阅读说明：本技术 具有肘杆驱动器和电驱动器的粉末压机 (Powder press with toggle lever drive and electric drive ) 是由 A·韦利 M·佐尔贝格尔 C·梅森 R·哈尼 于 2019-02-25 设计创作，主要内容包括：本发明涉及一种用于从能够被压制的材料生产压制物品的粉末压机(1),具有：压机框架(10)；上部和/或下部冲头组件(14)以及模具组件,所述冲头组件和模具组件限定一个被压制的材料能够被引入到其中的模制腔；以及电驱动单元(12),所述电驱动单元与冲头组件(14)和/或模具组件可操作地连接。为了模制该压制物品,冲头组件(14)和模具组件能够沿着压制轴线(18)相对于彼此移动,并且通过所述电驱动单元(12)彼此压紧。此外,所述电驱动单元(12)和冲头组件(14)之一之间的可操作连接包括肘杆驱动器(16),所述肘杆驱动器(16)将冲头组件(14)沿压制轴线(18)移动到压制末端位置中。(The invention relates to a powder press (1) for producing pressed articles from a material that can be pressed, having: a press frame (10); upper and/or lower punch assemblies (14) and die assemblies defining a molding cavity into which a compacted material can be introduced; and an electric drive unit (12) operatively connected with the punch assembly (14) and/or the die assembly. For moulding the pressed article, the punch assembly (14) and the die assembly are movable relative to each other along a pressing axis (18) and are pressed against each other by the electric drive unit (12). Furthermore, the operative connection between the electric drive unit (12) and one of the punch assemblies (14) comprises a toggle-lever drive (16), the toggle-lever drive (16) moving the punch assembly (14) along the pressing axis (18) into a pressing end position.)

1. A powder press (1) for producing pressed articles from a material that can be pressed has

-a press frame (10);

-an upper and/or lower punch assembly (14) and a die assembly defining a moulding cavity into which the material to be pressed can be introduced; and

-an electric drive unit (12), said electric drive unit (12) being operatively connected with said punch assembly (14) and/or die assembly;

wherein, for moulding the pressed article, the punch assembly (14) and the die assembly are movable relative to each other along a pressing axis (18) and are pressed against each other by the electric drive unit (12),

characterized in that the operative connection between the electric drive unit (12) and one of the punch assemblies (14) comprises a toggle-lever drive (16), the toggle-lever drive (16) moving the punch assembly (14) along a pressing axis (18) into a pressing end position.

2. The powder press (1) according to claim 1, characterized in that the toggle link drive (16) is arranged between the electric drive unit (12) and the punch assembly (14), wherein on a drive train (20) of the electric drive unit (12) first and second levers (22, 24) are rotatably hinged to a first end (26) of the levers (22, 24), respectively, symmetrically with respect to a pressing axis (18), and a first arm (30) for connection to a press frame (10) of the powder press (1) and a second arm (32) for connection to the punch assembly (14) are rotatably hinged to a second end (28) of each lever (22, 24), respectively.

3. The powder press (1) as claimed in claim 1 or 2, wherein the toggle lever drive (16) is kinematically dimensioned such that the pressing force is formed as a function of the pressing movement according to a predefined compression curve (88) in order to produce the pressed article.

4. The powder press (1) according to any one of the preceding claims, wherein the electric drive unit (12) has a spindle drive with a servomotor assembly and a sensor for detecting the rotation angle, the rotation speed and/or the torque for adjusting the servomotor assembly.

5. The powder press (1) according to any one of the preceding claims, wherein at least one position sensor is arranged to detect the position of the punch assembly (14) and to transmit a signal to a control unit for adjusting a servo motor assembly.

6. The powder press (1) according to claim 4 or 5, characterised in that the servomotor assembly is a hollow shaft electric motor in order to produce a controlled rotary drive.

7. The powder press (1) according to any one of the preceding claims, characterised in that the pressing end position can be set by means of a mechanical fixed stop (50) which is height-adjustable and comprises punch carriers configured as cylinders (52) arranged concentrically to one another.

8. The powder press (1) as claimed in claim 7, characterised in that in the pressing end position the lower axial end face surface (60) of the cylinder (52) of the height-adjustable mechanical fixed stop (50) rests respectively on the upper end face surface (62) of an adjusting ring (58) configured in the form of a single-threaded helicoid in order to adjust the height of the mechanical fixed stop (50).

9. The powder press (1) as claimed in claim 8, characterized in that the lower axial end face surface (60) of the mechanically fixed stop (50) with adjustable height is configured to be complementary to the upper end face surface (62) of the adjustment ring (58), so that the adjustment ring (58) is rotated by actuating the drive (70) in order to adjust the height of the mechanically fixed stop (50).

10. The powder press (1) as claimed in any of claims 7 to 9, characterised in that the height of the pressing is adjusted by a synchronous rotation of the adjusting ring (58).

11. The powder press (1) as claimed in claim 10, characterized in that the actuating drive (70) is configured as an electric motor in order to drive the adjusting ring (58) individually and synchronously.

12. The powder press (1) as claimed in any of the preceding claims, characterised in that the toggle lever drive (16) comprises a bearing which is pretensioned by means of a hinge element (36) in order to reduce play in the bearing.

13. The powder press (1) as claimed in claim 12, wherein the hinge element is configured as a solid joint (36), the solid joint (36) having bearing seats (40) which are connected to one another by struts (42) arranged in the form of a diamond.

Technical Field

The present invention relates to a powder press for producing pressed articles from a material that can be pressed.

Background

Typically, a press, particularly a powder press, has a press frame, an upper punch assembly and a lower punch assembly, and a die assembly between the punch assemblies. The punch assembly and the die assembly form a moulding cavity into which a material to be pressed, in particular a powder material, is introduced. For moulding the pressed article, an upper punch assembly and a lower punch assembly comprising at least one tool plane with a tool or respectively at least one punch are pressed against each other, wherein the punch assemblies are moved according to settable pressing parameters. The punch assembly in the simplest case comprises one punch, but usually has a plurality of punches. Assemblies with multiple punches are also known in order to press multiple height levels in a pressing direction, wherein the individual punches move at different speeds and/or stroke distances relative to one another and are received in one tool plane. In the press end position, in which the full press force is applied by the press drive, the punch assembly can be supported by a fixed stop, so that a defined press position is assumed. In the known powder presses, the very high pressing forces and energies required in the pressing direction are generated to a large extent by hydraulic, mechanical or electrical drive systems.

In the case of powder presses for producing dimensionally stable pressed articles, in addition to a drive system for moving the punch assemblies in the pressing direction, there are also provided hydraulically, electrically or otherwise drive-actuating drives known per se for adjusting the respective upper or respective lower punch carriers or the respective punches relative to one another.

Typically, the movement of the powder press is generated mechanically, hydraulically or electrically. The sequence of movements in the mechanical press is substantially predefined, for example by means of a toggle lever drive. In the case of mechanical presses, higher stroke numbers can be achieved with low energy consumption and reasonable maintenance costs. Indeed, the flexibility of movement of the punch assembly is relatively low.

Controlled hydraulic drive systems are used in known hydraulic presses to move each punch assembly independently. Individual movement of a single punch assembly requires high flexibility. Due to the use of the measuring system and the adjustment of the movement sequence based on said measuring system, a high accuracy and mobility is created during the pressing operation. Admittedly, in the case of a hydraulic press, high energy requirements and long cycle times will be required. The punch assembly, with the punch arranged, may be directly supported by a piston/cylinder assembly, wherein, due to the high pressing forces, it is admittedly often necessary to fix a stop. During pressing, the hydraulic cylinder receives a reaction force acting on the punch. In the case of pressed articles of complex shape, the reaction force varies from punch to punch so that a single punch is assigned a separate hydraulic cylinder. Therefore, the hydraulic press includes a plurality of hydraulic cylinders, which requires a complicated system.

The electric press includes an electric drive system for driving, e.g., an electric spindle drive. In this case, an average number of strokes can be achieved with low energy requirements, wherein the pressing operation can have high accuracy and flexibility, and with low space requirements and low maintenance costs.

An electrical powder press is known from EP2311587a1, wherein the upper punch assembly has an upper spindle drive and the die assembly and/or the lower punch assembly has a lower spindle drive. It is also known that a spindle drive comprising a spindle/nut assembly or a nut/spindle assembly is operatively connected to the motor unit, transmitting the rotary motion of the motor unit into a linear movement of the drive train. In general, the spindle nut acts on the upper and/or lower punch plate of the punch assembly via a force transmission device and, together with the upper and/or lower punch plate of the punch assembly, moves the upper and/or lower punch in a main pressing direction, which main pressing axis extends parallel to the longitudinal axis of the spindle at a distance or coaxially with the longitudinal axis of the spindle. A shorter drive train is established by the spindle drive, so that a high stiffness and thus a high mobility of the press drive can be achieved even with a large moving mass and/or a large pressing force.

The motor unit can be a servomotor assembly, wherein in particular a rotation angle sensor for adjusting the rotation angle or a torque sensor for adjusting the torque, respectively, and a position sensor for detecting the linear position of the respective ram are provided. By directional actuation of the individual punches, a flexible process control can be achieved, so that during the pressing operation a constant movement of all the punches and an adaptation to this movement is achieved, taking into account relevant parameters including relevant material parameters.

The powder press with electromechanical drive system may further comprise passive drive elements, such as spindles, belts, gears, eccentric mechanisms and/or toggle levers, arranged between the electric drive unit and the punch assembly to be driven, in order to transfer the pressing force generated by the electric drive as the main pressing force. Indeed, presses with electromechanical drive systems have lower energy requirements than hydraulic presses, but generally only lower stiffness and less mobility can be achieved by passive drive elements. In particular, in the case of servo motor driven powder presses, the following problems exist: the transfer of the rotational movement to the translational movement may be influenced by various physical variables, so that a reliable and defined pressing operation is only possible with high adjustment costs. Furthermore, these powder presses are considered to be prone to failure and wear, especially due to the impact sensitivity of the included spindles, and are therefore expensive. Therefore, non-linear drive systems, in particular toggle drives, are considered unsuitable for use in powder presses, in particular because they generate maximum pressing forces only in a very limited area.

From US2009/0317507a1 a powder press is known, which has a punch carrier plate and a die that are adjustable relative to each other. The electric motors act as their drive in each case, wherein the plates or moulds are connected to the electric motors by means of a central gear and two gears. No passive drive system is provided.

From JP2001-259896 a hydraulic powder press is known, wherein an upper punch assembly and a lower punch assembly are moved by separate or combined hydraulic drive systems. In this case, the vertical movements of the upper punch assembly and the lower punch assembly are coupled to each other by a coupling. A toggle system is arranged between the hydraulic drive and at least the upper punch assembly such that movement of the hydraulic cylinder is transmitted through the toggle system to the die assembly and the punch assembly, wherein the compression force transmitted to the punch assembly is many times greater than the compression force of the hydraulic cylinder used. The included hydraulic drive has proved to be disadvantageous, both because it entails high energy demands and noise, and because it is difficult to maintain due to the high flow of hydraulic oil associated with the toggle lever system.

It is an object of the present invention to provide a powder press for producing pressed articles from a material that can be pressed, which makes it possible to achieve an ideal pressing process according to an optimized compression process of the material that can be pressed, and during which a high compression force can be transmitted.

Starting from the prior art, a powder press for producing pressed articles from a material that can be pressed is proposed, which has a press frame, a tool with an upper and/or lower punch assembly and a die assembly, which define a molding cavity into which the material to be pressed can be introduced. In order to press parts having a complex structure, a plurality of punches are inserted into a die opening of a die assembly from above and/or below, wherein each punch is arranged on a punch carrier which is movable relative to a base carrier or a corresponding bottom plate, respectively. In particular, this is a multi-platform press, in which a single tool plane (also referred to as an additional axis) is moved into a single pressing position during the pressing process. The assembly comprising the punch and the moving and adjusting tool parts carrying said punch, i.e. those elements which are located between the press drive and the punch on the force flux lines and which in particular comprise plates, cylinders, supporting means and guides, is understood to be an additional shafting.

A powder press for producing pressed articles from a material that can be pressed comprises at least one electric drive unit for generating a main pressing force, wherein the electric drive unit is operatively connected to an upper punch assembly and/or a lower punch assembly and/or a die assembly such that the punch assembly and the die assembly are movable relative to each other along a pressing axis and can be pressed against each other.

According to the invention, the operative connection between the electric drive unit and the upper punch assembly comprises a toggle-link drive which moves the upper punch assembly along a pressing axis into a pressing end position.

The electric drive unit according to the invention in combination with a toggle drive for moving at least one punch assembly differs from a hydraulic powder press with a toggle system in the following respects: noise reduction, high energy efficiency and a drive that is largely easy to maintain. The electric drive unit shows an improved level of efficiency, in particular when using a permanent magnet synchronous servo assembly which can be driven with low friction losses. Furthermore, this avoids safety hazards due to hydraulic oil spillage, which is a problem in powder metallurgy. Moreover, this advantageously achieves high accuracy and good repeatability, as well as good and reliable adjustability, and thus results in dynamic motion control of the pressing operation. The operation is also simplified due to the lower risk of operation errors and setup errors.

In an exemplary embodiment, the electric drive unit comprises a spindle drive, wherein the drive motor acts directly on a spindle operatively connected to the toggle drive and in turn on the punch assembly and/or the die assembly. The spindle drive is preferably a controlled spindle drive, as a result of which the properties of the powder material being utilized and the properties of the pressed article produced from the powder material can be taken into account.

The controlled spindle drive is preferably a servomotor assembly with a rotation angle, rotation speed and/or torque sensor in order to adjust the rotation angle, rotation speed and/or torque. Furthermore, these sensors may be arranged to interact with position sensors for detecting the linear position of the respective punch or die, wherein the signals may be transferred to a control unit for adjusting an electric drive unit, such as a servo motor assembly. Thus, the operating parameters may be detected and stored in the storage means and further processed in the processing unit. Furthermore, a further sensor can be provided which detects the spindle position and/or the change in the spindle position, and a sensor device for detecting the spindle torque, which sensor device is designed to initiate an emergency stop or correspondingly to initiate a lost motion. Furthermore, force measuring and/or distance measuring systems may be used, which allow force and/or position based adjustment.

In order to achieve a design that is as compact as possible, the servomotor can be configured as a hollow shaft motor, wherein the element of the spindle drive to be rotated is received inside the hollow shaft.

In order to further develop a powder press with a spindle drive, according to the invention a toggle lever drive is arranged between the spindle and the punch assembly or between a press head and the punch assembly, which may be arranged, so that a higher precision and mobility can be achieved due to the high rigidity in the pressing area. The toggle lever drive is provided as a passive drive element which, together with the electric drive unit, generates the main pressing force exerted by the electromechanical powder press. By combining a passive drive element and an active drive element, the electric drive unit can have a very compact structure. The force applied by the electric drive unit can be reduced by a factor of about 10 compared to a purely electric powder press.

In one embodiment, a servo motor assembly is provided to drive the spindle drive, wherein the kinematics, actuation range, and movement accuracy characteristics provided by the servo motor assembly meet the requirements during the pressing operation. The servomotor assembly can be operated with considerable speed and torque variations, and the servomotor has a high holding torque when stopped. In particular, due to the reduced size of the servomotor assembly used in the powder press according to the invention, an increased mobility can be obtained.

Typically, the servo motor assembly includes a servo inverter for power supply, the size of which is largely dependent on the peak load (peak current) that occurs. This peak load is largely reached in the pressing position. In the electromechanical powder press according to the invention, the peak load is reduced by a factor of about 10 compared to a powder press with direct drive. In the case of a direct drive, the drive is transmitted to the spindle and either directly from the spindle to the punch assembly or through the ram to the punch assembly. The electrical equipment required (e.g., cables and primary fuses) may also be simplified due to the smaller size of the servo motor assembly used by the electromechanical powder press.

Based on the knowledge of the optimum kinematic pressing process for producing a dimensionally stable pressing body, a geometric design of the coupling member of the toggle lever drive according to the invention is provided in cooperation therewith. Thus, the various phases of a press cycle for a particular product can be achieved by directionally dimensioning the geometrical parameters, which, for example, co-operate with one another in the compression phase, the pressurization phase and the pressure relief phase. This kinematics and transmission ratio is close to the ideal process for pressing operations with high repeatability and high speed.

The toggle drives integrated into the electromechanical powder press have a symmetrical configuration, which preferably connect the electric drive unit for generating the main pressing force to the upper piston or to the respective upper punch assembly. Starting from the drive train of the electric drive unit, a first lever and a second lever are each rotatably articulated to a first end of the lever. A first arm for connection to the frame of the powder press and a second arm for connection to the upper punch assembly are each rotatably hinged to the second end of the corresponding rod.

The toggle lever drive is generally characterized by a variable transmission ratio between the applied force and the resultant force. For pressing operations, it is desirable to quickly access the pressing position or correspondingly quickly move out of the pressing end position, wherein the latter facilitates exposure of the pressed molded article. The first part of the press cycle may be effected at an average speed, wherein an average compression force is active. Near the area where the toggle lever drive is fully extended, the final press cycle phase is achieved at low speed and high compression force before the punching end position, which can also be achieved with a small electric drive system. The high transmission ratio in the vicinity of the region in which the toggle lever drive is fully extended allows a precise adjustment of the pressing position. Furthermore, it is advantageous to realize a changing transmission ratio without a transition step or a corresponding interruption, so that a movement during the transition from a rapid shift to a pressing operation is realized without an interruption and is therefore largely continuous. The pressed article can be continuously demolded without being subjected to other stresses, for example, due to the inclusion of gears.

The kinematics of the toggle lever drive can be determined in such a way that: the course of the transmission ratio corresponds to the course of the powder compression, wherein the pressing force is expressed as a function of the pressing movement, in particular increasing with the pressing movement at the end of the powder compression.

Furthermore, the toggle lever drive connected to the powder press must be designed and embodied such that during the pressing step the adjustment of the pressing punch in the pressing direction to a defined end position, i.e. to the pressing end position, can be repeated. In particular, a toggle lever drive which is easy to maintain and has a long service life should be provided, which preferably comprises only a rotary bearing and no linear guides or combined movement sequences.

The setting of the pressing end position is crucial for a successful pressing operation for producing dimensionally stable pressed articles from material substantially in powder form or in granular form. According to the invention, mechanical fixed stops are provided for defining the pressing point of the additional shafting, which mechanical fixed stops define the elevation of the pressed article or of the respective green body. Thus, in the pressing end position, the punch carrier, to which the punch is fixed, is rigidly supported on the mechanical fixed stop or, respectively, is supported on the mechanical fixed stop in a force-transmitting manner, which is therefore configured in one embodiment to be height-adjustable.

Furthermore, the punches or respectively the tools in the powder press are configured to have different lengths and to be subjected to different stresses, so that the tools have to be reground during their lifetime. This requires a press height adjustment, which is usually arranged as an additional drive in the upper part of the press, for example, and thus displaces the entire base of the upper piston in the vertical direction. It is acknowledged that such height adjustments are expensive and further increase the sources of geometrical errors of the machine.

As mentioned above, the problems with powder presses with non-linear drive kinematics, in particular those with toggle drives, are essentially: only in narrow regions, expressed in a tapered manner, is the maximum pressing force achieved at precisely one point. Outside this region or, respectively, outside this point, the generated compressive force is insufficient or, respectively, greatly reduced, or the system cannot be adjusted. According to the invention, in combination with the electromechanical powder press according to the invention, a fixed stop is provided, which makes it possible both to adjust the height of the respective pressing end position of the included punch assembly and thus of the pressed article, and to adjust the height to compensate for wear or warping of the punches used. The adjustable fixed stop arrangement provided according to the invention reduces the complexity of the electromechanical powder press and allows the use of included toggle drives extending relative to the area of the powder press.

The adjustable fixed stop is configured as a cartridge, wherein a plurality of concentric cartridges may be included, which are movable relative to each other. By means of this design, a greater stroke can be achieved with a limited installation space than in the case of elongate elements. By independent movement of the individual drums relative to each other, the height level of the pressed article to be produced can be set and defined. By a synchronous movement of all the drums, the press space is modified, so that a press height adjustment is achieved. This serves to compensate for wear or warping in the case of shorter or longer punches.

In one embodiment, the electric motor is arranged to adjust the drive such that each fixed stop moves independently and/or in a synchronized manner. Thus, an adjustment drive which is often difficult to access can be used in a user-friendly manner by means of the control unit. This is particularly advantageous for the adjustment during automatic operation of the powder press, during which the protective door is closed, since the operator can activate the adjustment drive by means of, for example, the control unit, so that no downtime occurs.

It can be provided that the height adjustment of the fixed stop means is effected by means of an included adjusting ring which is directly or indirectly operatively connected with the adjusting drive. For example, the adjusting ring can be provided with external teeth which engage with corresponding drive wheels of the adjusting drive. For activating the rotary movement of the adjusting ring, a belt drive, a rotor/stator drive, a spindle drive or a piston-cylinder unit are also conceivable.

Furthermore, during production of pressed articles in an electromechanical powder press with a toggle link driver, dimensional stability may be improved since the bearings of the coupling member of the toggle link driver have minimal or eliminated bearing clearances, if possible. Said bearing play, which may occur to varying degrees in the bearings (preferably roller bearings) comprised by the toggle lever drive, tends to operate asynchronously and thus to cause misalignment and malfunction of the press.

In one embodiment of the electromechanical powder press according to the invention, it is provided that the coupling members of the toggle lever drive or respectively the included rods or arms are connected to each other in an articulated manner by means of a hinge, wherein a defined movement of the coupling members during the reception and transmission of forces and moments is carried out with reduced, preferably without, play. This can be achieved, for example, by a defined deformation of the correspondingly designed hinge element. The hinge element may be configured as a solid joint, wherein an elastic region is provided between the bearing seats of the solid joint, which elastic region increases the distance between the bearing seats during application of a force perpendicular to the longitudinal axis of the solid joint. On the other hand, in the mounted state, i.e. without force, the distance of the bearing seats corresponds exactly to the predefined bearing axial distance. According to the invention, the spring region can be formed by struts in the form of diamonds, which connect the bearing blocks, wherein a plurality of struts can also be provided.

Drawings

The invention is explained in more detail below with reference to exemplary embodiments depicted in the drawings, in which:

fig. 1 shows an exemplary depiction of a toggle actuator arranged in a powder press for moving an upper punch assembly;

fig. 2 shows an exemplary depiction of a toggle lever drive according to fig. 1 with a solid joint;

fig. 3 shows an exemplary depiction of a physical joint of the toggle actuator according to fig. 1;

FIG. 4 shows an exemplary depiction of an adjustable fixed stop;

fig. 5 shows a graphical depiction of the compression curve of the powder and the kinematics of the toggle actuator during the stamping operation.

Detailed Description

Fig. 1 shows a top view of the upper part of the powder press 1. Only the upper region of the powder press 1 is depicted in fig. 1, wherein the press frame is generally designated 10 and further comprises an upper press frame 10. On the upper press frame 10, a drive unit 12 is arranged, which is an electric drive unit 12. The powder press 1 comprises a toggle link drive 16 between the upper press frame 10 and the upper punch assembly 14, the toggle link drive 16 being arranged such that it is operatively connected to the drive unit 12 on the one hand and to the upper punch assembly 14 on the other hand in order to move the upper punch assembly 14 in the direction of the pressing axis 18. A drive train 20 extending from the drive unit 12 in the direction of the upper punch assembly 14 is coupled to the toggle lever drive 16.

The included toggle actuator 16 achieves an increased deflection achieved by the actual drive unit 12 by means of a suitable geometric assembly and construction according to lever principle and transmission ratio. Within the framework of the present invention, a toggle link is understood as a device or corresponding element for transmitting and/or transferring forces, which toggle link comprises at least two single-armed levers having a common end point (in general, a pivot point configured to be movable), wherein the free ends of the single-armed levers bearing against one or more bodies can be moved under the influence of a force acting on the common end.

The toggle lever drive 16 comprises, symmetrically with respect to the pressing axis 18, at least one first lever 22 and at least one second lever 24, the first ends of the first lever 22 and the second lever 24 being respectively rotatably hinged to a lever 26 on the drive train 20. A first arm 30 for connection to the upper press frame 10 of the powder press 1 and a second arm 32 for connection to the upper punch assembly 14 are rotatably hinged to the second end 28 of each rod, respectively. Thus, a four-link system is formed that transmits the movement from the drive unit 12 to the upper punch assembly 14 such that the upper punch assembly 14 moves along the pressing axis 18. Included joints are generally designated 34 and are disposed between the arms 30, 32 and the rods 22, 24, as well as to the location of the drive train 20, and are disposed as articulation points to the upper press frame 10 and the upper punch assembly 14. Preferably the joint 34 is a roller bearing. To ensure that the shifting and resulting pressing force is transmitted directly and without play to the upper punch assembly 14, the bearings need to be pre-tensioned through the solid joint 36. The solid joint 36 provides a flexible connection between the first structural component and the second structural component. In fig. 2, the upper part of the powder press 1 is depicted, from which fig. 2 the assembly of the solid joint 36 in the toggle actuator 16 can be seen.

In fig. 3, a solid joint 36 provided in the powder press 1 is schematically depicted separately. In order to achieve a high accuracy of positioning of an object with respect to another object and/or a stationary coordinate system, physical joints 36 within the frame of the physical joint module are known. In general, the solid joint 36 is understood to include a body having points of reduced stiffness. Generally, the reduced stiffness is achieved by a local reduction of the cross-section or by suitable shaping.

According to the embodiment depicted in fig. 3, the solid joint 36 is an elongated element configured to be mirror symmetric about the longitudinal axis 38. The bearing blocks 40 are arranged at a first end and a second end, wherein a shaft or a corresponding axis may be received in the bearings. To produce the required reduced stiffness, struts 42 are provided between the bearing seats 40, spanning between the bearing seats 40, for example in the shape of an oval or a diamond. Other shapes are also conceivable, wherein on the one hand a specific flexibility in a certain area is observed and on the other hand an overall stiffness is observed, so that it is also possible to provide a plurality of struts with a possibly reinforced central area. Due to the shape of the solid joints 36, the distance between the bearing seats 40 can be varied, in particular the distance between the bearing seats 40 can be enlarged, during pressing together of the struts 42 (i.e. during application of a pressure perpendicular to the longitudinal axis 38).

In fig. 4, a fixed stop 50 is depicted in order to clarify the pressed end position. The pressing position limits the position of the components of the tool used in the press, wherein the punches are preferably inserted into the die opening from both sides and compress the material that can be pressed that is introduced into the die opening. The pressing end position is the position where the maximum pressing force acts on the material located in the die opening, preferably by means of a punch. In the pressing end position, in particular, the punch carrier 52 is supported rigidly and in a force-transmitting manner on the fixed stop. In particular, the use of a height-adjustable fixed stop 50 is advantageous.

The punch assembly (e.g., upper punch assembly 14) generally includes a punch carrier 52 to which punches (not shown) are secured in various circumstances. The punch carrier 52 has an attachment surface, which is preferably annular, so that further inner punches or corresponding elements assigned to these punches can be guided through the central through hole 56. Preferably, the assembly is arranged rotationally symmetrically about a pressing axis 18, along which pressing axis 18 the punch can be moved. In fig. 4, an adjustment ring 58 is depicted, which is configured to set the pressing tip position. As a result, in particular tool wear, which would otherwise lead to incorrect pressing, can be compensated. The punch carrier 52 rests with a lower axial end surface 60 on an upper end surface 62 (i.e., a support surface for the adjusting ring 58). The upper face surface 62 of the punch carrier 52 for assignment is configured as a helical ramp in the form of a single-threaded screw face, and the threaded ends 64 and 66 (including the threads) of the screw face are connected by a vertical connecting surface 68. The corresponding axially lower face surface 60 of the punch carrier 52 is complementarily configured. As a result of the rotation of the adjusting ring 58, the assigned punch carrier 52 is raised or lowered, depending on the direction of rotation. As a result, the height of the pressing end position can be modified or set correspondingly by the stroke of the punch carriage 52. In one embodiment of the adjustment ring 58, the adjustment ring 58 may be operably connected to an outer adjustment drive 70 and rotated by the adjustment drive 70. For example, the operative connection may be provided by corresponding teeth of the adjustment ring 58 and a drive wheel of the adjustment drive 70. Belt drive, spindle drive, direct drive adjustment ring 58 are also contemplated. The adjustment drive 70 may be an electrically actuated drive which makes it possible to determine the pressing tip position individually. However, a plurality of adjusting drives 70 can also be coordinated with one another by means of a control unit provided, so that a synchronized height adjustment of a plurality of punch carriers 52 can be achieved.

Fig. 5 shows a force-path diagram 80 in order to illustrate the pressing operation in the powder press 1. In the force-path diagram, the y-axis assigned to the force to be applied is labeled 82. The press stroke is depicted on the x-axis and is labeled 84. For the most part, no pressing force is required during the initial stages of the pressing cycle until the upper punch assembly or corresponding tool impacts the material filled in the die assembly that can be pressed. This initial phase should be implemented as quickly as possible, since this makes it possible to reduce the cycle time. For the pressing operation, the pressing force is increased and a gradually increasing pressing force course is shown, wherein in the pressing end position the maximum pressing force is achieved. Accordingly, a high force is achieved by a minimum pressing stroke in the region of the pressing end position. This process is labeled 88 in the depiction and depends inter alia on the powder material that can be compacted and the fill level.

This process of force-to-path ratio is accomplished in a nearly optimal manner by the toggle actuator 16, as depicted by the curve 90. It can thus be moved at high speed and with low force over a long distance in the initial phase until the dead point of the toggle lever mechanism is approached. In the region of the dead point, i.e. in the position in which the included lever or respectively the arm is virtually straight, a large pressing force can be transmitted. Here, only the smallest distances are covered, but the transmittable pressing force is actually the largest. Furthermore, the arrangement of the toggle lever mechanism 16 allows for moving in or respectively out of the pressing end position at high speed, so that the cycle time as a whole is shortened.

In fig. 5, a force-path curve 90 shows a corresponding course of a toggle lever drive with an adapted transmission ratio. By adapting the gear and lever ratios of the toggle actuator, a nearly ideal pressing operation process can be achieved, as exemplified by the process 88 of powder compression, wherein the optimized force-path curve 90 is always above the powder compression curve 88.