JPH03286114A - Twin oil pump - Google Patents

Abstract

PURPOSE:To reduce pulses and suppress generation of noises by locating two oil pumps in such a positional relation that the projection of the tooth of one oil pump coincides with the recession of the tooth of the other oil pump in phases of rotational angles. CONSTITUTION:Two trochoid oil pumps 2, 4 having the same type and volume are arranged to press-feed lubricating oil to each part of an engine. The two oil pumps 2, 4 are arranged in such a positional relation that the projection of the tooth for forming the inner rotor of one oil pump coincides with the recession of the tooth for forming the inner rotor of the other oil pump in phases of rotational angles. Pulses of the oil pumps 2, 4 are counterbalanced with each other and reduced, so that the oil is press-fed with almost no pulse. It is therefore possible to suppress the shock applied to an oil filter 11 caused by the pulses, and reduce oscillation and noises of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil pump for engine lubrication, and more particularly to improving hydraulic pulsation in a trochoidal oil pump (also referred to as a rotary pump).

[Conventional technology]

FIG. 5 shows an example of an engine lubrication path of a conventional engine lubrication oil pump. In the diagram, 20 is the oil pan, 2
1 is an oil strainer, 22 is an oil pump, 10 is a check valve, 11 is an oil filter, 12 is a main hole, and when the oil pump 22 is driven, the oil in the oil pan 20 of the engine flows into the oil pipe along the arrow shown in the figure. Oil flows through the main oil hole 12 and is pumped to each part of the engine for lubrication. There are various types of oil pumps used at this time, but the trochoid type oil pump 22 is often used, and FIG. 6 shows its main body and its operating process. As shown in the figure, this consists of an inner rotor 23, an outer rotor 24, and a pump shaft 25. It is fed under pressure as it rotates in the direction of the arrow, and is discharged to the outside from the discharge port 28 to be fed under pressure to each lubricating site. 69. The oil sucked into the pump chamber 29 through the suction port 27 in FIG. 69 (a) passes through the state shown in FIG. 6(b) and is then discharged to the outside from the discharge port 28 as shown in FIG.

[Problem to be solved by the invention]

The trochoid type gear pump shown in Fig. 6 is a trochoid with four leaves and five nodes, the inner rotor (also called small gear) 23 has four blades (teeth), and the outer rotor (also called large gear) 24 has five nodes (teeth). This shows the case of a pump. During operation, both the inner rotor 23 and the outer rotor 24 rotate in the same direction as shown in the figure, and the suction and discharge of oil is performed by one shaft of the pump shaft 25.
Suction and discharge are repeated a number of times equal to the number of blades of the inner rotor 23 per rotation, that is, four times, and the oil is pumped. Therefore, the pumped oil is transferred to the inner rotor shaft, i.e.
Oil is supplied to each part of the engine while pulsating the oil pressure at regular intervals four times per revolution of the pump shaft 25. FIG. 4 shows the state of this pulsation. That is, when the oil pump oil pressure is P, oil pressure pulsations of ±ΔP1 always occur in the oil pipe, which impacts the inner wall of the oil filter 11 and generates noise. In addition to the above-mentioned four-leaf type, the inner rotor has five-leaf or six-leaf types, and in this case, the greater the number of blades, the greater the number of pulsations per revolution of the pump shaft. , the strength of pulsation, i.e. △P1
is small and the height of the mountain is lowered to some extent, but the pulsation cannot be eliminated. Also, as the number of leaves increases, the structure becomes more complex.

In view of the above-mentioned problems, it is an object of the present invention to provide a means that has a simple structure, and that greatly reduces the above-mentioned pulsation and suppresses the generation of noise.

[Means to solve the problem]

In order to achieve the above object, in the present invention, two trochoidal oil pumps of the same type and capacity are provided in an engine lubricating system that pumps lubricating oil to various parts of the engine using a trochoidal oil pump. Regarding the two oil pumps, the relative positions of both pumps are adjusted so that the rotational angle phases of the peaks of the tooth profile forming the inner rotor of one pump and the valleys of the tooth profile forming the inner rotor of the other pump match. Set. Furthermore, both oil feed pipes from the oil strainer to both pumps and from the discharge ports of both pumps to the confluence point of the oil exiting both pumps are connected in parallel by two oil feed pipes with the same inner diameter and length. The Company provides a twin oil pump for engine lubrication featuring the following features:

[For production]

When operation starts, the two oil pumps start operating at the same time, and hydraulic pulsations occur separately in the oil feed pipes of the two oil pump systems arranged in parallel. At the merging point, the oil pressure pulsations match to form a combined pulsation, and the oil is pumped to each part of the engine via the oil filter. At this time, the relative positions of both pumps are set so that the peak of the pulsation coming from one oil pump matches the trough of the pulsation coming from the other oil pump, so the pulsation of both is canceled out and reduced. is,
The oil is pumped without pulsation, which reduces the impact of pulsations on the oil filter, reducing engine vibration and noise.

〔Example〕

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

FIG. 1 shows a layout diagram of an engine lubrication path set based on the present invention. The same parts as in FIG. 5 are given the same numbers. This device is equipped with two trochoidal oil pumps, instead of one in the past, and creates a time difference (phase difference) between the pressures of the oil sent out from the two oil pumps in the two lines of oil pipes to increase the oil pressure. The pulsation is suppressed.

In other words, the oil in the oil pan 20 is transmitted through one oil pipe system: the first oil strainer 1, the first oil pipe 5.
The remaining oil is drawn up by the second oil pump 4 through the second oil strainer 3 and the second oil pipe 7, and is sucked up by the second oil hole 8. The oil that has flowed in parallel through these two lines joins at the oil hole merging section 9, passes through the oil filter 11, and enters the main oil hole 12.
From there, it is distributed to various parts of the engine for lubricating purposes. 10 is a check valve. In the above two parallel oil supply paths, the first oil strainer 1
and the second oil strainer 3 and the first oil pump 2
and the second oil pump 4 are of the same type, respectively.
They have the same capacity, and the first oil vibe 5 and the second oil vibe
It is assumed that the oil pipe 7 and the first oil hole 6 and the second oil hole 8 each have the same inner diameter and length.

In the arrangement having the above structure and function, the oil pumps 2 and 4 in this embodiment use two trochoidal oil pumps with four inner rotors (four teeth) as shown in FIG. The pump shown in FIG. 2 has the same structure and operation as the conventional pump shown in FIG. 6, so the same parts are given the same numbers and detailed explanations will be omitted.

The inner rotor 23 and the outer rotor 24 are mounted eccentrically within the pump body 26, and as they rotate in the same direction as shown by the arrows, the spatial volume of the pump chamber 29 changes, and the oil sucked into the pump chamber 29 from the suction port 27 is It is discharged from the discharge port 28.

When two of the above-described trochoidal oil pumps are assembled into an engine, the phases of the rotational angles of the inner rotors of both the first and second pumps are shifted from each other by a predetermined angle.

To give an example of an assembly method for this purpose, first, the bodies of both oil pumps and the crankcase are arranged so that they are in the same position. For example, for the first oil pump 2, there are reference lines X, -X passing through the pump axis 01, and reference lines Y, -Y perpendicular thereto.

is set perpendicular to the pump shaft, and the line connecting the center of the flange bolt hole 31 of the pump body 26, for example, the center of the flange bolt hole 31 and the pump shaft center 01 in FIG. Positioning is performed so that the angles α and β are controlled at l and -'f, respectively.

On the other hand, in order to arrange the second oil pump 4 in the same position as the first oil pump within the crankcase, the pump shaft 25 of the second oil pump 4 must be connected to the pump shaft 25 of the first oil pump 2. A reference line X2 passing through the axis 02 of this second oil pump
A specific flange bolt hole 31 is set so that X2, Y2 and Y2 are parallel to the reference lines X, Y, and -Y, respectively, and is drilled in a similar shape to the bolt hole of the first oil pump. The position of is the reference line X2 Xz,
For Yz Y2, α and β are respectively set in the same manner as above.
The position of the pump body 26 is determined so that the angle of .

This places both pumps in the same position within the crankcase.

Next, in order to shift the phase of the rotational angle of the inner rotor 23 in both pumps by a predetermined angle θ, let Z be the number of teeth (number of blades) of the inner rotor of the pump, and set θ so that the relationship is as follows. decide. Therefore, in the case of a four-blade innertrochoid as in this example, θ=45°
becomes. Referring to FIG. 2, the bottom 23 of the tooth profile forming the inner rotor 23 of the first oil pump 2. coincides with the reference line Y+ Y+, but at this time, for the second oil pump 4, the term 23. of the tooth profile of the inner rotor 23. coincides with the reference line Y2 Y2. Therefore, regarding the rotation of the inner rotor, there is always a phase difference of θ=45° between the first oil pump and the second oil pump, and the rotation continues with the phases of the peaks and valleys of each tooth profile matching.

By using the above method, the phase difference between the two pumps can be adjusted.
When the rotating teeth are assembled so that the peaks of one tooth profile and the valleys of the other tooth profile match, the pulsation of oil pressure in the oil pipe below the oil hole confluence section 9, which occurs as a result, is caused by the first pump 2
If the π phase shift between the pump 4 and the second pump 4 exactly matches the above θ=, the pulsation caused by the first pump and the pulsation caused by the
The pulsation (2) caused by the pump cancels each other out to form the pulsation (2), and this pulsation is theoretically zero. In reality, considering that there are some errors in assembly due to timing, it is possible that some pulsation may remain, but with this method, the number of blades in the conventional pump can be reduced from 4 to 5 or 6. Since a completely different principle is applied to the reduction of pulsation due to an increase in the number of pulses, etc., the effect of eliminating pulsation is large, and the occurrence of pulsation is close to zero, making it possible to significantly reduce the pulsation.

In addition, even if there is a slight error as mentioned above and pulsation remains, the number of oil pumps increases and the number of pulsations increases accordingly, resulting in a higher frequency of noise. The level of perceived noise will be lower. In addition, since two oil pumps are installed, the oil discharge amount (capacity) per pump can be small, making it possible to downsize the oil pump. The height ±ΔP2 is lower than the pulsation height ±Δp+ (FIG. 4) in the case of one conventional pump, which helps reduce noise. Furthermore, as the pump becomes smaller, the load for driving the pump becomes smaller, and the pulsations generated to drive the pump are also dispersed and reduced.

Although a trochoid pump with 4 leaves and 5 nodes has been described above, the present invention is not limited to this, and the present invention is not limited to this. also applies.

〔Effect of the invention〕

By implementing the present invention, the following effects can be achieved.

(1) Vibration and noise of the engine are reduced by offsetting and reducing the pulsation of the oil pressure generated in the oil pipe of the oil pumped by the oil pump.

(2) By increasing the number of oil pumps, the number of pulsations of the oil pumps increases, and the frequency of the noise increases, so the degree to which the human body senses the noise decreases.

(3) By increasing the number of oil pumps, it is possible to make the oil pumps smaller and lighter. Additionally, this reduces the maximum value of the pulsating oil pressure of one oil pump, contributing to noise reduction.

[Brief explanation of the drawing]

Fig. 1 is a layout diagram of the lubrication path by the twin oil pump according to the present invention, Fig. 2 is a sectional view of the main body of the trochoidal oil pump used above, and Fig. 3 is the inside of the oil feed pipe when the twin oil pump is used. Fig. 4 is a hydraulic pressure-time diagram showing the pulsating state of the oil pressure in the oil supply pipe when one conventional oil pump is used; FIG. 6 shows an operational diagram of a conventional trochoidal oil pump. 1.3.21...Oil strainer, 2.4.22.
... Trochoid oil pump, 9... Oil confluence point, 23... Inner rotor, 24... Outer rotor. 0 Fig. 1 1.3・Oil filter 2.4 Oil pump 5.7 Oil hole RO, 8・Oil hole 9・・Confluence part 11・・Oil filter 12・・・Main oil hole 20 Oil pan 01.02・・・・Pump shaft center (Yl) Yl Fig. 2 Inner rotor Outer rotor Pump shaft Pump body Suction port Discharge pump chamber Bolt hole

Claims (1)

[Claims] 1. In an engine lubricating system that pumps lubricating oil to various parts of the engine using a trochoidal oil pump, two trochoidal oil pumps of the same type and capacity are provided, and the two trochoidal oil pumps are Regarding the oil pumps, the relative positions of both pumps were set and arranged so that the rotational angle phase of the peaks of the tooth profile forming the inner rotor of one pump and the valleys of the tooth profile forming the inner rotor of the other pump matched. A twin oil pump for engine lubrication characterized by: 2. From the oil strainer to the two oil pumps, and from the discharge ports of the two oil pumps to the meeting point of the oil coming out of both pumps, the inner diameter and length are equal.
2. The twin oil pump for engine lubrication according to claim 1, wherein the twin oil pumps are connected in parallel by two oil feed pipes.