JP2000303967A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance accuracy in molding for a molded piece made of resin, and to reduce noise and vibration generated by the piece in a gear pump employing the molded piece made of resin. SOLUTION: This pump is equipped with a driving side gear 1, a driven side gear 4 driven by the driving side gear, and with a pump body 6 and a pump base 7, having the driving side gear 1 and the driven side gear 4 within a prescribed clearance. In this case, the driving side gear 1 and the driven side gear 4 are formed out of liquid crystal polymer by means of injection molding. This constitution thereby enables resin molding high in accuracy and noise low in sound level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump whose main members are manufactured by resin molding, and more particularly to an improvement in volumetric efficiency by improving the accuracy of a pump and a reduction in pump noise.

[0002]

2. Description of the Related Art A conventional gear pump formed of a resin molded product has been used as a pressurizing pump for household equipment, for example, a toilet seat for washing with hot water. The gear pump has the simplest structure as a positive displacement pump and can be made compact, and the gear, which is an important component, is a component that can be relatively easily manufactured by injection molding of resin. However, like gear pumps used with normal oil pressure, gear pumps made of resin also have the disadvantage of high noise values.In gear pumps used for flush toilet seats, helical gears are used instead of normal spur gears. The method was applied to reduce the noise level. As a material for resin molding of the gear pump, polyphenylene sulfide resin filled with carbon fiber or the like, which has good molding accuracy and excellent slidability, has been used.

[0003]

However, the conventional resin-molded gear pump has the following problems.

When a gear pump is used for a flush toilet seat, the working fluid is water or hot water, and the fluid viscosity is greatly reduced as compared with oil used as a normal working fluid. In the positive displacement pump, when the fluid viscosity of the working fluid decreases, the volume efficiency, which is an index indicating the fluid transfer efficiency of the positive displacement pump, significantly decreases. When the volumetric efficiency decreases, it is necessary to increase the pump rotation speed to secure the same pump flow rate,
This has led to an increase in pump noise. The volumetric efficiency is determined by the clearance inside the pump, and usually needs to be controlled on the order of several μm to several tens of μm. In particular, when a low-viscosity fluid is used as the working fluid, stricter dimensional control is required.

[0005] Ensuring the clearance of this order is a process that requires a lot of man-hours even in the case of dimensional control with a hydraulic pump using a normal metal-worked part. It was difficult to secure. In particular, in resin molding of gears, due to the configuration of the mold, the teeth of the gears are located at some distance from the gate opening for injecting the resin, and a slight concave sink occurs on the tooth surface. When the tooth surface is concave, the gap between the gear contact surface and the outer peripheral portion of the gear with the pump body that houses the gear increases. As a normal power transmission gear, the drive power of the gear pump is sufficiently small, so this sink of the tooth surface does not cause a large problem in the drive operation of the gear. Since the seal surface is formed by the pitch circle with which the gear contacts, and the outer peripheral portion of the gear also forms the seal surface, the sink of the tooth surface directly affects the volumetric efficiency.
According to the results of experiments conducted by the inventor using water, which is a low-viscosity fluid, as the working fluid, the volumetric efficiency was several times smaller when the tooth surface sink was several tens μm than when the tooth surface sink was 10 μm or less. It was found to drop on the order of ten percent. Therefore, in order to secure volumetric efficiency with a fluid having a low viscosity, it has been found that the precision of the gear is particularly important.

In order to ensure a very high level of gear tooth surface accuracy, for example, 10 μm or less, it is important to control the tooth surface sink during injection molding. In ordinary resin materials and resin molding methods,
It was difficult to reduce the sink of the tooth surface to 10 μm or less. Even when using a polyphenylene sulfide resin filled with a high precision carton fiber with a small molding shrinkage, it is difficult to suppress the sink of the tooth surface to within 10 μm,
In particular, in order to improve the volumetric efficiency of the gear pump, it has been a problem to improve the molding accuracy of the gear teeth.

Further, the clearance on the side surface between the gear and the pump body and the pump base accommodating the gear, and the clearance between the tooth tip and the pump body are also important factors for ensuring the volumetric efficiency of the pump. Must be managed on the order of several tens of μm or less. It is difficult to achieve this accuracy including the shape accuracy in the conventional resin molded product, and it has been a problem to secure a gap between the side surface of the gear and the tooth tip on the order of several tens of μm.

Further, the side plate portions of the pump body and the pump base, which face the side surfaces of the gears, are formed to be thin in order to ensure the accuracy of the resin molded product, but the pressure of the pump acts on this portion. Deformation results in a reduction in the capacity of the pump. When reinforcing ribs are erected, as is the case with ordinary resin molded products, sinks occur in the rib components of the side plate parts, and the sinks become leak paths inside the pump, causing a problem that the performance of the pump is reduced. there were.

Further, although the gear pump has a simple structure, it has a disadvantage that the noise value due to the gear contact noise is high, and it is necessary to reduce the noise value due to the tooth surface contact noise. For this reason, while improving the rotation accuracy of the gear, the accuracy of the tooth surface itself is increased to facilitate the contact between the tooth surfaces of the gear,
Alternatively, it has been a problem to realize a configuration for reducing the noise value, for example, by giving the gear material itself a characteristic capable of reducing the generation of contact noise.

When water is used as the working fluid, the lubricating properties of the water itself are low, and the viscosity of the fluid is low. There is a method of filling. Since the grease to be charged is partially discharged from the inside of the pump during the initial operation of the pump, the discharged grease may affect other functional parts connected to the discharge circuit side of the pump. is there. Therefore, it is desirable to minimize the amount of grease filling the pump,
In order to suppress the grease filling amount as much as possible and maintain the pump performance, it was a problem to attach grease thinly and uniformly to the gear tooth surfaces and the sliding surfaces of the pump body and the pump base in the mass production process. .

[0011]

According to the present invention, a driving gear, a driven gear driven by the driving gear, a driving gear and the driven gear are provided. It has a pump body and a pump base accommodated in a predetermined clearance, and the drive side gear and the driven side gear, or the pump body and the pump base are formed by injection molding of a liquid crystal polymer.

According to the above invention, since the liquid crystal polymer has a good resin fluidity and a property of maintaining a crystalline state even in a fluidized state, it can be molded with a small dimensional change during solidification and can be molded with high precision. It is possible to improve the accuracy of the surface itself, to increase the volumetric efficiency of the pump, and to smooth the contact between the tooth surfaces of the gears. Also, due to the vibration damping characteristics caused by the fibrous structure of the liquid crystal polymer,
Since the gear itself can have a characteristic of reducing the contact noise of the gear teeth, a low-noise gear pump can be realized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to a first aspect of the present invention, a driving side gear, a driven side gear driven by the driving side gear, and the driving side gear and the driven side gear are provided with a predetermined clearance. It has a pump body and a pump base to be housed, and the drive side gear and the driven side gear are formed by injection molding of a liquid crystal polymer.

Since the driving side gear and the driven side gear are made of a liquid crystal polymer, dimensional change during injection molding is small and high precision molding is possible. The volumetric efficiency of the pump can be increased, and the contact between the tooth surfaces of the gears can be smoothed. Further, since the gear itself has the characteristic of reducing the abutment sound of the gear teeth due to the vibration damping characteristic due to the fibrous structure of the liquid crystal polymer, a low noise gear pump can be realized.

The invention according to a second aspect is characterized in that, in addition to the first aspect, the pump body and the pump base are made of a liquid crystal polymer.

Further, in addition to the function of the first aspect, the pump body and the pump base are made of a liquid crystal polymer, so that the gears, the pump body and the pump base can be formed with high precision. Since the accuracy of the cylindricity and flatness of the base can be ensured, the volumetric efficiency of the pump can be increased. In addition, since the liquid crystal polymer has the vibration damping characteristics, the noise generated at the tooth surface of the gear is reduced and the noise generated when the gear contacts the pump body and the pump base is suppressed. Furthermore, as the liquid crystal polymer becomes thinner, the bending stiffness is greatly improved due to the self-reinforcing effect due to the arrangement of crystals, and the thin pump body and the side plate of the pump base are suppressed from being deformed by the pump pressure, thereby improving the pump performance. improves.

According to a third aspect of the present invention, in addition to the first or second aspect, the filler of the liquid crystal polymer may be a composition containing carbon fiber and graphite, or a composition containing only carbon fiber and fluororesin, or graphite. It was done.

Since the liquid crystal polymer has a composition containing only carbon fiber and graphite, or carbon fiber and only a fluororesin or graphite, which are carbon or carbon-based fillers having good slidability in water, The slidability and abrasion resistance are greatly improved, and the liquid crystal polymer alone has the disadvantage of high friction coefficient and the problem of sliding characteristics.

According to a fourth aspect of the present invention, there is provided a pump body in which a driving gear, a driven gear driven by the driving gear, and the driving gear and the driven gear are housed with a predetermined clearance. And a pump base,
The pump body is constituted by a thin inner layer member and an outer layer member for accommodating the inner layer member, and the inner layer member is constituted by a liquid crystal polymer.

The pump body has a two-layer structure,
Since the inner layer member made of a resin molded material that accommodates the driving side gear and the driven side gear with a predetermined clearance can be thinned, the shape accuracy and the like can be improved. Particularly, since a liquid crystal polymer having good resin flowability is used for the inner layer member, a highly accurate thin molded product can be obtained. Further, even if the outer periphery of the gear and the inner layer member abut, the inner layer member is elastically deformed, so that an excessive load can be reduced.
The clearance between the outer periphery of the gear and the inner layer member can be set to a minimum, and the volumetric efficiency can be increased.

According to a fifth aspect of the present invention, in addition to the fourth aspect, a buffer member is inserted between the inner layer member and the outer layer member.

Further, in addition to the function of the fourth aspect, the cushioning member is inserted between the inner layer member and the outer layer member, so as to relax.
The noise generated by the contact between the driving side gear and the driven side gear can be effectively reduced. In particular, since the inner layer member may become thinner and may become a resonator, the resonance of the inner layer member can be effectively reduced.

According to a sixth aspect of the present invention, there is provided a pump for accommodating a drive side gear, a driven side gear driven by the drive side gear, and the drive side gear and the driven side gear with a predetermined clearance. Having a body and a pump base, providing a minute uneven portion on a side plate portion of the pump body and the pump base in contact with each side surface of the driving-side gear and the driven-side gear; It is filled with grease.

Since the pump body and the side plate of the pump base are provided with minute irregularities, and the irregularities are filled with water-resistant grease, the grease is held by the irregularities, so that even a small amount of grease is long. Performance can be maintained for a period. Furthermore, the minute uneven portion also constitutes a labyrinth seal portion, and the flow rate leaking from the side of the gear can be suppressed.

According to a seventh aspect of the present invention, there is provided a pump body which houses a driving gear, a driven gear driven by the driving gear, and the driving gear and the driven gear with a predetermined clearance. And a pump base,
A recess is provided in a part of the side surface of the driving gear and the driven gear, and the recess is filled with water-resistant grease.

Since the grease can be reliably held in the concave portions provided in the driving gear and a part of the driven gear, the pump performance can be maintained for a long time.

The invention according to claim 8 is a pump body that houses a driving gear, a driven gear driven by the driving gear, and the driving gear and the driven gear with a predetermined clearance. And a pump base,
An inclined surface is provided on the side surface of the teeth of the driving side gear and the driven side gear, and the inclined surface is filled with water-resistant grease.

Grease can be reliably held on the inclined surfaces of the teeth of the driving gear and the driven gear, and the grease is collected on the side surfaces of the teeth by rotation of the driving gear and the driven gear. Therefore, pump performance can be maintained for a long period of time.

According to a ninth aspect of the present invention, there is provided a pump for accommodating a driving side gear, a driven side gear driven by the driving side gear, and the driving side gear and the driven side gear with a predetermined clearance. Having a body and a pump base, filling the pump body and the pump base with grease, and positively rotating the drive-side gear at low speed;
The grease is evenly adhered to the inner surfaces of the pump body and the pump base, the driving gear and the driven gear, by reverse rotation.

By rotating the gear forward and backward at low speed, grease can be evenly attached to the sliding surface of the gear.

According to a tenth aspect of the present invention, there is provided a pump body for housing a driving gear, a driven gear driven by the driving gear, and the driving gear and the driven gear with a predetermined clearance. And a pump base, wherein grease is applied to the tooth surface of the drive side gear or the driven side gear while rotating the drive side gear at a low speed, and grease is uniformly attached to the tooth surface. It is.

By applying grease directly to the tooth surface of the gear while rotating the gear, even a small amount of grease is evenly spread on the tooth surface, so that the amount of grease applied can be reduced. Further, since the grease is uniformly attached to the tooth surface, the contact noise between the gears is reduced, which is effective in reducing the noise of the gears.

[0033]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a main part of a gear pump according to Embodiment 1 of the present invention. FIG. 2 is a plan view of a main part of the gear pump.

In FIG. 1, reference numeral 1 denotes a driving gear fixed to the driving shaft 3 of the motor 2, and 1a denotes teeth of the driving gear 1. Reference numeral 4 denotes a driven gear, which is rotatably supported by a rotation holding shaft 5 at a position where an appropriate gap between the driving gear 1 and the tooth is maintained. Reference numeral 4a denotes the teeth of the driven gear 4. The driving gear 1 and the driven gear 4 are housed in a pump body 6. The clearance between the outer circumference and the end face direction of the driving side gear 1 and the driven side gear 4 and the pump body 6 is set to a predetermined value. Reference numeral 7 denotes a pump base, and a driving gear 1
The drive shaft 3 is rotatably held, and the rotation holding shaft 5 fixed to the driven gear 4 is held at a predetermined position. Reference numeral 8 denotes a pump mounting member that fixes the motor 2 and the pump base 7 and has a built-in oil seal 9 to seal the drive shaft 3. Reference numeral 10 denotes a suction port provided on the pump body 6, and reference numeral 11 denotes a discharge port similarly provided on the pump body 6.

Next, the operation and the operation will be described. When the drive shaft 3 of the motor 2 rotates and the drive gear 1 rotates, the driven gear 4 also rotates at the same time, causing a volume change in the pump body 6 and causing the pump body 6 to change its volume. Perform the action. In this embodiment, since the drive gear 1 rotates in the direction of the arrow in FIG. 2, the fluid is sucked in from the suction port 10 side and sent out to the discharge port 11 side.

In the gear pump, the volumetric efficiency is determined by the precision of the gear teeth and the precision of the gap between the driving gear 1 and the driven gear 4 and the pump body 6 and the pump base 7.
In this embodiment, the drive-side gear 1 and the driven-side gear 4 are made of a resin molded product of a liquid crystal polymer.
The liquid crystal polymer has a low flow viscosity at the time of injection molding, and the injection pressure sufficiently acts on the teeth 1a and 4a, which are the terminal portions, so that sink due to insufficient filling can be avoided, and since the dissolved resin flows in the liquid crystal state, It is possible to form the driven gear 1 and the driven gear 4 with high precision, with less sink due to crystallization during solidification. In addition, the liquid crystal polymer has a high vibration damping property because the resin itself has a fibrous structure,
The respective teeth 1a, 4 of the driving side gear 1 and the driven side gear 4
The noise due to the contact sound a can be effectively reduced.

(Embodiment 2) In the contents of the present embodiment, the same parts as those in Embodiment 1 are given the same numbers, and the explanation is omitted here.

The difference from the first embodiment is that the pump body 6
The material of the pump base 7 is also formed of a liquid crystal polymer.

Next, the operation and operation will be described. The pump body 6 and the pump base 7 set predetermined clearances in the outer circumferential direction and the side direction of the driving side gear 1 and the driven side gear 4, respectively. Fulfill the function of ensuring. In order to ensure this predetermined clearance, it is necessary to ensure flatness in the pump base 7 and flatness and cylindricity in the pump body 6. In the case of molding with a normal resin material, the shape accuracy is generally about 100 μm, and it has been difficult to achieve the shape accuracy of about 10 μm, which is one digit, which is required for this type of pump. In the case of using a liquid crystal polymer, the resin flows in a liquid crystal state when dissolved, so that sinking due to crystallization during solidification is small, and since the flow viscosity at the time of injection molding is low, the injection pressure sufficiently acts on the terminal portion, It is possible to injection-mold the pump body 6 and the pump base 7 with high precision in shape.

In addition, since the pump body 6 and the pump base 7 are made of a liquid crystal polymer having a good vibration damping property, the noise generated from the meshing between the driving side gear 1 and the driven side gear 4 is also reduced. Transmission can be suppressed, and pump noise can be reduced.

Further, since the pump body 6, the driving gear 1, and the driven gear 4 are made of the same material, a change in clearance due to a change in temperature of the working fluid is small.
Further stable operation is possible.

(Embodiment 3) In the contents of this embodiment, the same parts as those of Embodiment 1 or 2 are given the same numbers,
Here, the description is omitted.

The difference from the first embodiment or the second embodiment is as follows.
The liquid crystal polymer which is the material of the driving gear 1 and the driven gear 4 or the material of the pump body 6 and the pump base 7 is added with only carbon fiber and graphite or carbon fiber and fluororesin or graphite as fillers.

Next, the operation and function will be described. The resin of the liquid crystal polymer itself has a fibrous structure, and the friction coefficient is higher than that of a normal resin material. The abrasion resistance is better than ordinary resins, but the slidability is not so good, and it is desirable to add a material having good slidability. Carbon fiber, graphite, or fluorocarbon resin has excellent slidability, especially carbon fiber and graphite have good slidability in water and abrasion resistance. By adding these materials, the slidability of liquid crystal polymer is improved. can do.

(Embodiment 4) FIG. 3 is a sectional view of a main part of a gear pump according to Embodiment 4 of the present invention. FIG. 4 is a plan view of a main part of the gear pump. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The difference from the first embodiment is that the pump body 16 that houses the driving gear 1 and the driven gear 4 with a predetermined clearance is composed of an outer layer member 17 and a thin inner layer member 18.

The thin inner layer member 18 is configured to provide a predetermined clearance between the driving side gear 1 and the driven side gear 4. The inner layer member 18 and the outer layer member 17 are combined with a slight gap therebetween, and a thin inner layer member 18 is formed.
Are configured such that they do not deform when assembled, and can be easily deformed even when the driving-side gear 1 and the driven-side gear 4 abut against the thin inner layer member 18.

Next, the operation and action will be described. The pump body 16 which requires the clearance accuracy and the shape accuracy is required.
By forming the inner peripheral surface and the bottom surface with a thin inner layer member 18, it is possible to increase the volumetric efficiency of the pump with a molded product having less sink and precision variation during resin molding. In addition, it is conceivable that the outer circumferences of the driving gear 1 and the driven gear 4 wander due to the accumulation of errors at the time of combination and come into contact with the thin inner layer member 18. To reduce the friction torque and improve the torque efficiency. The inner layer member 18 is desirably made of a liquid crystal polymer having characteristics that the molding accuracy is good and the strength can be secured when the molding is made thin.

(Embodiment 5) FIG. 5 is a sectional view of a main part of a gear pump according to Embodiment 5 of the present invention. FIG. 6 is a plan view of a main part of the gear pump. In this embodiment, the same parts as those of the fourth embodiment are denoted by the same reference numerals, and the description is omitted here.

The fourth embodiment is different from the fourth embodiment in that a pump body 16 for accommodating the driving side gear 1 and the driven side gear 4 with a predetermined clearance is constituted by an outer layer member 17 and a thin inner layer member 18. This is the point that the buffer member 19 is inserted between the thin inner layer member 18.

The thin inner layer member 18 is configured to provide a predetermined clearance between the driving gear 1 and the driven gear 4. A buffer member 19 is inserted between the inner layer member 18 and the outer layer member 17. As the material of the buffer member 19, a material having viscoelasticity such as rubber is desirable.

Next, the operation and function will be described. The pump body 1 which requires the clearance accuracy and the shape accuracy is required.
By forming the inner peripheral surface and the bottom surface of 6 with the thin inner layer member 18, it is possible to increase the volumetric efficiency of the pump with a molded product having less sink and precision variation during resin molding. Further, the buffer member 19 suppresses transmission of noise when the driving side gear 1 and the driven side gear 4 come into contact with each other. In addition, since the inner layer member 18 is particularly thin and may become a resonator, the inner (Embodiment 6) FIG. 7 is a sectional view of a main part of a gear pump according to Embodiment 6 of the present invention. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The difference from the first embodiment is that the pump body 20
And the pump base 21 is provided with minute uneven portions 23 on the respective side plate portions 22, and the uneven portions 23 are filled with water-resistant grease (not shown).

Next, the operation will be described. The grease filled in the fine irregularities 23 is restrained by the fine irregularities, and maintains the lubricating action and the effect of properly maintaining the clearance for a long time. Further, the minute uneven portions 23 form a kind of labyrinth seal, and exhibit an effect of preventing leakage of fluid.

(Embodiment 7) FIG. 8 is a sectional view of a main part of a gear pump according to Embodiment 7 of the present invention. FIG. 9 is a plan view of a main part of the gear pump. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The difference from the first embodiment is that a recess 27 is provided on a part of the side surface of the driving gear 25 and the driven gear 26, and the recess 27 is filled with water-resistant grease (not shown).

Next, the operation will be described. The grease 23 filled in the concave portions 27 on the side surfaces of the driving side gear 25 and the driven side gear 26 is restrained by the concave portions 27 and properly maintains the lubricating action and clearance for a long time. In addition to the effect of maintaining the pump performance, the teeth 25a and 26 of the driving gear 25 and the driven gear 26, which are particularly important for maintaining the pump performance,
By filling g with a, the pump performance can be more effectively improved. In addition, the rotation of the driving gear 25 and the driven gear 26 causes grease to be supplied to the respective tips of the teeth 25a and 26a by centrifugal force, thereby improving the reliability of the pump.

(Eighth Embodiment) FIG. 10 is an external view of a main part of a gear of a gear pump according to an eighth embodiment of the present invention. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The difference from the first embodiment is that the side surfaces of the teeth 28a and 29a of the driving side gear 28 and the driven side gear 29
Inclined surface 3 with front open in the direction of rotation of each gear
0 and 31, and further, grease (not shown) is applied to the driving side gear 28 and the driven side gear 2 including the inclined surfaces 30 and 31.
9 was applied to the side surface.

Next, the operation will be described. When the driving gear 28 and the driven gear 29 rotate, each tooth 2
Since the inclined surfaces 30, 31 are provided on the side surfaces of 8a and 29a so that the front surfaces are opened in the rotation direction of each gear,
Grease 23 is constantly collected and filled on the side surfaces of the teeth 28a and 29a, so that lubrication and clearance during rotation of the driving gear 28 and the driven gear 29 can be properly maintained. The teeth 28a and 2 of the inclined surfaces 30, 31
The angle between the side surface 9a and the side surface is desirably 0.1 to 5 degrees in order to secure the volumetric efficiency of the pump. It is possible to configure the inclined surfaces 30, 31 with a mold during resin molding.

(Embodiment 9) This embodiment relates to a method of applying grease used as a means for improving the lubricity inside the pump and improving the volumetric efficiency of the gear pump shown in Embodiment 1 for example. . The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The grease used for filling the inside of the pump is selected from those having water resistance, high viscosity and high adhesion in order to ensure the durability of the grease itself. In the mass production process, this kind of grease is used for sliding surfaces,
It is difficult to apply the coating uniformly to the tooth surfaces of the teeth 1a and 4a of the driven gear 4. In this embodiment, after the pump body 6 and the pump base 7 are filled with grease, the drive side gear 1 is rotated forward and backward at a low speed to uniformly apply grease to the teeth 1a and the teeth 4a and the sliding surface. Is what you do.

It is desirable that the amount of grease charged into the gear pump be minimized in terms of the grease once discharged from the discharge side during operation and from the viewpoint of cost. Can be minimized.

(Embodiment 10) This embodiment is, for example, Embodiment 1.
The present invention relates to a method of applying grease which is used as a means for improving the lubricity inside the pump and increasing the volumetric efficiency with respect to the gear pump described in (1) above, and in particular, applying grease to each tooth of the driving side gear and driven side gear. The present invention relates to an improvement in a coating method. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted here.

The grease used for filling the inside of the pump is selected from those having water resistance, high viscosity and high adhesion in order to secure the durability of the grease itself. In the mass production process, this kind of grease is used for sliding surfaces,
It is difficult to apply the coating uniformly to the tooth surfaces of the teeth 1a and 4a of the driven gear 4. In this embodiment, the grease is supplied to the teeth 1a and 4a of the driving side gear 1 and the driven side gear 4 while the driving side gear 1 is rotated at a low speed. Grease can be spread evenly and grease can be applied uniformly.

Furthermore, it is important for the volume efficiency of the gear pump and the noise generated by the contact of the tooth surface that grease is evenly applied to the tooth surface. Since grease can be evenly applied to the tooth surfaces of the teeth 1a and 4a of the driving gear 4, the contact noise between the gears can be reduced and the noise can be reduced.

[0068]

As described above, according to the first aspect of the present invention,
A drive-side gear, a driven-side gear driven by the drive-side gear, and a pump body and a pump base that house the drive-side gear and the driven-side gear with a predetermined clearance; Since the driven side gear and the driven side gear are formed by injection molding with a liquid crystal polymer, the dimensional change between the driving side gear and the driven side gear during injection molding is small and high precision molding is possible. , The volumetric efficiency of the pump can be increased, and the contact between the tooth surfaces of the gears can be smoothed. Further, since the gear has a vibration damping characteristic due to the fibrous structure of the liquid crystal polymer, the gear itself has a characteristic of reducing the contact sound of the gear teeth, and a low-noise gear pump can be realized.

According to the second aspect of the present invention, in addition to the first aspect of the present invention, the pump body and the pump base are made of a liquid crystal polymer, so that the cylindricity and the flatness of the pump body and the pump base are particularly ensured. And the volumetric efficiency of the pump can be increased. Further, since the liquid crystal polymer has the vibration damping characteristics, the noise generated on the tooth surface of the gear is reduced, and the noise generated when the gear contacts the pump body and the pump base of the pump is suppressed. Furthermore, as the liquid crystal polymer becomes thinner, the bending stiffness is greatly improved due to the self-reinforcing effect due to the arrangement of crystals, and the thin pump body and the side plate of the pump base are suppressed from being deformed by the pump pressure, thereby improving the pump performance. improves.

According to the third aspect of the present invention, in addition to the first or second aspect, the liquid crystal polymer is made of a material filled with carbon fiber, graphite, or fluororesin having excellent slidability. Slidability can be improved. In particular, carbon fiber and graphite have excellent sliding properties in water, and can exhibit excellent characteristics in a pump using water as a working fluid.

According to the fourth aspect of the present invention, a drive side gear, a driven side gear driven by the drive side gear, and a pump accommodating the drive side gear and the driven side gear with a predetermined clearance. A pump body comprising a thin inner layer member and an outer layer member accommodating the inner layer member, wherein the inner layer member is formed of a liquid crystal polymer.
Because of the layer structure, the inner layer member made of a resin molding material that accommodates the driving side gear and the driven side gear with a predetermined clearance can be thinned, and the shape accuracy and the like can be improved. Particularly, since a liquid crystal polymer having good resin flowability is used for the inner layer member, a highly accurate thin molded product can be obtained. Further, even when the outer periphery of the gear and the inner layer member are in contact with each other, the inner layer member is elastically deformed, so that an excessive load can be reduced, so that the clearance between the outer periphery of the gear and the inner layer member can be set to a minimum, Volumetric efficiency can be increased.

According to the fifth aspect of the present invention, since the buffer member is inserted between the inner layer member and the outer layer member in addition to the fourth aspect of the present invention, it is caused by the contact between the driving side gear and the driven side gear. Noise can be effectively reduced. In particular, since the inner layer member becomes thinner and may become a resonator,
It is possible to effectively reduce the resonance of the inner layer member.

According to the invention of claim 6, a pump body which houses a driving side gear, a driven side gear driven by the driving side gear, and the driving side gear and the driven side gear with a predetermined clearance. And a pump base,
Since the pump body and the side plate of the pump base that are in contact with the respective side surfaces of the drive-side gear and the driven-side gear are provided with minute uneven portions, and the uneven portions are filled with water-resistant grease, Is retained in the uneven portion, and the performance can be maintained for a long time even with a small amount of grease.
Furthermore, the minute uneven portion also constitutes a labyrinth seal portion, and the flow rate leaking from the side of the gear can be suppressed.

According to the seventh aspect of the present invention, a pump body for storing a driving gear, a driven gear driven by the driving gear, and the driving gear and the driven gear with a predetermined clearance. And a pump base,
Since a concave portion is provided in a part of the side surface of the driving side gear and the driven side gear, and the concave portion is filled with water-resistant grease, the grease can be reliably held in this concave portion, and the pump performance can be improved for a long time. Can be maintained.

According to the invention of claim 8, a drive side gear, a driven side gear driven by the drive side gear, and a pump accommodating the drive side gear and the driven side gear with a predetermined clearance. Having a body and a pump base,
Since the inclined surface is provided on the side surface of each tooth of the driving side gear and the driven side gear, the inclined surface of the tooth is filled with grease, and lubrication and clearance when the driving side gear and the driven side gear rotate. Can be properly maintained.

According to the ninth aspect of the present invention, a driving body gear, a driven gear driven by the driving gear, and a pump body accommodating the driving gear and the driven gear with a predetermined clearance. And a pump base,
The pump body and the pump base are filled with grease, and the drive side gear is rotated forward and backward at a low speed, so that the inner surfaces of the pump body and the pump base, the drive side gear and the driven side gear are provided with The grease can be spread evenly, and the grease can be evenly attached to the sliding surface.

According to the tenth aspect of the present invention, a driving side gear, a driven side gear driven by the driving side gear,
A pump body and a pump base for accommodating the drive side gear and the driven side gear with a predetermined clearance, and rotating the drive side gear at a low speed while rotating the drive side gear or the driven side gear. Since the grease is applied to the surface, even a small amount of grease is uniformly diffused on the tooth surface, so that the amount of grease applied can be reduced. Further, since the grease is uniformly attached to the tooth surface, the contact noise between the gears is reduced, which is effective in reducing the noise of the gears.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a gear pump according to embodiments 1, 2, 3, 9 and 10 of the present invention.

FIG. 2 is a plan view of a main part of the gear pump.

FIG. 3 is a sectional view of a main part of a gear pump according to a fourth embodiment of the present invention.

FIG. 4 is a plan view of a main part of the gear pump.

FIG. 5 is a sectional view of a main part of a gear pump according to a fifth embodiment of the present invention.

FIG. 6 is a plan view of a main part of the gear pump.

FIG. 7 is a sectional view of a main part of a gear pump according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view of a main part of a gear pump according to a seventh embodiment of the present invention.

FIG. 9 is a plan view of a main part of the gear pump.

FIG. 10 is an external view of a main part of a gear pump according to an eighth embodiment of the present invention.

[Explanation of symbols]

 1, 25, 28 Drive side gear 4, 26, 29 Driven side gear 6, 16, 20 Pump body 7, 21 Pump base 17 Outer layer member 18 Inner layer member 19 Buffer member 22 Side plate portion 23 Uneven portion 30, 31 Slope

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04C 15/00 F04C 15/00 D // B29K 27:12 67:00 103: 04 105: 12 B29L 15: 00 F term (reference) 3H041 AA01 BB02 CC07 CC11 CC15 CC20 DD05 DD15 DD33 3H044 AA01 BB02 CC05 CC07 CC11 CC12 CC14 CC19 DD01 DD03 DD04 DD05 DD21 DD23 DD24 DD28 4F206 AA16 AA24 AB11 AB18 AB25 AC07 AH12 AH81 JA07

Claims (10)

[Claims] 1. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. A gear pump in which the driving gear and the driven gear are formed by injection molding of a liquid crystal polymer. 2. The gear pump according to claim 1, wherein the pump body and the pump base are formed of a liquid crystal polymer by injection molding. 3. The gear pump according to claim 1, wherein the filler of the liquid crystal polymer has a composition containing only carbon fiber and graphite, or carbon fiber and fluororesin, or graphite alone. 4. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. A gear pump in which the pump body comprises a thin inner layer member and an outer layer member for accommodating the inner layer member, and wherein the inner layer member comprises a liquid crystal polymer. 5. The gear pump according to claim 4, wherein a buffer member is inserted between the inner layer member and the outer layer member. 6. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. The pump body and the pump base were provided with minute uneven portions on respective side plate portions abutting on the respective side surfaces of the drive side gear and the driven side gear of the pump base, and the uneven portions were filled with water-resistant grease. Gear pump. 7. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. A gear pump in which a concave portion is provided on a part of the side surface of the driving side gear and the driven side gear, and the concave portion is filled with water resistant grease. 8. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. A gear pump having a configuration in which inclined surfaces are provided on side surfaces of teeth of the driving side gear and the driven side gear, and the inclined surfaces are filled with water-resistant grease. 9. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. Filling the pump body and the pump base with grease, rotating the drive side gear forward and backward at low speed, and rotating the inner surface of the pump body and the pump base and the drive side gear and the driven side gear. A gear pump in which the grease is evenly applied to the gear pump. 10. A driving gear, a driven gear driven by the driving gear, a pump body and a pump base accommodating the driving gear and the driven gear with a predetermined clearance. A gear pump in which grease is applied to the tooth surface of the drive-side gear or the driven-side gear while rotating the drive-side gear at a low speed, and grease is uniformly attached to the tooth surface.