JP4200594B2 - Cylinder shaft machining method and cylinder shaft - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of machining a cylindrical shaft that is used by being spline-fitted with a convex shaft, and to the cylindrical shaft. This cylindrical shaft is, for example, one of the shaft end portion of one shaft body constituting the telescopic shaft, the shaft end portion of the universal joint yoke, or the drive shaft of the tractor and the input shaft of various working machines pulled by the tractor. Provided at the shaft end portion.
[0002]
[Prior art]
In general, for example, when two shaft bodies are connected via a universal joint, the universal joint yoke and each shaft body may be spline-fitted, and in this case, for example, the shaft end portion of the yoke Is a cylindrical shaft having a female spline portion on the inner peripheral surface, and a shaft end portion of the shaft body is a convex shaft on which a male spline portion is formed.
[0003]
[Problems to be solved by the invention]
In such a yoke, if the female spline part of the cylindrical shaft collides with the male spline part of the convex shaft in the process of spline fitting the cylindrical shaft and the convex shaft, the edge of the female spline part may be deformed. There is. Since such deformation is not preferable, the present inventors tried to improve the strength against the deformation by subjecting the female spline portion of the cylindrical shaft to thermosetting treatment under various conditions. The thermosetting treatment was effective in improving the strength of the female spline part. However, it has been found that when the thermosetting treatment is performed, a shape distortion occurs in the female spline portion, so that the dimensional accuracy is not ensured and the fitting property with the male spline portion is lowered.
[0004]
Therefore, the present inventors have further advanced research. As a result, when the thickness of the cylindrical shaft is almost uniform among the cylindrical shafts of various shapes, the shape distortion amount of the female spline part is almost uniform in each part even if the thermosetting process is performed. There is no problem if it is managed so as to be within the range. However, when the cylindrical shaft has a deformed outer periphery, that is, when the wall thickness varies in the required area in the axial direction, the dimensional accuracy of the female spline cannot be secured because the amount of geometric distortion is not uniform in the axial direction. It has been found that post-processing is required, for example, the spline fitting property is lowered.
[0005]
Therefore, according to the present invention, in the cylindrical shaft machining method including the thermosetting treatment of the outer peripheral cylindrical shaft, the shape distortion amount of the spline fitting portion can be made uniform in the axial direction, and the dimensional accuracy of the female spline portion can be secured. It is an object of the present invention to provide a cylindrical shaft processing method for processing a cylindrical shaft and a cylindrical shaft using the cylindrical shaft processing method.
[0006]
[Means for Solving the Problems]
In the cylindrical shaft machining method of the present invention, in the method of machining a cylindrical shaft on which the convex shaft is spline-fitted, the cylindrical axis has a different outer diameter in the axial direction region than the other region. A step of forming a female spline portion, and a step of performing a thermosetting process comprising a high-temperature heating step and a rapid cooling step on the female spline portion of the cylindrical shaft, and in the process of thermosetting, the cylindrical shaft The amount of geometric distortion in the rapid cooling process by applying a heat equalization jig for equalizing or almost equalizing the heat radiation of each axial part of the female spline part to the region where the outer diameter of the female spline part is small Is equalized in each part in the axial direction .
[0007]
In the cylindrical shaft machining method, preferably, the thermosetting process is induction hardening.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on embodiments shown in the drawings.
[0009]
Although the cylinder shaft machining method of the present embodiment will be described in detail later, in short, in the method of machining a cylinder shaft on which the convex shaft is spline-fitted, the outer peripheral axial required region is different in diameter from other regions. A step of forming a female spline portion on the cylindrical shaft, and a step of performing a thermosetting process on the female spline portion of the cylindrical shaft. For the region where the outer diameter of the female spline is small, a heat dissipating jig for equalizing or substantially equalizing heat dissipating in each axial part of the female spline part is applied. In this thermosetting process, in particular, the required area in the axial direction is a fitting surface on which another member (for example, corresponding to a support unit C in FIGS. 5 and 6 described later) is attached on the outer periphery of the cylindrical shaft. It becomes. Note that the term radiating jig used here also equalizes the difference in heat capacity of each part in the axial direction, so it can also be referred to as a heat capacity equalizing jig. In other words, if the materials are the same, it can also be said that it is a thickness equalization jig for equalizing the thickness of each part in the axial direction. In order to equalize each part in the axial direction, it can be rephrased as a jig for equalizing the amount of shape distortion, and it is not limited to its name, and as a result, the heat radiation of each part in the axial direction of the female spline part can be equalized. All of them are included, if any.
[0010]
FIG. 1 shows a cylindrical tube shaft 10 processed by the tube shaft processing method of the above-described embodiment, and a columnar convex shaft 20 that is spline-fitted thereto.
[0011]
The cylindrical shaft 10 has a deformed outer periphery in which the outer periphery has a stepped shape between a small-diameter portion 11 in which the axial required region is thin, and a large-diameter portion 12 that is thicker than the small-diameter portion 11. It has the female spline part 13 to which the thermosetting process was performed by induction hardening etc. in the direction.
[0012]
The convex shaft 20 has a male spline portion 21 on the outer periphery, and is fitted to the cylindrical shaft 10 by spline fitting so that both the spline portions 13 and 21 are fitted to the cylindrical shaft 10 (spline fitting). ) So as to be slidable in the axial direction and connected in a synchronously rotating manner in the circumferential direction.
[0013]
Since the tube shaft 10 is subjected to thermosetting treatment, the female spline portion 13 of the tube shaft 10 collides with the male spline portion 21 of the convex shaft 20 in the process in which both the spline portions 13 and 21 are spline-fitted. However, the one-side opening edge is not deformed.
[0014]
Further, the strain amount of the female spline portion 13 generated by the thermosetting process is almost constant in the axial direction, and the dimensional accuracy in spline fitting can be secured.
[0015]
Hereinafter, the cylindrical shaft machining method of the present embodiment for machining into such a cylindrical shaft 10 will be described in detail.
[0016]
Although the cylindrical shaft 10 has a small diameter portion 11 and a large diameter portion 12 on the outer periphery, the small diameter portion 11 has a small heat capacity because it is thin. Since the large diameter part 12 is thick, its heat capacity is large. Therefore, in the case of the cylindrical shaft 10 having such an outer periphery, there is a difference in the heat capacity of each part in the axial direction, that is, there is a difference in heat dissipation. Therefore, if the female spline part 13 is formed and immediately subjected to the thermosetting treatment, The amount of geometric distortion of each part in the axial direction of the female spline portion 13 due to the curing process becomes non-uniform, and it is difficult to ensure the dimensional accuracy. Therefore, in the embodiment, after the female spline portion 13 is formed, the heat dissipation jig 30 is applied to the small diameter portion 11 in order to eliminate the difference between the two heat capacities and equalize or almost equalize the heat dissipation. The heat dissipation of the respective parts in the entire axial direction including the heat dissipation jig 30 is equalized or substantially equalized.
[0017]
And in this state, the thermosetting process of the female spline part 13 is performed. As a result, in the cylindrical shaft 10 after the heat radiation jig 30 is removed, the amount of distortion in the female spline portion 13 is uniform everywhere in the axial direction, and thereby it is possible to ensure the dimensional accuracy of the female spline portion 13. It has become.
[0018]
Hereinafter, this will be described in detail with reference to FIG.
[0019]
As shown in FIG. 2A, a forged cylinder shaft 10 having a circular cross section and an outer periphery having a different diameter in the axial direction, that is, a small diameter portion 11 and a large diameter portion 12 is prepared. In the cylindrical shaft 10, the thickness between the inner peripheral surface of the through hole and the outer peripheral surface of the cylindrical shaft 10 is thin at the small diameter portion 11 and thick at the large diameter portion 12.
[0020]
Next, as shown in FIG. 2B, the female spline portion 13 is formed by performing broaching on the inner peripheral surface of the through hole of the cylindrical shaft 10.
[0021]
After forming the female spline portion 13, as shown in FIG. 2C, an annular heat radiating jig 30 is applied to the small diameter portion 11 to equalize the heat capacity in each axial portion as a whole. The equalization of the heat capacity will be described. If the material of the heat radiating jig 30 is the same as that of the cylindrical shaft 10, the heat radiating jig 30 has an axial length that matches the axial length of the small diameter portion 11 and the difference between the large diameter portion 12 and the small diameter portion 11. And a thickness corresponding to. Therefore, in the state of FIG. 2C, the heat capacities in the respective axial portions of the female spline portion 13 of the cylindrical shaft 10 are equalized.
[0022]
Note that the material of the heat dissipation jig 30 may be different from that of the cylindrical shaft 10. In this case, the thickness of the heat radiating jig 30 is not limited to the difference in thickness between the large diameter portion 12 and the small diameter portion 11. In short, the heat capacity as a whole may be uniform.
[0023]
In this manner, with the heat radiation jig 30 applied to the outer peripheral surface of the small-diameter portion 11, the female spline portion 13 is subjected to thermosetting treatment by induction hardening or the like. By this thermosetting treatment, the strength of the female spline portion 13 is improved, and deformation of the one side opening edge due to the collision can be prevented.
[0024]
The thermosetting process for the female spline part 13 includes a high-temperature heating process and a rapid cooling process. In this rapid cooling process, a shape distortion occurs in the female spline part 13. In this case, as described above, since the heat capacity of each part in the axial direction of the cylindrical shaft 10 is substantially equal, the amount of this geometric distortion is the total thickness of the cylindrical shaft 10 including the heat radiation jig 30 at the time of the thermosetting process. Became uniform in each part in the axial direction. Specifically, in the conventional processing method, the difference between the geometric distortion amount at the small diameter portion 11 and the geometric distortion amount at the large diameter portion 12 (strain amount difference) with respect to a tolerance width of 0.06 mm (per diameter). However, in the embodiment, the difference in distortion amount is equal to or less than the tolerance width, and the required dimensional accuracy of the female spline portion 13 of the cylindrical shaft 10 can be ensured. When the female spline portion 13 is formed, the shape and dimensions of the teeth and grooves are managed so as to have a dimensional tolerance required as a product in a state where distortion occurs.
[0025]
Next, as shown in FIG. 2D, by removing the heat radiating jig 30, the deformed outer peripheral cylindrical shaft 10 having the small diameter portion 11 and the large diameter portion 12 shown in FIG. 1 is obtained.
[0026]
The cylindrical shaft machining method of the present embodiment is particularly useful for machining a cylindrical shaft having a structure as will be described next with reference to FIGS.
[0027]
10a is a cylinder axis and 20 is a convex axis.
[0028]
The cylindrical shaft 10a is formed with an enlarged tapered surface 14 at one open end of the inner peripheral surface thereof, and slopes 15 that are obliquely curved on both circumferential sides of the tip end portion of each spline tooth of the female spline portion 13. The shape of the tip portion of the spline teeth is formed in a substantially V shape in plan view. In addition, in the inclined surface 15, the two inclined surfaces 15 each located in the spline groove side become a pair, and it has the shape curved in the shape of a mortar. A fan-shaped depression 16 connected to the pair of inclined surfaces 15 located on the spline groove side is formed in a region on the tip side of each spline groove of the female spline portion 13 on the diameter-expanded tapered surface 14. Yes. The V-shaped tooth tip of each spline tooth is not sharply pointed, but is formed flat along the circumferential direction. This flat portion is referred to as a flat portion 17. The circumferential width B of the flat portion 17 is set within a range of 0.5 to 3 mm, preferably 1 mm. The flat portion 17 may be a rounded R surface. Note that the two pairs of inclined surfaces 15 and 15 and the depressed portion 16 formed at the tip portion of the spline groove serve as a guide surface for correcting a phase shift when the convex shaft 20 is connected.
[0029]
And this cylindrical shaft 10a has a deformed outer periphery whose outer peripheral surface has a small-diameter portion 11 and a large-diameter portion 12, but its production is the same as the case of the cylindrical shaft 10 described above. Description is omitted. The convex shaft 20 has a tapered surface 22 at the tip of each spline tooth of the spline portion 21.
[0030]
In the case of the cylindrical shaft 10a described above, the shaft centers of both the shafts 10a and 20 are shifted in the connection process with the convex shaft 20, or the phases of the spline portions 13 and 21 of both the shafts 10a and 20 are shifted. However, misalignment and phase shift are automatically and smoothly corrected without bothering humans. When the shaft centers of both shafts 10a and 20 are shifted, the tapered surface 14 of the cylindrical shaft 10a and the tapered surface 22 of the spline teeth of the convex shaft 2 are brought into contact with the operation of abutting the shafts 10a and 20. When in contact with each other, the tapered surface 14 of the cylindrical shaft 10a acts so as to convert the axial driving force of the convex shaft 20 into a force that radially displaces the axial center of the cylindrical shaft 10a and the axial center of the convex shaft 20. Will match.
[0031]
The cylindrical shaft 10a can be used as a coupling for connecting the convex input shaft 3a of the work machine 3 to the drive shaft 2a of the tractor 2 shown in FIG. 5, for example. Specifically, the cylindrical shaft 10a is integrally provided at the shaft end of the yoke 2c of the cross joint 2b attached to the free end of the drive shaft 2a of the tractor 2.
[0032]
In the example shown in FIG. 4, in order to be able to automatically connect the drive shaft 2a of the tractor 2 and the input shaft 3a of the work implement 3 without manual intervention, the work shaft 2 is provided on the tractor 2 side. An arm unit A that draws the machine 3, a locking unit B that is provided on the work machine 3 side and is locked to the arm unit A, and one yoke of the cross joint 2b that is provided on the arm unit A of the tractor 2. And a support unit C which supports the 2c so as to be tiltable and radially displaceable while being rotatable in a substantially horizontal posture.
[0033]
For example, as shown in FIG. 5, the support unit C includes an annular frame 4 fixed to the arm unit A of the tractor 2, a self-aligning ball bearing 5 attached to the annular frame 4, and the self-aligning ball. The bearing 5 is composed of three coil springs 6 that hold the bearing 5 in a substantially central position of the annular frame 4. The annular frame 4 includes a pair of annular plates 4a and 4b, and an inner cylinder 4c and an outer cylinder 4d that are sandwiched between the annular plates 4a and 4b and arranged radially inward and outward. The inner cylinder 4c is slidable in the radial direction. Three hollow bolts 4e for adjusting the compression amount of the coil spring 6 are screwed at three places on the circumference of the outer cylinder 4d.
[0034]
If the cylindrical shaft 10a is used as a coupling for coupling the tractor 2 and the work machine 3, the phase shift correction function by the cylindrical shaft 10a becomes extremely effective, and the drive shaft 2a of the tractor 2 and the work machine 3 are effective. It is possible to greatly contribute to further smoothing the connecting operation with the input shaft 3a.
[0035]
【The invention's effect】
In the cylindrical shaft machining method of the present invention, or not a so axial thermal capacity of the female spline portion is a step of heat curing treatment is equalized, the shape distortion of the female spline portion by heat curing treatment, axially everywhere It becomes uniform. As a result, the female spline portion of the cylindrical shaft is prevented from being deformed at the opening edge when fitted with the male spline portion of the convex shaft, and the amount of distortion in the female spline portion is uniform everywhere in the axial direction. It is possible to secure the dimensional accuracy of the spline part and improve the spline fitting property with the convex shaft.
[0036]
In the cylindrical shaft processing method, when the thermosetting process is induction hardening, the outer peripheral surface of the cylindrical shaft is not thermoset. Different diameter processing is possible and preferable.
[Brief description of the drawings]
1 is a perspective view of a cylindrical shaft processed by a cylindrical shaft processing method according to an embodiment of the present invention and a convex shaft that is spline-fitted thereto; FIG. 2 is a cross-sectional view for explaining the cylindrical shaft processing method of FIG. 3 is a cross-sectional view of another cylindrical shaft to which the processing method of the embodiment is applied. FIG. 4 is a perspective view of the cylindrical shaft of FIG. 3 and a convex shaft that is spline-fitted thereto. Side view showing an example in which the shaft is a coupling for connecting the tractor and the work machine. FIG. 6 is a vertical side view showing the support unit in FIG.
DESCRIPTION OF SYMBOLS 10 Cylinder shaft 11 Small diameter part 12 of a cylinder axis Large diameter part 13 of a cylinder axis Female spline part 20 of a cylinder axis Convex axis 21 Male spline part 30 of a convex axis

Claims (4)

In a method of processing a cylindrical shaft in which a convex shaft is spline-fitted,
A step of forming a female spline portion for a cylindrical shaft whose outer diameter in the axial direction required region is different from that of the other region;
Performing a thermosetting treatment comprising a high-temperature heating step and a rapid cooling step on the female spline portion of the cylindrical shaft;
Including
In the heat curing process, a heat equalizing jig for equalizing or substantially equalizing heat dissipation in each axial part of the female spline portion is applied to a region where the outer diameter of the cylindrical shaft is small. By equalizing the amount of geometric distortion in the rapid cooling step in each part in the axial direction,
A cylindrical shaft machining method. The cylindrical shaft machining method according to claim 1,
A cylindrical shaft machining method, wherein the thermosetting process is induction hardening. In the cylindrical shaft where the convex shaft is spline-fitted,
Processed by the cylindrical shaft processing method according to claim 1 or 2,
A cylinder shaft characterized by that. The cylindrical shaft according to claim 3,
On the other hand, at the opening end, a guide surface for correcting a phase shift at the time of connection with the convex shaft is provided.
A cylinder shaft characterized by that.

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