JP2579772Y2 - Gear pump for highly corrosive fluids - Google Patents

Description

[Detailed description of the invention]

[0001]

Industrial Applicability The present invention is suitable for transferring a highly corrosive fluid such as a stock solution for acrylic fiber (hereinafter referred to as "acryl stock solution") used for spinning in a fixed amount. The present invention relates to a gear pump for sexual fluid.

[0002]

FIG. 4 is a cross-sectional view of a typical prior art. For example, a gear pump 1 having corrosion resistance is used to transfer a constant amount of an acrylic stock solution used for spinning. The gear pump 1 has a casing 6 having a pump chamber 5 in which a driving gear 3 and a driven gear 4 are housed.
Are sandwiched between two side plates 7 and 8 from both sides thereof, and inner surfaces 9 and 10 of the side plates 7 and 8 facing each other are gears 3 and
4 from both sides 11, 13;
They are separated by a slight gap of about m. Bearings 17 and 18 such as metal bearings that support a drive shaft 16 that is rotationally driven by a rotational force from a motor (not shown) are press-fitted into the side plates 7 and 8 respectively.
The drive shaft 16 is supported by the shafts 7 and 18 without restricting the displacement in the axial direction. Such a drive shaft 16
Is press-fitted into the drive gear 3 in the pump chamber 5, and a rotational force is transmitted to the drive gear 3 as the drive shaft 16 rotates.
A driven shaft 19 is inserted through the driven gear 4 driven by the driving gear 3 so as to rotatably support the driven gear 4 around its axis. 8 and the side plate 7
Is press-fitted into the shaft hole 20 and fixed.

The driving gear 3, the driven gear 4, and the driving shaft 1
6. The bearings 17, 18 and the driven shaft 19 are made of a cobalt-based alloy, and the side plates 7, 8 are made of austenitic stainless steel plated with hard chrome. By using such a material, corrosion resistance, wear resistance, and seizure resistance are improved. Each of the gears 3 and 4 is an involute gear for obtaining a quantitative property. However, as described above, since the highly corrosive fluid is transferred, the wear is fast and the quantitative property is reduced in a short period of time. In particular, due to the generation of high stress due to the meshing of the teeth between the gears 3 and 4, the wear on each tooth surface is remarkable, and it is necessary to replace it with a new gear in about half a year, which is a problem of low economic efficiency.

As another prior art, for example, Japanese Patent Application Laid-Open No. 4-191484 (Japanese Patent Application No. 2-317875) discloses that
Although it is disclosed that at least one of the gear, the gear shaft, the side plate, and the casing is made of a ceramic having a surface of 0.05 μm or less, there is a problem that there are many partial defects and wear.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a gear pump for highly corrosive fluid which can improve the wear resistance without causing seizure.

[0006]

SUMMARY OF THE INVENTION The present invention provides a casing in which a pump chamber is formed, two side plates sandwiching the casing, made of a corrosion-resistant material, and a nickel-based alloy. The drive gear to be housed, a driven gear made of a nickel-based alloy, meshing with the drive gear in the pump chamber, and a cobalt-based alloy, each end face of each of the two axial end portions in a state of being pressed into the drive gear, A drive-side bushing protruding from both side surfaces of the drive gear, and a driven-side bushing made of a cobalt-based alloy, and each end face of both ends in the axial direction protruding from each side surface of the driven gear while being pressed into the driven gear, A drive shaft made of a cobalt-based alloy, which is press-fitted into the drive-side bushing and is driven to rotate around the rotation axis, and a cobalt-based alloy which is press-fitted into each side plate, and A highly corrosive fluid comprising: a pair of bearings that support a drive shaft; and a driven shaft that is made of a cobalt-based alloy and press-fits into the side plate to support a driven gear and a driven side bushing in a pump chamber. Gear pump.

[0007]

According to the present invention, a drive gear and a driven gear meshing with the drive gear are housed in a pump chamber formed in the casing, and a bushing is press-fitted into each of these gears. A drive shaft is press-fitted into the drive-side bushing press-fitted into the drive gear, and the drive shaft is supported by bearings press-fitted into two side plates sandwiching the casing. A driven shaft press-fitted into the side plate is inserted into the driven-side bushing press-fitted into the driven gear to support the driven gear and the driven-side bushing, and the drive shaft is driven to rotate about a rotation axis. As a result, the rotational force is transmitted to the drive gear, and the driven gear is driven, and the highly corrosive fluid such as, for example, an acrylic stock solution supplied to the meshing portion of each gear is stored in the tooth space, and the rotation of each gear is performed. And the fluid in the tooth space is pushed out by the meshing of the teeth in the meshing portion, and thus the highly corrosive fluid is transferred in a fixed amount.

The drive gear and the driven gear are made of a nickel-based alloy, and the bushing pressed into these gears is made of a cobalt-based alloy. The drive-side bushing press-fitted into the drive gear has hard chrome-plated ends at both ends in the axial direction protruding from both side surfaces of the drive-side gear.These end faces are not restricted by the drive shaft being displaced in the axial direction. Contact each side plate. In this way, a cobalt-based alloy and a high-hardness material of hard chromium plating are used for parts that come into contact with each other, and a nickel-based alloy having high corrosion resistance is used for parts that do not come into contact with each other. Therefore, only the both end surfaces of the drive side bushing protruding from both side surfaces of the drive gear slide on the respective side plates, preventing the drive gear from contacting the respective side plates and causing seizure. Is excessively large, and the fluid in the tooth space leaks, thereby preventing the quantitative property from being lowered.

The driven gear is made of a nickel-based alloy,
A bushing made of a cobalt-based alloy is press-fitted into the driven gear, and a driven shaft made of a cobalt-based alloy is inserted into the bushing, and the driven shaft is press-fitted into a side plate. Therefore, the driven gear is rotatably supported around the driven shaft following the rotation of the driving gear. The bushings press-fitted into such driven gears are also formed so that their respective end faces in the axial direction protrude from both side faces of the driven gear, and come into contact with the hard chrome plated side plates. Therefore, only the both end surfaces of the driven gear side bushing slide on each side plate, and the driven gear is prevented from coming into contact with each side plate and seizure is prevented from occurring. Since each gear is made of a material having high corrosion resistance in this way, and a high hardness material is used for the sliding portion,
Both corrosion resistance and seizure resistance can be improved.

[0010]

FIG. 1 shows a gear pump 25 according to an embodiment of the present invention.
FIG. For example, a gear pump 25 used to transfer a highly corrosive fluid such as a stock solution for acrylic fiber (hereinafter abbreviated as an acrylic stock solution) in a fixed amount includes a casing 27 in which a pump chamber 26 is formed and a corrosion-resistant material. For example, two side plates 28 and 29 sandwiching the casing 27 and made of a nickel-based alloy and made of a hard-chromium-plated austenitic stainless steel, a driving gear 30 housed in the pump chamber 26, The drive gear 3 is made of an alloy.
0, and a drive-side bushing 3 made of a cobalt-based alloy and pressed into the drive gear 30.
3, a driven side bushing 34 made of a cobalt-based alloy and pressed into the driven gear 31; and a drive shaft 35 made of a cobalt-based alloy and pressed into the drive-side bushing 33 and driven to rotate around a rotation axis. And a pair of bearings 36, 37 press-fit into the respective side plates 28, 29 to support the drive shaft 35, and a pair of bearings made of a cobalt-based alloy. The driven shaft 3 press-fitted into the pump chamber 28 and supporting the driven gear 31 and the driven side bushing 34 in the pump chamber 26.
8 is included.

FIG. 2 is an enlarged sectional view of the vicinity of the drive-side bushing 33, and FIG. 3 is a sectional view taken along the line III-III in FIG. The drive-side bushing 33 is press-fitted into the drive gear 30 as described above, and the end faces 41, 43 at both ends in the axial direction project from the both side faces 39, 40 of the drive gear 30 by the protrusion lengths L1, L2. I have. These protrusion lengths L1 and L2 are selected to be several μm. If the protrusion length is small, when the drive gear 30 is displaced in the axial direction,
Each side plate 28, 29 facing each other across the pump chamber 26
The drive gear 30 comes into contact with the inner surfaces 44 and 45 of the drive shaft, causing seizure. If the protruding lengths L1 and L2 are large, the inner surfaces 44 and 45 of the side plates 28 and 29 and the side surfaces 3
The gaps L3 and L4 between the gaps 9 and 40 are too large, and the fluid stored in the tooth space leaks to both sides, and the quantitative property is reduced. Therefore, the protrusion lengths L1 and L2 are several μm.
Is chosen.

The other driven side bushing 34 also
As in the case of the drive-side bushing 33 described above, the driven gear 31 projects from both side surfaces by a similar amount.

The drive side bushing 33 has a keyway 49.
The drive shaft 35 is provided with a key 50 that fits into the key groove 49. The drive gear 35 rotates the drive shaft 35 with the drive gear 30 displaceable in the axial direction with respect to the drive shaft. 30.

The inventor of the present invention has conducted experiments using various materials and found that nickel-based alloys are excellent in corrosion resistance. However, when such nickel-based alloys are used for gears, Seizure easily occurs on the driven shaft 38 and the side plates 28 and 29 made of the cobalt-based alloy. As a countermeasure, bushings 33 and 34 made of the cobalt-based alloy are pressed into the gears 30 and 31. As a result, the driving gear 30
And by making the driven gear 31 made of a nickel-based alloy, wear of each tooth surface is reduced, and durability is reduced from 0.5 years to 2 years.
It has been confirmed that the year will improve.

Further, by forming the drive-side and driven-side bushings 33, 34 with a cobalt-based alloy and press-fitting these bushings 33, 34 into the respective gears 30, 31, seizure with the driven shaft 38 is prevented, and The end faces 41, 43 of these bushings 33, 34 are connected to the respective gears 30,
By projecting from the side surfaces 39, 40; 46, 47 of the side 31, the direct contact between the inner surfaces 44, 45 of the side plates 28, 29 and the respective gears 30, 31 is eliminated, and the side plates 28, 2
It was confirmed that seizure with No. 9 could be prevented.

With such a configuration, it is possible to improve the corrosion resistance, the wear resistance and the seizure resistance, and to prevent a decrease in the quantitativeness.

[0017]

As described above, according to the present invention, the drive gear and the driven gear are formed from a corrosion-resistant nickel-based alloy, and a bushing made of a high-hardness cobalt-based alloy is pressed into each gear. The drive shaft, which protrudes in the axial direction and is not restricted in axial displacement, is formed of a cobalt-based alloy of the same material as the bushing to prevent seizure and wear of the sliding portion and improve corrosion resistance. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a gear pump 25 according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the vicinity of a drive side bushing 33.

FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a sectional view showing a typical prior art gear pump 1;

[Explanation of symbols]

 Reference Signs List 25 gear pump 26 pump chamber 27 casing 28, 29 side plate 30 drive gear 31 driven gear 33 drive side bushing 34 driven side bushing 35 drive shaft 36, 37 bearing 38 driven shaft 39, 40; 46, 47 side surface 41, 43 end face 44, 45 inside

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F04C 13/00 F04C 2/18 311 F04C 15/00

Claims (1)

(57) [Scope of request for utility model registration] A casing formed with a pump chamber, two side plates sandwiching the casing made of a corrosion-resistant material, a drive gear made of a nickel-based alloy, and housed in the pump chamber; A driven gear that is made of a base alloy and meshes with the drive gear in the pump chamber; and a cobalt-based alloy that is pressed into the drive gear, and each end face at both axial ends protrudes from both side faces of the drive gear. A drive-side bushing, made of a cobalt-based alloy, and a driven-side bushing, in which each end face at both ends in the axial direction protrudes from each side face of the driven gear when pressed into the driven gear, and made of the cobalt-based alloy, A drive shaft press-fit into the side bushing and driven to rotate around the rotation axis; and a one made of a cobalt-based alloy, which is press-fitted into each side plate to support the drive shaft. And the bearing of, consist cobalt-based alloy, highly corrosive fluid gear pump which comprises a driven shaft for supporting the driven gear and a driven-side bushing in the pump chamber is pressed to the side plate.