JP2017187088A - Method for manufacturing connecting rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a connecting rod in which any profile processing including a tapered part and an oil groove can be carried out on an inner peripheral surface of a small end hole of the connecting rod while suppressing occurrence of a step.SOLUTION: A method for manufacturing a connecting rod having a tapered part and an oil groove on an inner peripheral surface of a small end hole includes a cutting step of cutting the inner peripheral surface of the small end hole in a single step by moving a cutting tool 60 along a central axis of the small end hole. In the cutting step, the tapered part and the oil groove are formed on the inner peripheral surface of the small end hole by inclining a rotation axis A of the cutting tool 60 with respect to the central axis of the small end hole by a hydraulic power inclination unit 20.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a connecting rod including a cutting process.

  2. Description of the Related Art Conventionally, an invention related to a machining method when machining a connecting rod (hereinafter abbreviated as a connecting rod) of an engine has been known (see Patent Document 1 below). The connecting rod is a member that connects the crankshaft and the piston and converts the reciprocating motion of the piston into the rotational motion of the crankshaft.

  The connecting rod has a large end connected to the crankshaft and a small end connected to the piston pin. The small end portion has a small end hole (small diameter hole) through which the piston pin is inserted, and is connected to the piston by the piston pin.

  In the connecting rod processing method described in Patent Document 1, first, a processing reference hole and a processing reference surface are formed by provisionally processing the small diameter hole and the side surface of the connecting rod. Next, the post-process is advanced using the processing reference hole and the processing reference surface to form large / small diameter holes satisfying a desired positional tolerance and large / small end portions having different widths.

  In the connecting rod processing method described in Patent Document 1, the chamfered shape of the small-diameter hole is formed in a step before finishing the small-diameter hole, and the small end portion is cut into a predetermined width in the final step. It is characterized by that. Thereby, the burr | flash produced at the time of formation of the chamfering shape of a small diameter hole can be removed in the finishing process of a small diameter hole. In addition, by performing the process of cutting the small end to a predetermined width in the final process, the same flatness of the side surfaces of the large and small ends of the connecting rod is maintained until the process one step before the final process. Can be used as

JP-A-9-133123

  Although the processing method described in Patent Document 1 can form a tapered portion in the vicinity of the opening of the small end hole of the connecting rod, it is difficult to form an oil groove on the inner peripheral surface of the small end hole. Using a multi-axis machining center, it is possible to form a tapered portion near the opening of the small end hole of the connecting rod and form an oil groove on the inner peripheral surface of the small end hole through a plurality of processing steps. However, there is a possibility that an unacceptable level difference may occur on the inner peripheral surface of the small end hole of the connecting rod through a plurality of processing steps.

  This invention is made | formed in view of the said subject, The arbitrary profile process containing a taper part and an oil groove can be performed on the inner peripheral surface of the small end hole of a connecting rod, suppressing generation | occurrence | production of a level | step difference. It aims at providing the manufacturing method of the connecting rod containing a cutting process.

  In order to achieve the above object, a manufacturing method of a connecting rod according to the present invention is a manufacturing method of a connecting rod having a tapered portion and an oil groove on an inner peripheral surface of a small end hole, and a cutting tool is placed at the center of the small end hole. A cutting step of cutting the inner peripheral surface of the small end hole in one step by moving along an axis, and in the cutting step, the rotation axis of the cutting tool is centered on the small end hole by a hydraulic tilt unit. The tapered portion and the oil groove are formed on the inner peripheral surface of the small end hole so as to be inclined with respect to the shaft.

  A connecting rod manufactured by a method for manufacturing a connecting rod (hereinafter abbreviated as connecting rod) of the present invention generally has a large end connected to a crankshaft and a small end connected to a piston pin. ing. The small end portion has a small end hole through which the piston pin is inserted. The small end of the connecting rod is connected to the piston by a piston pin.

  The connecting rod manufacturing method of the present invention includes, for example, a casting process, a forging process, a cutting process, a grinding process, and the like, but a known process can be adopted for processes other than the cutting process. The cutting process included in the manufacturing method of the connecting rod of the present invention can be performed using, for example, a connecting rod processing machine that processes the inner peripheral surface of the small end hole of the connecting rod with a cutting tool. The connecting rod processing machine can include, for example, a spindle head, a hydraulic tilt unit, a moving mechanism, and a control unit.

  The spindle head includes, for example, a spindle that is rotated by a driving device such as a motor, and the spindle is coupled to a base end portion of a tool holder, for example. A cutting tool is held at the tip of the tool holder. The spindle head rotates the tool holder by rotating the spindle, and rotates the cutting tool with the central axis of the tool holder as the rotation axis.

  The hydraulic tilting unit tilts the rotation axis of the cutting tool at an arbitrary angle with respect to the central axis of the small end hole of the connecting rod by the action of hydraulic pressure. More specifically, the spindle head includes a spindle head case that houses and holds a bearing that rotatably supports the spindle, for example. Further, the hydraulic tilting unit can have a hydraulic mechanism that tilts the head case at an arbitrary angle, for example.

  The hydraulic mechanism includes, for example, a plurality of hydraulic cylinders, and the shaft head case is inclined at an arbitrary angle by expansion and contraction of pistons of the plurality of hydraulic cylinders. As a result, the hydraulic tilting unit tilts the main spindle of the spindle head and the tool holder connected to the main spindle at an arbitrary angle by the action of hydraulic pressure, and the rotation axis of the cutting tool with respect to the central axis of the small end hole of the connecting rod It can be tilted at any angle.

  The moving mechanism is a mechanism that relatively moves, for example, the spindle head and the connecting rod in the axial direction of the small end hole of the connecting rod. More specifically, as the moving mechanism, a tool moving mechanism that moves the spindle head along the axial direction of the small end hole of the connecting rod or a workpiece moving mechanism that moves the connecting rod along the axial direction of the small end hole is used. be able to.

  The control unit includes, for example, an arithmetic unit configured by a CPU, a storage unit configured by a memory, a hard disk, and the like, a control program stored in the storage unit, an input / output unit that inputs and outputs signals, and the like. Can do. For example, the shape of the tapered portion and the oil groove formed in advance on the inner peripheral surface of the small end hole of the connecting rod can be stored in the storage portion.

  The calculation unit, for example, according to the control program stored in the storage unit, the rotation angle of the cutting tool for forming the shape of the inner peripheral surface of the small end hole, the inclination angle of the rotation axis, and the central axis direction of the small end hole The position of the cutting tool at is calculated. In addition, the calculation unit generates a control signal based on the calculation results for the motor for rotating the spindle of the spindle head, the hydraulic mechanism of the hydraulic tilt unit, and the moving mechanism in accordance with the control program stored in the storage unit.

  The input / output unit is connected to a motor that rotates the spindle of the spindle head, a hydraulic mechanism of the hydraulic tilt unit, and a moving mechanism, and outputs control signals generated by the calculation unit to these. The input / output unit receives the rotation angle signal of the cutting tool from the motor, the inclination angle signal of the rotation axis of the cutting tool from the hydraulic inclination unit, and the axial direction of the small end hole of the cutting tool from the moving mechanism. A position signal is input. The control unit causes the storage unit to store information corresponding to each signal input via the input / output unit.

  A control part implements the manufacturing method of the connecting rod of this invention according to the control program memorize | stored in the memory | storage part, for example. More specifically, a control part outputs the control signal based on the shape formed in the internal peripheral surface of the small end hole of a connecting rod to a spindle head, a hydraulic inclination unit, and a moving mechanism. As a result, the spindle head rotates the cutting tool held by the tool holder by rotating the spindle with the central axis of the tool holder as the rotation axis under the control of the control unit. The moving mechanism moves the cutting tool along the central axis of the small end hole of the connecting rod under the control of the control unit.

  Thereby, the connecting rod processing machine which performs the cutting process which concerns on the manufacturing method of this invention can implement the cutting process which cuts the internal peripheral surface of the small end hole of a connecting rod in one process. In the cutting process, the hydraulic tilting unit tilts the rotation axis of the cutting tool with respect to the central axis of the small end hole of the connecting rod, and forms a tapered portion and an oil groove on the inner peripheral surface of the small end hole.

  More specifically, the hydraulic tilt unit expands and contracts, for example, a piston of a hydraulic cylinder of a hydraulic mechanism under the control of the control unit. That is, the control unit, based on the shape of the tapered portion and the oil groove stored in the storage unit in advance, according to the position of the small end hole of the cutting tool in the central axis direction, the rotation angle of the cutting tool and the inclination of the rotation shaft The spindle head, the hydraulic tilt unit, and the moving mechanism are controlled so as to change the angle in synchronization. Thereby, the connecting rod processing machine can implement the cutting process included in the connecting rod manufacturing method of this invention, and can form the taper part and oil groove of arbitrary shapes in the internal peripheral surface of the small end hole of a connecting rod.

  As can be understood from the above description, according to the connecting rod manufacturing method of the present invention, in the cutting process, the inclination angle of the rotation axis of the cutting tool is smoothly changed by the hydraulic inclination unit, and a taper portion or the like is formed on the inner peripheral surface of the connecting rod. The oil groove can be formed in one step. Therefore, arbitrary profile processing including a taper part and an oil groove can be performed on the inner peripheral surface of the small end hole of the connecting rod while suppressing generation of a step.

The front view which shows an example of a connecting rod. The expanded sectional view which follows the central axis of the small end hole of the connecting rod shown in FIG. The block diagram which shows an example of a structure of the processing machine used for the manufacturing method of the connecting rod which concerns on one Embodiment of this invention. The conceptual diagram explaining the hydraulic inclination unit shown in FIG.

  Hereinafter, an embodiment of a manufacturing method of a connecting rod (hereinafter abbreviated as a connecting rod) of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view showing an example of a connecting rod 1 manufactured by the manufacturing method of the present embodiment. The connecting rod 1 has a large end 2 connected to the crankshaft and a small end 3 connected to the piston. The large end portion 2 has a large end hole 2a through which the crankshaft is inserted. A bearing 2b is provided on the inner peripheral surface of the large end hole 2a. The bearing 2b holds the crankshaft rotatably. The small end portion 3 has a small end hole 3a through which the piston pin is inserted.

  FIG. 2 is an enlarged cross-sectional view along the central axis C1 of the small end hole 3a of the small end portion 3 shown in FIG. The inner peripheral surface 3b of the small end hole 3a is provided with a smoothly continuous curved surface from the one end to the other end in the direction of the central axis C1 of the small end hole 3a. Specifically, the step on the inner peripheral surface 3b of the small end hole 3a is suppressed to 0.006 mm or less, for example.

  On the inner peripheral surface 3b of the small end hole 3a, taper portions 3c that expand toward the outside of the small end hole 3a are formed at both ends in the direction of the central axis C1 over the entire circumference of the small end hole 3a. Has been. On the inner peripheral surface 3b of the small end hole 3a, a concave oil groove 3e is formed on the top surface 3d between the tapered portions 3c at both ends in the direction of the central axis C1 over the entire circumference of the inner peripheral surface 3b. Has been. In addition, you may provide the oil groove 3e partially in the predetermined angle range instead of the perimeter of the circumferential direction of the internal peripheral surface 3b.

  The inclination angle of the inclined surface of the taper portion 3c is the same in the circumferential direction of the inner peripheral surface 3b. Further, the taper portion 3c has a unit length in the circumferential direction so that the piston pin and the connecting rod 1 are not seized even if both ends of the piston pin are curved and contact the inclined surface during normal combustion of the internal combustion engine. The hit area is set in advance by experiments or the like.

  In the predetermined region R of the inner peripheral surface 3b of the small end hole 3a, the length of the top surface 3d in the direction of the central axis C1 of the small end hole 3a is longer than the length of the top surface 3d at other parts of the inner peripheral surface 3b. It has been shortened. Thereby, the length in the inclination direction of the inclined surface of the taper portion 3c in the region R is made longer than the length in the inclination direction of the inclined surface of the taper portion 3c in the other part of the inner peripheral surface 3b.

  Next, an example of the connecting rod processing machine used for the cutting process included in the manufacturing method of the connecting rod 1 of this embodiment is demonstrated.

  FIG. 3 is a block diagram illustrating an example of the configuration of the connecting rod processing machine 100. The connecting rod processing machine 100 includes, for example, a spindle head 10, a hydraulic tilt unit 20, a moving mechanism 30, and a control unit 40.

  The spindle head 10 includes, for example, a spindle that is rotated by a driving device such as a motor (not shown), and the spindle is coupled to, for example, a base end portion of a tool holder 50 shown in FIG. A cutting tool 60 is held at the tip of the tool holder 50. The spindle head 10 rotates the spindle to rotate the tool holder 50, and rotates the cutting tool 60 about the central axis C2 of the tool holder 50 as the rotation axis A.

  FIG. 4 is a conceptual diagram illustrating the hydraulic tilt unit 20 shown in FIG. The hydraulic tilting unit 20 tilts the rotation axis A of the cutting tool 60 at an arbitrary angle with respect to the central axis C1 of the small end hole 3a of the connecting rod 1 by the action of hydraulic pressure. Although illustration is omitted, the spindle head 10 has, for example, a spindle head case that houses and holds a bearing that rotatably supports the spindle, and the hydraulic tilt unit 20 is, for example, a hydraulic that tilts the spindle case at an arbitrary angle. Can have a mechanism.

  The moving mechanism 30 is a mechanism that relatively moves the spindle head 10 and the connecting rod 1 in the direction of the central axis C1 of the small end hole 3a of the connecting rod 1, for example. More specifically, as the moving mechanism 30, a tool moving mechanism that moves the spindle head 10 along the direction of the central axis C1 of the small end hole 3a of the connecting rod 1, or the direction of the connecting rod 1 in the direction of the central axis C1 of the small end hole 3a. It is possible to use a workpiece moving mechanism that moves along the line.

  The control unit 40 includes, for example, a calculation unit configured by a CPU, a storage unit configured by a memory, a hard disk, and the like, a control program stored in the storage unit, an input / output unit that inputs and outputs signals, and the like. be able to. For example, the shape of the tapered portion 3c and the oil groove 3e formed in advance on the inner peripheral surface 3b of the small end hole 3a of the connecting rod 1 can be stored in the storage unit of the control unit 40.

  The calculation unit of the control unit 40, for example, according to a control program stored in the storage unit, the rotation angle of the cutting tool 60 for forming the shape on the inner peripheral surface 3b of the small end hole 3a, the inclination angle of the rotation axis A, And the position of the cutting tool 60 in the central axis C1 direction of the small end hole 3a is calculated. In addition, the calculation unit of the control unit 40 performs the operation on the motor that rotates the spindle of the spindle head 10, the hydraulic mechanism of the hydraulic tilt unit 20, and the moving mechanism 30 based on the calculation result according to the control program stored in the storage unit. Generate a control signal.

  The input / output unit of the control unit 40 is connected to a motor that rotates the spindle of the spindle head 10, the hydraulic mechanism of the hydraulic tilt unit 20, and the moving mechanism 30, and outputs control signals generated by the calculation unit to these. A signal of the rotation angle of the cutting tool 60 is input from the motor of the spindle head 10 to the input / output unit of the control unit 40, and a signal of the inclination angle with respect to the central axis C1 of the rotation axis A of the cutting tool 60 is input from the hydraulic inclination unit 20. The position signal in the direction of the central axis C1 of the small end hole 3a of the cutting tool 60 is input from the moving mechanism 30. The control unit 40 causes the storage unit to store information corresponding to each signal input via the input / output unit.

  Hereinafter, the manufacturing method of the connecting rod 1 of this embodiment using the connecting rod processing machine 100 is demonstrated.

  The manufacturing method of the connecting rod 1 of this embodiment is a manufacturing method of the connecting rod 1 which has the taper part 3c and the oil groove 3e in the internal peripheral surface 3b of the small end hole 3a, as shown, for example in FIG.1 and FIG.2. Although the manufacturing method of the connecting rod 1 of this embodiment can include a casting process, a forging process, a heat treatment process, a cutting process, a grinding process, etc., for a process other than the cutting process, a known method is adopted. Therefore, the description is omitted.

  In the manufacturing method of the connecting rod 1 of the present embodiment, the cutting tool 60 shown in FIG. 4 is moved along the central axis C1 of the small end hole 3a of the connecting rod 1, and the inner peripheral surface 3b of the small end hole 3a is formed in one step. It has a cutting process for cutting.

  In the method of manufacturing the connecting rod 1 according to the present embodiment, in the cutting process, the rotation axis A of the cutting tool 60 is inclined with respect to the central axis C1 of the small end hole 3a by the hydraulic inclination unit 20, and the inner peripheral surface of the small end hole 3a. A taper portion 3c and an oil groove 3e are formed in 3b. More specifically, the cutting process included in the manufacturing method of the connecting rod 1 of this embodiment can be implemented as follows using the above-described connecting rod processing machine 100 shown in FIGS. 3 and 4, for example.

  The connecting rod processing machine 100 performs the manufacturing method of the connecting rod 1 of this embodiment according to the control program memorize | stored in the memory | storage part of the control part 40, for example. More specifically, the control unit 40 sends control signals based on the shapes of the tapered portion 3c, the top surface 3d, and the oil groove 3e formed on the inner peripheral surface 3b of the small end hole 3a of the connecting rod 1 according to the control program. Output to the head 10, the hydraulic tilt unit 20, and the moving mechanism 30.

  As a result, the spindle head 10 rotates the cutting tool 60 held by the tool holder 50 by rotating the spindle with the central axis C <b> 2 of the tool holder 50 as the rotation axis A under the control of the control unit 40. Further, the moving mechanism 30 moves the cutting tool 60 along the central axis C <b> 1 of the small end hole 3 a of the connecting rod 1 under the control of the control unit 40. Thereby, the connecting rod processing machine 100 can implement the cutting process which cuts the internal peripheral surface 3b of the small end hole 3a of the connecting rod 1 in one process.

  In the cutting process, the hydraulic tilting unit 20 tilts the rotation axis A of the cutting tool 60 with respect to the central axis C1 of the small end hole 3a of the connecting rod 1, and the tapered portion 3c and oil are formed on the inner peripheral surface 3b of the small end hole 3a. A groove 3e is formed. More specifically, the hydraulic tilt unit 20 expands and contracts, for example, a piston of a hydraulic cylinder of a hydraulic mechanism under the control of the control unit 40, so that the rotation axis A of the cutting tool 60 is connected to the small end hole 3 a of the connecting rod 1. For example, a tapered portion 3c, a top surface 3d, and an oil groove 3e as shown in FIG. 2 are formed on the inner peripheral surface 3b of the small end hole 3a.

  That is, the control unit 40 corresponds to the position of the small end hole 3a of the cutting tool 60 in the direction of the central axis C1 based on the shapes of the tapered portion 3c, the top surface 3d, and the oil groove 3e stored in advance in the storage unit. The spindle head 10, the hydraulic tilt unit 20, and the moving mechanism 30 are controlled so that the rotation angle of the cutting tool 60 and the tilt angle of the rotation axis A are changed in synchronization. By the above, the connecting rod processing machine 100 implements the manufacturing method of the connecting rod 1 which concerns on this embodiment, the taper part 3c of arbitrary shapes, the top surface 3d, and the inner peripheral surface 3b of the small end hole 3a of the connecting rod 1 and The oil groove 3e can be formed in one step.

  As described above, according to the manufacturing method of the connecting rod 1 of the present embodiment, the inclination angle of the rotation axis A of the cutting tool 60 is smoothly changed by the hydraulic inclination unit 20 in the cutting process, and the inner peripheral surface 3b of the connecting rod 1 is thus obtained. The tapered portion 3c and the oil groove 3e can be formed in one step. Therefore, arbitrary profile processing including the tapered portion 3c and the oil groove 3e can be performed on the inner peripheral surface 3b of the small end hole 3a of the connecting rod 1 while suppressing the generation of a step.

  That is, according to the manufacturing method of the connecting rod 1 of the present embodiment, the step of the inner peripheral surface 3b of the small end hole 3a is formed by forming the tapered portion 3c and the oil groove 3e in one step on the inner peripheral surface 3b of the connecting rod 1. Can be suppressed to 0.006 mm or less, for example. On the other hand, when, for example, a multi-axis machining center is used and the taper portion 3c and the oil groove 3e are formed on the inner peripheral surface of the small end hole 3a of the connecting rod 1 through a plurality of machining steps, the inner peripheral surface is formed between the steps. There is a possibility that an unacceptable level difference occurs in 3b.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

1 Connecting rod (connecting rod)
3a Small end hole 3b Inner peripheral surface 3c Tapered portion 3e Oil groove 20 Hydraulic tilt unit 60 Cutting tool C1 Center axis A Rotation axis

Claims (1)

A manufacturing method of a connecting rod having a tapered portion and an oil groove on an inner peripheral surface of a small end hole,
A cutting step of cutting the inner peripheral surface of the small end hole in one step by moving the cutting tool along the central axis of the small end hole;
In the cutting process, the taper portion and the oil groove are formed on the inner peripheral surface of the small end hole by tilting the rotation axis of the cutting tool with respect to the central axis of the small end hole by a hydraulic tilt unit. A method of manufacturing a connecting rod as a feature.

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