JPS61212680A - Gear pump - Google Patents

Abstract

PURPOSE:To enable the discharge rate of gear pump to change easily by shifting the gear in the axial direction so as to change the breadth of engagement of gear, and by filling supplementary substance in the void formed behind the rear face of gear at the time. CONSTITUTION:The driven gear 13 of a gear pump is supported by a casing so as to be movable in the axial direction, and on the rear face part of this gear 13 a side plate 29 which is energized by a spring 33 and a void 27 is formed. Since the driven gear 13 moves in the axial direction against the spring- back force when oil pressure is applied on the shaft 5 of the driven gear 13 through an oil passage 37, the breadth of engagement of the driven gear 13 with a driven gear 7 becomes narrow, and accordingly the discharge rate decreases.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gear pump used for lubricating an automobile engine.

[Technical Background and Problems] As a conventional gear pump of this type, there is one shown in FIG. 4, for example. That is, the input shaft 3 is rotatably supported by the case 1, and the idle shaft 5 is fixedly supported.

A drive gear 7 is fixed to the input shaft 3 by a key 9, and an input gear 11 meshed with an output gear on the engine side (not shown) is fixed to the outer end of the input shaft 3. Further, a driven gear 13 is rotatably supported on the idle shaft 5.

On the other hand, a bypass passage 17 communicating with an oil pan (not shown) is formed in the discharge passage 15 of the case 1, and this bypass passage 17 includes a sleeve 19 and a check spring 2.
A relief valve 23 consisting of 1 is interposed.

When the engine is started, the drive gear 7 and driven gear 13 rotate via the input gear 11 and input shaft 3, and oil is sucked from an oil pan (not shown) and discharged from the discharge passage 15.

If the pump discharge pressure rises too much, the relief pulp 23
Due to this action, excess oil is returned from the bypass passage 17 to the oil pan. Therefore, the amount of oil discharged is regulated by the discharge pressure of the pump.

However, in such a structure, since the discharge capacity of the gear pump itself does not change, the engine output is lost by the amount of oil returned by the relief valve 23, which may adversely affect engine fuel efficiency.

On the other hand, there is a method disclosed in Japanese Utility Model Application Publication No. 58-129015, for example. This uses an auxiliary transmission to shift the input to the input gear 11 when the engine speed exceeds a specified value, but the structure becomes complicated and the cost increases due to the provision of the auxiliary transmission. There is a risk that it will become.

[Objective of the Invention] This invention was devised in view of the above-mentioned problems, and it is possible to reduce drive loss by regulating the discharge amount for input rotations greater than or equal to - chamber while suppressing the complexity of the structure and high cost. The purpose of the present invention is to provide a gear pump that can achieve the following.

[Structure of the Invention] In order to achieve the above object, the present invention provides a gear pump having a pair of gears that are supported in a case and mesh with each other, the gear pump having the pair of gears,
supporting at least one of the pair of gears so as to be movable in the axial direction, and providing a gap in the case that allows the gear to move;
Furthermore, a mechanism for applying a driving force for axial movement and return of the gear, and a compensating member that follows the gear when the gear moves and fills the space formed by the misalignment of the gear during movement. This is a gear pump with special features.

[Example] Hereinafter, the present invention will be explained in detail based on FIGS. 1 to 3. This embodiment has a case 1, an input shaft 3, an idle shaft 5, a drive gear 7, a key 9, an input gear 11, a driven gear 13, and a discharge boat 15, similar to the conventional example shown in FIG. . Since these details have already been explained, they will be omitted.

FIG. 1 shows a first embodiment of the present invention, in which the meshing of gears is shifted by moving an idle shaft 5 in the axial direction using hydraulic pressure.

A gap 25, 27 and a compensating member 31 are provided on both sides of the driven gear.

The cavity 27 on one side has an inner circumferential diameter slightly larger than the outer diameter of the driven gear 13, allowing the driven gear 13 to enter therein. The gap portion 27 on the opposite side has an inner circumferential diameter that is approximately the same as the tip circle diameter of the driven gear in the area that faces only the driven gear 13, and a portion that faces the area where the drive gear 7 meshes with the teeth of the drive gear. An arc-shaped notch with a radius slightly larger than the radius of the tip is provided, and a supplementary member 31 having a notched circular shape as shown in FIG. 3 is housed in this notch.

Next, a plate 29 inscribed in the cavity 27 is provided.
As an elastic body, for example, a disc spring 33 is prepared and accommodated in the cavity 27, and one side of the driven gear 13 is pressed by the disc spring 33 via the plate 29. On the other hand, one end of the idle shaft 5 is formed to be pressed through a hydraulic pressure introduction port 37. The oil pressure may be applied from the outside, or may be applied using pressure from a main gear rally (not shown).

It should be noted that, for example, when the elastic force of the disc spring 33 exceeds the appropriate pressure value of the pressure shaft in the main gear rally, the compensating member 31, which is the hydraulic piston, moves the driven gear 13, and when the elastic force falls below the appropriate pressure value, the driven gear 13 moves. is set to return. Further, for such a setting, an adjustment bolt may be provided in the case 1 so that the disk spring 33 can be attached to the gear pump and finely adjusted from the outside of the pump case 1.

In the gear pump configured as described above, for example, when the hydraulic pressure of the operating pressure oil main gear rally exceeds the appropriate value, this pressure is fed back to the gear pump and applied to the compensation member 31, overcoming the elastic force of the disc spring 33 and causing the driven gear to move. 13 is moved to the left side of the concave surface, the meshing width with the drive gear 7 is reduced, and an increase in the oil supply layer is suppressed, and the discharge amount of the gear pump is reduced accordingly.

In the above example, the idle shaft 5 and the driven gear 13 are fixed together, and the axial movement is performed by applying hydraulic pressure to the end of the idle shaft 5. However, as shown in FIG. 2, the supplementary member 31 is used as a hydraulic piston. It may be activated.

Note that the above-mentioned movement of the driven gear may be performed by electromagnetic force instead of hydraulically. That is, driven gear 1
3 and the idle shaft 5 are fixed at least in the axial direction, so that they can move in the axial direction in an integrated state,
One end of this shaft is directly extended and protruded outward from the case 1, or the spindle is protruded outward through an intermediate spindle.

A solenoid electromagnetic mechanism is connected to the above-mentioned protruding shaft or protruding spindle, and a pressure detection device is provided on the pressure oil main gear rally, which is then wired to the solenoid electromagnetic mechanism via a control device to keep the oil pressure of the main gear rally constant as described above. It is possible to cause the operation to change the meshing width of the gears so that

Instead of feeding back or detecting the oil pressure from the main gear rally, it is also possible to feed back or detect the oil pressure from the discharge passage of the gear pump.

[Effects of the Invention] As is clear from the above, according to the configuration of the present invention, when the gear is moved to change the meshing width of the gear, at the same time, the gap created at the back of the gear is almost filled with the compensation member. Because of this, it is possible to regulate the discharge amount of the gear pump in an extremely stable manner against rotational inputs greater than or equal to - chamber, and it is possible to efficiently reduce drive loss. Since the structure is not used, it is possible to control the complexity of the structure and increase the cost, and it is also possible to make the structure more compact.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a first embodiment of the invention, FIG. 2 is a vertical cross-sectional view of the second embodiment, FIG. 3 is a front view of some of the components of these devices, and FIG. FIG. 2 is a vertical cross-sectional view of a conventional example. 1... Case 13... Driven gear (gear) 27... Gap portion 29... Complementary member 31.
...Replacement component patent applicant Tochigi Tomito Sangyo Co., Ltd. No. 1m

Claims (1)

[Claims] A gear pump having a pair of gears supported in a case and meshing with each other, at least one of the pair of gears is supported movably in the axial direction, a gap is provided in the case to allow movement of the gear, and further A mechanism for applying a driving force for axial movement and return of the gear, and a compensating member that moves to follow the gear when the gear moves and fills the space formed by the misalignment of both gears. A gear pump characterized by: