JPH08338440A - Connection between shaft and yoke of universal joint - Google Patents

Abstract

PURPOSE: To make centering between a yoke and a shaft easily performable by the way of simple structure. CONSTITUTION: When a tap bolt 15 is clamped tight in order to press a shaft 7 down in space between a pair of keep plate parts 9a and 9b, an elastic arm part 39 is forcibly pressed inward the keep plate part 9b. In consequence, a second inclined edge 45 at a tip of this elastic arm part 39 pushes an end of the shaft 7 deep into a base end 8 of the yoke 3, whereby centering in this shaft 7 is carried out.

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 apparatus for imparting a steering angle to a front wheel of an automobile, the movement of a steering shaft that rotates with the operation of the steering wheel is passed through a cross shaft type universal joint 1 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 side (right side of FIG. 11)
The yoke 2 is fixed to the end of one shaft 6 such as a steering shaft in advance by welding or screwing, and the other yoke 3 (on the left side in FIG. 11) is connected to the end of the other shaft 7. To do. In order to perform such an assembling work, normally, 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. 11, one yoke 2 is welded and fixed to the end portion of one shaft 6, but 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.

As shown in FIG. 12, the base end portion 8 of the horizontal insertion type yoke 3 includes a pair of restraining plate portions 9a and 9b. These restraining plate portions 9 arranged apart from each other
The inner surfaces of a and 9b are holding surfaces 10 and 10 parallel to each other. And one side (left side of FIG. 12)
A screw hole 12 is provided by internally fitting and fixing a nut 11 at the opening side end of the restraining plate portion 9a. The other (Fig. 12
(To the right of) the screw hole 1 at the opening side end of the restraining plate portion 9b.
A through hole 13 concentric with the screw hole 12 and having a larger diameter than the screw hole 12 is formed. In addition, the screw hole 12 is, like the structural example described later,
In some cases, it may be directly formed on the pressing plate portion 9a.

On the other hand, in the yoke 3 constructed as described above,
The shaft 7 to which the tip portion is coupled has at least the tip portion in an oval shape as shown in FIG.
That is, a pair of outer flat surfaces 14, 14 which are parallel to each other are formed on the outer peripheral surface of the distal end portion of the shaft 7, and the outer flat surfaces 14, 14 and the restraining surfaces 10, 10 are brought into close contact with each other at the time of connection. The rotation of the shaft 7 with respect to the yoke 3 is prevented.

When the end portion of the shaft 7 having the above-described shape is connected and fixed to the base end portion 8 of the yoke 3 as described above, first, as shown by the solid line in FIG. The end portion is arranged on the opening side of the base end portion 8. Then, 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 holding bolts 15 (FIG. 14) are not inserted into the through holes 13.

If the end portion of the shaft 7 is inserted into the base end portion 8 of the yoke 3 as described above and the restraining surfaces 10 and 10 and the outer flat surfaces 14 and 14 (FIGS. 12 to 13) face each other. For example, the male screw portion formed at the tip of the holding bolt 15 inserted into the through hole 13 is screwed into the screw hole 12 and further tightened. Based on this tightening, the pair of holding surfaces 10, 10
The space between them is narrowed, and the restraining surfaces 10 and 10 and the outer flat surfaces 14 and 14 come into strong contact with each other, so that the distal end of the shaft 7 is fixedly coupled to the proximal end 8. In addition, a notch 35 is formed on one edge of the end of the shaft 7,
This prevents the shaft 7 from interfering with the rod portion of the holding bolt 15 and prevents the yoke 3 from slipping out in the axial direction of the shaft 7 even if the holding bolt 15 is loosened.

By the way, in order to smoothly transmit the rotational force between the pair of shafts 6 and 7 coupled through the universal joint 1, the center point O of the cross shaft 4 (FIG. 11). It is necessary to perform so-called centering, in which is located on the extension line of the central axes of both shafts 6 and 7. In the case of the universal joint 1 shown in FIG. 11, unless the positions of the other yoke 3 and the shaft 7 are regulated, the above alignment is not performed,
There is a risk that these two members 3, 7 will be joined together.

More specifically, the head 16 (FIG. 14) of the retaining bolt 15 is accompanied by the tightening of the retaining bolt 15.
Based on the frictional force that acts between the outer surface of the base end portion 8 and the base end portion 8, the other yoke 3 is displaced in the rotational direction about the holding bolt 15. If a general right-hand thread is formed on the male thread portion of the holding bolt 15, a tightening force of the holding bolt 15 causes a moment in the clockwise direction in FIG. As shown in the figure, the shaft 7 is inclined. As a result, as described above, the center point O of the cross shaft 4 deviates from the extension line of the center axis of the shaft 7, and the rotational force transmission between the pair of shafts 6, 7 is not smoothly performed.

For this reason, conventionally, the shapes and the shapes of the respective members 7 and 3 are arranged so that the above-mentioned centering is automatically performed in association with the work of connecting the end portion of the shaft 7 and the base end portion 8 of the yoke 3. A centering mechanism has been considered which regulates the dimensions and keeps the positional relationship between these members 7 and 3 constant during the coupling work.

FIGS. 15 to 16 show a first example of such an alignment mechanism described in US Pat. No. 5,090,833. A circular hole 17 having a size large enough to allow the holding bolt 15 to be inserted is provided at a position aligned with each other near both side openings of the base end portion 8 of the yoke 3.
A circular hole 18 having a diameter sufficiently larger than the circular hole 17 is formed concentrically with each other. The cylinder tube 19 is fixed to the outer end opening of the circular hole 18 among them. A pressing piece 20 is provided inside the cylinder tube 19, and the pressing piece 20 is pressed by a compression spring 21 in a direction projecting from the inner side surface of the base end portion 8. In addition, a screw hole 22 is formed in the bottom of the cylinder cylinder 19 for screwing the tip of the restraining bolt 15 into the screw hole 22. Further, a pair of inclined surfaces 23 and 24 having different inclination directions are formed on the inner end surface (right end surface in FIGS. 15 to 16) of the pressing piece 20 to form the inner end surface in a mountain shape. .

When the end portion of the shaft 7 and the base end portion 8 of the yoke 3 are connected, the end portion of the shaft 7 is placed inside the base end portion 8 as shown in FIG. Insert from the side opening side. At this time, the pressing piece 20 retreats into the cylinder cylinder 19 against the elastic force of the compression spring 21 based on the sliding contact between the outer peripheral surface of the end portion of the shaft 7 and the one inclined surface 23. Allow passage of the shaft 7. After passing, as shown in FIG. 16, the tip end of the pressing piece 20 projects from the inner side surface of the base end portion 8 based on the elasticity of the compression spring 21, and the end portion of the shaft 7 falls off the base end portion 8. Prevent from doing. Further, in this state, the other inclined surface 24 presses the outer peripheral surface of the end portion of the shaft 7 and pushes the end portion of the shaft 7 to the rear end of the base end portion 8. In this state, the above alignment is completed. Therefore, as shown in FIG. 16, if the holding bolt 15 is screwed into the screw hole 22 and further tightened, the base end portion 8 and the shaft 7 are joined together without rattling.

Next, FIGS. 17 to 19 show a second example of a conventionally known centering mechanism, which is the actual construction of Sho 55-38024.
It is shown in the publication. The recessed holes 2 are respectively provided at two positions separated from each other in the axial direction (left and right direction in FIG. 17) on a part of the outer flat surface 14 formed at the end of the shaft 7.
5 and 25 are formed, and a compression spring 26 is formed in each recess 25, 25.
18 and the steel ball 27, as shown in FIG.
Is inserted from the back side of. On the other hand, as shown in FIG. 19, a part of the restraining surface 10 provided on the base end portion 8 of the yoke 3 is
A groove 28 extending in the axial direction (front and back directions in FIG. 19) is formed.

When the end portion of the shaft 7 and the base end portion 8 of the yoke 3 are connected to each other, this end portion is inserted into the base end portion 8, and each of the steel balls 27 is moved by the elastic force of the compression spring 26. The groove 28 is elastically engaged. And each steel ball 2 like this
The above-mentioned centering is performed in a state in which 7 and the groove 28 are engaged.

Further, FIG. 20 shows a third example of a conventionally known centering mechanism, which is also shown in Japanese Utility Model Laid-Open No. 55-38024.
It is shown in the publication. Holding bolt 15
A sleeve 29 is externally fitted to the portion near the base end. The outer peripheral surface of the sleeve 29 is a conical convex surface 30 whose diameter increases toward the base end of the holding bolt 15. On the other hand, on the outer peripheral surface of the end portion of the shaft 7, the conical convex surface 30
A chamfered portion 31 inclined in the same direction as the conical convex surface 30 is formed at a position aligned with.

In order to connect the end portion of the shaft 7 to the base end portion 8 of the yoke 3, the male screw portion 32 formed on the tip end portion of the holding bolt 15 is formed in the holding plate portion 9a of the base end portion 8 and the screw hole 12 is formed. When it is screwed in, the conical convex surface 30 of the sleeve 29 is brought into sliding contact with the chamfered portion 31, and the end portion of the shaft 7 is pushed into the base end portion 8 for centering.

Further, FIG. 21 shows a fourth example of a conventionally known centering mechanism described in Japanese Utility Model Laid-Open No. 6-80029. A conical convex outer peripheral taper surface 33 is formed in the middle portion of the retaining bolt 15 so that the diameter increases as the distance from the male screw portion 32 formed at the tip of the retaining bolt 15 increases. Further, a retaining cylinder 34, which is deformable in the diametrical direction, is externally fitted to a portion of the retaining bolt 15 near the male screw portion 32. This holding cylinder 3
4 is strongly clamped axially between the outer peripheral taper surface 33 and the restraining surface 10 of the restraining plate portion 9a as the male screw portion 32 is screwed into the screw hole 12.

The end portion of the shaft 7 is inserted into the base end portion 8 of the yoke 3, and the male screw portion 32 of the holding bolt 15 is screwed into the screw hole 22 with the holding surface 10 and the outer flat surface 14 facing each other. When tightened, the retaining cylinder 34 fitted around the retaining bolt 15 is strongly clamped in the axial direction. Then, the holding cylinder 34 is deformed so as to bulge outward in the diametrical direction. As a result, a part of the restraining cylinder 34 pushes the end portion of the shaft 7 and pushes this end portion to the deep end of the base end portion 8 to align the shaft 7.

[0020]

However, in the case of the connecting portion between the conventional shaft and the yoke of the universal joint which is constructed and operates as described above, there are the following inconveniences. First, in the case of the structure of the first example shown in FIGS. 15 to 16, not only the structure is complicated and the manufacturing cost is high, but also because the cylinder tube 19 is installed, the universal joint becomes large and other parts are not used. The degree of freedom in design is reduced, for example, consideration must be given to avoid interference.

Further, in the case of the structure of the second example shown in FIGS. 17 to 19, it is inevitable that the processing and assembling of the constituent members are troublesome and the manufacturing cost is increased. Further, in the case of the structure of the third example shown in FIG. 20, it is necessary to process the chamfered portion 31 at the end of the shaft 7, which not only makes the processing operation troublesome, but also depends on the dimensions of the shaft 7. There may be a case where the chamfered portion 31 cannot be formed due to strength retention and the like.

Further, in the case of the structure of the fourth example shown in FIG. 21, the shaft 7 and the yoke 3 may not be surely aligned with each other depending on the tightening direction of the holding bolt 15. For example, when the holding bolt 15 is provided at the position shown in FIG. 14 with respect to the base end portion 8 and the male screw portion 32 (FIG. 21) of the holding bolt 15 is a general right-hand screw, The shaft 7 and the yoke 3 are easily displaced as shown in FIG. That is, at the end of tightening the holding bolt 15, the head portion 1 of the holding bolt 15 is
A large moment in the clockwise direction in FIG. 14 is applied to the base end 8 by the frictional force acting between the base 6 and the base end 8. The opposing force that prevents the central axis of the shaft 7 and the central axis of the yoke 3 from being displaced with respect to this large moment is generated when the holding cylinder 34 (FIG. 21) is deformed so as to expand outward in the diametrical direction. To do. However, since the holding cylinder 34 is made of a material that is easily deformed, the opposing force is small, and the effect of preventing the center axes of the both members 7 and 3 from being displaced is not always sufficient.

The base portion 8 is extended leftward in FIG.
If the span L ₁ which is the axial length between the pressing point by the presser cylinder 34 (FIG. 21) and the rear end edge of the base end portion 8 can be made sufficiently large, the presser bolt 15 can be tightened clockwise in FIG. It is possible to sufficiently prevent the central axes of the both members 7 and 3 from deviating from each other. However, such a solution is the above-mentioned base end portion 8
It is not always realistic because the size is increased. On the other hand, the span L ₂ which is the axial length between the pressing point of the pressing cylinder 34 and the front end edge of the base end portion 8 is larger than the span L ₁ .
Therefore, the male screw portion 32 of the retaining bolt 15 is left-handed, or the installation positions of the through hole 13 and the screw hole 12 are reversed (the retaining bolt 15 is inserted from the back side of FIG. 14).
Then, the function of preventing the central axes of the both members 7 and 3 from being displaced from each other is improved. However, it is not preferable to use a left-hand screw that is unfamiliar to the worker because the tightening workability is poor. Further, the assembling work of the universal joint for the steering device must be performed in a narrow engine room, and the holding bolt 1
In many cases, the insertion direction of 5 cannot always be freely selected. Therefore, it may not be possible to adopt a structure in which the holding bolt 15 is inserted from the rear surface side in FIG.

Other known structures for centering the yoke and the shaft are disclosed, for example, in US Pat. No. 5,090,833. However, in the case of the structure described in this specification, since a special shape and a large nut are used, the cost is high, and the radius of gyration of the universal joint is large, so that a large installation space is required. To do. The connecting portion between the shaft and the yoke of the universal joint according to the present invention is designed to eliminate any of these disadvantages.

[0025]

The joint between the shaft of the present invention and the yoke of the universal joint rotates at the same time as the joint between the shaft of the conventional fourth example and the yoke of the universal joint described above. The shaft, a pair of outer flat surfaces that are formed on the outer peripheral surface of the distal end portion of the shaft and are parallel to each other, and have a cross section U
The base end portion is formed in a letter shape and has a base end portion that is open to the side, and is arranged separately from the yoke that constitutes the universal joint. A pair of constraining plate portions, a screw hole provided at an opening side end portion of one restraining plate portion, and a screw hole concentric with the screw hole formed at the opening side end portion of the other restraining plate portion. A through hole having a diameter larger than that of the screw hole is provided, and a retaining bolt for screwing an externally threaded portion formed at the tip of the through hole into the screw hole while the through hole is inserted.

In particular, the connecting portion between the shaft and the yoke of the universal joint of the present invention includes a pair of through holes provided in a part of the other restraining plate portion and the restraining plate piece. The through hole is located in the vicinity of the through hole formed in the other restraining plate portion, and is located on both sides in the axial direction of the shaft with respect to the through hole, the outer surface of the other restraining plate portion. It is provided in a state of penetrating from to the inside surface. The restraining plate piece is made of an elastic plate and is supported by the outer surface of the other restraining plate portion, and a pair of elastic arms extending from the base portion and inserted through the through holes. And a section.

The portions of the elastic arms near the base end can be pressed inward by the head of the holding bolt.
Further, the distal end portion of each elastic arm portion abuts a portion of the outer peripheral surface of the distal end portion of the shaft with a portion near the opening of the proximal end portion so that the distal end portion faces the inner side of the proximal end portion. A pressing edge that can be pressed freely is formed.

[0028]

According to the connecting portion of the shaft of the present invention and the yoke of the universal joint configured as described above, the centering of the shaft can be surely performed without troublesome work despite the simple structure. I can do it. That is, by inserting the end of the shaft into the base end of the yoke and screwing the male screw portion of the restraint bolt into the screw hole with the outer flat surface and the restraining surface facing each other, and further tightening, The elastic arms having a pair of heads are pushed inward of the pair of through holes.

As a result, the pressing edge formed on the tip of each of these elastic arms abuts the edge of the shaft near the opening on the outer peripheral surface of the tip, and the tip of the outer edge is abutted. The part is pushed toward the back of the base end. As a result, the tip portion of the shaft is pushed into the inner part of the base end portion of the yoke at two axially separated positions, and the shaft and the yoke are aligned.

[0030]

1 to 8 show a first embodiment of the present invention. The cross-sectional shape of the tip portion of the shaft 7 that rotates during use is an oval shape as shown in FIG. 13 or a bread shape, and a pair of outer flat surfaces 14 and 14 parallel to each other are formed on the outer peripheral surface of the tip portion. Is forming. When adopting an oval cross-sectional shape, this one end edge portion (upper edge portion of FIGS. 3 to 4) prevents interference with the holding bolt 15 and
A cutout 3 for preventing the yoke 3 from slipping out in the axial direction of the shaft 7 even if the holding bolt 15 is loosened.
5 is formed.

On the other hand, the universal joint 1 as shown in FIG.
The yoke 3 that constitutes the
It has a base end portion 8 which is open above 3, 4, 7 and in front of FIG. The base ends 8 are spaced apart from each other.
It has a pair of restraining plate portions 9a and 9b. The inner side surfaces of the restraining plate portions 9a and 9b are restraining surfaces 10a and 10b facing the outer flat surfaces 14 and 14, respectively. Further, one side (back side in FIG. 1, upper side in FIG. 2, left side in FIGS. 3 and 7) of the restraining plate portion 9
The nut 11 is fitted and fixed to the opening side end of the screw hole 1
2 on the other side (front side of FIG. 1, lower side of FIG. 2, right side of FIGS. 3 and 7)
Through holes 13 are formed at the opening-side ends of the holding plate portions 9b. The through hole 13 is concentric with the screw hole 12 and has a larger diameter than the screw hole 12. Holding bolt 15
In the state where the through hole 13 is inserted, the male screw portion 32 formed at the tip end portion is screwed into the screw hole 12.

The above structure is the same as the conventional structure described above. Particularly, in the connecting portion of the shaft of the present invention and the yoke of the universal joint, a pair of through holes 36, 36 are provided in a part of the other restraining plate portion 9b. The pair of through holes 36, 36 are provided in the vicinity of the through hole 13 formed in the other restraining plate portion 9b, and on both axial side portions of the through hole 13. Both of these through holes 36, 36
Is provided so as to penetrate from the outer side surface to the inner side surface of the other restraining plate portion 9b. Further, in the state in which the tip end portion of the shaft 7 is pushed deep into the base end portion 8, the inner openings of the both through holes 36, 36 are, as shown in FIG. (When the notch 35 is formed, it is aligned with the edge of the notch 35).

A pressing plate piece 37 is attached to the outer side surface of the other pressing plate portion 9b. The pressing plate piece 37 made of an elastic plate such as a spring steel plate is a ring-shaped base portion 3.
8 and a pair of elastic arm portions 39, 39 extending from the outer peripheral edge of the base portion 38. Of these, the base portion 38 has an inner diameter through which the holding bolt 15 can be inserted. A cylindrical portion 40 is formed on the inner peripheral edge of the base portion 38. The outer diameter of the cylindrical portion 40 in the free state is equal to that of the other restraining plate portion 9 described above.
It is equal to or slightly larger than the inner diameter of the through hole 13 of b. Such a base portion 38 has a through hole 13 for the cylindrical portion 40.
It is supported on the outer side surface of the restraining plate portion 9b by being fitted inside. The pair of elastic arm portions 39, 39 extending from the base portion 38 in the state where the base portion 38 is supported by the restraining plate portion 9b in this way are provided with the through holes 36, 36, respectively.
The distal end portions are made to penetrate from the outer side surface side to the inner side surface side and protrude from the inner side surface of the other restraining plate portion 9b.

The portions of the elastic arms 39, 39 close to the base end are inward (see FIG. 1) by the head 16 of the holding bolt 15.
2), the upper side of FIG. 2, and the left side of FIG. 7). That is, the connecting convex portion 41 is formed on the outer peripheral edge of the base portion 38.
The folded-back portions 42, 42 are formed so as to project diametrically outward from the outer peripheral edge and are formed at the base end portions of the elastic arm portions 39, 39 from the both end edges of the connecting convex portion 41. It is extended. Before the tightening of the restraining bolt 15, the folded-back portions 42, 42 project from the outer side surface of the other restraining plate portion 9b as shown in FIG. Then, one surface (the upper surface of FIG. 2, the left side surface of FIGS. 7 to 8) of the seat plate 43 that is externally fitted to the holding bolt 15 faces the folded portions 42, 42. Therefore, when the restraining bolt 15 is tightened, the head portion 16 presses the folded-back portions 42, 42 toward the restraining plate portion 9b via the seat plate 43.

Furthermore, at the tip of each of the elastic arms 39, 39, first and second slanted edges 44, 45 whose slanting directions are opposite to each other, and these slanted edges 44, 45 are continuous with each other. And straight edges 46 to be formed respectively. Of these, the first straight edge 44 existing on the opening side of the base end portion 8 is
The elastic arm portion 3 is located beyond the second inclined edge 45 existing on the back side.
It is formed up to the tip side of 9. Therefore, the straight edge 4
6 faces the inner side of the base end portion 8. Each of these edges 44-
Of the 46, the second inclined edge 45 corresponds to a pressing edge that abuts the opening-side edge portion of the base end portion 8 at a part of the outer peripheral surface of the tip end portion of the shaft 7. That is, in a state where the second inclined edge 45 and the edge of the shaft 7 near the opening are abutted,
When the elastic arms 39, 39 are pressed inward, the distal end of the shaft 7 is moved to the proximal end 8 based on the engagement between the second inclined edge 45 and the edge of the shaft 7 near the opening. Is pressed toward the back of the.

According to the connecting portion between the shaft of the present invention and the yoke of the universal joint configured as described above, the yoke 3 and the shaft 7 can be connected to each other without any troublesome work despite the simple structure. The two members 3 and 7 can be joined to each other and the centers of the members 3 and 7 can be reliably aligned. In order to connect these two members 3 and 7, first, the front end portion of the shaft 7 is fixed to the base end portion 8 of the yoke 3 before inserting the holding bolts 15 into the base end portion 8 of the yoke 3 as shown in FIG. As shown, the base end 8 is inserted from the opening side. With this insertion work, each of the elastic arm portions 3 is
As shown by the chain line in FIG. 6, the elastic members 9 and 39 retreat to the outside of the restraining plate 9b while elastically deforming, and these elastic arms 39 and 39 are retracted.
Allow the shaft 7 to pass through the part. After the passage, the elastic arms 39, 39 are restored, and the linear edge 46 and the edge of the shaft 7 near the opening are engaged with each other as shown in FIG. As a result, this shaft 7 is
There is no need to carelessly get out of.

In this way, the tip end of the shaft 7 is inserted into the base end 8 of the yoke 3, and the outer flat surfaces 14 and 1 of the shaft 7 are inserted.
4 and the holding surfaces 10a, 10b of the base end portion 8 are opposed to each other, then the holding bolt 15 is inserted into the through hole 13 from the outer surface side of the other holding plate portion 9b. Then, the male screw portion 32 of the holding bolt 15 is screwed into the screw hole 12 and further tightened. By this tightening work, the head portion 16 of the holding bolt 15 presses the folded-back portions 42, 42 toward the outer side surface of the holding plate portion 9b via the seat plate 43. As a result, the pair of elastic arms 39, 39 provided at the respective base end portions of the folded-back portions 42, 42 are pushed into the pair of through holes 36, 36.

The second slanted edge 45, which is a pressing edge, is formed at the tip of each of the elastic arms 39, 39.
Based on the abutting of the outer peripheral surface of the tip end portion of the shaft 7 with the edge of the base end portion 8 near the opening, the tip end portion is pressed toward the back of the base end portion 8. As a result, this shaft 7
The distal ends of the shafts 3 are pushed into the inner part of the base end part 8 of the yoke 3 at two axially separated positions, and the shaft 7 and the yoke 3 are aligned with each other. In the illustrated embodiment, the elastic arms 39, 39 are inclined with respect to the holding bolt 15. Therefore, this restraint bolt 1
When tightening 5, the elastic arm portions 39, 39 do not have excessive tension force. Therefore, the holding bolt 15
Can be securely tightened.

The shape of the tip edge of each elastic arm portion 39, 39 is not limited to the shape shown in FIGS. 3, 4, 5 and 7, but may be a mountain shape as shown in FIG. It is also possible to have a semicircular shape as shown in FIG. Further, if the inclined surface 47 is formed on the shaft 7 side as in the second embodiment shown in FIG. 10,
The tip edge may be inclined only in one direction, or may be a straight edge that is not inclined (not shown). Since the inclined surface 47 can be made smaller than the chamfered portion 31 having the conventional structure shown in FIG. Even when the inclined surface 47 is formed, the work of inserting the shaft 7 into the base end portion 8 can be facilitated by inclining the tip ends of the elastic arm portions 39, 39 as shown in FIG. I can do it. However, if the cross-sectional shape of the shaft 7 is oval or bread-shaped, the shaft 7 is automatically inserted into the base end portion 8 (the shaft 7 even if the tip edge is a straight edge).
The elastic arm portions 39, 39 can be inserted without being deformed outward by a force other than the insertion.

[0040]

The joint between the shaft and the yoke of the universal joint according to the present invention is constructed and operates as described above. However, despite the simple construction, the centering of the shaft can be performed without troublesome work. Therefore, it is possible to provide a universal joint that is easy to assemble at low cost. In particular, since a reliable centering can be performed regardless of the screwing direction of the tightening bolt, the assembling direction, and the shape and size of the yoke, it is possible to realize a universal joint that is small and lightweight and has good assembling workability.

[Brief description of drawings]

FIG. 1 is a side view of a yoke to which a pressing plate piece is attached, showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an enlarged sectional view taken along line C-C of FIG.

FIG. 5 is a view corresponding to part D in FIG. 4, showing a state in which the shaft is being inserted.

6 is a view seen from the lower side of FIG. 5, showing a state in which the elastic arm portion is deformed with the insertion of the shaft.

FIG. 7 is a view similar to FIG. 4, showing a state in which tightening of the holding bolts is started after the shaft is inserted.

8 is a view showing a state in which the elastic arm portion is pressed by a seat plate, as seen from the lower side of FIG. 7.

9A and 9B are views showing another two examples of the tip edge shape of the elastic arm portion.

FIG. 10 is a sectional view showing a second embodiment of the present invention.

FIG. 11 is a side view showing a state where the end portion of the shaft and the base end portion of the yoke are joined together.

12 is a sectional view taken along line EE of FIG.

FIG. 13 is a sectional view taken along the line FF.

FIG. 14 is a side view showing a state where the central axis of the shaft and the central axis of the yoke are displaced from each other.

FIG. 15 is a sectional view showing a first example of a conventional structure in a state where a shaft is being assembled.

FIG. 16 is a sectional view similarly showing a state after completion of assembly.

FIG. 17 is a side view of a shaft end portion showing a second example of the conventional structure.

18 is a sectional view taken along line GG of FIG.

FIG. 19 is a cross-sectional view showing a state in which a shaft and a base end portion are coupled to each other.

FIG. 20 is a sectional view showing a third example of the conventional structure.

FIG. 21 is a sectional view showing the fourth example.

[Explanation of symbols]

 1 Universal Joint 2, 3 Yoke 4 Cross Shaft 5 Bearing Cup 6, 7 Shaft 8 Base Ends 9a, 9b Suppression Plates 10, 10a, 10b Suppression Surface 11 Nuts 12 Screw Holes 13 Outer Plane 15 Storing Bolts 16 Heads Part 17, 18 Circular hole 19 Cylinder cylinder 20 Holding piece 21 Compression spring 22 Screw hole 23, 24 Inclined surface 25 Recessed hole 26 Compression spring 27 Steel ball 28 Recessed groove 29 Sleeve 30 Conical convex surface 31 Chamfered part 32 Male screw part 33 Outer taper Surface 34 Suppression Tube 35 Notch 36 Through Hole 37 Suppression Plate Piece 38 Base 39 Elastic Arm 40 Cylindrical Section 41 Connecting Convex Section 42 Folding Back 43 Seat Plate 44 First Inclined Edge 45 Second Inclined Edge 46 Straight Edge 47 Inclination surface

Claims (1)

[Claims] 1. A shaft which rotates during use, a pair of outer flat surfaces which are formed on an outer peripheral surface of a distal end portion of the shaft and which are parallel to each other, and a proximal end portion which is substantially U-shaped in cross section and is open to the side. A pair of restraint plate portions constituting the base end portion, which are arranged separately from each other, and whose inner side surfaces are restraining surfaces facing the respective outer flat surfaces,
A screw hole provided at the opening-side end of one restraining plate portion, and a through hole formed at the opening-side end of the other restraining plate portion, which is concentric with the screw hole and has a larger diameter than this screw hole. , In the connecting portion between the shaft and the yoke of the universal joint, which is provided with a retaining bolt for screwing the male screw portion formed at the distal end portion of the through hole into the screw hole, the other retaining member A part of the plate portion is located in the vicinity of the through hole, and is provided on both axial side portions of the shaft with respect to the through hole in a state of penetrating from the outer surface to the inner surface of the other restraining plate portion. A pair of through-holes and a retaining plate piece made of an elastic plate, the retaining plate piece being supported by the outer surface of the other retaining plate portion, and each extending from this base portion A pair of elastic arms that are inserted through the through-holes; It can be pressed inward by the head of the bolt, and the distal end of each elastic arm is abutted with a portion of the outer peripheral surface of the distal end of the shaft at a portion near the opening of the proximal end, and the distal end A coupling portion between a shaft and a yoke of a universal joint, characterized in that a pressing edge is formed so that the portion can be pressed toward the back of the base end portion.