JP2002013485A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of a device by rotatably supporting a shaft of a driving gear with a single bearing and decreasing the thickness of a side plate. SOLUTION: A shaft insertion hole 23A is provided on a cover element 23 composing a part of a pump housing 21. The shaft insertion hole 23A is formed to have a hole diameter corresponding to the outer diameter of a sleeve bearing 30 in the side plate 25 side. An end portion of the sleeve bearing 30 projecting out from the side plate 25 is fitted in the shaft insertion hole 23A of the cover element 23, and a driving shaft 28A of a driving gear 28 is rotatably supported with reference to the shaft insertion hole 23A of the cover element 23. The driving shaft 28A of the driving gear 28 is rotatably supported by using the single sleeve bearing 30 between the shaft insertion hole 23A of the cover element 23 and the side plate 25, and coaxiality between the driving shaft 28A and the sleeve bearing 30 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump suitably used as a hydraulic pressure source for, for example, a vehicle brake device.

[0002]

2. Description of the Related Art In general, gear pumps are used in various industrial fields as small and lightweight pumps because of their simple structure and high reliability.

A conventional gear pump of this type will be described with reference to FIG. 6. In the figure, reference numeral 1 denotes a pump housing forming an outer shell of the gear pump. The pump housing 1 includes a main body case 2 in which a cylinder hole 2 </ b> A having a bottom with a circular cross section is formed inside, and one end of the cylinder hole 2 </ b> A becomes a bottom 2 </ b> B, and is closed.
It is constituted by a lid 3 described later.

[0004] Reference numeral 3 denotes a lid constituting the pump housing 1 together with the main body case 2. The lid 3 is fixedly provided on the other side of the main body case 2 to close the opening end 2 C side of the main body case 2. I have. A shaft insertion hole 3A composed of a stepped hole is formed in the lid 3 in the axial direction, and a drive shaft 8A or the like described later is inserted into the shaft insertion hole 3A.
A rolling bearing 15 and the like described below that rotatably support A are provided.

Reference numeral 4 denotes a pump assembly disposed in the pump housing 1. The pump assembly 4 includes side plates 5, 6, a driving gear 8, a driven gear 9, and the like, which will be described later. Then, these side plates 5, 6, the drive gear 8 and the driven gear 9 are moved before being housed in the pump housing 1.
The pump assembly 4 is assembled by winding a metal coil spring 14, which will be described later, around the outer peripheral sides of the side plates 5, 6 and a seal block (not shown).

[0006] Reference numerals 5 and 6 denote a pair of side plates disposed so as to sandwich the drive gear 8 and the driven gear 9 from both the left and right sides in the figure. It is formed as a plate having a shape, and a gear chamber 7 is formed between the opposing surfaces. The side plates 5 and 6 are housed in the cylinder hole 2A of the main body case 2 together with the drive gear 8 and the driven gear 9 in an assembled state as the pump assembly 4.

Reference numeral 8 denotes a driving gear, and 9 denotes a driven gear disposed in the gear chamber 7 between the side plates 5 and 6 in a state of being meshed with the driving gear 8. Here, the drive gear 8 has a drive shaft 8A integrally extending in the left and right axial directions on both sides thereof, and the driven gear 9 similarly extends integrally in the left and right directions on both sides thereof. It has a driven shaft 9A. And this drive shaft 8
A and the driven shaft 9A are rotatably mounted on the side plates 5, 6 via sleeve bearings 10 to 13 described later.

The drive shaft 8A of the drive gear 8 is
A protruding end portion 3A is formed with a two-chamfered portion 8B as a connecting portion connected to an Oldham coupling 16 described later on the protruding end side. The protruding end side of the drive shaft 8A is rotatably supported by a later-described rolling bearing 15 in the shaft insertion hole 3A, and the drive gear 8 is driven to rotate by an external rotation source.

Reference numerals 10 and 11 denote left and right sleeve bearings provided on the side plates 5 and 6 for rotatably supporting the drive shaft 8A. The sleeve bearings 10 and 11 are cylindrical members having excellent wear resistance. It is formed as a plain bearing from a metal bush or the like, and its length dimension L (hereinafter referred to as shaft length L) is a dimension substantially corresponding to the thickness of the side plates 5 and 6. The sleeve bearings 10 and 11 have outer peripheral sides fitted and fixed in the side plates 5 and 6, and inner peripheral sides thereof are sliding surfaces that rotatably support the drive shaft 8 </ b> A.

Reference numerals 12 and 13 denote other sleeve bearings provided on the side plates 5 and 6 for rotatably supporting the driven shaft 9A.
The sleeve bearings 12 and 13 are formed of the same material as the sleeve bearings 10 and 11 and have an axial length L, and these are compatible with each other. The outer peripheral sides of the sleeve bearings 12 and 13 are fitted and fixed in the side plates 5 and 6, and the inner peripheral sides thereof are sliding surfaces that rotatably support the driven shaft 9A.

Reference numerals 14 and 14 denote annular metal coil springs as tightening ring members wound around the outer peripheral sides of the side plates 5 and 6 and the seal block.
With the side plates 5 and 6 and the seal block abutting each other, they are used to assemble them into a single pump assembly 4.

Reference numeral 15 denotes a rolling bearing provided in the shaft insertion hole 3A of the cover 3, and the rolling bearing 15 is made of, for example, a ball bearing or the like, and the drive shaft 8A of the drive gear 8 is inserted in the shaft insertion hole 3A. It is rotatably supported.

Reference numeral 16 denotes an Oldham coupling as a coupling member provided with a gap in the shaft insertion hole 3A of the lid 3. The Oldham coupling 16 has a chamfered portion 8B of one end of the drive shaft 8A.
And the other end is connected to a two-chamfered portion 17A of the output shaft 17.

Here, the output shaft 17 is provided on a rotation source (not shown) such as an electric motor, and is driven to rotate by this rotation source. The Oldham coupling 16 outputs the rotational output from the rotation source to the drive shaft 8A in a state where the output shaft 17 and the drive shaft 8A of the drive gear 8 are aligned (self-centering).
To communicate.

Reference numeral 18 denotes an oil seal as a sealing member provided in the shaft insertion hole 3A of the cover 3, and the oil seal 18 seals between the shaft insertion hole 3A of the cover 3 and the output shaft 17. And to prevent the pressure oil (oil liquid) in the pump housing 1 from leaking to the outside.

Further, reference numeral 19 denotes a suction port provided on the bottom portion 2B side of the main body case 2 and serving as a suction port for the oil liquid. The suction port 19 is formed between the seal block and the side plates 5 and 6. It communicates with a meshing portion of the drive gear 8 and the driven gear 9 via a suction passage (not shown) and the like, and sucks oil from an external oil storage tank (not shown) into the meshing portion.

In the prior art gear pump configured as described above, when a rotation source such as an electric motor is driven to rotate, the rotation output is transmitted from the drive shaft 8 A to the drive gear 8 via the output shaft 17 and the Oldham coupling 16. It is told to. When the drive gear 8 is driven to rotate, the driven gear 9 meshing with the drive gear 8 is rotated in the opposite direction.

The oil liquid guided from the suction port 19 side by the rotation of the driving gear 8 and the driven gear 9
Then, the liquid is sequentially fed to the outside of the seal block (to the cylinder hole 2A side) by the teeth of the driven gear 9, and the inside of the cylinder hole 2A is filled with high-pressure oil. Thus, the oil liquid in the cylinder hole 2A becomes high-pressure oil and is discharged from a discharge port (not shown) of the pump housing 1 to an external hydraulic device.

[0019]

By the way, the gear pump according to the prior art described above, the rotation of the drive gear 8 and the driven gear 9 causes the pump housing 1 to move from the suction port 19 side.
Oil is sequentially fed into the cylinder hole 2A of the cylinder hole 2A.
By filling the inside of A with a high-pressure oil liquid, high-pressure oil is discharged to the outside.

The pressure generated by the pressure oil in the cylinder hole 2A acts as a hydraulic reaction force on the driving gear 8 and the driven gear 9, and the hydraulic reaction force is applied to the pair of side plates 5 and 6 by the sleeve bearing 1.
0, 11 and the sleeve bearings 12, 13.

For this reason, the sleeve bearings 10 to 13 are required to be formed with at least a fixed length (for example, the shaft length L shown in FIG. 6) in order to secure sufficient durability against the hydraulic reaction force and life. Is required.

However, in the case of the prior art, the thickness of the side plates 5 and 6 is determined by the axial length L of the sleeve bearings 10 to 13. Therefore, the thickness of the side plates 5 and 6 can be further reduced. This makes it difficult to reduce the size and weight of the main body case 2 of the pump housing 1.

The drive shaft 8A of the drive gear 8 is connected to the side plates 5,
6, it is rotatably supported by sleeve bearings 10 and 11, and the protruding end of the drive shaft 8 </ b> A is rotatably supported by a rolling bearing 15 in the shaft insertion hole 3 </ b> A of the lid 3. In addition, it is difficult to keep the sleeve bearings 10, 11 and the offset bearing 15 coaxial with each other, and there is a problem that the workability during assembly is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to enable a shaft of a drive gear to be rotatably supported by using a single bearing, thereby reducing the work required during assembly. Another object of the present invention is to provide a gear pump that can improve the performance and can reduce the thickness of the side plate, and can reduce the size and weight of the device.

[0025]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a pump housing and a pair of side plates which are arranged in the pump housing to face each other and form a gear chamber between opposing surfaces. A drive gear and a driven gear, which are arranged in mesh with each other in a gear chamber between the pair of side plates and are provided with shafts on both sides, and the side plates for rotatably supporting the shafts of the drive gear and the driven gear. Applied to a gear pump including a plurality of bearings provided respectively.

A feature of the structure adopted by the first aspect of the present invention is that the pump housing has a shaft insertion hole through which a shaft on one surface of the drive gear is inserted to connect the shaft of the drive gear to a rotation source. And a bearing that supports a shaft on one surface side of the drive gear among the plurality of bearings extends toward a shaft insertion hole of the pump housing and is inserted into the shaft insertion hole of the pump housing. is there.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a gear pump according to an embodiment of the present invention; In the embodiments, the same components as those of the above-described conventional technology are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 1 to 4 show a first embodiment of the present invention. In the figure, reference numeral 21 denotes a pump housing which forms an outer shell of the gear pump. The pump housing 21 is substantially the same as the pump housing 1 described in the prior art, and has a main body case 22 having a circular cylinder hole 22A and a shaft. And a lid 23 having an insertion hole 23A.

However, the pump housing 21 has a reduced axial dimension between the main body case 22 and the lid 23, and is formed to be about 程度 to ３ shorter than the conventional one. In the bottom portion 22B of the main body case 22, a bottomed insertion hole 22C into which a drive shaft 28A described later is inserted with a gap together with the sleeve bearing 31, and a driven shaft 29 described later.
A and a bottomed insertion hole 22D into which A is inserted with a gap together with the sleeve bearing 33 are formed.

In the lid 23 having the opening end 22E side of the main body case 22 closed, a driven shaft 29A is radially separated from the shaft insertion hole 23A and is inserted with a gap together with a sleeve bearing 32 to be described later. Is formed. The shaft insertion hole 23A of the lid 23 is formed to have substantially the same hole diameter as the fitting holes 25A, 26A of the side plates 25, 26 described later. Note that a sleeve bearing 30 described later is inserted into the shaft insertion hole 23A with a gap of about several μm (micron).

A pump assembly 24 is provided in the pump housing 21. The pump assembly 24 includes side plates 25 and 26, a driving gear 28, a driven gear 29, a seal block 34, and the like, which will be described later. . The side plates 25, 26, the drive gear 28, the driven gear 29, and the seal block 34 move the metal coil springs 14 to the outer peripheral sides of the side plates 25, 26, and the seal block 34 before being housed in the pump housing 21. By winding
It is assembled as a pump assembly 24.

Reference numerals 25 and 26 denote a driving gear 28 and a driven gear 29.
1 and 4 are a pair of left and right side plates which are arranged opposite to each other so as to sandwich them from both the left and right sides, for example, as shown in FIGS. It is formed as an oval plate, and a gear chamber 27 is formed between the opposing surfaces. However, side plate 2
5 and 26 are formed of a thinner plate material than the side plates 5 and 6 described in the prior art, and sleeve bearings 30 to 3 to be described later.
The length in the axial direction is shorter than the shaft length L of No. 3.

As shown in FIG. 2, fitting holes 25A and 25B are formed in the side plate 25 so as to be radially separated from the driving gear 28 and the driven gear 29 and extend in the axial direction. Fitting holes 26A, 26B corresponding to mating holes 25A, 25B
Are drilled. And these fitting holes 25A, 2
5B, 26A, 26B, sleeve bearings 30, 3
2, 31, 33 are fitted.

Reference numeral 28 denotes a driving gear, and 29 denotes a driven gear disposed in a gear chamber 27 between the side plates 25 and 26 in a state of being meshed with the driving gear 8, and the driving gear 28 and the driven gear 29 The drive shaft 28A has substantially the same configuration as the drive gear 8 and the driven gear 9 described above, and extends integrally in the left and right axial directions.
And a driven shaft 29A.

However, the drive gear 28 and the driven gear 29 are reduced in length of the drive shaft 28A and the driven shaft 29A, and the drive shaft 28A and the driven shaft 29A are connected to the sleeve bearings 30-3.
3, the fitting holes 25A, 26A, 2 of the side plates 25, 26
It is rotatably mounted in 5B and 26B.

The drive shaft 28A of the drive gear 28 has a shaft portion on one side protruding into the shaft insertion hole 23A of the lid 23, and a protruding end of the drive shaft 28A connected to the Oldham coupling 16. A two-chamfered portion 28B is formed as a portion. The projecting end side of the drive shaft 28A is
A is driven to rotate integrally with the output shaft 17 via the Oldham coupling 16 in A.

Reference numerals 30, 31 denote left and right sleeve bearings provided on the side plates 25, 26 for rotatably supporting the drive shaft 28A. The sleeve bearings 30, 31 are the sleeve bearings 10, 31 described in the prior art. As in the case of No. 11, the shaft length L is compatible. The outer peripheral side of the sleeve bearings 30 and 31 has the fitting holes 25 of the side plates 25 and 26.
A and 26A are fitted by means of press-fitting or the like, and the inner peripheral side is a sliding surface that rotatably supports the drive shaft 28A.

The end of the sleeve bearing 30 projecting from the side plate 25 is fitted into the shaft insertion hole 23A of the cover 23, and the drive gear 28 is inserted into the shaft insertion hole 23A of the cover 23.
The drive shaft 28A is rotatably supported.

Reference numerals 32 and 33 denote other sleeve bearings provided on the side plates 25 and 26 for rotatably supporting the driven shaft 29A. The sleeve bearings 32 and 33 are also made of the same material as the sleeve bearings 30 and 31 described above. They are formed with an axial length L, which are mutually compatible. The outer peripheral side of the sleeve bearings 32, 33 is the side plates 25, 2
6 is press-fitted into the fitting holes 25B and 26B, and the inner peripheral side thereof is a sliding surface that rotatably supports the driven shaft 29A.

Numeral 34 is a seal block as a tooth tip seal member which constitutes a part of the pump assembly 24. The seal block 34 is made of, for example, an aluminum-based metal material or the like, as shown in FIGS. It is formed as a hexagonal block. The seal block 34 is provided so as to abut against the side plates 25 and 26 from the side, and is detachably attached to the side plates 25 and 26 by the respective metal coil springs 14 in this state.

Here, the seal block 34 is
The tooth tips of the gear 8 and the driven gear 29 are sealed, and a low-pressure chamber 36 described later is defined in the gear chamber 27 between the side plates 25 and 26. For this reason, the seal block 34 is
As shown in FIG. 4, the abutting surface side of the drive gear 28 and the driven gear 29 is cut out in a concave curved shape along the tooth tips of the driven gear 29 and the driven gear 29.
Lower arc surfaces 34A and 34B are provided.

The seal block 34 has a length dimension extending from one side surface of the side plate 25 shown in FIG. 1 to the other side surface of the side plate 26, and the arc surfaces 34A, 34B are formed on the side plates 25, 2 side.
6, a suction passage 35 communicating with the suction port 19 is formed as shown in FIG. And, this suction passage 35
Is for communicating the low pressure chamber 36 with the suction port 19 and is liquid-tightly shut off from the high pressure chamber 37 via a seal ring 39 described later.

Reference numeral 36 denotes a low-pressure chamber which is located in the gear chamber 27 between the side plates 25 and 26 and is defined between the drive gear 28, the driven gear 29 and the seal block 34. As shown in the figure, the seal block 34 is formed between the meshing portion of the drive gear 28 and the driven gear 29 and communicates with the suction port 19 for sucking oil from outside the pump housing 21 via the suction passage 35.

A high-pressure chamber 37 is formed between the cylinder hole 22A in the pump housing 21 and the pump assembly 24. The high-pressure chamber 37 is separated from the low-pressure chamber 36 and
8. A suction passage 3 formed around the driven gear 29 and formed in the pump assembly 24 by using each seal ring 39 described later.
5. It is separated from the low pressure chamber 36. And the high pressure chamber 3
Reference numeral 7 denotes a high-pressure oil liquid (pressure oil) filled inside by the rotation of the drive gear 28 and the driven gear 29.

That is, the driving gear 28 and the driven gear 29
By being rotationally driven in the directions indicated by arrows A and B in the middle, the oil liquid guided to the low pressure chamber 36 is sequentially sent to the surrounding high pressure chamber 37 side. Then, the high-pressure oil liquid sent into the high-pressure chamber 37 becomes pressure oil and is discharged from a discharge port 38 described later to the outside of the pump housing 21.

Reference numeral 38 denotes a discharge port formed in the pump housing 21. The discharge port 38 is formed on the bottom portion 22B of the main body case 22 as shown in FIGS. Always in communication. The discharge port 38 is for discharging the pressure oil filling the high-pressure chamber 37 toward an external brake device (not shown) or the like.

Further, reference numerals 39, 39 denote sealing rings as sealing members provided on the outer surfaces of the side plates 25, 26.
Each of the seal rings 39 is formed of an elastic resin material or the like in a substantially eyeglass shape as shown in FIG.
2 and the side plates 25 and 2 which are in contact with the bottom 22B and the lid 23.
6 is provided on the outer peripheral side of the end face. Each seal ring 39 seals the space between the pump housing 21 and the side plates 25 and 26 to shut off the inside of the pump assembly 24 from the high-pressure chamber 37.

The gear pump according to the present embodiment has the above-described configuration. Next, the operation of the gear pump will be described.

First, the drive gear 28 is driven by an external rotation source via the output shaft 17 and the Oldham coupling 16 as shown by an arrow A in FIG.
When driven in the direction, the driven gear 29 meshing with the drive gear 28 is driven to rotate in the direction of arrow B. The oil liquid guided to the low-pressure chamber 36 from the suction port 19 side by the rotation of the driving gear 28 and the driven gear 29 is transferred to the low pressure chamber 36 by the teeth of the driving gear 28 and the driven gear 29.
The liquid is sequentially fed to the high-pressure chamber 37 along A and 34B, and the high-pressure chamber 37 is filled with high-pressure oil.

The pressure oil in the high-pressure chamber 37 is discharged from the discharge port 38 of the pump housing 21 to the outside, and is supplied to, for example, a brake device of the vehicle via a hydraulic pressure control valve (not shown). , For performing vehicle brake control.

Here, in the present embodiment, the lid 2 constituting the pump housing 21 together with the main body case 22
3 is provided with a shaft insertion hole 23A, and the shaft insertion hole 23A is
The holes 25A and 26A have substantially the same diameter as the fitting holes 25A and 26A.

The end of the sleeve bearing 30 provided in the fitting hole 25A of the side plate 25 for rotatably supporting the drive shaft 28A of the drive gear 28 is inserted into the shaft insertion hole 23 of the lid 23.
A, and the drive shaft 28A of the drive gear 28 is rotatably supported also in the shaft insertion hole 23A of the lid 23.

Thus, the drive shaft 28A of the drive gear 28 can be rotatably supported between the shaft insertion hole 23A of the pump housing 21 (lid 23) and the side plate 25 using the single sleeve bearing 30. The coaxiality between the shaft center of the shaft 28A and the sleeve bearing 30 can be increased.

Therefore, the drive shaft 28A of the drive gear 28 can be smoothly supported by the sleeve bearing 30, and the drive shaft 28A
Can be uniformly stabilized. Then, the tooth tips of the driving gear 28 and the driven gear 29 and the arc surfaces 34A and 34B of the seal block 34 are concentrically held, and the side plates 25 and 26 are uniformly abutted against these arc surfaces 34A and 34B. Can be kept in condition.

As a result, the tooth tips of the drive gear 28 and the driven gear 29 are smoothly slid on the arc surfaces 34A and 34B of the seal block 34, and oil leakage between the two slid surfaces is satisfactorily reduced. Pump efficiency can be increased.

Further, the shaft length L of the sleeve bearings 30 to 33 is maintained at the same length as that of the prior art, and
5 and 26, the pump assembly 24
Of the pump housing 2
The axial dimensions of the main body case 22 and the lid 23 can be reduced, and the size and weight of the pump housing 21 can be reduced.

Further, the sleeve bearings 30 to 33 have a shaft length L.
With this configuration, the sleeve bearings 30 to 33 having sufficient durability against the hydraulic reaction force received from the high-pressure chamber 37 by the drive gear 28 and the driven gear 29 can be provided, and the life thereof can be reliably extended. Can be.

Therefore, according to the present embodiment, the drive shaft 28A of the drive gear 28 can be rotatably supported on the pump housing 21 and the side plate 25 by using the single sleeve bearing 30. In addition to reducing the number of parts,
Workability during assembly can be improved.

The thickness of the side plates 25 and 26 can be reduced.
The axial dimension of the entire pump assembly 24 can be reduced, and the axial dimensions of the main body case 22 and the lid 23 of the pump housing 21 can be reliably reduced, so that the size and weight of the pump housing 21 can be reduced.

Next, FIG. 5 shows a second embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted. It shall be. However, a feature of the present embodiment is that a shaft insertion hole 42A is provided in a lid 42 that constitutes the pump housing 41 together with the main body case 22, and a part of the side plate 43 is connected to the shaft insertion hole 42A.
A is provided by fitting into A.

The pump housing 41 comprises a main body case 22 and a lid 42 in substantially the same manner as the pump housing 21 described in the first embodiment. The lid 42 has a shaft insertion hole 42A. A bottom insertion hole 42B is formed. However, in the present embodiment, the shaft insertion hole 4
2A is formed with a hole diameter larger than the outer diameter of the sleeve bearing 30.

The side plate 43 has substantially the same structure as the side plate 25 described in the first embodiment, and has fitting holes 43A, 43A.
Despite having B, a cylindrical projection 43C is integrally formed on the side plate 43 coaxially with the fitting hole 43A. The cylindrical projecting portion 43C has its outer peripheral side inserted into the shaft insertion hole 42A of the lid 42 with a gap of, for example, about several μm (micron), and a sleeve bearing is provided on the inner peripheral side of the cylindrical projecting portion 43C. 3
0 is fitted using means such as press fitting as in the fitting hole 43A.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as those of the first embodiment can be obtained. In the present embodiment, the cylindrical projection 43C is integrally formed on the side plate 43, and the cylindrical projection 43C is inserted into the shaft insertion hole 42A of the lid 42. The bearing 30 can be stably supported by the side plate 43, and the shaft insertion hole 42
A can be stably supported.

In each of the above embodiments, the case where the gear pump is used as the hydraulic pressure source of the vehicle brake device has been described as an example. However, the present invention is not limited to this.
For example, the present invention can be applied to hydraulic power sources for various hydraulic circuits, such as a hydraulic power source for power steering.

[0065]

As described above in detail, according to the first aspect of the present invention, the bearing provided on the side plate for supporting the shaft on one surface side of the drive gear is extended toward the shaft insertion hole of the pump housing. Since the pump housing is configured to be inserted into the shaft insertion hole, the axial dimension of the entire pump housing can be reduced, and the size and weight of the pump housing can be reduced. In addition, the number of components can be reduced as compared with the prior art, and workability during assembly can be improved.

Further, the shaft on one side of the drive gear can be rotatably supported by using a single bearing between the shaft insertion hole of the pump housing and the side plate, and the coaxiality between the shaft of the drive gear and the bearing is increased. In addition, the eccentric rotation of the drive gear can be prevented, and the reliability of the gear pump is improved.

Further, since the coaxiality between the shaft of the drive gear and the bearing is increased, the shaft of the drive gear can be smoothly supported by a single bearing by the pump housing and the side plate, and the rotation of the shaft is made uniform and stabilized. In addition, the tips of the drive gear and the driven gear can be smoothly slid on the tooth seal member, oil leakage between the sliding surfaces can be reliably reduced, and pump efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a gear pump according to a first embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a main body case, a pump assembly, and the like in FIG. 1;

FIG. 3 is a sectional view of the gear pump as viewed from the direction of arrows III-III in FIG. 1;

FIG. 4 is a sectional view of the gear pump as viewed from the direction of arrows IV-IV in FIG. 1;

FIG. 5 is an enlarged longitudinal sectional view showing a gear pump according to a second embodiment.

FIG. 6 is a longitudinal sectional view showing a gear pump according to the related art.

[Explanation of symbols]

21, 41 Pump housing 22 Body case 23, 42 Lid 23A, 42A Shaft insertion hole 24 Pump assembly 25, 26, 43 Side plate 25A, 25B, 26A, 26B, 43A, 43B Fitting hole 27 Gear chamber 28 Drive gear 28A Drive shaft (shaft) 29 driven gear 29A driven shaft (shaft) 30 sleeve bearing (bearing) 31, 32, 33 sleeve bearing (bearing) 34 seal block (tooth seal member) 35 suction passage 36 low-pressure chamber 37 high-pressure chamber 38 discharge port

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H041 AA02 BB02 CC15 CC20 DD03 DD04 DD05 DD07 DD09 3H044 AA02 BB02 CC14 CC19 DD03 DD04 DD05 DD06 DD08

Claims (1)

[Claims] 1. A pump housing, a pair of side plates arranged in the pump housing to face each other and forming a gear chamber between opposing surfaces, and disposed in a gear chamber between the pair of side plates in a meshing state with each other. A drive gear and a driven gear provided with shafts on both surfaces thereof, and a plurality of bearings provided on each of the side plates for rotatably supporting the shafts of the drive gear and the driven gear. Has a shaft insertion hole through which a shaft on one surface of the drive gear is inserted to connect the shaft of the drive gear to a rotation source, and a bearing that supports the shaft on one surface of the drive gear among the plurality of bearings The gear pump according to claim 1, wherein the gear pump extends into a shaft insertion hole of the pump housing and is inserted into the shaft insertion hole of the pump housing.