JPS5893906A - Lubricating device of eccentric bearing in variable compression ratio mechanism - Google Patents

Abstract

PURPOSE:To smoothly turn an eccentric bearing and improve its reliability and durability, by providing a different lubricating oil passage communicated to an oil passage for a slidable lock pin provided between a connecting rod and the eccentric bearing. CONSTITUTION:Under a condition in which an eccentric bearing 5 and connecting rod 4 are not fixed by a lock pin 7, a piston 1 is in a low compression state, reversely under a condition fixed with the both 5, 4 by the pin 7, the piston becomes a high compression state. In such a variable compression mechanism, lubricating oil passages 10, 11 are connected in the rod 4 in addition to a normally provided lock pin driving oil passage 8. That is, the passage 10 is communicated to a peripheral sliding part 12 of the bearing 5 from a throttle part 9 and the passage 11 is communicated to an internal peripheral sliding part 13 from the part 12. While a groove 14 is formed circumferentially along the periphery of the bearing 5 in a small-end of the rod 4, and this groove 14 is connected to an oil filler port 15.

Description

[Detailed Description of the Invention] The present invention provides an eccentric bearing between the connecting rod and the piston pin. The present invention relates to a variable compression ratio mechanism for an internal combustion engine that is capable of changing the compression ratio of the engine by interposing the variable compression ratio mechanism, and to a lubricating device for an eccentric bearing that is a component of the <Vcir variable compression transverse ratio mechanism.

In order to improve engine fuel efficiency, emissions, output performance, and low-flow startability, the VC pressure ratio should be lowered at full load, and the pressure Jilii ratio should be increased at partial load to improve operating conditions. It is effective to change the compression ratio accordingly.

For this purpose, a variable compression ratio mechanism was first developed in which an eccentric bearing is interposed between the connecting rod and the piston pin, and the relative position of the piston to the connecting rod is completely changed by the rotation of the eccentric bearing, and the pressure ratio is completely variable. Proposed.

However, Figure 1 is a representative example of the variable compression ratio mechanism proposed earlier (Japanese Patent Application No. 136298/1983).
A lock pin fixing chamber 3e is formed by connecting the connecting rod 1' and two eccentric bearings, and a lock pin 41 is slidably inserted into the lock bin fixing chamber 3, and the lock pin fixing chamber 31 is connected to a VC oil passage. 51 is connected, and by applying or releasing hydraulic pressure to the lock bin 4' through the oil passage 51, the rotation of the Jiii core bearing 2 is fixed or freed. The compression ratio is made variable.

In addition, Fig. 2 shows another typical example of the variable compression ratio mechanism previously proposed by VC (title of the patented invention ``Variable compression ratio mechanism for internal combustion engines'' filed on November 26, 1981). The two oil passages 5+ and 6+ are connected to the lock bin fixing chamber 31 in the previous example, and the lock pin 4■ can be driven hydraulically in both the vertical and vertical directions, and the drive of the lock pin 41 is driven only by inertial force. It is said to be more reliable.

The variable compression ratio operation is more reliable.

However, in the variable width ratio mechanism using an eccentric bearing as described above, Rf# of the eccentric bearing is (I
In both examples, the lubricant was supplied naturally from the 7° angle provided at the upper part of the small end of the connecting rod 1. In this case, if only this method is used for sliding, the oil level will be small, and the movement of the is-centered bearing 2I will become irregular, making it impossible to switch between high and low compression ratios, and in severe cases, the first-centered bearing 21 will burn out. There was a time when I was worried that it might stick.

The present invention aims to solve all of the above problems in variable compression ratio mechanisms using eccentric bearings.

Allows eccentric bearings to move smoothly and reliably.

Another object of the present invention is to provide a lubricating device for an eccentric bearing that can prevent seizing of the control bearing.

In order to achieve all of these objects, 1. In the lubricating device of the variable compression W mechanism of the present invention, a lock pin formed in the connecting rod, preferably has a cross-sectional area smaller than the passage cross-sectional area from a part of the oil passage for mb. A lubricating oil passage is provided with
V is connected and connected.

Through this oil bending distance, the sliding distance V on the inner and outer periphery of the steel core bearing
C group Qing? The mountain is guided and served.

By supplying oil through the VC line through the VC line, much smoother and more reliable lubrication is achieved than with conventional lubrication from only the small end upper end oil filler port.

A preferred embodiment of the present invention will be described below with reference to U=FIG. 1Tfl.

3 and 4 fully illustrate the first embodiment of the present invention. In the figure, 1 is a piston, 2 is a cylinder block, 3 is a piston pin, and 4 is a connecting rod. Between the piston pin 3 and the connecting rod 4, an eccentric bearing 5 made of an eccentric cylinder is interposed to rotate. ing.

There is a problem with the eccentric bearing 5 and the connecting rod 4.
A lock bin fixing chamber 6 is provided in the lock bin fixing chamber 6, and the lock bin fixing amount 6 V (the lock bin 7 is inserted into the sliding groove VC). Oil passage 8 runs from the big end to the small end, and 1
The mountain 11 circuit 8 is closed to the lock bottle fixing chamber 6. The upper part 9 of the oil passage 8 in contact with the lock bin fixing chamber 6 is constricted, and the lock bottle 7 is trapped inside the oil passage 8 by Vc. It is made sure that there is no such thing.

These oil passages 8.9 form oil passages for driving the lock bin 7.

Lock pin w1 ej in hydraulic oil passage, another oil passage 10゜1
1 is connected, and the core oil passage 18 communicates with the sliding portion 12.13 of the eccentric bearing 5. For example, the oil passage 10 extends from the constriction part 9 to the external sliding part 12 of the eccentric bearing 5, and the oil passage 11 extends from the outer peripheral sliding part 12 of the eccentric bearing 5.
It extends from s12 to the inner peripheral sliding portion 13. These oil passages 10.11 lead from the driving oil passages M8, 9 to the sliding portions 12.13 of the oil-driven bearing 5, and form groove oil passages. @ mm Oil channel 10, 11 Driving oil channel 8゜9 machining cross-section is 1". Drill oil with large needle from drive oil channel 8, 9. Oil channel 10.11 K flows and lock pin 76- The VC is designed so that you don't have to do both.

In addition, the small end VC1 of connecting rod 4
d A circumferential VC groove 14 is formed on the outer periphery of the eccentric bearing 5 , and this groove 14 is also connected to an oil inlet 15 .

Lower end of oil passage 8 (l-tl connecting rod 4
On the outer periphery of the crank pin 16 of the big end (1v
It is attached to the letter 17 for 1,000 yen, and this groove 17 is attached.

The oil passage 18 in the crankshaft allows two mutually independent +'+120.21 V'Ci holes formed along the outer periphery of the crank journal 19 in a semicircular shape. Two independent M2O and 21 are two main oil passages that are independent of q, respectively, formed within the cylinder block.

That is, it is connected to the high-pressure tsumugi ratio main passage 22 and the low-pressure sardine ratio main passage 22. Pressure oil is supplied under pressure from the oil pan via the oil pump.

Engine operation condition V (with attached switching valve VC, high compression ratio J
Either 11 main oil passage 22 or low pressure width ratio 711 main passage 23 is supplied tC. 24 is the oil spout to the piston 1, and 1 Ujikawa main passage device and oil passage 1.
Connection is possible via 8.

First, we will clarify the operation of the device according to the first embodiment.

First, when the +Jiii center bearing 5 is not fixed, the balance between the explosion pressure applied to the piston IK and the inertia force causes the piston 1 to operate as shown by the broken line in Figure 5, resulting in a low compression ratio state, and the eccentric bearing 5 is fixed. 5th
The cylinder operates as shown by the solid line in the figure to reach the cylinder compression ratio state. That is, the piston 1 is suspended by the two positions 41 of the commercial pressure ratio and the low compression ratio with respect to the connecting rod 4 due to the rotationally fixed or free VC of the eccentric bearing 5.

If it is desired to set the compression ratio to VCf4 as in the case of 6 partial load operation, switch the switching valve to the high pressure reduction main passage M22 side from t/C.

The pressure oil of ^ pressure is applied to the lock bin 7 through the oil passages m20, 18, 8.9', and the thick part of the eccentric bearing 5 comes to the bottom near the top point of transition from the exhaust stroke to the intake stroke VC. When the lock bin 7 enters the lock bin fixing chamber 6 of the 1lii center bearing 5, and the I of the 1 concentric bearing 5
11′! The first rotation is fixed and a state of quotient compression ratio is obtained.

In the cylinder pressure ratio state, the sliding parts of the i-, t, and tg center bearings 5 become the sliding surfaces of the piston pin 3 and the inner peripheral surface of the eccentric bearing 5, but in this case, the oil passages 10, ] 1 are As shown in Fig. 3, since it has a rectangular shape, oil is supplied to the surface of the Ti# movement on the inner peripheral side, and sufficient lubrication is achieved.

In addition, when it is desired to achieve a low pressure 7-fold ratio state such as during full load operation, the pressure of the pressure oil is applied to the main passage for low compression ratio by switching the 2-way switching valve, and the oil is Exit 24
7J), the lock bin 717]-1: No pressure is applied, the lock bin 7Fi is pulled out from the lock bin fixing chamber 6 formed on the eccentric bearing 5 side by inertial force, and the eccentric bearing 5 is free to rotate. , the piston 1 is designed to have the number C shown in FIG. 5, and the low compression ratio state shown in FIG. 4 is obtained. In this case, the sliding part of the pivot bearing 5 is the inner and outer circumference of the eccentric bearing 5.

After cooling the piston 1, oil #l is applied from the oil inlet 15 to the inner wall of the piston 1 (C).
14 Vr- is entered, the entire outer circumference of the eccentric bearing 5 is lubricated, and the inner circumference of the eccentric bearing 5 is further lubricated through the oil passage 11 and the hole in the lock bin fixing chamber 6.

This allows eccentric bearing 5! 1lTII Kiha I'S
It becomes clear and certain.

6 and 7 show a second embodiment of the invention. In this actual example, the lubricating oil passage is inside the lock bin itself in the pitcher direction V? :M except that the operation is the same as in the first embodiment, and the same reference numerals as in FIGS. 3 and 4 are given to the parts that are similar to the first embodiment.

In the second embodiment, 5 is an eccentric bearing, 6 is a lock bin fixing chamber, 7 is a lock pin, and the through hole inside the lock pin 7 constitutes @ Namegawa oil passage 25, and the oil passage 10 of the first embodiment. It corresponds to the sum of 11.

Next is the 2nd one @? ! The operation in I will be explained and explained.

The lubrication of the eccentric bearing 5 in the compression ratio state is shown in Figure 6. Oil supplied to the oil groove 17 to maintain a high compression ratio is passed through the oil passage 8 to the lock pin fixing chamber 6.
and pushes the lock bin 7 into the lock bin fixing chamber 6 of the eccentric bearing 5.

Identify the rotation of the eccentric bearing 5. The excess Yuzu in the box is sent to IJf+ via the @ Namegawa oil passage 25 inside the lock pin 7.
It is used to lubricate the inner sliding surface of the single core bearing 5. Here, an oil groove may be provided on the inner surface of the eccentric bearing 5 or the outer surface of the piston pin 3 to further promote sliding, or the oil groove and the oil groove 14 may be combined to cool the piston through the oil supply port 15'fr.

Although FIG. 7 shows the case of a low compression ratio, the oil spout 24
After cooling the piston, the oil slides on the eccentric bearing 5 through the oil inlet 15y.

8 and 9 show a third embodiment of the invention. In this embodiment, an oil passage for driving the lock bin 7 is provided in the connecting rod 4 [2 systems 8.26, and the shape of the lock bin 7 is equipped with a 7 flange 7a in order to receive pressure from above to below. There is. In the lock bin fixing chamber 6, a portion 27 corresponding to the upper part of the flange 7a functions as an operating chamber for releasing the fixation of the lock bin.
9 I am doing it. The lubricating oil passages 10° and 11° communicate with oil passages 26. 28 is an oil groove for high compression ratio provided in the crank pin bearing, and 29 is an oil groove for low compression ratio, which are independent from each other and connected to oil passages 8 and 26, respectively.

The oil grooves 28 and 29 are connected to the crank journal 11%1 through the oil passage 18 provided in the crankshaft, respectively.
It can be connected to the oil grooves 20 and 21 of the first receiver, and furthermore, the main passage 22 for high compression ratio. Main connection for compression ratio to jl w12
Connect to 3.

Pressure oil can be switched to both main passages 22, 23 using a switching valve according to the operating conditions of the engine.

Other configurations are similar to those in the first embodiment, so similar parts are given the same reference numerals as in FIGS. 3 and 4.

The operation of the third actual relaxation example is as shown in Tsusa'. That is, at the time of 1 partial load, the switching valve switches to the side that applies hydraulic pressure to the high compression ratio main passage 22, and the pressure oil is transferred to the oil passage 18. A portion of the oil flows from the oil jet 1-124 through the oil surface 28 to the piston 1.
It is scattered onto the surface, and the rest enters the lock bin fixing chamber 6Vc via the oil passage 8.

The lock bin 7 is driven and pushed into the lock bin fixing chamber 6 in the tubular bearing 5, and the eccentric bearing 5 is fixed in a high compression ratio state as shown in FIG.

? After the oil ejected from the '8J spout 24 cools the piston l, a part of it enters the hydraulic pressure input 1:llll 15, t
l = Outer periphery I of center bearing outer periphery 5 Enters #14 and outer periphery sliding I
J[lI to lubricate the body.

Also, when the VC is at full load, the switching valve is the main 1 for low compression ratio [! 1
Road 23111d K cut bamboo, pressure oil is oil sho 21. Oil passage 1
8. Push the lock bin 7 completely downwards through the oil passage 26. As shown in FIG. 9, the rotation of the eccentric bearing 5 is released. This results in a low compression ratio condition. In this case, the excess oil in the oil passage 26 is supplied to the outer periphery of the control bearing 5 through the decoy oil passage 10, and is further supplied to the oil passage 1] and the eccentric bearing 5 through the oil passage 14'. A portion of the inner circumferential sliding portion 13 of the eccentric bearing 5 is also supplied through the hole in the lock pin fixing chamber. This lubricates the eccentric bearing 5.

As described above, the eccentric bearing lubrication device W of the variable compression ratio mechanism of the present invention further includes a lubricating oil passage in the oil passage for driving the lock pin.

Since the sliding parts on the inner and outer peripheries of the eccentric bearing are lubricated, according to the present invention, regular movement of the single-center bearing can be obtained, and seizing of the eccentric bearing can also be prevented. As a result, reliability and durability are excellent. A variable compression ratio mechanism can be used.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the operating system Wc of the previously proposed variable compression ratio mechanism. FIG. 2 is a sectional view showing an operating system R of a variable compression ratio mechanism according to another example previously proposed. FIG. 3 is a sectional view showing the operating system of the variable compression ratio mechanism according to the first embodiment of the present invention in a state where the eccentric bearing is fixed in rotation. Figure 4 shows the cross section of the mechanism shown in Figure 3 in the eccentric bearing rotation = 14 - free state. @Figure 5 is a diagram of the operating state of the piston. FIG. 6 is a sectional view showing the operating system of the variable compression ratio mechanism according to the silk 2 practical example of the present invention in a state where the 1wl center bearing is rotationally fixed. Figure 7 is a side view of the eccentric bearing of the mechanism shown in Figure 6 in a free state of rotation. Figure 8 is a cross section of the eccentric bearing in a fixed state of rotation showing the operating system of the variable compression ratio mechanism according to the @3 embodiment of the present invention. Fig. 9 is a sectional view of the mechanism shown in Fig. 8 with the eccentric bearing free to rotate. Eccentric bearing. 60.◆, Lock pin fixing chamber. 7...Lock bin. 8.26...Oil passage for lock bin drive. 10.11.25...Lubricating oil passage. 15...-・Oil inlet. 24...Oil spout. Patent applicant Toyota Motor Corporation Agent Patent attorney 1) Tsune Fuchi Figure 6 Figure 7 Figure 8 Figure 7 Figure 9

Claims (1)

[Claims] (1) The eccentric bearing is completely interposed between the connecting rod and the piston pin, and the connecting rod and the eccentric bearing are wrapped around each other to form a lock pin fixing chamber, so that the lock pin can freely slide into the lock pin warming/fixing chamber. Connect the oil passage for driving the lock pin to the fixation chamber of the lock bin, and apply hydraulic pressure to the lock pin through the oil passage.
In the variable compression ratio mechanism that operates the lock pin to change the compression ratio of the engine, the oil passage for driving the lock pin is provided with another oil passage for lubrication that communicates with the oil passage,
An eccentric bearing lubrication device for a variable compression ratio mechanism, characterized in that the oil passage for lubrication faces the sliding part of the eccentric bearing.