KR102636507B1 - Helical gear pump - Google Patents

Abstract

The present invention forms the tooth part and the tooth bottom in a round shape and forms the connection part between the tooth part and the tooth bottom in a straight section, thereby enabling continuous gear engagement, which not only allows smooth discharge of fluid but also reduces noise generation by minimizing pulsation. It relates to a submerged helical gear pump having round gear teeth.
The present invention provides a housing (10) with an inlet (11) and an outlet (12) formed on both sides and a pump chamber (15) inside which the inlet (11) and the outlet (12) communicate, and within the pump chamber (15). In the helical gear pump consisting of a pair of helical gears 20 that are arranged to forcibly transport the fluid flowing in through the suction port 11 toward the discharge port 12, the pair of helical gears 20 have a hitting portion ( The flat cross-sectional shape of the tooth bottom portion 21 and the tooth bottom portion 22 is round, and the connection portion connecting the tooth bottom portion 21 and the tooth bottom portion 22 is formed to have a straight section 23, so that the tooth bottom portion 21 ) and the tooth bottom 22 are in continuous surface contact and geared, and a portion of the inner wall of the housing 10 forming the pump chamber 15 adjacent to the suction port 11 has an inner wall and A gap forming portion 40 is formed to form a certain gap between the gear teeth of the helical gear 20 to prevent the gear teeth from contacting the inner wall, and the pump chamber 15 adjacent to the suction port 11 and the discharge port 12. ) On the bottom surface of the helical gear 20, a first groove 50 and a second groove 55 are formed at a certain depth to reduce the contact area between the side of the helical gear 20 and the housing 10, and the discharge port 12 ) The second groove 55 formed on the side is formed so that its central part is long up to the central part of the pump chamber 15 where the helical gear 20 is engaged, so that it is formed between the tooth base and the tooth base when the helical gears are engaged. It is formed so that the existing fluid can escape, and on one side of the housing 10, there is a pressure control passage 60 in communication with the pump chamber 15 and a piston installation passage 61 in communication with the pressure control passage 60. are formed respectively, and the piston installation passage 61 includes a piston 66 that closes the pressure control passage 60, a spring 67 that provides elastic force to the piston 66 to move it forward, and a spring 67 that provides elastic force to the piston 66 to move it forward. ) A pressure control valve 65 composed of a bolt 68 that is spirally connected to the housing 10 is installed to close the rear side of the piston installation passage 61 while supporting the pressure in the pump chamber 15 at a constant pressure. In the above case, the piston 66 moves backward due to pressure, opening the pressure control passage, and guiding the fluid in the pump chamber 15 to be discharged to the outside, thereby controlling the pressure in the pump chamber 15.

Description

Submerged helical gear pump with round gear teeth

The present invention relates to a helical gear pump with round gear teeth, a submerged helical gear pump that can be used in low-viscosity cutting oil and does not require seals.

Recently, machine tools are widely using medium and high pressure coolant systems to improve chip breaking, tool life, cutting speed, and surface finishing. . Coolant systems are already being applied in countries such as the US and Japan, and are also being used domestically. The scope of application of high-pressure coolant systems is increasing.

middle. The gear pump used in the high-pressure coolant system is composed of a drive gear and a driven gear that are installed with interlocking teeth inside the housing, which consists of a casing and a cover that covers each of the entrances on both sides of the casing. . At this time, the driving gear drives the driven gear and engages with each other to rotate, thereby causing a pumping action.

The above pumping action occurs when the teeth of the gear separate from each other on the inlet side, and a suction chamber is formed between the teeth of the gear, and the volume of this suction chamber is increased by the volume occupied by one tooth, creating a slight vacuum that closes the inlet. Fluid flows in through the gear groove and the outer periphery of the casing and is pressured toward the discharge port. As the teeth of the gear engage on the discharge port side, the volume is reduced and the compressed fluid is discharged through the discharge port. To explain in more detail, a gear pump is a pump gear consisting of two driving gears and a driven gear that mesh with each other, placed in a casing circumscribed thereto, and rotating the gear to form a space between the grooves of the teeth and the surrounding wall. It consists of a pumping unit structure to flow fluid through movement.

Conventionally, a typical gear pump has a structure in which a driving gear and a driven gear rotate in engagement with each other inside a casing in which an inlet and an outlet are formed, and a driving shaft and a driven shaft are provided at the center of each of the driving gear and the driven gear. At this time, when power is transmitted to the drive shaft by a drive means (motor, etc.) and the drive gear rotates, the driven gear meshed with the drive gear rotates to perform a pumping action.

There are two types of general gear pumps: those that use straight spur gears and those that use spiral helical gears.

Spur gears are easy to cut, and it is easy to measure the finished dimensions of the teeth, which has the advantage of producing high-precision gears. However, spur gears are accompanied by a negative effect called confinement phenomenon of the fluid, and this confinement phenomenon becomes more noticeable as the viscosity, suction pressure, and discharge pressure of the fluid being transported increases.

On the other hand, the use of helical gears is increasing recently because the pressure change of the transported fluid is not rapid and the meshing of the gears is relatively smooth, so noise and vibration are suppressed. In particular, helical gears are widely used in pumps for pumping high-pressure, high-viscosity fluids such as molten resin, and setting the torsion angle (helical angle) to an appropriate size prevents the confinement phenomenon that occurs in spur gears. It can be minimized.

However, in the case of helical gears, the confinement phenomenon could not be completely eliminated, so although they were better than spur gears, they were not able to dramatically reduce vibration or noise caused by pulsation. Gear pumps using helical gears do not move in the axial direction during operation. A load or stress is generated, which increases as the helical angle of the helical gear increases, resulting in a significant load being applied, causing damage or breakage due to friction in the contact area when used for a long period of time.

In addition, in the conventional helical gear pump, the pressure on the discharge port side is relatively high compared to the suction port side, and as the pressure tries to move the helical gear toward the suction port side, the helical gear contacts the inner wall of the housing on the suction port side, generating noise. There is a risk of wear and damage when used for a long time.

On the other hand, it has a structure that can increase the flow rate of the pump room within the housing, as well as a technology that allows smooth movement of fluid to the discharge port and prevents damage or destruction of the pump when the pressure in the pump room is above a certain pressure. Development is needed.

Registered Patent Publication No. 10-2009908 (2019.08.06. Submerged helical gear pump with round gear teeth) Registered Patent Publication No. 10-2348344 (2022.01.04. Gear pump)

The present invention was created to solve the above-mentioned problem, and by forming the tooth part and the tooth bottom in a round shape and forming the connection part between the tooth part and the tooth bottom in a straight section, continuous gear engagement is possible and smooth discharge of fluid is achieved. Not only is this possible, but by eliminating the confinement phenomenon, it is possible to minimize pulsation and reduce noise generation, and by providing a gap forming part on the inner wall of the housing on the intake side to form a gap between the helical gears, contact between the helical gear and the inner wall of the housing is achieved. To provide a submerged helical gear pump with round gear teeth that can prevent friction as well as noise generation due to friction.

In addition, it is designed as a submerged type so that it can be used in environments above medium pressure without using a seal. To improve the durability of the housing, nodular cast iron (FCD450) is used as a material and special heat treatment is applied to improve durability. To provide a submerged helical gear pump having type gear teeth.

In addition, the first groove and the second groove are formed to reduce the contact area between the side of the helical gear and the housing, and also allow the fluid existing between the tooth base and the tooth bottom to escape when the helical gear engages, thereby preventing the confinement phenomenon. The aim is to provide a submerged helical gear pump with round gear teeth to prevent or significantly reduce vibration and noise generation.

The solution of the present invention for solving the above problem is a housing formed with an inlet 11 and an outlet 12 on both sides and a pump chamber 15 inside which the inlet 11 and the outlet 12 communicate. In the helical gear pump consisting of (10) and a pair of helical gears (20) disposed in the pump chamber (15) and forcibly transporting the fluid flowing in through the suction port (11) toward the discharge port (12), In the helical gear 20, the flat cross-sectional shape of the tooth portion 21 and the tooth bottom portion 22 is formed in a round shape, and the connection portion connecting the tooth portion 21 and the tooth bottom portion 22 is a straight section ( 23), so that the tooth portion 21 and the tooth bottom portion 22 are in continuous surface contact and engaged with each other, and the suction port 11 is located on the inner wall of the housing 10 forming the pump chamber 15. ) A gap forming portion 40 is formed on a portion of the inner wall adjacent to the inner wall to prevent the gear teeth from contacting the inner wall by forming a certain gap between the inner wall and the gear teeth of the helical gear 20, and the suction port 11 and On the bottom surface of the pump chamber 15 adjacent to the discharge port 12, a first groove 50 and a second groove 55 are formed at a certain depth to reduce the contact area between the side of the helical gear 20 and the housing 10. ) are formed respectively, and the central portion of the second groove 55 formed on the side of the discharge port 12 is formed long up to the central part of the pump chamber 15 where the helical gear 20 engages. It is formed so that the fluid existing between the tooth part and the tooth bottom can escape when the inter-gear is engaged, and on one side of the housing 10, there is a pressure control passage 60 in communication with the pump chamber 15 and the pressure control passage ( Piston installation passages 61 are formed in communication with 60), and the piston installation passages 61 include a piston 66 that closes the pressure control passage 60, and provides an elastic force to the piston 66 to move it forward. A pressure control valve 65 is installed consisting of a moving spring 67 and a bolt 68 that is spirally connected to the housing 10 to close the rear side of the piston installation passage 61 while supporting the spring 67. When the pressure in the pump chamber (15) is above a certain pressure, the piston (66) moves backward due to the pressure and opens the pressure control passage to guide the fluid in the pump chamber (15) to be discharged to the outside. The pressure is controlled.

At this time, it is preferable that a support plate 30 is installed between the side of the helical gear 20 and the housing 10 to support the thrust received by the helical gear 20 in the axial direction.

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According to the present invention, which consists of the above configuration, the tooth portion and the tooth bottom of the helical gear are formed to be curved in a round shape, so that the locking phenomenon can be prevented by continuously contacting the gear when the gear is engaged, and pulsation is minimized to reduce vibration as well as noise. It has the effect of preventing or minimizing its occurrence.

In addition, by providing a gap forming portion, contact between the helical gear and the inner wall surface of the housing is prevented, thereby preventing friction in advance and noise generation due to friction.

In addition, by forming the first groove and the second groove to form a space through which fluid can escape, it is possible to prevent confinement that may occur during the gear meshing process, thereby preventing vibration and noise. It works.

1 is a perspective view of a submerged helical gear pump with round gear teeth according to the present invention;
Figure 2 is a side cross-sectional view of Figure 1;
Figure 3 is a plan cross-sectional view of Figure 1;
Figure 4 is a state diagram showing the tooth portion, tooth bottom portion, and straight section of the helical gear according to the present invention;
Figure 5 is a state diagram showing a gap forming portion formed on the inner wall of the housing according to the invention;
Figure 6 is a diagram showing the installation state of the support plate according to the present invention;
Figure 7 is a state diagram showing the first groove and the second groove according to the present invention;
Figure 8 is a state diagram showing a pressure control valve installed in the pressure control passage and piston installation passage according to the present invention.

Hereinafter, a helical gear pump according to a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

As shown, the submerged helical gear pump with round gear teeth according to the present invention is a pump using helical gears among gear pumps that transfer fluid from the suction port side to the discharge port side by rotation of gears that mesh with each other.

A submerged helical gear pump with general round gear teeth consists of a housing (10) having a pump chamber (15) and a pair of helical gears (20) installed in the pump chamber (15).

On both sides of the housing 10, a suction port 11 and a discharge port 12 are formed to face each other in a horizontal direction, and the pump chamber 15 is formed inside to communicate with the suction port 11 and the discharge port 12. do.

For convenience of processing and assembly, the housing 10 may be composed of a casing and a cover that covers both entrances of the casing.

The helical gear 20 is accommodated inside the housing 10, engages with each other, and rotates to forcibly transport fluid from the suction port 11 side to the discharge port 12 side. In detail, the helical gear 20 is a pair of the helical gears. (20) Each has a structure in which a gear portion 20a is formed with helical gear teeth, and a shaft portion 20b is formed protruding from both sides of the gear portion 20a.

And, as a main feature of the present invention, both the tooth portion 21 and the tooth bottom portion 22 of the pair of helical gears 20 are formed in a round shape bent at a certain angle, and the tooth portion 21 and The connection portion of the tooth bottom 22 is formed as a straight section 23 of a certain length.

That is, as shown in Figure 4, in the helical gear of the present invention, the tooth portion and the tooth bottom portion are formed in a round shape and the connection portion is formed in a straight section, so that when the gear is engaged, the pair of helical gears 20 are in continuous contact. It is driven.

Therefore, when the helical gear is operated, the gear mesh area is increased compared to the toothed type, and in particular, when the gears are engaged, the straight sections are continuously meshed in close contact with each other, which makes it possible to minimize pulsation through more stable gear mesh. It has the advantage of being able to reduce vibration and reduce noise.

The helical gear of the present invention can be used for cutting oil, and is designed as a submerged type, so it can be used in an environment of medium pressure or higher without using a seal.

Here, in order to improve the durability of the housing 10, ductile iron (FCD450) is applied to the existing aluminum material and manufactured through special heat treatment.

In addition, heliker gears are also subjected to carburizing heat treatment and coating to improve durability.

And in the case of a helical gear, thrust is generated in the direction opposite to the direction of the gear. This thrust creates a strong force between the side of the helical gear, that is, the side of the gear part (20a) and the bottom surface of the pump chamber (15) of the housing (10). Friction occurs.

In this way, a support plate 30 is installed between the side of the helical gear 20 and the housing 10 to support the thrust received by the helical gear 20 in the axial direction.

The support plate 30 supports the side of the helical gear to prevent wear of the contact surface and reduces noise, thereby preventing a decrease in pump performance.

The support plate 30 is formed in a ring shape like a washer, can be made of engineering plastic specialized for chemical resistance and high temperature, and is manufactured to withstand a static load of up to 150Mpa.

As the helical gear tries to move toward the intake port 11 due to the thrust in the opposite direction due to the rotation of the helical gear, the helical gear contacts the inner wall of the housing 10 on the intake port 11 side, causing wear and noise.

To solve this problem, a gap forming portion 40 is formed on a portion of the inner wall of the housing 10 adjacent to the suction port 11 to form a gap between the housing 10 and the helical gear.

Since the gap forming portion 40 is provided, even if a thrust in the opposite direction occurs due to the rotation of the helical gear, there is no possibility of the inner wall of the housing 10 and the gear teeth of the helical gear 20 coming into contact, so that the helical gear and the inside of the housing are protected. It is possible to prevent wall wear at the source, and furthermore, it is possible to solve noise problems caused by contact.

At this time, if the gap forming portion 40 is formed in a too wide range, it will affect the flow rate and pressure of the pump. Therefore, it should be formed in a range that does not affect the flow rate and pressure of the pump.

In addition, a first groove 50 and a second groove 55 are formed at a certain depth on the bottom surface of the pump chamber 15 adjacent to the suction port 11 and the discharge port 12, respectively.

The bottom surface of the pump chamber 15 can be either the upper or lower surface. If the drive motor is located at the upper side depending on the position of the drive motor, the first groove 50 and the second groove (50) are formed on the upper surface of the pump chamber ( 55) is formed, and when the drive motor is located at the lower side, the first groove 50 and the second groove 55 are formed on the lower surface of the pump chamber.

In the attached drawing, the drive motor is shown to be located on the upper side of the housing.

By forming the first groove 50 and the second groove 55, the contact area between the side of the helical gear 20 and the housing 10 is reduced, and the receiving area in the pump chamber 15 is also increased accordingly. This increases the flow rate.

Here, the central portion of the second groove 55 formed on the side of the discharge port 12 is formed long up to the central portion of the pump chamber 15 where the helical gear 20 engages. Therefore, not only does the flow rate on the discharge port 12 side increase compared to the suction port 11 side, but also when the helical gear engages and rotates, it guides the smooth flow of fluid existing between the gear teeth and the gear groove, preventing vibration due to pulsation. and has the advantage of reducing noise.

Meanwhile, the submerged helical gear pump with round gears of the present invention has a structure that not only regulates the pressure in the pump room, but also randomly discharges fluid to the outside to lower the pressure when the pressure in the pump room rises above a certain pressure. there is.

For this purpose, a pressure control passage 60 is formed on one side of the housing 10 in communication with the pump chamber 15, and a piston installation passage 61 is formed in communication with the pressure adjustment passage 60.

A pressure control valve 65 is installed in the piston installation passage 61 to control the pressure while opening and closing the pressure control passage 60.

As shown, the pressure control valve 65 includes a piston 66 provided in the piston installation passage 61, a spring 67 that provides elastic force to the piston 66 to move it forward, and the spring 67. It consists of a bolt 68 that is spirally coupled to the housing 10 to close the rear side of the piston installation passage 61 while supporting the .

Therefore, when the pressure in the pump chamber 15 reaches a certain pressure, that is, when it is more than a set pressure (pressure set according to the spring elastic coefficient), the piston 66 is moved backward by the pressure and the pressure control passage ( 60) is opened to forcibly discharge the fluid in the pump chamber (15). When a certain amount of fluid is discharged and the pressure in the pump chamber falls below the set pressure, the piston moves forward due to the elastic force of the spring and the pressure control oil flows. (60) will be closed. Through this process, the pressure in the pump room is adjusted.

Here, the bolt 68 can be a headless bolt, and the user can arbitrarily change the set pressure by adjusting the elastic value of the spring by adjusting the amount of helical connection of the headless bolt.

According to the present invention configured as described above, a pair of helical gears rotate (by driving the drive motor, the drive gear connected to the drive shaft rotates and the driven gear coupled to the gear rotates), forcing fluid to flow in from the intake port side and force it to the discharge port side. It will be transported.

At this time, the round tooth part and the tooth base are in contact, and the straight sections are geared in close contact with each other, which not only increases the meshing area but also induces stable meshing, preventing the confinement of fluid and minimizing pulsation. It prevents or minimizes vibration or noise.

In particular, a gap formation is formed on the inner wall of the housing on the intake side, preventing the helical gear from contacting the inner wall of the housing as it is pushed toward the intake due to the thrust in the opposite direction due to the rotation of the helical gear, thus preventing friction in advance. This prevents noise from friction.

In addition, since the first groove and the second groove are formed, the fluid existing between the tooth part and the tooth bottom flows out smoothly when the gear is engaged, thereby performing a smooth pumping operation and preventing vibration and noise due to pulsation. It can be minimized.

10: Housing 11: Inlet
12: discharge port 15: pump room
20: helical gear 20a: gear unit
20b: Shaft 21: Chigobu
22: tooth bottom 30: support plate
40: Gap forming part 50: First groove
55: second groove 60: discharge passage
61: Piston installation passage 65: Pressure control valve
66: Piston 67: Spring
68: Fixing bolt

Claims (5)

A housing (10) is formed with an inlet (11) and an outlet (12) on both sides and has a pump chamber (15) inside which the inlet (11) and the outlet (12) communicate, and is disposed within the pump chamber (15) and has an inlet port (10). In the helical gear pump consisting of a pair of helical gears (20) that forcefully transport the fluid flowing in through (11) to the discharge port (12),
In the pair of helical gears (20), the tooth portion (21) and the tooth bottom portion (22) have a round cross-sectional shape, and the connecting portion connecting the tooth portion (21) and the tooth bottom portion (22) is round. It is formed to have a straight section (23), so that the tooth portion (21) and the tooth bottom portion (22) are in continuous surface contact and geared together,
Among the inner walls of the housing 10 forming the pump chamber 15, a certain gap is formed between the inner wall and the gear teeth of the helical gear 20 on a portion of the inner wall adjacent to the suction port 11, so that the inner wall has a gear on the inner wall. A gap forming portion 40 is formed to prevent teeth from contacting,
On the bottom of the pump chamber 15 adjacent to the suction port 11 and the discharge port 12, a first groove 50 is formed at a certain depth to reduce the contact area between the side of the helical gear 20 and the housing 10. and a second groove 55 are formed, respectively, and the central portion of the second groove 55 formed on the side of the discharge port 12 reaches the central part of the pump chamber 15 where the helical gear 20 is engaged. It is formed long enough to allow the fluid existing between the tooth base and the tooth base to escape when the helical gears are engaged.
On one side of the housing 10, a pressure control passage 60 communicating with the pump chamber 15 and a piston installation passage 61 are formed to communicate with the pressure adjustment passage 60, and the piston installation passage 61 ) includes a piston 66 that closes the pressure control passage 60, a spring 67 that provides elastic force to the piston 66 to move it forward, and a piston installation passage 61 while supporting the spring 67. A pressure control valve 65 consisting of a bolt 68 that is threaded to the housing 10 is installed to close the rear side, and when the pressure in the pump chamber 15 is above a certain pressure, the piston 66 is controlled by pressure. A submerged helical gear pump with round gear teeth, characterized in that the pressure in the pump chamber (15) is controlled by opening the pressure control passage while moving backward and guiding the fluid in the pump chamber (15) to be discharged to the outside.
According to paragraph 1,
A submerged helical having round gear teeth, characterized in that a support plate 30 is installed between the side of the helical gear 20 and the housing 10 to support the thrust received by the helical gear 20 in the axial direction. Gear pump.
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