JP2743616B2 - Gear pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump for improving volumetric efficiency and reducing fluctuations in discharge pressure.

[0002]

6 and 7 show bearings 101 and 102 of a conventional gear pump. Inside a housing (not shown), inner peripheral surfaces 101a and 101a of the bearings 101 and 102 are shown.
The shaft portions 105 and 106 of the pair of fluid feed gears 103 and 104 are supported by 02a. Gear 1 for feeding fluid
The lubrication grooves 108 and 109 whose outer ends communicate with a low-pressure suction port 107 and the lubrication grooves whose outer ends communicate with a high-pressure discharge port 110 are provided on the side surfaces of the bearings 101 and 102 facing the main bodies 103a and 104a of the main bodies 03 and 104. 111 and 112 are formed.

By forming the lubrication grooves 108, 109, 111, 112 on the side surfaces of the bearings 101, 102, the feed fluid can be supplied to the gear bodies 103a, 104a and the bearing 10a.
Lubricating fluid is introduced between the side surfaces of the gears 1 and 102 to prevent galling and seizure between the gears 103 and 104 and the bearings 101 and 102. In particular, the gears 103, 104
Is helical or the lubricating feed fluid flows out of the housing from both sides of the gears, the gears 103 and 104 engage with each other and the amount of fluid outflow to the outside of the housing causes imbalance between the gears 103 and 104.
4 generates a thrust force. In such a case, introducing the feed fluid between the gear bodies 103a, 104a and the side surfaces of the bearings 101, 102 is equivalent to the operation of the gears 103, 104.
This is effective in preventing galling and seizure between the bearings and the bearings 101 and 102.

[0004]

In the conventional gear pump, the inner ends of the lubrication grooves 108, 109, 111, 112 formed on the side surfaces of the bearings 101, 102 correspond to the bearings 10 and 10, respectively.
1 and 102 communicated with the inner peripheral surfaces 101a and 102a. Then, the inner peripheral surface 1 of the bearings 101 and 102
The gear side of 01a and 102a is a chamfered portion R, and the gear side of the outer peripheral surface of the shaft portions 105 and 106 is a clearance groove 105a and 106a for polishing the side surface of the gear body. Lubrication grooves 111 and 112 communicating with 110 and lubrication grooves 108 and 109 having inner ends communicating with the suction port 107 communicate with each other via the chamfered portion 12 and the relief grooves 105a and 106a. That is, since the discharge port 110 and the suction port 107 communicate with each other, there is a problem that the fluid flows backward from the discharge port 110 to the suction port 107 as shown by an arrow in FIG.

Another problem is that pressure fluctuations on the suction side are transmitted to the discharge side, and pressure fluctuations on the discharge side increase.
In particular, in the case of a gear pump arranged in the middle of a molding line for forming a high-viscosity polymer sent from a screw extruder into a thin plate, the pressure fluctuation of the polymer sent out by the screw extruder is large. Needs to be reduced by a gear pump. In such a case, if the pressure fluctuation propagates from the suction side to the discharge side, the pressure fluctuation on the discharge side of the gear pump becomes large, and there is a problem that the thickness of the molded product becomes uneven.

An object of the present invention is to provide a gear pump which can solve the above-mentioned problems of the prior art.

[0007]

The present invention is characterized in that the shafts of a pair of fluid feed gears are supported by the inner peripheral surface of the bearing, and the side surface of the bearing opposes the body of the fluid feed gear. A lubrication groove having an outer end communicating with the suction port and a lubrication groove having an outer end communicating with the discharge port, wherein the inner end of each lubrication groove has a root circle of the fluid feed gear. Is located radially inward and radially outward of the inner peripheral surface of the bearing, and does not include the same diameter as the inner peripheral surface.

[0008]

According to the structure of the present invention, the outer end of the lubrication groove formed on the side surface of the bearing communicates with the suction port and the discharge port, and the inner end is located radially inward of the root circle of the fluid feeding gear. Therefore, the feed fluid can be introduced as a lubricating fluid from the suction port and the discharge port through the lubrication groove between the fluid feeding gear body and the side surface of the bearing.

Also, since the inner end of each lubrication groove is located radially outward of the inner peripheral surface of the bearing and does not include the same diameter as the inner peripheral surface, the outer end communicates with the suction port. There is no communication between the lubrication groove and the lubrication groove whose outer end communicates with the discharge port.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

The gear pump 1 shown in FIGS. 1 and 2 is used for feeding a high-viscosity resin liquid extruded from a screw extruder, and the fed resin liquid is solidified and formed into a sheet by a molding machine. Rolled up. The gear pump 1 includes a housing 2 and a pair of fluid feed gears 3 and 4 that mesh with each other in the housing 2.

The housing 2 has a cylindrical main body 5 and a front cover 7 attached to one end of the main body 5 with bolts 6.
And a rear cover 9 attached to the other end of the main body 5 with bolts 8. The body 5 has a fluid inlet 1
0a and a discharge port 10b are formed. The housing 2 is covered by a heater (not shown) for heating the fluid.

One of the gears 3 is on the driving side and includes a driving gear body 11 having teeth formed on the outer periphery thereof, and driving shaft portions 12 and 13 extending from the driving gear body 11 in both axial directions. , Each drive shaft portion 12, 13 is a cylindrical bearing 14, 15
Are supported by the inner peripheral surfaces 14a and 15a.

The other gear 4 is on the driven side and includes a driven gear body 16 having teeth formed on the outer periphery thereof, and driven shaft portions 17 and 18 projecting from the driven gear body 16 in both axial directions. The driven shaft portions 17 and 18 are cylindrical bearings 19 and 2
0 are supported by the inner peripheral surfaces 19a and 20a.

The fluid is fed by a space surrounded by the outer peripheral surface of the teeth of the drive gear body 11, the outer peripheral surface of the teeth of the driven gear body 16, the inner peripheral surface of the housing body 5, and the bearings 14, 15, 19, and 20. When a passage is formed and the drive gear 3 is driven to rotate, the fluid is sucked in from the suction port 10a and discharged from the discharge port 10b through the fluid feed passage.

Each of the drive shaft portions 12 and 13 protrudes out of the housing 2 and protrudes from the front cover 7 side.
Is connected to an unillustrated drive source.

A labyrinth seal 30 is formed to regulate the outflow of fluid from between the outer periphery of each of the drive shaft portions 12 and 13 and the housing 2. That is, the first cylindrical member 31 is fitted to the outer periphery of the drive shaft portions 12 and 13 protruding from the housing 2, and the second cylindrical member 32 covering the first cylindrical member 31 is attached to the housing 2 by bolts 33. First
A labyrinth seal 30 is formed between the outer peripheral surface of the cylindrical member 31 and the inner peripheral surface of the second cylindrical member 32. A passage 34 for the cooling medium is formed in the second cylindrical member 32.
Cooling medium inlet 35 and cooling medium outlet 36 leading to
Are formed. Thus, by adjusting the viscosity of the fluid flowing out between the housing 2 and the outer periphery of the drive shaft portions 12 and 13 by the cooling medium, the outflow amount can be adjusted.

In order to lubricate the minute gaps between the side surfaces of the bearings 14, 15, 19, 20 and the gear bodies 11, 16 with the feed fluid, the gear bodies 11, 16 of the bearings 14, 15, 19, 20 are lubricated. , Three lubrication grooves 25, 26, and 27 are formed respectively.

In each of the bearings 14, 15, 19 and 20,
The first lubrication groove 25 has an outer end communicating with the suction port 10a, an inner end radially inward of the root circle of the fluid feed gears 3, 4, and inner peripheral holes of the bearings 14, 15, 19, 20. 14a, 15
a, 19a, 20a. The outer end of the second lubrication groove 26 communicates with the discharge port 10b.
The inner ends are radially inward of the tooth root circles of the fluid feed gears 3 and 4 and the inner peripheral holes 14a and 15a of the bearings 14, 15, 19 and 20.
It is located radially outward of 19a and 20a. The third lubrication groove 27 has an outer end communicating with the fluid feed passage between the suction port 10a and the discharge port 10b, and an inner end having the bearings 14, 15, and 1.
It communicates with the inner peripheral surfaces 14a, 15a, 19a, and 20a of 9, 20. As shown in FIG. 3, an axial lubrication groove 28 communicating with the inner end of the third lubrication groove 27 is formed on each bearing inner peripheral surface 14a, 15a, 19a, 20a. The gear side of each bearing inner peripheral surface 14a, 15a, 19a, 20a is formed as a curved chamfer R.

According to the gear pump 1 having the above structure, the outer ends of the first lubrication grooves 25 of the bearings 14, 15, 19, 20 communicate with the suction port 10a, and the second lubrication grooves 26 correspond to the discharge ports 10b.
And the third lubrication groove 27 communicates with the fluid feed passage, so that the gear bodies 11, 16 and the bearings 14, 15, 19, 2
The feed fluid is introduced as a lubricating fluid between the side of
Galling and seizure between the gears 3, 4 and the bearings 14, 15, 19, 20 are prevented.

A first end whose outer end communicates with the suction port 10a.
The inner end of the lubrication groove 25 and the inner end of the second lubrication groove 26 whose outer end communicates with the discharge port 10b are connected to each bearing inner peripheral surface 14a, 1
5a, 19a, 20a
The first lubrication groove 25 and the second lubrication groove 26 do not communicate with each other via the chamfer R. Thereby, the suction port 10a
And the discharge port 10b do not communicate with each other through the lubrication grooves 25 and 26, so that the volumetric efficiency is improved, the propagation of the pressure from the suction side to the discharge side is reduced, and the pressure fluctuation of the discharge fluid is reduced. .

Specifically, the volumetric efficiency could be improved by 12 to 13%, and the pressure fluctuation on the discharge side could be reduced by 7 to 8%. In addition, as shown in FIG. 4, the diameter of the roots of the fluid feed gears 3, 4 is Di, and as shown in FIG. When Dk is used, the diameter Dm at the inner end position of the lubrication grooves 25 and 26 is, for example, Dm = Dk + [(Di−Dk)
× X], and it is preferable that the value X is determined experimentally in accordance with the viscosity of the fluid and the capacity of the gear pump.

[0023]

According to the gear pump of the present invention, the lubricating groove formed on the side surface of the bearing facing the gear body for fluid feeding supplies the lubricating fluid between the gear body and the side surface of the bearing. As a result, seizure and galling can be prevented, and since the discharge port and the suction port do not communicate with each other through the lubrication groove, the volumetric efficiency can be improved and the fluctuation of the fluid pressure on the discharge side can be reduced. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a gear pump according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the gear pump according to the embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of the bearing according to the embodiment of the present invention.

FIG. 4 is a diagram showing a formation position of a lubrication groove according to the embodiment of the present invention.

FIG. 5 is a diagram showing a formation position of a lubrication groove according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating the operation of a conventional example.

FIG. 7 is a diagram illustrating the operation of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gear pump 3, 4 Gear 10a Suction port 10b Discharge port 12, 13, 17, 18 Shaft part 14, 15, 19, 20 Bearing 25, 26 Lubrication groove

Claims (1)

(57) [Claims] 1. A shaft portion of a pair of fluid feeding gears is supported by an inner peripheral surface of a bearing, and a lubrication groove having an outer end communicating with a suction port is provided on a side surface of the bearing opposed to a body of the fluid feeding gear. ,
In a gear pump in which an outer end is formed with a lubrication groove communicating with a discharge port, an inner end of each lubrication groove is radially inward of a root circle of the fluid feed gear and a diameter of an inner peripheral surface of the bearing. A gear pump, which is arranged at a position outward in the direction and not including the same diameter as the inner peripheral surface thereof.