JPH0275783A - Trochoid pump - Google Patents

Abstract

PURPOSE:To prevent lowering of volume efficiency due to leakage of fluid and lowering of mechanical efficiency due to a friction loss between an outer rotor and a housing and to prevent the generation of noise by a method wherein a chamber fronting on the outer peripheral part of the outer rotor of a pump is communicated with an intertooth chamber formed on the inner periphery of the outer rotor. CONSTITUTION:When an intertooth chamber 5 positioned between a suction port 130 and a delivery port 140 is communicated to the suction port 130, the internal pressure of the intertooth chamber 5 (the pressure of an inner peripheral part 42 of an outer rotor 4) is reduced to a low value. The internal pressure of a pressure balance chamber 180 (the pressure of an outer peripheral part 42 of the outer rotor 4) is also reduced to a low value through first and second communicating grooves 191 and 192. By communicating the intertooth chamber 5 with the delivery port 140, the internal pressure of the intertooth chamber 5 is increased to a high value, and the internal pressure of the pressure balance chamber 180 is also increased to a high value. Thus, the pressure of the inner peripheral part 42 of the outer rotor 4 and the pressure of the outer peripheral part 41 can be kept in a balancing state, fluid from the intertooth chamber 5 can be prevented from leakage, and a friction loss between the outer rotor 4 and a housing 100 can be prevented from an increase, resulting in improvement of the volume efficiency and the mechanical efficiency of a pump.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a trochoid pump that supplies fluid pressure to various fluid pressure motors, and in particular, the present invention relates to a trochoid pump that supplies fluid pressure to various fluid pressure motors. It is related to trochoid pumps that perform pumping action by changing volume.

[Prior Art] Conventionally, in trochoid pumps, the number of external teeth on the inner rotor is one less than the number of internal teeth on the outer rotor, so the same number of interdental spaces as the number of internal teeth on the outer rotor are provided on the outer periphery of the inner rotor. and the inner circumference of the outer rotor. In addition, the internal pressure of each interdental space is low when it is in communication with the suction port that suctions low-pressure oil, and high pressure when it is in communication with the discharge port that discharges high-pressure oil. big.

Here, it is desirable for the trochoid pump to be one in which the pressure at the outer circumference of the inner rotor and the pressure at the inner circumference of the outer rotor are in equilibrium at each point on the circumference, from the viewpoint of mechanical efficiency.

However, in the interdental space located between the suction port and the discharge port, pressure fluctuations are extremely severe due to communication with the suction port or communication with the discharge port. It was very difficult to keep the pressure in the area in equilibrium. If this equilibrium state is disrupted, an unbalanced load will be applied to the outer rotor, and the minute gap (outer clearance) formed between the inner periphery of the housing and the outer periphery of the outer rotor will not be maintained properly, resulting in decreased mechanical efficiency and noise generation. It is the cause.

In order to prevent such problems,
In Publication No. 9385 (cited example A), a trochoid pump has a structure in which a communication groove for communicating a discharge port is provided in an outer circumferential groove formed on the outside of an outer rotor, and the same pressure as the discharge pressure is always introduced to the outer circumference of the outer rotor. Are listed.

In Japanese Utility Model Application Publication No. 61-48984 (cited example A), a trochoid pump has a structure in which a small gap (side clearance) formed between a side surface of an outer rotor and a contact surface of a housing that contacts the side surface of the outer rotor is enlarged. Are listed.

In JP-A-61-138893 (cited examples), by forming a through hole passing through in the radial direction to communicate the inner circumferential part and the outer circumferential part of the outer rotor, the pressure is the same as that of the interdental space. A trochoid pump is described that has a structure in which pressure is constantly guided to the outer periphery of an outer rotor.

[Problems to be Solved by the Invention] However, the conventional trochoid pump having the above configuration A has the following problems:
Since the same pressure as the discharge pressure (high pressure) is always guided to the outer circumference of the outer rotor, even when the pressure on the inner circumference of the outer rotor is low when the interdental space communicates with the suction port,
Since the pressure around the outer rotor is high pressure,
The pressure on the outer circumferential portion of the outer rotor and the pressure on the inner circumferential portion of the outer rotor cannot always be kept in equilibrium, which causes a decrease in mechanical efficiency and generation of noise.

Further, since the conventional trochoid pump having the above-mentioned configuration A has a large side clearance, the amount of oil leaking from the interdental space increases overall, resulting in a problem of low volumetric efficiency.

Furthermore, in conventional trochoid pumps with the above two configurations, the size of the through hole is limited in consideration of the reduction in volumetric efficiency and the strength of the outer rotor. It was difficult to maintain equilibrium. The trochoid pumps having the above two configurations are expensive because it is necessary to form a plurality of through holes in the outer rotor. Generally, the outer rotor is formed by sintering, so in order to form a through hole in the radial direction, it is necessary to add a hole drilling process, a deburring process, etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a trochoid pump that can constantly maintain an equilibrium between the pressure on the outer circumference of an outer rotor and the pressure on the inner circumference of the outer rotor.

[Means for Solving the Problems] The trochoid pump of the present invention includes an inner rotor that is rotationally driven by an external force and has a plurality of external teeth, and an outer rotor that has a plurality of internal teeth that mesh with the external teeth of the inner rotor. , a trochoid pump comprising a housing rotatably supporting the outer rotor and having a suction port for sucking low-pressure fluid into the inside, and a discharge port for discharging high-pressure fluid; a chamber facing the outer periphery of the outer rotor located between the discharge ports; and a toothed chamber located between the suction port and the discharge port and formed between the outer periphery of the inner rotor and the inner periphery of the outer rotor. A configuration is adopted in which the chamber is provided with a communication path that communicates the chamber with the chamber.

[Function] The trochoid pump of the present invention has the following two functions due to the above structure.

When the inner rotor is driven one rotation by an external force, the outer rotor, whose inner teeth mesh with the outer teeth of the inner rotor, also begins to rotate.

When the interdental chamber located between the suction port and the discharge port communicates with the suction port due to the rotation of the inner rotor and the outer rotor, the pressure in the interdental chamber becomes low pressure, and the interdental chamber communicates with the discharge port. In some cases, the pressure within the interdental chambers becomes high.

When the pressure in the interdental chamber is low, the pressure in the communication passage is also low, and when the pressure in the interdental chamber is high, the pressure in the communication passage is also high.

Therefore, the pressure in the chamber facing the outer peripheral portion of the outer rotor and the pressure in the interdental chamber are approximately the same pressure and are always maintained in an equilibrium state.

[Effects of the Invention] The trochoid pump of the present invention has the following effects due to the above structure and operation.

The pressure in the chamber facing the outer circumferential portion of the outer rotor and the pressure in the interdental chamber are almost the same pressure and are always maintained in an equilibrium layer.
The pressure on the outer circumference of the outer rotor and the pressure on the inner circumference of the outer rotor can always be maintained in an equilibrium state. For this reason,
It is possible to prevent a decrease in volumetric efficiency due to fluid leakage from the interdental space, a decrease in mechanical efficiency due to friction loss between the outer rotor and the housing, and generation of noise due to interference between the outer rotor and the housing.

[Example] An example of the trochoid pump of the present invention will be described based on the drawings.

1 and 2 show an internal gear type trochoid pump employing a first embodiment of the present invention.

Reference numeral 1 indicates an internal gear type trochoid pump. This trochoid pump 1 is used as an actuator for driving a fan that blows air into a heat exchanger such as an engine radiator, a refrigerant evaporator or a refrigerant condenser in an air conditioner, or a power steering system. It can be used in hydraulic pumps that generate the hydraulic pressure necessary for operation. The trochoid pump 1 can also be used as a variable damping force shock absorber or a height adjustable shock absorber, a hydraulic pump that generates the hydraulic pressure necessary to operate an automatic transmission, or an internal combustion engine, a transmission, etc. It can be used in hydraulic pumps that supply lubricating oil to sliding parts.

The trochoid pump 1 includes a rotating shaft 2 that is rotationally driven by an external force, and an inner rotor 3 that rotates integrally with the rotating shaft 2.
, an outer rotor 4 that meshes with the inner rotor, and a housing 100 that rotatably supports the outer rotor 4.

The rotating shaft 2 has an input section 21 on the right side in the drawing, and an output section 22 on the center thereof. The input section 21 is connected to the housing 1
00, and a pulley 23 is fastened with a bolt 24. The output section 22 includes an inner rotor 3
A spline portion 25 that meshes with the inner rotor 3 is formed to rotate the inner rotor 3 integrally.

The inner rotor 3 is made of wear-resistant material, such as WC-Co.
Made of sintered cemented carbide such as WC-TiC-Co or WC-TiC-Co.
It is arranged in the housing 100 in an eccentric state. A spline portion 32 that fits into the spline portion 25 of the rotating shaft 2 is formed on the inner peripheral portion 31 of the inner port 3 . Further, the outer peripheral portion 33 of the inner rotor 3 is formed by a trochoid curve, and external teeth 34 that mesh with the outer rotor 4 are formed.

Like the inner rotor 3, the outer rotor 4 is made of a wear-resistant material, for example, a sintered cemented carbide such as WC-Co or WC-TiC-Co, and is rotatably supported within the housing 100. The outer peripheral portion 41 of the outer rotor 4 is in sliding contact with the inner peripheral surface 114 of the housing 100. Further, the inner circumferential portion 42 of the outer rotor 4 is formed with a trochoidal curve, and inner teeth 43 that mesh with the outer teeth 34 of the inner rotor 3 are formed.

Here, in this embodiment, the outer teeth 34 of the inner rotor 3
The number of internal teeth 43 of the outer rotor 4 is one less than the number of internal teeth 43 of the outer rotor 4 (for example, the number of internal teeth 43 of the outer rotor 4 is 7).
, and the number of external teeth 34 of the inner rotor 3 is 6). Therefore, the same number of interdental chambers 5 as the number of internal teeth 43 of the outer rotor 4 are formed between the inner peripheral part 42 of the outer rotor 4 and the outer peripheral part 33 of the inner rotor 3.

The interdental chamber 5 is a pump chamber that causes a volume change due to the rotation of the inner rotor 3 and the outer rotor 4 and performs a pumping action.

The housing 100 is a casting of aluminum, aluminum alloy, or the like, and includes a first housing 110 disposed on the left side in the drawing, and a second housing 120 fixed to the right side of the first housing 110 in the drawing.

The first housing 110 forms a screw hole 111 for fastening the second housing 120, and
It has a suction port 130 that sucks low-pressure oil into the interdental space 5 and a discharge port 140 that discharges high-pressure oil.

A slide bearing (metal bush) 112 that rotatably supports the rotating shaft 2 is provided on the inner periphery of the first housing 110. A thrust washer 113 is installed between the inner periphery of the first housing 110 and the rotary shaft 2 to receive the thrust force generated in the axial direction. Further, an outer rotor 4 is provided on the inner peripheral surface 114 of the first housing 110.
The outer circumferential portion 41 of is in sliding contact.

The second housing 120 has a screw hole 122 for fastening to the first housing 110 with a bolt 121.

A slide bearing (metal bush) 123 that rotatably supports the rotating shaft 2 is provided on the inner periphery of the second housing 120. An oil seal 124 that prevents oil from leaking to the outside and a thrust washer 125 that receives thrust force acting in the axial direction are installed between the inner periphery of the second housing 120 and the rotating shaft 2. Here, an O-ring 127 is installed between the joint surface 115 of the first housing 110 and the joint surface 126 of the second housing 120 to prevent oil from leaking out of the storage chamber 150.

The suction port 130 communicates with a suction pipe 131 attached to the first housing 110. The discharge port 140 is the first
A discharge pipe 141 integrally formed in the housing 110 of
It communicates with Low-pressure oil flows in the suction pipe 131, and high-pressure oil flows in the discharge pipe 141.

Therefore, the inner diameter of the suction tube 131 is larger than the inner diameter of the discharge tube 141.

The housing 100 also includes a first housing 110.
and by assembling the second housing 120,
A storage chamber 150, which is a substantially cylindrical space communicating with the suction port 130 and the discharge port 140, is formed.

Inside the storage chamber 150, the rotating shaft 2 passes through the lower part of the drawing from a slightly central position, and the outer rotor 4 and the inner rotor 3 are rotatably fitted. The storage chamber 150 also includes a first lubricating oil passage 160 for lubricating the rotating shaft 2, the metal bushing 112, and the thrust washer 113, and a second lubricating oil passage 160 for lubricating the rotating shaft 2, the metal bushing 123, and the thrust washer 125. It communicates with the oil passage 170.

The first lubricating oil passage 160 includes an oil passage 161 through which high-pressure oil enters from between the right side surface 116 in the figure near the discharge port 140 and the side surface of the inner rotor 3, the rotating shaft 2, and the metal bushing 1.
12 and the oil passage 16 that lubricates the thrust washer 113.
2, an oil reservoir 163 in which oil is temporarily stored, and a return oil passage 164 in which oil is returned to the suction port 130, through which oil sucked into the interdental space 5 by the pump action circulates.

The second lubricating oil passage 170 includes an oil passage 171 through which high-pressure oil enters from between the illustrated left joint surface 126 near the discharge port 140 and the side surface of the inner rotor 3, and a rotary shaft 2, a metal bush 123, and a thrust washer 125. Oil passage 1 to lubricate
72, an oil reservoir 113 that is blocked by an oil seal 124 and temporarily stores oil, and a return oil passage 174 that returns oil to the suction port 130, and these are pumped into the interdental space 5 by a pump action. The sucked oil is circulated.

Furthermore, the housing 100, as also shown in FIG.
A pressure balancing chamber 180 facing the outer circumference 41 of the outer rotor 4 located between the suction port 130 and the discharge port 140, and an interdental chamber 5 located between the suction port 130 and the discharge port 140.
A communication passage 190 is provided for communicating with the pressure balance chamber 180.

The pressure balancing chamber 180 is formed on the inner circumferential surface 114 of the first housing 110 and extends at a position slightly deviated toward the discharge port 140 by an angle θ. Further, the pressure balancing chamber 180 may be extended to a position slightly deviated toward the suction port 130 side, and can be freely provided as long as it faces the outer circumferential portion 41 of the outer rotor 4 between the suction port 130 and the discharge port 140. can be formed.

The communication path 190 includes a first communication groove 191 and a second communication groove 192.
It consists of

The first communication groove 191 connects the interdental chamber 5 and the pressure balance chamber 180.
It is formed on the right joint surface 115 of the first housing 110.

The second communication groove 192 connects the interdental chamber 5 and the pressure balance chamber 180.
It is formed on the left joint surface 126 of the second housing 120.

Here, when the interdental chamber 5 is located between the suction port 130 and the discharge port 140 (moves from the suction stroke to the discharge stroke), the internal volume becomes maximum during one rotation of the inner rotor 3 and the outer rotor 4.

The operation of the trochoid pump 1 of this embodiment will be explained based on the drawings.

When a rotational force is applied to the rotating shaft 2 by an external force, the storage chamber 150
The inner rotor 3 disposed inside also begins to rotate integrally.

As the inner rotor 3 rotates integrally with the rotating shaft 2, the outer rotor 4 also rotates in the same direction. A pumping action is performed by causing a volume change in the interdental chambers 5 of the same number as the number of internal teeth 43 of the outer rotor 4 due to the rotation of the inner rotor 3 and the outer rotor 4. The internal pressure of the interdental space 5 momentarily changes to a low pressure when it communicates with the suction port 130, and momentarily changes to a high pressure when it communicates with the discharge port 140.

At this time, as the outer rotor 4 rotates, the suction port 13
The interdental chamber 5 located between 0 and the discharge port 140 is the suction port 1.
30, the internal pressure of the interdental chamber 5 (pressure of the inner peripheral part 42 of the outer rotor 4) also becomes low pressure, and the internal pressure of the pressure balancing chamber 180 (pressure of the outer peripheral part 41 of the outer rotor 4) also becomes low pressure. The pressure becomes low through the groove 191 and the second communication groove 192.

Further, when the interdental space 5 located between the suction port 130 and the discharge port 140 communicates with the discharge port 140, the interdental space 5
The internal pressure of the pressure balancing chamber 180 (the pressure of the outer circumference of the outer rotor 4) also becomes high through the first communication groove 191 and the second communication groove 192.

As described above, the pressure in the inner circumferential portion 42 of the outer rotor 4 and the pressure in the outer circumferential portion 41 of the outer rotor 4 can be kept in equilibrium at all times. Therefore, it is possible to prevent unbalanced loads from being applied to the outer rotor 4 and to ensure an appropriate outer peripheral clearance at all times, thereby preventing fluid leakage from the interdental space 5 and reducing friction between the outer rotor 4 and the housing 100. Since an increase in loss can be prevented, it is possible to provide a trochoid pump 1 with good volumetric efficiency and mechanical efficiency.

Further, the communication passage 190 is formed in the housing 100, and the housing 100 is often made of cast metal, and the pressure balancing chamber 180, the first communication groove 191, and the second communication groove 192 are also cast out at the same time. is possible and does not require high costs.

Here, the trochoid pump 1 of the present invention in which the dimensions of the pressure balance chamber 180, the first communication groove 191, and the second communication groove 192 are formed as follows, and the conventional trochoid pump 1 in which the pressure balance chamber 180 and the communication path 190 are not formed. The relationship between pump rotation speed and mechanical efficiency for the trochoid pump is shown in the graph of Figure 4.

A-0, 15b, C=c+B However, (d, -d, )/2<c< (di -d,
)/2B=0.02ct, ,θ=(0,1~i,o
)xθ1A; first communication groove 191 and second communication groove 192
Depth b of the outer rotor 4; Width B of the outer rotor 4; Depth C of the pressure balancing chamber 180; Length D of the first communicating groove 191 and the second communicating groove 192; Width θ of the pressure balancing chamber 180; Angle d1 between the center line and the end of the pressure balancing chamber 180 on the side of the discharge port 140; Tip diameter d2 of the inner teeth 43 of the outer rotor 4; Bottom diameter d of the inner teeth 43 of the outer rotor 4; Outer diameter θ of the outer rotor 4; The angle at which the inner rotor 3 and the outer rotor 4 contact when the volume of the chamber 5 is at its maximum.Furthermore, due to the pumping action of the trochoid pump 1, the oil source (not shown) passes through the suction pipe 131 and the suction port 130 to open both chambers. The low pressure oil sucked into 5 is compressed. After that, the trochoid pump 1 moves the discharge pipe 1 from the discharge port 140.
41, high-pressure oil is forcibly fed to a hydraulic actuator or the like.

Furthermore, some of the high pressure oil is stored in the storage chamber 150.
leaks into an oil passage 161 and an oil passage 171 formed between the inner wall surface near the discharge port 140 and both side surfaces of the inner rotor 3. Then, the high-pressure oil flows out into the oil passage 162 and the oil passage 172, and lubricates the metal bushings 112, 123 and thrust washers 113, 125 arranged in the oil passage 162 and the oil passage 172. The oil flowing out from the oil passage 162.172 is transferred to the oil sump 163.1.
The oil is blocked by an oil seal 124 disposed at 73, and then returned to the suction port 130 of the storage chamber 150 through return oil passages 164 and 174. In this way, the first lubricating oil path 1
60 and the second lubricating oil passage 110, the metal bushings 112, 123 and thrust washers 113, 125 are sufficiently lubricated.

In this way, high pressure oil is
By supplying the metal bushings 113 and 125 to the thrust washers 113 and 125, it is possible to create a very simple and compact bearing, and by lubricating the metal bushings 11
2.123 durability can be dramatically improved.

FIG. 5 shows a trochoid pump employing a second embodiment of the present invention.

(The same functional parts as in the first embodiment are given the same numbers.) In this embodiment, the suction port 130 and the discharge port 140 in the first embodiment are symmetrical in shape, whereas the suction port 230 is symmetrical in shape. The shape of the discharge port 240 and the discharge port 240 are asymmetric.

This embodiment also has the same effects as the first embodiment.

FIG. 6 shows a trochoid pump employing a third embodiment of the present invention.

(The same functional parts as in the first embodiment are given the same numbers) The communication passage 190 of this embodiment eliminates the second communication groove 192 and is composed of a first communication well 191 and a pressure equalization chamber 180. .

This embodiment also has the same effects as the first embodiment.

FIG. 7 shows a trochoid pump employing a fourth embodiment of the present invention.

(The same functional parts as in the first embodiment are given the same numbers.) The communication passage 190 of this embodiment eliminates the first communication groove 191 and is composed of a second communication groove 192 and a pressure equalization chamber 180. .

This embodiment also has the same effects as the first embodiment.

FIG. 8 shows a trochoid pump employing a fifth embodiment of the present invention.

(The same functional parts as in the first embodiment are given the same numbers.) The housing 100 of this embodiment is divided into three parts, the first housing 11
0, a second housing 120, and a third housing 200 surrounding the outer rotor 4. A suction port 130 is provided on the inner circumference of the third housing 200.
A pressure equalization chamber 210 is formed facing the outer peripheral portion 41 of the outer rotor 4 located between the discharge port 140 and the discharge port 140 .

For example, by making the third housing 200 of this embodiment made of iron, the outer rotor 4 and the third housing 200
The difference in thermal expansion coefficient between the

Therefore, in this embodiment, the storage chamber 150, the pressure equalization chamber 210, and the communication path 1 are connected between the joint surface 115 of the first housing 110 and the joint surface 211 of the third housing 200.
90 can be prevented from leaking, and furthermore, the six storage chambers 150 and the pressure equalization chamber 210 can be leaked from between the joint surface 126 of the second housing 120 and the joint surface 212 of the third housing 200.
Also, leakage of oil in the communication path 190 can be prevented. 213
．． 214 is an O-ring that prevents oil from leaking within the storage chamber 150, the pressure balancing chamber 210, and the communication passage 190.

[Other Examples] In this example, the suction port and the discharge port of the storage chamber were formed separately, but one opening serves as both the suction port and the discharge port, and the oil sucked from the oil path is passed through the same oil path. A reciprocating type in which the oil is discharged from the oil reservoir, or a type in which the oil sucked from the oil sump is force-fed to the hydraulic circuit and then discharged to the outside of the hydraulic circuit may be used.

In this embodiment, the trochoid pump is used as a hydraulic pump, but the trochoid pump may be used as a various fluid pressure pump for water, air, etc.

In this embodiment, a communication groove is used as the communication path, but a tubular communication path may also be used as the communication path.

In this embodiment, the inner rotor and the rotating shaft are provided separately, but the inner rotor and the rotating shaft may be provided integrally and the inner rotor may be directly driven to rotate.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a trochoid pump employing the first embodiment of the present invention, FIG. 2 is a front sectional view showing a trochoid pump employing the first embodiment of the present invention, and FIG. 3 is a front sectional view showing the trochoid pump employing the first embodiment of the present invention. FIG. 4 is a side sectional view showing the main parts of a trochoid pump employing the first embodiment of the present invention; FIG. The figure is a front cross-sectional view showing a trochoid pump employing the second embodiment of the present invention, FIG. 6 is a side cross-sectional view showing main parts of a trochoid pump employing the third embodiment of the present invention, and FIG. FIG. 8 is a side cross-sectional view showing the main parts of a trochoid pump employing a fourth embodiment of the present invention, and FIG. 8 is a side cross-sectional view showing a trochoid pump employing a fifth embodiment of the present invention. In the figure 1... Trochoid pump 2... Rotating shaft 3...
Inner rotor 4...Outer rotor 5...Interdental space 34...Outer@43...Inner tooth 100...Housing 130...Suction port 140...Discharge port 18
0.210...Pressure balance chamber 190...Communication path 1
91...1st communication groove 192...2nd communication groove

Claims (1)

[Claims] 1) An inner rotor that is rotationally driven by an external force and has a plurality of external teeth; an outer rotor that has a plurality of internal teeth that mesh with the external teeth of the inner rotor; and the outer rotor is rotatably supported. and a housing having a suction port for sucking low-pressure fluid into the interior, and a discharge port for discharging high-pressure fluid, the housing comprising: the housing located between the suction port and the discharge port; a chamber facing the outer periphery of the outer rotor; and a communication passage located between the suction port and the discharge port and communicating the chamber with an interdental chamber formed between the outer periphery of the inner rotor and the inner periphery of the outer rotor. A trochoid pump comprising: