JPH0366110B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a connecting rod that is fitted into the pin portion of a crankshaft of a reciprocating engine in two parts and tightened with a bolt or nut, and a processing of the bearing surface of the cap that comes into contact with the bolt or nut. It is about the method.

B. Prior Art A connecting rod A consisting of a small end that connects to a piston pin of a reciprocating engine piston, a big end that connects to a pin portion of a crankshaft, and a rod that connects the small end and the big end is shown in Fig. 1. As shown in the figure, the connecting rod body a has the small end, rod and big end halves integrated.
and cap b, which is the other half of the big end.

When connecting the connecting rod A consisting of the above two members to the pin portion of the crankshaft, the pin portion of the crankshaft is fitted into the connecting rod body a and the cap b, and the bolt c and nut d are inserted. By using the connecting rod main body a and the cap b, the crankshaft and connecting rod A are connected.
are connected.

When a reciprocating engine, in which the piston and crankshaft are connected by the connecting rod A described above, is installed in a car, for example, when the car is running, loads caused by road surface conditions, vibrations, and loads caused by the rotation of the engine itself are absorbed. Random or periodic fluctuating loads and vibrations are applied to the bolts c and nuts d for tightening the connecting rod body a and its cap b. Therefore, the bolts c and nuts d have varying stresses caused by tension and vibration corresponding to random or periodic varying loads and vibrations.

Therefore, the connecting rod main body a and the cap b are formed on the connecting rod body a and the cap b, which are fixed in contact with the tightening surfaces of the bolts c and nuts d, and the bearing surfaces e, which serve as contact pressure receiving surfaces,
If the surface roughness of f is rough and there are peaks and valleys in the micron scale on the seating surfaces e and f, the peaks of the seating surfaces e and f will be crushed over time due to the "beating action". The height of the mountains decreases. If this amount exceeds the elongation occurring in the bolt c, the contact pressure on each contact surface will disappear.

In addition, the axial clearance between the threaded pairs of normal bolts and nuts used to tighten two members is
It is generally a matter of course that they exist for removal and manufacturing reasons, and it is not common to pair them tightly due to various disadvantages. The threaded pair of the bolt c and nut d that fasten the connecting rod main body a and its cap b is also of the type with a gap.

Therefore, if the contact pressure is lost due to the above-mentioned "struck action" and a gap is generated between the bolt c and the nut d, the fluctuating load and vibrations applied to the bolt c and the nut d will cause the bolt c to Also, the nut d may become loose.

The following two methods can be considered as methods for eliminating the above drawbacks.

The first method is to reduce the surface roughness of the seating surfaces e and f formed on the connecting rod body a and its cap b, which are fixed in contact with the tightening surfaces of the bolts c and nuts d, as much as possible. Finely finished, seat surfaces e and f
Lower the height of the peaks and valleys in microns that exist in the area.

As a second method, instead of relying only on the frictional resistance due to the contact pressure between the threaded surfaces of bolt c and nut d,
To increase the moment of frictional resistance generated between the tightening surfaces of the bolts c and nuts d and the seating surfaces e and f of the connecting rod body a and its cap b. In order to increase this moment of frictional resistance, when the tightening surfaces of bolts c and nuts d are brought into pressure contact with the seating surfaces e and f of connecting rod body a and its cap b, tightening of bolts c and nuts d is necessary. If we apply contact pressure in an annular shape around the maximum diameter of the surface to generate frictional resistance, the frictional resistance moment = radius from the center of the bolt or nut to the annular shape x frictional resistance, so the frictional resistance The moment value increases. Therefore, the seating surfaces e and f of the connecting rod body a and its cap b, which come into contact with the flat tightening surfaces of the bolts c and nuts d, are not flat, but circular, or alternatively, As shown in Fig. 2, the tightening surfaces of bolts c and nuts d may be approximately formed into a conical shape with a slight concavity from the maximum diameter periphery toward the center.

However, in order to make the surface roughness of the seating surfaces e and f of the connecting rod body a and its cap b as fine as possible, there are disadvantages in terms of cost and efficiency, and at the same time, the conventional In processing equipment,
It has been extremely difficult to keep the height of the peaks and valleys low in microns. Further, the same problem as above occurs when the connecting rod body a and the seating surfaces e and f of its cap b are formed into an annular or conical shape.

(b) Purpose of the Invention To make the surface roughness of the connecting rod main body and its cap's bearing surface that comes into contact with the tightening surfaces of bolts and nuts as fine as possible, and to suppress the height of the peaks and valleys in microns, at the same time. The present invention provides a finishing method that enables processing the seat surface into a conical shape.

C. Structure of the Invention A conical or conical barrel-shaped machining roller is attached to the tip surface of a machining tool rotationally driven by a machine tool via a holder, with the large diameter portion centered. Arrange multiple pieces radially so as to face each other, and
The retainer is rotatably supported relative to the machining tool so that their rotation axes are coaxial, and the machining roller is supported by the retainer so that the rotary axis is parallel to the end surface of the machining tool. By rotatably supporting the machining roller in such a way that it can revolve around and rotate on its own axis, the machining roller is supported on the tip surface of the machining tool. The surface roughness of the connecting rod's seating surface is finished with high accuracy by pressing the connecting rod into contact with the connecting rod at a predetermined pressure, rotating the processing tool in this state, and causing the processing roller to rotate and revolve on the seating surface. At the same time, the seat is machined into a conical shape with a slight depression facing toward the center of the seat.

D. Embodiment FIGS. 3 and 4 are drawings showing a processing tool consisting of a processing roller used in the present invention and a Superoll that holds the processing roller. In the figure, 1 indicates Superoll, and 2 indicates Superoll 1. A mandrel 3 integrally formed at the rear end is a processing roller that is held in a predetermined number (three in the drawing) radially on the front end surface of the Superoll 1 via a holder 4. The cage 4 is rotatably supported by the Superoll 1 so that the rotation axes of both are coaxial, as shown in FIG. 4, and the processing roller 3
As shown in FIG. 3, is rotatably supported by the cage 4 so that the rotation axis is parallel to the end surface of the Superoll 1, that is, perpendicular to the rotation axis of the cage 4. ing. Therefore, when Superoll 1 is rotated, processing roller 3 revolves while rotating on its own axis at the tip of Superoll 1. The outer shape of the processing roller 3 is a conical shape with a larger diameter on the inner peripheral side of the Superoll 1 in order to finish the seating surfaces e and f of the connecting rod body a and its cap b into a conical shape. Alternatively, it is shaped like a cone, and its tapered surface is shaped like an arc to form a bulge in the shape of a barrel.

Fig. 5 is a drawing showing a holder 5 used when the above-mentioned processing tool is attached to the headstock of a machine tool. 8 is an adapter for vertical dimension adjustment that is slidably inserted in the vertical direction, and 9 is an adapter 7 for vertical dimension adjustment.
It is a locking nut screwed onto the threaded part 7a at the tip,
The seat surface of the locking nut 9 is brought into contact with the tip end surface of the main shaft 6, and pressed against the vertical dimension adjustment adapter 7 at the tip of the push screw 10 threaded onto the side of the main shaft 6, thereby creating an adapter for vertical dimension adjustment. 7. Perform positioning. Reference numeral 11 is a tool holder into which the mandrel 2 of the Superoll 1 described above is inserted into the tip, and whose rear end is inserted into the vertical dimension adjustment adapter 7 via a rotation stopper key 12; 13 is screwed into the rear end of the tool holder 11. The stopper bolt 14 is a stopper screwed onto a portion of the end of the stopper bolt 13 that protrudes from the rear end of the vertical dimension adjustment adapter 7. Reference numeral 15 denotes a disc spring for adjusting the pressing force that is press-fitted between the rear end of the tool holder 11 and the adapter 7 for vertical dimension adjustment. It is designed to apply pressure. Further, the pressing force is adjusted by adjusting the number of disc springs 15.

In the above configuration, when finishing the seating surfaces e and f of the connecting rod body a or the cap b using the processing roller 3 according to the present invention, the processing roller 3 is held. Superoll 1
Attach the holder 5 with the holder 5 attached to the tip to the headstock of the machine tool. In this state, the processing roller 3 is pressed against the seating surfaces e and f of the connecting rod body a or the cap b with a predetermined pressure, and then the Superoll 1 holding the processing roller 3 is rotated by the holder 5. Rotate by rotating. Then, the processing roller 3, which is held between the tip surface of the Superoll 1 and the seating surfaces e and f of the connecting rod body a or the cap b, is moved by the retainer 4 due to the rotational movement of the Superoll 1. While being held, it revolves on the seat surface e or f and rotates on its axis. At this time, as the processing roller 3 moves, the locus of the operating point P of the processing roller 3 spirals toward the center or outer diameter of the seat surface e or f, as shown by the two-dot chain line in FIG. At the same time, the processing roller 3 performs an oscillating motion around the operating point P, and performs a sliding motion instead of a rolling motion outside the operating point P.

In this way, the conical or conical and barrel-shaped processing roller 3 is pressed against the seating surfaces e and f of the connecting rod body a or the cap b with a predetermined pressure. If it rotates on f and at the same time slips during rotation, the surface roughness of the seating surfaces e and f of the connecting rod body a and its cap b will be fine, and the height of the peaks and valleys in microns will be fine. can be lowered, and at the same time, the seating surfaces e and f can be processed into conical shapes.

E. Effects of the Invention As described above, a conical or conical and barrel-shaped processing roller is pressed against the connecting rod main body and the seating surface of its cap at a predetermined pressure, and in this state, the processing roller is If the rollers are rotated on the bearing surface and simultaneously revolved, and the processing roller is rotated on the bearing surface and slips during rotation, the surface roughness of the connecting rod body and its cap seating surface can be reduced. It is now possible to finish the seat surface to a fine degree, reducing the height of the micron-level peaks and valleys that occur on the seat surface, and at the same time making it possible to process the seat surface into a conical shape. Therefore, if the seating surface of the connecting rod body and its cap are finished using the above processing method, when the connecting rod body and its cap are fastened using bolts and nuts, the bolts and nuts will be tightened easily. It is possible to increase the moment of frictional resistance generated between the connecting rod body and the seating surface of its cap, and at the same time, it can reduce the "strike action".
As a result, the peaks of the peaks and valleys formed on the seat surface are crushed and the contact pressure generated on the tightening surfaces of the bolts and nuts can be prevented from disappearing, thereby preventing the bolts and nuts from loosening.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the shape of the connecting rod main body and its cap, Fig. 2 is a sectional view showing the shape of the connecting rod main body or the seat surface of the cap, and Fig. 3 is a processing used in the present invention. Fig. 4 is a front view of the processing tool, Fig. 5 is a partial sectional view showing the holder for setting the processing tool on the machine tool, and Fig. 6 is the connecting rod body or cap of the processing roller. FIG. A... Connecting rod, a... Connecting rod body, b... Cap, c... Bolt, d... Nut, e, f... Seating surface, A... Processing tool, 1... Superoll, 3...Roller for processing.

Claims (1)

[Claims] 1. A conical or conical barrel-shaped processing roller is attached to the tip surface of a processing tool rotationally driven by a machine tool via a holder, with the large diameter portion facing the center. A plurality of retainers are arranged radially in a radial manner, and the retainer is rotatably supported relative to the machining tool so that both axes of rotation are coaxial. By rotatably supporting the processing roller so that it is parallel to the end surface of the processing tool, the processing roller is held on the tip surface of the processing tool so as to be able to revolve and rotate, and this processing roller is connected to the connecting groove. The seat of the connecting rod is pressed against the bolt or nut of the connecting rod with a predetermined pressure, the processing tool is rotated in this state, and the processing roller is rotated and revolved on the seat surface. A method for processing a connecting rod seat surface, which is characterized in that the surface roughness of the surface is finished with high precision, and at the same time, the seat surface is processed into a conical shape with a slight concave toward the center.