping modules known from DE-A-42 37 901 and DE-U-94 13 273 the directional control valve is a black and white valve that is suitable for both adjustment directions each have a through opening releases predetermined size. This results in everyone Direction of movement a certain speed of movement Tensioner. Because the jig is not too fast the clamping position may be reached, the adjustment takes place, relatively slow, especially at low clamping pressure. at large strokes take a lot of time. Because with modern Machine tools the clamping device, e.g., a Tailstock quill or tailstock after every work cycle first far into a starting position and then back into the Clamping position should be used for clamping uncritical stroke can be adjusted in rapid traverse, and should approximate the tension position in the creeper and run under pressure. This is the case with the known clamping modules not possible. In practice, therefore, are sometimes second directional valve connected to the pressure source is provided and between the second directional valve and the consumer lines adjustable throttle valves provided to the Clamping device without influencing the clamping module in each Travel direction in rapid traverse.

A clamping module known from DE-AS 23 10 193 is missing Rapid traverse and a creeper.

In a known from DE-A1-42 34 036, by means of the load pressure regulating Valve arrangement for a hydraulic consumer Each spool directional control valve works on a mobile working device together with a pressure compensator, the one forms load-dependent inlet regulator. For a rapid traverse function is between the load pressure line and the pump or. Return line provided a further directional valve. Further the load pressure line is a check valve in normal operation from the additional directional control valve or from the return Cut. The load pressure line is used for the rapid traverse function acted on by the pump pressure, so that the pressure compensator of the inlet regulator opens at the front. It is typically one for a mobile crane usual valve arrangement, which is suitable for a machine tool clamping device is not suitable.

The invention has for its object a clamping module to create the type mentioned, the structurally simple Building at least one rapid traverse and one creeper.

The task is with the features of the claim 1 solved.

The creeper throttle limits in the crawler gear switch position the directional control valve the speed of the clamping device, which slowly moves into the clamping position. The Pressure reducing valve monitors compliance with its pressure switch of the clamping pressure. Only in the rapid traverse switch position is a rapid adjustment via the unthrottled flow path the tensioner controlled. The structural Additional effort for the creeper and rapid traverse is low, because components already provided in the clamping module anyway be used for the additional functions. Also in The pressure reducing valve can move rapidly with the pressure switch Monitor pressure. The for the important function of the pressure switch of the pressure reducing valve required consumer pressure tapping is upstream of the consumer pressure tap arranged creeper throttle is not affected. A large stroke can be traversed quickly in rapid.

As with the clamping pressure set low on the pressure reducing valve the pressure reducing valve could undesirably shut down in rapid traverse, is according to claim 2 in the rapid traverse switching position of the directional valve relieves the control pressure line to the return, so the pressure switch does not respond.

Inexpensive and reliable is according to claim 3 Switching magnet responsible for the switching position of the directional valve.

According to claim 4, a proportional magnet adjusts depending on the current the directional valve. This can be beneficial if the directional valve in addition to a rapid or crawl gear shift position another rapid traverse and / or crawl gear switch position would be required. It could also be a step solenoid with multiple Switching magnets are used.

According to claim 5, the control is structurally simple in rapid traverse and reached in crawl. In the rapid traverse switch position the pressure medium can be essentially unthrottled flow to the jig. In the creeper gear position the pressure medium in the directional spool has the creeper throttle to happen so that there is a low creeper speed results. The load pressure tap reports the consumer pressure for the pressure switch on the pressure reducing valve.

According to claim 6, the load pressure tapping is structurally simple provided with a switch depending on the stroke of the slide, around the load pressure tapping and thus a work of the Then secure the pressure reducing valve with its pressure switch, when the clamping pressure has to be monitored.

Claim 7 is directed to a structural simplification.

According to claim 8, the actuating movements of the switching magnet transmitted directly and precisely. By means of the attacks and / or change the ram lengths Change speeds for creeper and / or rapid traverse.

According to claim 9, the adjustment speed of the Clamping device at least in the rapid traverse switching position of the Adjust directional valve as required. The adjusting screw sets the end position of the slide with regard to a desired one Passage size fixed, e.g. via the armature of the switching magnet, which for the expediently also as a rapid traverse switching position designed third switching position of the directional valve is provided for the other direction.

Fig. 1

ein Blockschaltbild eines hydraulischen Spannmoduls mit einer schematisch angedeuteten Spannvorrichtung einer Werkzeugmaschine,

Fig. 1A

eine Detailvariante zu Fig. 1,

Fig. 2+3

einen Vertikalschnitt und einen zugehörigen Horizontalschnitt des Spannmoduls gemäß Fig. 1, in der Grundstellung,

Fig. 4+5

das Spannmodul in einem Vertikal- und einem Horizontalschnitt in einer Kriechgang-Schaltstellung,

Fig. 6+7

einen Vertikalteilschnitt und einen zugehörigen Horizontalteilschnitt des Spannmoduls in der Eilgang-Schaltstellung,

Fig. 8+9

einen Vertikalteilschnitt mit zugehörigem Horizontalteilschnitt des Spannmoduls in einer Eilgang-Schaltstellung für die andere Stellrichtung der Spannvorrichtung,

Fig.10+11

einen Vertikalteilschnitt mit zugehörigem Horizontalteilschnitt der Ausführungsvariante des Spannmoduls der Fig. 1A in der Grundstellung, und

Fig. 12

einen vergrößerter Ausschnitt aus Fig. 4.

Embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:

Fig. 1

2 shows a block diagram of a hydraulic clamping module with a schematically indicated clamping device of a machine tool,

Fig. 1A

2 shows a detailed variant of FIG. 1,

Fig. 2 + 3

2 shows a vertical section and an associated horizontal section of the clamping module according to FIG. 1, in the basic position,

Fig. 4 + 5

the clamping module in a vertical and a horizontal section in a creeper switch position,

Fig. 6 + 7

a partial vertical section and an associated horizontal partial section of the clamping module in the rapid traverse switching position,

Fig. 8 + 9

a partial vertical section with the associated horizontal partial section of the clamping module in a rapid traverse switching position for the other setting direction of the clamping device,

Figure 10 + 11

a vertical partial section with associated horizontal partial section of the embodiment of the clamping module of FIG. 1A in the basic position, and

Fig. 12

3 shows an enlarged detail from FIG. 4.

A clamping device S according to FIG. 1, for example for a Tailstock quill of a lathe, is by means of a clamping module M controlled, so that the quill in a rapid traverse 1 from right to left over a predetermined stroke is adjustable and the rest of the stroke up to the final Tension position covered in a crawl gear until the desired clamping pressure and a specific position of the quill are reached. In the opposite direction, the Quill adjusted in rapid traverse over the entire stroke. The Clamping module M is e.g. programmed by a not shown Control device performed.

The clamping module M is connected to a pump line P and to a Return line R connected. The pump line P leads to an adjustable pressure reducing valve D, which with the return line R is connected. From the pressure reducing valve D leads on the output side a supply line P 'to an input 7 a directional control directional control valve W. The return line R is connected to a port 8 of the directional control valve W. in the Pressure reducing valve D is loaded by a control spring 3 Control piston 1 included. A housing 2 of the pressure reducing valve D has a control input 4 and an electrical pressure switch 5 on that to the higher-level control "clamping pressure reached "or" clamping pressure not reached "reports and responsive to control movements of the control piston 1. From the control entrance 4 leads a control pressure line 6 to a connection 9 of the directional control valve W. The directional control valve W is in this version adjustable between four switch positions, namely by means of a magnetic actuation 11, which in the present case Series magnets 11a and 11c connected in series on one side and a switching magnet 11b on the other side. A spool 10 is included in the directional control valve W, which has a basic position "0" in the four switch positions (shown), when the step magnet 11c is excited Creep gear switch position c, when the step magnet is energized 11a a rapid traverse switch position a, and when the Shift solenoid 11b another rapid traverse switching position b for takes the opposite direction. At the directional valve W are on connections 12, 13 consumer lines A, B (one double-acting hydraulic cylinder) to the clamping device S connected.

In the slide 10 of the directional valve W is a consumer pressure tap Z is provided, which is in a crawl gear position c present flow path 15 is the upstream of the consumer pressure tap Z a creeper throttle K contains. The consumer pressure drawn is over a flow path 14 is provided at connection 9 of the directional valve, 1 in the creeper gear shift position c. In the rapid traverse switch position a is in Slider 10 is a substantially unthrottled flow path to the consumer line A, and in the other rapid traverse switch position b a also essentially unthrottled Flow path 15 "to the consumer line B. In the Switch positions a and b is the connection 9 of the directional control valve W relieved to return R.

The directional control valve W and the pressure reducing valve D are shown in FIG. 2 housed a common housing G, such that the Supply line P 'from the control piston 1 of the pressure reducing valve D, which cooperates with the pressure switch 5 and through the Control spring 3 is applied approximately in the center and radially leads a bore 16 in which the slide 10 seals is guided.

The magnet actuator 11 with the three magnets 11a, 11c, 11b is flanged coaxially to the slide 10 on the housing G. The Stepped magnet 11a has one against a stop fixed to the housing 18 movable armature 17 on a plunger 19th directly engages the slide 10. The step magnet 11c has a movable against a fixed stop 35 Anchor 36 on the plunger 37 on the armature 17th acts. The switching magnet 11b has one in the opposite Direction movable against a stop 21 fixed to the housing Anchor 20 on the via a plunger 22 on the slide 10th attacks. The end position of the slide 10 at least in the Switch position a can be selected by means of an adjusting screw 23, the on the armature 20 and the plunger 22 on the slide 10 acts, and a plunger 23a for manual override may contain.

In the slide 10, which is secured against rotation in the bore 16, are about two diametrically opposed pockets in the middle 24 formed, which via internal channels 24 'in the slide 10 are interconnected. Axially on both sides of the pockets 24 are constrictions 25 in the sealing zones 26, 27 spaced apart Slider 10 shaped. In the bore 16 forms on both sides of the Supply line P 'the bore wall sealing zones 28 and 29, which cooperate with the sealing zones 26, 27 of the slide. A consumer recess 30 is provided in the sealing zone 28, to which the consumer line A is connected. In a sealing recess 31 is provided in the sealing zone 29, which is connected to the consumer line B. In the transition area from each pocket 24 to the adjacent sealing zone 26, the creeper throttle K is provided (see FIG. 12).

Interspersed in the horizontal section of FIG. 3 associated with FIG. 2 roughly in the same axial plane as the creeper chokes K the slider 10 is a consumer pressure tapping channel 32, which is connected to an axially spaced transverse channel 33 is, the two-sided openings with one in the housing G provided connection 34 to the control pressure line 6 and an approximately diametrically opposite connection 39 to Interact R return. Only in the creeper gear position c (Fig. 4 and 5) there is the tapped consumer pressure in port 34 while in the switch position a the connection 34 and the control pressure line 6 with the port 39 and the return R are connected. Reached this is because the blind holes 42 and 43 are expanded Openings of the transverse channel 33 axially offset from one another with the mouths of connections 34 and 39 or with one narrower mouth 44 of the connection 39 depending on the respective stroke position of the slide 10 to certain Working together wisely. Another cross channel 45 in the slide 10 connects, the terminal 34 in the switching position a with the Connection 39. The channels 32, 33 and 45 are indicated in Fig. 2. 2 are the consumer lines A and B separated. The control pressure line 6 is with the return line R in connection. No magnet is excited. The clamping device S holds its position.

In the creeper gear position c (Fig. 4 and 5) is the Step magnet 11c excited. Its anchor 36 is at the stop 35. The plunger 37 has the armature 17 and the plunger 19 Slide 10 adjusted to the left until the pressure medium from the Pocket 24 through the creeper throttle K and the flow path 15 in the consumer insertion 30 and in the consumer line A flows. The tensioning device S moves in the creeper, the consumer pressure prevailing in the consumer line A. via the consumer pressure tap Z and Control pressure line 6, the control piston 2 of the pressure reducing valve D acts against the force of the control spring 3, so that the pressure reducing valve D works regulatingly and by means of Pressure switch 5 the clamping pressure set on the control spring 3 supervised. Switch position c is selected when the Clamping device S a residual stroke in the final clamping position has to be carried out in which the set on the pressure reducing valve D. Clamping pressure must be observed.

5 is that in the consumer line A prevailing Pressure through the cross channel 32 to and from the cross channel 33 the port 34 and the control pressure line 6 transmitted. The transverse channel 33 is blocked off from the connection 39. In the creeper gear position c, the armature 17 has the stop 18 clear a remaining stroke.

6 and 7 illustrate the rapid traverse switch position a, in which the step magnet 11a is excited and via which to the Stop 18 driven armature 17 and the plunger 19 the slide 10 has moved so far that from the pocket 24 to the consumer puncture 30 the substantially unrestricted flow path 15 is open. The tensioning device S moves in rapid traverse, the speed of which changes according to the pressure in the Supply line P 'and the size of the cross section of the Flow path 15 aligns.

In Fig. 7, switch position a, the transverse channel 33 is opposite blocked the port 34, the other cross channel 45 directly connected to the port 39 and the return R. is. The pressure reducing valve stops in the supply line P1 essentially maintain the pump pressure of the pump line P, so that a high speed for the jig is possible, which is not after the set clamping pressure directed.

The rapid traverse speed can be adjusted by using the adjusting screw 23 the end position of the slide 10 in Fig. 6 is shifted further to the right (reduce speed).

8 and 9 illustrate the further rapid traverse switch position b, in which the switching magnet 11b is excited and over the armature 20 and the plunger 22 the slide 10 in its right Has moved end position. The pockets 24 are unthrottled Flow paths 15 "to the consumer punctures 31 and open to consumer line B. Over the cross channel 33 is the connection 34 is connected to the connection 39, so that the Pressure reducing valve D has no influence on the rapid traverse speed has and the pressure switch 5 does not respond.

In all switch positions c, a and b is the other Consumer recess 31 or 30 connected to the return R, so that the pressure medium from the other chamber of the cylinder the clamping device S can be pushed out.

1A is the consumer pressure tap also in the second rapid traverse switch position a active. The one prevailing in the consumer line A. Pressure is supplied to the control piston 1 via the control pressure line 6 of the pressure reducing valve D transmitted.

A concrete version of this variant of the M clamping module can be seen from FIGS. 10 and 11. The slider 10 differs differs from the slide previously shown in that the further cross channel 45 omitted and at the upper opening of the transverse channel 33, a second blind bore 41 is provided, the in the rapid traverse switch position a the transverse channel 33 with the Connection 34 to the control pressure line 6 connects while the Cross channel 33 is separated from port 39.

12 is in the transition area from the pocket 24 to Sealing zone 26 in the pocket 24 in a transverse area F a Recess 48 formed in from the outside to the creeper throttle K leads at least one radial bore 46. In the in Fig. 12 indicated creeper gear position c can do that Pressure medium from the pocket 24 only the way through the radial bore Take 46. The slider 10 continues into the rapid traverse switching position a adjusted (see Fig. 6 and 7), then works an edge 47 of pocket 24 with one from an edge of the consumer puncture 30 formed control edge 38 together to the passage for the substantially unthrottled flow connection 15 from the pocket 24 into the puncture 30 to open.

The magnet actuator 11 could be used for more than one creeper gear or / and rapid traverse have a corresponding number of step magnets or a proportional magnet (not shown) that is dependent executes the adjustment strokes from the current supply. For changing the speeds of crawl and rapid traverse it would be conceivable to adjust the stops 18, 35 or 21 form, or the plunger 22, 19 and 37 in length to change or replace with plungers with other lengths. The directional valve W could be in its own, and from Pressure reducing valve D may be arranged in a separate housing.

The pressure reducing valve D could be designed as in the DE-A-42 37 901 or DE-U-94 13 273, hereby emphatically Reference is made.

Claims (9)

1. Hydraulic clamping module (M) for machine-tool clamping devices (S), having a pressure-reducing valve (D) which is connected to a pressure source, contains a regulating piston (1) and has a clamping-pressure-monitoring pressure switch (5), and to which a directional control valve (W) is connected via a supply line (P'), this directional control valve (W) being connected to the return (R) and via consumer lines (A, B) to the clamping device (S), and having a consumer-pressure tap (Z) in the directional control valve (W), this consumer-pressure tap (Z) being connected via a control line (6) to a regulating inlet (4) of the pressure-reducing valve (D), characterized in that the directional control valve (W), for at least one actuating direction of the clamping device (S), can be shifted into at least one creep-motion operating position (c) and at least one rapid-motion operating position (a), in that a creep-motion throttle (K) is provided in the directional control valve (W) upstream of the consumer-pressure tap (Z), in that a flow path (15) throttled by means of the creep-motion throttle (K) is provided in the creep-motion operating position (a) between the supply line (P') and the consumer line (A), and in that an essentially unthrottled flow path (15', 15'') is provided in
2. the rapid-motion operating position (a, b) between the supply line (P') and the consumer line (A, B).
3. Clamping module according to Claim 1, characterized in that a relief connection (39, R) is provided in the directional control valve (W), the control line (6) being relieved to the return (R) via this relief connection (39, R) in the rapid-motion operating position (a, b) of the directional control valve (W).
4. Clamping module according to Claim 1, characterized in that the directional control valve (W), at least for the one actuating direction of the clamping device (S), has a two-stage magnetic actuating means (11) with two magnets (11a, 11c) placed one behind the other in series.
5. Clamping module according to at least one of Claims 1 to 4, characterized in that an axially adjustable spool (10) having at least one central, circumferential pocket (24) is provided in the directional control valve (W) in a housing bore (16), circumferential return constrictions (25) spaced apart on both sides via circumferential sealing zones of the spool (10) being assigned to said pocket (24), in that the supply line (P') is radially connected centrally to the housing bore (16), in that the return (R) is connected to the housing bore (16) such as to be spaced apart axially via bore-wall sealing zones (28, 29) on both sides of the supply line (P'), in that a consumer-line recess (30, 31) is provided in each case in the two bore-wall sealing zones (28, 29), in that the creep-motion throttle (K) is formed at the transition from the pocket (24) to a sealing zone (26) of the spool (10) adjacent to the pocket, and in that a pressure-tapping passage (32) opens into the sealing zone (26) of the spool (10), the orifice of this pressure-tapping passage (32) being located in the same radial plane of the spool (10) as the creep-motion throttle (K).
6. Clamping module according to Claim 5, characterized in that the pressure-tapping passage (32) in the spool (10) is connected to a transverse passage (33) which has openings on both sides in the spool circumference, in that a control-line connection (34) and a return connection (39) are provided in the bore (16) for interacting with both openings of the transverse passage (33), and in that either the two openings of the transverse passage (33) or the two connections (33, 39) are offset relative to one another in the axial direction.
7. Clamping module according to Claim 5, characterized in that the creep-motion throttle (K) is at least one radial bore (46) which leads in the spool (10) to the pocket (24), and in that the consumer-line recess (30) in the bore wall has a control edge (38) interacting with the bore (46) in the creep-motion operating position (c) and with the pocket (24) in the rapid-motion operating position (a).
8. Clamping module according to at least one of Claims 3 to 7, characterized in that the operating magnets (11a, 11c) have armatures (17, 36) which are displaceable towards stops (18, 35) fixed to the housing and of which the armature (17) nearer to the spool (10) has a first plunger (19) acting on the spool (10), whereas the second armature (36) has a plunger (37) acting on the first armature (17), and in that the second armature (36), at its stop (35), can be intercepted in a position in which the first armature (17) is facing its stop (18) with clearance.
9. Clamping module according to at least one of Claims 3 to 8, characterized in that the directional control valve (W), at the magnetic actuating means (11), is provided with a spool-stroke setting device (23) with which at least the end position of the spool (10) in the rapid-motion operating position (a) of the directional control valve (W) can be set.

Images