JPH0742442U - Internal gear pump - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an internal gear pump that can prevent an increase in power loss of a pump due to an increase in discharge pressure, can be easily installed, and can stabilize the discharge pressure. thing. [Structure] A cylinder 6 provided in a pump body 3 is provided with a valve body 5 that moves in the directions of arrows B ₁ and B ₂ according to the discharge pressure of a discharge port 3B, and when the valve body 5 moves in the direction of arrow B _2. First, the valve body 5 divides the discharge chamber 3D into the first discharge chamber portion 3D-1 and the second discharge chamber portion 3D-2, and the first discharge chamber portion 3D-1 is divided into the first discharge chamber portion 3D-1 and the second discharge chamber portion 3D-2.
The discharge chamber portion 3D-1 is communicated with the bypass passage L ₂ via the communication passages 5B, 5C, 5D.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an internal gear pump, and more particularly to an internal gear pump suitable for supplying lubricating oil to an internal combustion engine for automobiles.

[0002]

[Prior art]

 As a conventional internal gear pump of this type, there is an oil pump described in Japanese Patent Laid-Open No. 5-263770 previously proposed by the present applicant.

Such an oil pump has an inner rotor that rotates while meshing with each other in a pump body (in the publication, “pump casing”) in which a suction chamber communicating with a suction port and a discharge chamber communicating with a discharge port are formed. And the outer rotor, and the inner wall of the pump body separates the discharge chamber into two chambers, the rear side and the front side, in the rotational direction of the rotor, and the first and second discharge ports communicate with each chamber. The relief passage is connected to the second discharge port via a switching valve. In the oil pump having such a structure, when the oil discharge pressure rises excessively, the oil discharged from the second discharge port is released into the relief passage through the switching valve, so that the power loss of the pump is reduced. The increase can be prevented.

[0004]

[Problems to be solved by the device]

 However, in the above-mentioned pump, a switching valve that operates to release the oil discharged from the second discharge port is provided in the middle of the pipe outside the pump body, so it is separate from the holding mechanism for holding the pump body. , Had to have a holding mechanism to hold the switching valve. Further, since the switching valve is turned on and off, the oil discharged from the second discharge port is intermittently released, and the stability of the discharge pressure may be lost.

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 the discharge pressure. To do.

[0006]

[Means for Solving the Problems]

 The internal gear pump of the present invention is an internal gear pump having 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. , A rotation direction of the rotor that is provided on the inner wall of the discharge chamber so as to be movable inward of the discharge chamber and moves inward of the discharge chamber so that the discharge chamber does not communicate with the discharge port. A movable body that can be partitioned into a first discharge chamber section on the front side and a second discharge chamber section on the rear side in the rotational direction of the rotor that communicates with the discharge port, and the movable body is discharged according to the discharge pressure of the discharge port. A drive mechanism that moves inward of the discharge chamber, a bypass passage that communicates between the first discharge chamber portion and the suction port, and a bypass passage that corresponds to the amount of movement of the movable body inward of the discharge chamber. Bypass Characterized by comprising an adjusting mechanism for adjusting the size.

[0007]

[Action]

 The internal gear pump of the present invention includes a moving body that partitions the discharge chamber according to the discharge pressure of the discharge port in the pump body, and a discharge chamber section that is partitioned by the moving body according to the moving amount of the moving body. By adjusting the size of the bypass passage that communicates with the suction port, when the discharge pressure rises, the moving body partitions the discharge chamber and opens the bypass passage, increasing the power loss of the pump due to the rise in discharge pressure. Prevent. Further, by providing the pump body with an operating mechanism such as a moving body, it is possible to easily install the switching valve as an operating mechanism as compared with a conventional one having a switching valve 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]

【Example】

 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 peripheral teeth 1A and inner peripheral teeth 2A mesh with each other, and the inner rotor 1 has O ₁ as a rotation center, and The rotor 2 rotates about O ₂ in the pump body 3 in the direction of arrow A in FIG. The pump body 3 is composed of a pump casing 3-1 as shown in FIG. 1 and a pump cover (not shown) connected to the upper surface of the pump casing 3-1. 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 provided with an intake port 3A for lubricating oil (liquid) for an automobile engine and an oil discharge port 3B. These ports 3A and 3B are provided on the inner wall of the pump casing 3-1. It communicates with the suction chamber 3C and the discharge chamber 3D, which are curved. The oil confining space S is formed by the teeth 1A and 2A located between these chambers 3C and 3D. Therefore, the oil sucked from the suction port 3A by the rotation of the rotors 1 and 2 is confined in the closed space S 1 and then sent under pressure to the discharge port 3B.

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

The tip of the valve body 5 faces the discharge chamber 3D through a radial hole 3G formed in the pump casing 3-1. Further, inside the valve body 5, there is a first communication passage 5B located on the distal end side and penetrating from the center of the valve body 5 in the direction opposite to the arrow A direction, and a valve body located on the proximal end side. A third communication passage 5D penetrating in the radial direction of 5 and a second communication passage 5C which is located at the center and communicates with the first and third communication passages 5B, 5D are formed. 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 returned oil according to the amount of movement of the valve body 5, as described later. The second cylinder chamber R _2, is provided with a spool ring 8 which urges the valve body 5 in the arrow B ₁ direction, the cylinder chamber R ₂ is of the bypass communication path L ₂ to be described later end It is connected to the. The first cylinder chamber R ₁ and the spring 8 constitute a drive mechanism for moving the valve body 5 in the directions of arrows B ₁ and B ₂ as described later.

The suction port 3A has a suction passage L₃ Is connected to the oil pan via the suction passage L₃ In the bypass passage L₂ The other end of is connected. The discharge port 3B has a discharge passage L_Four Is connected to the internal combustion engine via the_Four Is the pressure introduction path L₁ The other end of is connected. Furthermore, the discharge passage L_Four And suction passage L ₃ And a relief passage L provided with a relief valve 9._Five Is connected to the discharge passage L_Four When the oil inside becomes abnormally high in pressure, the relief valve 9 opens to ensure safety.

Next, the operation will be described.

First, in the low-speed rotation range of the engine, the inner rotor 1 and the outer rotor 2 rotate in the direction of arrow A while meshing with each other as the drive shaft 4 rotates at low speed, and their teeth 1A. , 2A, the oil is sucked from the suction port 3A, discharged from the discharge port 3B, and pumped into the engine. At this time, the oil discharge pressure is relatively small, and the valve body 5 in the cylinder 6 is held at the movement limit position in the direction of arrow B ₁ by the urging force of the spring 8, as shown in FIGS. 1 and 2. The tip portion thereof retracts into the hole 3G of the pump casing 3-1, and the opening of the first communication passage 5B is closed by the inner wall of the hole 3G. Therefore, the discharge chamber 3D is communicated with the discharge port 3B over the entire length thereof, and the oil is stably pumped by the volume change between the teeth 1A and 2A in the entire formation range of the discharge chamber 3D.

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 higher than a predetermined value, as shown in FIG. The pressure in the cylinder chamber R ₁ rises and the valve body 5 moves in the direction of arrow B ₂ . Then, the distal end portion of the valve body 5 projects into the discharge chamber 3D, so that the discharge chamber 3D has a front (upstream side) first discharge chamber portion 3D-1 in the arrow A direction and an arrow A direction. In the second discharge chamber 3D-2 on the rear side (downstream side). The opening of the first communication passage 5B of the valve body 5 is located inside the first discharge chamber 3D-1. Therefore, the oil in the first discharge chamber portion 3D-1 is returned from the communication passages 5B, 5C, 5D in the valve body 5 and the second cylinder chamber R ₂ through the bypass passage L ₂ . On the other hand, the oil in the second discharge chamber 3D-2 is discharged from the discharge port 3B, as in the case of the low speed rotation range of the engine described above.

After all, the amount of oil returned from the first discharge chamber portion 3D-1 to the bypass passage L ₂ and the discharge pressure of oil from the discharge port 3B are suppressed, and an excessive increase in pressure in the pump chamber is suppressed. As a result, an increase in pump drive load, that is, power loss is prevented. Further, according to the amount of movement of the arrow B _1, B ₂ direction of the valve body 5, since the opening area of the first communication path 5B in the first discharge chamber portion 3D in the -1 is changed, according to the change The amount of oil returned is adjusted steplessly, that is, the size of the bypass passage L ₂ is adjusted steplessly, and the stability of the discharge pressure is ensured.

The discharge chamber 3D is divided into three or more discharge chamber portions according to the degree of excessive rise in discharge pressure, and the oil in these discharge chamber portions is returned to the bypass passage L _2. May be done. In that case, for example, a plurality of valve bodies 5 may be provided and the valve bodies 5 may be operated according to the degree of excessive rise in the discharge pressure.

[0019]

[Effect of device]

 As described above, the internal gear pump of the present invention is provided with the moving body that partitions the discharge chamber according to the discharge pressure of the discharge port in the pump body, and the moving body partitions the moving chamber according to the moving amount of the moving body. Since the size of the bypass passage that communicates between the discharge chamber and the suction port is adjusted, the discharge chamber is opened by the moving body and the bypass passage is opened when the discharge pressure rises. It is possible to prevent an increase in power loss of the pump due to a rise in pressure, and since the pump body is provided with an operating mechanism such as a moving body, a conventional switching valve as an operating mechanism is provided outside the pump body. In comparison, it can be installed easily. 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.

[Brief description of drawings]

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

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

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

[Explanation of symbols]

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 part 3D-2 Second discharge chamber part 4 Drive shaft 5 Valve body (moving body) 6 Cylinder 7 Plug 8 Spring L ₁ Pressure introduction passage L ₂ Bypass passage L ₃ Suction passage R ₁ First cylinder chamber R ₂ Second cylinder chamber

Claims (2)

[Scope of utility model registration request] 1. An internal gear pump having 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 the suction port and a discharge chamber communicating with the discharge port are formed. The inner wall 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 rotation direction front side of the rotor that does not communicate with the discharge port and a second discharge chamber portion on the rotation direction rear side of the rotor that communicates with the discharge port, A drive mechanism for moving the movable 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 bypass passage communicates with the first discharge chamber portion via a communication passage provided in the moving body, and the adjusting mechanism causes a relative displacement between the moving body and an inner wall of the discharge chamber. The internal gear pump according to claim 1, wherein an opening area of the communication passage in the first discharge chamber portion is adjusted based on the above.