JP2005076627A - Piston cooling device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston cooling device for an internal combustion engine capable of always obtaining stable sealing performance without requiring an accurate seal surface. <P>SOLUTION: In order to spray the oil inside a main oil passage formed in a cylinder block to a back surface of the piston through an oil jet formed of a seal surface formed in a pipe having the oil passage, or a seat surface of a valve element for opening/closing the seat surface, or an elastic member for energizing the seal surface in a direction for closing the oil passage, any one of the pipe or the valve element is formed with a tapered (projecting) seal surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piston cooling device for an internal combustion engine, and more particularly to an oil jet that cools a piston by spraying oil onto the back surface of the piston.

  Conventionally, it is shown in Patent Document 1 described below. As shown in FIG. 7 (FIG. 1 of Patent Document 1), the plunger 13 is accommodated in the cylinder 3a of the plunger casing 3 with a clearance maintained in the circumferential direction, and the protruding portion 14 extending from the end surface is provided as a plunger. The support hole 10 is fitted. A flange 15 as a spring locking portion protrudes from the peripheral surface of the plunger 13 and is brought into sliding contact with the inner peripheral surface of the plunger casing 3, and the flange 15 is shown in FIG. 8 (FIG. 2 of Patent Document 1). In this way, the fan-shaped oil passage 16 is divided into four equal parts. Further, a valve-opening pressure setting spring 17 is disposed between the flange 15 and the annular member 9, and the end surface of the plunger 13 is pressed against the bottom wall 7 to close the input port 6. Further, a valve opening pressure correcting spring 18 is disposed between the plunger 13 and the bottom wall 7 to urge the plunger 13 toward the plunger support hole 10 side. The difference between the diameter D1 of the input port 6 and the diameter D3 of the plunger 13 is made as small as possible without affecting the sealing performance, and the end of the plunger 13 is directly fitted into the plunger support hole 10 of the annular member 9. is there.

JP-A-9-324627 (page 3-4, FIGS. 1 and 2)

  Conventionally, the difference between the diameter D1 of the input port 6 and the diameter D3 of the plunger 13 is set small within a range that does not affect the sealing performance, so the inner diameter of the input port 6, the outer diameter of the plunger 13, and the plunger casing 3 The inner diameter of the steel must be processed with high accuracy, and processing accuracy was required. Therefore, the annular seal area formed by the input port 6 and the plunger 13 is not equal left and right, and there is a risk of oil leaking. In order to solve this problem, an object of the present invention is to provide a piston cooling device for an internal combustion engine that does not require a highly accurate sealing surface and can always obtain a stable sealing surface.

  According to a first aspect of the present invention, there is provided a valve body including a valve seat having a seal surface having an oil passage, and a seat surface for opening and closing the valve seat. And a piston cooling device for an internal combustion engine that sprays oil onto the back surface of the piston via an oil jet comprising an elastic member that biases the valve body in the closing direction. The valve body is provided with a flat seat surface so that the oil passage is opened and closed by separating the seal surface from the seat surface. The elastic member described in the claims corresponds to the spring described in the specification.

  Since the valve seat is provided with a convex sealing surface and the valve body is provided with a flat seat surface, the hysteresis at the time of opening and closing due to a narrow sealing area is small and the sealing performance is stabilized.

  According to a second aspect of the present invention, there is provided a valve body including a valve seat having a seat surface having an oil passage, and a seal surface for opening and closing the valve seat. And a piston cooling device for an internal combustion engine that sprays oil onto the back surface of the piston via an oil jet comprising an elastic member that urges the oil passage in a closing direction of the oil passage, and is flat on the valve seat A seat surface is provided, and the valve body is provided with a convex seal surface so that the oil passage is opened and closed by separating the seal surface from the seat surface.

  By providing a flat seat surface on the valve seat and a convex sealing surface on the valve body, the hysteresis at the time of opening and closing due to a narrow seal area is small and the sealing performance is stable.

  According to a third aspect of the present invention, there is provided a valve body including a valve seat having a seal surface having an oil passage and a seat surface for opening and closing the valve seat. And a piston cooling device for an internal combustion engine that sprays oil onto the back surface of the piston via an oil jet comprising an elastic member that urges the oil passage in a closing direction of the oil passage, wherein the valve seat has a tapered shape The valve body is provided with a flat seat surface so that the oil passage is opened and closed by separating the seal surface from the seat surface.

  Since the valve seat is provided with a tapered sealing surface and the valve body is provided with a flat seat surface, hysteresis at the time of opening and closing due to a narrow sealing area is small and the sealing performance is stabilized.

  According to a fourth aspect of the present invention, there is provided a valve body including a valve seat having a seat surface having an oil passage, and a seal surface for opening and closing the valve seat. And a piston cooling device for an internal combustion engine that sprays oil onto the back surface of the piston via an oil jet comprising an elastic member that biases the valve body in a closing direction of the oil passage, and is flat on the valve seat A seat surface is provided, and the valve body is provided with a taper-shaped seal surface, whereby the oil passage is opened and closed by separating the seal surface from the seat surface.

  Since the valve seat is provided with a flat seat surface and the valve body is provided with a tapered sealing surface, the hysteresis at the time of opening and closing due to a narrow sealing area is small and the sealing performance is stabilized.

  According to the configuration of the present invention, the sealing surface of either the valve seat or the valve body is convex (tapered) and has a narrow sealing surface shape, and the other is a flat seat surface. Even if it is slightly deviated in the direction, the seal area does not change, a predetermined pressure regulation is always obtained, and sludge is not accumulated on the seal surface.

  Example 1 of the present invention will be described in detail with reference to the drawings. 1 is a sectional view showing the whole piston cooling device, FIG. 2 is a sectional view showing the whole oil jet, FIG. 3 is a view showing a state when the oil jet is closed, and FIG. 4 is a partially enlarged view of a seat portion. It is. In FIG. 1, an internal combustion engine (hereinafter referred to as an engine) 1 includes a cylinder block 2 and a plurality of cylinders 3 arranged in parallel. A piston 4 is inserted into the cylinder 3 so that it can slide up and down. One end of the connecting rod 5 is connected to a crankshaft (not shown), and the other end is connected to a piston pin 6 fixed to the piston 4. As the crankshaft rotates, the connecting rod 5 moves up and down and the piston 4 moves up and down in the cylinder 3. The upper surface of the piston 4 is combined with the cylinder head to form a combustion chamber. A skirt 7 communicating with the crankcase is formed at the lower part of the piston 4.

  A main oil passage 8 is formed at the lower end of the cylinder block 2 and is arranged in parallel with the plurality of cylinders 3. One end of the oil passage 9 is connected to a position corresponding to the cylinder 3 in the main oil passage 8, and the other end is open to the lower end surface 2 a of the cylinder block 2. A screw is engraved in the opening 10 and an oil jet 11 is attached.

  The oil jet 11 is configured as follows. As shown in FIGS. 2 and 3, the union bolt 12 is screwed into the cylinder block 2 via a union nipple 13. The union bolt 12 has a hole 14 with a bottom. A valve seat 15 is press-fitted into the hole 14 to a predetermined position. A seal surface 15 a is formed on the lower end surface of the valve seat 15. As shown in an enlarged view in FIG. 3, the cross-sectional shape of the seal surface 15 a is a tapered shape and is substantially V-shaped (convex). The seal diameter d1 of the seal surface 15a is slightly larger than the inner diameter d2 of the oil passage 17 formed in the valve seat 15 as shown in FIG. Specifically, the seal surface 15a is formed of an arc having a seal diameter d1 of about 1 to 10 mm and a radius R of about 0.1 to 1 mm.

  The bottomed valve body 18 is inserted into the hole 14 so as to be opposed to the seal surface 15a. The valve body 18 has a bottomed cup shape, and has a sheet surface 18b formed on the bottomed side and has a flat shape. A spring 20 is inserted between the bottom surface 14a of the hole 14 and the bottom surface 19 of the valve body 18 to urge the valve body 18 toward the seal surface 15a with a predetermined spring force. The union bolt 12 is provided with an oil discharge port 21 that communicates across the hole 14. A hole 22 is formed in the union nipple 13 and communicates with the oil discharge port 21. One end of a nozzle 24 is press-fitted into the hole 22 and fixed. The nozzle 24 is tubular and is formed in an approximately L shape. An orifice 25 is formed at the other end of the nozzle 24. The injection direction of the nozzle 24 faces the back direction of the piston 4. The atmospheric hole 26 is opened in communication with the hole 14 of the union bolt 12.

  Next, the operation will be described. At start-up, the engine 1 is cold, the oil viscosity is high, and the engine speed is not so high. Therefore, the discharge pressure of the oil pump that supplies the oil is low, and the valve does not open overcoming the urging force of the spring 20. Therefore, since oil is not supplied to the back surface of the piston 4, the piston 4 is not supercooled by the oil. When the engine 1 is warmed up and the engine speed is increased, the oil pressure of the oil pump is increased, the urging force of the spring 20 is overcome, the seat surface 18b of the valve body 18 is separated from the seal surface 15a, and the oil passes through the oil discharge port 21. Then, it is injected from the orifice 25 of the nozzle 24 toward the back surface of the piston 4. As a result, the piston 4 is appropriately cooled, and the lubricating oil is continuously supplied to the piston pin 6 to prevent the bearing from being seized.

  According to this embodiment, the sealing surface of the valve seat is tapered and has a substantially V-shaped (convex) sealing surface shape, and the valve body is a flat seat surface. The seal area does not change, a predetermined pressure regulation is always obtained, and the effect is that sludge is not accumulated because the seal surface is tapered.

  Next, it differs from Example 1 which demonstrates Example 2 of a valve body in the point by which the seal surface and the seat surface are reversed. As shown in FIG. 5, the cross-sectional shape of the sealing surface is a tapered shape and is substantially V-shaped (convex). A tapered sealing surface 18 a is provided on the back surface of the valve body 18. The seal diameter d1 of the seal surface 18a is slightly larger than the inner diameter d2 of the oil passage 17 of the valve seat 15 as shown in FIG. Specifically, the seal surface 18a is formed in an arc shape with a seal diameter d1 of about 1 to 10 mm and a radius R of about 0.1 to 1 mm.

  According to this embodiment, the sealing surface of the valve body is a tapered (convex) sealing surface, and the valve seat is a flat seat surface. A predetermined pressure regulation is always obtained. Moreover, since the sealing surface is formed in a tapered shape, an effect that sludge is not accumulated can be obtained.

It is sectional drawing which shows the whole piston cooling device which concerns on Example 1. FIG. 1 is a cross-sectional view illustrating an entire oil jet according to a first embodiment. It is a figure which shows the state at the time of valve closing of the oil jet which concerns on Example 1. FIG. 3 is an enlarged view of a seat portion of the oil jet according to Embodiment 1. FIG. It is a figure which shows the state at the time of valve closing of the oil jet which concerns on Example 2. FIG. 6 is an enlarged view of a seat portion of an oil jet according to Embodiment 2. FIG. It is sectional drawing which shows the whole conventional oil jet. It is sectional drawing which shows the principal part of the conventional oil jet.

Explanation of symbols

2: Cylinder block 4: Piston 8: Main oil passage 9: Oil passage 11: Oil jet 15: Valve seat 15a, 18a: Seal surface 15b, 18b: Seat surface 18: Valve body 20: Spring (elastic member)

Claims (4)

A valve seat having a seal surface having an oil passage, a valve body having a seat surface for opening and closing the valve seat, and oil in the main oil passage formed in the cylinder block; A piston cooling device for an internal combustion engine that blows oil to the back surface of the piston via an oil jet composed of an elastic member that biases in the closing direction,
The valve seat has a convex sealing surface, and the valve body has a flat seat surface, whereby the oil passage is opened and closed by separating the seal surface from the seat surface. Engine piston cooling device. A valve seat having a seat surface having an oil passage, oil in a main oil passage formed in the cylinder block, a valve body having a seal surface for opening and closing the valve seat, and the valve body in the oil passage A piston cooling device for an internal combustion engine that blows oil to the back surface of the piston via an oil jet composed of an elastic member that biases in the closing direction,
The valve seat has a flat seat surface, and the valve body has a convex sealing surface, whereby the oil passage is opened and closed by separating the sealing surface from the seat surface. Engine piston cooling device. A valve seat having a seal surface having an oil passage, oil in a main oil passage formed in the cylinder block, a valve body having a seat surface for opening and closing the valve seat, and the valve body in the oil passage A piston cooling device for an internal combustion engine that blows oil to the back surface of the piston via an oil jet composed of an elastic member that biases in a closing direction,
The valve seat has a tapered sealing surface, and the valve body has a flat seat surface, whereby the oil passage is opened and closed by separating the sealing surface from the seat surface. Engine piston cooling device. A valve seat having a seat surface having an oil passage, oil in a main oil passage formed in the cylinder block, a valve body having a seal surface for opening and closing the valve seat, and the valve body in the oil passage A piston cooling device for an internal combustion engine that blows oil to the back surface of the piston via an oil jet composed of an elastic member that biases in the closing direction,
The valve seat has a flat seat surface, and the valve body has a tapered sealing surface to open and close the oil passage by separating the seal surface from the seat surface. Engine piston cooling device.

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