JP2002161871A - Oil pump and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil pump and a manufacturing method therefor capable of restraining occurrence and advance of erosion by further improving wear resistance at a sliding section of the oil pump, and of preventing an increase in manufacturing cost. SOLUTION: This oil pump 11 comprises an oil pump body 12, an oil pump cover 13, a shaft 14, a driving gear 15, and a driven gear 16. The sliding section 12b is formed out of ceramic particle-dispersed aluminum base composite material. The oil pump body 12 is obtained by casting the sliding part 12b with an aluminum alloy. The oil pump 11 is manufactured by setting the driving gear 15 and the driven gear 16 inside the oil pump body 12 and the oil pump cover 13, and attaching and fixing the oil pump cover 13 to the oil pump body 12 with bolts 17 with the shaft 14 inserted in the oil pump body 12 and the oil pump cover 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump and a method of manufacturing the same, and more particularly, to an oil pump incorporated in an automatic transmission used for a vehicle such as an automobile and a method of manufacturing the same. It is about.

[0002]

2. Description of the Related Art In recent years, replacement of iron-based materials (mainly cast iron) with aluminum-based materials has been progressing rapidly in order to reduce the weight of vehicles mainly in the automobile industry. Therefore, as a material of an oil pump body and an oil pump cover forming an oil pump which is one of the vehicle parts,
An aluminum alloy may be used, but it is inferior in performance, such as strength, as compared to iron-based materials. Due to the generation of air bubbles in the oil of the oil pump (cavitation), the oil pump Erosion (erosion) was likely to occur in the area where the erosion occurred.

[0003] In particular, in each sliding portion of the oil pump body and the oil pump cover in which gears such as a drive gear and a driven gear, which are components of the oil pump, come into contact with each other, a synergistic effect due to cavitation and the sliding force of the gear. Erosion was easily generated by the action, and erosion was also easily progressed. Here, Si is added in a weight ratio of 14% by weight or more.
By forming the oil pump body and the oil pump cover using a hypereutectic aluminum alloy containing 20% by weight, the strength of the oil pump body and the oil pump cover may be improved. It was not enough to control.

[0004] Conventionally, as an oil pump for suppressing the occurrence and progress of erosion in a sliding portion, for example, an oil pump described in Japanese Utility Model Publication No. 3-15832 has been known. The sliding portion of this conventional oil pump is provided with a layer in which ceramic fibers are dispersed in an aluminum alloy matrix, and this layer is designed to ensure the strength of the sliding portion. That is, by ensuring the strength of the sliding portion of the oil pump, the sliding portion is less likely to be worn, and the occurrence and progress of erosion in the sliding portion are suppressed.

[0005] Further, this oil pump forms a molded article (sliding portion) of a predetermined shape by suction-molding ceramic fibers.
It is manufactured by arranging the molded body in a mold, pouring a molten metal made of an aluminum alloy, and performing pressure casting (high-pressure mold casting) at a high pressure [for example, 800 (kg / square centimeter)]. .

[0006]

However, in the above-described oil pump of the prior art, when the end portion (sharp portion) of the ceramic fiber is exposed at the sliding portion, the oil pump slides in contact with the sliding portion. Not only may the gears be easily damaged, etc., but also, on the contrary, the sliding parts are easily worn due to the sliding force of the gears, and the wear resistance of the sliding parts is extremely reduced. There was a fear. Further, since the molded body made of ceramic fibers is very expensive, the production cost of the oil pump is increased.
In addition, when an oil pump according to the related art is to be manufactured, the manufacturing method is limited to a high-pressure mold casting method, so that a gravity mold casting method, a low-pressure mold casting method, and a sand mold casting method are used. Could not be applied.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a main object thereof is to further improve the wear resistance of a sliding portion of an oil pump to suppress the occurrence and progress of erosion. It is an object of the present invention to provide an oil pump and a method for manufacturing the same, which can be performed while preventing an increase in manufacturing cost. The other purpose is not only high pressure die casting, but also gravity die casting, low pressure die casting,
An object of the present invention is to provide a method of manufacturing an oil pump applicable to a sand casting method.

[0008]

In order to achieve the above object, an invention according to claim 1 is characterized in that an oil pump body made of an aluminum alloy and an oil pump attached to the oil pump body are also made of an aluminum alloy. And an oil pump in which a gear abuts each sliding portion of the oil pump body and the oil pump cover and slides, wherein at least a part of the sliding portion is made of a ceramic particle-dispersed aluminum-based composite material. The gist is that it was formed.

According to the first aspect of the present invention, at least a part of the sliding portion is formed of the ceramic particle-dispersed aluminum-based composite material. Even in the case where the gear is exposed, the possibility that the gear is damaged as in the related art is reduced. To explain in more detail, the end of the ceramic fiber according to the prior art has a sharp portion,
Since a part of the ceramic particles according to the present invention has a curved portion, even if the gear abuts and slides on the sliding portion formed of the ceramic particle-dispersed aluminum matrix composite material, the gear is damaged. And the like, and the abrasion resistance of the sliding portion is unlikely to be extremely reduced as in the prior art.

Therefore, as compared with the prior art, the wear resistance of the sliding portion of the oil pump is further improved, and the occurrence and progress of erosion in the sliding portion are suppressed. Further, since the ceramic particle-dispersed aluminum-based composite material is less expensive than the ceramic fiber material according to the prior art, the production cost of the oil pump does not increase as compared with the prior art.

According to a second aspect of the present invention, in the oil pump according to the first aspect, the sliding portion of the oil pump body has a ceramic particle diameter of 5 μm to 40 μm.
The gist of the invention is that it is formed of a ceramic particle-dispersed aluminum-based composite material of m.

Here, the particle size of the ceramic particles in the ceramic particle-dispersed aluminum-based composite material is set to 5
The reason for setting the range of μm to 40 μm is that when the particle size is less than 5 μm, there is a possibility that the wear resistance of the sliding portion of the oil pump body may not be sufficiently secured, and when the particle size exceeds 40 μm. In addition, when the gear abuts on the sliding part where a part of the ceramic particles is exposed and slides, the gear may not only be easily damaged, but also the abrasion resistance of the sliding part of the oil pump body may occur. This is because the property may be extremely reduced.

According to the second aspect of the invention, in addition to the function of the first aspect, the particle size of the ceramic particles in the ceramic particle-dispersed aluminum-based composite material is set to a predetermined range. Therefore, an extreme decrease in wear resistance of the sliding portion of the oil pump body is reliably prevented.

According to a third aspect of the present invention, there is provided an oil pump body made of an aluminum alloy, and an oil pump cover also made of an aluminum alloy attached to the oil pump body. In the method for manufacturing an oil pump in which a gear abuts on each sliding portion and slides, at least one of the oil pump body and the oil pump cover is formed by dispersing at least a part of the sliding portion with ceramic particles. The gist of the invention is to form a predetermined shape from a mold aluminum-based composite material, arrange the sliding portion in the mold, and cast in the aluminum alloy.

According to the third aspect of the present invention, when at least one of the oil pump body and the oil pump cover is formed, at least a part of the sliding portion which the gear abuts and slides on is formed by dispersing ceramic particles. An oil pump having the function of the invention according to claim 1 is obtained by forming a predetermined shape from a mold aluminum-based composite material, arranging the sliding portion in the mold, and casting it with an aluminum alloy. . Also, when manufacturing an oil pump, without using a high-pressure mold casting method as in the prior art, gravity mold casting method,
The oil pump can be manufactured by a low-pressure mold casting method and a sand mold casting method, and the applicable range of the manufacturing method is wide.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a sectional view showing an oil pump according to the present embodiment. The oil pump according to the present embodiment is for supplying oil to a torque converter incorporated in an automatic transmission (automatic transmission), lubricating a planetary gear unit, and supplying a working hydraulic pressure for hydraulic control.

As shown in FIG. 1, the oil pump 11
A disk-shaped oil pump body 12 and a disk-shaped oil pump cover 13 smaller in diameter than the oil pump body 12
, A shaft 14, a drive gear 15, a driven gear 16, and the like. The shaft 14 is inserted through the oil pump body 12 and the oil pump cover 13, and the drive gear 15 and the driven gear 16 are set inside the oil pump body 12 and the oil pump cover 13. The oil pump cover 13 is fixed by bolts 17.

The oil pump body 12 has a main body portion 12a made of an aluminum alloy (JIS AC4C) and a sliding portion 12b made of a ceramic particle dispersed type aluminum-based composite material disposed inside the main body portion 12a. ing. The ceramic particle-dispersed aluminum-based composite material in the present embodiment is an aluminum alloy (JIS AC4C) as a metal base material (matrix).
And, containing silicon carbide particles as a reinforcing material,
In the aluminum alloy, 20% by volume of silicon carbide particles are dispersed in a volume ratio. The silicon carbide particles have a particle size of 5 μm to 40 μm, and the average particle size is 1 μm.
2.8 μm.

The sliding portion 12b is a portion to which the drive gear 15 or the driven gear 16 slides upon contact. The sliding portion 12b is formed with a crescent portion 12c which hangs down toward the oil pump cover 13. The crescent portion 12c is generally a portion where erosion due to cavitation or the like is likely to occur.

The oil pump cover 13 is made of an aluminum alloy (JIS AC4C), like the main body 12a of the oil pump body 12. The oil pump cover 13 includes a main body 13 a separated from the drive gear 15 or the driven gear 16 and the drive gear 1.
5 or sliding portion 13 against which driven gear 16 slides
b.

The drive gear 15 is driven by an engine (not shown) together with a pump impeller (not shown) of a torque converter (not shown), and plays a role of supplying a required hydraulic pressure at low speed to high speed and at the time of reverse. Has become. The hydraulic oil is set to increase in pressure by the contraction of the space volume inside the oil pump 11 formed by the drive gear 15 and the driven gear 16.

Now, a method of manufacturing the oil pump according to the present embodiment will be described below.

To form the oil pump body 12,
First, the above-described ceramic particle-dispersed aluminum-based composite material is melted at a temperature of 750 ° C. to form a melt, and the melt is poured into a mold and solidified to obtain a sliding portion 12 b of the oil pump body 12. . Next, the sliding portion 12
The sliding portion 12b is solidified by pouring and solidifying an aluminum alloy (JIS AC4C) in a state in which the sliding portion 12b is set at a predetermined position in the mold.
C4C) oil pump body 1 of predetermined shape
Get 2. Further, the oil pump cover 13 is formed in a predetermined shape by a die casting method, and a shaft 14, a drive gear 15, and a driven gear 16 are prepared.

As shown in FIG. 1, the sliding portion 1 of the oil pump body 12 and the oil pump cover 13
With the drive gear 15 and the driven gear 16 set inside the oil pump body 12 and the oil pump cover 13 and the shaft 14 inserted through the oil pump cover 13, the oil pump cover 13 is attached to the oil pump body 12 with bolts 17. By attaching and fixing, the oil pump 11 is manufactured.

According to the embodiment described above, the following effects can be obtained.

In the present embodiment, the sliding portion 12b of the oil pump body 12 is formed of a ceramic particle-dispersed aluminum-based composite material. For this reason, even when the drive gear 15 or the driven gear 16 abuts on the sliding portion 12b where a part of the silicon carbide particles is exposed and slides, it is possible to reduce the possibility that the gear is damaged as in the related art. Can be. That is, while the end portion of the ceramic fiber according to the related art has a sharp portion, the silicon carbide particle according to the present embodiment has a curved portion, so that a part of the silicon carbide particle is used. Drive gear 1
Even when the gear 5 or the driven gear 16 abuts and slides,
The drive gear 15 or the driven gear 16 is hardly damaged or the like, and the abrasion resistance of the sliding portion 12b can be less likely to be extremely reduced as in the related art.

According to the present embodiment, the possibility that the wear resistance of the sliding portion 12b is extremely reduced can be reduced, so that the sliding of the oil pump body 12 can be reduced as compared with the prior art. The wear resistance of the portion 12b can be further improved, and the occurrence and progress of erosion of the sliding portion 12b can be suppressed.

According to the present embodiment, since the occurrence and progress of erosion in the sliding portion 12b of the oil pump body 12 can be suppressed, the durability and reliability of the oil pump body 12, and thus the oil pump 11, can be improved. Can be planned. Therefore, it is possible to maintain the function of the oil pump 11 in a stable state for a long period of time.

The ceramic particle-dispersed aluminum-based composite material containing silicon carbide particles according to the present embodiment is less expensive than the ceramic fiber material according to the prior art. An increase in the manufacturing cost of the pump 11 can be prevented.

According to the present embodiment, since the particle size of silicon carbide particles in the ceramic particle-dispersed aluminum-based composite material is set in the range of 5 μm to 40 μm, sliding portion 12 b of oil pump body 12 In this case, it is possible to reliably prevent an extreme decrease in wear resistance.

According to the present embodiment, the oil pump 1
1 (oil pump body 12 and oil pump cover 1
When manufacturing 3), the oil pump 11 can be manufactured by gravity mold casting without using a high-pressure mold casting method as in the prior art, and the applicable range of the manufacturing method can be widened. it can.

According to the present embodiment, the crescent portion 12c, in which erosion is generally likely to occur, is formed of a ceramic particle-dispersed aluminum-based composite material, and the abrasion resistance of the crescent portion 12c is smaller than that of the prior art. Therefore, generation and progress of erosion in the crescent portion 12c can be suppressed.

According to the present embodiment, the performance of the oil pump made of a cast iron material (particularly, wear resistance in sliding parts)
It is possible to obtain the oil pump 11 which is not inferior to the oil pump.

The above-described embodiment can be modified as follows.

In the above embodiment, the sliding portion 12b of the oil pump body 12 is formed of the ceramic particle-dispersed aluminum-based composite material, but only a part of the sliding portion 12b is formed of the ceramic particle-dispersed aluminum-based composite material. Or the sliding portion 12b may be formed from two or more members.

The sliding portion 1 of the oil pump cover 13
At least a portion of 3b may be formed of a ceramic particle-dispersed aluminum-based composite material. For example, the entire sliding portion 13b of the oil pump cover 13 is formed of a ceramic particle dispersed aluminum-based composite material, or only a part of the sliding portion 13b of the oil pump cover 13 is formed of a ceramic particle dispersed aluminum-based composite material. Or may be formed.

In short, it is only necessary that at least a part of the sliding portions 12b, 13b of the oil pump body 12 and the oil pump cover 13 be formed of a ceramic particle-dispersed aluminum-based composite material.

In the above embodiment, a material containing an aluminum alloy (JIS AC4C) as a metal base material and silicon carbide particles as a reinforcing material was adopted as the ceramic particle dispersed type aluminum-based composite material.
In particular, it is not limited to the materials of the above-described embodiment.
For example, an aluminum alloy (JISA) as a metal base material
A material containing C9C) and ceramic particles such as alumina particles and zirconia particles as a reinforcing material may be employed.

In the above embodiment, the particle size of the silicon carbide particles as the reinforcing material is set in the range of 5 μm to 40 μm.
It is not particularly limited to the above range. That is, the particle size of the ceramic particles in the ceramic particle-dispersed aluminum-based composite material may be any size.

In the above embodiment, the oil pump 11 (the oil pump body 12 and the oil pump cover 13) is formed by gravity die casting, but these are formed by, for example, low pressure die casting, high pressure die casting, It may be formed by a sand casting method or the like.

In the above embodiment, the oil pump 11
(Oil pump body 12 and oil pump cover 1
Although a mold was used in the production of 3), a sand mold may be used.

[0042]

EXAMPLES Hereinafter, Example 1, which further embodies the present invention,
And Comparative Examples 1 to 3 according to the related art will be described.

(Example 1) In Example 1, the oil pump 11 according to the above embodiment was used as an oil pump. Then, as an operation durability test of the oil pump 11,
The gear of the oil pump 11 was operated at 8000 rpm for 200 hours, and the erosion generation area (square millimeter) in the crescent portion 12c of the oil pump 11 under the operating conditions was evaluated. In addition, the oil temperature in the oil pump 11 was controlled within the range of 115 ° C. to 125 ° C., and the oil pressure was controlled to be 1 MPa. Table 1 shows the results.

Comparative Example 1 In Comparative Example 1, an oil pump was used instead of the oil pump body 12 of Example 1.
An oil pump body formed of a wear-resistant aluminum alloy (JISAC9C) according to the prior art was used. The oil pump body of Comparative Example 2 is the same as that of Example 1
Is formed to have the same shape as the oil pump body 12. Then, the crescent portion of the oil pump of Comparative Example 1 was evaluated by the same method as the evaluation method of Example 1. Table 1 shows the results.

Comparative Example 2 In Comparative Example 2, an oil pump according to the prior art disclosed in Japanese Utility Model Publication No. 3-15832 (in which ceramic fibers are dispersed in a sliding portion) was used as an oil pump. The oil pump of Comparative Example 2 is formed to have the same shape as the oil pump of Example 1. Then, the crescent portion of the oil pump of Comparative Example 2 was evaluated by the same method as the evaluation method of Example 1. Table 1 shows the results.

Comparative Example 3 In Comparative Example 3, an oil pump was used instead of the oil pump body 12 of Example 1.
The oil pump body is made of gray cast iron (JI
SFC200). The oil pump body of Comparative Example 3 is formed to have the same shape as the oil pump body 12 of Example 1. Then, the oil pump of Comparative Example 3 was evaluated by the same method as the evaluation method of Example 1. Table 1 shows the results.

[0047]

【table 1】

As shown in Table 1, the erosion generation area in the crescent portion of the oil pump was determined in Example 1.
Is 4 square millimeters, and in Comparative Example 1, 18
Square millimeter, and in Comparative Example 2, it was 11 square millimeters. From this, it was confirmed that generation and progress of erosion in the crescent portion 21 of Example 1 were suppressed as compared with Comparative Example 1 and Comparative Example 2. That is, the wear resistance of the crescent portion 21 of Example 1 is dramatically improved compared to the wear resistance of the crescent portions of Comparative Example 1 and Comparative Example 2 (2.75).
Times or 4.5 times).

Since the erosion area of Example 1 is almost the same as the erosion area of 5 mm 2 of Comparative Example 3, the oil pump body 12 of Example 1 is made of gray cast iron (cast iron material). It was confirmed that it had abrasion resistance equal to or higher than that of the oil pump body. From the above, it was found that forming the sliding portion 12b (particularly the crescent portion 12c) of the oil pump body 12 with the ceramic particle-dispersed aluminum-based composite material was extremely effective in terms of wear resistance. .

Furthermore, technical ideas that are not described in the claims and that are grasped from the embodiments and the like will be described below together with their effects.

(A) An oil pump body made of an aluminum alloy and an oil pump cover also made of an aluminum alloy attached to the oil pump body, and a gear is provided on each sliding portion of the oil pump body and the oil pump cover. In the method of manufacturing an oil pump that slides while contacting, when forming at least one of the oil pump body and the oil pump cover, at least one of the sliding portions of the oil pump body and the oil pump cover is formed of ceramic particles. A manufacturing method of an oil pump, comprising forming a predetermined shape from a ceramic particle-dispersed aluminum-based composite material having a particle size of 5 μm to 40 μm, placing the sliding portion in a mold, and casting with an aluminum alloy. Method.

In this way, it is possible to obtain an oil pump having a sliding portion having excellent wear resistance.

[0053]

According to the first aspect of the present invention, the generation and progress of erosion can be suppressed by further improving the wear resistance of the sliding portion of the oil pump, and the production cost of the oil pump can be reduced. An increase can be prevented.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in (1), extreme reduction in wear resistance of the sliding portion of the oil pump body can be reliably prevented.

According to the third aspect of the invention, the generation and progress of erosion can be suppressed by further improving the wear resistance of the sliding portion of the oil pump.
An oil pump that can prevent an increase in manufacturing cost can be obtained. In addition, the manufacturing method of the oil pump can be applied not only to the high-pressure die casting method but also to the gravity die casting method, the low-pressure die casting method, and the sand die casting method, so that the applicable range of the manufacturing method can be widened. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an oil pump according to one embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Oil pump 12 Oil pump body 12a Main part 12b Sliding part 12c Crescent part 13 Oil pump cover 13a Main part 13b Sliding part 15 Drive gear 16 Driven gear

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H041 AA02 BB03 CC13 CC15 DD03 DD04 DD05 DD07 DD33 3H044 AA02 BB03 CC12 CC14 DD03 DD04 DD05 DD06 DD23 3H071 AA03 BB02 CC26 EE01

Claims (3)

[Claims] An oil pump body made of an aluminum alloy, and an oil pump cover also made of an aluminum alloy and attached to the oil pump body,
An oil pump in which a gear abuts each sliding portion of an oil pump body and an oil pump cover, wherein at least a part of the sliding portion is formed of a ceramic particle-dispersed aluminum-based composite material. And an oil pump. 2. The oil pump body according to claim 1, wherein the sliding portion of the oil pump body is formed of a ceramic particle-dispersed aluminum-based composite material having a ceramic particle size of 5 μm to 40 μm. Oil pump. 3. An oil pump body made of an aluminum alloy, and an oil pump cover also made of an aluminum alloy attached to the oil pump body,
In a method for manufacturing an oil pump in which a gear abuts on each sliding portion of an oil pump body and an oil pump cover to slide, when forming at least one of the oil pump body and the oil pump cover, the sliding portion is formed. Wherein at least a part of the oil pump is formed into a predetermined shape with a ceramic particle-dispersed aluminum-based composite material, and the sliding portion is disposed in a mold and cast with an aluminum alloy.