Riveting Tool for High-strength Ring Groove Rivet

Abstract

A high-strength ring groove rivet includes a gun head assembly, a driving mechanism, a transmission mechanism, a power source and a control module arranged in a riveting tool shell. The transmission mechanism has a planetary roller lead screw shaft in coaxial driving connection with the clamping jaw of the gun head assembly, and is also in driving connection with the driving shaft of the driving mechanism through gears installed on the planetary roller lead screw shaft and the driving shaft of the driving mechanism respectively. The planetary roller lead screw is adopted as a component for converting rotary motion into linear motion, the output tension can reach 70 kN, and riveting installation of ring groove rivets with the diameter specification of 12 mm can be effectively completed.

Claims

1. A riveting tool for a high-strength ring groove rivet, comprising a gun head assembly, a driving mechanism, a transmission mechanism, a power source and a control module which are arranged in a riveting tool shell, wherein the gun head assembly comprises a clamping jaw and an anvil for squeezed riveting of a ring groove rivet; the power source is a detachable and rechargeable battery; the driving mechanism comprises a DC motor, a reduction gearbox driven by the DC motor, and a driving shaft; the transmission mechanism is a planetary roller lead screw transmission mechanism, a planetary roller lead screw shaft of the planetary roller lead screw transmission mechanism is in coaxial driving connection with the clamping jaw of the gun head assembly, and the planetary roller lead screw shaft is in driving connection with the driving shaft of the driving mechanism through gears installed on the planetary roller lead screw shaft and the driving shaft of the driving mechanism respectively.

2. The riveting tool for a high-strength ring groove rivet according to claim 1, wherein the planetary roller lead screw shaft is driven parallel to the driving shaft.

3. The riveting tool for a high-strength ring groove rivet according to claim 2, wherein the transmission mechanism further comprises a planetary roller lead screw nut which is in driving fit with the planetary roller lead screw shaft, and a large gear is sleeved on the periphery of the planetary roller lead screw nut; the diameter of a pinion sleeved on the driving shaft of the driving mechanism is smaller than that of a large gear, and the pinion sleeved on the driving shaft is in driving connection with the large gear sleeved on the planetary roller lead screw nut.

4. The riveting tool for a high-strength ring groove rivet according to claim 3, wherein a planar thrust roller bearing is arranged on a front end face of the planetary roller lead screw nut, a needle roller thrust bearing is arranged on a rear end face, and a set of needle roller bearings is arranged before and behind the periphery respectively.

5. The riveting tool for a high-strength ring groove rivet according to claim 3, wherein a set of needle roller bearings is arranged before and behind the periphery of the driving shaft respectively.

6. The riveting tool for a high-strength ring groove rivet according to claim 1, wherein the control module comprises: an STM32 main controller circuit, a current sampling circuit, a brushless DC motor drive circuit, a Hall stroke protection circuit, an overcurrent protection circuit, a Hall limit circuit, and a blocking protection circuit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a structural diagram of the riveting tool of the present utility model;

[0018] FIG. 2 is a partially enlarged schematic diagram of FIG. 1;

[0019] FIGS. 3 to 6 are schematic diagrams of the process of riveting a short tail type ring groove rivet;

[0020] FIGS. 7 to 10 are schematic diagrams of the process of riveting a breakaway type ring groove rivet.

[0021] In the figure, 1-clamping jaw, 2-anvil, 3-outer sleeve, 4-connecting shaft, 5-left end cover, 6-base, 7-steel ring, 8-needle roller bearing, 9-large gear, 10-needle roller bearing, 11-right end cover, 12-needle roller thrust bearing, 13-motor drive circuit board, 14-cooling fan, 15-steel ring, 16-LCD screen, 17-key, 18-motor, 19-control circuit board, 20-lithium battery, 21-switch, 22-reduction gearbox, 23-button battery, 24-pinion, 25-LED light, 26-needle roller bearing, 27-planetary roller lead screw nut, 28-planar thrust roller bearing, 29-planetary roller lead screw shaft, F-tension.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present utility model will be further described below in conjunction with the detailed description. The detailed description is a further explanation of the principle of the present utility model, and does not limit the present utility model in any way. The same or similar technology as the present utility model does not exceed the scope of protection of the present utility model.

[0023] Refer to the figures.

[0024] The riveting tool for a high-strength ring groove rivet in the present utility model is driven by its own battery, comprising a gun head assembly, a driving mechanism, a transmission mechanism, a power source, etc.

[0025] The gun head assembly comprises a clamping jaw 1 and an anvil 2; the anvil 2 is fixed with a gun body outer sleeve 3, and the clamping jaw 1 is in transmission connection with the transmission mechanism. The power source can be provided by a rechargeable lithium battery 20.

[0026] The driving mechanism is a reduction motor 18 driven by the rechargeable lithium battery 20. The transmission mechanism is a planetary roller lead screw transmission mechanism. The reduction motor 18 drives the planetary roller lead screw nut 27 to rotate through gear transmission, resulting in axial linear motion of the planetary roller lead screw shaft 29 to generate tension or thrust.

[0027] The present utility model adopts the planetary roller lead screw as a component for converting rotary motion into linear motion; the planetary roller lead screw is used in design of handheld lithium battery riveting tools, and the riveting force is adjusted using a current control program.

[0028] Compared to the ball screw drive used in electric tools, the ball screw and lead screw nut are in point contact; in the riveting tool of the present utility model, the planetary roller lead screw shaft 29 is in line contact with the lead screw nut 27, and line contact has better stress than point contact; for two types of lead screws with the same diameter specification, the planetary roller lead screw can theoretically achieve three times the load capacity and six times the service life of ordinary ball screws. In the design of high tension electric riveting tools, using planetary roller lead screws with smaller diameter specifications in the present utility model can meet the design requirements and effectively reduce the weight of the entire machine.

[0029] The tool is provided with a man-machine interaction interface, so that riveting parameters can be set through the interface, such as current, riveting stroke.

[0030] The control module of the present utility model comprises an STM32 main controller circuit, a current sampling circuit, a brushless DC motor drive circuit, a Hall stroke protection circuit, an overcurrent protection circuit, a Hall limit circuit, and a blocking protection circuit.

[0031] The present utility model can achieve riveting control based on the riveting principles and riveting characteristics of different rivets.

[0032] As shown in FIGS. 3 to 6, in response to the fluctuation and low accuracy of the current collection circuit during the operation of the motor, as well as the riveting characteristics of short tail type ring groove rivets, the riveting tool in the present utility model is used to set a current value Ia and a time t in the riveting control of short tail type ring groove rivets. For example, for 12 mm rivet riveting, the current value Ia is set to 27 A and the time t is 0.8 s; the current sampling circuit outputs the collected current value Ib to the MCU main controller. When Ia>Ib, the motor is controlled to continue running at a constant power for t time. After the time is reached, the motor starts to brake and reverse, thus achieving precise riveting control. Compared to the direct control stroke method, the advantage of the riveting tool in the present utility model is that: it can determine whether the anvil is too worn based on the riveting effect, or whether the rivets are qualified.

[0033] As shown in FIGS. 7 to 10, for the breakaway type ring groove rivets, due to their different riveting compositions and characteristics, the current change curves presented by the breakaway type ring groove rivets are different. The current is a discrete variation, and when broken away, its current value decreases instantly. Therefore, based on the change in current value, it can be determined whether the rivet is pulled apart, thereby achieving the goal of quickly controlling the motor brake reversal and achieving automatic reversal after breaking away.

[0034] The working process of the riveting tool in the present utility model is: after pressing the start switch 21, the motor 18 is powered on and starts running, and the torque is increased through the deceleration of the gearbox 22. The planetary roller lead screw nut 27 is installed with a large gear 9, which is meshed with the pinion 24 on the gearbox 22 shaft to further reduce the speed and increase the torque of the lead screw nut 27. The pinion 24 rotates to drive the large gear 9 to rotate and drive the planetary roller lead screw nut 27 to rotate. The rotational motion is converted into a linear motion of the planetary roller lead screw shaft 29 through the planetary roller lead screw, resulting in a tension on the clamping jaw 1. This tension acts on the ring groove rivet, and the forces act on each other, causing the anvil 2 on the gun head to generate thrust and squeeze the collar for deformation. When the system detects that the current of motor 18 has reached the preset value, the control module sends a signal and starts timing until the preset conditions in the program are met, and then the motor 18 brakes and reverses to the initial state, completing a riveting cycle.

[0035] Before using the riveting tool, the lithium battery 20 is installed on the base of the electric riveting tool, and then a program is selected on the parameter setting page according to the rivets to be installed. The switch 21 is pressed to install the ring groove rivets.

[0036] When performing riveting operations, the corresponding riveting mode is selected first according to different rivets using the key 17; the clamping jaw 1 is inserted into the tail part of the rivet, so that the pull trough inside the clamping jaw 1 is engaged with that at the tail part of the rivet; the switch 21 button is pressed, and then the motor 18 is powered on and starts running; upon power transmission by the driving mechanism and the transmission mechanism, the planetary roller lead screw shaft generates a tension F in the direction indicated by the arrow; the planetary roller lead screw shaft 29 is in threaded connection with the connecting shaft 4, and the other end of the connecting shaft 4 is connected with the clamping jaw 1. During this process, when the clamping jaw 1 is engaged and pulls the rivet tail and moves upwards, the anvil 2 presses against the outer edge of the collar, causing it to move in the opposite direction to clamping jaw 1 and squeeze the surface of the collar. In the process of squeezing the collar, the force required by the anvil 2 to squeeze the collar and achieve a certain deformation is the riveting force, which is equal to the tension generated by the planetary roller lead screw shaft 29. The riveting force changes in real time and gradually increases. The current of the motor 18 during the riveting process is detected by the current detection sensor on the motor driving circuit board 13, and the detected current value is fed back to the PLC program for data judgment. When the detected current value I or time t meets the set riveting mode, the motor immediately brakes and reverses. The downward movement of the planetary roller lead screw shaft 29 causes the clamping jaw 1 to push the rivet away from the jaw head 1, while the anvil 2 is also detached from the collar, thus completing the installation of the rivet.