JP2003278783A - Joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure wherein a required transmitting force is obtained, using a relatively simple arrangement without increasing a shaft diameter, and the joint is rotated at higher speeds than in conventional joint structures. <P>SOLUTION: Unstepped spline shafts 1a and 1b are inserted from both ends of a spline shaft 2 and engaged. The spline shafts 1a and 1b are formed with respective annular grooves 11a and 11b for fitting snap rings 3a and 3b therein and the spline sleeve 2 is formed with an annular groove 21 for fitting the snap rings 3a and 3b therein. Both side faces of the annular groove 21 are formed as tapered faces 211a and 211b which open toward an axis. With the tips of the spline shafts 1a and 1b abutting each other inside the spline sleeve 2, the snap rings 3a and 3b are caused to abut the tapered faces 3a and 3b as they increase in diameter, thereby causing the spline shafts 1a and 1b to be pressed by the elastic forces of the snap rings 3a and 3b in the direction to approach each other to prevent axial movement, while eliminating the need to form a hole through which to pass stepped levels and pins. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a joint structure for coaxially connecting shafts.

[0002]

2. Description of the Related Art For example, in the case of a product having a long shaft, in order to avoid an increase in the number of product types due to the difference in the length of the shaft, only the shaft portion has a structure which can be selectively lengthened by a joint. In many cases, a method of making one kind of complicated mechanical part is adopted.

Conventionally, a joint structure for such an application, that is, a joint structure for coaxially connecting shafts has been conventionally known.
The structures shown in FIGS. 5 to 10 are known.

The joint structure shown in FIGS. 5 and 6 is a so-called spline joint, and in the structure shown in FIG. 5, two spline shafts 41a and 41b are inserted from both sides of a common spline sleeve 42 and connected to each other. In addition, the spline shafts 41a and 41b and the spline sleeve 42 are connected to the spring pins 43a and 43, respectively.
The movement in the axial direction is prevented by b.
Further, in the structure shown in FIG. 6, the spline shaft 51
a and 51b are provided with a stepped portion C at their tips, and splines are formed on the outer peripheral surface only on the tip side of the stepped portions and inserted into the spline sleeve 52 for connection, and the outer peripheral surfaces of the spline shafts 51a and 51b and The snap ring 53 is formed by forming annular grooves 511a, 511b and 521a, 521b on the inner peripheral surface of the spline sleeve 52, respectively.
a, 53b are fitted, and the snap rings 53a, 5
3b and the stepped portions of the shafts 51a and 51b are configured to prevent movement in the axial direction.

On the other hand, as joints other than spline joints,
As shown in FIG. 7, flanges 62a and 62b are formed at the tips of the shafts 61a and 61b.
A flange joint that is fastened with a bolt B in a state in which 62b is butted, and as shown in FIG.
The tip of b is processed into a rectangular cross section, and these are processed into a square pipe 72.
A structure for transmitting rotation by inserting into a tube, and further, as shown in FIG. 9, a so-called propeller tube welding structure in which shafts 81a and 81b are welded to both ends of the tube 82, and also FIG. 10 (A). A cross-sectional view parallel to the axis
As shown in the sectional view taken along the line BB in FIG. 1B, a structure is used in which a key groove is formed in each of the shafts 91a and 91b and the sleeve 92 and the key 93 is inserted.

[0006]

By the way, each of the conventional joint structures described above has problems as described below. That is, according to the conventional spline joint, stress concentration occurs in the hole for inserting the spring pins 43a and 43b in the one shown in FIG. 5 and in the step C in the one shown in FIG. However, since it is necessary to increase the diameter of the shaft in order to strengthen the connected portion, the dangerous rotation speed (bending resonance point) decreases due to the increase in mass, and it becomes difficult to rotate at high speed.

Further, in the flange joint shown in FIG. 7, there is a problem that the flange portion has a larger diameter than in the case of the spline joint, and the dangerous rotation speed is lowered. Furthermore, in the structure using each tube shown in FIG. 8, when it is used at high speed rotation, there is a concern that runout due to imbalance may occur, and it is necessary to increase the rotating diameter in terms of strength compared to the spline joint. In the propeller tube welding structure shown in Fig. 9, the tube diameter must be increased in consideration of welding strength, and in the structure using the key shown in Fig. 10, in terms of transmission force, compared with the spline joint. Even if a joint structure other than the spline joint is adopted, such as a disadvantage, the dangerous rotation speed is lowered and it becomes difficult to rotate at a high speed.

The present invention has been made in view of the above circumstances, and it is possible to obtain a required transmission force without increasing the shaft diameter and therefore without increasing the mass under a relatively simple structure. Therefore, it is an object of the present invention to provide a joint structure capable of rotating at a higher speed than the conventional joint structures.

[0009]

In order to achieve the above object, the joint structure of the present invention is a joint structure for coaxially connecting shafts, and each shaft is provided with a step portion near the joint portion. In order to make spline shafts that do not have any of them, insert them from both ends of a common spline sleeve so that the tips of the spline shafts abut each other, and fit snap rings on the outer peripheral surface of each spline shaft. A ring groove is formed on the inner peripheral surface of the spline sleeve, and a common ring groove into which the snap rings are fitted is formed. Both side walls of the ring groove of the spline sleeve are opened toward the axial center side. Taper surface of each spline shaft so that each snap ring abuts the taper surface in the middle of diameter expansion with the tip of each spline shaft abutting inside the spline sleeve. Characterized by that the form (claim 1).

Here, in the joint structure of the present invention, it is preferable to employ a structure in which both ends of the inner peripheral surface of the spline sleeve are chamfered with slopes that are gentler than the taper surface (claim 2). can do.

The present invention basically employs a spline joint excellent in transmission force, and has a mechanism for preventing axial movement of each spline shaft and spline sleeve in the spline joint as in the prior art. It is intended to achieve the intended purpose by providing a mechanism that does not require a spring pin hole or a step portion in the spline shaft.

In the present invention, the shafts to be connected to each other are employed as spline shafts having no steps in the vicinity of the joints, and spline joints that are engaged with each other by a spline sleeve are used to prevent the shafts from moving in the axial direction. As a mechanism for doing so, as shown below, a mechanism is used that presses each spline shaft toward each other by utilizing the elastic force of the snap ring in the radial direction.

That is, an annular groove for fitting the snap ring is formed on the outer peripheral surface of each spline shaft, while the snap ring fitted in the annular groove of each spline shaft is fitted on the inner peripheral surface of the spline sleeve. Form a common annular groove. Then, with the side walls of the annular groove of the spline shaft being tapered surfaces open toward the axis, each snap ring is tapered while the diameter of the snap ring is expanded while the tip of each spline shaft abuts inside the spline sleeve. By being configured to abut against the surface, the elastic force when the snap ring is expanded is applied in the direction in which the spline shafts approach each other.

With this construction, the tips of the spline shafts are brought into contact with each other in the assembled state, and the tips are elastically pressed in a direction in which the tips are pressed against each other.
It is possible to reliably prevent each spline shaft from moving in the axial direction with respect to the spline sleeve. Moreover, stress concentration does not occur because it is not necessary to provide a through hole or a step on each spline shaft, and the position of the annular groove for the snap ring formed on the spline shaft is not a part to which the transmission torque is applied, Further, since the spline sleeve has no location where stress concentration occurs, it is possible to obtain a required transmission force without increasing the shaft diameter or the sleeve diameter. As a result, the mass increase due to the joint structure can be reduced as much as possible, and the dangerous rotation speed is not lowered, so that high-speed rotation is possible.

Further, as in the invention according to claim 2, the inner peripheral surface of the spline sleeve is chamfered on the inner peripheral surface at both ends to have a gentler slope than the tapered surface with which the snap ring abuts. When the snap ring is inserted into the annular groove and inserted into the spline sleeve, a special jig is used because the snap ring comes into contact with the chamfer and automatically reduces its diameter as the spline shaft is inserted. It is possible to insert the spline shaft with the snap ring into the spline assembly without using the spline shaft. In addition, since the chamfer has a gentler inclination than the tapered surface, when inserting the other spline shaft after inserting the one spline shaft, the snap ring may contact the chamfer and reduce the diameter. The force that moves the spline sleeve in the axial direction by force does not become larger than the force required for the snap ring fitted in the spline shaft inserted earlier to reduce the diameter beyond the tapered surface, When inserting the spline shaft later, the spline sleeve can be easily inserted and assembled without supporting the spline sleeve.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an axially parallel sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged view of part A thereof.

Two spline shafts 1a, each having an involute spline S formed on its outer peripheral surface,
1b has a uniform diameter with no step. Of these, one spline shaft 1a is a basic shaft, and the other spline shaft 1b is an extension shaft. In other words, in a product series consisting of multiple types with different shaft lengths,
A product having the shortest shaft is constructed by using only the basic shaft, and another product having a longer shaft is constructed by splicing the extension shaft as shown.

Now, the above two spline shafts 1
The a and 1b are inserted into the spline sleeve 2 formed by forming involute splines s with internal teeth having the same specifications as the involute spline S and the module on the inner peripheral surface, and are spline-coupled to each spline shaft 1a. , 1b, the three members 1a, 1b and 2 are integrated with each other in a state where the tips of the members 1a, 1b are in contact with each other.

On the outer peripheral surface of each spline shaft 1a, 1b, there are formed annular grooves 11a, 11b into which the snap rings 3a, 3b are fitted, and on the inner peripheral surface of the spline sleeve 2, there is also a snap ring. Three
An annular groove 21 into which a and 3b are fitted is formed.

Both side walls of the annular groove 21 of the spline sleeve 2 are tapered surfaces 211 that are inclined toward the axial center to open.
a and 211b, and these tapered surfaces 211
The distance between a and 211b is equal to the distance between each spline shaft 1a,
In relation to the annular grooves 11a and 11b formed in 1b, they are set as follows.

That is, each spline shaft 1a, 1
b is inserted into the spline sleeve 2 with the snap rings 3a and 3b fitted in the respective annular grooves 11a and 11b, and the tips of the snap rings 3a and 3b are in contact with each other. 211a, 2
11a and 211a so that the tapered surfaces 211a, 211
The distance between b and the distance between the annular grooves 11a and 11b from the tips of the spline shafts 1a and 1b are set.

Further, chamfers 22a and 22b, which are slanted faces that open toward the outside, are formed at both ends of the inner peripheral surface of the spline sleeve 2, respectively.
The angles α of 2a and 22b are equal to the tapered surfaces 211a and 211b.
Is smaller than the angle β of.

According to the above-described embodiment of the present invention, each spline shaft 1a, 1b has a spline sleeve 2
Since the respective snap rings 3a, 3b are in contact with the respective tapered surfaces 211a, 211b in the middle of the diameter expansion in a state where they are inserted into each other and their tips are in contact with each other, as shown in FIG. , 3b are in contact with the tapered surfaces 211a, 211b during the diameter expansion, the elastic force Fex of the snap rings 3a, 3b in the diameter expansion direction causes the snap rings 3a, 3b to move toward the tapered surface 211.
The force Ft pressing the a and 211b and the pressing force Fp in the direction to bring the spline shafts 1a and 1b closer to each other.
Is decomposed into. Therefore, each spline shaft 1a, 1
In the assembled state, b is always pressed in a direction in which they approach each other with their tips abutting each other, and axial movement of each spline shaft 1a, 1b relative to the spline sleeve 2 is reliably prevented.

In order to assemble the above embodiment of the present invention, the annular groove 1 of each spline shaft 1a, 1b is to be assembled.
One of the shafts, for example, the spline shaft 1a, is inserted into the spline sleeve 2 with the snap rings 3a and 3b fitted in the 1a and 11b, respectively.
At this time, the snap ring 3a comes into contact with the chamfer 22a formed at the end of the inner peripheral surface of the spline sleeve 2, so that the snap ring 3a is automatically reduced in diameter as the spline shaft 1a is inserted, and the spline is reduced. The diameter is expanded by being inserted into the sleeve 2 and fitting into the annular groove 21.

Next, in this state, the other spline shaft 1b is inserted from the opposite side. At this time, the snap ring 3b contracts into the spline sleeve 2 by abutting against the chamfer 22b in the same manner as described above. At this time, since the inclination angle β of each tapered surface 211a, 211b is larger than the inclination angle α of the chamfers 22a, 22b, the force acting on the spline sleeve 2 when the snap ring 3b is reduced in diameter by the chamfer 22b causes
The snap ring 3a of the spline shaft 1a inserted first does not come off from the annular groove 21, so that it is not necessary to particularly support the spline sleeve 2 when inserting the spline shaft 1b later, and the assembling work becomes easy. .

A point to be particularly noted in the above-mentioned embodiment is that each spline shaft 1a, 1b does not have a step or a partial large-diameter portion, which makes it possible to cut a spline gear from a straight round bar. Also, it can be manufactured only by processing the annular groove, and can be manufactured at low cost. In addition, each spline shaft 1a, 1b
Since there is no step or through hole in the shaft, the required torque can be transmitted without increasing the shaft diameter, and the dangerous rotational speed is not reduced. Further, the inner peripheral surface of the sleeve 2 only needs to be processed once for the annular groove 21 and for broaching the spline, and in this respect as well, the manufacturing cost can be kept low.

In the above embodiment, the two snap rings 3a and 3b are fitted in the single annular groove 21. However, as shown in FIG. 4, as shown in FIG. The annular groove 21 into two annular grooves 21
Snap ring 3 in each groove as a and 21b
You may make it a and 3b each fit. With this configuration shown in FIG. 4, it is possible to reduce the range in which the wall thickness of the spline sleeve 2 is thin.
The strength of the spline sleeve 2 can be increased and the abutting portions of the spline shafts 1a and 1b can also be connected to the spline sleeve
Since it is supported by, the rigidity of the connecting portion can be further improved.

Further, in the above embodiment, an example in which the involute splines are formed on the shafts 1a, 1b and the sleeve 2 has been shown, but the present invention is not particularly limited to this, and angular splines may be used. Of course good things.

Further, although the cross sections of the snap rings 3a and 3b are circular in FIGS. 1 to 4, it goes without saying that they may have a rectangular cross section.

Further, in order to prevent backlash between the spline sleeve 2 and the spline shafts 1a and 1b, the spline may be provided with a helix angle.

[0031]

As described above, according to the present invention, as a joint structure for connecting shafts to each other, a spline joint excellent in transmission force is adopted, and an annular groove formed on the outer peripheral surface of each spline shaft. Snap ring fitted in
The spline sleeve is configured to prevent axial movement between the spline shaft and the spline sleeve by being fitted in the annular groove formed on the inner peripheral surface of the spline sleeve, and both side walls of the annular groove of the spline sleeve are axially centered. As the taper surface is inclined so as to open toward the side, the snap ring is configured to abut on each taper surface in the middle of expanding the diameter, with the tip of each spline shaft inserted into the spline sleeve abutting. In the assembled state, the spline shafts are further pressed by the elastic force of the snap ring in a state in which the tips of the spline shafts are in contact with each other, so that the spline shafts can be reliably prevented from moving in the axial direction. Moreover, unlike the conventional spline joint structure, since it is not necessary to form a through hole or a step for penetrating the spring pin in each spline shaft, it is possible to reduce the mass increase due to the joint as much as possible. High-speed rotation is possible without lowering the number of rotations, and at the same time, it is easy to process and can be manufactured at low cost.

Further, as in the invention according to claim 2, by providing chamfered portions having a gentler inclination angle than the taper surface for abutting the snap ring on both ends of the inner peripheral surface of the spline sleeve, Assembly work is also facilitated.

[Brief description of drawings]

FIG. 1 is an axially parallel sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is an explanatory view of the operation of the embodiment of the present invention.

FIG. 4 is a cross-sectional view of an essential part of another embodiment of the present invention.

FIG. 5 is an axially parallel sectional view showing a structural example of a conventional spline joint.

FIG. 6 is an axially parallel sectional view showing another structural example of the conventional spline joint.

FIG. 7 is an axially parallel sectional view showing an example of a conventional flange joint.

FIG. 8 is a perspective view showing an example of a conventional joint using each tube.

FIG. 9 is an axially parallel sectional view showing an example of a joint using conventional propeller tube welding.

FIG. 10 is an axially parallel sectional view (A) and its BB sectional view (B) showing an example of a joint using a conventional key.

[Explanation of symbols]

1a, 1b Spline shaft 11a, 11b annular groove 2 spline sleeve 21 annular groove 211a, 211b Tapered surface 22a, 22b Chamfer 3a. 3b snap ring

Claims (2)

[Claims] 1. A joint structure for coaxially connecting shafts, wherein each shaft is a spline shaft having no step near the joint, and these are splined from both ends of a common spline sleeve. Of the spline shafts are inserted so that the tips of the spline shafts come into contact with each other, and the spline shafts are formed with annular grooves for fitting snap rings, and the inner surface of the spline sleeve has Form a common annular groove into which the snap ring fits,
Both side walls of the annular groove of the spline sleeve are tapered surfaces that open toward the axial center side, and with the tip of each spline shaft abutting inside the spline sleeve, each snap ring is expanded in the above-mentioned tapered surface. A joint structure characterized in that it is configured to abut against. 2. The joint structure according to claim 1, wherein both ends of the inner peripheral surface of the spline sleeve are chamfered with an inclined surface that is less inclined than the tapered surface.