JP3531364B2 - Joint between shaft and universal joint yoke - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The joint portion between the shaft and the yoke of the universal joint according to the present invention, for example, in a steering device, couples the end portions of various shafts constituting the steering device with the yoke of the universal joint. To use for.

[0002]

2. Description of the Related Art In a steering device for imparting a steering angle to the front wheels of an automobile, the movement of a steering shaft that rotates with the operation of the steering wheel is passed through a universal joint 1 of a cross shaft type as shown in FIG. And transmits it to the input shaft of the steering gear. The universal joint 1 is formed by connecting a pair of yokes 2 and 3 via a cross shaft 4. The four end portions provided on the cross shaft 4 are swingably supported at the tip portions of the yokes 2 and 3 via needle bearings provided in the bearing cups 5 and 5, respectively. .
Therefore, even if the centers of the two yokes 2 and 3 are not on the same straight line, the rotational force can be transmitted between the two yokes 2 and 3.

When a steering device is assembled using such a universal joint 1, for example, one yoke 2 (right side in FIG. 7) is attached to one shaft 6 such as a steering shaft.
Pre-joined and fixed to the end of the by welding or screwing,
The other yoke 3 (on the left in FIG. 7) is connected to the end of the other shaft 7. In order to perform such an assembling work, usually, after supporting the one shaft 6 on the vehicle body, the shaft 6 and the other shaft 7 are connected by the universal joint 1.

Therefore, among the yokes 2 and 3 of the universal joint 1 that constitutes the steering device, at least the other yoke 3 is a so-called side-mounting type in which connection work can be performed without moving the shaft 6 in the axial direction. Is preferred. For example, in the case of the universal joint 1 shown in FIG. 7, one yoke 2 is welded and fixed to the end portion of one shaft 6, while the other yoke 3 has a U-shaped cross section as shown in FIG. It has a base end portion 8 and is of a horizontal insertion type.

The base end portion 8 of the horizontal insertion type yoke 3 is 1
It is configured to include a pair of restraining plate portions 9a and 9b. These restraining plate portions 9a and 9b which are arranged apart from each other have their inner surfaces formed as restraining surfaces 10 and 10 which are parallel to each other. Then, the nut 11 is fitted in and fixed to the end portion on the opening side of the one holding plate portion 9a (on the left side of FIG. 8) to fix the screw hole 12
Is provided. Further, through holes 13 concentric with the screw hole 12 and having a larger diameter than the screw hole 12 are formed at the opening side end of the other restraining plate portion 9b. The screw hole 12 may be directly formed in the pressing plate portion 9a as shown in FIG. There is also a structure in which the nut 11 is not fitted and fixed to the yoke 3.

On the other hand, in the yoke 3 constructed as described above,
At least the tip of the shaft 7 to which the tip is connected has an oval shape as shown in FIG. That is, the outer peripheral surface of the tip portion of the shaft 7 is
By forming a pair of outer flat surfaces 14, 14 and bringing the outer flat surfaces 14, 14 into close contact with the restraining surfaces 10, 10 at the time of connection, rotation of the shaft 7 with respect to the yoke 3 is prevented.

When the end portion of the shaft 7 having the above-mentioned shape is connected and fixed to the base end portion 8 of the yoke 3 as described above, first, as shown by a solid line in FIG. The end portion is arranged on the opening side of the base end portion 8. From this state, for example, by rotating the yoke 3 about the cross shaft 4, the yoke 3 is swung clockwise from the solid line state to the chain line state in FIG. The end of the shaft 7 is inserted into the base end 8 of the yoke 3. The end of the shaft 7 may be inserted into the base end 8 of the yoke 3 by moving the end of the shaft 7 without moving the yoke 3. In any case, before inserting the end portion of the shaft 7 into the base end portion 8, the restraining bolt (not shown) is not inserted into the through hole 13.

As described above, the end portion of the shaft 7 is inserted into the base end portion 8 of the yoke 3, and the restraining surfaces 10 and 10 and the outer flat surfaces 14 and 14 (FIGS. 8 to 9) are opposed to each other. Then,
A male screw portion formed at the tip of a holding bolt (not shown) inserted in the through hole 13 is screwed into the screw hole 12 and further tightened. Based on this tightening, the pair of pressing surfaces 10,
The interval between the 10 is narrowed, and the restraining surfaces 10 and 10 and the outer flat surfaces 14 and 14 are in strong contact with each other, so that the distal end portion of the shaft 7 is coupled and fixed to the proximal end portion 8. still,
A notch 15 is formed on one edge of the end of the shaft 7 to prevent the shaft 7 from interfering with the rod portion of the holding bolt, and even if the holding bolt is loosened, The yoke 3 is prevented from coming off in the axial direction of the shaft 7.

[0009]

The yoke 3 and the shaft 7 are to be solved.
When tightening the tightening bolts screwed into the screw holes 12 of the yoke 3 in order to connect and fix the and, the pair of presser plate portions 9a and 9b forming the yoke 3 are set to the torque for tightening the presser bolts. Elastically deforms in proportion. On the other hand, in a narrow space such as the engine room, the pair of restraining plate portions 9a, 9a
order to the operation of inserting the end portion of the shaft 7 between b together easily performed, as shown in FIG. 11, the distance D ₁₀ of the clamping surfaces 10 to each other of the pair of restraining plate portions 9a, 9b Is
The width between the outer flat surfaces 14, 14 of the shaft 7 is larger than the width W _{7 of the} shaft 7 (D ₁₀ > W
₇ ) have.

Therefore, even if the holding bolts are tightened after the end portion of the shaft 7 is inserted between the holding plate portions 9a and 9b of the yoke 3, both holding plate portions 9a and 9b are tightened.
But until the difference (D ₁₀ -W ₇₎ amount corresponding elastic deformation between the interval D ₁₀ and the width W ₇ is the both clamping plates 9a, 9b outside the plane of the clamping surfaces 10 and the shaft 7 of The shaft 7 and the yoke 3 are not coupled and fixed because the shafts 14 and 14 do not come into close contact with each other. In other words, these restraining surfaces 10, 10
Until the outer flat surfaces 14 and 14 come into close contact with each other, the force consumed for elastically deforming each of the pressing plate portions 9a and 9b is
It is not used for connecting and fixing the shaft 7 and the yoke 3.

As a result, in order to sufficiently secure the coupling strength between the shaft 7 and the yoke 3, the torque for tightening the holding bolt must be increased considerably.
To tighten this holding bolt with a sufficiently large torque,
It is not preferable because it causes unnecessary plastic deformation of the yoke 3. On the other hand, if the torque for tightening the holding bolt cannot be sufficiently secured, the joint strength between the shaft 7 and the yoke 3 may be insufficient, and rattling may occur at the joint portion between these members 7 and 3. Occurs.

Further, even when the restraining bolts are tightened with a sufficient torque, the restraining surfaces 10, 10 of the pair of restraining plate portions 9a, 9b are likely to remain non-parallel to each other, and the restraining surfaces 10, 10 are respectively formed. And the outer planes 14, 14 of the shaft 7
It is easy for the and to hit one side (it is difficult to make uniform contact). As a result, rattling is likely to occur at the joint between the members 7 and 3. Such rattling gives an uncomfortable feeling to the driver who operates the steering wheel and is not preferable. The smaller the difference (D ₁₀ -W _7), Nakuseru such a problem, since the combination working the yoke 3 and the shaft 7 is cumbersome, can not be adopted.

The restraining surfaces 10 and 10 and the outer flat surface 1 are also provided.
In order to improve the adhesion with Nos. 4 and 14, the rigidity of the pair of restraining plate portions 9a and 9b is lowered, so that the plate thickness of the metal plate forming the yoke 3 is reduced or the hardness is lowered. Then, as the restraining bolts are tightened, the portions protruding from the outer flat surfaces 14, 14 at the tip end portions of the restraining plate portions 9a, 9b are likely to be plastically deformed in the directions toward each other. As a result of this plastic deformation, the pair of restraining plate portions 9a,
If the distance between the leading edges of 9b is smaller than the width W _{7 of the} shaft 7, the yoke 3 and the shaft 7 cannot be disassembled for inspection and repair. Further, when the hardness of the metal plate is reduced, a part of the yoke 3 (particularly, the restraining surfaces 10 and 10) is eroded due to a large torque applied to the connecting portion between the yoke 3 and the shaft 7 in use. If the tire is worn out, there is a backlash in the joint portion, and the driver feels uncomfortable.

Further, in the case of the conventional connecting portion between the shaft and the yoke of the universal joint, the allowable range of the tightening torque of the holding bolt is narrow, and the tightening torque can be controlled when the shaft and the yoke are connected. It was troublesome.
That is, the minimum value of the tightening torque is regulated from the viewpoint of preventing the backlash, and the maximum value is too large in view of the strength of the holding bolts, nuts, yokes, etc. to cause excessive plastic deformation of these members. Regulate as much as possible. In the case of the conventional structure, since the difference between the maximum value and the minimum value of the tightening torque is small, it is necessary to strictly manage the tightening torque in the automobile assembly line, which causes inefficiency of the assembly work. Was becoming. In view of such a situation, the present invention makes it possible to easily perform the work of connecting and fixing the shaft 7 and the yoke 3, and particularly, without strictly controlling the tightening torque of the holding bolt, these members 7, 3 The invention was made in order to prevent rattling at the joint portion.

[0015]

Binding portion of the shaft and the universal joint yoke of the present invention According to an aspect of, any, like the coupling portion of the yoke of a conventional shaft and universal joint described above, a shaft that rotates in use A pair of outer flat surfaces formed on the outer peripheral surface of the distal end portion of the shaft; and a yoke that has a proximal end portion that is open to the side and that constitutes a universal joint. A pair of restraint plate portions forming the base end portion, and a pair of restraint plate portions that connect the two restraint plate portions to each other at a portion opposite to the opening of the base end portion, with the side surface serving as a restraint surface facing each of the outer flat surfaces. Portion and the through holes or screw holes formed in both the restraining plate portions and concentric with each other, and with the through hole inserted therein, the male screw portion formed at the tip end thereof is screwed into the screw hole or nut. It is equipped with a holding bolt to make it fit.

Particularly, in the connecting portion between the shaft according to claim 1 of the present invention and the yoke of the universal joint, the pair of restraining members before tightening the restraining bolts are tightened. of the plate portion
The shape in the free state is suppressed by the inner surface of this pressing plate.
By forming the surface in a circular arc shape with a convex surface, the above 1
The distance between the restraining surfaces of the pair of restraining plate portions is narrow on the side close to the connecting portion and wide on the opening side of the base end portion where the through hole or the screw hole is formed. Then, at the time of tightening the holding bolt or the nut screwed with the holding bolt, the pair of outer flat surfaces and the respective holding surfaces first come into contact with each other on the side close to the connecting portion, and the holding bolt is tightened. The contact portion moves to the opening side of the base end portion with the progress of. In addition, the shaft according to claim 3 and the shaft
At the joint with the yoke of the existing joint
Before the tightening of the
The distance between the personnel is narrow on the side close to the connecting portion, and the
It is wide on the opening side of the base end where the screw hole is formed.
In addition to forming each of them, part of each restraining surface
The multiple convex parts are
It is formed at a plurality of places separated in the width direction of each restraining surface.
Then, use the above-mentioned holding bolt or screw with this holding bolt.
When tightening the nuts, tighten the nuts with the pair of outer flat surfaces
The surface is the tip surface portion of the convex portion existing on the side close to the connecting portion.
It will start contacting in a minute, and the tightening work of the holding bolt will proceed.
Along with the above, the tip end surface part of the convex part existing on the opening side of the base end part
The contact area is moved to the minute. Further, claim 5
At the joint between the shaft related to and the yoke of the universal joint
Before tightening the holding bolts,
Set the spacing between the restraining surfaces of the restraint plate on the side close to the connecting portion.
Narrow, of the base end that forms the through hole or screw hole
Wide on the opening side and formed respectively,
Of the continuous part between both widthwise edges and the base edges of both restraining plates
The surface is formed with a recess extending in the axial direction of the shaft.
It And with the above-mentioned holding bolt or this holding bolt
When tightening the screwed nuts,
The restraining surface first comes into contact with the side close to the connecting part, and
As the tightening work of the retaining bolt progresses, the base end is opened.
The contact area is moved to the mouth side.

[0017]

According to the connecting portion between the shaft of the present invention and the yoke of the universal joint configured as described above, the axial direction between the shaft and the yoke can be improved even if the tightening torque of the holding bolt is not strictly controlled. The holding power can be increased. That is, when tightening the holding bolt or the nut screwed with the holding bolt, first, of the holding surfaces of the pair of holding plates, the side closer to the connecting portion is the outer side of the pair formed on the shaft. Start suppressing the plane. Then, as the tightening work of the holding bolt or the nut screwed with the holding bolt proceeds, the contact portion moves to the opening side of the base end portion of the yoke. For this reason, the contact pressure between each of the restraining plate portions and the pair of outer flat surfaces increases at a relatively early time after the tightening of the restraining bolt or the nut screwed with the restraining bolt is started. Therefore, even with a relatively small tightening torque, the pair of outer flat surfaces and the restraining surfaces are brought into close contact with each other with sufficient contact pressure, and the coupling strength between the shaft and the yoke can be secured.

[0018]

DETAILED DESCRIPTION OF THE INVENTION right half section and Figure 2-3 of Figure 1, 請
Corresponding to Motomeko 1,2,4,5, a first example embodiment of the present invention, the left half portion and 5-6 of Figure 1, claim 3,
The 2nd example corresponding to 4 and 5 is each shown.
The feature of this example is that, as shown in FIG. 3, the pair of restraining plate portions 9a, 9b constituting the yoke 3 and the restraining surfaces 10a, 10b of the shaft 7 and the shaft 7 are formed by tightening the restraining bolts 17 called cam bolts. The outer flat surfaces 14 and 14 are in close contact with each other to ensure the bonding strength between the yoke 3 and the shaft 7. Since the structure and operation of the other parts are the same as those of the conventional structure described above, the illustration and description of the equivalent parts will be omitted or simplified, and the characteristic part of the present invention will be mainly described below. Further, as described above, the right half part of FIG. 1 shows the first example of the embodiment of the present invention, and the left half part shows the second example thereof. The yoke 3 constituting each example is
Except for a through hole for inserting the restraining bolt 17, it is symmetrical with respect to the center line α.

The base ends (the ends opposite to the opening of the base end 8 and the lower end in FIG. 1) of the pair of restraining plates 9a and 9b forming the base end 8 of the yoke 3 have arc-shaped edges. They are connected to each other by the connecting portion 16. Moreover, both widthwise end edges and the respective restraining plate portions 9a of the consolidated portion 16, the continuous portion of the base end edge of 9b to form the thin portions 18, 18, lowered these stiffness of each successive portions ing. Therefore, based on the tightening of the restraining bolt 17 and a nut (not shown), the pair of restraining plate portions 9a, 9b is provided.
When narrowing the gap between the front end portions (the opening side end portion of the base end portion 8 and the upper end portion of FIG. 1), the pair of holding plate portions 9a, 9
The distance between the restraining surfaces 10a and 10b of b is reduced by a relatively small tightening force. In addition, such thin-walled portions 18, 1
In order to form 8, in the illustrated example, recesses 19, 19 are formed on the inner surface of the continuous portion in the axial direction of the shaft 7 (the front and back directions in FIG. 1). Each of these recesses 19, 19
In addition to forming the thin-walled portions 18, 18, it prevents the inner surface of the base end portion 8 and the corner portions 20, 20 of the shaft 7 from interfering with each other when tightening the holding bolt 17 and the nut.

Of the pair of restraining plate portions 9a and 9b, the second example of the embodiment is shown. The overall shape of one (leftward in FIG. 1) restraining plate portion 9a in the free state is , (Except for the convex portions 21 and 21 described below). Further, a plurality of convex portions 21, 21 are provided at a portion of the restraining surface 10a which is the inner side surface of the one restraining plate portion 9a and which faces the outer flat surface 14 of the shaft 7. It is formed by plastically deforming a part of the. The protrusions 21, 21 may be embossed discontinuous in the axial direction of the shaft 7 (see FIG. 5 described later) or bank-shaped continuous in the axial direction (see FIG. 6 described later). See also). In any case, the height of the plurality of convex portions 21, 21 (the amount of protrusion from the restraining surface 10a) is set so that the outer flat surface 14 is abutted from the side close to the connecting portion 16.
In the state in which the side closer to 6 is raised appropriately, and the holding bolt 17 is sufficiently tightened, all the convex portions 2
The tips of 1 and 21 are made to abut against the outer flat surface 14. However, the direction of the one restraining plate portion 9a in the free state is inclined so as to move away from the center line α as it goes away from the connecting plate portion 16.

On the other hand, the pair of restraining plate portions 9a,
9b shows the first example of the embodiment, the overall shape of the other (right side in FIG. 1) of the restraining plate portion 9b in the free state is
The holding surface 10b, which is the inner side surface of the holding plate portion 9b, is formed in a circular arc shape in section, which is a convex surface. The shape of the restraining surface 10b may be a single curved surface, but in the illustrated example, it is a complex curved surface in which cylindrical surfaces having different radii of curvature are smoothly continuous. That is, as shown in FIG.
0b is the first cylindrical curved surface 22 having a relatively small radius of curvature R _1, and the portion from the middle part of the restraining surface 10b to the tip is a relatively large radius of curvature R ₂ (R
The second cylindrical curved surface 23 having ₁ <R ₂ ) is used.

By making the pair of restraining plate portions 9a and 9b have the above-mentioned shapes, in both the first and second examples, these 1 before the restraining bolt 17 is tightened. The distance between the restraining surfaces 10a and 10b of the pair of restraining plate portions 9a and 9b is narrow on the base end side near the connecting portion 16 and wide on the front end side which is the opening side of the base end portion 8. A through hole (not shown) for inserting the restraining bolt 17 is formed in the tip side portion of each of the restraining plate portions 9a and 9b, and the restraining bolt 17 is made to interfere with the shaft 7 in each of the through holes. It is designed so that it can be inserted without it. However, when the holding bolt 17 is rotated based on the tightening of the nut screwed to the male screw portion 24 provided at the tip of the holding bolt 17 which is inserted through these both holes, the holding bolt 17 is rotated at the intermediate portion of the holding bolt 17. The outer peripheral surface of the formed cam portion 25 having an elliptical cross section holds down the shaft 7 toward the inner peripheral surface of the connecting portion 16. Of the pair of concentric through holes formed in the pair of restraining plate portions 9a and 9b, one through hole has a relatively large diameter so that the cam portion 25 can be inserted, and the other through hole. The hole has a relatively small diameter so that the male screw portion 24 can be inserted therethrough.

According to the connecting portion between the shaft of the present invention and the yoke of the universal joint configured as described above, the shaft 7 and the yoke 3 are not particularly strictly controlled even if the tightening torque of the holding bolt 17 is not strictly controlled. The holding force over the base end portion 8 in the axial direction can be increased. That is, in order to connect the shaft 7 and the yoke 3, first, with the shaft 7 inserted in the base end portion of the yoke 3, the holding bolt 17 is attached to the tip portions of the pair of holding plate portions 9a and 9b. Insert into the through hole formed in.
Then, the male screw portion 24 protruding from the outer surface of any one of the restraining plate portions 9a (or 9b) at the tip portion of the restraining bolt 17
Then, screw the nut. Then, by tightening the nut while rotating it, the nut and the restraining bolt 1
The distance between the head 26 of 7 and the head 26
Between the pair of holding plate portions 9a and 9b, the tip portions of the pair of holding plate portions 9a and 9b are held together.

When tightening of the nut is started in order to hold the tips of the pair of holding plates 9a and 9b together as described above, first, the cam portion 25 is rotated based on the rotation of the holding bolt 17. Holds the shaft 7 on the inner peripheral surface of the connecting portion 16. As a result, the shaft 7 and the inner peripheral surface of the connecting portion 16 are in contact with each other at the portion shown in FIG. Further, the restraining bolt 17 is prevented from further rotating due to the engagement between the cam portion 25 and the shaft 7. When the nut is further tightened, the proximal end side of the restraining surfaces 10a, 10b of the pair of restraining plate portions 9a, 9b close to the connecting portion 16 has a pair of outer flat surfaces 14 formed on the shaft 7,
Start suppressing 14 In this state, the pressing surface 10
a and 10b and the outer flat surfaces 14 and 14 are the same as those shown in FIG.
Contact in parts.

When the nut is tightened further from this state, the contact portion between the restraining surfaces 10a and 10b and the outer flat surfaces 14 and 14 is the opening side of the base end portion 8 of the yoke 3 shown in FIG. Move to the part. Then, when the tightening torque of the holding bolt 17 based on the tightening of the nut becomes sufficiently large, the contact pressure of the'part becomes large, and conversely, the contact pressure of the part becomes small, and finally, The contact pressure at the and 'parts becomes almost zero.

As described above, the connecting portion between the shaft of the present invention and the yoke of the universal joint has the above-mentioned restraining plates at a relatively early time after the tightening work by the restraining bolt 17 based on the tightening of the nut is started. The restraining surfaces 10a of the parts 9a, 9b,
10b and a pair of outer flat surfaces 1 formed on the shaft 7
The contact pressure with Nos. 4 and 14 becomes large. Therefore, even with a relatively small tightening torque, the pair of outer flat surfaces 1
4, 14 and the respective restraining surfaces 10a, 10b are brought into close contact with each other by a sufficient contact pressure, so that the coupling strength between the shaft 7 and the yoke 3 can be secured. Moreover, with the tightening of the nut, the above 1
A pair of outer flat surfaces 14, 14 and the respective restraining surfaces 10a, 10b
Since the contacting part with moves to the tip side of the restraining plate portions 9a, 9b, each component does not plastically deform until the tightening torque for tightening the nut becomes considerably large.

FIG. 4 shows the results obtained by the inventor of the present invention through the experiments and the analysis by the finite element method based on the experiments to find the forces acting on the respective parts. In FIG. 4, the vertical axis represents the yoke 3.
The force F for holding the shaft 7 against the horizontal axis and the tightening torque P of the nut for the bolt 17 against the horizontal axis,
Shown respectively. Further, of the two two-dot chain lines drawn in parallel with the horizontal axis, the lower two-dot chain line a is a force F _min for securing the minimum coupling strength between the shaft 7 and the yoke 3,
The two-dot chain line (b) on the upper side represents the maximum force F _max that does not cause undesired plastic deformation in each component. Further, a thin solid line C drawn in the vicinity of the horizontal axis shows the holding force generated in the above portion by pressing the cam portion 25. As is clear from this solid line C, the holding force generated in this portion is extremely small, and it is not very useful for holding the shaft 7 with respect to the yoke 3.

Further, the thin solid line D at the upper right is shown in FIG.
The relationship between the tightening torque of the holding bolt and the force for holding the shaft 7 against the yoke 3 in the conventional structure shown in FIGS. As you can see from this solid line,
In the case of the conventional structure, the value of the torque P _min required to obtain the force F _min for ensuring the minimum coupling strength and the maximum force F _max that does not cause undesired plastic deformation in each component part. The allowable torque range P _al (= P _max −P _min ) that is the difference from the torque P _max that generates the torque is small.

On the other hand, the mountain-shaped broken line E is the structure of the present invention,
Based on the tightening of the nut that is screwed with the holding bolt 17,
The holding force of the shaft 7 with respect to the yoke 3, which is generated in the part ', is shown. Also, the thick solid line in the upper right portion shows the holding force of the shaft 7 with respect to the yoke 3, which is generated in the above-mentioned part based on the tightening of the nut screwed with the holding bolt 17. Furthermore, the two-dot chain line G on the upper right indicates the sum of the holding force generated in the'part and the holding force generated in the'part. Therefore, in the case of the structure of the present invention, the holding force of the shaft 7 with respect to the yoke 3 is increased by increasing the tightening torque of the nut so as to trace a plurality of straight lines having the bending points at points a, b and c in FIG. Increase with it.

As is clear from the relationship represented by the continuation of a plurality of such straight lines, in the case of the structure of the present invention, the torque P required to obtain the force F _min for ensuring the minimum coupling strength. _The allowable torque range P _al ′ (= P), which is the difference between the value of _min ′ and the torque P _max ′ that generates the maximum force F _max that does not cause undesired plastic deformation in each component.
_max' -P _min ') is large. Therefore, in the case of the coupling portion between the shaft and the yoke of the universal joint of the present invention, the coupling strength between the yoke 3 and the shaft 7 can be sufficiently secured without strictly controlling the tightening torque of the nut, and each component It is possible to avoid undesired plastic deformation of the member.

Next, FIGS. 5 to 6 show the overall shape of the yoke 3 constituting the second example of the embodiment of the present invention. The structure and operation of the connecting portion between the shaft and the yoke, in which the yoke 3 is incorporated, are as described above. The holding bolt used in the present invention does not necessarily have to be a cam bolt as shown in FIG. When the cam bolt is not used, it is possible to form a screw hole for screwing the holding bolt into any one of the holding plate portions 9a and 9b, or to fix the nut.

[0032]

Since the connecting portion between the shaft of the present invention and the yoke of the universal joint is constructed and operates as described above,
Even if the torque for tightening the holding bolts or nuts is not particularly increased, the shaft and the yoke can be securely coupled and fixed, and rattling can be less likely to occur even after long-term use. Also, since the allowable range of the torque is widened,
It is not necessary to strictly control this torque, and the work of connecting the shaft and the yoke becomes easy.

[Brief description of drawings]

FIG. 1 is a first to a first embodiment of the present invention with a center line as a boundary.
The base end of the yoke and the end of the shaft that form the two examples are
Sectional drawing shown in the state before tightening a restraint bolt.

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

FIG. 3 is a side view and a plan view of the retaining bolt.

FIG. 4 is a diagram showing a relationship between a tightening torque of a nut with respect to a holding bolt and a force for holding a shaft with respect to a yoke.

FIG. 5 is a perspective view showing an overall configuration of a yoke that constitutes a second example of the embodiment of the present invention.

FIG. 6 is a perspective view showing an overall configuration of a yoke of another example.

FIG. 7 is a side view showing a state in which an end portion of a shaft and a base end portion of a yoke are coupled to each other in a structure which is a target of the present invention.

8 is a sectional view taken along line BB of FIG.

FIG. 9 is a sectional view taken along the line CC.

FIG. 10 is a partial side view of a universal joint showing another example of a conventional structure.

FIG. 11 is a cross-sectional view showing the dimensional relationship between the base end of the yoke and the end of the shaft.

[Explanation of symbols]

1 universal joint A few yorks 4 cross axis 5 bearing cups 6, 7 shaft 8 base end 9a, 9b Suppression plate part 10, 10a, 10b holding surface 11 nuts 12 screw holes 13 through holes 14 outer plane 15 notches 16 Connection 17 Holding bolt 18 Thin part 19 recess 20 corners 21 convex 22 First cylindrical curved surface 23 Second cylindrical curved surface 24 Male thread 25 Cam section 26 head

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuhiro Saito 1-8-1, Sojamachi, Maebashi City, Gunma Nihon Seiko Co., Ltd. (56) References: Kaihei Hei 6-80092 (JP, U) Actual Kai 63-164682 (JP, U) Suguru 38-26979 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16D 1/06, 3/26

Claims (5)

(57) [Claims] Claim: What is claimed is: 1. A shaft which rotates during use, a pair of outer flat surfaces formed on the outer peripheral surface of the distal end portion of the shaft, and a yoke which has a base end portion which is opened laterally and which constitutes a universal joint. A pair of restraining plate portions that constitute the base end portion, and these both restraining plate portions are arranged to be separated from each other by using the inner side surfaces as the restraining surfaces facing the respective outer flat surfaces. A connecting part that connects to each other on the side opposite to the opening, a concentric through hole or a screw hole formed in the both restraining plate parts, and a through hole formed in the tip part of the through hole through the through hole or the screw hole. In a connecting portion between a shaft having a retaining bolt for screwing a male screw portion into the screw hole or the nut and a yoke of a universal joint, the pair of retaining plate portions before the retaining bolt is tightened . The shape in the free state,
The cross-section circle whose convex surface is the inner surface of this pressing plate
By forming the arc shape, the distance between the restraining surfaces of the pair of restraining plate portions is narrow on the side close to the connecting portion, and wide on the opening side of the base end portion in which the through hole or screw hole is formed, Formed respectively, when tightening the holding bolt or the nut screwed with the holding bolt, the pair of outer flat surfaces and the respective holding surfaces start to come into contact with each other first on the side close to the connecting portion,
A joint portion between a shaft and a yoke of a universal joint, wherein a contact portion is moved to an opening side of the base end portion with progress of tightening work of the holding bolt. 2. A portion of the holding plate portion near the base end of the holding surface is a first cylindrical curved surface having a relatively small radius of curvature, and a portion from the middle portion of the holding surface toward the tip end has a relatively large radius of curvature. The connecting portion between the shaft and the yoke of the universal joint according to claim 1, wherein the second cylindrical curved surface has the second cylindrical curved surface and the two cylindrical curved surfaces are smoothly continuous with each other. 3. A yoke which has a shaft which rotates during use, a pair of outer flat surfaces formed on the outer peripheral surface of the distal end portion of the shaft, and a base end portion which is open laterally, and which constitutes a universal joint. A pair of restraining plate portions that constitute the base end portion, and these both restraining plate portions are arranged to be separated from each other by using the inner side surfaces as the restraining surfaces facing the respective outer flat surfaces. A connecting part that connects to each other on the side opposite to the opening, a concentric through hole or a screw hole formed in the both restraining plate parts, and a through hole formed in the tip part of the through hole through the through hole or the screw hole. In a connecting portion between a shaft having a retaining bolt for screwing a male screw portion into the screw hole or the nut and a yoke of a universal joint, the pair of retaining plate portions before the retaining bolt is tightened. The spacing between the restraining surfaces,
It is narrow on the side close to the connecting portion and wide on the opening side of the base end portion where the through hole or screw hole is formed, and at the same time, it is opposed to the outer flat surface of the shaft by a part of each restraining surface. A plurality of convex portions are formed on a portion of the holding surface at a plurality of positions spaced apart from each other in the width direction, and when the holding bolt or the nut screwed with the holding bolt is tightened, the pair of outer flat surfaces and the holding surfaces are held. The surface and the tip surface portion of the convex portion existing on the side closer to the connecting portion first starts to come into contact, and as the tightening work of the holding bolt progresses, the convex portion existing on the opening side of the base end portion The joint between the shaft and the yoke of the universal joint, characterized in that the contact area moves to the tip surface. 4. A thin portion is formed in a continuous portion between both widthwise end edges of the connecting portion and the base end edges of the respective restraining plate portions to reduce the rigidity of each continuous portion. The joint between the shaft and the universal joint yoke. 5. A yoke that rotates when used, a pair of outer flat surfaces formed on the outer peripheral surface of the distal end portion of the shaft, and a yoke that has a proximal end portion that is open to the side and that constitutes a universal joint, A pair of restraining plate portions that constitute the base end portion, and these both restraining plate portions are arranged to be separated from each other by using the inner side surfaces as the restraining surfaces facing the respective outer flat surfaces. A connecting part that connects to each other on the side opposite to the opening, a concentric through hole or a screw hole formed in the both restraining plate parts, and a through hole formed in the tip part of the through hole through the through hole or the screw hole. In a connecting portion between a shaft having a retaining bolt for screwing a male screw portion into the screw hole or the nut and a yoke of a universal joint, the pair of retaining plate portions before the retaining bolt is tightened. The spacing between the restraining surfaces,
The width is narrower on the side close to the connecting portion and wider on the opening side of the base end portion where the through hole or screw hole is formed, and both widthwise end edges of the connecting portion and the base ends of the both restraining plate portions are formed. A recess extending in the axial direction of the shaft is formed on the inner surface of the continuous portion with the edge, and the pair of outer flat surfaces and the respective restraining surfaces are provided when the restraining bolt or the nut screwed with the restraining bolt is tightened. The yoke of the shaft and the universal joint is characterized in that it starts to come into contact first on the side close to the connecting portion, and the contact portion moves to the opening side of the base end portion as the tightening work of the holding bolt progresses. The joint with.