JP2013137022A - Manufacturing method of tappet for engine valve train and tappet manufactured by the manufacturing method - Google Patents

Abstract

The lubrication characteristics of a cam and a tappet are improved, the wear resistance and the load resistance are increased, the time required for the tappet manufacturing process is shortened, and the manufacturing cost is reduced.
In a tappet manufacturing method, a tappet processed product is placed and fixed on a work table, a transfer device is controlled through a control device, and a laser oscillation device is formed on a cam contact surface of the tappet processed product with a lubricating groove pattern. A first step (S1) of arranging the laser oscillator at an appropriate position where it can be machined, and a laser oscillation device arranged at the machining position of the lubrication groove on the cam contact surface of the tappet at a transfer speed previously set in the control device. The second step (S2) for machining the lubrication groove of the pattern inputted in advance on the cam contact surface of the tappet by moving while irradiating the laser with the preset output and pulse, and the machining in the second step is completed A fifth step (S5) for removing burrs generated on the cam contact surface of the tappet is included.
[Selection] Figure 5

Description

  The present invention relates to a method of manufacturing a tappet for an engine valve train, and in particular, a lubrication groove using a laser processing equipment on a surface that contacts a cam of a tappet that opens and closes a valve by operating a rocker arm in conjunction with the rotational movement of the cam. The present invention relates to a method for manufacturing a tappet by forming a pattern.

  The present invention also relates to an engine valve train tappet having a lubricating groove pattern on a cam contact surface.

  In general, the valve train that opens and closes the valves of the engine opens and closes the intake and exhaust valves of each cylinder according to the timing when they are designed in the order of ignition. Depending on the valve arrangement and the shape of the combustion chamber, There are valve types, overhead valve (OHV) types, overhead camshaft (OHC) types, and the like.

  Among them, as shown schematically in FIG. 1, the overhead valve (OHV) is a push in which the valve 1 is provided on the cylinder head 2, the lower end is in contact with the cam 3, and the upper end is in contact with the rocker arm 5. The valve 1 opens and closes by the rod 4 moving up and down in conjunction with the rotational movement of the cam. A tappet 6 is provided at the lower end of the push rod that contacts the cam. Such a tappet plays a role of transmitting power to the rocker arm and the push rod by converting the rotational movement of the cam into a vertical movement.

  The tappet 6 comes into contact with the cam and transmits power to the push rod 4 and the rocker arm 5 to open and close the valve 1. At this time, the cam 3 and the tappet 6 come into contact with each other to perform frictional motion. However, it is important to minimize the friction loss between the tappet and the cam. This is because if the tappet is worn or damaged by friction with the cam, the accuracy of the valve operation is lowered, and further, the valve train itself cannot be operated and the multi-cylinder engine cannot be controlled. Therefore, it is very important to minimize friction loss without the tappet cam contact surface being worn or damaged.

  In the conventional technology for manufacturing the tappet, there is a method of increasing the strength by manufacturing the tappet by casting and forming a dense structure by bringing the chiller into contact with the cam contact surface in order to strengthen the cam contact surface. is there.

  However, this method has limitations in improving the tappet's wear resistance, friction resistance, and load resistance, and due to the high engine output due to continuous engine performance improvement and the deterioration of the engine operating environment due to high performance, There was a disadvantage that its use was limited.

  In order to solve such a problem, there is a tappet manufacturing method including a method in which a tappet base material is manufactured from a metal material such as cast iron or steel and the cam contact surface is subjected to heat treatment or coating.

  However, this method also has a disadvantage that it takes a lot of time and cost for the processing process of the tappet, and there is a problem that the friction resistance may be lowered depending on the coating method.

  In addition, a tappet base material is manufactured from a metal material such as cast iron or steel, and a tappet is manufactured by joining a hard metal to the cam contact surface. There is a disadvantage that much time and cost are required, and there is a disadvantage that the manufacturing process is complicated.

  The present invention has been made to solve the problems of the conventional tappet manufacturing method as described above, and an object of the present invention is to form fine lubrication grooves in a predetermined pattern on the surface of the tappet that comes into contact with the cam. It is an object of the present invention to provide a method for manufacturing a tappet with improved lubrication characteristics, wear resistance and load resistance of the cam and the tappet.

  Another object of the present invention is to provide an engine valve train tappet having a lubrication groove pattern preset on the cam contact surface by the above-described manufacturing method.

  A tappet manufacturing method according to the present invention for achieving the above object is a valve train tappet manufacturing method for opening and closing an engine valve. The tappet processed product is placed on a work table and fixed, and transferred through a control device. First step (S1) of controlling the apparatus to place the laser oscillation device at an appropriate position where the pattern of the lubricating groove can be processed on the cam contact surface of the tappet processed product. Lubricant groove with a pattern pre-input on the cam contact surface of the tappet by moving the laser oscillation device arranged at the machining position of the lubrication groove on the cam contact surface of the tappet at a speed while irradiating the laser with a preset output and pulse And a second step (S2) of machining the burrs generated on the cam contact surface of the tappet that has been machined in the second step. Comprising the step (S5) of.

  In the second step, it is preferable that the lubrication groove is processed by repeating laser irradiation so that the lubrication groove to be processed has a preset depth and pattern.

  The moving speed of the laser oscillation device is preferably the same as the moving speed when moving without irradiating the laser.

  Furthermore, the engine valve train tappet according to the present invention has a lubrication groove having a preset pattern, which is processed to a predetermined depth by the laser oscillation device by the above-described tappet manufacturing method, on the cam contact surface. Have.

  By producing a lubrication groove on the cam contact surface of the tappet that comes into contact with the cam according to the present invention, the lubrication characteristics of the cam and the tappet are improved, and the effect of increasing wear resistance and load resistance is obtained. Conventionally, the tappet manufacturing process time can be shortened and the manufacturing cost can be reduced as compared with the conventional technique of manufacturing the tappet by coating or heat-treating the cam contact surface of the tappet.

It is a schematic block diagram of the conventional engine valve train. It is a schematic block diagram of the laser processing equipment structure used for the manufacturing method of the tappet for engine valve trains of the present invention. 4 is an exemplary pattern of lubrication grooves formed on a cam contact surface of a tappet according to the present invention. 4 is an exemplary pattern of lubrication grooves formed on a cam contact surface of a tappet according to the present invention. It is a flowchart which shows the manufacturing method of the tappet which forms the lubrication groove | channel of the cam contact surface of the tappet for valve trains which concerns on this invention using the laser processing equipment of FIG.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing embodiments of the present invention.

  FIG. 2 schematically shows a configuration of a laser processing equipment used for forming a fine lubrication groove on the surface of the tappet in contact with the cam in the tappet manufacturing method according to the present invention.

  The laser processing equipment used in the present invention includes a laser oscillation device 10 that oscillates a laser so as to perform laser processing in a pattern required on the cam contact surface of the tappet, and lubrication that opposes the laser oscillation device 10 to the cam contact surface of the tappet. The transfer device 11 for transferring to the processing position of the groove, the work table 12 for placing and fixing the tappet, and the cooling and dust collecting device cool the laser oscillation device whose temperature has been increased while performing laser processing, A cooling / dust collecting device 13 for absorbing the generated harmful gas and dust, and a laser oscillation device 10 and a transfer device for working the lubricating groove with a pattern required for the lubricating groove on the cam contact surface of the tappet. 11 is input, and the laser generator 10 and the transfer device 11 are inputted by inputting processing conditions and pattern for laser processing the lubricating groove of the tappet with a desired pattern. A control unit 14 for controlling. The processing conditions include the output of the irradiated laser, the pulse width, the laser pause time, and the laser aperture value.

  The transfer device 11 is preferably moved on three straight lines so as to transfer the laser generator to a desired position, so that the laser generator can be moved to an accurate position in focus before processing, It is a device that assists machining while moving according to the transfer speed input to the control device 14. If necessary, the work table 12 or a part of the work table can be rotated.

  The laser generator 10 includes a laser oscillator, a lens, a mirror, and the like so as to generate a laser in accordance with the output and pulse controlled by the controller 14, and is moved according to the control of the controller 14.

  3 and 4 are exemplary views showing a pattern of lubricating grooves formed on the cam contact surface 20 of the tappet by the method of the present invention. The lubricating grooves 21 and the like are arranged in a dimple shape in a lattice pattern. It is preferable that the pattern is processed or a pattern in which the oblique grooves 22 and the like are arranged at regular intervals is not limited to such a pattern shape.

  FIG. 5 is a flowchart showing a method of forming a lubricating groove pattern on the cam contact surface of the tappet according to the present invention using the laser processing equipment.

  The tappet processed product for forming the lubrication groove by the tappet manufacturing method of the present invention is manufactured by casting and casting with cast iron material, and then processed and polished, but if necessary, it is made of steel or other alloy material The tappet material is not limited in the manufacturing method of the present invention.

  In the first step (S1) of the tappet manufacturing method according to the present invention, after the tappet processed product is placed on the work table 12 and fixed, the transfer device 11 is controlled through the control device 10 to control the laser oscillation device 10. Is arranged at an appropriate position where the lubricating groove pattern can be machined on the cam contact surface of the tappet processed product.

  In the second step (S2), the laser oscillation device 10 arranged at the machining position of the lubrication groove on the cam contact surface of the tappet is lasered with a preset output and pulse at a transfer speed previously inputted to the control device 14 and set. By moving while irradiating, one row of lubricating grooves having a pattern inputted in advance on the cam contact surface of the tappet is processed.

  In the third step (S3), after the processing of one row of the lubricating groove pattern is finished, the laser oscillation device 10 is moved to the processing start position of the next row of the lubricating groove pattern by the transfer device, and then the above-mentioned. The second step (S2) is repeated. The laser oscillation device 10 may be transferred by the transfer device, that is, a “self” shape, a zigzag shape, or another movement path. The transfer speed of the laser oscillation device is the same as the transfer speed when moving without irradiating the laser in the second step (S2).

  In the fourth step (S4), the entire lubrication groove on the cam contact surface of the tappet after the processing of each row of the lubrication groove pattern through the second step (S2) and the third step (S3) is completed. Then, while repeating the second and third steps, laser irradiation is performed to process a lubricating groove having a preset depth with a preset pattern. The number of repetitions of the second and third steps is preferably 1 to 5, and when such repeated processing is not performed, the bottom surface shape of the processed lubricating groove is non-uniform and the depth of the lubricating groove is uniform. When processing is performed more than 5 times, the amount of laser irradiation becomes excessive, and a lot of burrs are generated on the cam contact surface of the tappet, resulting in a problem that the processing surface is not smooth. In this case, it takes time to remove burrs in a fifth step, which will be described later, and the working efficiency decreases. Further, as the number of repetitions increases, there is a problem that the possibility of non-uniform lubrication groove shapes increases due to processing errors.

  The fifth step (S5) is a step of controlling (removing) burrs generated on the cam contact surface of the tappet that has been processed in the first to fourth steps. The burr generated by the processing in the first to fourth steps roughens the cam contact surface of the tappet, fills the lubrication groove processed by wear powder generated during the processing, and reduces the effect of the lubrication groove by half. Any method using ordinary polishing means such as sandpaper, polishing cloth, polishing liquid, etc. can be used for removing the burrs, but it is necessary that the lubricating grooves are not damaged during the removal of the burrs.

  As described above, a tappet manufactured by forming a lubrication groove having a predetermined pattern on the cam contact surface of the tappet using a laser processing equipment is compared with the conventional technology in which coating or heat treatment is performed on the cam contact surface of the tappet. , Have more improved lubrication properties and wear resistance.

  The tappet manufacturing method according to the present invention is conventionally used for an engine valve train so that lubrication characteristics and wear resistance can be improved more efficiently on the cam contact surface of the tappet, instead of coating or heat treatment on the cam contact surface. It can be applied to a tappet manufacturing method.

10: Oscillator, 11: Transfer device, 12: Work table, 13: Cooling / dust collecting device, 14: Control device.

Claims (4)

In a valve train tappet manufacturing method for opening and closing an engine valve,
The tappet processed product is placed and fixed on the work table 12, and the transfer device 11 is controlled through the control device 14 so that the laser oscillation device 10 can process the lubricating groove pattern on the cam contact surface of the tappet processed product. A first step (S1) of arranging at a position;
By moving the laser oscillation device 10 disposed at the processing position of the lubrication groove on the cam contact surface of the tappet at the transfer speed set in advance by inputting to the control device 14 while irradiating the laser with the preset output and pulse. A second step (S2) of machining a lubricating groove having a pattern inputted in advance on the cam contact surface of the tappet;
A fifth step (S5) for removing burrs generated on the cam contact surface of the tappet that has been processed in the second step;
A method for manufacturing a tappet for an engine valve train including   2. The engine valve train according to claim 1, wherein in the second step, the lubrication groove is processed by repeating laser irradiation so that the lubrication groove to be processed has a preset depth and pattern. 3. For manufacturing tappets.   The method of manufacturing a tappet for an engine valve train according to claim 1, wherein the moving speed of the laser oscillation device 10 is the same as the moving speed when moving without irradiating a laser. A tappet for an engine valve train manufactured by the manufacturing method according to any one of claims 1 to 3.