JPH0625584U - Gear pump or motor - Google Patents

Abstract

(57) [Abstract] [Purpose] Internal leakage can be effectively reduced by adding simple components. [Structure] A tongue piece 8 extending axially between both end portions 6a of the three-shaped gasket 6 and corresponding portions 7a of the annular gasket 7.
a and a tongue piece 8b extending in a direction perpendicular to the axis, and integrated with the tongue piece mounting recessed portions 9a and 9b corresponding to the shapes of the tongue pieces 8a and 8b.
a and the cover joint surface 41.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gear pump or a motor (hereinafter referred to as a gear pump) used in various hydraulic equipment fields and the like.

[0002]

[Prior art]

 FIG. 2 shows an entire longitudinal section of a conventional gear pump, and FIGS. 3 and 4 show a front view and a perspective view of a rear cover which is a component thereof. The front cover is also omitted in the drawing because it has a similar structure to the rear cover. This gear pump has a body 3 having an eyeglass-shaped hole 31 for accommodating a pair of gears 1 and 2, and a joint surface 41 to be joined to an opening end surface 32 on the right side of the body 3. In the center of the joint surface 41, there are provided a rear cover 4 in which a cage portion 42 fitted in the hole 31 of the body 3 is provided to project, and a joint surface 51 to be joined to the left open end surface 33 of the body 3. The front cover 5 is provided with a seal part 52 fitted in the hole 31 of the body 3 at the center of the contact surface 51, and the end faces 43 of the seal parts 42, 52 of the covers 4, 5. 53, bearing portions 44, 45, 54, 55 which support the support shafts 11, 12, 21, 22 of the both gears 1, 2 by being fitted therein, and the seal portions of the covers 4, 5. The end faces 43, 53 are provided with recesses along the outer circumference of the bearings 44, 45, 54, 55. The pressure balance grooves 46 and 56, in which the three-shaped gasket 6 for high and low pressure regions is mounted, and the joint surfaces 41 and 51 of the covers 4 and 5 are recessed at positions surrounding the seal portions 43 and 53. And an annular groove 47, 57 into which an annular gasket 7 for preventing external leakage is installed. The three-piece gasket 6 and the annular gasket 7 are separate objects made corresponding to the shapes of the grooves 46, 56, 47, 57. Further, eyeglass-shaped side plates 61 that are movable in the axial direction for sealing the tooth side surfaces are additionally provided on both side surfaces of the gears 1 and 2, and the pressure baluns located on the back surface of these side plates 61 are attached. The side plate 61 is pressed toward the side surfaces of the gears 1 and 2 with an appropriate liquid pressure by guiding the pressure liquid to the groove 46 and 56, and in that state, the gears 1 and 2, the body hole 31 and the side plate 6 are formed. The well-known pumping action of confining the fluid in the volume space surrounded by and continuously transferring the fluid from the suction port IN side to the discharge port OUT side is performed. That is, as the gears 1 and 2 are operated, the portion where both ends 6a and 6a of the three-shaped gasket 6 are arranged becomes the suction side seal position S, and high pressure is applied to the leading side of the position S, It can be said that a low-efficiency pump has less internal leakage as low pressure appears on the delay side and the sealing effect at the position S is higher.

[0003]

[Problems to be solved by the device]

 However, the above-described structure has a problem to be solved that internal leakage that occurs between the body 3 and the covers 4 and 5 cannot be completely prevented. Hereinafter, the situation will be described by exemplifying a leak between the body 3 and the rear cover 4. In the conventional pump, as shown in FIG. 5, a body hole 31 is provided so that the body 3 and the cover 4 can be assembled. The inner diameter Db of the seal portion 42 is set to be larger than the outer diameter Dm of the seal portion 42. Therefore, even if the seal portion 42 comes into contact with the body hole 31 at the lowest point A, the seal portion 42 shifts in the left-right direction from the point A. A large gap E is formed between the outer circumference 42a of 42 and the body hole 31. Further, in order to make the assembly easier, as shown in FIG. 6, the outer circumference 42a of the cage portion is tapered in diameter from the end face 43 side toward the joint surface 41 side. Thus, a gap F having a triangular cross section is formed between the outer circumference 42a of the cage portion and the body hole 31. Then, the fluid gathers near the suction side seal position S through the gaps E and F. However, the end portion 6a of the three-shaped gasket 6 arranged at this portion has a thickness dimension smaller than the protruding height of the stamp portion 42, and does not cover the entire circumference 42a of the stamp portion. That is, a metal seal is provided between the outer circumference 42a of the cage portion and the body hole 31 corresponding to the portion where the gasket 6 does not exist. Similarly, the metal seal effect is expected by increasing the degree of adhesion between the cover joint surface 41 (the portion marked in the figure) and the body opening end surface 32. However, this type of metal seal generally has a lower sealing effect than a gasket, and the mounting posture of the body 3 and the cover 4 is slightly twisted, or the surface finish of the body opening end face 32 and the cover joint surface 41 is not perfect. In the case of being rough, the sealing effect is further reduced. Therefore, the fluid can pass through the suction side seal position S relatively easily. That is, as shown by the arrow X in FIG. 4, the fluid flowing into the suction port IN along the outer circumference 42a of the seal portion, or the fluid flowing into the suction port IN along the cover joint surface 41 as shown by the arrow Y, or As shown by an arrow Z, a fluid is generated which once flows from the cover joint surface 41 into the annular groove 47, rides on the cover joint surface 41 again, and flows into the suction port IN. For this reason, the conventional gear pump has a problem that internal leakage is large, which is a factor that hinders improvement in volumetric efficiency.

The present invention has been made in view of such a problem, and it is an object of the present invention to provide a gear pump or a motor that can effectively reduce internal leakage only by adding simple constituent elements. Has an aim.

[0005]

[Means for Solving the Problems]

 The present invention adopts the following configuration in order to achieve such an object.

That is, the gear pump or motor according to the present invention has a general configuration as a pump / motor of this kind, and both end portions of the three-shaped gasket arranged at the suction side seal position are provided. And the corresponding part of the annular gasket are integrated through the tongue extending in the axial direction and the tongue extending in the direction perpendicular to the axis, and the tongue mounting recess corresponding to the shape of these tongues is integrated. Is provided on the outer peripheral surface of the inro cage and the joint surface of the cover.

[0007]

[Action]

 With such a seal structure, when such an integrated gasket is attached to the cover, the three-shaped gasket is installed in the pressure balance groove, the annular gasket is installed in the annular groove, and the tongue extending in the axial direction is attached. The tongue piece is attached to the recessed portion provided on the outer periphery of the cover, and the tongue extending in the direction perpendicular to the axis is attached to the recessed portion provided on the joint surface of the cover. Then, when the body opening end face and the cover joint face are tightly joined in this state, those tongues cross the suction side seal position in the radial direction and connect the three-shaped gasket and the annular gasket. Therefore, the problem that the outer circumference of the cage and the inner circumference of the body hole, and the end surface of the body and the joint surface of the cover are in metal contact with each other in the past can be solved. That is, according to the present invention, even if the high pressure fluid gathers in the vicinity of the suction side seal position by interposing the tongue piece which is a gasket across the suction side seal position, the suction side seal position is Leakage to the low pressure side beyond is effectively prevented. Therefore, according to the present invention, the sealing effect at the suction side sealing position can be reliably improved as compared with the conventional one, and the effect of greatly reducing internal leakage can be obtained.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. The same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

This gear pump extends axially extending tongue 8a and a direction perpendicular to the axis between both ends 6a of the above-mentioned three-shaped gasket 6 and the corresponding portion 7a of the annular gasket 7. The gasket 10 is integrated with the tongue piece 8b and is formed as a whole. The thickness of the tongues 8a and 8b is equal to that of the gaskets 6 and 7. On the other hand, the outer peripheral surface 42a of the seal portion 42 is provided with a recessed portion 9a for mounting the tongue piece corresponding to the shape of the tongue piece 8a. A tongue mounting recess 9b corresponding to the shape of the tongue 8b is provided.

With such a seal structure, when the integral gasket 10 is mounted on the case 4, the three-shaped gasket 6 is mounted on the pressure balance groove 46, and the annular gasket 7 is mounted on the annular groove 47. The tongue 8a extending in the axial direction is attached to the recess 9a, and the tongue 8b extending in the direction perpendicular to the axis is attached to the recess 9b. Then, when the body opening end surface 32 and the cover joint surface 41 are tightly joined in this state, the tongues 8a and 8b of the tongue pieces 8a and 8b traverse the suction side seal position S in the radial direction and the three-shaped gasket 6 and the annular gasket 7 are crossed. I will contact you. Therefore, it is possible to solve the problem that the outer circumference 42a of the cage portion and the inner circumference 31 of the body hole, and the body opening end surface 32 and the cover joint surface 41 are in metal contact with each other. That is, according to the present invention, since the tongues 8a and 8b, which are gaskets, are provided across the suction side seal position S, even if the high pressure fluid gathers in the vicinity of the suction side seal position S, the suction side Leakage to the low pressure port IN side beyond the seal position S is effectively prevented. Therefore, according to the present invention, the sealing effect at the suction side sealing position S can be surely improved as compared with the conventional one, and the effect of greatly reducing internal leakage can be obtained. When the volumetric efficiency is improved in this way, the effect of significantly improving the pump performance can be obtained when the viscosity of the fluid is reduced, especially when used at high temperatures. Further, even if the mounting state of the body 3 and the rear cover 4 is slightly twisted or the surface finish of the body opening end face 32 and the cover joint surface 41 is somewhat rough, the presence of the tongues 8a and 8b ensures a uniform seal. Since the effect is maintained, there is also a practical effect that the required volumetric efficiency can be secured even if the processing and assembly precision is slightly reduced.

It is needless to say that such a structure can be applied between the body 3 and the front cover 5, and the specific cross-sectional shapes of the respective components do not depart from the gist of the present invention. Various modifications are possible within the range.

[0012]

[Effect of device]

 A gear pump or motor according to the present invention connects a three-piece gasket and an annular gasket via a tongue extending in the axial direction and a tongue extending in the direction perpendicular to the axis, and the tongues are connected to the case side. Since the recessed portion capable of accommodating the case is provided, when the body opening end surface and the case joint surface are brought into contact with each other, those tongues traverse between the three-shaped gasket and the annular gasket at the suction side seal position. The existing metal seal, that is, the outer circumference of the cage and the inner circumference of the body hole, and the end surface of the body opening and the joint surface of the case are reliably sealed, and internal leakage is effectively prevented. Will be done. As a result, when this seal structure is applied to a gear pump or a motor, the volumetric efficiency is surely improved as compared with the conventional one, and particularly the effect of improving the performance at high temperature use is obtained. In addition, there is a practical effect that the number of man-hours for assembling and assembling the body and cover can be simplified without reducing the volumetric efficiency.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a rear cover and a gasket according to an embodiment of the present invention.

FIG. 2 is an overall vertical sectional view showing a conventional gear pump.

FIG. 3 is a front view showing a rear cover of the pump.

FIG. 4 is an exploded perspective view showing a rear cover and a gasket according to a conventional example.

FIG. 5 is a diagram for explaining a conventional cause of leakage.

FIG. 6 is a diagram for explaining a conventional cause of leakage.

[Explanation of symbols]

 1, 2 ... Gears 3 ... Body 4 ... Rear cover 5 ... Front cover 6 ... Three-shaped gasket 6a ... Both ends 7 ... Annular gasket 7a ... Corresponding parts 8a, 8b ... Tongues 9a, 9b ... Recessed portions 11, 12 , 21, 22 ... Support shaft 31 ... Body hole 32, 33 ... Opening end surface 41, 51 ... Joining surface 42, 52 ... Inro section 43, 53 ... Inro end section 44, 45, 54, 55 ... Bearing section 46, 56 ... Pressure balance groove 47, 57 ... Annular groove

Claims (1)

[Scope of utility model registration request] 1. A body having a hole capable of accommodating a pair of gears in mesh with each other, and a joint surface to be joined to left and right open end surfaces of the body, respectively, and a hole of the body at the center of the joint surface. A pair of covers in which the cage portion fitted in the projecting portion is provided, bearing portions which are opened in the cage cage end surfaces of the covers and which support the shafts of the both gears by being fitted therein, and the bearings of the covers. A pressure balance groove is provided along the outer periphery of the bearing portion on the end face of the seal portion, in which a three-shaped gasket for high and low pressure compartments is mounted, and a concave portion is provided at a position surrounding the seal portion on the joint surface of the cover, and external leakage occurs. A gear pump or motor comprising: an annular groove into which a preventive annular gasket is mounted, wherein both ends of the three-shaped gasket and corresponding portions of the annular gasket are provided on a tongue piece and an axis extending in the axial direction. In the vertical direction A gear which is integrated through extending tongues and is provided with a concave notch for mounting the tongues corresponding to the shape of the tongues on the outer peripheral surface of the seal cage and the joint surface of the cover. Pump or motor.