JPH0533688Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an engine chain lubricating device, and particularly to an improvement in an oil pump provided in a chain cover that covers the chain.

(Prior Art) Conventionally, in an engine, a chain cover for storing a conduction band such as a balancer chain or belt is removably attached to the outer surface of the engine body, and the chain cover, which houses the conduction band such as a chain or belt for a balancer, is attached to the cover in a detachable manner. It is known that a pump is integrally provided.

In order to lubricate the chain housed in the chain cover and the sprocket around which the chain is wound, an oil jet is provided protruding inside the chain cover and communicates with an oil supply passage formed on the engine body side. Alternatively, by disposing a pipe constituting an oil supply passage inside the chain cover and connecting an oil jet to the pipe, oil is sprayed from the oil jet onto the chain (Japanese Patent Laid-Open No. 57-5509). (Refer to official bulletins, etc.)

However, in the conventional type described above, in order to sufficiently lubricate the chain and sprocket, it is necessary to provide multiple oil jets corresponding to various parts of the chain, and this results in structural problems due to the relationship with the oil supply passage. The problem was that it was complicated.

In order to solve this problem, for example, as disclosed in Japanese Patent Publication No. 57-131808, the oil pump cover on the chain chamber side of the oil pump installed in the chain cover is provided with an oil pump cover facing the chain. It has been proposed that an oil passage is provided which opens at the end of the chain, and oil is discharged from the oil passage to the chain for lubrication.

(Problem to be solved by the invention) However, since the oil passage is always open to the outside (toward the chain installation side), even when the pressure inside the oil pump is low (at low speed), There is a problem in that the oil required for lubrication is discharged into the chain via the oil passage, which deteriorates the efficiency of the oil pump at low pressures and makes it impossible to stabilize the oil pressure.

On the other hand, in an oil pump, when the pressure on the discharge side (high pressure part) of the oil pump exceeds the set pressure, the relief valve opens and directs the discharged oil to the oil pan or suction side of the oil pump. configured to return.

The present invention has been developed in view of these points, and its purpose is to focus on the relief valve that opens when the pressure in the high pressure section of the oil pump exceeds the set pressure, as described above. The purpose of the present invention is to effectively utilize a relief valve to stabilize the pressure in a high-pressure part of an oil pump, and to perform chain lubrication with a simple structure and in good condition.

(Means for Solving the Problems) In order to achieve the above object, the solution of the present invention is that a chain cover that covers the chain is removably attached to the outer surface of the engine body, and a crankshaft is attached to the chain cover. An engine equipped with an oil pump that is driven and whose pressure increases as the engine speed increases has the following configuration.

That is, in the oil pump, the pump chamber is formed by attaching the oil pump cover to the chain cover from the chain chamber side, and the high pressure portion of the pump chamber extends to the sliding contact portion between the chain and the chain guide. The pump chamber is provided with a relief passage that opens in communication with the high-pressure section by opening a relief valve when the pressure of the high-pressure section exceeds a set pressure. An oil passage is provided at a position facing the contact part, which opens in communication with the high pressure part when the pressure in the high pressure part reaches a predetermined pressure higher than the set pressure, when the relief valve is opened. . Furthermore, the cross-sectional area of the oil passage is formed to be smaller than the passage cross-sectional area of the relief passage, and the oil passage is configured to be formed into a jetting hole that jets oil to the sliding contact portion. be.

(Function) With the above configuration, in the present invention, when the pressure in the high pressure part of the pump chamber has not reached the set pressure, the relief valve does not open and the relief passage is kept closed, so that the high pressure When the pressure in the high-pressure section of the pump chamber is low, less than a predetermined pressure, the oil in the high-pressure section of the pump chamber is not discharged through the oil passage, and the efficiency of the oil pump at low pressure is increased. On the other hand, when the discharge pressure becomes equal to or higher than the set pressure, the relief valve is opened to open the relief passage, and the oil in the high pressure section of the pump chamber is discharged to ensure sufficient relief performance.

Additionally, when the pressure in the high pressure section reaches a predetermined pressure higher than the set pressure, the oil passage facing the sliding contact between the chain and the chain guide opens to the high pressure section by opening the relief valve. , the oil in the high pressure section is vigorously discharged towards the sliding contact section,
This oil sufficiently lubricates the chain and chain guide.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 and 2 show a chain lubricating system for an engine according to an embodiment of the present invention, in which 1 is a cylinder block, 2 is an oil pan attached to the lower part of cylinder block 1, and 3 is cylinder block 1. a crankshaft disposed within the cylinder block 1 of the crankshaft 3;
A large-diameter first drive sprocket 4 and two connected small-diameter second drive sprockets 5 are mounted on the forward extending portion 3a from positions axially distant from the cylinder block 1 in a front-back relationship. There is. Further, 6 and 7 are gears and driven sprockets mounted on left and right balancer shafts (not shown), and an idler sprocket 8 that meshes with the gear 6 is provided near the gear 6. Of the above sprockets, the first driving sprocket 4, the driven sprocket 7, and the idler sprocket 8 are equipped with a balancer chain 9.
However, on the other hand, a timing chain 10 is wound around the second drive sprocket 5 and a driven sprocket on the camshaft side (not shown), respectively. The balancer chain 9 is
Chain guides 11a, 11b, and 11c guide the parts between the idler sprocket 7 and the idler sprocket 8, between the idler sprocket 8 and the first drive sprocket 4, and between the first drive sprocket 4 and the driven sprocket 7, respectively. It is becoming more and more common.

Further, a chain cover 12 is arranged on the front outer surface of the cylinder block 1 to cover each of the chains 9 and 10. The chain cover 12
is located at the end of the extending portion 3a of the crankshaft 3 to which each drive sprocket 4, 5 is attached, is formed in a bag shape that opens rearward (toward the cylinder block 1), and is detachably attached to the cylinder block 1. And it is attached and installed in an oil seal state,
Each chain 9, 10 between cylinder block 1
It is designed to store.

The chain cover 12 has an oil pump housing 1 corresponding to the crankshaft 3.
3 is formed, and an oil pump 14 driven by the crankshaft 3 is accommodated within the housing 13. The oil pump 14 is of an internal gear type having an externally toothed driving gear 15 and an internally toothed driven gear 16 as a pump rotor, and the externally toothed driving gear 15 is fitted and fixed to the crankshaft 3. The internal driven gear 16 is connected to the housing 13
is rotatably fitted within.

As shown in FIG. 3, the chain cover 12 has two parts on the rear side (facing the cylinder block 1).
A plurality of bolt bosses 1 having screw holes or bolt insertion holes for connection to the cylinder block 1
7,... are formed at the lower end of the chain cover 12, as shown in FIG.
The upper end of the front edge of is attached by bolts 18. Note that 19 is a crankshaft penetrating portion around which the oil pump housing 13 is formed.

The oil pump housing 13 has an oil pump chamber 22 in which the oil pump 14 is housed formed by attaching the peripheral edge of an oil pump cover 20 shown in FIG. 4 with bolts 21 to the outer peripheral wall 13a thereof. There is. The oil pump chamber 22
A low pressure chamber 23 (the left half of the pump chamber 22 in FIG. 3) and a high pressure chamber 24 (the right half of the pump chamber 22 in the figure) are formed. Above oil pump chamber 2
2 is a low pressure chamber 23 and a high pressure chamber 24, as well as an upper driven sprocket 7 and an idler sprocket 8.
It is formed in a vertically elongated shape and extends to a sliding contact portion A between the balancer chain 9 and the chain guide 11a located between the balancer chain 9 and the chain guide 11a. Further, an inlet 25 is provided at the lower end of the housing 13 at the lower end of the circumferential direction on the low pressure chamber 23 side.
is open, and the suction port 25 is communicated with an introduction pipe 26 (see FIGS. 1 and 2) via a suction passage (not shown) formed in the chain cover 12, and the suction port 25 of the oil pan 2 is opened. The oil accumulated at the bottom flows into the low pressure chamber 23 of the housing 7 through an oil strainer 27.
It is becoming more inhaled. On the other hand, a discharge port 28 is opened at the upper end of the housing 13 in the circumferential direction on the high pressure chamber 24 side, and the oil whose pressure has been increased in the housing 13 by the operation of the oil pump 14 is discharged from the discharge port 28. It is designed to be discharged outside the chain cover 12 (on the side where each chain 9, 10 is disposed) via a passage 29. Further, an oil pump drain passage 30 is formed in the lower part of the chain cover 12, and an oil pump drain passage 30 is formed in the lower part of the chain cover 12.
The leakage oil from the oil pan 4 is returned to the oil pan 2 through the oil pump drain passage 30.

In addition, the oil pump housing 13 rotatably guides the internal driven gear 16 of the oil pump 14 by the outer circumferential wall 13a in the lower half thereof, while the oil pump housing 13 rotatably guides the internal driven gear 16 of the oil pump 14 by the outer circumferential wall 13a in the upper half. The internal driven gear 16 is rotatably guided by guide walls 31 provided at intervals, and a rectangle extending along the guide wall 31 is provided between the guide wall 31 and the outer peripheral wall 13a. A curing passage 32 is formed.
One end of the respiration passage 32 is communicated with the vicinity of the suction port 24 of the low pressure chamber 23, while the other end is communicated with the valve housing 33 formed in the oil pump cover 20 through a communication hole 34. It is communicated. The valve housing 33 has a fifth
As shown in the figure, it communicates with the discharge port 28, and a relief valve 35 is provided inside thereof. The relief valve 35 includes a valve body 36 that is slidably inserted into the valve housing 33, an adjustment screw 37 that is screwed into the opening of the valve housing 33, and a valve body 36 that is arranged between the valve body 36 and the adjustment screw 37. The spring 38 is compressed into a spring 38. in this case,
In the valve housing 33, the discharge port 28 and the communication hole 34 are prevented from communicating by the valve body 36 of the relief valve 35 when the discharge pressure of the high pressure chamber 24 of the oil pump 14 has not reached the set pressure. On the other hand, when the discharge pressure reaches the set pressure, the valve body 3 opens against the urging force of the spring 38.
6, and the respiration passage 32 is configured as a relief passage including the inside of the valve housing 33.

As a feature of the present invention, the oil pump cover 20, which is attached to the oil pump chamber 22 whose upper portion extends to the sliding contact area A between the balancer chain 9 and the chain guide 11a, has a sliding contact area A as described above. When the discharge pressure opposite to the high pressure chamber 24 and discharged to the outside of the chain cover 12 through the discharge passage 29 reaches a predetermined pressure higher than the set pressure, the relief valve 35 is opened. An oil passage 39 is provided which communicates with and opens to the high pressure chamber. The cross-sectional area of the oil passage 39 is smaller than the passage cross-sectional area of the introduction pipe 26 in the middle of the relief passage.
Reference numeral 9 is formed as an ejection hole for ejecting oil to the sliding contact portion A. In this case, the discharged oil flows from the high pressure chamber 28 side to the respiration passage 3.
2 (relief passage) to be returned to the low pressure chamber 23 side.

Next, to describe the operation of the above embodiment, when the discharge pressure of the high pressure chamber 24 of the oil pump chamber 22 has not reached the set pressure, the relief valve 35 does not open and the recirculation passage 32 is opened to high pressure. The communication hole 34 is kept closed so as not to communicate with the chamber 24, so that the oil in the high pressure chamber 24 of the oil pump chamber 22 is not discharged through the oil passage 39, and the oil pump 14 at low pressure is kept closed. Efficiency is increased and hydraulic pressure can be stabilized at low pressures below the set pressure.

On the other hand, when the discharge pressure of the high pressure chamber 24 exceeds the set pressure, the relief valve 35 is operated to open, and the communication hole 34 is opened so that the recirculation passage 32 communicates with the high pressure chamber 24, and the oil passage 39 is opened. The oil in the high pressure chamber 24 of the oil pump chamber 22 is discharged through the oil pump chamber 22 to ensure sufficient relief performance, and the reliability of the hydraulic system including the oil pump 14 can be ensured.

Further, when the discharge pressure of the high pressure chamber 24 reaches a predetermined pressure higher than the set pressure, the oil passage 39 facing the sliding contact portion A with the balancer chain 9 and the chain guide 11a is further opened by the relief valve 35. When activated, the valve housing 33 opens into the high pressure chamber 24, so the oil in the high pressure chamber 24 is vigorously discharged toward the sliding contact area A, and the balancer chain 9 and chain guide 11a are sufficiently moved by this oil. The oil pump 14 is lubricated and when the pressure is higher than a predetermined pressure higher than the set pressure.
In addition to increasing the efficiency of the operation, the sliding contact portion A between the balancer chain 9 and the chain guide 11a can be sufficiently lubricated by the oil discharged from the oil passage 39 even if the oil jet is eliminated.

(Effect of the invention) As described above, according to the engine chain lubricating device of the present invention, the high pressure part of the pump chamber is extended to the sliding contact part between the chain and the chain guide, and the oil pump cover is connected to the sliding contact part. An oil passage is provided opposite to the high-pressure part and opens in communication with the high-pressure part by opening the relief valve when the pressure in the high-pressure part reaches a predetermined pressure higher than the set pressure. When the pressure in the high pressure section is low, below the set pressure, the oil passage is closed, increasing the efficiency of the oil pump and stabilizing the oil pressure.However, when the discharge pressure exceeds the set pressure, the relief valve is closed. When activated, the relief passage is opened, sufficient relief performance can be ensured, and the reliability of the hydraulic system including the oil pump can be ensured. Moreover,
When the pressure in the high pressure section is higher than a predetermined pressure, the oil passage is opened by the opening operation of the relief valve, and in order to increase the efficiency of the oil pump at high pressure, the oil discharged from the oil passage is also used to protect the chain and chain guide. This means that sufficient lubrication of the sliding contact area can be achieved even if the oil jet is abolished.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a sectional view taken in the axial direction around the crankshaft, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a cross-sectional view of the chain. The rear view of the cover, Figure 4 is the rear view of the oil pump cover, Figure 5
The figure is a sectional view taken along the - line in FIG. 4. 3... Crankshaft, 9... Balancer chain, 11a... Chain guide, 12... Chain cover, 14... Oil pump, 20... Oil pump cover, 22... Oil pump chamber, 2
4...High pressure chamber, 35...Relief valve, 39...Oil passage, A...Sliding contact part.

Claims (1)

[Claim for Utility Model Registration] A chain cover that covers the chain is removably attached to the outer surface of the engine body, and the chain cover is equipped with oil that is driven by the crankshaft and whose discharge pressure increases as the engine speed increases. In an engine equipped with a pump, the oil pump has a pump chamber formed by attaching an oil pump cover to the chain cover from the chain chamber side, and the high pressure part of the pump chamber is formed by sliding contact between the chain and the chain guide. The pump chamber is provided with a relief passage that opens in communication with the high pressure section by opening the relief valve when the pressure in the high pressure section exceeds the set pressure. In addition, at a position of the oil pump cover opposite to the sliding contact portion, when the pressure of the high pressure portion reaches a predetermined pressure higher than the set pressure, the relief valve is opened to cause the high pressure portion to open. An oil passage that opens in communication is provided, and a passage cross-sectional area of the oil passage is formed to be smaller than a passage cross-sectional area of the relief passage,
A chain lubricating device for an engine, wherein the oil passage is formed in a jet hole that jets oil to the sliding contact portion.