JP6650387B2 - Reciprocating pump - Google Patents

Description

  The present invention relates to a reciprocating pump.

  As described in Patent Document 1, as a kind of a reciprocating pump, a disc-shaped stopper and a valve seat are fixed to a tip portion of a piston rod that reciprocates in a cylinder. For example, there is known a forced valve type piston pump including a water suction valve having a configuration in which a valve element is loosely fitted to a piston rod. The stopper is formed with a through hole penetrating in the axial direction (front and rear), and the fluid flows through the through hole. The stopper is fixed to the distal end side of the piston rod, and the valve seat is fixed to the proximal end side behind the stopper. The valve body has a piston packing which is in sliding contact with the inner circumferential surface of the cylinder on the outer circumferential side, and a packing fitting to which the piston packing is mounted is provided on the inner circumferential side. In the water absorption process in which the piston rod moves rearward (bottom dead center side) along the axis, the valve body abuts the stopper and the water absorption valve opens, forming the front end side of the cylinder and the front side of the piston rod. The pump chamber becomes a negative pressure and the liquid is absorbed by the pump chamber. In the discharge process in which the piston rod moves forward (top dead center side) along the axis, the valve body separates from the stopper, abuts the valve seat, closes the water absorption valve, and pressurizes the liquid in the pump chamber. The discharge valve facing the pump chamber opens.

  In the forced valve type piston pump described in Patent Literature 1, a crankcase, a cylinder base metal, the above-described cylinder, and a cylinder tip metal are provided as a drive unit case, and these are provided by a cylinder bolt screwed into the crankcase. Are connected and fixed. The cylinder is sandwiched between a cylinder base metal fitting and a cylinder tip metal fitting.

JP 2015-209833 A

  FIG. 5 is a longitudinal sectional view showing a main part of a conventional forced valve type piston pump. As shown in FIG. 5, the conventional forced valve type piston pump includes, for example, a cylinder base metal fitting 102 having a water suction port 101 formed therein, a cylinder tip metal fitting 104 having a discharge port 103 formed therein, and a cylinder base metal fitting 102. A cylinder 110 sandwiched between cylinder tip fittings 104; A water suction valve 107 having the same configuration as described above is provided at the tip end portion 106 a of the piston rod 106 disposed in the cylinder 110, and a discharge valve 108 is provided in the cylinder tip fitting 104. The rear end 110a of the cylinder 110 is inserted into a circular hole 102a formed on the distal end side of the cylinder base metal fitting 102, and is abutted against a step 102b. On the other hand, the front end portion 110b of the cylinder 110 is inserted into a circular hole portion 104a formed on the rear end side of the cylinder fitting 104, and abuts against the valve seat 109 of the discharge valve. The valve seat 109 is disposed in the hole 104a and mounted on the step 104b.

  In order to increase the water absorption in such a forced valve type piston pump, it is necessary to increase the volume of the space S in the cylinder 110. In order to increase the volume of the space S in the cylinder 110, it is conceivable to increase the inner diameter of the cylinder 110. As described above, since the front end 110b of the cylinder 110 is inserted into the cylinder fitting 104, when the inner diameter of the cylinder 110 is increased, it is necessary to newly manufacture the cylinder fitting 104. Alternatively, it is necessary to adopt a structure using a separate fitting for connecting the cylinder tip fitting 104 and the cylinder 110.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a reciprocating pump capable of increasing the amount of water absorption without increasing the number of parts while using a common cylinder tip fitting.

The reciprocating pump (P) according to one aspect of the present invention is formed on the front side in the axis (L) direction of the cylinder (3) by the reciprocating member (7) reciprocating in the cylindrical cylinder (3). A reciprocating pump (P) that performs a pumping action to pressurize / depressurize the pump chamber (13), and a cylinder tip fitting (4) disposed on the front side in the axis (L) direction of the cylinder (3); A discharge valve (15) arranged inside the tip fitting (4) to open and close the discharge flow path. The discharge valve (15) is attached to the rear end (4a) of the cylinder fitting (4) and supports a front end (3b) of the cylinder (3). 30) disposed on the front side in the direction of the axis (L) of the valve seat (30), and having a valve element (31) for opening and closing the discharge flow path by separating / contacting the front end (42a) of the valve seat (30). The valve seat (30) fits into the rear end (4a) of the cylinder tip fitting (4) and projects from the rear end (4a) rearward in the axial direction (L). 41) and a second tubular portion (42) formed on the tip side of the first tubular portion (41) and having an outer diameter smaller than that of the first tubular portion (41) and including a front end portion (42a). When, wherein the cylinder (3) the first cylindrical portion of the valve seat (30) to a front end portion (3b) is rear side of (41) is fitted in, by a valve seat (30) of the cylinder (3) The front end (3b) is supported, and the front side of the first tubular portion (41) and the second tubular portion (42) of the valve seat (30) are formed in the cylinder fitting (4). The first hole portion (4b) and the second hole portion (4d) having a smaller diameter than the first hole portion (4b) are fitted respectively to the first cylindrical portion (41) and the second hole portion (4d). An annular step (41c) formed between the ridges (42) is formed into an annular step (4c) formed between the first hole (4b) and the second hole (4d). In the direction of the axis (L) .

According to the reciprocating pump (P), the valve seat (30) attached to the rear end (4a) of the cylinder fitting (4) is actuated by the pumping action of increasing / decreasing the pressure in the pump chamber (13). As a result, the valve element (31) is separated / contacted, and the liquid is discharged through the discharge flow path. The first cylindrical portion (41) of the valve seat (30) projecting rearward from the rear end (4a) of the cylinder tip fitting (4) is fitted into the front end (3b) of the cylinder (3), The front end (3b) of the cylinder (3) is supported by the valve seat (30). As described above, the first tubular portion (41) of the valve seat (30) is projected from the cylinder fitting (4), and the cylinder (3) is arranged on the outer peripheral side of the first tubular portion (41). The diameter of the cylinder (3) can be increased without being restricted by the dimensions of the mounting portion formed on the cylinder tip fitting (4). Thereby, the volume of the internal space (S) of the cylinder (3) can be increased. As a result, the amount of water absorption in the reciprocating pump (P) can be increased. In this case, it is only necessary to change the valve seat (30) of the discharge valve (15), and it is not necessary to change the cylinder tip fitting (4). Therefore, the cylinder fitting (4) can be shared with the cylinder fitting originally used. Since it is not necessary to use a separate metal fitting for connecting the cylinder tip metal fitting (4) and the cylinder (3), an increase in the number of parts is suppressed.

In some aspects, the first tubular portion (41) of the valve seat (30) is disposed on the rear side in the axis (L) direction with respect to the rear end (4a) of the cylinder fitting (4), and A flange portion (43) facing the end surface (4e) of the rear end portion (4a); and a rear portion extending in the axial direction (L) beyond the flange portion (43) and extending to the front end portion (3b) of the cylinder (3). includes a side annular supporting portion and (44) which is after being fitted, the gap (G between the rear end portion of the cylinder target plate (4) end face of (4a) and (4e) and the flange portion (43) ) Is provided. At the time of maintenance or the like, the discharge valve (15) is inserted by inserting a tool into the gap (G) between the end surface (4e) of the rear end portion (4a) of the cylinder end fitting (4) and the flange portion (43). Can be easily removed. Thereby, maintainability is improved.

In some embodiments, the first tubular portion (41) of the valve seat (30) communicates with the internal space (S) of the cylinder (3) and forms at least a part of the pump chamber (13), A tapered liquid guide hole (46) having a diameter reduced toward the front side in the (L) direction is formed. Since the liquid guide hole (46) formed in the valve seat (30) is tapered, the change in shape is small, and the pipe resistance in the discharge process is reduced.

  According to some aspects of the present invention, it is possible to increase the amount of water absorption without increasing the number of parts while sharing the cylinder tip fitting (4).

It is a longitudinal section showing a reciprocating pump concerning an embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the principal part of the reciprocating pump of FIG. It is sectional drawing for demonstrating the dimension relationship of the valve seat of a discharge valve, and a cylinder tip metal fitting. FIG. 4A is an explanatory view of the operation of the main part in the water absorption step, and FIG. 4B is an explanatory view of the operation of the main part in the discharge step. It is a longitudinal cross-sectional view which expands and shows the principal part of the conventional forced valve type piston pump.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the forced valve type piston pump P includes a crankcase 1 as a drive unit case, a cylinder base metal fitting 2, a cylinder (cylinder pipe) 3, and a cylinder tip metal fitting 4. The crankcase 1, the cylinder base 2, the cylinder 3, and the cylinder end 4 arranged from left to right in the figure are connected in this order by connecting means such as cylinder bolts (not shown).

  Inside the crankcase 1, a crankshaft 5 and a connecting rod 6 as a driving unit are arranged. A piston rod 7 which is a reciprocating member is disposed inside the cylinder case 1 and the cylinder base 2 and the cylinder 3. The piston rod 7 is connected to the crankshaft 5 via a connecting rod 6, and reciprocates in the cylinder 3 in the left-right direction in the figure according to the rotation of the crankshaft 5. In the present embodiment, a plurality of connecting rods 6, piston rods 7, cylinders 3 and the like are arranged side by side in the direction perpendicular to the plane of the drawing. The forced valve type piston pump P is, for example, a triple pump. 1 shows a state in which the piston rod 7 moves forward by rotation of the crankshaft 5 and is located at the top dead center in a portion below the axis L, and a portion above the axis L The state where the piston rod 7 is retracted by rotation and located at the bottom dead center is shown.

  The crankcase 1 is filled with lubricating oil from an oil inlet 8. At a position where the piston rod 7 passes, an oil seal 9 is provided which is in sliding contact with the piston rod 7 to prevent the lubricating oil in the crankcase 1 from leaking to the cylinder base member 2 side. The lubricating oil in the crankcase 1 is made visible by an oil gauge 10 and can be discharged from a drain plug 11 as needed.

  The cylinder base metal fitting 2 is arranged on the rear side of the cylinder 3 in the axis L direction. A water suction port 16 for sucking a liquid is provided at an upper portion of the cylinder base 2. The cylinder base member 2 has a through hole that allows the piston rod 7 to reciprocate. A seal packing 12 is provided in the rear part of the cylinder base 2 to prevent the liquid on the cylinder base 2 from leaking to the oil seal 9 side when the piston rod 7 slides.

  In the cylinder 3, there is provided a water suction valve 14 that reciprocates in the direction of the axis L together with the piston rod 7. The water absorption valve 14 is attached to the tip 7c of the piston rod 7. The water intake valve 14 closes and opens a flow path to the pump chamber 13 formed on the distal end side of the cylinder 3 and simultaneously pressurizes / depressurizes the pump chamber 13 by a pump action.

  As shown in FIGS. 1 and 2, the water intake valve 14 includes a valve seat 20, a valve body 21 separated from / contact with the valve seat 20, a stopper 22, a collar 23, a washer 24, and a nut 25. The valve seat 20 is a disk provided with a through hole for passing the piston rod 7 at the center, and the collar 23 is a cylinder provided with a through hole for passing the piston rod 7 at the center. The stopper 22 is a disk provided with a through hole at the center for passing the piston rod 7, and a plurality of communication holes 22 c communicating front and rear in the direction of the axis L are provided apart from each other in the circumferential direction.

  A valve seat 20, a collar 23, a stopper 22, and a washer 24 are fitted in this order from the proximal end side (right side in the figure) of the piston rod 7, and a nut 25 is screwed into a male screw 7a formed at the distal end of the piston rod 7. They are tightened together. With this configuration, the valve seat 20 abuts against the large-diameter stepped portion 7b formed on the piston rod 7, and the valve seat 20, the collar 23, the stopper 22, and the washer 24 are disposed between the stepped portion 7b and the nut 25. It is pinched and fixed.

  The valve element 21 of the water-absorbing valve 14 includes a substantially cylindrical piston packing 21a that slides on the inner peripheral surface of the cylinder 3 and a substantially cylindrical packing metal 21b that holds the piston packing 21a. The valve element 21 is loosely fitted to the outside of the collar 23 between the valve seat 20 and the stopper 22, and is movable in the direction of the axis L. Note that another elastic body having a sealing function may be used instead of the piston packing 21a.

  The cylinder tip fitting 4 is arranged on the front side of the cylinder 3 in the direction of the axis L. A discharge port 17 for discharging a liquid is provided at an upper portion of the cylinder tip metal fitting 4.

  A discharge valve 15 is provided inside the cylinder fitting 4 and at the tip of the pump chamber 13 so as to face the pump chamber 13. The discharge valve 15 opens and closes a discharge flow path in accordance with pressurization / decompression of the pump chamber 13 by the pump action of the water absorption valve 14, and discharges the liquid in the pump chamber 13 to the outside through the discharge port 17.

  The discharge valve 15 has a substantially cylindrical valve seat 30, a valve element 31 that opens / closes a discharge flow path by separating / contacting the valve seat 30, and biases the valve element 31 toward the valve seat 30. It comprises a compression coil spring 32 and a valve sack 33 configured in a cup shape so as to cover the valve element 31 from the right side in the figure. The valve element 31 is arranged on the front side of the valve seat 30 and separates / contacts (ie, separates / seizes) with respect to a seat surface 42a (a front end portion; see FIG. 3) of the valve seat 30. As shown in FIG. 2, the compression coil spring 32 is housed inside the valve sack 33. The rear end of the compression coil spring 32 is engaged with the valve element 31, and the front end is supported by a valve sack 33. A plurality of discharge holes 33a are provided in the peripheral wall of the valve sack 33.

  Note that a pressure regulating valve and a pressure regulating handle (not shown) for adjusting the pressure of the liquid discharged from the discharge port 17 may be provided downstream of the discharge valve 15 of the cylinder tip fitting 4. The cylinder fitting 4 may be provided with an air chamber (not shown) for buffering the pulsation of the liquid from the discharge valve 15.

  Subsequently, a holding structure of the cylinder 3 with respect to the cylinder base metal fitting 2 and the cylinder tip metal fitting 4 will be described in detail. The cylinder 3 is sandwiched and fixed between the cylinder base metal fitting 2 and the cylinder tip metal fitting 4 by the connecting means such as the cylinder bolt described above.

  In the forced valve type piston pump P, the cylinder base metal fitting 2 and the cylinder tip metal fitting 4 are shared with the cylinder base metal fitting and the cylinder tip metal fitting used in the conventional forced valve type piston pump, respectively. That is, the cylinder base metal fitting 2 and the cylinder tip metal fitting 4 in the forced valve type piston pump P are the same parts as those in the related art. The inner diameter of the cylinder 3 is enlarged while the cylinder base metal fitting 2 and the cylinder tip metal fitting 4 are shared. Thereby, the internal space S of the cylinder 3 is increased.

  As shown in FIG. 1, the cylinder 3 is connected to the cylinder base 2 via a connection pipe 36. A cylindrical connecting pipe 36 is fitted in a circular hole 2 a provided in the front part of the cylinder base metal fitting 2, and is fitted in a rear end 3 a of the cylinder 3. By disposing the cylinder 3 on the outer peripheral side of the connecting pipe 36, the inner diameter of the cylinder 3 is substantially equal to the diameter of the hole 2a. As shown in FIG. 5, the inner diameter of the cylinder 3 shown in FIG. 1 is larger than that of the conventional cylinder 110 inserted into the hole 102a of the cylinder base 102.

  On the other hand, the cylinder 3 is connected to the cylinder fitting 4 via the valve seat 30 of the discharge valve 15. As shown in FIG. 2, the valve seat 30 is attached to a rear end portion 4 a of the cylinder tip fitting 4. The valve seat 30 is fitted in a first hole 4b and a second hole 4d provided in a rear end 4a of the cylinder tip fitting 4. The valve seat 30 has a first cylindrical portion (cylindrical portion) 41 which is disposed in the first hole portion 4b and is fitted to the rear end portion 4a of the cylinder tip fitting 4, and a distal end side of the first cylindrical portion 41. And a second cylindrical portion 42 formed and arranged in the second hole 4d. The diameter of the second hole 4d is smaller than the diameter of the first hole 4b, and accordingly, the outer diameter of the second cylindrical portion 42 is smaller than the outer diameter of the first cylindrical portion 41. ing. The first tubular portion 41 is fitted in the first hole 4b, and the second tubular portion 42 is fitted in the second hole 4d.

  The first cylindrical portion 41 protrudes rearward in the direction of the axis L from the rear end 4 a of the cylinder tip fitting 4, and the protruding portion is fitted into the front end 3 b of the cylinder 3. With this configuration, the front end 3 b of the cylinder 3 is supported by the valve seat 30. By arranging the cylinder 3 on the outer peripheral side of the first cylindrical portion 41, the inner diameter of the cylinder 3 is substantially equal to the diameter of the first hole 4b. As shown in FIG. 5, the inner diameter of the cylinder 3 shown in FIGS. 1 and 2 is larger than that of the conventional cylinder 110 inserted into the hole 104a of the cylinder tip fitting 104.

  As shown in FIGS. 2 and 3, an annular step portion 41 c is formed between the first tubular portion 41 and the second tubular portion 42. The step portion 41c is abutted in the direction of the axis L against an annular step portion 4c formed between the first hole portion 4b and the second hole portion 4d of the cylinder fitting 4.

  The first cylindrical portion 41 is disposed on the rear side in the axis L direction with respect to the rear end portion 4a of the cylinder tip fitting 4, and has an annular flange portion 43 facing the end surface 4e of the rear end portion 4a; An annular support portion 44 extending rearward in the direction of the axis L with respect to the reference numeral 43. In the present embodiment, the annular support portion 44 is fitted into the front end 3 b of the cylinder 3 to support the cylinder 3. In other words, the front end 3 b of the cylinder 3 surrounds the annular support 44. The front end 3 b of the cylinder 3 is in contact with the rear surface 43 a of the flange 43.

  On the other hand, as shown in FIG. 2, an annular gap G is provided between the flange 43 and the end surface 4 e of the rear end 4 a of the cylinder fitting 4. More specifically, as shown in FIG. 3, the length A between the rear surface 43 a of the flange portion 43 and the step portion 41 c of the first tubular portion 41 in the direction of the axis L is the thickness B of the flange portion 43. And the length C between the step portion 4c and the end face 4e of the cylinder tip fitting 4 is larger than the sum of the length C and the length C. That is, the relationship of A> B + C holds. A gap G is formed between the front surface 43b of the flange 43 and the end surface 4e of the cylinder fitting 4 by the step 41c of the first tubular portion 41 abutting against the step 4c of the cylinder fitting 4. I have.

  By providing the above-mentioned gap G, a tool for removing the discharge valve 15 can be easily inserted between the valve seat 30 and the cylinder end fitting 4. This facilitates disassembly of the cylinder 3 and the valve seat 30 with respect to the cylinder tip fitting 4, and improves the maintainability of the forced valve type piston pump P.

  A first seal groove 41a is formed on the outer peripheral surface of the annular support portion 44, and a first seal member 51 such as an O-ring is provided in the first seal groove 41a. The first seal member 51 seals between the front end 3b of the cylinder 3 and the annular support portion 44 to prevent leakage of liquid. A second seal groove 41b is formed on the outer peripheral surface of the first cylindrical portion 41, and a second seal member 52 such as an O-ring is provided in the second seal groove 41b. The second seal member 52 seals between the rear end portion 4a of the cylinder tip metal member 4 and the first cylindrical portion 41 to prevent leakage of liquid.

  The first tubular portion 41 of the valve seat 30 is formed with a tapered liquid guide hole 46 communicating with the internal space S of the cylinder 3. The liquid guide hole 46 is formed around the axis L, has a truncated cone shape, and is reduced in diameter toward the front side. The liquid introduction hole 46 forms at least a part of the pump chamber 13.

  As shown in FIG. 1, a third seal such as an O-ring is also provided between the connecting pipe 36 and the cylinder base 2 and between the connecting pipe 36 and the rear end 3 a of the cylinder 3. A member 37 and a fourth seal member 38 are provided.

  Next, the operation of the forced valve type piston pump P will be described. When the crankshaft 5 is driven by the power of the prime mover, the piston rod 7 is reciprocated via the connecting rod 6. When the piston rod 7 reciprocates in the cylinder 3, the water absorption step and the discharge step are repeated.

  As shown in FIG. 4 (a), in the water absorption process in which the piston rod 7 moves from the top dead center to the bottom dead center, the stopper 22 comes into contact with the valve body 21 and the valve including the piston packing 21a and the packing fitting 21b is provided. The body 21 is taken to the bottom dead center side. The volume of the internal space S of the cylinder 3 on the front side (the right side in the figure) of the valve body 21 increases, and the internal space S becomes negative pressure. Due to this negative pressure, the liquid flowing into the space on the rear side (left side in the figure) of the valve element 21 flows into the internal space S on the front side of the valve element 21 through the communication hole 22 c of the stopper 22. Since the inner diameter of the cylinder 3 is increased by the cylinder 3 being supported by the valve seat 30, the internal space S of the cylinder 3 is increased, and the amount of liquid flowing into the internal space S can be increased. It is possible.

  On the other hand, as shown in FIG. 4B, in the discharge step in which the piston rod 7 moves from the bottom dead center to the top dead center, the valve seat 20 comes into contact with the valve body 21, and the piston packing 21a and the packing fitting 21b are provided. Is driven to the top dead center side. The internal space S of the cylinder 3 at the front side (the right side in the figure) of the valve body 21 is pressurized, and the liquid flowing into the internal space S is opened to the valve body 31 and sent out through the discharge hole 33a and the discharge port 17. . Since the liquid introduction hole 46 is tapered, the pipeline resistance is reduced. Further, the volume of the space on the rear side (left side in the figure) of the valve element 21 is increased, and the space becomes negative pressure. The liquid flows in from here through the water inlet 16. Thus, the water absorption step and the discharge step are repeated.

  According to the forced valve type piston pump P, the valve body 31 separates / abuts against the valve seat 30 attached to the rear end portion 4a of the cylinder end fitting 4 by the pump action of increasing / decreasing the pressure in the pump chamber 13. The liquid is discharged through the discharge channel. The first cylindrical portion 41 of the valve seat 30 protruding rearward from the rear end 4a of the cylinder tip metal fitting 4 is fitted into the front end 3b of the cylinder 3, and the front end 3b of the cylinder 3 is supported by the valve seat 30. Have been. The first cylindrical portion 41 of the valve seat 30 is made to protrude from the cylinder end fitting 4, and the cylinder 3 is arranged on the outer peripheral side of the first cylindrical portion 41, so that the first hole 4 b formed in the cylinder end fitting 4 is formed. The diameter of the cylinder 3 can be increased without being restricted by the dimensions of the (mounting portion). Thereby, the volume of the internal space S of the cylinder 3 can be increased. As a result, it is possible to increase the water absorption in the forced valve type piston pump P. Moreover, it is only necessary to change the valve seat 30 of the discharge valve 15, and it is not necessary to change the cylinder tip fitting 4. Therefore, the cylinder fitting 4 can be shared with the cylinder fitting originally used. Since it is not necessary to use a separate metal fitting for connecting the cylinder tip metal fitting 4 and the cylinder 3, an increase in the number of parts and an increase in cost are suppressed.

  Furthermore, since the cylinder 3 and the cylinder base 2 are connected via the connecting pipe 36, there is no need to change the cylinder base 2 as well. The cylinder base 2 can be shared with the cylinder base originally used.

  At the time of maintenance or the like, the discharge valve 15 can be easily removed by inserting a tool into the gap G (see FIG. 2) between the end surface 4e of the rear end portion 4a of the cylinder end fitting 4 and the flange 43. Thereby, maintainability is improved. Conventionally, the cylinder was inserted into the cylinder tip fitting and fitted, so there was no space for inserting a tool, and it was difficult to remove it during maintenance. However, this problem has been solved with the forced valve type piston pump P. I have.

  Since the liquid guide hole 46 formed in the valve seat 30 is tapered, the shape change is small, and the pipe resistance in the discharge process is reduced.

  The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in the valve seat 30, the flange 43 may be omitted. The front end 3b of the cylinder 3 surrounding the first tubular portion 41 may abut on the end face 4e of the cylinder fitting 4, or may face the end face 4e with a gap between the end face 4e.

  The liquid guide hole 46 is not limited to a tapered shape. The inner diameter of the liquid guide hole 46 may be constant in the direction of the axis L, or the inner diameter of the liquid guide hole 46 may be reduced stepwise.

  The present invention is not limited to the case where the present invention is applied to the forced valve type piston pump P. The reciprocating member reciprocates in the cylinder in accordance with the driving of the driving unit housed in the driving unit case, thereby performing a pumping operation for pressurizing / depressurizing a pump chamber formed on the front side in the axial direction of the cylinder. The present invention is applicable to any reciprocating pump provided with a valve that opens / closes a flow path when a valve element is separated / seated from a valve seat. INDUSTRIAL APPLICABILITY The present invention is applicable to all types of piston pumps used in agricultural power sprayers or cleaning machines.

  2 ... Cylinder base metal, 3 ... Cylinder, 3b ... Cylinder front end, 4 ... Cylinder tip metal, 4a ... Rear end, 4c ... Step, 4e ... End face, 7 ... Piston rod (reciprocating member), 13 ... Pump chamber, 14: water intake valve, 15: discharge valve, 16: water intake port, 17: discharge port, 30: valve seat, 31: valve body, 32: compression coil spring, 33: valve sack, 41: first cylindrical shape Part (cylindrical part), 41c step part, 42 second cylinder part, 42a seat surface (front end), 43 flange part, 44 annular support part, G clearance, L axis, P axis Forced piston piston pump, S: Internal space of cylinder.

Claims (3)

A pump that pressurizes / depressurizes a pump chamber (13) formed on the front side of the cylinder (3) in the direction of the axis (L) by the reciprocating member (7) reciprocating in the cylindrical cylinder (3). In the reciprocating pump (P) performing the action,
A cylinder fitting (4) arranged on the front side of the cylinder (3) in the direction of the axis (L);
A discharge valve (15) arranged inside the cylinder tip fitting (4) to open and close a discharge flow path;
The discharge valve (15)
A cylindrical valve seat (30) attached to a rear end (4a) of the cylinder tip fitting (4) and supporting a front end (3b) of the cylinder (3);
A valve element which is arranged on the front side of the valve seat (30) in the direction of the axis (L) and separates / contacts a front end (42a) of the valve seat (30) to open and close the discharge flow path ( 31) and
The first valve seat (30) fits into the rear end (4a) of the cylinder tip fitting (4) and projects from the rear end (4a) rearward in the axis (L) direction . A cylindrical portion (41) formed on the tip end side of the first cylindrical portion (41) and having an outer diameter smaller than that of the first cylindrical portion (41) and including the front end portion (42a); And two cylindrical portions (42) ;
The rear side of the first tubular portion (41) of the valve seat (30) is fitted into the front end (3b) of the cylinder (3), and the cylinder (3) is inserted by the valve seat (30). Is supported at the front end (3b) .
A front side portion of the first tubular portion (41) and the second tubular portion (42) of the valve seat (30) are formed with a first hole (4b) formed in the cylinder fitting (4). And a second hole (4d) having a diameter smaller than that of the first hole (4b), and is inserted between the first cylindrical portion (41) and the second cylindrical portion (42). The annular step (41c) formed in the first hole (4b) and the annular step (4c) formed between the second hole (4d) are aligned with the axis. A reciprocating pump that is abutted in the (L) direction . The first cylindrical portion (41) of the valve seat (30) is disposed on the rear side of the rear end portion (4a) of the cylinder tip fitting (4) in the direction of the axis (L), and A flange portion (43) facing the end surface (4e) of the end portion (4a); and a rear end portion of the cylinder (3) extending rearward in the axis (L) direction beyond the flange portion (43). 3b) an annular support portion (44) which is the rear side portion to be fitted into
The reciprocation according to claim 1, wherein a gap (G) is provided between the end surface (4e) of the rear end portion (4a) of the cylinder fitting (4) and the flange portion (43). Dynamic pump. The first cylindrical portion (41) of the valve seat (30) communicates with the internal space (S) of the cylinder (3) and forms at least a part of the pump chamber (13). The reciprocating pump according to claim 1, wherein a tapered liquid guide hole (46) having a diameter reduced toward a front side in the L) direction is formed.

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