JPH02286889A - Gear pump - Google Patents

Abstract

PURPOSE:To lessen variation in the oil pressure and reduce noise and vibration by adhering a damper material made of compressively elastical substance to the non-contact side of each cog of at least one of a pair of gears meshing with each other. CONSTITUTION:Because the driving gear 2 nd follower gear 3 of a gear pump 1 rotate only in respective determined directions, cogs 2a..., 3a... of the two gears contact each other only by their one sides. Damper material 35... made of compressively elastical substance is adhered to that surface of each cog which is free of contacting. Even though oil in the gap 36 contracts or expands while encapsulated by the two cogs, it is absorbed by the damper material 35, that should suppress possible pressure variation to low level. Thus noise and vibration can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to the structure of a gear pump used in construction machinery, machine tools, agricultural machinery, etc.

[Prior Art] In a gear pump that has a pair of gears that mesh with each other, some of the oil carried to the discharge port side by the rotation of the gears is trapped in the gap between the teeth of both gears and returned to the original suction port side. A confinement phenomenon occurs in which the oil is returned to the oil, but as the oil is repeatedly compressed and
This causes problems such as vibration, noise, and air bubbles in the oil.

In order to avoid this, a fourth
Relief yt32 and 33 as shown in the figure or FIG. 5 are provided to reduce oil pressure fluctuations.

[Problem to be solved by the invention] However, since leakage occurs due to machining errors and deformation due to loads, it is difficult to solve the phenomenon of confinement to some extent, and there is a problem in that vibration and noise are actually generated. Ta.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration.

In other words, a gear pump according to the present invention has a pair of gears that mesh with each other, and a buffer material made of a compressible elastic body is provided on the non-contact surface side of the teeth of at least one of the pair of gears. It is characterized by being pasted.

[Function] Since a cushioning material made of a compressible elastic material is attached to the non-contact surface side of the teeth of a pair of gears meshing with each other, the compression and expansion of oil due to the above-mentioned confinement phenomenon is absorbed by the cushioning material. As a result, fluctuations in the pressure of the oil present in the gap between the pair of gears are reduced, resulting in less vibration and noise.

[Embodiment] The external gear pump 1, which is an embodiment of the present invention shown in FIGS. is housed in. The case 5 is composed of a case body 5a and a front cover 5b, both of which are fixed with a port 8. One shaft 11 of the drive gear 2 is inserted into the bearing hole 1 of the front cover 5b.
3 through a bushing 14, and the other shaft 15 is supported through a bushing 14 in a shaft hole bearing 17 of the case body 5a. The shaft 11 projects outward from the front cover 5b and has an oil seal 20 fitted in the opening 19.
is sealed by.

Further, the shafts 22 and 23 on both sides of the driven gear 3 are connected to bearing holes 24 and 23 formed in the front cover 7 and the case body 5a.
is supported through bushings 14 and 14. Side plates 27 and 28 are interposed between both side surfaces of the driving gear 2 and the driven gear 3 and the inner surface of the case 5.

The gear chamber 6 has a constricted central portion along the outer diameter of the drive gear 2 and driven gear 3 that mesh with each other, and a high-pressure side discharge port 30 that communicates with the front cover 5b at the constricted portion. A suction port 31 on the low pressure side is provided. When the drive gear 2 rotates in a predetermined direction (clockwise in FIGS. 2 and 3), the driven gear 3 rotates in the opposite direction, and the oil sucked in from the suction port 31 flows onto the wall of the gear chamber 6. It is sent to the discharge port 30 side along. As shown in FIG. 3, relief grooves 32 and 33 are provided in the side plates 27 and 28 on both sides of the meshing portion of both gears 2.3. These clearance grooves 32 and 33 are provided for the teeth 2a and 2b of both gears.
It is formed outside the contact area A of.

Since the driving gear 2 and the driven gear 3 of this gear pump l rotate only in a fixed direction, the teeth 2a, . . . , 3 of both gears
a... contact each other only on one side.

A cushioning material 35 made of compressible elastic material is provided on the non-contact surface of each tooth. ... is pasted.

Therefore, even if the oil in the gap 36 is compressed or expanded due to the confining action of the teeth of both gears 2.3, this is absorbed by the buffer material 35, and pressure fluctuations are suppressed to a small level.

As the pressure fluctuation absorbing material, for example, leather, oil-resistant neoprene rubber, sea surface synthetic 4# material, etc. are suitable. In particular, leather is easy to apply and has excellent durability.

[Effects of the Invention] As is clear from the above description, in the gear pump according to the present invention, the compression and expansion of oil due to the confinement phenomenon is absorbed by the buffer material, and the oil is inserted into the gap between the driving gear and the driven gear. This reduces the pressure fluctuations in the oil, making it possible to reduce vibration and noise.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an external gear pump which is an embodiment of the present invention, Fig. 2 is a cross-sectional view thereof, Fig. 3 is an enlarged view of its main parts, and Fig. 4 is a conventional external gear pump. This is a diagram showing the main parts of the . l... Gear pump, 2... Driving gear, 3... Driven gear, 5... Case, 6... Gear chamber, 30... Discharge port, 31... Suction port, 35... ...Buffer material. Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] A gear pump having a pair of gears meshing with each other, characterized in that a cushioning material made of a compressible elastic body is affixed to the non-contact surface side of the teeth of at least one of the pair of gears. .