JPH11230055A - Internal gear-type trocoid gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal gear-type trocoicl gear pump excellent in corrosion resistance and abrasion resistance and having the long live even if it is used as a coolant supplying pump. SOLUTION: An internal gear-type trocoid gear pump including a rotatable outer rotor having the internal tooth and an inner rotor rotatably provided in the outer rotor 13 and having the external tooth to be meshed with the internal tooth, bearing members of a rotor shaft 23 for supporting the inner rotor are taken as ceramic-made sleeve bearing members 19, 21, and ceramics is flame-sprayed to the shaft outer peripheral surfaces of parts 23A, 23B of the rotor shaft 23 to be fitted to the sleeve bearing members 19, 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inscribed trochoid gear pump, and more particularly to an inscribed trochoid gear pump used under highly corrosive conditions, such as a coolant supply pump for a machine tool. is there.

[0002]

2. Description of the Related Art A coolant supply pump for a machine tool includes a rotatable outer rotor having internal teeth and an inner rotor rotatably provided in the outer rotor and having external teeth meshing with the internal teeth. Contact trochoidal gear pumps have been used in the past.

[0003] In a conventional inscribed trochoidal gear pump,
The bearing of the rotor shaft that supports the inner rotor has a rolling bearing structure with a ball bearing member.
No special anti-corrosion or anti-abrasion treatment is applied to the outer rotor.

[0004]

In the conventional inscribed trochoidal gear pump, the bearing of the rotor shaft supporting the inner rotor has a rolling bearing structure by a ball bearing member. In some cases, corrosion due to rust or the like may occur in the bearing portion, and the bearing portion may be stuck due to the corrosion at the time of stopping, and the operation may not be performed again. Also,
Corrosion promotes wear of the bearing portion, and the incomplete separation of chips causes the chips to penetrate into the ball rolling surface of the ball bearing member, thereby significantly shortening the life of the ball bearing member due to galling.

In the conventional internal trochoid gear pump, since the inner rotor and the outer rotor are not subjected to a special anti-corrosion treatment or an anti-abrasion treatment, corrosion and
They are prone to wear and their durability is low, and they are usually treated as non-durable parts and require periodic replacement of parts.

As described above, the conventional inscribed trochoidal gear pump is small in size and high in pump efficiency, but it is said that the pump life is short especially when used as a coolant supply pump.

The present invention has been made in view of the above-mentioned problems, and has excellent corrosion resistance and wear resistance, and has a long life even when used as a coolant supply pump. It is an object of the present invention to provide an inscribed trochoidal gear pump.

[0008]

In order to achieve the above object, an inscribed trochoidal gear pump according to the present invention has a rotatable outer rotor having internal teeth and a rotatable inner rotor. An inner trochoid gear pump including a rotatable inner rotor having external teeth meshing with the internal teeth, wherein a bearing member of a rotor shaft supporting the inner rotor is formed of a ceramic sleeve bearing member, The outer peripheral surface of the shaft at a portion where the shaft is fitted to the sleeve bearing member is ceramic-sprayed.

According to the inscribed trochoid gear pump according to the present invention, since the bearing member of the rotor shaft is constituted by the sleeve bearing member made of ceramics, corrosion, wear and galling due to rust or the like do not occur. In addition, since the ceramic shaft is sprayed on the outer peripheral surface of the shaft where the rotor shaft fits into the sleeve bearing member, corrosion and wear due to rust etc. do not occur in this portion, and the soundness of the bearing portion of the rotor shaft is secured. Is done.

In order to achieve the above object, an inscribed trochoidal gear pump according to the second aspect of the present invention includes a rotatable outer rotor having internal teeth, and a rotatable inner rotor provided in the outer rotor. In the inscribed trochoidal gear pump including the inner teeth and an inner rotor having outer teeth meshed with the inner teeth, the outer rotor and the inner rotor are subjected to gas nitriding.

According to the internal trochoid gear pump of the present invention, since the outer rotor and the inner rotor are subjected to the gas nitriding treatment, the corrosion resistance and wear resistance are improved, and the life of these parts is extended.

In order to achieve the above object, an inscribed trochoidal gear pump according to the third aspect of the present invention is provided with a rotatable outer rotor having internal teeth and a rotatable inside of the outer rotor. In the inscribed trochoidal gear pump including the inner teeth and an inner rotor having external teeth meshed with the inner teeth, a bearing member of a rotor shaft supporting the inner rotor is formed of a ceramic sleeve bearing member, and the rotor shaft is formed of the sleeve bearing. The outer peripheral surface of the shaft fitted to the member is sprayed with ceramics, and the outer rotor and the inner rotor are gas-nitrided.

According to the inscribed trochoid gear pump of the present invention, since the bearing member of the rotor shaft is formed of a sleeve bearing member made of ceramics, it is free from corrosion, wear and galling due to rust and the like. In addition, since the ceramic shaft is sprayed on the outer peripheral surface of the shaft where the rotor shaft fits into the sleeve bearing member, corrosion and wear due to rust etc. do not occur in this portion, and the soundness of the bearing portion of the rotor shaft is secured. In addition, since the outer rotor and the inner rotor are gas-nitrided, corrosion resistance and wear resistance are improved, and the life of these components is extended.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

1 and 2 show an embodiment of an inscribed trochoidal gear pump according to the present invention. The inscribed trochoid gear pump forms a pump housing assembly 11 by a body 1, a pump body 3 disposed on both sides thereof and fastened by bolts 7 and knock pins 9, and a bearing housing 5.

In the body 1, both sides of the pump body 3 are provided.
The outer rotor 13 is rotatably provided in a state sandwiched between the bearing housing 5 and the outer rotor 13.

Bearing bushes (sleeve support members) 15, 17 are fixed to the pump body 3 and the bearing housing 5, respectively. Ceramic sleeve bearing members 19, 21 are press-fitted to the bearing bushes 15, 17, respectively. Have been.

The sleeve bearing members 19 and 21 are on the same axis, and rotatably support both ends of a rotor shaft 23 extending through the inside of the outer rotor 13.

The ceramics constituting the sleeve bearing members 19 and 21 are high strength ceramics such as alumina, zirconia silicon carbide and zirconia silicon nitride, and are formed into a sleeve shape by sintering.

The rotor shaft 23 is made of stainless steel or the like, and has a portion 2 fitted to the sleeve bearing members 19 and 21.
Ceramics such as alumina and silicon carbide are sprayed on the outer peripheral surfaces of the shafts 3a and 23b. The thickness of the ceramic sprayed coating may be about 0.2 to 0.3 mm.

As a result, the bearing of the rotor shaft 23 becomes a sliding bearing formed by the ceramics forming the sleeve bearing members 19 and 21 and the ceramics sprayed on the portions 23a and 23b of the rotor shaft 23.

An inner rotor 27 is attached to the rotor shaft 23 by a key 25. The outer rotor 13 in the body 1 has internal teeth 29, and the inner rotor 27, which is rotationally driven in the outer rotor 13 by the rotor shaft 21, has external teeth 31 according to a trochoidal curve. It meshes with the internal teeth 31 to define a pump chamber 33.

The outer rotor 13 is made of, for example, cast iron in which fine eutectic graphite and granular ferrite are distributed in a fine pearlite base material, and diffuses and permeates active nitrogen gas from the entire surface with a nitriding gas such as ammonia gas. The entire surface including the inner teeth 29 is subjected to a gas nitriding treatment at a depth of several μ to several tens μ. Since the outer rotor 13 is a cast product, the processing cost can be reduced.

The inner rotor 27 includes, for example, a portion of the inner teeth 31 by diffusing and penetrating active nitrogen gas from the entire surface of a heat-treated tempered steel (SACM equivalent material) with a nitriding gas such as ammonia gas. The entire surface is subjected to gas nitriding with a depth of several μ to several tens μ. Note that the outer rotor 13 can also be formed of a heat-treated tempered steel as a base material, similarly to the inner rotor 27.

This gas nitriding treatment is preferably performed by a gas nitriding treatment method in which a white layer (epsilon layer) is little deposited so that a post-processing polishing operation can be omitted.

As described above, the bearing member of the rotor shaft 23 is constituted by the sleeve bearing members 19 and 21 made of ceramics, and the shaft outer peripheral surfaces of the portions 23a and 23b where the rotor shaft 23 is fitted to the sleeve bearing members 19 and 21. Since the ceramics are sprayed onto the bearing, the sliding surfaces of these bearings are free from corrosion, wear and galling due to rust, etc.
The soundness of the bearing portion of the rotor shaft 23 is stably ensured over a long period of time without causing premature wear.

Since the inner teeth 29 of the outer rotor 13 and the outer teeth 31 of the inner rotor 27 are both gas-nitrided, the meshing portion between the inner teeth 29 of the outer rotor 13 and the outer teeth 31 of the inner rotor 27 is formed. Corrosion resistance and wear resistance are improved, the life of these parts is extended, the outer rotor 13 and the inner rotor 27 can be handled as super-life parts, and even when used as a coolant supply pump, the inscribed trochoid as a whole can be used. The life of the gear pump is extended.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to this, and various embodiments may be made within the scope of the present invention. The possibilities will be clear to the skilled person.

[0029]

As will be understood from the above description, according to the inscribed trochoid gear pump according to the first aspect of the present invention, the bearing member of the rotor shaft is formed of a sleeve bearing member made of ceramics. This does not cause corrosion, abrasion or galling due to rust, etc., and since the rotor shaft is sprayed with ceramics on the outer peripheral surface of the shaft where it fits into the sleeve bearing member, corrosion,
The soundness of the bearing portion of the rotor shaft is stably ensured for a long period of time without causing abrasion and without causing sticking and early abrasion.

According to the inscribed trochoid gear pump according to the second aspect of the present invention, since the outer rotor and the inner rotor are subjected to the gas nitriding treatment, the corrosion resistance and wear resistance are improved, and the life of these parts is extended. The life of the internal trochoid gear pump can be extended even when used as a coolant supply pump.

According to the inscribed trochoid gear pump according to the third aspect of the present invention, since the bearing member of the rotor shaft is formed of a sleeve bearing member made of ceramics,
This does not cause corrosion, wear or galling due to rust, etc. In addition, since the rotor shaft is sprayed with ceramics on the outer peripheral surface of the shaft fitting part, corrosion and wear due to rust etc. occur on this part. Since the bearings of the rotor shaft are stable and stable for a long period of time without sticking and premature wear, and the outer and inner rotors are gas-nitrided, corrosion resistance does not occur. In addition, the life of these parts is improved, and the life of the inscribed trochoidal gear pump is extended as a whole even when used as a coolant supply pump.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing an outer rotor / inner rotor portion of one embodiment of the inscribed trochoidal gear pump according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 3 Pump main body 5 Bearing housing 7 Bolt 9 Dowel pin 11 Pump housing assembly 13 Outer rotor 15, 17 Bearing bush 19, 21 Sleeve bearing member 23 Rotor shaft 25 Key 27 Inner rotor 29 Internal teeth 31 External teeth 33 Pump chamber

Continued on the front page (72) Inventor Takehisa Iwata 2068-3 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Maitec Numazu (72) Inventor Haruhiko Kikuchi 2068-3, Ooka, Numazu City, Shizuoka Prefecture Numazu Office ( 72) Inventor Kazuo Tsuboi 1-17-7 Kita, Okegawa-shi, Saitama (72) Inventor Koichiro Ito 2-6-11C-428, Miyazaki, Miyama-ku, Kawasaki, Kanagawa 428 (72) Inventor Koji Nakazawa Mimadori, Nanyo-shi, Yamagata 337-14

Claims (3)

[Claims] 1. An inscribed trochoidal gear pump comprising: a rotatable outer rotor having internal teeth; and an inner rotor rotatably provided in the outer rotor and having external teeth meshing with the internal teeth. An inscribed trochoid, wherein the bearing member of the rotor shaft to be supported is formed of a ceramic sleeve bearing member, and the rotor shaft is sprayed with ceramic on the outer peripheral surface of the shaft at a portion fitted to the sleeve bearing member. Gear pump. 2. An inscribed trochoid gear pump comprising: a rotatable outer rotor having internal teeth; and an inner rotor rotatably provided in the outer rotor and having external teeth meshing with the internal teeth. The inner trochoidal gear pump, wherein the inner rotor is subjected to a gas nitriding treatment. 3. An inscribed trochoid gear pump comprising: a rotatable outer rotor having internal teeth; and an inner rotor rotatably provided in the outer rotor and having external teeth meshing with the internal teeth. The bearing member of the rotor shaft to be supported is composed of a sleeve bearing member made of ceramics. An inscribed trochoidal gear pump characterized in that: