Automatic flexible assembly equipment and assembly method for variable stiffness valve ball

Abstract

The present invention discloses an automated flexible assembly equipment and an assembly method for a variable-rigidity valve ball, and relates to the field of mechanical devices for assembling valve balls, comprising: a robot, connected to a gripper via a variable-rigidity mechanism; a workbench; a first assembly precision positioning mechanism, capable of collecting the spatial position of a valve housing, the first assembly precision positioning mechanism comprising a position receiver, arranged on the gripper; a second assembly precision positioning mechanism, comprising a pair of signal transmitting ends, the signal transmitting ends being respectively arranged opposite to the horizontal pipe mouth ends of the valve housing, and when the valve ball enters the valve housing, the signal transmitting ends send a positioning signal to the valve ball; a control unit, for controlling the robot and the variable-rigidity mechanism; the assembly equipment is switched to a rigid connection mode in the grasping stage to ensure the grasping position and the handling accuracy, and is switched to a flexible connection mode in the assembly stage to avoid affecting the assembly accuracy and scratches caused by hard assembly.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical devices for assembling valve balls, and more specifically, relates to automatic flexible assembly equipment and an assembly method for variable-rigidity valve balls. Background Art

[0002] The valve mainly consists of a valve housing, a valve cover, a valve core, etc. When assembling the valve, in addition to installing each component in place, the accuracy of the assembly also needs to be considered. Since the internal space provided by the valve housing is very limited, manual installation is often used when assembling the valve core. Manual installation has problems such as insufficient installation position accuracy and low efficiency. Especially for ball-type valve cores, if the ball makes a sound and rubs during the assembly process, the scratched part will be affected by the impact and pressure of the medium in the valve during the later operation of the valve, which can easily cause damage to the valve ball. Therefore, in view of the problem that the internal space of the valve housing is small, the valve ball is difficult to assemble, and at the same time, the assembly scratches of the valve ball are reduced, there is an urgent need for a device that can adapt to the limited space inside the valve housing and assemble the valve ball efficiently and accurately. Summary of the invention

[0003] The purpose of the present invention is to address the deficiencies in the prior art and to provide an automated flexible assembly equipment and method for a variable-rigidity valve ball. The assembly equipment can achieve efficient and precise assembly of the valve ball. During the grasping stage of the valve ball, the variable-rigidity mechanism is switched to a rigid connection mode, thereby ensuring the grasping position and handling accuracy. During the assembly stage of the valve ball and the valve housing, the variable-rigidity mechanism is switched to a flexible connection mode, and the assembly posture is adaptively adjusted according to the contact mode between the valve ball and the inner cavity of the valve housing to avoid affecting the assembly accuracy and scratches caused by hard assembly.

[0004] In order to achieve the above object, the present invention provides a variable stiffness valve ball automatic flexible assembly equipment, comprising:

[0005] The robot is connected to a gripper through a variable stiffness mechanism, and the gripper is used to clamp and fix the valve ball;

[0006] A workbench for placing the valve housing;

[0007] A first assembly precision positioning mechanism, capable of acquiring the spatial position of the valve housing, the first assembly precision positioning mechanism comprising a position receiver, and the position receiver is arranged on the gripper;

[0008] The second assembly precision positioning mechanism comprises a pair of signal transmitting ends, the signal transmitting ends are respectively arranged opposite to the horizontal pipe opening ends of the valve housing, and when the valve ball enters the valve housing, the signal transmitting ends send a positioning signal to the valve ball;

[0009] A control unit controls the robot and the variable stiffness mechanism through measurement data of the first assembly precision positioning mechanism and the second assembly precision positioning mechanism.

[0010] Optionally, the variable stiffness mechanism comprises:

[0011] A fixed platform, one side of which is connected to the robot;

[0012] A motion platform, one side of which is connected to the gripper, and the motion platform is arranged corresponding to the fixed platform;

[0013] At least 6 groups of variable stiffness connecting rods are arranged between the fixed platform and the moving platform, the variable stiffness connecting rods are evenly arranged along the circumference of the fixed platform, and the variable stiffness connecting rods are connected to the control unit;

[0014] A fixed connecting rod is arranged between the fixed platform and the moving platform, and two ends of the fixed connecting rod are respectively arranged in the center of the fixed platform and the moving platform;

[0015] The ends of the variable stiffness connecting rod and the fixed connecting rod are respectively connected to the fixed platform and the moving platform through ball joint pairs.

[0016] Optionally, the variable stiffness connecting rod includes a variable stiffness connecting rod inner rod and a variable stiffness connecting rod outer rod, and the two are connected by a spring. One end of the variable stiffness connecting rod outer rod is sleeved on the outside of the variable stiffness connecting rod inner rod. Before the valve ball enters the valve housing, the variable stiffness connecting rod inner rod and the variable stiffness connecting rod outer rod perform relative telescopic movement, thereby driving the motion platform and the valve ball to adjust the angular position of entering the valve housing.

[0017] Optionally, the variable stiffness link is obliquely arranged between the fixed platform and the moving platform, and the variable stiffness link is in a positive V shape with the adjacent variable stiffness link arranged in the clockwise direction, and the variable stiffness link is in an inverted V shape with the adjacent variable stiffness link arranged in the counterclockwise direction.

[0018] Optionally, the gripper comprises at least three clamping parts, the clamping parts are evenly distributed on the valve ball, and the position receivers are respectively arranged on the clamping parts.

[0019] Optionally, the first assembly precision positioning mechanism comprises a three-coordinate measuring machine, and the three-coordinate measuring machine can measure the position of the vertical nozzle end of the valve housing and the placement angle of the valve housing.

[0020] Optionally, the signal transmitting end includes a laser ranging sensor connected to the control unit, and a ranging signal emitted by the laser ranging sensor falls on the valve ball through a horizontal pipe mouth end of the valve housing.

[0021] Optionally, the signal transmitting end includes an electromagnet, the magnetic end of the electromagnet faces the horizontal pipe mouth end passing through the valve housing and applies magnetism to the valve ball, and a plurality of force sensors are evenly arranged between the gripper and the valve ball, and the force sensors are connected to the control unit.

[0022] Optionally, the gripper and the valve ball are fixed by pneumatic or mechanical clamping.

[0023] The present invention also provides a variable stiffness valve ball automatic flexible assembly method, using the variable stiffness valve ball automatic flexible assembly equipment, characterized in that the method comprises:

[0024] Place the valve housing on the workbench and fix the valve ball with the gripper;

[0025] The first assembly precision positioning mechanism measures the spatial position of the valve housing and the valve ball to generate first measurement data;

[0026] The robot moves the gripper according to the first measurement data, and the variable stiffness mechanism is in a rigid connection mode;

[0027] Until the valve ball moves to the position directly above the vertical pipe mouth end of the valve housing, the second assembly precision positioning mechanism transmits a positioning signal to the horizontal pipe mouth end of the valve housing, measures the offset position of the valve ball, and generates second measurement data;

[0028] The variable stiffness mechanism moves the gripper according to the second measurement data, and the variable stiffness mechanism is in a flexible connection mode until the valve ball is installed in place in the valve housing.

[0029] The present invention provides a variable-rigidity valve ball automated flexible assembly equipment and assembly method, which has the beneficial effect that the assembly equipment integrates a variable-rigidity mechanism at the end of a robot to achieve rigid connection of the valve ball in the grasping and handling stage and flexible connection in the assembly stage, and switches between the two modes according to the adaptive stiffness, thereby ensuring assembly efficiency while ensuring assembly accuracy and assembly quality of the valve ball.

[0030] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0032] Figure 1 A schematic structural diagram of variable-rigidity valve ball automated flexible assembly equipment according to an embodiment of the present invention is shown.

[0033] Figure 2 A schematic diagram showing the connection between a variable stiffness mechanism and a gripper according to an embodiment of the present invention is shown.

[0034] Figure 3 A schematic structural diagram of a variable stiffness mechanism according to an embodiment of the present invention is shown.

[0035] Figure 4 A control flow chart of an automated flexible assembly method for a variable-rigidity valve ball according to an embodiment of the present invention is shown.

[0036] Description of reference numerals:

[0037] 1. Robot; 2. Variable stiffness mechanism; 3. Gripper; 4. Valve ball; 5. Workbench; 6. Valve housing; 7. Signal transmitting end; 8. Horizontal pipe end; 9. Fixed platform; 10. Moving platform; 11. Variable stiffness connecting rod; 12. Fixed connecting rod; 13. Ball joint pair; 14. Inner rod of variable stiffness connecting rod; 15. Outer rod of variable stiffness connecting rod; 16. Vertical pipe end. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0039] The present invention provides a variable stiffness valve ball automatic flexible assembly equipment, comprising:

[0040] The robot is connected to the gripper through a variable stiffness mechanism, and the gripper is used to clamp and fix the valve ball;

[0041] A workbench for placing the valve housing;

[0042] A first assembly precision positioning mechanism, capable of collecting the spatial position of the valve housing, the first assembly precision positioning mechanism comprising a position receiver, and the position receiver is arranged on the gripper;

[0043] The second assembly precision positioning mechanism includes a pair of signal transmitting ends, which are respectively arranged opposite to the horizontal pipe opening ends of the valve housing. When the valve ball enters the valve housing, the signal transmitting end sends a positioning signal to the valve ball.

[0044] The control unit controls the robot and the variable stiffness mechanism through the measurement data of the first assembly precision positioning mechanism and the second assembly precision positioning mechanism.

[0045] Specifically, the assembly equipment includes a robot and a workbench. The robot is used to grab the valve ball, and the workbench is used to place the valve housing. In order to avoid the problem of collision of the valve ball during the assembly and installation of the valve ball into the valve housing, and to ensure the assembly efficiency, a variable stiffness mechanism is set between the robot and the gripper. When grabbing and transporting the valve ball, the variable stiffness mechanism is switched to a rigid connection mode, so that the transfer of the valve ball is achieved only by the movement of the robot. When the valve ball is assembled into the valve housing, the variable stiffness mechanism is switched to a flexible connection mode, so that the edge stiffness mechanism begins to deform and rotate, driving the valve ball to rotate at any angle, and enabling the valve ball to achieve six degrees of freedom in space. Movement, so that the position accuracy of the valve ball entering the valve housing is guaranteed, and there will be no collision between the valve ball and the valve housing. The assembly equipment also includes a first assembly precision positioning mechanism and a second assembly precision positioning mechanism. The first assembly precision positioning mechanism determines the spatial position of the valve housing by measurement, and also obtains the spatial position of the gripper in real time through a position receiver. The robot moves the valve ball to above the vertical pipe mouth end of the valve housing through the measurement data of the first assembly precision positioning mechanism, and then starts the second assembly precision positioning mechanism to transmit a positioning signal through the signal transmitting end. The positioning signal passes through the horizontal pipe mouth end of the valve housing and is shot into the three-port connection of the valve housing. When the valve ball descends to the inside of the valve housing, the positioning signal is shot onto the surface of the valve ball to obtain whether the valve ball is in the center position between the two signal transmitting ends. In this way, the position of the valve ball can be adjusted correctly to avoid collision between the valve ball and the valve housing.

[0046] Optionally, the variable stiffness mechanism includes:

[0047] A fixed platform, one side of which is connected to the robot;

[0048] A motion platform, one side of which is connected to the gripper, and the motion platform and the fixed platform are arranged correspondingly;

[0049] At least 6 groups of variable stiffness connecting rods are arranged between the fixed platform and the moving platform, the variable stiffness connecting rods are evenly arranged along the circumference of the fixed platform, and the variable stiffness connecting rods are connected to the control unit;

[0050] A fixed connecting rod is arranged between the fixed platform and the moving platform, and two ends of the fixed connecting rod are arranged in the center of the fixed platform and the moving platform respectively;

[0051] The ends of the variable stiffness connecting rod and the fixed connecting rod are connected to the fixed platform and the moving platform respectively through ball joint pairs.

[0052] Specifically, in the assembly equipment, the variable stiffness mechanism includes a fixed platform, a moving platform, a variable stiffness connecting rod and a fixed connecting rod. The fixed platform and the moving platform are parallel to each other and have similar or identical areas. A plurality of groups of variable stiffness connecting rods are evenly arranged along the circumference of the two platforms, and a fixed connecting rod is arranged at the central position of the two platforms. Since the variable stiffness connecting rod is connected to the fixed platform and the moving platform through a ball joint pair, the variable stiffness connecting rod and the platform can rotate relative to each other; when the variable stiffness mechanism is in a rigid connection mode, the ball joint pair between the fixed connecting rod and the fixed platform and the moving platform is clamped, so that the fixed platform The parallel relationship between the platform and the motion platform remains unchanged, the variable stiffness mechanism is in a locked state, and the valve ball can only achieve three-degree-of-freedom spatial movement through the robot; when the variable stiffness mechanism is in a flexible connection mode, the ball joints at both ends of the fixed connecting rod can move freely, and the lengths of each variable stiffness connecting rod change, so that the motion platform and the fixed platform form a certain angle, so that the gripper and the valve ball are driven by the motion platform, and the valve ball can achieve six-degree-of-freedom spatial movement, so that the posture of the valve ball is adapted to the valve housing, and no collision occurs during the assembly of the valve ball.

[0053] Optionally, the variable stiffness connecting rod includes an inner rod and an outer rod, which are connected by a spring. One end of the outer rod is sleeved on the outside of the inner rod. Before the valve ball enters the valve housing, the inner rod and the outer rod move telescopically relative to each other, thereby driving the motion platform and the valve ball to adjust the angular position of entering the valve housing.

[0054] Specifically, the variable stiffness connecting rod includes an inner rod and an outer rod, which are slidably mounted on each other, and a spring is used to adjust the telescopic length of the variable stiffness connecting rod. When the motion platform drives the valve ball to rotate in one direction, the variable stiffness connecting rod is shortened at the position of the motion platform after the turn, and the variable stiffness connecting rod is extended at the position of the platform on the other side after the turn. In this way, the rotation of the motion platform can be realized under the telescopic change of the variable stiffness connecting rod, and the structure is simple and stable.

[0055] Optionally, the variable stiffness link is obliquely arranged between the fixed platform and the moving platform, the variable stiffness link and the adjacent variable stiffness link arranged in the clockwise direction form a positive V shape, and the variable stiffness link and the adjacent variable stiffness link arranged in the counterclockwise direction form an inverted V shape.

[0056] Specifically, the variable stiffness connecting rod forms an oblique connection with the fixed platform and the moving platform, so that when the moving platform needs to rotate in one direction, the two adjacent variable stiffness connecting rods in this direction can change their lengths at the same time, providing stable support for the moving platform, ensuring that the gripper can rotate with the valve ball to a specified angle, and that the valve ball remains stable after rotating to the specified angle.

[0057] Optionally, the gripper includes at least three clamping parts, the clamping parts are evenly distributed on the valve ball, and position receivers are respectively arranged on the clamping parts.

[0058] Optionally, the first assembly precision positioning mechanism comprises a three-coordinate measuring machine, which can measure the position of the vertical nozzle end of the valve housing and the placement angle of the valve housing.

[0059] Specifically, the gripper clamps and fixes the valve ball through multiple clamping parts, and a position receiver is respectively arranged on each clamping part, so that at least three position receivers can determine the spatial position of the valve ball. The first assembly precision positioning mechanism confirms the position of the valve ball through the position receiver, and can also measure the end face position and the overall position of the vertical pipe mouth end of the valve housing. In this way, the valve ball can be moved to the top of the vertical pipe mouth end of the valve housing through the robot based on the above measurement data, and it can be confirmed in which direction the valve ball enters the valve housing and how much distance it needs to enter before it can be installed in the valve housing.

[0060] Optionally, the signal transmitting end includes a laser distance measuring sensor connected to the control unit, and the distance measuring signal emitted by the laser distance measuring sensor falls on the valve ball through the horizontal pipe mouth end of the valve housing.

[0061] Specifically, the signal transmitting end in the second assembly precision positioning mechanism can be a laser ranging sensor, which are respectively arranged on both sides of the valve housing, and the valve housing is located at the midpoint of the two laser ranging sensors. When the valve ball is about to enter the valve housing, the laser ranging sensor transmits a ranging signal along the horizontal pipe end to the valve housing. When part of the valve ball enters the valve housing, the ranging signal can detect the distance between the two sides of the valve ball. Only when the measurement data of the two laser ranging sensors are the same, the horizontal position of the valve ball in the valve housing is ensured to be correct, and then the entry distance of the valve ball is obtained according to the first assembly precision positioning mechanism. In this way, the valve ball will not be scratched with the valve housing during the assembly process, thereby realizing efficient and precise assembly of the valve ball.

[0062] Optionally, the signal transmitting end includes an electromagnet, the magnetic end of the electromagnet faces the horizontal pipe end passing through the valve housing and applies magnetism to the valve ball, and a plurality of force sensors are evenly arranged between the gripper and the valve ball, and the force sensors are connected to the control unit.

[0063] Specifically, the signal transmitting end in the second assembly precision positioning mechanism can also be an electromagnet, which is also arranged on both sides of the valve housing, and the valve housing is also located at the midpoint of the two electromagnets. When the valve ball is about to enter the valve housing, the electromagnet starts to be energized, and the part of the valve ball entering the valve housing will be offset by the magnetic effect generated by the electromagnet. This offset can be measured by a force sensor. When the measured values ​​of all the force sensors are the same, it means that the valve ball is in the exact center of the valve housing. In this way, the valve ball and the valve housing will not collide during the assembly process, and the valve ball will not be damaged, thereby ensuring the installation accuracy and integrity of the valve ball.

[0064] Optionally, the gripper and the valve ball are fixed by pneumatic or mechanical clamping.

[0065] The present invention also provides a variable stiffness valve ball automatic flexible assembly method, using the variable stiffness valve ball automatic flexible assembly equipment, characterized in that the method comprises:

[0066] Place the valve housing on the workbench and fix the valve ball with the gripper;

[0067] The first assembly precision positioning mechanism measures the spatial position of the valve housing and the valve ball to generate first measurement data;

[0068] The robot moves the gripper according to the first measurement data, and the variable stiffness mechanism is in a rigid connection mode;

[0069] Until the valve ball moves to the position directly above the vertical pipe mouth end of the valve housing, the second assembly precision positioning mechanism transmits a positioning signal to the horizontal pipe mouth end of the valve housing, measures the offset position of the valve ball, and generates second measurement data;

[0070] The variable stiffness mechanism moves the gripper according to the second measurement data, and the variable stiffness mechanism is in a flexible connection mode until the valve ball is installed in place in the valve housing.

[0071] Specifically, when the assembly equipment is used to assemble the valve ball, the first assembly precision positioning mechanism is used for preliminary positioning. The three-dimensional coordinate measuring instrument measures the spatial position of the profile and hole of the vertical pipe mouth end of the valve housing. It is also necessary to confirm the overall position and placement angle of the valve housing, and then receive the measurement data of the position receiver in real time. The valve ball is moved to the vertical pipe mouth end of the valve housing by the robot. In this process, the stiffness mechanism is changed to a rigid connection mode; when the valve ball enters the valve housing, the second assembly precision positioning mechanism starts to start, and the distance measuring sensor or electromagnet sends a positioning signal to ensure the installation accuracy of the valve ball when it enters the valve housing. In this process, the stiffness mechanism is changed to a flexible connection mode. While the robot drives the valve ball to extend into the valve housing, the stiffness mechanism rotates and adjusts the valve ball to achieve spatial movement in six degrees of freedom, thereby ensuring efficient and precise assembly of the valve ball.

[0072] Example

[0073] like Figures 1 to 4 As shown, the present invention provides an automatic flexible assembly equipment for a variable stiffness valve ball, comprising:

[0074] The robot 1 is connected to the gripper 3 via the variable stiffness mechanism 2, and the gripper 3 is used to clamp and fix the valve ball 4;

[0075] A workbench 5, used for placing a valve housing 6;

[0076] A first assembly precision positioning mechanism, capable of collecting the spatial position of the valve housing 6, the first assembly precision positioning mechanism comprising a position receiver, and the position receiver is arranged on the gripper 3;

[0077] The second assembly precision positioning mechanism includes a pair of signal transmitting ends 7, which are respectively arranged opposite to the horizontal pipe end 8 of the valve housing 4. When the valve ball 4 enters the valve housing 6, the signal transmitting end 7 sends a positioning signal to the valve ball 4;

[0078] The control unit controls the robot 1 and the variable stiffness mechanism 2 through the measurement data of the first assembly precision positioning mechanism and the second assembly precision positioning mechanism.

[0079] In this embodiment, the variable stiffness mechanism 2 includes:

[0080] A fixed platform 9, one side of which is connected to the robot 1;

[0081] A moving platform 10, one side of which is connected to the gripper 3, and the moving platform 10 is arranged corresponding to the fixed platform 9;

[0082] At least 6 groups of variable stiffness connecting rods 11 are arranged between the fixed platform 9 and the moving platform 10. The variable stiffness connecting rods 11 are evenly arranged along the circumference of the fixed platform 9. The variable stiffness connecting rods 11 are connected to the control unit.

[0083] A fixed connecting rod 12 is arranged between the fixed platform 9 and the moving platform 10, and two ends of the fixed connecting rod 12 are respectively arranged in the center of the fixed platform 9 and the moving platform 10;

[0084] The ends of the variable stiffness connecting rod 11 and the fixed connecting rod 12 are connected to the fixed platform 9 and the moving platform 10 respectively through a ball joint pair 13 .

[0085] In this embodiment, the variable stiffness connecting rod 11 includes a variable stiffness connecting rod inner rod 14 and a variable stiffness connecting rod outer rod 15, which are connected by a spring. One end of the variable stiffness connecting rod outer rod 15 is sleeved on the outside of the variable stiffness connecting rod inner rod 14. Before the valve ball 4 enters the valve housing 6, the variable stiffness connecting rod inner rod 14 and the variable stiffness connecting rod outer rod 15 move telescopically relative to each other, thereby driving the motion platform 10 and the valve ball 4 to adjust the angular position of entering the valve housing 6.

[0086] In this embodiment, the variable stiffness link 11 is obliquely arranged between the fixed platform 9 and the moving platform 10. The variable stiffness link 11 forms a positive V-shape with the adjacent variable stiffness link 11 arranged in the clockwise direction, and the variable stiffness link 11 forms an inverted V-shape with the adjacent variable stiffness link 11 arranged in the counterclockwise direction.

[0087] In this embodiment, the gripper 3 includes at least three clamping parts, which are evenly distributed on the valve ball 4, and position receivers are respectively provided on the clamping parts.

[0088] In this embodiment, the first assembly precision positioning mechanism includes a three-coordinate measuring machine, which can measure the position of the vertical pipe mouth end 16 of the valve housing 6 and the placement angle of the valve housing 6 .

[0089] In this embodiment, the signal transmitting end 7 includes a laser distance measuring sensor connected to the control unit, and the distance measuring signal emitted by the laser distance measuring sensor falls on the valve ball 4 through the horizontal pipe mouth end 8 of the valve housing 6 .

[0090] In this embodiment, the signal transmitting end 7 includes an electromagnet, the magnetic end of the electromagnet faces the horizontal pipe end 8 passing through the valve housing 6 and applies magnetism to the valve ball 4, and a plurality of force sensors are evenly arranged between the gripper 3 and the valve ball 4, and the force sensors are connected to the control unit.

[0091] In this embodiment, the gripper 3 and the valve ball 4 are fixed in a pneumatic or mechanical clamping manner.

[0092] The present invention also provides a variable stiffness valve ball automatic flexible assembly method, using the variable stiffness valve ball automatic flexible assembly equipment, characterized in that the method comprises:

[0093] The valve housing 6 is fixedly placed on the workbench 5, and the gripper 3 clamps and fixes the valve ball 4;

[0094] The first assembly precision positioning mechanism measures the spatial positions of the valve housing 6 and the valve ball 4 to generate first measurement data;

[0095] The robot 1 moves the gripper 3 according to the first measurement data, and the variable stiffness mechanism 2 is in a rigid connection mode;

[0096] Until the valve ball 4 moves to the position directly above the vertical pipe end 16 of the valve housing 6, the second assembly precision positioning mechanism transmits a positioning signal into the horizontal pipe end 16 of the valve housing 6, measures the offset position of the valve ball 4, and generates second measurement data;

[0097] The variable stiffness mechanism 2 moves the gripper 3 according to the second measurement data, and the variable stiffness mechanism 2 is in a flexible connection mode until the valve ball 4 is installed in place in the valve housing 6 .

[0098] In summary, the variable-rigidity valve ball automated flexible assembly equipment is divided into two stages when assembling the valve ball 4 into the valve housing 6. When the valve ball 4 is grasped and moved by the robot 1, the first measurement data is measured according to the first assembly precision positioning mechanism, and the spatial position of the valve ball 4 and the valve housing 6 is determined before moving and installing. The variable-rigidity mechanism 2 is in a rigid connection mode to ensure the grasping position and the accuracy of transportation. When the valve ball 4 is placed in the valve housing 6, the second assembly precision positioning mechanism is opened to measure the second measurement data of the horizontal position of the valve ball 4 to determine the movement trajectory of the valve ball 4 in the valve housing 6. The variable-rigidity mechanism 2 is in a flexible connection mode to ensure the assembly accuracy of the valve ball 4 and reduce the scratches caused by hard assembly.

[0099] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An automatic flexible assembly equipment for variable stiffness valve balls, characterized in that: include: The robot is connected to a gripper through a variable stiffness mechanism, and the gripper is used to clamp and fix the valve ball; A workbench for placing the valve housing; A first assembly precision positioning mechanism, capable of collecting the spatial position of the valve housing, the first assembly precision positioning mechanism comprising a position receiver, the position receiver being arranged on the gripper; the first assembly precision positioning mechanism comprising a three-coordinate measuring instrument, the three-coordinate measuring instrument being capable of measuring the position of the vertical nozzle end of the valve housing and the placement angle of the valve housing; The second assembly precision positioning mechanism comprises a pair of signal transmitting ends, the signal transmitting ends are respectively arranged opposite to the horizontal pipe opening ends of the valve housing, and when the valve ball enters the valve housing, the signal transmitting ends send a positioning signal to the valve ball; A control unit, which controls the robot and the variable stiffness mechanism through measurement data of the first assembly precision positioning mechanism and the second assembly precision positioning mechanism; The signal transmitting end includes a laser distance measuring sensor connected to the control unit, the distance measuring signal emitted by the laser distance measuring sensor falls on the valve ball through the horizontal pipe mouth end of the valve housing, the laser distance measuring sensors are respectively arranged on both sides of the valve housing, and the valve housing is located at the midpoint of the two laser distance measuring sensors; or, the signal transmitting end includes an electromagnet, the magnetic end of the electromagnet faces the horizontal pipe mouth end passing through the valve housing and applies magnetism to the valve ball, the electromagnets are arranged on both sides of the valve housing, the valve housing is located at the midpoint of the two electromagnets, a plurality of force sensors are evenly arranged between the gripper and the valve ball, and the force sensors are connected to the control unit; The variable stiffness mechanism comprises: A fixed platform, one side of which is connected to the robot; A motion platform, one side of which is connected to the gripper, and the motion platform is arranged corresponding to the fixed platform; At least 6 groups of variable stiffness connecting rods are arranged between the fixed platform and the moving platform, the variable stiffness connecting rods are evenly arranged along the circumference of the fixed platform, and the variable stiffness connecting rods are connected to the control unit; A fixed connecting rod is arranged between the fixed platform and the moving platform, and two ends of the fixed connecting rod are respectively arranged in the center of the fixed platform and the moving platform; The ends of the variable stiffness connecting rod and the fixed connecting rod are connected to the fixed platform and the moving platform respectively through ball joints; when the variable stiffness mechanism is in a rigid connection mode, the ball joints between the fixed connecting rod and the fixed platform and the moving platform are clamped; The variable stiffness connecting rod comprises an inner rod and an outer rod, which are connected by a spring. One end of the outer rod is sleeved on the outside of the inner rod. Before the valve ball enters the valve housing, the inner rod and the outer rod perform relative telescopic movement, thereby driving the motion platform and the valve ball to adjust the angular position of entering the valve housing.

2. The variable stiffness valve ball automated flexible assembly equipment according to claim 1 is characterized in that: The variable stiffness connecting rod is obliquely arranged between the fixed platform and the moving platform, and the variable stiffness connecting rod and the adjacent variable stiffness connecting rod arranged in the clockwise direction are in a positive V shape, and the variable stiffness connecting rod and the adjacent variable stiffness connecting rod arranged in the counterclockwise direction are in an inverted V shape.

3. The variable stiffness valve ball automated flexible assembly equipment according to claim 1 is characterized in that: The gripper comprises at least three clamping parts, the clamping parts are evenly distributed on the valve ball, and the position receivers are respectively arranged on the clamping parts.

4. The variable stiffness valve ball automated flexible assembly equipment according to claim 1 is characterized in that: The gripper and the valve ball are fixed in a pneumatic or mechanical clamping manner.

5. A variable stiffness valve ball automated flexible assembly method, using the variable stiffness valve ball automated flexible assembly equipment according to any one of claims 1 to 4, characterized in that: The method includes: Place the valve housing on the workbench and fix the valve ball with the gripper; The first assembly precision positioning mechanism measures the spatial position of the valve housing and the valve ball to generate first measurement data; The robot moves the gripper according to the first measurement data, and the variable stiffness mechanism is in a rigid connection mode; Until the valve ball moves to the position directly above the vertical pipe mouth end of the valve housing, the second assembly precision positioning mechanism transmits a positioning signal to the horizontal pipe mouth end of the valve housing, measures the offset position of the valve ball, and generates second measurement data; The variable stiffness mechanism moves the gripper according to the second measurement data, and the variable stiffness mechanism is in a flexible connection mode until the valve ball is installed in place in the valve housing.

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