Variable displacement plunger pump with power-off active unloading neutral position returning function

Abstract

A variable displacement plunger pump with a power-off active unloading neutral position returning function is characterized in that a transmission shaft inputs rotating speed and torque, and a built-in oil supplementing pump generates control oil through inter-tooth oil suction and oil pressing. And oil is controlled to enter a closed cavity at one end of the shell and one end of the piston through distribution of the main control valve. Under the action of pressure of control oil, the piston moves in the direction that the closed containing cavity formed by the shell and the piston is enlarged, meanwhile, the piston is connected with the cradle through the sliding block, the cradle rotates at the corresponding angle accordingly, and therefore the displacement of the main pump changes correspondingly. By controlling the main control valve, the pressure oil liquid generated by the built-in oil supplementing pump can be controlled to generate certain displacement and rotation on the variable piston and the cradle, so that the displacement of the plunger pump is controlled.

Description

TECHNICAL FIELD

[0001] The utility model relates to plunger pump technical field, concretely relates to a variable displacement plunger pump with power-off active unloading back to the center position function. BACKGROUND

[0002] Most of the plunger pumps with power-off unloading back to the center position starting switch can only use the control valve with mechanical handle, and can only unload the control oil acting on the main control valve, so that the plunger pump rocker (swash plate) returns to the center position, realizing zero displacement output. But because the unloading oil way is not set in the main control oil way, it can only realize passive unloading, cannot completely cut off the control oil way to prevent the control oil from entering the variable cylinder, so it is easy to appear unloading, braking not timely or even unable to unloading and braking dangerous situation. SUMMARY

[0003] Therefore, the utility model provides a variable displacement plunger pump with power-off active unloading back to the center position function.

[0004] To realize above-mentioned purpose, the utility model provides the following technical scheme:

[0005] A variable displacement plunger pump with power-off active unloading back to the center position function, including the casing, the main control valve, oil supplement pump and brake valve are set up on the casing, the brake valve is set between the main control valve and oil supplement pump, the brake valve controls the oil way between the main control valve and oil supplement pump, the inner chamber is formed in the casing, the inner chamber has piston installation part, rocker installation part and plunger installation part, the main control valve is communicated with piston installation part, piston assembly, rocker and plunger assembly are set in piston installation part, rocker installation part and plunger installation part respectively, the transmission shaft that penetrates the inner chamber is set on the casing, the rocker is sleeved on the transmission shaft, the sliding piece is set between the rocker and piston assembly, the piston assembly drives the rocker to rotate through the sliding piece, one end of plunger assembly is connected with the rocker, the rocker rotates and drives plunger assembly to move in plunger installation part.

[0006] Preferably, the piston assembly includes a piston rod axially disposed in the piston installation part and a piston sleeved on the piston rod, the two ends of the piston rod are connected with the two opposite inner walls of the piston installation part respectively, a spring installation groove is formed between the piston and the piston rod, the spring installation groove includes a first groove part and a second groove part, a piston rod separation part is protruded at the center of the piston rod, a piston separation part is protruded on the inner wall of the piston corresponding to the piston rod separation part, the piston rod separation part and the piston separation part abut to block the first groove part and the second groove part, and springs are arranged in the first groove part and the second groove part.

[0007] Preferably, a sliding member mounting groove is formed on the outer wall of the piston, one end of the sliding member extends into the sliding member mounting groove and is connected with the piston, and the other end of the sliding member extends into the rocker mounting portion and is connected with the rocker in the rocker mounting portion.

[0008] Preferably, the rocker comprises a rocker body and a rotating body, the rotating body is sleeved on the transmission shaft, the rocker body covers one side of the rotating body close to the piston assembly, and the rocker body is in contact with the rotating body through the plunger assembly.

[0009] Preferably, the shell comprises a shell body and a rear cover, the inner cavity is formed in the shell body, one end of the rear cover extends into the inner cavity and seals the shell body, and the oil supplementing pump is arranged on the rear cover.

[0010] Preferably, a filter is further arranged on the shell, and the filter is in communication with the oil supplementing pump and the brake valve respectively.

[0011] The beneficial effects of the utility model lie in that the transmission shaft input rotation speed and torque, the built-in oil supplementing pump generates control oil liquid through oil suction and oil pressing between teeth. The control oil liquid is distributed through the main control valve and enters the closed cavity formed by the shell and one end of the piston. Under the pressure action of the control oil, the piston moves in the direction that the closed cavity formed by the shell and the piston increases, at the same time, the piston is connected with the rocker through the sliding block, and the rocker also generates corresponding angle rotation action, which makes the displacement of the main pump change correspondingly. Through controlling the main control valve, the pressure oil liquid generated by the built-in oil supplementing pump can cause certain displacement and rotation of the variable piston and the rocker, so as to control the displacement of the plunger pump. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor.

[0013] ATTACHMENT Figure 1 It is a structural schematic view of the utility model;

[0014] ATTACHMENT Figure 2 It is another angle structural schematic view of the utility model;

[0015] ATTACHMENT Figure 3 It is a sectional view of the utility model;

[0016] ATTACHMENT Figure 4 It is another direction sectional view of the utility model. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0018] The utility model will be further described below with reference to the drawings in the description.

[0019] The utility model provides the following technical scheme:

[0020] As shown in the accompanying Figures 1-4 The utility model discloses a variable displacement plunger pump with power-off active unloading and back to the middle position function, including the casing 1, the casing 1 is provided with main control valve 2, oil supplement pump 3 and brake valve 4, brake valve 4 is arranged between main control valve 2 and oil supplement pump 3, brake valve 4 controls the on-off of the oil circuit between main control valve 2 and oil supplement pump 3, the inner chamber 5 is formed in the casing 1, the inner chamber 5 has piston mounting portion 6, cradle mounting portion 7 and plunger mounting portion 8, main control valve 2 is communicated with piston mounting portion 6, piston mounting portion 6, cradle mounting portion 7 and plunger mounting portion 8 are provided with piston assembly 9, cradle 10 and plunger assembly 11 respectively, the transmission shaft 12 that passes through the inner chamber 5 is provided on the casing 1, the cradle 10 is sleeved on the transmission shaft 12, the sliding piece 13 is arranged between the cradle 10 and piston assembly 9, the piston assembly 9 drives cradle 10 to rotate through sliding piece 13, one end of plunger assembly 11 is connected with cradle 10, cradle 10 drives plunger assembly 11 to move in plunger mounting portion 8 during rotating. Specifically, in the design, transmission shaft 12 input speed and torque, built-in oil supplement pump 3 generates control oil by interdental oil absorption, oil pressure. Control oil is distributed through main control valve 2 and enters the airtight cavity of one end of casing 1 and piston 15. Under the action of control oil pressure, piston 15 moves to the direction that the airtight cavity formed by casing 1 and piston 15 increases, at the same time, piston 15 is connected with cradle 10 through sliding block, and cradle 10 also generates corresponding angle rotating action, which makes the displacement of main pump change. By controlling main control valve 2, the pressure oil generated by built-in oil supplement pump 3 can control the displacement of variable piston 15 and cradle 10, so as to control the displacement of plunger pump.

[0021] Further, the piston assembly 9 comprises a piston rod 14 axially arranged in the piston mounting portion 6 and a piston 15 sleeved on the piston rod 14, two ends of the piston rod 14 are connected with two opposite inner walls of the piston mounting portion 6 respectively, a spring mounting groove 16 is formed between the piston 15 and the piston rod 14, the spring mounting groove 16 comprises a first groove portion 17 and a second groove portion 18, a piston rod partition portion 19 is protruded in the center of the piston rod 14, an inner wall of the piston 15 is protruded to form a piston partition portion 20 corresponding to the piston rod partition portion 19, the piston rod partition portion 19 and the piston partition portion 20 are opposite to each other to separate the first groove portion 17 and the second groove portion 18, and a spring 21 is arranged in each of the first groove portion 17 and the second groove portion 18. In addition, the piston rod partition portion 19 ensures the fixed position of the spring 21 on the piston rod 14, prevents the spring 21 from being displaced during the work process, and ensures the reliability of the whole system. In this embodiment, the material of the piston rod 14 is selected to be high-strength alloy steel to withstand high pressure and wear during the work process.

[0022] Further, a slider mounting groove 22 is formed in the outer wall of the piston 15, one end of the slider 13 is inserted into the slider mounting groove 22 to be connected with the piston 15, and the other end of the slider 13 is inserted into the cradle mounting portion 7 to be connected with the cradle 10 in the cradle mounting portion 7. Specifically, in this embodiment, the piston 15 is connected with the cradle 10 through the slider 13, so that the piston 15 can reciprocate on the piston rod 14, and the use of the slider 13 increases the flexibility and adaptability of the piston assembly 9.

[0023] Further, the cradle 10 comprises a cradle body 23 and a rotary body 24, the rotary body 24 is sleeved on the transmission shaft 12, the cradle body 23 is arranged on the side of the rotary body 24 close to the piston assembly 9, and the cradle body 23 and the rotary body 24 are in contact with each other through the plunger assembly 11. Specifically, in this embodiment, the plunger assembly 11 comprises a plunger 25 and a sliding shoe 32, one end of the plunger 25 is connected with the rotary body 24, and the other end of the plunger 25 is connected with the sliding shoe 32. The sliding shoe 32 is tightly matched with the inner wall of the cradle body 23, so as to ensure the stability and sealing performance of the plunger assembly 11 during the work process.

[0024] Further, the shell 1 comprises a shell body 27 and a rear cover 28, the inner cavity 5 is formed in the shell body 27, the rear cover 28 is inserted into the inner cavity 5 to seal the shell body 27, and the oil supplement pump 3 is arranged on the rear cover 28.

[0025] Further, a filter 29 is arranged on the shell 1, and the filter 29 is in communication with the oil supplement pump 3 and the brake valve 4 respectively.

[0026] The plunger pump working state: in the process of the main control oil from the oil supplement pump 3 to the main control valve 2, the brake valve 4 arranged on the rear cover 28 needs to be passed. The brake valve 4 is arranged in the main control oil path, and the main control oil path is connected only after the brake valve 4 is electrified. After the main control oil is pressed out from the oil supplement pump 3, it passes through the filter 29 and then passes through the brake valve 4 to the main control valve 2. The brake valve 4 is internally provided with a detachable damping screw plug (not shown in the figure), and different diameter damping screw plugs can be replaced to adjust the action speed of the main control oil on the variable mechanism of the plunger pump and the response speed of the system signal, thereby reducing the adverse impact on the equipment and system. When the main control valve 2 generates action from the external mechanical position signal or electrical signal, the main control oil can be distributed into the corresponding closed cavity (the closed cavity is formed between the shell 1, the end cover and the piston 15) to act on the corresponding closed cavity. Under the action of the main control oil pressure, the piston 15 moves in the piston 15 hole of the shell 1, thereby pushing the slider to rotate the swing frame 10, so that the swing frame 10 is deflected by a corresponding angle to achieve the purpose of controlling the displacement of the plunger pump. The working oil of the plunger pump is sucked from the oil port 30 or the low-pressure side, the mechanical energy is converted into pressure energy through the rotary body 24, and the working oil is pressed out from the working oil port 31 or the high-pressure side to realize the output of working oil with a certain flow and pressure.

[0027] The plunger pump unloading and braking state: when the plunger pump works under load, working fluid with a certain pressure and flow can be output. When the hydraulic equipment or system encounters a specific working condition or special situation and needs to be braked, the equipment or system only needs to give a power-off signal to the brake valve 4. After power-off, the electromagnetic iron in the brake valve 4 reverses, the main control oil path through the brake valve 4 is cut off, and the one-way valve (not shown in the figure) in the brake valve 4 is opened under the action of the hydraulic pressure on both sides (the closed cavity side of the shell 1 and the oil suction oil channel side of the built-in oil supplement pump 3) to connect the closed cavity of the shell 1 and the oil suction oil channel of the built-in oil supplement pump 3 in the rear cover 28, thereby depressurizing the closed cavity of the shell 1. The spring 21 is arranged in the piston 15, and the closed cavity of the shell 1 is depressurized. During the depressurization process, the piston 15 is pushed to move to the side of the depressurized closed cavity due to the action of the spring 21 in the closed cavity. At this time, the internal volume of the depressurized closed cavity on one side is reduced, and the internal volume of the corresponding closed cavity on the other side is increased. When the piston 15 moves, the slider moves, and the swing frame 10 also rotates by a corresponding angle to make the plane where the swing frame 10 and the sliding shoe 32 are in close contact finally perpendicular to the central axis of the transmission shaft 12. This makes the displacement of the plunger pump change correspondingly, and the output flow through the rotary body 24 is reduced to 0 L / min, thereby achieving the effect of braking the system or equipment and realizing the function of actively cutting off the control oil path to unload the plunger pump to the neutral position.

[0028] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A variable displacement piston pump with power-off active unloading and centering function, characterized by: The application relates to a brake valve, which comprises a shell, a main control valve, an oil supplement pump and a brake valve, the brake valve is arranged between the main control valve and the oil supplement pump, the brake valve controls the opening and closing of an oil passage between the main control valve and the oil supplement pump, an inner cavity is formed in the shell, the inner cavity has a piston mounting portion, a rocker mounting portion and a plunger mounting portion, the main control valve is communicated with the piston mounting portion, a piston assembly, a rocker and a plunger assembly are arranged in the piston mounting portion, the rocker mounting portion and the plunger mounting portion respectively, a transmission shaft penetrating through the inner cavity is arranged on the shell, the rocker is sleeved on the transmission shaft, a sliding piece is arranged between the rocker and the piston assembly, the piston assembly drives the rocker to rotate through the sliding piece, one end of the plunger assembly is connected with the rocker, and the rocker drives the plunger assembly to move in the plunger mounting portion during rotation.

2. The variable displacement piston pump with de-energized active unloading return center function of claim 1, wherein: The piston assembly comprises a piston rod arranged axially in the piston mounting portion and a piston sleeved on the piston rod, both ends of the piston rod are connected with two opposite inner walls of the piston mounting portion respectively, a spring mounting groove is formed between the piston and the piston rod, the spring mounting groove comprises a first groove portion and a second groove portion, a piston rod separation portion is formed on the center of the piston rod in a protruding mode, an inner wall of the piston protrudes to form a piston separation portion corresponding to the piston rod separation portion, the piston rod separation portion and the piston separation portion are in opposite connection to block the first groove portion and the second groove portion, and springs are arranged in the first groove portion and the second groove portion.

3. The variable displacement piston pump with de-energized active unloading return center function of claim 2, wherein: A sliding piece mounting groove is formed on an outer wall of the piston, one end of the sliding piece is connected with the piston by extending into the sliding piece mounting groove, and the other end of the sliding piece is connected with the rocker in the rocker mounting portion.

4. The variable displacement piston pump with de-energized active unloading return center function of claim 1, wherein: The rocker comprises a rocker body and a rotary body, the rotary body is sleeved on the transmission shaft, the rocker body is covered on one side of the rotary body close to the piston assembly, and the rocker body and the rotary body are in contact through the plunger assembly.

5. The variable displacement piston pump with de-energized active unloading return center function of claim 1, wherein: The shell comprises a shell body and a rear cover, the inner cavity is formed in the shell body, one end of the rear cover extends into the inner cavity to seal the shell body, and the oil supplement pump is arranged on the rear cover.

6. The variable displacement piston pump with de-energized active unloading return center function of claim 1, wherein: A filter is further arranged on the shell, and the filter is communicated with the oil supplement pump and the brake valve respectively.

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