Patent Application
20210355940
This application claims the benefit of Korean Patent Application No. 10-2020-0058945, filed in the Korean Intellectual Property Office on May 18, 2020, which application is hereby incorporated herein by reference.
The present invention relates to a hydraulic pump for a vehicle.
A general hydraulic pump is supplied with oil from an oil pan through an inlet port and generates high-pressure oil through rotation of a rotor and exhausts it through an outlet port.
The oil pressure of the periodic pulsating waveform is formed on the outlet port of the hydraulic pump by the hydraulic pump rotating at high speed and high pressure. Noise occurs due to the pulsating pressure component, and this is called high-speed noise (whine noise).
The noise generated by the hydraulic pump affects even the vehicle interior through a chain cover adjacent to the hydraulic pump.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
The present invention relates to a hydraulic pump for a vehicle. Particular embodiments relate to a hydraulic pump for a vehicle capable of reducing whine noise by reducing pulsation pressure.
Embodiments of the present invention provide a hydraulic pump for a vehicle capable of reducing whine noise through reduction of pulsation pressure.
A hydraulic pump for a vehicle according to an exemplary embodiment of the present invention may include a pump housing of which an inlet port is formed thereto, a chain cover combined with the pump housing and forming an outlet port with the pump housing, and a rotor including an inner gear and an outer gear, provided between the pump housing and the chain cover, and having a predetermined thickness and wherein the outlet port includes a center port having the same thickness of the rotor, a housing port formed to the pump housing and having a first depth and a cover port formed to the chain cover and having a second depth, and wherein the sum of the first depth and the second depth is 50% to 60% of the rotor thickness.
The ratio of the first depth and the second depth may be 2:1 to 3:1.
The outlet port may be formed inclined in the direction of the inlet port at the end.
The inner gear and the outer gear may form a plurality of pockets, a notch that communicates with the outlet port may be formed in the pump housing, and the formation position of the notch may be the angle corresponding to the one pocket from the inlet port toward the outlet port and a position that is 5 degrees to 10 degrees apart based on the center of the rotor.
An end of the outlet port may be formed at 100 degrees to 120 degrees from the formation position of the notch based on the center of the rotor.
A length of the notch may be lo degrees to 15 degrees from the formation position of the notch, based on the center of the rotor.
A depth of the notch may be 2% to 5% of the rotor thickness.
A slope may be formed between the end of the notch and the outlet port and the slope may be is formed in a 30 degree to 60 degree angle.
A hydraulic pump for a vehicle according to an exemplary embodiment of the present invention may include a pump housing of which an inlet port is formed thereto, a chain cover combined with the pump housing and forming an outlet port with the pump housing, and a rotor including an inner gear and an outer gear, provided between the pump housing and the chain cover, and having a predetermined thickness and wherein a notch that communicates with the outlet port may be formed in the pump housing, and a slope may be formed between the end of the notch and the outlet port.
The outlet port may include a center port having the same thickness of the rotor, a housing port formed to the pump housing and having a first depth and a cover port formed to the chain cover and having a second depth, and the sum of the first depth and the second depth may be 50% to 60% of the rotor thickness.
The ratio of the first depth and the second depth may be 2:1 to 3:1.
The inner gear and the outer gear may form a plurality of pockets and the formation position of the notch may be the angle corresponding to the one pocket from the inlet port toward the outlet port and a position that is 5 degrees to 10 degrees apart based on the center of the rotor.
An end of the outlet port may be formed at 100 degrees to 120 degrees from the formation position of the notch based on the center of the rotor.
A length of the notch may be 10 degrees to 15 degrees from the formation position of the notch, based on the center of the rotor.
A depth of the notch may be 2% to 5% of the rotor thickness.
The slope may be formed in a 30 degree to 60 degree angle.
According to the hydraulic pump for a vehicle according to an exemplary embodiment of the present invention, it is possible to reduce whine noise by reducing pulsation pressure.
The following reference numerals can be used in conjunction with the drawings:
In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration.
As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
Parts indicated by the same reference number throughout the specification mean the same constituent elements.
In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.
When a part of a layer, film, region, plate, etc. is said to be “above” another part, this includes not only directly above the other part but also another part in the middle.
In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.
Throughout the specification and the claims, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
Exemplary embodiments of the present invention will hereinafter be described in detail with reference to the accompanying drawings.
A hydraulic pump 1 for a vehicle according to an exemplary embodiment of the present invention includes a pump housing 10 and a chain cover 50 coupled to the pump housing 10.
Referring to
An inlet port 12 through which oil is introduced is formed to the pump housing 10, and the pump housing 10 and the chain cover 50 form an outlet port 70 through which oil is exhausted.
The rotor 30 has a predetermined thickness T0, and the outlet port 70 includes a center port 72 having the same thickness as the rotor 30, a housing port 74 formed to the pump housing 10 and having a first depth T1 and a cover port 76 formed to the chain cover 50 and having a second depth T2.
The sum of the first depth T1 and the second depth T2 is 50% to 60% of the rotor thickness T0. When the sum of the first depth T1 and the second depth T2 is at least 50% of the rotor thickness T0, it is confirmed through an experiment that high-speed whine noise is reduced. For example, a typical rotor thickness is about 18-25 mm, and when the rotor thickness T0 is about 25 mm, the sum of the first depth T1 and the second depth T2 is formed to be at least 12.5 mm, thereby improving whine noise.
The ratio of the first depth T1 and the second depth T2 may be 2:1 to 3:1. For example, if the second depth T2 is 3.6 mm, the first depth T1 may be formed to about 90 mm.
The oil in the outlet port 70 is exhausted through outlet 90.
A notch 40 communicated with the outlet port 70 can be formed in the pump housing 10. It is confirmed through an experiment that the notch 40 can suppress noise generation.
If the formation start point of the notch 40 is applied too close to the inlet port 12, the charging efficiency of hydraulic pump 1 may decrease in a high-speed section where the rotation speed of the hydraulic pump 1 is high. On the other hand, if the formation start point of the notch 40 is formed too far from the inlet port 12, the pressure is not relieved quickly and the noise, vibration, and harshness (NVH) characteristics may be disadvantageous.
The inner gear 32 and the outer gear 34 form a plurality of pockets 36, increase the oil pressure by the pockets 36, and the start position of the notch 40 may be determined by the pockets 36.
The formation position of the notch 40 is the angle corresponding to the one pocket 36 from the inlet port 12 toward the outlet port 70 and a position (a) that is 5 degrees to 10 degrees apart based on the center C of the rotor 30.
In
That is, in the case of the hydraulic pump according to an exemplary embodiment of the present invention shown in the drawing, the formation start position a of the notch 40 may be a position separated from the inlet port 12 by about 56-61 degrees.
If the formation start point of the notch 40 is too close to the inlet port 12, the charging efficiency of the hydraulic pump 1 may decrease in the high-speed section where the rotation speed of the hydraulic pump 1 is high. On the other hand, if the formation start point of the notch 40 is formed too far from the inlet port 12, the pressure in the pocket 36 will not be relieved quickly and the NVH characteristics may be deteriorated. In the case of the hydraulic pump according to an exemplary embodiment of the present invention, the start position a of the notch 40 is a position 5 to 10 degrees further away from the end of the inlet port 12 than the angle of one pocket, thus the charging efficiency of the hydraulic pump 1 is maintained, and pressure in the pocket 36 can be smoothly relieved.
If a hydraulic pump has 10 pockets, the notch 40 can be started about 41-46 degrees from the inlet port 12.
In consideration of high pressure formation and noise reduction, the end of the outlet port 70 can be formed at loo degrees to 120 degrees (γ) from the formation position of the notch 40 based on the center of the rotor C.
A length L of the notch 40 may be 10 degrees to 15 degrees (β) from the formation position of the notch, based on the center of the rotor C. In consideration of the notch effect, the length (L) of the notch 40 can be formed at a level of 10-15% of the outlet port formation angle γ.
The depth of the notch can be 2% to 5% of the rotor thickness T0.
The capacity of the hydraulic pump is determined according to the rotor thickness. The notch depth can be proportional to the rotor thickness. However, if the notch thickness is too large, the notch effect can be reduced.
In an exemplary embodiment of the present invention, the depth T3 of the notch 40 is set to 2% to 5% of the rotor thickness T0, so that the NVH characteristics can be improved. For example, when the rotor thickness T0 is 25 mm, the minimum depth T3 of the notch 40 may be 0.5 mm.
A slope 45 is formed between the end of the notch 40 and the outlet port 70, and the slope 45 may be formed to be inclined by 30 degrees to 60 degrees.
The slope 45 connected to the notch 40 has a gentle slope, and the outlet poll 70 is processed to deepen. If the angle of formation of the slope 45 is too rapid (e.g., 90 degrees), it may be disadvantageous from the NVH side due to rapid flow space expansion, and the slope angle of the slope 45 can be formed to be inclined by 30 degrees to 60 degrees.
In describing the hydraulic pump for a vehicle according to a modified exemplary embodiment of the present invention of
An outlet port 80 of the hydraulic pump for a vehicle according to a modified exemplary embodiment of the present invention includes a center port 82 having the same thickness T0 of the rotor 30, a housing port 84 formed to the pump housing 10 and having a first depth T1 and a cover port 86 formed to the chain cover 50 and having a second depth T2. The sum of the first depth T1 and the second depth T2 is 50% to 60% of the rotor thickness T0.
Comparing to the hydraulic pump for a vehicle according to the exemplary embodiment of the present invention, the hydraulic pump for a vehicle according to a modified exemplary embodiment of the present invention does not include a notch, so that it does not have a notch effect, but its structure is simple and production cost can be reduced.
Here, the comparative specification is a comparison between a hydraulic pump of the same capacity and a hydraulic pump having a discharge pump of a different shape.
Compared to a general hydraulic pump (Base) for a vehicle, the hydraulic pump (A) for a vehicle according to a modified exemplary embodiment of the present invention that does not include a notch exhibits a relatively good noise characteristic. And it can be seen that the hydraulic pump (B) for a vehicle according to an exemplary embodiment of the present invention including a notch shows a relatively good noise characteristic compared to the hydraulic pump (A) for a vehicle according to a modified exemplary embodiment of the present invention.
As described above, the hydraulic pump for a vehicle according to the exemplary embodiment of the present invention can reduce pulsation pressure through shape change such as an outlet port, and thereby reduce whine noise.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0058945 | May 2020 | KR | national |
