DE102017118069A1 - Multi-column press with guided ram - Google Patents

Abstract

The invention relates to a press for machining workpieces, which includes a press table (10) and a reciprocating reciprocally movable up-and-down plunger (30). The plunger (30) is guided on a guide body (40) which is connected directly to the press table (10). Preferably, by the guide body (40) of the tipping point of the plunger set at the level of the working plane. The press can also be driven by a combination of toggle levers (60) and an eccentric mechanism (70). Furthermore, it preferably has a parallel fixing ° (50) at the ends of the plunger, through which a counterforce is exerted on the plunger in the nominal force range.

Description

The invention relates to a press for machining workpieces, for example for forming or cutting metal parts.

Presses of the aforementioned type are known in many embodiments. They usually contain a press table, above which a press center is arranged so that a work space is created between the press table and press head. Depending on the size of the entire system, the press head is connected to the press table via a stand ("single-column press"), two column jacks ("double column press"), or more columns ("multi-column press"). Furthermore, it usually carries the suspension for a reciprocally movable in a stroke direction ram. Depending on the work to be performed, an associated lower tool part or upper tool part is arranged on the press table and the plunger, between which the workpiece is in the process and undergoes the desired processing.

A problem with known presses is that due to the prevailing high forces of typically several tens, hundreds or even thousands of tons of movements and vibrations are transmitted to the tools. These lead to deteriorated work results as well as rapid wear or breakage of the tools.

Against this background, it was an object of the present invention to provide a press with a higher quality of the processed products as well as a wider field of application and higher process reliability.

This object is achieved by a press having the features of claim 1, claim 4 and claim 8. Advantageous embodiments are contained in the subclaims.

• - Einen Pressentisch, der typischerweise auf dem Untergrund (Boden) abgestellt bzw. hiermit verbunden ist.
• - Ein Pressenhaupt, welches sich typischerweise vertikal oberhalb des Pressentisches befindet.
• - Eine Mehrzahl von Ständern, welche das Pressenhaupt auf Abstand mit dem Pressentisch verbinden, sodass zwischen Pressenhaupt und Pressentisch ein Arbeitsraum ausgebildet wird. Im Falle einer Mehrständerpresse sind dabei mindestens zwei Ständer vorhanden, welche am Pressentisch angeordnet sind.
• - Einen Stößel, welcher im Arbeitsraum angeordnet und in einer Hubrichtung reziprok beweglich ist, wobei die Hubrichtung in der Regel in Richtung der Verbindungslinie von Pressentisch und Pressenhaupt liegt, also typischerweise in Richtung der Vertikalen. Der Antrieb für die reziproke Bewegung des Stößels befindet sich üblicherweise im Pressenhaupt.

The presses according to the invention can in particular be designed as multistage presses and all have the same basic structure, which contains:

• - A press table, which is typically placed on the ground (floor) or connected to it.
• - A press head, which is typically vertically above the press table.
• - A plurality of uprights, which connect the press head at a distance from the press table, so that between the press main and press table, a working space is formed. In the case of a multistage press, there are at least two stands which are arranged on the press table.
• - A plunger, which is arranged in the working space and reciprocally movable in a stroke direction, wherein the stroke direction is usually in the direction of the line connecting the press table and press main, so typically in the vertical direction. The drive for the reciprocal movement of the plunger is usually located in the press head.

According to a first aspect of the invention, the basic structure of a press described above is further developed such that it has a guide body which is directly connected to the press table and which guides the plunger in at least one direction transverse to the stroke direction (in the stroke direction, the movement of the plunger is exposed be). The guide body is preferably connected exclusively to the press table. The ram tilt in the stroke direction is not controlled by any guidance but is solely dependent on the stability of the press elements lying in the power flow.

During a work process enormous forces act in a press, which leads to strains, bends and vibrations of all components involved.

The press according to the first aspect of the invention has the advantage that can be transmitted by the direct connection of the guide body with the press table no such movements directly from the uprights or the press head on the plunger. Disturbing movements of the plunger, especially in the critical time range of a work process are thus avoided. This benefits both the quality of the products produced and the durability of the tools, since no disturbing movements of the plunger are induced at the decisive moment of forming, cutting or the like (higher process reliability).

As a rule, asymmetric forces are exerted on the plunger by the workpiece during a working process, to which the latter reacts with a tilting movement and / or displacement. In this regard, the coupling between the guide body and the plunger is preferably designed to minimize or direct such tilting movements. In particular, the plunger may be rotatably coupled about a predetermined tilting axis with the guide body via a sliding block. That is, in principle, the plunger remains freely rotatable about a predetermined axis, the "tilting axis", but the position of the axis is fixed (except for its position in the stroke direction). This has the great advantage that the tilting axis is fixed and can not migrate variably over a larger area of the plunger during a decline as in conventional presses.

According to one embodiment of the embodiment described above, the coupling between the guide body and plunger is designed so that the tilting axis is located at the level of the working plane. By definition, the working plane is the region (with respect to the plunger) in which the actual machining of a workpiece takes place, ie the forming, cutting or the like. The position of the working plane is generally determined by a tool to be connected with the plunger upper part. By placing the tilting axis in the working plane, it is achieved that no or at most minimal displacement movements of the plunger can take place on the workpiece at the critical time.

According to a second aspect of the invention, the above-explained basic form of a press is further developed by a parallel fixing, which is attached to transverse to the stroke direction ram ends, wherein the parallel fixing in the nominal force on the ram ends in each case a path-dependent counterforce is exercised.

The ram ends considered in this embodiment are typically those transverse to the stroke direction two ends of the plunger, which have the greatest possible distance from each other. For large presses, this distance can be in the range of several meters, so that correspondingly large tilting movements of the plunger are possible. By definition, the "nominal force range" is the stroke interval of the plunger in which it applies the nominal force prescribed by the design or in which the actual processing steps (forming, cutting, etc.) take place on the workpiece. As a rule, the nominal force range is only a few millimeters. In this area, however, asymmetric forces can act on the ram, because different machining operations take place on the machined workpiece at different positions. Such asymmetries of forces then lead to a tilting movement of the plunger. In order to compensate for this tilting movement, a counter force is exerted on the plunger via the parallel fixing. This counteracts, for example, an anticipatory movement of a plunger end, which encounters less resistance on the workpiece.

The size of the opposing force of the parallel fixing or its force-displacement relationship is usually designed as a function of the design of the press, the tools used, as well as the workpiece to be machined. In a preferred embodiment, the magnitude of the counterforce (relative to a ram end) is selected to be about 20 percent to about 40 percent of the nominal force at the bottom (bottom dead center) of the ram.

For the concrete realization of the parallel fixation there are different execution possibilities. In a preferred variant, the parallel fixing at each plunger end comprises a rod, which slides on the one hand on the plunger end and on the other hand by a hollow spindle or the like, the position of which is adjusted by an adjusting the working process. The adjusting unit is attached to a spring. The spring can optionally be one or more leaf springs (spring package). The spring can be mounted on one or more stands of the press. Additionally or alternatively, the spring may also be mounted on a separate holder in order to be independent of the force-loaded uprights.

According to a further embodiment of the parallel fixing, the profile of the counterforce for each plunger end can be adjusted separately. In this way, asymmetric force effects on the plunger can be preset to counteract, for example, known asymmetric effects of the workpiece.

• - Einen Exzentermechanismus, welcher an am Pressenhaupt angeordnet ist und mindestens einen Exzenter enthält.
• - Mindestens einen Kniehebel, dessen eines Ende am Exzenter und dessen anderes Ende am Stößel angeordnet ist. Vorzugsweise sind zwei oder mehrere derartige, im Wesentlichen gleich ausgebildete Kniehebel am Stößel vorgesehen.

According to a third aspect of the invention, the above-explained basic form of a press is further developed by the following components:

• - An eccentric mechanism, which is arranged on the press main and contains at least one eccentric.
• - At least one toggle lever, one end of which is arranged on the eccentric and the other end on the plunger. Preferably, two or more such, substantially identical toggle lever are provided on the plunger.

In the press according to the third aspect, the effects of a toggle lever and an eccentric mechanism are advantageously combined. In particular, the toggle lever can provide a relatively large and substantially force-free lifting movement of the plunger, while the eccentric mechanism applies the actual high pressing forces (over a short distance). The eccentric mechanism contains suitably a rotatably mounted on an axis not symmetrical to the plunger mounted eccentric, which rotates eccentrically on a rotational movement of the axis and this movement transmits to other components such as a toggle.

In a development of such a press, the eccentric is near the middle between its top dead center and its bottom dead center when the toggle is stretched. When the top dead center is defined by an angular position of the eccentric of 0 ° and the bottom dead center by an angular position of the eccentric of 180 ° is, extends the range "near the center" of about 45 ° to about 135 °. The generation of the pressing force by the eccentric mechanism thus takes place in this angular range. This has the advantage that the bearing loads can be better controlled than with an effect of the eccentric mechanism in the area of bottom dead center. For example, in the drive of the eccentric mechanism, overload protection can be integrated in the transmission (torque control).

In principle, it is possible to let the eccentric and the toggle lever move by different drives (motors). In order to simplify the construction, however, it may be provided that the eccentric and the toggle lever are driven by a common drive axle, so that only a single motor is required. With the help of a suitable transmission mechanism, the movements or phases of toggle lever and eccentric can then be matched to one another in the desired manner.

The explained three different aspects of the invention (press with guide body, press with parallel fixing, press with eccentric mechanism and toggle) can of course be combined with each other in any way, so as to achieve synergy effects in terms of improved product quality, lower tool load and / or lighter construction. Conclusions and explanations, which were made for an embodiment of the invention, therefore apply mutatis mutandis to the others.

• 1 den Pressentisch mit angesetzten Ständern;
• 2 den Pressentisch mit angesetzten Ständern und dem Führungskörper;
• 3 den Pressentisch und den Stößel;
• 4 den Pressentisch und den Stößel mit Gleitstein sowie Kniehebeln;
• 5 die Presse von 4 zusätzlich mit dem Führungskörper;
• 6 die Presse von 5 mit nur einem Kniehebel und zusätzlich mit dem Gestänge zur Bewegung der Kniehebel;
• 7 die Presse von 6 zusätzlich mit dem Exzentermechanismus;
• 8 den Pressentisch, zwei Ständer, den Stößel sowie die Parallelfixierung auf einer Seite mit und auf der anderen Seite ohne Feder;
• 9 die komplette Presse mit Pressenhaupt.

In the following the invention will be explained in more detail by way of example with the aid of the figures. In the figures, a press according to an embodiment of the present invention is shown, for reasons of clarity in each case omitting various components and on the left in a view from a first and right in a view from a second viewing direction. In detail shows

• 1 the press table with attached stands;
• 2 the press table with attached stands and the guide body;
• 3 the press table and the ram;
• 4 the press table and the plunger with sliding block and toggle levers;
• 5 the press of 4 in addition to the guide body;
• 6 the press of 5 with only one knee lever and in addition with the linkage for moving the toggle lever;
• 7 the press of 6 additionally with the eccentric mechanism;
• 8th the press table, two stands, the ram and the parallel fixing on one side with and on the other side without spring;
• 9 the complete press with press head.

In 1 are the basic components of the press according to the invention of the press table 10 as well as in the four corners of the press table vertically upwardly extending stand 20 to see. Since the press has four stands, it is a "Mehrständerpresse". For the view shown on the right, an x, y, z coordinate system is further drawn, to which reference will be made occasionally below.

2 shows the representation of 1 additionally with a guide body 40 , which is directly on the press table 10 is screwed. As will be explained in more detail below, the guide body sets 40 in unit with the sliding block ° 32 (see figure ° 4) the tipping point of the plunger of the press firmly.

3 shows the press table 10 as well as about it in the working space movably arranged plunger 30 , In the state of use of the press are on the press table 10 a tool lower part (not shown) and on the plunger plate 35 of the plunger 30 a tool upper part (not shown) attached, between which it comes to the machining of a workpiece. For example, metal parts can be reshaped or cut with the press.

Furthermore, there is the introduction of force of the connecting rod bearings 34 in the pestle 30 as close as possible to the plunger plate 35 , This results in a central load of the plunger, without lateral forces and vibration damaging the tool.

4 shows the representation of 3 , wherein in addition to the two ends in the x-direction of the plunger 30 one toggle each 60 is arranged. By buckling or stretching the knee lever 60 There is a reciprocal up and down movement of the plunger in the working space.

Each toggle consists of an upper arm 61 who has a knee joint with a lower arm 62 (Connecting rod) is connected. The lower arm is still over a spindle 63 with a delivery gear 64 connected, which pivotally in the connecting rod bearing 34 on the plunger body 31 is stored. The spindle 63 can be turned on or off to adjust the stroke position of the plunger as needed to the distance between the lower arm 62 and the delivery gear 64 to change.

Furthermore, in 4 recognizable that the plunger 30 at one of the workroom opposite side over a pin 33 with a sliding block 32 is rotatably connected. The pin 33 is arranged approximately at the level of the working plane of the plunger, ie the plane in which take place when attached tool, the machining processes on the workpiece.

5 shows how the sliding block 32 in the vertical guide slot of the guide body 40 intervenes. Through the interaction of sliding block 32 and leadership body 40 is forced that the plunger 30 just more about the pin 33 can tilt, which thus defines the tilt axis of the plunger. It is important in this regard that the management body 40 directly on the press table 10 is attached so that it is not subject to the general occurring during the pressing process deformations of the press and thus no corresponding disturbances in the plunger 30 enters.

The guide body 40 is preferably centrally in the middle of the press, screwed next to the work area of the multistage press at table height. He takes over the leadership of the ram 30 completely. For very long rams (over 5000 mm in length), additional guides can optionally be provided. They are preferably effective only in the y-direction, not in the x-direction.

The ram tipping point is the neutral point around which the ram 30 in the free power game between the two connecting rods or toggle levers 60 tilts. This theoretical point can in conventional presses during a decline of the ram quite a lot back and forth. Usually, the tilting point is about one meter above the working plane of the tool / plunger. Due to the large distance from the working plane, a large offset from the upper part of the tool to the lower part of the tool is created when the tappet is tilted. This leads to sudden wear on the tool at sudden load changes.

The press described here, however, has a predetermined, exact tilting point on the pin 33 at working height of the tool. As a result, the lower tool part experiences no deflection relative to the upper part. The ram tilting, as occurs with differently loaded connecting rods, is associated with the illustrated press solely the stability of the force-transmitting elements and the ram parallel fixing (see below), and is compensated by them.

A tipping point bearing is for the predetermined tipping point in the sliding block 32 arranged, which also takes over the vertical ram guide in the x direction. By this type of leadership (separate from the influence of Ständer) is a new, very advantageous and effective design of the press stand only possible.

In 6 is the movement drive of the toggle lever 60 recognizable. This drive includes a gear 66 which is driven and thereby an axle 65 set in rotation. At the ends of this axis 65 arranged cams engage over a tie rod in the region of the knee joint of the knee lever 60 to oscillate between a kinked and a stretched position to move back and forth.

In 7 is in addition to the representation of 6 the eccentric mechanism 70 recognizable. This comprises a driven by a motor (not shown) axis of rotation 71 on which a complete drive 72 and a gear 73 are in engagement with the gear 66 the toggle lever drive stands. The rotation of the shaft 71 is thus transferred to the toggle drive. By choosing the gears 66 and 73 The synchronization behavior and the phase relationship can be set as desired.

At the ends of the axis of rotation 71 are eccentrics 74 attached to which the upper arms 61 the knee lever are mounted. This storage is preferably carried out so that in an extended position of the toggle, the eccentric 74 approximately in the middle between bottom and top dead center (ie at about 90 °) are located. The rotation of the eccentric 74 then ensures a further displacement of the plunger 30 down, whereby the actual pressing force is generated in the nominal force range. Before the eccentric reaches its bottom dead center, the plunger is due to the buckling of the toggle 60 already moved up again.

The drive of the press thus consists of a combination of eccentric and toggle. The toggle 60 is responsible for the relatively low load on the opening and closing movement, the eccentric drive for the working path. Depending on the gear position, areas of a work cycle can be accelerated or delayed.

A particularly advantageous situation arises when the toggle lever 60 in the stretched position remains almost calm and the eccentric 74 at 90 ° its maximum speed passes. This tells the ram 30 a linear application of force without lateral forces.

One possible use for the press is hot forming. By matching the gear ratio, driving through the lower reversal point can be accelerated by 100% or more. This is enormously important for hot forming, since short contact times significantly affect the tool life.

8th shows a representation of the press with press table 10 , two stands 20 , the pestle 30 and a full (left) or partial (right) reproduction of a parallel fix 50 , The parallel fixation 50 In this case comprises at the two plunger ends each have a rod with an upper thickened head 51 , with the rod with its lower end on the plunger 30 and is guided in a hollow spindle 52 °. The hollow spindle is adjustable in the gearhead ° 54. The gear head in turn is located on a spring strip 53 , which at both ends to adjacent stands 20 is attached.

The parallel fixing thus contains an adjustment with a hollow spindle ° 52, which can be synchronized with the adjustment of the ram lifting position, or is synchronized with this. For the absorption of the counterforce, which arises when placing the end head of the rod ° 51 on the hollow spindle 52, (at least) is a spring 53 provided, which is mounted at mid-height of the stand area.

The two bars 51 come due to their heads into abutment with the hollow spindle ° 52 when the plunger 30 enters the nominal force range. This results in the generation of an upward counterforce on the ends of the plunger, through which any tilting and asymmetric pressing forces are compensated. The less loaded side of the ram 30 namely by the rod attached to the plunger 51 lifted with the thickened end head when the head ascends on the hollow spindle ° 52. As a result, a cutting stroke is also effectively prevented.

The plunger parallel fixing is thus fully effective in the range of nominal force. It can balance up to 80% different forces (left-right). This prevents the tappet from swinging through, as well as the tool-damaging vibrations.

In 9 the entire press is shown with all components. In particular, it can be seen that on the stands 20 the press head 80 is arranged, in which the components of the ram drive are stored. Furthermore, the coordinate system is shown in the figure, according to which the lifting movement of the plunger 30 in (vertical) z-direction and the plunger extends longitudinally in the (horizontal) x-direction.

In summary, the described embodiment of the invention thus relates to a press with two or more force-transmitting uprights, in which the guide elements for the plunger are completely removed from the force-transmitting uprights, and the stands are only used for power transmission. The guide of the plunger is taken over by a guide body, which is connected only to the press table. Optional, e.g. with a very long ram (> 5000mm), additional guide bodies oriented only on the press table can be provided.

The ram guide for the x-direction (horizontal left - right) takes place exclusively over a predetermined tilting point, which is at the level of the tool working plane.

The tipping point is by a round part 33 is set to allow the ram to tilt left and right under unequal loading without changing its x position. The said round part, about which the plunger tilts, is centered in a play adjustable sliding block 32 stored. Rundteil and or sliding block can also be roller bearings.

The tipping point in conventional presses is created by an interplay of different power requirements at the connecting rods and the resulting Ständerereinschnürungen. Even during a decline, the power requirement of follower tools, e.g. Cutting, pulling and embossing, back and forth. The ram tilt point varies as well. This is ruled out by the fixed tilting point at working height of the tool.

Furthermore, in the nominal working range, a parallel fixing ensures that the ram is held parallel to the press table despite the large, different pressure load. This is achieved by lifting the plunger on the less loaded side. The setting of the parallel attitude is preferably carried out automatically with adjustment of the ram lifting position.

The sensible nature of the new tappet guide creates the possibility of a more effective and material-saving stator design, linear power transmission and minimal bending stresses.

The press is driven by a combined toggle eccentric drive. The ratio eccentric to toggle lever is preferably adjusted so that the eccentric is about 45 ° in front of and 45 ° after the 90 ° position in the working engagement. After that, the knee lever pushes the eccentric out of the force application and opens the tool for the next work cycle. The press can hit the tool with unrestrained speed without generating a harmful noise level (higher productivity).

Claims (10)

Press for machining workpieces, in particular a multistage press, comprising: - a press table (10); a press head (80); - a plurality of uprights (20) spacing the press head (80) with the press table (10) to form a working space therebetween; - A plunger (30) which is arranged in the working space and in a stroke direction (z) is reciprocally movable; characterized by a guide body (40) directly connected to the press table (10) which guides the plunger (30) in a direction (x) transverse to the stroke direction (z). Press after Claim 1 , characterized in that the plunger (30) is rotatably coupled about a tilting axis (33) and preferably via a sliding block ° (32) with the guide body (40). Press after Claim 2 , characterized in that the tilting axis (33) lies at the level of the working plane. Press for machining workpieces, in particular after at least one of Claims 1 to 3 comprising: a press table (10); a press head (80); - A plurality of stands (20) which connect the press head (80) with the press table (10) at a distance, so that a working space is formed between them; - A plunger (30) which is arranged in the working space and in a stroke direction (z) is reciprocally movable; characterized by a parallel fixing (50) which is attached to transversely to the stroke direction (z) lying ends of the plunger (30) and through which in each case a path-dependent counterforce is exerted in the nominal force range on these ends. Press after Claim 4 , characterized in that the counterforce at the lower low point of the plunger (30) is about 20% to about 40% of the nominal force. Press after one Claims 4 or 5 , characterized in that the parallel fixing (50) at each end of the plunger (30) comprises a rod (51) which on the one hand at said end and on the other hand at least indirectly to a spring (53) is attached. Press after at least one of Claims 4 to 6 , characterized in that the course of the counterforce at each end of the plunger (30) is separately adjustable, preferably by means of a hollow spindle ° (52) in which the rod (51) slides. Press for machining workpieces, in particular after at least one of Claims 1 to 7 comprising: a press table (10); a press head (80); - A plurality of stands (20) which connect the press head (80) with the press table (10) at a distance, so that a working space is formed between them; - A plunger (30) which is arranged in the working space and in a stroke direction (z) is reciprocally movable; characterized by - an eccentric mechanism (70) having an eccentric (74) disposed in the press head (80); - A toggle lever (60) having one end on the eccentric (74) and the other end on the plunger (30) is arranged. Press after Claim 8 , characterized in that the eccentric (74) is located near the middle between its top dead center and bottom dead center when the toggle lever (60) is extended. Press after Claim 8 or 9 , characterized in that the eccentric (74) and the toggle lever (60) are driven by a common drive axle (71).

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