JPS6340948B2 - - 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 to transport 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 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 teeth 1g ₂ of driven gear g ₂ ,
FIG. 2 is a diagram showing one state of meshing with g ₂ , which shifts to the meshing state shown in FIG. 2 by rotation of the drive side gear g ₁ . When the driving gear g ₁ and the driven gear g ₂ rotate in mesh with each other, fluid is conveyed from the suction side 1 to the discharge side 2. In FIG. 1 showing one meshing state during such driving, tooth 1
The contact point K ₁ between g ₁ and 1g ₂ (hereinafter referred to as the effective meshing point) and the contact point K ₂ between teeth 2g ₁ and 2g ₂ (hereinafter referred to as the effective meshing point)
This is referred to as the effective engagement point. ) and the tooth profile curves 3 and 4 of the teeth _2g1 and _2g2 , the figure s is a confinement part. (Hereinafter, the enclosing part will be expressed as a figure S.) This figure S shows the contact point _K3 (hereinafter referred to as invalid meshing) when the driving side gear _g1 and the driven side gear _g2 are engaged with each other without backlash. Driving side figure S ₁ and driven side figure divided by point)
It is formed by S ₂ . Although the figure S is divided at the point of ineffective meshing _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 the decrease rate of the area of figure S ₁ when the ineffective engagement point K ₃ is on the discharge side from the center line l. is the shape S ₂
The difference in the rate of increase and decrease in area of figures S ₁ and S ₂ becomes smaller, and the point of ineffective engagement K ₃ moves toward the suction side from the center line. Accordingly, the difference between the decreasing rate and increasing rate of the areas of figures S ₁ and S ₂ becomes larger. Therefore, the entire figure S becomes abnormally high pressure when the ineffective meshing point K ₃ is approaching the center line l from the discharge side, and when the ineffective meshing point K ₃ is moving from the center line l towards the suction side. , resulting in low pressure. 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.

In this invention, the figures S ₁ and S ₂ that occur during meshing rotation of gears are adjusted until the rate of increase in the area of the figures with respect to the rotation angle becomes slightly larger than the rate of decrease in the area of the figure.
In addition to being connected to the discharge side, when the figure and the discharge side are cut off, this figure is connected to the suction side to prevent the generation of noise.

Below, Figures 3 and 4 show one embodiment of this 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 the 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 is configured to include a suction groove 15 connected to the suction side 2 and a groove 17 (hereinafter referred to as a third small groove 17) connected to the suction groove 15.

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 bottom h ₁ of the drive side gear g ₁ , and also has a shape S ₁ for the rotation angle.
The discharge groove 12 and the figure S ₁ are connected to each other up to a point where the increase rate is slightly larger than the decrease rate of the area of S ₂ . (In other words, it is a state in which the ineffective meshing point K ₃ moves a little toward the suction side, and an abnormally high pressure does not occur in the figure S _1. ) The second small groove 1 of the groove 10
4 has a tip 24 extending from the edge 19 of the groove 10 on the driven gear g ₂ side. This tip 24 is located between the line of action R and the bottom _h2 of the driven gear _g2 , and is
The figure S ₂ is connected to the discharge groove 12 until just before S ₁ and the discharge side 12 are cut off. Groove 1
The third small groove 17 has a tip 25 extending from the edge 21 of the groove 11 on the drive side gear _g1 side. This tip 25 is located between the line of action R and the tooth bottom h ₁ of the drive side wheel g ₁ , and the shape when the shape S ₁ and the discharge groove 12 are interrupted (or it may be delayed a little) It is provided to connect to _S1 .

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 diagram 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 second
are connected through small grooves 14 to prevent abnormally high pressure from occurring in the portions of the figures S' ₁ and S' ₂ .

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 figures 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 figures 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 .

As the rotation progresses further from Fig. 4, just before the rate of increase in the area of figure _S2 becomes greater than the rate of decrease in the area of figure _S1 with respect to the rotation angle, figure _S2 and discharge groove 1
(In addition, if you want to compensate for gear pump production errors, etc., it may be possible to connect slightly at this point.) As the rotation progresses further, the area of figure S ₁ decreases according to the area reduction rate. When the rate of increase in the area of ₂ becomes a little large, the figure _S1 is cut off from the discharge groove 12. As the rotation progresses further from this situation, the third small groove 17 of the figure S ₁ opens, and the figure S ₁
A part of the fluid in the figure S1 flows into the suction groove 15 through the third small groove 17, and a part of the fluid in the figure S1 flows into _{the figure S2 through} the backlash portion.

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. An example applied to a gear motor is not shown, but in FIG.
When high pressure fluid is supplied from the discharge side 2, the gear
g ₁ and g ₂ rotate in the direction opposite to arrows A and B. Therefore, the relationship between the confinement parts (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 position of 7, 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 sides, and has the effect of preventing the generation of noise caused by this.

[Brief explanation of the drawing]

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...Tooth profile curve,
10...Groove (discharge side), 11...Groove (suction side), 13...
Groove (first small groove), 14... Groove (second small groove), 17
...Groove (third 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 (enclosed 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 is set between the line of action and the bottom of the tooth of the driving gear to the extent that abnormal high pressure does not occur when the point of ineffective meshing begins to move toward the driving gear. A groove connected to the discharge side; When the communication between this groove and the figure on the drive side gear side is cut off, the figure on the drive side gear side is moved to the suction side between the line of action and the bottom of the tooth of the drive side gear. A groove provided at the connecting position; and a figure on the driven side gear side between the line of action and the tooth bottom of the driven side gear, and a groove on the discharge side immediately before the figure on the drive side gear side and the discharge side are cut off. A gear pump or motor that has a groove at a location where communication with the gear is cut off.