JP6806337B2 - Inscribed gear pump - Google Patents

Description

The present invention relates to an internal gear pump.

The internal gear pump is used as an oil pump that supplies oil for lubricating an automobile engine or the like and operating a transmission or the like. As the oil pump, Patent Document 1 discloses a variable displacement pump in which the pump discharge amount is variable. In this variable displacement pump, an inner rotor having a plurality of outer teeth and an outer rotor having a plurality of internal teeth that mesh with the outer teeth are arranged eccentrically, and an adjusting ring that rotatably supports the outer rotor from the outer circumference thereof is provided. Has been done. When the pump discharge pressure (flood control) rises as the pump rotation speed increases, the adjustment ring rotates due to the action of the pump discharge pressure. The rotation causes the outer rotor to rotate with respect to the inner rotor. Then, the discharge volume from the pump chamber (chamber) between the outer teeth of the inner rotor and the inner teeth of the outer rotor to the discharge port is made smaller than before the discharge pressure rises, so that the amount of oil discharged can be reduced. The amount of oil discharged is reduced when the engine speed is high, which tends to be excessive.

Japanese Unexamined Patent Publication No. 2008-298026

By providing the adjusting ring, it is necessary to provide a mechanism for displacing the adjusting ring by the pump discharge pressure, and the structure of the inscribed gear pump tends to be complicated.

Therefore, one of the purposes is to provide an inscribed gear pump having a simple configuration and a variable discharge amount.

The internal gear pump according to the present disclosure is
A pump rotor having an inner rotor having outer teeth and an outer rotor having internal teeth meshing with the outer teeth and provided eccentrically with respect to the inner rotor.
A pump case having a rotor chamber for accommodating the pump rotor and a suction port and a discharge port opening in the rotor chamber.
A chamber formed between the outer teeth and the inner teeth and whose volume increases or decreases with the rotation of the inner rotor and the outer rotor to discharge oil sucked from the suction port from the discharge port.
An intake hole that opens into the intake port to send outside air,
It is provided with an outside air amount variable mechanism that opens and closes the intake hole to change the amount of outside air taken in by using the oil pressure of the oil discharged from the discharge port.

The internal gear pump has a simple structure and a variable discharge amount.

It is a top view which shows the outline of the internal gear pump which concerns on Embodiment 1. FIG. It is a top view which shows the outline of the pump case provided in the inscribed gear pump which concerns on Embodiment 1. FIG. It is a graph which shows the relationship between the pump rotation speed and the discharge pressure in various inscribed gear pumps. It is a graph which shows the relationship between the pump rotation speed and the drive torque in various inscribed gear pumps.

<< Explanation of Embodiments of the Present Invention >>
First, embodiments of the present invention will be listed and described.

(1) The internal gear pump according to one embodiment of the present invention is
A pump rotor having an inner rotor having outer teeth and an outer rotor having internal teeth meshing with the outer teeth and provided eccentrically with respect to the inner rotor.
A pump case having a rotor chamber for accommodating the pump rotor and a suction port and a discharge port opening in the rotor chamber.
A chamber formed between the outer teeth and the inner teeth and whose volume increases or decreases with the rotation of the inner rotor and the outer rotor to discharge oil sucked from the suction port from the discharge port.
An intake hole that opens into the intake port to send outside air,
It is provided with an outside air amount variable mechanism that opens and closes the intake hole to change the amount of outside air taken in by using the oil pressure of the oil discharged from the discharge port.

According to the above configuration, the discharge amount can be made variable by a simple configuration including an intake hole and an outside air amount variable mechanism for opening and closing the intake hole without using an adjustment ring. This is because the intake hole and the variable outside air amount mechanism can reduce the amount of oil sucked from the suction port by the amount of outside air taken into the rotor chamber from the intake hole, so that the amount of oil discharged from the discharge port can be reduced. Therefore, the oil discharge amount can be set to an appropriate amount so as not to be excessive at the time of high rotation of the engine where the oil discharge amount tends to be excessive. Therefore, the oil pressure (discharge pressure) can be reduced, and unnecessary pumping work of the inscribed gear pump can be reduced, so that the drive torque can be reduced.

(2) As one form of the inscribed gear pump, an oil supply hole is provided between the bottom surface of the rotor chamber and the end surface of the pump rotor to supply oil discharged from the discharge port by opening the rotor chamber. To prepare.

According to the above configuration, it is easy to suppress seizure between the bottom surface of the rotor chamber and the end surface of the pump rotor. When the outside air is taken in from the intake hole and the amount of oil sucked from the suction port is reduced, less oil is supplied between the bottom surface of the rotor chamber and the end face of the pump rotor, and the bottom surface of the rotor chamber and the pump rotor There is a risk of seizure with the end face. However, by providing the oil supply hole, oil can be replenished between the bottom surface of the rotor chamber and the end surface of the pump rotor.

<< Details of Embodiments of the present invention >>
Details of the embodiments of the present invention will be described below with reference to the drawings. The same reference numerals in the figures indicate the same names.

<< Embodiment 1 >>
[Inscribed gear pump]
The internal gear pump 1 according to the first embodiment will be described with reference to FIGS. 1 and 2. The inscribed gear pump 1 includes a pump rotor 2, a pump case 3, and a chamber 4. The pump rotor 2 has an inner rotor 21 and an outer rotor 22. The pump case 3 has a rotor chamber 31 for accommodating the pump rotor 2, and a suction port 32 and a discharge port 33 that open into the rotor chamber 31. The chamber 4 is a space between the inner rotor 21 and the outer rotor 22, and the oil sucked from the suction port 32 is discharged from the discharge port 33 by increasing or decreasing the volume thereof. One of the features of the internal gear pump 1 is the intake hole 5 that opens to the intake port 32 and sends the outside air (two-dot chain arrow in FIG. 2), and the oil pressure (discharge pressure) of the oil discharged from the discharge port 33. The point is that the outside air amount variable mechanism 6 (FIG. 2) for changing the amount of outside air taken in by opening and closing the intake hole 5 is provided. The details will be described below. For convenience of explanation, the pump case 3 is hatched in FIGS. 1 and 2.

[Pump rotor]
The pump rotor 2 is driven by the rotation of the engine and rotates to form a chamber 4 for transferring oil. The pump rotor 2 has an inner rotor 21 and an outer rotor 22. The inner rotor 21 has a plurality of external teeth 21a, and the outer rotor 22 has a plurality of internal teeth 22a that mesh with the external teeth 21a. The number of external teeth 21a is one less than the number of internal teeth 22a, and here, the number of external teeth 21a is eight and the number of internal teeth 22a is nine. A drive shaft 14 that is rotationally driven by an engine, a motor, or the like is connected to the center of the inner rotor 21, and the inner rotor 21 rotates when the drive shaft 14 is rotationally driven (clockwise in FIG. 1). The outer rotor 22 is provided eccentrically with respect to the inner rotor 21, and receives a driving force by engaging the outer teeth 21a of the inner rotor 21 and the inner teeth 22a of the outer rotor 22 by the rotation of the inner rotor 21. It follows the inner rotor 21 and rotates in the same direction. FIG. 1 shows a state in which the center of gravity (center of rotation) of the outer rotor 22 is shifted to the lower side of the paper surface of the center of gravity (center of rotation) of the inner rotor 21. Due to this eccentricity, a plurality of chambers 4 having a variable volume are formed between the outer teeth 21a and the inner teeth 22a. Since the rotation of the engine is transmitted to the pump rotor 2, the higher the rotation of the engine, the higher the rotation. As the pump rotor 2, for example, an iron-based sintered material, an aluminum-based sintered material, or the like can be used.

[Pump case]
The pump case 3 has a bottom surface 31b and a side surface, and each of these surfaces forms a rotor chamber 31 for accommodating the pump rotor 2. A suction port 32 and a discharge port 33 are opened in the rotor chamber 31, and a shaft hole 34 (FIG. 2) through which the drive shaft 14 is inserted and a refueling hole 7 described later are formed in the bottom surface 31b of the rotor chamber 31. It is formed. The suction port 32 is connected to a suction passage 12 (FIG. 2) connected to an oil pan (not shown), and guides oil from the suction passage 12 into the rotor chamber 31. The discharge port 33 is connected to a discharge path 13 (FIG. 2) connected to an engine, a transmission, or the like, and guides oil from the rotor chamber 31 to the discharge path 13. The shape of the suction port 32 and the discharge port 33 is an arc groove shape protruding toward the outside of the rotor chamber 31. The suction port 32 and the discharge port 33 are formed at positions where they overlap between the inner rotor 21 and the outer rotor 22. The start end of the suction port 32 and the end of the discharge port 33 (upper side of the paper in FIG. 1) are formed so as to be adjacent to each other, and the end of the suction port 32 and the start end of the discharge port 33 (lower side of the paper in FIG. 1) are mutually adjacent to each other. It is formed so as to be adjacent to each other. The starting end of the suction port 32 and the ending portion of the discharge port 33 are formed at positions where the volume of the chamber 4 is minimized (the upper side of the paper in FIGS. 1 and 2). The positions where the end of the suction port 32 and the start of the discharge port 33 are formed are the positions where the volume of the chamber 4 is maximized (the lower side of the paper in FIGS. 1 and 2). Of the bottom surface 31b of the rotor chamber 31, the portion between the end of the suction port 32 and the start end of the discharge port 33 is a confinement portion that seals the chamber 4.

[Chamber]
The chamber 4 is a space formed between the outer teeth 21a of the inner rotor 21 and the inner teeth 22a of the outer rotor 22. The number of chambers 4 is plural, and the volume of each chamber 4 increases or decreases as the inner rotor 21 and the outer rotor 22 rotate due to the eccentricity of the inner rotor 21 and the outer rotor 22. Since the chamber 4 becomes negative pressure in the region where its volume increases, oil is sucked from the suction port 32, and the chamber 4 is temporarily separated from the suction port 32 and the discharge port 33 at the position where the volume becomes maximum, and the volume decreases. The oil compressed in the region is discharged from the discharge port 33.

[Intake hole]
The intake hole 5 is a hole for taking in outside air (two-dot chain arrow in FIG. 2). The outside air becomes negative pressure in the chamber 4 due to the rotation of the pump rotor 2, and when the intake hole 5 is opened, the outside air automatically flows through the intake hole 5 and is taken into the suction port 32. Therefore, a separate means for pumping the outside air into the suction port 32 is not required. The taken-in outside air is sucked into the rotor chamber 31 from the suction port 32, mixed with the oil sucked from the suction port 32, and sucked into the chamber 4. The amount of oil sucked from the suction port 32 is reduced by the amount of outside air sucked in, and the amount of oil discharged from the discharge port 33 is reduced. The intake hole 5 is open to the outside of the intake port 32 and the internal gear pump 1. Here, the intake hole 5 is formed so as to penetrate the bottom surface 32b of the intake port 32. The intake hole 5 is formed on the starting end side of the intake port 32 (upper of FIGS. 1 and 2) of the bottom surface 32b of the intake port 32. As a result, it is easy to effectively inhale the outside air into the chamber 4.

[Variable outside air volume mechanism]
The outside air amount variable mechanism 6 opens and closes the intake hole 5 to change the amount of outside air taken into the intake port 32 (FIG. 2). By making the amount of outside air taken in variable, the amount of oil sucked can be adjusted so that the amount of oil discharged does not become excessive at high speeds of the engine where the amount of oil discharged tends to be excessive. As a result, the oil pressure (discharge pressure) can be reduced, and unnecessary pumping work of the internal gear pump 1 can be reduced, so that the drive torque can be reduced. Therefore, since the mechanical efficiency can be increased, the efficiency of the internal gear pump 1 can be increased. A part of the oil pressure discharged from the discharge port 33 is used to open and close the intake hole 5. That is, the outside air amount variable mechanism 6 mechanically opens and closes the intake hole 5 by using the electric pressure.

The outside air amount variable mechanism 6 may open (fully open) or close (fully close) the intake hole 5 with a predetermined oil pressure as a boundary, and adjusts the opening amount of the intake hole 5 in conjunction with the fluctuation of the oil pressure. You may. In the former case, the intake hole 5 is closed (fully closed) so that the amount of outside air becomes zero when the pressure is below the predetermined pressure, and the intake hole 5 is opened so that the outside air is sent when the pressure exceeds the predetermined pressure. (Fully open) can be mentioned. In the latter case, as the oil pressure rises, the opening degree of the intake hole 5 is increased to increase the amount of outside air sent. The opening of the intake hole 5 may be started at a time when the pressure exceeds a predetermined level. This oil pressure can be measured by providing a hydraulic circuit that utilizes the oil pressure of the internal gear pump 1 or an oil pressure gauge (not shown) at an appropriate position upstream of the outside air amount variable mechanism 6.

The outside air amount variable mechanism 6 may include, for example, a valve mechanism (not shown) that is displaced by flood control. The valve mechanism is provided so as to open the intake hole 5 to take in outside air when the predetermined oil pressure is exceeded. In addition to the valve mechanism, the outside air amount variable mechanism 6 may include an outside air introduction path (not shown) that is connected to the intake hole 5 and introduces outside air into the intake hole 5. In that case, the valve mechanism may be provided so as to open and close the outside air introduction path when the predetermined hydraulic pressure is exceeded. This valve mechanism may be shared with the valve mechanism provided in the oil circulation mechanism 8 described later. Then, the opening and closing of the intake hole 5 and the supply / stop of the oil to the oil supply hole 7 can be easily linked. Of course, the valve mechanism of the outside air amount variable mechanism 6 may be independent of the valve mechanism of the oil circulation mechanism 8. The valve mechanism includes, for example, a relief valve.

[Refueling hole]
The inscribed gear pump 1 is preferably provided with an oil supply hole 7 that opens into the rotor chamber 31 and supplies oil discharged from the discharge port 33 between the bottom surface 31b of the rotor chamber 31 and the end surface of the pump rotor 2. .. By supplying this oil, it is easy to suppress seizure between the bottom surface 31b of the rotor chamber 31 and the end surface of the pump rotor 2. When the outside air is taken in from the intake hole 5 and the amount of oil sucked from the suction port 32 is reduced, the amount of oil supplied between the bottom surface 31b of the rotor chamber 31 and the end surface of the pump rotor 2 is reduced, and the rotor chamber 31 There is a risk that the bottom surface 31b of the pump rotor 2 and the end surface of the pump rotor 2 will seize. However, by providing the oil supply hole 7, oil can be replenished between the bottom surface 31b of the rotor chamber 31 and the end surface of the pump rotor 2.

The location where the lubrication hole 7 is formed includes the bottom surface 31b of the rotor chamber 31, and the opening portion of the lubrication hole 7 may be a portion of the bottom surface 31b that faces the end surface of the outer rotor 22. It is preferable that the portion faces the end face of 21 (FIG. 1). By doing so, it is considered that seizure between the bottom surface 31b of the rotor chamber 31 and the end surface of the inner rotor 21 where seizure is likely to occur can be easily suppressed. Oil in the chamber 4 or the like is easily supplied by centrifugal force between the end surface of the outer rotor 22 and the end surface of the rotor chamber 31. The opening of the oil supply hole 7 is the suction port 32 side of the portions of the bottom surface 31b of the rotor chamber 31 facing the end surface of the inner rotor 21. By doing so, it is easy to suppress the seizure on the suction port 32 side on the bottom surface 31b of the rotor chamber 31, which is particularly prone to seizure.

[Oil circulation mechanism]
The internal gear pump 1 preferably includes an oil circulation mechanism 8 that circulates the oil discharged from the discharge port 33 to the oil supply hole 7 (FIG. 2). The oil circulation utilizes a part of the oil pressure discharged from the discharge port 33. That is, the oil circulation mechanism 8 mechanically circulates the oil through the oil supply holes 7 by using the oil pressure.

The oil circulation mechanism 8 may include, for example, a branch passage 81 for circulating oil flowing through the discharge passage 13 to the oil supply hole 7, and a valve mechanism (not shown) that is displaced by flood control. The valve mechanism is provided so as to open the branch path 81 and divert the oil flowing through the discharge path 13 to the branch path 81 when the predetermined oil pressure is exceeded. As described above, this valve mechanism can be shared with the outside air amount variable mechanism 6 or can be independent of the outside air amount variable mechanism 6. When the oil circulation mechanism 8 communicates with the discharge path 13 and provides a circulation path (not shown) for returning excess oil to the suction path 12 or the oil pan, the branch path 81 is in the middle of the circulation path and the oil supply hole. It may communicate with 7 or directly communicate with the discharge path 13 and the oil supply hole 7.

[Action effect]
According to the internal gear pump 1 according to the first embodiment, the oil discharge amount is variable with a simple configuration including an intake hole 5 and an outside air amount variable mechanism 6. This is because by sending outside air from the intake hole 5 into the rotor chamber 31, the amount of oil sucked from the suction port 32 can be reduced by the amount of the outside air, so that the amount of oil discharged from the discharge port 33 can be reduced. .. Therefore, the oil discharge amount can be set to an appropriate amount so as not to be excessive at the time of high rotation of the engine where the oil discharge amount tends to be excessive. As a result, the oil pressure (discharge pressure) can be reduced, and unnecessary pumping work of the internal gear pump 1 can be reduced, so that the drive torque can be reduced. Therefore, since the mechanical efficiency can be increased, the efficiency of the internal gear pump 1 can be increased.

Specifically, as shown by the solid line in FIG. 3, the discharge pressure of the internal gear pump 1 according to the first embodiment increases in proportion to the increase in the pump rotation speed up to a predetermined pump rotation speed n. The horizontal axis of FIG. 3 indicates the pump rotation speed (the right side of the paper surface is “large”), and the vertical axis indicates the discharge pressure (the upper side of the paper surface is “large”). The inclination of the increase in discharge pressure with respect to the increase in the pump rotation speed in the inscribed gear pump 1 up to a predetermined pump rotation speed n is the same as that of the inscribed gear pumps A (broken line) and B (two-point chain line). .. The internal gear pump A includes a relief valve in addition to the same pump rotor, pump case, and chamber as the internal gear pump 1 according to the first embodiment. The internal gear pump B includes the same pump rotor, pump case, and chamber as the internal gear pump 1 according to the first embodiment. The internal gear pumps A and B do not include any of the intake hole, the outside air amount variable mechanism, the oil supply hole, and the oil circulation mechanism provided in the internal gear pump 1 according to the first embodiment.

Then, unlike the internal gear pumps A and B, the discharge pressure of the internal gear pump 1 after the predetermined pump rotation speed n is kept constant without increasing even if the pump rotation speed increases. As described above, it is preferable that the internal gear pump 1 according to the first embodiment can keep the discharge pressure constant after a predetermined rotation speed, but even if it is not constant, the internal gear pump A is provided with the intake hole 5. Is also included in the invention when the inclination is significantly small (the increase in discharge pressure can be reduced). On the other hand, as shown in FIG. 3, the discharge pressure of the inscribed gear pump A after the predetermined pump rotation speed n is increasing as the rotation speed is increased, although the inclination is gentle. .. The discharge pressure of the inscribed gear pump B after a predetermined pump rotation speed n increases linearly without changing the inclination. As described above, the internal gear pump 1 according to the first embodiment is an internal gear pump by sending outside air from the intake hole 5 into the rotor chamber 31 when the predetermined pump rotation speed n (discharge pressure) is reached. Compared with A and B, the amount of oil sucked from the suction port 32 can be reduced, and the amount of oil discharged from the discharge port 33 can be reduced.

As shown by the solid line in FIG. 4, the drive torque of the inscribed gear pump 1 up to a predetermined pump rotation speed n increases as the pump rotation speed increases. The horizontal axis of FIG. 4 is the same as the horizontal axis of FIG. 3, and indicates the pump rotation speed, and the vertical axis indicates the driving torque (“larger” toward the upper side of the paper). The amount of increase in the drive torque with respect to the amount of increase in the pump rotation speed up to a predetermined pump rotation speed n in the internal gear pump 1 is the same as that of the internal gear pumps A and B. The inscribed gear pump 1 can suppress an increase in drive torque after a predetermined pump rotation speed n. This is because the inscribed gear pump 1 can reduce unnecessary pumping work by reducing the amount of oil sucked from the suction port 32 after the predetermined pump rotation speed n. On the other hand, the inscribed gear pumps A and B have not been able to suppress an increase in drive torque after a predetermined pump rotation speed n.

The present invention is not limited to these examples, and is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Internal gear pump 2 Pump rotor 21 Inner rotor 21a External teeth 22 Outer rotor 22a Internal teeth 3 Pump case 31 Rotor chamber 31b Bottom surface 32 Suction port 32b Bottom surface 33 Discharge port 34 Shaft hole 4 Chamber 5 Intake hole 6 External air volume variable mechanism 7 Refueling hole 8 Oil circulation mechanism 81 Branch path 12 Suction path 13 Discharge path 14 Drive shaft

Claims (2)

A pump rotor having an inner rotor having outer teeth and an outer rotor having internal teeth meshing with the outer teeth and provided eccentrically with respect to the inner rotor.
A pump case having a rotor chamber for accommodating the pump rotor and a suction port and a discharge port opening in the rotor chamber.
A chamber formed between the outer teeth and the inner teeth and whose volume increases or decreases with the rotation of the inner rotor and the outer rotor to discharge oil sucked from the suction port from the discharge port.
An intake hole that opens into the intake port to send outside air,
An inscribed gear pump including an outside air amount variable mechanism that opens and closes the intake hole to change the amount of outside air taken in by using the oil pressure of the oil discharged from the discharge port. The internal gear pump according to claim 1, further comprising an oil supply hole that opens into the rotor chamber and supplies oil discharged from the discharge port between the bottom surface of the rotor chamber and the end surface of the pump rotor.

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