JP5147581B2 - Reciprocating pump - Google Patents

Description

  The present invention relates to a reciprocating pump.

  2. Description of the Related Art Conventionally, a reciprocating pump is known in which a reciprocating member reciprocates in a cylinder unit according to driving of a driving unit to perform a pumping action of a liquid such as water in a pump chamber formed on the tip side in the cylinder unit. (For example, refer to Patent Document 1). In such a reciprocating pump, a high pressure seal (seal packing) for preventing liquid from leaking from the pump chamber side to the drive unit side from the pump chamber side in the cylinder unit to the drive unit side, A low-pressure seal (seal packing) and an oil seal for sealing the drive unit lubricating oil are provided so as to be in fluid-tight sliding contact with the reciprocating member in this order.

  Here, if the low-pressure seal causes liquid leakage due to wear or seizure, the liquid easily enters the drive unit from the oil seal, and the lubricating oil is contaminated and deteriorated, losing lubricity, and seizure occurs at the drive unit. This may cause damage to the pump.

Therefore, in Patent Document 1, in order to prevent leakage liquid from entering the drive unit, a seal presser (seal) that is disposed between the low pressure seal and the oil seal and presses and fixes the low pressure seal in the axial direction. There is disclosed a configuration in which an annular partition plate that coaxially surrounds a reciprocating member with a predetermined gap of 1 mm or less (preferably 0.5 mm or less) is provided in the packing retainer, and the leaked liquid is scraped off by the partition plate.
Japanese Patent No. 399594

  As described above, in the reciprocating pump including the above-mentioned publication, it is required to prevent the leaked liquid from entering the drive unit, and an optimum mode is required.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a reciprocating pump that can easily prevent leaked liquid from entering a drive unit.

In the reciprocating pump (100) according to the present invention, the reciprocating member (1) reciprocates in the cylinder part (6) in accordance with the drive of the driving part (7, 8, 9). A reciprocating pump (100) that performs a pumping action in a pump chamber (10) formed on the front end side of the reciprocating member, and is disposed on the drive part (7, 8, 9) side in the cylinder part (6) and is a reciprocating member. An oil seal (26) that is in fluid-tight sliding contact with (1), and a low-pressure seal (21) that is disposed on the pump chamber (10) side in the cylinder portion (6) and is in fluid-tight sliding contact with the reciprocating member (1). The reciprocating pump (100) provided with a dust seal (27) is provided between the oil seal (26) and the low pressure seal (21) in the cylinder part (6), and the dust seal (27) Sliding member (1) slidingly contacts low pressure seal (21) during reciprocating The reciprocating member (1) is located between the low-pressure seal (21) and the dust seal (27) and protrudes radially outward from the drive unit (7, 8, 9) side of the range. (17), and when the reciprocating member (1) is retracted to the maximum, it has a communication path (28d) between the flange (17) and the dust seal (27). It is characterized by.

  According to such a reciprocating pump (100), the pump chamber (10) side that is in fluid-tight sliding contact with the reciprocating member (1) in the cylinder portion (6) where the reciprocating member (1) reciprocates. Since the dust seal (27) is provided between the low pressure seal (21) and the oil seal (26) on the drive unit (7, 8, 9) side, the low pressure seal (21) is directed to the oil seal (26). The leaked liquid is satisfactorily blocked by the dust seal (27), so that the leaked liquid can be easily prevented from entering the drive unit (7, 8, 9).

  Here, when the dust seal (27) is positioned in a sliding contact range with the low pressure seal (21) when the reciprocating member (1) is reciprocated, the reciprocating member (1) is connected to the low pressure seal (21). For example, when a concave portion or a flaw due to wear or the like occurs in the sliding contact portion, there is a risk that leaked liquid may leak to the oil seal (26) through the gap between the concave portion or the flaw and the dust seal (27).

Therefore, the dust seal (27), reciprocating member (1) is located in sliding contact with the drive unit from sliding range (7,8,9) side to the low pressure seal (21) during reciprocation, Ya recess Since scratches are located closer to the pump chamber (10) than the dust seal (27), the leaked liquid is always blocked by the dust seal (27), further preventing the leaked liquid from entering the drive unit (7, 8, 9). Is done. In addition, when the reciprocating member (1) is retracted to the maximum, a reciprocating member (28d) is provided between the flange (17) and the dust seal (27). Leaked liquid is sent to the dust seal (27) side by the retreat of the collar part (17) due to the retreat of 1), and when the reciprocating member (1) is retracted to the maximum, the dust seal (27) by the collar part (17). The leaked liquid sent to the side is discharged to the outside through the communication path (28d) between the flange (17) and the dust seal (27). For this reason, the approach of the leaked liquid to the drive unit (7, 8, 9) is further prevented.

Further, the reciprocating member (1) is between Da Sutoshiru (27) and an oil seal (26) and has a communication passage with the outside (29 b), for example, damage and leakage of the dust seal (27) When leaked liquid leaks from the dust seal (27) due to a large amount of liquid or the like, the leaked liquid passes through the communication path (29b) between the dust seal (27) and the oil seal (26). Is discharged to the outside. For this reason, the approach of the leaked liquid to the drive unit (7, 8, 9) is further prevented.

  Thus, according to the present invention, it is possible to provide a reciprocating pump that can easily prevent the leaked liquid from entering the drive unit.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a reciprocating pump according to the invention will be described with reference to the accompanying drawings. 1 is a longitudinal sectional view showing a reciprocating pump according to an embodiment of the present invention, FIG. 2 is a partially sectional plan view of the reciprocating pump shown in FIG. 1, and FIG. 3 is an enlarged view of the main part of FIG. It is a longitudinal cross-sectional view shown. The upper part from the center line A of the reciprocating member 1 shown in FIG. 1 shows the case where the reciprocating member 1 is at the top dead center, and the lower part shows the case where the reciprocating member 1 is at the bottom dead center.

  As shown in FIGS. 1-3, the reciprocating pump 100 comprises three reciprocating members 1 having a plunger 1a and a plunger sleeve 1b attached to the tip of the plunger 1a (see FIG. 2). It is a reciprocating pump of the type, and its outer shape is configured by connecting a crankcase 2 and a manifold 3 via a cylinder base metal fitting 4.

  Specifically, as shown in FIGS. 1 and 3, a seal washer 18 is inserted with a washer 16 and a cup washer 17 between the plunger 1 a and the plunger sleeve 1 b. The hexagon bolt 19 is screwed into the plunger 1a through the plunger sleeve 1b, whereby the plunger 1a and the plunger sleeve 1b are connected to form the reciprocating member 1, and as shown in FIGS. The hexagon socket head cap screws 5 are respectively screwed into the crankcase 2 through the manifold 3 and the cylinder base metal 4, whereby the manifold 3 and the crankcase 2 are connected.

  In addition, three cylinder portions 6 that form a cylindrical shape and extend in the left-right direction in the figure are arranged inside the manifold 3, the cylinder base bracket 4, and the crankcase 2 (see FIG. 2). The reciprocating members 1 are arranged in the part 6.

  Inside the crankcase 2, a crankshaft 7, a connecting rod 8, and a piston pin 9 that constitute a drive unit of the reciprocating member 1 are arranged. When the crankshaft 7 rotates, the connecting rod 8 and the piston pin 9 are interposed. The reciprocating member 1 reciprocates in the left-right direction in the figure in the cylinder portion 6, and the pump chamber 10 formed on the tip side in the cylinder portion 6 is pressurized / depressurized by the reciprocating member 1. Yes.

  Specifically, as shown below the center line A in FIG. 1, when the reciprocating member 1 moves toward the crankshaft 7, the pump chamber 10 is depressurized and the suction valve 11 provided in the manifold 3. The valve body 11a and the valve body 12a of the discharge valve 12 are opened and closed, respectively, and the liquid used is sucked from the suction port 13 provided in the manifold 3 into the pump chamber 10 through the flow path of the suction valve 11. As shown above the center line A in FIG. 1, when the reciprocating member 1 moves toward the side opposite to the crankshaft 7, the pump chamber 10 is pressurized, and the valve body 11 a and the discharge valve 12 of the intake valve 11. The valve body 12a is closed and opened, and the liquid used in the pump chamber 10 is discharged through the flow path of the discharge valve 12 to the discharge port 14 provided in the manifold 3 to suck and discharge the used fluid. It is configured to act There. As shown in FIGS. 1 and 2, the suction valve 11 and the discharge valve 12 are respectively attached to the manifold 3 in a state of being plugged by a plug 15.

  Further, in the cylinder portion 6, an annular shape is used to prevent the working fluid from being transmitted between the reciprocating member 1 (plunger sleeve 1 b) that reciprocates and leaking from the pump chamber 10 side to the crankcase 2 side. The high-pressure seal 20 and the low-pressure seal 21 are provided in this order from the pump chamber 10 side so as to be in fluid-tight sliding contact with the outer peripheral surface of the reciprocating member 1. The high-pressure seal 20 and the low-pressure seal 21 are annular bodies including, for example, synthetic rubber. The low pressure seal 21 has an annular shape and is accommodated on the rear side (right side in the figure) of the seal case 22 in which the reciprocating member 1 reciprocates through the cylindrical hole. The high pressure seal 20 is located on the crankcase 2 side from the seal case 22. It is mounted on the manifold 3 by being pressed toward the pump chamber 10 through the seal case 22 by the cylinder base metal 4 disposed in the cylinder. The space between the outer periphery of the seal case 22 and the inner peripheral surface of the manifold 3 is liquid-tightly sealed with an O-ring 25.

  In addition, in a space surrounding the reciprocating member 1 in the seal case 22 and in the annular region 23 on the pump chamber 10 side facing the low pressure seal 21, a part of the used fluid sucked from the suction port 13 is cooled. The reciprocating member 1 that is supplied through the path 24 and reciprocates is cooled by the cooling region 23. Therefore, the low pressure seal 21 prevents leakage of the used liquid in the cooling region 23 to the crankcase 2 side.

  On the other hand, the leaking liquid from the pump chamber 10 side is transmitted to the crankcase 2 between the reciprocating member 1 (plunger 1a) that reciprocates, and the drive unit (crankshaft 7, connecting rod 8, piston pin 9 and the like). And an annular oil seal 26 for sealing so that the lubricating oil of the drive unit does not leak to the low-pressure seal 21 side so as to be in fluid-tight sliding contact with the outer peripheral surface of the reciprocating member 1. Is provided. Here, the oil seal 26 is a multi-lip type with a dust lip.

  Here, particularly in the present embodiment, an annular dust seal 27 is provided between the low pressure seal 21 and the oil seal 26 in the cylinder portion 6 to isolate the low pressure seal 21 side and the oil seal 26 side. Has been. The dust seal 27 is for preventing the liquid leaking from the low pressure seal 21 from moving toward the oil seal 26, and is closer to the drive unit than the sliding contact range where the reciprocating member 1 is in sliding contact with the low pressure seal 21 during the reciprocating motion. It is supposed to be positioned.

  The dust seal 27 is formed in an annular shape and is accommodated on the rear side of the dust seal case 28 in which the reciprocating member 1 reciprocates through the cylindrical hole, and between the rear end surface of the dust seal case 28 and the oil seal 26. Is provided with a seal presser 29 which is formed in an annular shape and in which the reciprocating member 1 reciprocates through the cylindrical hole. The oil seal 26 is attached to the crankcase 2 by being pressed to the drive unit side by the cylinder base metal 4 via the dust seal case 28 and the seal retainer 29. Further, in this state, the dust seal 27 is accommodated in the dust seal case 28 while being accommodated on the rear side in the dust seal case 28 and sandwiched by the seal retainer 29, and the low pressure seal 21 is pumped through the dust seal case 28. It is pressed to the chamber 10 side and is thereby attached to the seal case 22.

  In the dust seal case 28, first liquid drain holes 28 a and 28 b are respectively provided at the upper and lower positions facing the cylinder base metal 4, and the first liquid drain holes 28 a and 28 b in the dust seal case 28 and the dust seal 27 are provided. The second liquid drain holes 28c and 28d are respectively provided at the upper and lower positions with respect to the portion to which the seal is attached, and the third liquid drain holes 29a and 29b are provided at the upper and lower positions of the seal retainer 29, respectively. It has been.

  The liquid drainage holes arranged side by side along the reciprocating direction of these reciprocating members 1 are for discharging the leaked liquid to the outside when the used liquid leaks from the pump chamber 10 side. One liquid drain hole 28a, 28b is a cup washer between the plunger 1a and the plunger sleeve 1b when the reciprocating member 1 is at the top dead center (advance limit) as shown above the center line A in FIG. The second liquid drain holes 28c and 28d are located immediately after the cup 17 and the cup washer 17 when the reciprocating member 1 is at the bottom dead center (retreat limit) as shown below the center line A in FIG. It is arranged to be located immediately after.

  Further, in the present embodiment, the first liquid drain holes 28a and 28b are the largest, then the second liquid drain holes 28c and 28d, and the third liquid drain holes 29a and 29b become smaller in this order. It is set as the structure which has drainage performance.

  Then, as shown in FIG. 3, the first liquid drain holes 28a and 28b of the dust seal case 28 are communicated with the inner peripheral surface of the cylinder base metal fitting 4 facing the dust seal case 28 to assist the discharge of the used liquid. A relief groove 30 is provided along the circumferential direction, and the second liquid drain holes 28c and 28d of the dust seal case 28 are communicated with each other on the inner peripheral surface of the crankcase 2 facing the dust seal case 28. Relief grooves 31 for assisting the discharge of the liquid are provided along the circumferential direction, and third liquid drain holes 29 a of the seal retainer 29 are formed on the inner peripheral surface of the crankcase 2 facing the seal retainer 29. An escape groove 32 is provided along the circumferential direction for communicating the liquids 29b and assisting the discharge of the used liquid. Further, the first, second, and third liquid vent holes 28b, 28d at the bottom are provided. A portion of the cylinder base metal fitting 4 and a portion of the crankcase 2 positioned below 29b are formed as recesses and cutouts communicating with the outside, and these liquid drain holes 28a to 28d, 29a and 29b, relief grooves 30 to 32, A communication path with the outside is configured by the recesses, notches and the like. Accordingly, the liquid vent holes 28a, 28c, 29a at the respective upper positions function as sufficient air vent and overflow of leaked liquid.

  The dust seal 27, dust seal case 28, seal retainer 29, cup washer 17, washer 16, plunger 1 a, plunger sleeve 1 b, seal washer 18, hexagon bolt 19, cylinder base bracket 4, hexagon socket head bolt 5, etc. The dust seal case 28 with the dust seal 27 inserted is inserted into the crankcase 2 and the seal retainer 29 is sandwiched between the oil seal 26 and then the cup washer 17, the washer 16, and the plunger sleeve 1b are sealed. The plunger assembly 1 is fixed to the plunger 1a by the washer 18 and the hexagon bolt 19, and then the dust seal case 28 is pressed by the cylinder base metal 4, and then the manifold assembly with the intake valve 11, the discharge valve 12, the plug 15 and the like is attached to the plunger sleeve 1b. Extrapolating cylinder base bracket 4 By fixing the manifold assembly to the crankcase 2 by hexagon socket head cap screw 5 in a state sandwiched between the Kukesu 2, so that the reciprocating pump 100 can be easily obtained.

  In such a reciprocating pump 100, when the use liquid leaks from the low pressure seal 21, the leaked liquid is first dust-sealed from the cup washer 17 by the cup washer 17 projecting annularly outward in the radial direction. The liquid is discharged to the outside through the first liquid drain hole 28b in the lower part of the dust seal case 28 while being prevented from being blocked and blocked from flowing out to the 27th side.

  Further, when a large amount of leaked liquid overflows the cup washer 17, the water scavenging effect by the reciprocating movement of the cup washer 17 (when moving forward, the leaked liquid is poured into the first liquid drain hole 28 b on the lower side on the front side. In the case of pushing and retreating, the leaked liquid is pushed into the lower second liquid drain hole 28d on the rear side), so that the leaked liquid becomes the first and second liquid drain holes 28b on the lower part of the dust seal case 28. It is discharged outside through 28d.

  Next, when the amount of leakage further increases and discharge from the lower first and second liquid drain holes 28b, 28d cannot catch up and the liquid level in the dust seal case 28 rises, the dust seal 27 prevents the leakage liquid from entering. The leaked liquid is discharged from the lower portion to the outside through the escape grooves 30 and 31 from the first and second liquid drain holes 28a and 28c in the upper portion.

  Further, when the amount of leakage becomes large, or the dust seal 27 is damaged and the used liquid leaks from the dust seal 27 to the oil seal 26, first, the leaked liquid is the third liquid drain hole at the lower part of the seal retainer 29. The leaked liquid is discharged to the outside through 29b, and further, the oil seal 26 prevents the leaked liquid from entering, while the leaked liquid escapes from the upper third liquid drain hole 29a and is discharged to the outside through the groove 32.

  Further, when the leakage becomes further severe and the sealing presser 29 is filled with the leakage liquid, the multiple lip type oil seal 26 with dust lip prevents leakage to the drive unit side for a short time.

  As described above, in the present embodiment, the low pressure seal 21 on the pump chamber 10 side that is in fluid-tight sliding contact with the reciprocating member 1 in the cylinder portion 6 in which the reciprocating member 1 reciprocates and the drive portion side are provided. Since the dust seal 27 is provided between the oil seal 26 and the leaked liquid from the low-pressure seal 21 toward the oil seal 26 is well blocked by the dust seal 27, the leaked liquid can easily enter the drive unit. It is prevented.

  Further, since the dust seal 27 is positioned closer to the driving unit than the sliding contact range in which the reciprocating member 1 is in sliding contact with the low pressure seal 21 during the reciprocating motion, the reciprocating member 1 is worn, for example, at a sliding contact position with the low pressure seal 21. If a recess or a flaw due to the above is generated, the recess or the flaw is located on the pump chamber 10 side with respect to the dust seal 27. Therefore, the leaked liquid is always blocked by the dust seal 27 (the leaked liquid is In other words, the leakage liquid does not leak to the drive unit side through a scratch or the like), and entry of leaked liquid into the drive unit is further prevented.

  The reciprocating member 1 has a cup washer 17 as a flange that is located between the low-pressure seal 21 and the dust seal 27 and protrudes radially outward, and between the dust seal 27 and the oil seal 26, a third The liquid leakage hole 29b is connected to the outside and the leakage fluid from the low pressure seal 21 is first blocked by the cup washer 17 of the reciprocating member 1, and then the cup. When the leaked liquid leaks from the dust seal 27 due to, for example, damage to the dust seal 27 or a large amount of leaked liquid after passing over the washer 17, the leaked liquid is separated between the dust seal 27 and the oil seal 26. By the communication path with the outside including the third liquid drain hole 29b in between, the liquid is discharged to the outside, and the leaked liquid is further prevented from entering the drive unit.

  Further, when the reciprocating member 1 is retracted to the maximum, a communication path to the outside including the second liquid drain hole 28d is provided between the cup washer 17 and the dust seal 27 which are the flanges. Therefore, the leaked liquid is sent to the dust seal 27 side by the backward movement of the cup washer 17 due to the backward movement of the reciprocating member 1, and is sent to the dust seal 27 side by the cup washer 17 when the reciprocating member 1 is retracted to the maximum. The leaked liquid is discharged to the outside by the communication path to the outside including the second liquid drain hole 28d between the cup washer 17 and the dust seal 27, and the leaked liquid is further prevented from entering the drive unit. ing.

  In addition, as described above, even if the user finds leakage of the used liquid, maintenance can be performed because it is possible to prevent the use liquid from entering the drive unit for a short period of time and there is no need to stop the operation immediately. There is also an effect that the reciprocating pump 100 can be used with peace of mind.

  In addition, according to this embodiment, compared with the case where felt packing is arrange | positioned between the low pressure seal 21 and the oil seal 26, components, such as an oil pan, are unnecessary, and an advantage that size reduction can be achieved. is there.

  FIG. 4 is a longitudinal sectional view showing a reciprocating pump according to another embodiment of the present invention. The same elements as those of the previous embodiment are denoted by the same reference numerals, and description thereof is omitted here. In addition, in this figure, the upper part of the center line A of the reciprocating member 31 having the plunger 31a and the plunger sleeve 31b attached to the tip of the plunger 31a is the bottom dead center of the reciprocating member 31. A case where the lower part is the top dead center of the reciprocating member 31 is shown.

  In the reciprocating pump 200 of this embodiment, the crankcase 32 and the manifold 33 are directly connected to form an outer shape, and the reciprocating member 31 reciprocates. An annular high pressure seal 40 and a low pressure seal 41 disposed toward the right side in the drawing are in fluid-tight sliding contact with the plunger sleeve 31b, and an annular oil seal 46 disposed on the drive unit side from the low pressure seal 41. Is in a liquid-tight sliding contact with the plunger 31a, and an annular dust seal 47 is disposed between the low pressure seal 41 and the oil seal 46, and an annular dust seal 47 is provided from the pump chamber side toward the drive unit side. An annular dust seal case 49 that houses the seal retainer 48 and the dust seal 47 and contacts the oil seal 46 is disposed. An annular seal retainer 50 is disposed between the seal 46 and the inner peripheral surface of the rear end portion of the dust seal case 49. The low pressure seal 41 is connected to the pump chamber by the seal retainer 48 and the dust seal case 49. The oil seal 46 is pressed to the drive unit side and is attached to the crankcase 32, and the dust seal is pressed by the seal presser 50 between the oil seal 46 and the dust seal 47. 47 is pressed to the pump chamber side and attached to the dust seal case 49.

  First liquid drain holes 48a and 48b are provided at the upper and lower positions of the seal retainer 48 on the pump chamber side, and third liquid drain holes 50a and 48b are disposed at the upper and lower positions of the seal retainer 50 on the drive unit side. 50 b are provided, and third liquid drain holes 49 a and 49 b that overlap the third liquid drain holes 50 a and 50 b are respectively provided at the upper and lower positions of the dust seal case 49.

  As in the previous embodiment, a relief groove that connects the upper and lower liquid drain holes, a recess or notch that communicates with the outside, and the like are provided. These liquid drain holes 48a, 48b, 49a, 49b, 50a, The communication path with the outside is configured in the same manner as in the previous embodiment by 50b, the escape groove, the recess, the notch and the like.

  In the reciprocating pump 200 having such a configuration, the leaked liquid is first discharged to the outside from the first liquid drain holes 48a and 48b, and then to the outside from the third liquid drain holes 49a, 49b, 50a and 50b. It will be discharged.

  Even in such a reciprocating pump 200, substantially the same effect as that of the previous reciprocating pump 100 can be obtained. That is, since the dust seal 47 is provided between the low-pressure seal 41 and the oil seal 46, the leaked liquid from the low-pressure seal 41 to the oil seal 46 is well blocked by the dust seal 47, and the drive unit for the leaked liquid Entry to is easily prevented.

  Further, since the dust seal 47 is positioned on the drive unit side from the sliding contact range in which the reciprocating member 31 is in sliding contact with the low pressure seal 41 during the reciprocating motion, the reciprocating member 1 is worn, for example, at a sliding contact position with the low pressure seal 41. When a recess or scratch is generated due to the above, the recess or scratch is located on the pump chamber side with respect to the dust seal 47. Therefore, the leaked liquid is always blocked by the dust seal 47, and is transferred to the drive unit of the leaked liquid. Is further prevented.

  In addition, the reciprocating member 31 has a cup washer 17 as a flange that is located between the low pressure seal 21 and the dust seal 27 and protrudes radially outward, and between the dust seal 47 and the oil seal 46, a third The liquid leakage holes 49 a, 49 b, 50 a, 50 b and the like are connected to the outside so that the leaked liquid from the low pressure seal 41 is first blocked by the cup washer 17 of the reciprocating member 31. Next, when the leaked liquid leaks from the dust seal 47 due to, for example, damage to the dust seal 47 or a large amount of leaked liquid over the cup washer 17, the leaked liquid is separated from the dust seal 47. The liquid is discharged to the outside by a communication passage with the outside including the third liquid drain holes 49a, 49b, 50a, 50b between the oil seal 46 and leaked liquid. Entry into the drive unit is prevented further.

  The present invention has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the plungers 1a and 31a and the plunger sleeves 1b and 31b The cup washer 17 is used to block the leaked liquid from the low pressure seals 21 and 41, but is not limited to the cup washer 17 and is provided in the reciprocating members 1 and 31. In other words, it is only necessary that the flange is located between the low pressure seals 21 and 41 and the dust seals 27 and 47 and protrudes radially outward.

It is a longitudinal cross-sectional view which shows the reciprocating pump which concerns on one Embodiment of this invention. It is a partial cross section top view of the reciprocating pump shown in FIG. It is a longitudinal cross-sectional view which expands and shows the principal part of FIG. It is a longitudinal cross-sectional view which shows the reciprocating pump which concerns on other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,31 ... Reciprocating member, 1a, 31a ... Plunger (reciprocating member), 1b, 31b ... Plunger sleeve (reciprocating member), 6 ... Cylinder part, 7 ... Crankshaft (driving part), 8 ... Connecting rod (driving) Part), 9 ... piston pin (driving part), 10 ... pump chamber, 17 ... cup washer (saddle part), 21, 41 ... low pressure seal, 26, 46 ... oil seal, 27, 47 ... dust seal, 28c, 28d ... Second liquid drain hole (communication path), 29a, 29b, 49a, 49b, 50a, 50b ... Third liquid drain hole (communication path), 100, 200 ... reciprocating pump.

Claims (2)

The reciprocating member (1) reciprocates in the cylinder part (6) according to the drive of the drive part (7, 8, 9), so that the pump chamber (10 formed on the tip side in the cylinder part (6)) ) Is a reciprocating pump (100) that performs a pumping action, and is disposed on the side of the drive part (7, 8, 9) in the cylinder part (6) and is in fluid-tight sliding contact with the reciprocating member (1). A reciprocating pump comprising an oil seal (26) and a low pressure seal (21) disposed on the pump chamber (10) side in the cylinder part (6) and in fluid-tight sliding contact with the reciprocating member (1). (100)
A dust seal (27) is provided between the oil seal (26) and the low pressure seal (21) in the cylinder part (6) ,
The dust seal (27) is positioned closer to the drive unit (7, 8, 9) than a sliding contact range in which the reciprocating member (1) is in sliding contact with the low pressure seal (21) when reciprocating.
The reciprocating member (1) has a flange (17) located between the low pressure seal (21) and the dust seal (27) and projecting radially outward.
When the reciprocating member (1) is retracted to the maximum, a communicating path (28d) with the outside is provided between the flange (17) and the dust seal (27). Reciprocating pump (100). Between the dust seal (27) and said oil seal (26), according to claim 1 Symbol placement reciprocating pump, characterized in that it has a communication passage (29 b) with the outside (100).

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