WO2013152549A1

WO2013152549A1 - Variable plunger piston pump

Info

Publication number: WO2013152549A1
Application number: PCT/CN2012/076051
Authority: WO
Inventors: 张银根
Original assignee: 台州巨力工具有限公司
Priority date: 2012-04-09
Filing date: 2012-05-25
Publication date: 2013-10-17
Also published as: CN102619739B; DE112012000630T5; CN102619739A; DE112012000630B4

Abstract

A variable plunger piston pump comprises a pump body (1), a low-pressure plunger piston (3), and a high-pressure plunger piston (2). The low-pressure plunger piston (3) is arranged in the pump body (1); the pump body (1) is divided, by the low-pressure plunger piston (3), into two independent cavities: an upper cavity (1a) and a lower cavity (1b); a spring (4) is arranged in the lower cavity (1b); two ends of the spring (4) separately act on inner sides of the low-pressure plunger piston (3) and the pump body (1); the high-pressure plunger piston (2) penetrates through the pump body (1); an overflow mechanism is arranged on the low-pressure plunger piston (3); a first oil inlet hole (5) and a first oil outlet hole (6) which are in communication with the upper cavity (1a) are arranged on the pump body (1); a second oil inlet hole (7) and a second oil outlet hole (8) which are in communication with the lower cavity (1b) are further arranged on the pump body (1); a first oil inlet one-way valve (5a), a second oil inlet one-way valve (7a), a first oil outlet one-way valve (6a) and a second oil outlet one-way valve (8a) are respectively arranged at the first oil inlet hole (5), the first oil outlet hole (6), the second oil inlet hole (7) and the second oil outlet hole (8); and the directions of the four one-way valves are all consistent with the flowing direction of oil. The plunger piston pump has advantages such as a simple structure, high oil outlet efficiency, and high stability.

Description

Variable variable displacement piston pump

The invention belongs to the technical field of machinery and relates to a plunger pump, in particular to a variable displacement plunger pump. Background technique

Plunger pumps for low-pressure, high-flow, high-pressure, low-flow, liquid-delivery are widely used in hydraulic tools, hydraulic handling equipment, and lifting equipment. The purpose of setting the plunger pump is to improve the pumping efficiency and high pressure of the plunger pump at low pressure.

In order to achieve the above objectives, Taiwan Patent Office TW401484 provides a "piston pump" which includes a pump body having a slidable plunger in the pump body, the plunger separating the interior of the pump body into two chambers adjacent to each other: The upper cavity and the lower cavity have an oil inlet hole communicating with the lower cavity and an oil outlet communicating with the upper cavity, and the oil inlet hole and the oil outlet hole are respectively provided with a flow direction consistent with the oil flow direction To the valve. A check valve is also provided on the plunger. A spring is disposed in the lower cavity, and the plunger has a tendency to move upward toward the cavity under the action of the spring.

During the operation of the plunger pump, the high pressure plunger at the upper chamber presses the low pressure plunger, and the low pressure plunger opens over the spring force during the downward movement of the spring force, and the oil at the lower chamber enters through the overflow valve. The upper chamber is then discharged by the upper chamber. Conversely, after the high pressure plunger is moved up, the low pressure plunger is reset by the spring force of the spring. During this process, the one-way valve at the oil inlet opens and the oil enters the lower chamber; at the same time, the upper chamber is enlarged. The oil opens the check valve at the oil outlet, and the oil is discharged through the oil outlet.

The reciprocating action described above allows the oil to be continuously discharged from the oil outlet. However, since the oil of the lower chamber enters the upper chamber through the overflow valve when the low pressure plunger moves downward, the plunger is discharged from the oil outlet hole at the upper chamber during the upward movement. In the low pressure state, the amount of pump oil is large during the plunger moving up; the amount of pump oil is less during the plunger pressing process. Formed in a low pressure state, the handle is released, the hydraulic cylinder piston protrudes more, the hydraulic pressure when the handle is pressed The phenomenon that the cylinder protrudes less, which causes the oil to be unbalanced during the low pressure operation, and then suddenly and slowly.

Chinese Patent Publication No. CN102080641A provides a "reciprocating plunger pump oil supply device" which includes a pump body having a piston and a piston separating the pump body into two independent chambers: a left chamber and a right chamber body. The pump body has an oil inlet hole and an oil outlet hole communicating with the left cavity body, and an oil inlet hole 2 and an oil outlet hole 2 communicating with the right cavity body on the pump body. The piston is driven by gears and racks. When the piston moves left and right, the oil outlet hole and the oil outlet hole can continue to flow out. However, when a high pressure state is encountered when applied to a hydraulic tool, the above device suddenly fails to discharge oil.

Similar problems exist with other existing plunger pumps. Summary of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a variable displacement plunger pump which is simple in structure and can quickly realize oil discharge in view of the above problems in the prior art.

The object of the present invention can be achieved by the following technical solutions: a variable displacement piston pump comprising a pump body having a cavity inside, a low pressure plunger and a high pressure plunger, wherein the low pressure plunger is disposed in the pump body and The upper low pressure plunger can divide the interior of the pump body into two independent cavities: an upper cavity and a lower cavity, wherein the lower cavity is provided with a spring and the two ends of the spring respectively act on the low pressure plunger And the inside of the pump body, the high pressure plunger passes through the pump body and the inner end thereof is located in the upper cavity, and the outer end thereof protrudes out of the pump body, wherein the low pressure plunger is arranged An overflow mechanism, the pump body has an oil inlet hole and an oil outlet hole communicating with the upper cavity body, and the pump body further has an oil inlet hole 2 and an oil outlet hole 2 communicating with the lower cavity body, The oil inlet hole 1, the oil inlet hole 2, the oil outlet hole 1 and the oil outlet hole are respectively provided with an oil inlet check valve, an oil inlet check valve 2, an oil discharge check valve 1 and an oil discharge list. To valve two, and the direction of the above four check valves is consistent with the flow direction of the oil.

The applied external force drives the high pressure plunger to move up and down during the low pressure state. The oil hole one and the oil outlet hole can be continuously separated from each other; in the high pressure state, only the oil outlet hole can be separated from the oil, and the oil discharge amount of the oil outlet hole 2 at this time is small relative to the low pressure state.

In the low pressure state, when the high pressure plunger moves up, the low pressure plunger moves up under the action of the spring force. In this process, the overflow mechanism is closed, the oil inlet check valve is opened, and the oil discharge check valve is opened. When the liquid enters the lower cavity through the oil inlet hole 2, the oil in the upper cavity is discharged through the oil outlet hole; when the high pressure plunger moves down, the high pressure plunger overcomes the spring force and then presses the low pressure plunger to move down with the lower pressure plunger. In this process, the overflow mechanism is closed, the oil inlet check valve is opened, and the oil discharge check valve is opened. The oil enters the upper chamber through the oil inlet hole, and the oil in the lower chamber is discharged through the oil outlet hole. .

In the high pressure state, when the high pressure plunger moves up, the low pressure plunger moves up under the spring force of the spring. Due to the high oil pressure at the upper chamber, the low pressure plunger cannot be fully moved with the high pressure plunger. Contact. During this process, the relief valve is closed, the oil inlet check valve is opened, the oil enters the lower chamber through the oil inlet hole 2, and the oil in the upper chamber cannot be discharged; when the high pressure plunger moves down, the high pressure plunger overcomes the spring. After the elastic force, the low pressure plunger is pressed to move downwards. In this process, the overflow mechanism is opened, the oil discharge check valve is opened, and the oil at the upper chamber is discharged through the oil outlet hole.

In the variable displacement piston pump described above, the low pressure plunger side portion has a convex rib, and the spring sleeve is sleeved on the low pressure plunger and one end of the spring abuts against the rim.

The spring is positioned by the rim.

In the above variable displacement piston pump, the low pressure plunger includes a cylindrical body, and the overflow mechanism is a plug and an overflow spring located in the body, and the inside of the body has a seal capable of contacting the plug to form a seal. The sealing portion, the two ends of the overflow spring respectively act on the body and the plug and the plug has a tendency to abut against the sealing portion under the elastic force of the overflow spring.

The overflow mechanism is only open when the high pressure state is high and the high pressure plunger is moved up. Specifically, in this state, the oil in the lower chamber can overcome the elastic force of the overflow spring to disengage the plug from the sealing surface, so that the oil in the lower chamber enters the upper chamber through the overflow mechanism. In the variable displacement piston pump described above, the spring force of the overflow spring is greater than the spring force of the medium spring of the oil discharge check valve one.

Obviously, such a structure allows the overflow mechanism to be opened only when the high pressure state and the high pressure plunger are moved down.

In the above variable displacement piston pump, the body is screwed with a pressure cap, and both ends of the overflow spring act on the pressure cap and the plug respectively, and the pressure cap has an oil hole for circulating oil. .

The overflow spring and plug can be conveniently placed in the low pressure plunger and positioned.

In the variable displacement piston pump described above, the oil passage hole has a "T" shape, and the lower port of the oil passage hole communicates with the lower chamber body, and the two upper ports of the oil passage hole communicate with the upper chamber body.

This arrangement allows the high pressure plunger to be directly pressed against the pressure cap. Since the two upper ports of the oil passage are located on the side of the pressure cap, the high pressure plunger does not hinder the flow of oil.

In the above variable displacement piston pump, the oil inlet check valve 1 and the oil inlet check valve 2 are both located on the pump body side, and the oil discharge check valve 1 and the oil discharge check valve 2 are both located in the pump body. In the variable displacement piston pump described above, the oil inlet hole and the oil outlet hole are both located at the top of the upper chamber.

In the above variable displacement piston pump, the body port has a connecting seat having a large aperture, the end of the pressing cap has an annular protruding stop, and the gap between the blocking head and the body end connecting seat has a gap, The stop head abuts against the connecting seat and the outlets of the above-mentioned oil passing holes are respectively located at two sides of the blocking head.

The connecting seat cooperates with the blocking head so that the upper cavity has as much space as possible. At the same time, the position of the oil inlet hole and the oil outlet hole makes it possible to stably discharge the oil at the upper chamber through the oil outlet hole even if the upper chamber has less oil.

In the above variable displacement plunger pump, a seal ring is provided between the high pressure plunger and the pump body.

In the variable displacement piston pump described above, the pump body has a recessed spring seat, and one end of the spring is located at the spring seat. Compared with the prior art, when the plunger pump of the variable is in a low pressure state, the oil inlet hole and the oil inlet hole can be quickly separated from each other, and the oil outlet hole and the oil outlet hole can be separated by a large amount of oil; When the oil hole is out, a small amount of oil can be separated. That is to say, the low pressure state of the plunger pump is a large amount of oil, and a small amount of oil is produced in a high pressure state. Therefore, the pump efficiency is high and the operation is easy and labor-saving at high pressure, and the efficiency can be improved by about 8 times compared with the ordinary plunger pump.

At the same time, since the oil passage hole of the pressure cap is symmetrically arranged, the pressure cap is not tilted and moved by the center of gravity when being pressed by the high pressure plunger, so that it has high stability and long service life. At the same time, the oil hole on the pressure cap does not come into contact with the high pressure plunger, and its stability is further improved. DRAWINGS

Fig. 1 is a schematic cross-sectional view showing the high pressure plunger moving up when the plunger pump of this variable is in a low pressure state.

Fig. 2 is a schematic cross-sectional view showing the high pressure plunger moving downward when the plunger pump of this variable is in a low pressure state.

Fig. 3 is a cross-sectional structural view showing the high pressure plunger moving up when the plunger pump of the variable is in a high pressure state.

Fig. 4 is a cross-sectional structural view showing the high pressure plunger moving downward when the plunger pump of the variable is in a high pressure state.

Figure 5 is a cross-sectional structural view of a cable cutter having a plunger pump of the present variable.

In the figure, 1, pump body; l _a , upper cavity; lb, lower cavity; lb l, spring seat; 2, high pressure plunger; 3, low pressure plunger; 3a, retaining edge; 3b, body; 3b l 3c, plug; 3d, overflow spring; 4, spring; 5, oil inlet hole 1; 5a, oil inlet check valve one; 6, oil outlet one; 6a, oil outlet check valve 7. Oil inlet hole 2; 7a, oil inlet check valve 2; 8, oil outlet hole 2; 8a, oil outlet check valve 2; 9, pressure cap; 9a, oil hole; 9b, stop head; , oil cylinder; 1 1, oil storage chamber; 12, movable handle; Fixed handle. detailed description

As shown in Figs. 1 and 2, the variable displacement piston pump includes a pump body 1 having a cavity inside, and a pumping body 1 is provided with a low pressure plunger 3 and a high pressure plunger 2.

The low pressure plunger 3 is disposed in the pump body 1 and can slide up and down. The low pressure plunger 3 divides the interior of the pump body 1 into two independent cavities: an upper chamber l a and a lower chamber l b. A spring 4 is disposed in the lower chamber lb, and both ends of the spring 4 act on the inside of the low pressure plunger 3 and the pump body 1, respectively. In this embodiment, the side of the low pressure plunger 3 has a convex rib 3a, the spring 4 is sleeved on the low pressure plunger 3, and one end of the spring 4 abuts against the rib 3a, and the lower cavity lb of the pump body 1 There is a recessed spring seat lb l, and the other end of the spring 4 is located at the spring seat lb l .

The high pressure plunger 2 passes through the pump body 1. The inner end of the high pressure plunger 2 is located in the upper chamber la, and the outer end of the high pressure plunger 2 extends out of the pump body 1. In this embodiment, a seal ring is provided between the high pressure plunger 2 and the pump body 1. The low pressure plunger 3 is provided with an overflow mechanism. The pump body 1 has an oil inlet hole 5 and an oil outlet hole 6 communicating with the upper cavity la, and the pump body 1 further has an oil inlet communicating with the lower cavity lb. The hole 2 and the oil outlet 2, the oil inlet hole 5, the oil inlet hole 2, the oil outlet hole 6 and the oil outlet hole 8 are respectively provided with an oil inlet check valve 5a, oil inlet The check valve 2 7a, the oil discharge check valve 6a and the oil discharge check valve 2 8a, and the directions of the above four check valves are consistent with the flow direction of the oil.

The low pressure plunger 3 includes a cylindrical body 3b, the overflow mechanism is a plug 3c and a overflow spring 3d located in the body 3b, and the inside of the body 3b has a sealing portion capable of contacting the plug 3c to form a seal, and the overflow spring Both ends of 3d act on the body 3b and the plug 3c, respectively, and the plug 3c has a tendency to abut against the seal under the elastic force of the overflow spring 3d. The spring force of the overflow spring 3d is greater than the spring force of the medium spring of the oil check valve 6a.

A pressure cap 9 is screwed onto the body 3b, and both ends of the overflow spring 3d act on the pressure cap 9 and the plug 3c, respectively, and the pressure cap 9 has an oil passage hole 9a through which the oil flows. The oil hole 9a has a "T" shape, and the lower port of the oil hole 9a communicates with the lower chamber lb, and the two upper ports of the oil hole 9a communicate with the upper chamber la.

The oil inlet check valve 5a and the oil inlet check valve 2a are located on the pump body 1 side, and the oil discharge check valve 6a and the oil discharge check valve 2a are located on the other side of the pump body. The oil inlet hole 5 and the oil outlet hole 6 are located at the top of the upper chamber l a. In this embodiment, the body 3b has a connecting seat 3b l having a large aperture at the port, the end of the pressing cap 9 has an annular protruding head 9b, and the gap between the blocking head 9b and the end connecting seat 3b of the body 3b has a gap. The stopper 9b abuts against the joint 3b and the outlet of the above-mentioned oil passage 9a is located on both sides of the stopper 9b.

As shown in Fig. 5, the variable displacement piston pump can be used in a hydraulic wire crimping tool or a cable cutting tool. The crimping die of the hydraulic wire crimping tool must first advance without load and then contact the pressed terminal. During the no-load motion, the hydraulic pump only needs to overcome the spring and frictional resistance of the hydraulic cylinder, and the required pressure is small. At this time, in order to increase the moving speed of the piston, it is possible to supply oil to the hydraulic cylinder at a large flow rate. When the piston pushes the crimping die into contact with the pressed terminal, it is necessary to overcome the resistance generated by the deformation of the wire end, and a large pressure is required. The piston can be slowly advanced to reduce the impact of the piston on the hydraulic cylinder and the working head. At the same time, it can be achieved easily and effortlessly.

The cable cutting tool is also the above principle, which includes a variable displacement piston pump, a cylinder 10 and an oil storage chamber 11. The variable displacement piston pump is fixedly connected to the oil storage chamber 1 1 , and the variable displacement piston pump and the oil storage chamber 1 The oil passage between the ones is communicated, and the variable displacement piston pump has a pressurizing mechanism for pressing the motive oil in the oil reservoir 11 into the cylinder 10.

The pressurizing mechanism includes a movable handle 12 and a fixed handle 13. The movable handle 12 is hinged to the variable plunger pump, and the fixed handle 13 is fixed to the variable plunger pump, and the movable handle 12 is coupled to the high pressure plunger 2. As the movable handle 12 is reciprocated up and down, the high pressure plunger 2 reciprocates up and down so that the motive oil in the oil reservoir 3 can be pressed into the cylinder 10 through the oil inlet passage.

Specifically, in the low pressure state, that is, before the mold on the hydraulic wire crimping tool is not in contact with the cable and the terminal. As shown in Figure 1, the movable handle 12 drives the high voltage column The plug 2 moves up, and the low pressure plunger 3 moves up under the elastic force of the spring 4. In this process, the overflow mechanism is closed, the oil inlet check valve 2a is opened, and the oil discharge check valve 6a is opened, and the oil flows through. The oil hole 2 7 enters the lower chamber lb while the oil in the upper chamber la is discharged through the oil outlet hole 6. The oil drives the piston and the mold to move quickly.

As shown in FIG. 2, the movable handle 12 drives the high pressure plunger 2 to move downward, and the high pressure plunger 2 overcomes the spring force of the spring 4 and then presses the low pressure plunger 3 to move downwards. In this process, the overflow mechanism is closed and the oil inlet is closed. The valve 1a is opened, the oil discharge check valve 2a is opened, and the oil enters the upper cavity la through the oil inlet hole 5, and the oil in the lower cavity lb is discharged through the oil outlet hole 8-8. The oil drives the piston and the mold to move quickly.

In the high pressure state, that is to say the mould on the hydraulic line crimping tool is in the crimping. As shown in FIG. 3, the movable handle 12 drives the high pressure plunger 2 to move up, and the low pressure plunger 3 moves up under the elastic force of the spring 4, because the upper cavity la has a higher oil pressure, and the low pressure plunger 3 It cannot be in contact with the high pressure plunger 2 which is completely moved up. During this process, the relief valve is closed, the oil inlet check valve 2a is opened, and the oil enters the lower chamber l b through the oil inlet hole 7 and the oil in the upper chamber l a cannot be discharged. The mold stops moving.

As shown in FIG. 4, the movable handle 12 drives the high pressure plunger 2 to move downward, and the high pressure plunger 2 overcomes the spring force of the spring 4 and then presses the low pressure plunger 3 to move downwards. In this process, the overflow mechanism is opened and the oil discharge sheet is opened. To the valve 6a, the oil at the upper chamber la is discharged through the oil outlet hole 6. The male mold moves slowly. Obviously, the cable shearing tool with the variable displacement piston pump is easy to operate with low pumping efficiency and high pressure.

Claims

Claim

A variable displacement piston pump comprising a pump body (1) having a cavity inside, a low pressure plunger (3) and a high pressure plunger (2), said low pressure plunger (3) being disposed on said pump The body (1) is slidable up and down, and the low pressure plunger (3) divides the interior of the pump body (1) into two independent cavities: an upper cavity (la) and a lower cavity (lb). The lower chamber (lb) is provided with a spring (4) and the two ends of the spring (4) respectively act on the inner side of the low pressure plunger (3) and the pump body (1), and the high pressure plunger (2) passes through The pump body (1) has an inner end located in the upper cavity (1a) and an outer end extending out of the pump body (1), characterized in that the low pressure plunger (3) is provided An overflow mechanism, the pump body (1) has an oil inlet hole (5) and an oil outlet hole (6) communicating with the upper cavity (1), and the pump body (1) further has a lower portion The oil inlet hole (7) and the oil outlet hole (8) communicating with the cavity (lb), the oil inlet hole one (5), the oil inlet hole two (7), the oil outlet hole one (6) and Oil inlet two (8) is provided with oil inlet check valve one (5a), oil inlet one way Two (7a), an oil check valve (6a) and two oil-way valve (8a), and are consistent with the flow direction of the oil of the four-way valve.

2. The variable displacement piston pump according to claim 1, wherein the side of the low pressure plunger (3) has a convex rim (3a), and the spring (4) is sleeved on the low pressure plunger (3). ) and the end of the spring (4) abuts against the rim (3a).

The variable displacement piston pump according to claim 2, wherein the low pressure plunger (3) comprises a cylindrical body (3b), and the overflow mechanism is located in the body (3b) The plug (3c) and the overflow spring (3d), the inside of the body (3b) has a sealing portion which can be in contact with the plug (3c) to form a seal, and the two ends of the overflow spring (3d) respectively act on the body (3b) The plug (3c) has a tendency to abut against the seal at the plug (3c) and under the elastic force of the overflow spring (3d).

The variable displacement piston pump according to claim 3, characterized in that the spring force of the overflow spring (3d) is greater than the spring force of the intermediate spring (4) of the oil discharge check valve (6a).

The variable displacement piston pump according to claim 4, wherein the body (3b) is screwed with a pressure cap (9), and both ends of the overflow spring (3d) are divided It does not act on the pressure cap (9) and the plug (3c), and the pressure cap (9) has an oil hole (9a) for supplying oil.

The variable displacement piston pump according to claim 5, wherein the oil passage hole (9a) has a "T" shape, and the lower port of the oil hole (9a) communicates with the lower cavity (lb). The two upper ports of the oil hole (9a) communicate with the upper chamber (la).

The variable displacement piston pump according to claim 1 or 2 or 3 or 4 or 5 or 6, wherein said oil inlet check valve (5a) and oil inlet check valve 2 (7a) are both Located on the pump body (1) side, the oil discharge check valve one (6a) and the oil discharge check valve two (8a) are located on the other side of the pump body (1).

The variable displacement piston pump according to claim 7, wherein the oil inlet hole (5) and the oil outlet hole (6) are located at the top of the upper chamber (la).

The variable displacement piston pump according to claim 5, wherein the body (3b) port has a connecting seat (3b1) having a large aperture, and the end of the pressing cap (9) has an annular convex shape. There is a gap between the stop head (9b), the stop head (9b) and the body (3b) end connection seat (3b1), and the stop head (9b) abuts against the connection seat (3b1) and the above-mentioned oil passage hole ( The outlets of 9a) are located on either side of the stop (9b).

The variable displacement piston pump according to claim 1 or 2 or 3 or 4 or 5 or 6, wherein the pump body (1) has a concave spring seat (lbl) therein, and the spring (4) One end is located at the spring seat (lbl).