Device for applying an applied force to a connection element

Abstract

The application relates to a device for applying an applied force to a connection element such that the connection element is plastically deformed by the application of force. The device comprises a movably mounted head part with a machining head which is designed to contact the connection element; a drive which is designed to drive a translation of the head part in the longitudinal axis thereof; a second drive which is designed to drive a rotation of the machining head about a longitudinal axis; and a housing for receiving the first drive, the second drive, and the head part. The first drive and the second drive are electrically driven and are arranged coaxially. The application further relates to a method for operating a device according to the application and to the use of a device according to the application as an electric riveting machine.

Claims

1. A device for acting on a connection element with an applied force, such that the connection element is plastically deformed by the application, comprising: a. a movably mounted head part comprising a machining head designed as a punch or rolling element for rolling forming, wherein the machining head is adapted to contact the connection element; b. a first drive adapted to drive a translation of the head part in the longitudinal axis of the head part, to drive it so that the applied force is applied to the connection element from the machining head; c. a second drive adapted to drive a rotation of the machining head about the longitudinal axis, and to drive the machining head so that the punch is able to describe at least one closed curve; d. a housing for accommodating the first drive, the second drive, and the head part; and wherein the first drive and the second drive each comprises an electrically driven motor and the electrically driven motors are coaxially arranged, and the second drive is arranged in the head part.

2. The device according to claim 1, wherein the motor of the first drive comprises a hollow shaft motor, and also comprises a screw drive selected from the group consisting of: roller drives, ball drives, or planetary screw drives.

3. The device according to claim 2, wherein the motor of the first drive comprises a threaded spindle having a spindle pitch of 5 mm or less.

4. The device according to claim 1, wherein the motor of the second drive comprises a permanently excited synchronous motor.

5. The device according to claim 1, wherein the device comprises a force sensor which measures the applied force and is connected downstream of the motor of the first drive, wherein the force sensor is connected upstream of the motor of the second drive.

6. The device according to claim 1, wherein the housing comprises a guide for a translational movement of the head part and wherein the housing comprises a rotation prevention with respect to the head part so that a translational movement of the head part within the housing is guided, but a rotation of the head part is prevented.

7. The device according to claim 6, wherein the rotation prevention and/or the guide are formed by at least one rod extending in the longitudinal direction through the housing and at least one step bearing for bearing the rotation prevention and/or the guide.

8. The device according to claim 1, comprising a cable guide integrated into the housing, and the cable guide is integrated into a spring coil in the housing, for conducting electrical signals between the head part and a connector.

9. The device according to claim 1, wherein the housing comprises a plurality of parts, wherein the housing comprises a first housing part and a second housing part, and wherein the housing parts are designed as detachably connectable to one another, so that a second housing part, which accommodates the second drive and the head part, is replaceable.

10. The device according to claim 1, further comprising at least one sensor for detecting a connection element.

11. A use of a device according to claim 1, as an electric riveting machine for applying force in a shape-changing way and deforming the connection elements to produce riveted connections, for applying force in a tumbling and/or radial fashion and deforming the connection element in order to produce riveted connections.

12. A method for operating the device according to claim 1, wherein a machine tool transmits control signals and electrical current to the device, comprising the steps: a. lowering the head part into an operative connection with a connection element; b. driving the machining head to execute a circular movement; c. driving the machining head to execute a translational force-applying movement, as a working stroke.

13. The method according to claim 12, wherein a connection element is detected by means of a tactile sensor and as a function of the detected connection element, the parameters for the application of force are selected and adapted based on feedback.

14. A machine tool comprising the device according to claim 1 and a fastening unit that is detachably connectable to the device in order to affix the device in a machine tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings used to explain the invention schematically depict the following:

(2) FIG. 1a shows an external view of a device according to the invention;

(3) FIG. 1b shows the device from FIG. 1a in an extended stroke;

(4) FIG. 2a shows a longitudinal cross-section through a device according to the invention;

(5) FIG. 2b shows the longitudinal cross-section from FIG. 2a in an extended stroke;

(6) FIG. 3 shows the rotation prevention of the device according to the invention;

(7) FIG. 4 shows a general schematic design of a concept according to the invention;

(8) FIG. 5 shows a particular embodiment with overload protections.

(9) The simplest embodiment of the invention is illustrated in the simplest way in FIG. 4. The device 1 according to the invention shown in FIG. 4 has the form of a cylinder with a longitudinal span and a longitudinal axis L, which also essentially constitutes the central axis of rotation. The outer structure is formed by a housing 3, 4, which is designed as a sleeve. The housing 3, 4 is advantageously composed of aluminum. At its proximal end, the housing 3, 4 has at least one opening through which a connection 2 extends, which is used to transmit electrical signals of a machine tool to the interior of the device 1. Starting from this proximal end, on the interior of the housing 3, 4, a first linear drive 13 is positioned, which is rigidly mounted in the housing 3, 4. This linear drive 13 is designed to permit a movement along the longitudinal axis of a piston or spindle. This activates a head part 16, which, in a fully retracted state of the stroke of the linear drive 13, is almost completely enclosed by the sleeve of the housing 3, 4. A bearing 15 supports the head part 16 so that it is able to move in relation to the housing 3, 4 in a translational fashion relative to the longitudinal axis L. Preferably, however, the head part 16 is rotationally fixed, i.e. is fixed relative to a rotation about the longitudinal axis L. Inside the head part 16, a second drive 8 is provided, which is designed as a rotary drive. This second drive 8 activates a connecting pin 8.4, which is able to execute a circular movement about the longitudinal axis. This connecting pin 8.4 can be operatively connected to a machining head 7 for machining the connection element.

(10) In this embodiment, both the first drive 13 and the second drive 8 are designed without pneumatic or hydraulic drives. In addition, the two drives 8, 13 are arranged coaxial to the longitudinal axis L of the device 1.

(11) This simple arrangement achieves a device 1 for acting on a connection element by means of the punch, which device is compact and permits it to be used in a room with increased cleanliness requirements.

(12) The machining head can be designed as a punch. The punch is then preferably composed of a material that is harder than the connection element that is to be machined, for example hardened tool steel. It has proven useful to use a punch made of steel. Depending on the field of application, this punch can also be provided with additional coatings that improve its abrasion resistance and wear resistance. Customarily, diamond compounds and ceramics are particularly suitable for such purposes.

(13) The compact design is also clearly shown in FIGS. 1a and 1b. These figures show a device 1 according to the invention in a retracted state (FIG. 1a) and in a state with a fully extended stroke (FIG. 1b). In this specific embodiment, the housing 3, 4 is composed of two parts. A first sleeve-shaped housing part 3 has the openings through which the connections 2 for the power and signal supply extend. This first housing part 3 is connected, for example by means of a bayonet connector, to a second housing part 4, which feeds into an orifice 4.1. In one embodiment, the second housing part 4 is screwed to the 3.

(14) FIG. 1b with the fully extended stroke shows the head part housing 5 and the head part orifice 5.1. Inside this head part orifice 5.1, the machining head, e.g. a punch (not shown), is mounted, which acts on the connection element. During operation, this head part orifice 5.1 is placed over the connection element that is to be machined. In a particular embodiment, (not shown) this orifice can also be designed with sensor elements, which detects the dimensions of the connection element both when force is not being applied to it and when force is being applied to it. For example, this orifice can be designed with a capacitive sensor or Hall sensor. The device can, however, also simply be equipped with a force sensor.

(15) The interior of the devices 1 shown in FIGS. 1a and 1b is shown in FIGS. 2a and 2b, respectively in the retracted state (FIG. 2a) and the extended state (FIG. 2b). The two housing part 3, 4 are designed as sleeve-shaped and are connected to each other. At the distal end, the first housing part has an opening through which the connections 2 are routed, which open into a cable guide 2.1 on the interior for supplying electrical power to the drives and sensors of the devices 1. In the present example, the connection 2 is sheathed in order to better withstand the conditions in a machine tool. The connection 2 can also be adapted to required standards in order to be accommodated in a corresponding robot. In the present example, the first drive 13 is a hollow shaft drive. Inside the hollow shaft 13.1, a spindle 13.4 is provided, around which is placed an arrangement of a rotor 13.3 and stator 13.2, which enclose a hollow shaft 13.5. The spindle is guided by a threaded nut 13.6 and leads directly to a pressure sensor 10, which in turn is operatively connected to the head part housing 5. The rotary drive shaft 8.2 is operatively connected to the machining head 7 by means of a rotary mechanism 8.1. In the present example, the machining head 7 is designed as a riveting machine punch and essentially includes a punch 7.2 and a head part shaft 7.1. The punch is driven such that it is able to execute a circular movement about the longitudinal axis L by means of the rotary mechanism 8.1. In this depiction, this is insured by the connecting pin for the machining head 8.4, which is depicted in offset fashion relative to the longitudinal axis and is able to rotate about the latter. The rotary drive shaft 8.2 and the spindle of the first drive 13.4 are arranged coaxially along the longitudinal axis of the tool. A head part orifice 5.1 protects the machining head 7 and facilitates the guidance of the device to the connection element, which is to be machined. A sealing lip 6 is mounted between the head part 5 and the second housing half 4 that encompasses the head part. The routing of the electrical lines is accommodated entirely inside the housing 3, 4. In order to accommodate the corresponding translation of the head part, the cable guide is designed as a cable guide spring coil 12. In order to prevent a rotation by means of the second drive 8 inside the housing 3, 4 from being transmitted to the first drive 13, rods 9 are positioned in rod shafts, which are supported in a rotation preventer with a step bearing 11 in a rotationally fixed manner relative to the longitudinal axis of the device 1.

(16) The machining head 7 does not have to be composed of two parts. In the present case, a head part shaft 7.1 is designed with a bushing to accommodate a connecting pin of the machining head 8.4.

(17) In FIGS. 2a and 2b, a transmission gearing 8.3 is positioned between the rotary drive 8 and the rotary mechanism 8.1. This transmission gearing can be used to reduce the rotation speed of the rotary drive, e.g. if the machining head 7 is a rolling head (not shown). This transmission gearing is optional and is not necessary for the arrangement with a punch 7.2 as the machining head 7.

(18) The embodiment of the rotation prevention will be explained once again in greater detail based on FIG. 3, which shows a schematic, perspective view of the second housing part 4 with the orifice 4.1 (bottom). The rods 9 extend over a significant part of the second housing part 4, which is equipped with an additional rotation preventer with a step bearing 11, which is accommodated in a rotationally fixed manner in the second housing part 4. The screws 14 of the head part extend across the entire connection site between the second housing part 4 and the first housing part (not shown in this depiction) and connect them in a rotationally fixed manner.

(19) FIG. 5 illustrates a device 1 according to the invention that is analogous to the one from FIG. 4, but which has additional advantageous embodiments. At its proximal end along the central axis of rotation L of the device 1, the aluminum housing 3.4 has an opening through which a manual rotation device 18 can be used to exert a manual rotation force directly on the shaft and the first linear drive 13. This device 1 also has overload protections 17.1, 17.2, which are positioned between the housing 3.4 and the first drive 13. A first overload protection is formed at the proximal end of the housing 3.4 in the form of a spring arrangement 17.1, which limit any forces that act on the first drive 13 with regard to its translational movement relative to the proximal end of the housing 3.4. A second overload protection in such a second spring arrangement 17.2 is likewise operatively connected—by means of tabs on the inside of the housing 3.4 (which can be an integral component of the housing 3.4)—to the drive 13 such that a translational force that acts on the drive 13 is likewise limited by this spring arrangement 17.2. The two overload protections 17.1, 17.2 protect the linear drive 13 from forces, thus increasing the ruggedness of the device. This embodiment, however, is entirely optional and is provided as a supplemental modification of the device according to the invention 1.

(20) It goes without saying that the example shown is merely one embodiment of the attainment of the object according to the invention. If the individual embodiments are not mutually exclusive, then they can be united in any combination in a devices according to the invention without limiting the advantages of the present invention by doing so.

REFERENCE NUMERAL LIST

(21) 1 device 2 connection 2.1 cable guide 3 first housing part 4 second housing part 4.1 orifice 5 head part housing 5.1 head part orifice 6 sealing lip 7 machining head 7.1 head part shaft 7.2 punch 8 rotary drive 8.1 rotary mechanism 8.2 rotary drive shaft 8.3 transmission gearing 8.4 connecting pin for the machining head 9 rod 10 pressure sensor 11 rotation preventer with a step bearing 12 cable guide spring coil 13 first drive 13.1 hollow shaft 13.2 stator of the first drive 13.3 rotor of the first drive 13.4 spindle of the first drive 13.6 threaded nut 14 connecting screws 15 head part bearing 16 head part 17.1 downward overload protection 17.2 upward overload protection 18 manual lifting and turning device