JP2000145618A - Axial plunger pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power loss by eliminating innecessary discharging, and prevent heating due to increase of a flow rate of drain. SOLUTION: A plurality of spill pins 35 are retreatably projected on a cylinder block 15 at its more radially inner portion than a plunger 23, for forcibly opening a suction check valve 28 due to pushing operation. A control swash plate 36 faced to end faces of the spill pins 35 is attached to a center portion of an end face of a driving swash plate 16, slidably in an axial direction, and in a locked state in a rotating direction. The axial position of the control swash plate 36 is operated by a solenoid valve 44. When the control swash plate 36 is separated from the spill pins 35, actual discharging is operated in a total area of discharge processes of the plungers 23. When the control swash plate 36 is displaced to a position to be brought into contact with the spill pins 35, the actual discharging is suspended due to operation of pushing and opening the suction check valve 28 by the spill pins 35, even under the discharge process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial plunger pump used for an engine fuel pressurizing pump and the like, and more particularly to an axial plunger pump improved to reduce power loss.

[0002]

2. Description of the Related Art An axial plunger pump used for a fuel pressurizing pump of an engine is disclosed in Japanese Patent Application Laid-Open No. 9-11 / 1991.
A device such as that shown in Japanese Patent No. 2408 has been conventionally devised.

[0003] In this axial plunger pump, a cylinder block for accommodating a plurality of plungers so as to be able to advance and retreat in the axial direction is disposed to face a swash plate that is driven to rotate, and each plunger is sequentially pressed against the swash plate. The projection and the retraction are repeated in the cylinder chamber. And
Each cylinder chamber of the cylinder block is individually connected to the suction passage and the discharge passage via a suction check valve and a discharge check valve, and when the plunger protrudes, the corresponding suction check valve is opened to suck into the cylinder chamber. When the plunger is retracted, the hydraulic fluid is discharged by opening a corresponding discharge check valve.

[0004]

However, in this conventional axial plunger pump, since the capacity of each cylinder chamber is constant, the flow rate of the hydraulic fluid discharged from the pump is substantially proportional to the rotation speed of the swash plate. When an engine or the like having a large fluctuation in rotational speed is used as a power source, a surplus of hydraulic fluid must be drained from the discharge passage, which increases the power loss of the system and generates heat in the drain portion. And the like.

[0005] In particular, when this conventional axial plunger pump is used as a fuel pressurizing pump for an engine,
Since the capacity of each cylinder chamber is determined so that sufficient fuel can be supplied when the engine is fully opened and when cold starts, during normal engine operation, most of the fuel discharged from the cylinder chamber is pressure-controlled. Drainage from the valve to the pump suction side not only increases the power loss of the engine and deteriorates fuel efficiency, but also generates heat near the pressure control valve, and the heat tends to generate vapor.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an axial plunger pump capable of reliably reducing power loss by eliminating unnecessary discharge of hydraulic fluid and preventing heat generation at a drain portion. .

[0007]

As a means for solving the above-mentioned problems, the invention according to the first aspect is characterized in that a cylinder block for accommodating a plurality of plungers so as to be able to advance and retreat in the axial direction is driven by a rotary drive. Each plunger is sequentially pressed by the driving swash plate to repeatedly project and retreat in the cylinder chamber, and the corresponding individual suction check valve is opened and sucked into the cylinder chamber. In an axial plunger pump for discharging a liquid by also opening a corresponding discharge check valve, the suction check valve is pushed into an end face of the drive block of the cylinder block on the swash plate side radially inside the plunger. A plurality of spill pins are forcibly pushed open and protruded so as to be able to advance and retreat. The control swash plate slidably in the axial direction that,
The control swash plate is mounted while being locked in the rotation direction, and furthermore, an advance / retreat operating mechanism is provided to advance / retreat the control swash plate to an arbitrary axial position.

In the case of the present invention, when the control swash plate is displaced in a direction away from the spill pin by the advance / retreat operation mechanism,
When the drive swash plate rotates, the control swash plate no longer presses the spill pin, and in each cylinder chamber, the suction check valve is opened when the plunger protrudes, and almost all of the sucked hydraulic fluid is discharged when the plunger is retracted. It will open and discharge. Further, when the control swash plate is displaced in the direction approaching the spill pin by the advance / retreat operation mechanism, the control swash plate presses the spill pin, and the suction check valve is forcibly opened at the time of the plunger retreat operation. Therefore, even when the plunger is retracted, the discharge check valve is not opened while the suction check valve is open, and the substantial discharge of the working fluid is not performed during that time. The area where the actual discharge is performed in each cylinder chamber is determined according to the axial position of the control swash plate adjusted by the advance / retreat operating mechanism.

According to a second aspect of the present invention, in the first aspect of the present invention, the forward / backward operating mechanism is constituted by an electromagnetic actuator, and the control swash plate is directly advanced / retracted by the power of the electromagnetic actuator. . In this case, the control swash plate is moved forward and backward by the electromagnetic actuator with good responsiveness.

According to a third aspect of the present invention, in the first aspect of the present invention, the power of the reciprocating operation mechanism is obtained by processing the feed pressure of the hydraulic fluid introduced into the suction passage. In this case, the electric loss is reduced as compared with the case where the operation force on the control swash plate is directly obtained by the power of the electromagnetic actuator, and the power (discharge pressure) of the pump is used to operate the advance / retreat operation mechanism. The power loss of the pump is also reduced.

According to a fourth aspect of the present invention, in the first aspect of the invention, the power of the forward / backward operation mechanism is obtained by processing the pressure of the hydraulic fluid in the discharge passage. In this case, the electric loss is reduced as compared with the case where the operation force on the control swash plate is directly obtained by the power of the electromagnetic actuator, and since the pressure of the high-pressure discharge passage is used, the pressure of the advance / retreat operation mechanism is reduced. The area of the part can be reduced.

According to a fifth aspect of the present invention, the pump according to any one of the first to fourth aspects is used as a fuel pressurizing pump for an engine. In this case, unnecessary fuel discharge can be eliminated, so that the power loss of the engine is reduced and the drain flow rate of the fuel from the discharge passage is also reduced.

According to a sixth aspect of the present invention, in accordance with the fifth aspect of the present invention, an engine load sensor for detecting a load state of the engine, and a signal received from the engine load sensor is received, and the control swash plate responds to the engine load. And a controller for controlling the advance / retreat operation mechanism so as to be displaced to the inclined position. In this case, when a signal from the engine load sensor is input to the controller, the advance / retreat operation mechanism is controlled by the controller, and the control swash plate is displaced to a position corresponding to the engine load. Is supplied to the engine.

According to a seventh aspect of the present invention, in accordance with the fifth or sixth aspect of the present invention, an engine start sensor for detecting the start of the engine, and a control swash plate receiving the detection signal of the engine start sensor is connected to the spill pin. And a controller for controlling the advance / retreat operating mechanism so as to be displaced to a predetermined position where it comes into contact. In the case of the present invention, when the start of the engine is detected by the engine start sensor,
The control swash plate is displaced to a predetermined position in contact with the spill pin by the control of the advance / retreat operating mechanism by the controller, so that the suction check valve is forcibly opened by the spill pin when the plunger retreats, and as a result, when the engine is started. The pump load is reduced, and the pump can be started smoothly.

The invention according to claim 8 is the invention according to any one of claims 5 to 7, wherein an engine start sensor for detecting start of the engine, a temperature sensor for detecting the ambient temperature of the engine, and the engine. A controller that receives the signal of the start sensor and the signal of the temperature sensor, and controls the advance / retreat operation mechanism so that the control swash plate is displaced to a position away from the spill pin when the engine is started under the condition of the set temperature or less. I did it. In this case, when the controller judges that the cold start is the cold start by receiving the signal of the engine start sensor and the signal of the temperature sensor, the control swash plate is displaced to a position separated from the spill pin by the control of the advance / retreat operating mechanism by the controller, and as a result, Almost all of the fuel sucked into the cylinder chamber is discharged by opening the discharge check valve. Therefore, it is possible to supply a sufficient flow rate of fuel during cold start.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention shown in FIGS. 1 to 4 will be described.

In this embodiment, an axial plunger pump according to the present invention is applied to a fuel pressurizing pump 1 of an engine. The fuel supply system of this engine is shown in FIG.
As shown in FIG. 1, after the fuel sent from the fuel tank 3 via the motor-driven feed pump 2 is regulated to a predetermined pressure by the low-pressure regulator 4, the fuel is pressurized to a high pressure by the fuel pressurizing pump 1. This is a basic configuration for supplying the fuel to the injector 6 of the fuel injection device.

Pump housing 7 of fuel pressurizing pump 1
Is formed by bolting a bearing block 13 to a pump body 12 having a suction port 10 (see FIG. 2) and a discharge port 11.
3 in the working chamber 14 formed between the cylinder blocks 1
The main pump components such as the pump 5 and the drive swash plate 16 are accommodated. The drive shaft 17 is fitted into the bearing block 13, and in this state, the drive shaft 17 is supported by the bearing block 13 via the metal bearing 18. The drive swash plate 16 having an end face inclined at a predetermined angle with respect to the axis is integrally formed at an end of the drive shaft 17 facing the inside of the working chamber 14, and the other end of the drive shaft 17 is provided with an engine. A coupling 19 for coupling with a camshaft (not shown) is provided. The suction port 10 communicates with the working chamber 14 so that the entire amount of fuel sent from the low-pressure regulator 4 into the pump housing 7 once flows into the working chamber 14.

The cylinder block 15 is formed of a material having high wear resistance separately from the pump body 12, and is connected to the bottom wall of the pump body 12 by bolts 20. The cylinder block 15 has three cylinder holes 21 (cylinder chambers) formed in the axial direction at equal intervals in the circumferential direction. Each of the cylinder holes 21 is biased by a spring 22 in the direction of the drive swash plate 16. The bottomed cylindrical plunger 23 is housed so as to be able to advance and retreat. Each plunger 23 has a hemispherical concave portion 24 formed on the top surface thereof, and a shoe 25 whose end surface is in sliding contact with the drive swash plate 16 is slidably fitted and held in the concave portion 24. Accordingly, when the drive swash plate 16 rotates, each plunger 23 is sequentially pressed by the drive swash plate 16 via the shoe 25, and continuously advances and retreats in cooperation with the spring 22. A ball bearing 26 is interposed between the bottom wall of the bearing block 13 and the driving swash plate 16, and the thrust load acting on the driving swash plate 16 is supported by the bearing block 13 via the ball bearing 26. It has become.

In the cylinder block 15, three suction passages 27 of the same shape which communicate the bottom (the pump body 12 side) of each cylinder hole 21 and the working chamber 14 are formed at equal intervals in the circumferential direction. An intake check valve 28 that allows only the flow of fuel in the direction of the cylinder hole 21 is interposed in the intake passage 27. Each suction passage 27 has an axial hole 29 formed radially inward of the corresponding cylinder hole 21 on the cylinder block 15, an intermediate position between the axial hole 29 and the outer peripheral surface of the cylinder block 15 (the working chamber). 14) and a passage groove 31 formed on the overlapping surface of the cylinder block 15 and the pump body 12 to connect the axial hole 29 and the cylinder hole 21 (FIG. 3).
reference. ), And the suction check valve 28 is disposed at a connecting portion between the axial hole 29 and the passage groove 31. The suction check valve 28 has a valve seat 32 formed at an end of the axial hole 29 on the pump body 12 side.
A valve body 34 urged by a spring 33 from the second side comes into close contact with the valve seat 32.

The pump body 12 of each axial hole 29
A spill pin 35 having a reduced diameter portion 35a at its tip is slidably fitted to the end opposite to the end. The spill pin 35 comes into contact with the valve body 34 of the suction check valve 28 at the tip end of the reduced diameter portion 35a, and forcibly pushes the valve body 34 open when pushed from the end face side of the cylinder block 15. I have. The base of the spill pin 35 projects a predetermined amount from the end face of the cylinder block 15 toward the drive shaft 17 when the valve body 34 of the suction check valve 28 is closed.

Further, as shown in FIG. 2, the pump body 12 is formed with three discharge passages 8 connecting the bottom of each cylinder hole 21 and the discharge port 11, and in the middle of each discharge passage 8. Is provided with a discharge check valve 9 that allows only the flow of fuel in the discharge direction.

On the other hand, a control swash plate 36 facing the base end surface of the spill pin 35 is attached to the center of the end surface of the driving swash plate 16 so as to be slidable in the axial direction and locked in the rotating direction. Have been. Specifically, the control swash plate 36 is a swash plate main body 3 having an inclined surface facing the end surface of the spill pin 35.
7 and a shaft portion 39 that is slidably fitted in the center hole 38 of the drive swash plate 16. A cutout groove 40 is formed in the outer peripheral surface of the shaft portion 39 along the axial direction. And the shaft 39
When the pin 41 supported by the driving swash plate 16 is engaged with the notch groove 40 in a state where is fitted in the center hole 38, the relative rotation between the driving swash plate 16 and the control swash plate 36 is restricted. ing. A return spring 42 is interposed between the shaft 39 and the bottom of the center hole 38, and the control swash plate 36 is urged toward the spill pin 35 by the spring 42.

Here, the control swash plate 36 is set so as to be completely out of contact with all the spill pins 35 at the maximum retreat, and to simultaneously contact all the spill pins 35 at the maximum protrusion. Therefore, when the control swash plate 36 is retracted to the maximum, the spill pin 35 is not pushed at all. On the other hand, when the control swash plate 36 is projected to the maximum, all the spill pins 35 are pushed and all the suction check valves are pushed. Push and hold 28 open. Also,
The drive swash plate 16 and the control swash plate 36 are, as shown in FIG. 4, the phase of the displacement of the end face of the drive swash plate 16 at an arbitrary plunger (23) position and the position of the spill pin (35) corresponding to the plunger 23. Are positioned in the rotation direction such that the phase of the displacement of the end face of the control swash plate 36 is offset by 180 °.

The phase of the displacement of the end face of the control swash plate 36 depends on the displacement of the control swash plate 36 in the axial direction.
However, in the area between E and F where the control swash plate 36 and the spill pin 35 abut (the area where the suction check valve 28 is pushed open by the spill pin 35), the control swash plate 36 protrudes to the maximum. It is configured to decrease continuously as the phase of C changes from the phase of C to the phase of D when it retreats to the maximum. Therefore, the region between E and G where the discharge is substantially performed in the discharge process of the plunger 23 changes continuously according to the axial displacement of the control swash plate 36.

A push rod 43 for pressing the center of the end face of the control swash plate 36 is supported through the center of the cylinder block 15 and the pump body 12 so as to be axially displaceable. Is moved forward and backward by a solenoid valve 44 (forward and backward operation mechanism, electromagnetic actuator in the present invention) attached to the pump body 12. The solenoid valve 44 includes a plunger 45 that directly presses the push rod 43, a spring 46 that urges the plunger 45 in a protruding direction, and a solenoid 47 that magnetically attracts the plunger 45. The substantial biasing force of the spring 46 is appropriately adjusted according to the exciting current, so that the axial displacement of the control swash plate 36 can be arbitrarily operated. The biasing force of the spring 46 is set to be larger than the biasing force of the return spring 42 on the control swash plate 36 side, and the control swash plate 36 is retracted to the maximum with respect to the spill pin 35 when the solenoid 47 is not excited. Has become.

The solenoid valve 44 is controlled by a controller 48. The controller 48 includes an engine load sensor 49 such as a throttle sensor for detecting the engine load, an engine start sensor 50 for detecting the start of the engine, and A temperature sensor 51 for detecting the ambient temperature of the engine is electrically connected, and signals from these sensors 49, 50, 51 are taken in as input signals.

The controller 48 receives the signal from the engine load sensor 49 so that the control swash plate 36 is displaced to an axial position corresponding to the engine load (so that a substantial discharge according to the engine load is obtained). ) The basic control configuration for controlling the output current of the solenoid valve 44 is provided.
In this basic control, the controller 48
When a start detection signal is input from the engine start sensor 50, the output current of the solenoid valve 44 is controlled so that the control swash plate 36 is displaced to a predetermined position for pressing the spill bin 35. The control of the solenoid valve 44 at the time of starting the engine is performed at the moment when the pump is started.
In order to reduce the excessive load acting on the engine, it is performed for a very short time at the moment of starting the engine.

When the engine is started, the control of the control swash plate 36 is basically performed as described above. At this time, the controller 48 controls the engine ambient temperature to be equal to or lower than the set temperature based on the signal of the temperature sensor 51. If it is determined that the engine is cold or cold, the output current of the solenoid valve 44 is controlled so that the control swash plate 36 is retracted to the maximum. Therefore, at the start of the cold sensation, substantial discharge is performed in the entire discharge region, and a sufficient flow rate of fuel is supplied to the engine. The control at the start of the cold sensation by the controller 48 may reduce the substantial discharge of the fuel only for a short period of time at the beginning of the engine start, and thereafter may switch the substantial discharge to the maximum.

Since the fuel pressurizing pump 1 is configured as described above, the position of the control swash plate 36 is set so that the control swash plate 36 is retracted to the maximum at the start of cold sensation or at the time of full-open operation (when the engine load is maximized). The swash plate 36 and each spill pin 35 are controlled.
Are kept in a non-contact state, each plunger 23 is sequentially pressed by the drive swash plate 16. At this time, since the suction check valve 28 is not forcibly pushed and opened by the spill pin 35, the suction check 28 valve is opened when the plunger 23 projects, and almost all of the fuel sucked into the cylinder hole 21 continues. When the plunger 23 moves backward, the discharge check valve 9 is opened and the plunger 23 is sent out to the discharge passage 8.

During normal operation, the position of the control swash plate 36 is controlled in accordance with the engine load, and the control swash plate 36 presses the spill pin 35 as the drive swash plate 36 rotates. At this time, the driving swash plate 1 pressing the plunger 23
Since the phase of the displacement of the end face of the control swash plate 36 and the phase of the displacement of the end face of the control swash plate 36 pressing the spill pin 35 are set to be offset by 180 °, as shown in FIG. The suction check valve 28 is forcibly opened in a region between the two, and the suction check valve 28 is closed in a region between E and G at a later stage of the discharge process. Since the region between E and G where the discharge is substantially performed at this time changes according to the engine load, the fuel at a flow rate corresponding to the engine load is supplied to the injector 6 of the engine.

Further, at the time of normal engine start not at the time of cold sensation, the position of the control swash plate 36 is controlled to a predetermined position where it comes into contact with the spill pin 35, so that the discharge is substantially performed.
G is narrowed, and the drive shaft 17
The load acting on the device is reduced.

As described above, this fuel pressurizing pump 1
Since the region where the discharge is substantially performed by each plunger 23 is adjusted according to the engine load and the like, unnecessary discharge (pressurization) of the fuel is eliminated, and the power loss of the engine is reduced and fuel efficiency is improved accordingly. At the same time, the drain of the high-pressure fuel after discharge is reduced, and the heat generated by the increase in the drain flow rate is also reduced. Therefore, generation of vapor due to this heat generation is also reliably suppressed.

In particular, in the case of the fuel pressurizing pump 1, since each suction check valve 28 is pushed open by one control swash plate 36 which rotates in synchronization with the drive swash plate 16, the number of parts is extremely small. Although having a simple structure, the opening control of the suction check valves 28 during the discharge operation of the plunger 23 can always be performed at the same timing for all the suction check valves 28.
Manufacturing at low cost is possible, and the number of plungers 23 (the number of cylinder holes 21) can be relatively easily increased or decreased without changing the basic structure of the control swash plate 36 and the like.

Further, in the fuel pressurizing pump 1, since the control swash plate 36 is directly operated by the solenoid valve 44 as an electromagnetic actuator, the response of the control swash plate 36 can be improved. The optimum discharge flow rate required for engine operation can always be obtained immediately.

Further, the fuel pressurizing pump 1 is controlled by the controller 48 so that the pump capacity is reduced during normal engine start and maximized during cold / cold start. At the time of normal engine start, the pump load is reduced to improve the start of the pump, and at the time of cold start, a large amount of fuel is supplied to the injector 6 of the engine to improve the startability of the engine.

In the above embodiment, the solenoid valve 44 of the type that attracts the plunger 45 by excitation of the solenoid 47 is used. On the contrary, the solenoid valve of the type that applies repulsion to the plunger by excitation of the solenoid. It is also possible to employ.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, FIGS.
The configuration of the control swash plate 136 for pressing the spill pin 35 and the forward / backward operation mechanism for operating the control swash plate 136 are different from those of the first embodiment shown in FIG. Therefore, in the following, the same portions as those in the first embodiment are denoted by the same reference numerals, and duplicate description will be omitted.

The control swash plate 136 includes a swash plate main body 137 having an inclined surface for pressing the spill pin 35 and the swash plate main body 1.
The swash plate main body 137 and the support hole 56 formed in the axis of the boss 55 are provided with a boss 55 projecting from the center of the inclined surface of the swash plate 37. Are engaged. The displacement of the control swash plate 136 in the axial direction is restricted by the locking flange 58 formed integrally with the operation rod 57 and the snap ring 59 with respect to the operation rod 57. The end faces of the locking flange 58 and the boss 55, the swash plate body 13
A thrust washer 60 is interposed between each of the back surface of the lock 7 and each of the snap rings 59, and the relative rotation of the control swash plate 136 and the operation rod 57 is allowed. Also, the control swash plate 13
The sixth swash plate main body 137 is slidably fitted in the center hole 138 of the drive swash plate 16. A cutout groove 140 is formed in the outer peripheral surface of the swash plate main body 137 along the axial direction, and a pin 41 supported on the drive swash plate 16 side is slidably engaged with the cutout groove 140. Therefore, the control swash plate 136 is engaged with the drive swash plate 16 slidably in the axial direction and in a state where relative rotation is restricted.

On the other hand, the advance / retreat operating mechanism is constituted by a diaphragm piston 61 which processes the fuel pressure (pressure of the low-pressure regulator 4) in the working chamber 14 (suction passage 27) to obtain the operating force of the operating rod 57. The diaphragm piston 61 has a casing 62 formed of the pump body 12.
The casing 62 is separated by a diaphragm 65 into a pressure chamber 63 into which a control pressure is introduced and an atmosphere chamber 64 into which atmospheric pressure is introduced. The diaphragm 65 is urged in the direction of the pressure chamber 63 by a spring 66 housed in the atmosphere chamber 64, and has a central portion through a retainer 67 through an operation rod 57.
Is connected to the base end. The pressure chamber 63 communicates with a pressure regulating passage 68 formed in the pump body 12 and the cylinder block 15. One end of the pressure regulating passage 68 is closed by a plug 69 fixed to the operation rod 57. I have. Of course, the plug 69 is slidably fitted in the pressure regulating passage 68, but the plug 69
An orifice 70 having a predetermined diameter is formed for introducing the fuel pressure (pressure of the low-pressure regulator 4) into the pressure regulating passage 68.

A drain passage 71 communicating with the fuel tank 3 is connected to the pressure regulating passage 68. An electromagnetic opening / closing valve 72 is interposed in the drain passage 71, and the pressure of the working chamber 14 introduced into the pressure adjusting passage 68 through the orifice 70 is appropriately adjusted by operating the opening / closing valve 72. It has become. The opening / closing operation of the opening / closing valve 72 is controlled by a controller 48. The controller 48 includes an engine load sensor 49, an engine start sensor 50, and a temperature sensor 51 as in the first embodiment.
The same control is performed in response to this signal.

Since the fuel pressurizing pump 101 is configured as described above, the opening / closing valve 72 is completely opened when the engine is fully opened or cold start, and the pressure regulating passage 68 and the pressure chamber 63 are substantially at atmospheric pressure. (Fuel tank pressure).
For this reason, the diaphragm piston 61 is
As a result, the control rod 57 is pushed in by the force, and as a result, the control swash plate 136 retreats to the maximum and separates from the spill pin 35. Therefore, at this time, each plunger 2
Reference numeral 3 indicates that substantial discharge is performed in the entire area of the discharge process, and a sufficient flow rate of fuel is supplied to the injector 6 of the engine.

When the opening / closing valve 72 is opened / closed appropriately according to the engine load or the like, the pressure regulating passage 68 and the pressure chamber 6 are opened.
The pressure of No. 3 is controlled to a pressure corresponding to the operation of the opening / closing valve 72, and as a result, the advance / retreat position of the diaphragm piston 61 is adjusted. Thus, the axially advanced / retracted position of the control swash plate 136 is controlled, and the actual discharge of each plunger 23 during the discharge process is controlled.

In the case of the fuel pressurizing pump 101, substantially the same effects as those of the first embodiment can be obtained in the basic part, but the forward / backward operating mechanism for operating the control swash plate 136 is a solenoid valve. However, since the diaphragm piston 61 is operated by receiving a low fuel pressure, the electric energy required for operating the control swash plate 136 can be extremely small.
Further, the fuel pressure for operating the control swash plate 136 is the plunger 2
Because it is the feed pump pressure before discharge is performed in 3,
There is no loss of pump power (engine power) to operate the control swash plate 136.

Finally, a third embodiment of the present invention will be described with reference to FIG. This embodiment has substantially the same basic configuration as that of the second embodiment, but differs only in the mechanism for moving the control swash plate 136 forward and backward. In the following, the second
Only different parts from the embodiment will be described, and the same parts will be denoted by the same reference numerals and description thereof will be omitted.

The reciprocating operation mechanism of the fuel pressurizing pump 201 processes the fuel pressure in the discharge passage 8 to operate the operating rod 257.
Is constituted by a spool device 80 which obtains the operating force of The spool device 80 includes a small-diameter spool 81 formed at an intermediate position in the axial direction of the operation rod 257, a large-diameter spool 82 formed at a position closer to the base of the operation rod 257 than the small-diameter spool 81, and an operation rod 257. Is provided in the direction of the drive swash plate 16 so that the pressure of the pressure regulating chamber 85 is introduced into the neck portion 84 between the small-diameter spool 81 and the large-diameter spool 82. Here, since the small-diameter spool 81 and the large-diameter spool 82 have different pressure receiving areas, when the pressure in the pressure regulation chamber 85 increases,
The force acting on the operating rod 257 against the spring 83 increases. Therefore, the operating rod 257 is operated to the forward / backward position where the pressure acting on the area difference portion and the force of the spring 83 are balanced.

The pressure control chamber 85 is an electromagnetic 3 port 2
The switching valve 86 is connected to the discharge passage 8 and the suction passage 27 via a position switching valve 86. By appropriately controlling the operation of the switching valve 86, the pressure in the pressure regulating chamber 85 is reduced by the pressure of the suction passage 27 and the pressure of the discharge passage 8. Between the pressures. In this embodiment also, the switching valve 86 is controlled by the controller 48.
Is the engine load sensor 49 as in the first and second embodiments.
The same control is performed by receiving signals from the engine start sensor 50 and the temperature sensor 51.

Since the fuel pressurizing pump 201 is configured as described above, the pressure adjusting chamber 85 is controlled by the controller 48.
The control swash plate 136 is adjusted to a predetermined axial position by the pressure control described above, and the discharge capacity of each plunger 23 is optimally controlled in accordance with the engine load condition, the normal engine start, cold start, and the like. Become like

In the case of the pump of this embodiment, the same basic effects as those of the first and second embodiments can be obtained, but the forward / backward operation mechanism is obtained by processing the high fuel pressure in the discharge passage 8. Therefore, there is a further advantage that the pressure receiving surface on which the control pressure acts can be reduced to reduce the size of the entire pump. Further, since the control swash plate 136 is not directly operated by the power of the electromagnetic actuator, the loss of electric energy is naturally reduced.

In the above, the case where the axial plunger pump according to the present invention is applied to a fuel pressurizing pump of an engine has been described. Of course, this application is not limited to the fuel pressurizing pump, but may be applied to other pumps such as an oil pump. It is also possible to apply to use.

[0052]

As described above, the invention according to claim 1 is
A plurality of spill pins, which forcibly open each suction check valve by a pushing operation, are protruded at a position radially inward of each plunger on an end surface of the cylinder block on the swash plate side so as to advance and retreat freely, In the center of the end face of the swash plate,
A control swash plate facing the end face of the spill pin is slidable in the axial direction, and is mounted in a state locked in the rotation direction, and furthermore, an advance / retreat operating mechanism for moving the control swash plate to an arbitrary axial position. Because of the provision, the region where substantial discharge is performed in each cylinder chamber can be arbitrarily adjusted by the advance / retreat operation mechanism. As a result, unnecessary discharge of hydraulic fluid is eliminated, and power loss is reduced. Heat generation at the drain portion can be prevented.

Further, the invention according to claim 1 has a structure in which each suction check valve is pushed open by one control swash plate which rotates synchronously with the drive swash plate, so that an extremely simple structure with a small number of parts is required. However, the opening control of the suction check valve during the discharge operation of the plunger can be always performed at the same timing for all the suction check valves. Therefore, according to the present invention, manufacturing can be performed at low cost, and the number of plungers (the number of cylinder chambers) can be relatively easily increased or decreased.

According to a second aspect of the present invention, in the first aspect of the invention, the forward / backward operating mechanism is constituted by an electromagnetic actuator, and the control swash plate is directly advanced / retracted by the power of the electromagnetic actuator. In addition, it is possible to always obtain the optimum discharge flow rate by operating the control swash plate forward and backward with good response by the electromagnetic actuator.

According to a third aspect of the present invention, in the first aspect of the present invention, the power of the advance / retreat operating mechanism is obtained by processing the feed pressure of the hydraulic fluid introduced into the suction passage. And the power loss of the pump for operating the forward / backward operation mechanism hardly occurs. As a result, the overall energy loss can be suppressed to an extremely small level.

According to a fourth aspect of the present invention, in the first aspect of the invention, the power of the advance / retreat operating mechanism is obtained by processing the pressure of the hydraulic fluid in the discharge passage, so that electric loss is reduced. In addition, it is possible to reduce the area of the pressure receiving portion of the advance / retreat operation mechanism and to reduce the size of the device.

According to a fifth aspect of the present invention, the pump according to any one of the first to fourth aspects is used as a fuel pressurizing pump for an engine to eliminate unnecessary fuel discharge. And the fuel efficiency is improved, and the heat generated by the excessive drain of the discharged fuel is reduced, so that the generation of vapor due to the generated heat can be prevented.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, an engine load sensor for detecting an engine load state, and a signal received from the engine load sensor, the control swash plate being switched to the engine load state. And a controller for controlling the advance / retreat operation mechanism so as to be displaced to a corresponding position, so that fuel is supplied to the engine at a flow rate corresponding to the engine load at that time, thereby causing a power loss during normal operation. It is possible to obtain the engine output as desired without the need.

According to a seventh aspect of the present invention, in the fifth or sixth aspect of the present invention, an engine start sensor for detecting the start of the engine, and a control swash plate receiving the detection signal of the engine start sensor is connected to the spill pin. The provision of the controller for controlling the advance / retreat operation mechanism so as to be displaced to a predetermined contact position reduces the load on the pump at the time of starting the engine, so that the pump can be started smoothly and the engine starting performance can be improved.

According to an eighth aspect of the present invention, in the first aspect of the invention, there is provided an engine start sensor for detecting the start of the engine, a temperature sensor for detecting the ambient temperature of the engine, A controller that receives the signal of the start sensor and the signal of the temperature sensor, and controls the advance / retreat operation mechanism so that the control swash plate is displaced to a position away from the spill pin when the engine is started under the condition of the set temperature or less. As a result, a sufficient flow rate of fuel can be supplied to the engine during cold / cold start without incurring power loss during normal operation, and the starting performance of the engine is reliably improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view of the embodiment, taken along line AA of FIG. 1;

FIG. 3 is an end view showing the same embodiment as viewed from a line BB in FIG. 1;

FIG. 4 is a displacement comparison diagram of the plunger and the spill pin according to the embodiment.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view taken along the line II of the embodiment.

FIG. 7 is a sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

1, 101, 201: fuel pressurizing pump (axial plunger pump) 9: discharge check valve 15: cylinder block 16: drive swash plate 21: cylinder hole (cylinder chamber) 23: plunger 28: suction check valve 35: spill pin 36, 136: Control swash plate 44: Solenoid valve (advance operation mechanism) 61: Diaphragm piston (advance operation mechanism) 80: Spool device (advance operation mechanism)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 51/04 F02M 51/04 J 59/04 59/04 F04B 49/06 321 F04B 49/06 321 (72 ) Inventor Yoshio Okubo 1370 Onna, Atsugi-shi, Kanagawa Prefecture F-term in Unisia Gex Co., Ltd. CA09 CD26 CE01 CE02 CE13 CE22 DB01 DC00 DC01 DC13 3H045 AA04 AA10 AA15 AA24 AA34 BA32 BA43 CA19 CA21 CA29 DA14 EA33 3H070 AA01 BB04 BB07 BB17 CC11 DD08 DD13 DD32 DD63 DD65 DD68 DD85 DD91

Claims (8)

[Claims] A cylinder block for accommodating a plurality of plungers so as to be able to advance and retreat in the axial direction is provided opposite to a rotationally driven driving swash plate, and each of the plungers is sequentially pressed by the driving swash plate. In an axial plunger pump that repeatedly opens and retracts in the cylinder chamber and opens the corresponding individual suction check valve to open the corresponding individual discharge check valve and discharges the hydraulic fluid sucked into the cylinder chamber, the cylinder block is driven. A plurality of spill pins, which forcibly open each suction check valve by a pushing operation, are protrudingly provided at a radially inner side of each of the plungers on the end surface on the swash plate side so as to advance and retreat, while the drive swash plate is At the center of the end face, a control swash plate facing the end face of the spill pin is attached slidably in the axial direction and locked in the rotating direction,
An axial plunger pump further comprising an advance / retreat operating mechanism for moving the control swash plate to an arbitrary axial position. 2. The axial plunger pump according to claim 1, wherein the reciprocating operation mechanism is constituted by an electromagnetic actuator, and the control swash plate is directly reciprocated by the power of the electromagnetic actuator. 3. The axial plunger pump according to claim 1, wherein the power of the advance / retreat operation mechanism is obtained by processing the feed pressure of the hydraulic fluid introduced into the suction passage. 4. The axial plunger pump according to claim 1, wherein the power of the reciprocating operation mechanism is obtained by processing the pressure of the hydraulic fluid in the discharge passage. 5. The axial plunger pump according to claim 1, wherein the axial plunger pump is used for a fuel pressurizing pump of an engine. 6. An engine load sensor for detecting a load state of an engine, and receiving a signal from the engine load sensor,
The axial plunger pump according to claim 5, further comprising: a controller that controls an advance / retreat operation mechanism so that the control swash plate is displaced to a position corresponding to an engine load state. 7. An engine start sensor for detecting start of an engine, and a detection signal from the engine start sensor,
7. The axial plunger pump according to claim 5, further comprising a controller for controlling an advance / retreat operation mechanism such that the control swash plate is displaced to a predetermined position where the control swash plate abuts on the spill pin. 8. An engine start sensor for detecting the start of the engine, a temperature sensor for detecting the ambient temperature of the engine, and a signal from the engine start sensor and a signal from the temperature sensor. The axial plunger pump according to any one of claims 5 to 7, further comprising: a controller that controls an advance / retreat operation mechanism so that the control swash plate is displaced to a position separated from the spill pin when the engine is started.