JPH11236883A - Side plate for gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear track depth optimum to a gear pump in a short time and at a low cost. SOLUTION: This gear pump comprises an outer periphery having a curvature coinciding with that of the inner periphery of the gear hole of a body; and the shaft through-holes 22 and 23 of a gear. Shaft through-holes 22 and 23 are fitted in a winding bush protruded from a cover, and positional alignment with the body and the cover is carried out. In a so formed side plate 21 for a gear pump, the centers 22a and 23a of the shaft through-hole are positioned in deviation from the curvature centers 21c and 21d of the outer periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side plate used for a gear pump that performs relative positioning between a body and a cover using a winding bush.

[0002]

2. Description of the Related Art FIG. 3 shows a general gear pump, for example. In this gear pump, as shown in FIG. 3, a gear hole 2 is formed in a body 1, and a drive gear 3 and a driven gear 4 mesh with each other in the gear hole 2. A first cover 5 is attached to one end of the body 1. The first cover 5 has a drive shaft hole 6 and a driven shaft hole 7 formed therein.
The winding bushings 8 and 9 are incorporated in the motor. The ends of these winding bushes 8 and 9 project from the mounting surface of the first cover 5, respectively.

When the first cover 5 is attached to the body 1, a side plate 10 is fitted into the opening end of the gear hole 2. As shown in FIG. 4, curvature portions 10 a and 10 b are formed on the outer periphery of the side plate 10, and have a shape corresponding to the inner periphery of the opening of the gear hole 2 into which the side plate 10 is fitted. Therefore, the position of the side plate 10 with respect to the body 1 is determined by the outer periphery of the side plate 10. The side plate 10 has shaft through holes 11 and 12 formed therein.
A winding bush 8 having an inner diameter of 1, 12 provided on the first cover 5;
9 and the outer diameter of the protrusion. The projecting portions of the winding bushes 8 and 9 are fitted into the shaft through holes 11 and 12, respectively.

When the first cover 5 is mounted, the shaft 3a of the drive gear 3 and the shaft 4a of the driven gear 4 pass through the shaft through holes 11 and 12. The inner peripheral surfaces of the winding bushes 8 and 9 having the projections fitted in the shaft through holes 11 and 12 are provided with the drive gear 3.
And the shaft 4a of the driven gear 4 are rotatably supported. As described above, the projections of the winding bushes 8 and 9 are fitted into the shaft through holes 11 and 12 so that the side plate 10 of the first cover 5 is formed.
, And thus the body 1. The curvature portion 10a
Of the drive shaft through hole 11 and the center of curvature 10d of the curvature portion 10b and the center 12a of the drive shaft through hole 12.
And are respectively matched.

On the other hand, the other end of the body 1 has a second cover 1
3 is installed. A drive shaft hole 14 and a driven shaft hole 15 are also formed in the second cover 13.
Winding bushes 16 and 17 are incorporated in these shaft holes 14 and 15. And these winding bushes 16, 17
, The shaft 3b of the drive gear 3 and the shaft 4b of the driven gear 4 are rotatably supported. The ends of the winding bushes 16 and 17 assembled on the side of the second cover 13 are also connected to the second cover 1.
3 protrudes from the mounting surface.

When the second cover 13 is attached to the body 1, a side plate 18 is fitted into the opening end of the gear hole 2. As shown in FIG. 4, the side plate 18 has curvature portions 18a and 18b formed on the outer periphery thereof in the same manner as the side plate 10 and has a shape corresponding to the inner periphery of the opening of the gear hole 2. ing. Therefore, the position of the side plate 18 with respect to the body 1 is determined by the outer periphery of the side plate 18. In the side plate 18, a drive shaft through hole 19 and a driven shaft through hole 20 are formed. When the second cover 13 is attached, these shaft through holes 1
The projecting portions of the winding bushes 16 and 17 are fitted into 9 and 20 so as to position the second cover 13 relative to the body 1.

The shaft 3b of the drive gear 3 is
It protrudes outside from the second cover 13 and is connected to a drive source (not shown). In the gear pump described above, in a state where the side plates 10 and 18 are incorporated in the gear holes 2 formed in the body 1, the winding bushes 8 and the shaft through holes 11, 12, 19 and 20 formed in the side plates 10 and 18 are formed. The first and second covers 5 and 13 are positioned by fitting the projections 9, 16 and 17. Therefore, the first and second covers 5, 13 and the winding bushes 8, 9, 16, 17 can be positioned with respect to the body 1 without using a separate member such as a positioning pin.

Although not specifically shown, the back surfaces of the side plates 10 and 18 are divided into a high-pressure area and a low-pressure area. Then, the pressure on the discharge side and the pressure on the suction side are led to each area. The side plates 10 and 18 thus moved to the gears 3 and 4 according to the pressure distribution, and adjust the gap between the gears 3 and 4 to eliminate leakage therefrom. .

The gear pump as described above performs a break-in operation after being once assembled, and forms a gear track in the gear hole 2 of the body 1. Gear hole 2 during operation of gear pump
Inside, the discharge side is a high pressure area and the suction side is a low pressure area, so that the drive gear 3 and the driven gear 4 are pressed against the low pressure side. Thus, on the low pressure side in the gear hole 2, a gear track is formed by the gears 3 and 4. When the gear track is formed in this way, during operation of the gear pump, several teeth of each of the gears 3 and 4 located on the low pressure side in the gear hole 2 are pressed against the body 1, and both the high pressure side and the low pressure side are interposed. Thus, reliable sealing can be performed.
On the other hand, a gap is formed between the tooth tip and the gear hole 2 on the high pressure side,
By guiding the pressure on the discharge side between the plurality of teeth through the gap, pulsation of the discharge flow can be reduced.

As described above, the gear pump performs a break-in operation after assembling the parts to form a gear track on the low pressure side in the gear hole 2. The depth of this gear truck is
For example, it is as small as several tens μm to several hundred μm, and is determined by the position of the axis of each gear 3, 4, the size of the initial tooth gap, the pressure balance, and the like. for that reason,
This is because it is not possible to control the dimensions of each part from the beginning so that a gear track of the desired depth is always formed. Therefore, a running-in operation is performed to form a gear track once, and then adjust the depth as necessary. If the formed gear track is too deep or too shallow, the sealing performance on the low-pressure side is deteriorated, and the discharge efficiency is deteriorated.

[0011]

In order to adjust the gear track depth with the gear pump as described above, first and second gear pumps are required.
Shaft holes 6, 7, 14, 1 formed in the covers 5, 13
5 and the position and size of the gear hole 2 in the body 1 were changed. That is, the first and second covers 5, 13,
The design of the body 1 needed to be changed, which took time and cost. An object of the present invention is to obtain an optimum gear track depth in a short time and at low cost.

[0012]

According to a first aspect of the present invention, there is provided a gear pump side plate having an outer periphery having a curvature corresponding to an inner periphery of a gear hole in a body, and a gear shaft through hole, and protruding from a cover. In the gear pump side plate configured to fit the shaft through-hole into the winding bush and align with the body and the cover,
The center of the shaft through hole is shifted from the center of curvature of the outer periphery. The second invention is characterized in that the center of the shaft through hole is shifted from the center of curvature of the outer periphery to the low pressure side during the operation of the gear pump. A third invention is characterized in that the center of the shaft through hole is shifted from the center of curvature of the outer periphery to the high pressure side during the operation of the gear pump.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Side plates 21 and 24 shown in FIGS. 1 and 2 are used by being incorporated in the gear pump shown in FIG. The side plate is also incorporated at the opening end of the gear hole 2 on the second cover 13 side.
Since the same components as those on the first side are attached, the side plates 21 and 24 to be incorporated into the opening ends on the first cover 5 side are used here.
It will be described as. And these side plates 2
1 and 24 are incorporated in a gear pump such that the A side is a low pressure side and the B side is a high pressure side in FIGS.

The projections of the bushes 8, 9 provided on the first cover 5 are fitted into the side plate 21 of FIG. 1 similarly to the side plate 10 of FIG. 4, and the shafts 3a, 4a of the gears 3, 4 are attached. Drive shaft through hole 22 to be penetrated
And a driven shaft through-hole 23 are formed. Further, the curvature portions 21a and 21b on the outer periphery of the side plate 21 are provided.
Has a shape that matches the inner circumference of the opening of the gear hole 2 into which the side plate 21 is fitted. However, the center of curvature 21c of the curvature portion 21a and the center 22a of the drive shaft through hole 22 are defined by the center of curvature 21d of the curvature portion 21b and the center 23a of the driven shaft through hole 23.
Are not matched, and are shifted by the shift amount δ. Here, the center 22a, 23a of the shaft through hole 22 is
It is shifted toward the lower pressure side A from the center of curvature 21c, 21d on the outer periphery.

The side plate 24 shown in FIG. 2 also has a drive shaft through-hole 25 and a driven shaft through-hole 26 into which the bushes 8 and 9 are fitted, and the outer peripheral curvature portions 24a and 24b are connected to the other side plates. Like the plate, the gear hole 2 has a shape that matches the inner circumference of the opening. In the side plate 24, opposite to the side plate 21, the centers 25a and 26a of the shaft through holes 25 and 26 are shifted from the centers of curvature 24c and 24d by δ toward B on the high pressure side. I have.

Next, such side plates 21 and 2
The method of adjusting the gear track depth using FIG. 4 will be described. First, a gear pump is assembled by incorporating the conventional side plate 10 shown in FIG. Then, a running-in operation of the assembled gear pump is performed to form a gear track. If the gear track formed at this time is too shallow, the gear pump is assembled by incorporating the side plate 21 instead of the side plate 10, and the running-in operation is performed again.

The centers 22a and 23a of the shaft through-holes 22 and 23 of the side plate 21 correspond to the center of curvature 2 of the outer periphery.
It is shifted by δ in the direction A on the low pressure side from 1c and 21d. In other words, the side plate 10 that was initially incorporated
The center of the shaft through-holes 22 and 23 of the side plate 21 is shifted to the low pressure side from the center of the shaft through-holes 11 and 12. Therefore, in the gear pump in which the side plate 21 is assembled, the gears 3 and 4 incorporated in the gear hole 2 are pushed to the low pressure side from when the side plate 10 is assembled. If the break-in operation is performed in this state, a deeper gear track can be formed.

Conversely, if the formed gear track is too deep in the running-in operation incorporating the side plate 10, the center of the shaft through hole of the side plate is shifted by δ to the high pressure side from the center of curvature of the outer periphery. A side plate 24 is used. In this case, since the body 1 having the gear track which is too deep cannot be used, the gear pump is assembled by incorporating the side plate 24 into another body 1 which has not formed the gear track yet. In this gear pump, the shaft through hole 2 formed in the side plate 24
The centers 25a, 26a of 5, 26 are shifted to the high pressure side. Therefore, even if pressure is applied during the running-in operation, the pressing force on the low pressure side is weaker than when the side plate 10 is incorporated, and a shallow gear track can be obtained.
In this way, by simply replacing the side plate, the depth of the gear track can be adjusted and an optimal gear track can be formed.

As described above, if the center of the shaft through hole formed in the side plate is shifted to the low pressure side or the high pressure side from the center of curvature of the outer periphery, the first and second shift amounts are shifted by the shift amount δ.
The positions of the second covers 5 and 13 are also shifted. However, this deviation δ is set within the range of the play between the other parts, and the deviation of the positions of the first and second covers 5 and 13 due to the deviation δ is absorbed by the play between the parts. I have to. The play is a play in a bolt hole for fixing the first and second covers 5, 13 to the body 1, a gap between a bush and a shaft, and the play of the bolt is usually about 1 mm. The gap between the shaft and the shaft is 100μm
~ 150μm, gear tip clearance is 100μm ~ 150μ
m. On the other hand, the shift amount δ is usually set to 100 μm or less.

For this reason, when a side plate having a different center of the shaft through hole is selected, the position of the bolt hole for mounting the first and second covers and the gap between the bush and the shaft need not be changed. The gear pump can be assembled by incorporating it. That is, there is no need to rework parts other than the side plate. The formation of the side plate is simpler than forming a gear hole in the body or forming a shaft hole in the cover. Therefore, it is not so difficult to prepare a side plate in which the center position of the shaft through hole is shifted in advance. Therefore, by preparing several types of side plates in which the center positions of the shaft holes are shifted and selecting an appropriate one from the prepared side plates, an optimal gear track can be formed in a short time and at low cost.

[0021]

By using the gear pump side plate of the present invention, the gear track depth of the gear pump can be easily adjusted. If several kinds of side plates with the center of the shaft through hole shifted from the center of curvature of the outer periphery are prepared in advance, an optimum gear track can be obtained by selecting and incorporating an appropriate side plate from among them. Can be. Therefore, the time and cost are reduced as compared with the conventional case where the cover and the body are re-formed in order to obtain the optimum gear track depth. By using the side plate of the second invention, a deeper gear track can be formed than in the case of using the conventional side plate. By using the side plate according to the third aspect of the invention, a shallower gear track can be formed as compared with the case where the conventional side plate is used.

[Brief description of the drawings]

FIG. 1 is a plan view of a side plate in which the center of a shaft through hole is shifted to a low pressure side in the side plate of the present invention.

FIG. 2 is a plan view of the side plate of the present invention in which the center of a shaft through hole is shifted to a high pressure side.

FIG. 3 is a sectional view of a gear pump.

FIG. 4 is a plan view of a conventional side plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Gear hole 3 Drive gear 4 Driven gear 3a, 3b Shaft 4a, 4b shaft 5 First cover 13 Second cover 6, 14 Drive shaft hole 7, 15 Driven shaft hole 8, 9-turn bush 16, 17-turn bush 21, 24 Side plate 22, 25 Drive shaft through hole 23, 26 Driven shaft through hole 21a, 21b Curvature portion 21c, 21d Center of curvature 24a, 24b Curvature portion 24c, 24d Center of curvature 22a, 23a Center of shaft through hole 25a, 26a Shaft through hole center

Claims (3)

[Claims] 1. An outer periphery having a curvature corresponding to an inner periphery of a gear hole of a body, and a shaft through hole of a gear. The shaft through hole is fitted into a winding bush protruding from a cover, and the shaft through hole is formed on the body and the cover. A side plate for a gear pump, wherein the center of the shaft through-hole is shifted from the center of curvature of the outer periphery in the side plate for a gear pump configured to be positioned. 2. The gear pump side plate according to claim 1, wherein the center of the shaft through hole is shifted from the center of curvature of the outer periphery toward a low pressure side during operation of the gear pump. 3. The side plate for a gear pump according to claim 1, wherein the center of the shaft through hole is shifted from the center of curvature of the outer periphery toward a high pressure side during operation of the gear pump.