EP2511023B1 - Hydraulically operated setting device with a hydraulic aggregate and a joining method for connecting at least two components - Google Patents

Description

1. Field of the invention

The present invention relates to a hydraulically operated setting tool with a hydraulic unit for establishing a connection between at least two components, in particular a rivet setting device, a joining method for connecting at least two components, in particular a setting method for a punch rivet or a clinch, using the hydraulically operated setting device and a Joining connection between at least two components that has been produced by means of the hydraulically operated setting device or the joining method.

2. Background of the invention

The present invention relates to a hydraulically operated setting tool, which is supplied by means of a hydraulic unit, the driving hydraulic fluid. This hydraulic fluid supplies a piston-cylinder arrangement of the setting device, which moves both a punch for introducing a connecting element, such as a punch rivet, as well as a hold-down. For this purpose, the setting device is connected to the hydraulic unit. The hydraulic power unit includes a tank for storing hydraulic fluid, such as oil. In addition, the hydraulic unit is equipped with a pump that pumps hydraulic fluid from the tank to the setting device. Since the setting device is usually arranged on an industrial robot, connect long hydraulic hoses for guiding the hydraulic fluid, the hydraulic unit with the setting tool. Depending on the pressure and the volume flows of the hydraulic fluid, which can be generated by means of the hydraulic unit, certain cycle times result, which are required, for example, for setting a punch rivet in at least two components. Furthermore, the tact time for a setting operation is influenced by the speed of the hydraulic cylinders in moving the punch and the blank holder.

An electromotive hydraulic drive and a method for providing a defined hydraulic pressure and / or volume is described in DE 10 2009 040 126 A1 , which forms the basis for the preamble of claims 1 and 10. The hydraulic drive comprises a hydraulic cylinder with a piston which is linearly movable within the hydraulic cylinder via a rotational movement of an electrically driven spindle. The piston divides the cylinder into a spindle facing away from the spindle and a spindle-facing working chamber. The spindle-facing working chamber has a first hydraulic opening and the spindle-facing working chamber has a second hydraulic opening. About this hydraulic openings, the component is selectively operable with hydraulics.

Since the cycle times of known setting tools with a hydraulic unit are not satisfactory, it is an object of the present invention, a setting device with hydraulic unit and to provide a joining method for joining at least two components which, compared to the prior art, require a shorter cycle time for establishing a connection between at least two components.

3. Summary of the invention

The above problem is solved by a hydraulically operated setting tool with a hydraulic unit for establishing a connection between at least two components, in particular a Nietsetzgerät, according to the independent claims 1 and 4. Furthermore solves the joining method according to the invention for connecting at least two components, in particular a setting method for a punch rivet and a clinching, according to the independent claim 13 above object. In addition, the present invention comprises a joint connection between at least two components, in particular a punched rivet or clinch connection, according to claims 19 and 20, which have been produced with the above-mentioned joining method or the above-mentioned hydraulically operated setting tool. Advantageous embodiments and further developments of the present invention will become apparent from the following description, the accompanying drawings and the appended claims.

The hydraulically operated setting device according to the invention with a hydraulic unit for establishing a connection between at least two components, in particular a rivet setting device, comprises the following features: the hydraulic unit with a tank for hydraulic fluid, a pump for pumping the hydraulic fluid to the setting device, at least one pump hose, the tank connected via the pump and a valve block with the setting device, and a tank hose which connects the tank via the valve block with the setting device, a double-acting cylinder with a Vorhubkammer and a Rückhubkammer in which the piston with piston rod is movably arranged, the one punch of the setting device moves, a single-acting cylinder with a hold-down chamber in which a plunger is movably arranged, which moves a hold-down, wherein the valve block comprises a plurality of valves, via which the return stroke chamber with the pump and the Niederhalterka mmer is connectable, so that a flow of hydraulic fluid from the hold-down chamber supports a return movement of the piston.

During a setting process, hydraulic fluid is first pumped into the prestroke chamber of the double-acting cylinder, the piston rod of which moves the plunger in the setting direction to the components to be connected. The displaced during this process from the return stroke of the double-acting cylinder volume of hydraulic fluid is the Vorhubkammer and the hold-down chamber supplied to support the delivery of the piston and punch and the blank holder in the setting direction, preferably to accelerate by the additional volume flow of hydraulic fluid. For this purpose, the double-acting cylinder for moving the punch of the setting device is designed as a differential cylinder whose piston area without piston rod in the Vorhubkammer is greater than the piston area with piston rod in the return stroke.

After moved by a sufficiently high hydraulic pressure in the Vorhubkammer the punch to the components and a connection between the two components has been prepared, both the plunger on the double-acting cylinder as well as the hold-down on the plunger against the setting direction must be reset to a begin new connection process. While he moves plunger with hold-down against the setting direction within the hold-down chamber, hydraulic fluid is displaced from the hold-down chamber. According to the invention, this displaced volume of hydraulic fluid is supplied to the return stroke chamber of the double-acting cylinder in order to increase the hydraulic volume flow which resets the piston with plunger counter to the setting direction. This increased volume flow of hydraulic fluid accelerates the movement of the piston in conjunction with the plunger.

Since the cycle time of a setting process from the duration of the movement of the punch from its initial position results in the joining position for establishing the connection and back to its original position, the movement of the piston with punch is accelerated by the above-described line of hydraulic flow rates and thus the Tact time shortened.

According to a preferred embodiment of the hydraulically operated setting tool, the hold-down device is mechanically coupled to the punch in such a way that the punch engages the hold-down device in a movement opposite to the setting direction entrains and / or the hold-down carries the punch in a movement in the setting direction. On the one hand, due to this mechanical coupling, the volume flow of the hydraulic fluid introduced into the hold-down chamber assists in moving the punch in the setting direction. On the other hand, the entrainment of the blank holder by the punch promotes the displacement of hydraulic fluid from the hold-down chamber, which is then fed to the return stroke chamber of the piston. This volume flow of hydraulic fluid conducted from the hold-down chamber into the return stroke chamber ensures an accelerated return of the piston with punch to its starting position in comparison with known setting tools.

According to a further preferred embodiment, the valve block for switching the volume flows of the hydraulic fluid is arranged adjacent to the setting device, so that the pump hose and the tank hose between the tank and valve block have a length of 5-30 m, preferably 8-22 m. Both the pump hose and the tank hose serve to circulate the hydraulic fluid between the setting device and the hydraulic unit. Due to the length of the hoses they can absorb a certain volume of hydraulic fluid. Since the pump hose and the tank hose are made of a flexible material that can withstand the flow of volume flows of approx. 20-30 l / min and pressures of up to 300 bar in the hydraulic fluid, the pump and / or tank hose also serve as hydraulic fluid. Energy storage in which hydraulic fluid can be trapped under a certain pressure and then selectively released at a given time. This sudden release of the pressurized hydraulic fluid from the pump and / or the tank hose preferably serves to accelerate the feed movement of the punch to the components to be connected. In addition, it is preferred to enclose in the pump and / or tank hose the hydraulic fluid under pressure from the preceding setting process in order to avoid energy loss by relieving the hydraulic fluid and discharging the hydraulic fluid into the tank of the hydraulic unit.

According to a further embodiment of the setting device according to the invention, the valve block via a plurality of hoses with at least the Vorhub-, the Rückhub- and the hold-down chamber connected, each having a length of 0.15-6 m, preferably from 0.3 to 3 m.

The valve block and the valves realized therein control the volume flow of hydraulic fluid into the different chambers of the setting device. The selective shortening of the hydraulic hoses between the valve block and the cylinders of the setting device shortens the switching times of the hydraulic fluid at the setting tool. The volume flows of the hydraulic fluid controlled by the valve block do not first have to pass through the pump and tank hose in order to activate the activated function in the setting tool. Instead, the hydraulic fluid controlled and released by the valve block retracts only a short distance to the setting tool, so that the time between valve actuation and corresponding reaction of the setting device is shorter compared to conventional systems. As soon as a valve releases a volume flow of hydraulic fluid, this volume flow arrives immediately in the desired chamber due to the short connecting hoses between the valve block and the pre-stroke, return stroke and hold-down chamber of the setting device, in order to generate the desired movement there. The preferred lengths of connecting hoses between the valve block and setting tool also ensure reduced pressure and energy losses of stored energy in the hydraulic fluid.

It is further preferred to design the valve block as a strain relief component for the setting device in relation to the connected pump hose and the connected tank hose. In addition, preferably, the valve block comprises at least two pressure sensors, with which pressure in each of the Vorhubkammer and the hold-down chamber can be detected. According to a further preferred embodiment of the present invention, the valve block of the hydraulically operated setting device is integrated in a cylinder arrangement consisting of the double-acting cylinder and the single-acting cylinder of the setting device. With this construction, the hoses between the valve block and the pre-lift, return and hold-down chambers can be further shortened or even eliminated. This structural configuration shortens the paths to be traveled by the hydraulic fluid between switching valves and the double-acting cylinder which moves the plunger, as well as the cylinder with plunger that holds the hold-down emotional. In addition, such a compact arrangement results in a small interference contour of the setting device fastened to, for example, an industrial robot.

The present invention also comprises a hydraulically operated setting device with a hydraulic unit for establishing a connection between at least two components, in particular a rivet setting device comprising the following features: a) the hydraulic unit with a tank for hydraulic fluid, a pump for pumping the hydraulic fluid to the setting device, at least a pump hose which connects the tank via the pump and a valve block with the setting device, and at least one tank hose which connects the tank via the valve block with the setting device, b) a double-acting cylinder with a Vorhubkammer and a Rückhubkammer, in which the piston c) a single-acting cylinder with a hold-down chamber, in which a plunger is movably arranged, which moves a hold-down, wherein d) the valve block adjacent to the setting device and arranged over a Mehr number of hoses is connected to at least the Vorhub-, the Rückhub- and the hold-down chamber, each having a length of 0.15-6 m, preferably from 0.3 to 3 m.

According to a not belonging to the invention embodiment of the above-described setting tool specifically the hydraulic hoses between the valve block and the cylinders of the setting device were shortened. On this constructive basis, the switching times of the hydraulic fluid are reduced at the setting tool. The volume flows of the hydraulic fluid controlled by the valve block do not first have to pass through the pump and tank hose in order to activate the activated function in the setting tool. Instead, the hydraulic fluid controlled and released by the valve block retains only a relatively short distance compared to the tank hose and pump hose to the setting tool, so that the time between valve actuation and corresponding setting of the setting device is shorter compared to conventional systems. As soon as a valve releases a volume flow of hydraulic fluid, this volume flow arrives immediately in the desired chamber due to the short connecting hoses between the valve block and the pre-stroke, return stroke and hold-down chamber of the setting device, in order to generate the desired movement there. The preferred lengths of connecting hoses between valve block and setting tool provide also for reduced pressure and energy losses of stored energy in the hydraulic fluid.

In a further preferred embodiment, the alternative setting device comprises the pump hose and the tank hose between the tank and pump and valve block with a length of 5-30 m, preferably 8-22 m. In addition, according to a further preferred embodiment, the valve block comprises a plurality of valves, via which the return stroke chamber with the pump and the hold-down chamber is connectable, so that a Voluemnstrom the hydraulic fluid from the hold-down chamber supports a return movement of the piston. These preferred structural embodiments have already been explained above in connection with the first alternative of the setting tool according to the invention and apply in the same way to the second alternative of the setting tool.

The present invention also discloses a joining method for joining at least two components, in particular a setting method for a punch rivet, by means of a hydraulically operated setting device with a hydraulic unit, comprising the following features: the hydraulic unit with a tank for hydraulic fluid, a pump for pumping the hydraulic fluid to Setting device, at least one pump hose, which connects the tank via the pump and a valve block with the setting device, and a tank hose, which connects the tank via the valve block with the setting device, a double-acting cylinder with a Vorhubkammer and Rückhubkammer, in which the piston with Piston rod is arranged to move the punch movable, a single-acting cylinder with a hold-down chamber in which a plunger is arranged to move a hold-down movable, wherein the valve block comprises a plurality of valves, via which the return stroke chamber the pump and the hold-down chamber is connectable, wherein the setting method comprises the steps of: a) introducing a first hydraulic volume flow of the hydraulic fluid in the Vorhubkammer and the hold-down chamber, so that the plunger with plunger and the plunger with hold-down from an initial position are moved in the setting direction , b) connecting the return stroke chamber with the pre-stroke chamber and the hold-down chamber in step a), so that a first hydraulic return flow of the hydraulic fluid from the return stroke chamber in the Vorhubkammer and / or the hold-down chamber is redirected; c) increasing the hydraulic pressure in the pre-stroke chamber after the hold-down and the punch engage a component to be connected, and establishing a connection by setting the fastener in the component or deforming the component; d) introducing a second hydraulic volume flow of the hydraulic fluid into the return stroke chamber, so that the piston is moved in the direction of home position, and e) connecting the holddown chamber with the return stroke chamber in step d), so that a second hydraulic return flow of the hydraulic fluid from the holddown chamber is diverted into the return stroke chamber and supports the movement of the piston to the starting position.

With the aid of the method according to the invention, the volume flows during the advancement of the punch and hold-down in the setting direction and the provision of punches and hold-downs opposite to the setting direction are specifically diverted that these flow rates of the hydraulic fluid support the movement of the piston with punch in the respective direction, preferably accelerate. For this purpose, the volume of hydraulic fluid displaced from the return stroke chamber is supplied to the hold-down chamber and / or the prestroke chamber of the double-acting cylinder during delivery of the piston with plunger to the components to be connected. This supplied volume flow of hydraulic fluid from the Rückhubkammer increases the provided by the pump volume flow of hydraulic fluids, so that the movement of the double-acting cylinder and / or the plunger is accelerated with hold-down. In addition, in the return movement of the double-acting cylinder to its original position, the volume of hydraulic fluid displaced from the return stroke chamber by the plunger with hold-down device is fed to the return stroke chamber of the double-acting cylinder. This additional volume flow also ensures an accelerated return of the piston with punch to its starting position. This targeted diversion of volume flows of hydraulic fluid produces a faster movement of the piston with punch and the plunger with hold-down, whereby the cycle time of a joining operation compared to the prior art is reduced.

According to a preferred embodiment of the present joining method entrainment of the plunger with hold-down by the piston with piston rod and Stamp, when the piston moves back to its original position. In this connection, it is preferable to start the above-mentioned step e) as soon as the entrainment of the plunger with hold-down takes place and the plunger displaces hydraulic fluid from the hold-down chamber.

According to a further preferred embodiment of the joining method according to the invention, an overpressure hydraulic volume is generated in the pump tube under increased pressure in comparison to a hydraulic pressure in the pump tube during the movement of the punch and holddown in step a) and the overpressure hydraulic volume during the start of step a) Start of step a) relaxed, so that the movement of the piston with punch and the plunger is accelerated with hold-down. As already mentioned above, at least the pump hose serves as an energy store for a pressurized volume of hydraulic fluid. This is based on the flexible material from which the pump and tank hose are constructed. In addition, this flexibility of the hoses is specifically exploited by arranging valves in the course of the pump hose and / or the tank hose so that a certain volume of hydraulic fluid can be trapped in the area between these valves under a preselected pressure or residual pressure upon completion of a setting operation. The energy thus stored in the hydraulic volume is selectively released by opening at least one of the valves at a specific time, so that the pressurized hydraulic volume relaxes in the direction of the opened valve and / or this hydraulic volume to assist the movement of the punch and / or or the hold-down contributes.

According to a further embodiment of the joining method according to the invention, the hydraulic fluid and the components of the hydraulic fluid circuit, in particular the valve block, the valves and the hoses are heated to a desired operating temperature, in which the hydraulic fluid via the pump tube, a pressure relief valve in the valve block and the tank hose in the tank is pumped and heated by an increase in pressure before and a pressure relief after the pressure relief valve.

The present invention also comprises a joint connection between at least two components, in particular a stamped rivet or a clinch connection, which has been produced with the above-described joining method or the above-described hydraulically operated setting device with hydraulic unit.

4. Brief description of the accompanying drawings

Figur 1

eine schematische Darstellung einer bevorzugten Ausführungsform des hydraulisch betriebenen Setzgeräts mit Hydraulikaggregat,

Figur 2

eine vereinfachte Darstellung des hydraulisch betriebenen Setzgeräts aus Figur 1,

Figur 3

eine Darstellung von einzelnen Sequenzen einer bevorzugten Ausführungsform des erfindungsgemäßen Fügeverfahrens und

Figur 4

eine bevorzugte Ausführungsform des Fügeverfahrens in Form eines Flußdiagramms.

The preferred embodiments of the present invention will be explained in detail with reference to the accompanying drawings. Show it:

FIG. 1

a schematic representation of a preferred embodiment of the hydraulically operated setting device with hydraulic unit,

FIG. 2

2 is a simplified representation of the hydraulically operated setting device from FIG. 1,

FIG. 3

a representation of individual sequences of a preferred embodiment of the joining method according to the invention and

FIG. 4

a preferred embodiment of the joining method in the form of a flow chart.

5. Detailed Description of the Preferred Embodiments

FIG. 1 shows a schematic representation of the hydraulically operated setting device S with hydraulic unit 10. The hydraulic unit 10 includes a tank 14 with a known hydraulic fluid, such as oil. In addition, the hydraulic unit has a pump 12 with which hydraulic fluid is pumped from the tank 14 to the setting device S via a line 13. The hydraulic fluid is conveyed via a pump hose 16 to the setting device S. From the setting device S back flowing hydraulic fluid passes through a tank hose 18 in the tank 14 for hydraulic fluid.

Between the hydraulic unit 10 and the setting device S, a valve block 20 is arranged, which controls the volume flows of the hydraulic fluid, which are exchanged between the hydraulic unit 10 and setting device S. The valve block 20 controls over a plurality of valves, the volume flow of the hydraulic fluid from the hydraulic unit 10 in the different areas 34, 36, 44 of the setting device S. In addition, the valve block controls the different volume flows of hydraulic fluid between the different areas 34, 36, 44 of the setting device and the setting device S to the tank 14 of the Hydraulic unit 10.

The setting device S has a double-acting cylinder 30. A piston 32 of the double-acting cylinder 30 divides the double-acting cylinder 30 into a prestroke chamber 34 and a return stroke chamber 36. The piston 32 is in accordance with FIG. 1 provided on its underside with a piston rod which is connected to a punch 38. Due to this construction, the piston surface A ₁ adjacent to the prestroke chamber 34 is larger than the piston surface A ₂ adjacent to the return stroke chamber 36.

In addition, the setting device S comprises a single-acting cylinder 40. In a hold-down chamber 44 of the single-acting cylinder 40, a plunger or plunger 42 is arranged. The plunger 42 is connected to a hold-down 48, which serves to fix the components B to be connected before, during and / or after the connection of the components B.

The setting device S is connected to an industrial robot R, which moves the setting device S to the respective joints. Preferably, the setting device S has a C-frame. It is understood that the setting device S is also equipped with a force sensor and a displacement sensor to detect the joining force applied by the punch 38 and the path traveled by the punch 38 during the joining operations. In the same way, it is preferable to equip the setting device S with a feeding device for connecting elements, in particular punch rivets or bolts. The feeding device is designed to supply connecting elements of one or different geometries to the setting device S.

The setting device S establishes a connection between the components B by moving the punch 38 in the setting direction, that is, in the direction of the components B. This connection will For example, realized by means of punch rivets or bolts, while it is also preferred to establish a connection between the components B by clinching.

The valve block 20 for controlling the volume flows of the hydraulic fluid and thus the resulting pressures of the hydraulic fluid in the Vorhub- 34, return stroke 36 and hold-down chamber 44 is adjacent to the setting device S and remote from the hydraulic unit 10. Therefore, the pumping tube 16 and the tank tube 18 have a preferred length of 5-30 m between the hydraulic unit 10 and the valve block 20. According to another preferred embodiment, the pump tube 16 and the tank tube 18 have a length of about 15-20 m.

According to an alternative present invention, the valve block 20 is disposed adjacent to the setting device S, d. H. the valve block 20 is preferably fastened to the setting device S or integrated into the cylinder arrangement 30, 40 of the setting device S. According to another preferred embodiment, the valve block 20 is arranged on the C-frame of the setting device S or on the robot R adjacent to the setting device S. Due to this arrangement of the valve block 10 are for the hydraulic lines 52, 54, 56 only hose lengths of 0.15-6 m, preferably from 0.3 to 3 m, required that the valve block with the Vorhub- 32, the Rückhub- 36th and the hold-down chamber 44 connect. This constructive embodiment is also preferably used in addition to the further alternative of the setting device S according to the invention described below.

By means of the pumping hose 16 and the tank hose 18, the setting device S is connected to the hydraulic unit 10. The above-mentioned length of the pump tube 16 and the tank tube 18 ensures any arrangement of the hydraulic unit 10, in which nevertheless a reliable supply of the setting device S is ensured with hydraulic fluid. The pump tube 16 and the tank tube 18 ensure that a sufficiently large volume of hydraulic fluid is present on the valve block 20 for the control of the setting device S through the valve block 20.

The relatively short compared to the pump 16 and tank hose 18 connecting hoses or - lines 52, 54, 56 realize between the valve block 20 and the setting device S. a faster reaching the setting device S by the controlled volume flow of hydraulic fluid as well as a faster pressure build-up in the hydraulic fluid in the setting device S compared to longer hoses. The faster pressure build-up and the associated shorter switching times for the operation of the setting device S result in shorter cycle times for establishing a connection compared to conventional setting tools.

Preferably, the double-acting cylinder 30 is operated in a first differential circuit. For this purpose, the surfaces A ₁ and A _{2 of} the piston 32 adjoining the prestroke chamber 34 and the return stroke chamber 36 are of different sizes. For example, if the same hydraulic pressure in the Vorhub- 34 and Rückhubkammer 36, act due to the different sized areas A ₁ , A _{2 of} the piston 32 on both sides of the piston 32 opposite different sized forces moving the piston 32. According to one embodiment, the area ratio Φ of the areas A ₁ to A _{2 of} the piston 32 of the double-acting cylinder 30 is in the range of 1.1-1.8, preferably 1.15 to 1.4.

The different sized forces on the surfaces A ₁ , A _{2 of} the piston 32 have the consequence that the piston 32 is moved in the direction of greater force. The movement of the piston 32 produced by the action of the larger force is preferably further assisted in that a volume flow of the hydraulic fluid is introduced into the chamber 34, 36, 44 of the greater force effect. In this way, the movement of the piston 32 is accelerated without the force effect is significantly changed.

According to a further alternative of the setting device according to the invention, the return stroke chamber 36 and the hold-down chamber 44 are connected to each other via a second differential circuit. This structural design is also preferably used in addition to the above-described alternative of the setting device S according to the invention.

The bottom A _{2 of} the piston 32 and the top of the plunger 42 preferably have an area ratio Φ ₂ of 1.5-5, preferably 1.8-3.6.

To assist the first and second differential circuits, the piston rod of the piston 32 with punch 38 and the plunger 42 with hold-down 48 are mechanically coupled together. The mechanical coupling 39 is designed such that the plunger 42 with hold-down 48 during a movement in the setting direction thus to the components B to, the piston 32 via the piston rod and the punch 38 entrains. During a movement of the piston 32 with punch 38 counter to the setting direction, ie away from the components B, the piston 32 drags the plunger 42 and the holding-down device 48 via the punch 38.

By entrainment hydraulic fluid is displaced as a volume flow from the return stroke chamber 36 or the hold-down chamber 44. The pump 12 is first connected via the pumping tube 16 with the Vorhubkammer 34 and leads her to a constant volume flow of hydraulic fluid. In order to support or accelerate the movement of the piston 32 with punch 38 in the setting direction generated by the first differential circuit, the hydraulic fluid displaced from the return stroke chamber 36 is supplied to the prestroke chamber 34. In another operating state, the pump 12 is connected via the pump tube 16 with the return stroke chamber 36, so that the punch 38 entrains the hold-48. In order to assist and accelerate the movement of the piston 32 with punch 38, generated by the second differential circuit, counter to the setting direction, the hydraulic fluid displaced from the hold-down chamber 44 is supplied to the return stroke chamber 36. The respective increased volume flow of hydraulic fluid provides for an acceleration of the already occurring movement of the piston 32 in one or the other direction.

In order to be able to reliably monitor the pressure states in the different chambers 34, 36 and 44 of the setting device S, at least the pre-stroke chamber 34 and the hold-down chamber 34 are each connected to a separate pressure sensor. It is also preferred to equip the return stroke chamber 36 with a pressure sensor.

According to a further preferred embodiment, the valve block 20 is not only the connection of pumping tube 16 and tank hose 18 with the setting device S. Rather, the valve block 20 also realized a strain relief with respect to the pumping tube sixteenth and the tank hose 18, so that the tensile forces generated via the pumping tube 16 and the tank hose 18 are not transmitted to the setting device S.

According to a further preferred embodiment, the valve block 20 is integrated with its plurality of valves in the cylinder assembly 30, 40 consisting of the double-acting cylinder 30 and the single-acting cylinder 40. On this constructive basis, the valve block 20 need not be arranged as a separate part on the setting device S or in the vicinity of the setting device S, for example on its C-frame or robot R. The pump tube 16 and the tank tube 18 are then connected directly to the cylinder assembly 30, 40 of the setting device S with integrated valve block 20. On this structural basis, it is possible to further reduce the interference contour of the setting device S, in order to obtain greater flexibility in reaching joints where components B are to be connected to one another.

A preferred embodiment of the joining method according to the invention is based on Figures 2-4 out. FIG. 3 shows a schematic representation of the joining method based on six selected states of the setting device S, which illustrate the successive process steps 1-6. FIG. 2 contains the explanation of the schematic in FIG. 3 illustrated hydraulically operated setting device S. FIG. 4 illustrates a preferred embodiment of the joining method according to the invention in a flow chart.

Referring to FIG. 2 is the hydraulically operated setting device S simplified schematically shown. On the presentation of the hydraulic unit 10 has been omitted in this case. It goes without saying, however, that in FIG. 2 shown hydraulically operated setting device S is supplied via the pumping tube 16 and the tank hose 18 of the hydraulic unit 10 with the pump 12 and the tank 14 with hydraulic fluid.

The hydraulically operated setting device S of FIG. 2 includes the double-acting cylinder 30 in which the piston 32 is arranged. The piston 32 divides the double-acting cylinder 30 into the pre-stroke chamber 34 and the return stroke chamber 36. The pre-stroke chamber 34 is supplied with hydraulic fluid via the port 52, while the return stroke chamber 36 is supplied with hydraulic fluid via the port 54 is supplied. The piston 32 is connected on one side with a piston rod, which in turn is connected to the punch 38. In addition, the hydraulically operated setting device S, the single-acting cylinder 40, in which the plunger or plunger 42 is arranged. The plunger 42 moves within the hold-down chamber 44, which is supplied via the port or line 56 with hydraulic fluid. The plunger 42 is connected to the hold-down 48. Piston rod or punch 38 and hold-down 48 are mechanically coupled to each other at the point by the reference numeral 39 that the hold-down during movement in setting direction, the piston 32 entrains and upon movement of the piston 32 against the setting direction of the punch 38, the hold-48 and entrains the plunger 42. Seen on the underside of the punch 38 in the setting direction, a punch rivet N is schematically arranged. Upon further movement of the punch in the setting direction of the punch rivet N is placed in the components B. The hydraulically operated setting device S is connected to the hydraulic unit 10, whose pump 12 delivers hydraulic fluid from the tank 14 via the valve block 20 to the setting device S at a constant delivery rate. The delivery rate of the pump 12 is preferably in the range of 15-30 L / min.

In an optional preparation step for the hydraulically operated setting tool S, the hydraulic fluid is heated in step S0 to avoid operational fluctuations due to changes in the temperature of the hydraulic fluid. For this purpose, the hydraulic fluid is moved in a circuit between the hydraulic unit 10 and the valve block 20. By blocking the lines 52, 54, 56, the valve block 20 prevents the hydraulic fluid to be heated from reaching the setting device S. Within the valve block 20, a pressure relief valve, preferably an adjustable proportional valve is provided. The pump 12 pumps the hydraulic fluid from the tank 14 via the pumping line 16 to the valve block 20. By the pressure relief valve, the hydraulic fluid is blocked, so that the pressure on the valve block 20 increases. Preferably, the pressure increases up to a range of 70-150 bar in the hydraulic fluid, more preferably up to 125 bar. As soon as the pressure in the hydraulic fluid on the valve block 20 exceeds the set pressure value, the pressure relief valve releases the hydraulic line so that the pressure in the hydraulic fluid degrades after the pressure relief valve and the hydraulic fluid flows back into the tank 14 via the tank line 18. Since the valve block 20 is arranged directly on the setting device S, approximately 90% of the hydraulic fluid is circulated through the pressure relief valve in the valve block 20 moves. Since the pressure in the hydraulic fluid rises in front of the pressure relief valve and decreases again after the pressure relief valve, the hydraulic fluid is heated by the pressure change. At a pressure change of 100 bar, the hydraulic fluid heats up by 6 K.

It is preferable to move the hydraulic fluid in the cycle between hydraulic unit 10 and pressure relief valve of valve block 20 over a period of 10-15 minutes until the desired operating temperature of preferably 30-60 ° C., in particular approximately 40 ° C., of the hydraulic fluid is reached is. During the circulation of the heated hydraulic fluid, the pump hose 16, the tank hose 18, the valve block 20 and the valves arranged therein are also heated and brought to the desired operating temperature. The remaining in the setting device S amount of hydraulic fluid is relatively low compared to the heated amount of hydraulic fluid, so that it mixes with the operation of the setting device with the heated hydraulic fluid and thereby also briefly reaches the operating temperature of the heated hydraulic fluid. In this case, then the cylinder assembly 30, 40 of the setting device S is brought to the desired operating temperature.

In the FIG. 3 shown components of the hydraulically operated setting device S correspond to the components of the setting device S. FIG. 2 , For clarity, was in FIG. 3 disclaimed the reference numerals. A preferred embodiment of the joining process proceeds in the following steps:
First, the setting device S is an auxiliary joining part N, for example, a punch rivet or bolt supplied.

In step S1 of in FIG. 3 illustrated joining method, the Vorhubkammer 34 and the hold-down chamber 44 via the pump 12 and the terminals 52 and 56 are supplied with hydraulic fluid. Preferably, the pre-stroke chamber 34 and the hold-down chamber 44 are each preceded by a proportional valve to the maximum pressure of the hydraulic fluid to be able to adjust in both chambers. According to one embodiment, the hydraulic pressure is set in the range of 20-80 bar.

In addition, the return stroke chamber 36 is connected to the pre-stroke chamber 34 and optionally to the hold-down chamber 44. From this connection results in the same hydraulic pressure in the Vorhubkammer 34, the Rückhubkammer 36 and the hold-down chamber 44. The differences in the piston surfaces A ₁ and A _{2 of} the piston 32 (see above) cause the piston 32 is moved with punch 38 in the setting direction , About the mechanical coupling 39 between the blank holder 48 and the punch 38 of the hold-down 48 drags the punch 38 with piston 32 with. The plunger 42 contributes in this way to the movement of the piston 32 with punch 38 in the setting direction. The connection between the return stroke chamber 36 and the Vorhubkammer 34 and hold-down chamber 44 provides an increased volume flow of hydraulic fluid in the Vorhubkammer 34 and the hold-down chamber 44, since the displaced from the Rückhubkammer 34 hydraulic fluid is redirected there. This accelerates the movement of the piston 32 and the plunger 42 in the setting direction compared to the operation without flow communication between the chambers 34, 36, 44th

As soon as the hold-down 48 touches down on the components B, the hydraulic fluid displaced from the return stroke chamber 36 flows solely into the pre-stroke chamber 34. The hold-down 48 is applied to the components via the plunger 42 and the hydraulic pressure applied to the hold-down chamber 44 in the range of 0-120 bar B and holds it firmly. In the same way, it is preferable to reduce the pressure in the hold-down chamber 44, so that the hold-down 48 rests only on the components B without force. This situation is shown in the schematic representation of the number 2 overwritten FIG. 3 shown.

According to a preferred embodiment of the joining method, the pump 12 delivers a hydraulic volume flow of 23 L / min. In step S1 (cf. FIG. 3 ), this supplied by the pump 12 hydraulic volume flow to the Vorhubkammer 34 and the hold-down chamber 44 on. Therefore, preferably the Vorhubkammer 34 is supplied with a hydraulic volume flow of 9 L / min and the hold-down chamber 44 with a hydraulic flow rate of 14 L / min. Due to the diversion of displaced from the return stroke chamber 36 Hydraulic fluid in the Vorhubkammer 34 increases the piston 32 moving hydraulic flow rate to about 36 L / min.

It is likewise preferred to connect the return stroke chamber 36 to the tank 14 via the tank line 18 in step S2. In this way, the hydraulic pressure in the return stroke chamber 36 is largely reduced, since the hydraulic fluid displaced from the return stroke chamber 36 can flow into the tank 14 almost without resistance.

In step S3, a hydraulic pressure in the range of 0-100 bar is applied to the hold-down chamber 44 via the line 56. Depending on the selected hydraulic pressure, the hold-down device 48 fixes the components B differently or not at all. While in step S3, the return stroke chamber 36 is still connected to the tank 14 and thereby almost free of pressure, in the Vorhubkammer 34, a hydraulic pressure in the range of 50-250 bar is generated. Depending on the size of the area A _{1 of} the piston 32 results in the force with which the punch 38, the Hilfsfügeteil N, in the components B sets.

After the connection between the components B has been produced or the punch rivet N has been set in step S3, force is once again applied to the components B and the joint by the hold-down 48 alone or in combination with the punch 38. For this purpose, the hydraulic pressure in the prestroke chamber 34 and in the hold-down chamber 44 is simultaneously increased. According to another embodiment, the hydraulic pressure in the pre-stroke chamber 34 is reduced and the hydraulic pressure in the hold-down chamber 44 is increased to a value in the range of 50-100 bar. In this way, only the hold-down 48 in the region of the joint on a force.

According to step S4, it is also preferable to apply a force by increased hydraulic pressure in the hold-down chamber 44 through the hold-down 48 on the joint, while at the same time begins the return movement of the piston 32 with punch 38. For the return movement of the piston 32 with punch 38, the prestroke chamber 34 is connected to the tank 14 in order to ensure a displacement of the hydraulic fluid from the prestroke chamber 34 with low flow resistance. At the same time via the pump 12th a volume flow of hydraulic fluid into the port 54, ie in the return stroke 36. The introduced at a preferred pressure in the range of about 50 bar in the return stroke 36 hydraulic fluid moves the piston 32 with punch 38 against the setting direction of the components B away.

As soon as the punch 38 has reached a certain position during its movement counter to the setting direction, it tows the hold-down 48 via the mechanical coupling 39, for example an undercut in the punch 38. In order to provide the higher force required for this movement for the movement of piston 32 with plunger 38 and entrained hold-down 48, preferably the hydraulic pressure in the return stroke chamber 36 is increased to approximately 80-120 bar, preferably 100 bar.

The entrainment of the hold-48 and thus the plunger 42 through the plunger 38 displaces hydraulic fluid from the hold-down chamber 44. Preferably, the volume flow of the displaced from the hold-down chamber 34 hydraulic fluid is diverted into the return stroke chamber 36 by the terminals 54 and 56 are connected together. By connecting the return stroke chamber 36 and the hold-down chamber 44 with each other, the same hydraulic pressure in the return stroke chamber 36 and the hold-down chamber 44 is applied. Due to the larger area A ₂ at the bottom of the piston 32 compared to the surface of the plunger 42 results in a force that moves the piston 32 together with the plunger 42 opposite to the setting direction. In addition, the volume flow of the displaced from the hold-down chamber 44 hydraulic fluid in the return stroke chamber 36 supports the return movement of the piston 32 with punch 38 and entrained hold-48.

It is preferred that the pump 12 provide a volume flow of hydraulic fluid of 23 L / min for the return movement of the piston 32 with plunger 38. This volumetric flow provided by the pump 12 is supplemented by a volume flow of approximately 21 L / min of displaced hydraulic fluid from the hold-down chamber 44, so that a volume flow of hydraulic fluid of approximately 44 L / min resetting the piston 32 results. The increased volume flow of hydraulic fluid for the return the piston 32 and thus the punch 38 ensures a shortening of the cycle time of a joining operation.

After the piston 32 and the plunger 42 have reached their initial position in step S6, the hold-down chamber 44 is connected to the tank 14.

According to a further preferred embodiment of the joining method according to the invention is prevented after completion of the setting process, that in the hydraulic lines for supplying the Vorhubkammer 34 and / or the hold-down chamber 44 still remaining residual pressure in the hydraulic fluid completely degrades. Preferably, by means of a check valve which is arranged on the hydraulic unit 10 and a further valve in the valve block 20, the hydraulic fluid with a residual pressure of 30-200 bar, preferably 50-100 bar, enclosed in the pump tube 16. Since it is prevented that the residual hydraulic pressure in the pumping tube 16 is reduced, the energy stored in the pumping tube 16 in this way can be used in the pressurized hydraulic fluid for the following setting process. Thus, the pressurized and enclosed in the pumping tube 16 hydraulic volume at the beginning of the step S1 in the Vorhubkammer 34 and / or the hold-down chamber 44 is preferably released. This targeted release of the hydraulic volume with residual pressure from the pump hose 16 generates an accelerated feed movement of the piston 32 in the setting direction. As a result, on the one hand, residual energy from the completed setting process is stored and, on the other hand, this energy is used via the introduction of the hydraulic fluid under residual pressure in step S1 for accelerated delivery of punch 38 and / or hold-down 48. This accelerated delivery of punch 38 and / or hold-down 48 in turn leads to a shortening of the cycle time in comparison to the operation of the setting device S without the supply of trapped under residual pressure volume of hydraulic fluid.

Claims (15)

1. A hydraulically operated setting device (S) with a hydraulic aggregate (10) for establishing a connection between at least two components (B), in particular a rivet setting device, which comprises the following features:

   a. the hydraulic aggregate (10) with

   a1. a tank (14) for hydraulic fluid,

   a2. a pump (12) for pumping the hydraulic fluid to the setting device (S),

   a3. at least one pump hose (16), which connects the tank (14) via the pump (12) and a valve block (20) with the setting device (S), and at least one tank hose (18), which connects the tank (14) with the setting device (S) via the valve block (20),

   b. a double-acting cylinder (30) with a prestroke chamber (34) and a return-stroke chamber (36), in which the piston (32) with piston rod is moveably arranged, which moves a punch (38) of the setting device (S),

   c. a single-acting cylinder (40) with a hold-down device chamber (44), in which a plunge piston (42) is moveably arranged, which moves a hold-down device (48), characterized in that

   d. the valve block (20) comprises a plurality of valves, via which the return-stroke chamber (36) is connectable with the pump (12) and the hold-down device chamber (44) so that a volume flow of the hydraulic fluid out of the hold-down device chamber (44) supports a reset movement of the piston (32) and via which the prestroke chamber (34) and the hold down device chamber (44) are connectable to the pump (12) and the return-stroke chamber (36) so that a volume flow of the hydraulic fluid from the return stroke chamber (36) supports the movement of the piston (32) and the punch (38) as well as the hold-down device (48) in setting direction.
2. The hydraulically operated setting device (S) according to claim 1, in which the valve block (20) is arranged next to the setting device (S) so that the pump hose (16) and the tank hose (18) have a length of 5-30 m, preferably 8-22 m, between the tank (14) and the valve block (20).
3. The hydraulically operated setting device (S) according to claim 1 or 2, in which the valve block (20) is connected with at least the prestroke (34), the return-stroke (36) and the hold-down device chamber (44) via a plurality of hoses, each of which have a length of 0.15-6 m, preferably 0.3 to 3 m.
4. The hydraulically operated setting device (8) according to one of the previous claims, in which the hold-down device (48) is mechanically coupled with the punch (38) such that the punch (38) carries along the hold-down device (48) upon a movement opposite to a setting direction and/or the hold-down device (48) carries along the punch (38) upon a movement in the setting direction.
5. The hydraulically operated setting device (S) according to one of the previous claims, the piston (32) of which has a surface ratio between the piston surface (A₁) without and (A₂) with the piston rod of 1.1 ≤ Φ ≤ 1.8.
6. The hydraulically operated setting device (S) according to one of the previous claims, the piston (32) of which has a surface ratio between the piston surface (A₂) with the piston rod and the piston surface of the plunge piston (42) of 1.5 ≤ Φ ≤ 5.
7. The hydraulically operated setting device (S) according to one of the previous claims, the valve block (20) of which has at least two pressure sensors, with which a pressure is detectable in each of the prestroke chamber (34) and the hold-down device chamber (44).
8. The hydraulically operated setting device (S) according to one of the previous claims, the valve block (20) of which is designed as a stress relief component for the setting device (S) with respect to the connected pump hose (16) and the connected tank hose (18).
9. The hydraulically operated setting device (S) according to one of the previous claims in combination with claim 1, the valve block (20) of which is integrated into a cylinder arrangement consisting of the double-acting cylinder (30) and the single-acting cylinder (40), so that no hoses are required between the valve block (20) and the prestroke (34), the return-stroke (36) and the hold-down device chamber (44).
10. Joining method for connecting at least two components (B), in particular a setting method for a punch rivet (N), by means of a hydraulically operated setting device (S) with a hydraulic aggregate (10), which has the following features: the hydraulic aggregate (10) with a tank (14) for hydraulic fluid, a pump (12) for pumping the hydraulic fluid to the setting device (S), at least one pump hose (16), which connects the tank (14) with the setting device (S) via the pump (12) and a valve block (20), and at least one tank hose (18), which connects the tank (14) with the setting device (S) via the valve block (20), a double-acting cylinder (30) with a prestroke chamber (34) and a return-stroke chamber (36), in which the piston (32) with the piston rod is moveably arranged in order to drive the punch (38), a single-acting cylinder (40) with a hold-down device chamber (44), in which a plunge piston (42) is moveably arranged in order to drive the hold-down device (48), characterized in that the valve block (20) comprises a plurality of valves, via which the return-stroke chamber (36) can be connected with the pump (12) and the hold-down device chamber (44), wherein the setting method comprises the following steps:

    a) introducing a first hydraulic volume flow of the hydraulic fluid into the prestroke chamber (34) and the hold-down device chamber (44) so that the piston (32) with the punch (38) and the plunge piston (42) with hold-down device (48) are moved from an initial position in the setting direction (S1),

    b) connecting the return-stroke chamber (36) with the prestroke chamber (34) and the hold-down device chamber (44) in step a), so that a first hydraulic return flow of the hydraulic fluid is diverted out of the return-stroke chamber (36) into the prestroke chamber (34) and/or the hold-down device chamber (44) (S1, S2),

    c) increasing the hydraulic pressure in the prestroke chamber (34) after the hold-down device (48) and the punch (38) contact a component (B) to be connected, and establising a connection by setting the fastening element (N) into the component (B) or deforming the component (B) (S3),

    d) introducing a second hydraulic volume flow of the hydraulic fluid into the return-stroke chamber (36) so that the piston (32) is moved in the direction of the initial position (S4), and

    e) connecting the hold-down device chamber (44) with the return-stroke chamber (36) in step d) so that a second hydraulic return flow of the hydraulic fluid is diverted out of the hold-down device chamber (44) into the return-stroke chamber (36) and supports the movement of the piston (32) into the initial position (S5).
11. The joining method according to claim 10, which comprises the further step:
    carrying along the plunge piston (42) with hold-down device (48) by the piston (32) with piston rod and punch (38) when the piston (32) moves back into its initial position.
12. The joining method according to claim 11, wherein step e) is started as soon as the carrying along of the plunge piston (42) with the hold-down device (48) takes place and the plunge piston (42) displaces hydraulic fluid out of the hold-down device chamber (44).
13. The joining method according to one of claims 10-12, which has the further step:

    before the start of step a) creating an overpressure hydraulic volume in the pump hose (16) under increased pressure compared to a hydraulic pressure in the pump hose (16) during the movement of the punch (38) and hold-down device (48) in step a) and

    releasing the overpressure hydraulic volume at the start of step a) so that the movement of the piston with the punch (38) and of the plunge piston (42) with the hold-down device (48) is accelerated.
14. The joining method according to claim 10, in which the hydraulic volume in the pump hose (16) after completed setting procedure under increased pressure in the pump hose (16) is sealed between valves in order to create the overpressure hydraulic volume.
15. The joining method according to one of claims 10-14, which comprises the further step:
    heating the hydraulic fluid and the components of the circulation of the hydraulic fluid, in particular of the valve block (20), the valves, the hoses (16, 18), to an operating temperature, in which the hydraulic fluid is pumped into the tank (14) via the pump hose (16), a pressure relief valve in the valve block (20) and the tank hose (18) and is heated by a pressure increase before and a pressure release after the pressure relief valve.

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