JP2000205144A - Inscribing gear pump and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inscribing gear pump having good discharging efficiency and its manufacturing method. SOLUTION: A piston 60 is provided with a through hole 62 to make sliding contact with the periphery of another piston 56, which is arranged slidable within the through hole 62. Via a through hole 64 formed in the piston 60, a fluid is introduced between the pistons 56 and 60 and a lid 12, and when the discharge pressure acts on the pistons 56 and 60 through the fluid, the pistons 56 and 60 approach a driving gear 26 and a follower gear 22 and press them to the inner bottom part 16. This prevents or suppresses gap formation between the driving gear 26 and follower gear 22 and the inner bottom part 16. Even in case a crescent 40 protrudes from the gears 26 and 22 to generate an obstacle for the piston 60 moving, the piston 56 can press the driving gear 26, which allows suppressing the drop of the described actions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal gear pump used for supplying a fluid such as water or machine oil or applying a fluid pressure such as a hydraulic pressure, and a method of manufacturing the same.

[0002]

2. Description of the Related Art By rotating a driving gear having external teeth and a driven gear having internal teeth meshing with the external teeth of the driving gear, a suction portion provided in a housing accommodating these gears. An example of an internal gear pump that draws in a fluid such as water or oil from the outlet and discharges it from a discharge portion is disclosed in
No. 293452.

[0003] The internal gear pump disclosed in this publication will be briefly described. A housing for accommodating each gear (referred to as a casing in the publication) is provided with a pressure for guiding a discharge pressure on a side surface facing a driven gear. A plurality of introduction grooves are formed, and the discharge pressure guided by the pressure introduction grooves presses the driven gear against the inner bottom (the inner side surface) of the housing, thereby preventing the inclination of the axis of the driven gear.

[0004]

However, in the internal gear pump disclosed in the above publication, the discharge pressure causes the driven gear to be displaced by pressing the driven gear against the inner bottom of the housing.
A gap is formed on the side opposite to the inner bottom portion of the housing via the driven gear and the driving gear. When such a gap occurs, the discharge pressure leaks to the suction section side, and the fluid conveyed to the discharge section leaks to the suction section side via the gap, resulting in poor volumetric efficiency.

Incidentally, by rotating a pair of external gears housed in such a manner as to be meshed with each other in the housing with respect to such an internal gear pump, one of the gears is separated from a line connecting the centers of the gears. A circumscribed gear pump that transports a fluid from a suction unit provided on the side of the oil pump to a discharge unit provided on the other side is also generally used. In particular, in this type of circumscribed gear pump, a side plate is provided on one end side in the axial direction of each gear, and the side plate is pressed against each gear by the pressure of the fluid that has entered the side opposite to the gear of the side plate due to an increase in the internal pressure of the discharge section. Further, a so-called pressure-loading type external gear pump is generally employed in which each gear is pressed against the bottom of the housing by the pressure from the side plate to reduce or eliminate the gap between the gear and the bottom of the housing.

In the above publication, a gap is formed on the side opposite to the inner bottom of the housing of the driven gear because the discharge pressure is applied directly to the driven gear.
A side plate is provided on the side opposite to the inner bottom portion of the driven gear housing, and if the discharge pressure is applied to the driven gear indirectly via the side plate, the side plate creates a gap on the side opposite to the inner bottom portion of the driven gear housing. It is easy to imagine a configuration that is small or eliminated.

However, as in the internal gear pump disclosed in the above publication, a general internal gear pump is provided with a partition member called a crescent or a partition plate, and the driving force is applied to such a partition member. By contacting the tips of the external teeth of the gear and the internal teeth of the driven gear, the discharge section side and the suction section side are partitioned. Here, since each gear rotates,
Abrasion with the bottom of the housing results in a small but small axial dimension. On the other hand, since the partition member basically does not wear in the direction along the axial direction of the gear, there is no dimensional change in that direction. As a result, a dimensional difference occurs between each gear and the partition member in a direction along the axial direction of each gear, and even if a side plate is provided, the side plate abuts on the partition member, and as a result, the side plate A gap is created between each gear and the problem of the above publication cannot be solved.

An object of the present invention is to provide an internal gear pump having high volume efficiency and a method of manufacturing the same in consideration of the above facts.

[0009]

According to a first aspect of the present invention, there is provided a driving gear having external teeth and a ring-shaped driven gear having internal teeth housed in a gear housing portion inside a housing in a state of being meshed with each other. By rotating the driving gear, the fluid contained in each tooth groove of the driving gear and the driven gear is conveyed to the rotation direction side of the driving gear and the driven gear, and the driving force of the driving gear and the driven gear is shifted from the meshing portion of the driving gear and the driven gear. A fluid is sucked from the outside of the housing via a suction portion provided in the housing on the downstream side in the rotation direction of the gear and the driven gear, and a discharge portion provided on the rotation direction upstream side of the meshing portion with the fluid. An internal gear pump that discharges fluid to the outside of the housing, and abuts against each tooth tip of the driving gear and the driven gear on a side opposite to the meshing portion through a center of the driving gear. A partition member that divides a space between the driven gear and the driving gear into a space on the discharge section side and a space on the suction section side, and an inner bottom portion of the gear housing section via the driving gear. The driving gear opposes the driving gear along the axial direction of the driving gear on the opposite side, and is lateral to the partition member along the direction orthogonal to the axial direction and the driving gear relative to the axial direction. A first piston provided so as to be capable of moving toward and away from, and a space on the suction unit side of a space separated by the partition member from a space opposite to the driving gear via the first piston. Intercepting means for interrupting communication with the motor, and introducing the discharge pressure for discharging the fluid on the discharge portion side to the outside of the housing via the discharge portion to the side opposite to the driving gear via the first piston. And a unit.

According to the internal gear pump having the above configuration, the driving gear housed in the housing starts to rotate, and the driven gear whose internal teeth mesh with the external teeth of the driving gear in conjunction with the rotation of the driving gear. When the gear rotates, the outer teeth of the driving gear and the inner teeth of the driven gear in the meshing portion of the driving gear and the driven gear and the space between the driving gear and the driven gear separated by the partition member on the suction side. The fluid contained in each tooth space is conveyed to the discharge section side in the space between the driving gear and the driven gear. In this way, the fluid is conveyed to the discharge unit side, so that the internal pressure of the space on the discharge unit side, that is, the discharge pressure increases, and the fluid is discharged to the outside of the housing via the discharge unit.

The discharge pressure is guided to the back side of the first piston via the introduction portion (that is, the side opposite to the driving gear via the first piston), and the guided discharge pressure presses the first piston. To move closer to the driving gear. Thus, the first piston approaching the driving gear presses the driving gear, so that the driving gear is pressed against the inner bottom portion of the housing. Therefore, the first gear of the driving gear is discharged from the discharge portion side through the side opposite to the first piston. Leakage of the discharge pressure to the suction part side is prevented or suppressed.

Since the first piston is provided on the side of the partition member in a direction perpendicular to the axial direction of the driving gear, the first piston moves along the axial direction of the driving gear. Even so, the first piston does not come into contact with the partition member. Therefore, the driving gear is reliably pressed by the first piston that has received the discharge pressure.

In addition, the space between the space on the back surface side of the first piston and the space on the suction portion side of the space between the driving gear and the driven gear separated by the partition member is completely or completely shut off by a blocking means. Since most of the pressure is blocked, leakage of the discharge pressure guided to the back surface side of the first piston to the suction portion side is prevented or suppressed.

In the present invention, the first piston may be configured to press all or part of the driving gear, and if the first piston is configured to press all or part of the driving gear, the first piston may be pressed. The other parts may press the driven gear.

According to a second aspect of the present invention, in the internal gear pump according to the first aspect, the shut-off means is provided in the axial direction of the driven gear at a side opposite to the inner bottom portion of the gear housing via the driven gear. A second piston provided so as to be able to move toward and away from the driven gear along
A space opposite to the driven gear is communicated with the introduction portion via a piston.

In the internal gear pump having the above structure, the second piston as the shut-off means is provided so as to be movable toward and away from the driven gear along the axial direction of the driven gear.
When the discharge pressure from the introduction portion is guided to the opposite side of the driven gear via the piston, the second piston approaches the driven gear and presses the driven gear, thereby pressing the driven gear against the inner bottom of the housing. Therefore, the inclination of the axis of the driven gear is restricted, and the gap between the driven gear and the inner bottom of the housing is reduced or eliminated.

Here, when the second piston faces the partition member along the axial direction of the driven gear, the end of the partition member opposite to the inner bottom of the housing projects beyond the second piston. In this case, the second piston that has received the discharge pressure comes into contact with the partition member, so that the driven gear cannot be pressed, and the above-described operation cannot be performed.

However, in this case, the gap between the driven gear and the second piston is reduced or eliminated by moving the second piston until it contacts the partition member. Therefore, the leakage of the discharge pressure between the second piston and the driven gear is reduced or eliminated.

In the present invention, the second piston does not have to face the partition member along the axial direction of the driven gear. In this case, the second piston that has received the discharge pressure always presses the driven gear and presses the driven gear against the inner bottom of the housing.

According to a third aspect of the present invention, in the internal gear pump according to the first or second aspect, a part of the first piston faces the driven gear along an axial direction of the driven gear. It is characterized by being arranged.

In the internal gear pump having the above structure, a part of the first piston is opposed to the driven gear along the axial direction of the driven gear, so that the first piston receives the discharge pressure guided by the introduction portion. The driven gear as well as the driven gear receives the pressing force from the first piston and is pressed against the inner bottom of the housing. Therefore, the inclination of the axis of the driven gear is restricted, and the gap between the driven gear and the inner bottom of the housing is reduced or eliminated.

According to a fourth aspect of the present invention, in the internal gear pump according to the third aspect, the first piston is closer to the discharge portion than a virtual line connecting the center lines of the driving gear and the driven gear. It is characterized by being provided.

In the internal gear pump having the above structure, the first piston is provided closer to the discharge portion than the imaginary line connecting the center lines of the driving gear and the driven gear. The pressing force from the pressed first piston acts on portions of the driving gear and the driven gear near the discharge portion.

Here, the discharge pressure is increased by the rotation of the driving gear and the driven gear, and the fluid contained in the tooth space of each gear is conveyed to the discharge portion side. As described above, the internal pressure of the space on the side of the discharge section is used.

On the other hand, on the suction portion side, the meshing between the driving gear and the driven gear, which have been meshing up to that point, is released (that is, the external teeth of the driving gear and the internal teeth of the driven gear are removed from the tooth grooves into which they have entered, respectively). To get out)
Negative pressure is generated corresponding to the volume occupied by the external teeth or the internal teeth in the tooth space of each gear. Since the fluid is sucked into the housing through the suction portion by the negative pressure, the internal pressure does not act to separate the gears from the inner bottom of the housing on the suction portion side.

Therefore, as described above, the inclination of the axes of the driving gear and the driven gear can be reduced only by applying a pressing force to the driving gear and the driven gear on the discharge portion side and pressing the driving gear and the driven gear against the inner bottom of the housing. In addition, the clearance between the driving gear and the driven gear and the inner bottom of the housing can be reduced or eliminated.

According to a fifth aspect of the present invention, in the internal gear pump according to any one of the first to fourth aspects, the first piston is moved to an end face of the driving gear facing the first piston. It is characterized in that first biasing means for biasing in the direction of approach is provided.

According to the internal gear pump having the above structure, the first
Since the piston is urged toward the driving gear by the first urging means, the first piston is in close contact with the driving gear before the fluid is guided to the side opposite to the driving gear of the first piston.

Here, if a gap is formed between the first piston and the driving gear before the internal gear pump starts operating, the fluid is discharged through this gap after the internal gear pump starts operating. Side to the suction side, resulting in reduced volumetric efficiency. However, according to the present invention, as described above, in the state before the first urging means guides the fluid to the side opposite to the driving gear of the first piston, that is, in the state before the start of the operation of the internal gear pump, the first bias is applied. Since the piston is brought into close contact with the driving gear, the volumetric efficiency in a state immediately after the start of the operation of the internal gear pump can be improved.

According to a sixth aspect of the present invention, in the internal gear pump according to any one of the second to fifth aspects, the second piston is moved to an end face of the driven gear that faces the second piston. It is characterized in that a second urging means for urging in the approaching direction is provided.

According to the internal gear pump having the above structure, the second
Since the piston is urged toward the driven gear by the second urging means, the second piston comes into close contact with the driven gear or the partition member before the fluid is guided to the side opposite to the driven gear of the second piston. ing.

Here, if there is a gap between the second piston and the driven gear before the internal gear pump starts operating, the fluid is discharged through this gap after the internal gear pump starts operating. Side to the suction side, resulting in reduced volumetric efficiency. However, according to the present invention, as described above, in the state before the fluid is guided to the opposite side of the second piston from the driven gear by the second urging means, that is, in the state before the start of the operation of the internal gear pump, the second piston is in the second state. Since the piston is brought into close contact with the driven gear or the partition member, the volumetric efficiency in a state immediately after the start of the operation of the internal gear pump can be improved.

According to a seventh aspect of the present invention, a driving gear having external teeth and a ring-shaped driven gear having internal teeth, which are housed in a gear housing portion inside the housing, are rotated while meshing with each other. The fluid contained in the tooth grooves of the driving gear and the driven gear is conveyed to the rotation direction side of the driving gear and the driven gear, and the rotation of the driving gear and the driven gear is shifted more than the meshing portion of the driving gear and the driven gear. A fluid is sucked from the outside of the housing through a suction portion provided in the housing on the downstream side in the direction, and to the outside of the housing via a discharge portion provided on the rotation direction upstream side from the meshing portion. A method of manufacturing an internal gear pump that discharges fluid, wherein a gear housing portion in which the driving gear and the driven gear are housed is disposed on a side opposite to the meshing portion via a center of the driving gear. A partition member is provided which abuts against each tooth tip of the driving gear and the driven gear and divides a space between the driven gear and the driving gear into a space on the discharge section side and a space on the suction section side. , On the side of the partition member along a direction orthogonal to the axial direction of the driving gear, on the side opposite to the inner bottom of the gear housing portion due to the pressure of the fluid guided to the side opposite to the driving gear. Closing the opening end of the gear housing so that the first piston pressing the driving gear toward the inner bottom of the gear housing can be moved along the axial direction of the driving gear by an external force of a predetermined magnitude or more. Attach to the lid,
Mounting a blocking means for blocking communication between the space on the side opposite to the driving gear and the space on the suction portion side of the space partitioned by the partition member via the first piston; In a state before fixing the portion to the opening end of the gear housing portion and fixing the lid portion to the opening end of the gear housing portion, the lid portion and the first piston along the axial direction of the driving gear. Is set longer than the state after the lid is fixed to the open end of the gear housing.

According to the method of manufacturing the internal gear pump having the above configuration, the partition member is disposed in the gear housing portion of the housing in which the driving gear and the driven gear are housed, on the side opposite to the meshing portion via the center of the driving gear. Since the tooth tips of the driving gear and the driven gear are in contact with the partition member, the space between the driven gear and the driven gear is divided into a space on the discharge section side and a space on the suction section side.

Before and after the arrangement of the partition member, a first piston is attached to the lid. The first piston is
When the fluid is guided to the side opposite to the driving gear of the first piston, the lid is located on the side of the partition member along the direction perpendicular to the axial direction of the driving gear with the lid fixed, when the fluid is guided, The driving gear is pressed against the inner bottom of the gear housing by pressure from the side opposite to the inner bottom of the gear housing. Since the driving gear is pressed against the inner bottom of the housing by the first piston, leakage of the discharge pressure from the discharge section side to the suction section side via the side opposite to the first piston of the driving gear is prevented or suppressed. .

Here, the first piston is attached to the lid so as to be located on the side of the partition member along a direction perpendicular to the axial direction of the driving gear, so that the first piston is mounted on the shaft of the driving gear. Even if it moves along the direction, the first piston does not contact the partition member. Therefore, the driving gear is reliably pressed by the first piston that has received the discharge pressure.

Further, before or after the attachment of the first piston, suction of the space defined by the partition member and the space opposite to the driving gear via the first piston with the lid fixed is performed. Blocking means for blocking communication with the space on the side of the unit is attached to the housing. All or most of the space between the space on the back surface side of the first piston and the space on the suction portion side of the space between the driving gear and the driven gear partitioned by the partition member is blocked by the blocking means. This prevents or suppresses the discharge pressure guided to the back surface side of the first piston to the suction portion side.

In this manufacturing method, before the lid is fixed to the opening end of the gear housing, the distance between the lid and the first piston along the axial direction of the driving gear is determined by the distance between the lid and the first piston. The length is set to be longer than the state after being fixed to the opening end of the gear housing. Therefore, when fixing the lid, the first piston comes into contact with the driving gear before the lid comes into close contact with the opening end of the gear housing. Therefore, no gap is formed between the driving gear and the first piston immediately after the completion of the assembly.

If there is a gap between the first piston and the driving gear before the internal gear pump starts operating, the fluid is discharged through this gap after the internal gear pump starts operating. Side to the suction side, resulting in reduced volumetric efficiency. However, according to the present invention, as described above, since the first piston is already in close contact with the driving gear immediately after assembly, the volume efficiency in the state immediately after the start of operation of the internal gear pump can be improved. .

According to an eighth aspect of the present invention, in the method for manufacturing the internal gear pump according to the seventh aspect, the inner gear pump is provided so as to face the driven gear and the partition member along the axial direction of the driving gear, At the first position along the axial direction.
A second piston having a through-hole through which a piston can slide is used as the blocking means, and in a state before the lid is fixed to the open end of the gear housing, the second piston extends along the axial direction of the driving gear. The first piston holds the second piston in a state in which the distance between the lid and the second piston is set longer than the state after the lid is fixed to the open end of the gear housing. It has been characterized.

According to the manufacturing method of the internal gear pump having the above-described structure, the first piston is slidably disposed along the axial direction of the driving gear in the through hole formed in the second piston as the blocking means. When the discharge pressure is guided to the opposite side of the second piston from the driven gear, the second piston approaches the driven gear and presses the driven gear, thereby pressing the driven gear against the inner bottom of the housing. Therefore, the inclination of the axis of the driven gear is restricted, and the gap between the driven gear and the inner bottom of the housing is reduced or eliminated.

Here, when the second piston faces the partition member along the axial direction of the driven gear, the end of the partition member opposite to the inner bottom of the housing projects beyond the second piston. In this case, the second piston that has received the discharge pressure comes into contact with the partition member, so that the driven gear cannot be pressed, and the above-described operation cannot be performed.

However, in this case, the gap between the driven gear and the second piston is reduced or eliminated by moving the second piston until it contacts the partition member. Therefore, the leakage of the discharge pressure between the second piston and the driven gear is reduced or eliminated.

By the way, in the present manufacturing method, before the lid is fixed to the open end of the gear housing,
The distance between the lid and the second piston along the axial direction of the driving gear is set to be longer than the state after the lid is fixed to the open end of the gear housing, and in this state, Two pistons are held by the first piston. Therefore, when fixing the lid portion, the second piston contacts the driven gear or the partition member before the first piston contacts the driving gear. Therefore, no gap is formed between the driven gear or the partition member and the first piston immediately after the completion of the assembly.

If there is a gap between the second piston and the driven gear or the partition member before the operation of the internal gear pump starts, the fluid flows through this gap after the operation of the internal gear pump starts. Leaks from the discharge unit side to the suction unit side, and as a result, the volumetric efficiency decreases. However, according to the present invention, as described above, since the second piston is already in close contact with the driven gear or the partition member immediately after assembly, the above-mentioned gap is eliminated or reduced, so that the operation of the internal gear pump is performed. The volume efficiency in the state immediately after the start can be improved.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Configuration of First Embodiment> FIG.
The internal gear pump 1 according to the first embodiment of the present invention
FIG. 3 is an exploded perspective view, and FIG. 3 is a plan view of the internal gear pump 10 excluding the lid 12. FIG. 1 is a sectional view taken along line 1-1 in FIG.

As shown in FIGS. 1 and 4, the internal gear pump 10 has a housing 18 composed of a lid 12 and a housing body 14.

The housing body 14 has an inner bottom 16 as a whole.
The cover 12 has a substantially disk shape having an outer diameter substantially equal to the outer diameter of the housing body 14, and is fastened with a bolt or the like in a state of contacting the open end of the housing body 14. The housing body 14 is fixed to the housing body 14 by means, and one end in the axial direction of the housing body 14 is closed.

The inside of the housing body 14 is a gear housing portion 20 having a circular shape in a plan view, and a cylindrical or ring-like driven gear 22 is housed inside the gear housing portion 20. The driven gear 22 is a spur-toothed internal gear having a plurality of internal teeth 24 formed on an inner peripheral portion thereof, and has an outer diameter slightly smaller than an inner diameter of the gear housing 20. The gear housing 20 is rotatable substantially coaxially. Further, as shown in FIG. 1, the axial dimension of the driven gear 22 is sufficiently shorter than the axial dimension of the gear housing 20.

A driving gear 26 is provided inside the driven gear 22.
Is arranged. The driving gear 26 has external teeth 28
Is provided with the gear main body 30 formed. Gear body 30
Is smaller in diameter than the driven gear 22 and the number of external teeth 28 is
Fewer. The gear body 30 is provided such that its axial height is substantially equal to the axial height of the driven gear 22 and its center of rotation is eccentric with respect to the center of rotation of the driven gear 22 along the axis orthogonal direction. The external teeth 28 mesh with the internal teeth 24 of the driven gear 22. A gear shaft 32 extends coaxially from one axial end of the gear body 30, and is rotatably supported by a bearing 34 formed on the inner bottom 16 so as to be rotatable around its own axis. Also, the gear shaft 3
The distal end of the second member penetrates the bearing 34 and is mechanically connected directly or mechanically to a driving means such as a motor through a mechanical movement transmitting means such as a gear, and receives the driving force of the driving means. This allows it to rotate around its own axis.

In the present embodiment, the driving gear 26 and the driven gear 22 are configured as spur gears, but other gears such as a helical gear may be applied.

On the other hand, a gear shaft 36 extends coaxially from the other end of the gear body 30 in the axial direction.
Is fixed to the housing body 14, the lid 12
Through the circular hole 38 formed in the hole.

A crescent 40 as a partition member is arranged inside the housing body 14. As shown in FIG. 3, the crescent 40 is located on the side opposite to the portion where the external teeth 28 and the internal teeth 24 mesh with each other via the center of rotation of the gear body 30 (the driving gear 26). And the external teeth 28 of the gear body 30.

The dimension (height) of the crescent 40 in the direction along the axial direction of the driving gear 26 and the driven gear 22 is substantially equal to or slightly equal to the axial height of the gear body 30 of the driving gear 22 and the driven gear 22. large. Also, Crescent 40
Is approximately crescent-shaped in plan view, and one end in the width direction of the driving gear 26 facing the external teeth 28 is curved with a radius of curvature substantially equal to the radius of curvature of a circle connecting the tips of the external teeth 28. It has a concave shape. The longitudinal dimension of the crescent 40 at one end in the width direction is longer than the pitch of the external teeth 28 of the gear body 30 (the driving gear 26), and when the driving gear 26 rotates around its own axis. At least one external tooth 28 always faces one end in the width direction of the crescent 40 along the direction orthogonal to the axis of the driving gear 26.

On the other hand, the other end in the width direction of the driven gear 22 on the side facing the internal teeth 24 is stretched toward the driven gear 22 with a radius of curvature substantially equal to the radius of curvature of the circle connecting the tips of the internal teeth 24. It is curved so that it comes out. The longitudinal dimension at the other end in the width direction of the crescent 40 is longer than the pitch of the internal teeth 24 of the driven gear 22, and when the driven gear 22 rotates around its own axis, at least one of the inner gears is always formed. The teeth 24 face the other end in the width direction of the crescent 40 along the direction orthogonal to the axis of the driving gear 26.

Here, in a state where the tip of the external teeth 28 abuts on one end in the width direction of the crescent 40 and the tip of the internal teeth 24 abuts on the other end in the width direction of the crescent 40,
The contact between the external teeth 28 and the internal teeth 24 and the crescent 40 and the meshing part between the internal teeth 24 and the external teeth 28 allow a space between the driven gear 22 and the driving gear 26 to serve as a suction portion described later. Space 42 on the side of suction hole 46 communicating with suction hole 46
And a space 44 on the side of the discharge hole 48 communicating with the discharge hole 48 as a discharge portion. These spaces 42, 44 are partitioned by the driving gear 26, the driven gear 22, and the crescent 40.

A suction hole 46 as a suction portion is formed in the inner bottom portion 16 corresponding to the space 42.
A discharge hole 48 is formed in the inner bottom portion 16 as a discharge portion. When the internal gear pump 10 is applied, for example, as one configuration of an electronically controlled hydraulic braking device of a vehicle, the suction hole 46 communicates with a storage portion (oil tank or the like) of the brake oil, and discharges. The hole 48 communicates with a cylinder or the like provided on a caliper or the like of a brake.

Further, as shown in FIG.
A pair of bottomed circular holes 50 are formed at the end of the crescent 40 on the side opposite to the above, and one longitudinal end of a columnar pin 52 is inserted into each of the circular holes 50.
The other end of the pin 52 in the longitudinal direction protrudes from the crescent 40 and, as shown in FIG. 1, perpendicularly to the inner bottom 16 through a pair of bottomed holes 54 formed in the inner bottom 16. That is, it is inserted (parallel to the gear shafts of the driving gear 26 and the driven gear 22). Thereby, a direction parallel to the inner bottom portion 16 (that is, the driving gear 26
And the relative movement of the crescent 40 with respect to the inner bottom 16 in the direction orthogonal to the axis of the driven gear 22).

On the other hand, as shown in FIGS. 1 and 4, a piston 56 as a first piston is arranged on the side of the driving gear 26 on the gear shaft 36 side. The piston 56 has a disk shape as a whole, and a circular through hole 58 through which the gear shaft 36 penetrates is formed at the center thereof.
The outer diameter of the piston 56 is substantially equal to the diameter of the tip of the driving gear 26 (the diameter of a virtual circle connecting the tips of the outer teeth 28 of the driving gear 26), and is coaxial with the gear body 30. And can be moved toward and away from the gear body 30 along the axial direction of the driving gear 26.

Further, a piston 60 as a blocking means or a second piston is provided inside the gear housing portion 20. The piston 60 is formed in a disk shape as a whole, and is slidable along the axial direction of the gear housing 20 (that is, along the axial direction of the driven gear 22) inside the gear housing 20. The outer peripheral portion of the gear 60 is in sliding contact with the inner peripheral portion of the gear housing portion 20 (note that in FIG.
A gap is formed between the outer peripheral portion of the gear housing 0 and the inner peripheral portion of the gear housing portion 20.
0 are separated from each other for the sake of convenience in illustration, and it should be understood that there is actually no gap between the outer peripheral portion of the piston 60 and the inner peripheral portion of the gear housing 20. ). The piston 60 has an inner diameter dimension of the piston 5.
A circular through-hole 62 slightly larger than the outer diameter of No. 6 is formed. The center of the through hole 62 is formed eccentrically with respect to the center of the piston 60. When the piston 60 is disposed inside the gear housing 20, the through hole 62 and the driving gear 26 are substantially coaxial. The piston 56 described above is accommodated inside the through hole 62 so as to be movable along the axial direction of the driving gear 26, and the outer peripheral portion of the piston 56 is in sliding contact with the inner peripheral portion of the through hole 62.

Further, a through hole 64 is formed in the piston 60 as an introduction portion. The through hole 64 has a smaller diameter than the through hole 62, but penetrates in the thickness direction of the piston 60 like the through hole 62. Further, the through hole 64 is formed at a position eccentric from the center of the piston 60, and accommodates the piston 56 inside the through hole 62 in a state where the piston 60 is arranged inside the gear housing portion 20, and The gear shaft 3 of the driving gear 26 is inserted into the through hole 58 of the piston 56.
The space 44 communicates with the through hole 64 in a state where the hole 6 is made to penetrate.

<Operation and Effect of First Embodiment>
The operation and effect of the present embodiment will be described.

In the internal gear pump 10, the driving gear 26
3 rotates in the direction of arrow A in FIG. 3 under the driving force of a driving means such as a motor, the driven gear 22 in which the internal teeth 24 mesh with the external teeth 28 of the driving gear 26 starts to rotate. In this state, the fluid such as water or oil in the tooth space 78 between the internal teeth 24 adjacent to each other and the tooth space 80 between the external teeth 28 adjacent to each other in the space 42 flows into the driven gear 22 and the driving gear 22. 26
And is conveyed into the space 44. Drive gear 2
6 is smaller than the inner diameter of the driven gear 22 and the driving gear 26 is eccentric with respect to the driven gear 22, so that the outer teeth 28 and the inner teeth 24 are formed through the center of the driving gear 26. The driving gear 26 and the driven gear 22 are farthest apart from each other on the side opposite to the meshing portion, but the crescent 4
0, and each tip of the internal teeth 24 and the external teeth 28 is always in contact with the widthwise end of the crescent 40,
Basically, the internal teeth 24 and the external teeth 2 are provided through the center of the driving gear 26.
8 is divided into a space 42 and a space 44, and these spaces 42 and 44 are
And the internal teeth 24 and the external teeth 28 contacting the crescent 40.

In the space 44, the fluid in the tooth groove 78 of the driven gear 22 and the tooth groove 80 of the driving gear 26
The internal teeth 24 mesh with the internal teeth 24 and the external teeth 28 are pushed into the tooth grooves 78 by the internal teeth 24 entering the tooth grooves 80. This allows
In the space 44, the amount of fluid increases and the internal pressure of the space 44 increases, and the increased internal pressure becomes a discharge pressure, and discharges the fluid in the space 44 to the outside of the housing 18 through the discharge hole 48.

On the other hand, with the rotation of the driving gear 26 and the driven gear 22 on the space 42 side, the external teeth 28 come out of the tooth grooves 78 and the internal teeth 24 come out of the tooth grooves 80, so that the tooth grooves 78 are kept there. As a result, a negative pressure is generated in the space 42 by an amount corresponding to the volume occupied by the external teeth 28 and the volume occupied by the internal teeth 24 in the tooth space 80, and the inside of the space 42 is Fluid is sucked from the outside of the housing 18.

As described above, the driving gear 26 and the driven gear 2
By rotating 2, the fluid is sucked from the suction hole 46 and the fluid is discharged from the discharge hole 48, so that a so-called pump function is achieved.

A part of the fluid in the space 44 is guided to the back side of the piston 60, that is, between the piston 60 and the lid 12 through the through hole 64 by the discharge pressure.
It is guided between the piston 56 and the lid 12. Piston 6
The fluid guided between the lids 0 and 56 and the lid 12 presses the piston 56 in the direction of approaching the driving gear 26 and the piston 60 in the direction of approaching the driven gear 22 by the discharge pressure. In this way, the pistons 56 and 60 pressed by the fluid approach the driving gear 26 and the driven gear 22 and press the driving gear 26 and the driven gear 22 to move the driving gear 2.
6 and the driven gear 22 are pressed against the inner bottom 16.

Thus, the driving gear 26 and the driven gear 2
Formation of a gap between the inner gear 2 and the inner bottom portion 16 can be prevented or suppressed. Fluid enters the gap from the space 44 side, and the fluid raises the driving gear 26 and the driven gear 22 by the discharge pressure. In addition, the inclination of the driven gear 22 (that is, the inclination of the axes of the driving gear 26 and the driven gear 22) can be prevented. Therefore, in the internal gear pump 10, the drive gear 26 and the driven gear 22 can be prevented from being partially reduced. In addition, since the formation of the gap can be prevented or suppressed, leakage of the fluid from the space 44 to the space 42 through the gap can be prevented or suppressed, and the volume efficiency can be improved.

Here, in the internal gear pump 10, the driving gear 26 and the driven gear 22
As described above, the outer peripheral portion of the piston 60 is in sliding contact with the inner peripheral portion of the gear housing portion 20, and the outer peripheral portion of the piston 56 is in contact with the piston 60. The fluid guided between the pistons 56, 60 and the lid 12 is driven by the fluid from portions other than the through holes 64 through the pistons 56, 60 because the fluid is in sliding contact with the inner periphery of the through holes 64 formed in the through hole. There is no leakage to the gear 26 and the driven gear 22 side. In addition, each piston 56, 60 presses the driving gear 26 and the driven gear 22 by the discharge pressure from the fluid,
At this time, the pistons 56 and 60 come into close contact with the driving gear 26 and the driven gear 22, so that no gap is formed between the pistons 56 and 60 and the driving gear 26 and the driven gear 22. Therefore, basically, there is no leakage of the fluid from the space 44 to the space 42 on the side of the lid portion 12 with respect to the driving gear 26 and the driven gear 22, and therefore, the volumetric efficiency of the internal gear pump 10 is reduced. Can be improved.

Incidentally, as described in the item of the problem to be solved by the invention, the driving gear 26 and the driven gear 22
The rotation causes friction between the inner bottom portion 16 and the inner bottom portion 16, and as a result, as shown in FIG. 2, the driving gear 26 and the driven gear 22 are worn, so that the axial height is slightly reduced. It is possible. In such a case, no friction occurs between the crescent 40 and the inner bottom portion 16, so that the height of the crescent 40 does not decrease.
0 of the drive gear 26 and the driven gear 22
More protruding. In this state, even if the piston 60 is displaced in a direction to approach the driven gear 22, the piston 60 contacts the crescent 40 before contacting the driven gear 22, and cannot contact the driven gear 22. Therefore, in this case, the piston 60 cannot press the driven gear 22 even when the discharge pressure from the fluid is applied.

On the other hand, since the piston 56 has an outer diameter less than or equal to the tip diameter of the driving gear 26 and is coaxially arranged with respect to the driving gear 26, the discharge pressure is applied by the fluid. It approaches the driving gear 26 without being hindered by the crescent 40 and presses the driving gear 26.

Accordingly, formation of a gap between the driving gear 26 and the inner bottom 16 can be prevented or suppressed in substantially the same manner as when the crescent 40 does not protrude beyond the driving gear 26 and the driven gear 22. The driven gear 22 is connected to the piston 6
Although no pressing force can be obtained from zero, the driving gear 26
The driven gear 22 and the inner bottom portion 1 are supported by the driving gear 26 at a portion where the driven gear 22 meshes with the driven gear 26.
6 is prevented from being formed. As described above, in the internal gear pump 10, although there is a possibility that the function is slightly reduced, even when the crescent 40 protrudes from the driving gear 26 and the driven gear 22, substantially the same effects as those described above are obtained. Obtainable.

Further, in a state where the crescent 40 protrudes from the driving gear 26 and the driven gear 22, the piston 60 comes into contact with the crescent 40 by applying the discharge pressure from the fluid even if the piston 60 cannot press the driven gear 22. Move up to. Therefore, the driven gear 22 and the piston 6
0 can be suppressed to about the size difference between the crescent 40 and the driven gear 22. For this reason, a decrease in volumetric efficiency can be suppressed.

In the present embodiment, the outer peripheral portion of the piston 60 is merely slid on the inner peripheral portion of the gear accommodating portion 20. A sealing material having a small friction resistance and a high sealing property may be provided on at least one of the peripheral portions.
Similarly, at least one of the outer peripheral portion of the piston 56 and the inner peripheral portion of the through hole 64 may be provided with a sealing material having a small frictional resistance and a high sealing property.

In the present embodiment, the outer diameter of the piston 56 is set to be smaller than the diameter of the tip of the driving gear 26, and
Although the configuration is such that it is arranged coaxially with the driving gear 26, the configuration of the piston 56 is not limited to this. In other words, the piston 56 only needs to be disposed at a position that does not face the crescent 40 along the axial direction of the driving gear 26 and at least faces the driving gear 26 along the axial direction thereof. Therefore, the piston 56 is configured such that a part thereof is opposed to the driven gear 22 along the axial direction of the driven gear 22, and the piston 56 presses not only the driving gear 26 but also the driven gear 22 by applying discharge pressure from the fluid. It does not matter.

<Configuration of Second Embodiment> Next, another embodiment of the present invention will be described. In the following description, portions that are basically the same as those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

FIG. 7 is an exploded perspective view showing the structure of an internal gear pump 90 according to a second embodiment of the present invention. FIG. 6 shows a state where a cover 92 of the internal gear pump 90 is removed. Is shown in plan view. FIG. 5 is a sectional view taken along line 5-5 in FIG.

As shown in FIGS. 5 and 7, the internal gear pump 90 has a lid 92 as a shutoff means.
The internal gear pump 10 according to the first embodiment is different from the first embodiment in that the lid 92 closes the open end of the housing body 14 in which the gear housing 20 is formed.
Is the same as that of the lid 12. However, as shown in FIG. 5, basically, the lid 92, the driving gear 26 and the driven gear 22
There are no inclusions such as pistons 56 and 60 between them.

As shown in FIG. 5, the lid 92 has a bottomed piston accommodating portion 94 which is open toward the driving gear 26 and the driven gear 22 when attached to the housing body 14. A block-shaped piston 96 as a first piston is accommodated therein.

The piston accommodating portion 94 corresponds to the space 44 along the axial direction of the driving gear 26 and the driven gear 22 when the lid 92 is attached to the housing main body 14. When viewed along the axial direction of the piston 22 (that is, the state shown in FIG. 6), all or most of the space 44 surrounded by the outer shape of the driving gear 26 and the driven gear 22 and the outer shape of the crescent 40 is
Overlaps with 4. However, even in such a case, the piston accommodating portion 94 does not overlap the crescent 40.

On the other hand, the outer shape of the piston 96 accommodated in the piston accommodating portion 94 corresponds to the inner shape of the piston accommodating portion 94.
6 and the driven gear 22 are slidably in contact with the inner peripheral portion of the piston accommodating portion 94 so as to be movable in the axial direction.

Further, as shown in FIG.
6 has a through hole 98 as an introduction portion. One end of the through hole 98 is open on the side of the driving gear 26 and the driven gear 22, and the other end is open on the bottom side of the piston housing 94.

<Operation and Effect of Second Embodiment> In the internal gear pump 90 having the above-described structure, the fluid in the space 44 is supplied to the piston housing 9 through the through hole 98 by the discharge pressure.
4 and the piston 96
Is pressed in a direction to approach the driving gear 26 and the driven gear 22. Piston 96 to which discharge pressure is applied from fluid
Presses the driving gear 26 and the driven gear 22 toward the driving gear 26 and the driven gear 22, and presses the portion corresponding to the space 44 of the driving gear 26 and the driven gear 22 against the inner bottom 16.

Here, as described in the first embodiment, the inclination of the driving gear 26 and the driven gear 22 is such that the fluid that has entered between the driving gear 26 and the driven gear 22 and the inner bottom 16 is The reason is that the driving gear 26 and the driven gear 22 are lifted by the discharge pressure. However, in the internal gear pump 90, the space 4 is pressed by the pressing force from the piston 96.
Since the driving gear 26 and the driven gear 22 are pressed against the inner bottom 16 on the side 4, the fluid in the space 44 does not enter between the driving gear 26 and the driven gear 22 and the inner bottom 16. Therefore, the discharge pressure is not applied to the inner bottom 16 side ends of the driving gear 26 and the driven gear 22, and the driving gear 26 and the driven gear 22 are not inclined.

Further, as described above, the piston housing 9
4 when viewed along the axial direction of the driving gear 26 and the driven gear 22, all or most of the space 44 surrounded by the outer shape of the driving gear 26 and the driven gear 22 and the outer shape of the crescent 40 is Because the piston 96 overlaps, the piston 96 housed in sliding contact with the piston housing 94 presses the driving gear 26 and the driven gear 22 (that is, the piston 96 comes into contact with the driving gear 26 and the driven gear 22, The piston 9 is located between the lid 92 and the space 44.
Blocked by 6. For this reason, leakage of the fluid from the space 44 to the space 42 through the gap between the driving gear 26 and the driven gear 22 and the lid 92 can be reduced or prevented, and the discharge pressure can be improved.

Further, as described above, even when the piston accommodating portion 94 is viewed along the axial direction of the driving gear 26 and the driven gear 22, the piston accommodating portion 94 does not overlap the crescent 40. Therefore, even when the piston 96 approaches the driving gear 26 and the driven gear 22, the piston 96 does not contact the end of the crescent 40 on the side of the lid 92. For this reason, even if the driving gear 26 and the driven gear 22 wear and the end of the crescent 40 on the lid 92 side protrudes from the driving gear 26 and the driven gear 22, the piston 96 that has received the discharge pressure from the fluid can surely be formed. The driving gear 26 and the driven gear 22 are pressed.

Further, since the outer peripheral portion of the piston 96 is in sliding contact with the inner peripheral portion of the piston accommodating portion 94, the piston 96
Fluid that has entered between the piston 96 and the bottom of the piston housing 94 does not leak from between the outer periphery of the piston 96 and the inner periphery of the piston housing 94.

<Configuration of Third Embodiment> Next, a third embodiment of the present invention will be described.

FIG. 8 is a sectional view of an internal gear pump 110 according to a third embodiment of the present invention. As shown in this figure, in the internal gear pump 110, the shape of the piston 112 as the first piston is different from the piston 56 of the internal gear pump 10 according to the first embodiment, and the disk-shaped large diameter Part 114 and this large diameter part 114
A cylindrical small-diameter portion 116 having an outer diameter smaller than that of the cylindrical portion is integrally formed coaxially, the small-diameter portion penetrates the circular hole 38, and the small-diameter portion 116 and the large-diameter portion 114 are coaxially formed. The gear shaft 36 penetrates the formed through hole 118.

Note that even when the piston 112 is formed in the above-described shape, the substantial operation does not change at all.

The cover 12 of the internal gear pump 110
A plurality of (two in the present embodiment) spring receiving holes 120 are formed in the surface of the side facing the inner bottom portion 16 in a state where the lid portion 12 is assembled to the housing main body 14. The opening of each of these spring receiving holes 120 is opposed to one axial end of the large-diameter portion 114 along the axial direction of the piston 112, and a compression coil spring 122 as a biasing means is accommodated inside each of them. Have been.

The natural length of these compression coil springs 122 (ie, the length in the state where no external force is applied to the compression coil springs 122) is determined by the internal gear pump 1
10 from the dimension from the bottom of the spring receiving hole 120 to the inner bottom 16 along the axial direction of the driving gear 26 in a state where the assembly of the driving gear 26 is completed,
Is longer than the size obtained by subtracting the sum of the respective thicknesses of the gear body 30 of FIG.

On the other hand, a plurality of (two in the present embodiment) spring receiving holes 124 are formed on the surface of the lid 12 opposite to the inner bottom 16 in the radial direction of the lid 12 with respect to the spring receiving holes 120. Have been. The opening of each of these spring receiving holes 124 is opposed to one axial end of the piston 60 along the axial direction of the piston 60, and each of the spring receiving holes 124 has a compression coil spring 1 as an urging means.
26 are accommodated.

The natural length of these compression coil springs 126 (that is, the length when no external force is applied to the compression coil springs 126) is determined by the internal gear pump 1
The sum of the thicknesses of the driven gear 22 or the crescent 40 and the piston 60 is subtracted from the dimension from the bottom of the spring receiving hole 124 to the inner bottom 16 along the axial direction of the driving gear 26 in a state where the assembly of the driving gear 10 is completed. Longer than the dimensions.

<Operation and Effect of Third Embodiment> In the internal gear pump 110 having the above configuration, the piston 5
Since the piston 112 and the second piston 60 are provided as the first piston in place of 6, the same operation as the internal gear pump 10 according to the first embodiment is basically obtained, and the same effect is obtained. Can be.

The internal gear pump 110 has the compression coil springs 122 and 126 as described above. Since the natural lengths of the compression coil springs 122 and 126 are set to the above-described lengths, the compression coil springs 122 are not assembled in the assembled state of the internal gear pump 110.
Presses the large-diameter portion 114 of the piston 112 toward the inner bottom 16 with the urging force. As a result, the large diameter portion 114 is connected to one end of the gear body 30 in the axial direction (that is, the large diameter portion 114).
(The end on the side opposite to). Similarly, in the assembled state of the internal gear pump 110, the compression coil spring 126 presses the piston 60 toward the inner bottom 16 by the urging force. Thereby, the piston 60 is brought into close contact with one end in the axial direction of the driven gear 22 (that is, the end opposite to the piston 60) or the crescent 40.

As described above, in the internal gear pump 110, the large-diameter portion 114 is formed in the gear body 3 before the fluid is introduced between the lid portion 12 and the large-diameter portion 114 and the piston 60.
0 (drive gear 26) and a gap between the piston 60 and the driven gear 22 or the crescent 40 can be prevented.

Therefore, the large diameter portion 114 and the gear body 30 immediately after the operation of the internal gear pump 110 is started.
(The driving gear 26) and the gap between the piston 60 and the driven gear 22 or the crescent 40 from the space 44 to the space 42 (see FIG. 3) can be prevented from leaking fluid. In particular, the volume efficiency in the state immediately after the start of operation of the internal gear pump 110 can be improved.

In the present embodiment, the compression coil springs 122 and 126 are used as the urging means.
However, the present invention is not limited to this. Other springs, for example, leaf springs
And the piston 60. Further, an elastic member such as a rubber material other than a spring may be employed as the urging means, and may be disposed between the lid 12 and the large diameter portion 114 and the piston 60, and this rubber material may be used as the urging means.

<Structure of Fourth Embodiment> Next, a fourth embodiment of the present invention will be described.

FIG. 9 is a sectional view showing the configuration of an internal gear pump 140 according to a fourth embodiment of the present invention. As shown in FIG.
In FIG. 0, a through-hole 142 is formed in the vicinity of the outer peripheral portion of the lid 12 along the thickness direction, and the upper end of the peripheral wall of the housing body 14 (the end on the side facing the lid 12). A screw hole 144 is formed. A bolt 146 is provided through the through hole 142, and the cover 12 and the housing body 14 are integrated by screwing into the screw hole 144. In the present embodiment, in particular, these through holes 14
2, the bolt 146 and the screw hole 144 are shown and made visible,
In each of the above-described embodiments, means for integrating the lid 12 and the housing body 14 is not particularly described. However, in each of the above-described embodiments,
It should be understood that they are integrated by a similar configuration or other connection means.

A ring groove 148 is formed on the outer periphery of the small-diameter portion 116 of the piston 112 so as to open outward in the radial direction. An O-ring (holding means) is provided inside the ring groove 148. O-ring) 150 is fitted. Basically, the O-ring 150 seals the gap between the inner peripheral portion of the circular hole 38 and the outer peripheral portion of the small diameter portion 116.

Further, a ring groove 152 is formed on the outer periphery of the large diameter portion 114 of the piston 112 so as to open outward in the radial direction. An O-ring as a holding means is formed inside the ring groove 152. (O-ring) 154 is fitted. Basically, the O-ring 154 allows the outer peripheral portion of the large-diameter portion 114 and the through-hole 62 of the piston 60 to move.
The gap between the inner peripheral portion and the inner peripheral portion is sealed.

Although not described in each of the embodiments described above, O-rings 150 and 154 for sealing are used.
With regard to, it should be understood that the above-described embodiments basically have the same features.

<Assembly Method of Internal Gear Pump 140> Next, the operation and effects of the present embodiment will be described through an explanation of an assembling method of the internal gear pump 140.

In assembling the internal gear pump 140, first, as shown in FIG.
4, a driving gear 26 and a driven gear 2
2 and Crescent 40 are set. Before and after this, the small-diameter portion 1 of the piston 112 is inserted into the circular hole 38 of the lid portion 12.
16 and the large-diameter portion 11 of the piston 112.
4 is fitted into the through hole 62 of the piston 60. However, at this time, the dimension between the large diameter portion 114 and the lid 12 is
The size between the piston 60 and the lid 12 is made sufficiently larger than the size obtained by subtracting the sum of the thicknesses of the gear body 30 (the driving gear 26) and the large diameter portion 114 from the size between the inner bottom 2 and the inner bottom portion 16. The dimension between them is made sufficiently larger than the dimension between the lid part 12 and the inner bottom part 16 minus the sum of the thicknesses of the driven gear 22 and the piston 60.

In this state, the O-ring 150 is elastically deformed by the pressing force from the inner peripheral portion of the circular hole 38 by the small-diameter portion 116 being fitted into the circular hole 38.
Reaction force (elastic force) of the O-ring 150 against the inner circumference of the
The small-diameter portion 116 of the piston 112 is held by the frictional force between the O-ring 150 and the inner peripheral portion of the circular hole 38, and the relative movement of the piston 112 with respect to the lid 12 is restricted. Similarly, when the large diameter portion 114 is fitted into the through hole 62, the O-ring 15 is pressed by the pressing force from the inner peripheral portion of the through hole 62.
4 is elastically deformed, the pressing reaction force (elastic force) of the O-ring 154 against the inner peripheral portion of the through hole 62 and the O-ring 15
4 and the inner peripheral portion of the through hole 62, the piston 1
Twelve large diameter portions 114 are retained, and the relative movement of the piston 112 with respect to the piston 60 is restricted.

Next, from this state, the piston 60 is inserted into the inside of the housing body 14 and the respective through holes 14 are inserted.
2 is screwed into the screw hole 144. While tightening the bolt 146, gradually move the piston 6
0 is inserted inside the housing body 14, first,
As shown in FIG. 11, the end of the piston 60 on the inner bottom 16 side contacts the end of the driven gear 22 on the lid 12 side or the end of the crescent 40 on the lid 12 side. In this state, when the bolt 146 is further tightened to bring the lid 12 closer to the housing body 14, the relative movement of the O-ring 150 with respect to the lid 12 is restricted by the pressing reaction force and the frictional force (that is, the O-ring 150). Piston 1 through 150
The piston 112 (held at 12) attempts to move to the inner bottom 16 side.

On the other hand, since the relative movement of the piston 60 with respect to the piston 112 is restricted by the pressing reaction force and the frictional force of the O-ring 154, the piston 112
The piston 60 also attempts to move to the inner bottom 16 side by moving to the side. However, as described above, the piston 60 is already at the end of the driven gear 22 on the lid 12 side or the lid of the crescent 40 Since the piston 60 is in contact with the end on the 12th side, the piston 60 cannot move further to the inner bottom 16 side. Accordingly, the piston 60 whose relative movement with respect to the piston 112 is restricted, the piston 112 moves toward the inner bottom portion 16 side, and thereby the driven gear 22 has the end on the lid portion 12 side or the crescent 40 has the It is pressed against the end, and is brought into close contact with the end of the driven gear 22 on the side of the lid 12 or the end of the crescent 40 on the side of the lid 12. At this time, the pressing reaction force and the frictional force of the O-ring 154
0, the piston 60 is opposed to the piston 112 against the pressing reaction force and the frictional force.
, The pressing reaction force and the frictional force of the O-ring 154 further move the piston 60 to the end of the driven gear 22 on the lid 12 side or the lid 12 of the crescent 40.
To the side edge.

When the piston 60 is in close contact with the end of the driven gear 22 on the lid 12 side or the end of the crescent 40 on the lid 12 side, the bolt 146 is further tightened.
When the lid 12 is moved closer to the housing body 14, FIG.
As shown in FIG. 5, the large-diameter portion 114 of the piston 112 comes into contact with the lid-side end of the gear body 30 (the driving gear 26) before the lid 12 comes into contact with the housing body 14.
As described above, the relative movement of the piston 112 with respect to the lid 12 is restricted by the pressing reaction force and the frictional force of the O-ring 150. Therefore, as shown in FIG. 9, the bolt 146 is tightened until the lid 12 comes into contact with the housing main body 14 and the lid 12 and the housing main body 14 are integrated, and the lid 12 approaches the housing main body 14. When moved, the piston 112 also attempts to move. However, in this state, the large diameter portion 114 has already contacted the end of the gear body 30 on the lid portion 12 side, so the piston 112 cannot move further to the inner bottom portion 16 side.
Therefore, the relative movement with respect to the lid 12 is
2 is pressed against the end of the gear body 30 on the side of the cover 12 by the movement of the cover 12 approaching the housing body 14,
The gear body 30 is brought into close contact with the end on the lid 12 side.

At this time, since the pressing reaction force and the frictional force of the O-ring 150 try to hold the piston 112 as it is, the piston 112 moves against the lid 12 against the pressing reactional force and the frictional force. By being relatively displaced,
The pressing reaction force and the frictional force of the O-ring 150 further bring the piston 112 into close contact with the end of the gear body 30 (the driving gear 26) on the lid 12 side.

As described above, in the internal gear pump 140, the piston 112 is brought into close contact with the end of the gear body 30 on the side of the lid 12 at the time of completion of assembly, and the piston 60 is brought into contact with the end of the gear body 30 on the side of the lid 12. The piston 112 is attached to the end of the driven gear 22 on the side of the lid 12 or the end of the crescent 40 on the side of the lid 12.
And the end of the gear main body 30 on the side of the lid 12, and the end of the piston 60 and the driven gear 22 on the side of the lid 12, or
No gap is formed between the end of the crescent 40 on the side of the lid 12. Therefore, similarly to the third embodiment, it is possible to improve the volumetric efficiency in a state immediately after the start of operation of the internal gear pump 140.

In the third embodiment, the urging means such as the compression coil spring 122 and the compression coil spring 126 are used. However, in this embodiment, such a special member is used. Do not use at all. That is, since the O-ring 150 and the O-ring 154 as the relative displacement restricting means are generally members for the purpose of sealing and are necessary even if the above effects are not obtained, Therefore, the number of parts does not increase because of trying to obtain.

[0114]

As described above, according to the first aspect of the present invention, of the space between the driving gear and the driven gear partitioned by the partition member, the space on the suction portion side and the first piston. All or most of the space between the first piston and the back surface of the first piston can be blocked by the blocking means, so that leakage of the discharge pressure guided to the back surface of the first piston through the introduction portion to the suction portion can be prevented or suppressed. Efficiency can be improved. In addition, since the discharge pressure does not act on the driving gear but acts indirectly via the first piston, it is possible to prevent or suppress leakage of the discharge pressure between the first piston and the driving gear.
Further, since the movement of the first piston toward the driving gear is not restricted by the partition member, the first piston can be reliably moved even if the axial height of the driving gear decreases due to friction between the first piston and the housing. The driving gear can be pressed quickly, and the above effects can be maintained even when used for a long time.

According to the second aspect of the present invention, not only the effects of the first aspect of the present invention can be obtained, but also the driven gear can be mounted inside the housing by receiving the discharge pressure of the second piston as the shutoff means. It can be pressed against the bottom, and the inclination of the axis of the driven gear can be prevented or suppressed. Further, even if the movement of the second piston to the driven gear is restricted by the partition member, the second piston moves closer to the driven gear until the movement of the second piston is restricted by the partition member. The gap between the driven gear and the driven gear can be reduced, and leakage of the discharge pressure from the discharge section to the suction section through the gap can be suppressed. For this reason, the volumetric efficiency is improved.

Furthermore, according to the present invention described in claim 3, not only the effects of the present invention described in claim 1 or 2 are obtained, but also because the first piston presses not only the driving gear but also the driven gear. The inclination of the axis of the driven gear can be prevented or suppressed, and the leakage of the discharge pressure from the discharge part side to the suction part side between the driven gear and the inner bottom part of the housing can be prevented or suppressed, thereby further improving the volumetric efficiency. Can be improved.

Further, in the present invention described in claim 4, since the effect of the discharge pressure on the discharge portion side on the driving gear and the driven gear can be prevented or suppressed, the effect of the present invention described in claim 3 can be further improved with a small first piston. It can be obtained more efficiently.

Further, according to the present invention described in claim 5, not only the effects of the present invention described in any of claims 1 to 4 can be obtained, but also the fluid is moved to the side opposite to the driving gear of the first piston. Before the operation of the internal gear pump, the gap between the first piston and the driving gear can be eliminated in a state before the operation of the internal gear pump, and the volume efficiency in a state immediately after the operation of the internal gear pump is improved. be able to.

According to the sixth aspect of the present invention, not only the effects of the second aspect of the present invention but also the fluid of the second piston can be directed to the side opposite to the driven gear. Before the operation of the internal gear pump is started, that is, the gap between the second piston and the driven gear can be eliminated in a state before the start of the internal gear pump operation, thereby improving the volumetric efficiency in a state immediately after the start of the internal gear pump operation. be able to.

Further, in the internal gear pump manufactured by the method of the present invention as defined in claim 7, the space between the driving gear and the driven gear, which is partitioned by the partition member, on the suction side and the first piston. All or most of the space between the first piston and the rear surface of the first piston can be shut off by the shut-off means. Efficiency can be improved. In addition, since the discharge pressure does not act on the driving gear but acts indirectly via the first piston, it is possible to prevent or suppress leakage of the discharge pressure between the first piston and the driving gear. Further, since the movement of the first piston toward the driving gear is not restricted by the partition member, the first piston can be reliably moved even if the axial height of the driving gear decreases due to friction between the first piston and the housing. The driving gear can be pressed quickly, and the above effects can be maintained even when used for a long time. Moreover,
Since the first piston can be brought into close contact with the driving gear before starting the pump operation without using any special member, the volume efficiency immediately after the start of the operation can be improved.

The internal gear pump manufactured by the method of the present invention described in claim 8 can not only obtain the effect of the present invention described in claim 7, but also can function as a shut-off means in a state before the start of pump operation. Since the second piston can be brought into close contact with the driven gear or the partition member, the volume efficiency immediately after the start of operation can be improved without using any special member.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an internal gear pump according to a first embodiment of the present invention, which is a cross-sectional view taken along line 1-1 of FIG.

FIG. 2 is a cross-sectional view corresponding to FIG. 1, illustrating a state of a first piston and a second piston in a state where a partition member (crescent) protrudes from a driving gear and a driven gear.

FIG. 3 is a plan view of an internal gear pump according to a second embodiment of the present invention with a lid removed.

FIG. 4 is an exploded perspective view of the internal gear pump according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of the internal gear pump according to the second embodiment of the present invention, which is a cross-sectional view along line 5-5 in FIG.

FIG. 6 is a plan view of an internal gear pump according to a second embodiment of the present invention with a lid removed.

FIG. 7 is an exploded perspective view of an internal gear pump according to a second embodiment of the present invention.

FIG. 8 is a sectional view corresponding to FIG. 1 of an internal gear pump according to a third embodiment of the present invention.

FIG. 9 is a sectional view corresponding to FIG. 1 of an internal gear pump according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view corresponding to FIG. 9 and showing a state before assembling the pump.

FIG. 11 is a cross-sectional view corresponding to FIG. 10, showing a state in which a piston 60 as a second piston is in contact with a driven gear 22.

FIG. 12 is a cross-sectional view corresponding to FIG. 11, showing a state in which a piston 112 as a first piston is in contact with a driving gear 26.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 internal gear pump 16 inner bottom part 18 housing 22 driven gear 24 internal gear 26 driving gear 28 external gear 40 crescent (partition member) 46 suction hole (suction part) 48 discharge hole (discharge part) 56 piston (first piston) 60 piston (Second piston, shut-off means) 64 Through-hole (introduction part) 78 Tooth groove 80 Tooth groove 90 Internal gear pump 92 Lid (Shut-off means) 96 Piston (first piston) 98 Through-hole (introduction part) 110 Internal gear pump 112 piston (first piston) 122 compression coil spring (biasing means) 126 compression coil spring (biasing means) 140 internal gear pump

Continued on the front page (72) Inventor Kiyoji Nakamura 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3H041 AA01 AA02 BB03 CC03 CC20 DD04 DD05 DD22 DD23 DD25 DD27 DD38

Claims (8)

[Claims] 1. A driving gear having external teeth and a ring-shaped driven gear having internal teeth, which are housed in a gear housing portion inside a housing while meshing with each other, rotate the driving gear and the driven gear. The fluid contained in each tooth space is conveyed to the rotation direction side of the driving gear and the driven gear, and the housing is located downstream of the meshing portion of the driving gear and the driven gear in the rotation direction of the driving gear and the driven gear. An internal gear pump that sucks fluid from outside the housing through a suction portion provided and discharges fluid to the outside of the housing through a discharge portion provided on the rotation direction upstream side of the meshing portion. Wherein the contact between the driven gear and the driven gear by contacting each tooth tip of the driven gear and the driven gear on the side opposite to the meshing portion via the center of the driven gear A partition member that divides the space into a space on the discharge unit side and a space on the suction unit side, and along the axial direction of the driving gear on the side opposite to the inner bottom portion of the gear housing via the driving gear. Opposed to the driving gear, and at a side of the partition member along a direction perpendicular to the axial direction, a side provided to be movable toward and away from the driving gear in the axial direction. A first piston; blocking means for blocking communication between a space on the opposite side to the driving gear via the first piston and a space on the suction portion side of a space partitioned by the partition member; An introduction part for guiding a discharge pressure for discharging the fluid of the part side to the outside of the housing via the discharge part to a side opposite to the driving gear via the first piston. Gear pump. A second piston provided to be movable toward and away from the driven gear along an axial direction of the driven gear on a side opposite to an inner bottom portion of the gear housing via the driven gear. 2. The internal gear pump according to claim 1, wherein a space on the opposite side to the driven gear is communicated with the introduction portion via the second piston, as a blocking means. 3. 3. The internal gear pump according to claim 1, wherein a part of the first piston is arranged to face the driven gear along an axial direction of the driven gear. 4. The internal gear pump according to claim 3, wherein the first piston is provided closer to the discharge section than a virtual line connecting the center lines of the driving gear and the driven gear. 5. A first urging means for urging the first piston in a direction in which the first piston approaches an end face of the driving gear facing the first piston is provided.
The internal gear pump according to claim 4. 6. A second urging means for urging the second piston in a direction of approaching an end surface of the driven gear on a side facing the second piston.
An internal gear pump according to any one of claims 1 to 5. 7. A driving gear having external teeth and a ring-shaped driven gear having internal teeth housed in a gear housing portion inside a housing in a state of being meshed with each other, whereby the driving gear and the driven gear are rotated. The fluid contained in each tooth space is conveyed to the rotation direction side of the driving gear and the driven gear, and the housing is located downstream of the meshing portion of the driving gear and the driven gear in the rotation direction of the driving gear and the driven gear. An internal gear pump that sucks fluid from outside the housing through a suction portion provided and discharges fluid to the outside of the housing through a discharge portion provided on the rotation direction upstream side of the meshing portion. The manufacturing method according to any one of claims 1 to 3, wherein the driving gear and the driven gear are provided in a gear accommodating portion accommodating the driving gear and the driven gear on a side opposite to the meshing portion through the center of the driving gear. A partition member that abuts against each tooth tip and divides a space between the driven gear and the driving gear into a space on the discharge unit side and a space on the suction unit side; and a shaft of the driving gear. Along the side of the partition member along a direction orthogonal to the direction, the driving gear is moved from the side opposite to the inner bottom of the gear housing by the pressure of the fluid guided to the side opposite to the driving gear. A first piston that presses against an inner bottom portion of the gear housing is attached to a lid that closes an open end of the gear housing so as to be movable along an axial direction of the driving gear by an external force equal to or greater than a predetermined magnitude; A cover that attaches to the housing via a first piston a blocking unit that blocks communication between a space on the side opposite to the driving gear and a space on the suction unit side of the space partitioned by the partition member; To the open end of the gear housing In a state before the lid is fixed to the open end of the gear housing, the distance between the lid and the first piston along the axial direction of the driving gear is set to the lid. A method of manufacturing an internal gear pump, wherein the length is set to be longer than a state after being fixed to an open end of the gear housing portion. 8. A through-hole is provided along the axial direction of the driving gear so as to face the driven gear and the partition member, and the inside of the first piston can slide along the axial direction inside. The second piston is used as the blocking means, and before the lid is fixed to the open end of the gear housing, the lid and the second piston are arranged along the axial direction of the driving gear. The second piston is held by the first piston in a state where a distance between the first piston and the second piston is set longer than a state after the lid is fixed to the opening end of the gear housing. 8. The method for manufacturing an internal gear pump according to 7