JP5673029B2 - Oil pump relief structure - Google Patents

Description

  The present invention relates to a relief structure for an oil pump, and in particular, a relief structure for an oil pump that prevents foreign matter from being caught by a relief valve by changing the shape of a relief oil outlet for adjusting the hydraulic pressure of oil discharged from the oil pump. About.

An oil pump that is driven by the crankshaft of the engine and discharges oil forms a pump chamber in which the oil pump case is attached in the chain case to expand and contract, and the oil is sucked into the pump chamber through the suction passage and compressed. There are some which discharge discharged oil into a discharge passage and supply it to various parts of the engine. The oil pump has a relief structure that returns part of the oil in the discharge passage to the suction passage in order to adjust the oil pressure of the discharged oil.
As shown in FIG. 7, in the relief structure of the oil pump 101, a relief oil passage 105 that connects the discharge passage 104 and the suction passage is provided in the oil pump case 103 attached to the chain case 102. A cylindrical valve body 106 is disposed on the side. The valve body 106 has a valve hole 108 formed in the side wall 107.
In the valve body 106, one side of the side wall 107 in the circumferential direction is connected to the bottom surface portion 110 of the relief oil passage 105 by a connecting portion 109. The valve body 106 is formed with a relief oil inlet 111 communicating with the discharge passage 104 at one axial end portion of the valve hole 108, and on the side wall 107 opposed to the circumferential side of the side wall 107 of the valve body 106 with the connecting portion 109 interposed therebetween. Relief oil outlets 112 communicating with the suction passages are formed.
As shown in FIG. 8, the valve body 106 has a relief valve 113 slidably disposed in the valve hole 108. The relief valve 113 is urged toward the relief oil inlet 111 by a spring 114. The relief valve 113 is moved in the axial direction away from the relief oil inlet 111 against the urging force of the spring 114 by the hydraulic pressure of the oil flowing from the discharge passage 104 to the relief oil inlet 111, and the movement in the axial direction is caused by this movement in the axial direction. Open the relief oil outlet 112.
When the relief oil outlet 112 is opened, the oil pump 101 discharges a part of the oil in the discharge passage 104 to the suction passage through the relief oil passage 105 to adjust the oil pressure of the oil.

  In such a relief structure of the oil pump, a plurality of relief oil outlets are opened evenly in the cross section of the valve hole, and the rate of increase in the opening area is proportional in the initial opening of the relief oil outlet due to the opening operation of the relief valve. In some cases, the relief oil outlet is formed in an increasing shape, thereby improving the relief performance by stabilizing the opening of the relief oil outlet by the relief valve. (Patent Document 1)

Japanese Utility Model Publication No.7-1375

By the way, in the relief structure of the conventional oil pump 101, as shown in FIG. 8, the oil that has flowed into the valve hole 108 from the relief oil inlet 111 flows to the relief oil outlet 112. At this time, in the valve hole 108, as indicated by an arrow, the oil flows toward the relief oil outlet 112 toward the bottom face 110 (the connecting part 109 in the valve hole 108) of the relief oil passage 105. Itching W occurs.
When foreign matter mixed in the oil pump 101 enters the relief oil passage 105, the foreign matter tends to stay in the stagnation W of the relief oil in the valve hole 108, and the foreign matter is placed between the relief valve 113 and the relief oil outlet 112. There is a problem of pinching.

  An object of the present invention is to prevent foreign matter from being caught between a relief valve and a relief oil outlet of a relief valve of an oil pump.

According to the present invention, a cylindrical valve body in which a valve hole in which a relief valve slides is formed is disposed in a relief oil passage, and a bottom surface of the relief oil passage is provided on one circumferential side of the valve body by a connecting portion. A relief oil inlet is formed at one end of the valve hole in the axial direction, and a relief oil outlet is formed on each side wall facing the coupling part in the circumferential direction of the valve body. A relief valve that moves in the axial direction by the hydraulic pressure of the oil flowing into the relief oil inlet and opens the relief oil outlet is disposed, and the oil that flows out from the relief oil outlet is directed to the opposite side of the bottom surface of the relief oil passage. in the relief structure of the oil pump that constitutes the relief oil passage to flow, the valve When viewed from a direction perpendicular to Di to the axis of the valve hole the axis to the plane including the straight line obtained by projecting on the bottom surface of the relief oil passage, the relief oil outlet, the bottom surface portion of the relief oil passage A first side that is close to the outer edge of the valve body located on the opposite side of the valve body and extends in parallel with the axis of the valve hole, and extends beyond the axis of the valve hole from the end of the first side on the relief oil inlet side A second side that extends toward the bottom surface side of the relief oil passage and is inclined to move away from the relief oil inlet as it approaches the bottom surface portion of the relief oil passage, and a third side that connects the end portions of these two sides It was formed in the substantially triangular shape provided with.

According to the relief structure of the oil pump of the present invention, when the opening area of the relief oil outlet is small, the opening position of the relief oil outlet can be opened to a position where the flow of relief oil away from the bottom surface of the relief oil oil passage is fast. it can.
As a result, it is possible to prevent foreign matter staying in a place where the oil flow is stagnant from flowing into the opening of the relief oil outlet.
Moreover, it can prevent that the shape of an opening part becomes a long and slender slit shape in the stage where the relief oil exit begins to open, and can prevent that a foreign material is pinched | interposed into an opening part.
Therefore, the relief structure of the oil pump according to the present invention can prevent foreign matter from being caught between the relief valve and the relief oil outlet.

FIG. 1 is a side view of the inside of the oil pump case. (Example) FIG. 2 is a bottom view of the oil pump case. (Example) 3 is a cross-sectional view taken along line AA in FIG. (Example) 4 is a cross-sectional view taken along line BB in FIG. (Example) FIG. 5 is a sectional view of the valve body taken along line AA in FIG. (Example) FIG. 6 is an enlarged cross-sectional view of a portion indicated by an arrow C in FIG. (Example) FIG. 7 is a sectional view of the valve body of the oil pump case. (Conventional example) FIG. 8 is a sectional view of the valve body when the relief valve is opened. (Conventional example)

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

1 to 6 show an embodiment of the present invention. 1 and 2, reference numeral 1 denotes an engine crankshaft, 2 denotes a chain case, and 3 denotes an oil pump. The oil pump 3 has an oil pump case 4 attached in the chain case 2. The oil pump case 4 forms a through hole 5 through which the crankshaft 1 passes. The joint surface 6 of the oil pump case 4 with the chain case 2 is formed with a suction chamber 7 and a discharge chamber 8 on both sides of the through hole 5. The suction chamber 7 communicates with the downstream side of the suction passage 9. The suction passage 9 communicates the suction port 10 at the upstream end with the oil pan. The discharge chamber 8 communicates with the upstream side of the discharge passage 11. The discharge passage 11 communicates the discharge port 12 at the downstream end with the oil gallery of the engine.
The oil pump 3 forms a pump chamber that expands and contracts by an inner rotor that is rotated by the crankshaft 1 and an outer funnel that is eccentrically inscribed in the inner rotor, and the oil in the oil pan is transferred from the suction passage 9 to the pump chamber via the suction chamber 7. Inhalation and compression are performed, and the compressed oil is discharged into the discharge chamber 8. The oil compressed in the discharge chamber 8 is supplied to various parts of the engine of the engine through the discharge passage 11.

The oil pump 3 has a relief structure in which a part of the oil flowing through the discharge passage 11 is returned to the suction passage 9 in order to adjust the hydraulic pressure of the discharged oil. In the relief structure of the oil pump 3, a relief oil passage 13 that connects the discharge passage 11 and the suction passage 9 to the oil pump case 4 is provided. The relief oil passage 13 communicates the start end side with a communication port 14 in the middle of the discharge passage 11 and communicates the terminal end side with a communication port 15 of the suction chamber 7. As shown in FIGS. 3 to 5, a cylindrical valve body 16 is disposed in the relief oil passage 13. The valve body 16 has a valve hole 18 formed in a cylindrical side wall 17 and is disposed in the relief oil passage 13 so that its axis X is directed in the vertical direction.
As shown in FIG. 4, the valve body 16 is connected to the bottom surface portion 20 of the relief oil passage 13 by a connecting portion 19 on one side in the circumferential direction of the side wall 17. The valve body 16 has a relief oil inlet 21 formed at one end of the valve hole 18 in the axial direction, and a relief oil outlet 22 formed on each of the side walls 17 opposed to each other with the connecting portion 19 interposed in the circumferential direction of the valve body 16. Yes. The relief oil inlet 21 communicates with the relief oil passage 13 on the discharge passage 11 side. The relief oil outlet 22 communicates with the relief oil passage 13 on the suction chamber 7 side.
The valve body 16 has a relief valve 23 slidably disposed in the valve hole 18. In the valve hole 18, a plug 24 is attached to an opening end opposite to the relief oil inlet 21, and a spring 25 is mounted between the plug 24 and the relief valve 23. Further, the inside of the valve hole 18 between the plug 24 and the relief valve 23 communicates with the relief oil passage 13 on the suction chamber 7 side by the pressure release hole 26. The relief valve 23 is moved in the axial direction away from the relief oil inlet 21 against the urging force of the spring 25 by the oil pressure of the oil flowing into the relief oil inlet 21 from the discharge passage 11, and the movement in the axial direction is caused by this movement in the axial direction. Open the relief oil outlet 22.
When the relief oil outlet 22 is opened, the oil pump 3 discharges a part of the oil in the discharge passage 11 as relief oil to the suction passage 9 through the suction chamber 7 through the relief oil passage 13 to adjust the oil pressure.

As shown in FIG. 4, the relief structure of the oil pump 3 has a valve body 16 in a plane V including an axis X of the valve hole 18 and a straight line Y that projects the axis X on the bottom surface 20 of the relief oil passage 13. When viewed from a direction orthogonal to the arrow (arrow P), the relief oil outlet 22 is formed in a substantially triangular shape having a first side 27, a second side 28, and a third side 29 as shown in FIG. doing.
The first side 27 is disposed at a position farthest from the bottom surface portion 19 in the depth direction of the relief oil passage 13 and extends parallel to the axis X of the valve hole 18. The second side 28 extends from the end of the first side 27 on the relief oil inlet 21 side toward the bottom surface 20 of the relief oil passage 13, and from the relief oil inlet 21 as it approaches the bottom surface 20 of the relief oil passage 13. It is tilted away. The third side 29 connects the end portion of the first side 27 farthest from the relief oil inlet 21 and the end portion of the second side 28 approaching the bottom surface portion 20 of the relief oil passage 13 again.

Thus, in the relief structure of the oil pump 3, the shape of the relief oil outlet 22 is formed in a substantially triangular shape in which the opening position is farther from the bottom surface portion 20 of the relief oil passage 13 as it is closer to the relief oil inlet 21. When the opening area of the relief oil inlet 21 is small, the opening position of the relief oil outlet 22 can be opened to a position where the flow of relief oil away from the bottom surface portion 20 of the relief oil passage 13 is fast.
As a result, it is possible to prevent foreign matter staying in the place W where the flow of relief oil in the valve hole 18 is stagnant from flowing into the opening portion of the relief oil outlet 22. Further, it is possible to prevent the shape of the opening portion from becoming a long and narrow slit when the relief oil outlet 22 starts to open, and even if foreign matter flows into the opening portion, foreign matter can be prevented from being caught in the opening portion.
Therefore, the relief structure of the oil pump 3 can prevent foreign matter from being caught between the relief valve 23 and the relief oil outlet 22.

Further, as shown in FIG. 6, the relief oil outlet 22 has an opening area S <b> 1 opposite to the bottom surface portion 20 of the relief oil passage 13 with respect to the axis X of the valve hole 17 with respect to the axis X of the valve hole 18. The relief oil passage 13 is formed in a substantially triangular shape larger than the opening area S2 on the same side as the bottom surface portion 20 (S1> S2).
Thereby, the relief structure of the oil pump 3 can open the relief oil outlet 22 to a place where the flow rate of the relief oil is higher.

  The present invention can prevent foreign matter from being caught between the relief valve of the oil pump and the relief oil outlet, and is applicable not only to the relief structure of the oil pump but also to the relief structure of a hydraulic system. Can do.

DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Chain case 3 Oil pump 4 Oil pump case 7 Suction chamber 8 Discharge chamber 9 Suction passage 11 Discharge passage 13 Relief oil passage 16 Valve body 17 Side wall 18 Valve hole 19 Connection part 20 Bottom face part 21 Relief oil inlet 22 Relief oil Outlet 23 Relief valve 25 Spring 27 First side 28 Second side 29 Third side

Claims (2)

A cylindrical valve body with a valve hole inside which the relief valve slides is placed in the relief oil passage.
One side of the valve body in the circumferential direction is connected to the bottom surface of the relief oil passage by a connecting portion,
Forming a relief oil inlet at one end in the axial direction of the valve hole and forming a relief oil outlet on each side wall facing the connecting portion in the circumferential direction of the valve body;
The relief valve that moves in the axial direction by the hydraulic pressure of oil flowing into the relief oil inlet into the valve hole and opens the relief oil outlet is disposed, and the oil that flows out from the relief oil outlet is disposed on the bottom surface of the relief oil passage In the relief structure of the oil pump in which the relief oil passage is configured to flow to the opposite side of the part ,
When the valve body is viewed from a direction perpendicular to a plane including the axis of the valve hole and a straight line obtained by projecting the axis onto the bottom surface of the relief oil passage, the relief oil outlet is connected to the relief oil passage . A first side that is close to the outer edge of the valve body located on the opposite side of the bottom surface and extends parallel to the axis of the valve hole, and an axis of the valve hole from the end of the first side on the relief oil inlet side And a second side that extends to the bottom surface side of the relief oil passage and that is inclined away from the relief oil inlet as it approaches the bottom surface portion of the relief oil passage, and a third side that connects the end portions of these two sides A relief structure for an oil pump, characterized by being formed in a substantially triangular shape with sides.   The relief oil outlet has an opening area opposite to the bottom surface of the relief oil passage with respect to the axis of the valve hole, and an opening area on the same side as the bottom surface of the relief oil passage with respect to the axis of the valve hole. The oil pump relief structure according to claim 1, wherein the relief structure is large.

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