Patent Application
20240280098
The present invention relates to an internal gear pump and an internal gear motor.
As a hydraulic source for industrial vehicles, construction machines, agricultural machines, and the like, an internal gear pump including a set of internal gear and external gear that mesh with each other in a casing, and a crescent (also referred to as a filler piece) that divides a liquid feeding space formed between those gears into a high pressure region and a low pressure region is used. As such an internal gear pump, in Patent Literature 1, one pressure introduction groove is provided in a cover that is a sealing member attached to side surfaces of both gears, so that an enclosed space formed between a crescent and tooth grooves of the gears communicates with the high pressure region. In the internal gear pump in which such a pressure introduction groove is formed, oil is introduced into the tooth grooves from the high pressure region through the pressure introduction groove, whereby a pressure of the oil accumulated in the tooth grooves is gradually increased as the gears rotate. As a result, vibration of side plates and noise of the pump due to rapid increase in the pressure of the oil accumulated in the tooth grooves with the rotation are reduced.
However, for example, in an internal gear pump including one pressure introduction groove having a monotonous shape such as a linear shape, when a rotation speed of the pump is changed from low rotation to high rotation, a pressure balance in the liquid feeding space is lost, and performance and durability of the pump may be deteriorated.
As a result of intensive studies on such a problem, the present inventors have found that the conventional internal gear pump including one pressure introduction groove having a monotonous shape has a characteristic that timing of pressure rise in the tooth grooves due to the rotation is delayed in a case where the gears rotate at a high speed as compared with a case where the gears rotate at a low speed. The present inventors have further extensively conducted studies, and have found that, in the conventional internal gear pump, since there is a large difference in the timing of the pressure rise in the tooth grooves at the time of high rotation and low rotation, there is a large difference in a ratio (area) of the high pressure region in the liquid feeding space between the case of high rotation and the case of low rotation, and therefore when the rotation speed of the pump is changed, for example, from low rotation to high rotation, the ratio of the high pressure region in the liquid feeding space is greatly changed, so that the pressure balance is lost, and the performance and durability of the pump may be deteriorated. This can also be applied to an internal gear motor having a configuration similar to such a phenomenon.
Therefore, a main objective of the present invention is to reduce a difference in timing of a pressure change in tooth grooves between low rotation and high rotation in an internal gear pump and an internal gear motor.
A first aspect of the present invention relates to an internal gear pump including: an internal gear rotatably fitted in a body: an external gear inscribed in and meshed with the internal gear: a filler piece that partitions a liquid feeding space formed between the internal gear and the external gear into a high pressure region and a low pressure region; and a sealing member that covers both end surfaces of both the gears in a rotation axis direction and seals the liquid feeding space, in which a communication groove for communicating an enclosed space surrounded by the filler piece and a tooth groove of at least one of the gears with the high pressure region is formed, and the communication groove is formed such that a cross-sectional area communicating with the enclosed space continuously increases and an increase rate thereof acceleratively increases as a rotation phase of both the gears advances.
Also, a second aspect of the present invention relates to an internal gear motor including: an internal gear rotatably fitted in a body: an external gear inscribed in and meshed with the internal gear: a filler piece that partitions a liquid feeding space formed between the internal gear and the external gear into a high pressure region and a low pressure region; and a sealing member that covers both end surfaces of both the gears in a rotation axis direction and seals the liquid feeding space, in which a communication groove for communicating an enclosed space surrounded by the filler piece and a tooth groove of at least one of the gears with the low pressure region is formed, and the communication groove is formed such that a cross-sectional area communicating with the enclosed space continuously increases and an increase rate thereof acceleratively increases as a rotation phase of both the gears advances.
According to the aspect of the present invention configured as described above, since the communication groove is formed such that the cross-sectional area communicating with the enclosed space continuously increases as the rotation phase of both the gears advances, and the increase rate acceleratively increases, the amount of a hydraulic fluid (oil or the like) introduced from the communication groove into the tooth groove of the gear can be acceleratively increased with the rotation. Therefore, as compared with the conventional one in which only one monotonically shaped communication groove is formed, only the timing of the pressure change in the tooth groove at the time of high rotation can be significantly advanced without significantly advancing the timing of the pressure change in the tooth groove at the time of low rotation of both the gears. As a result, in the internal gear pump and the internal gear motor, the difference of the timing of the pressure change in the tooth groove between the time of low rotation and the time of high rotation is reduce to enable an improvement in the performance and durability of the pump.
Hereinafter, an internal gear pump 100 according to a first embodiment of the present invention will be described with reference to the drawings.
An internal gear pump 100 according to the present embodiment is used as a hydraulic source of, for example, an industrial vehicle, a construction machine, an agricultural machine, or the like, and is configured to suck and discharge a fluid (oil such as mineral oil. Also, referred to as operating fluid) by rotating a set of internal gear 2 and external gear 3 housed in a body 1. Specifically, as illustrated in
The body 1 has a substantially cylindrical shape having a hollow body shape. As illustrated in
The internal gear 2 has a ring shape including a plurality of inward teeth 22 along a radial direction, and is a so-called internal gear. The internal gear 2 is rotatably fitted and accommodated in the body 1 such that its rotation axis is parallel to the axial direction of the body 1.
The external gear 3 includes a plurality of outward teeth 32 along the radial direction, and is a so-called pinion gear. The external gear 3 has a reference circle diameter smaller than a reference circle diameter of the internal gear 2 and the number of teeth smaller than the number of teeth of the internal gear 2. The external gear 3 is provided to be inscribed and meshed with the internal gear 2 such that its rotation axis is parallel to the rotation axis of the internal gear 2. As illustrated in
The filler piece 4 is provided between the internal gear 2 and the external gear 3 in the body 1, and partitions the liquid feeding space into a high pressure region RH and a low pressure region RL. Specifically, the filler piece 4 has a crescent shape integrally projected on the front cover 7, and includes an outer peripheral surface 41 in contact with tooth tips of the internal gear 2 and an inner peripheral surface 42 in contact with tooth tips of the external gear 3. The outer peripheral surface 41 has the same circle diameter as a tooth tip circle diameter of the internal gear 2, and simultaneously contacts a plurality of tooth tips of the internal gear 2 to seal oil accumulated in tooth grooves 21. The inner peripheral surface 42 has the same circle diameter as a tooth tip circle diameter of the external gear 3, and simultaneously contacts a plurality of tooth tips of the external gear 3 to seal oil accumulated in tooth grooves 31. As illustrated in
The sealing member 5 of the present embodiment is inserted between the body 1 and both the gears 2 and 3 so as to cover both end surfaces of the internal gear 2 and the external gear 3, and seals the liquid feeding space. Specifically, the sealing member 5 (also referred to as a side plate) is a plate-like member having a constant thickness, and is fitted to an inner periphery of the body 1 so as to be slidable in the axial direction.
The sealing member 5 is provided with a communication port 51 that allows the high pressure region RH to communicate with a space between the sealing member 5 and the front cover 7 (or the rear cover 8). The communication port 51 is formed by a through hole penetrating the sealing member 5 in a plate thickness direction, and is opened on both side surfaces of the sealing member 5. The sealing member 5 is provided with a plurality of (specifically, two) the communication ports 51, and each of the communication ports 51 is provided at a position where the teeth 22 of the rotating internal gear 2 and the teeth 32 of the external gear 3 pass thereover in the high pressure region RH when viewed from the rotation axis direction.
In the sealing member 5, communication grooves 6 for communicating the high pressure region RH and the enclosed space T are formed. The communication grooves 6 are intended to gradually increase a pressure in the enclosed space T by introducing oil from the high pressure region RH into the enclosed space T having a relatively low pressure.
In the internal gear pump 100 configured as described above, the external gear 3 and the internal gear 2 are rotationally driven by the drive shaft 9 to enable the oil sucked from the inlet Pi to be discharged from the outlet Po. Specifically, when the external gear 3 and the internal gear 2 meshing with the external gear 3 are rotated, oil as a hydraulic fluid is introduced from the inlet Pi to the low pressure region RL, and the oil is enclosed in the enclosed space T, carried to the high pressure region RH, and discharged from the outlet Po.
Thus, in the internal gear pump 100 of the present embodiment, the communication grooves 6 are formed such that the cross-sectional area communicating with the enclosed space T continuously increases as the rotation phase of both the gears 2 and 3 advances, and its increase rate acceleratively increases. Specifically, in the internal gear pump 100 of the present embodiment, a plurality of communication grooves 6 for communicating the enclosed space T and the high pressure region RH are formed, and the respective communication grooves 6 are formed so that the high pressure region RH and the enclosed space T communicate with each other at different timings as the internal gear 2 and the external gear 3 rotate.
More specifically, as shown in
The plurality of inner communication grooves 6i and the plurality of outer communication grooves 6o are formed in the same number (three in this case) in the sealing member 5. The communication grooves 6i and 6o are formed such that the timing at which the inner enclosed space Ti comes on each of the inner communication grooves 6i matches with the timing at which the outer enclosed space To comes on each of the outer communication grooves 6o as the gears 2 and 3 rotate.
Specifically, each of the communication grooves 6 has a needle shape formed along the side surface of the sealing member 5. More specifically, each communication groove 6 is formed such that a base end thereof is connected to the communication port 51 in the high pressure region RH and a tip thereof is directed straight toward the enclosed space T. Here, each of the communication grooves 6 has a tapered shape toward the tip.
The communication grooves 6 communicating with the common enclosed space T are arranged at substantially equal intervals away from a central axis of the body 1. Further, the communication grooves 6 are formed so as to be substantially parallel to each other from the communication port 51 toward the enclosed space T. A depth, width, and length of each of the communication grooves 6 may be different from each other or may be the same. Here, the length of each communication groove 6 is set to be shorter as it is farther from the central axis of the body 1.
The plurality of communication grooves 6 are formed so as to cross the teeth 22 and 32 that partition the high pressure region RH and the enclosed space T, and allow the high pressure region RH and the enclosed space T adjacent thereto to communicate with each other. Specifically, each inner communication groove 6i is formed so as to cross the teeth 32 of the external gear 3 that partitions the high pressure region RH and the inner enclosed space Ti. Each of the outer communication grooves 6o is formed so as to cross the teeth 22 of the internal gear 2 that partitions the high pressure region RH and the outer enclosed space To.
The positions of the tips of these communication grooves 6 are set such that a timing at which the tooth grooves 21 and 31 come on the respective communication grooves 6 is different from each other as the gears 2 and 3 rotate. Specifically, the plurality of communication grooves 6 communicating with the common enclosed space T are formed such that the tooth surfaces 2b and 3b on a front side in a rotational direction configuring the tooth grooves 21 and 31 of the gears 2 and 3 have different rotation phases reaching the tips of the respective communication grooves 6. For example, as illustrated in
With the formation of each communication groove 6 as described above, as illustrated in
The “cross-sectional area of the communication grooves 6 communicating with the enclosed space T” means flow passage cross-sectional areas of the communication grooves 6 at the positions of the tooth surfaces 2a and 3a of the teeth 22 and 32 on the front side in the rotational direction in a state where the communication grooves 6 communicates with the enclosed space T, that is, in a state where the communication grooves 6 cross the teeth 22 and 32 partitioning the high pressure region RH and the enclosed space T.
According to the internal gear pump 100 of the present embodiment configured as described above, since the plurality of communication grooves 6 are formed so that the high pressure region RH and the enclosed space T communicate with each other at different timings as the gears 2 and 3 rotate, and the total cross-sectional area of the communication grooves 6 communicating with the enclosed space T increases each time the tooth grooves 21 and 31 of the gears 2 and 3 come on the communication grooves 6 while the rotation phase advances. As a result, as the rotation phase of both the gears 2 and 3 advances, the total cross-sectional area of the plurality of communication grooves 6 communicating with the enclosed space T continuously increases, and the increase rate acceleratively increases. Therefore, the amount of hydraulic fluid (oil or the like) introduced from each of the communication grooves 6 into the tooth grooves 21 and 31 of the gears 2 and 3 can be acceleratively increased with rotation. Therefore, as compared with the conventional one having one monotonically shaped communication groove (for example, a linear communication groove in which the cross-sectional area does not change as the rotation phase of the gear advances, a communication groove in which the cross-sectional area monotonously increases as the rotation phase of the gear advances, or the like), only timing of a pressure rise in the tooth grooves 21 and 31 at the time of high rotation can be significantly advanced without significantly advancing the timing of the pressure rise in the tooth grooves 21 and 31 at the time of low rotation of both the gears 2 and 3. As a result, as illustrated in
Here, even in a case where there are a plurality of communication grooves for communicating the enclosed space T and the high pressure region RH, for example, as illustrated in
Next, an internal gear pump 100 according to a second embodiment of the present invention will be described with reference to the drawings. As illustrated in
In the internal gear pump 100 of the second embodiment, as in the first embodiment, the communication grooves 6 are formed such that a cross-sectional area communicating with an enclosed space T continuously increases as a rotation phase of both gears 2 and 3 advances, and its increase rate acceleratively increases.
Specifically, as shown in
Specifically, the communication grooves 6 have a needle shape formed along the side surface of the sealing member 5. More specifically, the communication groove 6 is formed such that a base end thereof is connected to the communication port 51 in the high pressure region RH and a tip thereof is tapered toward the enclosed space T.
In the internal gear pump 100 of the second embodiment, as illustrated in
According to the internal gear pump 100 of the second embodiment configured as described above, the communication grooves 6 has a triangular pyramid shape that tapers from the high pressure region RH toward the enclosed space T, and all of the plurality of sides 61 have a curved shape that widens outward from the tip side toward the base end side. Therefore, as illustrated in
In addition, in the internal gear pump 100 of the second embodiment, the communication grooves 6 have a pyramidal shape that widens from the tip side toward the base end side, so that the increase rate in the flow path cross-sectional area of the communication grooves 6 accompanying the rotation of the gears 2 and 3 can be acceleratively increased without forming a plurality of communication grooves. Therefore, even in a case where it is difficult to form the plurality of communication grooves 6 in a limited machining area, one communication groove 6 is formed, so that an effect of significantly advancing only the timing of the pressure increase in the tooth grooves 21 and 31 at the time of high rotation can be achieved without significantly advancing the timing of the pressure increase in the tooth grooves 21 and 31 at the time of low rotation of the gears 2 and 3.
Note that the internal gear pump 100 of the present invention is not limited to the above embodiments.
For example, in the internal gear pump 100 of each of the above embodiments, the one or more communication grooves 6 are formed in the sealing member 5, but the present invention is not limited thereto. In another embodiment, one or more communication grooves 6 may be formed in a peripheral surface of a filler piece 4 which comes into contact with cutting edges of the gears 2 and 3 to seal the tooth grooves 21 and 31. For example, as shown in
In addition, the sealing member 5 of each of the above embodiments is configured by the side plate inserted between the body 1 and both the gears 2 and 3, but is not limited thereto. The internal gear pump 100 of another embodiment may not include the side plate, and the function as the sealing member 5 may be exerted by the front cover 7 and the rear cover 8. In this case, one or more communication grooves 6 may be formed on the side surface of the front cover 7 or the rear cover 8 facing the liquid feeding space.
In another embodiment, the base end of the communication grooves 6 may not be connected to the communication port 51 as long as the high pressure region RH and the enclosed space T can communicate with each other. The communication port 51 may not be provided at a position through which the teeth 22 and 32 of the rotating gears 2 and 3 pass.
In the first embodiment, the plurality of communication grooves 6 communicating with the common enclosed space T are formed so as to be substantially parallel to each other, but the present invention is not limited thereto. In addition, each of the communication grooves 6 of the first embodiment may have, for example, a rectangular shape instead of a tapered shape. Each of the communication grooves 6 may be linear or curved.
In the first embodiment, the plurality of outer communication grooves 6o and the same number of inner communication grooves 6i are formed, but the present invention is not limited thereto. In another embodiment, only one communication grooves 6 of the outer communication grooves 6o and the inner communication grooves 6i may be formed in plurality, and the other communication grooves may be one or zero. One of the plurality of outer communication grooves 6o and the plurality of inner communication grooves 6i may be formed so that the high pressure region RH and the enclosed space T communicate with each other at different timings as the gears 2 and 3 rotate, and the other may be formed so that the high pressure region RH and the enclosed space T communicate with each other at the same timing as the gears 2 and 3 rotate. In addition, these communication grooves 6 may not be formed such that the timing at which the inner enclosed space Ti comes on each of the inner communication grooves 6i matches with the timing at which the outer enclosed space To comes on each of the outer communication grooves 6o as the gears 2 and 3 rotate. It is preferable that the communication grooves 6 are formed such that the timings at which the pressures in the tooth grooves 21 and 31 increase are substantially the same as each other at the time of high rotation and/or low rotation of both the gears 2 and 3.
The communication grooves 6 of the internal gear pump 100 according to another embodiment may be a combination of a part or all of the aspect of the communication grooves 6 in the first embodiment and a part or all of the aspect of the communication grooves 6 in the second embodiment. For example, in the internal gear pump 100 of another embodiment, a plurality of communication grooves 6 are formed so that the high pressure region RH and the enclosed space T communicate with each other at different timings with the rotation of both the gears 2 and 3. A part or all of the plurality of communication grooves 6 may have a pyramid shape tapered from the high pressure region RH toward the enclosed space T, and at least one side of the pyramid shape may have a curved shape widening outward from the tip side toward the base end side.
The internal gear pump 100 of each embodiment described above can also function as an internal gear motor 100 in other embodiments. For example, a hydraulic fluid is introduced into a liquid feeding space from an inlet Pi and discharging the hydraulic fluid from the outlet Po, to enable rotational torque to be applied to the drive shaft 9 connected to the rotation shaft of the external gear 3. When functioning as the internal gear motor 100, in the liquid feeding space, a region communicating with the inlet Pi is the high pressure region RH, and a region communicating with the outlet Po is the low pressure region RL. That is, in the case of functioning as the internal gear motor 100, the communication grooves 6 are formed so as to communicate the enclosed space T with the low pressure region RL, and the communication grooves 6 is formed so that a cross-sectional area of the communication grooves 6 communicating with the enclosed space T continuously increases as the rotation phase of both the gears 2 and 3 advances, and the increase rate thereof acceleratively increases. In this case, the communication grooves 6 may have a pyramid shape tapered from the high pressure region RH toward the enclosed space T, and at least one side 61 thereof may have a curved shape widening outward from the tip side toward the base end side. Further, the plurality of communication grooves 6 are formed so as to communicate the enclosed space T with the low pressure region RL, and the respective communication grooves 6 are formed so that the low pressure region RL and the enclosed space T communicate with each other at different timings as the internal gear 2 and the external gear 3 rotate.
It is understood by those skilled in the art that the plurality of exemplary embodiments described above are specific examples of the following aspects.
(Section 1) An internal gear pump according to one aspect may include: an internal gear rotatably fitted in a body: an external gear inscribed in and meshed with the internal gear: a filler piece that partitions a liquid feeding space formed between the internal gear and the external gear into a high pressure region and a low pressure region; and a sealing member that covers both end surfaces of both the gears in a rotation axis direction and seals the liquid feeding space, in which a communication groove for communicating an enclosed space surrounded by the filler piece and a tooth groove of at least one of the gears with the high pressure region is formed, and the communication groove is formed such that a cross-sectional area communicating with the enclosed space continuously increases and an increase rate thereof acceleratively increases as a rotation phase of both the gears advances.
According to the internal gear pump according to a section 1, since the communication groove is formed such that the cross-sectional area communicating with the enclosed space continuously increases as the rotation phase of both the gears advances, and the increase rate acceleratively increases, the amount of a hydraulic fluid (oil or the like) introduced from the communication groove into the tooth groove of the gear can be acceleratively increased with the rotation. Therefore, only the timing of the pressure change in the tooth groove at the time of high rotation can be significantly advanced without significantly advancing the timing of the pressure change in the tooth groove at the time of low rotation of both the gears. As a result, in the internal gear pump, the difference of the timing of the pressure change in the tooth groove between the time of low rotation and the time of high rotation is reduce to enable an improvement in the performance and durability of the pump. The “cross-sectional area of the communication grooves” is a flow path cross-sectional area of one communication groove in a case where there is one communication groove communicating with the enclosed space, and is a total flow path cross-sectional areas of a plurality of communication grooves in a case where a plurality of communication grooves communicating with the common enclosed space are formed.
(Section 2) As a specific aspect of the internal gear pump according to the section 1, the communication groove has a pyramid shape tapered from the high pressure region toward the enclosed space, and at least one side of the pyramid shape has a curved shape widening outward from the tip side toward the base end side.
According to the internal gear pump according to a section 2, since the communication groove has a pyramidal shape in which sides spread in a curved shape from a tip toward a base end, a cross-sectional area of the communication groove communicating with the enclosed space can be continuously increased as the rotation phase of both the gears advances, and the increase rate thereof can be acceleratively increased.
In addition, according to the internal gear pump according to the section 2, the increase rate of the cross-sectional area of the communication grooves can be acceleratively increased with the rotation even in the case of one communication groove without forming the plurality of communication grooves. Therefore, even in a case where it is difficult to form the plurality of communication grooves in a limited processing region, the effect of the internal gear pump according to the section 1 can be achieved by one communication groove.
(Section 3) As a specific aspect of the internal gear pump according to the section 2, the communication groove has a triangular pyramid shape tapered from the high pressure region toward the enclosed space, and three sides of the shape have a curved shape widening outward from the tip side toward the base end side.
According to the internal gear pump according to a section 3, the effect of the internal gear pump according to the section 2 can be more remarkably exhibited.
(Section 4) In the internal gear pump according to any one of the sections 1 to 3, a plurality of the communication grooves may be formed, and the plurality of communication grooves may be formed so that the high pressure region and the enclosed space communicate with each other at different timings as both the gears rotate.
According to the internal gear pump according to a section 4, since the plurality of communication grooves are formed so that the high pressure region and the enclosed space communicate with each other at different timings as both the gears rotate, the total cross-sectional area of the respective communication grooves communicating with the enclosed space T increases each time the gear teeth grooves come on the respective communication grooves as the rotation phase advances, and the amount of hydraulic fluid (oil or the like) introduced from the respective communication grooves into the gear teeth grooves can be more acceleratively increased with the rotation. Therefore, the timing of the pressure rise in the tooth grooves at the time of high rotation can be further advanced without greatly changing the timing of the pressure rise in the tooth grooves at the time of low rotation of both the gears. As a result, in the internal gear pump, the deviation in the timing of the pressure rise in the tooth grooves between the low rotation time and the high rotation time can be further reduced.
(Section 5) As a specific aspect of the internal gear pump according to the section 4, in a relationship between the rotation phases of both the gears and the total cross-sectional area of the respective communication grooves communicating with the enclosed space, there is a bending point at which the total cross-sectional area continuously increases as the rotation phase advances and an increase rate of the total cross-sectional area changes stepwise as the rotation phase advances.
(Section 6) In the internal gear pump according to the section 4 or 5, the plurality of communication grooves may include a plurality of outer communication grooves communicating an outer enclosed space surrounded by a filler piece and the tooth grooves of the internal gears with the high pressure region, and a plurality of inner communication grooves communicating an inner enclosed space surrounded by the filler piece and the tooth grooves of the external gear with the high pressure region, each of the outer communication grooves may be formed so that the high pressure region and the outer enclosed space communicate with each other at different timings as both the gears rotate, and each of the inner communication grooves may be formed so that the high pressure region and the inner enclosed space communicate with each other at different timings as both the gears rotate.
According to the internal gear pump according to a section 6, a deviation in the timing of the pressure rise in the tooth grooves of both the internal gear and the external gear at the time of low rotation and high rotation can be reduced.
(Section 7) In the internal gear pump according to the section 6, the number of the plurality of inner communication grooves and the number of the plurality of outer communication grooves may be the same, and the plurality of inner communication grooves and the plurality of outer communication grooves may be formed such that a timing at which the inner enclosed space comes on each of the inner communication grooves and a timing at which the outer enclosed space comes on each of the outer communication grooves match with each other as the gears rotate.
According to the internal gear pump according to a section 7, a difference in the timing of the pressure increase accompanying the rotation in each tooth groove of the internal gear and the external gear can be reduced.
(Section 8) In the internal gear pump according to any one of the sections 4 to 7, each of the plurality of communication grooves may have a shape tapered from the high pressure region toward the enclosed space.
According to the internal gear pump according to a section 8, the pressure in the enclosed space can be gently increased with the rotation, and the pressure can be smoothly introduced from the high pressure region into the enclosed space.
(Section 9) In the internal gear pump according to any one of the sections 1 to 8, the communication grooves may be formed in the sealing member.
The above-described communication grooves can be formed in both the sealing member and the filler piece, for example. This filler piece is often made of a material such as brass having excellent workability, and therefore when the communication grooves are formed in the filler piece, there is a risk that the communication grooves may be scraped by a pressure of the hydraulic fluid. According to the internal gear pump according to a section 9, since the communication grooves are formed in the sealing member made of a material having abrasion resistance superior to that of the filler piece, breakage of the communication grooves due to the pressure of the hydraulic fluid can be suppressed.
(Section 10) As a specific aspect of the internal gear pump according to any one of the sections 1 to 9, the communication grooves are formed to communicate the high pressure region with the enclosed space adjacent to the high pressure region.
(Section 11) As a specific aspect of the internal gear pump according to any one of the sections 1 to 10, the communication grooves are formed so as to cross a tooth that partitions the high pressure region and the enclosed space.
(Section 12) An internal gear motor according to another aspect may include: an internal gear rotatably fitted in a body: an external gear inscribed in and meshed with the internal gear: a filler piece that partitions a liquid feeding space formed between the internal gear and the external gear into a high pressure region and a low pressure region; and a sealing member that covers both end surfaces of both the gears in a rotation axis direction and seals the liquid feeding space, in which a communication groove for communicating an enclosed space surrounded by the filler piece and a tooth groove of at least one of the gears with the low pressure region is formed, and the communication groove is formed such that a cross-sectional area communicating with the enclosed space continuously increases and an increase rate thereof acceleratively increases as a rotation phase of both the gears advances.
According to the internal gear motor according to a section 12, since the communication grooves are formed such that the cross-sectional area communicating with the enclosed space continuously increases and the increase rate acceleratively increases as the rotation phase of both the gears advances, the amount of hydraulic fluid (oil or the like) led out from the tooth grooves of the gears to the low pressure region through the communication grooves can be acceleratively increased with the rotation. Therefore, the timing of the pressure decrease in the tooth grooves at the time of high rotation can be significantly advanced without significantly changing the timing of the pressure decrease in the tooth grooves at the time of low rotation of both the gears. As a result, in the internal gear motor, the difference in the timing of the pressure drop in the tooth groove between the low rotation and the high rotation can be reduced.
In addition, the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.
According to the internal gear pump or the internal gear motor of the present invention described above, the difference in the timing of the pressure change in the tooth groove between the time of low rotation and the time of high rotation can be reduced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-111748 | Jul 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/010369 | 3/9/2022 | WO |
