JPH0744783Y2 - Gear pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a gear pump suitable as a pump for pumping a high-viscosity fluid such as a polymer.

(Prior Art) A gear pump is widely used as a pump that sucks a high-viscosity fluid such as a high-molecular polymer from a reaction tank and pressure-feeds it. This gear pump rotatably internally supports a first-order gear fitted in a gear case and a gear shaft of each gear, and a total of four bearings whose end faces are in sliding contact with the corresponding side faces of the gear. And is usually attached to the bottom outer wall of the above-mentioned reaction vessel. Then, the high-viscosity fluid that flows in from the suction port that opens at the top of the gear case is sucked in and is pumped to the discharge port side.

In recent years, high-molecular-weight polymers that this type of gear pump attempts to pump are appearing, and when these high-molecular polymers are pumped by a gear pump, the fluid has a high viscosity and the reaction tank Has only a small liquid head,
Further, the inside of the tank is often a vacuum, and therefore, the amount of the liquid that reaches the gear portion of the gear pump from the reaction tank is determined approximately by the free fall amount of the liquid with respect to the shape of the suction port of the gear pump. Therefore, as a gear pump of this type for pumping a highly viscous liquid, one having an intake port of a shape as large as possible so as to satisfy the specifications is used.

In order to form the intake port with the largest possible size,
The suction port of the conventional gear pump has a circular shape at the upper opening of the flange portion and a substantially rectangular shape at the gear opening, and has a passage shape in which the upper opening and the gear opening are smoothly connected. The width of the rectangular shape in the gear portion opening is equal to the gear width, the length is substantially equal to the sum of the pitch circle diameter of the pair of gears and the gear outer diameter, and is substantially equal to the opening diameter of the upper opening.

(Problems to be solved by the invention) As described above, the conventional gear pump has the rectangular suction port at the gear opening, and the passage resistance of the liquid in this rectangular shape is greatly affected by the width dimension. In order to reduce the passage resistance of the liquid, it is necessary to set the gear width as large as possible as the design allows. However, if the gear width is set to be large, another problem that is not preferable in design, such as the bearing surface pressure exceeding the allowable value, occurs, and it is not possible to simply increase the gear width. Therefore, it has been necessary to select a gear pump having a gear with large gear specifications, that is, a gear pump having a large outer shape in order to satisfy the usage values such as the discharge flow rate.

The present invention has been made to solve such a problem, and it is suitable for pumping a high-viscosity liquid by enhancing the suction performance without increasing the gear width, that is, without changing the outer shape of the gear pump. The purpose is to provide a gear pump.

(Means for Solving the Problems) According to the present invention in order to achieve the above-mentioned object, according to the present invention, each gear shaft of a pair of gears is rotatably internally supported and each end face is a side surface of the gear. In a gear pump having a bearing that slides in contact with the gear, and the suction port is arranged vertically above the gear shaft of the gear, the groove bottom radius is the root of the gear at the peripheral edge of the end face of each bearing facing the suction port. The sum of the groove lengths that connect the groove end faces of two bearings that are substantially equal to the radius and are adjacent to each other with a straight line is the length between the outermost ends of the pair of gears (that is, the pitch circle diameter of the gears and the outside of the gears). A groove substantially equal to the sum of the diameters) is formed, and the shape of the opening of the gear portion of the suction port is formed in a rectangular shape that is expanded from the tooth width of the gear by the groove width on both sides of the gear. Gear pumps are provided.

(Operation) A groove having a shape defined by the present invention is provided on the peripheral edge of the bearing, which is in contact with the side surface of the gear and faces the suction port, and the shape of the opening of the gear portion of the suction port is set so that the width of the gear is smaller than the tooth width of the gear. By forming a rectangular shape that expands on both sides,
The amount of liquid that freely falls from the suction port increases, and the suction performance of the gear pump can be improved.

(Embodiment) An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 4 show a gear pump according to the present invention. The gear pump 1 includes a pair of driving gears 10, a driven gear 11,
A gear case 12 in which these gears 10 and 11 are fitted, and each gear 1
The gear shafts 10a and 11a of 0 and 11 are pivotally supported, and the bearings 13 to 16 fitted in the gear case 12 are configured.

The gear case 12 has a substantially rectangular parallelepiped shape, and has an upper surface formed with a mounting flange 12a for mounting the gear pump 1 in a reaction tank (not shown) and a mounting boss 12i connected with a transfer pipe (not shown) on the lower surface. There is.
The gear case 12 has two through holes 12d and 12e penetrating from one side wall 12b to the other side wall 12c and into which the drive gear 10 and the driven gear 11 are fitted, and their central axes are separated from each other by a predetermined distance (described later). Distance between drive gear 10 and driven gear 11 (distance corresponding to pitch circle diameter of drive gear 10 and driven gear 11 described later)
It is bored in the horizontal direction with a space between them. These through holes 12d and 12e are overlapped with each other over the entire area in the axial direction to form a cocoon-shaped cross section. At this time, the sum of the distances between the intersections where the straight lines passing through the centers of the through holes 12d and 12e intersect the through holes 12d and 12e is equal to the sum of the pitch circle diameters of the gears 10 and 11 and the gear outer diameters. The through holes 12d and 12e are provided with an intake port 12f upward at a substantially central position in the axial direction of a portion where these are overlapped with each other.
It communicates with the discharge port 12g below.

The drive gear 10 passes through the center axis of the drive gear 10 (gear shaft (drive shaft)).
10a extends from the side surface to both sides, and the gear shaft 10a is rotatably rotatably in the center hole 16a of the bearing 16 on one side wall 12b side and the center hole 15a of the bearing 15 on the other side wall 12c side with the drive gear 10 interposed therebetween. In addition, the respective end surfaces of the bearings 16 and 15 are slidably in contact with the corresponding side surfaces of the drive gear 10 and are axially supported, and the bearings 15 and 16 and the drive gear 10 are fitted in the through hole 12e in the assembled state. Has been done.
The gear shaft 10a on the side of the other side wall 12c has substantially the same length as the bearing 15, and the gear shaft 10a on the side of the side wall 12b penetrates not only the center hole 16a of the bearing 16 but also a front cover 18 described later to the outside. The drive pulley of a drive device (not shown) is mounted on the projecting end.

A gear shaft 11a extends from the side surface to both sides of the driven gear 11 so as to penetrate through the center shaft thereof. The gear shaft 11a sandwiches the driven gear 11 and one side wall 12b side thereof has a center hole (not shown) of the bearing 14 on the side wall 12b side. To
The other side wall 12c side is rotatably mounted in the center hole 13a (see FIG. 3) of the bearing 13 and each end face of the bearing is slidably brought into contact with the corresponding side face of the driven gear 11 so as to be axially supported. Bearing 13,14
The driven gear 11 is fitted into the through hole 12d in the assembled state, and the driven gear 11 meshes with the drive gear 10.
The gear shaft 11a extending on both sides of the driven gear 11 has substantially the same length as the bearings 13 and 14 on either side. Further, the drive gear 10 and the driven gear 11 described above are formed in the same gear shape.

The openings of the through holes 12d and 12e on the side wall 12c side are the rear cover 17
The cover 17 is liquid-tightly screwed to the gear case 12. Each opening of the through holes 12d and 12e on the side wall 12b side is closed by a front cover 18, and the cover 18 is screwed to the gear case 12 in a liquid-tight manner. The front cover 18 has a cylindrical seal member holding portion 18a from which the drive-side gear shaft 10a projects.
Is formed so as to project outward, and the space between the inner peripheral wall of the seal member holding portion 18a and the gear shaft 10a is liquid-tightly held by a seal member 19 such as a gland packing or a mechanical seal.

Four bearings 13 according to the present invention that support the gear shafts 10a and 11a.
1 to 16, a notch 1 is formed along the peripheral edge of the end surface of each bearing 13 to 16 that is in sliding contact with the corresponding gear 10 or 11, facing the suction port 12f.
2b to 16b are formed (see FIGS. 1 and 4).
These cutouts 13d to 16d are formed on the bearings 13 to 16 and the gears as described later.
When the gears 10 and 11 are assembled, the grooves 20 and 21 are formed by the side faces of the gears 10 and 11 (see FIG. 2). The notch width G (see FIG. 4) of each notch 13b to 16b varies depending on the number of gear modules, but is 0.2 to 5 of the gear height of the gears 10 and 11.
It is desirable to set double. Groove width is realistically 10 to 20 mm
The degree. If it is smaller than 10 mm, the effect is small, 20
If it is larger than mm, retention of liquid occurs. On the other hand, the tooth height is in the range of about 5 to 40 mm. Therefore, the groove width is about 0.2 to 5 times the tooth height. Further, the notch depth (groove depth) from the outer peripheral surface of the bearings 13 to 16 is such that the groove bottom radius R after assembly is the gear 1
It is optimal to set it to be equal to the root radius of 0,11. When the radius is larger than the root radius, the effect decreases as the radius increases, and when the radius is smaller, the effect beyond the optimum diameter cannot be expected. Further, the cutout length is the sum L of the cutout lengths (correctly, the linear distance between the groove ends) of two bearings (bearings 13 and 15 and bearings 14 and 16) adjacent to each other, and the pitch circle diameter of the gears 10 and 11. Is set to be approximately equal to the sum of the gear outer diameter.

The suction port 12f opens in a circular shape on the upper surface of the gear case 12, and the center of this upper opening coincides with the center of the flange 12a. The gear portion opening communicating with the gears 10 and 11 of the suction port 12f has a substantially rectangular shape, and the width thereof is the gears 10 and 1.
The notch width of the above-mentioned notches 13b to 16b is 2G larger than the gear width 1 of 1 (l + 2G), and the length is the notch length of the above-mentioned two adjacent bearings (bearings 13 and 15 and bearings 14 and 16) ( However, the length L is substantially equal to the sum L of the linear distances, and the length L is equal to the diameter of the upper opening. The suction port 12f has a passage shape in which the upper opening and the gear opening are smoothly connected.

Incidentally, the inner wall of the gear case 12 communicates with the gear portion opening of the suction port 12f described above along the gear width direction of the gears 10 and 11, and the groove bottom passes through the centers of the gears 10 and 11. Grooves 12j and 12k that contact the through holes 12d and 12e, respectively, are formed near the points where the straight lines intersect the through holes 12d and 12e. The discharge port 12g has a circular cross section, and is formed in the center of the lower surface of the gear case 12 concentrically with the boss 12i.

Next, the operation of the gear pump 1 configured as described above will be described.

When the gear shaft 10a is rotationally driven by the drive device, the drive gear 10 and the driven gear 11 rotate in the direction shown in FIG. The high-viscosity liquid flowing in from a reaction tank (not shown) by substantially free fall is guided from the upper opening of the suction port 12f to the gear opening. At this time, the fluid that has fallen between the tooth grooves of the gears 10 and 11 is filled, but the tooth grooves near the side walls of the gears 10 and 11 are formed with the notches 13a to 16a formed in the bearings 13 to 16 and the gears.
The grooves 20 and 21 defined by the side surfaces of 10 and 11 are filled with the dropped liquid. Further, the liquid introduced into the grooves 12j and 12k formed on the inner wall of the gear case 12 is pushed into the tooth space by the rotation of the gears 10 and 11, and the space formed in the tooth space is filled with the liquid. Thus, the suction performance of the gear pump is improved, the liquid filled in the tooth space is pressure-fed to the discharge port 12g side, and is further discharged to the transfer pipe (not shown).

In the present invention, each bearing 13-16 is provided with notches 13a-16a.
Grooves are formed between the side surfaces of the gears 13 to 16 and the gears 10 and 11, but the shape of the suction port is formed without forming the groove from the conventional shape shown by phantom line 12f 'in FIG. 2 to the shape of the present invention 12f. If the gear portion opening is extended to both sides of the gears 10 and 11 by the notch width G as in the present invention, the outer circumference of the bearings 13 to 16 exposed at the gear portion opening of the intake port 12f is changed to A liquid pool is generated, and no particular effect can be obtained on the inflow of liquid into the tooth spaces of the gears 10 and 11.

The present invention is characterized in that the peripheral edges of the bearings 13 to 16 which are in sliding contact with the gears 10 and 11 facing the suction port 12f are notched so that the liquid flows from the side surfaces of the gears 10 and 11 into the tooth spaces. ,
The cutout shapes of the bearings 13 to 16 are not particularly limited as long as the liquid is allowed to flow into the tooth spaces from the side surfaces of the gears 10 and 11 in this manner, and in the present invention, the cutouts 13a to 16a have substantially the same sectional shape. Although it has a rectangular shape, it may have a sectoral cross-section with a corner R between the groove bottom and the side wall.

(Effect of the Invention) As described in detail above, according to the gear pump of the present invention, the radius of the groove bottom is substantially equal to the radius of the tooth bottom of the gear at the peripheral edge facing the suction port of the end surface slidingly contacting the side surface of the gear of each bearing. And a sum of distances between groove ends of two bearings adjacent to each other is substantially equal to a length between outermost ends of the pair of gears,
Since the shape of the opening of the gear portion of the suction port is formed in a rectangular shape that is expanded from the tooth width of the gear by the groove width on both sides of the gear, it is possible to increase the amount of liquid that freely falls from the suction port. The suction performance can be improved without increasing the size, that is, without changing the outer shape of the gear pump. Therefore, the gear pump can be downsized as compared with the conventional gear pump having the same performance.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a top view of a gear pump according to the present invention, FIG. 2 is a sectional view taken along the line II--II of FIG. 1, and FIG. 3 is III of FIG. FIG. 4 is an enlarged perspective view of the bearings 13 and 14, which is a sectional view taken along line III-III. 1 ... Gear pump, 10 ... Drive gear, 10a ... Gear shaft, 1
1 …… Driven gear, 11a …… Gear shaft, 12 …… Gear case, 12
f …… Suction port, 12g …… Discharge port, 13-16 …… Bearing, 13a-16a …… Notch, 20,21 …… Groove.

Claims (1)

[Scope of utility model registration request] 1. A suction port is provided vertically above the gear shaft of each of the pair of gears, and includes a bearing that rotatably and internally supports each gear shaft, and each end face of which is in sliding contact with a side face of the gear. In the gear pump in which the groove bottom radius is substantially equal to the root radius of the gear, the groove end faces of the two bearings adjacent to each other are linearly formed on the peripheral edge of the end face of each bearing facing the suction port. A groove whose sum of groove lengths is substantially equal to the sum of the pitch circle diameter of the gear and the gear outer diameter, and the shape of the suction port opening at the gear portion is set to be a gear width greater than the tooth width of the gear by the groove width. A gear pump characterized by being formed in a rectangular shape that is expanded on both sides of the gear pump.