Integrated handheld electric hydraulic riveting tool and riveting method

Abstract

The present invention discloses an integrated handheld electric hydraulic riveting tool and a riveting method. In the first aspect, the integrated handheld electric hydraulic riveting tool includes a riveting work head and a hydraulic pump assembly. The hydraulic pump assembly is connected to an oil tank, and the hydraulic pump assembly is connected to an electric drive unit. The electric drive unit is connected to a power supply and a control unit. The riveting work head, the oil tank, the electric drive unit, the power supply and the control unit are all installed on the hydraulic pump assembly; a crankshaft for directly driving the hydraulic pump assembly to operate is provided in the hydraulic pump assembly, and a motor whose output shaft is connected to the tail end of the crankshaft is provided in the electric drive unit. In the second aspect, a riveting method for an integrated handheld electric hydraulic riveting tool. The present invention uses batteries as energy sources and adopts a highly integrated hydraulic power unit to provide power to the work head. The riveting operation can be completed by a single person, which greatly reduces the cost of mobile operations and reduces the difficulty of high-altitude operations.

Description

Technical Field

[0001] The invention relates to the technical field of rivet assembly tools, and in particular to an integrated handheld electric hydraulic riveting tool and a riveting method. Background Art

[0002] Since the riveting process has the advantages of fast component connection operation speed, high component tightening force precision, and not easy to loosen, which are superior to conventional bolts, the application fields of large-size rivets are no longer limited to traditional fields such as trains, cars, and bridges. They also show better performance and prospects than bolts in new fields such as large steel structure buildings, solar power plants, and wind power plants. In new application fields, rivet assembly is more outdoor work, high-altitude work, and non-fixed workstation work. In order to solve the energy problem in the riveting process, the hydraulic pump station is placed on the ground during high-altitude work, and a long oil pipe is used to connect the riveting tool to the pump station; a generator is used to provide power for the hydraulic pump station during outdoor work; when encountering outdoor non-fixed workstation work (such as on-site riveting work at a solar power plant), the generator and hydraulic pump need to be placed on the truck, which moves continuously with the changes in the riveting station, and auxiliary personnel such as drivers, mechanics, and electricians are required to accompany them, which is costly. Due to the above-mentioned factors, the construction cost of rivets in new fields is relatively high, which affects the promotion and application of rivets in new fields.

[0003] It is known that currently large-sized rivets are mainly made by combining hydraulic pump stations with riveting tools, which are connected by hydraulic oil pipes in the middle. The hydraulic pump station is powered by AC or three-phase power supply and is mostly used in production operations at fixed stations. The second form is to use a motor to drive the screw (ball screw and planetary roller screw) to realize the conversion from rotational motion to linear motion. The combination of a larger screw and a high-power motor can also provide a larger axial force to meet the riveting requirements, but the combination of the motor and the screw is difficult to achieve a balance between power, speed, riveting force and volume; if the motor power is reduced while the riveting force is met, a mechanical structure with a large reduction ratio is required, and the riveting efficiency will be significantly reduced; when the efficiency is met, a higher-power motor is required, which will also increase the volume. Since the transmission conversion ratio (the ratio of linear motion speed to motor speed) from the rotational motion of the motor to the linear motion of the ball screw during the riveting process is a fixed value, both the idle stroke and the loaded stroke run at basically the same speed, and more energy is consumed in the reduction mechanism, and the battery energy utilization rate is low. Summary of the invention

[0004] The purpose of the present invention is to provide an integrated handheld electric hydraulic riveting tool and riveting method, which uses batteries as energy and adopts a highly integrated hydraulic power unit to provide power to the working head. The riveting operation can be completed by a single person, greatly reducing the cost of mobile operations and reducing the difficulty of high-altitude operations.

[0005] In order to solve the above technical problems, the present invention adopts the following solutions:

[0006] In a first aspect, an integrated handheld electric hydraulic riveting tool includes a riveting work head for performing a riveting action, and also includes a hydraulic pump assembly for conveying oil into the riveting work head to drive the riveting work head to perform the riveting action, the hydraulic pump assembly is connected to an oil tank for storing oil, the hydraulic pump assembly is connected to an electric drive unit for driving the hydraulic pump assembly to operate, the electric drive unit is connected to a power supply and a control unit, and the riveting work head, the oil tank, the electric drive unit, the power supply and the control unit are all mounted on the hydraulic pump assembly;

[0007] The hydraulic pump assembly is provided with a crankshaft for directly driving the hydraulic pump assembly to operate, the electric drive unit is provided with an output shaft of a motor connected to the tail end of the crankshaft; a battery is provided in the power supply and control unit;

[0008] The crankshaft includes a rotating body-shaped driving shaft, a connecting cavity for connecting with the output shaft of the motor is provided at the rear end of the driving shaft, a connecting key is provided between the side wall of the output shaft of the motor and the inner side wall of the connecting cavity, two cylindrical crankshaft sleeves are provided on the outer side wall of the middle section of the driving shaft, the crankshaft sleeves are connected to the driving shaft through a key, an inner hole eccentric to the outer cylindrical surface of the crankshaft sleeve is provided on the crankshaft sleeve, and a keyway for key connection with the driving shaft is provided on the inner side wall of the crankshaft sleeve in the opposite direction of the eccentricity of the inner hole, and the keyways with a difference of 180° are provided on the driving shaft, and after the two crankshaft sleeves are assembled on the driving shaft along the axial direction of the driving shaft, a combined crankshaft with an eccentric difference of 180° is formed, and bearings are provided on the outer side wall of the crankshaft sleeve and the journal at the head end of the driving shaft;

[0009] Its function is to make the riveting tools no longer rely on the hydraulic pump station powered by the mains or power supply as before through the setting of the power supply, control unit and oil tank, so that the riveting tools no longer need to be connected to a long oil pipe when working at high altitude, and the convenience and safety of operation are significantly improved; there is no need to equip the generator and separate hydraulic pump station for outdoor operation; there is no need to carry the generator and hydraulic pump station by the truck for mobile operation, nor is there a need to equip electricians, mechanics and other technical personnel as assistance. As the difficulty and construction cost of riveting operations are reduced, the application and promotion of riveting technology in steel structure construction, wind power, solar energy and other fields are promoted. Through the setting of the crankshaft, the conversion and transmission between motor drive and hydraulic transmission are realized, and a larger riveting force can be met with a smaller motor power, and the battery energy utilization rate is high.

[0010] Furthermore, the hydraulic pump assembly includes a main body, the main body is connected to at least one combined plunger pump body, at least one combined plunger pump body is connected to an oil tank, and the combined plunger pump body is provided with a plunger whose bottom end is used to contact the side wall of the crankshaft. Its function is that through the arrangement of the combined plunger pump body, the thrust of the crankshaft on the plunger can be converted into pressure on the oil, thereby driving the riveting work head to move.

[0011] Furthermore, the oil tank adopts a diaphragm oil tank, and an air bag connected to the atmosphere is arranged in the oil tank. The oil in the oil tank can maintain pressure balance with the atmosphere, so that the fluctuation of the oil amount in the oil tank generated by the reciprocating motion of the working head will not generate negative pressure to affect the system efficiency, and the atmosphere and oil are separated to ensure that the oil tank can supply oil to the hydraulic system normally in any posture of the tool, avoiding gas mixing in the hydraulic oil to cause cavitation, which affects the service life of the tool.

[0012] Furthermore, the combined plunger pump body has two symmetrically arranged on the left and right sides of the main body, an oil tank is arranged above one of the combined plunger pump bodies and is connected to the combined plunger pump body, and an oil delivery channel is provided in the main body to connect the oil tank with the combined plunger pump body located on the other side of the main body. The plungers of the two combined plunger pump bodies are relatively arranged on both sides of the crankshaft, and each combined plunger pump body is provided with two plungers corresponding to the two crankshaft sleeves respectively. Its function is that, through the design that the combined plunger pump bodies are symmetrically arranged on the left and right sides of the main body, the crankshaft pushes the plunger on the left side of the main body to pressurize the oil while the plunger on the right side of the main body is sucking the oil, so that the hydraulic transmission of the hydraulic pump assembly as a whole is smoother.

[0013] Furthermore, a crankshaft cavity for placing the crankshaft is provided in the main body, and the oil delivery channel is connected to the crankshaft cavity. When the crankshaft is installed in the crankshaft cavity, the crankshaft cavity is only connected to the oil delivery channel. Its function is that, through the setting of the oil delivery channel being connected to the crankshaft cavity, since the plunger and the combined plunger pump body are sealed by a metal gap, it is difficult to achieve a complete seal, and oil leakage will always occur, so the crankshaft cavity is connected to the oil tank, and at the same time, it plays a role in lubricating the bearings sleeved on the crankshaft in the crankshaft cavity.

[0014] Furthermore, a working head piston is provided in the riveting working head, and the main body is connected to an electromagnetic reversing valve for controlling the forward and backward movement of the working head piston. An anvil connected to the working head piston is provided in the riveting working head, and the anvil is in a hollow cylindrical shape. A claw for fixing the rivet is provided in the anvil, and the claw is fixed on the outer shell of the riveting working head. When the working head piston drives the anvil to move, the claw remains stationary.

[0015] Furthermore, the main body is provided with a first drive oil circuit and a second drive oil circuit for connecting the riveting working head and the electromagnetic reversing valve, and the riveting working head is provided with a piston chamber for the working piston head to move back and forth, the first drive oil circuit is connected to the front side of the piston chamber, and the second drive oil circuit is connected to the rear side of the piston chamber. Its function is that, through the setting of the first drive oil circuit and the second drive oil circuit, when one of the drive oil circuits is fed with oil, the other drive oil circuit is discharged with oil, and under the joint action of the first drive oil circuit and the second drive oil circuit, the working piston head is jointly driven to move.

[0016] Furthermore, a bypass valve is provided on the main body, and the combined plunger pump body is provided with a high-pressure oil outlet and a low-pressure oil outlet. A high-pressure oil circuit connecting the high-pressure oil outlet with the electromagnetic reversing valve and a low-pressure oil circuit connecting the low-pressure oil outlet with the bypass valve are provided in the main body. The electromagnetic reversing valve is connected to the oil delivery channel and the high-pressure oil circuit, the bypass valve is connected to the oil delivery channel, the low-pressure oil circuit and the high-pressure oil circuit, the high-pressure oil circuit is connected to the end face of the bypass valve core, and the bypass valve has a low-pressure state that cuts off the oil delivery channel and the low-pressure oil circuit and a high-pressure state that connects the oil delivery channel and the low-pressure oil circuit. Its function is to realize the switching of the hydraulic system state of the entire hydraulic pump assembly through the setting of the bypass valve. When the load of the riveting working head is small, the oil flowing out of the oil tank enters the riveting working head through the high-pressure oil circuit to push the working head piston to move. When the load of the riveting working head is large, the working piston head hinders the push of the oil, causing the hydraulic pressure in the high-pressure oil circuit to increase, thereby increasing the thrust of the oil in the high-pressure oil circuit on the valve core of the bypass valve, thereby pushing the valve core of the bypass valve to move, switching the state of the bypass valve, connecting the low-pressure oil circuit with the oil delivery channel, increasing the hydraulic pressure in the oil delivery channel, thereby increasing the hydraulic pressure in the high-pressure oil circuit, and increasing the thrust of the oil on the working head piston. Since the difference between the thrust of the oil on the working head piston and the resistance of the load to the movement of the working head piston is greater in the state of smaller load than that of larger load, the moving speed of the working head piston in the state of smaller load is greater than that of the working head piston in the state of larger load.

[0017] Furthermore, the main body is provided with a safety valve and a pressure sensor, the safety valve is connected with the oil delivery channel and the high-pressure oil circuit, and the pressure sensor is provided on the safety valve. Its function is to detect the pressure of the hydraulic system through the pressure sensor. When the valve or control system fails, the hydraulic system pressure reaches the safety valve limit pressure, the safety valve will open, so that the oil delivery channel is connected with the high-pressure oil circuit, and the maximum pressure of the system is limited to the pressure value set by the safety valve.

[0018] In a second aspect, a riveting method of an integrated handheld electric hydraulic riveting tool comprises the following steps:

[0019] S1. Align the riveting head with the rivet to prepare for riveting;

[0020] S2, start the power switch to make the output shaft of the motor rotate around its own axis;

[0021] S3, the output shaft of the motor drives the crankshaft to rotate around its own axis;

[0022] S4, the crankshaft drives the hydraulic pump assembly to drive the riveting work head to connect with the rivet to perform the riveting operation;

[0023] S5. After riveting is completed, remove the riveting head from the rivet.

[0024] Furthermore, the method further comprises the following steps:

[0025] S401, before the riveting operation, the electromagnetic reversing valve connects the high-pressure oil circuit with the second drive oil circuit and connects the oil delivery channel with the first drive oil circuit, the oil enters the combined plunger pump body from the oil tank through the oil delivery channel, flows out from the high-pressure oil outlet into the high-pressure oil circuit, and then enters the second drive oil circuit through the electromagnetic reversing valve, and the oil pushes the working head piston to move toward the outside of the riveting working head through the second drive oil circuit; S4a, during the riveting process, when the external load is small, the oil enters the combined plunger pump body from the oil tank through the oil delivery channel, flows out from the high-pressure oil outlet into the high-pressure oil circuit, and then enters the second drive oil circuit through the electromagnetic reversing valve, and the oil pushes the working head piston to move toward the outside of the riveting working head through the second drive oil circuit, and the original oil in the first drive oil circuit is sucked into the oil delivery channel by the negative pressure of the oil delivery channel on the first drive oil circuit, completing the riveting operation;

[0026] S4b. During the riveting process, when the external load is large, the pressure of the high-pressure oil circuit on the bypass valve increases, thereby pushing the valve core of the bypass valve to change the state of the bypass valve, so that the low-pressure oil circuit is connected with the oil delivery channel, and the oil enters the combined plunger pump body from the oil tank through the oil delivery channel. A part of it flows out from the high-pressure oil outlet into the high-pressure oil circuit, and the other part flows out from the low-pressure oil outlet into the low-pressure oil circuit and then flows into the oil delivery channel through the bypass valve. The oil after entering the high-pressure oil circuit enters the second drive oil circuit through the electromagnetic reversing valve. The oil pushes the working head piston to move toward the outside of the riveting working head through the second drive oil circuit. The original oil in the first drive oil circuit is sucked into the oil delivery channel by the negative pressure of the oil delivery channel on the first drive oil circuit, completing the riveting operation;

[0027] S4c. During the riveting process, the pressure of the hydraulic system is detected by the pressure sensor. When the valve or control system fails, the hydraulic system pressure reaches the limit pressure of the safety valve, and the safety valve will open to connect the oil delivery channel with the high-pressure oil circuit, limiting the maximum pressure of the system to the pressure value set by the safety valve;

[0028] S4e. During the riveting process, the control part in the power supply and control unit reads the parameters of the pressure sensor provided on the safety valve, calculates the actual riveting force and compares the actual riveting force with the preset riveting force. When the actual riveting force reaches the preset riveting force, the electromagnetic reversing valve is reversed to connect the high-pressure oil circuit with the first drive oil circuit and the oil delivery channel with the second drive oil circuit. The oil in the high-pressure oil circuit enters the first drive oil circuit through the electromagnetic reversing valve. The oil enters the piston cavity from the front side of the piston cavity to push the front end of the working head piston, so that the working head piston moves toward the riveting work head. The original oil in the second drive oil circuit is sucked into the oil delivery channel by the negative pressure of the oil delivery channel on the second drive oil circuit, thereby realizing the retraction operation of the riveting work head.

[0029] S5a. During the retraction process, the control part in the power supply and control unit reads the parameters of the pressure sensor on the safety valve, calculates the oil pressure of the high-pressure oil circuit when the riveting work head retracts, and compares the actual retraction oil pressure with the preset retraction pressure. When the actual retraction oil pressure reaches the preset retraction pressure, the control part in the power supply and control unit controls the motor to stop and the riveting is completed.

[0030] The present invention has the beneficial effects:

[0031] 1. Through the setting of power supply, control unit and oil tank, the riveting tools no longer rely on the hydraulic pump station powered by the mains or power supply as before, so that the riveting tools no longer need to be connected to long oil pipes when working at high altitudes, and the convenience and safety of operation are significantly improved; outdoor operations no longer need to be equipped with generators and separate hydraulic pump stations; mobile operations no longer need to be carried by trucks. Generators and hydraulic pump stations are also not required, and electricians, mechanics and other technical personnel are not required as auxiliary personnel. Since the difficulty and construction cost of riveting operations are reduced, the application and promotion of riveting technology in steel structure construction, wind power, solar energy and other fields are promoted;

[0032] 2. The setting of the crankshaft realizes the conversion and transmission between motor drive and hydraulic transmission, which can meet the larger riveting force with smaller motor power and has high battery energy utilization rate;

[0033] 3. By combining the setting of the plunger pump body, the thrust of the crankshaft on the plunger can be converted into pressure on the oil, thereby driving the riveting work head to move. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the three-dimensional assembly structure of the present invention;

[0035] Figure 2 It is a schematic diagram of the three-dimensional explosion structure of the present invention;

[0036] Figure 3It is a three-dimensional exploded structural schematic diagram of a hydraulic pump assembly equipped with an oil tank;

[0037] Figure 4 It is a schematic diagram of the cross-sectional structure of the riveting working head;

[0038] Figure 5 is a schematic diagram of a cross-sectional structure of a crankshaft;

[0039] Figure 6 is a schematic diagram of the cross-sectional structure of the fuel tank;

[0040] Figure 7 It is a schematic diagram of the cross-sectional structure of the bypass valve;

[0041] Figure 8 A schematic diagram of the three-dimensional structure of the main body;

[0042] Fig. 9 A schematic diagram of the three-dimensional structure of the subject from another perspective;

[0043] Fig.10 It is a schematic diagram of the working principle of the present invention;

[0044] Fig.11 This is a working state diagram of the riveting head and the rivet before riveting begins;

[0045] Fig.12 This is a diagram of the working status of the riveting head and the rivet during the riveting process.

[0046] The accompanying drawings are described as follows: 1. riveting working head; 2. hydraulic pump assembly; 3. oil tank; 4. electric drive unit; 5. power supply and control unit; 6. crankshaft; 7. output shaft; 8. combined plunger pump body; 9. plunger; 10. oil delivery channel; 11. crankshaft chamber; 12. working head piston; 13. electromagnetic reversing valve; 14. first drive oil circuit; 14a, first oil circuit; 15. second drive oil circuit; 15a, second oil circuit; 16. piston chamber; 17. bypass valve; 18. high-pressure oil outlet; 19. low-pressure oil outlet 1. Inlet; 20. High-pressure oil circuit; 21. Low-pressure oil circuit; 22. Safety valve; 23. Pressure sensor; 24. Main body; 25. Crankshaft sleeve; 26. Bearing; 27. Drive shaft; 28. Connecting chamber; 29. ​​Airbag; 30. Low-pressure oil port; 31. High-pressure control oil port; 32. Low-pressure bypass oil return port; 33. High-pressure valve core; 34. Bypass valve core; 35. High-pressure sealing retaining ring; 36. Compression spring; 37. High-pressure pump; 38. Low-pressure pump; 39. High-pressure pump oil pressure check valve; 40. Anvil; 41. Claw. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0048] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0049] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] Example 1

[0051] In a first aspect, an integrated handheld electric hydraulic riveting tool, such as Figure 1 , Figure 2 As shown, it includes a riveting work head 1 for performing riveting actions, and also includes a hydraulic pump assembly 2 for conveying oil into the riveting work head 1 to drive the riveting work head 1 to perform riveting actions, the hydraulic pump assembly 2 is connected to an oil tank 3 for storing oil, the hydraulic pump assembly 2 is connected to an electric drive unit 4 for driving the hydraulic pump assembly 2 to operate, the electric drive unit 4 is electrically connected to a power supply and a control unit 5, the riveting work head 1, the oil tank 3, the electric drive unit 4, the power supply and the control unit 5 are all installed on the hydraulic pump assembly 2, the battery and the control unit are arranged on the bottom surface of the hydraulic pump assembly 2, the electric drive unit 4 is arranged on the rear end surface of the hydraulic pump assembly 2, the oil tank 3 is arranged on the right side wall of the hydraulic pump assembly 2, and the riveting work head 1 is arranged on the front end surface of the hydraulic pump assembly 2;

[0052] Specifically, Figure 3 As shown, the hydraulic pump assembly 2 is provided with a crankshaft 6 for directly driving the hydraulic pump assembly 2 to operate, and the electric drive unit 4 is provided with an output shaft 7 of a motor connected to the tail end of the crankshaft 6;

[0053] The power supply and control unit 5 includes a battery, a main control board, a handle, a control button, and a solenoid valve drive board. The handle is arranged at the top of the battery, the main control board is arranged inside the handle, the control button is arranged on the handle housing, and the solenoid valve drive board is arranged above the handle;

[0054] The electric drive unit 4 includes a motor, a motor driver, a setting button, a display screen, and a sealing ring. The setting button and the display screen are arranged on the outer wall of the motor driver, and the sealing ring is arranged on the end surface of the electric drive unit 4 that contacts the crankshaft 6.

[0055] Specifically, Figure 5 As shown, the crankshaft 6 includes a rotating body-shaped driving shaft 27, a connecting cavity 28 for connecting with the output shaft 7 of the motor is provided at the rear end of the driving shaft 27, a connecting key is provided between the side wall of the output shaft 7 of the motor and the inner side wall of the connecting cavity 28, two cylindrical crankshaft eccentric sleeves 25 are provided on the outer side wall of the middle section of the driving shaft 27, the crankshaft eccentric sleeve 25 and the driving shaft 27 are connected by a key, the crankshaft eccentric sleeve 25 is provided with an inner hole eccentric to the outer cylindrical surface of the crankshaft eccentric sleeve 25, and the crankshaft eccentric sleeve 25 is provided with a keyway for key connection with the driving shaft 27 on the inner side wall in the opposite direction of the eccentricity of the inner hole, the driving shaft 27 is provided with keyways with a difference of 180°, and after the two crankshaft eccentric sleeves 25 are assembled on the driving shaft 27 along the axial direction of the driving shaft 27, a combined crankshaft 6 with an eccentric difference of 180° is formed, and bearings 26 are provided on the outer side wall of the crankshaft eccentric sleeve 25 and the journal at the head end of the driving shaft 27;

[0056] Its function is that, through the setting of the power supply and control unit 5 and the oil tank 3, the riveting tool no longer relies on the hydraulic pump station powered by the mains or power supply in the past, so that the riveting tool no longer needs to be connected to a long oil pipe during high-altitude operations, and the convenience and safety of operation are significantly improved; there is no need to equip a generator and a separate hydraulic pump station during outdoor operations; during mobile operations, there is no need for a truck to carry the generator and hydraulic pump station, nor is there a need to equip electricians, mechanics and other technical personnel as assistance. Since the difficulty and construction cost of riveting operations are reduced, the application and promotion of riveting technology in the fields of steel structure construction, wind power, solar energy, etc. are promoted. Through the setting of the crankshaft 6, the conversion and transmission between motor drive and hydraulic transmission are realized, and a larger riveting force can be met with a smaller motor power, and the battery energy utilization rate is high.

[0057] Specifically, Figure 3 As shown, the hydraulic pump assembly 2 includes a main body 24, the main body 24 is connected to at least one combined plunger pump body 8, at least one combined plunger pump body 8 is connected to an oil tank 3, and a plunger 9 is provided in the combined plunger pump body 8, the bottom end of which is used to contact the side wall of the crankshaft 6. Its function is that, through the arrangement of the combined plunger pump body 8, the thrust of the crankshaft 6 on the plunger 9 can be converted into pressure on the oil, thereby driving the riveting work head 1 to move.

[0058] Specifically, Figure 6As shown, the oil tank 3 adopts a diaphragm oil tank 3, and an air bag 29 connected to the atmosphere is arranged in the oil tank 3. The oil in the oil tank 3 can maintain pressure balance with the atmosphere, so that the oil amount fluctuation in the oil tank 3 generated when the working head reciprocates will not generate negative pressure to affect the system efficiency, and the atmosphere and the oil are separated, ensuring that the oil tank 3 can normally supply oil to the hydraulic system in any posture of the tool, avoiding gas mixing in the hydraulic oil to cause cavitation and affecting the service life of the tool.

[0059] Specifically, Figure 3 As shown, the combined plunger pump body 8 has two symmetrically arranged on the left and right sides of the main body 24, the oil tank 3 has one and is arranged above one of the combined plunger pump bodies 8 and is connected to the combined plunger pump body 8, and the main body 24 is provided with an oil delivery channel 10 that connects the oil tank 3 with the combined plunger pump body 8 located on the other side of the main body 24. The plungers 9 of the two combined plunger pump bodies 8 are relatively arranged on both sides of the crankshaft 6, and each combined plunger pump body 8 is provided with two plungers 9 corresponding to the two crankshaft 6 offset sleeves. Its function is that, through the design that the combined plunger pump body 8 is symmetrically arranged on the left and right sides of the main body 24, the crankshaft 6 pushes the plunger 9 on the left side of the main body 24 to pressurize the oil, while the plunger 9 on the right side of the main body 24 is just sucking the oil, so that the overall hydraulic transmission of the hydraulic pump assembly 2 is more stable.

[0060] Specifically, Figure 3 As shown, the main body 24 is provided with a crankshaft cavity 11 for placing the crankshaft 6, and the oil delivery channel 10 is connected to the crankshaft cavity 11. When the crankshaft 6 is installed in the crankshaft cavity 11, the crankshaft cavity 11 is only connected to the oil delivery channel 10. Its function is that, through the setting of the oil delivery channel 10 being connected to the crankshaft cavity 11, since the plunger 9 and the combined plunger pump body 8 are sealed by the metal gap, it is difficult to achieve a complete seal, and oil leakage will always occur, so the crankshaft cavity 11 is connected to the oil tank 3, and at the same time, it plays a role in lubricating the bearings sleeved on the crankshaft 6 in the crankshaft cavity 11.

[0061] Specifically, Figure 4 As shown, the riveting work head 1 is provided with a work head piston 12, and the main body 24 is connected to an electromagnetic reversing valve 13 for controlling the forward and backward movement of the work head piston 12. The riveting work head 1 is provided with an anvil 40 connected to the work head piston 12, and the anvil 40 is in a hollow cylindrical shape. The anvil 40 is provided with a claw 41 for fixing the rivet, and the claw 41 is fixed to the outer shell of the riveting work head 1. The rear end of the riveting work head 1 is threadedly connected with a work head cylinder cover, and the work head cylinder cover is threadedly connected to the claw, and the work head piston 12 is threadedly connected to the anvil 40. The anvil 20 and the claw 41 are coaxially arranged. In the process of the working head piston 12 driving the anvil 40 to move, the claw 41 is stationary.

[0062] Specifically, Figure 8 , Fig. 9 As shown, the main body 24 is provided with a first drive oil circuit 14 and a second drive oil circuit 15 for connecting the riveting work head 1 and the electromagnetic reversing valve 13, and the riveting work head 1 is provided with a piston chamber 16 for the working piston head to move back and forth, the first drive oil circuit 14 is connected to the front side of the piston chamber 16, and the second drive oil circuit 15 is connected to the rear side of the piston chamber 16. The front and rear ends of the working head piston 12 are chamfered to facilitate the oil to enter between the piston and the piston chamber 16 when the working head piston 12 contacts the inner end surface of the piston chamber 16. The riveting work head 1 is provided with a first oil circuit 14a connecting the front side of the piston chamber 16 with the first drive oil circuit 14 and a second oil circuit 15a connecting the rear side of the piston chamber 16 with the second drive oil circuit 15. Its function is that through the setting of the first drive oil circuit 14 and the second drive oil circuit 15, when one of the drive oil circuits is filled with oil, the other drive oil circuit is discharged with oil. Under the joint action of the first drive oil circuit 14 and the second drive oil circuit 15, the working piston head is driven to move.

[0063] Specifically, Figure 3 As shown, the main body 24 is provided with a bypass valve 17, the combined plunger pump body 8 is provided with a high-pressure oil outlet 18 and a low-pressure oil outlet 19, a high-pressure oil circuit 20 connecting the high-pressure oil outlet 18 with the electromagnetic reversing valve 13 and a low-pressure oil circuit 21 connecting the low-pressure oil outlet 19 with the bypass valve 17 are provided in the main body 24, the electromagnetic reversing valve 13 is connected to the oil delivery channel 10 and the high-pressure oil circuit 20, the bypass valve 17 is connected to the oil delivery channel 10, the low-pressure oil circuit 21, and the high-pressure oil circuit 20, the high-pressure oil circuit 20 is connected to the end face of the valve core of the bypass valve 17, and the bypass valve 17 has a low-pressure state that cuts off the oil delivery channel 10 and the low-pressure oil circuit 21 and a high-pressure state that connects the oil delivery channel 10 and the low-pressure oil circuit 21. Its function is to switch the hydraulic system state of the hydraulic pump assembly 2 as a whole through the setting of the bypass valve 17. When the load of the riveting work head 1 is small, the oil flowing out of the oil tank 3 enters the riveting work head 1 through the high-pressure oil circuit 20 to push the working head piston 12 to move. When the load of the riveting work head 1 is large, the working piston head hinders the push of the oil, so that the hydraulic pressure in the high-pressure oil circuit 20 increases, thereby increasing the thrust of the oil in the high-pressure oil circuit 20 on the valve core of the bypass valve 17, thereby pushing the valve of the bypass valve 17. The core moves, switching the state of the bypass valve 17, so that the low-pressure oil circuit 21 is connected with the oil delivery channel 10, increasing the hydraulic pressure in the oil delivery channel 10, thereby increasing the hydraulic pressure in the high-pressure oil circuit 20, and increasing the thrust of the oil on the working head piston 12. Due to the difference between the thrust of the oil on the working head piston 12 and the resistance of the load to the movement of the working head piston 12, the thrust of the oil on the working head piston 12 is greater than that of the load under the state of light load, so the movement speed of the working head piston 12 under the state of light load is greater than that of the work head piston 12 under the state of heavy load.

[0064] Specifically, Figure 7 As shown, the bypass valve 17 is provided with a low-pressure bypass oil return port 32 connected to the oil delivery channel 10, a low-pressure oil port 30 connected to the low-pressure oil circuit 21, and a high-pressure control oil port 31 connected to the high-pressure oil circuit 20. The high-pressure control oil port 31 is connected to a cavity provided with a high-pressure valve core 33. The end surface of the high-pressure valve core 33 can contact the end surface of the bypass valve core 34. The cavity where the high-pressure valve core 33 is located and the cavity where the bypass valve core 34 is located are separated by a high-pressure sealing retainer ring 35. A compression spring 36 is provided at one end of the bypass valve core 34 away from the high-pressure valve core 33. The low-pressure oil port 30 and the low-pressure bypass oil return port 32 are connected to the cavity where the bypass valve core 34 is located.

[0065] Specifically, Fig.10 As shown, the combined plunger pump body 8 is provided with a high-pressure pump 37 and a low-pressure pump 38, the high-pressure pump 37 is provided with a high-pressure pump plunger 9, the low-pressure pump 38 is provided with a low-pressure pump plunger 9, the low-pressure pump 38 is connected to the low-pressure oil outlet 19 through a low-pressure branch, the low-pressure branch is provided with a low-pressure branch check valve, the high-pressure pump 37 is connected to the low-pressure pump 38 and a low-pressure pump oil check valve is provided between the high-pressure pump 37 and the low-pressure pump 38, a high-pressure pump oil check valve 39 is provided between the high-pressure pump 37 and the high-pressure oil outlet 18, and the oil circuit between the low-pressure pump 38 and the high-pressure oil outlet 18 is called a high-pressure branch. Its function is that, under a large load state, since two check valves are provided in the high-pressure branch and only one check valve is provided in the low-pressure branch, the hydraulic pressure of the oil entering the high-pressure branch is greater than the hydraulic pressure of the oil entering the low-pressure branch, thereby increasing the hydraulic pressure of the oil entering the high-pressure branch.

[0066] Specifically, Figure 3 As shown, the main body 24 is provided with a safety valve 22 and a pressure sensor 23. The safety valve 22 is connected with the oil delivery channel 10 and the high-pressure oil circuit 20. The pressure sensor 23 is arranged on the safety valve 22. Its function is to detect the pressure of the hydraulic system through the pressure sensor 23. When the valve or control system fails, the hydraulic system pressure reaches the limit pressure of the safety valve 22, and the safety valve 22 will open to connect the oil delivery channel 10 with the high-pressure oil circuit 20, and limit the maximum pressure of the system to within the pressure value set by the safety valve 22.

[0067] In a second aspect, a riveting method of an integrated handheld electric hydraulic riveting tool comprises the following steps:

[0068] S1. Align the riveting head 1 with the rivet. Specifically, Fig.11 As shown, the tail section of the rivet is installed in the claw 4 so that it is in a riveting preparation state;

[0069] S2, start the power switch to make the output shaft 7 of the motor rotate around its own axis;

[0070] S3, the output shaft 7 of the motor drives the crankshaft 6 to rotate around its own axis;

[0071] S4, the crankshaft 6 drives the hydraulic pump assembly 2 to drive the riveting work head 1 to connect with the rivet and perform the riveting operation;

[0072] S5. After riveting is completed, the riveting work head 1 is removed from the rivet.

[0073] The following steps are also included:

[0074] S401. Before the riveting operation, the electromagnetic reversing valve 13 connects the high-pressure oil circuit 20 with the second drive oil circuit 15 and connects the oil delivery channel 10 with the first drive oil circuit 14. The oil enters the combined plunger pump body 8 from the oil tank 3 through the oil delivery channel 10, flows out from the high-pressure oil outlet 18 to the high-pressure oil circuit 20, and then enters the second drive oil circuit 15 through the electromagnetic reversing valve 13. The oil pushes the working head piston 12 to move toward the outside of the riveting working head 1 through the second drive oil circuit 15. Fig.12 As shown, the working head piston 12 drives the anvil 20 to move outside the riveting working head 1, and the end face of the anvil 40 squeezes the end face of the threaded sleeve threadedly connected to the outer wall of the middle section of the rivet, squeezing and deforming the threaded end face; S4a, during the riveting process, when the external load is small, the oil enters the combined plunger pump body 8 from the oil tank 3 through the oil delivery channel 10, flows out from the high-pressure oil outlet 18 to the high-pressure oil circuit 20, and then enters the second drive oil circuit 15 through the electromagnetic reversing valve 13. The oil pushes the working head piston 12 to move outside the riveting working head 1 through the second drive oil circuit 15, and the original oil in the first drive oil circuit 14 is sucked into the oil delivery channel 10 by the negative pressure of the oil delivery channel 10 on the first drive oil circuit 14, completing the riveting operation;

[0075] S4b, during the riveting process, when the external load is large, the pressure of the high-pressure oil circuit 20 on the bypass valve 17 increases, thereby pushing the valve core of the bypass valve 17 to change the state of the bypass valve 17, so that the low-pressure oil circuit 21 is connected with the oil delivery channel 10, and the oil enters the combined plunger pump body 8 from the oil tank 3 through the oil delivery channel 10, and a part of it flows out from the high-pressure oil outlet 18 to the high-pressure oil circuit 20, and the other part flows out from the low-pressure oil outlet 19 to the low-pressure oil circuit 21 and then flows into the oil delivery channel 10 through the bypass valve 17. After entering the high-pressure oil circuit 20, the oil enters the second drive oil circuit 15 through the electromagnetic reversing valve 13. The oil pushes the working head piston 12 to move toward the riveting working head 1 through the second drive oil circuit 15, and the original oil in the first drive oil circuit 14 is sucked into the oil delivery channel 10 by the negative pressure of the oil delivery channel 10 on the first drive oil circuit 14, completing the riveting operation;

[0076] S4c, during the riveting process, the pressure of the hydraulic system is detected by the pressure sensor 23. When the valve or control system fails, the pressure of the hydraulic system reaches the limit pressure of the safety valve 22, and the safety valve 22 will open to connect the oil delivery channel 10 with the high-pressure oil circuit 20, limiting the maximum pressure of the system to the pressure value set by the safety valve 22;

[0077] S4e, during the riveting process, the control part in the power supply and control unit 5 reads the parameters of the pressure sensor 23 provided on the safety valve 22, calculates the actual riveting force and compares the actual riveting force with the preset riveting force. When the actual riveting force reaches the preset riveting force, the electromagnetic reversing valve 13 is reversed, the high-pressure oil circuit 20 is connected with the first drive oil circuit 14 and the oil delivery channel 10 is connected with the second drive oil circuit 15. The oil in the high-pressure oil circuit 20 enters the first drive oil circuit 14 through the electromagnetic reversing valve 13, and the oil enters the piston chamber 16 from the front side of the piston chamber 16 to push the front end of the working head piston 12, so that the working head piston 12 moves toward the riveting work head 1, and the original oil in the second drive oil circuit 15 is sucked into the oil delivery channel 10 by the negative pressure of the oil delivery channel 10 on the second drive oil circuit 15, so as to realize the retraction operation of the riveting work head 1;

[0078] S5a. During the retraction process, the control part in the power supply and control unit 5 reads the parameters of the pressure sensor 23 on the safety valve 22, calculates the oil pressure of the high-pressure oil circuit 20 when the riveting work head 1 retracts, and compares the actual retraction oil pressure with the preset retraction pressure. When the actual retraction oil pressure reaches the preset retraction pressure, the control part in the power supply and control unit 5 controls the motor to stop, and the riveting is completed.

[0079] The working principle of this embodiment is described as follows: Fig.10 As shown, batteries are used as energy sources, which is convenient for carrying. The motor converts electrical energy into mechanical energy to drive the crankshaft 6 to rotate. The crankshaft 6 pushes the plunger 9 in the combined plunger pump body 8 to make reciprocating motion. The pressure fluid is generated by the change of the volume chamber. The hydraulic system is divided into two branches: low-pressure and high-flow and high-pressure and low-flow. When the external load is small, the working head is mainly driven by the low-pressure and high-flow branch to move quickly. When the external load becomes larger, the low-pressure bypass valve 17 is activated, and the low-pressure oil flows back to the oil tank 3. The high-pressure and low-flow branch drives the working head to complete the riveting process at a relatively slow speed. A combination of high and low pressure is used to achieve a relative balance between efficiency and total power. A safety valve 22 is set in the hydraulic system to limit the maximum pressure of the system. When the valve or control system fails, the hydraulic system pressure reaches the limit pressure of the safety valve 22, and the safety valve 22 will open to limit the maximum pressure of the system to the pressure value set by the safety valve 22, thereby improving the overall safety of the system.

[0080] A pressure sensor 23 is provided on the riveting tool. The oil pressure area of ​​the working head is determined by the mechanism structure. The real-time output force can be calculated by multiplying the pressure and the area. The action flow of the electric hydraulic riveting tool is controlled by the MCU program. It is equipped with a control button, a small OLED display, and three function buttons. The riveting force and return stop force can be set through the control button. The set parameters are displayed on the OLED display. The control button is used to send riveting instructions to the control system.

[0081] When the control system receives the riveting instruction, the electromagnetic reversing valve 13 is reversed, and the pressure oil circuit is switched to the working chamber of the working head, so that the second driving oil circuit 15 is connected with the oil delivery channel 10, and the riveting working head 1 is pushed to start the riveting stroke; during the process, the MCU calculates the output riveting force by monitoring the feedback value of the pressure sensor 23. When the riveting force is reached, the electromagnetic reversing valve 13 is reversed, and the riveting working head 1 performs a return motion; during the return process, the MCU continues to monitor the pressure value change, and calculates the return force by the product of the calculated pressure and the return chamber area. When the return force reaches the set value, the motor stops, and a riveting cycle is completed.

[0082] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. According to the technical essence of the present invention, within the spirit and principles of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. An integrated handheld electric hydraulic riveting tool, comprising a riveting working head (1) for performing a riveting action, characterized in that: The device also includes a hydraulic pump assembly (2) for conveying oil into the riveting work head (1) to drive the riveting work head (1) to perform a riveting action, the hydraulic pump assembly (2) being connected to an oil tank (3) for storing oil, the hydraulic pump assembly (2) being connected to an electric drive unit (4) for driving the hydraulic pump assembly (2) to operate, the electric drive unit (4) being connected to a power supply and a control unit (5), and the riveting work head (1), the oil tank (3), the electric drive unit (4), the power supply and the control unit (5) are all mounted on the hydraulic pump assembly (2); A crankshaft (6) for directly driving the hydraulic pump assembly (2) is provided in the hydraulic pump assembly (2), and an output shaft (7) of a motor connected to the rear end of the crankshaft (6) is provided in the electric drive unit (4); The hydraulic pump assembly (2) comprises a main body (24), the main body (24) being connected to at least one combined plunger pump body (8), the at least one combined plunger pump body (8) being connected to an oil tank (3), and a plunger (9) having a bottom end for contacting a side wall of a crankshaft (6) being provided in the combined plunger pump body (8); There are two combined plunger pump bodies (8) symmetrically arranged on the left and right sides of the main body (24); there is one oil tank (3) arranged above one of the combined plunger pump bodies (8) and connected to the combined plunger pump body (8); and an oil delivery channel (10) is provided in the main body (24) to connect the oil tank (3) with the combined plunger pump body (8) located on the other side of the main body (24); The main body (24) is provided with a crankshaft cavity (11) for accommodating the crankshaft (6), and the oil delivery channel (10) is in communication with the crankshaft cavity (11); when the crankshaft (6) is installed in the crankshaft cavity (11), the crankshaft cavity (11) is only in communication with the oil delivery channel (10); The riveting working head (1) is provided with a working head piston (12), and the main body (24) is connected to an electromagnetic reversing valve (13) for controlling the forward and backward movement of the working head piston (12); The main body (24) is provided with a first drive oil circuit (14) and a second drive oil circuit (15) for connecting the riveting working head (1) and the electromagnetic reversing valve (13); the riveting working head (1) is provided with a piston chamber (16) for allowing the working piston head to move back and forth; the first drive oil circuit (14) is connected to the front side of the piston chamber (16); and the second drive oil circuit (15) is connected to the rear side of the piston chamber (16); The main body (24) is provided with a bypass valve (17), the combined plunger pump body (8) is provided with a high-pressure oil outlet (18) and a low-pressure oil outlet (19), a high-pressure oil circuit (20) connecting the high-pressure oil outlet (18) with the electromagnetic reversing valve (13) and a low-pressure oil circuit (21) connecting the low-pressure oil outlet (19) with the bypass valve (17) are provided in the main body (24), the electromagnetic reversing valve (13) is connected to the oil delivery channel (10) and the high-pressure oil circuit (20), the bypass valve (17) is connected to the oil delivery channel (10), the low-pressure oil circuit (21) and the high-pressure oil circuit (20), the high-pressure oil circuit (20) is connected to the end surface of the valve core of the bypass valve (17), and the bypass valve (17) has a low-pressure state that cuts off the oil delivery channel (10) and the low-pressure oil circuit (21) and a high-pressure state that connects the oil delivery channel (10) and the low-pressure oil circuit (21); The main body (24) is provided with a safety valve (22) and a pressure sensor (23); the safety valve (22) is connected to the oil delivery channel (10) and the high-pressure oil circuit (20); and the pressure sensor (23) is provided on the safety valve (22).

2. A riveting method using an integrated handheld electric hydraulic riveting tool, characterized in that: The integrated handheld electric hydraulic riveting tool as claimed in claim 1 comprises the following steps: S1, aligning the riveting working head (1) with the rivet to put them in a riveting preparation state; S2, start the power switch to make the output shaft (7) of the motor rotate around its own axis; S3, the output shaft (7) of the motor drives the crankshaft (6) to rotate around its own axis; S4, the crankshaft (6) drives the hydraulic pump assembly (2) to drive the riveting working head (1) to perform the riveting operation; S5. After riveting is completed, the riveting head (1) is removed from the rivet.

3. The riveting method of the integrated handheld electric hydraulic riveting tool according to claim 2, characterized in that: The following steps are also included: S401. Before the riveting operation is performed, the electromagnetic reversing valve (13) connects the high-pressure oil circuit (20) with the second drive oil circuit (15) and connects the oil delivery channel (10) with the first drive oil circuit (14). The oil flows from the oil tank (3) through the oil delivery channel (10) into the combined plunger pump body (8), flows out from the high-pressure oil outlet (18) into the high-pressure oil circuit (20), and then enters the second drive oil circuit (15) through the electromagnetic reversing valve (13). The oil pushes the working head piston (12) to move toward the outside of the riveting working head (1) through the second drive oil circuit (15); S4a. During the riveting operation, the oil flows from the oil tank (3) into the combined plunger pump body (8) through the oil delivery channel (10), flows out from the high-pressure oil outlet (18) into the high-pressure oil circuit (20), and then enters the second drive oil circuit (15) through the electromagnetic reversing valve (13). The oil pushes the working head piston (12) to move toward the outside of the riveting working head (1). During the riveting process, when the external load is relatively small, the oil enters the combined plunger pump body (8) from the oil tank (3) through the oil delivery channel (10), flows out from the high-pressure oil outlet (18) to the high-pressure oil circuit (20), and then enters the second drive oil circuit (15) through the electromagnetic reversing valve (13). The oil pushes the working head piston (12) to move toward the outside of the riveting working head (1) through the second drive oil circuit (15). The original oil in the first drive oil circuit (14) is sucked into the oil delivery channel (10) by the negative pressure effect of the oil delivery channel (10) on the first drive oil circuit (14), thereby completing the riveting operation. S4b. During the riveting process, when the external load is large, the pressure of the high-pressure oil circuit (20) on the bypass valve (17) increases, thereby pushing the valve core of the bypass valve (17) to change the state of the bypass valve (17), so that the low-pressure oil circuit (21) is connected to the oil delivery channel (10), and the oil enters the combined plunger pump body (8) from the oil tank (3) through the oil delivery channel (10), and a part of the oil flows out from the high-pressure oil outlet (18) into the high-pressure oil circuit (20), and the other part flows out from the low-pressure oil outlet (19). After exiting the low-pressure oil circuit (21), the oil passes through the bypass valve (17) and flows into the oil delivery channel (10). After entering the high-pressure oil circuit (20), the oil passes through the electromagnetic reversing valve (13) and enters the second drive oil circuit (15). The oil pushes the working head piston (12) to move toward the outside of the riveting working head (1) through the second drive oil circuit (15). The oil originally in the first drive oil circuit (14) is sucked into the oil delivery channel (10) by the negative pressure effect of the oil delivery channel (10) on the first drive oil circuit (14), thereby completing the riveting operation. S4c, during the riveting process, the pressure of the hydraulic system is detected by the pressure sensor (23). When a valve or control system fails, the pressure of the hydraulic system reaches the limit pressure of the safety valve (22), and the safety valve (22) opens to connect the oil delivery channel (10) with the high-pressure oil circuit (20), thereby limiting the maximum pressure of the system to within the pressure value set by the safety valve (22); S4e. During the riveting process, the control part in the power supply and control unit (5) reads the parameters of the pressure sensor (23) provided on the safety valve (22), calculates the actual riveting force and compares the actual riveting force with the preset riveting force. When the actual riveting force reaches the preset riveting force, the electromagnetic reversing valve (13) is reversed to connect the high-pressure oil circuit (20) with the first drive oil circuit (14) and connect the oil delivery channel (10) with the second drive oil circuit (15). The high-pressure oil circuit (20) is ) enters the first drive oil circuit (14) through the electromagnetic reversing valve (13), and the oil enters the piston chamber (16) from the front side of the piston chamber (16) to push the front end of the working head piston (12), so that the working head piston (12) moves toward the riveting working head (1), and the original oil in the second drive oil circuit (15) is sucked into the oil delivery channel (10) by the negative pressure effect of the oil delivery channel (10) on the second drive oil circuit (15), thereby realizing the retraction operation of the riveting working head (1); S5a, during the retraction process, the control part in the power supply and control unit (5) reads the parameters of the pressure sensor (23) on the safety valve (22), calculates the oil pressure of the high-pressure oil circuit (20) when the riveting working head (1) retracts, and compares the actual retraction oil pressure with the preset retraction pressure. When the actual retraction oil pressure reaches the preset retraction pressure, the control part in the power supply and control unit (5) controls the motor to stop, and the riveting is completed.

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