JPH03279679A - Hydraulic pump - Google Patents

Abstract

PURPOSE:To obtain a hydraulic pump of excellent handling property by providing a drain passage communicated to a hollow chamber on the upper position above the communicating position of a communicating passage to the hollow chamber on a pump main body, so as to drain outward the surplus portion of oil charged into the hollow chamber. CONSTITUTION:When oil is discharged to a discharge port 24 by rotation of a cylinder block 19 and let flow through a discharge passage 26, a control valve 48 is received the oil an its ball valve body 50 and opened by application of force due to oil pressure, delaying from the beginning of discharge by rotation of the cylinder block 19, nextly, changed over to be closed. During the period, a portion of oil flowing through the discharge passage 26 is charged into a hollow chamber 17A through a primary side flow passage 44B and a communicating passage 46, and oil can be automatically charged to the hollow chamber 17A accompanied with rotation of the cylinder block 19. Further, a drain passage 53 to drain surplus portion of oil is communicated to the hollow chamber 17A on the position above the communicated position of the communicating passage 46 to the hollow chamber 17A. Hereby, a swash plate type variable displacement piston pump of excellent handling property is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic pump that sucks in and discharges oil by operating a pump means.

[Conventional technology]

Conventionally, a typical configuration of this type of hydraulic pump is as shown in FIG. 4, in which a pump body 3 is provided with one end opening side of the body member 1 closed by a lid member 2 to form a cavity 3A inside.
A cylinder block 5 housed in a cavity 3A in a pump body 3 and rotated by a drive shaft 4 is provided in a slidable manner to a valve plate 6 fixedly attached to a lid member 2, and the cylinder block 5 is in sliding contact with the valve. A suction port 8 communicating with the suction passage 7 and a discharge port 10 communicating with the discharge passage 9 are opened on the sliding surface of the plate 6, and a plurality of piston holes 5A are provided through the cylinder block 5.
Insert the piston 11 so that it can slide back and forth, and the piston 1
A swash plate 14 is rotatably supported on the pump body 3 so that the amount of reciprocating sliding of the piston 11 can be changed freely, and as the shilling block 5 rotates, the amount of reciprocating sliding of the piston 11 is regulated by the swash plate 14, and the piston 11 is reciprocated in the axial direction. The oil is sucked through the suction passage 7 and then transferred to the discharge passage 9.
The pump means is provided so as to discharge the liquid to the pump.

Then, before operating this pump means, the pump body 3
Remove the oil filler plug 13 screwed into the oil filler port 12 provided in the pump body 3, and inject the same type of oil as the oil to be sucked and discharged into the empty chamber 3A in the pump body 3. Seizing is prevented by providing a lubricating effect at the sliding contact points and the sliding contact points between the cylinder block 5 and the piston 11. Then, the excess oil in the empty chamber 3A is discharged to the outside through the discharge path 3B.

[Problem that the invention seeks to solve]

However, if you forget to inject oil into the empty chamber 3A in the pump body 3 and operate the pump means, a seizure phenomenon will occur at the sliding contact points of the pump means, damaging the hydraulic pump itself. It is necessary to check whether oil has been injected into the empty chamber 3A before operation, and there is a problem in that it is very troublesome to handle.

The present invention solves this problem, and provides a hydraulic pump that automatically injects oil into a cavity within the pump body as the pumping means operates, and is easy to handle.

[Means for solving problems]

For this reason, the present invention provides a pump body in which a lid member is fixed to the main body member so as to close one end opening side of the main body member, which has a hollow interior formed by recessing one end surface, thereby forming a hollow chamber inside. A pump means having a sliding contact point is provided in the empty space of the pump body so as to be able to operate freely so as to draw in and discharge oil, and a discharge flow path through which oil discharged by the operation of the pump means and this discharge flow path are provided. providing a communication path in the lid member that branches from the flow path and communicates with the empty chamber at a position above the sliding contact point of the pump means;
A control valve having an open position for opening the communication passage and a closed position for closing the communication passage is disposed in the communication passage provided in the lid member, and when the pump means is activated, the control valve is switched from the open position to the closed position after the start of the operation. It is provided so that it can be operated freely and the oil flowing through the discharge flow path can be freely injected into the empty chamber from the communication path during switching operation from the open position to the closed position, and the excess oil injected into the empty chamber is discharged to the outside. A discharge passage is provided in the pump body in communication with the cavity at a position above the position where the communication passage communicates with the cavity.

[For production]

In this configuration, when the pump means is operated, oil is sucked and discharged, and while the control valve is switched from the open position to the closed position after the start of the operation, the oil flowing through the discharge passage is transferred from the communication passage to the inside of the pump body. The oil is injected into the cavity and lubricates the sliding contact points of the pump means. When the control valve is in the closed position, the communication passage is closed and the oil flowing through the discharge passage is no longer injected into the empty chamber. Therefore, oil can be automatically injected into the empty space within the pump body as the pump means operates, and a hydraulic pump with excellent handling properties can be obtained.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a case in which the present invention is applied to a swash plate type variable displacement piston pump, and 15 is a main body member, one end surface of which is recessed to form a hollow interior. 16 is a lid member, and the main body member 15
A pump main body 17 is fixed to the main body member 15 by a tightening bolt (not shown) so as to close one end opening side of the pump main body 17, and has a cavity 17A inside. Reference numeral 18 denotes a drive shaft, which is rotatably supported by the pump body 17 and has one end connected to the pump body 17.
It is provided so as to protrude from the outside. Reference numeral 19 denotes a cylinder block, which is integrally connected to the drive shaft 18 via a spline portion 20 and rotatably housed in the cavity 17A. 21
are a plurality of piston holes in the cylinder block 19,
They extend axially through the cylinder block 19 at equal intervals on its circumference around the axis of the cylinder block 19. Reference numeral 22 denotes a valve plate, which is fixed to the lid member 16 so as to be able to freely come into sliding contact with one end surface of the cylinder block 19 where the piston hole 21 opens. Reference numeral 23 indicates an oil suction port, and 24 indicates an oil discharge port, which are respectively provided through the valve plate 22 in the axial direction and open to the sliding surface of the valve plate 22 on which the cylinder block 19 slides. A plurality of piston holes 21 are formed facing each other on a circumference having the same diameter as the circumference through which the piston holes 21 are penetrated so that the piston holes 21 communicate with each other alternately. 25 is a suction flow path, and 26 is a discharge flow path, which are provided in the lid member 16 and communicated with the suction port 23 and the discharge port 24. A piston 27 is fitted into each piston hole 27 of the cylinder block 19 so as to be able to reciprocate and slide, and has a shoe 28 pivotally supported at its tip which discharges from the other end surface of the cylinder block 19. 29 is a swash plate, which is housed in the empty chamber 17A so as to be freely tiltable within a certain tilt angle range, and comes into contact with a shoe 28 provided at the tip of the piston 27 to restrict the reciprocating sliding of the piston 27. The reciprocating sliding amount of the piston 27 can be freely changed by changing the tilting angle. The cylinder block 19, valve plate 22, piston 27, and swash plate 29 constitute a pump means. Reference numeral 30 denotes a pressing piston, which is fitted into a guide member 31 protruding from the lid member 16 into the empty chamber 17A so as to be able to reciprocate in the axial direction, and is forced by the force of a spring 32 to force the flow from the discharge passage 26 to the action chamber 33 formed on the back surface. It is provided in contact with the swash plate 29 so that the tilting angle of the swash plate 29 is maximized by the acting force based on the pressure of the oil introduced through the passage 34. Reference numeral 35 denotes an operation piston, which is inserted into a guide member 36 protruding from the lid member 16 into the empty chamber 17A so as to be able to reciprocate and slide freely in the axial direction.
The tip of the piston 3 is in contact with the swash plate 29 so as to press the swash plate 29, and an action chamber 37 is formed on the back side. , is provided in contact with the back surface of the operating piston 35 so as to be freely movable forward and backward in the axial direction. Reference numeral 39 designates a pressure control valve, in which a valve body 39A is attached to the lid member 16, and a valve body 41 pressed by a force of a spring 40 is slidably inserted in the axial direction into a valve hole 39B provided inside the valve body 39A. ing.

In addition, the valve body 39A is provided with a primary side flow path 44A, a secondary side flow path 42A, and a discharge flow path 43A that are open to the mounting surface to the lid member 16 and communicate with the valve hole 39B at intervals in the axial direction. ing. The lid member 16 includes a primary flow path 44B that branches from the discharge flow path 26 and communicates with the primary flow path 44A, and a secondary flow path 42 that communicates between the action chamber 37 and the secondary flow path 42A.
B. A discharge passage 43B is provided which communicates between the empty chamber 17A and the discharge passage 43A. The pressure control valve 39 is connected to the primary flow path 44
When the pressure of the oil in the discharge passage 26 acting on the valve body 41 via A and 44B does not reach the set pressure based on the force of the spring 40, the valve body 41 is in the position shown in FIG. 42A is communicated with the discharge flow path 43A, and when the set pressure is reached, the valve body 41 slides to the left in FIG. It is supposed to be done. Reference numeral 46 denotes a communication passage, which is provided in the lid member 16 so as to connect to the primary side passage 44B branched from the discharge passage 26 and communicate with the empty chamber 17A, and a discharge passage 53, which will be described in detail later, is located above the pump means. With the swash plate type variable displacement piston pump installed as shown in Figure 1, the empty chamber 17. The cylinder block 19 and valve plate 2 constituting the pump means communicate with A.
2 and (q) above the sliding contact point between the cylinder block 19 and the piston 27. A plug member 47 is provided on the lid member 16 to close the opening of the communication path 46 to the outside.

Reference numeral 48 denotes a control valve, which is disposed in the communication passage 46 and includes a valve seat 51, a ball valve body 50 that is pressed in the unseating direction from the valve seat 51 by the force of a spring 49, and a control valve 50 that is pressed in the unseating direction from the valve seat 51 by the force of a spring 49. The ball valve body 50 is arranged at a distance from the valve seat 51 in the axial direction so as to regulate the amount of movement, and the ball valve body 50 is in the open position where the opening passage 46 is opened until the ball valve body 50 is moved from the valve seat 51 until it is seated on the valve seat 51. It has a closed position in which the communication path 46 is closed when the user is seated thereon.

The control valve 48 receives the oil discharged by the rotation of the cylinder block 190 on the ball valve element 50, and the ball valve element 50 moves from the open position due to the acting force based on the pressure of the oil later than the start of discharge due to the rotation of the lock 19. It is provided so that it can be switched freely to the closed position. Discharge (10) When the swash plate type variable displacement piston pump as described above is installed in the state shown in FIG. It is provided in the member 15 and is connected to an external storage tank (not shown) via piping, so that the excess oil injected into the empty chamber 17A and filled therein is discharged to the outside.

Next, the operation of this configuration will be explained.

FIG. 1 shows the state of the swash plate type variable displacement piston pump after it has been installed.
0 to maximize the tilting angle, and the pressure control valve 39 has the valve body 41 in the position shown in FIG. 44A
I am blocking it.

Further, in the control valve 48, the ball valve body 50 contacts the regulating member 52 by the force of the spring 49, thereby closing the communication passage 46. When the cylinder block 19 is rotated by the drive shaft 18, the piston 27 is reciprocated in the axial direction along the swash plate 29 with the maximum tilt angle with the maximum reciprocating sliding amount, and the piston 27 is reciprocated in the axial direction through the suction flow path 25 ) The oil sucked in from the suction port 23 is discharged to the discharge port 24 to obtain the maximum discharge amount. The control valve 48 is connected to the discharge port 24
The oil discharged to the primary side flow path 44 and flowing through the discharge flow path 26
It acts on the ball valve body 50 through the B1 communication passage 46, and the ball valve body 50 is moved to the closed position against the force of the spring 49 by the acting force based on the oil pressure after the start of discharge due to the rotation of the cylinder block 19. During this switching operation, some of the oil flowing through the discharge flow path 26 flows through the primary flow path 44B.
, is injected into the cavity 17A through the communication passage 46 to lubricate the sliding contact points between the cylinder block 19 and the valve plate 22 and the sliding contact points between the cylinder block 19 and the piston 27. Then, the pressure of the oil flowing through the discharge flow path 26 is adjusted to the pressure control valve 39.
When the set pressure of the pressure control valve 39 is reached, the valve body 41 of the pressure control valve 39 slides to the left in FIG.
4A and is cut off from the discharge flow path 43A, and a part of the oil in the discharge flow path 26 enters the operating piston 350 and the action chamber 37 α2) Primary flow paths 44B, 44A, and secondary flow paths 42A 142B
The operating piston 35 slides to the left in FIG. 1 due to the action force based on the pressure of the oil introduced into the action chamber 37, reducing the tilt angle of the swash plate 29 and increasing the amount of oil discharged. This prevents the oil pressure in the discharge passage 26 from increasing beyond the set pressure of the pressure control valve 39. When the oil pressure in the discharge flow path 26 becomes lower than the set pressure of the pressure control valve 39 due to a decrease in the discharge amount, the valve body 41 of the pressure control valve 39 slides back to the state shown in FIG. The oil in the chamber 37 is discharged to the empty chamber 17A via the secondary flow paths 42B, 42A and the discharge flow paths 43A, 43B, and the swash plate 29
When pressed at 0, the tilting angle increases and the amount of oil discharged increases. Then, when the rotation of the cylinder block 19 is stopped, oil is no longer discharged. The control valve 48 is a ball valve body 50
When the force based on the oil pressure acting on the ball valve body 50 becomes lower than the force of the spring 49, the ball valve body 50 returns to the state shown in FIG. 1 and closes the communication passage 46.

In this operation, when oil is discharged to the discharge port 24 and flows through the discharge passage 26 due to the rotation of the cylinder block 19 (13), the control valve 48 receives the oil on the ball valve body 50 and the ball valve body 50 receives the oil. is discharged due to the rotation of the cylinder block 19, and after the start of the discharge, it moves from the regulating member 52 against the force of the spring 49 due to the acting force based on the oil pressure and reaches the open position, and then the ball valve body 50 is placed in the valve seat 51. Since the control valve 48 is switched from the open position to the closed position after being seated, a portion of the oil flowing through the discharge passage 26 is drained through the primary side passage 44B1 and the communication passage 46. Since oil is injected into the chamber 17A, oil can be automatically injected into the empty chamber 17A as the cylinder block 19 rotates, and a swash plate type variable displacement piston pump with excellent handling properties can be obtained. In addition, since the communication passage 46 communicates with the empty chamber 17A at a position above the sliding contact point between the cylinder block 19 and the valve plate 22 and the sliding contact point between the cylinder block 19 and the piston 27, the swash plate type variable displacement piston When the cylinder block 19 is first rotated to suck and discharge oil after the pump is assembled, oil is injected into the empty space 17A via the α-perfusion passage 46, although the empty chamber 17A is not filled with oil. Oil flows efficiently to each of the sliding contact points, and a good lubrication effect can be obtained. Furthermore, since the discharge path 53 for discharging the excess oil injected into the empty chamber 17A is connected to the empty chamber 17A at a position above the position where the communication path 46 communicates with the empty chamber 17A,
After the swash plate type variable displacement piston pump is assembled, when oil is first sucked and discharged as described above, the air present in the suction passage 25, the piston hole 21 of the cylinder block 19, etc. gets mixed with the oil, and the empty chamber 17A is mixed with the oil. Even if the air flows into the chamber 17A, the air is separated from the oil and can be quickly discharged using the discharge passage 53, without impeding the injection of oil into the empty chamber 17A. Moreover, oil is injected into the empty chamber 17A via the control valve 48 which is switched from the open position to the closed position each time the pump means starts operating, and the surplus of the injected oil is discharged from the discharge passage 53. By setting the switching operation time of the control valve 48 from the open position to the closed position to an optimal value according to the required amount of oil to be injected into the vacant chamber 17A, the oil in the vacant chamber 17A can be replaced well, and the oil By preventing the deterioration of α9, it is possible to obtain better lubricating action of the pump means.

In one embodiment, the control valve 48 was provided so as to close the communicating passage 46 when the ball valve element 50 was in contact with the regulating member 52, but when the ball valve element was in contact with the regulating member, the communicating passage 46 was closed. It may be provided so that it opens. Further, although the swash plate type variable displacement piston pump is used, a fixed displacement type or oblique shaft type hydraulic pump may also be used.

FIG. 2 shows another embodiment of the present invention, and only the points different from the first embodiment will be explained.

The control valve 48A disposed in the communication path 46A includes a spool valve body 50A that is pressed downward in FIG. It has an open position where the communication passage 46A is opened and a closed position where the spool valve body 50A moves to the upper position and closes the communication passage 46A. Then, a passage 54 is provided which branches from the discharge passage 26 and connects to the control valve 48A so that the acting force based on the pressure of the oil flowing through the discharge passage 26 acts on the spool valve body 50A against the force of the spring 49A. A variable throttle valve 55 is disposed in the passage 5α6) 4 so that the opening degree of the passage 54 can be adjusted. Therefore, the control valve 48A receives the oil discharged by the rotation of the cylinder block 190 from the passage 54 onto the spool valve body 50A, and the spool valve body 50A acts based on the pressure of the oil later than the start of discharge due to the rotation of the cylinder block 19. The force causes the spring 49A to move from the position shown in FIG. The switching operation time to the closed position can be adjusted freely.

FIG. 3 shows still another embodiment of the present invention, and only the points different from the first embodiment will be described.

The control valve 48B disposed in the communication path 46B is held in an open position by the force of a spring 49B, and can be switched to a closed position by energization. Then, when the operation switch 57 is closed and the electric motor 56 connected to the drive shaft 18 is energized to rotate the cylinder block 19, the control valve 48B is activated by the timer switch 58.
As a result, the electric motor 56 is energized later than the start of energization, and can be switched from the open position to the closed position. During the switching operation from the open position to the closed position, the oil flowing through the discharge passage 26 is transferred to the communication passage 46B.
This makes it possible to freely inject into the empty chamber 17A.

By adjusting the time setting of the timer switch 580, the switching operation time of the control valve 48B from the open position to the closed position can be freely adjusted.

〔Effect of the invention〕

As described above, the present invention provides a pump body in which a lid member is fixed to the main body member so as to close one end opening side of the main body member, which has a hollow interior formed by recessing one end surface, thereby forming a hollow chamber inside. and a pump means having a sliding contact point is housed in the empty space in the pump body so as to be operable to suck and discharge oil,
The lid member is provided with a discharge passage through which oil discharged by the operation of the pump means flows, and a communication passage that branches from the discharge passage and communicates with the empty chamber at a position above the sliding contact portion of the pump means, A control valve having an open position and a closed position for closing the communication passage is disposed in the communication passage provided, and when the pump means is activated, the control valve can be switched from the open position to the closed position after the start of the operation. 08) is provided so that oil flowing through the discharge flow path can be freely injected into the empty chamber from the communication path during switching operation from the open position to the closed position, and excess oil injected into the empty chamber is discharged to the outside. By providing a discharge path in the pump body that communicates with the vacant chamber at a position above the communication position of the communication passage to the vacant chamber, oil is automatically injected into the vacant chamber in the pump body as the pump means operates. This makes it possible to obtain a hydraulic pump with excellent handling properties.

In addition, since the communicating passage communicates with the empty chamber at a position above the sliding contact point of the pump means, the oil injected into the empty chamber through the communicating path efficiently flows to the sliding contact point, resulting in good lubrication. can be obtained. Furthermore, since the discharge path for discharging excess oil injected into the empty chamber is connected to the empty chamber at a position above the position where the communication passage communicates with the empty chamber, the oil is When inhaling and discharging oil, even if air that exists in the oil suction channel or inside the pump means mixes with the oil and flows into the empty chamber, the air is separated from the oil and quickly utilized the discharge channel. This allows oil to be discharged without obstructing the injection of oil into the empty space.

α9) Furthermore, oil is injected into the empty chamber via the control valve which switches from the open position to the closed position each time the pump means starts operating, and at the same time discharges the surplus of the injected oil from the discharge path. By setting the switching operation time of the valve from the open position to the closed position to the optimum value according to the required amount of oil to be injected into the vacant chamber, the oil in the vacant chamber can be replaced effectively and oil deterioration can be prevented. This has the effect of making it possible to obtain better lubricating action for the pump means.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a swash plate variable displacement piston pump as a hydraulic pump showing one embodiment of the present invention, and FIG. 2 is a swash plate variable displacement piston pump showing another embodiment of the present invention. 3 is a longitudinal sectional view of a swash plate type variable displacement piston pump showing still another embodiment of the present invention,
FIG. 4 is a longitudinal sectional view of a conventional swash plate type variable displacement piston pump. 15-m-main body member, 16--lid member, 17 pump main body, 17A-m-empty chamber, 26--discharge channel, (20) 46, 6A1 6B series passage, 48, 8A1 8B-control valve , 3- Exhaust channel.

Claims (1)

[Claims] A pump body is provided in which a lid member is fixed to the main body member so as to close one end opening side of the main body member, which has a hollow interior formed by recessing one end surface, thereby forming a hollow space inside the pump body. is provided with a pump means having a sliding contact point so as to be able to operate freely so as to draw in and discharge oil, and a discharge channel through which oil discharged by the operation of the pump means flows, and a pump branched from this discharge channel. A communication passage communicating with the empty chamber is provided in the lid member at a position above the sliding contact point of the means, and a control valve having an open position for opening the communication passage and a closed position for closing the communication passage is disposed in the communication passage provided in the lid member. The control valve is provided to be able to switch from the open position to the closed position after the start of the pump operation when the pump means is activated, so that the oil flowing through the discharge passage is emptied from the communication passage while the pump means is being switched from the open position to the closed position. A discharge passage is provided in the pump body, communicating with the vacant chamber at a position above the communicating passage to the vacant chamber, so that excess oil injected into the vacant chamber can be discharged to the outside. Consists of hydraulic pump.