JPH0442544Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a gear pump or motor in which a high pressure area, a low pressure area and an intermediate area are formed outside a sealing member such as a bushing in order to maintain loading balance. .

(Prior Art) The conventional gear pump shown in FIGS. 4 to 8 has gears 2 and 3 built into a case body 1, and bushes that hold gear shafts 4 to 7 on both sides of the gears 2 and 3. Seal members 8 to 11 are arranged, and furthermore, covers 12,
It is closed at 13.

Note that the seal members 8 and 9 and 10 and 11 each form a set, and since the configuration of each set is substantially the same, the seal members 8 and 9 will be described below.

A recessed surface 1a is formed on the outside of the case body 1 around the holes into which the seal members 8 and 9 are fitted, and a first seal 14 is fitted around this recessed surface 1a.

Then, the seal members 8 and 9
When inserted into the case body 1 as shown in the figure,
The outer surfaces of the seal members 8 and 9 are made to be at the same level as the recessed surface 1a. In addition, gear 2,
Protrusions 8a and 9a are provided at positions corresponding to the portions where the inside of the tooth grooves of No. 3 are maintained at a low pressure, and winding bushes 15 and 9a are provided in the shaft holes of the seal members 8 and 9, respectively.
The outside of 16 is made to protrude to the same level as the protrusions 8a and 9a.

A second seal fitted into the inner envelope of the first seal 14
The seal 17 maintains a shape that integrally surrounds the protruding portions of the winding bushes 15, 16 and the protrusions 8a, 9a, and has surrounding portions 17a, 17a' that are separated from them. Chips 18 and 19 are fitted into the surrounding portions 17a and 17a'.

Therefore, the surrounding portion 17 of the second seal 17
The area surrounded by the parts excluding a and 17a' is
It constitutes a low pressure area L into which low pressure oil is introduced from the low pressure introduction hole 20. Furthermore, the inside of the surrounding parts 17a and 17a' constitutes an intermediate pressure area M to which intermediate pressure is introduced from intermediate pressure introduction holes 21 and 22. Furthermore, the first and second
The space between the seals 14 and 17 constitutes a high pressure area H into which high pressure is introduced from the high pressure introduction hole 23.

That is, the inner ends of each of the introduction holes 20 to 23 are as follows:
It opens at the contact surface with the gears 2 and 3, and guides the pressure oil in the tooth groove corresponding to these openings to the corresponding area, and each area becomes equal to the pressure in the tooth groove, and acts as a seal member against the side surface of the gear. The loading force is balanced.

In such a conventional gear pump, since the tips 18 and 19 are movable relative to the seal members 8 and 9, the connecting portions of the surrounding portions 17a and 17a' are prevented from breaking. For example, chip 1
8 and 19 are fixed to the sealing members 8 and 9, pressure is concentrated on the connecting portions of the surrounding portions 17a and 17a' corresponding to the corners, as shown in FIG. It will be torn apart. However, if the chips 18 and 19 are moved as described above, even if pressure is concentrated on the corners, the problem of the surrounding portion being torn will not occur.

(Problems to be solved by the present invention) In the conventional gear pump as described above, the 8th
As shown in the figure, if there is even a slight gap t between the chip 18 and the cover 12, the second seal 17 will protrude from the gap t, and the seal will be damaged. However, between the cover 12 and the seal members 8, 9, the case body 1, the seal members 8,
9 and gears 2 and 3 accumulate, it is practically impossible to keep the gap t small.

Therefore, in conventional gear pumps, accidents frequently occur in which the second seal 17 protrudes from the gap t and is damaged.

The purpose of this invention is to deform the chip using hydraulic pressure to fill the gap and prevent damage to the seal.

(Means for Solving the Problems) In order to achieve the above object, in this invention, the core of the chip is made of metal, and the periphery of this core is covered with synthetic resin.

(Operation of the present invention) When high pressure is applied to the synthetic resin covering the outer periphery of the chip as described above, the synthetic resin is deformed by the pressure action. This deformation of the synthetic resin fills the gap between the chip and the cover.

(Effects of the present invention) Since this invention is configured as described above, the synthetic resin provided around the chip deforms under pressure and closes the gap between the chip and the cover, so the gap is sealed. It will no longer get stuck.

Furthermore, since there is no problem even if there are some gaps, there is no need to strictly determine their dimensions, which makes dimension management easier.

Furthermore, since the area other than the periphery of the chip is made of metal, the overall shape of the chip will not be deformed and will not break.

(Embodiment of the present invention) The second seal S of this embodiment shown in Figs. 1 to 3
As shown in Fig. 3, the volume buttons 15 and 16
It consists of circular parts 24, 25 that come into contact with the protruding part, and surrounding parts 26, 27 formed at the ends of the circular parts, and the circular parts 24, 25 have a double structure to form a high pressure passage 28. ing.

In addition, the symbols 29 and 30 in the figure refer to the circular portion 2.
The fins are formed on the outside of the case body 1, and the fins fit perfectly with the body bore of the case body 1, so that the second seal S can be temporarily fixed.

When attaching the second seal S as described above, a back-up b shown in FIG. 1 is placed around the second seal S.
The material is made of nylon.

Chips 31 and 32 that fit into the surrounding portions 26 and 27 are integrally formed at both ends of the backup b.

That is, the chips 31 and 32 have their core parts 33 and 34 made of iron-based sintered material, and their surroundings made of nylon material 35 and 36 integrated with the back-up b.
covered with That is, when injection molding nylon as the backup b, the core portions 33, 3
4 is also molded together, and the two are integrally molded.

Note that the configuration other than the above is the same as that of the prior art, so the explanation thereof will be omitted.

Thus, when the backup b is aligned with the second seal S, the chips 31 and 32 are inevitably fitted into the surrounding portions 26 and 27.

When high pressure is applied to the chips 31, 32 fitted in the surrounding parts 26, 27 in this way, only the nylon materials 35, 36 are deformed, closing the gap t between them and the cover. Since the gap is closed by the nylon materials 35 and 36 in this way, the second seal S will not be wedged into the gap.

In the above embodiment, the core parts 33, 34 of the chips 31, 32 and the nylon materials 35, 36 are integrally molded, but they may be made into separate members. Further, although the nylon materials 35 and 36 of the chips 31 and 32 are integrated with the backup b, it is of course possible to form the chips completely separately from the backup b.

In any case, as mentioned above, nylon material 35,
36 deforms and closes the gap t, resulting in a structure that can sufficiently withstand operation under severe conditions such as high pressure and high temperature.

[Brief explanation of the drawing]

Drawings 1 to 3 show an embodiment of this invention, in which Fig. 1 is a front view of the backup, Fig. 2 is a sectional view taken along the line - - of Fig. 1, and Fig. 3 is a front view of the second seal. Figures 4 to 9 show a conventional gear pump, where Figure 4 is a sectional view, Figure 5 is a sectional view taken along the line V-V in Figure 4, Figure 6 is a perspective view of the seal member, and Figure 7. 8 is a perspective view of the second seal, FIG. 8 is a sectional view taken along the line -- in FIG. 5, and FIG. 9 is a partial side view showing deformation of the second seal when a chip is fixed. 2, 3...Gear, 8-11...Seal member, 1
4...First seal, H...High pressure area, L...Low pressure area, M...Intermediate pressure area, S...Second seal, 31, 32... Chip, 33, 34... Chip core, 35, 36...Nylon material that covers the periphery of the chip.

Claims (1)

[Scope of utility model registration request] On the outside of the sealing member such as a bushing provided on the side of the gear, that is, on the opposite side from the side that contacts the gear,
A first seal is provided, and a second seal is provided inside the first seal, a high pressure area and a low pressure area are partitioned by these seals, and an encircling portion is integrally formed with the second seal. The area surrounded by this surrounding part is defined as an intermediate pressure area, and a chip other than the sealing member is fitted into this surrounding part, and the pressure in the tooth groove corresponding to that area is introduced into each of these areas. A gear pump or motor in which the core of the chip is made of metal and the periphery of the core is covered with synthetic resin.