1. The structure and characteristics of tubular radiator

The chip type radiator core is made of multiple water pipes and multiple pieces of heat sink after baking and welding, the main parts are heat sink water pipe and heat sink, the key of the core manufacturing is the assembly of the two.

The cooling water pipe is a rectangular pipe made of H90Y0.1643 brass with bite seam, and the outer layer is plated with tin. The section shape is shown in 1, and the length varies with the type of radiator, generally 6801100mm. Its main characteristics are: 1) low dimensional accuracy, unstable section shape; 2) Poor rigidity, water pipe flatness deviation is large; 3) The surface is rough, and the flat tin layer is poor.

The heat sink is made of H62Y0.195 brass belt stamping, flanging on both sides, the structure is shown as follows: 1) stamping forming, hole size consistency is good; 2) Porous, and the hole to one side of the flange is a right Angle, multiple pieces of overlapping easy to jam each other; 3) Surface pressure wave reinforcement, poor flatness; 4) poor rigidity, easy to crimp; 5) The water pipe can only be strung in one direction.

2 Automatic sharding principle

The principle and method of automatic fragmentation proposed by us are as follows: vacuum technology is used to suck up the heat sink one by one, send it to the specified position and connect the water pipe. The difficulty and key lies in: 1) the heat sink is porous, the surface has wave tendons, the adsorption area for the suction head is very small, and is not conducive to adsorption; 2) The heat sink should be strung with hundreds of water pipes at the same time, and the positioning of water pipes and heat sinks is the key.

21. Vacuum suction test

In order to solve the suction problem, the original test as shown in 3 was carried out.

Test parameters: nozzle section 15mm3mm; Number of suction head 2; There are three kinds of erasers.

Test conclusions: 1) The soft rubber adhesive suction head can maintain good air tightness, easy to suck up the heat sink, can suck up the heat sink under the vacuum condition of about 340KPa. 2) Hard rubber adhesive suction head is not easy to form a vacuum, can not suck up the heat sink.

22 Multi-head working system

In order to realize automatic fragmentation, the heat sink must be kept flat and have certain positioning accuracy. The multi-head working system scheme as shown in Figure 4 is adopted in the actual design. Design parameters are as follows: suction F=10kg, pumping time t? 0.5s, the number of head suction n=34.

The system has sufficient suction and can keep the heat sink flat when it is sucked up.

4. The function of the vacuum suction valve is to prevent a suction head from leaking when working. The valve can be automatically closed to maintain the vacuum degree of the system. The suction head is the key of the system, the position of the suction head should be ensured in the corresponding hole and hole between the interval, the performance of the suction head according to the principle of test suction head: on the one hand, the contact surface of the suction head and the heat sink should be soft, to adapt to the corrugated shape of the heat sink surface, convenient to form a closed vacuum chamber; On the other hand, in order to prevent the overall deformation under the negative pressure of the suction head, the suction head is required to have a certain rigidity, so as to ensure the smoothness and positioning accuracy of the heat sink after suction. The two structures shown can be used in actual production. The all-rubber structure is made of polyurethane rubber with a hardness of 5060A, while the lip of the metal skeleton suction head is made of natural rubber attached to the metal skeleton.

In order to ensure that multiple suction heads work at the same time, the suction heads are uniformly installed on the suction cup plane, and a certain pressure should be applied to deform the suction heads to ensure the establishment of the vacuum system.

23 Segment positioning mechanism

The lower end of the water pipe can be fixed, but the upper end cannot be fixed completely according to the requirements of the cross-piece operation. Analyzing the structural characteristics of the water pipe, it is found that the rectangular section has good stability and rigidity in the long side direction, but poor in the short side direction. Therefore, a pair of auxiliary positioning mechanism, which can swing alternately between the Haffler plate and the suction cup, is adopted at the upper end. The two movements are interlocked, which mainly restricts the swing in the short side direction of the water pipe. The principle of action is: when the chip is sent, the sucker absorbs the heat sink set on the water pipe, the hafu plate opens, the sucker and the heat sink through; When returning, the hafu plate is closed first, and the suction cup is removed from the water pipe. This can not only complete the action of the piece, but also maintain the accurate positioning of the water pipe. In order to reduce the influence of positioning error on the cascade, a guide bit is used at the end of the water pipe. Its head has a large guide slope, so the heat sink and suction cup can be imported within a certain error range.

The lower end of the water pipe is positioned by the positioning bit, and the water pipe is inserted in the guiding bit according to the different types of the radiator in an orderly arrangement. The structure principle of segment positioning system is shown as follows.

The characteristics of this positioning mechanism: 1) strong adaptability, positioning parts in the structure has a strong versatility, different types of radiator core, only change the layout and number of the cooling water pipe and the length of the water pipe can be; 2) Reliable positioning, positioning mechanism adopts the lower end fixed, the upper end alternate positioning, constraints all degrees of freedom, and in the direction of poor rigidity and stability to increase the auxiliary support, reliable movement; 3) Easy loading and unloading, positioning mechanism using short brazing positioning, pipe row to use the current production process of pipe row and core unloading method.

3 Movement analysis of automatic assembly of radiator core

The motion of automatic assembly of radiator core can be divided into main motion and auxiliary motion, as shown. The main motion includes core assembly action and auxiliary carding action. The auxiliary motion includes the fragment feeding action, which takes the piece from the radiator buffer to the assembly position. In the automatic assembly machine, except the core assembly action is stepping drive, the rest are pneumatic.

The action process of the main movement is that the stepper motor drives the lead screw to lift the comb to the position of the comb, and the cylinder pushes the comb to the position. After the position is in place, the stepper motor drives the lead screw to drive the comb to press the piece. When the comb reaches the predetermined stroke, the comb is pulled back, and the above cycle is repeated.

The action cycle of the auxiliary movement is that the sucker drops from the top of the silo, contacts the heat sink after the suction sheet, the sucker rises to the position and then moves to the top of the guide bit, the sucker goes down and opens the Haff comb with its linkage at the same time, releases the heat sink after the position, the sucker goes up and the Haff comb springs back, the sucker returns to the top of the silo, and so on.

Automatic assembly of main motion and auxiliary motion fragmentation and crosstalk are two independent and mutually restricted cycle processes. In order to improve the assembly efficiency, on the one hand, the operation speed needs to be fast, on the other hand, the coordination of the two operation cycles is to ensure the normal operation of the assembly machine, but also the key to improve the efficiency. The restriction relation is as follows: 1) the two cycle processes should be synchronized with the same cycle, and the short cycle cycle should be the same as the long cycle cycle; 2) The carding action can only be performed after the suction cup is returned, and the feeding action can only be performed after the end of the pressing.

Therefore, in order to reduce mutual influence, the coordination point of mutual restriction is adopted in the control. If the action conditions do not meet the cyclic action, they will stay at their own synchronization point and wait. Once the conditions are met, they will complete their own action cycle without interference. The main reason for the incoordination of the two operation cycles is that the cycle time of the operation decreases with the increase of the number of operation cycles, and the comb travel decreases with the increase of the number of operation cycles, so the required operation time is shortened. However, the cycle time of fragmentation is relatively stable. With the decrease of the number of heat sinks in the silo, the cycle time of fragmentation slightly increases. Therefore, in order to coordinate the work of the two and achieve the highest efficiency, finding the synchronization point is the key. In, the timing coordination points are respectively selected at the position of the lifting of the piece and the position of the pressing of the piece, that is, the serial piece cycle can only be inserted after the lifting of the piece. If the conditions are not met, wait; The fragmentation cycle can only be delivered smoothly after the tablet pressing is in place, otherwise wait at the waiting point. In the figure, T1 and T2 are respectively the waiting time of fragment cycle and sequence cycle, which constantly change with the assembly process. Normally, only one cycle needs to wait. At the start of the operation, both action cycles return to the zero position, the fragment cycle is completed first, and the cascade fragment cycle is triggered after the fragment is sent, and the whole cycle begins.

4 Conclusion

This research provides a good technical basis for the realization of radiator core automatic assembly machine and creates conditions for the flexible production of radiator. It can be predicted that after the successful development of radiator core automatic assembly machine, it will be able to adapt to the requirements of various types of core assembly piece spacing, solve the long-standing problems of core assembly piece spacing, ensure the assembly quality, and greatly reduce the labor intensity of workers.