JPH0530482U - Gear pump - Google Patents

Abstract

(57) [Summary] [Structure] On the side surface of the bearing 14 facing the body of the fluid feed gear, a suction side lubricating groove 25 having an outer end communicating with the suction port 10a,
A discharge-side lubrication groove 26 whose outer end communicates with the discharge port 10b is formed. An annular lubricating oil inlet 15 on the gear body side of the bearing 14
The inner ends of the lubricating grooves 25 and 26 are communicated with each other. Lubricating oil inlet
Inside the 15, there is provided a backflow prevention member 41 which blocks the flow of fluid from the discharge side lubricating groove 26 toward the suction side lubricating groove 25. [Effect] It is possible to improve volumetric efficiency and reduce fluctuations in fluid pressure on the discharge side.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gear pump for improving volumetric efficiency and reducing discharge pressure fluctuation.

[0002]

[Prior Art]

 6 and 7 show a bearing 101 of a conventional gear pump, in which a shaft portion 105, 106 of a pair of fluid feed gears 103, 104 is supported by an inner peripheral surface 101a of each bearing 101 inside a housing (not shown). Has been done. On the side surface of the bearing 101 facing the main bodies 103a and 104a of the fluid feeding gears 103 and 104, a suction-side lubrication groove 108 whose outer end communicates with a low-pressure suction port 107, and a high-pressure discharge port 110 on the outer end. A discharge-side lubrication groove 111 communicating with is formed.

By forming the lubricating grooves 108 and 111 on the side surfaces of the bearing 101 in this manner, the feed fluid is introduced as a lubricating fluid between the side surfaces of the gear bodies 103a and 104a and the side surfaces of the bearing 101, The gears 103 and 104 and the bearing 101 are prevented from galling and seizing. In particular, when the gears 103 and 104 are helical, or when the feed fluid, which has been made into a lubricating fluid, flows out of the housing from both sides of the gear, the meshing of the gears 103 and 104 and the outflow of the fluid to the outside of the housing can be prevented. Due to the balance, thrust force is generated in the gears 103 and 104. In such a case, introducing the feed fluid between the side surfaces of the gear main bodies 103a and 104a and the side surface of the bearing 101 is effective in preventing galling and seizure between the gears 103 and 104 and the bearing 101. It is effective.

The inner diameter of the bearing 101 is increased toward the gear bodies 103a and 104a by performing so-called crowning or chamfering on the gear body side. An annular lubricating oil introduction port 115 is formed which is surrounded by the side surfaces of 103a and 104a and the outer peripheral surfaces of the shaft portions 105 and 106. The inner ends of the lubricating grooves 108 and 111 are communicated with the lubricating oil introducing port 115. This promotes the inflow of fluid between the inner peripheral surface of the bearing 101 and the outer peripheral surfaces of the shaft portions 105 and 106, and seizure between the inner peripheral surface of the bearing 101 and the outer peripheral surfaces of the shaft portions 105 and 106. It effectively prevents galling.

[0005]

[Problems to be solved by the device]

 In the conventional gear pump, the inner ends of the lubricating grooves 108 and 111 formed on the side surface of the bearing 101 are communicated with the lubricating oil introducing port 115, so that the side surfaces of the gear bodies 103a and 104a and the side surface of the bearing 101 are connected. In addition to promoting the introduction of the fluid to the entire area between and, the introduction of the fluid from the discharge side lubrication groove 111 to the lubricating oil introduction port 115 is promoted.

However, when the discharge port side lubrication groove 111 and the suction side lubrication groove 108 communicate with the lubricating oil introduction port 115, the discharge port 110 and the suction port 107 communicate with each other. Therefore, as shown by the arrow in FIG. 6, the fluid flows backward from the discharge port 110 to the suction port 107 through the lubricating oil introduction port 115, and there is a problem that the volumetric efficiency decreases.

Further, when the discharge port 110 and the suction port 117 communicate with each other through the lubricating oil introduction port 115, there is a problem that the pressure fluctuation on the suction side is easily propagated to the discharge side and the pressure fluctuation on the discharge side becomes large. .. Especially in gear pumps that are placed in the middle of a molding line that molds high-viscosity polymer delivered from a screw extruder into a thin plate, the pressure variation of the polymer delivered by the screw extruder is large. It is necessary to reduce the fluctuation with a gear pump. That is, if the pressure fluctuation on the discharge side of the gear pump increases due to the propagation of the pressure fluctuation from the suction side to the discharge side, the thickness of the molded product becomes uneven.

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

[0009]

[Means for Solving the Problems]

 The feature of the present invention is that the shafts of a pair of fluid feeding gears are supported by the inner peripheral surface of the bearing, the side surface of the bearing facing the main body of the fluid feeding gear and the outer end of the fluid feeding gear are connected to the suction port. A suction-side lubrication groove that communicates with the discharge-side lubrication groove whose outer end communicates with the discharge port is formed.By increasing the inner diameter of the bearing on the gear body side, an annular lubricating oil inlet is formed. In a gear pump in which the inner ends of the lubricating grooves communicate with the lubricating oil inlet, backflow prevention is performed inside the lubricating oil inlet to prevent the flow of fluid from the discharge-side lubricating groove toward the suction-side lubricating groove. The point is that members are provided.

[0010]

[Action]

 According to the structure of the present invention, the flow of the fluid from the discharge side lubricating groove to the suction side lubricating groove is blocked by the blocking member provided inside the lubricating oil introducing port.

[0011]

【Example】

 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 resin liquid having high viscosity extruded from a screw extruder, and the resin liquid fed out is solidified and formed into a sheet by a molding machine. It is taken up and wound up. The gear pump 1 includes a housing 2 and a pair of fluid feeding gears 3 and 4 that mesh with each other in the housing 2.

The housing 2 has a tubular main body 5, a front cover 7 attached to one end of the main body 5 with a bolt 6, and a rear cover 9 attached to the other end of the main body 5 with a bolt 8. I have it. The main body 5 is formed with a fluid inlet 10a and a fluid outlet 10b. The housing 2 is covered with a heater (not shown) for heating the fluid.

One gear 3 is on the drive side and is provided with a drive gear main body 11 having teeth formed on the outer periphery thereof and a drive shaft portion 12 extending from the drive gear main body 11 in both axial directions. The drive shaft portion 12 is supported by an inner peripheral surface 14 a of a cylindrical bearing 14.

The other gear 4 is on the driven side and is provided with a driven gear body 16 having teeth formed on the outer periphery thereof, and a driven shaft portion 17 projecting from the driven gear body 16 in both axial directions. The driven shaft portion 17 is supported by the inner peripheral surface 14 a of the cylindrical bearing 14.

The space surrounded by the outer peripheral surfaces of the teeth of the drive gear body 11, the outer peripheral surfaces of the teeth of the driven gear body 16, the inner peripheral surface of the housing body 5, and the bearing 14 forms a fluid feed passage. As the drive gear 3 is rotationally driven in the direction of the arrow shown in FIG. 1, the fluid is sucked from the suction port 10a and discharged from the discharge port 10b through the fluid feed passage.

Each drive shaft portion 12 is projected to the outside of the housing 2, and the drive shaft portion 12 protruding from the front cover 7 side is connected to an unillustrated drive source.

A labyrinth seal 30 that restricts the outflow of fluid from between the outer periphery of each drive shaft portion 12 and the housing 2 is formed. That is, the first tubular member 31 is fitted on the outer periphery of the drive shaft portion 12 protruding from the housing 2, and the second tubular member 32 that covers the first tubular member 31 is attached to the housing 2 with the bolt 33, and the first tubular member 31 is attached. 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 tubular member 32, and an inlet 35 for the cooling medium and an outlet 36 for the cooling medium are formed in the passage 34. As a result, the amount of outflow of the fluid can be adjusted by adjusting the viscosity of the fluid that flows out between the housing 2 and the outer periphery of the drive shaft portion 12 by the cooling medium.

As shown in FIGS. 3 and 4, the gear body side of the inner peripheral surface 14 a of each bearing 14 has a tapered portion T subjected to crowning and a chamfered portion C subjected to chamfering. ing. As a result, the inner diameter of each bearing 14 is increased on the gear body side, and an annular lubricating oil introduction port 15 is formed.

Further, since a minute gap between the side surface of each bearing 14 and the gear bodies 11 and 16 is lubricated by the feed fluid, the side surfaces of the bearing 14 facing the gear bodies 11 and 16 are respectively provided. Three lubricating grooves 25, 26, 27 are formed. In each bearing 14, the first lubrication groove 25 has an outer end communicating with the suction port 10 a and an inner end serving as a suction side lubrication groove communicating with the lubricating oil inlet 15. The second lubricating groove 26 has an outer end communicating with the discharge outlet 10b and an inner end communicating with the lubricating oil inlet 15 and is a discharge side lubricating groove. An outer end of the third lubrication groove 27 communicates with the fluid feed passage between the suction port 10a and the discharge port 10b, and an inner end communicates with the lubricating oil introduction port 15. As shown in FIGS. 3 and 4, a lubricating groove 28 is formed along the axial direction in each bearing inner peripheral surface 14a so as to communicate with the inner end of the third lubricating groove 27.

Then, the flow of the fluid that flows back into the suction port 10a from the discharge port 10b through the discharge side lubrication groove 26, the lubrication oil introduction port 15 and the suction side lubrication groove 25 is blocked inside each of the lubricating oil introduction ports 15. A backflow prevention member 41 is provided. In this embodiment, the backflow prevention member 41 is located in front of the inner end of the discharge-side lubrication groove 26 in the rotation direction of the gears 3 and 4 (in the direction of the arrow in FIG. 1) and from the inner end of the suction-side lubrication groove 25. Is also arranged behind the gears 3 and 4 in the direction of rotation. It should be noted that the lubricating oil introduction port is located behind the inner ends of the discharge-side lubrication grooves 26 in the rotational direction of the gears 3, 4 and between the inner ends of the intake-side lubrication grooves 25 and in the front in the rotational direction of the gears 3, 4. A backflow of the fluid from the discharge port 10b to the suction port 10a also occurs by passing through 15. However, the circumferential distance of the lubricating oil introduction port 15 is long between them, and the fluid is discharged by the rotation of the gears 3 and 4. Since the reverse flow from the inlet to the suction port 10a is prevented, the reverse flow rate of the fluid is small, and the necessity of providing the reverse flow blocking member is small.

In the present embodiment, the blocking member 41 is integrated with the bearing 14 by partially not providing the tapered portion T by the crowning process and by partially reducing the chamfered dimension of the chamfered portion C. It is provided in. It is not necessary to completely close the lubricating oil introduction port 15 by the backflow blocking member 41, and it is sufficient if the backflow of the fluid can be blocked to reduce the backflow rate.

According to the gear pump 1 having the above-described configuration, the lubrication grooves 25, 26, 27 provided on the side surfaces of each bearing 14 and the lubrication groove 28 formed on the inner peripheral surface of the bearing 14 allow the gear bodies 11, 16 and the bearings to be engaged. 14, the feed fluid is introduced as a lubricating fluid between the outer peripheral surfaces of the shaft portions 12 and 17 and the inner peripheral surface 14a of the bearing 14 to prevent galling and seizure between the gears 3 and 4 and the bearing 14. To be prevented.

The backflow blocking member 41 formed at the lubricating oil inlet 15 blocks backflow of fluid from the outlet 10b to the inlet 10a through the lubricating grooves 25 and 26, thereby improving volumetric efficiency. In addition, the propagation of pressure from the suction side to the discharge side also becomes small, and the pressure fluctuation of the discharged fluid becomes small.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the backflow prevention member 41 is provided integrally with the bearing 14. However, as shown in FIG. It may be used as a backflow prevention member by press fitting into 45 and fixing. Further, although the lubricating oil inlet 15 is provided by the crowning process and the chamfering process in the above embodiment, it may be formed only by providing the curved chamfered portion C ′ by the chamfering process as shown in FIG. 5, for example. In short, the lubricating oil introduction port may be formed by increasing the inner diameter of the bearing 14 on the gear body side. Further, in the above-mentioned embodiment, the boundary between the gear bodies 11 and 16 and the shaft portions 12 and 17 is the curved surface R, but as shown in FIG. Therefore, the circumferential groove 50 may be provided, and a part of the backflow preventing member 41 ′ may be inserted into the circumferential groove 50.

[0026]

[Effect of the device]

 According to the gear pump of the present invention, by providing the backflow prevention member inside the lubricating oil introduction port formed in the bearing, it is possible to prevent the backflow of the fluid from the discharge port to the suction port and improve the volumetric efficiency. Fluctuations in fluid pressure on the discharge side can be reduced.

[Brief description of drawings]

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

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

FIG. 3 is a front view of a bearing according to an embodiment of the present invention.

FIG. 4 is a vertical sectional view of a bearing according to an embodiment of the present invention.

FIG. 5 is a vertical sectional view of a bearing according to another embodiment of the present invention.

FIG. 6 is an operation explanatory view of a conventional example.

FIG. 7 is an explanatory view of the operation of a conventional example.

[Explanation of symbols]

 1 Gear Pump 3, 4 Gear 10a Suction Port 10b Discharge Port 12, 17 Shaft 14 Bearing 15 Lubricating Oil Inlet 25 Suction Side Lubrication Groove 26 Discharge Side Lubrication Groove 41, 41 'Backflow Prevention Member

Claims (1)

[Scope of utility model registration request] 1. A suction-side lubrication in which a shaft portion of a pair of fluid feed gears is supported by an inner peripheral surface of a bearing, and an outer end communicates with a suction port on a side surface of the bearing facing a body of the fluid feed gear. A groove and a discharge-side lubricating groove whose outer end communicates with the discharge port are formed, and the inner diameter of the bearing is increased on the gear body side to form an annular lubricating oil introduction port. In the gear pump in which the inner ends of the respective lubrication grooves are communicated with each other, a backflow prevention member that prevents a fluid flow from the discharge-side lubrication groove toward the suction-side lubrication groove is provided inside the lubrication oil introduction port. Gear pump characterized by.