JPS6345514B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technique for preventing noise from a gear pump or motor. (Since a gear pump and a gear motor have almost the same configuration, the gear pump will be described and the application of this invention to a gear motor will be described later.) Gears are housed in a casing, and when a driving force is applied to one of the gears, the gears mesh and rotate, thereby transporting fluid from the suction side to the discharge side. Therefore, the suction side and the discharge side are isolated by two gears and a casing (or a side plate may be used). In other words, the tooth tip surface of the gear and the casing fit together with a small gap, and the side surface of the gear and the casing or side plate (which may also serve as a bearing) are in rotatable contact, and there is no external contact. The teeth of the gear have a backlash and a meshing ratio such that the discharge side and the suction side are not communicated when the teeth rotate in mesh with each other. Therefore, if the gear is rotated with the entire side surface of the meshing part where the gear teeth mesh is sealed, the part closed by the seal part (hereinafter sometimes referred to as the "enclosed part") arise. In the confinement section, abnormal high pressure and low pressure are generated due to meshing rotation of the gears, and the gears vibrate due to the abnormal high pressure and low pressure, generating noise.

Below, Figures 1 and 2 show the meshing state of the gears.
Let's talk about the diagram. Figure 1 shows a drive gear g ₁ driven by a drive source such as an engine or a motor.
teeth 1g ₁ , 2g ₁ , 3g ₁ and tooth 1 of driven gear g ₂
This is a diagram showing one meshing state with g ₂ and 2g ₂ , which shifts to the meshing state shown in FIG. 2 as the drive side gear g ₁ rotates. When the drive side gear g ₁ and the driven side gear g ₂ rotate in a meshed state, fluid is conveyed from the suction side 1 to the discharge side 2. In FIG. 1 showing one meshing state during such driving,
Contact point k 1 between teeth 1g ₁ and 1g ₂ (hereinafter referred to as effective meshing point), contact point _{k 2 between} teeth 2g ₁ and 2g ₂ (hereinafter referred to as effective meshing point), and tooth 2g ₁ ,2g ₂
The figure s formed by the tooth profile curves 3 and 4 is a confinement part. (Hereinafter, the enclosing part will be expressed as a figure s.) This figure s shows the point of contact _k3 (hereinafter referred to as invalid meshing) when the driving gear _g1 and the driven gear _g2 are meshed without backlash. It is formed by a driving-side figure _s1 and a driven-side figure _s2 , which are divided by a point (denoted as a point). Although the figure s is divided at the point of ineffective engagement _k3 , it may be divided at the line of action R. In such meshing rotation,
The rate of decrease and increase in the area of figures s ₁ and s ₂ with respect to the rotation angle is firstly determined by the rate of decrease and increase in the area of figure s ₁ when the ineffective engagement point k ₃ is on the discharge side from the center line l _.
The difference in the rate of increase and decrease in the areas of shapes s ₁ and s ₂ becomes smaller as the point of ineffective engagement approaches the center line l, and the point of ineffective engagement k ₃ becomes closer to the suction side than the center line. shape as you move
The difference between the rate of decrease and rate of increase in area between s ₁ and s ₂ becomes larger. Therefore, the entire figure s has an invalid meshing point
When k ₃ is approaching the center line l from the discharge side, the pressure is abnormally high, and when the ineffective engagement point k ₃ is moving from the center line l to the suction side, the pressure is low. Therefore, the driven gear _g2 vibrates due to the action of these abnormally high and low pressures, which is one of the major causes of noise generation.

This invention connects the figures s ₁ and s ₂ that occur during meshing rotation of the gears to the discharge side until the rate of increase in the area of these figures with respect to the rotation angle is slightly larger than the rate of decrease, and also connects the figures with the figures. When the discharge side is cut off, this figure is connected to the suction side to prevent the generation of noise.

Below, FIGS. 3 and 4 show an embodiment of the present invention.
Let's talk about the diagram.

Figures 3 and 4 show the driving gear _g1 and the driven gear.
g ₂ are in the same meshing state as in Figures 1 and 2, and the figure shown by the two-dot chain line is the side plate or
The shapes of grooves 10 and 11 provided in the portions of the casing that seal the side surfaces of the driving gear g ₁ and the driven gear g ₂ are shown.

The groove 10 has a discharge groove 12 connected to the discharge side 2;
Grooves 13 and 14 (hereinafter referred to as
They will be referred to as a first small groove 13 and a second small groove 14. ). Further, the groove 11 includes a suction groove 15 connected to the suction side 2, and grooves 16 and 17 (hereinafter referred to as a third small groove 16 and a fourth small groove 17) connected to the suction groove 15. It is the composition.

The first small groove 13 of the groove 10 extends from the edge 18 of the drive side gear g ₁ of the groove 10 and has a tip 22 . This tip 22 is located between the line of action R and the tooth bottom h ₁ of the drive side gear g ₁ , and the shape s ₁ with respect to the rotation angle
The discharge side ₂ and the figure s ₁ are connected to a point where the increase rate is slightly larger than the decrease rate of the area of s 2 . (In other words, this is a state in which the ineffective meshing point _k3 moves a little toward the suction side, to the extent that no abnormally high pressure is generated in the figure _s1 .) The second small groove 14 of the groove 10
extends from the edge 19 of the groove 10 on the driven gear g ₂ side and has a tip 24 . This tip is located between the line of action R and the tooth bottom _h2 of the driven gear _g2 , and the figure _s2 continues until immediately before (or even simultaneously) the figure s1 and the discharge side ₂ are interrupted. and the discharge side 2 are connected to each other.

The third small groove 16 of the groove 11 has a tip 23 extending from the edge 20 of the groove 11 on the driven gear g ₂ side. This tip 23 is connected to the line of action R and the tooth bottom h ₂ of the driven gear g ₂
When the figure s ₁ and the discharge side 2 are cut off (or there may be a slight delay), the figure s ₂
It is designed to be connected to. The fourth small groove 17 of the groove 11 has a tip 25 extending from the edge 21 of the groove 11 on the drive side gear g ₁ side. This tip 25 is located between the line of action R and the bottom h ₁ of the drive side gear g ₁ , and when the figure s ₁ and the discharge side 2 are interrupted (or
It's okay to be a little late. ) is provided to connect to figure s ₁ .

Next, the operation of this embodiment will be described.

When the driving gear _g1 is rotated in the direction of arrow A by the driving force of the engine or motor, the driven gear _g2 meshed with the driving gear _g1 rotates in the direction of arrow B. The fluid on the suction side 1 is conveyed to the discharge side ₂ by the meshing rotation of the drive side gear g ₁ and the driven side gear g 2 .

During such operation, teeth 1g ₁ , 2g ₁ , 3g ₁ , and teeth 1g ₂ , ₂ of drive side gear g 1 , driven side gear g ₂
Immediately before the meshing state with g ₂ reaches the state shown in Figure 3, the effective meshing point k ₁ and the invalid meshing point k ₃
have a small gap and are engaged only at the effective engagement point _k2 . At this time, the figure formed by the meshing of the driving gear g ₁ and the driven gear g ₂
s′ ₁ and s ₂ ′ (not shown, but have almost the same shape as the shapes s ₂ and s ₁ in FIG. 3) are connected to the discharge side 12 via the second small groove 14, and these shapes This prevents abnormally high pressure from occurring in the s' ₁ and s' ₂ parts.

When the driving side gear g ₁ and the driven side gear g ₂ mesh and rotate and reach the state shown in Fig. 3, the teeth 1g ₁ , 2g ₁ , 3g ₁
The figures s ₁ and s ₂ formed by the meshing rotation of the teeth 1g ₂ and 2g ₂ are connected to the discharge groove 12 via the first and second small grooves 13 and 14.

When the meshing rotation starts to progress further from the meshing state shown in Fig. 3, the area of figure s ₁ decreases and the area of figure s ₂
increases, but as the area of figure _s1 decreases, part of the fluid in figure _s1 flows out into the discharge groove 12 through the first small groove 13, and the area of figure _s2 decreases. As the fluid increases, part of the fluid in the discharge groove 12 flows in through the second small groove 14.

In this way, when the meshing state shown in Figure 4 is reached, the rate of change in the area of shapes s ₁ and s ₂ with respect to the rotation angle becomes almost equal, and after this point the above-mentioned relationship becomes reversed. . However, the difference in the rate of change in the areas of the shapes s ₁ and s ₂ with respect to the rotation angle in the meshed state shown in FIG. 4 is relatively small. In this engaged state, part of the fluid in the figure _s1 flows out into the discharge groove 12 through the first small groove 13, and part of the fluid in the discharge groove 12 flows into the figure _s2 . (Note that the second small groove 13 may be arranged so that the figure _s2 and the discharge groove 12 are blocked in the meshing state shown in Figure 4.) As the rotation progresses further from Figure 4, the figure with respect to the rotation angle Immediately before the rate of increase in the area of figure _s2 starts to become larger than the rate of decrease in the area of _s1 , figure _s2 and discharge groove 1
2 is cut off (in addition, if you want to account for gear pump manufacturing errors, you may connect it slightly at this point). As the rotation progresses further, the area of figure s ₁ decreases due to the reduction rate of the area of figure s. When the rate of increase in the area of _s2 becomes a little large, the figure _s2 is cut off from the discharge groove 12. As the rotation progresses further from this situation, the figures s ₁ and s ₂ become the third and fourth small grooves 16 and 17.
opens, a part of the fluid in the figure _s1 flows out into the suction groove 15 through the fourth small groove 17, and in the figure _s2 ,
A portion of the fluid in the suction groove 15 flows through the third small groove 16 .

Although the embodiments in which the present invention is applied to an external gear pump have been described above, the present invention can be similarly applied to an internal gear pump, and the same applies to a gear motor. Although not shown in the embodiment applied to a gear motor, in FIG. 3, when high pressure fluid is supplied from the discharge side 2, the gear motor
g ₁ and g ₂ rotate in the direction opposite to arrows A and B. Therefore, the relationship of the confinement part (the relationship between s ₁ and s ₂ of the figure s)
is also reversed, and the shapes of the grooves 10 and 11 are different from the positions of the first small groove 13 and the second small groove 14 and the third small groove 1.
By changing the positions of the pump 6 and the fourth small groove 17, the same effect as that of a gear pump can be achieved.

As described above, the present invention provides a gear pump or a motor in which the confinement part is placed on the discharge side and on the suction side in the vicinity where the difference in the rate of change with respect to the rotation angle of the confinement part during meshing rotation of the gears is minimized. This prevents the generation of abnormally high or low pressures in the confinement section by connecting to the side, and has the effect of preventing the generation of noise caused by this.

[Brief explanation of drawings]

1 and 2 are diagrams showing the meshing state of gears, and FIGS. 3 and 4 are diagrams showing the relationship between the shape of the groove and the meshing state of the gears in this invention. 1... Suction side, 2... Discharge side, 3, 4... Gear curve, 10... Groove (discharge side), 11... Groove (suction side), 13... Groove (first small groove), 14 ... Groove (second small groove), 16... Groove (third small groove), 17...
Groove (fourth small groove), g ₁ ... Drive side gear, g ₂ ... Driven side gear, k ₁ , k ₂ ... Effective meshing point, k ₃ ... Ineffective meshing point, s ₁ ... Figure (closed) part), s ₁ , s ₂
...Figure, R...line of action, h ₁ , h ₂ ... tooth bottom.

Claims (1)

[Claims] 1 When the point of ineffective meshing between the driving gear and the driven gear is on the center line, there are two effective meshing points between the driving gear and the driven gear, and the tooth profile curve of the driving gear and the tooth profile curve of the driven gear. The shape to be formed on the side of the driving gear from the point of ineffective meshing should be adjusted so that the line of action and the bottom of the tooth of the driving gear do not generate abnormally high pressure when the point of ineffective meshing begins to move from the center line to the suction side. When the communication between this groove and the figure on the drive side gear side is cut off, the figure on the driven side gear side from the point of ineffective meshing is connected to the line of action and the tooth bottom of the driven side gear. a groove provided at a position connecting to the suction side between; the figure on the driven side gear side is cut off from the figure on the drive side gear side and the discharge side between the line of action and the tooth bottom of the driven side gear; A groove provided at a position that cuts off the discharge side immediately before or almost at the same time as it is cut off; When the communication between this groove and the figure on the driven side gear side is cut off, the figure on the drive side gear side is connected to the line of action. A gear pump or motor having a groove provided at a position connected to the suction side between the drive side gear and the tooth bottom of the drive side gear.