JPS608408A - Oil supply structure for backside of piston - Google Patents

Abstract

PURPOSE:To aim at stabilizing the feed of oil to journals, by forming a lubrication oil passage in a position on the side of a crankshaft remote from a piston, and as well by disposing a directive nozzle on the backside of the piston to simplify the manufacturing and as well to prevent excessive oil from being fed to the backside of the piston. CONSTITUTION:Lubrication oil which has been fed from an oil pump into a main gallery 16, flows through an oil passage 17 for lubricating the journal 13a of a crankshaft 13 and the large diameter end part 14a of a connecting rod 14, and as well, the oil is jetted from a nozzle 22 to the backside of a piston 11 to cool the latter. The injection is intermittently carried out in association with the rotation of the crankshaft 13, and therefore, the lubrication oil is interrupted by the large diameter end part 14a of the connecting rod 14 in the vicinity of the top dead center before thereof so that the lubrication is made in only the period from the top dead center to the bottom dead center, thereby no exceesive oil is sprayed onto the cylinder wall surfacce so that wasteful consumption may be reduced. Further, since the oil is injected from a positon remote from the journals 13a, no substantial affection is made by the oil feed pressure of the journal 13a, and the oil feed pressure is therefore stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for supplying oil to the back side of a piston for injecting lubricating oil to the back side of the piston in a μ cycle engine.

Engine pistons are subjected to large loads both thermally and mechanically, but as the engine output increases and speeds increase, this load also increases, and due to the thermal and mechanical loads, piston land erosion and Since the piston-ring flange link is approaching its limit, efforts are being made to reduce the piston ring. As shown in Fig. 1, the conventional oil supply structure for the back side of the piston is such that a nozzle 2b directed toward the back side of the piston 3 is installed in the bearing pedestal 28 of the crankcase 2 that supports the crankshaft l. For nozzle installation, the jet nozzle 4 is installed in the hole 2bK, and the journal 1a of the crankshaft 1 is connected to the lubricating oil passage 5 that communicates with the main gear rally (not shown).
The oil supplied to the journal IaK is guided to the groove 2C provided in contact with the outer peripheral surface of the metal bushing 6 that fits into the journal IaK,
The jet nozzle 4 sprayed the liquid onto the back side of the piston 3. Although this conventional oil supply structure effectively utilizes the oil supply structure to the metal bush 6, mounting the nozzle increases the number of man-hours for machining the hole 2b, which increases cost.

Further, oil is always injected from this jet nozzle 4 to the back side of the piston, but it is easy to over-inject the oil and waste the oil. In addition, since the nozzle 4 is located at the end of the lubricating oil supply to the journal 1a, it is difficult to secure oil supply pressure to the journal la.This invention was made to solve the above-mentioned conventional drawbacks, and is easy to process and inexpensive. The purpose of the present invention is to provide a structure for supplying oil to the back side of the piston, which can prevent excessive oil supply to the back side of the piston, and stabilize the oil supply pressure to the journal of the crankshaft.

An embodiment of the present invention will be described below with reference to the drawings.

Figure 2 is a cross section of the main part of a beam cycle engine, Figure 3 is a cross section of the main part of a beam cycle engine.
The figure shows a cross section of the main parts of the TU-MS, and 10 is a cylinder, 11 is a piston, 12 is a crankcase, 13 is a crankshaft, and 14 is a connecting rod. The crankshaft 13 is rotatably supported by a bearing pedestal 12a of the crankcase 12 via a metal bushing 15.

At a position opposite to the piston 11 across the crankshaft 13, a main gear lary 16 serving as a lubricating oil passage is provided parallel to the crankshaft 13. This main gear rally 16 is not located at the exact opposite position to the piston 11,
As shown in FIG. 2, they are located offset from the exact opposite position. The bearing stand portion 12aK is connected to the main gear rally 16.
An oil passage 17 is opened for the lubricating oil to pass through the oil pump 1.
8, the oil flows through the υ oil passage 19 as shown by the arrow, and the oil filter 2
The oil is sent to the main gear rally 16 through the oil passage 17, and is supplied to the metal bushing 15 through the oil passage 17, where it lubricates the journal 13a of the crankshaft 13. In addition, a lubricating oil hole 13b is drilled in the crankshaft 13, and a connecting rod 14
The needle bearing 21 at the large end 14 & of the needle bearing 21 is also lubricated by the lubricating oil from the oil passage 17.

A jet nozzle 22 directed toward the back side of the piston 11 is provided at a position facing the front main gear rally 16Ktj: and the crank bin 13cK, that is, at an intermediate position between the left and right crank webs 13d. This nozzle 22 has a large diameter hole 22a1 on the inlet side and an outlet side, and a small diameter hole 22b in the middle part, as shown enlarged in FIGS. 4(a) and 4(b).
Holding #22c on the top end surface, it is screwed into the 9-digit hole 16aK into the main gear lary 16.

In addition, the engine in the example is a multi-fi # parallel engine,
Although not shown, nozzles 22 are provided at positions corresponding to each piston of the main gear rally 16.

'f*, 23 is an alternator provided at the end of the crankshaft 13, 24 is a cam chain, and 25 is a tube for sending lubricating oil to an oil cooler (not shown). The oil pump 18 supplies lubricating oil to the transmission, camshaft, and various parts of the engine, although the details are omitted.

Next, to explain the operation, the lubricating oil sent to the main gallery 16 by the oil pump 1B passes through the oil passage 17 and lubricates the journal 13a1 of the crankshaft 13 and the large end 14a of the connecting rod 14.
Piston 1 from nozzle 22 provided on main gear rally 16
1 and cools the piston 11. This injection occurs as the crankshaft rotates 130 times (in the direction of arrow (A) in FIG. This is an intermittent injection that is performed only after υ and towards the bottom dead center. Therefore, the lubricating oil is not excessively sprayed on the cylinder wall surface, and unnecessary consumption of lubricating oil due to oil rising is reduced. In addition, the lubricating oil after lubricating the journal 13aK is not injected, but is injected from a different position separated by light from the journal 13a.
The oil supply pressure in a is less affected and stabilized.

Note that the nozzle 22 is not limited to the jet nozzle as in the embodiment, but may be one in which a small hole is simply made in the main gear rally 16.

In addition, from the standpoint of cooling the piston 11 and preventing unnecessary consumption of lubricating oil, in order to perform intermittent injection most appropriately, the amount of positional deviation of the main gear lary 16 (i.e., the deviation from the opposite position of the piston 11) distance).

As explained above, in the present invention, an MK lubricating oil passage is provided on the opposite side of the piston across the crankshaft, and a nozzle directed toward the back side of the piston is provided in this lubricating oil passage. The mounting structure is significantly simpler than conventional ones, requiring fewer processing steps and reducing costs. In addition, since the injection of lubricating oil to the back side of the piston is interrupted by the large end of the compound and is performed intermittently, there is no excessive injection of lubricating oil, and unnecessary consumption of lubricating oil can be prevented. Furthermore, the oil supply pressure to the crankshaft journal is stabilized.

[Brief explanation of drawings]

Fig. 7 is a sectional view of a wall of an l-cycle engine showing a conventional oil supply structure to the back side of a piston, and Fig. 2 and the following show an embodiment of the present invention. Figure 3 is a sectional view of the main part at mm in Figure 2,
The mark in Fig. 3 is a sectional view taken along the mV-IV line in Fig. 3.
) is a view in the direction of arrow A of P) in the same figure. lO...Cylinder, 11...Piston, 12...Crankcase, 13...
Crankshaft, 15...Metal bushing,
16... Main gear rally (lubricating oil passage), 17
．． 19...Oil path, 18...Oil pump, 22...Jet nozzle.

Claims (1)

[Claims] A structure for supplying oil to the back side of a piston in a cycle engine, characterized in that a lubricating oil passage is provided at a position opposite to the piston, sandwiching the crankshaft, and a nozzle directed toward the back side of the piston is provided in the lubricating oil passage.