JP4600612B2 - Internal gear pump device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal gear-type pump device, and in particular, introduces hydraulic oil between the outer peripheral surface of a driven gear that forms an outer rotor and a casing that houses the driven gear, and at the bearing surface of the casing. The present invention relates to an internal gear type pump device that is provided with a pocket to enhance the lubrication function on the outer peripheral surface of the driven gear.
[0002]
[Prior art]
Generally, in the internal gear type pump device, since the hydraulic oil discharge pressure is not so high, the driven gear forming the outer rotor has a certain clearance between the casing and the outer peripheral surface of the driven gear. It is designed to be incorporated in a state having The driven gear outer peripheral portion is lubricated when a part of the hydraulic oil enters the gap.
[0003]
[Problems to be solved by the invention]
By the way, in recent internal gear type pump devices, those having a high discharge pressure specification have been adopted, in which case the driven gear on the discharge port side is in the volume chamber formed on the discharge side. It will be pressed against the casing by pressure. In such a state, if the driven gear rotates at a high speed, there is a possibility that an oil film breakage phenomenon occurs on the outer peripheral surface of the driven gear. In order to cope with such a problem, an oil reservoir is provided at a sliding portion of the casing with respect to the outer peripheral surface of the driven gear to thereby prevent oil film breakage (Japanese Utility Model Laid-Open No. 60-192295). Issue). Further, as described in Japanese Patent Application Laid-Open No. 9-14152, a narrow groove is provided in a portion of the casing (housing) in contact with the driven gear side surface portion, and is formed between the outer peripheral surface of the driven gear and the casing through the narrow groove. In some cases, hydraulic oil is introduced into the gaps to be lubricated, thereby lubricating the outer peripheral surface of the driven gear. However, these are intended to allow the pressure oil in the volume chamber (pump chamber) to enter the outer peripheral surface of the driven gear through a fine gap between the driven gear and the casing, thereby performing a lubricating action. is there. Therefore, in these pump apparatuses that handle high-pressure oil, oil leakage from the outer peripheral portion increases, and there is a problem that volume efficiency of the pump apparatus is lowered. In order to solve such problems, a pocket that is isolated from the side surface of the driven gear is provided near the discharge port and the suction port and in a casing that makes a relative sliding movement with the outer peripheral surface of the driven gear. It is an object (problem) of the present invention to provide an internal gear type pump device that is provided and thereby improves the lubrication function.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the following measures are taken in the present invention. That is, in the first aspect of the present invention, a drive gear that forms the drive side, a driven gear that includes an internal gear portion having a larger number of teeth than the drive gear, and a casing that houses the drive gear and the driven gear, In the internal gear type pump device comprising: a first pocket into which pressure oil from the discharge port is introduced in the vicinity of the discharge port of the casing and in contact with the outer peripheral portion of the driven gear. A second pocket into which hydraulic fluid is introduced from the suction port is provided in the vicinity of the suction port and in contact with the outer peripheral portion of the driven gear . Press the driven gear toward the center of rotation at the center in the circumferential direction of one pocket The driving force and the driving force received from the drive gear are extended in the direction of the combined force, and set closer to the front side in the rotational direction of the driven gear than the intersection with the outer peripheral surface of the driven gear. to, and circumferentially central portion angle sandwich the driven gear rotation center point of each other these two pockets, as a value of less than 180 ° in the rotational direction of the driven gear from the central portion of the first pocket, further The width of the pockets in the rotational axis direction of the driven gear is set to be smaller than the width of the driven gear in the rotational axis direction . By adopting such a configuration, in the present invention, the driven gear is pushed back toward the center of rotation by the action of the pressure oil introduced into the first pocket, and the outer peripheral surface of the driven gear on the second pocket side is It will be pressed more strongly on the casing bearing surface side. As a result, the hydraulic oil in the second pocket is more strongly subjected to the wedge effect and enters between the driven gear outer peripheral surface and the casing bearing surface. That is, the hydrodynamic bearing effect by the lubricating oil is exhibited.
[0005]
Furthermore, in the present invention, the width of the two pockets in the rotational axis direction of the driven gear is made smaller than the width of the driven gear in the rotational axis direction, and pressure oil is introduced into the first pocket. A configuration was adopted in which a restriction was provided in the flow path. By adopting such a configuration, in the present invention, the pressure oil or the like in the volume chamber (pump chamber) leaks into the pocket via a sliding surface between the driven gear and the casing. Can be suppressed, and the volumetric efficiency of the entire pump device can be improved.
[0006]
Next, the invention described in claim 2 will be described. The basic point of this is the same as that of the first aspect. That is, in the present invention, with respect to the internal gear pump according to claim 1, wherein, it was decided to adopt a configuration in which the provided the aperture in the channel for supplying hydraulic fluid to said second pocket. By adopting such a configuration, in the present invention, it is possible to prevent air bubbles from being mixed into the introduced hydraulic oil when the hydraulic oil is introduced into the second pocket. . As a result, the wedge effect brought about by the hydraulic oil introduced into the second pocket is more strongly exhibited.
[0008]
Next, an invention according to claim 3 will be described. The basic point of this is the same as that of the first or second aspect . That is, in the present invention, the internal gear type pump device according to claim 1 or claim 2 is configured such that a restriction is provided in a flow path for introducing pressure oil into the first pocket. . By adopting such a configuration, in the present invention, the oil leakage phenomenon from the volume chamber (pump chamber) can be suppressed, and the volume efficiency of the entire pump device can be improved. become.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, an internal gear pump device according to the present embodiment includes a drive gear 1 that forms a drive side, and a driven gear 2 that includes an internal gear portion having a larger number of teeth than the drive gear 1. A crescent-shaped partition plate provided so as to fill a gap formed between the casing 3 housing the drive gear 1 and the driven gear 2 and the gear portion 11 of the drive gear 1 and the gear portion 21 of the driven gear 2 4. A part of the casing 3 is provided with a suction port 33 for supplying hydraulic oil into a volume chamber (pump chamber) formed by the gear portions 11 and 21. Is provided with a discharge port 31 for discharging the pressure oil formed in the volume chamber (pump chamber). Further, a first pocket 5 into which pressure oil is introduced from the discharge port 31 is formed in the vicinity of the discharge port 31 of the casing 3 in contact with the outer peripheral portion of the driven gear 2. . In the vicinity of the suction port 33 of the casing 3, a second pocket 6 into which hydraulic oil is introduced from the suction port 33 is formed in contact with the outer peripheral portion of the driven gear 2. .
[0010]
In such a configuration, the pockets 5 and 6 have an angle (θ) sandwiching the rotational center point (O) of the driven gear 2 that is less than 180 ° in the rotational direction of the driven gear 2. It is set. That is, the relational expression of θ <180 ° is established. Specifically, as shown in FIG. 1, the second pocket 6 is pressed at the central point (P1) of the first pocket 5 toward the O direction which is the center of rotation of the driven gear 2. Of the driving force (vector Vr) and the driving force (vector Vt) received from the drive gear 1 in the combined force direction (vector V direction) and the intersection (P3 ) To the front side in the rotational direction of the driven gear 2. That is, the position of the second pocket 6 is operated so that the driven gear 2 is pushed back by the force received from the first pocket 5 with respect to the first pocket 5. In other words, the driven gear 2 is provided on the near side in the rotational direction. As a result, the lubricating function of the hydraulic oil introduced into the second pocket 6, in particular, the wedge effect function is exerted more strongly.
[0011]
A specific configuration of the pockets 5 and 6 having such a configuration will be described with reference to FIGS. First, as shown in FIGS. 2 and 3, the width (b) of the concave portions of the pockets 5 and 6 provided in contact with the outer peripheral surface of the driven gear 2 of the casing 3 in the rotational axis direction of the driven gear is as shown in FIGS. 2 has a value (narrow width) smaller than the width (B) in the rotation axis direction . The pockets 5 and 6 are provided with an introduction flow path 7 connected to the suction port 33 or the discharge port 31, as shown in FIGS. The diaphragm 35 itself is formed. In addition, the introduction flow path 7 composed of such a small pore also serving as the throttle 35 may be provided on both side surfaces of the pockets 5 and 6 in the driven gear rotating shaft direction as shown in FIGS. However, it may be provided on either one side.
[0012]
As shown in FIG. 3, the structure around the driven gear 2 housing portion of the casing 3 in which the pockets 5 and 6 having such a configuration are provided has a small roundness at the place where the shoulder portion 23 of the driven gear 2 abuts (the corner portion 32). Is provided. In order to prevent the roundness in the corner portion 32 from causing interference when the driven gear 2 is assembled, chamfering is generally performed at the shoulder portion 23 of the driven gear 2. Accordingly, since a fine gap is formed over the entire circumference of the driven gear 2 between the shoulder 23 of the driven gear 2 and the corner 32 of the casing 3 in such a state, the pockets 5 and 6 are If it is provided over the entire width of the driven gear 2 in the rotation axis direction, the high pressure oil from the discharge side pocket (first pocket) 5 leaks into the suction side pocket (second pocket) 6 through the fine gap (intrusion). There is a risk. As a result, the volumetric efficiency may be reduced. To address this problem, the width of the pockets 5 and 6 in the rotation axis direction of the driven gear (b) is necessary to the value smaller than the width of the driven gear 2 (B) in the rotation axis direction There is. From this point of view, in the present embodiment, the width (b, B) between the two is set so that the relational expression b <B is satisfied.
[0013]
Another embodiment (modified example) of the configuration around the pockets 5 and 6 will be described with reference to FIGS. 5 and 6. In this case, the pockets 5 and 6 are formed by a casting means at the same time when the casing 3 is cast. Therefore, both pockets 5 and 6 are provided in a state of being shifted to one side end portion side of the casing 3, for example, the side in contact with the cover 9. Specifically, as shown in FIG. 5, the second pocket 6 that is a suction port is formed so as to contact the cover 9 side, that is, to have an opening at the time of casting on the cover 9 side, The introduction flow path 7 connected to the suction port 33 is provided continuously to the second pocket 6 formed in this way. A restrictor 35 having a narrow passage is formed at the connection portion between the introduction flow path 7 and the suction port 33 provided on the cover 9 side. By providing such a restriction 35, the mixing of bubbles into the pocket 6 on the suction side is suppressed. Even in such a configuration, the relational expression b <B is established as shown in FIG.
[0014]
Further, as shown in FIG. 6, the first pocket 5 which is a discharge side pocket is formed so as to have an opening at the time of casting on the cover 9 side. The first pocket 5 is connected to the introduction flow path 7 connected to the discharge port 31, and is provided on the cover 9 side as shown in FIG. is there. In this case, it may be considered that the introduction flow path 7 is composed of pores in some cases to increase the volume efficiency of the entire pump device. In the structure having such a configuration, the width (b) of the first pocket 5 in the rotational axis direction of the driven gear is such that the relational expression b <B is satisfied as shown in FIG. It is set.
[0015]
Next, the operation and the like of this embodiment configured as described above will be described. That is, in the present embodiment, when the drive gear 1 starts rotating and the pump device starts operating, the discharge side pocket 5 as the first pocket has a discharge side as shown in FIG. Discharged oil is introduced from the port 31 through the introduction flow path 7 (35). At the same time, hydraulic oil is also introduced into the suction side pocket 6 which is the second pocket from the suction port 33 side via the introduction flow path 7 also serving as the throttle 35 (see FIGS. 2 to 5). Therefore, in the present embodiment, as shown in FIG. 1, the pressure oil introduced into the first pocket 5 acts, and the driven gear 2 is pushed back in the O direction which is the rotation center point. On the second pocket 6 side, the outer peripheral surface of the driven gear 2 is more strongly pressed against the bearing surface side of the casing 3. As a result, the hydraulic oil in the second pocket 6 receives a stronger wedge effect and enters between the outer peripheral surface of the driven gear 2 and the bearing surface of the casing 3. Bearing effect will be received.
[0016]
In particular, in the present embodiment, the position of the second pocket 6 is pressed against the driven gear 2 toward the center of rotation (O) at the center (point P1) of the first pocket 5. On the extension line of the combined force (vector V) of the acting force (vector Vr) and the driving force (vector Vt) received from the drive gear 1, and the intersection with the outer peripheral surface of the driven gear 2 Since the configuration in which the driven gear 2 is set to the front side in the rotational direction of the driven gear 2 rather than (P3) is adopted, the hydraulic oil in the second pocket 6 receives the wedge effect more strongly by the action of the vector V. As a result, the function of the hydraulic oil stored in the pocket 6 as a lubricating oil is further enhanced.
[0017]
In addition, by the action of the throttle 35 provided in the middle of the introduction flow path 7 of the hydraulic oil to the second pocket 6 that is the suction side pocket, or by using the introduction flow path 7 together with the restriction 35 made of pores, Air bubbles are prevented from being mixed into the second pocket 6, thereby preventing the occurrence of cavitation and making it possible to further exhibit the wedge effect due to the hydraulic oil (lubricating oil). Also, the width of each pocket 5 and 6 in the rotation axis direction of the driven gear and (b), by setting to be a smaller value than the width of the driven gear 2 in the direction of the axis of rotation (B), both pockets 5,6 It is possible to suppress the surrounding oil leakage phenomenon, thereby improving the volumetric efficiency of the entire pump device.
[0018]
【The invention's effect】
According to the present invention, the drive gear that forms the drive side, the driven gear that includes the internal gear portion having a larger number of teeth than the drive gear, and the casing that accommodates the drive gear and the driven gear. With respect to the gear type pump device, a first pocket into which pressure oil is introduced from the discharge port is provided in the vicinity of the discharge port of the casing and in contact with the outer peripheral portion of the driven gear, and in the vicinity of the suction port of the casing. A second pocket into which hydraulic oil is introduced from the suction port is provided at a position in contact with the outer peripheral portion of the driven gear, and an angle between the driven gear rotation center points of both pockets is 180 in the rotation direction of the driven gear. Since it was decided to adopt a configuration with a value less than °°, the first pocket The driven gear become be pushed back to its center of rotation by the action of the introduced pressurized oil, the driven gear peripheral surface in the second pocket side became strongly pressed by a casing bearing surface side. As a result, the hydraulic oil in the second pocket is more strongly subjected to the wedge effect and enters between the outer peripheral surface of the driven gear and the casing bearing surface, so that the bearing effect by the hydraulic oil (lubricating oil) is more exerted. Became.
[0019]
Further, a vector obtained by combining the position of the second pocket with a vector that acts to press the driven gear toward the center of rotation of the driven pocket at the center of the first pocket and a vector related to the driving force received from the drive gear. In the present invention, the operation in the second pocket is carried out by setting the front side in the direction of rotation of the driven gear relative to the intersection with the outer peripheral surface of the driven gear. The wedge effect of oil can be exerted more strongly, and the dynamic pressure bearing effect by lubricating oil can be exerted strongly.
[0020]
Further, by providing a throttle in the flow path for introducing the hydraulic oil into the second pocket (in the introduction flow path), in the present invention, the hydraulic oil is introduced into the second pocket. In addition, air bubbles can be prevented from being mixed into the introduced hydraulic oil, and cavitation can be prevented from occurring. As a result, the wedge effect brought about by the hydraulic oil introduced into the second pocket can be exerted more strongly. Further, of both pockets provided in the casing, by the width in the rotation axis direction of the driven gear and (b), to limit to have a value smaller than the width of the driven gear (B) in the rotation axis direction, the volume It has become possible to prevent pressure oil or the like in the chamber (pump chamber) from leaking into the pocket via a sliding surface between the driven gear and the casing. As a result, the volumetric efficiency in the present pump device can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the overall configuration of the present invention.
FIG. 2 is a plan view showing a configuration around a pocket portion according to the present invention.
FIG. 3 is a cross-sectional view showing a structure around a pocket portion according to the present invention.
FIG. 4 is a longitudinal sectional view showing a structure around a pocket portion according to the present invention.
FIG. 5 is a view showing a modification of the suction side pocket (second pocket) according to the present invention.
FIG. 6 is a view showing a modification of the discharge side pocket (first pocket) according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drive gear 11 Gear part 2 Driven gear 21 Gear part 23 Shoulder part 3 Casing 31 Discharge port 32 Corner part 33 Suction port 35 Diaphragm 4 Partition plate 5 First pocket (discharge side pocket)
6 Second pocket (suction side pocket)
7 Channel (Introduction channel)
9 Cover

Claims (3)

In an internal gear type pump device comprising a drive gear that forms a drive side, a driven gear that includes an internal gear portion having a larger number of teeth than the drive gear, and a casing that houses the drive gear and the driven gear, A first pocket into which pressure oil is introduced from the discharge port is provided in the vicinity of the discharge port of the casing and in contact with the outer peripheral portion of the driven gear, and in the vicinity of the suction port of the casing and in the vicinity of the driven gear. A second pocket into which hydraulic oil from the suction port is introduced is provided at a position in contact with the outer peripheral portion, and the entire circumferential area of the second pocket is arranged at the central portion in the circumferential direction of the first pocket. From the drive gear and the force that acts to press toward the center of rotation A on the extension of the direction of power and, combined force, than the intersection between the driven gear outer peripheral surface so as to set the front side in the rotational direction of the driven gear, and the circumferential direction of both pockets The angle between the central portions of the driven gear rotation center point is set to a value less than 180 ° in the rotational direction of the driven gear from the central portion of the first pocket, and both the pockets in the rotational axis direction of the driven gear. The internal gear type pump device characterized in that the width of the internal gear is made smaller than the width of the driven gear in the direction of the rotation axis . 2. The internal gear pump device according to claim 1 , wherein a throttle is provided in a flow path for supplying hydraulic oil to the second pocket . 3. The internal gear pump device according to claim 1, wherein a throttle is provided in a flow path for introducing pressure oil into the first pocket.

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