KR20230090128A - Variable hydraulic pump - Google Patents

Abstract

In accordance with the present invention, disclosed is a variable hydraulic pump. In accordance with the present invention, disclosed is a variable hydraulic pump. More specifically, the variable hydraulic pump includes: a motor; a driving shaft connected to a shaft of the motor to be rotated; a housing part housing the driving shaft; a cam part coupled to the driving shaft to be rotated; and at least one plunger part connected to the cam part to perform pumping, wherein the cam part is coupled to the driving shaft to be inclined by a predetermined eccentricity angle, and, when a plunger guide part having a ring shape and equipped with the plunger part is reciprocated in a longitudinal direction of the driving shaft in the housing part, a fluid discharge amount is varied in proportion to a stroke distance varying as a piston of the plunger part is moved in contact with a slope of the cam part. Therefore, the present invention is capable of considerably improving productivity.

Description

Variable hydraulic pump {Variable hydraulic pump}

The present invention relates to a hydraulic pump, and more particularly, to a variable hydraulic pump capable of performing pumping by appropriately controlling the pressure and flow rate of the pump according to the output force required for work.

A hydraulic pump is a device that converts mechanical energy supplied from the outside into pressure energy of hydraulic system hydraulic oil. of pumps are being developed.

And, according to the required power, a high pressure pump used where high pressure is required and a low pressure pump used where low pressure is required are provided separately.

However, in the case of work requiring hydraulic pressure, low pressure is generally required initially, and in most cases, high pressure is required during actual work.

At this time, a low pressure and high pressure combined pump is often used to measure a large force as the speed slows down at a high pressure while working at a high speed at a low pressure.

1 is a cross-sectional view showing a conventional high-pressure hydraulic pump.

Specifically, "a motor that provides rotational power and is mounted outside the oil tank in which oil is stored; a housing 100 provided inside the oil tank and accommodating the driving shaft 20 of the motor; mounted on the housing, A low-pressure pump (200) that sucks in and compresses the oil inside the oil tank by rotation of the driving shaft; A plurality of cam members are installed radially around the driving shaft on the outer circumferential surface of the housing and are formed on the driving shaft. A high-pressure pump 300 that secondarily compresses the oil supplied from the low-pressure pump by a piston reciprocating in conjunction with ( ); Shields the open upper surface of the housing and is formed in a circular shape to connect the plurality of high-pressure pump outlets and A discharge block 400 formed with a discharge passage 410 communicated with all of them and a discharge port 420 communicating with the discharge passage to discharge hydraulic oil to the outside; provided on one side of the housing, and the pressure of the discharge passage is set An unloading valve unit (600) that drains a portion of the oil primarily compressed by the low pressure pump when the pressure is higher than the pressure; is provided inside the housing and connects the discharge passage and the unloading valve unit to the unloading valve unit (600) A high pressure oil passage 640 providing pressure for the operation of the housing; A first low pressure oil passage 110 formed inside the housing and supplying the hydraulic fluid discharged from the low pressure pump to the discharge port; Inside the housing a second low pressure oil passage 120 formed inside the housing and supplying the hydraulic oil discharged from the low pressure pump to the high pressure pump; formed inside the housing and supplying the hydraulic oil discharged from the low pressure pump to the unloading valve unit; The unloading valve unit includes a third low pressure passage 130, and the unloading valve unit includes an unloading valve passage 630 formed inside the housing so that the unloading piston can reciprocate; the unloading valve passage An unloading check valve 610 that opens and closes and supports one end of the unloading piston; The other end of the unloading piston receives and is connected to the high-pressure oil passage to move the unloading piston according to the pressure of the working oil. A high-pressure hydraulic pump configured to include an unloading chamber 660 is disclosed.

These conventional hydraulic pumps are generally low-power (power), but only use low-pressure pumps for high-speed operation, and operate and use high-pressure pumps with low operating speeds when high output (power) is required.

However, in the case of a high-pressure pump, even when an output smaller than the maximum output is required, the operation speed is still inevitably slow because the maximum output force must be used.

For example, the graph shown in FIG. 12 is a correlation graph between pressure and discharge flow rate of a conventional variable hydraulic pump.

First, the output power is F = P×A (where F is the output power, P is the pressure, and A is the cross-sectional area of the hydraulic system), and the horsepower of the hydraulic motor is HP = PQ / 450η (where HP is horsepower, Q is the discharge The flow rate, 450η is a constant), and the flow rate is V = Q/A (where V is the flow rate). Assuming that 450η is 500, the pressure is 0 to 100 kg/cm2 when the low pressure pump is operating. Since the flow rate becomes 10L/m, work of HP = 2 horsepower is performed.

In addition, since the speed and the flow rate are proportional, the speed is also maximized at the maximum flow rate, so that fast work can be performed.

If, when a task requiring maximum output is performed, the low-pressure pump is stopped and the high-pressure pump operates immediately, so even if the pressure changes from 100 to 1000 kg/cm2, the flow rate discontinuously and rapidly decreases to a constant 1 L/m. Thus, work of up to Hp = 2 horsepower can be performed.

At this time, when the pressure is maximum (1000 kg / cm 2), the output force is maximized and 100% of work is performed, but since the pressure and flow rate are inversely proportional, the flow rate is minimized and the speed is also minimized, so the work speed is very slow.

However, when performing work that does not require maximum output force, for example, when only 20% of the force is required, even if the pressure is lowered to 200 kg/cm2, the flow rate remains at 1 L/m, so the work speed is still become slow

Since it is difficult to have all hydraulic pumps with different output powers depending on the power required in the actual field, a hydraulic pump that can supply various output powers with one hydraulic pump and at the same time provide the maximum working speed for each output power is required. do.

Korean Registered Patent No. 10-1389690 (2014.4.22.) "Hydraulic pump for high pressure" Republic of Korea Patent No. 10-1196946 (2012.10.26.) "High pressure hydraulic pump" Republic of Korea Patent Publication 10-2021-0057597 (2021.5.21.) "Swash plate pump"

Accordingly, the present invention was developed to solve the above-mentioned conventional problems, and an object of the present invention is to automatically control the pressure and flow rate according to the output force required for work, so that it can always work with maximum horsepower At the same time, it is to provide a variable hydraulic pump that can perform work faster.

In order to achieve the above object, a variable hydraulic pump according to the present invention includes a motor, a drive shaft interlocked with a shaft of the motor and driven to rotate, a housing portion accommodating the drive shaft, and a cam portion coupled to the drive shaft and rotating; , In the hydraulic pump including one or more plunger parts connected to the cam part to perform pumping, the cam part is inclinedly coupled to the drive shaft by a predetermined eccentric angle, forms a ring shape, and a plunger guide part to which the plunger part is mounted is attached to the housing. When reciprocating along the longitudinal direction of the drive shaft within the unit, the discharge amount of the fluid may be varied in proportion to the changed stroke distance while the piston of the plunger unit moves while in contact with the inclined surface of the cam unit.

Here, the cam part is provided between a camshaft inclinedly coupled to the drive shaft with a predetermined eccentric angle, a camring having a cylindrical shape and surrounding the outer circumferential surface of the camshaft and contacting the piston end of the plunger, and between the camring and the camshaft. It can be made including a roller bearing to be.

And the plunger part, a cylinder body having a cylinder hole formed therein, one end formed with a suction hole through which the fluid is sucked while communicating with the cylinder hole, and a discharge hole through which the fluid is discharged while communicating with the cylinder hole on a side surface thereof, and inserted into the cylinder hole It may include a piston spring, a piston inserted into the cylinder hole to reciprocate and elastically supported by the piston spring, a suction check valve for opening and closing the suction hole, and a discharge check valve for opening and closing the discharge hole. there is.

In addition, the plunger guide part is formed in a circular ring shape so as to surround the driving shaft and the cam part in the center, moves reciprocally in the housing part, and is provided between a guide ring coupled to the plunger part on the front side and an end portion of the guide ring and the housing. and a guide spring for elastically supporting the guide ring, and a hydraulic passage for guiding the fluid discharged from the plunger unit to an outlet formed on an outer circumferential surface of the housing unit may be formed in the guide ring.

At this time, a stepped first step is formed on one side of the outer circumferential surface of the guide ring, and a stepped second step is formed on the other side of the inner circumferential surface of the housing part, and the variable clearance formed by the first step and the second step is the hydraulic pressure It communicates with the furnace and the outlet, and the guide ring can move forward while the fluid flowing in through the hydraulic passage fills the variable clearance.

A decompression means may be further provided between the outlet and the rear surface of the guide ring to reduce the pressure of the fluid discharged from the outlet and supply the fluid to the guide ring to advance.

The decompression means includes a decompression cylinder connected to the outlet and reducing pressure, and a decompression nozzle inserted into the rear surface of the guide ring and connected to the outlet of the decompression cylinder to supply decompressed fluid to advance the guide ring. A decompression booster may be used. At this time, a pressure reducing valve may be used instead of the pressure reducing cylinder.

According to the present invention described above, there are the following effects.

First, as the cam having an eccentric angle rotates, the plunger part rises and falls, and pumping is performed. As the plunger part moves horizontally while in contact with the inclined surface of the cam part, the stroke distance between the top dead center and the bottom dead center of the plunger part changes linearly. And, the discharge amount of the fluid can be continuously varied in proportion to the stroke distance.

Second, when the high-pressure pump operates, the product of pressure and flow rate is controlled to be constant, so when performing work requiring less power than the maximum output power, the flow rate increases instead of the pressure decreases, increasing the operating speed by 2 to 5 times compared to the previous one. can This has the epoch-making advantage of greatly improving productivity.

Third, when power of various sizes is required, in the past, a plurality of pumps suitable for the capacity were required. this is very high

1 is a cross-sectional view showing a conventional high-pressure hydraulic pump
2 is a cross-sectional view showing a variable hydraulic pump according to an embodiment of the present invention
Figure 3 is a detailed view showing the structure of the main part of the present invention shown in Figure 2
Figure 4 is an exploded view of the main part shown in Figure 3
Figure 5 is a cross-sectional view of the main part shown in Figure 2
6 is an exploded cross-sectional view of the plunger portion and the plunger guide portion shown in FIG. 4;
Figure 7 is an enlarged cross-sectional view of the contact surface of the housing portion and the guide ring of the present invention
8 is a cross-sectional view showing a variable hydraulic pump according to another embodiment of the present invention
9 is an operating state diagram of the present invention
10 is an operational conceptual diagram showing a state in which the cam part rotates 180 ° and the plunger part moves according to the present invention.

Hereinafter, an embodiment according to the present invention will be described in more detail with reference to the accompanying drawings.

For reference, the description with reference to the drawings is for easier understanding of the present invention, and the scope of the present invention is not limited thereto. And, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

2 is a cross-sectional view showing a variable hydraulic pump according to an embodiment of the present invention.

The present invention may be largely composed of a motor 100, a drive shaft 120, a housing part 200, a cam part 300, a plunger part 400, and a plunger guide part 500.

First, the motor 100, the driving shaft 120, and the housing portion 200 will be described.

The motor 100 is coupled to one side of the housing part 200, and the driving shaft 120 is axially coupled to the motor shaft 110 to be rotationally driven.

At this time, the driving shaft 120 rotates while being accommodated in the housing part 200 .

And, the housing part 200 may be composed of a main body 210 and a cover 220 covering the main body 210 so as to be opened and closed.

In addition, one or more outlets 211 through which the pumped fluid can be discharged are formed on the side of the body 210. The outlet 211 may be formed in two or four directions.

A low pressure pump 700 is attached to the lower end of the housing part 200 to supply fluid (oil) at a low pressure to the inside of the housing part 200 to work as a low pressure pump or to supply oil.

Next, the cam portion will be described with reference to FIGS. 3 to 5 together. 3 is a detailed view showing the structure of the main part of the present invention shown in FIG. 2, FIG. 4 is an exploded view of the main part shown in FIG. 3, and FIG. 5 shows a cross-sectional view of the main part shown in FIG.

The cam part 300 is obliquely coupled to the driving shaft 120 to operate the plunger part 400 to pump, but is eccentric to induce it to operate with a different stroke depending on the position of the plunger part 400. wet.

The cam part 300 may be implemented with a camshaft 310, a cam ring 320, and a roller bearing 330.

The camshaft 310 is in the shape of a circular shaft having a circular cross-section, and one end is obliquely coupled to the drive shaft 120 at a predetermined eccentric angle E, and the other end is inside the cover 220 of the housing part 200. It is rotatably coupled to the idle shaft 340 coupled to the provided bearing (B).

Specifically, the driving shaft 120 has a larger diameter than the camshaft 310 and an inclined surface 121 is formed at an end thereof. And one end of the camshaft 310 is coupled to the inclined surface 121 .

In addition, a wedge-shaped inclined block 341 may be coupled to an end of the idle shaft 340 so that the camshaft 310 is inclinedly coupled.

Here, it is important that the axes of the drive shaft 120 and the idle shaft 340 coincide.

Therefore, an angle formed by a straight line connecting the axial centers of the drive shaft 120 and the idle shaft 340 and a straight line passing through the axial center of the camshaft 310 is an eccentric angle E, and the eccentric angle E is approximately 5 to 5 It can be as much as 10°. In the present invention, an embodiment in which the eccentric angle (E) is designed to be 6.5 ° is shown. (See Fig. 10)

A cylindrical cam ring 320 is provided to surround the outer circumferential surface of the camshaft 310 .

The cam ring 320 is configured to directly contact the piston 420 of the plunger part 400, and preferably has a smooth surface to facilitate sliding.

A roller bearing 330 is inserted between the cam ring 320 and the camshaft 310 . That is, the inner ring of the roller bearing 330 is coupled to the camshaft 310 and the outer ring is coupled to the cam ring 320 .

Therefore, even if the camshaft 310 rotates by the roller bearing 330, the cam ring 320 remains in an idle state and does not rotate.

What is important is that the eccentricity radius (R) becomes smaller toward the front of the cam part 300 because of the eccentricity angle (E).

Next, the plunger portion will be described with reference to FIG. 6 . FIG. 6 is an exploded perspective view of the plunger part and the plunger guide part shown in FIG. 4 .

The plunger part 400 pumps the fluid inside the housing part 200 in a state of being in contact with the cam ring 320 of the cam part 300 and discharges it through the outlet 211 of the housing part 200.

That is, one or more plunger parts 400 may be provided to correspond to the number of outlets 211 . When the outlet 211 is installed at 12, 3, 6, and 9 o'clock directions of the main body 210, a total of four plunger parts 400, one each, may be provided at the same position. However, it is not limited thereto, and 3 to 8 plunger units may be provided.

Specifically, the plunger part 400 may be implemented as a cylinder body 410, a piston 420, a piston spring 430, a suction check valve 440, and a discharge check valve 450.

The cylinder body 410 provides a space where fluid is sucked and discharged, and a cylinder hole 411 having a certain depth is formed in the center and a suction hole 412 through which fluid can be sucked is formed at one end. and communicates with the cylinder hole 411.

A discharge hole 413 through which fluid is discharged is formed on the side surface of the cylinder body 410 and communicates with the cylinder hole 411 .

A piston spring 430 in the form of a coil spring is inserted into the cylinder hole 411 and one end is supported by the bottom of the cylinder hole 411 .

In addition, a piston 420 is inserted into the cylinder hole 411 and can slide reciprocally, and the piston 420 is elastically supported by the piston spring 430 . At this time, a spring hole 421 is formed in the piston 420 so that the piston spring 430 can be elastically supported while being inserted into the spring hole 421 .

In addition, a hemispherical contact hole 422 is formed at an outer end of the piston 420 to make point contact with the outer circumferential surface of the cam ring 320 and interlock with the eccentric rotation of the cam part 300 .

A suction check valve 440 may be installed in the suction hole 412 and a discharge check valve 450 may be installed in the discharge hole 413 .

The suction check valve 440 may include a suction ball 441 and a suction spring 442, and the discharge check valve 450 may include a discharge ball 451 and a discharge spring 452.

In other words, the suction check valve 440 operates so that it is opened only when the suction spring 442 and the suction ball 441 are installed sequentially from the inside of the suction hole 412 and the fluid is sucked.

In addition, the discharge check valve 450 is provided so that the discharge ball 451 blocks the discharge hole 413, and the discharge spring 452 installed in the plunger guide part 500 is connected to the discharge ball 451. is elastically supported to open only when fluid is discharged through the discharge hole 413.

Therefore, when the cam part 300 rotates eccentrically, the piston 420 in contact with the cam ring 320 moves up and down, and the fluid is sucked into the cylinder hole 411 through the suction hole 412. The process of being discharged through the discharge hole 413 is repeated.

Next, the plunger guide part 500 will be described.

The plunger guide part 500 may reciprocate the plunger part 400 horizontally.

Specifically, the plunger guide part 500 may include a guide ring 510 and a guide spring 520.

The guide ring 510 is formed in a donut or circular ring shape, is accommodated inside the housing part 200, and can move along the longitudinal direction while its outer circumferential surface is in close contact with the inner circumferential surface of the housing part 200. At this time, the drive shaft 120 and the cam portion 300 pass through the center of the guide ring 510 .

And the plunger part 400 is coupled to the front surface of the guide ring 510 . At this time, the discharge hole 413 of the plunger part 400 is coupled to face the front surface of the guide ring 510 .

In addition, a hydraulic passage 511 communicating the front surface and the outer circumferential surface of the guide ring 510 is formed in a 'B' shape, and an inlet of the hydraulic passage 511 communicates with the discharge hole 413. At this time, the discharge spring 452 may be inserted into the inlet of the hydraulic passage 511 to elastically support the discharge ball 451 blocking the discharge hole 413 .

The fluid passing through the hydraulic path 511 may be guided to the outlet 211 and discharged.

Preferably, the number of hydraulic passages 511 corresponding to the number of the plunger parts 400 is formed, and as described above, it may be formed at 12, 3, 6, and 9 o'clock directions, but is not limited thereto.

In addition, a spring groove 512 into which the guide spring 520 can be inserted is formed between the hydraulic passages 511 .

Meanwhile, one end of the guide spring 520 is inserted into the spring groove 512 and the other end is inserted into the cover 220 of the housing part 200 . The guide spring 520 may use a compression coil spring.

Accordingly, the guide ring 510 may move forward and then move backward and return by the elastic force of the guide spring 520 .

In other words, the guide ring 510 is moved backward by the guide spring 520 and is located close to the motor side, and then the internal pressure increases and the guide ring 510 moves forward, thereby causing the piston ( 420) moves to the front of the cam part 300.

At this time, as described above, since the eccentric radius R decreases toward the front of the cam part 300, the stroke distance of the piston 420 in contact with the cam part 300 also decreases, and thus the pumping flow rate (hereinafter referred to as 'discharge flow rate'). ') becomes smaller.

In the present invention, a variable clearance sealed between the inner circumferential surface of the housing part 200 and the outer circumferential surface of the guide ring 510 so that the guide ring 510 can move forward by the hydraulic pressure discharged through the hydraulic passage 511 ( C) is preferably formed.

Figure 7 shows an enlarged cross-sectional view of the contact surface of the housing portion and the guide ring of the present invention.

In the present invention, a stepped first step 513 is formed on one side of the outer circumferential surface of the guide ring 510, and a stepped second step 212 is formed on the other side of the inner circumferential surface of the housing part 200. At this time, the height of the first step 513 and the second step 212 may be formed to be the same.

In other words, the outer diameter of the guide ring 510 is formed differently based on the first step 513, so that the outer diameter is composed of a relatively larger outer diameter portion and a smaller smaller outer diameter portion, and the second step 212 Based on , the inner diameter of the housing portion is formed differently from each other, and is composed of a relatively large inner diameter portion and a smaller inner diameter portion.

In addition, the outer diameter of the guide ring 510 and the inner diameter of the housing 200 come into close contact with each other, and the small outer diameter of the guide ring 510 and the small inner diameter of the housing 200 come into close contact with each other, so that the first stepped step A variable gap (C) is formed between the 513 and the second step 212.

The volume of the variable clearance C may increase or decrease according to the forward and backward movement of the guide ring 510 .

Also, the variable clearance C may communicate with the hydraulic passage 511 on one side and communicate with the outlet 211 on the other side.

Therefore, if the fluid flows into and fills the variable clearance C through the hydraulic passage 511, and the pressure of the outlet 211 communicating with the outside is high, the guide ring 510 is affected by the pressure of the filled fluid. ) is pushed forward.

Hereinafter, another embodiment of the present invention will be described with reference to FIG. 8 . 8 is a cross-sectional view showing another embodiment of the present invention.

Another embodiment of the present invention may implement a structure in which the pressure reducing means 600 is further included in the above structure.

When the hydraulic pressure in the variable clearance (C) is too high and the forward speed of the guide ring 510 is too high, the pressure reducing unit 600 reduces the pressure in the variable clearance (C) to advance the guide ring 510. By lowering , it can be controlled to advance smoothly.

The decompression unit 600 may use a decompression booster 610 .

However, in this case, the structure has no variable clearance (C). That is, without the first step 513 and the second step 212, the outer circumferential surface of the guide ring 510 completely adheres to the inner circumferential surface of the housing 200 and slides.

Referring to FIG. 8, the pressure reducing booster 610 is provided between the outlet 211 and the guide ring 510 to decompress a portion of the fluid discharged from the outlet 211, and then the guide ring ( 510) to push the guide ring 510 forward slowly.

Specifically, the decompression booster 610 may be implemented by including a decompression cylinder 611 and a decompression nozzle 612 .

In the pressure reducing cylinder 611, the pressure reducing piston 611a advances by the high pressure of the fluid discharged from the outlet 211, but the pressure decreases by making the cross-sectional area of the pressure reducing piston 611a different.

That is, a small diameter portion 611b and a large diameter portion 611c are formed inside the body of the pressure reducing cylinder 611, and one side of the pressure reducing piston 611a reciprocates within the small diameter portion 611b, and the other side It is provided to reciprocate within the large-diameter portion 611c.

Therefore, the fluid discharged from the outlet 211 flows into the small diameter portion 611b and pushes the pressure reducing piston 611a to advance, and the fluid in the large diameter portion 611c is also pushed and discharged to form the pressure reducing cylinder 611 ) and the pressure reducing nozzle 612 are supplied to the pressure reducing nozzle 612 through the pressure reducing passage 613 connecting the pressure reducing nozzle 612.

At this time, while the inner diameter of the body of the pressure reducing cylinder 611 increases, the pressure decreases.

That is, in the relationship of F (force) = P (pressure) × A (cross-sectional area of large diameter or small diameter), when F is constant, the pressure decreases as the cross-sectional area increases.

And, the pressure reducing nozzle 612 is inserted into the pressure reducing hole 514 formed on the rear surface of the guide ring 510 to inject and supply fluid into the pressure reducing hole 514, thereby pushing the guide ring 510 forward. do.

The same function can be implemented by attaching a pressure reducing valve (not shown) instead of the pressure reducing cylinder 611. That is, the inlet of the pressure reducing valve and the outlet 211 are connected, and the outlet of the pressure reducing valve and the pressure reducing nozzle 612 are connected to perform the same function. Since the pressure reducing valve is well known, a detailed description thereof will be omitted.

Hereinafter, the operating process of the present invention will be described in detail with reference to FIGS. 9, 10, and 11 together. 9 shows an operating state diagram of the present invention, FIG. 10 shows an operating conceptual diagram showing a state in which the cam part of the present invention rotates 180 ° and the plunger part moves, and FIG. 11 is a graph showing the correlation between pressure and flow rate of a hydraulic pump. am. Here, FIG. 11 (a) shows a conventional hydraulic pump, and FIG. 11 (b) shows the present invention.

First, the above-described FIG. 3 shows a state in which the low pressure pump operates. That is, when a job requiring only the minimum output power is operated, only the low pressure pump can be operated and the job can be performed at a high speed.

For example, referring to the bar shown in FIG. 11(b), when the low-pressure pump is operated, the pressure is 100 kg/cm 2 or less, and the flow rate is 10 L/m, which is the maximum. At this time, since the speed is proportional to the flow rate, the operating speed is also maximized.

It can be used where high operating speed is required without the need for great force in normal hydraulic systems. For example, in the case of lifting a heavy object with a hydraulic cylinder, it can be used when the hydraulic cylinder is installed and the rod is rapidly advanced to reach the weight.

For reference, when only the low pressure pump operates, the plunger part 400 is in a state closest to the driving shaft 120 side.

Next, when a job requiring a large force is performed, the plunger part 400 moves from left to right (direction away from the drive shaft) as shown in FIGS. 9 and 10 .

For example, in FIG. 11 (b), when the pressure to produce the maximum output force (100%) of the present invention is 1000 kg/cm2, looking at the case where only about 20% of the actual output force is required, the pressure required in the graph is 200 kg/cm 2 , and the flow rate at this time is 5 L/m.

To this end, as shown in FIG. 10 , the piston 420 of the plunger part 400 is located at the top dead center. In this state, when the cam part 300 rotates 180°, the piston 420 is located at the bottom dead center.

At this time, the discharged flow rate is discharged by the stroke distance S1 corresponding to the interval between the top dead center and the bottom dead center.

That is, the amount discharged at one time from one plunger unit 400 corresponds to A (cross-sectional area of the cylinder hole) × S1 (stroke distance), and by one discharge flow rate (Q1) = A × V1 (flow rate) is derived

For reference, if there are four plunger parts 400, the total flow rate Q1 can be calculated by multiplying by four. Here, the flow rate may be obtained by the rotational speed (RPM) of the cam part 300.

However, since HP (horsepower) of the motor 100 is calculated from = P1 (pressure) × Q1/450η, when the horsepower is constant, the pressure and the flow rate have a relationship inversely proportional to each other.

In summary, in the case of a job requiring only about 20% of the output power, the pressure can be the smallest while the discharge flow rate and speed can be maximized.

That is, comparing (a) and (b) in FIG. 11, in the prior art, only 1 L/m was discharged when 20% of the output power was required, but in the case of the present invention, 5 L/m is discharged, so the discharge is 5 times greater. It can supply flow and at the same time operate five times faster.

The discharged fluid is discharged through the outlet 211 to operate the hydraulic device faster than in the prior art.

In addition, since the flow rate is small in the prior art, the amount of work (horsepower) that can be performed is inevitably reduced, but in the case of the present invention, since the maximum horsepower is exerted, the motor is operated at 100% to achieve maximum efficiency. .

Next, with reference to the bar shown in FIG. 9A, an operation requiring about 50% of the maximum output force will be described.

For example, looking at the case in which only about 50% of the output force is required in FIG. 11, the required pressure in the graph is 500 kg/cm 2 , and the flow rate at this time is 2 L/m.

If a force of about 50% of the maximum output force is required, a large pressure is applied to the outlet 211, so that the fluid cannot be discharged through the outlet 211, and as a result, the pressure inside the variable clearance (C) is increased. It increases.

Therefore, as described above, when the pressure in the variable clearance (C) increases, the guide ring 510 moves forward. Alternatively, when there is no variable clearance (C), the fluid depressurized through the pressure reducing means 600 pushes the guide ring 510 from the rear side to gradually advance.

However, when the plunger part 400 reaches the center of the cam part 300 as the guide ring 510 moves forward, the top dead center and bottom dead center of the piston 420 of the plunger part 400 are reached at this position. The interval of is S2 and has a stroke distance smaller than S1, so the discharge flow rate also decreases.

That is, the amount discharged at one time from the plunger unit 400 corresponds to A (cross-sectional area of the cylinder hole) × S2 (stroke distance), and is derived by one-time discharge flow rate (Q2) = A × V2 (flow rate) do.

Also, the flow rate can be obtained by the rotational speed (RPM) of the cam part 300.

However, since it is calculated from HP (horsepower) = P2 (pressure) × Q2 / 450η of the motor 100, when the horsepower is constant, the pressure and the flow rate have a relationship inversely proportional to each other.

That is, when an output force of about 50% is required, the pressure is increased but the discharge flow rate is reduced and discharged through the discharge port to operate the hydraulic device. Here, since the discharge flow rate decreases, the flow rate decreases and the operating speed slows down.

In summary, in the prior art, only 1 L/m was discharged even when 50% of the output power was required, but in the case of the present invention, 2 L/m is discharged, so the discharge flow rate can be doubled and the speed can be operated twice as fast. It can.

At this time, since the maximum horsepower is exhibited in the prior art, the motor is operated at 100% and the maximum efficiency can be obtained.

Next, a state in which the maximum output force is required will be described with reference to the bar shown in FIG. 9B.

If the force corresponding to the maximum capacity of the hydraulic cylinder (maximum output force) is required, a larger pressure is applied to the outlet, so that the fluid cannot be discharged through the outlet 211, and as a result, the inside of the variable clearance (C) the pressure increases again.

So, as described above, the guide ring 510 moves further.

Likewise, when the plunger part 400 reaches the end of the cam part 300 as the guide ring 510 advances, the distance between the top dead center and the bottom dead center of the piston of the plunger part 400 at this position is It becomes S3 and has a smaller stroke distance (minimum distance) than S2, so the discharge amount is also reduced to the maximum.

That is, the amount discharged at one time from the plunger part 400 corresponds to A (cross-sectional area of the cylinder hole) × S3 (stroke distance), and is derived by one-time discharge flow rate (Q3) = A × V3 (flow rate) do.

Also, from the HP (horsepower) = P2 (pressure) × Q2/450η of the motor, the pressure and flow rate are inversely proportional to each other, so when the pressure is maximum, the discharge flow rate decreases to the minimum and operates.

In other words, the highest pressure fluid is discharged through the outlet 211 to operate the hydraulic device. Naturally, since the discharge flow rate is maximally reduced, the flow rate is maximally reduced and the operating speed is the slowest.

In summary, when 100% output power is required, 1L/m is discharged and operates at the same flow rate and speed as before.

It can be used when a large force corresponding to the maximum capacity of the hydraulic system is required.

For example, it can be used when lifting a weight of 10 tons with a hydraulic device with a capacity of 10 tons.

And when all the work is finished, the pressure applied to the outlet 211 is released and the pressure in the variable clearance (C) decreases, and the guide ring 510 is moved backward by the elasticity of the guide spring 520 to its original position. will return to

Representative embodiments of the present invention have been described above with reference to the drawings, but those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above information. Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, but should be defined by not only the claims to be described later, but also those equivalent to these claims.

100: motor 110: motor shaft
120: drive shaft 121: inclined surface
200: housing part
210: main body 211: outlet
212: second step 220: cover
300: cam part 310: camshaft
320: cam ring 330: roller bearing
340: idle axis 341: inclined block
400: plunger part
410: cylinder body 411: cylinder hole
412: suction hole 413: discharge hole
420: piston 421: spring hole
422: contact 430: piston spring
440: suction check valve 441: suction ball
442: suction spring 450: discharge check valve
451: discharge ball 452: discharge spring
500: plunger guide part
510: guide ring 511: hydraulic furnace
512: spring home 513: first step
514: decompression hole 520: guide spring
600: decompression means 610: decompression booster
611: pressure reducing cylinder 611a: pressure reducing piston
611b: small diameter part 611c: large diameter part
612: pressure reducing nozzle 613: pressure reducing oil
700: low pressure pump
E : Eccentric angle B : Bearing
R : Radius of eccentricity C : Variable play

Claims (8)

A motor, a drive shaft driven by rotation in conjunction with the shaft of the motor, a housing portion accommodating the drive shaft, a cam portion coupled to the drive shaft and rotating, and one or more plunger portions connected to the cam portion to perform pumping. In the hydraulic pump,
The cam portion is coupled to the drive shaft at an angle of inclination by a predetermined eccentricity,
When the plunger guide part formed in a ring shape and the plunger part is mounted reciprocates along the longitudinal direction of the drive shaft in the housing part,
The variable hydraulic pump, characterized in that the discharge amount of the fluid is variable in proportion to the changed stroke distance while the piston of the plunger unit moves in contact with the inclined surface of the cam unit. According to claim 1,
The cam part,
Including a camshaft inclinedly coupled to the drive shaft with a predetermined eccentricity, a camring having a cylindrical shape and surrounding the outer circumferential surface of the camshaft and contacting the piston end of the plunger, and a roller bearing provided between the camring and the camshaft Variable hydraulic pump, characterized in that consisting of. According to claim 1,
The plunger part,
A cylinder body having a cylinder hole formed therein, a suction hole through which fluid is sucked while communicating with the cylinder hole at one end, and a discharge hole through which fluid is discharged while communicating with the cylinder hole on the side of the cylinder body, and a piston spring inserted into the cylinder hole, Variable hydraulic pressure characterized in that it comprises a piston inserted into the cylinder hole to reciprocate and elastically supported by the piston spring, a suction check valve to open and close the suction hole, and a discharge check valve to open and close the discharge hole. Pump. According to claim 1,
The plunger guide part,
A guide ring formed in a circular ring shape so as to surround the drive shaft and cam at the center, reciprocating in the housing, and coupled to the plunger on the front side, provided between the guide ring and an end of the housing to make the guide ring elastic. It is made up of a supporting guide spring,
A variable hydraulic pump, characterized in that the guide ring is formed with a hydraulic path for guiding the fluid discharged from the plunger unit to an outlet formed on an outer circumferential surface of the housing unit. According to claim 4,
A stepped first step is formed on one side of the outer circumferential surface of the guide ring,
A stepped second step is formed on the other side of the inner circumferential surface of the housing part,
The variable clearance formed by the first step and the second step communicates with the hydraulic passage and the outlet,
The variable hydraulic pump, characterized in that the guide ring is moved forward while the fluid flowing through the hydraulic path fills the variable clearance. According to claim 4,
A variable hydraulic pump, characterized in that, between the outlet and the rear surface of the guide ring is further provided a pressure reducing means for reducing the pressure of the fluid discharged from the outlet and supplying it to the guide ring to advance. According to claim 6,
The pressure reducing means,
A decompression booster including a decompression cylinder connected to the outlet to reduce pressure and a decompression nozzle inserted into the rear surface of the guide ring and connected to the outlet of the decompression cylinder to supply decompressed fluid to advance the guide ring Characterized by a variable hydraulic pump. According to claim 7,
A variable hydraulic pump, characterized in that a pressure reducing valve can be used instead of the pressure reducing cylinder.

Images