JPH04282011A - Manufacture of shrinkage fit type crank shaft - Google Patents

Abstract

PURPOSE:To apply shrink fit of plural crank throws to journals with less eccentricity together with high straightness and good accuracy in a manufacture of a shrinkage fit type crank shaft where the crank throws are shrinkage fit to the journal, connected and assembled. CONSTITUTION:A journal is formed in a shape of long shaft, and a plurality of crank throws 1 are shrinkage fit to this journal 2, then, excessive part alphawhich is comprised of a journal member 2 located between both arms 1b of the respective crank throws are cut and removed. As a plurality of crank throws are shrinkage fit on the same journal, the respective crank throws can be shrinkage fit with less eccentricity and good accuracy. Further, a plurality of crank throws can be shrinkage fit simultaneously, leading to extensive improvement of the productivity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semi-assembled crankshaft, and more particularly to a method of manufacturing a shrink-fit type crankshaft suitable for manufacturing large-sized crankshafts.

0002

[Prior Art] As is well known, crankshafts are classified into integral types, semi-assembled types, and assembled types, and the semi-assembled types and assembled types are further subdivided into shrink-fit types, push-fit types, spline joint types, etc. However, for large crankshafts such as those used in marine engines, semi-assembled crankshafts using shrink fitting are most commonly used.

[0003] The conventional manufacturing method of these shrink-fit type crankshafts will be explained with reference to the conceptual explanatory diagram [FIG. 5]. First, a pin (51a ) Pair of arms (51b) on both sides of
A predetermined number of crank throws (51) with
) Prepare individual journals (52) and end shafts (53) (54) machined to the desired dimensions as shown. Then, each crank throw (
51) are sequentially shrink-fitted onto the journal (52) and the end shafts (53, 54) one by one to connect and assemble them into an integral crankshaft. Note that each crank throw (51) is shrink-fitted at a different rotational direction angle so that each pin (51a) occupies a predetermined tube angle.

0004

[Problems to be Solved by the Invention] However, in the above conventional method, each crank throw is shrunk-fitted into a journal and an end shaft that are divided into individual shaft parts, and each adjacent crank throw is different from each other. Since the tube arrangement angles are asymmetrical, it is difficult to accurately align each shaft portion that is individually shrink-fitted, and there is a problem that eccentricity is likely to occur in each shaft portion due to shrink-fitting. For this reason, the amount of eccentricity of each shaft portion is accumulated by the number of cylinders, and the amount of eccentricity is large and burdens the subsequent process, resulting in an increase in the number of processing steps.
Moreover, this affects the dimensions of the material, and as a result becomes a factor that inhibits yield improvement.

Furthermore, since it is necessary to perform cooling each time each crank throw is shrink-fitted, in addition to poor thermal efficiency, the total time required for shrink-fitting is long, making it difficult to increase productivity.

The present invention has been made to solve the problems of the prior art described above, and it is possible to shrink fit each crank throw into a journal with high straightness and precision, and furthermore, it is possible to shrink a plurality of crank throws at the same time. The object of the present invention is to provide a method for manufacturing a shrink-fit type crankshaft, which can also be fitted and can improve productivity.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration. That is, the method for manufacturing a shrink-fit type crankshaft according to the present invention includes shrink-fitting a plurality of crank throws, each of which has a pair of arms on both sides of a pin and has through-holes for shrink-fitting in the arms, onto a journal. In a manufacturing method for a shrink-fit type crankshaft that connects and assembles, a journal is formed into a long shaft that connects and passes through a plurality of crank throws, a plurality of crank throws are shrink-fitted to this journal, and then each crank throw is The journal material present between the pair of arms is removed.

[0008]

[Operation] Unlike the journal which is individually divided as in the prior art, in the present invention, a plurality of crank throws are shrink-fitted into a journal formed on a long shaft passing through a plurality of crank throws. After that, the journal material existing between the pair of arms of each crank throw is removed. In other words, multiple crank throws are inserted on the same shaft and shrink-fitted, so each crank throw is accurately aligned with high straightness. Shrink fitting is possible, and furthermore, since a plurality of heated crank throws can be inserted on the same shaft and simultaneously cooled and shrunk fitted, the time required for shrink fitting can be significantly shortened.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the method for manufacturing a shrink-fit type crankshaft according to the present invention will be described below with reference to the drawings.

[0010] FIG. 1 is a conceptual explanatory diagram of one embodiment of the method of the present invention, in which (a) and (b) are explanatory diagrams of the intermediate material before shrink-fitting, and (c) is an illustration of the intermediate material before shrink-fitting. Schematic diagram explaining the process, (
d) The figure shows the state after shrink fitting.

In this example, first, a number of identical crank throw members corresponding to the number of cylinders of the crankshaft to be manufactured are manufactured, and a journal shaft member having a length corresponding to the total length of the crankshaft is manufactured. do. Here, the crank throw material is formed into one piece by a bending forging method and subjected to a prescribed heat treatment, and then has a pair of arms (1b) on both sides of a pin (1a) as shown in Figure (a). , and is processed into a crank throw (1) as an intermediate material before shrink-fitting, with journal holes (1c) for shrink-fitting provided in both arms (1b). On the other hand, the journal shaft material is formed into one piece by a normal forging method, subjected to a prescribed heat treatment, and then has a flange (2b) at one end as shown in Figure (b). A journal shaft (as an intermediate material before shrink fitting) whose part (2a) has been finished to the dimensions before polishing (
2) Process into. Note that the diameter D of the journal hole (1c) of the crank throw (1) and the diameter d of the main shaft portion (2a) of the journal shaft (2) are finished to a fitting precision that allows them to be shrink-fitted to each other.

[0012]Then, each of the crank throws (1) in the number corresponding to the number of cylinders is fitted with a predetermined spacing and piping angle using a vertical pit type shrink-fitting equipment (3), as shown in Figure (c). It is held and heated to a predetermined temperature.

[0013] Here, the shrink-fitting equipment (3) in this embodiment includes a plurality of slow holding devices (3a) equipped with heating/cooling means and movable up and down, and a plurality of slow holding devices (3a) arranged above and below the center thereof. Each crank throw (1) is heated by a heating means provided in the respective throw holding device (3a).

When each crank throw (1) is heated to a predetermined temperature, the journal shaft (2), which has been previously suspended from the upper shaft lifting device (3b) with the flange (2b) facing upward,
is lowered and its main shaft portion (2a) is inserted into the journal hole (1c) of each crank throw (1). At this time, the lower shaft lifting device (3c) is connected to the journal shaft (2).
By reaching the lower end of the journal shaft (2), descending to a predetermined height position and stopping, the axial insertion position of the journal shaft (2) is regulated.

Next, each crank throw (1) is cooled by the cooling means provided in the slow holding device (3a), and the number of crank throws (1) corresponding to the number of cylinders are simultaneously cooled on the journal shaft (2). Shrink-fit in series.

Next, this connected body is taken out of the shrink-fitting equipment (3), and as shown in FIG. The surplus portion α (indicated by the diagonal parallel dot-dash line in the figure) is cut and removed by ordinary mechanical means, and then a conventional finishing process is carried out.

In the present embodiment described above, since the number of crank throws corresponding to the number of cylinders is shrink-fitted onto the same journal shaft, the time required for the shrink-fitting can be significantly shortened, and Each crank throw can be shrink-fitted with high accuracy and high straightness, increasing processing efficiency in post-processing.

Next, an example of manufacturing a shrink-fit type crankshaft having flanges at both shaft ends will be described with reference to FIG. 2.

[0019] FIG. 2 is a conceptual explanatory diagram of another embodiment of the method of the present invention, in which (a) is an explanatory diagram of the intermediate material before shrink-fitting, and (b) is the state after shrink-fitting. FIG. The basic configuration of this example is the same as the example shown in [Figure 1].
Components equivalent to those shown in FIG. 1 are given the same reference numerals and their explanations are omitted, and only the differences will be summarized here.

In this embodiment, each crank throw (1)
As shown in Figure (a), the journal shaft (12) to be shrink-fitted is made up of a main journal shaft (13) with a length approximately corresponding to the entire length of the crankshaft to be manufactured, and a short auxiliary journal shaft (13).
13) Divide into two. In addition, these main and auxiliary journal shafts (13) and (14) have a collar (13b) at one end of the shaft.
) (14b), and each main shaft portion (1
3a) (14a) is finished to the dimensions before polishing.

Similar to the example shown in FIG. 1, each of the crank throws (1) corresponding to the number of cylinders is installed in a vertical pit type shrink-fitting facility (as shown in FIG. 1B). 3
) at a predetermined interval and piping angle and heat it.

Next, the journal shaft (12) is inserted into each crank throw (1) heated to a predetermined temperature. In this embodiment, the main journal shaft (13) is inserted into the upper shaft lifting device (3b). While hanging, the auxiliary journal shaft (
14) on the lower shaft lifting device (3c), and from both the upper and lower sides, the main shaft portions (13a) (14a) of the main and auxiliary journal shafts (13) (14) are inserted into each crank throw (
1) Insert into the journal hole. Here, the lower end of the main shaft portion (13a) of the auxiliary journal shaft (14) is inserted until it passes through the journal hole above the crank throw (1) held at the lowest position, while the auxiliary journal shaft The upper end of the main shaft portion (13a) of (14) is inserted only into the lower journal hole of the crank throw (1). In this embodiment, when inserting the main journal shaft (13), a spacer (14) with a predetermined height is placed on the upper end surface of the main shaft (13a) of the auxiliary journal shaft (14). ) and the auxiliary journal shaft (13).

Next, in the same way as in the example shown in FIG. 1, each crank throw (1) is cooled, and the number of crank throws (1) corresponding to the number of cylinders are simultaneously controlled by the main and auxiliary journal shafts (13). ) (14) After shrink-fitting on top, (c)
Both arms of each crank throw (1) (
1b) Cut and remove the surplus portion α made of the journal shaft (12) material existing in between.

[0024] In this embodiment described above, a shrink-fit type crankshaft having flanges at both shaft ends can be efficiently manufactured with the same effect as the example shown in Fig. 1. Can be done.

In the two embodiments described above, a vertical pit-type shrink-fitting equipment was used, but in the method of the present invention, a horizontal-type shrink-fitting equipment can be used. An example of manufacturing a shrink-fit type crankshaft using horizontal shrink-fit equipment will be explained with reference to FIG. 3.

[0026] [FIG. 3] is a conceptual explanatory diagram of another embodiment of the method of the present invention. In this embodiment, as shown in FIG. 3, the journal shaft (2) formed as a long shaft is cantilever-supported in the horizontal direction, and the angle indexing device (31) rotates and stops at a predetermined angle phase. ) and this angle indexing device (3
A journal shaft (2) provided on a common base (30) with 1), equipped with heating/cooling means, and supported in the horizontal direction.
A slow-retention device that can move forward and backward along the axis of
32) and at least two places on the base (30) in the middle part in the front-rear direction, and a shaft support part (33a) is provided at the upper end part.
Horizontal shrink-fitting equipment was used, which was equipped with a journal shaft support device (33) that was movable up and down, and a journal shaft support device (33) that was retractable to the side of the base (30).

In this embodiment, each crank throw (1)
is held by the slow holding device (32) and fitted into the journal shaft (2) sequentially from the horizontal direction, and is shrink-fitted at a predetermined axial position. In addition, when each crank throw (1) is inserted, the journal shaft support device (33) alternately moves up and down and advances and retreats to horizontally hold the journal shaft (2) without interfering with the movement of the throw holding device (32). support. In addition, the angle indexing device (31) is configured for each crank throw (
Each time the shrink-fitting is performed in step 1), the journal shaft (2) is rotated at a predetermined angle, and each crank throw (1) is shrunk-fitted in sequence.
) The rotational direction angle between the two is the predetermined piping angle.

In the present embodiment described above, compared to the above-mentioned example using the vertical pit type shrink-fitting equipment, the vertical movement of the material to be shrink-fitted is small, and each crank throw (1
), it is possible to improve the accuracy of indexing the tube angle, so it is particularly advantageous when applied to shrink-fitting and assembling long and large cranks. In addition, in [Fig. 3], the slow holding device (3
2), but a plurality of throw retention devices (32) are arranged horizontally in parallel to provide a plurality of crank throws (32).
1) can also be shrink-fitted at the same time.

Finally, another embodiment of the method of the present invention will be explained with reference to FIG. 4.

[0030] FIG. 4 is a conceptual explanatory diagram of another embodiment of the method of the present invention, in which (a) is an explanatory diagram of the structure of the journal shaft before shrink-fitting, and (b) is a diagram illustrating the structure of the journal shaft after shrink-fitting. It is a figure showing a state. This embodiment is different from the one shown in Fig. 1 except that the journal shaft that is shrink-fitted to the crank throw is of an assembled type.
This is the same as the example shown in FIG. 1, and each part equivalent to that shown in FIG.

In this example, the journal shaft (42) into which each crank throw (1) is shrink-fitted is connected to a plurality of journals (42).
3) and the end journals (44) and (45) on the dummy shaft (
46), and is formed into a long shaft with a length corresponding to the entire length of the crankshaft to be manufactured. By the way, the journal of a large crankshaft is usually provided with a center hole as a circulation path for lubricating oil. In this example, the tie rod (
47), the journals and dummy shafts were connected and tightened to firmly integrate them.

[0032] Then, in the same manner as the example shown in [Fig. 1] or [Fig. 3], after shrink-fitting a number of crank throws (1) corresponding to the number of cylinders in series on the journal shaft (42), Unfasten the tie rods (47) and connect both arms (1) of each crank throw (1) as shown in figure (b).
b) Remove each dummy shaft (46) from between the two and move on to the finishing process.

In this example described above, the dummy shafts can be easily removed after shrink-fitting without cutting, and the material yield can be improved by reusing these dummy shafts. can be manufactured with higher productivity.

[0034] In addition, the above [Fig. 1], [Fig. 2] and [
In the three examples shown in Fig. 4, the crankshafts are each shown as having four cylinders, and each crank throw is shown as being located on the same plane, but this is for the purpose of simplifying the explanation, and the method of the present invention It goes without saying that the present invention can also be applied to the production of shrink-fit type crankshafts with other numbers of cylinders, and that each crank throw is shrink-fitted at a predetermined tube angle during actual shrink-fitting.

[0035]

Effects of the Invention As described above, in the method for manufacturing a shrink-fit type crankshaft according to the present invention, a plurality of crank throws are shrink-fitted to the same journal formed on a long shaft. Shrink-fitting with high straightness and precision can improve processing efficiency in post-processes.Furthermore, multiple crank throws can be shrink-fitted at the same time, greatly reducing the time required for shrink-fitting. You can significantly improve your sexuality.

[Brief explanation of the drawing]

FIG. 1 is a conceptual explanatory diagram of one embodiment of the method of the present invention,
(a) and (b) are explanatory diagrams of the intermediate material before shrink fitting, (c)
) is a schematic diagram illustrating the shrink-fitting process, and (d) is a diagram showing the state after shrink-fitting.

FIG. 2 is a conceptual explanatory diagram of another embodiment of the method of the present invention, in which (a) is an explanatory diagram of an intermediate material before shrink-fitting, (b) is a schematic diagram illustrating the shrink-fitting process; The figure (c) shows the state after shrink fitting.

FIG. 3 is a conceptual explanatory diagram of another embodiment of the method of the present invention.

FIG. 4 is a conceptual explanatory diagram of another embodiment of the method of the present invention, in which (a) is an explanatory diagram of the structure of the journal shaft before shrink-fitting, and (b) is a diagram showing the state after shrink-fitting. It is.

FIG. 5 is a conceptual explanatory diagram of a conventional method for manufacturing a shrink-fit type crankshaft, in which (a) and (b) are explanatory diagrams of an intermediate material before shrink-fitting, and (c) is an explanatory diagram of an intermediate material before shrink-fitting. It is a schematic diagram explaining a process.

[Explanation of symbols]

(1) --Crank throw (1a)--pin (1b)--arm, (1c)--Journal hole (2) --Journal shaft (3) --Shrink fitting equipment (3a)--Slow holding device (3b) (3c)--Axis lifting device α−−surplus part

Claims (1)

[Claims] 1. Manufacture of a shrink-fit type crankshaft that has a pair of arms on both sides of a pin, and connects and assembles a plurality of crank throws each having a through-hole for shrink-fitting in the arms by shrink-fitting them to a journal. In the method, a journal is formed into an elongated shaft passing through a plurality of crank throws in series, a plurality of crank throws are shrink-fitted to the journal, and the journal material present between a pair of arms of each crank throw is then A method for manufacturing a shrink-fit type crankshaft, characterized by removing.