JPH06198521A - Method and device for automatically fitting retaining ring - Google Patents

Abstract

PURPOSE:To automatically fit a retaining ring by engaging the retaining ring contracted in the diameter with the tip of a retaining ring fitting rod and after inserting the rod into a tubular body provided on the inner wall with an fitting goove, disengaging the retaining ring from the tip by the action of a depressing member to fit the retaining ring in the fitting groove. CONSTITUTION:When a retaining ring 2 is attached to an annular grove 4a inside a tubular body 1, the retaining ring 2 is contracted in the diameter previously by a separate device. Short pins 8a, 8b on the tip of a fitting rod 5 are engaged with small holes 9a, 9b in both ends of the retaining ring 2 under the such contracted state. Next, the tubular body 1 is fitted in a jig 31 having a protrusive section. After a rod 5 is moved above the tubular body 1, the rod 5 is lowered by an operation of a cylinder so that the tip of the rod advances in the tubular body 1 until it reaches somewhat the upper side of the annular groove 4a. Next, a U-shaped depressing member 15 disposed sideways is advanced between both upper and lower collars 10, 12 of the rod 5 and the lower collar 10 is depressed by the action of the cylinder 16 to disengage the retaining ring 2 from the short pins 8a, 8b so that the retaining ring is fitted in the groove 4a by a spring force caused by the contraction thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a partition plate in a cylindrical body or inserts a bearing or other parts into a predetermined portion of the cylinder in order to prevent the inserted parts from being positioned and removed. The present invention relates to a method and a device for automatically fitting a snap ring, which is fitted into an annular groove formed at a predetermined position on a wall surface of a cylinder, or a retaining ring, which is also called a C ring due to its shape, into the annular groove.

[0002]

2. Description of the Related Art This retaining ring has been widely used in the past because various parts can be easily fixed in a cylinder as described above. In order to fit this retaining ring into the annular groove on the inner surface of the cylinder, a worker conventionally inserts pins that are erected at both ends of a special tool such as scissors into small holes formed at both ends of the retaining ring. Grasp the tool firmly to compress the retaining ring, shrink its outer shape in a plane, and then insert it into the cylinder as it is,
The tool is spread at a predetermined groove position and the retaining ring is fitted into the annular groove.

However, the work of fitting the retaining ring requires a great deal of skill and labor, and it is difficult to fit the retaining ring in the groove accurately, and this work becomes more difficult when the tubular body is small, and thus it becomes difficult. Since it is not inserted in the above, there is a problem that the inserted parts may fall off later.

Further, when this fitting work is automatically performed, a jig having a tapered inner diameter is used as a guide for inserting the retaining ring, and the outer diameter of the retaining ring is pushed by pushing the rod of the press machine from above. While compressing so as to be the same as the above, it is inserted into the cylinder and fitted into the groove. However, according to this method, the retaining ring can be fitted only in the foremost groove from one direction of the mouth of the tubular body because of the shape of the retaining ring and the degree of compression thereof. It is not possible to insert a snap ring into the groove at the back of the box.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a retaining ring can be accurately and easily automatically fitted into an arbitrary annular groove in a cylinder having a plurality of annular grooves. The present invention provides a method and a device capable of mounting the above retaining ring.

[0006]

SUMMARY OF THE INVENTION That is, according to the present invention, the tip of a snap ring fitting rod that can be inserted and removed by sliding closely in a cylinder having a plurality of annular grooves into which snap rings are to be fitted is sectioned. A plurality of long grooves are formed in the outer periphery of the rod so as to form a gear shape in the length direction of the rod, and one end surface of the rod tip end surface that forms the gear-shaped mountain portion is opened at both ends of the retaining ring. Two short pins that fit into the small holes and that can hold the retaining ring in a planar state in a protruding manner are provided, and a lower collar is slidably attached to the outer periphery of the rod tip end portion. A plurality of push-out pieces, which are slidably fitted into the long groove of the rod and are slightly shorter than the long groove, are protruded and fixed downward on the inner periphery of the lower collar, and the same shape as the lower collar is formed on the outer periphery above the long groove of the rod. The upper brim is fixed, and two bolts are inserted into the upper brim, and the lower end of the bolt is the lower brim. A coil spring is wound around the bolt shaft of the upper portion of the upper collar, and the lower collar is urged so as to pull it up in the direction of the upper collar. First, a cylinder is formed by a jig having a convex cross-section, which is formed integrally with an insertion portion that is fitted and has a height matching the lower edge of a predetermined annular groove into which the snap ring is to be inserted first in the inner part of the cylinder. The body is fixed, and then the rod is moved into and out of the cylinder with the snap ring surface-compressed and attached to the short pin at the rod tip, and the rod is positioned slightly above the predetermined annular groove. Stop, and then a vertically-moving and horizontally-movable push-down member arranged in a lateral direction of the rod is inserted into the upper side of the lower brim, and the lower brim is pushed by the pushing member. The lower end of the extruded piece integrated with this is pushed out by pushing the retaining ring It is obtained so as to fit the wheel predetermined annular groove. Embodiments of the present invention will be described below with reference to the drawings.

[0007]

【Example】

Example-1 FIG. 1 is an explanatory view showing a device for fitting a retaining ring 2 into an annular groove when mounting one bearing 3 in a cylinder 1.
The bearing 3 has two grooves 4a and 4b on the inner surface of the cylindrical body 11 which are upper and lower.
It will be fixed between the retaining rings 2 which are respectively fitted in.

In the figure, reference numeral 5 denotes a piston rod for fitting a retaining ring driven by a cylinder 6, the outer diameter of the rod 5 being equal to the inner diameter of the tubular body 1, and the rod 5 can be slid in and out of the tubular body 1 for insertion and removal. It is like this. A plurality of long grooves 6 are formed in the outer periphery of the rod 5 at equal intervals in parallel with the longitudinal direction of the rod 5 so that the distal end portion of the rod 5 has a gear shape. The retaining ring 2 is provided on both end portions of the retaining ring 2 so that the retaining ring 2 can be held on one end face forming the ridge portion 7 in a state in which the retaining ring 2 is compressed in such a manner that the cylindrical body 1 can be loosely inserted. Two short pins 8 that fit into the small holes 9a and 9b
a and 8b are projected.

Reference numeral 10 denotes a donut-shaped lower collar which is slidable with the tip end of the rod 5 fitted therein, and is slidable by being fitted in the long groove 6 of the rod 5 on the inner periphery of the collar 10. A plurality of extruding pieces 11 are attached and fixed so as to project downward. Reference numeral 12 denotes an upper brim having the same shape as the lower brim 10 fixed to an upper portion of the long groove 6 of the rod 5, and a bolt 13 is inserted at an opposing position across the rod 5 of the upper brim 12 and its tip is A coil spring 14 is screwed on the upper surface of the lower collar 10, and a coil spring 14 is wound around the shaft of the bolt 13 on the upper side of the upper collar 12 so that the lower collar 10 is always pulled up. However, the extruded piece 11 is slightly shorter in length than the lower end of the long groove 6 that fits with the extruded piece 11, and the lower brim 10
The lower end of the pushing piece 11 is slightly retracted inward from the lower end of the long groove 6 at the pulling end of the
2 and 10 are regulated so that they are not in close contact with each other and are slightly spaced.

Reference numeral 15 denotes a pushing member having a substantially U-shape in a plane which is arranged laterally in the traveling direction of the rod 5. The pushing member 15 is attached to the rod head end of the upward cylinder 16 and moves up and down and is arranged downward. Sideways installed cylinder (not shown)
When the rod 5 comes down to a predetermined position while the retaining ring 2 is engaged with the short pins 8a and 8b at the lower end thereof in a compressed state, the member 15 moves the upper and lower flanges 12 and 12,
10 and then the cylinder 16 is driven to lower the member 15 slightly to push down the lower collar 10 against the spring 14, whereby the lower end of the push-out piece 11 is pushed to the upper surface of the retaining ring 2. The retaining ring 2 is pressed down to separate the retaining ring 2 from the short pins 8a, 8b.

As shown in FIG. 3, the retaining ring 2 is attached to the short pins 8a, 8b at the tip of the rod 5 in the following manner. That is, reference numeral 17 denotes a guide table in which a shaft 22 described later has a fitting guide groove 18 formed therein.
A slide plate 19 that slides forward and backward while sliding along the guide groove 18 is disposed on the upper surface of the slide plate 7, and the retaining ring 2 has a circular recess on the upper surface of the front end of the slide plate 19 that can be accommodated in the compressed state. A recess 20 is formed. A push-up piece 21 is provided on the inner bottom of the recess 20, and a shaft 22 penetrating the bottom of the recess 20 is vertically fixed to the center of the lower surface of the push-up piece 21.
The portion of the shaft 22 outside the bottom surface of the recess is the guide groove 18
A compression coil spring 23 is wound around the inside of the recessed portion 20 so that the push-up piece 21 is urged so as to come into pressure contact with the inner bottom surface of the recess 20.

Reference numeral 24 is a guide block located above the slide plate 19 and in contact with the slide plate 19 and above the rear end of the guide groove 18 of the guide table 17. A guide hole 25 having a downward tapered shape is opened, and the upper surface of the hole 25 has a diameter that allows the snap ring 2 to be loosely fitted, and the lower surface has a diameter that matches the concave recess 20 described above. Therefore, if the retaining ring 2 horizontally inserted into the upper portion of the hole 25 is forcibly pushed in, the retaining ring 2 is gradually compressed in a plane. Reference numeral 26 designates a downward tapered taper-shaped guide key provided on the inner surface of the guide hole 25 so that the gap between the two ends of the retaining ring 2 is formed in the key 2
By inserting the snap ring 2 into the guide hole 25 in accordance with the position 6, the snap ring 2 is regulated so as not to rotate when the snap ring 2 is compressed in the guide hole 25.

Reference numerals 27 and 28 denote first and second pushing rods arranged above the guide block 24, both of which are attached to the same press machine (not shown), and the first rod 27 has a tapered guide hole. The second rod 28 has the same diameter as the lower surface of the guide hole 25.

When the slide plate 19 is retracted so that the recess 20 is aligned with the lower surface of the guide hole 25 of the guide block 24, first, the retaining ring 2 is attached to the guide key 25 and the guide ring 26 is attached to the upper portion of the guide hole 25. The gaps are aligned and inserted horizontally (see FIG. 3A). Then, when the press machine operates and the first pushing rod 27 descends, enters the guide hole 25 and pushes the retaining ring 2 to the intermediate position of the hole 25 while planarly compressing it, the rod 27 rises. . Next, the second pushing rod 28 is moved to the guide hole 25 by the switching operation.
After moving horizontally upward, the second rod 28 deeply enters into the guide hole 25 by the pressing machine, further compresses the retaining ring 2 to a smaller degree, and finally the retaining ring 2 slides on the slide plate 19.
The second rod 28 rises when it is pushed into the recess 20 (see FIG. 3B).

When the snap ring 2 is fitted in the concave recess 20, the slide plate 19 advances, and above the position of the concave recess 20 at the forward end, the snap ring fitting rod having the short pins 8a, 8b at the lower end is inserted. 5 is waiting. Reference numeral 29 denotes a push-up cylinder disposed below the position of the recess 20 at the forward end, and when the slide plate 19 stops at the forward end, the upper snap ring fitting rod 5 descends to cause the short pins 8a, 8b at the tip end. Is fitted into the small holes 9a and 9b of both ends of the retaining ring 2 in the recess 20, and at the same time, the rod 30 of the push-up cylinder 29 is lifted to raise the recess 2
The shaft 22 hanging downwards is pushed up against the spring 23, and the snap ring 2 is securely attached to the short pins 8a and 8b at the tip of the rod 5.

In this way, when the retaining ring 2 is attached to the tip of the retaining ring fitting rod 5, the retaining ring 2 does not easily come off due to the spring force due to its compression, and the rod 5 rises as it is. To the cylinder 1 at a predetermined position, and the push-up cylinder 29 and the slide plate 19 respectively return to prepare for the next attachment of the retaining ring 2 to the tip of the rod 5.

Then, a method for fitting the retaining ring 2 engaged with the lower end of the retaining ring fitting rod 5 into the annular grooves 4a and 4b in the simplified body 1 will be described with reference to FIG. Reference numeral 31 is a jig having a convex cross section for fixing the tubular body 1 into which the snap ring 2 is to be fitted. The insertion portion 31a of the jig to be inserted into the tubular body 1 is closely fitted to the inner diameter of the tubular body 1. , Its upper end has a height matching the lower edge of the lower annular groove 4a, and the retaining ring 2 is first fitted into the lower groove 4a by using this jig.

That is, the retaining ring fitting rod 5, which is engaged in a compressed state with the retaining ring 2 at the lower end as described above, moves above the cylindrical body 1 fixed to the insertion portion 31a of the jig 31. Then, the tip of the rod 5 enters the cylinder 1 as it is and descends (Fig. 4 (a)), and stops slightly above the lower full 4a (Fig. 4 (b)). When the tip of the rod 5 passes through the upper groove 4b, the retaining ring 2 is held in a compressed state, so there is no risk that the retaining ring 2 will fit into the upper groove 4b. Next, the U-shaped push-down member 15 arranged laterally advances to move the rod 5
Between the upper and lower collars 10 and 12, and the pushing-down member 15 pushes down the lower collar 10 against the spring 14 by the cylinder 16. As a result, the lower end of the extruding piece 11 integrated with the lower collar 10 slides on the inner surface of the tubular body 1 to extrude the retaining ring 2 from the lower end of the rod 5, and the short pin 8a,
8b is disengaged, and the retaining ring 2 is fitted into the lower groove 4a all at once at the position of the lower groove 4a by the spring force due to the compression thereof (FIG. 4C).

When the retaining ring 2 is fitted in this way, the push-down member 15 is raised and retracted, and the upper and lower flanges 12, 10 are joined together.
The rod 5 rises as it leaves the space. Then, next, when the bearing 3 is inserted and placed on the upper side of the retaining ring 2 fitted in the lower groove 4a, the next retaining ring 2 is attached to the tip of the retaining ring fitting rod 5 again in the same manner as described above, and the lower end of the rod 5 is engaged. When the retaining ring 2 is inserted into the upper groove 4b by pushing the retaining ring 2 into the cylindrical body 1 and pushing out the retaining ring 2 by the push-down member 15, the bearing 3 is securely held and fixed by the retaining ring 2 inserted in the upper and lower annular grooves 4a and 4b. Of.

Embodiment-2 By the way, when two bearings 3 are mounted in the cylindrical body 1, four retaining rings 2 are required. In this case, first, the retaining rings 2 are retained in the inner annular grooves 4a, 4b. After inserting the wheel 2,
It is necessary to insert the bearings 3 into the outer sides thereof, respectively, and then to fix the retaining rings 2 into the outer annular rings 4b and 4d.

In this case, the first retaining ring 2 uses the convex jig 31 described in the first embodiment and one inner annular groove 4 is formed.
It can be securely fitted to a, but the second retaining ring 2
When the one is fitted into the other inner annular groove 4c, the retaining ring 2 fitted previously interferes with the insertion portion 31 of the convex jig 31.
It is impossible to insert a to the position of the annular groove 4c.

Therefore, in this case, another jig is used. That is, reference numeral 32 in FIG. 5 indicates a split chuck (collet chuck) type jig that can be inserted into the cylindrical body 1 and can be pushed open. Corresponding to this, a taper is formed at the center of the tip end surface of the snap ring fitting rod 5. -Shaped projecting portion 33 is screwed, and the projecting portion 33 projects into the tip portion of the chuck type jig 32 to push the jig 32 open, and the tip peripheral surface 32a of the jig 32 is a cylinder. It is pressed against the inner surface of the body 1. The tip surface of the jig 32 is slightly inclined toward the center and has a substantially mortar shape, and is flat when the tip portion of the jig 32 is pushed open.

However, if the first retaining ring 2 is fitted into the inner annular groove 4a of the tubular body 1 as in the first embodiment, the tubular body 1 is turned upside down and the open side is raised. Then, the cylindrical body 1 is fixed so that the chuck type jig 32, which is vertically fixed on the table, is inserted. At this time, the upper end of the jig 32 has a height that matches the lower edge of the other inner groove 4c into which the second retaining ring is to be fitted (FIG. 6A).

Then, similarly to the above, the rod 5 having the retaining ring 2 attached to the lower end thereof descends, and the tapered protrusion 3 at the lower end.
When 3 is inserted into the upper end of the chuck type jig 32, the upper side of the jig 32 is pushed open and its peripheral surface 32a is pressed against the inner surface of the cylindrical body 1 (FIG. 6B). At this time, the lowering of the rod 5 is stopped in this state, and the retaining ring 2 is located slightly above the groove 4c. Next, in the same manner as described above, the push-down member 15 enters between the upper and lower brims 12 and 10, and then the lower brim 10 is pushed down to release the retaining ring 2 by the lower end of the pushing piece 11 so as to remove the retaining ring 2. 2 is inserted into the groove 4c at once (FIG. 6C).

Then, this is completed, and the rod 5 becomes the cylindrical body 1.
After coming out of the rod 5, the first bearing 3 is inserted onto the retaining ring 2 fitted in the groove 4c, and the protruding portion 33 at the lower end of the rod 5 is inserted.
And the third retaining ring 2 is fitted into the outer (upper) annular groove 4d in the same manner as in the first embodiment.

Next, the cylindrical body 1 is reversed again and returned to the original state, and the second bearing 3 is inserted above the first retaining ring 2 fitted in the groove 4c, and the fourth bearing 3 is inserted. The retaining ring 2 is fitted in the groove 4b.

[0027]

The method of fitting the retaining ring into the cylinder according to the present invention is as described above, and the cylinder among the annular grooves having a plurality of steps, which has been very difficult mechanically as well as manual work in the related art, is used. The retaining ring can be securely inserted into the annular groove at the back of the body, and there is no concern that the bearings, partition plates, etc. that should be supported and fixed in the cylinder will fall out, and the jigs will be used properly. As a result, even if the retaining ring is already fitted, it is possible to fit another retaining ring from the opposite direction of the tubular body.
It has an excellent effect that two parts such as bearings can be attached to the inner part of the cylinder at a predetermined interval.

[Brief description of drawings]

FIG. 1 is an overall explanatory view showing an embodiment of an apparatus used in a method for automatically fitting a retaining ring of the present invention.

FIG. 2 is a perspective view showing a main part of an apparatus used in the method for automatically fitting a retaining ring according to the present invention.

FIG. 3 is an explanatory view showing a method of engaging the retaining ring with the end of the retaining ring fitting rod, (a) an action explanatory diagram of planarly compressing the retaining ring in the guide block, and (b) shows FIG. 7 is an operation explanatory view showing a manner of engaging the retaining ring, which is pressed into the recess of the slide plate and compressed, with the tip of the fitting rod.

FIG. 4 is an operation explanatory view according to the method of the present invention in which a retaining ring, which is engaged in a compressed state with the end of the retaining ring fitting rod, is fitted into a second-stage groove of the annular groove having a plurality of stages in the cylinder. (A) shows the state before inserting the retaining ring into the cylinder, (b) shows the state during insertion, and (c) shows the state of fitting into the predetermined annular groove.

FIG. 5 is a perspective view showing a jig and a fitting rod tip portion used in another embodiment of the method of the present invention.

FIG. 6 is a view showing a state in which a jig and a snap ring fitting rod shown in FIG. 5 are used and one snap ring is already fitted into the inner annular groove in the cylinder by the device shown in FIG. It is explanatory drawing which shows the method of inserting another retaining ring into another inner ring groove from a mouth, (a) before insertion in a cylinder, (b) during insertion,
(C) shows a state of fitting into a predetermined annular groove, and (D) shows a state of inserting a bearing onto the retaining ring and then inserting a third retaining ring.

[Explanation of symbols]

 1-Cylinder body 2-Retaining ring 3-Bearing 4-Multi-step annular groove 5-Retaining ring fitting rod 6-Long groove 7-Mounting part 8-Short pin 9-Small hole 10-Bran 11-Extrusion piece 12-Up Collar 13-Bolt l4-Coil spring 15-Pressing member 16-Cylinder 17-Guide table 18-Guide groove 19-Slide plate 20-Recess 21-Pushing piece 22-Shaft 23-Coil spring 24-Guide block 25- Guide hole 26-Guide key 27-First push rod 28-Second push rod 29-Push-up cylinder 30-Rod 31-Convex jig 32-Split chuck jig 33-Tapered protrusion

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[Procedure amendment]

[Submission date] July 14, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 3]

[Figure 5]

[Figure 1]

[Fig. 2]

[Figure 4]

[Figure 6]

Claims (5)

[Claims] 1. A plurality of tip end portions of a snap ring fitting rod that is slidable in a cylinder body having a plurality of annular grooves into which snap rings are to be fitted and which can be inserted / removed so as to have a gear-shaped cross section. A plurality of long grooves are formed in the length direction of the rod, and one end face of the rod tip end face that forms the gear-shaped mountain portion is fitted into a small hole formed at both ends of the snap ring and Two short pins capable of holding the retaining ring in a planar state in a compressed state are provided in a protruding manner, a lower collar is slidably attached to the outer periphery of the rod tip portion, and a long groove of the rod is attached to the inner periphery of the lower collar. A plurality of push-out pieces, which are slightly slidably shorter than the long groove, are fitted and fitted to the lower groove so as to project downward, and an upper brim having the same shape as the lower brim is fixed to the outer circumference above the long groove of the rod. Two bolts are inserted in the upper end of the lower collar and the lower end is fixed to the upper surface of the lower collar. A coil spring is wound around the minute bolt shaft, and the lower brim is biased so as to be pulled upward in the upper brim direction. First, the cylindrical body is fixed with a jig having a convex cross section in which an inserting portion having a height matching the lower edge of the predetermined annular groove into which the retaining ring is fitted is integrally formed, and then the rod is fixed. The snap ring is compressed in a plane and is engaged with the short pin at the tip of the rod, and the snap ring enters and descends into the cylinder to stop at a position slightly above the predetermined annular groove, and then the rod advances. A vertically downwardly and horizontally movable push-down member arranged in a lateral direction is inserted into the upper side of the lower collar, and the lower collar is pushed down by the pushing member to lower the lower end of the extrusion piece integrated with the lower collar. Push the retaining ring with to fit the retaining ring into the specified annular groove. Auto fitting method of retaining ring, characterized in that it was. 2. The first retaining ring according to claim 1, after being fitted into a predetermined annular groove at the inner side of the cylindrical body, the cylindrical body is reversed, and the second retaining ring is fitted at the upper end. The split chuck type jig having a height matching the lower edge of the other annular groove in the inner part of the power cylinder is inserted to fix the cylinder, and the center of the snap ring fitting rod tip surface is fixed. Is equipped with a taper-shaped protruding portion, and the rod is inserted into the cylindrical body while the second retaining ring is attached to the tip portion of the rod so that the rod is inserted into the upper end of the split chuck type jig, and the upper portion of the jig. And pushes it against the inner surface of the cylinder to stop the rod from entering slightly above the annular groove into which the retaining ring should be fitted, and then, similarly to the first aspect, the lower brim is formed by the U-shaped pressing member. Push down 2
An automatic fitting method for a snap ring, characterized by inserting a snap ring into a predetermined annular groove. 3. A snap ring fitting rod, which is slidably and slidably inserted in a cylinder having a plurality of annular grooves into which a snap ring is to be fitted, and a snap ring fitted into the cylinder from below. A jig having a convex cross-section integrally formed with an insertion portion having a height matching the lower edge of a predetermined annular groove into which the retaining ring is to be fitted first in the inner part of the cylinder, and the traveling direction of the rod. It is composed of a substantially U-shaped push-down member which is arranged laterally and can be vertically moved and horizontally moved by a cylinder. The snap ring fitting rod has a plurality of tips on its outer circumference so that its tip end has a gear-like cross section. A plurality of long grooves are formed in the length direction of the rod, and one end face of the rod tip end face that forms the gear-shaped mountain portion is fitted into a small hole formed at both ends of the snap ring and Two short pins that can hold the retaining ring in a compressed state in a plane are provided to project, and the rod tip A lower brim is slidably attached to the outer circumference, and a plurality of push-out pieces slightly shorter than the slidable long groove are fitted to the inner circumference of the lower brim, and a plurality of extruded pieces are projected and fixed downward. An upper brim having the same shape as the lower brim is fixed to the outer periphery above the long groove of the rod, two bolts are inserted into the upper brim, and the lower end is fixed to the upper surface of the lower brim, and the upper side of the upper brim is fixed. An automatic fitting device for a snap ring, characterized in that a coil spring is wound around a part of the bolt shaft, and the lower collar is biased so as to be pulled upward. 4. A snap ring fitting rod which is slidably and densely slidable in a cylinder having a plurality of annular grooves into which snap rings are to be fitted, and a snap ring having a second upper end to which a snap ring is to be fitted. A split chuck type jig that has a height that matches the lower edge of another annular groove in the back of the body, and a flat plane that is arranged laterally in the advancing direction of the rod and is vertically movable and horizontally movable by a cylinder. A U-shaped push-down member is provided, and a taper-shaped protruding portion is attached to the center of the tip end surface of the snap ring fitting rod so as to protrude into the upper surface of the split chuck type jig and push the jig open. An automatic snap-fitting device for a retaining ring. 5. An apparatus for engaging a retaining ring in a compressed state in a planar manner with a retaining ring fitting rod tip portion according to claim 3 or 4, wherein the guide is provided with a guide groove on the front side. A table, a slide slope slidable on the table along the guide groove, a guide block that is in contact with the upper surface of the slide plate and is located above the rear end of the guide groove, and is located above the guide block. The slide plate is formed with a circular concave recess capable of accommodating the retaining ring in a planar compression state on the upper surface of the front end thereof, and the slide plate has a protrusion at the bottom of the concave recess. A lifting piece is inserted, a shaft penetrating the bottom of the recess is vertically fixed to the center of the lower surface of the push-up piece, and a compression coil spring is wound around the outside of the bottom surface of the recess of the shaft. The push-up piece is biased so as to come into pressure contact with the inner bottom surface of the recess, A downward tapered taper guide hole reaching the lower surface is opened on the upper surface of the guide block, and the upper surface of the guide hole has a diameter such that a snap ring can be loosely fitted, and the lower surface is the above-mentioned concave portion. The first pushing rod has a diameter that can be inserted up to the middle portion of the tapered guide hole, and the second pushing rod has the same diameter as the lower surface of the guide hole. A push-up cylinder that has a diameter and that pushes up the shaft of the push-up piece that hangs downwardly of the recess at the forward end of the slide plate is arranged against the spring. A device for attaching a retaining ring to a distal end portion of a retaining ring fitting rod, comprising: