JPS5839243B2 - Crankshaft and its manufacturing method - Google Patents

Description

[Detailed description of the invention] In mechanical devices that must convert rotary motion into linear motion, or vice versa, linear motion into rotary motion, such as internal combustion engines, compressors, piston-type pumps, etc. A linear drive shaft supported by a motor and having one or more eccentric journals is often used as a motion conversion mechanism.

A connecting rod mounted on an eccentric journal by a bearing and having a piston at its opposite end is driven in a linear direction by the eccentric journal of a crankshaft rotating in a cylinder, for example.

Crankshafts of conventional construction have been cast or forged products in which journals and webs are integrally formed.

This conventional crankshaft has a very complex shape due to various webs, notches, and radii, making it extremely difficult to determine the internal stress of the shaft, resulting in unknown stress in the stress concentration area. In order to compensate for this stress, the thickness of the shirt tom and journal parts was made larger than necessary.

Efforts have also been made to manufacture crankshafts by attaching eccentric journals to long shafts.

However, this increased the complexity of the cast monolithic crankshaft geometry and did not result in any improvement in the stress analysis problem.

Therefore, in such a manufacturing method, a comparable amount of material was used as in a cast shaft, and the only advantage was the omission of the casting step.

The increased man-hours associated with the complicated manufacturing process overshadowed this advantage, making this method uneconomical for producing crankshafts.

This invention aims to provide a crankshaft and its manufacturing method that can greatly reduce manufacturing man-hours, enable accurate stress analysis, and eliminate the use of excess material beyond what is necessary for strength. It is.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

In Figure 1, the straight cylindrical shaft 71/11 is 4
It is made of a general bar material or a round bar forged product made of an alloy such as 130 steel.

The shaft portion 11 is cut from a bar material containing a suitable alloy and then milled to approximately the required length, and the cylindrical surface portion 12 is further reduced in diameter by primary processing.

On the other hand, the higher shoulders 13 to 16 are left in their 11 state.

The shoulders 13-16 are located on the periphery of the shaft portion 11.

The shaft portion 11 was originally a 3-cylinder mud pump.
Although designed to manufacture crankshafts for use in plex pumps (Plexmud pumps), the principles and techniques involved and described in this process are suitable for manufacturing crankshafts of other types with one or more journals. It can also be applied to manufacturing.

In Figures 2a and 2b, a typical high-rank shaft journal used in the shaft section 11 is shown.

2a, the circular journal disk 17 is made from a mild steel plate, such as A36, of suitable thickness.

The disk 17 is cut out from a plate material by appropriate means such as cutting or cutting.

The disk 17 is cut to have a cylindrical outer periphery 18, the center of which is a point C.

A circular hole 19 centered at point D is cut in the disk 17, into which one of the shoulders 13-16 of the shaft portion 11 is fitted.

Point D is radially eccentric from point 0 by a predetermined distance T, which distance T determines the stroke of the crankshaft journal.

FIG. 2b is a cross-sectional view taken along line B--B of FIG. 2a through center points C and D.

FIG. 2b shows the formation of an inclined shoulder 20 at the corner edge of the hole 19.

An inner shoulder portion 21 is formed on the inner periphery of the hole 19 so as to protrude from the inclined shoulder portion.

The sloping shoulder 20 of the bore 19 facilitates the press fit of the journal disk 17 into the crankshaft section 11 and forms a groove for welding the disk to the shoulders 13-16 of the shaft section.

The thickness of the journal disk 17 is from the shoulder portion 13 of the shaft portion.
The width is substantially the same as that of 16.

Naturally, the width of the shoulders 13 to 16 is adapted to the thickness of the disk 17 during the cutting process of the shaft.

Further, when machining the hole 19 in the disk, the diameter of the hole is made slightly smaller than the outer diameter of the disk mounting portion of the shaft portion.

As a result, the fit between the disk and the shoulder of the shaft portion is an interference fit, and appropriate pressing force using a hydraulic press or the like is required to fit the disk into the corresponding shoulder on the shaft portion.

Such press-fitting increases the strength of the crankshaft and also facilitates its manufacturing operation.

Figures 3a and 3b show a typical construction of a gear plate 22 attached to the shaft part 11, which gear plate is pressed into the shoulder 15.

The structure of gear plate 22 is similar to journal disk 17.

The gear plate 22 is cut out from a steel plate and is formed as a disk having its center at point P.

The disk 22 has a circular hole 23 into which the shoulder of the shaft portion 11 is inserted.

The shaft hole 23 is located at the center of the gear disc 22, and its center coincides with the center point P of the disc 22.

A plurality of holes 24 are bored in the disk 22 on the radially outer side of the hole 23.

These holes 24 are originally for manufacturing convenience, but
Besides that it helps reduce the weight of the crankshaft structure without compromising its strength.

A slanted shoulder 26 is formed at the corner edge of the shaft hole 23, which allows the annular shoulder 2 to protrude radially inward.
6 is formed.

The diameter of the hole 23 is slightly smaller than the outer diameter of the shoulder 15, and the diameter of the hole 23 is slightly smaller than the outer diameter of the shoulder 15.
2 is press-fitted into the shoulder portion 15 using a press, the fit between the two becomes an interference fit.

The diameters of the outer shoulders 13 and 16 are moderately smaller than the diameters of the inner shoulders 14 and 15;
The upper inner disc is adapted to be able to pass through the shoulders 13 and 16 without being jammed by them.

The shaft hole diameter of the discs mounted on shoulders 14 and 15 is larger than the outer diameter of shoulders 13 and 16, but slightly smaller than the diameter of the shoulder into which these discs are to be press fit.

4a and 4b show the shape of the crankshaft in the previous stage in a partial sectional view, in which the three journal discs 17a, 17b and 17c and the gear plate 22 are all located on the shaft section 11, respectively. Press-fitted into the shoulder.

FIG. 4b shows the position of the eccentric discs on the shaft and the eccentric relationship of these discs to each other.

In the case of three-mode operation, the eccentric directions of the journals are preferably offset from each other by 120°.

FIG. 4b shows an eccentric disk 17a on the shaft 11.

A preferred example of the arrangement of b and C is shown.

In this front view seen in the axial direction, the two disks are drawn with broken lines in perspective.

The gear disc 22, in which the shaft hole is located at the center, is of course not eccentric with respect to the shaft 11.

The groove formed by the inclined surface of the corner edge of the shaft hole of each disk is filled with a weld W, thereby connecting each disk to its respective shaft shoulder.

5 and 6 show the completed crankshaft in its assembled state with the associated parts of a three-cylinder pump operated by the crankshaft.

In the crankshaft shape shown in FIG. 5, the gear disc 22
Both sides of the annular portion near the outer periphery are cut to form an annular flange portion 27, and a large number of bolt holes 28 are bored in this flange portion.

An annular gear ring 29 having a large number of gear teeth on its outer periphery and an annular flange 31 protruding radially inward is attached to the gear disk 22.

The inner flange 31 has a number of bolt holes 32 drilled in conjunction with the bolt holes 28.

Further, the inner diameter of the flange 31 is the portion 27 of the disc 22.
It is designed to exactly match the inside diameter of the

This causes the flange 31 to fit into the cut recess forming the shoulder 27.

Bolts 33 are located in mutually matching bolt holes 28 and 32.
is inserted, and by tightening the nut 34, the gear ring 29 is firmly fixed to the gear disc 22.

The gear disk 22 attached to the shaft 11 has gear teeth 30
constitute means for driving a crankshaft, which also drives a connecting rod connected thereto by means of an eccentric journal 17.

A pump piston is attached to the other end of the connecting rod.

Since the construction of the eccentric journal and the attachment of the connecting rod thereto are essentially the same for each journal, one journal will be described below on behalf of the others.

In FIG. 5, a pair of bearing clamp rings 36 and 37 are attached to the side surface of a disc 17a on the shaft 11 by bolts 35 screwed into the discs 17a.

These rings hold the inner bearing race 38 in place on the outer circumference of the disc 17a.

A connecting rod having a generally circular end 39 is mounted in place of and surrounding the disc 17a.

Connecting rod end 39 has an inwardly projecting shoulder 40 along one side for mating with outer bearing race 41 .

The retaining ring 42 is attached to the connecting rod end by bolts 43 that pass through it and are screwed into the connecting rod end 39.

Ring 42 and shoulder 40 cooperate to retain outer bearing race 41 within connecting rod end 39.

A large number of cylindrical rollers 44 are arranged between the bearing races 38 and 41.
is housed so that it can be rotated.

Both ends of the crankshaft 11 are rotatably supported in a three cylinder pump housing 45 by roller bearing assemblies 46.

The bearing assembly consists of an end plate 4 attached with a number of bolts 48.
7 to the crankshaft.

FIG. 6 is an axial front view, partially in section, of the completed crankshaft/connecting rod assembly.

In FIG. 6, the position of the eccentric journal 17c is shown superimposed on the position of the gear ring 29 on the gear disc 22 with respect to the shaft 11.

The connecting rod end 39c is rotatably mounted on the eccentric disk 17c by a number of rollers 44c.

In operation of the crankshaft assembly in a three cylinder pump, rotational movement of the crankshaft is obtained by applying a force to the crankshaft through the ring gear 29 and the gear disc 22.

The shaft is rotatably supported within the pump housing by a bearing 46 and rotates within the bearing 46 when a force is applied to the gear 22.

As the shaft rotates, the eccentric journal 17, the connecting rod end of which is rotatably coupled by a bearing 44, rotates.

The eccentric movement provided by the rotation of the eccentric journal 170 causes the connecting rod within the pump housing to reciprocate, which causes linear movement of the pump piston connected to the connecting rod.

This linear movement of the piston produces the pumping action of the pump assembly.

As is clear from the above, the crankshaft of the present invention has a relatively simple structure, but is extremely strong and has little stress concentration.

When designing this crankshaft, very few parameters are required, and stress analysis of the shaft is very simple.

Stress analysis is carried out by calculating or experimentally measuring the stresses in a simple cylindrical shaft section 11, or alternatively by calculating the stresses generated by the torsional action of the journal disk.

Press-fitting the disc onto the shaft helps relieve stress in the shaft due to non-torsional welding of the two.

It is best to heat the shaft to about 500° F1 after pressing it into the shaft using a disc press, and weld at this temperature.

Once welding is complete, the shaft and disc are heated to approximately 600"Ft and then allowed to cool.

Next, the crankshaft should be moved approximately 120 degrees in the welded distortion area.
Heat to 0'Ft to relieve stress and hold for about 8 hours.

After stress relief, 4th a. The shaft in the state shown in Figure 4b is finished into the final shape shown in Figure 5.

No casting process is required in manufacturing the crankshaft of the present invention.

All components of the shaft are simple and straightforward and can be easily formed from fairly standard basic materials such as forged bar and sheet steel.

As a result, this shaft is lighter, cheaper, and stronger than conventional shafts.

Although this invention has been described based on a suitable embodiment in order to provide a basic understanding of the invention, it will be understood that various modifications may be made without departing from the essence of the invention.

For example, although bars and plates have been described as basic structural materials, it is clear that suitable materials having other basic shapes or configurations may be used.

That is, the cylindrical shaft portion may be cast or forged.

Similarly, instead of cutting a circular section from a plate to form a journal disk, the circular section may be cut from a large diameter bar.

Further, the shaft 11 may be configured as a smooth cylindrical shaft without forming the shoulders 13 to 16.

These shoulders are originally intended to facilitate assembly.

When creating an interference fit between the journal disk and shaft, it is easier to make the majority of the shaft smaller than the journal area.

This allows the journal disk to be easily slid into place 1 where it is to be pressed in with a press.

However, if the disks are press-fitted one by one along the longitudinal direction of the shaft, the protruding shoulder portion may not be provided.

Furthermore, another method for attaching the disk to the shaft is to form a key groove in the shaft and the disk and insert a key into this groove to perform key connection.

Therefore, the present invention includes all configurations that are modified from the configurations shown in the above-described embodiments without departing from the essential idea of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing a straight shaft portion of the crankshaft of the present invention. FIG. 2A is a front view of an eccentric journal disk used in the shaft of FIG. 1. FIG. 2B is a longitudinal cross-sectional view taken along line BB in FIG. 2A. FIG. 3A is a front view of a gear disk used in the shaft of FIG. 1. FIG. 3B is a longitudinal sectional view of FIG. 3A. FIG. 4A is a partially sectional side view of the crankshaft for a three-cylinder pump before finishing. FIG. 4B is a front view of FIG. 4A. FIG. 5 is a longitudinal sectional view of the completed three-cylinder crankshaft. 6 is a partially sectional front view taken along line 6-6 in FIG. 5. FIG. 11...Shaft, 13-16...Annular shoulder, 17...Journal disc means, 19.
...Shaft hole, 29...Gear drive means.

Claims (1)

Claims: 1. A cylindrical shaft of a desired length and diameter, eccentric journal disk means closely fitted to the shaft, and means for attachment between the shaft and the journal disk. A crankshaft characterized by: 2. The crankshaft according to claim 1, wherein the journal disk means is press-fitted into the shaft and then welded. 3. In the crankshaft as set forth in claim 1, the journal disk means consists of one or more disks, each disk having a hole for inserting the shaft at a position radially offset from its center. A crankshaft characterized by having a circular shaft hole. 4. In the crankshaft according to claim 3, the journal disk means is composed of three eccentric flat plates offset by 120 degrees from each other, and the crankshaft is a crankshaft fixed to the shaft portion. A crankshaft comprising a gear drive means for transmitting rotational motion to the crankshaft. 5 forming a cylindrical shaft portion of a desired length, forming one or more raised annular shoulders on the shaft portion, and further having a hole therethrough for receiving said shaft portion; A method for manufacturing a crankshaft or shaft, characterized in that one or more circular journal discs are formed, and the journal discs are fitted and fixed to the shoulders of the shaft portion. 6. A crank according to claim 5, characterized in that the hole in the journal disk is made slightly smaller than the annular shoulder of the shaft portion, and the journal disk is press-fitted into the annular shoulder of the shaft portion. How to manufacture the shaft. 7. A method for manufacturing a crankshaft, which is adapted to the method described in claim 5 and is characterized in that the shaft portion is cut out to a desired length from a round bar. 8. A method for manufacturing a crankshaft according to claim 5, wherein the higher shoulder portion of the shaft portion is formed by removing the shaft portion in an annular shape. 9. A method for manufacturing a crankshaft, which is directed to the method described in claim 5, and comprises making a journal disk by cutting out a circular plate from a plate material, and cutting out a hole eccentrically from the center of the disk. 10. A method of manufacturing a crankshaft according to claim 5, characterized in that the shaft portion is formed with another annular portion, and a gear disc is fitted into and fixed to this annular portion. 11. In the method described in claim 5, the shaft portion is made by cutting a round bar of a desired length from a solid rod having an outer diameter that is the same as or larger than the outer diameter of the shoulder portion that is one step higher. A method for manufacturing a crankshaft characterized by: 12 forming a cylindrical shaft of a predetermined length and diameter, forming eccentric journal disk means having shaft hole means therethrough, and fitting the disk means onto said shaft;
A method for manufacturing a crankshaft, characterized in that the disc means is fixed to the shaft. 13. A method for manufacturing a crankshaft, which differs from the method set forth in claim 12 and comprises making the hole means of the disc means smaller than the shaft, and press-fitting the disc means into the shaft. . 14 Form a cylindrical shaft of desired length and diameter, and further form three journal disks each having a radially offset hole for inserting the shaft, and insert these journal disks into the shaft. A crank for a gear-driven three-cylinder pump having three pistons and a connecting rod, which are fitted and fixed at intervals in the axial direction, and a circular gear is fixed to the shaft apart from the journal disk. How to manufacture the shaft. 15. A method for manufacturing a crankshaft, which comprises pressing the journal disks into the shaft while shifting the journal disks by 120 degrees from each other, by following the method set forth in claim 14.