JP2527249Y2 - Oil pump - Google Patents

Description

The present invention relates to an improvement in an oil pump that supplies lubricating oil to each sliding portion of an internal combustion engine, for example.

2. Description of the Related Art Conventional oil pumps of this type include, for example,
A so-called trochoid type described in JP-A-61-171885 is known.

In brief, the oil pump is rotatably housed in a pump casing having a body and a cover for closing one end opening of the body, and a pump chamber in the pump casing meshing with internal and external teeth. And a drive shaft that penetrates a substantially central portion of the pump casing, is connected to the inner rotor, and receives a driving force from a crankshaft. Further, on one side of the pump chamber of the pump casing, a suction chamber and a discharge chamber in which both side surfaces of the inner and outer teeth face respectively are casing. Further, a spigot flange is formed on one inner peripheral edge of the inner rotor so as to fit into a fitting hole formed in the inner peripheral surface of the body.

With the rotation of the drive shaft, the inner rotor and the outer rotor rotate in the same direction, and lubricating oil is sucked into a space portion (volume portion) for one tooth formed between the inner and outer teeth. Accordingly, the space changes in volume and discharges the lubricating water from the discharge port.

Problems to be Solved by the Invention Incidentally, in such a conventional oil pump, the inner rotor and the outer rotor rotate in the pump chamber via a minute gap between both side surfaces of each rotor, the body, and the cover. It has become. Therefore, when the accuracy of the gaps is reduced due to errors in manufacturing and assembling the pump casing, the rotors, and the like, the behavior of the rotors becomes unstable. It rotates while biasing toward the body side where the spigot flange is located. Therefore, the gap between the cover and one side surface of each rotor becomes relatively large. As a result, a large amount of the lubricating oil discharged from the discharge chamber leaks from the gap to the outside, resulting in a decrease in pump efficiency. In addition, during the rotation of each rotor, micro-vibration is caused in the axial direction (the body side and the cover side), and there is a possibility that both side surfaces are worn and the gap portions are further increased.

Means for Solving the Problems The present invention has been devised in view of the conventional problems, and the invention according to claim 1 has an inside of a pump casing including a body and a cover for closing an open end of the body. To
An inner rotor and an outer rotor that meshes with the inner rotor are rotatably housed, and a pair of discharge chambers are formed on opposing surfaces of the body and the cover, with both side surfaces of the inner rotor facing each other, and a body side of the inner rotor. In an oil pump having a spigot flange protruding from the inner peripheral edge of one side surface, the pressure receiving area facing the one discharge chamber on one side surface of the inner rotor on the spigot flange side is the other of the other side surface opposite to the one side surface. It is characterized in that it is set larger than the pressure receiving area facing the discharge chamber.

The invention according to claim 2 provides a pump casing comprising a body and a cover for closing an open end of the body,
An inner rotor and an outer rotor meshing with the inner rotor are rotatably housed, and discharge chambers are formed on opposing surfaces of the body and the cover so that both side surfaces of the inner rotor face each other, and a cover-side other end surface of the inner rotor. In the oil pump having a spigot flange projecting from the inner peripheral edge of the inner rotor, the pressure receiving area facing the other discharge chamber on the other spigot flange side of the inner rotor is reduced by one discharge chamber on one side opposite to the other side. It is characterized in that it is set to be larger than the pressure receiving area facing.

According to the first aspect of the invention, during rotation of the inner and outer rotors, the positive pressure in one of the discharge chambers acts on one side of the inner rotor facing one of the discharge chambers more than the other side. Therefore, the inner rotor is pushed in the cover direction opposite to the side on which the spigot flange formed on the body side is formed, and the cross-sectional area of the gap formed between the inner surface of the cover and the other surface of the inner rotor is increased. Can be made smaller.

In the invention according to claim 2, since the inner flange of the inner rotor is formed on the cover side, contrary to the invention of claim 1, the inner rotor is caused by a large discharge pressure of the other discharge chamber facing the other side surface. The cross-sectional area of the gap portion which is pressed in the body direction and formed between the inner side surface of the body and one side surface of the inner rotor can be reduced as much as possible.

According to a third aspect of the present invention, there is provided a pump casing comprising a body and a cover for closing an open end of the body,
An inner rotor and an outer rotor meshing with the inner rotor are rotatably housed, and a pair of suction chambers are formed on opposing surfaces of the body and the cover, with both side surfaces of the inner rotor facing each other, and a body side of the inner rotor. In an oil pump having a spigot flange protruding from the inner peripheral edge of one side surface, the pressure receiving area facing the other suction chamber on the other side opposite to the spigot flange of the inner rotor is set to one side of the spigot flange side. It is characterized in that it is set to be larger than the pressure receiving area facing the suction chamber.

The invention according to claim 4 is such that, inside a pump casing comprising a body and a cover for closing an open end of the body,
An inner rotor and an outer rotor meshing with the inner rotor are rotatably housed, and suction chambers are formed on opposing surfaces of the body and the cover so that both side surfaces of the inner rotor face each other, and a cover-side other end surface of the inner rotor. In the oil pump having a spigot flange protruding from the inner peripheral edge of the inner rotor, the pressure receiving area facing the one suction chamber on one side of the spigot flange side of the inner rotor is reduced by the other suction at the other end face opposite to the one side. It is characterized in that it is set larger than the pressure receiving area facing the chamber.

According to the third aspect of the invention, while the inner and outer rotors are rotating, the suction negative pressure in the suction chamber acts on the other side of the inner rotor facing the other suction chamber more than one side. Therefore, the inner rotor is pushed in the direction of the cover opposite to the side on which the spigot flange formed on the body side is formed, thereby increasing the cross-sectional area of the gap formed between the inner side surface of the cover and the other side surface of the inner rotor. Can be made smaller.

According to the second aspect of the present invention, since the inner flange of the inner rotor is formed on the cover side, contrary to the third aspect, the inner rotor has a large suction negative pressure in one suction chamber facing one side. As a result, the sectional area of the gap formed between the inner side surface of the body and one side surface of the inner rotor can be reduced as much as possible.

Embodiment An embodiment of the present invention will be described below in detail with reference to FIGS.

That is, this oil pump is applied to a trochoid type as in the prior art, and 1 is a pump casing provided with a body 2 and a cover 3 for closing an open end of the body 2, and 4 is a pump casing. A circular pump chamber 5 formed inside the casing 1 is a drive shaft penetrating the center of the pump chamber 4, and 6 a, 6 b, 7 a, and 7 b are lubricating oil pumps disposed substantially on both left and right sides of the pump chamber 4. A suction port 6c and a discharge port 7c are connected to each end of the oil suction chamber and the discharge chamber, and the suction chambers 6a and 6b and the discharge chambers 7a and 7b. Reference numerals 8 and 9 denote an inner rotor and an outer rotor rotatably housed in the pump chamber 4. The inner rotor 8 connected to the drive shaft 5 has an inner peripheral surface on one side edge of the body 2 side. An annular spigot flange 10 that fits into an annular fitting hole 2a provided on the inner peripheral edge is integrally casingd, and a plurality of external teeth 8a are formed on the outer periphery. On the other hand, the outer rotor 9 has an annular shape, the center of which is eccentric from the center of the inner rotor 8 by a predetermined amount, and the inner periphery of which forms one space 11 while meshing with the external teeth 8a. Are formed.

Further, on the outer peripheral side of the fitting hole 2a of the body 2, an intermittent annular suction chamber 6a-side first seal portion 12 slidably in contact with one side surface 8b of the inner rotor 8 on the side of the flange 10 and a discharge chamber 7a.
The second side seal portion 13 is formed. Meanwhile, cover 3
On the inner peripheral surface 3a, an intermittent annular suction chamber 6b-side third seal portion 14 and a discharge chamber 7b-side fourth seal portion 15 that are in sliding contact with the other side surface 8c of the inner rotor 8 are formed. As shown in FIG. 1, the first seal portion 12 has a third width in the radial direction.
The area ratio (pressure receiving area) formed larger than that of the seal portion 14 and facing the suction chamber 6a on one side surface 8b of the inner rotor 8.
The area ratio (pressure receiving area) of the other side 8c facing the suction chamber 6b is larger than that of the other side 8c, that is, the pressure receiving area receiving suction negative pressure from the suction chambers 6a and 6b is set to be larger on the other side 8c than on one side 8b. Have been. The fourth seal portion 15 is formed so that its width in the radial direction is larger than that of the second seal portion 13 so that one side surface 8b is closer to the discharge chamber 7a than the other side surface 8c of the inner rotor 8. The area ratio that faces is large, that is, the discharge chambers 7a and 7
The pressure receiving area for receiving the positive discharge pressure in b is set to be larger on one side surface 8b than on the other end side 8c.

Therefore, according to this embodiment, when the inner shaft and the outer rotor 8, 9 rotate in the same direction while meshing with each other with the rotation of the drive shaft 5, and the pumping operation is performed in the pump chamber 4, the inner rotor 8 sucks. On the side of the chambers 6a and 6b, the suction negative pressure acts more on the side of the other side 8c than on the side of the side 8b to attract the other side 8c to the inner peripheral surface 3a of the cover 3, while on the side of the discharge chambers 7a and 7b, The positive discharge pressure acts on the one end face 8b side more than the other side face 8c, and the other side face 8c is
Press against the inner surface 3a of the. For this reason, the inner rotor 8
Are always located at the center of the pump chamber 4 or near the cover 3 side during the rotation operation, and the other side surface 8c of the inner rotor 8
And the gap between the end face of each of the seal portions 14 and 15 of the cover 3 can be made as small as possible. As a result, the discharge chamber
Leakage of the lubricating oil discharged from 7b from the gap can be sufficiently prevented, and the behavior of the inner rotor 8 and the outer rotor 9 can be stabilized.

Note that the present invention is not limited to the configuration of the above-described embodiment, and when the formation position of the inlay flange 10 is on the other side surface 8c side of the inner rotor 8, the seal portions 12, 13, 1
What is necessary is just to set the radial width dimension of 4,15 in reverse. As a means for changing the size of the pressure receiving area, as described above, it is not always necessary to use the respective seal portions 12 to 15 on the inner peripheral side of each body 2 and the cover 3, but it is also possible to use the seal portions on the outer peripheral side. is there.

Further, the oil pump of the present invention can be applied to, for example, a power steering pump.

Advantageous Effects of the Invention As is apparent from the above description, according to the oil pump of the present invention, the side face of the inner rotor on which the inlay flange is formed is caused by relatively high discharge pressure or suction negative pressure. Since the inner rotor is pressed or sucked in the direction opposite to the inner flange side, the inner rotor is pressed toward the inner surface of the cover or body opposite to the inner rotor flange of the inner rotor, and the inner surface of the cover or body and the inner rotor flange of the inner rotor. The cross-sectional area of the gap between the side surface on which is not formed can be reduced as much as possible. As a result, leakage of the liquid from the gap is sufficiently prevented, and a decrease in pump efficiency can be suppressed.

In addition, the axial vibration of the inner rotor during the rotation operation is prevented, and wear on both side surfaces of the inner rotor and the inner surface of the pump casing is sufficiently prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line II of FIG. 2 showing an embodiment of the oil pump according to the present invention, FIG. 2 is a view taken along line II-II of FIG. 1, and FIG. FIG. 3 is a view taken in the direction of arrows III-III in FIG. 1 ... Pump casing, 2 ... Body, 3 ... Cover, 6a, 6b ... Suction chamber, 7a, 7b ... Discharge chamber, 8 ... Inner rotor, 8b ... One side, 8c ... Other side, 9 …… Outer rotor, 10 …… Inlay flange.

Claims (4)

(57) [Scope of request for utility model registration] 1. An inner rotor 8 and an outer rotor 9 meshed with the inner rotor 8 are rotatably housed in a pump casing 1 comprising a body 2 and a cover 3 for closing an open end of the body 2. A pair of discharge chambers 7a and 7b are formed on opposite surfaces of the body 2 and the cover 3 so that both side surfaces of the inner rotor 8 face each other. An inner flange 10 is formed on an inner peripheral edge of one side surface 8b of the inner rotor 8 on the body 2 side. The pressure receiving area facing the one discharge chamber 7a of the one side surface 8b of the inner rotor 8 side of the inner rotor 8 is set to the other discharge chamber of the other side surface 8c opposite to the one side surface 8b. An oil pump characterized in that it is set larger than the pressure receiving area facing 7b. 2. An inner rotor 8 and an outer rotor 9 meshing with the inner rotor 8 are rotatably housed in a pump casing 1 comprising a body 2 and a cover 3 closing an open end of the body 2. Discharge chambers 7a and 7b are formed on opposing surfaces of the body 2 and the cover 3 so that both side surfaces of the inner rotor 8 face each other.
An oil pump having an inlay flange protruding from the inner peripheral edge of the other end surface 8c of the cover 3 side of the inner rotor 8, the pressure receiving area facing the other discharge chamber 7 b of the other side surface 8 c of the inner rotor 8 on the other side of the inner rotor 8 An oil pump characterized in that it is set larger than a pressure receiving area facing one discharge chamber 7a of one side surface 8b on the opposite side to the one. 3. An inner rotor 8 and an outer rotor 9 meshed with the inner rotor 8 are rotatably housed in a pump casing 1 comprising a body 2 and a cover 3 closing an open end of the body 2. A pair of suction chambers 6a and 6b are formed on opposite surfaces of the body 2 and the cover 3 so that both side surfaces of the inner rotor 8 face each other. An inner flange is formed on an inner peripheral edge of one side surface 8b of the inner rotor 8 on the body 2 side. In the projecting oil pump, the pressure receiving area facing the other suction chamber 6a on the other side face 8c of the inner rotor 8 opposite to the spigot flange 10 is reduced by one suction chamber 6b on one side face 8b of the spigot flange 10 side. An oil pump characterized in that it is set to be larger than the pressure receiving area facing the oil pressure. 4. An inner rotor 8 and an outer rotor 9 meshing with the inner rotor 8 are rotatably housed inside a pump casing 1 comprising a body 2 and a cover 3 closing an open end of the body 2. Suction chambers 6a and 6b are formed on opposite surfaces of the body 2 and the cover 3 so that both side surfaces of the inner rotor 8 face each other.
The inner surface of the other end surface 8c of the cover 3 is provided with an inlay flange protruding therefrom. The pressure receiving area of the one side surface 8c of the inner rotor 8 facing the one suction chamber 6b is reduced by the one side surface. An oil pump characterized in that it is set larger than the pressure receiving area facing the other suction chamber 6a of the other end surface 8c on the opposite side to 8b.