JPH08303357A - Gear pump or motor - Google Patents

Abstract

PURPOSE: To improve volume and mechanical efficiencies by appropriately attaching a side board to a gear side face even in the case of reversing high and low pressure ranges. CONSTITUTION: A high pressure range is dividingly formed into a 3-letter shape or an inverse 3-letter shape according to rotating direction by a seal member 8 so that appropriate pressure balance to a side board 5 is provided. And the first sealing part 81 which is so arranged as to be in a high pressure range at all times even in the case of reversing high and low pressures is formed into a U-shape in cross section to introduce pressurized liquid in its inside so that internal stress generated in a thick-wall part of the sealing member 81 is prevented from transmitted in the vertical direction. A dogleg shaped part of a solid sealing member 82 which is positioned across a seal land point and in the low pressure side is thus free from any application of excessive compression force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump or motor of a type in which a high and low pressure region is reversed between a pair of inlets and outlets, such as a double rotary motor.

[0002]

2. Description of the Related Art In a gear motor, a pair of gears meshing with each other is arranged in a case, and a pressure liquid is supplied to one of a pair of inlets and outlets that are opened in a meshing portion of both gears to flow from the inlet and outlet. While the liquid is confined in the tooth space of the gear, the liquid is forcibly pressed against the gear while moving to the other inlet / outlet, and at that time, rotational power is applied to the gear. In addition, the gear pump drives the gears in a synchronous reverse rotation,
The liquid sucked from one inlet / outlet is guided to the other inlet / outlet and discharged. In such a gear pump or motor, in order to improve volumetric efficiency and mechanical efficiency, the side surface of the gear must be surely sealed by the side plate, and the side plate is excessively pressed against the side surface of the gear and slides. The pressing force must also be appropriate so that the resistance does not increase. Therefore, conventionally, a seal groove is provided on the surface of the side plate on the side opposite to the gear to bury the seal member, and the pressure liquid is introduced from the gear side to the area surrounded by the side plate, the seal member and the case, so that the side plate has an appropriate force. It is pushed back to the side surface of the gear, and is appropriately attached to the side surface of the gear for sliding sealing.

By the way, the high pressure region appearing on the gear side is
Gear mesh position and ± 18 in the circumferential direction from this mesh position
The pump / motor has a three-letter shape that connects a pair of seal land points that are rotated by 0 ° or more. Of these, the pump / motor that reverses the high / low pressure at the inlet / outlet, the high-pressure region is the three-letter shape or the reverse. It appears inverted in one of the three shapes. Therefore, as the seal member, a seal member having a figure 8 shape in which angular protrusions are formed at four locations corresponding to the seal lands for partitioning high pressure and low pressure is used, and the high pressure region has a figure 3 shape. In either case, the hydraulic pressure can be balanced regardless of the inverted three-letter shape.

It is generally known that the seal member is entirely solid or has a U-shaped cross section.

[0005]

However, in the case where the whole is solid, for example, a high pressure in the shape of 3 is generated on the gear side,
Along with this, when the pressure liquid is introduced to the surface of the side plate on the side opposite to the gear, stress is generated inside by the pressing of the seal member against the high pressure liquid, and this internal stress is transmitted in the longitudinal direction and is transmitted to the seal land. It acts as a force that compresses the seal member from the high pressure side to the low pressure side with the point as a boundary. For this reason,
When the high and low pressures are reversed and a repeated load is applied, the "V" shape area of the seal member existing on the low pressure side flaps due to repeated compression / expansion, causing early deterioration and the "V" shape. When the internal stress of the seal member acts as a compressive force on the region, the seal member relieves the stress and thus floats up from the groove in a direction perpendicular to the groove, which deteriorates the sealing property. Further, when the seal member floats up, the side plate is unduly biased, which causes a problem that the volume efficiency is lowered due to the occurrence of torque loss and the side plate being pushed one side.

On the other hand, when the entire seal member has a U-shaped cross section, the seal member balances the hydraulic pressure outside and inside the U-shape in the high pressure region, and it becomes difficult for internal stress to be transmitted in the longitudinal direction of the seal member. For this reason, the problems like the solid ones described above are eliminated, but on the other hand, since the high pressure also flows into the low pressure region through the inside of the U-shape, the pressure balance between the side plate and the gear side surface is lost, and the side plate Will be forced strongly against the side of the gear. For this reason, it also causes torque cross, and side leakage increases, which causes a problem that volumetric efficiency of the pump or motor is significantly reduced.

The present invention has been made in view of such a problem, and even if the high and low pressure regions are reversed by use, the side plate can be attached to the side surface of the gear under proper pressure balance. The purpose is to realize a gear pump or a motor as described above, and thereby effectively improve the volumetric efficiency and mechanical efficiency.

[0008]

In order to achieve the above object, the present invention employs the following configuration.

That is, in the gear pump or motor of the present invention, a pair of gears meshing with each other is arranged in the case, and a seal groove provided on the side opposite to the gear is provided between the gear side surface and the case. In the one in which a side plate formed by mounting a V-shaped seal member is interposed, and a pressure liquid is introduced from a high pressure region on the gear side to a region surrounded by the side plate, the seal member and the case, among the seal members, Even if the high and low pressures are reversed, the area that corresponds to the area where the pressure is always high has a U-shaped cross section into which the pressurized liquid is introduced, and the area that corresponds to other areas is solid. The feature is that

[0010]

With this structure, a high pressure region is generated on the gear side surface of the side plate due to the operation of the gear pump or the motor, and accordingly, the side plate, the seal member and the case are also formed on the opposite gear side surface. When the pressurized liquid is introduced into the area surrounded by, the cross-section U of the figure 8 seal member
The pressure liquid is introduced into the U-shaped part, high pressure is generated around the part corresponding to the high pressure side of the pair of solid parts on both sides of the U shape, and the part corresponding to the low pressure side becomes low pressure. Retained. Therefore, a pressure distribution similar to that obtained when the three-shaped seal member used for one-sided rotation is used is obtained. That is, for the high pressure region of the shape of 3 generated on the gear side,
The high pressure area appears in an inverted 3 shape by the seal member even on the opposite gear side, and the pressure liquid is not introduced into the 8 shape, so the side plate should be attached to the side of the gear under proper pressure balance. Can be kept. Moreover, in the U-shaped portion, the hydraulic pressure introduced into the inside and the hydraulic pressure applied from the outside balance in the direction orthogonal to the longitudinal direction of the seal member, so that the internal stress generated within the thickness of the seal member. Is transmitted in the longitudinal direction and does not exert an excessive compressive force on the "V" shaped portion of the seal member on the low pressure side beyond the seal land point. Therefore, it is possible to effectively prevent the seal member from fluttering due to the repeated load and from rising from the groove of the seal member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view of the gear pump.
2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is a sectional view taken along line III-III in FIG.

As shown in FIG. 1, this gear pump accommodates a pair of gears 3 and 4 in a meshed state between a front case 1 and a body-integrated rear case 2. The rear case 2 has a spectacle-shaped hole 21 at a portion adjacent to the joining end surface 2a.
The inner end face 21a of the hole 21
Bearing holes 22 and 23 are formed in the
Bushings 24 and 25 are fitted in the housing 3. The front case 1 is also provided with bearing holes 12 and 13 at portions corresponding to the bearing holes 22 and 23, and bushes 14 and 15 are similarly fitted into the bearing holes 12 and 13, respectively. The drive shaft 31 in which the drive gear 3 is attached to the bushes 14 and 24
And the bushes 15 and 25 support the driven shaft 41 on which the driven gear 4 is mounted. As shown in FIG. 2, the rear cover 2 has a pair of entrances and exits 6 and 7 at positions facing the meshing portion O of the gears 3 and 4, respectively.

Further, one side surface 3a of the gears 3, 4 is
4a and the rear case 2, and the other side surface 3b,
Side plates 5 are respectively disposed between the front case 1 and the front case 4b. The side plate 5 includes the side surfaces 3a of the gears 3 and 4,
3b, 4a, and 4b are provided to seal the volume space, and as shown in FIGS. 2 and 3, the overall contour is a shape in which gear pairs 3 and 4 meshing with each other are projected from the axial direction. Two shaft holes 51 and 52 are punched out.

Then, the liquid that has flowed in from the one inlet / outlet port 6 or 7 is caused to flow out to the other outlet / inlet port 7 or 6, so that it can function as a pump or a motor. In other words, when this pump / motor operates as a motor, the pressure liquid supplied to one of the inlets / outlets 6 and 7 is forcibly pressed against the gears 3 and 4 while the pressure liquid is confined in the tooth space, while the other inlet / outlet 7 6, the rotational power is applied to the gears 3 and 4 in the meantime. Further, when performing a pumping action, the gears 3 and 4 are driven in a synchronous reverse rotation by an external power source to guide the liquid sucked from one of the inlets and outlets 7 to the other and discharge it.

In such a gear pump or motor, in order to enhance the volumetric efficiency and the mechanical efficiency, the gears 3, 4 are
It is necessary to surely seal the side surfaces 3a, 3b, 4a, 4b of the gears by the side plate 5, and moreover, the side plate 5 may be excessively pressed against the gear side surfaces 3a, 3b, 4a, 4b to increase the sliding resistance. The pressing force must be appropriate so that it will not occur. That is, when the gear pump or the motor is operated, for example, as shown in FIG. 8, the meshing position O of the gears 3 and 4 and ± 180 in the circumferential direction from this meshing position O.
The area between the pair of seal land points P and Q located at a position rotated by more than 0 ° has a high pressure as shown by the hatching in the figure. When this rotates in the reverse direction, the high-pressure region is inverted so as to be line-symmetric with respect to the straight line connecting the axes of the drive shaft 31 and the driven shaft 41. The seal land points at this time are R and S. In any case, the side plate 5 in the high pressure region has the gear side surfaces 3a, 4a, 3b, 4b.
To get away from it, you need a pressure balance to push it back.

Therefore, a seal groove 53 as shown in an enlarged view in FIG. 4 is provided on the surface of the side plate 5 on the side opposite to the gear, and the seal groove 53 has a figure 8 shape as shown in FIG.
I am wearing. Further, a notch 54 is provided at an end portion in the longitudinal direction of the side plate 5, and the pressure liquid is introduced into the surface of the side plate 5 on the side opposite to the gear via the notch 54. More specifically, the seal groove 53 is a region where the high pressure and the low pressure are always high, that is, a pair of seal land points P-R.
And a wide first groove portion 53a formed in a substantially semicircular region between Q and S and other regions, that is, between seal land points PQ and between R and S. A second groove portion 53b formed in the "-shaped region" and having a groove width of at least 1/2 or less of the groove portion, and the drive shaft 3 or the driven shaft 4
With reference to each of the seal land points P, Q, R,
And a third groove portion 53c extending radially from S to the position of the rear case hole 21. A pressure introducing groove portion 53a1 wider than the notch 54 and extending in the radial direction is provided in the center portion of the _first groove portion 53a. On the other hand, the seal member 8 has a first seal portion 81 which has an 8-shape and is fitted into the first groove portion 53a,
Second seal portion 82 fitted in the second groove portion 53b
And the third seal portion 83 fitted into the third groove portion 53c are integrally molded by an elastic body such as resin. That is, the first seal portion 81 and the second seal portion 82
Continuously form an 8-shaped endless seal member, and the third seal portion 83 constitutes an endless seal member. Further, of the seal member 8, the first seal portion 81 fitted into the first groove portion 53a has a U-shaped cross section as shown in FIGS. Groove 5
The second seal portion 82 fitted in 3b is shown in FIGS.
It is assumed to be solid as shown in. The first seal portion 81 is attached to the seal groove 53 in a state where the inside thereof is opened toward the first groove portion 53a.

With such a structure, a high pressure region as shown by hatching in FIG. 8, for example, is generated on the gear side surface of the side plate 5 due to the operation of the gear pump or the motor, and the reaction occurs accordingly. When the pressure liquid is introduced into the area surrounded by the side plate 5, the seal member 8 and the rear case 2 on the gear side surface as well, the high pressure area becomes as shown by the hatching in FIG. That is, of the sealing member 8 of the figure-eight, through the notch 54 and pressure introduction groove 53a ₁ of the side plate is introduced liquid in the first seal portion 81 which forms a cross-sectional U-shape, the U-shaped A high pressure is generated around the portion corresponding to the high pressure side of the pair of "V" -shaped second seal portions 82 on both sides of the shape, and a portion corresponding to the low pressure side is kept at the low pressure. At this time, the third seal portion 83 is liquid-tightly contacted with the third groove portion 53c of the side plate 5 by the hydraulic pressure F introduced into the U-shape. Therefore, the same high-pressure distribution as that obtained when the three-shaped seal member used for one-sided rotation is used can be obtained.
In this way, by making a part solid, it is not necessary to introduce the pressure liquid to at least the low pressure corresponding portion,
The side plate 5 can be attached to the side surface of the gear under proper pressure balance. Moreover, in the U-shaped first seal portion 81, the hydraulic pressure F ₁ introduced inside and the hydraulic pressure F ₂ acting from the outside are in the longitudinal direction of the seal member 8 as shown by the arrow in FIG. The internal stress generated in the wall thickness of the seal member 8 is balanced in the orthogonal direction and is transmitted in the longitudinal direction to exceed the seal land points P and Q, and to the second V-shaped seal portion 82 on the low pressure side. Does not exert excessive compression force. Therefore, the second seal portion 82 repeatedly flaps under a load, and the second groove portion 53b
It is possible to effectively prevent the situation of floating from the above, thereby ensuring a proper sealing function and a uniform pressure balance state with respect to the side plate 5. In particular, in this embodiment, since the second seal portion 82 is made as thin as possible, even if a compressive force acts from the high pressure side to some extent, it is possible to keep the amount of elastic deformation negligible. it can.
The above functions are the same even when the high and low pressure regions are reversed.

The specific construction of each part is not limited to the above-described embodiment, but various modifications can be made without departing from the spirit of the present invention.

[0020]

As described above, the gear pump or the motor of the present invention is provided with an 8-shaped seal groove on the surface on the side opposite to the gear side of the side plate, and among the seal members installed in this seal groove, Even if the high and low pressures are reversed, the part that substantially corresponds to the region that is always high has a U-shaped cross section through which the pressurized liquid is introduced, and the parts that substantially correspond to the other regions are solid. It is a thing. Therefore, regardless of the orientation of the high pressure region, a high pressure region for proper pressure balance can always be generated at a position corresponding to the high pressure region on the gear side, and at the same time, the U-shaped seal member in the high pressure region is hydraulically operated from inside and outside. By balancing, it is possible to reliably prevent the extension of the seal member in the low-pressure region, and eventually the fatigue due to the repeated load and the rise from the seal groove.

As described above, the gear pump or motor of the present invention is used as a double-rotation type or has a high entrance / exit.
Even if the reverse connection is performed at a low pressure, the seal member can be appropriately slidably contacted with the side surface of the gear to maintain the volume efficiency and the mechanical efficiency at high values.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a view showing a surface of the side plate on the side opposite to the gear according to the embodiment.

FIG. 5 is a view showing a seal member attached to the same side plate.

6 is a sectional view taken along line VI-VI in FIG.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is an operation explanatory view corresponding to FIG.

FIG. 9 is an operation explanatory view corresponding to FIG.

[Explanation of symbols]

 1 ... Front case 2 ... Rear case 3, 4 ... Gear 5 ... Side plate 8 ... Seal member

Claims (1)

[Claims] 1. A pair of gears that mesh with each other are provided in a case, and between the side faces of the gears and the case,
In order to introduce a pressure liquid from a high pressure area on the gear side into a region surrounded by the side plate, the seal member and the case, by interposing a side plate formed by mounting an 8-shaped seal member in a seal groove provided on the side opposite to the gear. In the gear pump or motor described above, a portion of the seal member, which substantially corresponds to a region where the high pressure and the low pressure are always high, is made to have a U-shaped cross section into which the pressurized liquid is introduced. A gear pump or motor characterized in that a portion substantially corresponding to the other region is solid.