JPH0821372A - Gear pump - Google Patents

Abstract

PURPOSE:To suppress the generation of defective products and the noise by providing a casing structure where the precision is easily obtained in compressing a sealing material in the direction different from the abutting direction of the mating reference surface of two cases. CONSTITUTION:A pump chamber is formed by a first case 3a and a second case 3b, and the substance to be carried is fed by a driving gear 1 and a driven gear which are engaged with each other in this pump chamber. In addition, a third case 3c to form a reduction gear chamber of the driving gear 1 in cooperation with the second case 3b and a fourth case 3d having a fixing part 3s to integrate the respective cases 3a, 3b, 3c with a fitting part 3g when the pump is fitted to an outside device are provided. An elastic sealing material 9 is interposed between the cases 3a, 3b, and the elastic sealing material 9 is compressed and held in the direction different from the direction where the reference surfaces 3x, 3y for alignment of the cases 3a, 3b are abutted on each other, and the pump chamber is sealed thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump for delivering an object to be conveyed between two gears meshing with each other and a casing surrounding the gears. More specifically, the present invention relates to a gear pump suitable for use in sequentially sucking and discharging a compressive fluid such as air and an incompressible fluid such as water.

[0002]

2. Description of the Related Art As shown in FIGS. 5 and 6, a conventional gear pump includes a pair of gears 101 and 102 meshing with each other, an oval casing 103 surrounding the gears 101 and 102, and one gear, for example, a gear. The casing 103 is divided into a suction side chamber 104 and a discharge side chamber 105 by a pair of gears 101 and 102 that mesh with each other. This gear pump sucks fluid from the suction port 106 by the rotation of the pair of gears 101 and 102, and a space 112 between the gears 101 and 102 and the casing 103.
Then, the liquid is discharged under pressure from a discharge port 107 communicating with the other chamber 105. The gears 101 and 102 are formed by shaft moldings 108 and 109 integrated by insert molding or the like.
Alternatively, it has a shaft portion connected in the circumferential direction by a combination of a shaft cut into a D shape and a gear hole portion formed into a D hole shape, and the shaft portions 108 and 109 are provided on the casing 103 side. It is rotatably supported by being fitted in the bearing holes 114. The one gear on the drive side, for example, the shaft 108 of the gear 101 is projected to the outside of the pump chamber and is connected to the motor 113. The gears 101 and 102 have a certain gap between the tooth tip surface 110 and the inner peripheral wall 111 of the casing 103, the gap having a size that does not impair the sealing property according to an object to be pressure-fed (hereinafter, referred to as a transported object). It is installed so as to be formed or to be in sliding contact with the inner peripheral wall 111 of the casing.

The casing 103 surrounding the pair of gears 101, 102 is composed of three members, a first case 103a, a second case 103b and a third case 103c. These three cases 103a, 103
b and 103c are the first and second cases 103a and 103.
They are integrated by being tightened by screws 115, 115 which pass through the fool holes formed in b and are inserted into the screw holes of the case 103c. First case 103
A sealing material having elasticity, for example, an O-ring 116 is interposed between a and the second case 103b, and is tightened in the tightening direction (the matching reference surface 103 of both cases 103a and 103b).
x and 103y are crushed in a direction in which they abut, and sealed to seal the pump chamber. At that time, the screws 115, 1
By assembling the mating reference surface 103x of the first case 103a and the mating reference surface 103y of the second case 103b while compressing the sealing material 116 in the tightening direction of 15, the accuracy of the axial distance of the pump chamber is improved. Has been maintained.

Further, the second case 103b and the third case
The space 103c constitutes a space / reduction gear chamber in which a reduction gear 117 for reducing the rotation of the motor 113 is placed. The reduction gear 11 is provided on the third case 103c.
A gear holding portion 103e for holding the motor 7, etc., a motor surrounding portion 103f surrounding the motor 113, a hole portion (not shown) for taking out the power of the motor 113, and a pump are attached to an external device. At the time of attachment parts 103g and 103g,
Screws 115, 11 surrounding a reduction gear such as the reduction gear 117
The reduction gear surrounding portion 103h to which 5 is attached is integrally formed. A cap 103d is fitted to the open end of the motor surrounding portion 103f to protect the motor 113.

[0005]

However, according to the conventional casing structure of the gear pump, the sealing material 116 having elasticity, such as an O-ring, is used as the mating reference surface 1 for both sides.
Since the pump chamber is sealed by compressing the 03x and 103y in the contacting and tightening directions, if the tightening of the screws 115 and 115 is not uniform, the elastic repulsive force of the sealing material 116 causes One side of the one case 103a floats up, and the bearing 114 provided in the first case 103a is biased to generate noise or affect the suction ability. In addition, the first case 103a
When the tightening between the second case 103b and the second case 103b is loose as a whole, the abutment between the case reference surfaces 103x and 103y becomes incomplete, and the sealing performance of the gear is deteriorated to deteriorate the pump performance. There is a risk of impairing the sealing property itself.

The third case 103c has a gear holding portion 103e, a motor surrounding portion 103f, and a motor 11a.
A hole (not shown) for taking out the power of 3 and the mounting portion 1
03g and 103g and the reduction gear surrounding portion 103h are integrally formed, and the structure is complicated and the difference in wall thickness and the capacity are increased. Therefore, it is easily deformed under the influence of sink marks and deterioration of fluidity during molding,
In particular, there is a problem that it is difficult to obtain the accuracy of the gear holding portion 103e that influences important dimensions such as the axial distance between the pair of gears 101 and 102. Therefore, in some cases, there may be problems such as noise and a decrease in suction amount. Furthermore,
Since the screws 115, 115 are attached and tightened by the reduction gear surrounding portion 103h surrounding the reduction gear 117 or the like reduction gear, the screws 115, 115 are strongly tightened to prevent a seal failure, and thus the case is attached to the case. There is a problem that deformation occurs and the pump performance is easily affected.

Further, as described above, the mating reference plane 103
When the contact accuracy of x and 103y and the position accuracy of the reduction gear are deteriorated, not only noise is generated due to contact between the tooth top of the pump chamber and the casing, but also noise is generated between the reduction gears.

It is an object of the present invention to provide a gear pump which has a casing structure which is easy to obtain accuracy and which is unlikely to cause defective products or noise that significantly deteriorates pump performance.

[0009]

In order to achieve the above object, the invention of claim 1 forms a pump chamber with a first case and a second case and meshes with each other in the pump chamber. In a pump for delivering an object to be conveyed by a driving gear and a driven gear, an elastic sealing material is interposed between both cases, the elastic sealing material being compressed in a direction different from the direction in which the mating reference surfaces of the two cases abut. The pump room is sealed.

The pump according to the second aspect of the invention comprises a third case for forming a reduction gear chamber of the drive gear between the second case and the second case, and a mounting portion for mounting to an external device. The at least fourth case is formed separately from the first and second cases.

[0011]

Therefore, according to the first aspect of the invention, when the pump chamber is formed by the first case and the second case, the mating reference surface of one case is generated by the repulsive force of the elastic seal material of the pump chamber. Is less likely to rise from the reference mating surface of the other case. Therefore, the axial clearance in the pump chamber is maintained accurately.

According to the second aspect of the invention, the function of accommodating the reduction gear and the function of accommodating the drive motor and mounting the pump on the external device are separated and shared by the two cases. That is, in the third case, share only the function of forming a reduction gear chamber that accommodates the reduction gear between the second case and supports the drive shaft that supports and rotates the gear in the pump chamber, The fourth case shares the mounting function when the pump is mounted on an external device. This simplifies the structure of the third case.
Further, the influence of excessive force when the pump is attached to the external device on the gear position accuracy in the pump is reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

1 to 3 show an embodiment of the gear pump of the present invention. This gear pump is composed of a casing 3, a drive gear 1 which is meshed with the casing 3, a driven gear 2 and a motor 4 which is a drive source. A drive shaft insertion for inserting a drive shaft 6 into the center of the drive gear 1 is provided. While forming the hole 5, a rotation support shaft insertion hole 7 for inserting the rotation support shaft 8 is formed in the center of the driven gear 2. The sealing material 9 is the reference mating surfaces 3x and 3y of the first and second cases 3a and 3b.
Is interposed between the cases 3a and 3b so as to be compressed in a direction different from the contacting direction. For example, in the case of the present embodiment, the sealing material is provided between the outer side wall of the cylindrical rib 3p fitted in the circular recess 3q formed around the mating reference surface 3y of the second case 3b and the side wall of the circular recess 3q. 9 is interposed. Then, a direction orthogonal to the direction in which the mating reference surfaces 3x and 3y of both cases 3a and 3b come into contact with each other.
The gears 1 and 2 are compressed in the radial direction.

Here, the casing 3 surrounding the pair of gears 1 and 2 is located below the first case 3a located above the second case 3b located below the first case 3a. It is divided into a third case 3c and a fourth case 3d. A rubber seal material 9 having elasticity, such as an O-ring, is interposed between the first case 3a and the second case 3b to seal the pump case. Further, the length of the cylindrical rib 3p fitted into the circular recess 3q is set to a length with which the mating reference surfaces 3x, 3y and other peripheral butting surfaces abut before the tip of the cylindrical rib 3p abuts the bottom of the circular recess 3q. . As a result, the alignment reference surface 3x of the first case 3a and the alignment reference surface 3y of the second case 3b are butt-assembled with each other to maintain the accuracy of the axial distance of the pump chamber. In addition, by fitting the cylindrical rib 3p and the circular recess 3q, the gears 1 and 2 are radially positioned between the first case 3a and the second case 3b, and the first wall forming the peripheral wall of the pump chamber is formed. The accuracy of the radial clearance between the inner peripheral surface of the case 3a and the gears 1 and 2 is adjusted. It should be noted that a cylindrical inlet port member 10 and a discharge port member 11 are integrally formed on the first case 3a.

On the back side of the second case 3b, a lid plate 13 for sandwiching the lip seal 12 fitted on the drive shaft 6 penetrating the casing 3 with the second case 3b is fixed by caulking or the like. It is provided so as to prevent water and the like from leaking along the drive shaft 6. The shape of the lip seal 12 is not particularly limited, but the drive shaft 6
It has a disk-like shape that is fitted to the above, and has a flange that forms a reservoir for storing the leaked fluid in the peripheral portion.

The second case 3b and the third case 3c constitute a reduction gear chamber for accommodating the gears 14 and 15 for decelerating and rotating the drive shaft 6. One reduction gear 14 is press-fitted onto the drive shaft 6, and the other gear 15 is press-fitted onto the output shaft 16 of the motor 4. The third case 3c includes a gear holding portion 3e that holds the reduction gears 14 and 15, and a motor 4
The hole portion 3i for taking out the motive power and the reduction gear surrounding portion 3h surrounding the reduction gears 14 and 15 are integrally formed.
Then, the reduction gear surrounding portion 3h is provided with screws 17, 17
The through holes 3j and 3j are provided. The motor 4 is fixed to the surface of the gear holding portion 3e opposite to the gear holding surface.

A fourth case 3d is arranged below the third case 3c. In this fourth case 3d,
A motor surrounding portion 3f surrounding the motor 4 and attachment portions 3g and 3g when the pump is attached to an external device,
A fixing portion 3s having screw holes 3k and 3k through which the screws 17 and 17 are fixed is formed.

First to fourth cases 3a, 3b, 3
c and 3d are fool holes 3m of the first case 3a, fool holes 3n of the second case 3b, and fool holes 3j of the third case 3c.
Through the screw holes 3k and 3k of the fourth case 3d.
7 and 17 are tightened by screwing and are integrally connected.

In the present embodiment, the drive gear 1 and the driven gear 2 are spur gears, but the drive gears 1 and the driven gears 2 are not limited to these, and helical gears may be used.

Since the gear pump is constructed as described above, it is possible to assemble the gear pump with high accuracy, and it is possible to pump the object to be conveyed, for example, air and water without noise.

That is, the first case 3a and the second case 3
In the assembly of b, as shown in FIG. 3, first, the sealing material 9 is fitted to the outer periphery of the cylindrical rib portion 3p of the first case 3a. Next, the cylindrical rib portion 3p is attached to the second case 3
It is fitted in the circular concave portion 3q of b. The fitting is performed until the mating reference surface 3x of the first case 3a and the mating reference surface 3y of the second case 3b come into contact with each other. Even in a state where the two mating reference surfaces 3x and 3y are in contact with and in close contact with each other, the tip of the cylindrical rib portion 3p does not abut the second case 3b, and a space 3r is formed between the two members. Therefore, the first case 3a and the second case 3b are fitted with each other with the mating reference surfaces 3x and 3y abutted with each other without a gap. When fitted, the sealing material 9
It is compressed in a direction different from the direction in which the two mating reference surfaces 3x and 3y come into contact with each other, that is, in the direction perpendicular to the direction in which the two mating reference surfaces 3x and 3y come into contact with each other, and functions as a seal.

The fitted first case 3a and second case 3b together with the third case 3c are screw 17,
17 is integrally connected to the fourth case 3d. At that time, the first, second and third cases 3a, 3b, 3c
Is fixed by being screwed into the fourth case 3d by passing the screws 17, 17 through the fool holes 3m, 3n, 3j of the respective cases 3a, 3b, 3c. Therefore,
The second case 3b and the third case 3c are fixed and tightened so as to be sandwiched between the first case 3a and the fourth case 3d.

In the pump thus assembled, the first casing 3a is not lifted up by the sealing material 9, and the mating reference surfaces of the first casing 3a and the second casing 3b are in contact with each other so that the gears 1, 2 The axial clearance of the pump chamber housed in is accurately determined. Also, the third case 3
c is molded separately from the fourth case 3d that houses the motor 4, so that it is not affected by sink marks or deformation during molding. Therefore, the axial distance between the gears 1 and 2 in the pump chamber, the axial distance (height) in the pump chamber, and the like are set accurately. As a result, the pump does not generate noise and the suction volume does not decrease. Further, this pump is attached to an external device by using the attachment portions 3g and 3g. Then, when sucking the transported object such as water, the power of the motor 4 is applied to the output shaft 16 and the reduction gear 1.
5, transmitted to the reduction gear 14, drives the drive gear 1 and also rotates the driven gear 2. By the rotation of the gears 1 and 2, water flows in from the suction port member 10 and is discharged from the discharge port member 11, and functions as a pump.

The above embodiment is one example of the preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, even if the seal material 9 is not an O-ring but a seal material having linear elasticity is used, the seal material 9 is inserted into the circular recess 3q of the second case 3b in advance, and then the first case 3a is fitted. good. Further, as the sealing material 9,
As long as it has elasticity, a metal material or a resin material may be used in addition to the rubber material. Further, the first case 3a may be provided with a circular concave portion, and the second case 3b may be provided with a cylindrical rib portion.

Further, in the above-mentioned embodiment, since both the mating reference surfaces 3x and 3y are planes perpendicular to the axial directions of the gears 1 and 2, the axial precision is easy to obtain. The matching reference surfaces 3x and 3y do not necessarily have to be planes perpendicular to the axial directions of the gears 1 and 2, and diagonal surfaces may be butted against each other. Further, in the embodiment, since the sealing material 9 is compressed in the direction perpendicular to the direction in which the both reference surfaces 3x, 3y contact, the repulsive force of the sealing material 9 causes the both reference surfaces 3x, 3y to rise. Since there is no force at all, the structure is preferable. However, as shown in FIG. 4, the structure in which the compression of the sealing material 9 is slightly deviated from the direction in which the both reference surfaces 3x and 3y contact each other is possible. For example, the entire repulsive force of the sealing material 9 does not directly become the lifting force of the mating reference surfaces 3x and 3y, so that the slightly deviated structure can be said to be a preferable structure as compared with the conventional structure.

In the above embodiment, the second case 3
b and the third case 3c constitute a reduction gear chamber for accommodating the gears 14 and 15 for decelerating and rotating the drive shaft 6, but when the reduction gear is placed in the motor 4 or when deceleration is performed. When unnecessary, the third case 3c may be eliminated and the second case 3b may have the function and structure of the third case 3c.

The mounting portions 3g, 3g and the fixed portion 3s are integrally formed on the fourth case 3d.
The mounting portions 3g and 3g may be separate members according to the mounting target, and may be integrated when assembled.
At times, the mounting portions 3g, 3g may be eliminated altogether, or may be provided in another case, for example, the first case 3a. Further, a motor surrounding portion 3f surrounding the motor 4 is integrally formed in the fourth case 3d. However, the whole or part of the motor surrounding portion 3f may be a separate member, or if necessary, the motor surrounding portion 3f. A structure without 3f may be used.

In the above embodiment, the motor 4 is used as the drive source.
However, another drive source such as a solenoid or a spring may be used as long as it drives the drive gear 1 to rotate. Further, in the present embodiment, the drive gear 1 is the drive shaft 6
However, the drive gear 1 may be provided with an internal gear, and the drive gear 1 may be rotated by the internal gear, which is not shown.

[0030]

As is apparent from the above description, the gear pump according to the invention of claim 1 forms a pump chamber by the first case and the second case, and has a sealing material having elasticity between both cases. Since the pump chamber is sealed by interposing a sealant and compressing the sealing material in a direction different from the direction in which the matching reference surfaces of both cases come into contact with each other, the elastic force of the sealing material causes the matching reference surface of one of the cases. Is less likely to rise from the reference mating surface of the other case. Therefore, the axial clearance in the pump chamber is accurately maintained and the bearing formed in the case is not biased, so that the transported object leaks from the pump chamber or between the gears in the pump chamber or between the gear and the case. Noise is less likely to occur. Further, since the mating reference surfaces of the first case and the second case surely contact each other, instability of tightening is eliminated and dimensional accuracy is stabilized.

According to the second aspect of the invention, in the pump for forming the pump chamber by the first case and the second case, and sending out the object to be conveyed by the driving gear and the driven gear meshing with each other in the pump chamber. The third case that forms a reduction gear chamber of the drive gear between the second case and the second case, and the fourth case that has at least an attachment portion for attaching the pump to an external device are provided. Since the case structure is simple and its size is small, and it is not affected by sink marks during molding or the deterioration of the flow of resin material, the space between the pair of gears in the pump chamber as well as the space of the reduction gear chamber The accuracy can be improved. In addition, the influence on the gear position accuracy in the pump due to excessive force when the pump is attached to an external device or when the respective cases are integrated is reduced. Therefore, the reduction gears are appropriately meshed with each other, and the occurrence of noise is reduced.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view showing an embodiment of a gear pump of the present invention.

FIG. 2 is a central longitudinal cross-sectional view taken along a cross sectional line perpendicular to the cross sectional line shown in FIG. 1 according to an embodiment of the gear pump of the present invention.

FIG. 3 is a diagram illustrating a method of assembling the first case and the second case that form the gear pump of the present invention.

FIG. 4 is a cross-sectional view showing the main parts of another embodiment of the gear pump of the present invention.

FIG. 5 is a schematic configuration diagram showing a conventional gear pump in a sectional view of only a casing.

FIG. 6 is a central longitudinal sectional view of a conventional gear pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive gear 2 Driven gear 3 Casing 3a First case 3b Second case 3c Third case 3d Fourth case 3g Mounting part 3s Fixed part 3x, 3y Matching reference surface 4 Motor (driving source) 9 Having elasticity Seal material 14,15 Reduction gear

Claims (2)

[Claims] 1. A pump in which a pump chamber is formed by a first case and a second case, and an object to be conveyed is sent out by a driving gear and a driven gear that mesh with each other in the pump chamber. A gear pump characterized in that a sealing material having elasticity that is compressed in a direction different from the direction in which the mating reference surfaces of both cases abut is interposed between the cases to seal the pump chamber. 2. A pump in which a pump chamber is formed by a first case and a second case, and the object to be conveyed is sent out by a driving gear and a driven gear that mesh with each other in the pump chamber. And a third case forming a reduction gear chamber of the drive gear with the case, and a fourth case having at least a mounting portion for mounting to an external device. A gear pump characterized by being molded separately from the second case.