JP3239026B2 - 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 conveying a liquid. More specifically, the present invention relates to a gear pump having a relief groove for conveying water.

[0002]

2. Description of the Related Art Conventionally, there is known a gear pump configured to pump a fluid by meshing and rotating a pair of gears. This gear pump is adapted to, for example, an automatic ice making device of a refrigerator.

FIG. 4 is a view for explaining a change in volume of a closed portion of a gear pump and an effect of an escape groove for relieving the change in volume. First, according to FIG. 4 (d), the is closed portion 3 occurs when the gear 2, 2 a pair of slide and rotate the casing 1 inside surface meshes, the closed portion 3 in the rotation of the gear 2, 2 The liquid that moves with it and is closed in the closing section 3 is conveyed.
4A shows the closing start point, FIG. 4C shows the closing end point, and FIG. 4B shows the intermediate state. This closing is caused by the contact movement of the contact points A and B of the teeth.
As a result, the volume v of the closed portion 3, as shown in FIG. 5,
The confinement decreases gradually in the period from the start to the intermediate confinement, minimum v _min becomes an intermediate position confinement, gradually increases past the same. That is, there is a change in the volume due to the rotation.

[0004] Liquid such as water or oil does not expand or contract under pressure or decompression, so that when the volume of the confined portion 3 of the gear pump is reduced, the pressure becomes extremely high and passes through a confined intermediate position. Conversely, when the volume of the confinement section 3 increases, a vacuum state is established. Therefore, when the confined volume decreases,
When the shaft power and the bearing load increase, while the confined volume increases and a vacuum state is established, the vapor pressure of the gas dissolved in the liquid apparently decreases and approaches the boiling state to generate bubbles. With the rotation of the gear, the pressure fluctuation of the closing portion 3 occurs intermittently, so that the gear vibrates and not only emits noise with the vibration, but also pulsates the discharge pressure irregularly,
This will shorten the pump life.

[0005] As one of the methods for preventing this volume fluctuation,
There is a method of providing a relief groove for releasing the volume fluctuation of the closing portion 3 in the pump case portion on the side surface of the gear. That is, FIG.
Shown in a position corresponding to the section in which the volume of the closed portion 3 is reduced, by providing the relief groove 4 to release the liquid in the closed portion 3, if communication with the groove 4 escapes closed portion 3 When the confined volume decreases, the excess volume Δv ₁
To the discharge side through which no abnormal pressure rise occurs. Past the intermediate state, if the volume of the closed portion 3 began to increase, of the closed portion 3 of the confinement if Sasere communication with the suction side by another of the escape groove 5 expansion Sai lack volume △
v ₂ does not generate vacuum is supplied from the suction side.

[0006] This method is well-known, but the conventional relief groove
Reference numerals 4 and 5 denote rectangular cases, each of which is a line perpendicular to the center line of the meshing of the two gears 2 and 2 and which is close to a pair of gear central axes as one side and faces toward the discharge port 6 and the suction port 7. Grooves were dug down to the side surfaces at the same depth to form escape grooves 4,5. In this method, the liquid in the confining portion 3 certainly moves to the discharge side or the suction side through the escape grooves 4 and 5, and the excess volume Δv ₁
And the fluctuation of the variable volume Δv constituting the insufficient volume Δv ₂ can be reduced. If left in a state where residual water has accumulated, not only corrosion will occur inside the case including this groove, but also
At the next use, water containing red rust will be discharged. Also,
Deterioration of the residual water itself (such as propagation of various germs) occurs, and the water inhaled after the restart is contaminated.

[0007]

In view of the above situation, the present invention makes it difficult for the residual water to collect by changing the shape of the groove and the depth of the groove. It is intended to prevent the water from deteriorating.

[0008]

According to a first aspect of the present invention, there is provided a gear pump comprising two gears meshing with each other and a case surrounding the gears. In a gear pump in which a relief groove for a liquid to be pumped is formed, a cross-sectional area of the relief groove extending in a direction perpendicular to an imaginary plane including a central axis of the two gears and cut along a plane parallel to the imaginary plane. From the virtual plane
Gradually reduce as you walk, and the relief groove,
Liquid confinement formed by the contact of two gears
Tooth forming the closed part from a position where it can come into contact with
Extending to the position where the teeth adjacent to
You.

A gear pump according to a second aspect of the present invention includes two gears that mesh with each other and a case that surrounds the gears, and a relief groove for the liquid to be pumped is formed in a wall of the case that faces a side surface of the two gears. In the gear pump, the aforementioned 2
Perpendicular to an imaginary plane containing the center axis of one gear pump
In a plane parallel to the virtual plane of the escape groove extending in the direction
The cut cross-sectional area is formed such that the side closer to the virtual surface is larger and the side farther from the virtual surface is smaller, the bottom of the clearance groove is formed in a tapered shape, and the bottom closer to the virtual surface is formed deeper. It was done. According to a third aspect of the present invention, the relief groove is formed in a substantially triangular shape, and a side closer to the virtual surface is a bottom side of the substantially triangular shape.

A gear pump according to a fourth aspect of the present invention includes two gears that mesh with each other and a case that surrounds the gears, and a relief groove for the liquid to be pumped is formed in a wall of the case that faces the side surfaces of the two gears. In the gear pump, the aforementioned 2
The cross-sectional area of the relief groove extending in a direction perpendicular to the virtual plane including the central axis of the two gear pumps, taken along a plane parallel to the virtual plane, is set such that the side closer to the virtual plane is larger and the virtual plane is larger. The side far from is formed small , and the escape groove,
Confinement of the liquid formed by the contact of the two gears
The closed part is formed from a position where it can
Extending to the position where the teeth adjacent to the teeth exist.

[0011]

The depth or volume of the relief groove dug in the case is increased or decreased near the two center axes of the gear in a direction perpendicular to the two meshing center lines of the gear, on the discharge side or the suction side. By making the depth shallower or smaller gradually, the residual water can be made harder to collect while maintaining the effect of the escape groove. As a result, it is possible to make it difficult to corrode the inside of the case including the groove or to make the water hardly deteriorate.

[0012]

FIG. 1A is a plan view of at least one case constituting a gear pump according to the present invention, and FIG. 1B is a plan view in which a pair of gears are mounted on the above-mentioned plan view. FIG. Members having the same functions and effects as those in FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 1, reference numeral 8 denotes a meshing center line formed when a pair of gears mesh with each other, and reference numeral 9 denotes a center axis connecting the centers of the pair of gears. A direction perpendicular to the paper surface of a center line formed by the central axis 9 is defined as a virtual surface 16. 12, 13
Are the end surfaces 1 and 11 with the direction close to the virtual surface 16 as the end surfaces 10 and 11.
It is a relief groove dug in the case surface from 0, 11 and further toward the discharge side 14 and the suction side 15 with the meshing center line 8 as the axis of symmetry. The relief grooves 12, 13 are dug deep at the end faces 10, 11 as shown in section AA, and
4 and the suction side 15.

The volume of the escape grooves 12 , 13 is increased on the end faces 10, 11 near the imaginary surface 16, and is gradually reduced as the distance from the imaginary surface 16 increases.
As the distance increases, the volume of the remaining water decreases. This means that residual water is less likely to accumulate, and as a result, it is possible to make it difficult to corrode the inside of the case including the escape grooves 12 and 13 or to make the water hardly deteriorate.

Here, it is assumed that the end face takes various positions. In FIG. 2, which is contrasted with FIG. 4, the closing start position is shown in FIG. It is the range of p shown in the figure corresponding to the area of the discharge, and almost no effect is obtained on the discharge side. In addition, the closed middle position diagram 2
In (b), the end face of the escaping groove formed from the virtual surface is at the limit of the vertical position of the meshing center line formed by the contact points A and B of the mutual teeth, P and Q shown in FIG. No confining portion is formed and the function as a pump is lost. Therefore, the position of the end face forming the clearance groove is important and is arbitrarily set within a range where the clearance groove effect is present. In contrast, FIG.
As described in (a), since there is almost no effect on the suction side and the discharge side, even if the volume formed by the relief groove decreases as the meshing center line 8 moves away from the end face of the relief groove, the effect of the relief groove can be obtained. Does not mitigate.

This means that, in addition to the rectangular shape shown in the conventional example, the escape groove can have various shapes in which the meshing center line is reduced in a direction away from the end face of the escape groove. FIG. 3 shows this example, and can take various shapes shown in FIGS. 3 (a), 3 (b), 3 (c) and 3 (d). In addition to this, as described above, the shape does not need to include only straight lines or curves as long as the shape is reduced in a direction away from the end face of the clearance groove. Further, in addition to the same cross-section that is dug down from the known case surface shown in FIG. 3 (e), the cross-section also has a taper that gradually becomes shallower from the end face toward the suction side or the discharge side as shown in FIG. 3 (f). Can be adopted. These are to reduce the residual water while maintaining the effect of the escape groove as described above.

Also, the drainage of the water at the water confined portion by the gear is facilitated by forming the escape groove with a larger volume on the side closer to the virtual surface and a smaller volume on the side farther from the virtual surface. Also, when viewed from the virtual surface 16, the closed portion 3 and the escape groove on the side closer to the virtual surface overlap, and the deeper the escape groove in the overlapped portion is, the easier the drainage of water is. .

The gear amplifier according to the present invention can be used not only for pumping water but also for transferring other liquid substances. For example,
It can also be used to transport emulsions and liquid sludge mixed with water and oil, and in this case, it can also effectively reduce corrosion.

[0019]

As described above, according to the present invention, it is possible to reduce the residual water of the escape groove as compared with the conventional escape groove. In addition, it is possible to eliminate the volume fluctuation of the closing portion. As a result, the gear pump is intended high economic efficiency in can stably used for a long time not only does not emit noise.

[Brief description of the drawings]

FIG. 1A is an embodiment of a plan view of the inside of a case constituting a gear pump according to the present invention, and FIG. 1B is a view in which a pair of gears are mounted on the inner plan view.

FIG. 2 is a diagram showing a relationship between an end face and the start of closing.

FIG. 3 is a view showing the shape of another escape groove according to the present invention.

FIG. 4 is a view for explaining the reason for providing an escape groove for closing the gear pump and escaping a pressure change thereof.

FIG. 5 is a diagram showing a change in volume of a closed portion.

[Explanation of symbols]

 3 closing part 10 end face 11 end face 12 relief groove 13 relief groove 14 discharge side 15 suction side 16 virtual surface

Claims (4)

(57) [Claims] 1. A gear pump comprising two gears meshing with each other and a case surrounding the gears, wherein a relief groove for a liquid to be pumped is formed on a wall of the case facing a side surface of the two gears. The cross-sectional area of the relief groove extending in a direction perpendicular to the virtual plane including the central axis of the two gears, which is cut by a plane parallel to the virtual plane, is gradually reduced as the distance from the virtual plane increases, and Wherein the relief groove extends from a position where it can come into contact with a liquid confinement formed by the contact of the two gears to a position where teeth adjacent to the teeth forming the confinement exist. Characterized gear pump. Two gears wherein meshing consists of a casing which surrounds these gears, the said two gear pump to form a relief groove of the liquid pumped into the wall of the casing to the side surface facing the gear, the 2 The center axes of the two gear pumps
Said relief extending perpendicular to the included virtual plane
The cross-sectional area of the groove cut by a plane parallel to the virtual surface is formed such that the side closer to the virtual surface is larger and the side farther from the virtual surface is smaller, and the bottom of the clearance groove is formed in a tapered shape, A gear pump, wherein the bottom portion on the side close to the surface is formed deep. 3. The gear pump according to claim 1, wherein the clearance groove is formed in a substantially triangular shape, and a side closer to the virtual plane is a bottom side of the substantially triangular shape. 4. A gear pump comprising two gears meshing with each other and a case surrounding the gears, wherein a relief groove for a liquid to be pressure-fed to a wall of the case facing a side surface of the two gears is formed. The cross-sectional area of the clearance groove extending in a direction parallel to the virtual surface with respect to the virtual surface including the central axes of the two gears is larger on the side closer to the virtual surface and the virtual surface is larger. And a tooth adjacent to the tooth forming the confining portion from a position where the escape groove can contact the liquid confining portion formed by the contact of the two gears. A gear pump characterized by being extended to a position where the gear pump moves.