JPH063196Y2 - Gear pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a gear pump that prevents erosion from occurring and balances the loading force of a bush or a side plate.

(Prior Art) FIG. 5 shows a relationship between bushes 1 and 2 installed in a body a of a conventional gear pump and a suction port 3 and a discharge port 4 formed in the body a.

When this gear pump is driven, the working oil sucked from the suction port 3 is confined in the tooth space of the gear 5 and discharged from the discharge port 4.

Then, a high-pressure area and a low-pressure area are defined on the back surfaces of the bushes 1 and 2, that is, on the side surface opposite to the surface on which the gear 5 comes into contact, and the loading force is balanced by the pressure acting on these areas. I have to.

Then, when this gear pump is rotated, its tooth gap G
₁ rotates 1 pitch until just before reaching the groove G ₂ ,
The hydraulic oil is charged from the suction port 3, but the amount of the charge tends to be insufficient at the time of high speed rotation, which causes bubbles to be generated in the tooth groove G ₂ .

When the amount of hydraulic oil charged to the tooth space is insufficient, the above shortage is charged by the high-pressure oil leaking from a small gap such as the tooth tip or tooth flank of the gear 5.

On the other hand, when the gear 5 rotates at a low speed, the amount of hydraulic oil leaking to the tooth groove G ₂ on the high pressure side increases, and there is almost no shortage of charge, so the pressure in the tooth groove G ₂ tends to rise.

By (invention Problems to be Solved) charge shortage at the time of high-speed rotation as described above, when the bubble is generated in the tooth space G _2, when the tooth space G ₂ is a high-pressure oil introduced in communication with the speed slot 6 , Because the bubbles are rapidly collapsed, locally generate ultra high pressure. Therefore, the body a and the bushes 1, 2 around the tooth space are
There was a problem of causing erosion.

Furthermore, during low-speed rotation, an increasing number of leakage of high pressure oil to the tooth space G ₂ As described above, since within the tooth space G ₂ is high, the loading force tends to be insufficient. That is,
The high pressure area H on the back surface of the bush 1 is maintained in the range shown in the figure, and the position of the tooth space G ₂ is the low pressure area L. Therefore, when the pressure in the tooth groove G ₂ becomes high, the tooth groove pressure becomes larger than the force on the back surface of the bush, and the bush 1 separates from the side surface of the gear 5.

If the bush 1 is separated from the side surface of the gear 5, the gap between them becomes large, which is also a cause of remarkably deteriorating the volumetric efficiency.

This invention prevents the generation of erosion by preventing bubbles in the tooth groove at a predetermined position from rapidly abating at the time of high speed rotation, and prevents the pressure in the tooth groove from rising at the time of low speed rotation, thereby increasing the loading force. The purpose is to provide a gear pump that is balanced.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a body with a pair of gears, and a side surface of the gears is provided with a bush or a side plate, while an opening is provided on the suction port side. The tooth groove portion of the bush or the side plate that communicates with the tooth root portion of the tooth groove and the tooth root portion of the tooth groove that is adjacent to the tooth groove and is in the rotational position where communication with the suction port is blocked. It is formed on the gear contact surface.

(Operation of the Invention) With the above-described configuration, during high speed operation of the gear pump, the low pressure oil on the suction side flows into the tooth space at the adjacent rotation position. Further, during low speed operation, the high pressure in the adjacent tooth space is released to the suction port side.

(Effects of the Present Invention) According to the present invention, even if bubbles occur in the tooth space during high-speed operation of the gear pump, the bubbles are gently crushed by the low-pressure oil on the suction side, so that erosion can be prevented. Moreover, since the oil passage is opened at the tooth root portion, the low pressure oil positively flows into the oil passage due to the kinetic energy of the suction flow. Therefore, the occurrence of erosion can be prevented more reliably.

Further, since the oil passage communicates between the root portions of the tooth groove, the pressure oil in the tooth groove on the high pressure side does not escape to the low pressure side even during high-speed operation of the pump. For example, during high speed operation, the pressure oil in the tooth space tends to escape to the outside of the tooth space by the action of centrifugal force. Therefore, if the oil passage is opened to the tooth tip side, the pressure oil in the high pressure side tooth groove escapes into the low pressure side tooth groove during the high speed operation. For this reason, if the oil passage is open to the tooth tip side, the pump efficiency during high-speed operation will be significantly reduced. However, with this device,
As described above, since the oil passage communicates between the root portions of the tooth groove, the high pressure oil does not escape even during high speed operation. Therefore, the pump efficiency during high speed operation is not deteriorated.

Further, during low speed operation, the high pressure in the adjacent tooth space is released to the suction side, so that the balance of the loading force is not lost.

(Embodiment of the present invention) A body a of this gear pump is internally provided with a pair of gears 11 and 12, and bushes 13 and 12 are provided on both sides of the gears 11 and 12, respectively.
14 along with 15 and 16.

Since the bushes 13, 14 and 15, 16 are symmetrical, only one side, which is one of the bushes 13, 14 will be described below.

The bushes 13 and 14 are the contact surfaces 17 and 18 with the gears 11 and 12, and form a recess 20 at a position corresponding to the suction port 19, and the low-pressure oil introducing portion is adjacent to the recess 20. 21, 2
2 and oil passages 23, 24 are formed.

The low-pressure oil introduction portions 21, 22 and the oil passages 23, 24 have backflow prevention walls 25, 26 and 27, 28 at the boundary with the recess 20.

The oil passage grooves 23, 24 are longer than the tooth thickness of the thickest part of the gears 11, 12, and when the teeth are located at the center of the oil passage groove 23 as shown in FIG. Both ends of the tooth are opened to the root portions of the tooth grooves on both sides of the tooth.

Then, when the gears 11 and 12 are rotated in the direction of the arrow 29, the low pressure oil is sucked into the suction port 19. At this time, gears 11, 1
Since No. 2 rotates in the direction opposite to the suction flow, the suction flow and the gear collide with each other. Due to this collision, very large kinetic energy is generated in the suction flow.

As shown in FIG. 4, the suction flow having the large kinetic energy is pushed into the low pressure oil introduction recesses 21 and 22 along the tooth roots of the gears 11 and 12, and the flow reflected at the tooth roots is the reverse flow. It collides with the inside of the prevention walls 25 and 26 and is pushed into the low pressure oil introduction recesses 21 and 22 as well.

The suction flow thus pushed into the low pressure oil introduction recesses 21, 22 passes through the grooves 30, 31 formed in the bushes 13, 14 to lubricate the gear shaft, and then returns to the suction port 19 side again.

Also, when the gears 11 and 12 rotate, the oil flow groove is operated on the same principle as that the suction flow is pushed into the low pressure introduction recesses 21 and 22.
The suction flow is also pushed into 23 and 24.

Then, when the gear pump is operated at high speed, bubbles are generated in the tooth groove G ₂ as described above, but since the tooth grooves G ₁ and G ₂ communicate with each other through the oil passage grooves 23 and 24, The low-pressure oil thus pushed into the oil passages 23, 24 flows into the tooth groove G ₂ containing air bubbles. The low pressure oil that flows into the tooth space G ₂ gently crushes the bubbles, so that the erosion and the like as in the conventional case does not occur.

On the other hand, during low-speed operation of the gear pump is a high pressure oil from leaking tooth groove G _2, high-pressure oil that has leaked into the tooth spaces G ₂ is, since the return to the suction port 19 side via the Tsuyumizo 23, The pressure in the tooth groove G ₂ becomes too high and the balance of the loading force is not lost.

It should be noted that, when the oil passage grooves 23 and 24 are opened to the tooth spaces G ₁ and G ₂ as described above, it is more effective to open to the root side of these tooth spaces as shown in the figure. The reason for this is as follows.

That is, the hydraulic oil sucked into the tooth groove G ₁ tends to concentrate on the outer side of the tooth groove due to the centrifugal force acting in the process of reaching the tooth groove G ₂ , and the pressure on the tooth root side becomes relatively low accordingly. . Therefore, if the oil passages 23 and 24 are opened on the tooth bottom side where the pressure is low,
That is, the low pressure oil on the suction side is sufficiently supplied to the gear groove G ₂ .

If the oil passages 23, 24 are opened on the tooth tip side, the following inconvenience occurs.

When the oil passage groove is open to the tooth tip side, the pressure oil concentrated on the outside due to the action of centrifugal force is generated in the oil passage groove when the pump is in operation.
Escapes at low pressure via 23 and 24. As a result, the pump efficiency during high-speed operation is significantly reduced.

However, in this embodiment, as described above, the oil passages 23, 24 are
Since the tooth spaces of the tooth spaces G ₁ and G ₂ are communicated with each other, the high pressure oil does not escape even during high speed operation. Therefore, the pump efficiency during high speed operation is not deteriorated.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention,
1 is a sectional view, FIG. 2 is a perspective view of a bush, FIG. 3 is a schematic view showing the relationship between the side surface of the bush and a gear, and FIG. 4 is a state in which low-pressure oil is pushed into a low-pressure oil introduction recess. FIG. 5 is a sectional view of the main part shown, and FIG. 5 is a schematic view showing the relationship between the bush and the gear of the conventional gear pump. a ... Body, 11 ... gear, 13 to 16 ... bush, 19 ... suction port, 23,24 ... Tsuyumizo, G _1, G ₂ ... tooth space.

Claims (1)

[Scope of utility model registration request] [Claim 1] and interior a pair of gears 11, 12 to the body a, the side surface of the gear 11 and 12, while providing the bushing 13 to 16 or the side plates, the teeth of the tooth space G ₁ which opens to the suction port 19 side The oil passage groove 23 for communicating the root portion with the tooth root portion of the tooth groove G ₂ which is adjacent to the tooth groove G ₁ and is in the rotation position where the communication with the suction port 19 is blocked is provided in the bush or the side plate. A gear pump characterized by being formed on a gear contact surface.