JPH11285927A - Piston pin press-in device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To forcibly fit a piston pin into a pin press-in hole smoothly without generating any bite in assembly of a piston and a connection rod. SOLUTION: A piston pin press-in device 20 is provided with a connection rod supporting mechanism 32 for holding a connection rod 2 horizontally in a predetermined position, a supporting structure 26 supporting a pin insertion hole peripheral part 1a on the piston side face, a guiding member 83 extending in the vertical direction, a pressing member 90, and a press-in unit 25 provided with an actuator and the like. The connection rod supporting mechanism 32 is provided with a floating pallet 42 supported in the floating condition by means of a spring 41. The supporting structure 26 is provided with a movable side supporting body 72 which is tiltable via a spherical joint part 71. A workpiece receiving face 75 is arranged in the movable side supporting body 72. The pressing member 90 is positioned on the same axial line with the guiding member 83.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston pin press-fitting device for press-fitting a piston pin into a pin press-fitting hole when assembling a connecting rod and a piston in an assembling process of an automobile engine, for example.

[0002]

2. Description of the Related Art As illustrated in FIG. 8, a piston 1 and a connecting rod 2 which constitute a part of an engine are connected to each other by a piston pin 3. The piston pin 3
With one end (small end 2a) of the connecting rod 2 inserted into the piston 1, it is inserted into the pin insertion hole 4 of the piston 1 and pressed into the pin pressing hole 5 of the connecting rod 2 by applying a press-fit load of 1000 kgf or more. You. Therefore, the piston pin 3 after press-fitting is rotatable relative to the pin insertion hole 4 of the piston 1, but the pin press-fit hole 5
Has a tight interference fit that cannot be rotated relative to.

Conventionally, as a device for press-fitting a piston pin 3, a piston pin press-fitting device 10 as shown in FIG.
Was used. The conventional device 10 includes a connecting rod 2
, A clamp mechanism 12 having an actuator such as a hydraulic cylinder, a work receiving surface 13 supporting a relatively flat portion 1a near the pin insertion hole on the side surface of the piston 1, and a A pressing member 14 and the like provided facing each other are provided. The pressing member 14 is driven vertically by an actuator such as a hydraulic cylinder,
A press-fit load is applied to the piston pin 3 from above.

When press-fitting the piston pin 3, one end (small end 2 a) of the connecting rod 2 is inserted into the piston 1, and the connecting rod 2 is actuated by the actuator of the clamp mechanism 12.
The other end of the piston pin 3b is firmly clamped at a predetermined position, and a portion 1a near the pin insertion hole on the side surface of the piston is supported by the work receiving surface 13 from below. Press-fit load.

[0005]

The conventional piston pin press-fitting device 10 raises the connecting rod 2 to a predetermined position by a clamp mechanism 12 in order to press-fit the piston pin 3 straight into the pin press-fitting hole 5 of the connecting rod 2. The large end 2b of the connecting rod 2 is firmly restrained on the support member 11 by the actuator of the clamp mechanism 12 in a state where the positioning is performed accurately.

However, the vicinity 1a of the pin insertion hole of the piston 1 in contact with the workpiece receiving surface 13 is a cast surface that has not been finished, so that the flatness is relatively rough, and the vicinity 1a of the pin insertion hole with respect to the horizontal plane. Or slightly tilted,
Some irregularities may be present. When a press-fit load P is applied to the piston pin 3 in a state where the pin insertion hole 1a having a rough flatness is supported by the work receiving surface 13, the piston 1 is slightly inclined according to the inclination of the work receiving surface 13 or the like. Sometimes.

[0007] In the case where such an inclination occurs, no matter how firmly the connecting rod 2 is restrained by the clamp mechanism 12, the pin press-in hole 5 or the piston pin 3 does not move in the press-in direction.
Are slightly inclined, for example, in the direction indicated by the arrow α in FIG. When the press-fitting proceeds, the piston pin 3
Of the pin insertion hole 4 or the pin press-fit hole 5 is pressed into the inner surface of the pin insert hole 4 or the pin press-fit hole 5, thereby causing a problem such as poor press-fit or damage to the inner surface of the pin insert hole 4 or the pin press-fit hole 5. .

Conventionally, it is assumed that the connecting rod 2 is firmly and precisely restrained at a predetermined position by the clamp mechanism 12, so that a large load is applied to the clamp mechanism 12 by an actuator such as a hydraulic cylinder to apply the connecting rod 2 to the connecting rod 2. Had been restrained. For this reason, there are problems that the number of actuators increases, the hydraulic circuit becomes complicated, and the cycle time of press fitting becomes long.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a piston pin press-fitting device which can avoid poor press-fitting of a piston pin and reduce cycle time when assembling a piston and a connecting rod.

[0010]

According to a first aspect of the present invention, there is provided a piston pin press-fitting device for achieving the above object, which is provided above a work receiving surface of a support structure before press-fitting a piston pin. The piston is placed so that the vicinity of the pin insertion hole on the side surface of the piston faces each other, and the piston is supported by the connecting rod support mechanism integrally with the connecting rod. Thereafter, the pressing member is lowered by an actuator such as a hydraulic cylinder from above the piston pin temporarily assembled to the piston, so that the piston pin is pressed toward the pin press-in hole.

At the time of this pressing, the connecting rod is held by the floating pallet having a floating function so as to be able to move forward. When the piston pin is pressed from above, the piston and the connecting rod are integrated with the floating pallet. It goes down. The piston is supported by the work receiving surface when the portion near the pin insertion hole on the side of the piston is lowered to a position where it comes into contact with the work receiving surface of the support structure.

When a press-fitting load is applied to the piston pin by further lowering the pressing member, the support member is supported in accordance with the inclination of the vicinity of the pin insertion hole on the side of the piston in contact with the work receiving surface of the support structure. The work receiving surface is tilted while moving the joint portion of the structure so as to follow the vicinity of the pin insertion hole, so that the work receiving surface is supported by the press-fitting load in a stable state.

For this reason, the piston pin and the pin press-fitting hole are aligned in the press-fitting direction irrespective of the position and the surface accuracy in the vicinity of the pin insertion hole, which causes the piston pin to bite the inner surface of the pin press-fitting hole during the press-fitting. Thus, the piston pin is prevented from being inclined, and the piston pin is pressed straight into the pin press-fitting hole.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings (FIGS. 1 to 8)
A piston pin press-fitting device 20 according to an embodiment of the present invention will be described with reference to FIG. The piston pin press-fitting device 20 of the embodiment shown in FIG. 1 is a device main body 2 as a highly rigid support structure constructed of various frame materials 21 and the like.
Two. The press-fit unit 2
5 are provided. A support structure 26 for receiving a press-fit load is provided below the apparatus main body 22.

A piston transfer mechanism 27 for transferring the piston 1 to the press-fitting stage S1 of the apparatus main body 22 is disposed on the left side of the support structure 26 in the figure. On the right side of the support structure 26 in the figure, a conveyor 28 that functions as a connecting rod transfer mechanism for transferring the connecting rod 2 to the press-fitting stage S1 of the apparatus main body 22 is arranged.

The conveyor 28 is provided with a connecting rod support mechanism 32 which is moved by a chain 31. The connecting rod support mechanism 32 is stopped at the press-fitting stage S1 of the apparatus main body 22 by the stopper mechanism 33.

As shown in FIGS. 3 to 5, the connecting rod support mechanism 32 includes a mounting table 4 that moves integrally with the chain 31.
0, and a floating pallet 42 provided on the mount 40 in a floating state by a spring 41. The floating pallet 42 can be smoothly moved up and down along a guide member 43 which expands and contracts in the vertical direction.

The floating pallet 42 includes a spring 41
And the rising end thereof is regulated by a stopper 44 and is kept in a horizontal posture. The spring 41 and the floating pallet 42 constitute floating means according to the present invention.

The floating pallet 42 has a projection 5 into which the bearing hole 2c of the connecting rod 2 is fitted so that the connecting rod 2 can be held at a predetermined position in a posture of being laid sideways.
0, a locking portion 51 into which the middle portion 2d in the longitudinal direction of the connecting rod 2 is fitted, a pair of clamp members 52 (shown in FIG. 4) for holding the large end 2b of the connecting rod 2 from both sides.

Each of the clamp members 52 is rotatable about a shaft 53 extending in the horizontal direction, and has a clamp arm 54 projecting upward and a release lever 55 extending in the lateral direction. The pair of clamp arms 54 are urged by a spring 56 in a direction to close each other, that is, a direction to hold the large end 2b of the connecting rod 2 from both sides.

In addition, the clamp member 52 allows each release lever 55 to be unclamped by a member 57 (only a part is shown in FIG. 4).
By pressing in the direction of arrow F from above, each clamp arm 54 opens in the direction of
Is configured to be able to move in a direction of releasing (unclamping direction).

The piston transport mechanism 27 shown in FIG. 1 includes a piston conveyor 60 for feeding the pistons 1 one by one in a posture in which the axis is tilted sideways, and a piston transfer mechanism 61 located above the piston conveyor 60. ing. The piston transfer mechanism 61 includes a chuck section 62 for gripping the piston 1 and an elevating mechanism 63 for driving the chuck section 62 up and down.
And a transverse feed mechanism 6 for driving the chuck portion 62 in the horizontal direction.
4 is included.

The piston 1 transferred by the piston conveyor 60 is conveyed to the piston transfer stage S2 with the piston pin 3 inserted halfway from above the pin insertion hole 4. The chuck part 62 simultaneously holds the piston 1 and the piston pin 3 in the piston transfer stage S2, and then integrally transfers the piston 1 and the piston pin 3 to the press-fitting stage S1 (a position directly below the press-fitting unit 25). .

The support structure 26 for receiving the press-fit load transmitted from the piston pin 3 is configured as shown in FIGS. The support structure 26 is provided in the device main body 2.
2 and a fixed-side support 70 fixed to
Is provided with a movable-side support member 72 rotatably provided on the upper surface side via a spherical joint portion 71. That is, the movable-side support member 72 constitutes a universal joint that can be tilted in all directions with respect to the axis X in the vertical direction in an angle range of several degrees with respect to the neutral position.

The upper end of the movable-side support 72 is a flat work receiving surface 75 facing the pin insertion hole vicinity 1a on the side surface of the piston 1, and is in surface contact with the pin insertion hole vicinity 1a. To make it possible. The work receiving surface 75 is a surface extending in the horizontal direction when the movable-side support 72 is at the neutral position. A center hole 76 is formed in the fixed-side support 70 and the movable-side support 72 so as to penetrate vertically.

A guide mechanism 80 is provided near the lower portion of the support structure 26.
Is provided. The guide mechanism 80 includes a center guide shaft 81 located on a vertical axis X, a vertically extending guide member 83 having a guide pipe 82 concentrically provided on the outer peripheral side of the center guide shaft 81, and a guide member 83 extending vertically. An actuator 84 (shown in FIG. 1), such as a hydraulic cylinder, for driving the 83 up and down is provided. The center guide shaft 81 is relatively movable with respect to the guide pipe 82 in the direction of the axis X (vertical direction), and is urged upward by a spring 85.

When the guide member 83 is moved to the rising end by the actuator 84, the center guide shaft 81 enters the inside of the piston pin 3 and the guide pipe 82 is connected to the pin press-fit hole 5 of the connecting rod 2 as shown in FIG. And rises to a position protruding upward. The upper end portion 82a of the guide pipe 82 has a tapered shape such that the outer diameter on the upper end side is reduced, and when the upper end portion 82a is fitted into the lower end opening of the piston pin 3, the piston pin 3 and the guide pipe 82 are connected. Centering (that is, centering of the piston pin 3 and the guide member 83) is performed.

As shown in FIG. 1 and the like, the guide mechanism 80
A press-fit unit 25 is provided above. The press-fit unit 25 includes a pressing member 90 located on an extension of the axis of the guide member 83 (the axis X in the vertical direction) and a pressing member 9.
An actuator 91 such as a hydraulic cylinder for driving the vertical movement of the pressing member 90 in the vertical direction, a linear bearing 92 for guiding the vertical movement of the pressing member 90, and a sensor 93 for detecting the vertical position of the pressing member 90 are provided. .

The pressing member 90 has a press-fit head 9 at its lower end.
5 is provided. The press-fit head 95 has a centering member 96 having a pointed tip at the center. FIG.
As shown in the figures, the centering member 96 is urged by a spring 97 in a direction protruding downward from the press-fitting head 95, and is fitted into the upper end opening of the piston pin 3 so that the piston pin 3 and the pressing member 90 Centering (centering) of each other is performed.

The pressing member 90 includes an actuator 91
The operation stroke and the like are set so that the press-fit head 95 press-fits the piston pin 3 into the pin press-fit hole 5 of the connecting rod 2 to a predetermined press-fit position when moved to the lower end.

Next, the operation of the piston pin press-fitting device 20 will be described. The conveyer 28 conveys the connecting rod 2 to the press-fitting stage S1 of the apparatus main body 22. The connecting rod 2 is held by a connecting rod support mechanism 32 in a posture in which the connecting rod 2 is horizontally inclined at a predetermined position.
The mounting table 40 of the connecting rod support mechanism 32 is stopped by the stopper mechanism 33 (shown in FIG. 1),
The positioning of the connecting rod 2 is performed.

Thereafter, the unclamping member 57 (only part of which is shown in FIG. 4) descends from above the connecting rod support mechanism 32 toward the release lever 55, and the release lever 55 is
Press in the direction. Thereby, since the clamp arm 54 moves in the direction to release the connecting rod 2, the connecting rod 2 can be freely moved to some extent.

On the other hand, the piston 1 is transported to the piston transfer stage S2 by the piston conveyor 28 shown in FIG. The piston 1 is gripped by the chuck portion 62 of the piston transfer mechanism 61 together with the piston pin 3, and the lifting mechanism 63 and the traverse mechanism 64 are operated in the directions of arrows A and B in FIG.
Is loaded into the press-fitting stage S1 in the horizontal position, and the horizontal piston 1 is fitted to the small end 2a of the connecting rod 2 from the horizontal direction. At this time, as shown in FIG. 2, the portion 1 a of the piston 1 in the vicinity of the pin insertion hole is spaced and opposed directly above the work receiving surface 75.

When the guide member 83 is lifted from below the support structure 26 by the actuator 84, the center guide shaft 81 is inserted into the piston pin 3 as shown in FIG. It is inserted into the lower pin insertion hole 4 and the pin press-fit hole 5 of the connecting rod 2. By doing so, the pin insertion hole 4, the piston pin 3, and the core of the guide pipe 82 are aligned. Thereafter, the unclamping member 57 is raised, and the connecting rod 2 is clamped by the clamp arm 54.

In this state, the pressing member 90 is lowered by the actuator 91, and the centering member 96 of the press-fit head 95 is fitted into the upper end opening of the piston pin 3, so that the center of the piston pin 3 and the pressing member 90 are aligned. Fit. When the press-fit head 95 further descends while the press-fit head 95 is in contact with the upper end of the piston pin 3, the floating pallet 42 descends integrally with the piston 1 and the connecting rod 2 against the reaction force of the spring 41.

For this reason, the piston 1
, And the piston 1 is supported by the work receiving surface 75. In this case, the piston 1, the connecting rod 2, and the floating pallet 4 are moved to a height corresponding to the vertical dimension of the piston 1.
2 descends together, so that the dimensional variation of the piston 1 can be absorbed and the connecting rod 2
Connecting rod support mechanism 32 and connecting rod 2
No excessive load such as bending is applied to the cable.

Although the work receiving surface 75 is finished flat, the vicinity 1a of the pin insertion hole of the piston 1 is a so-called cast surface and has poor flatness. When the vicinity 1a is pressed, the spherical joint 71 is displaced (tilted) in accordance with the unevenness or inclination of the vicinity 1a of the pin insertion hole, so that the movable-side support 72 finally settles in a stable posture.

For this reason, even if the surface accuracy of the portion 1a near the pin insertion hole is poor, the piston 1 is kept in a fixed posture (the posture in which the axis of the piston is oriented in the horizontal direction), and the pin insertion hole 4 and the pin press-fit hole 5 are kept. Verticality is maintained. Moreover, the work receiving surface 7
5 and the pin insertion hole vicinity 1a are in uniform surface contact. The pressing member 9 is arranged on the same axis as the guide member 83.
0 will be located. For these reasons, the inclination of the piston pin 3 at the time of press-fitting is avoided, and the press-fitting load by the pressing member 90 can be applied straight along the axis of the piston pin 3 (vertical axis X).

The press-fitting proceeds as described above, and the press-fitting actuator 91 operates to the lower end, whereby the piston pin 3 is press-fitted to a predetermined position of the pin press-fitting hole 5. When the press-fitting is completed, the detected portion 94 of the actuator 91 is detected by the sensor 93, and when the actuator 91 stops, the pressing member 90 also stops.

Thereafter, the actuator 91 is moved upward to raise the pressing member 90, and the piston 1 after completion of the press-fitting is carried out to the next process by the conveyor 28, thereby completing one cycle of the press-fitting process. Then, the new piston 1, the piston pin 3, and the connecting rod 2 are carried into the press-fitting stage S1, and the above-described press-fitting process is repeated.

[0041]

According to the piston pin press-in device of the present invention, when the piston pin is press-fitted, the vicinity of the pin insertion hole on the side surface of the piston which comes into contact with the work receiving surface is like a casting surface. Even if the flatness is not good, it is possible to prevent the piston pin from being inclined at the time of press fitting. For this reason, poor press-fitting, such as galling of the piston pin into the pin press-fitting hole, can be prevented, and the piston pin can be smoothly press-fitted with a predetermined press-fitting load.

Further, the connecting rod supporting mechanism employed in the present invention does not rigidly restrain the connecting rod at a predetermined position as in the conventional clamping mechanism, but holds the connecting rod so as to be displaceable by a floating pallet. This eliminates the need for an actuator such as a hydraulic cylinder such as the clamp mechanism described above, so that the cycle time can be reduced and the hydraulic system and the like can be simplified.
Further, by adopting a floating pallet which descends to a height corresponding to the dimensions of various pistons at the time of press-fitting, dimensional variations of the pistons can be easily absorbed.

[Brief description of the drawings]

FIG. 1 is a side view partially showing a cross section of a piston pin press-fitting device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a part of the piston pin press-fitting device shown in FIG.

FIG. 3 is a plan view of a connecting rod support mechanism of the piston pin press-fitting device shown in FIG. 1;

FIG. 4 is a front view of the connecting rod support mechanism shown in FIG. 3;

FIG. 5 is a sectional view taken along the line VV in FIG. 3;

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 2;

FIG. 7 is a cross-sectional view of the piston pin press-fitting device shown in FIG. 1 after the piston pin is press-fitted.

FIG. 8 is a perspective view showing a piston, a connecting rod, and a piston pin.

FIG. 9 is a sectional view showing a conventional piston pin press-fitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piston 1a ... Pin insertion hole vicinity 2 ... Connecting rod 3 ... Piston pin 5 ... Pin press-in hole 20 ... Piston pin press-in device 25 ... Press-in unit 26 ... Supporting structure 32 ... Connecting rod support mechanism 42 ... Floating pallet 71 ... Joint part 75 ... Work receiving surface 80 ... Guide mechanism 90 ... Pressing member 91 ... Actuator

Claims (1)

[Claims] A piston pin press-fitting device for assembling a connecting rod and a piston by fitting a connecting rod and a piston and press-fitting a piston pin, wherein the connecting rod is supported in a horizontal position. A connecting rod support mechanism having a floating pallet for supporting the connecting rod in a floating manner, and a work receiving surface for supporting a portion near the insertion hole of the piston pin provided on the piston from below, and in a direction in which the piston pin is inserted. A support structure having a joint portion that can be tilted with respect to an axis along the guide line, a guide member that can be inserted into a pin press-fit hole at an end of a connecting rod inserted through the support structure and inserted into the piston, and above the guide member. An ascending and descending pressing member that is installed and faces an end face of a piston pin inserted into the piston; Piston pin press-fitting apparatus characterized by comprising an actuator, a press-fitting the Sutonpin in the pin fitting hole by pressing by the pressing member.