JPH0861222A - Variable phase type piston pump - Google Patents

Abstract

PURPOSE: To increase a discharge rate of a variable phase type piston pump, reduce a size and weight of a device, and improve its durability. CONSTITUTION: A rotor 2 is provided with a flange-like disc 2a and a shaft cylinder 2b. Holes 5, 6 are formed on an outer periphery of the shaft cylinder 2b, which holes 5, 6 are communicated with cylinder holes 4 formed on the disc 2a. An inner peripheral surface of a stator 7 which externally surrounds the disc 2a is divided into semi-cylindrical surfaces. A piston 10 is arranged in each cylinder hole 4. Rectifying grooves 18, 19, 20, 21 are independently formed every 90 degree phases on an inner surface of a rectifying block 17 which externally surrounds an opening 6a formed on the shaft cylinder 2b. The two pairs of rectifying grooves are opposed to each other across a center of the rotor 2. Among them, the grooves 18, 20 are connected to one intake/ discharge hole 22 of a pump, while the grooves 19, 21 are connected to the other intake/discharge hole 23 of the pump. The stator 7 can be rotationally controlled in respect to the rectifying block 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable phase piston pump in which a plurality of pistons are arranged in a radial direction with respect to a rotor and the discharge volume thereof is variable.

[0002]

^2. Description of the Related Art As a hydraulic pump for generating a high pressure of about 210 kg / cm.sup.2, there is no other hydraulic pump on the market at present than a piston type pump, and no variable displacement type other than a swash plate type. This swash plate type piston pump changes the stroke of the piston to make the discharge capacity variable, but there is a problem with the link mechanism between the input shaft and the swash plate and the piston and the swash plate, and where reliability is truly required, The reality is that they are shunned. Oil leakage from the valve plate for switching oil in and out of the cylinder chamber is also a big problem.If oil leakage is reduced, frictional resistance increases, and if the frictional resistance is disliked, oil leakage cannot be ignored. Could not be resolved.

From the above viewpoint, the present applicant has previously proposed a hydraulic piston device (Japanese Patent Laid-Open No. 2-256883) capable of varying the discharge capacity while keeping the stroke of the piston constant. This device has an advantage in that it has a simpler structure than the conventional variable displacement pump and can be used for high pressure because it is a piston pump.

[0004]

However, in the above-mentioned conventional device (Japanese Patent Laid-Open No. 2-256883), since the inner peripheral surface of the stator or the outer peripheral surface of the eccentric cam is a perfect circle, 0 out of 360 °. If the angle of suction is from 180 ° to 180 °,
Since the range of 180 ° to 360 ° is on the discharge side (high pressure side), a large load acts on the bearing portion of the rotating body, resulting in an increase in the size of the device and adversely affecting durability. was there.

[0005]

In order to solve the above problems, in the present invention, a rotor fixed to a shaft is provided with a collar-shaped disc portion and a shaft cylinder portion, and the rotor is arranged from the outer peripheral surface of the disc portion. A plurality of bottomed cylinder holes facing the center of each of the cylinder holes, the holes communicating with the bottoms of the cylinder holes are provided on the outer peripheral surface of the shaft cylinder part, respectively, and the inner circumference of the stator enclosing the disc part is enclosed. The surface is formed into two semi-cylindrical surfaces each having an eccentric center on both sides from the center of the rotor, and a piston that slides along the inner peripheral surface of the stator is provided in each of the cylinder holes. An independent rectifying groove is provided for each 90 degree phase on the inner surface of the rectifying block that encloses the provided opening, and one of the two rectifying grooves facing the center of the rotor is connected to one of the suction and exhaust holes of the pump. And adjust the two sets Connect the other groove to the other suction and discharge hole of the pump, constituting the variable phase type piston pump to the stator to rotate control on the rectifier block.

The stator of the apparatus of the first aspect of the invention may be fixed, and the commutation block may be rotationally controlled with respect to the stator.

[0007]

Since the piston pump of the present invention is constructed as described above, each piston in each cylinder hole makes two strokes while the rotor makes one revolution. Therefore, as compared with the conventional pump described above, in which the piston makes one stroke while the rotor makes one rotation, the pump of the present invention has a double discharge amount if other specifications are the same. become.

Further, since the hydraulic pressures acting on the flow regulating grooves in the flow regulating block of the present invention are the same as each other facing the center of the rotor, the loads due to the hydraulic pressures acting on the respective rotors are balanced. Become. Therefore, according to the present invention, the load acting on the bearing portion of each rotating body is reduced, and as a result, the device is reduced in size and weight, and the durability is also improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, 1 is an output shaft of an electric motor which is a prime mover, and 2 is a rotor fixed to the shaft 1 by a key 3. The rotor 2 is provided with a collar-shaped disc portion 2a and a shaft cylinder portion 2b, and a plurality of bottomed cylinder holes 4 (in this embodiment, from the outer peripheral surface of the disc portion 2a toward the center of the rotor 2). (5 pieces) Provided at equally divided positions on the circumference.

Further, a hole 5 communicating with the bottom of each cylinder hole 4 is provided in the shaft cylindrical portion 2b in parallel with the center line of the shaft, and a hole 6 orthogonal to this hole 5 is formed from the outer peripheral surface of the shaft cylindrical portion 2b. The openings 6a are opened and arranged on the same plane orthogonal to the center line of the shaft tube portion 2b.

Further, the inner peripheral surface of the stator 7 which encloses the disk portion 2a is eccentric to the both sides from the center 0 (see FIG. 2) of the rotor 2 by l, and the radius R is centered around points 0 ₁ and 0 ₂ . Two semi-cylindrical surfaces 8 and 9 are formed. Further, a piston 10 that slides along the inner peripheral surfaces 8 and 9 of the stator 7 is provided in each of the cylinder holes 4.

Reference numeral 11 (see FIGS. 2 and 3) is a roller rotatably fitted to the outer end portion of each piston 10 and the stator 7 is provided.
10a which rolls in contact with the inner peripheral surfaces 8 and 9 of the
(See FIG. 3) is a small hole provided in the concave portion of the piston 10 that supports the roller 11, and oil leaked from the small hole 10a lubricates the rotating surface of the roller 11. 1
2 is a coil spring provided in the piston 10,
It always acts to push 0 outward. If the oil on the suction side is pressurized, the oil is naturally pushed into the cylinder hole 4, and the coil spring 12 is not necessary.

Reference numeral 13 (see FIG. 1) is a side plate applied to the open end surface of the stator 7, and 14 is a fastening bolt thereof. Reference numeral 15 is a ball bearing provided between the rotor 2 and the stator 7 and the side plate 13, and 16 is a snap ring.

Further, as shown in FIGS. 1 and 4, the rectifying block 17 is provided so as to enclose the shaft tube portion 2b of the stator 2.
Is provided on the inner surface of the rectifying block 17, and the rectifying grooves 18, 19, 20, 2 communicating with the opening 6a provided in the shaft tube portion 2b.
1 is independently provided on the inner surface of the rectifying block 17 for each 90 degree phase.

One of the two straightening grooves 18, 20 and 19, 21 facing the center 0 of the rotor 2
8 and 20 are connected to one of the suction / exhaust holes 22 and 23 of the pump through an oil passage 24, and the other 19 and 21 of the two sets of rectifying grooves are connected to the other 23 of the suction / exhaust holes of the pump through an oil passage 25. And connect the stator 2 to the rectification block 17
To be able to control rotation.

Reference numeral 26 in FIG. 1 indicates the shaft cylinder portion 2 of the rotor 2.
Reference numeral 28 denotes an end cap which is applied to the end surface of b and fastened to the shaft 1 by a bolt 27, and 28 denotes an O-ring for sealing the opening end of the hole 5 in the shaft tubular portion 2b.

Further, the stator 2 of the first aspect of the invention may be fixed, and the commutation block 17 may be rotationally controlled with respect to the stator 2. The rotation control means of the stator 2 and the rectification block 17 may be any method.

Next, the operation of the variable phase type piston pump of the present invention constructed as described above will be explained. When the output shaft 1 of the prime mover rotates and the stator 2 rotates in the direction of arrow A in FIGS. 2 and 4, the piston 10 located in the 0 ° phase in FIG. As it moves along, it continues to move outwards up to the 90 ° phase. That is, the pump formed by the cylinder 4 and the piston 10 acts as an intake from 0 ° to 90 °.

Next, when the stator 2 further rotates and the piston 10 moves from 90 ° to 180 °, the piston 10 moves inward along the inner peripheral surface 8 of the stator 7 during this period, so that the pump discharges. It will be a journey.

When the stator 2 further rotates and the piston 10 moves from 180 ° to 270 °, the piston 10 moves outward along the inner peripheral surface 9 of the stator 7 during this period, so that the pump is in the suction stroke. And 270 ° ~
At 360 °, the piston 10 moves inward and the pump enters the discharge stroke.

That is, in the pump of the present invention, while the shaft 1 makes one rotation, the pump performs the strokes from the suction to the discharge twice. Further, in this embodiment, there are five pistons 10 in the rotor 2, but each piston 10 performs the same operation as described above.

When the phases of the stator 7 and the rectifying block 17 are in the phases shown in FIGS. 2 and 4, as described above,
The rectifying grooves 18 and 20 are on the suction side, and the rectifying grooves 19 and 21 are on the discharge side. Therefore, in this case, the suction hole 2 of the pump
The oil is sucked in from the nozzle 2 and the pressure oil is discharged from the discharge hole 23.

Next, when the stator 7 is rotated 22.5 ° in the clockwise direction as shown in FIG. 5 and the piston in the phase of 0 ° is rotated from 0 ° to 90 °, the straightening groove 1
8. Discharge oil enters 0 to 22.5 °, and 22.
Oil is sucked through the flow straightening groove 18 from 5 ° to 90 °. This phenomenon is caused by 90 ° to 180 °, 180 ° to 270 °, 2
The same is true in the range of 70 ° to 0 °. That is, in this case, the range of 22.5 ° is the discharge stroke, and 90 ° -2
The range of 2.5 ° = 67.5 ° is the intake stroke. Therefore, since the net discharge stroke is in the range of 67.5 ° -22.5 ° = 45 °, the discharge amount of the pump in this case is 1/2 that when the stator 7 is not rotated.

Next, as shown in FIG. 6, the stator 7 is
When the piston, which was in the 0 ° phase while being rotated by 45 ° in the clockwise direction, rotates from 0 ° to 90 °, discharge oil enters the flow straightening groove 18 from 0 ° to 45 °, and 45 ° to 90 °. Since the intake stroke is up to 0, the oil inflow and outflow of the flow straightening groove 18 will be 0 in the end. In addition, the intake stroke is from 90 ° to 135 °, and the discharge stroke is from 135 ° to 180 °.
The oil flow in and out of the flow regulating groove 19 is also zero. Similarly, the oil flow into and out of the flow straightening grooves 20, 21 becomes zero.

Further, as shown in FIG. 7, when the piston, which is in the phase of 0 °, rotates from 0 ° to 90 ° while the stator 7 is rotated 90 ° in the clockwise direction, the straightening groove 18 becomes 0 °. The discharged oil enters from 90 ° to 90 °, and the suction stroke through the flow straightening groove 19 occurs from 90 ° to 180 °. This is opposite to the pump in the states of FIGS. 2 and 4 described above in suction and discharge.

Thus, according to the invention, the stator 7
By rotating the phase from 0 ° to 90 °, the discharge amount can be continuously changed to 0, and
The directions of inhalation and exhalation can also be reversed. Although the case where the phase of the stator 7 is changed has been described above,
Even if the phase of the rectification block 17 is changed instead of the stator 7, the same effect can be obtained.

As described above, according to the present invention, it is possible to arbitrarily control the oil discharge direction and the capacity while keeping the rotation direction and the rotation speed of the rotor constant. Further, even if the rotation direction of the rotor is changed, the oil discharge direction can be reversed. Therefore, the oil discharge direction can be controlled by shifting the phase of the stator 7 and the rectification block 17 or by changing the rotation direction of the rotor 2. Therefore, when actually designing the hydraulic system, according to the present invention, The degree of freedom is expanded. Although the present invention has been described as a pump in the above description, it goes without saying that the present invention is also applicable as a variable phase piston motor because the hydraulic pump can be used immediately as a hydraulic motor.

[0028]

Since the piston pump of the present invention is constructed as described above, each piston 10 in each cylinder hole 4 makes two strokes while the rotor 2 makes one revolution. Therefore, as compared with the conventional pump described above, in which the piston makes one stroke while the rotor makes one rotation, the pump of the present invention has a double discharge amount if other specifications are the same. The effect of becoming is obtained.

Further, the hydraulic pressures acting on the rectifying grooves 18 to 21 in the rectifying block 17 of the present invention are equal to each other facing the center of the rotor 2, so that the load due to the hydraulic pressure acting on each rotating body is applied. All will come to balance. Therefore, according to the present invention, the load acting on the bearing portion of each rotating body is reduced, and as a result, the device is reduced in size and weight, and the durability is also improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a device of the present invention.

2 is a cross-sectional view taken along line XX of the apparatus of FIG. 1 with a side plate and a bearing removed.

3 is a partial cross-sectional view of one of the pistons of FIG.

FIG. 4 is a sectional view taken along line YY of FIG.

FIG. 5 is an operation explanatory view of the stator of FIG. 2 rotated 1/16.

FIG. 6 is an operation explanatory view of the stator of FIG. 2 rotated 1/8.

FIG. 7 is an explanatory view of the operation of rotating the stator of FIG. 2 by 1/4.

[Explanation of symbols]

 1 shaft (motor output shaft) 2 rotor 2a disk part 2b shaft cylinder part 3 key 4 cylinder hole 5 hole 6 hole 6a opening 7 stator 8 and 9 semi-cylindrical surface (inner peripheral surface) 10 piston 10a small hole 11 roller 12 Coil spring 13 Side plate 14 Fastening bolt 15 Ball bearing 16 Snap ring 17 Straightening block 18, 19, 20, 21 Straightening groove 22, 23 Pump suction / discharge hole 24, 25 Oil passage 26 End cap 27 Bolt 28 O-ring

Claims (2)

[Claims] 1. A rotor fixed to a shaft is provided with a flange-shaped disc portion and a shaft cylinder portion, and a plurality of bottomed cylinder holes are provided from the outer peripheral surface of the disc portion toward the center of the rotor. Two holes, which communicate with the bottom of the hole, are provided by opening on the outer peripheral surface of the shaft cylindrical portion, and the inner peripheral surface of the stator enclosing the disk portion has two eccentric centers on both sides of the rotor center. A piston that is formed on a semi-cylindrical surface and that slides along the inner peripheral surface of the stator is provided in each of the cylinder holes, and the inner surface of the rectifying block that encloses the opening provided in the shaft tubular portion is provided for each 90 degree phase. An independent rectifying groove is provided, one of the two rectifying grooves facing the center of the rotor is connected to one of the suction / exhaust holes of the pump, and the other of the two rectifying grooves is connected to the suction / exhaust hole of the pump. Connect to the other,
A variable phase type piston pump characterized in that the stator can be rotationally controlled with respect to the flow control block. 2. A variable phase piston pump characterized in that the stator according to claim 1 is fixed and the commutation block can be rotationally controlled with respect to the stator.