JPH082449Y2 - Piston insertion jig for integrated cylinder block - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention inserts a piston into an integrated cylinder block of an internal combustion engine in which a cylinder part having a cylinder bore and a head part defining a combustion chamber are integrally cast. The present invention relates to a piston inserting jig for a cylinder block for integrated type.

2. Description of the Related Art A main body of an internal combustion engine for an automobile is generally divided into a cylinder block and a cylinder head along an upper end of a cylinder and cast, and the two are bolted together through a cylinder head gasket. Has become.

In this configuration, the piston is incorporated into the cylinder bore from the upper end side of the cylinder bore with the cylinder head removed.

That is, as shown in FIG. 7, the piston ring 33 of the piston 32 connected to the connecting rod 31 is compressed in the radial direction by a cylindrical jig, a so-called ring compressor 34. Skirt part
35 is inserted into the cylinder bore 37 of the cylinder block 36 from the upper end side. At this time, since the skirt portion 35 is sufficiently long, it functions as a kind of guide, and the piston 32 and the cylinder bore 37 are maintained in a substantially perfect coaxial state. Therefore, if the top surface of the piston 32 is hammered in with a hammer or the like, the entire piston 32 is smoothly inserted into the cylinder bore 37.

On the other hand, in recent years, for example, Japanese Utility Model Laid-Open No. 62-69045 and Japanese Utility Model Laid-Open No. 62-69046 disclose an integrated cylinder block in which a cylinder portion and a head portion are integrally cast. In this integrated cylinder block,
There are advantages that the risk of leakage of cooling water and combustion gas at the cylinder head gasket portion is completely eliminated, and that the flow of cooling water around the combustion chamber is improved and the cooling performance is improved.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the integral type cylinder block integrally cast in such a state that the upper end of the cylinder bore is sealed by the head portion, as a matter of course, the piston 32 is incorporated as shown in FIG. It must be done from the lower end side of the cylinder bore 37.

In this case, the top land 38 at the upper end of the piston 32 is inserted as a guide, but the top land 38
The vertical width is very short compared to the skirt portion 35, and it is difficult to keep the posture of the piston 32 correctly. Moreover, when hitting with a hammer, the lower end of the unstable connecting rod 31 is hit.

Therefore, it is easily pushed in a bent state with respect to the cylinder axis, workability is poor, and the piston land and piston ring may be damaged.

Therefore, the present invention provides an integrated cylinder block in which the connecting rod has to be tapped from the lower end in order to insert the piston from the lower side of the cylinder bore.
It was decided to improve workability and reliability by holding the connecting rod at the approximate center of the piston and stabilizing it. That is, the structure adopted by the piston insertion jig for an integrated cylinder block according to the present invention is an integrated cylinder of an internal combustion engine in which a cylinder part having a cylinder bore and a head part defining a combustion chamber are integrally cast. A piston inserting jig for a cylinder block, which inserts a piston into a block, comprising a pair of clamps each formed in a semi-cylindrical shape and fitted onto the piston, and opening and closing the pair of clamps in a radial direction. A connecting member that connects as much as possible, a semicircular bottom wall that is provided at the bottom of each of the clamps, and a substantially central portion of each of these bottom walls that is cut out, and a connecting rod that is substantially at the axial center of the piston. It is characterized in that it is configured with a notch portion for holding.

Action When assembling the piston, the pair of semi-cylindrical clamps connected by the connecting member are opened in the radial direction, the pistons are accommodated in these semi-cylindrical clamps, and then the semi-cylindrical clamps are closed in the radial direction. As a result, the piston is fitted into each of the semi-cylindrical clamps, the piston ring is compressed in the radial direction, and the connecting rod connected to the piston is inserted into the cutout portion to be substantially in the axial center of the piston. Is held in position along. Next, the insertion jig holding the piston in this way is applied to the lower end of the cylinder bore, and the lower end side of the connecting rod is hit and pushed in, whereby the piston is inserted from the lower end of the cylinder bore.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an integrated cylinder block 1 in which the piston insertion jig for integrated cylinder block according to the present invention is used.
FIG. 3 is a cross-sectional view showing the overall configuration of

The cylinder block 1 is formed by integrally casting a cylinder portion 3 in which a large number of cylinder bores 2 are arranged in a row, and a head portion 4 located above the cylinder portion 3 and defining a combustion chamber. The skirt portion 5 and the bulkhead 6 are integrally formed in the lower portion of the cylinder portion 3, and the intake port 7, the exhaust port 8, the cam bracket 9 and the like are formed on the head portion 4 side. . still,
A main bearing portion 10 and a bearing cap 11 are fastened to the bulkhead 6 with a pair of cap bolts 12, and the piston is removed in a state where they are removed.
30 (see FIG. 2) is inserted.

Further, in the cylinder portion 3, a water jacket wall 14 is formed so as to surround the outer side of a cylinder wall 13 having a cylindrical shape, and a water jacket 15 is formed between the two. A water jacket 16 is formed in the head portion 4 as a core so as to surround the combustion chamber, the exhaust port 8 and the like. This head part 4
The side water jacket 16 communicates with the water jacket 15 on the cylinder portion 3 side in a wide range without being restricted by the cylinder head gasket.

On the other hand, on the lower surface of the lower deck 17, more specifically, on the periphery of the lower end of the cylinder bore 2, as shown in detail in FIG. 2, a fitting portion 19 capable of fitting with the end of the piston insertion jig 18 is provided as a recess. ing. The fitting portion 19 is one in which the lower end peripheral edge of the cylinder bore 2 is recessed, and has a side wall surface 19a parallel to the cylinder axis. The fitting portion 19 is formed in an elliptical shape with a short diameter in the crankshaft direction in order to avoid interference with an adjacent cylinder.

Piston insertion jig 18 fitted in the fitting portion 19
Is, for example, as shown in FIG. 3 and FIG. 4, a pair of semi-cylindrical clamps 20 is connected with a hinge 21 so as to be openable and closable,
In addition, a locking piece 22 and a lock pin 23 are provided on the side opposite to the hinge 21. Here, the hinge 21, the locking piece 22, and the lock pin 23 constitute a connecting member. In addition, the bottom of each clamp 20 has a semicircular bottom wall 24
Are provided respectively, and a rectangular notch 26 for positioning the connecting rod 25 extending from the piston 30 at substantially the same position as the axial center of the piston 30 is formed in the substantially central portion of the bottom wall 24. ing. Further, a relatively thick elliptical flange portion 27 capable of fitting relatively tightly with the fitting portion 19 is provided on the upper end portion of the insertion jig 18.

Next, a procedure for incorporating the piston 30 into the cylinder bore 2 in the above configuration will be described.

First, the piston 30 fitted with the piston ring 28 is fitted into the piston insertion jig 18 to lock the locking piece 22. That is, the piston ring 28 is compressed to the same diameter as the piston 30. In this state, the piston ring 28
Are all housed in the piston insertion jig 18, and the top land portion 29 is slightly projected from the tip of the jig 18.

Next, in this state, the flange part of the piston insertion jig 18
The 27 is fitted into the fitting portion 19 of the cylinder block 1. As a result, the inner peripheral surface of the piston insertion jig 18 and the cylinder bore 2
The inner peripheral surface is completely continuous. That is, the cylinder bore 2 and the piston 30 are reliably kept in the coaxial state.
At the same time, the connecting rod 25 is held in a position along the axial center of the piston 30 because the connecting rod 25 is fitted in the cutout portion 26. Then, when the lower end of the connecting rod 25 is hit with a hammer or the like, the piston 30 is smoothly inserted into the cylinder bore 2.

Therefore, according to the present embodiment, the notches 26 are provided in the bottom walls 24 of the pair of clamps 20 which are openably and closably coupled, and the notches 26
Since the connecting rod 25 is inserted through the connecting rod 25 to hold the connecting rod 25 at the substantially axial position of the piston 30, workability is improved and the piston land of the piston 30 and the piston ring 28 are not damaged. Can be prevented.

That is, even if the piston 30 itself is coaxial with the cylinder bore 2, if the connecting rod 25 is slanted and is not positioned substantially coaxially with the piston 30, when the connecting rod 25 is hit and pushed, The radial component of the pushing force acting on the piston 30
Join. Therefore, in this case, the piston 30 is pressed against the cylinder bore 2 and "twisting" or the like occurs in the top land portion 29 or the like, or an unnecessary impact is applied to the pin boss portion connecting the connecting rod 25 and the piston 30. The sliding surface may be roughened. On the other hand, in the present embodiment, the connecting rod 25 can be positioned substantially at the axial center of the piston 30, so that the insertion work can be easily performed while protecting the piston 30.

In the above embodiment, the fitting portion 19 and the flange portion 27
Is oval, but if there is enough space between the cylinders,
Of course, it may be a perfect circle.

Next, the embodiment shown in FIG. 5 is an example in which a fitting portion 19 having a relatively narrow radial width is provided in the peripheral edge of the lower end of the cylinder bore 2. In this case, a relatively thin-walled cylindrical tool is used as the piston insertion jig 18.

In the embodiment shown in FIG. 6, the lower end of the cylinder bore 2 is
A fitting portion 19 extended in a cylindrical shape is provided, and a large diameter portion 18a of an end portion of a piston insertion jig 18 is provided on an outer peripheral surface 19b thereof.
Are designed to fit together.

Effect of the Invention As described in detail above, according to the piston inserting jig for an integrated cylinder block according to the present invention, a connecting rod is formed on the bottom wall of a pair of semi-cylindrical clamps that can be opened and closed. Since the notch portion for holding the piston at the axial center position is provided, it is possible to easily insert the piston while assembling the piston while preventing the ring land portion of the piston from being damaged.

[Brief description of drawings]

FIG. 1 is a sectional view of the entire integrated cylinder block in which the piston inserting jig according to the present invention is used, FIG. 2 is an enlarged sectional view of the essential portion thereof, and FIG. 3 is a plan view of the piston inserting jig.
FIG. 4 is a side view of the same, FIGS. 5 and 6 are enlarged cross-sectional views of a main part showing a different embodiment of the present invention, and FIG. FIG. 8 is a sectional view showing a state in which the piston is inserted into the conventional integrated cylinder block from the lower end side of the cylinder bore. 1 ... Integrated cylinder block, 2 ... Cylinder bore, 3 ...
Cylinder part, 4 ... Head part, 18 ... Integral cylinder block piston insertion jig, 19 ... Fitting part, 20 ... Clamp, 21
… Hinge (connecting member), 22… Locking piece, 23… Lock pin,
24 ... Bottom wall, 25 ... Connecting rod, 26 ... Notch, 30
…piston.

Claims (1)

[Scope of utility model registration request] 1. A piston insertion jig for an integrated cylinder block for inserting a piston into an integrated cylinder block of an internal combustion engine, wherein a cylinder part having a cylinder bore and a head part defining a combustion chamber are integrally cast. And a pair of clamps each formed in a semi-cylindrical shape and fitted on the piston, a connecting member that connects the pair of clamps so as to be openable and closable in the radial direction, and provided on the bottom of each clamp. And a semicircular bottom wall, and a cutout portion that is provided by cutting out a substantially central portion of each of the bottom walls and that holds the connecting rod at a substantially axial center of the piston. Piston insertion jig for blocks.