JPH0442552Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to an improvement of an engine oil pump equipped with a regulator valve for regulating discharge pressure.

(Prior Art) Conventionally, as shown in Japanese Utility Model Publication No. 48-34002, gear pump type oil pumps equipped with a regulator valve (safety valve) for adjusting the discharge pressure have been known. The regulator valve has a valve body that slides depending on the discharge pressure,
A relief port is opened and closed by the valve body, and when the discharge pressure of the oil pump exceeds a predetermined value, the relief port is opened to release excess oil from the discharge side.

By the way, as structures for relieving oil using the above-mentioned valve body, there are two types: one in which oil is relieved outside the oil pump (see Figure 2 of the above publication), and one in which oil is returned to the oil suction passage of the oil pump. (See Figure 1 of the above publication). Among these, those in which oil is relieved to the outside of the oil pump cannot compensate for the tendency that as the rotational speed of the pump gear increases, the suction negative pressure increases and the pump efficiency decreases. In contrast, with a structure that returns oil to the oil suction passage, the oil return passage etc. By carefully arranging the pump, the pressure of the oil returned from the discharge side to the oil return passage can reduce suction negative pressure and improve pump efficiency.

However, with a structure in which only one relief port is provided to return the entire amount of oil relieved from the discharge side to the oil suction passage, it is difficult to make the regulator valve compact, especially when the oil temperature is low. When the discharge amount increases in a state where the viscosity of the oil is high, there is a possibility that the excess oil cannot be sufficiently relieved, resulting in an increase in the discharge pressure. In addition, if the relief port is made larger to prevent this kind of situation, the valve body of the regulator valve and the passage area of the oil return passage must also be made larger accordingly, so if the entire oil pump becomes larger, I had a problem.

(Purpose of the invention) In view of the above circumstances, this invention improves the efficiency of the oil pump, maintains the regulator valve etc. in a compact structure, and maintains the discharge amount when the oil temperature is low and the oil viscosity is high. To provide an oil pump for an engine that can sufficiently relieve excess oil even when oil increases.

(Structure of the invention) The present invention provides an oil pump for an engine equipped with a regulator valve that relieves oil from the oil pump discharge side when the oil pump discharge pressure exceeds a predetermined value. is provided with a valve body that slides according to the discharge pressure, and first and second relief ports that are opened and closed by the valve body, and these relief ports are
Arranged at opposing positions around the valve body and at positions offset from each other in the sliding direction of the valve body so that the first relief port opens before the second relief port as the valve body slides. The first relief port is connected to the oil suction passage of the oil pump via an oil return passage formed in the casing of the oil pump, while the second relief port is opened to the outside of the oil pump. .

With this configuration, when the oil pump discharge pressure exceeds a predetermined value, excess oil on the oil pump discharge side is first returned from the first relief port to the oil suction passage through the oil return passage, and if there is a large amount of excess oil, After the oil is returned from the first relief port, the oil is relieved from the second relief port to the outside of the oil pump.

(Example) An example of the present invention will be described based on FIGS. 1 to 3. In these figures, a pump casing 1 is composed of a pump body 2 and a pump cover 3 that covers the front side of the pump body 2, and is attached to a cylinder block (not shown). Inside the pump casing 1, a drive gear 4 driven by an engine output shaft via a transmission mechanism (not shown) and a driven gear 5 meshing with the drive gear are housed. Further, the pump body 2 is formed with an oil suction passage 6 extending from an oil suction port 6a opened at the lower end of one side to an upstream side of both the gears 4 and 5.
An oil discharge space 7 having an oil discharge port 7a is formed on the downstream side of 5. By rotating both the gears 4 and 5 in the directions shown by arrows in FIG. 1, the oil sucked from the oil suction passage 6 is sent to the oil discharge space 7 and is discharged from the oil discharge port 7a. There is.

Further, the pump casing 1 is provided with a regulator valve 8 for adjusting the discharge pressure, and an oil return passage 9 is formed therein. This oil return passage 9 is defined by a partition wall 10 below the gear of the pump body 2, and its downstream end is open to the oil suction passage 6. In this embodiment, oil flows from the oil return passage 9 to the oil suction passage. 6
The oil return passage 9
A downstream end portion of the oil suction passage 6 is opened toward the oil flow direction of the oil suction passage 6 .

As shown in FIG. 2, the regulator valve 8 includes a valve case 11 connected to the pump cover 3 and a valve case 11 formed within the valve case 11 with an inlet end opening into the oil discharge space 7. a plunger-shaped valve body 13 slidably mounted in the passage 12;
a spring 14 biasing toward the inlet side of 2;
The first and second relief ports 15 and 16 are formed on the peripheral wall of the valve body 13 sliding portion of the valve case 11 and are opened and closed by the sliding movement of the valve body 13. Both relief ports 15 and 16 are
The peripheral walls face each other and are offset from each other in the sliding direction of the valve body 13 so that the first relief port 15 opens earlier than the second relief port 16 in accordance with the sliding movement of the valve body 13. It is arranged. Further, the first relief port 15 has a larger diameter than the second relief port 16. The first relief port 15 is located inside the pump cover 3 and is connected to the oil suction passage 6 via the oil return passage 9 by opening toward the upstream end of the oil return passage 9. On the other hand, the second relief port 16 opens on the outer surface side of the pump cover 3.

In the oil pump having such a structure, when the oil discharge pressure in the oil discharge space 7 becomes high, the valve body 13 of the regulator valve 8 slides downward in the figure against the elasticity of the spring 14. move. When the valve body 13 slides to a certain extent, the first relief port 15 is first opened, and excess oil in the oil discharge space 7 is relieved from the first relief port 15. If the increase in discharge pressure cannot be suppressed even in this state, the second relief port 16 is also opened by sliding the pump cover 3 further downward, and the excess oil is drained from the first relief port 15 and the second relief port. Relief from both sides. The oil relieved from the first relief port 15 is returned to the oil suction passage 6 through the oil return passage 9, thereby reducing the suction negative pressure of the oil pump. On the other hand, the oil discharged from the second relief port 16 to the outside of the oil pump is transferred from the lower end of the chain chamber (not shown) in which the oil pump and the chain transmission mechanism are housed to the oil pan (not shown).
will be returned to.

(Effect of the invention) As described above, the oil pump of the invention has two parts arranged at opposing positions around the valve element of the regulator valve and offset from each other in the sliding direction of the valve element.
When the valve body slides as the discharge pressure increases, the oil on the discharge side is first returned from the first relief port to the oil suction passage through the oil return passage, and from the first relief port. Oil that cannot be relieved is relieved to the outside of the oil pump from the second relief port. Therefore, the oil returned from the first relief port to the oil passage reduces the suction negative pressure to increase pump efficiency, and the passage area of the oil return passage is made relatively small.
While maintaining the compact structure of the oil pump including the regulator valve, both of the above relief ports allow excess oil to flow out sufficiently even when the oil temperature is low and the oil viscosity is high and the discharge amount increases. The discharge pressure can be adjusted appropriately. Furthermore, according to this structure, the pressure of the oil flowing out to both the relief ports acts on the valve body in a well-balanced manner, so it is possible to suppress the inclination of the valve body when sliding, thereby reducing the wear of the valve body. It also has the effect of reducing and increasing durability.

[Brief explanation of the drawing]

Fig. 1 is a front view of the entire oil pump showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view taken along the - line in Fig. 1. It is. DESCRIPTION OF SYMBOLS 1... Pump casing, 4... Drive gear, 5... Driven gear, 6... Oil suction passage, 8... Regulator valve, 13... Valve body,
15...first relief port, 16...second relief port.

Claims (1)

[Scope of utility model registration request] In an engine oil pump equipped with a regulator valve that relieves oil from the oil pump discharge side when the oil pump discharge pressure exceeds a predetermined value, the regulator valve includes:
A valve body that slides according to the discharge pressure, and first and second relief ports that are opened and closed by the valve body are provided, and the relief ports are located at opposing positions around the valve body. , and are arranged at positions offset from each other in the sliding direction of the valve body so that the first relief port opens earlier than the second relief port as the valve body slides, and the first relief port is connected to the oil An oil pump for an engine, wherein the oil pump is connected to an oil suction passage of the oil pump through an oil return passage formed in a casing of the pump, and the second relief port is opened to the outside of the oil pump.