JP2000329057A - Fluid pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure pump which can reduce a motor torque even when load to be applied to a piston is increased, and also reduce power consumption. SOLUTION: A swash plate device 1 has a swash plate 7 which is rotatably arranged in a tiltable manner in respect to an axial direction of a rotary shaft at its sliding surface 7a, and energized in a tilting state by means of a spring 8. Pistons 37 are inserted into a plurality of cylinder recessions 33 faced to the sliding surface 7a through check valves 34 and discharging linkage passages 35, pressurized and energized by springs 36 against the sliding surface 7a at their fronts. A cylinder device 2 has a suction port 39 for suctioning fluid into a bottom of the cylinder recession 33 due to reciprocation of the piston 37. Fluid is pressurizingly charged into a cylinder chamber 50 connected to the discharging linkage passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump having a swash plate, such as a hydraulic device.

[0002]

2. Description of the Related Art A hydraulic pump having a cylinder device in which a plurality of piston parts are protruded and urged, and a swash plate which reciprocates the piston parts by rotating the tip ends of the piston parts in a slidable manner. There is.

[0003] This fluid pressure pump can, for example, discharge into a cylinder chamber of another cylinder device to drive its external drive piston.

[0004]

However, in this fluid pressure pump, even if the external load applied to the externally driven piston is increased, the piston and the like are stroked by the same stroke amount, so that the rotational torque is increased and the power is increased. As a source, for example, there is a disadvantage that the power consumption of the motor is increased.

Accordingly, an object of the present invention is to provide a fluid pressure pump capable of reducing the rotational torque of a power source and reducing energy even when a load applied to a piston portion increases.

[0006]

According to a first aspect of the present invention, there is provided a fluid pressure pump having a rotary shaft driven by a power source, the rotary shaft having support shafts whose axial directions are different from each other. A swash plate device having a swash plate rotatably provided around the support shaft so as to be inclined with respect to the axial direction, and having a sloping posture restoring means for restoring the swash plate to an inclined posture; The cylinder has a cylinder disposed opposite to the plate, and a plurality of cylinder recesses are formed in the cylinder that are substantially parallel to the rotation axis and open toward the swash plate. The swash plate has a discharge portion capable of discharging from the cylinder recess, and is inserted into the opening of each of the cylinder recesses so as to be capable of moving forward and backward, and a tip is disposed on the swash plate so as to reciprocate in accordance with the rotation of the swash plate. The piston part has It is obtained by a cylinder device having a suction means for sucking the fluid in the bottom of the cylinder recess in operation.

According to the first aspect of the present invention, when the load applied to the piston portion increases from the load connected to the discharge section, the swash plate is pushed against the inclination posture restoring means, and the swash plate is inclined. Change the angle. When the inclination angle of the swash plate is reduced, the stroke of the piston portion is shortened, the discharge amount of the fluid is reduced, and the fluid is gradually pumped to the discharge portion, but the power source is combined with the decrease in the inclination angle of the swash plate. Therefore, low energy such as low power consumption and low torque can be realized.

[0008] The fluid pressure pump according to the second aspect is the first aspect.
Wherein the discharge section is connected to another cylinder device having an external drive piston.

According to the fluid pressure pump of the second aspect, the same effect as that of the first aspect is obtained.

A third aspect of the present invention provides a hydraulic pump.
In the above, the suction means may be provided with a suction port on the front end side of the piston portion, a discharge port on the rear end side, and a check valve operable to discharge in a passage between the suction port and the discharge port. It is provided.

According to the third aspect of the present invention, in addition to the same effects as in the second aspect, since the piston is provided on the piston without providing the suction means on the side surface of the cylinder, the cylinder is made thinner and smaller. be able to.

According to a fourth aspect of the present invention, there is provided a fluid pressure pump.
Wherein the swash plate, the piston portion and the cylinder are arranged in an oil chamber, the oil chamber is connected to an oil tank, and the cylinder chamber is connected to the oil tank via a release valve and a pressure reducing valve. It is.

According to the fluid pressure pump of the fourth aspect, in addition to the same effects as those of the third aspect, the fluid can be circulated, so that it can be effectively used as a portable pump.

According to a fifth aspect of the present invention, in the fluid pressure pump according to the first, second, third or fourth aspect, the swash plate is provided on a surface thereof with a thrust plate rotatably provided via a thrust bearing. The piston is urged in the forward direction by a spring, and the tip of the piston is pressed against the thrust plate.

According to a fifth aspect of the present invention, in addition to the same effects as those of the first, second, third, and fourth aspects, the front end of the piston portion abuts on the swash plate and slides directly. The rotation resistance of the thrust plate can be reduced, and the rotation load of the power source can be reduced as compared with the case where the thrust plate is rotated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In other words, this fluid pressure pump is an axial rotation type, and has an axial fluid pressure pump section automatic flow control mechanism having a swash plate of an automatic variable type.

In FIG. 1, a power unit to which a fluid pressure pump is applied includes a swash plate device 1, a first cylinder device 2, and a second cylinder device 3. The swash plate device 1 is attached to one end opening of a cylindrical oil chamber 4 that fills a fluid, for example, oil, and the first cylinder device 2 is a cylindrical oil chamber 4.
The oil chamber 4 is filled with oil.

The swash plate device 1 includes, for example, a motor (not shown).
Shaft 5 serving as a power transmission shaft driven by a power source such as
And a support shaft 6 whose axial direction intersects the rotation shaft 5. The support shaft 6 is rotatable about the support shaft 6 so that the sliding surface 7 a is inclined with respect to the axial direction of the rotation shaft 5. It has a swash plate 7 provided, and has a tilt posture restoring means for restoring the swash plate 7 to the inclined posture, for example, a spring 8 for urging the swash plate 7 to the inclined posture. In the embodiment, the base end 17 of the rotating shaft 5 is attached to the center of the motor mount 9 via a bearing 15, and the tip 5 a of the rotating shaft 5 is provided at the center of the first cylinder device 2 via the bearing 16. Mounted in the recess. A motor (not shown) is mounted on the motor mount 9, and the drive shaft of the motor and the end 17a of the rotary shaft 5 are connected. The motor mount 9 is in contact with an opening edge of one end of the oil chamber 4 and is fixed together with a motor by a bolt (not shown) in a screw hole 18 provided in the opening edge. The first cylinder device 2 has a screw 19 formed on the outer periphery, and is screwed and attached to a female screw formed on the inner peripheral surface at the other end of the oil chamber 4.
An O-ring 20 is attached to a peripheral groove formed on the peripheral surface of the oil chamber 4 and is in close contact with the inner periphery of the oil chamber 4 in a liquid-tight manner. Also, the motor mount 9
A projection 11 fitted into the opening of the oil chamber 4, a peripheral groove is formed on the peripheral surface of the projection 11, and an O-ring 21 is mounted in the peripheral groove. Liquid tightly adhered. 2
Reference numeral 2 denotes an oil seal provided on the projection 11.

The rotary shaft 5 is provided with a flange 24 at a position in the oil chamber 4. A long stopper 25 using, for example, a pin is provided on one side of the flange 24 with respect to the rotary shaft 5, and a pin is provided on the other side. The used short stopper 26 is provided upright.
The support shaft 6 is provided at right angles to the rotation shaft 5 in the oil chamber 4 by, for example, a fulcrum pin. The swash plate 7 is attached to both ends of the support shaft 6 with a through hole 7b at the center for inserting the rotary shaft 5, and is rotatable between a pair of stoppers 25 and 26. The rotation range is, for example, about 1.5 to 10 degrees with respect to a direction perpendicular to the rotation axis 5. The spring 8 uses, for example, a plurality of coil springs, and is compressed and interposed between the flange 24 and the swash plate 7 on the long stopper 25 side, inclining the swash plate 7 in a direction away from the flange 24, and as shown in FIG. It is locked to a short stopper 26. The spring 8 can be a leaf spring or a combination thereof in addition to a coil spring.

The first cylinder device 2 has a cylinder 30 opposed to the sliding surface 7a of the swash plate 7, and a plurality of cylinders 30 opened substantially toward the swash plate 7 substantially parallel to the rotary shaft 5. Are formed at the bottom of these cylinder recesses 33 via a first check valve 34.
3 has a discharge portion 35 capable of discharging from the cylinder recess 33
Has a piston portion 37 disposed on the swash plate 7 such that the tip is reciprocally inserted into each of the openings and the front end reciprocates in accordance with the rotation of the swash plate 7. A suction means for sucking fluid is provided at the bottom of the cylinder recess 33.

In the embodiment, the cylinder 30 of the first cylinder device 2 is attached to the other end of the oil chamber 4. As shown in FIG. 4, five cylinder recesses 33 are arranged around the center at equal intervals in the circumferential direction, and a discharge portion 35 having a first check valve 34 is provided at the bottom via a small-diameter communication passage 44. Have been.
The piston portion 37 has a distal end slidably in contact with the sliding surface 7a of the swash plate 7 and is urged by a spring 36. A spring receiving portion 46 using a ring is provided at the distal end. A spring 36, for example using a coil spring
Is fixed to the spring receiving portion 46, and the other end is connected to the cylinder 30.
The piston 37 is projected and urged, and a partial spherical surface at the tip of the piston 37 is in contact with the sliding surface 7 a of the swash plate 7. Accordingly, when the swash plate 7 rotates together with the rotation of the rotating shaft 5, the piston portion 3
7 repeats one reciprocating stroke with one rotation of the swash plate 7.

The suction means is provided with a suction port 39 at the tip end of the piston portion 37 and a discharge port 40 at the rear end side of the piston portion 37 as shown in an enlarged view in FIG. Check valve 4 operable to discharge into passage 41 between
2 are provided. The second check valve 42 is a valve, for example, a ball valve 42.
a, a spring 42b for pressing the ball valve 42a, and a screw portion 42c for supporting the spring 42b. Screw part 42c
Is screwed into a female screw formed in the discharge port 40, and the ball valve 42
a contacts the valve seat 41b at the end of the small-diameter portion 41a on the suction port 39 side of the passage 41. When the screwing amount of the screw portion 42c is adjusted, the force with which the ball valve 42a presses the valve seat 41b is adjusted. The suction port 39 is located in the oil chamber 4 at the time of the suction operation in which the cylinder recess 33 advances toward the swash plate 7 side.
Since the volume of the cylinder 3 increases, the cylinder recess 33 becomes negative pressure, the ball valve 42a of the second check valve 42 is opened from the valve seat 41b, and the oil in the oil chamber 4 is sucked into the cylinder recess 33 from the suction port 39. (FIG. 8 (b)). On the other hand, piston part 3
7, the volume of the cylinder recess 33 decreases during the retreat operation, and the oil in the cylinder recess 33 is pressurized. However, the second check valve 42 is opened because the ball valve 42a is pressed in the direction to close the valve seat 41b. And remains closed (FIG. 8 (a)).
Therefore, the pressurized oil flows into the discharge unit 35 as described later.

The second cylinder device 3 has a cylinder chamber 50 serving as a discharge chamber of the first cylinder device 2 connected to the discharge section 35, and has an external drive piston 51 inserted into the cylinder chamber 50. . The external drive piston 51 has a contact portion 55 and a contact portion 55 slidably contacting the inner peripheral surface of the cylinder chamber 50.
And the driving piece 56 provided at the center of the An O-ring 57 is provided in a circumferential groove on the outer peripheral surface of the contact portion 55, and is in fluid-tight contact with the inner peripheral surface of the cylinder chamber 50. The external drive piston 51 is urged by a spring 90 in a direction to reduce the internal volume of the cylinder chamber 50. The spring 90 of the embodiment is a coil spring. The coil spring is passed through the driving piece 56, and one end is locked to the contact portion 55, and the other end is locked to the power unit main body 120 mounted on the cylinder chamber 50. Thus, the external drive piston 51 is urged toward the first cylinder device 2.

The end of the oil chamber 4 on the first cylinder device 2 side is attached to the bottom wall 50a of the cylinder chamber 50. The discharge unit 35 is configured to extend over the first cylinder device 2 and the second cylinder device 3, and an end of the discharge unit 35 communicates with the cylinder chamber 50. The first check valve 34 includes a discharge unit 35
And a valve, such as a ball valve, supported at one end of the spring and abutting on a valve seat at the boundary between the discharge portion 35 and the communication portion 44 supported by the tip of the spring. Therefore, when the cylinder concave portion 33 of the first cylinder device 2 is compressed by the piston portion 37, the pressure of the communication portion 44 increases, the ball valve is pushed from the valve seat and the valve is opened, and the oil of the cylinder concave portion 33 is discharged from the discharge portion 35. Then, the oil flows into the cylinder chamber 50 and the oil accumulates in the cylinder chamber 50. As described above, the external drive piston 55 of the second cylinder device 3 is provided with the spring 90 in the direction of compressing the cylinder chamber 50.
1 is retracted into the cylinder chamber 50, but is pressed by the pressurization of oil by the reciprocating operation of the piston portion 37 of the first cylinder device 2, and the external drive piston 51 advances outward against the spring 90. I do. On the other hand, the reverse flow of the oil is prevented because the ball valve of the first check valve 34 is pressed against the valve seat by the oil and comes into close contact therewith.

As described above, the swash plate 7, the piston 37
And the cylinder 30 are disposed in the oil chamber 4, the oil chamber 4 is connected to the oil tank 100, and the cylinder chamber 50
Is connected to the oil tank 100 via a release valve 70 and a pressure reducing valve 60.

As shown in FIG. 2, a pressure reducing valve 60 is provided in the bottom wall 50a of the cylinder chamber 50. This pressure reducing valve 6
Reference numeral 0 denotes a bottomed hole 61 opened on the side surface of the bottom wall 50a, a small-diameter communication passage 62 communicating with the inside of the cylinder chamber 50 at the bottom of the bottomed hole 61, and a communication passage 62 inserted into the bottomed hole 61. Of a third check valve having a conical portion for closing the outlet of the valve, a spring 64 for pressing the valve body 63 toward a valve seat, and a bottomed hole 61
And a pressure adjusting portion 65 that supports a spring by providing a screw that engages with a female screw formed on the opening side of the spring. The spring pressure of the spring 64 is changed according to the screwing amount of the pressure adjusting section 65 to adjust the pressure for pressing the valve body 63 against the valve seat, so that the pressure becomes equal to the oil pressure in the communication passage 62 communicating with the cylinder chamber 50. The position, that is, the pressure at which the valve body 63 is pushed by the oil pressure to open and decompress the cylinder chamber 50 is adjusted. The pressure adjusting section 65 is provided with an O-ring 66 in an outer circumferential groove to prevent oil leakage. 67 is an outlet formed on the side of the bottomed hole 61.

As shown in FIG. 3, a release valve 70 is provided on the bottom wall 50a of the cylinder chamber 50. Release valve 70
A valve chamber 72 of a fourth check valve communicating with the cylinder chamber 50 through a communication section 71, and an end of the valve chamber 72 and a small-diameter communication passage 7;
The valve chamber 72 is provided with a valve for closing a communication passage 73 communicating with the operation chamber 74, for example, a ball valve 75.
Is pressed by a spring 76. The operation chamber 74 is opened on the outer surface of the bottom wall 50a, the end of the operation piece 77 protrudes from this opening, and is urged to protrude to the outside by a spring 78.
A push piece 79 capable of pressing the ball valve 75 through the communication passage 73 is provided at the inner end of the nozzle 7. Reference numeral 80 denotes an oil outlet formed on the side of the operation chamber 74. When the external drive piston 51 of the second cylinder device 3 is to be retracted, the operating piece 77 is pushed and the ball valve 75 is pushed open by the pushing piece 79 against the spring 76, so that the oil in the cylinder chamber 50 has the pressure. Communication path 7
The oil flows from the oil outlet 80 through the operation chamber 74 to the outside of the cylinder chamber.

As shown in FIG. 1 again, an oil tank 100 adjacent to the oil chamber 4 is provided on the bottom wall 50a of the cylinder chamber 50.
And a communication path 101 that connects the oil tank 100 and the four oil chambers is formed in the bottom wall 50a, and a filter 103 is mounted at an outlet on the oil tank 100 side.
The outlet 67 of the bottomed hole 61 of the pressure reducing valve 60 and the oil outlet 80 of the operation chamber 74 of the release valve 70 are connected to the oil tank 100.
Contact Oil tank 100 is formed of a flexible member.

The operation of the power unit using this fluid pressure pump will be described. 1 and 5 show the operation at the time of pressurization, in which the external drive piston 51 of the second cylinder device 3 is retracted by the spring 90, and the cylinder chamber 50 is in the minimum space. Is also at the lowest oil pressure. At this time, the swash plate 7 is pressed against the short stopper 26 by the spring 8 of the swash plate 7. When the motor rotates, the rotating shaft 5 and the swash plate 7 rotate, the piston 37 slides on the sliding surface 7a, and the piston 37 reciprocates in the axial direction. In this reciprocating operation, when the piston portion 37 moves toward the swash plate 71 from the cylinder recess 33 by the spring 36, the cylinder recess 3
As the internal volume of the cylinder 3 increases, oil is sucked into the cylinder recess 33 from the suction port 39, and when the piston portion 37 is retracted into the cylinder recess 33 by the swash plate 7, the cylinder recess 3
Compress the internal volume in 3. At the time of this compression, the piston part 3
In 7, the second check valve 42 does not flow backward to the suction port 39 side, but pushes and opens the first check valve 34 of the communication portion 35 to pump oil into the cylinder chamber 50. The piston portion 37 makes one reciprocation with one rotation of the swash plate 7, but since the inclination angle of the swash plate 7 is the maximum at this time, the reciprocation stroke of the piston portion 37 is also maximum, and therefore, the oil pressure per one reciprocation is sent. The amount is also maximum. In the cylinder chamber 50 in the second cylinder device 3 in which the oil is pumped from the piston portion 37, the internal pressure of the cylinder chamber 50 is sequentially increased by the oil, and the external drive piston 51 moves forward.

FIG. 2 and FIG. 6 show the operation up to the pressure reducing valve operation for keeping the maximum pressure constant.
Is pressed. Therefore, the first check valve 34
A load is applied to the discharge operation of the piston portion 37 that generates a hydraulic pressure that pushes the spring, and the spring 8 of the swash plate 7 that pushes the piston portion 37 is pressed.
, And the spring 8 is elastically deformed. As a result, when the oil pressure exceeds the spring force of the spring 8 in the cylinder chamber 50, the spring 8 is compressed and deformed accordingly, and the inclination angle of the swash plate 7 approaches the direction perpendicular to the rotary shaft 5, and the spring 8 It will have a tilt angle with balanced pressure. Also, since the piston load is applied at the time of discharge,
When the swash plate 7 is rotated, the piston 37 is pushed in when the swash plate 7 is pushed. When the angle of the swash plate 7 with respect to the piston portion 37 is reduced, the reciprocating stroke of the piston portion 37 is reduced, and the load on the motor is also reduced. When the maximum load is applied, the swash plate 7 is engaged with the long stopper 25, but also at this time, the swash plate 7 has an inclination (for example, about 1.5 °) for reciprocating the piston portion 37. In this case, the pressure in the cylinder chamber 50 is kept constant by the operation of the pressure reducing valve 60. The operation of the pressure reducing valve 60 is adjusted by the pressure adjusting unit 65,
Set to maximum pressure. Therefore, the pressure reducing valve 60 is opened for a certain pressure or more of the oil. The swash plate 7 may be inclined so that the piston portion 37 does not reciprocate when the load is the maximum.

FIG. 7 shows a release operation.
When the button 7 is pressed, the release valve 70 is pressed to open the valve, and the oil in the cylinder chamber 50 flows out of the cylinder chamber 50 to reduce the pressure. Due to the decrease in pressure, the spring 90 of the external drive piston 51 returns and pushes back the external drive piston 51, so that oil is pushed out and the spring 8 of the swash plate 7
The swash plate 7 is again inclined at the maximum angle and locked on the short stopper 26 because the load is not applied to the swash plate 7.

When the motor is kept running, the external drive piston 51 reciprocates in this step, so that the motor can be operated continuously. However, the motor is stopped every time the piston 51 moves backward. Is also good.

The circulation of the oil will be described. The oil is filled in the oil chamber 4 and the oil tank 100, and communicates with each other through the communication passage 101 and the filter 103. The oil tank 100 is, for example, a flexible tank having a capacity of about 55 cc as described above. Oil chamber 4
When the oil is sucked into the cylinder concave portion 33 by the discharge operation of the piston portion 37, the oil flows into the oil chamber 4 sequentially from the oil tank 100 through the filter 103 and the communication passage 101, and the oil tank 100 is flexible. Therefore, they contract as shown in FIGS. The oil sucked into the cylinder recess 33 is sequentially transferred to the second cylinder device 3
The cylinder 51 is pressure-fed to the inside, and the volume of the cylinder chamber 50 is expanded by the movement of the piston 51. Cylinder chamber 5
When the oil pressure is 0, the pressure reducing valve 60 is opened when the pressure is reduced, and the oil is returned to the oil tank 100. When the oil is released, the release valve 70 is opened and the oil is returned to the oil tank 100. Thus, the oil circulates.

According to the first embodiment, when the hydraulic pressure of the second cylinder device 3 is low and the force for pushing up the piston is less than the compression load of the spring 8, the inclination angle of the swash plate 7 is large and the discharge amount is large. At this time, since the shaft rotation torque (load) has a small load, a large discharge amount can be obtained with less power to the fluid pressure pump. When the hydraulic pressure is high and the piston pushing-up force compresses the spring 8, the inclination angle of the swash plate 7 changes according to the piston pushing-up force. At this time, the shaft rotation load is usually very large. However, since the inclination angle of the swash plate 7 is reduced due to the bending of the spring 8, a discharge amount corresponding to a small piston lifting force is obtained with a small shaft rotation torque. As a result, low fuel consumption and low power can be realized as compared with the conventional example in which the inclination angle is fixed.

FIGS. 9 and 10 show a second embodiment of the present invention. That is, in this fluid pressure pump, the swash plate 7 is rotatably provided via the thrust bearing 125 instead of directly sliding the tip of the piston portion 37 on the swash plate 7 as in the first embodiment. The front end of the piston portion 37 is pressed against the thrust plate 126. Specifically, a circular concave portion 128 is formed on the surface of the swash plate 7, and a ring-shaped groove 127 is formed on the bottom of the circular concave portion 128.
Are a plurality of thrust roller bearings inserted into the ring-shaped groove 127, and the thrust plate 126 is fitted in the circular recess 128 and supported by the thrust bearing 125. 130 is a motor.

FIG. 9 shows a case where the swash plate 7 has a maximum inclination angle of 10 °. At this time, if the lift amount L1 of the piston portion 37 for pushing up the oil into the cylinder chamber 50 by the cylinder recess 33 is 0.3791 cm, for example, the cylinder recess Assuming that the diameter of the cylinder 33 is 0.4 cm and the number of the cylinder recesses 33 is 5, the discharge amount is (0.4 / 2) ² × 3.14 × 0.1.
3791 × 5 = 0.238 CC / 1 cycle.

FIG. 10 shows a case where the swash plate 7 has a minimum inclination angle of 1.5 °.
The lift amount L2 for pushing up the oil to 0 is set to 0.05, for example.
Assuming 64 cm, the discharge amount is (0.4 / 2) ² × 3.
14 × 0.0564 × 5 = 0.035 CC / 1 cycle. The other parts are the same as those of the first embodiment, and the common parts are denoted by the same reference numerals.

According to the second embodiment, the piston 3
As compared with a structure in which the tip of the thrust plate 7 abuts on the swash plate 7 and slides directly, the rotational resistance of the thrust plate 126 can be reduced, and the rotational load of the motor 130 can be reduced.

FIG. 11 is a graph in which the horizontal axis represents time (seconds) and the vertical axis represents motor current (A). A ₁ is the maximum angle 10 ° hydraulic pump by fixing the swash plate to the inclination of the graph ,, A ₂ is the minimum angle 1.5 ° in the case of operating the hydraulic pump by fixing the swash plate to the inclination angle of graph when the driving, a ₃ is a graph of the embodiment swash plate 7 is automatically changed range of the angle 1.5 ° to 10 °. When the swash plate 7 is rotated and oil is discharged from the first cylinder device 2 to the second cylinder device 3, the total discharge amount of oil, and therefore the maximum pressure applied to the external drive piston 51, is the same constant value in each case. and then, the time required to reach this maximum pressure serves as a final position a ₁ ~a ₃ of each graph.
At this time, the area under each graph, that is, current × time (A
S): Graph A ₁ is 203 AS, graph A ₂ is 199
AS, graph A ₃ was 136AS. From this result, it can be seen that the graphs A ₁ and A ₂ have little change even if the angle of the swash plate 7 is different, but the graph A ₃ is reduced to about 67% of the graph A ₁ . Current (A) x time (S)
Is multiplied by the applied voltage (V) of the motor, the electric power is obtained. Therefore, since each value is proportional to the electric power, it is understood that the present invention can reduce the power consumption as compared with the conventional example.

FIG. 12 shows still another embodiment. That is, in the fluid pressure pump, the rotary shaft 5 and the support shaft 6 intersect in the same plane in the first embodiment and the like, but they are so-called three-dimensionally intersected in different planes. Instead of providing the support shaft 6 on the rotary shaft 5 as in the first embodiment, the support shaft 6 is provided in a notch 24 a formed in the flange 24 of the rotary shaft 5, and the rotary shaft 5 is made to pass through the center of the swash plate 7. The projecting leg 7b provided at the end of the swash plate 7 may be rotatably supported by the support shaft 6 of the notch 24a located on the opposite side of the rotation shaft 5 from the rotation shaft 5. In this case, one end of the swash plate 7 is pushed up by the spring 8, and the swash plate 7 is biased to be inclined about the support shaft 6 at the other end. The position of the support shaft 6 with respect to the swash plate 7 may be near the trajectory where the piston portion 37 rotates on the swash plate 7, but is preferably outside the trajectory.

In the present invention, the fluid may be other than oil.

A rotating shaft 5 for supporting a supporting shaft 6 of the swash plate 7
A long hole may be formed in at least one of the swash plate 7 and the support shaft 6 may be moved according to a change in the inclination angle of the swash plate 7.

The fluid pressure pump of the present invention can be applied to drive a lift, drive a hydraulic unit, drive a device connected by a fluid hose, and the like.

Although the suction means is provided in the piston portion 37, it may be provided with a check valve on the side of the cylinder recess 33, in which case the swash plate 7 does not have to be immersed in oil.

Further, the piston portion 37 of the first embodiment
May have a ball joint provided with a shoe. The tip of the piston portion 37 of the second embodiment may be connected to the thrust plate 126 by a ball joint or the like, and the spring for urging and pushing the piston portion 37 may be omitted.

Further, as the means for restoring the inclined posture of the swash plate 7, there are a magnet 8 utilizing a magnetic force in addition to the spring 8. Further, the spring 36 may be interposed between the end surface of the piston portion 37 and the bottom surface of the cylinder recess 33 in the cylinder recess 33.

The spring 42b of the second check valve 42 is shown in FIG.
The ball valve 4 is supported by the screw portion 42c as shown in FIG.
It may be interposed between 2a and the bottom of the cylinder recess 33.

[0048]

According to the fluid pressure pump according to the first aspect,
When the load applied to the piston portion increases from the load connected to the discharge section, the swash plate is pushed against the inclination posture restoring means to change the inclination angle of the swash plate. When the inclination angle of the swash plate is reduced, the stroke of the piston portion is shortened, the discharge amount of the fluid is reduced, and the fluid is gradually pumped to the discharge portion, but the power source is combined with the decrease in the inclination angle of the swash plate. Therefore, low energy such as low power consumption and low torque can be realized.

According to the fluid pressure pump of the second aspect, the same effect as that of the first aspect is obtained.

According to the third aspect of the present invention, in addition to the same effects as those of the second aspect, since the piston is provided on the piston without providing the suction means on the side surface of the cylinder, the cylinder is made thinner and smaller. be able to.

According to the fluid pressure pump of the fourth aspect, in addition to the same effects as those of the third aspect, the fluid can be circulated and thus can be effectively used as a portable pump.

According to the fluid pressure pump according to the fifth aspect, in addition to the same effects as those of the first, second, third or fourth aspect, the front end of the piston portion comes into contact with the swash plate and slides directly. The rotation resistance of the thrust plate can be reduced, and the rotation load of the power source can be reduced as compared with the case where the thrust plate is rotated.

[Brief description of the drawings]

FIG. 1 is an enlarged partial cross-sectional view showing an operation state during pressurization according to a first embodiment of the present invention.

FIG. 2 is an enlarged partial cross-sectional view illustrating a state during a pressurizing operation and a state during a pressure reducing valve operation.

FIG. 3 is a partial sectional view illustrating the operation of a swash plate.

FIG. 4 is an enlarged partial sectional view of a state during a release operation.

FIG. 5 is an explanatory view of the first cylinder device as viewed in an axial direction.

FIG. 6 is a partial cross-sectional side view of an operation state during pressurization.

FIG. 7 is a partial cross-sectional side view during the pressurizing operation and the pressure reducing valve operation.

FIG. 8 is an enlarged sectional view showing a check valve of a piston portion;
(A) is a state where the check valve is closed, and (b) is a state where the check valve is open.

FIG. 9 is a partial cross-sectional view of the second embodiment at the time of initial pressurization.

FIG. 10 is a partial sectional view at the time of maximum pressurization.

FIG. 11 is a graph of motor current versus time for the present invention and the prior art.

FIG. 12 is a partial cross-sectional view of another embodiment when stopped.

[Explanation of symbols]

 Reference Signs List 1 swash plate device 2 first cylinder device 3 second cylinder device 4 oil chamber 5 rotation shaft 6 support shaft 7 swash plate 8 spring 25 stopper 26 stopper 30 first cylinder 33 cylinder recess 34 first check valve 35 Discharge part 36 Spring 37 Piston part 39 Suction port 40 Discharge port 42 Second check valve 50 Cylinder chamber 51 External drive piston 60 Pressure reducing valve 70 Release valve 90 Spring 100 Oil tank 120 Power unit main body 125 Thrust bearing 126 Thrust plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kunihiko Ryu 1048 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Inventor Yuichi Higuchi 3-1-1, Fukuichi-cho, Higashi-Osaka-shi, Osaka Prefecture Inside Takako Corporation (72) Inventor Yoshitaka Minami 3-1-48, Fukuichi-cho, Higashi-Osaka City, Osaka Takanaka Inn (72 ) Inventor Yoshiko Ishizaki 3-48, Fukuichicho, Higashiosaka-shi, Osaka F-term in Takako Co., Ltd. (Reference) 3H070 AA01 BB04 BB17 BB25 CC21 DD52 DD66

Claims (5)

[Claims] A rotating shaft driven by a power source;
The rotary shaft has a support shaft having different axial directions, and a swash plate rotatably provided around the support shaft so as to be inclined with respect to the axial direction of the rotary shaft. A swash plate device having an inclined posture restoring means for restoring the swash plate to an inclined posture, and a plurality of cylinders having a cylinder disposed opposite to the swash plate and opening toward the swash plate substantially parallel to the rotation axis. A cylinder recess is formed, and a discharge portion capable of discharging from the cylinder recess via a check valve is provided at the bottom of the cylinder recess, and the tip is obliquely inserted into the opening of each of the cylinder recesses and the tip is inclined. A cylinder device having a piston portion disposed on the swash plate so as to reciprocate in accordance with the rotation of the plate, and having suction means for sucking fluid at the bottom of the cylinder recess by the advancement of the piston portion; Fluid pressure pon with H. 2. The hydraulic pump according to claim 1, wherein the discharge unit is connected to another cylinder device having an external drive piston. 3. The reverse suction means is provided with a suction port on the front end side of the piston portion, a discharge port on a rear end side, and capable of performing a discharge operation in a passage between the suction port and the discharge port. 3. The fluid pressure pump according to claim 2, further comprising a stop valve. 4. The swash plate, the piston portion and the cylinder are disposed in an oil chamber, the oil chamber is connected to an oil tank, and the cylinder chamber is connected to the oil tank via a release valve and a pressure reducing valve. The fluid pressure pump according to claim 3, wherein 5. The swash plate has on its surface a thrust plate rotatably provided via a thrust bearing,
5. The fluid pressure pump according to claim 1, wherein said piston portion is urged in a forward direction by a spring, and a tip of said piston portion is pressed against said thrust plate.