JPS61179829A - Gear driving type oil pump - Google Patents

Abstract

PURPOSE:To prevent the abnormal wear and pitting of a driven gear attached to a pump shaft of a gear drive type oil pump by forming said gear of a material having the specific chamical compsn. consisting of Zn, Al, Ni, Ti and Cu. CONSTITUTION:The driven gear 16 of the gear drive type oil pump 10 which drives rotationally a pair of gears contained in a pump body 11 by means of a drive gear 19 provided to the pump drive shaft 18 via the driven gear 16 attached to one end of the pump shaft coupled to said gears is formed of the material having the chemical compsn. consisting of 14-17wt% Zn, 6.5-7.5% Al, 1.5-2.5% Ni, 1.5-2.5% Ti and the balance Cu. The abnormal wear and pitting of the gear 16 are thereby simultaneously prevented and the reliability of the pump operation is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (INDUSTRIAL APPLICATION) The present invention relates to a gear-driven oil pump, and more particularly to a gear-driven oil pump forming a driven gear coupled to an external extension of a pump shaft. It's about materials. The pump of the present invention is used as a lubricating oil pump for an internal combustion engine.

(Prior art) Conventionally, as an example of this type of oil pump,
The one described in Japanese Patent No.-39590 is known.

That is, in this oil pump, a pair of pump gears that mesh with each other are disposed within the pump body, and a pump shaft is coupled to the pump gears. One end of the pump shaft extends outside the pump body, and a driven gear is coupled to the externally extending portion by a key or the like. In this type of oil pump driving method, a drive gear is formed on a pump drive shaft that is driven by an engine via a timing belt, and the driven gear is arranged to mesh with the drive gear. Therefore, the rotation of the pump drive shaft is transmitted to the driven gear, and the pump action is performed by rotating the pump gear via the pump shaft.

(Problem to be Solved by the Invention) Now, the engagement between the drive gear of the pump drive shaft and the driven gear coupled to the externally extending portion of the pump shaft is constituted by a worm gear means whose rotational direction changes by 90 degrees. . Therefore, the area of the engaging surfaces of both gears is small, and the surface pressure that the gears receive is extremely high. Moreover, in recent years, as the pump capacity of oil pumps has increased and the rotation speeds have increased, the torque transmitted from the drive gear to the driven gear has increased, so a material with excellent strength is required for the driven gear.

However, when aluminum bronze (an alloy with a copper base and aluminum as the main component) is used as a material for conventional driven gears, for example, pitting occurs less, but wear increases. When using brass (an alloy with a copper base and zinc as the main component), the amount of wear was small, but there was a problem in that pitting occurred. In this way, in conventional driven gears, due to abnormal wear or pitching,
Because the meshing between the drive gear and the driven gear is not normal, the rotational driving force of the pump drive shaft is not transmitted to the oil pump reliably, and as a result, the pump cannot function, causing a practical inconvenience such as engine seizure. Ta.

Therefore, the technical object of the present invention is to prevent the occurrence of abnormal wear and pitching of the driven gear.

[Structure of the invention]

(Means to solve the problem) The technical measures taken to solve the above technical problem are:
The material forming the driven gear has a chemical composition consisting of Zn: 14-17 (wt%) Als 6.5-7.5 Ni: 1.5-2.5 Ti: 1.5-2.5 Cu: the balance , that is. That is, Alt
By reducing the Zn content to 7.5% or less, the amount of wear is reduced, and by reducing the Zn content to 17% or less, occurrence of pitting is prevented.

(Operation) By adopting the above technical means, it is possible to prevent the occurrence of abnormal wear and pitching in the driven gear, and therefore the rotational driving force of the pump drive shaft is reliably transmitted to the oil pump through the driven gear. It becomes possible to transmit the signal to a pair of pump gears.

(Example) An example embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

The gear-driven oil pump 10 shown in FIGS. 1 and 2 includes a pump body 11, and a pair of mutually meshing pump gears 12, 13 are disposed in the lower part of the body 11. The pump gear 12 is rotatably supported by a driven shaft 14 press-fitted into the pump body 1, while the pump gear 13 is connected to the lower end of a pump shaft 15 rotatably inserted into the pump body 11 by a key or the like. The upper end of the pump shaft 15 is the pump body 11
A driven gear 16 is coupled to the externally extending portion 15a by a key 17. The driven gear 16 is meshed with the drive gear 19 of the pump drive shaft 18, and the driven gear 16 is engaged with the drive gear 19 of the pump drive shaft 18.
The rotational driving force from 8 is transmitted to the driven gear 16, and is transmitted to the pair of pump gears 12 and 13 via the pump shaft 15.
rotates and performs a pumping action. Note that the cover 20 is bolted to the lower end of the pump body 11 to form a pump chamber (not shown).

Now, as described above, the driven gear 16 that transmits the driving force of the pump drive shaft 18 to the pump shaft 15 has Zn: 14 to 17 (% by weight) AJ? It is formed from a material having a chemical composition of 6.5 to 7.5 Ni: 1.5 to 2.5 Ti: 1.5 to 2.5 Cu: the balance.

By employing this material for forming the driven gear 16, it has become possible to prevent abnormal wear and pitching of the driven gear 16.

That is, Fig. 3 shows the test results of the change in the amount of driven gear wear between the materials of the present invention and the conventional material, and Fig. 4 also shows the test results of the amount of wear over time.
The figure also shows the test results for the pitching occurrence rate. As is clear from FIGS. 3, 4, and 5, in the driven gear according to the present invention, abnormal wear and pitching can be reduced at the same time.

〔Effect of the invention〕

In the oil pump according to the present invention, abnormal wear and pitching of the driven gear can be prevented at the same time, so the rotational driving force of the pump drive shaft can be reliably transmitted to the pump shaft, and therefore the pump operation can be improved. It is possible to improve reliability and prevent a reduction in engine seizure.

[Brief explanation of drawings]

The first head is a sectional view showing an embodiment of the oil pump according to the present invention, the second figure is an external view of the oil pump shown in FIG.
FIG. 4 is an explanatory diagram showing the test results of the wear amount, FIG. 4 is an explanatory diagram showing the test results of the change in the wear amount, and FIG. 5 is an explanatory diagram showing the test results of the pitching occurrence rate. 10...Gear-driven oil pump, 11...Pump body, 12/13...Pump gear. 15... pump shaft, 15a... external extension part,
16... Driven gear, 19... Pump drive shaft

Claims (1)

[Scope of Claims] A pump body, a pair of pump gears disposed within the pump body and meshing with each other, a pump shaft coupled to the pump gear and having one end extending outside the pump body, and a pump shaft of the pump shaft. a driven gear coupled to the external extension and driven by the pump drive shaft, the driven gear comprising: Zn: 14-17 (wt%) Al: 6.5-7.5 Ni: 1.5-2. 5 Ti: 1.5 to 2.5 Cu: The balance is a gear-driven oil pump formed from a material having a chemical composition of 1.5 to 2.5.