JP2000198030A - Piston inserting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly insert a piston, in a piston inserting device for pressing a piston to be inserted and set in a rough guide cylinder into a cylindrical hole of a cylinder block through a guide cylinder. SOLUTION: In this piston inserting device, a guide cylinder 3 having a taper part 3t is connect to a cylindrical hole Wh of a cylinder block W, a rough guide cylinder 6 is connected to the guide cylinder 3, and a piston P to be set in the cylinder of the rough guide cylinder 6 is pressed in the cylinder hole Wh by a press-in member. In this case, an inside diameter extending part 6d is provided near the lower end opening part of the rough guide cylinder 6 to prevent the piston P from being tilted when a skirt part Ps of the piston P approaches the taper part 3t.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for inserting a piston into a cylinder of a cylinder block of an engine.

[0002]

2. Description of the Related Art Conventionally, as a device for inserting a piston into a cylinder hole of a cylinder block of a vehicle engine, for example, an insertion device as disclosed in JP-A-79271 is known. As shown in FIG. 8, a guide cylinder 52 connected to the upper part of the cylinder hole Wh of the cylinder block W so that its axis is aligned, a rough guide cylinder 53 connectable to the upper part of the guide cylinder 52, and a rough guide cylinder 53 A movable plate 54 for supporting the cylinder 53 and a pushing member 55 for pressing the piston P inserted and set in the rough guide cylinder 53 downward are provided. The guide cylinder 52 is initially positioned above the cylinder hole Wh of the cylinder block W. Then, the rough guide cylinder 53 is horizontally moved and retracted from the upper part of the guide cylinder 52, and as shown in FIG. At the same time as aligning the two axes, the piston P is inserted and set into the retracted rough guide cylinder 53, and then the pushing member 55 is raised. Then, as shown in FIG. The piston P is moved right above the guide cylinder 52 and set, and the pushing member is lowered again to push the piston P into the cylinder hole Wh of the cylinder block W.

[0003] In such a piston insertion device 51, even if the axis of the rough guide cylinder 53 is slightly displaced with respect to the guide cylinder 52, the piston P can be inserted smoothly near the upper end opening of the guide cylinder 52 so that the piston P can be inserted smoothly. The inner surface is formed with a tapered portion 52t whose diameter increases upward.

[0004]

However, in the above-described piston insertion device 51, the skirt portion Ps of the piston P approaches the tapered portion 52t due to the degree of axial misalignment between the rough guide cylinder 53 and the guide cylinder 52. At this point, the attitude of the piston P is inclined and pushed in, and the guide cylinder 52 is pryingly displaced from the cylindrical hole Wh, and the skirt portion Ps of the piston P is hooked at the entrance of the cylindrical hole Wh.

Accordingly, the present invention provides a piston insertion device in which a guide cylinder is connected to a cylinder hole of a cylinder block, and a rough guide cylinder is connected thereon to insert a piston. It is intended to be constituted.

[0006]

To achieve the above object, the present invention provides a guide cylinder connected to an opening of a cylinder hole of a cylinder block, and a rough guide cylinder connected to an upper end opening of the guide cylinder. A push member is provided for pressing the piston set in the rough guide cylinder downward, and a tapered portion whose inner diameter increases upward on the inner surface near the upper end opening of the guide cylinder increases the height of the piston. In a piston insertion device formed not to exceed the length range, an inner diameter expanding portion is provided on the inner surface near the lower end opening of the rough guide cylinder to absorb the inclination of the attitude of the piston caused by the tapered portion. The length range from the lower end opening of the rough guide cylinder is at least the difference between the height of the piston and the length range of the tapered portion.

That is, when the piston descends from above and the skirt portion approaches the tapered portion, the posture of the piston is inclined when the misalignment between the rough guide cylinder and the guide cylinder is large, and thereafter the posture is inclined. When the piston is pushed in, the skirt portion of the piston becomes hooked at the entrance of the cylindrical hole. Thus, by slightly increasing the inner diameter of the inner peripheral portion on the lower end side of the rough guide cylinder, the inclination of the posture when the skirt portion of the piston passes through the tapered portion is absorbed, and the upright posture is maintained.

At this time, if the total of the length range of the tapered portion and the length range of the enlarged inner diameter portion exceeds the height of the piston, the posture can be corrected. Set to. Here, the height of the piston is based on the height of the portion where the axial length is the maximum in the sliding contact surface on the outer surface of the piston.

The amount of expansion of the inner diameter of the inner diameter expanding portion is determined to an appropriate value depending on the positional deviation error between the rough guide cylinder and the guide cylinder, the piston diameter, and the like. The inner diameter of (φ81 + 0.0
In the case of 5) to (φ81 + 0.10), setting the inner diameter of the inner diameter enlarged portion to about φ82.0 to φ82.5 can correct the inclination of the piston and also does not impair the guide function, which is preferable. is there.

[0010]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is a side view of the piston insertion device according to the present invention, FIG. 2 is a front view thereof, FIG. 3 is a plan view thereof, FIG. 4 is an enlarged view of FIG. 1, and FIG. FIG. 6 is an enlarged view of a main part of FIG.

[0011] A piston insertion device according to the present invention prevents a trouble that a piston is caught in an inlet when a piston is inserted into a sleeve of a cylinder block of a vehicle engine, for example. In particular, it is characterized by the inner surface structure of the rough guide cylinder on which the piston is set first.

In the embodiment, as shown in FIGS. 1 to 3, the piston insertion device 1 is provided near a work carrying path R for carrying a cylinder block W of a four-cylinder engine. A base plate 2 provided on an upper portion of the base plate, four guide cylinders 3 supported by the base plate 2, a base 4 erected near the work carrying path R,
A movable plate 5 that can move horizontally with respect to the base 4, and four rough guide cylinders 6 supported by the movable plate 5.
An elevating body 7 that can move up and down with respect to the base 4, and a pushing member 8 attached to the elevating body 7, and a lower part of the base 4 for driving the movable plate 5. A horizontal cylinder unit 10 is provided, and a vertical cylinder unit 11 for driving the elevating body 7 is provided above the base 4.

When the cylinder block W is conveyed and positioned at a predetermined position, the guide cylinder 3 supported by the base plate 2 is set on the cylinder hole Wh of the cylinder block W, and the pushing member 8 descends. The positioning is performed with the axis aligned with the cylindrical hole Wh. On the other hand, the rough guide cylinder 6 is located at a set portion at a position deviated from the axis of the guide cylinder 3 due to the advance of the movable plate 5 as shown by a chain line in FIG. After the piston P is inserted and set in the rough guide cylinder 6 by the operator, the movable plate 5 is retracted to the position indicated by the solid line in FIG. 4 by NC control or the like, and the rough guide cylinder 6 is set on the upper part of the guide cylinder 3. . At this time, the lower surface of the guide cylinder 3 comes into communication with the cylinder hole Wh in a state of contact with the upper surface of the cylinder block W, and the lower surface of the rough guide cylinder 6 comes into contact with the upper surface of the guide cylinder 3 in a state of contact.

In this state, the elevating body 7 descends, and the pushing member 8 is inserted into the cylinder hole Wh of the cylinder block W from each of the rough guide cylinders 6 through each of the guide cylinders 3. The piston P set in the cylinder is pushed into the cylinder hole Wh of the cylinder block W.

Here, as shown in FIG. 5, a tapered portion 3t whose inner diameter increases toward the upper opening side is formed on the upper side of the inner peripheral surface of the guide tube 3, and the rough guide tube 6 and the guide tube 3 are formed.
Even if there is some misalignment between them, the piston P is prevented from being caught at the entrance of the guide cylinder 3,
In the conventional structure, when the skirt portion Ps of the piston P passes through the tapered portion 3t, the posture of the piston P may be inclined. It is as described above that a problem of being trapped at the entrance of the cylindrical hole Wh may occur.

Therefore, according to the present invention, an inner diameter expanding portion 6d whose inner diameter is slightly widened is formed on the inner peripheral portion of the rough guide cylinder 6 at the lower side, and the inner diameter expanding portion 6d absorbs the inclination of the piston P and stands upright. The posture can be maintained.

The length range d from the lower end opening of the inner diameter enlarged portion 6d is, as shown in FIG.
From the relationship between the length range t from the upper end opening of t and the height h of the piston P, at least d> ht,
The skirt portion Ps enters the tapered portion 3t and the piston P
Even if the posture is tilted, the skirt Ps is absorbed by the lower end of the tapered portion 3t before it passes through the lower end of the tapered portion 3t so that the posture can be corrected to the upright posture. Where the piston P
Is based on a position of the outer surface where the axial length becomes maximum.

In the case of the embodiment, the diameter of the piston P is φ81 and the inner diameter of the rough guide cylinder 6 is (φ81 + 0.0
5) to (φ81 + 0.1), the inner diameter of the inner diameter enlarged portion 6d is set to φ82.0 to φ82.5.

The piston insertion device 1 constructed as described above
In FIG. 4, as shown in FIG. 4, when the rough guide cylinder 6 moves to the set part of the chain line with the advance of the movable plate 5,
For example, the piston P is inserted and set in each of the rough guide cylinders 6 by an operator or the like. During this time, the guide cylinder 3 is fixed to the position of the cylinder hole Wh of the cylinder block W with its axis aligned.

When the piston P is inserted and set in the rough guide cylinder 6, the movable plate 5 is retracted, and each of the rough guide cylinders 6 is moved directly above each of the guide cylinders 3 so that their axes are aligned. After being connected as shown in FIG. 5, it is clamped.

Next, when the respective pushing members 8 descend by the lowering of the lifting / lowering bodies 7 and push the pistons P downward, the pistons P are pushed along the inside of the rough guide cylinders 6 and guide from the rough guide cylinders 6. The process moves to the cylinder 3. And the skirt portion Ps of the piston P is the tapered portion 3 of the guide cylinder 3.
t, the rough guide cylinder 6 and the guide cylinder 3
Even if the piston P is tilted due to the positional deviation, the tilt of the posture is corrected and returned to the upright posture at the time when the piston head enters the inner diameter enlarged portion 6d.

Therefore, when the skirt portion Ps of the piston P approaches the entrance of the cylindrical hole Wh, the piston P does not tilt and is smoothly pushed into the cylinder Wh.

Incidentally, the inner diameter enlarged portion 6d as described above is
Only a part of the existing rough guide cylinder 6 needs to be processed, and the existing equipment can be utilized to the full and simple and inexpensive.

The present invention is not limited to the above embodiment. Those having substantially the same configuration as those described in the claims of the present invention and exhibiting the same operation and effect belong to the technical scope of the present invention. For example, the number of cylinders of the engine is arbitrary, and the specific piston diameter is also arbitrary.

[0025]

As described above, in the piston insertion device according to the present invention, the guide cylinder having the tapered portion on the inner periphery is connected to the cylinder hole of the cylinder block, and the rough guide cylinder is connected to this guide cylinder to connect the piston. In a piston insertion device such as a push-in type, the rough guide cylinder is provided with an enlarged inner diameter part to absorb the inclination of the piston posture caused by the tapered part of the guide cylinder, so that the insertion device that can insert the piston smoothly can be simplified. Can be configured.

[Brief description of the drawings]

FIG. 1 is a side view of a piston insertion device according to the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is an enlarged view of FIG. 1;

FIG. 5 is a longitudinal sectional view of a rough guide cylinder and a guide cylinder.

6 is an enlarged view of a main part of FIG. 4;

FIG. 7 is an explanatory view showing a conventional procedure for aligning the axes of the guide cylinder and the cylinder hole of the cylinder block.

FIG. 8 is an explanatory view showing a state when a conventional piston is inserted.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Piston insertion device, 3 ... Guide cylinder, 3t ... Taper part, 6 ... Rough guide cylinder, 6d ... Inner diameter expansion part, 8 ... Pushing member, P ... Piston, W ... Cylinder block, Wh ... Cylindrical hole, h ... Piston Height, d: Length range of the inner diameter enlarged part, t
... The length range of the tapered part.

Claims (1)

[Claims] 1. A guide cylinder connected to an opening of a cylinder hole of a cylinder block, a rough guide cylinder connected to an upper end opening of the guide cylinder, and a piston set in the cylinder of the rough guide cylinder. A piston insertion device comprising a pushing member for pressing downward, and a tapered portion having an inner diameter expanding upward is formed on the inner surface near the upper end opening of the guide cylinder in a length range not exceeding the height of the piston. In addition, on the inner surface near the lower end opening of the rough guide cylinder, there is provided an enlarged inner diameter portion that absorbs the inclination of the attitude of the piston caused by the tapered portion. A piston insertion device, wherein the length of the piston insertion device is at least equal to the difference between the height of the piston and the length range of the tapered portion.