JP2011163499A - Assembling crankshaft for automotive engine and assembling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an assembling crankshaft for automotive engine, configured so that processing for supplying lubricating oil to a bearing to be assembled to a journal and a pin can be extremely simplified, and the assembling and combining thereof by shrink fitting can be easily performed with high reliability. <P>SOLUTION: The journal 2 and the pin 3 respectively having connecting shafts 2b, 3b extended to shaft ends thereof, and an arm 10 having fitting shaft holes 15, 16 to which the connecting shafts 2b, 3b are fitted and a balance weight 11 formed as an integrated unit thereto are manufactured respectively as single bodies, and combined and assembled together by shrink fitting. Each of the journal 2 and the pin 3 has a hollowed shaft shape opened at both ends, and includes a vertical hole 2c, 3c allowing a hollow portion 2e, 3e to communicate with the outer periphery and an oil basin 2d, 3d formed on the outer periphery so as to communicate therewith. The connecting shafts 2b, 3b are tapered at 0.5-10°, and the connecting shaft 2b of the journal 2 has a pyramidal shape. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an assembly-type crankshaft for an automobile engine, and more particularly to a crankshaft that is lightweight and easy to process an oil passage for lubrication and is easy and reliable to assemble.

A crankshaft for an automobile engine is composed of a journal supported by a bearing of a cylinder block, a pin connected to a connecting rod of a piston, and an arm connecting the journal and the pin, and a balance weight is integrally provided on the arm. It has been.
The crankshaft is usually made of a forging die in which a journal, a pin, and an arm are integrated. However, the manufacturing cost is increased and the weight is increased, which makes the crankshaft expensive.

Therefore, the applicant has previously developed a lightweight and inexpensive crankshaft in which the journal, pin, and arm are separately manufactured, and the journal and pin are joined to the arm by shrink fitting. (Patent Document 1).
In this crankshaft, tapered connecting shafts are respectively extended at the shaft ends of the journal and the pin, and the shaft is provided with a fitting shaft hole formed in a conical surface into which the connecting shaft is fitted.

By the way, the journal and the pin are provided with bearings (slide bearings), and in order to supply lubricating oil to the journals and pins, the lubricating oil is pumped to the journal by an oil pump to lubricate the journal bearings and part of them. It is fed to the outer periphery of the pin.
This oil passage is generally drilled obliquely from a journal to a pin with a drill (for example, see Patent Document 2).

Utility Model Registration No. 3129273 JP 2006-200681 A

The crankshaft disclosed in Patent Document 1 has not only been mass-produced with high quality but also significantly reduced weight by making the journal and the pin into a hollow shaft shape and accurately making the arm by die forging. However, for the formation of the oil passage for lubrication to the bearing, since the journal and the pin are hollow shaft-shaped, after assembly, a configuration is adopted in which the tube is inserted by obliquely drilling the outer periphery of the pin, etc. There is a problem that the processing becomes complicated, and since this oil passage perforates the shrink-fitting portion, there is a concern that there is a possibility that the fixing due to the shrink-fitting may be impaired.
Further, the journal and the pin are joined to the arm by shrink fitting, but since they are tapered, there is a problem that skill is required to make the axial direction and the rotational direction be in the correct positions.

  Accordingly, the present invention provides an assembly for an automobile engine in which processing for supplying lubricating oil to a bearing assembled to a journal and a pin is extremely simple, and assembly by shrink fitting is simple and reliable. It is an object of the present invention to provide a crankshaft and an assembling method thereof.

  The assembly type crankshaft for an automobile engine of the present invention employs the following means in order to achieve the above object. That is, a journal and a pin with a connecting shaft extending at the shaft end, and an arm with a fitting shaft hole that fits with the connecting shaft and an integrally formed balance weight are manufactured individually. In the assembly type crankshaft for an automobile engine assembled by combining the connecting shaft with the fitting shaft hole by shrink fitting, the journal and the pin are hollow shafts having both ends open and hollow. A vertical hole communicating from the portion to the outer periphery is formed and an oil sump communicating with the vertical hole is formed on the outer periphery. The connecting shaft has a taper of 0.5 to 10 degrees, and the connecting shaft of the journal is a pyramid. It is characterized by being.

  The present invention relates to an improvement of a built-in crankshaft for an automobile engine that is manufactured by separately manufacturing journals, pins, and arms, and fixing them by shrink fitting, and in particular, lubrication of slide bearings attached to the journals and pins. The oil supply path is simplified, and assembly (shrink fitting) is performed with high reliability and simplicity.

  Processing of the oil passage for supplying lubricating oil to the slide bearing is performed by drilling the central part of the journal and the pin so that both ends are open and forming a vertical hole communicating from the hollow part to the outer periphery. At the same time, the oil sump communicating with the vertical hole is only cut on the outer periphery. Of course, this processing is performed before shrink fitting.

The journal and pin may be cut from a round bar. The central part is penetrated and pipe-shaped and both ends are left open. A steel pipe may be used if an appropriate size is available.
The connecting shaft is formed into a tapered cone or pyramid that gradually decreases outward, and the connecting shaft of the journal is a pyramid. Of course, the connecting shaft of the pin may be a pyramid. Here, the pyramid does not mean a geometrically accurate one, but includes, for example, a shape obtained by cutting a part of a conical surface flat.

The reason why the connecting shaft of the journal is a pyramid is to make assembly easy and reliable.
That is, the pin is arranged by being rotated by a predetermined angle in a plane perpendicular to the central axis of the crankshaft, but the angle varies depending on the type of engine and the number of cylinders. By forming the connecting shaft of the journal into a pyramid and rotating the shaft hole for fitting the arm by a predetermined angle, the connecting shaft is fitted, so that the positioning can be performed easily and reliably.

  The taper angle of the connecting shaft is 0.5 to 10 degrees. If it is 0.5 degrees or less, there is a concern that a gap may be formed between the fitting shaft hole, and if it is 10 degrees or more, there is a concern that a deviation may occur due to vibration accompanying high-speed rotation.

A plurality of vertical holes for lubrication may be provided. Further, the oil reservoir formed on the outer peripheral surfaces of the journal and the pin is for spreading the lubricating oil over the entire bearing surface, and may be appropriate, for example, by providing a recess around the vertical hole portion.
Desirably, as described in claim 2, a longitudinal hole of the journal and the pin is drilled in a central portion in the axial direction, and a spiral groove communicated with the longitudinal hole is formed on the outer periphery of the journal and the pin. Good.
Lubricating oil is supplied to the journals and pin bearings of the crankshaft by injecting lubricating oil from the oil pan through a filter into the hollow portions of the journals and pins. Since the pin rotates around the journal, it is arranged at an appropriate position on the track, and the lubricating oil is jetted in time.

  The arm is integrally formed with a balance weight, and is preferably made of iron or aluminum alloy, and is subjected to imprinting immediately after hot forging and trimming. According to this, since a thing with high dimensional accuracy is made, cutting by a machine tool can be reduced as much as possible. A conical or pyramid fitting shaft hole in which the journal and pin are shrink-fitted is processed with high accuracy.

  According to the third aspect of the present invention, the assembly of the journal and the pin to the arm can be made simpler, and it is configured as follows. That is, in assembling (shrink fitting), when the arm is made of iron, it is heated to 200 to 600 degrees C. When the arm is made of aluminum alloy, it is heated to 100 to 400 degrees C, and a plate-like gauge having the same taper angle is heated. After fitting into the inserted shaft hole and confirming that the diameter is a predetermined size, a connecting shaft of a normal temperature journal and pin is inserted into the shaft shaft for insertion to cool the arm. It is characterized by combining.

  When the arm is made of iron, it cannot be larger than the outer dimensions of the journal and pin at 200 ° C. or less. In addition, at 600 degrees C or higher, the organization changes. On the other hand, in the case of an aluminum alloy, the required size cannot be obtained at 100 ° C. or less. Further, at 400 ° C. or higher, the structure changes, which is not desirable.

The assembly-type crankshaft for an automobile engine according to the present invention has a journal and a pin in the form of a hollow shaft open at both ends, and a vertical hole communicating from the hollow portion to the outer periphery is formed and the outer periphery communicates with the vertical hole. Since the oil reservoir is formed, the oil passage for the lubricating oil can be formed very easily at the stage of the single product before assembly, and the troublesome processing of drilling the oblique oil passage in the assembled crankshaft as in the past is required. Disappear. In addition, since the shrink-fitting portion is not machined, the reliability of the shrink-fitting is not impaired. Further, since both ends of the hollow portion of the journal and the pin are open, not only does it contribute to weight reduction, but it is also possible to prevent the lubricating oil from staying and deteriorating and collecting foreign matter.
In addition, since the connecting shaft has a taper of 0.5 to 10 degrees and the connecting shaft of the journal is a pyramid, the arm can be assembled at a predetermined angle with high accuracy and simply. Moreover, the assembled product has no slip in the rotational direction.

  The invention according to claim 2 is characterized in that an oil sump on the outer periphery of the journal and the pin is formed in a spiral groove having a vertical hole formed in the central portion in the axial direction and communicating with the vertical hole on the outer periphery of the journal and the pin. Therefore, the lubricating oil can be reliably supplied to the entire bearing surface with a simple process.

  According to a third aspect of the present invention, when the arm is made of iron, it is heated to 200 to 600 degrees C. When the arm is made of aluminum alloy, it is heated to 100 to 400 degrees C, and a plate-like gauge having the same taper angle is heated. After fitting into the fitting shaft hole and confirming that the diameter is a predetermined size, the connecting shaft of the normal temperature journal and pin is inserted into the fitting shaft hole, and the arm is cooled. Since the crankshaft is assembled by merging, the assembly work can be easily performed, and even if it is not an expert, it will not fail.

1 is a perspective view of a model for a four-cylinder engine, showing an embodiment of a crankshaft for an automobile engine of the present invention. FIG. 2 is an enlarged view showing details of the part (arms 10C, 10D) of FIG. FIG. 3 is a plan view, a front view, and a side view showing the journals 2K, 2L, and 2M. It is the front view and side view which show pins 3J, 3K, 3L, and 3M. It is a side view of the arm 10D. FIG. 3 is an AA view of FIG. 2. It is a front view which shows the plate-shaped gauge for confirming whether the dimension at the time of the heating of the shaft hole for arm fitting is appropriate.

Hereinafter, embodiments of the crankshaft of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a schematic configuration of a crankshaft for a four-cylinder engine according to the present invention, and FIG. 2 is an enlarged view of the vicinity of the arms 10C and 10D which are a part thereof.
3 to 6 show details of the constituent members. FIGS. 3 and 4 are a front view and a side view of the journal and the pin, and FIGS. 5 and 6 are a side view and a front view of the arm.

As shown in FIG. 1, the crankshaft 1 connects five journals 2J to 2N, which are rotatably supported by a cylinder block (not shown) via bearings, and a connecting rod 5 via the bearings. Four pins 3J to 3M are integrally connected to the eight arms 10A to 10H.
As shown in FIG. 2, this connection is assembled by arranging journals 2 </ b> K and 2 </ b> L and a pin 3 </ b> K with arms 10 </ b> C and 10 </ b> D integrated with a balance weight 11 in a stepwise manner. In assembly, ring-shaped bearings are preliminarily fitted onto the journals 2J to 2N and pins 3J to 3M.

Next, each component will be described.
As shown in FIG. 3, the journals 2K, 2L, and 2M have a hollow shaft shape having a hollow portion 2e, and both ends thereof are open. Further, pyramid-shaped connecting shafts 2b that are gradually inclined outward are integrally formed at both ends of the journal portion 2a. Further, a vertical hole 2c is formed in the central portion of the journal portion 2a in the axial direction so as to communicate with the hollow portion 2e and penetrate to the shaft surface, and communicates with the vertical hole 2c as an oil reservoir on the outer periphery of the journal portion 2a. A spiral groove 2d is formed. In this groove 2d, the upper groove 2d and the lower groove 2d in FIG. 3 are formed in a spiral shape opposite to each other, and function so that the lubricating oil spreads over the entire surface of the slide bearing.

As shown in FIG. 4, the pin 3 </ b> L is hollow and open at both ends, and has conical connecting shafts 3 b that gradually incline outward at both ends of the pin portion 3 a. Further, a vertical hole 3c is formed in the axial center portion of the pin portion 3a so as to communicate with the hollow portion 3e and penetrate to the shaft surface, and communicates with the vertical hole 3c as an oil reservoir on the outer periphery of the pin portion 3a. A spiral groove 3d is formed.
This groove 3d is the same as the groove 2d formed in the journal 2a of FIG.
Here, the vertical holes 2c and 3c formed in the journals 2K to 2M and the pins 3J to 3M have a diameter of 3 to 5 mm, and the grooves 2d and 3d have a width of 3 mm and a depth of 1.5 mm.

As shown in FIGS. 5 and 6, the arm 10D has a balance weight 11 formed integrally, a pyramid-shaped fitting shaft hole 15 into which the connecting shaft 2b of the journal 2L is fitted, and a connecting shaft 3b of the pin 3K. A conical insertion shaft hole 16 is provided in which the is fitted.
Here, the overall size is a size that fits in a circle of R (about 150 mm) centered on the axis of the journal 2L, and the thickness is about 16 mm.
When the connecting shaft 3b of the pin 3K is positioned directly below the center of the pyramid-shaped fitting shaft hole 15 to which the journal 2L is fixed (axial center of the journal 2L), the balance weight 11 is positioned at the top. The shape is almost like the face of a woman with Japanese hair.

  The balance weight 11 is formed in a fan shape of approximately 150 degrees, and the fan-like base end is on the horizontal center line of the journal 2L. The fan-shaped outer edge portion is formed to have a cross section of approximately 16 mm square, and the inner side (near the journal 2 </ b> L) is formed as a 5 mm thin wall that is recessed on both the front and back sides to form a recess 12.

The lower part of the arm 10D has a shape in which a circular arc having a radius of about 30 mm and a base end of the fan-shaped balance weight 11 are connected with a curve from the center of the pin 3K, and the lower end portion is about 150 mm of the circular arc of the outer edge portion of the balance weight 11. Inscribed in a circle.
Boss portions 13 and 14 having a thickness of about 3.5 mm are formed on the surface on which the journal 2L and the pin 3K are fixed.

  The arm 10D is made by performing a coining process in which the arm 10D is immediately placed in a closed mold and pressed after hot forging and then trimmed. According to this, the concavo-convex shape of the mold forming surface can be efficiently and accurately transferred, so that a high dimensional accuracy can be achieved. Thereafter, the fitting shaft holes 15 and 16 are machined.

As for the assembly of the crankshaft, the journal 2L and the pin 3K are obtained by inserting a ring-shaped bearing (not shown) from the shaft end and then burning it into the fitting shaft holes 15 and 16 of the arm 10D, respectively. Merge together.
In shrink fitting, the journal 2L and the connecting shafts 2b and 3b of the pin 3K are accurately attached in a short time to the front (here, the side where the journal is attached) and the back (the side where the connecting rod is attached) of the arm 10D. It is necessary.

First, the arm 10D is heated to 200 to 600 degrees C at high frequency to expand the fitting shaft holes 15 and 16 to a predetermined size.
Next, it is confirmed whether the fitting shaft holes 15 and 16 have a predetermined size (preset with dimensions that allow the connecting shafts 2b and 3b to be inserted to a predetermined position).
This operation is easily performed using the gauge 20 shown in FIG.

  There are two types of gauges 20 for the fitting shaft hole 15 and the fitting shaft hole 16, and each of the gauges 20 is provided with a tapered portion 23 at the same angle as the taper of the fitting shaft holes 15 and 16. The contact surface 21 is formed at the base of the taper. The length between the root portions of the taper portion 23 is set to a reference value when the arm fitting shaft holes 15 and 16 are heated to expand to a predetermined size.

The work is performed by inserting the front side into the fitting shaft holes 15 and 16 of the arm 10D heated with the handle 22 of the gauge 20 so that the upper ends of the fitting shaft holes 15 and 16 are in contact with the contact surface 21. To see if it touches. If contact is made, it is confirmed that the fitting shaft holes 15 and 16 have reached the reference value.
When it is confirmed that the fitting shaft holes 15 and 16 have a size exceeding the reference value, the connecting shafts 2b and 3b of the journal 2L and the pin 3K are inserted into the fitting shaft holes 15 and 16. Then, the arm 10D is rapidly cooled.
As a result, the journal 2L and the pin 3K can be assembled and assembled to the arm 10D almost simultaneously.

  In the above description of the embodiment, the arm is shown with specific dimensions so that the contents of the invention can be understood well. However, it goes without saying that the present invention is not limited to this dimension. Absent.

1 crankshaft 2a journal portion 2b connecting shaft 2c vertical hole 2d groove 2e hollow portion 2J, 2K, 2L, 2M, 2N journal 3a pin portion 3b connecting shaft 3d groove 3e hollow portion 3J, 3K, 3L, 3M pin 5 connecting rod
10A, 10B, 10C, 10D Arm 10E, 10F, 10G, 10H Arm 11 Balance weight 12 Concave portion 13, 14 Boss portion 15 Pyramid hole 16 Conical hole 20 Gauge 21 Contact surface 22 Handle 23 Tapered portion

Claims (3)

  A journal and a pin having a connecting shaft extending at the shaft end, and an arm having a fitting shaft hole that fits with the connecting shaft and an integrally formed balance weight, are manufactured individually. In an assembling type crankshaft for an automobile engine assembled by combining the connecting shaft into the fitting shaft hole by shrink fitting, the journal and the pin have a hollow shaft shape whose both ends are open, and from the hollow portion A vertical hole communicating with the outer periphery is formed and an oil sump communicating with the vertical hole is formed on the outer periphery. The connecting shaft has a taper of 0.5 to 10 degrees, and the connecting shaft of the journal is a pyramid. An assembly type crankshaft for an automobile engine.   2. The assembly type crank for an automobile engine according to claim 1, wherein the oil sump on the outer periphery of the journal and the pin is formed with a spiral groove communicating with the vertical hole formed in a central portion in the axial direction. shaft.   In the assembly, when the arm is made of iron, it is heated to 200 to 600 degrees C. When the arm is made of aluminum alloy, it is heated to 100 to 400 degrees C, and a plate-like gauge having the same taper angle is heated. After fitting into the hole and confirming that the diameter is a predetermined size, the connecting shaft of the normal temperature journal and pin is inserted into the fitting shaft hole, and the arm is cooled and united. The assembly method of the assembly-type crankshaft for motor vehicle engines of Claim 1 or Claim 2.

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