JPH05231418A - Lubricating oil passage construction for connecting rod - Google Patents

Abstract

PURPOSE:To enable the capacity of an oil pump to be reduced by providing an inertia detection valve at an oil passage formed in a connecting rod for introducing lube oil fed through a crankshaft from the large diameter end section of the rod to the small diameter end section thereof, and feeding lube oil only when an engine is running at high speed. CONSTITUTION:An internal combustion engine causes a crankshaft to rotate by transmitting the reciprocating motion of a piston 4 to a crankshaft 5 via a connecting rod 1. This connecting rod 1 is internally provided with a small bore oil passage 18 for introducing lubricating oil fed through the oil port 17 of the crankshaft 5 from a large diameter end section 3 to a small diameter end section 2. In addition, an inertia detection valve 27 is provided at the end of the large diameter end section of the oil passage 18. The valve 27 is made of iron and constituted of a mass body 25 having a spherical form and a coil spring 26. When an engine speed exceeds the predetermined level, the coil spring 26 is compressed with an inertia force acting on the mass body 25, and a valve seat 30 is released, thereby allowing the feed of lube oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure in which a lubricating oil passage structure for cooling the rear surface of a piston is provided in a connecting rod.

[0002]

2. Description of the Related Art Conventionally, for the purpose of cooling a piston, as shown in FIG. 5, a lubricating oil supplied from a crankshaft 71 is passed through an oil passage 73 formed in a connecting rod 72 and an injection hole 75 of a small end 74 is formed. There is known a lubricating oil passage of a connecting rod in which lubricating oil is injected toward the piston back surface 76 from here (see Japanese Utility Model Laid-Open No. 58-106612).

[0003]

By the way, the temperature of the piston 70 becomes high enough to require cooling at the time of high rotation, and at the time of low rotation, the heat generation amount per unit time is small. Does not require much cooling.

On the other hand, through the oil passage 73, the piston rear surface 7
The oil pump that discharges the lubricating oil sufficient to lubricate the entire engine, including the lubricating oil injected in No. 6, is driven by the power of the engine. The oil pump has a low discharge capacity, that is, an oil pump having a discharge capacity sufficient to sufficiently lubricate the entire engine at low rotation speed with low discharge capacity is required.

However, in the conventional lubricating oil passage structure as described above, since the lubricating oil is always supplied to the rear surface of the piston regardless of the operating state of the engine, the piston 70 is Even at low revolutions when it is not necessary to cool it, a part of the lubricating oil discharged by the oil pump flows out from the injection holes 75, that is, even at low revolutions when the discharge capacity of the oil pump is low. Since a part of the lubricating oil discharged by the oil pump has been consumed unnecessarily, an excessively large capacity oil pump is required, and the output loss for driving this large capacity oil pump increases. , There was a problem.

The present invention has been made in view of such conventional problems, and provides a lubricating oil passage structure for a connecting rod capable of supplying lubricating oil toward the rear surface of the piston only at the time of high rotation.

[0007]

In order to solve the above-mentioned problems, the present invention provides a connecting rod having a small end connected to a piston at one end and a large end connected to a crankshaft at the other end. An oil passage that is formed in the connecting rod and that guides the lubricating oil supplied from the crankshaft from the large end portion to the small end portion; and an injection passage that communicates with the oil passage and that faces the piston rear surface and opens to the small end portion. In the lubricating oil passage structure of the connecting rod having a hole,
When a mass body that opens and closes the oil passage and an elastic body that biases the mass body in a direction to close the oil passage are formed in the oil passage, and an inertial force exceeding a predetermined amount acts on the mass body. A lubricating oil passage structure for a connecting rod, further comprising an inertial force detection valve for opening the oil passage against the biasing force of the elastic body.

[0008]

According to the above construction, the inertial force detection valve provided in the connecting rod opens / closes the oil passage by detecting the inertial force in the reciprocating direction of the piston. That is, when the operating state of the engine exceeds a predetermined rotation speed, an inertial force exceeding a predetermined amount acts on the mass body, and the mass body opens the oil passage against the biasing force of the elastic body. Then, when the operating state of the engine falls below a predetermined rotation speed, the biasing force of the elastic body overcomes the inertial force acting on the mass body to close the oil passage.

As a result, the lubricating oil can be supplied to the back surface of the piston only at the time of high rotation where cooling of the piston is required, so that the consumption amount of the lubricating oil at the time of low rotation where the discharge capacity of the oil pump is low is reduced, Even an oil pump with a small capacity can sufficiently cover the entire engine, and the power loss for operating the oil pump can be reduced accordingly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 is a small end 2 at one end and a large end 3 at the other end
Is a connecting rod having a small end 2 connected to a piston 4 and a large end 3 connected to a crankshaft 5. It is the piston pin 6 that connects the small end 2 and the piston 4, and a metal 7 is inserted between the small end 2 and the piston pin 6, and there is a gap between the metal 7 and the piston pin 6. Are fitted together. An oil groove 9 is engraved on the outer peripheral surface 8 of the metal 7 over the entire circumference in the central portion thereof, and an annular oil passage 10 is formed between the metal 7 and the small end portion 2.

The connecting rod cap 11 constituting the large end portion 3 is fastened to the main body of the connecting rod 1 with two cap bolts 12, thereby connecting the crankpin 13 of the crankshaft 5 to each other. And
A half-divided bearing metal 14 is interposed between the large end portion 3 and the crank pin 13, and a sliding surface 15 of the bearing metal 14 is provided with an oil groove 16 in the central portion thereof over the entire circumference.

An oil hole 17 communicating with an oil gallery in a cylinder block (not shown) is formed in the crank pin 13 so as to face the oil groove 16. That is, a part of the lubricating oil flowing in the oil gallery formed in the cylinder block (not shown) is supplied to the sliding surface of the main bearing (not shown) that supports the crankshaft 5, and the lubricating oil supplied to the sliding surface is supplied. The oil is supplied to the oil hole 17 provided in the crank journal (not shown). Then, the oil reaches the oil groove 16 through an oil hole 17 formed in the crankshaft and is guided to an oil passage 18 described later.

A fine oil passage 18 is formed in the connecting rod 1 to guide the lubricating oil supplied from the crankshaft 5, that is, the oil hole 17, from the large end portion 3 to the small end portion 2. .. The end 19 on the large end side of the oil passage 18 passes through a hole 20 formed in the bearing metal 14 and passes through the oil groove 1
6, the small end side end 21 passes through the oil passage 9 and the injection hole 2
Connect to 2. Then, the injection hole 22 formed in the small end portion 2
Is opened toward the piston back surface 23, and is provided on the connecting rod axis L.

At the end 19 of the oil passage 18 on the large end side, an inertial force detection valve 27 is provided which is composed of a spherical mass body 25 made of iron and a coil spring 26 (elastic body). As shown in an enlarged manner in FIG. 2, a valve chamber 28 having a diameter larger than that of the oil passage 18 is formed at the end 19 of the oil passage 18 on the large diameter portion side. The coil spring 26 is housed on the side of the hollow body 2 and the mass body 25 is housed on the side of the large end 3 thereof.
The valve seat 30 having 9 is press-fitted and fixed so as to contract the coil spring 26, and the oil passage 18 is kept closed.

The oil passage 18 is opened so that the operating condition of the engine exceeds a predetermined number of revolutions, that is, the oil passage 18 is opened when an inertial force exceeding a predetermined amount acts on the mass body 25. Thus, the mass of the mass body 25 and the spring constant of the coil spring 26 are set.

However, the predetermined rotation speed is set to the rotation speed at which cooling of the piston 4 should be started, and in this embodiment, the oil passage 18 is opened when the rotation speed reaches 3000 rpm, which is lower than the maximum output (torque) point of the engine. As described above, the inertial force detection valve 27 is set.

Explaining the setting method concretely, the inertial force F _I acting on the mass body 25 is

[0018]

[Equation 1]

However, m: mass of mass body r: radius of rotation of crankpin L: load length (distance between small end and large end) λc: epilepsy ratio (λc = L / r) ω: angular velocity θ It is represented by: Crank angle N: Number of rotations (rpm), and when θ = 0 (rad), the inertial force F _I becomes maximum. Therefore, the inertial force F _I (max) at this time is

[0020]

[Equation 2]

It is represented by In addition to this, as a general value r
= 0.039 (m) and λc = 3.3 are substituted,
F _I (max) assuming that the mass of the mass body 25 is 1 × 10 ⁻³ (Kg)
When the engine speed N is 3000 rpm, F _I (max) = 0.5 (kgf) and when the engine speed N is 5000 rpm, F _I (max) = 1.4 (kgf).

On the other hand, regarding the spring constant K of the coil spring, the lateral elastic modulus G of the wire is 8 × 10 ³ (kgf / m
m ² ), the wire diameter d is 0.3 (mm), the coil diameter D is 2 (mm), and the number of turns N is 10,

[0023]

[Equation 3]

It is represented by

Therefore, when the mass 25 is seated on the valve seat 30, the coil spring 26 is set to 5 m from its natural length.
When set by reducing by m, the engine speed is 3000 rp
When it exceeds m, the oil passage 18 is opened as shown in FIG.
For example, when the engine speed reaches 5000 rpm,
Since the coil spring 26 contracts from its natural length to a maximum of 14 mm, the oil passage 18 is fully opened during the downward movement of the piston.

It should be noted that the coil spring 26 contracts to the maximum at the normal maximum rotation speed of the engine, but at this time, a gap is left between the wires forming the coil spring 26, that is, the coil. It is considered that the flow path of the lubricating oil is ensured in the gap between the wires forming the coil spring 26 when the spring 26 is contracted to the maximum.

Next, the operation will be described based on such a configuration.

On the basis of the above construction, the inertial force detection valve 27 provided in the connecting rod 1 has the piston 4
The oil passage 18 is opened / closed by detecting the inertial force in the reciprocating direction. In other words, the operating state of the engine is the predetermined number of revolutions (3000
rpm), an inertial force exceeding a predetermined amount acts on the mass body 25, and the mass body 25 opens the oil passage 18 against the biasing force of the coil spring 26. Then, when the operating state of the engine falls below a predetermined rotation speed (3000 rpm), the biasing force of the coil spring 26 overcomes the inertial force acting on the mass body 25 to close the oil passage 18.

However, according to the present embodiment, the lubricating oil from the injection hole 22 is prevented from reaching the maximum output (torque) point of the engine, that is, from the time when the predetermined rotation speed (3000 rpm) is reached, only on the high rotation side. Since the injection is performed, the lubricating oil discharged from the oil pump is not consumed at the time of low rotation where it is not necessary to cool the piston 4 intentionally.

As a result, the consumption amount of the lubricating oil is reduced at the time of low rotation where the discharge capacity of the oil pump is low, so that even an oil pump with a small discharge capacity can sufficiently lubricate the entire engine. The power loss for operating the oil pump can be reduced accordingly.

Moreover, since the piston 4 is not cooled at the time of low rotation such as idling immediately after the engine is started, it is possible to obtain the advantage that the warm-up is promoted.

Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, an inertial force detection valve 53 composed of a mass body 51 and a coil spring 52 (elastic body).
Is disposed at the small end side end portion 55 of the oil passage 54.

That is, the end 55 on the small end side of the oil passage 54
A valve chamber 56 having a diameter larger than that of the oil passage 54 is formed therein, and the coil spring 52 is housed in the valve chamber 56 on the small end side and the mass body 51 is housed in the large end side. A valve seat 58 having a hollow portion 57 having a diameter smaller than that of the body 51 is press-fitted and fixed to contract the coil spring 52, and the oil passage 54 is kept closed.

The oil passage 54 is opened when the operating condition of the engine exceeds a predetermined rotation speed, that is, when an inertial force exceeding a predetermined amount acts on the mass body 54 when the rotation speed exceeds the predetermined rotation speed. To open the oil passage 54 in the mass body 51
And the spring constant of the coil spring 52 are set.

However, the predetermined number of revolutions is set to the number of revolutions at which cooling of the piston should be started, and in the present embodiment, the oil passage 54 is opened when the engine reaches 3000 rpm, which is lower than the maximum output (torque) point of the engine. Inertial force detection valve 5
3 settings have been made. The other configurations are the same as those in the first embodiment, and the same numbers are assigned and the description thereof is omitted.

Based on such a configuration, the inertial force acting on the mass body 51 itself is mainly composed of the component in the reciprocating motion of the piston 4, so that the oil passage 54 can be opened and closed more reliably. Therefore, there is no variation in the supply of the lubricating oil toward the rear surface of the piston, and stable cooling of the piston can be obtained.

In each of the above embodiments, the inertial force detection valve is arranged so as to open the oil passage when the piston is descending, but the invention is not limited to this, and the inertial force detecting valve is arranged so that the oil passage is opened while the piston is rising. It is also possible to provide a force detection valve. In this case, the mass body is housed on the small end side and the coil spring is housed on the large end side in the valve chamber.

In each of the above embodiments, the piston and the connecting rod are connected to each other via the piston pin. However, the invention is not limited to this. For example, the connecting rod and the piston pin are integrated into the piston. It is also applicable to the type connected to.

[0040]

As described above, according to the present invention, the lubricating oil can be supplied toward the rear surface of the piston only at the time of high rotation where cooling of the piston is required, and the discharge capacity of the oil pump can be reduced. Since the consumption of lubricating oil at low and low speeds is reduced, even an oil pump with a small discharge capacity can fully cover the lubrication of the entire engine, and that much power loss for operating the oil pump. Can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram according to a first embodiment of the present invention.

FIG. 2 is an enlarged view showing an inertial force detection valve.

FIG. 3 is a diagram for explaining the action of the inertial force detection valve.

FIG. 4 is a diagram according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a conventional lubricating oil passage structure of a connecting rod.

[Explanation of symbols]

 1 ... Connecting rod 2 ... Small end part 3 ... Large end part 4 ... Piston 5 ... Crank shaft 18 ... Oil passage 22 ... Injection hole 25 ... Mass body 26 ... Coil spring (elastic body) 27 ... Inertial force detection valve

Claims (1)

[Claims] 1. A small end portion connected to a piston is provided at one end,
A connecting rod having a large end connected to the crankshaft at the other end; an oil passage formed in the connecting rod for guiding the lubricating oil supplied from the crankshaft from the large end to the small end; A lubricating oil passage structure for a connecting rod, comprising: a communication hole that is directed toward the rear surface of the piston and is open to a small end. A mass body that opens and closes the oil passage and the oil passage is closed in the oil passage. An inertial force detection valve that opens the oil passage against an urging force of the elastic body when an inertial force exceeding a predetermined amount acts on the mass body. A lubricating oil passage structure for a connecting rod, characterized in that.