JP2591226Y2 - Internal gear pump - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal gear pump, and more particularly to an internal gear pump suitable for supplying lubricating oil for an internal combustion engine for an automobile.

[0002]

2. Description of the Related Art An oil pump described in Japanese Patent Application Laid-Open No. Hei 5-263770 has been proposed by the applicant of the present invention as a conventional internal gear pump of this kind.

[0003] Such an oil pump includes an inner rotor that rotates while meshing with a pump body (in the publication, a "pump casing") in which a suction chamber communicating with a suction port and a discharge chamber communicating with a discharge port are formed. And an outer rotor. Further, the inner wall of the pump body separates the discharge chamber into two chambers on the rear side and the front side in the rotation direction of the rotor, and the first and second discharge ports communicate with the respective chambers. The relief passage is connected to the second discharge port via a switching valve. With the oil pump having such a configuration, when the discharge pressure of the oil excessively rises, the oil discharged from the second discharge port is released into the relief passage through the switching valve to reduce the power loss of the pump. Can be prevented.

[0004]

However, in the above pump, a switching valve that operates to release oil discharged from the second discharge port is provided in the middle of piping outside the pump body. In addition to the holding mechanism for holding, a holding mechanism for holding the switching valve had to be provided. In addition, since the switching valve performs on and off operations, oil discharged from the second discharge port is intermittently released, and there is a possibility that the stability of the discharge pressure may be lacking.

SUMMARY OF THE INVENTION An object of the present invention is to provide an internal gear pump which can prevent an increase in power loss of a pump due to an increase in discharge pressure, can be easily installed, and can stabilize discharge pressure. It is in.

[0006]

SUMMARY OF THE INVENTION An internal gear pump according to the present invention includes an inner rotor that rotates while meshing with each other in a pump body having a suction chamber communicating with a suction port and a discharge chamber communicating with a discharge port. In an internal gear pump having an outer rotor, the discharge chamber is provided on an inner wall portion of the discharge chamber so as to be movable toward the inside of the discharge chamber, and by moving inward of the discharge chamber, the discharge chamber is A movable body capable of partitioning a first discharge chamber portion on the front side in the rotation direction of the rotor not communicating with the discharge port and a second discharge chamber portion on the rear side in the rotation direction of the rotor communicating with the discharge port, and a discharge pressure of the discharge port; A drive mechanism for moving the movable body inward of the discharge chamber in accordance with the condition, a bypass passage communicating between the first discharge chamber portion and the suction port, and a drive mechanism for moving the movable body inward of the discharge chamber of the movable body. Travel to Depending characterized by comprising an adjusting mechanism for adjusting the size of the bypass passage.

[0007]

[Function] The internal gear pump of the present invention
A movable body that partitions the discharge chamber in accordance with the discharge pressure of the discharge port, and a size of a bypass passage communicating between the discharge chamber portion and the suction port partitioned by the movable body in accordance with the amount of movement of the movable body. When the discharge pressure rises, the discharge chamber is partitioned by the moving body and the bypass passage is opened when the discharge pressure rises, thereby preventing an increase in the power loss of the pump due to the rise in the discharge pressure. In addition, by providing an operating mechanism such as a moving body in the pump body, it is possible to install the switching valve as an operating mechanism more easily than in the conventional case in which a switching valve is provided outside the pump body. Further, the discharge pressure is stabilized by adjusting the size of the bypass passage according to the moving amount of the moving body.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an inner rotor, 2 is an outer rotor, these outer teeth 1A and inner teeth 2A mesh with each other, and the inner rotor 1 is O _1.
And the center of rotation, also the outer rotor 2 as the center of rotation O _2, rotates in the pump body 3 in each direction of arrow A in FIG. The pump body 3 includes a pump casing 3-1 as shown in FIG.
-1 and a pump cover (not shown) coupled to the upper surface. Reference numeral 4 denotes a drive shaft connected to the inner rotor 1, which is rotationally driven by an automobile engine.

The pump body 3 is formed with a lubricating oil (liquid) suction port 3A and an oil discharge port 3B for an automobile engine. These ports 3A and 3B are formed on the inner wall of the pump casing 3-1. It communicates with the suction chamber 3C and the discharge chamber 3D that are formed to be curved. And the teeth 1A, 2 located between these chambers 3C, 3D
A forms a confined space S for oil. Therefore, the oil sucked from the suction port 3A by the rotation of the rotors 1 and 2 is confined in the confined space S, and is then pressure-fed to the discharge port 3B.

The discharge chamber 3 in the pump casing 3-1
The inner wall portion 3E (see FIG. 2) of D extends radially around O ₁ , and extends along the axis O ₃ at the distal end (the upper left end in FIG. 2) of the valve element (moving body) 5. A guide groove 3F is formed for slidably guiding the portion B) in the directions of arrows B ₁ and B ₂ . The valve body 5 is slidably fitted in a cylinder 6 formed on an outer peripheral portion of the pump casing 3-1.
The cylinder 6 extends along the axis O ₃ , and its interior is defined by a piston portion 5A on the base end side of the valve body 5 into first and second cylinder chambers R ₁ and R ₂ . Outer end of the cylinder 6 is closed by a plug 7, a first cylinder chamber R ₁ is connected to one end of the pressure introducing path L ₁ which will be described later.

The distal end of the valve element 5 is connected to a pump casing 3-.
1, and faces the inside of the discharge chamber 3D through the radial hole 3G. Further, inside the valve element 5, a first communication path 5 </ b> B that is located on the distal end side and penetrates from the center of the valve element 5 in the direction opposite to the arrow A direction, 5, a third communication path 5D penetrating in the radial direction, and a second communication path 5C located at the center and communicating between the first and third communication paths 5B and 5D. The first communication passage 5B and the inner wall of the hole 3G of the pump casing 3-1 constitute an adjusting mechanism for adjusting the amount of oil returned according to the amount of movement of the valve body 5 as described later. The second cylinder chamber R _2, a valve body 5 is provided with a spring 8 for biasing the arrow B ₁ direction, the cylinder chamber R ₂ is connected to one end of the bypass passage L ₂ to be described later Have been. The first cylinder chamber R ₁ and the spring 8 constitute a drive mechanism for moving the valve body 5 in the arrow B _1, B ₂ direction as described later.

[0013] suction port 3A is connected to the oil pan through the suction passage L _3, also in its suction passage L _3,
The other end of the bypass passage L ₂ are connected. The discharge port 3B is connected to the internal combustion engine through the discharge passage L _4,
Further, in its discharge passage L _4, the other end of the pressure introduction channel L ₁ is connected. Further, the discharge passage L ₄ and the suction passage L ₃
Between the relief passage L having the relief valve 9
₅ is connected, when the oil in the discharge passage L ₄ is abnormal high pressure, the relief valve 9 is adapted to ensure safety and opening motion.

Next, the operation will be described.

First, in the low-speed rotation range of the engine, with the low-speed rotation of the drive shaft 4, the inner rotor 1 and the outer rotor 2 rotate in the direction of arrow A while meshing with each other, and
When the volume between the teeth 1A and 2A changes, oil is sucked in from the suction port 3A, and the oil is discharged from the discharge port 3B to be pumped into the engine. At that time, the discharge pressure of the oil is relatively small, and the valve body 5 in the cylinder 6 is provided with a spring 8 as shown in FIGS.
Held by the biasing force of the movement limit position of the arrow B ₁ direction, its distal end is regressed bore 3G of the pump casing 3-1, the opening of the first communicating passage 5B is closed by the inner wall of the hole 3G Have been. Therefore, the discharge chamber 3D communicates with the discharge port 3B over its entire length, and the discharge chamber 3D
The oil is stably pumped by the volume change between the teeth 1A and 2A in the entire area of the formation range of D.

Next, in the high-speed rotation range of the engine, when the discharge pressure of the oil from the discharge port 3B rises and becomes equal to or higher than a predetermined value, as shown in FIG.
And the pressure rises in the cylinder chamber R _1, the valve body 5 by the arrow B
Move in _two directions. The distal end portion of the valve body 5 projects into the discharge chamber 3D, so that the discharge chamber 3D is located on the front (upstream) first discharge chamber section 3D-
1 and a second discharge chamber 3D-2 on the rear side (downstream side) in the direction of arrow A. The opening of the first communication passage 5B of the valve element 5 is located in the first discharge chamber 3D-1. Therefore, oil in the first discharge chamber portion 3D-1, the communication passage 5B in the valve body 5, 5C, 5D, and a second from the cylinder chamber R _2, back through the bypass passage L _2. On the other hand, the oil in the second discharge chamber 3D-2 is supplied to the discharge port 3B in the same manner as in the case of the low-speed rotation range of the engine described above.
Is discharged from.

[0017] Finally, an amount corresponding oil returned from the first discharge chamber portion 3D-1 to the bypass passage L _2, discharge port 3B
The pressure of oil discharged from the pump chamber is suppressed, and an excessive increase in pressure in the pump chamber is suppressed, so that an increase in pump driving load, that is, power loss is prevented. The arrow B of the valve element 5
_1, B ₂ direction in response to movement of the first discharge chamber portion 3D-
Since the opening area of the first communication path 5B in the 1 is changed, the returning amount of the oil in accordance with the change is adjusted steplessly, i.e., resulting in the bypass passage L is steplessly size of ₂ , The stability of the discharge pressure is also ensured.

Further, the bypass passage L2 is connected to the discharge chamber 3D.
The oil is returned from the front of the rotors 1 and 2 in the rotation direction, that is, from the first discharge chamber portion 2D-1 near the confined space S, and this effectively reduces the pump driving load, that is, the power loss. Will be prevented. That is, the oil introduced into the discharge chamber 3D from the confined space S is pressurized by the volume change between the outer teeth 1A and the inner teeth 2A due to the rotation of the rotors 1 and 2, and then the discharge port 3B. As shown in FIG. 3, the first discharge chamber portion 2D- on the front side in the rotation direction of the rotors 1 and 2 in the discharge chamber 3D as shown in FIG.
Extracting and returning the oil from 1 means extracting the oil at the initial stage of introduction into the discharge chamber 3D, which is lower than extracting and returning the oil after being pressure-fed to the discharge port 3B as in the relief passage L5. Thus, the flow resistance and the like of oil between the outer teeth 1A and the inner teeth 2A are reduced, so that the pump driving load, that is, the power loss can be more effectively prevented. Furthermore, since the first discharge chamber 2D-1 is formed in the discharge chamber 3D by the valve body 5, the oil in the first discharge chamber 2D-1 can be more reliably extracted and returned. . The discharge chamber 3D may be divided into three or more discharge chambers in accordance with the degree of excessive rise of the discharge pressure, and the oil in those discharge chambers may be returned to the bypass passage L2. In that case,
For example, a plurality of valve elements 5 may be provided, and the valve elements 5 may be operated in accordance with the degree of excessive rise of the discharge pressure.

[0019]

As described above, the internal gear pump according to the present invention has a pump body provided with a movable body that partitions a discharge chamber in accordance with the discharge pressure of a discharge port, and the movable body that moves in accordance with the amount of movement of the movable body. Since the size of the bypass passage communicating between the discharge chamber portion and the suction port partitioned by the moving body is adjusted, the discharge chamber is partitioned by the moving body and the bypass passage is opened when the discharge pressure increases. Thus, it is possible to prevent an increase in the power loss of the pump due to an increase in the discharge pressure, and to provide an operating mechanism such as a moving body in the pump body, so that a switching valve as an operating mechanism is provided outside the pump body. It can be installed more easily than the ones. Further, since the size of the bypass passage is adjusted according to the moving amount of the moving body, the discharge pressure can be stabilized. Furthermore, since the bypass passage extracts oil that is initially introduced into the discharge chamber from the inside of the first discharge chamber on the front side in the rotation direction of the rotor of the discharge chamber and returns the oil to the suction port, the pump drive load, that is, the power loss, is reduced. It can be effectively prevented. In addition, since the first discharge chamber portion is partitioned and formed in the discharge chamber by the moving body, the oil in the first discharge chamber portion can be more reliably extracted and returned.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1 with a part cut away.

FIG. 3 is a plan view of a main part of the moving body shown in FIG. 2 in different moving states.

[Explanation of symbols]

Reference Signs List 1 inner rotor 2 outer rotor 3 pump body 3A suction port 3B discharge port 3C suction chamber 3D discharge chamber 3D-1 first discharge chamber 3D-2 second discharge chamber 4 drive shaft 5 valve body (moving body) 6 cylinder 7 plug 8 spring L ₁ the pressure introduction channel L ₂ bypass passage L ₃ suction passage R ₁ first cylinder chamber R ₂ the second cylinder chamber

Claims (2)

(57) [Scope of request for utility model registration] 1. An internal gear pump comprising: an inner rotor and an outer rotor that rotate while meshing with each other in a pump body in which a suction chamber communicating with a suction port and a discharge chamber communicating with a discharge port are formed. The inner wall portion of the chamber is provided movably toward the inside of the discharge chamber, and by moving inward of the discharge chamber,
A movable body capable of partitioning the discharge chamber into a first discharge chamber portion on the front side in the rotation direction of the rotor not communicating with the discharge port and a second discharge chamber portion on the rear side in the rotation direction of the rotor communicating with the discharge port; A drive mechanism for moving the moving body inward of the discharge chamber in accordance with the discharge pressure of the discharge port; a bypass passage communicating between the first discharge chamber portion and the suction port; An internal gear pump, comprising: an adjusting mechanism that adjusts the size of the bypass passage according to the amount of movement. 2. The apparatus according to claim 1, wherein the bypass passage communicates with the first discharge chamber via a communication passage provided in the moving body, and the adjusting mechanism controls a relative displacement between the moving body and an inner wall of the discharge chamber. The internal gear pump according to claim 1, wherein the opening area of the communication passage in the first discharge chamber portion is adjusted based on the following.