Diaphragm pump

Abstract

To provide a diaphragm pump capable of reducing the number of components.SOLUTION: A diaphragm pump 1 is operated by receiving pulsation pressure in a crank chamber 2a. The diaphragm pump 1 includes: a high pressure-side diaphragm 20 having a high pressure-side operation portion 20a operated by the pulsation pressure to suck and discharge a fuel; and a supply valve 50 disposed in a supply passage L12 for supplying the fuel to a pump chamber R21 to permit circulation of the fuel in a direction toward the pump chamber R21. The supply valve 50 has a supply-side valve element 51 for opening and closing a supply-side inflow port H11 disposed on a supply-side fuel chamber F1. The supply-side valve element 51 is composed of a part excluding the high pressure-side operation portion 20a, of the high pressure-side diaphragm 20.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a diaphragm pump that operates by receiving pulsating pressure in a crankcase of an engine. [Background technology]

[0002] For example, an engine unit mounted on a work machine such as a brush cutter is equipped with a fuel pump that supplies fuel from a fuel tank to a fuel injection device. For example, a diaphragm pump is sometimes used as the fuel pump to supply fuel without using electricity. This diaphragm pump operates by receiving pulsating pressure in the crank chamber of the engine. Such a diaphragm pump is described, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-90846 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned diaphragm pump requires a diaphragm that operates under pulsating pressure, a plurality of valves, and other components. For this reason, there is a demand in this technical field for a diaphragm pump that can reduce the number of components. [Means for solving the problem]

[0005] The present invention relates to a diaphragm pump (1) that is operated by receiving pulsating pressure in a crank chamber (2a) of an engine (2), the diaphragm pump (1) comprising: a diaphragm (20) that is operated by the pulsating pressure and has a diaphragm operating portion (20a) that draws fuel into a discharge chamber (R21) and discharges the fuel in the discharge chamber; a supply valve (50) that is provided in a supply passage (L12) that supplies the fuel to the discharge chamber (R21) and allows the fuel to flow only in a direction toward the discharge chamber (R21); and a discharge valve (60) that is provided in a discharge passage (L13) that discharges the fuel from the discharge chamber (R21) and allows the fuel to flow only in a direction discharged from the discharge chamber (R21). A fuel chamber (F1) is provided in a middle portion of the supply passage (L12), and the fuel chamber (F1) contains a fuel chamber (F2) that receives the fuel. a supply passage (L12a) that is a portion of the supply passage (L12) upstream of the fuel chamber (F1) and an outlet (H12) that allows the fuel to flow out from the fuel chamber (F1) are disposed in the fuel chamber (F1), and the supply valve (50) has a valve body (51) that is disposed in the fuel chamber (F1) and covers the inlet (H11) in an openable and closable manner, and a biasing member (52) that biases the valve body (51) so that the inlet (H11) is closed, and the valve body (51) is constituted by a portion of the diaphragm (20) other than the diaphragm operating portion (20a).

[0006] In this diaphragm pump (1), the valve element (51) of the supply valve (50) is formed by a part of the diaphragm (20). In other words, the diaphragm (20) has a diaphragm operating portion (20a) and a valve element (51). Therefore, the diaphragm pump (1) does not need to have the valve element (51) as a part separate from the diaphragm (20). In this way, the number of parts in the diaphragm pump (1) can be reduced.

[0007] The present invention relates to a diaphragm pump (1) that operates by receiving pulsating pressure in a crank chamber (2a) of an engine (2), comprising: a diaphragm (20) that operates by the pulsating pressure and has a diaphragm operating portion (20a) that draws fuel into a discharge chamber (R21) and discharges the fuel in the discharge chamber; a supply valve (50) that is provided in a supply passage (L12) that supplies the fuel to the discharge chamber (R21) and allows the fuel to flow only in a direction toward the discharge chamber (R21); and a discharge valve (60) that is provided in a discharge passage (L13) that discharges the fuel from the discharge chamber (R21) and allows the fuel to flow only in a direction discharged from the discharge chamber (R21). A fuel chamber (F2) is provided in a middle portion of the discharge passage (L13), and the fuel chamber (F2) contains a fuel chamber (F2) that receives the fuel. a flow inlet (H21) for allowing the fuel to flow into the fuel chamber (F2) from an upstream discharge passage (L13a), which is a portion of the discharge passage (L13) upstream of the fuel chamber (F2), and a flow outlet (H22) for allowing the fuel to flow out from the fuel chamber (F2), which faces a downstream discharge passage (L13b), which is a portion of the discharge passage (L13) downstream of the fuel chamber (F2), the discharge valve (60) has a valve body (61) that is disposed in the fuel chamber (F2) and covers the flow inlet (H21) in an openable and closable manner, and a biasing member (62) that biases the valve body (61) so as to close the flow inlet (H21), and the valve body (61) is constituted by a portion of the diaphragm (20) other than the diaphragm operating portion (20a).

[0008] In this diaphragm pump (1), the valve element (61) of the discharge valve (60) is formed by a part of the diaphragm (20). In other words, the diaphragm (20) has a diaphragm operating portion (20a) and a valve element (61). Therefore, the diaphragm pump (1) does not need to include the valve element (61) as a part separate from the diaphragm (20). In this way, the number of parts in the diaphragm pump (1) can be reduced.

[0009] The present invention may be the diaphragm pump (1) according to the above [1] or [2], [3] "wherein the diaphragm (20) is provided with a pair of slits (K11 and K12, and K21 and K22) in the fuel chamber (F1, F2) so as to sandwich the inlet (H11, H21), and the valve body (51, 61) is configured by a portion of the diaphragm (20) between the pair of slits (K11 and K12, and K21 and K22)." In this case, both ends of the valve body (51, 61) in the extending direction of the slits (K11 and K12, and K21 and K22) are connected to a portion of the diaphragm (20) other than the diaphragm operating portion (20a). Therefore, the valve body (51, 61) is suppressed from being turned up when the inlet (H11, H21) is opened or closed. In this manner, the valve (51, 61) can appropriately open and close the inflow ports (H11, H21).

[0010] The present invention may be [4] "the diaphragm pump (1) according to the above [3], wherein the extension direction of the slits (K11 and K12, and K21 and K22) is along the fuel flow direction from the inlet (H11, H21) to the outlet (H12, H22) in the fuel chamber (F1, F2)." In this case, both ends of the valve body (51, 61) along the fuel flow direction are connected to a portion of the diaphragm (20) other than the diaphragm operating portion (20a). This prevents the valve body (51, 61) from being turned up due to the flow of fuel in the fuel chamber (F1, F2).

[0011] The present invention may be [5] "the diaphragm pump (1) according to any one of the above [1] to [4], wherein the fuel chamber (F1, F2) has a width that narrows around the outlet (H12, H22) toward the outlet (H12, H22)." In this case, the diaphragm pump (1) can guide the fuel moving from the inlet (H11, H21) toward the outlet (H12, H22) in the fuel chamber (F1, F2), toward the outlet (H12, H22). In this way, the diaphragm pump (1) can suppress the accumulation of fuel in the fuel chamber (F1, F2).

[0012] The present invention may be [6] "the diaphragm pump (1) according to any one of the above [1] to [5], wherein an outer diameter of the urging member (52, 62) is larger than a diameter of the inlet (H11, H21)." In this case, the urging member (52, 62) can appropriately urge the valve body (51, 61) so as to cover the inlet (H11, H21) without the valve body (51, 61) getting into the inlet (H11, H21). Effect of the Invention

[0013] According to the present invention, the number of parts can be reduced. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram showing an engine unit provided with a diaphragm pump according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a diaphragm pump. [Diagram 3] Figure 3(a) is an enlarged cross-sectional view of the supply valve and its surroundings when the valve is closed, and Figure 3(b) is an enlarged cross-sectional view of the supply valve and its surroundings when the valve is open. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5]Fig. 5(a) is an enlarged cross-sectional view of the discharge valve and its surroundings when the valve is closed, and Fig. 5(b) is an enlarged cross-sectional view of the discharge valve and its surroundings when the valve is open. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0016] As shown in Fig. 1, a diaphragm pump 1 according to this embodiment functions as a fuel pump that supplies fuel to an engine 2. The diaphragm pump 1 operates upon receiving pulsating pressure (pressure fluctuations of gas in the crank chamber 2a) in a crank chamber 2a of the engine 2. Here, the diaphragm pump 1 is connected to the crank chamber 2a of the engine 2 by a pipe L3. This allows the diaphragm pump 1 to receive the pulsating pressure of the crank chamber 2a via the pipe L3.

[0017] The diaphragm pump 1 draws fuel from the fuel tank 3 via a pipe L2, and supplies the pressurized fuel via a pipe L1 to a fuel injection device 2b provided in the engine 2. The diaphragm pump 1 may also have a mechanism for returning surplus fuel drawn from the fuel tank 3 that is not supplied to the engine 2, back to the tank.

[0018] More specifically, the diaphragm pump 1 includes a low-pressure side diaphragm 10, a high-pressure side diaphragm (diaphragm) 20, a connecting portion 30, a main body portion 40, a supply valve 50, and a discharge valve 60, as shown in FIG.

[0019] The main body 40 has a first operating region R10 and a second operating region R20 therein, which will be described later. In this embodiment, the main body 40 is configured by stacking a first main body 41, a second main body 42, a third main body 43, and a fourth main body 44 in this order. Gaskets are appropriately disposed between the stacked members such as the first main body 41 to the fourth main body 44. The first main body 41 to the fourth main body 44 are fixed to each other by screws or the like (not shown).

[0020] A first operating region R10 is formed between the first body portion 41 and the second body portion 42. The first operating region R10 is a region in which the low-pressure-side operating portion 10a of the low-pressure-side diaphragm 10 operates. The first operating region R10 has an approximate shape of a thin cylinder whose axis is the stacking direction of the first body portion 41 and the second body portion 42.

[0021] Here, a recess 41a is provided on the surface of the first body portion 41 facing the second body portion 42. Also, a recess 42a is provided on the surface of the second body portion 42 facing the first body portion 41. The recess 41a and the recess 42a face each other. The first operating region R10 is formed by the recess 41a of the first body portion 41 and the recess 42a of the second body portion 42.

[0022] A pulsation transmission port S1 is formed in the first main body portion 41. A pipe L3 (see FIG. 1) leading to the crank chamber 2a of the engine 2 is connected to the pulsation transmission port S1. Also, a pulsation transmission path L11 is formed in the first main body portion 41, connecting the pulsation transmission port S1 and the first operating region R10.

[0023] A second operating region R20 is formed between the second body portion 42 and the third body portion 43. The second operating region R20 is a region in which the high-pressure-side operating portion 20a of the high-pressure-side diaphragm 20 operates. The second operating region R20 has an approximate shape of a thin cylinder whose axis is the stacking direction of the second body portion 42 and the third body portion 43.

[0024] Here, a recess 42b is provided on the surface of the second body portion 42 facing the third body portion 43. A recess 43a is provided on the surface of the third body portion 43 facing the second body portion 42. The recess 42b and the recess 43a face each other. The second operating region R20 is formed by the recess 42b of the second body portion 42 and the recess 43a of the third body portion 43.

[0025] An intake port S2 and an exhaust port S3 are formed in the fourth main body portion 44. A pipe L2 (see FIG. 1) leading to the fuel tank 3 is connected to the intake port S2. A pipe L1 leading to the fuel injection device 2b of the engine 2 is connected to the exhaust port S3.

[0026] Between the first body portion 41 and the second body portion 42, an elastically deformable low-pressure side diaphragm 10 is disposed. That is, the low-pressure side diaphragm 10 divides the first operating region R10 into two. The low-pressure side diaphragm 10 is held by the first body portion 41 and the second body portion 42 by being sandwiched between them. As a result, the space between the low-pressure side diaphragm 10 and the recessed portion 41a of the first body portion 41 in the first operating region R10 communicates with the crank chamber 2a via the pulsation transmission path L11 and the piping L3. Hereinafter, the space between the low-pressure side diaphragm 10 and the recessed portion 41a of the first body portion 41 in the first operating region R10 is referred to as the pulsation operating chamber R11. The pulsation pressure of the crank chamber 2a is transmitted to the pulsation operating chamber R11 via the pulsation transmission path L11 and the piping L3.

[0027] Of the low-pressure side diaphragm 10, the portion within the first operating region R10 is the operating range in which it operates when it receives the pulsating pressure in the crank chamber 2a. Hereinafter, the portion of the low-pressure side diaphragm 10 within the first operating region R10 will be referred to as low-pressure side operating portion 10a.

[0028] A low-pressure side backup 11 is attached to the low-pressure side operating portion 10a of the low-pressure side diaphragm 10. In this embodiment, two low-pressure side backups 11 are provided. The two low-pressure side backups 11 sandwich the low-pressure side operating portion 10a.

[0029] In this manner, the low-pressure side diaphragm 10 faces the pulsation operating chamber R11. That is, the low-pressure side diaphragm 10 forms a part of the pulsation operating chamber R11 to which the pulsation pressure of the crank chamber 2a of the engine 2 is transmitted. Therefore, the low-pressure side operating portion 10a of the low-pressure side diaphragm 10 operates by receiving the pulsation pressure of the crank chamber 2a.

[0030] An elastically deformable high-pressure side diaphragm 20 is disposed between the second body portion 42 and the third body portion 43. The high-pressure side diaphragm 20 is held by the second body portion 42 and the third body portion 43 by being sandwiched between the second body portion 42 and the third body portion 43. The high-pressure side diaphragm 20 also extends to a portion other than the second operating region R20 between the second body portion 42 and the third body portion 43. Specifically, the high-pressure side diaphragm 20 also extends to a portion of a supply side fuel chamber F1 and a discharge side fuel chamber F2, which will be described later. In this embodiment, the high-pressure side diaphragm 20 has a shape that extends over the entire contact surface between the second body portion 42 and the third body portion 43.

[0031] The high-pressure side diaphragm 20 divides the second operating region R20 into two. Hereinafter, the space between the high-pressure side diaphragm 20 and the recess 43a of the third main body portion 43 is referred to as the pump chamber (discharge chamber) R21. The portion of the high-pressure side diaphragm 20 within the second operating region R20 is the operating range that operates in response to the pulsating pressure in the crank chamber 2a. Hereinafter, the portion of the high-pressure side diaphragm 20 within the second operating region R20 is referred to as the high-pressure side operating portion (diaphragm operating portion) 20a.

[0032] A high-pressure side backup 21 is attached to the high-pressure side operating portion 20a of the high-pressure side diaphragm 20. In this embodiment, two high-pressure side backups 21 are provided. The two high-pressure side backups 21 sandwich the high-pressure side operating portion 20a.

[0033] In this manner, the high-pressure side operating portion 20a of the high-pressure side diaphragm 20 faces the pump chamber R21. As described below, the pump chamber R21 generates pressurized fuel to be supplied to the fuel injection device 2b of the engine 2. That is, the high-pressure side operating portion 20a of the high-pressure side diaphragm 20 forms a part of the pump chamber R21 that supplies fuel to the fuel injection device 2b of the engine 2. The high-pressure side operating portion 20a operates in conjunction with the low-pressure side diaphragm 10. As a result, the high-pressure side operating portion 20a draws fuel from the fuel tank 3 into the pump chamber R21, and supplies (discharges) the fuel in the pump chamber R21 toward the fuel injection device 2b.

[0034] The connecting portion 30 is passed through a guide hole 42c provided in the second main body portion 42, and connects the low-pressure side diaphragm 10 and the high-pressure side diaphragm 20. The connecting portion 30 includes, for example, a sleeve 31 and a rivet 32. The sleeve 31 is disposed between the low-pressure side diaphragm 10 and the high-pressure side diaphragm 20. The rivet 32 ​​fixes the low-pressure side diaphragm 10 and the high-pressure side diaphragm 20 to the sleeve 31 with the sleeve 31 sandwiched between the low-pressure side diaphragm 10 and the high-pressure side diaphragm 20. This allows the high-pressure side operating portion 20a to operate in conjunction with the low-pressure side operating portion 10a. In other words, the high-pressure side operating portion 20a operates in conjunction with the low-pressure side operating portion 10a, which operates by the pulsating pressure of the crank chamber 2a of the engine 2, by being connected by the connecting portion 30.

[0035] A supply passage L12 that connects the suction port S2 and the pump chamber R21 is formed in the main body 40. That is, the supply passage L12 supplies the fuel guided from the fuel tank 3 to the suction port S2 via the pipe L2 to the pump chamber R21. In this embodiment, the supply passage L12 is formed by grooves and holes provided in the second main body 42, the third main body 43, and the fourth main body 44.

[0036] A supply-side fuel chamber (fuel chamber) F1 is provided in the middle of the supply passage L12. In this embodiment, the supply-side fuel chamber F1 is formed, for example, by a recess 42d provided on a surface of the second body portion 42 facing the third body portion 43, and the third body portion 43. A supply-side inlet (inlet) H11 and a supply-side outlet (outlet) H12 face the supply-side fuel chamber F1 (see FIG. 3(b)).

[0037] Here, the portion of the supply passage L12 upstream of the supply-side fuel chamber F1 is referred to as the upstream supply passage L12a. The portion of the supply passage L12 downstream of the supply-side fuel chamber F1 is referred to as the downstream supply passage L12b. The supply-side inlet H11 is an inlet that allows fuel to flow from the upstream supply passage L12a into the supply-side fuel chamber F1. The supply-side outlet H12 is an outlet that allows fuel to flow from the supply-side fuel chamber F1 to the downstream supply passage L12b.

[0038] A discharge passage L13 that connects the pump chamber R21 and the discharge port S3 is formed in the main body 40. That is, the discharge passage L13 guides the fuel pressurized in the pump chamber R21 to the discharge port S3. In this embodiment, the discharge passage L13 is formed by grooves and holes provided in the second main body 42, the third main body 43, and the fourth main body 44.

[0039] A discharge-side fuel chamber (fuel chamber) F2 is provided in the middle of the discharge passage L13. In this embodiment, the discharge-side fuel chamber F2 is formed, for example, by a recess 42e provided on a surface of the second body portion 42 facing the third body portion 43, and the third body portion 43. A discharge-side inlet (inlet port) H21 and a discharge-side outlet (outlet port) H22 face the discharge-side fuel chamber F2 (see FIG. 5(b)).

[0040] Here, the portion of the discharge passage L13 upstream of the discharge side fuel chamber F2 is referred to as the upstream discharge passage L13a. The portion of the discharge passage L13 downstream of the discharge side fuel chamber F2 is referred to as the downstream discharge passage L13b. The discharge side inlet H21 is an inlet that allows fuel to flow from the upstream discharge passage L13a into the discharge side fuel chamber F2. The discharge side outlet H22 is an outlet that allows fuel to flow from the discharge side fuel chamber F2 to the downstream discharge passage L13b.

[0041] The supply valve 50 is provided in the supply passage L12. The supply valve 50 only allows fuel to flow in a direction toward the pump chamber R21. The discharge valve 60 is provided in the discharge passage L13. The discharge valve 60 only allows fuel to flow in a direction discharged from the pump chamber R21. When the high-pressure side operating unit 20a operates, the supply valve 50 and the discharge valve 60 open and close to send fuel from the supply passage L12 to the pump chamber R21 and discharge the fuel from the pump chamber R21 via the discharge passage L13. In other words, the supply valve 50 and the discharge valve 60 open and close to realize a pump mechanism by the operation of the high-pressure side operating unit 20a.

[0042] As shown in FIGS. 3(a) and 3(b), the supply valve 50 includes a supply-side valve body (valve body) 51 and a supply-side spring (biasing member) 52. The supply-side valve body 51 is disposed in the supply-side fuel chamber F1. The supply-side valve body 51 covers the supply-side inlet H11 facing the supply-side fuel chamber F1 in an openable and closable manner. The supply-side spring 52 biases the supply-side valve body 51 so as to close the supply-side inlet H11. By opening and closing the supply-side valve body 51, the supply valve 50 allows the flow of fuel in the supply path L12 only in the direction from the suction port S2 to the pump chamber R21, and blocks the flow of fuel in the opposite direction.

[0043] Here, when the high-pressure side actuating unit 20a performs a suction operation, the supply-side valve body 51 moves to compress the supply-side spring 52 as shown in FIG. 3(b). This suction operation is an operation of the high-pressure side actuating unit 20a to increase the volume of the pump chamber R21. In other words, the suction operation of the high-pressure side actuating unit 20a creates a negative pressure in the downstream supply passage L12b and the pump chamber R21. As a result, the supply-side valve body 51 bends against the biasing force of the supply-side spring 52 and moves away from the supply-side inlet H11. The movement of the supply-side valve body 51 opens the supply-side inlet H11, and fuel is sucked from the suction port S2 toward the pump chamber R21.

[0044] When the high-pressure side actuation unit 20a performs a discharge operation, the supply-side valve body 51 is pressed against the supply-side inlet H11 side as shown in Fig. 3(a). This discharge operation is an operation of the high-pressure side actuation unit 20a to reduce the volume of the pump chamber R21. That is, the fuel pressurized in the pump chamber R21 urges the supply-side valve body 51 toward the supply-side inlet H11 side via the downstream supply passage L12b, and the supply-side spring 52 urges the supply-side valve body 51 toward the supply-side inlet H11 side. As a result, when a discharge operation is performed, fuel does not flow from the upstream supply passage L12a into the supply-side fuel chamber F1.

[0045] As shown in Fig. 4, in the supply-side fuel chamber F1, the high-pressure-side diaphragm 20 is provided with a pair of suction-side slits (slits) K11 and K12, sandwiching the supply-side inlet H11. The supply-side inlet H11 is located between the suction-side slits K11 and K12. The supply-side valve body 51 is formed by the high-pressure-side diaphragm 20. Specifically, in this embodiment, the supply-side valve body 51 is formed by a portion of the high-pressure-side diaphragm 20 between the pair of suction-side slits K11 and K12. In other words, the supply-side valve body 51 is formed by a portion of the high-pressure-side diaphragm 20 other than the high-pressure-side operating portion 20a.

[0046] An outflow hole 20b is provided in a portion of the high-pressure side diaphragm 20 facing the supply side outlet H12. The extension direction of the suction side slits K11 and K12 is aligned with the fuel flow direction from the supply side inlet H11 to the supply side outlet H12 in the supply side fuel chamber F1.

[0047] 3(b) and 4, the high-pressure side operating part 20a performs a suction operation, whereby the supply-side valve body 51 moves and the supply-side inlet H11 opens. As a result, the fuel that has flowed into the supply-side fuel chamber F1 through the supply-side inlet H11 flows through the suction-side slits K11 and K12 toward the second main body portion 42 side relative to the supply-side valve body 51 (high-pressure side diaphragm 20). Then, the fuel that has flowed into the supply-side fuel chamber F1 toward the second main body portion 42 side relative to the high-pressure side diaphragm 20 flows out through the outlet hole 20b of the high-pressure side diaphragm 20 and the supply-side outlet H12 to the downstream discharge passage L13b.

[0048] In this embodiment, the width of the supply-side fuel chamber F1 is narrowed around the supply-side outlet H12 toward the supply-side outlet H12. The supply-side spring 52 is an annular coil spring. The outer diameter of the supply-side spring 52 is larger than the diameter of the supply-side inlet H11.

[0049] As shown in Figures 5(a) and 5(b), the discharge valve 60 includes a discharge side valve body (valve body) 61 and a discharge side spring (biasing member) 62. The discharge side valve body 61 is disposed in the discharge side fuel chamber F2. The discharge side valve body 61 covers the discharge side inlet H21 facing the discharge side fuel chamber F2 in an openable and closable manner. The discharge side spring 62 biases the discharge side valve body 61 so as to close the discharge side inlet H21. By opening and closing the discharge side valve body 61, the discharge valve 60 allows the flow of fuel in the discharge passage L13 only in the direction from the pump chamber R21 to the discharge port S3, and blocks the flow of fuel in the opposite direction.

[0050] Here, when the high-pressure side operating part 20a performs a discharge operation, the discharge side valve body 61 moves so as to compress the discharge side spring 62 as shown in FIG. 5(b). That is, the fuel pressurized in the pump chamber R21 urges the discharge side valve body 61 through the upstream discharge passage L13a. When the force of the fuel urging the discharge side valve body 61 becomes greater than the urging force of the discharge side spring 62, the discharge side valve body 61 bends and moves so as to move away from the discharge side inlet H21. The movement of the discharge side valve body 61 opens the discharge side inlet H21, and fuel is discharged from the pump chamber R21 toward the discharge port S3. The urging force of the discharge side spring 62 is set so that the discharge side valve body 61 does not move away from the discharge side inlet H21 until the fuel in the pump chamber R21 reaches a predetermined pressure. That is, the diaphragm pump 1 can discharge fuel at a predetermined pressure.

[0051] When the high-pressure side actuating unit 20a performs a suction operation, the discharge side valve body 61 is pressed against the discharge side inlet H21 as shown in Fig. 5(a). That is, the suction operation of the high-pressure side actuating unit 20a creates a negative pressure in the upstream discharge passage L13ab and the pump chamber R21. As a result, the discharge side valve body 61 is biased toward the discharge side inlet H21 by the negative pressure, and is also biased toward the discharge side inlet H21 by the discharge side spring 62. In this way, when a discharge operation is performed, fuel does not flow from the upstream discharge passage L13a into the discharge side fuel chamber F2.

[0052] As shown in FIG. 6, the high-pressure side diaphragm 20 is provided with a pair of discharge side slits (slit) K21 and discharge side (slit) slit K22 in the discharge side fuel chamber F2, sandwiching the discharge side inlet H21. The discharge side inlet H21 is located between the discharge side slit K21 and the discharge side slit K22. The discharge side valve body 61 is formed by the high-pressure side diaphragm 20. Specifically, in this embodiment, the discharge side valve body 61 is formed by a portion of the high-pressure side diaphragm 20 between the pair of discharge side slits K21 and K22. That is, the discharge side valve body 61 is formed by a portion of the high-pressure side diaphragm 20 other than the high-pressure side operating portion 20a. In this way, the high-pressure side diaphragm 20 has the high-pressure side operating portion 20a, the supply side valve body 51, and the supply side spring 52.

[0053] An outflow hole 20c is provided in a portion of the high-pressure side diaphragm 20 facing the discharge side outlet H22. The extending direction of the discharge side slits K21 and K22 is aligned with the fuel flow direction from the discharge side inlet H21 to the discharge side outlet H22 in the discharge side fuel chamber F2.

[0054] As shown in Fig. 5(b) and Fig. 6, the high pressure side operating part 20a performs a discharge operation, whereby the discharge side valve body 61 moves and the discharge side inlet H21 opens. As a result, the fuel that has flowed into the discharge side fuel chamber F2 through the discharge side inlet H21 flows through the discharge side slits K21 and K22 toward the second main body portion 42 side from the discharge side valve body 61 (high pressure side diaphragm 20). Then, the fuel that has flowed into the discharge side fuel chamber F2 toward the second main body portion 42 side from the high pressure side diaphragm 20 flows out to the downstream discharge passage L13b through the outlet hole 20c of the high pressure side diaphragm 20 and the discharge side outlet H22.

[0055] In this embodiment, the width of the discharge-side fuel chamber F2 is narrowed around the discharge-side outlet H22 toward the discharge-side outlet H22. The discharge-side spring 62 is an annular coil spring. The outer diameter of the discharge-side spring 62 is larger than the diameter of the discharge-side inlet H21.

[0056] As described above, in this diaphragm pump 1, the supply side valve body 51 of the supply valve 50 is formed by a part of the high pressure side diaphragm 20. Also, in this diaphragm pump 1, the discharge side valve body 61 of the discharge valve 60 is formed by a part of the high pressure side diaphragm 20. In other words, the high pressure side diaphragm 20 has the high pressure side operating portion 20a, the supply side valve body 51, and the discharge side spring 62. Therefore, the diaphragm pump 1 does not need to have the supply side valve body 51 and the discharge side valve body 61 as parts separate from the high pressure side diaphragm 20. In this way, in this diaphragm pump 1, the number of parts can be reduced.

[0057] The supply-side valve body 51 of the supply valve 50 is biased by a supply-side spring 52. The discharge-side valve body 61 of the discharge valve 60 is biased by a discharge-side spring 62. As a result, even if the pulsating pressure in the crank chamber 2a changes at high speed, the supply-side valve body 51 and the discharge-side valve body 61 can open and close in response to the change in the pulsating pressure.

[0058] The supply side valve body 51 of the supply valve 50 is formed by a portion between the suction side slits K11 and K12 in the high pressure side diaphragm 20. In this case, both ends of the supply side valve body 51 in the extension direction of the suction side slits K11 and K12 are connected to the high pressure side diaphragm 20 other than the high pressure side operating portion 20a and the discharge side valve body 61. Therefore, the supply side valve body 51 is prevented from being turned up when the supply side inlet H11 is opened or closed. In this way, the supply side valve body 51 can appropriately open and close the supply side inlet H11.

[0059] Similarly, the discharge side valve body 61 of the discharge valve 60 is formed by a portion between the discharge side slits K21 and K22 in the high pressure side diaphragm 20. In this case, both ends of the discharge side valve body 61 in the extending direction of the discharge side slits K21 and K22 are connected to the portion of the high pressure side diaphragm 20 other than the high pressure side operating portion 20a and the supply side valve body 51. Therefore, the discharge side valve body 61 is prevented from being turned up when the discharge side inlet H21 is opened and closed. In this way, the discharge side valve body 61 can appropriately open and close the discharge side inlet H21.

[0060] The extension direction of the suction side slits K11 and K12 forming the supply side valve body 51 of the supply valve 50 is along the fuel flow direction from the supply side inlet H11 to the supply side outlet H12 in the supply side fuel chamber F1. In this case, the supply side valve body 51 is in a state where both ends along the fuel flow direction are connected to the high pressure side diaphragm 20 other than the high pressure side operating part 20a and the discharge side valve body 61. In other words, the supply side valve body 51 does not extend so as to cross the fuel flow. The supply side valve body 51 extends along the fuel flow direction. Therefore, the supply side valve body 51 is prevented from being turned up due to the fuel flow in the supply side fuel chamber F1.

[0061] Similarly, the extension direction of the discharge side slits K21 and K22 forming the discharge side valve body 61 of the discharge valve 60 is along the fuel flow direction from the discharge side inlet H21 to the discharge side outlet H22 in the discharge side fuel chamber F2. In this case, the discharge side valve body 61 is in a state where both ends along the fuel flow direction are connected to the high pressure side diaphragm 20 other than the high pressure side operating part 20a and the supply side valve body 51. In other words, the discharge side valve body 61 does not extend so as to cross the fuel flow. The discharge side valve body 61 extends along the fuel flow direction. Therefore, the discharge side valve body 61 is prevented from being turned up due to the fuel flow in the discharge side fuel chamber F2.

[0062] The width of the supply-side fuel chamber F1 narrows around the supply-side outlet H12 toward the supply-side outlet H12. In this case, the diaphragm pump 1 can guide the fuel from the supply-side inlet H11 toward the supply-side outlet H12 in the supply-side fuel chamber F1 toward the supply-side outlet H12 as shown by the arrow Y1 in FIG. 4. Similarly, the width of the discharge-side fuel chamber F2 narrows around the discharge-side outlet H22 toward the discharge-side outlet H22. In this case, the diaphragm pump 1 can guide the fuel from the discharge-side inlet H21 toward the discharge-side outlet H22 in the discharge-side fuel chamber F2 toward the discharge-side outlet H22 as shown by the arrow Y2 in FIG. In this way, the diaphragm pump 1 can suppress the stagnation of fuel in the supply-side fuel chamber F1 and the discharge-side fuel chamber F2.

[0063] In the supply valve 50, the outer diameter of the supply-side spring 52 is larger than the diameter of the supply-side inlet H11. In this case, the supply-side spring 52 can appropriately urge the supply-side valve body 51 to cover the supply-side inlet H11 without the supply-side valve body 51 entering the supply-side inlet H11. Similarly, in the discharge valve 60, the outer diameter of the discharge-side spring 62 is larger than the diameter of the discharge-side inlet H21. In this case, the discharge-side spring 62 can appropriately urge the discharge-side valve body 61 to cover the discharge-side inlet H21 without the supply-side valve body 61 entering the discharge-side inlet H21.

[0064] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the shape of the pulsation transmission path L11, the shape of the supply path L12, and the shape of the discharge path L13 provided in the main body 40 are not limited to the configuration shown in Fig. 2. Furthermore, the configurations of the low-pressure side operating part 10a and the high-pressure side operating part 20a are not limited to the above configuration.

[0065] In the above embodiment, the supply side valve body 51 and the discharge side valve body 61 are configured by a part of the high pressure side diaphragm 20. However, this is not limited to this, and either the supply side valve body 51 or the discharge side valve body 61 may be configured by a part of the high pressure side diaphragm 20. Furthermore, the supply side valve body 51 and the discharge side valve body 61 are not limited to being configured by a part of the high pressure side diaphragm 20. At least one of the supply side valve body 51 and the discharge side valve body 61 may be configured by a part of the low pressure side diaphragm (diaphragm) 10.

[0066] The diaphragm pump 1 is not limited to having two diaphragms, the low-pressure side diaphragm 10 and the high-pressure side diaphragm 20. The diaphragm pump 1 may be configured to have only one diaphragm. In this case, it is sufficient that at least one of the supply side valve body 51 and the discharge side valve body 61 is configured by a part of the diaphragm provided in the diaphragm pump 1. [Explanation of symbols]

[0067] 1...diaphragm pump, 2...engine, 2a...crank chamber, 20...high pressure side diaphragm (diaphragm), 20a...high pressure side operating part (diaphragm operating part), 50...supply valve, 51...supply side valve body (valve body), 52...supply side spring (biasing member), 60...discharge valve, 61...discharge side valve body (valve body), 62...discharge side spring (biasing member), F1...supply side fuel chamber (fuel chamber), F2...discharge side fuel chamber (fuel chamber), H11...supply side inlet (inlet), H12...supply Supply side outlet (outlet), H21...discharge side inlet (inlet), H22...discharge side outlet (outlet), K11...suction side slit (slit), K12...suction side slit (slit), K21...discharge side slit (slit), K22...discharge side slit (slit), L12...supply path, L12a...upstream supply path, L12b...downstream supply path, L13...discharge path, L13a...upstream discharge path, L13b...downstream discharge path, R21...pump chamber (discharge chamber).

Claims

1. A diaphragm pump (1) that operates by receiving pulsating pressure in a crank chamber (2a) of an engine (2), a diaphragm (20) having a diaphragm operating portion (20a) that is actuated by the pulsating pressure to draw fuel into a discharge chamber (R21) and discharge the fuel in the discharge chamber; a supply valve (50) provided in a supply passage (L12) that supplies the fuel to the discharge chamber (R21), the supply valve (50) allowing the fuel to flow only in a direction toward the discharge chamber (R21); a discharge valve (60) provided in a discharge passage (L13) that discharges the fuel from the discharge chamber (R21), and that allows the fuel to flow only in a direction in which the fuel is discharged from the discharge chamber (R21); Equipped with A fuel chamber (F1) is provided in the middle of the supply path (L12), The fuel chamber (F1) includes: an inlet (H11) for allowing the fuel to flow into the fuel chamber (F1) from an upstream supply passage (L12a) which is a portion of the supply passage (L12) upstream of the fuel chamber (F1); a downstream supply passage (L12b) which is a portion of the supply passage (L12) downstream of the fuel chamber (F1), and an outlet (H12) for allowing the fuel to flow out from the fuel chamber (F1); is coming, The supply valve (50) a valve body (51) disposed in the fuel chamber (F1) and covering the inlet (H11) in an openable and closable manner; a biasing member (52) that biases the valve body (51) so as to close the inlet (H11); having The diaphragm pump (1), wherein the valve body (51) is formed by a portion of the diaphragm (20) other than the diaphragm operating portion (20a).

2. A diaphragm pump (1) that operates by receiving pulsating pressure in a crank chamber (2a) of an engine (2), a diaphragm (20) having a diaphragm operating portion (20a) that is actuated by the pulsating pressure to draw fuel into a discharge chamber (R21) and discharge the fuel in the discharge chamber; a supply valve (50) provided in a supply passage (L12) that supplies the fuel to the discharge chamber (R21), the supply valve (50) allowing the fuel to flow only in a direction toward the discharge chamber (R21); a discharge valve (60) provided in a discharge passage (L13) that discharges the fuel from the discharge chamber (R21), and that allows the fuel to flow only in a direction in which the fuel is discharged from the discharge chamber (R21); Equipped with A fuel chamber (F2) is provided in the middle of the discharge passage (L13), The fuel chamber (F2) includes: an inlet (H21) for allowing the fuel to flow into the fuel chamber (F2) from an upstream discharge passage (L13a) which is a portion of the discharge passage (L13) upstream of the fuel chamber (F2); a downstream discharge passage (L13b) which is a portion of the discharge passage (L13) downstream of the fuel chamber (F2), the downstream discharge passage (L13b) has an outlet (H22) for allowing the fuel to flow out from the fuel chamber (F2); is coming, The discharge valve (60) a valve body (61) disposed in the fuel chamber (F2) and covering the inlet (H21) in an openable and closable manner; a biasing member (62) that biases the valve body (61) so as to close the inlet (H21); having The diaphragm pump (1), wherein the valve body (61) is formed by a portion of the diaphragm (20) other than the diaphragm operating portion (20a).

3. A pair of slits (K11 and K12, and K21 and K22) are provided in the diaphragm (20) in the fuel chamber (F1, F2) so as to sandwich the inlet (H11, H21), 3. The diaphragm pump (1) according to claim 1 or 2, wherein the valve body (51, 61) is formed by a portion of the diaphragm (20) between a pair of the slits (K11 and K12, and K21 and K22).

4. 4. The diaphragm pump (1) according to claim 3, wherein the extension direction of the slits (K11 and K12, and K21 and K22) is aligned along the flow direction of the fuel from the inlet (H11, H21) to the outlet (H12, H22) in the fuel chamber (F1, F2).

5. 3. The diaphragm pump (1) according to claim 1 or 2, wherein the fuel chamber (F1, F2) has a width that narrows around the outlet (H12, H22) toward the outlet (H12, H22).

6. The diaphragm pump (1) according to claim 1 or 2, wherein an outer diameter of the biasing member (52, 62) is larger than a diameter of the inlet (H11, H21).

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