JP3843445B2 - Method for remelting camshaft - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a camshaft remelting method for remelting a cam surface by using a high-density energy heat source in order to form a hardened chilled structure on the cam surface.
[0002]
[Background of the present invention]
It has been conventionally known that the cam surface is remelted and then cooled to form a chilled layer having a predetermined thickness and high hardness on the cam surface portion, thereby improving the wear resistance of the cam. In this method, in order to remelt the cam surface, a TIG torch or a plasma torch is used, and the torch is used as one electrode and the cam side is used as the other electrode. Then, an arc as a high-density energy heat source is generated on the cam surface to be processed with the torch, and the cam surface is irradiated with the arc to remelt the cam surface.
In this method, when the arc is irradiated onto the cam surface, the camshaft is rotated to sequentially advance the arc irradiation area in the rotation direction.
[0003]
It is desirable to form a remelting region with a uniform depth over the entire sliding surface of the cam surface. However, since the irradiation range of the torch is narrower than the cam surface width, the camshaft is not used in the remelting process. While rotating, the arc is irradiated over the entire width so as to oscillate, that is, swing, the torch from side to side.
Normally, a single camshaft is provided with a plurality of cams, and the remelting process is performed on each of them by applying a remelting apparatus. In this case, generally, a pair of remelting apparatuses is provided in one station, and a pair of camshafts are introduced into the remelting station. A pair of remelting devices operate simultaneously on the pair of camshafts introduced into the remelting station to perform the remelting process. When the remelting process of the pair of cams is completed, the camshaft is sent to the next station, and another pair of cams on the paired camshafts is similarly remelted using the pair of remelting processing devices. Process.
[0004]
Therefore, in the case of a four-cylinder engine, since eight cams are formed on one camshaft, the remelting process is performed over four stations.
In this case, when a problem occurs regarding the finish of the remelting process of the cam, depending on the state, the remelting apparatus may cause the problem.
In such a case, it is necessary to determine which remelting processing apparatus has performed the processing, but it is difficult to determine from the camshaft.
In this case, for example, if the work is marked as disclosed in Japanese Patent Laid-Open No. 9-203344, the apparatus can be located afterwards.
[0005]
[Problems to be solved]
However, as disclosed in the above publication, if the work, that is, the camshaft is marked, it is necessary to install a marking device, which increases not only the cost of installing the device but also the man-hours. Efficiency decreases.
In particular, immediately after the remelting process, the temperature is around 100 ° C., so it is necessary to check whether the remelting process is appropriate or not. It is difficult to know the situation accurately. In addition, when machining is added in the subsequent process, it is difficult to accurately pursue processing accuracy.
[0006]
[Means for Solving the Problems]
The present invention is configured in view of such circumstances, and it is possible to easily associate the cam and the apparatus related to the remelting process with a simple method without reducing the workability of the remelting process. An object of the present invention is to provide a remelting method that can be performed.
This object of the present invention is to provide a remelting process in which all the remelting devices for a plurality of cams on a single camshaft are not common when the cam surface of a camshaft provided with a plurality of cams is remelted. In the method
Introducing the camshaft into the remelting station,
Remelting a predetermined cam on the camshaft using a predetermined remelting apparatus,
And with the associating marking a cam and re-melting treatment apparatus according to the remelting process on the camshaft with re-melting treatment apparatus was subjected to re-melting process of the predetermined cam before moving to the next step ,
This is achieved by making the marking into a remelted chill layer formed on the base circle of the cam by a remelting process.
After the remelting process, the cam surface is usually subjected to a process referred to as a luebright process. In the present invention, this portion is used for marking.
This treatment also forms a phosphate film on the cam surface to reduce the surface frictional resistance. When this process is performed, the surface of the chilled cured layer formed by the remelting process is different from the surface on which the chilled layer is not formed, so that the discrimination is possible.
[0007]
In this case, the marking can be a shoulder formed on the shoulder of the base circle of the cam by the remelting process. The base circle is normally not required to function as a cam and does not need to be remelted.
Therefore, there is no real harm even if a shoulder is caused in this part.
[0008]
In a preferred embodiment of the present invention, the marking is applied to the cam surface area adjacent to the area to be remelted. In this way, marking can be easily performed, and correspondence between the cam and the remelting apparatus that has processed the cam can be easily performed.
Furthermore, after the normal remelting process, the marking may be attached to a predetermined position spaced from the remelting process area. By doing in this way, the remelting process concerning another apparatus can be distinguished.
[0009]
【Example】
Hereinafter, the present invention will be described based on examples.
Referring to FIG. 1, an overall view of an apparatus related to a camshaft remelting process according to an embodiment of the present invention is shown in a plan view along a conveying direction.
In this example, the camshaft subjected to the remelting process is a camshaft of a four-cylinder engine, and four intake cams and exhaust cams are formed corresponding to the four cylinders.
In order to perform the remelting process of the camshaft, four processing stations are provided on the transfer line. Then, two camshafts 1 and 2 are fed into the transport line for processing, and a pair of cams are processed at each of the four stations.
[0010]
The remelting process line is arranged along the conveying direction in the carrying-in station 3, the vehicle type identification station 4, the first preheating station 5, the second preheating station 6, the first processing station 7, the first standby station 8, and the second processing station. 9, a third processing station 10, a second standby station 11, a fourth processing station 12, and an unloading station 13 are provided. And the pit 14 is formed in the conveyance direction on the floor.
A pair of front and rear work receiving members 15 are provided at the transfer station 3, the first and second standby stations 8 and 11, and the carry-out station 13 so as to face the pit 14. The vehicle type identification station 4 is provided with a vehicle type identification device 18 having a pair of support mechanisms 16 and an identification mechanism 17. The first and second preheating stations 5 and 6 are preheated with a pair of preheaters 19 and 20, respectively. Devices 21 and 22 are provided. The first to fourth remelting treatment stations 7, 8, 9, 10 are provided with torches 23, 24, a torch moving device, and a camshaft rotating device.
[0011]
The pit 14 is provided with a conveying device for sequentially conveying the pair of camshafts 1 and 2 from each station to the station. The conveying device is provided in a control panel 26, which is provided in a control panel 26, which is disposed in a pit and is arranged in a pit and is driven in a cycle with a predetermined stroke. It is controlled by the controller 27.
A pair of camshafts are carried into the carry-in station 3 from the camshaft production line by an autoloader. The camshafts 1 and 2 are supported by the workpiece receiving member 15, and after the processing is completed, the camshafts 1 and 2 are tact-conveyed to the next station by the carrier 25 at a predetermined timing.
In the vehicle type identification station 4, the camshafts 1 and 2 are supported by the support mechanism 16 and, for example, the nose portion of the intake cam of the first cam portion is directed vertically downward to a predetermined reference rotational position. The rotational phase is adjusted. At this reference rotational position, an applicable vehicle vehicle type identification mark is detected. In the first preheating station 21, the preheater 19 is heated to a predetermined temperature of, for example, about 200 ° C. over a predetermined time. Further, in the second preheating station 22, it is heated to, eg, 400 ° C. over a predetermined time.
[0012]
Then, it is carried into the first processing station 7 and remelted. In the first processing station 7, the intake cam and the exhaust cam of the first cam portion are remelted.
Then, in the second to fourth processing stations 9, 10 and 12, the intake and exhaust cams of the second to fourth cam portions are sequentially remelted.
In this manner, when the eight cams, that is, the intake cams and the exhaust cams of the first cam to the fourth cam are remelted through the first to fourth processing stations, the pair of camshafts are moved from the carry-out station to the engine. It is carried out to the assembly line. The first and second standby stations 8 and 11 are provided for temporarily waiting the camshaft when the line is stopped.
Further, FIG. 2 shows a side view of the remelting processing apparatus 28 disposed in each of the processing stations 7, 9, 10, and 12.
[0013]
The remelting processing device 28 of this example includes a torch moving device 29 and a pair of TIG torches 23 (24) that generate an arc as a high-density energy heat source provided in the torch moving device 29. In this example, an electric circuit is configured such that the TIG torch 23 (24) is a negative electrode and the camshaft 3 is a positive electrode, and between the TIG torch 23 (24) and the cam surface of the cam of the camshaft 2 An inert gas atmosphere such as argon is formed to cause arc discharge.
Then, the cam surface is remelted using the high-density energy generated by the arc discharge as a heat source. Thereafter, it is cooled to form a hardened chilled structure.
Further, the remelting processing device 28 includes a temperature detector 30, a rotation support device 31 that supports shaft portions at both ends of the camshaft, and a torch power supply unit 32 that supplies the arc generating power to the torch. . As described above, the control panel 26 includes the control unit 27 that controls the four remelting apparatuses. Furthermore, a hydraulic pressure supply device 33 that supplies hydraulic pressure for driving the torch moving device 31 and the like is provided.
[0014]
The rotation support device is disposed in opposition to the hydraulic cylinder 34 disposed behind the pit 14, a support shaft member coupled to the rod of the hydraulic cylinder 34 via a guide member, and in front of the pit. A hydraulic cylinder 35, a servo motor 36 connected to a rod of the hydraulic cylinder via a guide member, and a holder 37 provided at an output shaft end of the servo motor 36 are provided.
The support member, the servo motor 36 and the holder 37 can be switched between a forward position and a backward position by a hydraulic cylinder 35. The holder has three sets of gripping portions, and these gripping portions can be switched between a gripping portion and a non-grip portion by the action of a hydraulic cylinder.
The torch moving device 29 includes an apparatus main body and an arm 38 projecting forward from the main body, and supports the torch by a servo motor that reciprocates the arm in the front-rear direction, a servo motor that reciprocates in the vertical direction, and the tip of the arm. A supporting member is provided.
[0015]
As shown in FIG. 3, the temperature detection device for forming the temperature of the cam surface is attached in the vicinity of the torch. The temperature detection device 30 is of an infrared type that incorporates a vapor deposition thermopile as a detection element.
When irradiating the cam surface 41 from the TIG torch 23, the camshaft 1 is rotated, whereby the arc irradiation area to the cam surface 41 of the cam 40 is sequentially sent. Further, since the TIG arc irradiation width of the TIG torch 23 is smaller than the cam width, the TIG torch 23 is oscillated, that is, oscillated in the width direction of the cam surface 41 in order to form a molten region uniformly over the entire width of the cam surface 41.
As a result, the TIG torch 23 forms the melting region 6 while drawing a meandering oscillating locus as shown by the line A in the figure on the rotating cam surface.
[0016]
In this case, the chill structure is preferably formed over the entire cam surface from the viewpoint of cam wear resistance.
For this purpose, it is desirable to swing the torch 23 so that the width of the oscillate is as close as possible to the width of the cam 40.
In this example, after the normal remelting process is completed, the remelting apparatus irradiates the base circle 42 of the cam 40 with an arc using the torch 23 as shown in FIG. Cause it to occur.
In this case, in order to indicate that the remelting process has been performed by the first remelting apparatus in the first processing station, the intentional shoulder is placed on one side on the right side of the base circle 42 of the processed cam. Marking is performed by a drape 43.
[0017]
As described above, in the remelting process, the torch 23 can arbitrarily move on the cam surface in the rotational direction and the width direction. Therefore, after the normal remelting process is performed, the rotation on the cam with respect to the remelting processing device 28 in the control unit 27 is performed in advance so that irradiation for the intended shoulder sag 43 is performed at a predetermined position. What is necessary is just to set and set a position and a horizontal position. This is generally easy because it is a program operation.
In this example, two torches 23 and 24 are provided in each of the processing stations 7, 9, 10 and 12, and there are a total of 8 torches in the remelting processing station. Therefore, in order to specify which torch has performed the remelting process of the cam, it is sufficient to perform eight kinds of markings in total.
[0018]
As shown in FIG. 4, there are four different parts in total at two locations (for example, 120 ° and 240 ° from the nose top) at different positions on the base circle with respect to the cam rotation direction, and two on the left and right sides with respect to the width direction By generating the shoulder sag 43 and performing marking, eight or more types of marking can be performed. For example, by performing marking as shown in FIG. 5 corresponding to eight cams, it is possible to determine afterwards which torch of which station has remelted each cam.
In this way, for each camshaft, it is possible to accurately grasp the relationship between the cam finish and the remelting processing equipment, which improves the performance of the remelting process and stabilizes the high-quality chill curing. It is very important for producing camshafts 1, 2 with layers.
[0019]
This is particularly true when the remelting processing is performed on the cam surface of the camshaft provided with a plurality of cams as in this example, and the remelting processing devices for the plurality of cams on one camshaft are all in common. This is important when performing a remelting process that should not be performed.
That is, when all the remelting apparatuses are inspected due to defects in the finish of a specific cam, the working efficiency is significantly reduced.
In this regard, in the present invention, if it is found after the remelting process that the remelting process is not properly performed by checking a specific cam of the camshaft, the cam remelting apparatus is immediately used. I can find out. This is because the optimum operation state of the apparatus can be quickly recovered by checking only the apparatus related to the remelting process.
[0020]
In this case, improvement of the sliding characteristics of the cam is required in the chilled region 45 formed in the nose portion, and the base circle portion 42 is not required to function as a cam and is remelted. There is no need to perform processing, and even if a shoulder is caused in this part, there is no actual harm.
FIG. 6 shows another embodiment of the present invention. In this example, after the normal remelting process, marking is performed on the base circle portion 42 of the cam using the remelting apparatus 28 as in the previous example. However, in this example, as described above, It does not cause anyone to remelt. That is, the same processing as that for forming a normal chilled structure is performed.
Thereafter, a process of forming a phosphate film on the cam surface, which is called a luebright process, is performed on the camshafts 1 and 2.
[0021]
When this treatment is performed, the color of the surface on which the chilled structure is formed and the other parts are different, and therefore the chilled structure portion 44 can be visually distinguished. Therefore, as described above, two marking positions in the rotation direction and two marking positions in the width direction are set in the base circle portion of the cam surface, and the remelting process is performed to form a chilled structure in this portion. As a result, the same effect as the marking by the shoulder sag in the previous example can be obtained.
In this example, since it is formed on the cam surface, there is an advantage that it does not appear at all on the exterior unlike the shoulder. In addition, by setting two markings in the rotation direction and two markings in the width direction, it is possible to distinguish up to 24 remelting processes. The remelting processing apparatus and the cam can be associated with virtually any aspect.
[0022]
【The invention's effect】
According to the present invention, it is possible to reliably associate the remelted cam with the remelting processing apparatus by an extremely simple operation as described above, and to easily find a defect in the remelting process. At the same time, quick response is possible. Even if there is a malfunction of the device, it can be recovered quickly and the optimum operation can be recovered. Moreover, since management for each apparatus becomes possible, the reliability of the measuring instrument of another remelting apparatus is not impaired. Also, good results can be obtained in terms of worker safety. According to the present invention, even when the camshaft is machined in a process after the remelting process, it can be associated with a reliable remelting apparatus, and the quality of the remelting process is reliably improved. Can be made.
[0023]
As a result, it is possible to stably provide a camshaft having a good quality chilled structure.
[Brief description of the drawings]
FIG. 1 is an overall view showing a remelting processing apparatus according to an embodiment of the present invention in the form of a plan view;
FIG. 2 is a side view of one remelting apparatus in the remelting apparatus of FIG.
FIG. 3 is a perspective view showing a state of a remelting process,
FIG. 4 is an explanatory view showing a marking position;
FIG. 5 is a relationship diagram showing types of markings;
FIG. 6 is an explanatory diagram showing a marking position according to another embodiment.
[Explanation of symbols]
1, 2 Camshaft 3 Loading station 7, 9, 10, 12 Remelting processing station 23, 24 Torch 28 Remelting processing device 43, 44 Marking.

Claims (1)

In the remelting processing method in which all the remelting processing devices for a plurality of cams on a single camshaft are not common when remelting the cam surface of a camshaft provided with a plurality of cams,
Introducing the camshaft into the remelting station,
Remelting a predetermined cam on the camshaft using a predetermined remelting apparatus,
And with the associating marking a cam and re-melting treatment apparatus according to the remelting process on the camshaft with re-melting treatment apparatus was subjected to re-melting process of the predetermined cam before moving to the next step ,
A camshaft remelting process comprising a step of forming a phosphate film on the cam surface, wherein the marking is a remelted chill layer formed on the base circle of the cam by the remelting process Method.

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