JPS61265372A - Low pressure lubricating device for gear pump - Google Patents

Abstract

PURPOSE:To increase load capacity in the bearing of a gear shaft as well as to improve the extent of durability in the bearing, by letting a tooth space flow oil in this tooth space immediately after passing through a suction port back to the suction port side by way of the circumference of the gear shaft. CONSTITUTION:Concave parts 16 and 17 are formed in a side plate facing the tooth space of tooth spaces G1 of gears 2 and 3 immediately after passing through a suction port 18, and these concaves parts 16 and 17 are interconnected to oil grooves 14 and 15 being formed in shaft holes 12 and 13 via annular grooves 19 and 20 formed in a boundary part between these gears 2, 3 and gear shafts 14 and 15. Since these oil grooves 14 and 15 are interconnected to the side of the suction port 18 via clearances 21 and 22 between the gear shaft and a mounting flange (m) and a notch part 23, if high pressure oil at the side of the tooth space G2 is penetrated into the tooth space G1, this pressure oil lubricates a bearing part in low pressure and then flows back to the suction port side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low-pressure lubricating device that lubricates a gear shaft portion using low-pressure oil flowing in from a suction port.

[Prior Art] As a conventionally known low-pressure lubricating device, there is one in which the exit side of a lubricating flow path is opened in an expansion chamber that expands the capacity of a meshing portion during the rotation process of the gear. and,
In this device, negative pressure is created when the expansion chamber expands, and the effect of this negative pressure is utilized to suck out lubricating oil from the outlet side of the lubricating flow path.

(Problems to be solved by the present invention) In this conventional device, since the exit side of the lubrication flow path is made negative pressure, the range in which the oil film is formed in the bearing section becomes narrow, and the bearing load capacity decreases accordingly. There was a problem.

An object of the present invention is to provide a device in which a sufficient bearing load capacity can be obtained by enlarging the oil film formation range by injecting low-pressure oil into the lubricating flow path.

Furthermore, another object of the present invention is to provide a device that ensures the supply amount of lubricating oil according to the discharge pressure of the gear pump.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides bushings or side plates on the sides of a pair of gears, and supplies pressure oil to the backs of the bushings or side plates to balance the loading force. In a gear pump, this is the position of the tooth groove where communication with the suction boat is cut off at the moment the tooth groove passes the suction boat during the rotation process of the gear, with the tip extending slightly outward from the tooth bottom radius. A lubricating flow path is formed in which a recess is formed and a flow path is formed in which the low-pressure oil that has flowed into the recess is circulated back to the suction boat via the periphery of the gear shaft.

(Operation of the present invention) With the above structure, the tooth grooves corresponding to the recesses are filled with low-pressure oil, but on the other hand, high-pressure oil leaking from the tooth tip gaps flows into the tooth grooves.

When high-pressure oil flows in from the gap between the tooth tips in this way, the low-pressure oil that filled the tooth groove is pushed out into the recess by the action of the high-pressure oil and is supplied to the lubricating flow path.

(Effects of the present invention) According to the device of the present invention, the low pressure oil in the tooth groove is supplied to the lubricating flow path by the action of the high pressure oil flowing into the tooth groove.
Sufficient lubricating oil can be secured without using negative pressure like in the past.

Also, as mentioned above, since the action of high pressure oil flowing from the tooth tip gap is utilized, the amount of leakage from the gear tooth tip, that is, the flow rate of high pressure oil flowing into the tooth groove, is the discharge of the gear pump. Increases in proportion to pressure. In other words, the higher the discharge pressure, the more low-pressure oil is supplied to the lubrication flow path, and therefore the lubricant can be secured in accordance with the discharge pressure of the gear pump.

(Embodiment of the present invention) A main body a has both sides thereof closed with a cover C and a mounting flange m, and a pair of gears 2.3 is installed inside a pore 1 formed in the main body a. Axis 4~
7 is supported by bushes 8-11.

Note that the bushes 8.9 and 10.11 form a pair, and the configurations of the bushes 8.9 side and the bushes 1o and 11 side are substantially the same.
Only the configuration on the ll side will be explained.

The bushing 10.11 made as above is the gear shaft 6.7.
This is a shaft hole 12.13 into which a shaft is inserted, and an oil groove 14.15 is formed in the axial direction of the shaft hole 12.13.

Furthermore, this bushing 10.11, the gear 2.3
Recesses 16 and 17 are formed on the side surface that comes into contact with the
These recesses 1G and 17 are formed at the moment when the tooth groove passes through the suction port 1B during the rotation process of the gear 2.3.

It opens into the tooth groove Gl where communication with the suction bow 18 is cut off. Moreover, the tips of the four parts 1B and 17 are located slightly outward from the tooth bottom radius.

The recessed portion 18.17 is configured to communicate with the oil groove 14.15 via an annular groove 19.20 formed at the boundary between the gear 2.3 and the gear shaft 6.7.

Oil groove 14.1 communicating with recess 16.17 in this way
5 communicates with the suction boat 18 side via a gap 21.22 formed between the terminal end of the gear shaft 6.7 and the mounting flange m and a notch 23 formed in the main body a. is the lubricating flow path of the present invention.

In addition, the reference numeral 24 in the figure is a sealing member provided on the back surface of the bushing 10.11, and the sealing member 24 divides the back surface side of the bushing 1O111 into a high pressure area H and a low pressure area L.

When the gear 2.3 is rotated in the direction of the arrow 25 in FIG. It is discharged from.

When high-pressure oil is discharged from the discharge port 26 as described above, the high-pressure oil leaks from the tooth groove on the high-pressure side toward the tooth groove on the low-pressure side through the gap between the tooth tips of the gears 2 and 3. become. The amount of leakage increases in proportion to the discharge pressure and the viscosity of the hydraulic fluid.

When considering the amount of leakage and paying attention to the tooth groove G1 in FIG. 2, it is clearly seen that the low pressure oil trapped in the tooth t+9t G + is forced into the recesses 1B and 17.

That is, at the tooth groove G1 position, at the moment when communication with the suction port 18 is cut off, the tooth groove G1 is filled with low-temperature, low-pressure oil.

On the other hand, high-pressure oil from the adjacent tooth groove G2 also flows into this tooth groove G1 through the tooth tip gap.

When high pressure oil from the tooth groove G2 side flows into the tooth groove Gl, the tooth groove 0
The low-pressure oil in 1 is forced into the recess 18.17 under the action of this high-pressure oil. The low-temperature, low-pressure oil pushed into the recess 18.17 in this way flows from the annular groove 19.20 to the oil groove 14.
15→gap 21, 22→pass through the notch 23 and return to the suction port 18. In other words, the low pressure oil forced into the recesses 16, 17 flows through the lubricating flow path of the present invention.

The flow rate of the lubricating oil is determined in proportion to the flow rate and viscosity of the high pressure oil flowing into the tooth space Gl. Therefore, the higher the discharge pressure of the gear pump, the larger the flow rate of the low-pressure lubricating oil can be ensured, the more the oil film formation range can be expanded, and the bearing load capacity can be increased accordingly.

In the above embodiment, bushings are provided on both sides of the gear 2.3, but it goes without saying that side plates may be used in place of the bushings.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view, and FIG. 2 is a sectional view taken along the line ■--■ in FIG. 2.3... Gear, 4-7fI axle, 8-11... Bush, 16.17... Recess, 18... Suction port, G1... Tooth groove.

Claims (1)

[Claims] In a gear pump that has bushes or side plates on the sides of a pair of gears and supplies pressure oil to the backs of the bushes or side plates to balance the loading force, the moment the tooth groove passes through the suction port during the rotation process of the gears, At the tooth groove position where communication with the suction port is cut off, a recess is formed with the tip located slightly outward from the tooth bottom radius, and the low pressure oil that flows into this recess is directed around the gear shaft. A gear pump low-pressure lubrication device that forms a lubrication flow path that circulates the flow back to the suction port side via the lubrication flow path.