JP2004052663A - Piston type pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the outside diameter of a piston type pump by preventing a pump part from being projected in a piston type pump. <P>SOLUTION: A plunger 26 connected to a rotating shaft 16 of a motor 9 is slidably disposed in a cylinder 23 fitted to a pump case 21. A pump chamber 32 communicating with the cylinder 23 is formed in the pump case 21. The pump chamber 32 is provided with an inlet 33 and a delivery port 34. An inlet valve 30 having the center offset to the rotating shaft 16 from the center of the inlet 33 is connected to the inlet 33. A delivery valve 47 having the center offset to the rotating shaft 16 from the center of the delivery port 34 is connected to the delivery port 34. The motor 9 and the pump case 21 are accommodated in a housing 2 having a motor storing part 3 and a pump storing art 4 which are formed to have the same outside diameter. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piston type pump, which is a kind of positive displacement pump, and more particularly to a technique which is effective when applied to a vehicle fuel pump driven by a motor.
[0002]
[Prior art]
In a motorcycle, a pump for supplying fuel is usually installed near a fuel tank. In recent years, in order to supply fuel at a high pressure such as 800 kPa, a piston type pump (piston pump), which is a type of positive displacement pump, has been used as this pump. FIG. 11 is a sectional view of a conventional fuel supply piston pump. As shown in FIG. 11, the piston pump 71 includes a pump section P and a motor section M, and the plunger 73 moves up and down in the cylinder 74 as the motor 72 rotates. When the plunger 73 is lifted, the intake valve 75 on the left side in the figure is opened, the discharge valve 76 on the right side in the figure is closed, and fuel is introduced from the intake port 77 into the pump chamber 78. When the plunger 73 is lowered, the suction side valve 75 is closed and the discharge side valve 76 is opened, and the fuel in the pump chamber 78 is supplied from the discharge port 79 to the engine side.
[0003]
[Problems to be solved by the invention]
Here, in the conventional piston pump 71 as shown in FIG. 11, the center of the discharge port 79 and the centers of both valves 75 and 76 are set so as to form the fuel flow path linearly. However, if such a structure is adopted, as shown in FIG. 11, the pump portion P must be installed so as to protrude from the outer diameter of the motor portion M, and the outer diameter of the entire piston pump 71 increases. There was a problem.
[0004]
In recent years, in motorcycles, the fuel pump is often modularized and installed in a fuel tank, and the pump itself has been required to be reduced in size so that it can be installed from a small service hole in a small fuel tank. I have. For this reason, if the pump part P protrudes as shown in FIG. 11, it is difficult to use it as an in-tank type fuel pump, and its improvement has been demanded.
[0005]
An object of the present invention is to eliminate the protrusion of a pump section in a piston pump and reduce the outer diameter of the piston pump.
[0006]
[Means for Solving the Problems]
The piston pump according to the present invention is connected to a rotating shaft of a motor, and is provided with a plunger slidably provided in a cylinder attached to a pump case, and provided in the pump case in communication with the cylinder, A pump chamber in which a port and a discharge port are formed, connected to the suction port, a suction side valve having a center offset from the center of the suction port toward the rotating shaft, and connected to the discharge port. A discharge-side valve whose center is offset from the center of the discharge port on the rotation axis side, a motor housing for housing the motor, and a motor housing having the same outer diameter as the motor housing. And a housing including a pump housing portion in which the pump case is housed.
[0007]
In the present invention, since the suction-side valve and the discharge-side valve are offset from the suction port and the discharge port of the pump chamber on the rotating shaft side of the motor, the pump section and the motor section are accommodated within the same diameter. The outer diameter of the piston pump can be reduced.
[0008]
In the piston type pump, a first flow path communicating with the discharge port between the discharge port and the discharge side valve, and a first flow path connecting the first flow path and the discharge side valve. A second flow path having a larger diameter than the flow path may be provided. With these channels, the discharge side valve can be easily offset to the rotating shaft side, and the extra seal distance of the cylinder can be taken by the diameter difference between both channels, minimizing fuel leakage from around the cylinder. In addition, the pump efficiency is improved.
[0009]
Further, in the piston type pump, a notch may be formed at the pump chamber side end of the cylinder so as to face the suction port and the discharge port, respectively. Further, a notch similar to the notch may be provided at an end of the cylinder opposite to the pump chamber in correspondence with the notch.
[0010]
Further, in the piston type pump, the suction side valve is disposed in an inlet cover attached to the housing outside the pump case, and an inflow port communicating with the outside of the inlet cover is provided at one end side, and the inflow port is provided inside. A cylindrical valve holder in which a valve chamber communicating with the inflow port is formed, a ball housed in the valve chamber and capable of closing the inflow port, and the pump case side formed facing the opening of the valve chamber; A collision seat surface against which the ball abuts when the suction side valve is opened, an annular flow channel formed around the collision seat surface along an opening outer edge of the valve chamber and communicating with the valve chamber; It is good also as composition which has an inflow way which connects between a channel and the above-mentioned suction opening.
[0011]
In the intake side valve, the fuel in the valve chamber flows around the ball, is introduced into the annular flow channel, and reaches the inflow path. At that time, the ball moves without offset and comes into contact with the collision seating surface. Therefore, the ball does not block the inflow path, and the flow path cross-sectional area is increased by the annular flow path groove. Therefore, it is possible to prevent an increase in suction resistance when the valve is opened, and to further reduce the suction resistance. . In addition, the reciprocating motion of the ball is performed smoothly and collision with the inner wall is suppressed, so that wear of the inner wall is also suppressed, and problems of suction resistance and inner wall wear when the suction side valve and the suction port are arranged offset are solved. .
[0012]
Further, in the piston pump, the discharge port communicates with the motor accommodating portion via the discharge side valve, and is formed on an outlet cover attached to the motor accommodating portion side of the housing, and is formed outside the housing. And the fluid discharged from the discharge port may flow through the housing and flow out of the housing from the discharge port. This allows the fluid to flow through the motor accommodating portion, thereby improving the efficiency of lubrication of the motor and cleaning of brush abrasion powder. In this case, the motor may be immersed in the fluid discharged from the discharge port.
[0013]
In addition, the piston type pump can be applied to a fuel supply pump of a motorcycle. Since the pump has a smaller diameter than a conventional piston pump, it is possible to install a motorcycle fuel pump, which is conventionally provided outside the fuel tank, in the tank.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a piston pump according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of the piston pump of FIG. The piston pump 1 of the present invention is used as a fuel supply pump for a motorcycle, and is mounted in a fuel tank via a service hole.
[0015]
The piston pump 1 has a configuration in which a motor section M and a pump section P are integrated, and both are accommodated in a cylindrical housing 2. The housing 2 is formed of a magnetic material such as iron, and includes a motor housing 3 that houses the motor M and a pump housing 4 that houses the pump P. The pump housing portion 4 is formed to have the same outer diameter as the motor housing portion 3, and the housing 2 is formed in a cylindrical shape having no irregularities on the outside. An inlet cover 5 and an outlet cover 6 are attached to both ends of the housing 2, respectively. The inlet cover 5 and the outlet cover 6 are made of synthetic resin, and O-rings 7 and 8 are interposed between the housing and the housing 2.
[0016]
The motor unit M is provided with a normal brush motor 9. A plurality of field permanent magnets 11 are fixed to the inner surface of the housing 2, and an armature 12 is rotatably disposed inside the permanent magnets 11. The armature 12 includes a core 14 having a plurality of slots 13 extending in the axial direction, and a winding 15 wound around the slots 13. The armature 12 is fixed to a rotating shaft 16 and is rotatably supported by a bearing 17 of the outlet cover 6 and a bush-shaped bearing 18. A commutator 19 is provided on the right side of the armature 12 in FIG. The commutator 19 is fixed to the rotating shaft 16, and a brush 20 is in contact with the surface thereof. The brush 20 is held in the outlet cover 6 also serving as a brush holder.
[0017]
The pump section P is disposed in the housing 2 adjacent to the motor section M, and the pump section P and the motor section M are separated by a pump case 21. The pump case 21 is formed of aluminum, and is press-fitted and fixed from the left end side of the housing 2. A bearing 18 is attached to the center of the pump case 21, and the rotary shaft 16 protrudes from the bearing 18 toward the pump portion P.
[0018]
A cylinder fixing hole 22 is formed in the pump case 21, and a steel cylinder 23 is press-fitted and fixed. FIG. 3 is a perspective view showing the configuration of the cylinder 23. As shown in FIG. 3, the cylinder 23 is formed in a hollow cylindrical shape, and cutouts 24a, 24b and 25a, 25b of the same shape are provided at the same positions at the upper and lower ends, respectively. In this case, the reason why the same notches are provided at the upper and lower ends is that, when the cylinder 23 is press-fitted into the pump case 21, the position of the lower end side notch (25a, 25b in FIG. 3) is changed to the upper side notch (24a, 24b). ) So that it can be grasped. In addition, the notches 24 and 25 allow the cylinder 23 to be press-fitted in any of the upper and lower directions, so that the directionality of parts is lost and the workability is improved.
[0019]
A metal plunger 26 is inserted into the cylinder 23 so as to be vertically movable in FIG. The plunger 26 is formed of a columnar solid member, and has a semi-circular mounting portion 27 formed at the upper end. The plunger 26 is formed to have a slightly smaller diameter than the inner diameter of the cylinder 23, and is mounted to be slidable up and down inside the cylinder 23. A pin 28 is inserted through the mounting portion 27 and is connected to the rotation shaft 16 of the motor 9 via a piston link 29 made of synthetic resin.
[0020]
FIG. 4 is an explanatory diagram showing a connection structure between the plunger 26 and the rotating shaft 16. As shown in FIG. 4, an eccentric shaft 31 is formed at the tip of the rotating shaft 16. The center of the eccentric shaft 31 is arranged at a position shifted by a distance e from the center O of the rotation shaft. A piston link 29 is provided between the eccentric shaft 31 and the pin 28. When the rotation shaft 16 rotates, the eccentric shaft 31 moves along the circular locus L, and accordingly, the plunger 26 connected to the eccentric shaft 31 by the piston link 29 moves up and down. That is, the plunger 26 is driven by the motor 9, and moves up and down in the cylinder 23.
[0021]
A pump chamber 32 communicating with the inside of the cylinder 23 is formed below the cylinder 23 of the pump case 21. The cylinder 23 press-fitting hole of the pump case 21 is formed deeper than the height of the cylinder 23, and a gap remains below the cylinder 23 in a state where the cylinder 23 is press-fitted, and this forms the pump chamber 32. A suction port 33 and a discharge port 34 are formed in a side wall of the pump chamber 32. The suction port 33 and the discharge port 34 are provided at positions facing each other, that is, at positions separated by 180 °. FIG. 5 is an explanatory diagram showing a state where the cylinder 23 and the pump chamber 32 are viewed from the suction port 33 side. As shown in FIG. 5, the notches 25a and 25b of the cylinder 23 face the suction port 33 and the discharge port 34, respectively. Thereby, a fuel flow path from the suction port 33 to the notch 25a, the pump chamber 32, the notch 25b, and the discharge port 34 is formed.
[0022]
The suction side valve 30 is provided on the suction port 33 side. The suction side valve 30 includes a cylindrical metal valve holder 35 provided in the inlet cover 5 and a metal ball 36 housed in the valve holder 35. The valve holder 35 is press-fitted and fixed in a mounting hole 50 formed in the inlet cover 5. The mounting hole 50 communicates with the inflow passage 37 that opens on the opposite end side of the inlet cover 5. An inflow port 38 is formed at the tip of the valve holder 35. When the valve holder 35 is press-fitted into the mounting hole 50, it communicates with the inflow path 37. The inside of the valve holder 35 is a space, and a valve chamber 39 is formed. A conical valve seat portion 40 is provided on the inlet 38 side of the valve chamber 39. The ball 36 is accommodated in the valve chamber 39, and when the ball 36 comes into contact with the valve seat portion 40, the inflow port 38 is closed and the suction side valve 30 is closed.
[0023]
When the inlet cover 5 is attached to the housing 2, the inner end face of the inlet cover 5 comes into contact with the outer end face of the pump case 21. FIG. 6 is an explanatory diagram showing the configuration of the outer end surface of the pump case 21. As shown in FIG. 6, a collision seat surface 42 is formed on the end face of the pump case 21 so as to face the opening 41 and concentric with the opening 41. An annular flow channel 43 is formed around the collision seat surface 42 along the outer edge of the opening 41. That is, the collision seat surface 42 is formed in a cylindrical shape so as to protrude from the center of the annular channel groove 43. An O-ring groove 44 is formed around the annular flow passage groove 43, and an O-ring 45 is interposed between the inlet cover 5 and the pump case 21.
[0024]
The inflow passage 46 is provided in the annular flow channel 43 to communicate between the annular flow channel 43 and the suction port 33 of the pump chamber 32. The inflow passage 46 is open at the lower part of the annular flow passage groove 43, and the valve chamber 39 is offset from the inflow passage 46 toward the rotating shaft 16. That is, the center O of the suction side valve 30 _V1 Is the center O of the suction port 33 _i Are offset to the inside. This allows the suction side valve 30 to be housed in the cylindrical housing 2 without the suction side valve 30 protruding from the outer diameter of the motor section M as in the piston pump 71 of FIG.
[0025]
In the suction side valve 30, when the plunger 26 rises, the ball 36 is sucked into the pump case 21 and the inflow port 38 is opened. Thereby, the inflow path 37 is opened, and fuel is introduced into the valve chamber 39 from the outside. Here, as shown in FIG. 7A, if there is no annular flow channel 43 on the pump case 21 side and only the inflow passage 46 is open, the fuel flowing into the valve chamber 39 causes the fuel to flow into the valve chamber 39 as shown in FIG. The ball 36 is drawn toward the inflow path 46 as shown in FIG. For this reason, the inflow path 46 is closed by the ball 36, and a problem arises that the suction resistance increases. Further, as shown in FIG. 7B, the ball 36 collides with the inner wall of the valve chamber 39 at that time, so that the reciprocating motion of the ball 36 is not smooth and the inner wall is worn.
[0026]
On the other hand, in the suction side valve 30, an annular flow channel 43 is provided on the pump case 21 side as shown in FIG. For this reason, the fuel in the valve chamber 39 flows around the ball 36 as shown in FIG. 8B, is introduced into the annular flow channel 43, and reaches the inflow channel 46. At this time, the ball 36 moves to the right in the figure without deviation, and abuts against the collision seat surface 42. Therefore, since the ball 36 does not block the inflow path 46 and the flow path cross-sectional area is increased by the annular flow path groove 43, an increase in suction resistance when the valve is opened can be prevented and further reduced. It becomes possible. In addition, since the reciprocating motion of the ball 36 is performed smoothly and collision with the inner wall is suppressed, wear of the inner wall is also suppressed. With this configuration, it is possible to offsetly arrange the suction side valve 30 and the suction port 33 while solving the problems of the suction resistance and the inner wall wear, so that the diameter of the piston pump 1 is reduced.
[0027]
On the other hand, a discharge side valve 47 is provided on the discharge port 34 side of the valve chamber 39. The discharge side valve 47 is provided in the pump case 21, and a cylindrical metal valve holder 49 is press-fitted and fixed in a mounting hole 48 formed in the pump case 21. The mounting hole 48 opens on the motor section M side of the pump case 21 and communicates with the inside of the housing 2.
[0028]
The mounting hole 48 communicates with the discharge port 34 via a first flow path 51 and a second flow path 52 formed in the pump case 21. FIG. 9 is an explanatory diagram showing the relationship between the first flow path 51 and the second flow path 52. As shown in FIGS. 2 and 9, a first flow path 51 is formed from the discharge port 34 along the axial direction, and then the second flow path having a diameter larger than that of the first flow path 51 is formed in an enlarged form. 52 are provided. The first flow path 51 is formed to have the same diameter as the discharge port 34, and the second flow path 52 is formed to have a diameter about 2.5 times the first flow path 51, and has a center O. ₂ Is the center O of the first flow path 51 ₁ (Center O of discharge port 34 _e (Concentric with the rotation axis 16).
[0029]
An inflow port 53 is formed at the tip of the valve holder 49. When the valve holder 49 is pressed into the mounting hole 48, the valve holder 49 communicates with the second flow path 52. At this time, the center O of the inlet 53 _V2 Is O from the center of the second flow path 51. ₂ Are further offset to the rotation shaft 16 side. That is, the center O of the discharge side valve 47 _V2 Is the center O of the discharge port 34 _e Are offset to the inside. Thus, the discharge side valve 47 can be housed in the cylindrical housing 2 without the discharge side valve 47 protruding from the outer diameter of the motor section M as in the piston pump 71 of FIG. In addition, since the discharge side valve 47 is offset from the discharge port 34, it is possible to connect the two with a flow path obliquely between them. However, processing is very difficult, and two flow paths having different diameters are connected. It is easier and cheaper to do.
[0030]
As described above, in the piston pump 1, the pump portion P having both valves 34 and 47 and the motor portion M can be accommodated within the same diameter, due to the offset to the inside of the suction side valve 30. It becomes possible. Therefore, the outer diameter of the piston pump 1 is reduced, and according to the prototype made by the inventors, the outer diameter of the conventional piston pump 71 as shown in FIG. The size could be reduced to about 30 mm. As a result, it has become possible to convert the fuel pump for motorcycles, which has conventionally been installed outside the tank, into an in-tank.
[0031]
Note that it is also possible to connect the discharge port 34 and the discharge-side valve 47 only with the large-diameter second flow path 52 without forming the first flow path 51. However, in this case, the seal distance of the leakage flow path between the cylinder 23 and the cylinder fixing hole 22 is reduced by the second flow path 52. On the other hand, when the first flow path 51 is formed, an extra sealing distance of the cylinder 23 can be provided by a difference in diameter between the two flow paths 51 and 52. In other words, the seal distance between the cylinder 23 and the cylinder fixing hole 22 can be increased by the dimension X in FIG. 2, the fuel leakage from the periphery of the cylinder 23 is minimized, and the pump efficiency is improved.
[0032]
The inside of the valve holder 49 is a space, and a valve chamber 54 is formed. A conical valve seat portion 55 is provided on the inflow port 53 side of the valve chamber 54. A ball 56 is accommodated in the valve chamber 54 and is urged by a valve spring 57 in a direction in which the ball 56 contacts the valve seat portion 55. The valve spring 57 is held by a stopper 59 attached to the opening 58 side of the valve holder 49. When the ball 56 comes into contact with the valve seat portion 55, the inlet 53 is closed, and the discharge side valve 47 is closed.
[0033]
The discharge side valve 47 is closed by the valve spring 57 when the plunger 26 is raised. When the plunger 26 moves down, the ball 56 moves against the urging force of the valve spring 57, and the inlet 53 is opened. Thereby, the first and second flow paths 51 and 52 are opened, and fuel is introduced into the valve chamber 54 from the pump chamber 32. Fuel in the valve chamber 54 is discharged from the opening 58. As described above, in the piston pump 1, the suction side valve 30 is opened by the rise of the plunger 26, and the fuel is introduced into the pump chamber 32. As the plunger 26 is lowered, the fuel is introduced from the discharge side valve 47 side to the motor section M of the housing 2. Sent to the side.
[0034]
The fuel delivered to the motor section M flows through the housing 2 while immersing the armature 12 and the commutator 19 of the motor 9. The fuel in the housing 2 reaches the outlet cover 6 and is supplied to the outside of the housing 2 from a delivery port 61 formed in the outlet cover 6. That is, in the piston pump 1, the inside of the motor housing 3 is also used as a part of the fuel flow path. Therefore, it is possible to arrange the pump section P and the motor section M in series and to house them in the housing 2 without separately providing a fuel flow path. Further, in the piston pump 71 of FIG. 11, the fuel entering the motor side has no outlet and the flow amount is small. However, in the piston pump 1, the supplied fuel flows through the motor housing 3, The supply is also large. Therefore, the efficiency of lubrication of the motor 9 and cleaning of brush abrasion powder is greatly improved as compared with the prior art.
[0035]
The pump case 21 is provided with a communication hole 62 that connects the motor housing 3 and the pump housing 4, and fuel also flows into the pump housing 4. The inflow fuel lubricates between the bearing 18 and the plunger 26 and the cylinder 23, between the piston link 29 and the eccentric shaft 31 and the pin 28, and the like. When the pressure of the fuel flowing into the motor housing 3 is large, the fuel is returned from the relief valve 63 provided in the inlet cover 5 into the fuel tank.
[0036]
The present invention is not limited to the above embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention.
For example, in the above-described embodiment, the suction-side valve 30 and the discharge-side valve 47 are configured by ball valves. However, the shape of the valves is not limited thereto. For example, as illustrated in FIG. A reed valve may be used. In the case of FIG. 10, in the suction-side valve 30, a valve chamber 39 and an inflow passage 37 are formed in the inlet cover 5, and a leaf spring-like valve body 64 made of a metal piece is mounted between them. The valve body 64 is urged in a direction to close the inflow path 37. When the plunger 26 rises, the tip of the valve body 64 moves to the upper right in the figure, and the inflow passage 37 is opened to communicate with the valve chamber 39. When the plunger 26 descends, the tip moves to the left in the drawing, and the inflow passage 37 is closed.
[0037]
On the other hand, in the discharge side valve 47, a valve chamber 54 and a flow path 65 are formed in the pump case 21, and a leaf spring-like valve element 66 made of a metal piece is mounted between them. The valve element 66 is urged in a direction to close the flow path 65. When the plunger 26 descends, the tip of the valve body 66 moves to the upper right in the figure, and the flow path 65 is opened to communicate with the valve chamber 54. When the plunger 26 rises, the tip moves to the left in the figure, and the flow path 65 is closed.
[0038]
Further, in the above-described embodiment, an example is shown in which the piston pump according to the present invention is applied to a fuel supply pump of a motorcycle. However, the application is not limited to this. It can be used as a pump for supplying various fluids such as gas.
[0039]
【The invention's effect】
According to the piston type pump of the present invention, in a pump of a type in which fuel is sucked into a pump chamber by a plunger connected to a rotating shaft of a motor and slidably provided in a cylinder and fuel is discharged from the pump chamber, The side valve and the discharge side valve are arranged offset to the rotary shaft side with respect to the suction port and the discharge port of the pump chamber, so that the pump part and the motor part can be accommodated within the same diameter, and the outer diameter of the piston pump Can be reduced in diameter.
[0040]
Also, a first flow path communicating with the discharge port between the discharge port and the discharge side valve, and a second flow path having a diameter larger than the first flow path connecting the first flow path and the discharge side valve. By providing the passages, the discharge side valve can be easily offset to the rotation shaft side by these flow passages, and the extra seal distance of the cylinder can be provided by the diameter difference between the two flow passages. Fuel leakage is minimized, and pump efficiency is improved.
[0041]
Further, the suction side valve is provided with an inflow port communicating with the outside and a valve chamber formed therein with a valve chamber communicating with the inflow port, a ball housed in the valve chamber and capable of closing the inflow port, and a pump case. A ball collision seat surface formed on the side facing the opening of the valve chamber, an annular flow channel formed in communication with the valve chamber, and an inflow communicating between the annular flow channel and the suction port of the pump chamber. With this configuration, the fuel in the valve chamber flows around the ball, is introduced into the annular flow path groove, and reaches the inflow path, so that the ball moves evenly and comes into contact with the collision seat surface. Therefore, the ball does not block the inflow path, and the flow path cross-sectional area is increased by the annular flow path groove. Therefore, it is possible to prevent an increase in suction resistance when the valve is opened, and to further reduce the suction resistance. . In addition, the reciprocating motion of the ball is performed smoothly and collision with the inner wall is suppressed, so that wear of the inner wall is also suppressed, and problems of suction resistance and inner wall wear when the suction side valve and the suction port are arranged offset are solved. .
[Brief description of the drawings]
FIG. 1 is a sectional view of a piston pump according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of the piston pump of FIG.
FIG. 3 is a perspective view showing a configuration of a cylinder.
FIG. 4 is an explanatory diagram showing a connection structure between a plunger and an output shaft.
FIG. 5 is an explanatory diagram showing a state where a cylinder and a pump chamber are viewed from a suction port side.
FIG. 6 is an explanatory diagram showing a configuration of an outer end surface of the pump case.
FIGS. 7A and 7B are explanatory views showing the operation of the suction-side valve in a case where there is no annular flow channel on the pump case side and only the inflow path is open, wherein FIG. 7A is a valve closed state, and FIG. The state is shown.
FIGS. 8A and 8B are explanatory diagrams showing the operation of the suction side valve when an annular flow channel is provided on the pump case side, wherein FIG. 8A shows a valve closed state and FIG. 8B shows a valve open state; .
FIG. 9 is an explanatory diagram showing a relationship between a first flow path and a second flow path.
FIG. 10 is an enlarged view of a main part of a modification in which the suction side valve and the discharge side valve in the piston pump of FIG. 1 are configured by reed valves.
FIG. 11 is a sectional view of a conventional fuel supply piston pump.
[Explanation of symbols]
1 piston pump
2 Housing
3 Motor housing
4 Pump housing
5 Inlet cover
6 outlet cover
7,8 O-ring
9 Motor
11 Field permanent magnet
12 Armature
13 slots
14 core
15 winding
16 rotating shaft
17 Bearing
18 Bearing
19 commutator
20 brushes
21 Pump case
22 Cylinder fixing hole
23 cylinder
24a, 24b notch
25a, 25b notch
26 plunger
27 Mounting part
28 pins
29 piston link
30 Suction side valve
31 Eccentric shaft
32 pump room
33 suction port
34 Discharge port
35 Valve holder
36 balls
37 Inflow channel
38 Inlet
39 Valve room
40 Valve seat
41 opening
42 collision seat
43 annular channel groove
44 O-ring groove
45 O-ring
46 Inflow channel
47 Discharge side valve
48 Mounting hole
49 Valve holder
50 Mounting hole
51 1st channel
52 Second flow path
53 Inlet
54 Valve room
55 Valve seat
56 balls
57 Valve spring
58 opening
59 Stopper
61 Outlet
62 communication hole
63 relief valve
64 valve body
65 channels
66 valve body
71 Piston pump
72 motor
73 plunger
74 cylinder
75 Suction side valve
76 Discharge side valve
77 Inlet
78 Pump room
79 Discharge port
M Motor part
P pump section
O Center of rotation axis
O ₁ Center of first channel
O ₂ Center of second flow path
O _V1 Inlet valve center
O _V2 Discharge side valve center
Oi Inlet center
Oe outlet center

Claims (8)

A plunger connected to the rotation shaft of the motor and slidably provided in a cylinder attached to the pump case;
A pump chamber provided in the pump case in communication with the cylinder and having a suction port and a discharge port formed therein,
A suction-side valve connected to the suction port, a center of which is arranged offset from the center of the suction port toward the rotation shaft;
A discharge-side valve connected to the discharge port, a center of which is arranged offset from the center of the discharge port toward the rotation axis;
A piston type pump comprising: a motor housing portion for housing the motor; and a housing having a pump housing portion having the same outer diameter as the motor housing portion and housing the pump case therein. 2. The piston type pump according to claim 1, wherein a first flow path communicating with the discharge port and a connection between the first flow path and the discharge side valve are provided between the discharge port and the discharge side valve. And a second flow path having a diameter larger than that of the first flow path. 3. The piston type pump according to claim 1, wherein notches are formed in the pump chamber-side end of the cylinder so as to face the suction port and the discharge port, respectively. 4. The piston pump according to claim 3, wherein a notch similar to the notch is provided at an end of the cylinder opposite to the pump chamber, corresponding to the notch. 5. The piston type pump according to claim 1, wherein the suction-side valve is disposed in an inlet cover attached to the housing outside the pump case. A cylindrical valve holder in which an inflow port communicating with the inflow port is provided and in which a valve chamber communicating with the inflow port is formed, a ball housed in the valve chamber and capable of closing the inflow port, A collision seating surface formed facing the opening of the valve chamber and contacting the ball when the suction side valve is opened, and formed around the collision seating surface and communicating with the valve chamber along the opening outer edge of the valve chamber; A piston-type pump having an annular flow channel formed therein and an inflow channel communicating between the annular flow channel and the suction port. The piston pump according to any one of claims 1 to 5, wherein the discharge port communicates with the motor housing via the discharge side valve, and is attached to the motor housing side of the housing. A piston pump communicating with a discharge port formed in an outlet cover and opening to the outside of the housing, and fluid discharged from the discharge port flows through the housing and flows out of the housing from the discharge port. . 7. The piston pump according to claim 6, wherein the motor is immersed in a fluid discharged from the discharge port. The piston pump according to any one of claims 1 to 7, wherein the piston pump is a fuel supply pump for a motorcycle.

Images