JPH03515B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric gear rotor fuel pump for mounting on a vehicle or vehicle fuel tank and housing both a rotary pump and an electric drive.

[Conventional technology]

Gear rotor fuel pumps driven by electric drives have been used in some vehicles for several years, either as the original device or as a supplement to the original fuel supply system. Pumps and drives are
Often in a common housing, as disclosed for example in US Pat. No. 4,352,641.

Since pumps are often installed in vehicle fuel tanks, the noise factor is extremely important. Pumps under load generate more noise than normal, which can be audible to passengers as a humming noise to the extent that it is noisy. Various pulse dampening devices have been attempted with some success, but because they typically involve materials such as closed cell foam materials or hollow pulse damping chambers of synthetic flexible material, the useful life of these devices is limited by the presence of hydrocarbons. limited by the susceptibility of the material.

Normally, during operation of these pumps, the medium being pumped is in a liquid state and noise is at a minimum level. When the pumping cell is filled into the intake section of the cycle, there are no pores or steam in the pumping chamber when the outlet is opened. However, if pores or steam are present in the pumping chamber when the outlet is opened (cavitation),
The pressure on the outlet side of the outlet can force fluid back through the outlet into the pumping chamber to fill the pores.

The fuel on the outlet side of the discharge port is usually, for example, 1.055 ~
5.625Kg/cm ² (15-80 pounds per square inch)
operating pressure, the reversal of flow through the outlet is very fast and creates an impact noise. In a relatively standard rotary pump, this sequence can occur five times per revolution of the pumping rotor, and becomes very audible at high speeds.

[Problem to be solved by the invention]

It is an object of the invention to provide a pump structure which avoids backflow shocks during cavitation and thus significantly reduces the noise of pump operation under these circumstances.

It can be seen that while one pumping chamber is discharging in a pumping cycle, another chamber is simultaneously admitting fluid. In other words, the intake and exhaust pressure waves are timed with respect to each other, and typically the amount of fluid being pumped out of each cell is the same as the amount being taken in by the other cell.

The object of the invention is to interpose a flexible device above the outlet adjacent to the rotor and to divide the outlet area into several openings and provide a one-way valve on the outlet side of each opening. The objective is to allow the fluid under pressure to escape, but to prevent the fluid under pressure from being forced back into the pumping chamber in the form of cavitation or vapor.

U.S. Patent Nos. 2,650,544 and 2,383,153 disclose seal plates for gear rotor pumps that have the ability to flex against the output fluid and act as one-way relief plates for noise control. I haven't. Although the latter discloses a stub shaft attachment to the inner gear rotor, the sealing disc does not rotate with the inner rotor. Also, U.S. Patent No.
No. 2,787,963 discloses a bias steel plate supporting a gear rotor assembly against starting pressure, which plate is supported by pump outlet pressure after starting.

The concept of a flexible support plate for the pumping element providing at least one side of the pumping chamber and allowing leakage of the pressure liquid to the pressure outlet device in a unidirectional function in the situation of evaporation (cavitation) is an important feature of the present disclosure. It is a characteristic.

[Means for solving the problems of the invention]

To achieve the above objects, the present invention comprises (a) a circumferentially disposed expanding and contracting positive displacement pumping chamber 252A, with a circumferentially extending low pressure inlet region 310, 320, 322; a rotor device 252, 254 having a high pressure outlet region 330 extending circumferentially and spaced circumferentially from the inlet region;
(c) an inlet housing 120 having an inlet passageway 2 provided in the inlet housing 120 directly adjacent one side of the rotor device;
92 and an inlet port 3 communicating with said inlet area.
20, and further includes a pump outlet port 291A at the rear end of the outlet area.
4,296 and its 1 side is the above outlet port 20
(d) the inlet housing 120 of the rotor device;
and the outlet ports 204, 29
(e) an outlet housing 122 communicating with the pumping chamber 2 on the other side of the rotor device to form an outlet chamber;
(f) means for closing said rotor on one side and directly facing said rotor on said outlet housing 122 on the other side;
includes a flexible resilient sealing plate 260 having a flexible periphery terminating radially outwardly of the pumping chamber 252A, the periphery being responsive to the higher pressure of the outlet region. (g) being able to move away from the rotor arrangement against the pressure of the outlet housing 122 while also serving to prevent backflow of pressurized liquid from the outlet housing 122; A thin flexible auxiliary seal plate 300 is inserted between the 1 side of the child device and the face plate portion 291A, and this auxiliary seal plate 30
0 aligns with the inlet port 320 and the inlet area; the inlet opening 310 and the outlet port 2;
04,296 and a closure portion covering the shallow recess 330;
This allows the pumping chamber 252 in the outlet area to
The hydraulic pressure exerted on A moves into the shallow recess 300 of the auxiliary sealing plate 300 to allow pressurized fluid to reach the outlet opening while the pressurized liquid moves from the outlet port to the upstream portion of the outlet region. It is an object of the present invention to provide a rotary pump for pumping volatile liquids, which is characterized in that it acts to prevent backflow of volatile liquids.

[Effect]

A flexible, resilient sealing plate 260 allows pressurized fluid to move through the circular opening and armature chamber to the outlet passageway 164. The flexible disk prevents pressure from acting adversely on the pump chamber. The flexible seal plate 300 also normally seals the inlet housing 120 to the ring 122 at the face plate portion 291A and has an arcuate opening 310 that allows fuel to enter the pump rotor. This disc also covers a shallow recess 330 (FIG. 11) that opens into the normal exit ports 296, 204. If excessive pressure develops on the pressure side of the rotor, the seal plate 300 is moved outward to allow the pressurized fluid to reach the outlet passage relatively quickly during rotation, and also to prevent pressurization if there is cavitation in the pump chamber. It works to prevent fluid backlash. This assists the seal plate 260 and achieves quiet operation of the pump.

〔Example〕

One embodiment of the present invention is shown in FIGS. 1-11.

Referring first to FIG. 1, a typical assembly of a gear rotor pump will be described. A molded inlet housing 120 includes a reduced diameter flange 12 that is telescopically fitted into one end of a flux ring 126.
The cam ring 12 is an outlet housing with 4
It is in contact with 2. At the other end of flux ring 126 is an outlet end housing 128. Inlet housing 120 and outlet end housing 128
each have opposing shoulders against which a sealing ring 130 is disposed and an outer metal shell 13.
It is held in place by the radially inwardly bent ends 132, 134 of 6.

In FIG. 1, a cylindrical drive projection 14 is shown at one end.
2 and having narrow protruding fingers 144 circumferentially spaced thereabout. The other end of this assembly 140 has a commutator disk 1
There are 46.

The commutator end armature shaft 160 is received in a central recess 162 in the outlet end housing 128. The outlet end housing 128 has a one-way spring loaded outlet valve 1
Outlet mounting bracket 166 made by Shinchiyu that supports 68
It has an axially extending passageway 164 that is coupled to the pump and serves as a pump outlet. This fitting includes an outlet end housing 128 formed of a glass-reinforced plastic that is highly hydrocarbon resistant as are the other plastic parts of the assembly.
molded inside. A threaded outlet bleed adjustment plug 170 is inserted into the recess 1 in the outlet end housing 128.
72 and controls a passageway 174 leading to the interior of the pump assembly. A filter disk 176 is positioned in a mouth 178 that connects to passageway 174.

Outlet end housing 128 has an axially extending forked finger 180 for carrying a tension spring 182 (see FIG. 1). These fingers 180 carry semi-circular permanent magnets that surround the armature outside the air holes and form the motor magnetic field.

The inlet housing 120 has an inlet collar 290 that connects the axial fuel inlet passage 29.
2, and this passageway is connected to the pump outlet port 2.
Relief passage 1 opens to passage 196 communicating with 96
94 has an overhang 192. Check valve 19
8 is supported from the rear by a spring 200 held by a press-fitted retainer 202 and is seated at the connecting portion between the relief passage 194 and the connection passage 196. At the center of the inlet collar 290 is a stub shaft 22 carrying gear rotor assemblies 252, 254.
There is a hole 210 for attaching 0.

The cam ring 12 described above in FIGS. 1 and 2
2 has a partial ring portion 124 that interfits with a flux ring 126. This cam ring also has an opening for a headed retaining screw 240. These threaded openings 242 are preferably larger than the threads to allow diametric adjustment of the cam ring relative to the axis of the assembly. FIG. 2 shows the cam ring 122. A triangular washer plate 244 underlies the head of the bolt 240 and applies retaining pressure to the cam ring, holding it firmly against the inlet housing 120. These plates also hold the assembled mediolateral gear rotor.

The cam ring 122 has a large circular opening 250 positioned eccentrically from the basic rotation axis;
This opening is located on the outer gear rotor 2 of the gear rotor pump.
Receive 52. This particular external gear rotor has, by way of example, eleven tooth recesses. The inner gear 254 of the gear rotor assembly is mounted on the stub shaft 220 and has ten teeth formed thereon. A pump chamber 252A is formed between the internal and external gear rotors 254 and 252. The gear 254 has an axial hole 255 spaced around the central axis pin 220 and the drive projection 1
The fingers 144 on 42 are received. A small gap is provided between the fingers 144 and the holes 255 in the rotor 254 to compensate for slight misalignment.

A circular flat sealing plate 260, preferably made of a flexible material, is pressed against the gear rotor assembly. This sealing plate is most effective if it is flexible. 0.13~0.5mm based on the material used
A thickness range of (0.005-0.020") has been found to be good. The material forming the seal plate 260 is preferably a thin metal, more particularly stainless steel, but also some compressed plastic or fiberglass. Fabrics are also good. Friction is significantly reduced by applying a Teflon or similar friction-reducing coating over the plates. This circular seal plate is held firmly against the rotor assembly and It rotates with the solid body, thus forming a good seal, eliminating axial gaps and at the same time producing almost no friction.Behind the sealing plate 260, as shown in FIG. A multi-legged spider spring 262 (fourth
Fig. 5). The ends of the legs 264 are bent in a plane generally parallel to the body portion 263 to form a pressure pad 266. As shown in FIG. 1, the legs of the star or spider spring 262 interfit with the projections 144 and are pressed against the seal plate 260 during assembly of the parts. There is a slight gap between the diameter of the stub shaft pin and the inside diameter of the plastic drive sleeve 142, allowing some angle to exist between the armature shaft and the fixed rotor pin, allowing for coupling in case of slight misalignment. stabilize.

The reinforcing plate 270 shown in FIG. 7 has a central hole 272 along with standoff holes 274 for receiving the projections 144. The periphery of the plate 270 has ten radial fingers 27.
It has 6. This plate is between seal plate 260 and spider spring 262 so that its fingers reinforce the edges of seal plate 260.

The axle pin 220 is attached to the face 13 of the inlet housing 120.
7 and is located in a recess 210 perpendicular to the surface 1
37 by spider springs 262. Thus, there is essentially a cantilevered mounting on shaft 220 to inner gear rotor 254. Outer gear rotor 252 is supported by and rotatable in cam ring 122.

The cylindrical drive projection 142, described above as mounted on the armature assembly, has a central bore 145 that receives and is supported at the distal end of the stub shaft 220. There is some diametric clearance between the bore 145 and the shaft 220 so that the drive projection 142 is rotatably steered on the shaft, but with some allowance for play. This, along with the gap between the drive pin 144 and the drive hole in the rotor 254, compensates for alignment errors of the armature assembly relative to the stub axis.
As previously discussed, some clearance is provided between drive fingers 144 and holes 255 to allow for slight alignment errors. The seal plate 260, which can be made of thin non-corrosive metal or compressed plastic, is flexible enough to provide a sufficient seal to the part, allowing for very accurate machine finishing on this side of the rotor. The need for a positioned housing plate is avoided. Difficult tolerances to the cam ring 122 and gear rotor are also eliminated. The required operating gaps between rigid parts are also eliminated, thereby reducing leakage and manufacturing costs.

The seal plate 260 is shown in elevation in FIG. The plate has a central opening 261 that receives the shaft 220 surrounded by an opening 270 that receives the fingers 144.

In operation, supply fluid through inlet collar 290 enters inlet port 320 into the gear recess between inner and outer gear rotors 254 and 252. Both gear rotors 252 and 254 are connected to armature 1
40, driven by the drive protrusion 142 and the fingers 144 to rotate, and the liquid to the inner gear rotor 2
54 are placed under pressure as they move into the gear recess of outer gear rotor 252. Fluid, such as gasoline, is forced into the outlet 204 (FIG. 1) and routed around the inner gear rotor 252 to the armature chamber and outlet housing mouth 164.

There is some outer clearance between the cam ring 122 and the outer shell 136 so that the head screw 240 (second
The ring can be moved relative to the screw before tightening (Fig.). There must be some clearance between the teeth of the inner rotor gear and the teeth of the inner rotor gear at a point directly across from the area where the teeth mesh. This gap is typically 0.013~0.076mm (0.0005~
0.003"). The clearance can be adjusted by movement of the cam ring that steers the outer rotor gear. The objective is to keep the tip clearance to a minimum and ensure that the pressurized fluid is not removed from the pressure side of the pumping system. Once this is set, screw 240 is tightened and the parts remain in proper relationship.

Flexible elastic seal plate 2 with noise reduction function
Fulfilled by 60. In the event of cavitation (steam) in the pump on the outlet side, this seal plate 260 prevents the outlet pressure from penetrating back into the pump cavity. During solid fuel pumping, the periphery of the seal plate 260 flexes to direct the fuel to the outlet. However, seal plate 260 forms a barrier to prevent outlet pressure from reaching the pump chamber, which may contain steam rather than solid fuel. The noise during operation of the pump, especially in warm climates, is therefore significantly reduced.

Pump rotor devices 252, 254 operate with expanding and contracting pumping chamber 252A. There is a circumferential inlet region 310, 320, 322 and a circumferential outlet region 330 in each circumferentially spaced from each other. The contracting chamber in the outlet area is closed on one side of the rotor arrangement and on the other side of the rotor by biasing means which are deflected and allow liquid to flow out in the outlet area. This biasing means prevents outlet pressure from flowing back into the pumping chamber 252A, which is filled with vapor rather than liquid. This has been found to significantly reduce the noise of the operating pump. When these pumps are used for fuel in passenger cars, they are often installed within the fuel tank, so the noise factor is important to ride comfort. In areas of high ambient heat, evaporation of volatile fuels can cause so-called "cavitation" in the pump.
occurs. The present invention aims to minimize the noise normally produced by cavitation.

A thin flexible auxiliary seal shown in the elevation view of FIG. 8 and the end view of FIG. There is a board 300. This auxiliary seal plate 30
0 is preferably of the same material as described in connection with seal plate 260. This auxiliary seal plate 30
0 has a friction reducing function, preferably with a Teflon coating. This auxiliary seal plate 300 also has other functions as described later. This auxiliary seal plate 300 has two diametrically opposed holes 302 for receiving retaining bolts and an edge notch 304 that aligns with the pump outlet port 204 in the inlet collar 290. Relatively long arcuate inlet opening 310
is provided outside the center of the auxiliary seal plate 300, and is slightly reduced from one end 312 to the other end 314. This inlet opening 310 is connected to the gear rotor assembly 252,
254 in the radial direction in the inlet region. A circumferentially short outlet opening 31 opposite the inlet opening 310
There are 6.

Viewing the inlet collar 290 from the outer end as in FIG. 3 shows an arcuate inlet port 320 that also aligns with the inlet opening 310 of the auxiliary seal plate 300 and the inlet area of the gear rotor assemblies 252,254. The inlet collar 290 has an arcuate recess 32 that opens into the inlet port 320 radially approximately twice the dimension of the inlet port 320.
2, and the recess has one of the inlet ports 320.
It extends circumferentially from one end well past the other end of inlet port 320 and is therefore approximately twice the length of inlet opening 310 and inlet port 320 .

Figure 10 shows the inlet collar 29 from the inner pump end.
0 again shows the arcuate inlet port 320. Spaced from the smaller end of the inlet is an outlet port 204.
There is an outlet port 296 extending radially outwardly into the armature chamber through which pump output ultimately reaches the pump outlet passage 164.

Embossed on the pump face of the inlet collar 290 and facing flat against the auxiliary seal plate 300 is a shallow recess 330 terminating in a radial line 332 and circumferentially bounded. Radial line 332
connects to a central circular line 334 terminating in passages 196 and 296.

During operation, the seal plate 260 in the operating pump rotates with the pump rotor in a closed state. However, the pumping chamber 252A opposite the inlet opening 310
When the pressure increases on the pressure side of , fuel pushes seal plate 260 away from outer rotor 252 and enters the motor armature chamber. The outlet opening 316 relieves the pressure in the pumping chamber 252A near the end of the pressure region, thereby reseating the seal plate 260 against the gear rotor so that the fuel in the pumping chamber 252A flows out of the inlet opening 310. Prevent it from reaching the entrance area.

It can be seen that the pressure in the armature chamber against the seal plate 260 in the exit region balances the pressure on both sides of the rotating seal plate 260 to seat it against the gear rotor. The reinforcing plate 270 presses the sealing plate 260 against the gear rotor.

Seal plate 260 has an additional function in that when steam is generated on the pump pressure side (cavitation), the pressure in the armature chamber forces seal plate 260 back onto the rotor and prevents backflow of fuel into pumping chamber 252A. It also has In this manner, the seal plate 2
60 acts as a one-way valve, thus avoiding noise that may otherwise occur during cavitation.

Seal plate 260 rotates with the gear rotor to reduce friction. Seal plate 260 actually rotates with inner gear rotor 254 , with only differential movement of outer gear rotor 252 occurring between outer gear rotor 252 and seal plate 260 . This reduces the power required by the motor, which is important in the case of small gear rotors and limited dimensions. An improved utilization of power is achieved over the actual pumping action of the fuel.

The configuration described above allows the inlet opening 310 and inlet port 320 to extend circumferentially back to the end 312. This is due to the relatively short normally open outlet being provided well away from the inlet end 312. There is therefore no orthogonal flow between the inlet and outlet openings. This extension of the inlet opening 310 is highly desirable in maintaining the intake function for an extended period of time and preventing cavitation in the pump.

The function of the auxiliary seal plate 300 described above supplements the function of the seal plate 260. This auxiliary seal plate 30
0 is thin and flexible and operates in response to the pressure of the fuel in the outlet area of the pump gear rotor. To explain this feature, we first describe lines 330, 332, and 334 and enclosed areas 196 and 296.
Reference is made to the shallow embossed area shown in FIG. 10 delineated by . This part is shown in dotted lines in FIG.

During pump operation, the pressure of the fuel in the arcuate pressure region of the gear rotor acts against the auxiliary seal plate 300, pulling it away from the gear rotor in the area shown in dotted lines in FIG. This deflection is due to the entrance collar 290
Lines 330, 332, 344 of the face plate portion 291A,
Shallow recess 33 defined by 196, 296, etc.
0, and may be extremely small, on the order of 1/several thousandth.

This deflection allows pressurized fuel to reach the conventional outlet opening 316 in the auxiliary seal plate 300. This causes the fuel flowing through the auxiliary seal plate 300 to the outlet to reduce the amount of deflection that the seal plate 260 requires.
The effect of is supplemented. Therefore two seal plates 26
0 and the auxiliary sealing plate 300 complement each other in the production of fluid flow from the arcuate pressure region of the pump and at the same time act as a check valve for this region, thus minimizing backflow in case of cavitation, Pump noise in passenger cars can be substantially reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view taken along the line FIG. 3 of one embodiment of the electrically driven rotary pump of the present invention; FIG. 11 is an outer end view of the inlet housing of the pump assembly as indicated by the arrow; FIG. 4 is an elevational view of the spring used; FIG. 5 is a side view of the spring retainer; and FIG. 6 is a gear pump seal. FIG. 7 is an elevational view of the plate; FIG. 7 is a diagram of a finger plate for reinforcing the edge of the seal plate; FIG. 8 is an elevational view of the auxiliary plate; FIG. 9 is an end view of the auxiliary plate; 11 is an inner end view of the inlet housing of the pump assembly as indicated by arrow X in FIG. 11, and FIG. 11 is a cross-sectional view of the inlet housing taken along line -' in FIG. 3. 120... Inlet housing, 122... Cam ring, 128... Outlet housing, 136... Outer shell, 140... Armature assembly, 160... Armature shaft, 198... Ball valve, 200... Spring, 22
0...Stub shaft, 230...Outlet, 252...Outer gear, 254...Inner gear, 260...Seal plate, 262...Spider spring, 270...Reinforcement plate, 290...Inlet collar, 291A... Face plate portion, 300...auxiliary seal plate, 320...inlet port.

Claims (1)

Claims: 1. (a) a circumferentially extending low pressure inlet region 310, 320, 322 having a circumferentially disposed expanding and contracting positive displacement pumping chamber 252A;
a rotor device 252, 254 having a high pressure outlet region 330 similarly extending circumferentially and spaced circumferentially from said inlet region;
(c) an inlet housing 120 having an inlet passageway 2 provided in the inlet housing 120 directly adjacent one side of the rotor device;
92 and an inlet port 3 communicating with said inlet area.
20, further including a pump outlet port 291A at the rear end of the outlet area.
4,296 and its 1 side is the above outlet port 20
(d) the inlet housing 120 of the rotor device;
and the outlet ports 204, 29
(e) an outlet housing 122 communicating with the pumping chamber 2 on the other side of the rotor device to form an outlet chamber;
(f) means for closing said rotor on one side and directly facing said rotor on said outlet housing 122 on the other side;
a flexible resilient sealing plate 260 having a flexible periphery terminating radially outwardly of the pumping chamber 252A, the periphery being responsive to the higher pressure of the outlet region; (g) being able to move away from the rotor arrangement against the pressure of the outlet housing 122 while also serving to prevent backflow of pressurized liquid from the outlet housing 122; A thin flexible auxiliary seal plate 300 is inserted between the 1 side of the child device and the face plate portion 291A, and this auxiliary seal plate 30
0 aligns with the inlet port 320 and the inlet area; the inlet opening 310 and the outlet port 2;
04,296 and a closure portion covering the shallow recess 330;
This allows the pumping chamber 252 in the outlet area to
The hydraulic pressure exerted on A moves into the shallow recess 300 of the auxiliary sealing plate 300 to allow pressurized fluid to reach the outlet opening while the pressurized fluid moves from the outlet port to the upstream portion of the outlet region. A rotary pump for pumping volatile liquids, characterized in that it acts to prevent backflow of liquids.