Processing technology of rocker shaft

Abstract

The present invention discloses a processing technology for a rocker shaft, comprising the following steps: step one: precision casting a blank of the rocker shaft; step two: placing the rocker shaft blank into a mold and cold heading the transmission pin on the rocker shaft through a cold heading machine; step three: heat treating the end face of the rocker shaft body facing the transmission pin and the outer surface of the transmission pin. Due to the use of mold cold heading shaping, not only can the mechanical properties and load-bearing capacity of the transmission pin be greatly improved, but also the shape and position accuracy and consistency of the transmission pin can be improved, so that all the transmission pins can evenly share the impact load from the tool head, thereby extending the service life of the transmission pin by several times or even dozens of times; and due to the one-time forming by the cold heading process, the processes of marking, drilling, cutting, assembly, and inspection in the prior art are omitted, and the transportation of semi-finished products between the processes can also be omitted, thereby greatly reducing the manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electric tools, and more particularly to a processing technology for a Wanyongbao rocker shaft. Background Art

[0002] The electric tool multi-function tool, also known as the all-purpose tool, was invented by Harmonics of Germany in 1967. It relies on a rocker shaft to drive tool heads such as spatulas, saw blades, and angle grinders to swing in small amplitude and high frequency, thereby achieving multifunctional operations such as grinding, cutting, scraping, filing, polishing, etc. It is widely used in medical, home improvement, woodworking DIY, car factories, shipyards and other fields.

[0003] The working principle of Wanyongbao is as follows Figure 1 As shown, the motor drives the eccentric shaft to rotate, the bearing on the eccentric shaft drives the swing plate to swing, the swing plate drives the rocker shaft fixedly connected to the rocker shaft to swing back and forth at a small angle, and the rocker shaft drives the tool head locked on the rocker shaft and exposed at the head of the shell to swing. The operator selects the corresponding tool head to perform the corresponding operation according to the nature of the work.

[0004] The connection between the rocker arm shaft and the tool head is achieved as follows: a fixing hole is provided on the tool head, and six to twelve pin holes are evenly distributed on the concentric circle of the fixing hole; the head of the rocker arm shaft exposed from the shell is a retaining ring part, and the outer end face of the retaining ring part is provided with four to six transmission pins matching the pin holes of the tool head, and a locking shaft is provided in the rocker arm shaft, and the locking shaft is provided with an external thread on the outer side of the retaining ring part of the rocker arm shaft; the pin hole on the tool head is sleeved on the transmission pin of the retaining ring part, and then the tool head is fixedly connected to the rocker arm shaft by screwing the nut pressure plate through the external thread of the locking shaft or by the action of the locking spring.

[0005] In the prior art, the processing technology of the tool head is: the punch press uses a mold to punch and form it in one go; the processing technology of the transmission pin on the rocker shaft is: 1. Use a line on the outer end face of the retaining ring to locate the processing position of all the through holes for installing the transmission pins, 2. Use a drilling machine to drill all the through holes in sequence, 3. Check whether the size tolerance and position tolerance of the through holes are qualified, 4. Use a lathe to turn all the transmission pin blanks into a cylinder and chamfer one end, 5. Use a lathe to turn the other end of all the transmission pins into a truncated cone shape, 6. Check whether the size tolerance and taper tolerance of the cylindrical part and the truncated cone part of the transmission pin are qualified, 7. Use a hammer to hammer all the transmission pins processed in the third step into the through holes, 8. Check whether the verticality tolerance of the transmission pin installation is qualified.

[0006] The tool head and the rocker shaft are both wearing parts. From the working principle of the above-mentioned multi-purpose tool and the connection relationship between the rocker shaft and the tool head, it can be seen that the dimensional tolerance and form and position tolerance between the pin hole on the tool head and the transmission pin on the rocker shaft retaining ring are very important. It can be seen from the processing technology of the pin hole in the prior art that the pin hole of the tool head is punched and formed in one time, which is a stamping part. The stamping die is used to ensure the size and shape of the pin hole on the tool head, which is relatively accurate; it can be seen from the processing technology of the transmission pin in the prior art that the marking and positioning in step 1 are completed manually, and positioning deviations are inevitable. As for the drilling machine processing in step 2, we know that the drilling accuracy of the drilling machine is not high, and deviations in the size and shape of the drilled holes are also inevitable. Therefore, it is inevitable that the qualified rate detected in step 3 is low. In steps 4 and 5, each transmission pin needs to be clamped 2 times and turned 3 times, and the work efficiency is low. In step 6, the outer diameter, cone taper and coaxiality of the transmission pin need to be inspected, and the work efficiency is low. In step 7, it is difficult to ensure the verticality of the transmission pin relative to the outer end face of the retaining ring by hammering manually. Therefore, it is inevitable that the qualified rate detected in step 8 is low. In summary, the processing technology of transmission pins in the prior art not only has many processing steps, low processing efficiency, high labor intensity for operators, and low product qualification rate, but also has poor consistency among the multiple transmission pins on the rocker shaft due to dimensional errors and geometric errors of the transmission pins. As a result, each transmission pin is subjected to a different dynamic load when transmitting power. We know that the speed of the Wanyongbao motor is as high as 20,000 to 30,000 revolutions per minute. That is to say, the tool head swings in one direction and completes the reverse swing in about one ten-thousandth of a second. The impact force of the steering inertia of the tool head swinging can be imagined. Coupled with the impact load generated during operation, such a large impact load is borne by a few transmission pins. Obviously, it will not take long for the transmission pin subjected to the heaviest impact load to be damaged and fail. The impact load will naturally be transferred to the transmission pins that are still intact. When all the transmission pins fail in turn due to being unable to withstand the huge impact load of the tool head swinging and steering inertia, the rocker shaft will naturally fail as well. Therefore, the poor consistency of the multiple transmission pins on the rocker shaft will significantly shorten the service life of the rocker shaft. Summary of the Invention

[0007] In order to overcome the above-mentioned defects, the technical problem to be solved by the present invention is: to provide a processing technology for a rocker shaft with fewer processing steps and good transmission pin consistency.

[0008] The present invention solves the problems existing in the prior art by providing a technical solution: a processing technology for a rocker shaft, comprising the following steps:

[0009] Step 1: Precision casting the blank of the rocker shaft;

[0010] Step 2: Place the swing arm shaft blank into the mold and use a cold heading machine to cold-forge the transmission pin on the swing arm shaft;

[0011] Step 3: Heat treat the end surface of the rocker shaft body facing the transmission pin and the outer surface of the transmission pin.

[0012] In step 2 of the technical solution of the present invention, since a mold is used to perform cold forging and shaping through a cold forging machine, the volume of the metal is redistributed and transferred, and the internal structure of the metal is compacted, which can eliminate defects such as loose casting of the metal structure produced during the casting process, optimize the microstructure, and at the same time preserve the complete metal streamlines, which can greatly improve the mechanical properties and load-bearing capacity of the transmission pin; and since a mold is used to perform cold forging and shaping, the mold can ensure the shape and position accuracy and consistency of all the transmission pins on the rocker shaft, so that all the transmission pins can evenly share the impact load from the tool head; based on the above two combined beneficial effects, the service life of the transmission pin can be extended by several times or even dozens of times.

[0013] In step 2 of the technical solution of the present invention, since the cold heading process is used for one-time forming, the processes of marking, drilling, cutting, assembly, and inspection in the prior art are omitted. At the same time, the transportation of semi-finished products between the various processes can also be omitted. Therefore, labor productivity can be greatly improved, labor costs can be greatly reduced, the labor intensity of operators can be reduced, the working conditions of operators can be improved, energy can be saved, and equipment use costs can be reduced. In addition, since the cold heading process is a non-cutting process, the material utilization rate is very high, which can reduce material costs.

[0014] As a further technical solution, after step 2 and before step 3, a machining device is used to remove the overflow portion at the front end of the rocker shaft transmission pin.

[0015] The mold includes an upper mold and a lower mold. The upper mold is provided with a first blind hole on one end surface facing the lower mold, and the first blind hole can accommodate the locking part on the rocker shaft. The closed end surface of the first blind hole is also provided with a second blind hole, and the second blind hole can accommodate the unlocking part on the rocker shaft. The lower mold is provided with a third blind hole on one end surface facing the upper mold, and the third blind hole can accommodate the retaining ring part on the rocker shaft. The closed end of the third blind hole is provided with multiple fourth blind holes, and the fourth blind holes can accommodate and shape the transmission pin of the rocker shaft.

[0016] As a further technical solution, an overflow trough is provided at the closed end of the fourth blind hole to accommodate excess material generated during the shaping of the drive pin. Because defects such as as-cast porosity in metal structures during the casting process are difficult to predict, a slight allowance is necessary. Any excess material that does occur during cold heading and extrusion shaping can flow into the overflow trough to ensure precise positioning of the rocker shaft.

[0017] As a further technical solution, the bottom surface of the overflow trough is provided with a vent hole. The vent hole is provided to facilitate the redistribution and transfer of the metal volume, and to eliminate the gas generated when the metal structure is loosened during the casting process, so as to prevent the gas from being retained in the metal and causing defects.

[0018] As a further technical solution, the number of the fourth blind holes is six, and the axes of the six fourth blind holes are evenly distributed on the concentric circles of the third blind hole.

[0019] As a further technical solution, the heat treatment is carbonitriding with a penetration depth of 0.2 to 0.3 mm and a surface hardness of HRC54~56.

[0020] The beneficial effects of the present invention are as follows: since the mold is used for cold heading shaping, not only the mechanical properties and load-bearing capacity of the transmission pin can be greatly improved, but also the shape and position accuracy and consistency of the transmission pin can be improved, so that all the transmission pins can evenly share the impact load from the tool head, thereby extending the service life of the transmission pin by several times or even dozens of times; and since the cold heading process is used for one-time forming, the marking, drilling, cutting, assembly, inspection and other processes in the prior art are omitted, and the transportation of semi-finished products between each process can also be omitted, thereby greatly reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural cross-sectional diagram of Wanyongbao;

[0022] Figure 2 is a schematic cross-sectional view of the rocker shaft of the present invention;

[0023] Figure 3 1 is a bottom view schematic diagram of the rocker shaft in the present invention;

[0024] Figure 4 It is a cross-sectional schematic diagram of the upper mold of the mold in the present invention;

[0025] Figure 5 It is a cross-sectional schematic diagram of the lower mold of the mold in the present invention;

[0026] Figure 6 It is a top view schematic diagram of the lower mold of the mold in the present invention.

[0027] In the figure: rocker shaft 1, unlocking part 2, transmission pin 3, retaining ring part 4, locking part 5, upper die 6, second blind hole 7, first blind hole 8, lower die 9, fourth blind hole 10, third blind hole 11, exhaust hole 12, overflow chute 13. DETAILED DESCRIPTION

[0028] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0029] Embodiment: A processing technology of a rocker shaft, the rocker shaft 1 is as follows Figure 2 、 Figure 3 As shown, it includes a retaining ring portion 4 located at one end of the rocker shaft 1 and an unlocking portion 2 located at the other end of the rocker shaft 1, a locking portion 5 is provided between the retaining ring portion 4 and the unlocking portion 2, and six transmission pins 3 are provided on the outward end surface of the retaining ring portion 4, and the axes of the six transmission pins 3 are evenly distributed on the concentric circles of the retaining ring portion 4, and the unlocking portion 2, the locking portion 5, the retaining ring portion 4, and the six transmission pins 3 are connected as a whole.

[0030] The mold used for cold heading shaping of the rocker shaft 1 is as follows: Figure 4 、 Figure 5 、 Figure 6 As shown, it includes an upper mold 6 and a lower mold 9, and the upper mold 6 is provided with a first blind hole 8 on one end surface facing the lower mold 9, and the first blind hole 8 can accommodate the locking part 5 on the rocker shaft 1, and the closed end surface of the first blind hole 8 is also provided with a second blind hole 7, and the second blind hole 7 can accommodate the unlocking part 2 on the rocker shaft 1, and the lower mold 9 is provided with a third blind hole 11 on one end surface facing the upper mold 6, and the third blind hole 11 can accommodate the retaining ring part 4 on the rocker shaft 1, and the closed end of the third blind hole 11 is provided with a plurality of fourth blind holes 10, and the fourth blind holes 10 can accommodate and shape the transmission pin 3 of the rocker shaft 1, and the number of the fourth blind holes 10 is six, and the axes of the six fourth blind holes 10 are evenly distributed on the concentric circle of the third blind hole 11, and the closed end of the fourth blind hole 10 is provided with an overflow groove 13, and the overflow groove 13 can accommodate excess material generated when shaping the transmission pin 3, and the bottom surface of the overflow groove 13 is provided with an exhaust hole 12.

[0031] The processing technology of the rocker shaft 1 includes the following steps:

[0032] Step 1: Precision casting the blank of the rocker shaft 1. The volume of the base blank for cold heading the transmission pin 3 on the blank of the rocker shaft 1 is slightly larger than the volume of the transmission pin 3.

[0033] Step 2: Place the swing arm shaft 1 blank into the mold and use a cold heading machine to cold-forge the transmission pin 3 on the swing arm shaft 1, and then use machining equipment to remove the overflow part at the front end of the transmission pin 3 of the swing arm shaft 1;

[0034] Step 3: Heat treatment is performed on the end face of the rocker shaft 1 body facing the transmission pin 3 and the outer surface of the transmission pin 3. The heat treatment is carbonitriding with a penetration depth of 0.2 to 0.3 mm and a surface hardness of HRC54~56.

[0035] The embodiment described above is only a preferred solution of the present invention and does not limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solution described in the claims.

[0036] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A processing technology for a rocker shaft, wherein the rocker shaft comprises a retaining ring portion located at one end of the rocker shaft and an unlocking portion located at the other end of the rocker shaft, a locking portion is provided between the retaining ring portion and the unlocking portion, a plurality of transmission pins are provided on the outward end surface of the retaining ring portion, the axes of the plurality of transmission pins are uniformly distributed on the concentric circle of the retaining ring portion, and the unlocking portion, the locking portion, the retaining ring portion, and the plurality of transmission pins are connected as a whole; characterized in that: The mold for cold forging and shaping the rocker arm shaft comprises an upper mold and a lower mold, wherein the upper mold is provided with a first blind hole matching the locking portion on one end surface facing the lower mold, and a second blind hole matching the unlocking portion on the closed end surface of the first blind hole, and the lower mold is provided with a third blind hole matching the retaining ring portion on one end surface facing the upper mold, and a fourth blind hole matching a plurality of drive pins on the closed end of the third blind hole, and an overflow groove is provided on the closed end of the fourth blind hole, and the overflow groove can accommodate excess material generated when shaping the drive pins, and an exhaust hole is provided on the bottom surface of the overflow groove; Processing technology of the rocker shaft: Step 1: Precision casting the blank of the rocker shaft. The volume of the base blank for cold heading the transmission pin on the rocker shaft blank is larger than the volume of the transmission pin; Step 2: Place the swing arm shaft blank into the mold and use a cold heading machine to cold-forge the transmission pin on the swing arm shaft; Step 3: Heat treat the end surface of the rocker shaft body facing the transmission pin and the outer surface of the transmission pin.

2. The processing technology of the rocker shaft according to claim 1, characterized in that: After step 2 and before step 3, use machining equipment to remove the overflow portion at the front end of the rocker shaft transmission pin.

3. The processing technology of the rocker shaft according to claim 1 or 2, characterized in that: The number of the fourth blind holes is six, and the axes of the six fourth blind holes are evenly distributed on the concentric circles of the third blind hole.

4. The processing technology of the rocker shaft according to claim 1, characterized in that: The heat treatment is carbonitriding with a penetration depth of 0.2 to 0.3 mm and a surface hardness of HRC54-56.

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