JP2518280B2 - Assembly device for piston ring - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for automatically assembling a piston ring to a piston of an engine.

[Conventional technology]

As the prior art related to the present invention, Japanese Utility Model Laid-Open No. 56-109828
Japanese Laid-Open Patent Publication No. 57-140931 is known.

The piston ring mounting device disclosed in Japanese Utility Model Laid-Open No. 56-109828 described above is configured such that when the piston ring is mounted in the ring groove of the piston, the regulation member restricts the local expansion of the piston ring. The piston ring is prevented from being out of roundness after the insertion.

The piston ring supply assembling apparatus disclosed in Japanese Utility Model Laid-Open No. Sho 57-140931 is one in which an oil ring and a pair of compression rings are simultaneously assembled in respective ring grooves of a piston.

When assembling a piston ring with a strong expansion force, such as a spacer expander ring, on a piston of an engine, etc., the inner diameter of the piston ring is temporarily expanded by a guide member such as a taper cone, and then the piston ring contracts due to self-tension. It is installed in the ring groove of the diameter piston. As an example of an apparatus for assembling a piston ring by such a method, a piston ring assembling machine described on page 100 of "Mechanical Design" published by Nikkan Kogyo Shimbun in March 1986 is known. Has been.

FIG. 5 shows a cross section of a main part of the piston ring assembling machine described in the above “machine design”. This piston ring mounting machine 1 has a magazine 3 into which the piston rings 2 stacked on the outer periphery are fitted. The magazine 3 is formed with a taper cone 4 composed of a taper portion 4a and a straight portion 4b, the diameter of which increases as it goes upward. Below the magazine 3, a feeding means 5 for pushing up the piston ring 2 fitted in the magazine 3 is arranged. A concave portion 4d is formed on the top surface 4c of the tapered cone 4, and a receiving member 6 is arranged in the concave portion 4d. The piston 7 on which the piston ring 2 is mounted is placed on the receiving member 6 in the recess 4d, and the top surface 4c of the tapered cone 4 and the ring groove 7a of the piston 7 are aligned with each other.

In such a device, the piston ring 2 fitted in the magazine 3 is always pushed out by the feeding means 5 by a constant distance. And the taper part of the taper cone 4
After reaching the straight portion 4b, the piston ring 2 whose inner diameter is expanded by 4a is disengaged from the tip of the tapered cone 4 and mounted in the ring groove 7a of the piston 7 by the self-elastic force.

[Problems to be solved by the invention]

A piston ring with high processing accuracy such as a compression ring has almost no variation in the total thickness when a plurality of layers are stacked. Therefore, even if a device that pushes the piston ring out a certain distance as shown in Fig. 5 is used, In this case, the positional deviation between the piston ring and the ring groove of the piston is very small, and the piston ring can be easily mounted in the ring groove.

However, the spacer expander ring has a large thickness tolerance of ± 0.15 mm, and if the extrusion method with a constant feed rate by the stacking method is applied as described above, the piston ring and ring groove will not be Since the position of is greatly displaced, the piston ring cannot be properly fitted in the ring groove. That is, of the stacked piston rings, the upper one has a small cumulative error and therefore matches well with the ring groove, but the lower one, which has a large cumulative error, has a large misalignment between the piston ring and the ring groove. There is a problem that the phenomenon such as two sheets coming off or not being attached easily occurs.

The present invention focuses on the above problems, and an object thereof is to provide an assembly device for a piston ring that can reliably mount the piston ring in the ring groove of the piston, even if the thickness of the piston ring varies greatly. To do.

[Means for solving problems]

A piston ring assembling apparatus according to the present invention that meets this object is a magazine having a tapered cone in which a plurality of stacked piston rings are fitted to the outer periphery and the inner diameter of the piston rings can be gradually increased, and the piston rings. Feeding means for pushing up from the base end portion of the magazine toward the tapered cone portion, gripping means for grasping the piston to which the piston ring is attached, and conveying means for mounting the grasped means and the grasped piston in the magazine, The distance between the ring groove of the piston provided in the gripping means and set in the magazine and the piston ring located at the uppermost stage is measured so that the position of the piston ring at the uppermost stage is always a constant distance with respect to the ring groove. Height measuring means for adjusting the feed amount of the feeding means.

[Action]

In the piston ring assembling device configured as described above, the plurality of stacked piston rings are expanded to a predetermined inner diameter by the feeding means and the taper cone of the magazine, and then mounted one by one in the ring groove of each piston. To be done. In this case, the feed amount of the feeding means is adjusted by the height measuring means such that the uppermost piston ring and the ring groove of the piston always have a constant distance. Therefore, even if there is variation in the thickness of the piston ring, the correction of this feed amount always pushes the uppermost piston ring up to a position where it can be easily attached to the ring groove, and the piston ring is securely attached to the ring groove. To be done.

〔Example〕

Hereinafter, a preferred embodiment of an assembly device for a piston ring according to the present invention will be described with reference to the drawings.

1 to 3 show an assembly device for a piston ring according to an embodiment of the present invention. In the figure, 11 indicates a piston in which a ring groove 12 is formed. Reference numeral 13 denotes a spacer expander ring as a piston ring that is mounted in the ring groove 12 of the piston 11. The spacer expander ring 13 has a greater variation in thickness accuracy than the compression ring.

The piston 11 is a hand of the robot 14 as a transportation means.
It is adapted to be grasped by a grasping means 15 attached to 14a. The robot 14 is movable in the directions of arrows X, Y, and Z as shown in FIG. 1, and sets the piston 11 not equipped with the spacer expander ring 13 from another process to a magazine described later or the spacer. After the expander ring 13 is attached, the piston 11 is transported to another process.

In FIG. 1, reference numeral 22 denotes a magazine in which a plurality of stacked spacer expander rings 13 are fitted on the outer circumference. The magazine 22 is composed of a substantially cylindrical magazine body 23 and a taper cone 24. As shown in FIG. 2, the taper cone 24 is detachably fixed to the top of the magazine body 23 and has a larger diameter as it goes upward.
Straight portion 24b connected to the large diameter side of 24a and the tapered portion 24a
And have. A circular recess 24d is formed in the top portion 24c of the taper cone 24, and the piston 11 to which the spacer expander ring 13 is attached can be placed in the recess 24d. In this case, the top surface 11a of the piston 11 is the recess 2
It is set so as to contact the bottom surface 24e of 4d. The magazine 22 is fixed to the upper plate 17a of the frame 27, and below the magazine 22, a feeding means 25 for pushing out the spacer expander ring 13 fitted in the magazine 22 from the base end portion 23a toward the tapered cone 24. Is provided.

The feeding means 25 has a pressing plate 26 located on the outer periphery of the magazine body 23, and the pressing plate 26 is connected to the upper ends of a plurality of slide shafts 29 penetrating the upper plate 17a of the frame 27. The slide shaft 29 is a guide sleeve 2 below the upper plate 17a.
It is slidably housed in 8. The other of the slide shafts 29 is fixed to the base plate 31. A ball nut 32 is attached to the center of the base plate 31.
The ball nut 32 is screwed with a ball screw shaft 33 located on the same axis as the magazine 22 and arranged inside the plurality of guide sleeves 28. The ball screw shaft 33 is rotatably supported by a bearing 34 fixed to the guide sleeve 28 side. At the lower end of the ball screw shaft 33, the driven pulley 23
a is installed. This driven pulley 23a is a frame
A driving pulley 25a attached to a stepping motor 35 arranged in 27 is connected via a timing belt 26. In other words, when the ball screw shaft 33 is rotated by the stepping motor 35, the ball nut 32 moves to the ball screw shaft 33.
The pressing plate 26 located on the outer circumference of the magazine 22 is moved up and down to move up and down.

The stepping motor 35 is driven by a pulse signal from a control device (not shown).

Above the magazine 22, the gripping means 15 attached to the hand 14a of the robot 14 is located. Hand 14a
This is a parallel grip type chuck with a built-in actuator, and a pair of movable claws 100a and 100b are provided at the lower end thereof, and they move in parallel in the direction of arrow A, respectively. The gripping means 15 is a mounting bracket.
42 and a pair of grips 50. Mounting bracket 42
Is fixed to the hand 14a by a bolt 42a. Grip
50 is a movable claw 100a of the chuck body 14a by a bolt 68a,
It is fixed at 100b. The grip 50 is an L-shaped chuck.
68, a center 70, and a compression coil spring 72. The center 70 is slidably held by a chuck 68, and a compression coil spring 72 for biasing the center 70 in the center direction is interposed between the center 70 and the chuck 68. Therefore, by driving the movable claws 100a and 100b of the chuck body 14a, the piston 11 is gripped by each center 70 urged by the compression coil spring 72.

Further, the height measuring means 40 is attached to the mounting bracket 42 of the gripping means 15.
Is provided. The sliding ball bearing 52, which constitutes a part of the height measuring means 40, is attached to the attachment fitting 42 by a circlip 48. Sliding ball bearing 52
A guide pin 46 is slidably inserted in the stopper pin 46a that bulges outward in the radial direction at the upper end of the guide pin 46.
Are formed. At the lower end of the guide pin 46, a movable member 56
Are connected by a nut 46b. An actuator 44 is located near the guide pin 46, and the actuator 44 is fixed to the mounting bracket 42 side. The rod 44b of the actuator 44 is screwed with the movable member 56, and both are stopped by the nut 44a screwed with the rod 44b.

Two sliding ball bearings 58 are fitted to the lower portion of the movable member 56. Ball bearings for sliding 58
Is provided parallel to the axis of the rod 44b of the actuator 44, and is supported by the retaining plate 60 attached to the lower surface of the movable member 56. A shaft 62 is slidably inserted in each of the sliding ball bearings 58. A stopper 62a that bulges outward in the radial direction is formed at the upper end of the shaft 62. A contact plate 66 capable of contacting the spacer expander ring 13 as a piston ring is attached to the lower end of the shaft 62 by a nut 62b.

The contact plate 66 has an R shape (arc) slightly larger than the outer shape of the tapered cone 24, and the contact plate 66 and the uppermost spacer expander ring 13 can come into contact with each other. As a result, the contact plate 66 is movable in the vertical direction by coming into contact with the spacer expander ring 13.

A detection plate 64 is screwed on the upper end of one shaft 62.
Installed by 64a. A proximity switch 54 as a distance sensor is provided at a position facing the detection plate 64. The proximity switch 54 is fixed to the movable member 56 by two nuts 54. The proximity switch 54 is movable in the axial direction, and the distance to the detection plate 64 can be variably set.

The proximity switch 54 is connected to a control device (not shown), and the proximity switch 54 controls the stepping motor 35. That is, when the upper end surface 13a of the spacer expander ring 13 is at the same height as the upper surface 12a of the ring groove 12, the proximity switch 54 outputs an ON signal to the control device, and based on this signal, the rotation of the stepping motor 35 is rotated. Is to be stopped.

Next, the operation and the assembling order of the piston ring assembling device will be described.

The piston 11 is a hand of the robot 14 as a transportation means.
The recess 24 formed in the taper cone 24 of the magazine 22 is grasped by the grasping means 15 attached to the 14a and is formed from another process.
set to d. As a result, the piston 11 is positioned at a predetermined position with the top surface 11a facing downward, as shown in FIG.

When it is confirmed that the positioning of the piston 11 is completed, the stepping motor 35 rotates and the ball screw shaft 33 is rotationally driven. The ball nut 32, whose movement in the rotational direction is stopped by the slide shaft 29, moves upward in FIG. 1, and the plurality of spacer expander rings 13 mounted on the outer periphery of the magazine 22 are pushed up by the pressing plate 26. Spacer expander ring 13 pushed up is tapered cone
The diameter is expanded by 24 taper portions 24a and reaches the straight portion 24b connected to the large diameter side of the taper portion 24a.

The movable member 56 of the height measuring means 40 is pushed down by the actuator 44 before the piston 11 is set. This position is set at a position where the lower end surface 66a of the contact plate 66 lowered by its own weight and the uppermost upper surface of the spacer expander ring 13 coincide with each other, as shown in FIG.

The spacer expander ring 13 raised by the rotation of the stepping motor 35 comes into contact with the contact plate 66, and the contact plate 66 is moved upward by pushing up the spacer expander ring 13 as shown in (b) of FIG. . When the contact plate 66 moves upward, the distance a between the detection plate 64 and the proximity switch 54 becomes narrow, and when the distance becomes smaller than a predetermined value, the proximity switch
54 turns on. That is, the proximity switch 54 outputs an ON signal to the control device when the upper end surface 13a of the spacer expander ring 13 becomes substantially the same height as the upper surface 12a of the ring groove 12, and the rotation of the stepping motor 35 is stopped. It

Therefore, the spacer expander ring 13 is removed from the taper cone 24 and, at the same time, is easily attached to the ring groove 12 of the piston 11 by the self-elastic force.

When the spacer expander ring 13 is mounted in the ring groove 12, the actuator 44 operates and the contact plate 66 rises. Here, the reason why the contact plate 66 is raised is to prevent the contact plate 66 and the shaft 62 from bearing their own weight on the next ring. Then, the piston 11 with the ring attached is conveyed to the next process by the robot 14.

In this embodiment, the spacer expander ring is described as an example of the piston ring, but it goes without saying that it can be used for other piston rings.

〔The invention's effect〕

As described above, in the case of the piston ring assembling apparatus of the present invention, by adjusting the feed amount of the feeding means by the height measuring means, the piston in the uppermost stage among the plurality of piston rings set in the magazine is adjusted. The position of the ring can always be a fixed distance from the piston ring groove, and even if there is a large variation in the thickness of the piston ring, the piston ring at the top is always pushed to the position where it is most easily fitted in the ring groove. The piston ring can be securely attached to the piston.

Therefore, the phenomenon such as the two pieces coming off during assembly or the non-equipment, which occurred in the conventional apparatus, can be completely prevented, and the inspection cost can be reduced.

[Brief description of drawings]

FIG. 1 is an overall sectional view of an assembly device for a piston ring according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view in the vicinity of a magazine in FIG. 1, and FIG. 3 is a hand of a conveying device in FIG. An enlarged cross-sectional view of the vicinity, (a) to (c) of Fig. 4 are cross-sectional views showing the assembled state of the piston ring in the device of Fig. 1, and Fig. 5 is a cross-sectional view of the main part of a conventional piston ring assembly machine. Fig. 11 …… Piston 12 …… Ring groove 13 …… Piston ring (spacer expander ring) 14 …… Transport means (robot) 15 …… Grip means 22 …… Magazine 24 …… Taper cone 25 …… Feed means 40 …… High Measuring means 54 ... Distance sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shozo Kobayashi 1 Toyota-cho, Toyota City Toyota Motor Corporation (56) References: 62-74928 (JP, U)

Claims (1)

(57) [Claims] 1. A magazine having a tapered cone in which a plurality of stacked piston rings are fitted to the outer periphery and the inner diameter of the piston ring can be gradually increased, and the piston ring is directed from the base end portion of the magazine toward the tapered cone portion. A feed means for pushing up, a gripping means for grasping the piston on which the piston ring is mounted, a conveying means for mounting the grasped means and setting the grasped piston in a magazine,
The distance between the ring groove of the piston provided in the gripping means and set in the magazine and the piston ring located at the uppermost stage is measured so that the position of the piston ring at the uppermost stage is always a constant distance with respect to the ring groove. A height measuring means for adjusting the feed amount of the feed means, and a piston ring assembling device comprising: