JPH08232833A - Variable volume inclined axis type hydraulic rotating machine - Google Patents

Abstract

PURPOSE: To execute feedback control with high accuracy to a tilting angle for a long time by means of a tilting angle sensing means. CONSTITUTION: A feedback link 28 is arranged between a casing 22 of a hydraulic pump and a control part 23 through a support pin 29. A lower end of the feedback link 28 is connected to a valve plate 8 through a connection pin 30, an oscillating link and detection pins 26. A spring plate 31 is arranged on a detection part 28B of the feedback link 28. The spring plate 31 always abuts against a detection rod 35B. Even when minor oscillations generated by rotation of a cylinder block or tilting of the valve plate 8 are transmitted to the feedback link 28, the oscillations are suppressed or attenuated by elasticity of the spring plate 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement type oblique shaft hydraulic rotary machine suitably used as a hydraulic pump or hydraulic motor for civil engineering / construction machinery or other general machinery.

[0002]

2. Description of the Related Art Among hydraulic rotary machines used for a hydraulic pump as a hydraulic power source of hydraulic equipment, a hydraulic motor as a drive source, etc., a variable displacement type oblique shaft type liquid crystal equipped with an oblique axis type variable capacity mechanism. A pressure rotary machine is known.

Therefore, FIG. 7 shows an example of a variable displacement type oblique shaft type hydraulic pump as a conventional variable displacement type oblique shaft type hydraulic rotating machine.

In the drawing, reference numeral 1 denotes a cylindrical casing, and the casing 1 comprises a substantially cylindrical casing body 1A having one end serving as a bearing portion, and a head casing 1B having the other end of the casing body 1A closed. It consists of

Reference numeral 2 denotes a rotary shaft rotatably provided in the casing body 1A, 3 denotes a cylinder block located in the casing body 1A and rotating together with the rotary shaft 2, and the cylinder block 3 has an axial direction thereof. A plurality of cylinders 4 are bored. A piston 5 is slidably provided in each cylinder 4, and a connecting rod 6 is attached to each piston 5.

A spherical portion 6A is formed at the tip of each connecting rod 6, and each spherical portion 6A is connected to the rotary shaft 2
Is swingably supported by a drive disk 7 formed at the tip of the. Here, the cylinder block 3 is arranged with a valve plate 8 described later with a tilt angle θ as a tilt amount with respect to the rotating shaft 2, and the pump displacement is determined by this tilt angle θ.

Reference numeral 8 denotes a valve plate. The valve plate 8 is slidably in contact with the cylinder block 3 on one end face thereof, and the other end face of the valve plate 8 is a tilt-curved tilt slide formed on the head casing 1B. It is slidably in contact with the surface 9. Further, a through hole 8A is bored in the center of the valve plate 8, and tip ends of a later-described center shaft 10 and a swing pin 15 are inserted into the through hole 8A from both sides. The valve plate 8 is provided with a pair of supply / discharge ports (not shown) intermittently communicating with the cylinders 4 when the cylinder block 3 rotates, and is opened in the tilting sliding surface 9 of the head casing 1B. The pair of supply / discharge passages (not shown) communicate with these supply / discharge ports regardless of the tilted position (tilt angle θ) of the valve plate 8.

Reference numeral 10 denotes a center shaft for supporting the cylinder block 3 between the drive disk 7 and the valve plate 8. A spherical portion 10A is formed on one end side of the center shaft 10, and the spherical portion 10A is a drive. It is swingably supported at the axial center position of the disk 7. On the other hand, the other end of the center shaft 10 protruding through the center of the cylinder block 3 is slidably inserted into the through hole 8A of the valve plate 8 to center the cylinder block 3 with respect to the valve plate 8. It is like this.

Reference numeral 11 denotes a tilting mechanism for tilting the valve plate 8 along the tilting sliding surface 9. The tilting mechanism 11 is formed in the head casing 1B and has oil passage holes 12A, 12A on both ends in the axial direction. 12
A cylinder chamber 12 having B, and a fluid pressure chamber 13 that is slidably inserted into the cylinder chamber 12 and is in the cylinder chamber 12.
A servo piston 14 defining A and 13B, and a base end side fixed to the servo piston 14 and a tip side serving as a spherical tip portion 15A swingably inserted into the through hole 8A of the valve plate 8 And a moving pin 15.

Reference numeral 16 is a control unit for controlling the tilting of the valve plate 8 via the tilting mechanism 11, and the control unit 16 is the head casing 1.
A throttle switching valve (none of which is shown) provided outside B is provided for feedback controlling the amount of pressure oil (pilot pressure) supplied and discharged from the pilot pump. A sleeve (not shown) is provided in the throttle switching valve, and the sleeve and the servo piston 14 are connected to the feedback pin 17 inserted into the elongated hole 1C of the head casing 1B.
Are integrally connected by.

When the throttle switching valve of the control unit 16 is switched by an operation lever or the like, pressure oil (pilot pressure) corresponding to the switching operation amount at this time is supplied from the pilot pump to the oil passage holes 12A, 12B. Is supplied to and discharged from the hydraulic chambers 13A, 13B of the tilting mechanism 11 via the
By slidingly displacing the servo piston 14 by the pressure difference between B, the servo piston 14 tilts the valve plate 8 and the cylinder block 3 through the swing pin 15 at the tilt angle θ in the arrow A direction. . The sleeve of the throttle switching valve is displaced following the displacement of the servo piston 14 to feedback control the amount of pressure oil from the pilot pump, and the displacement amount of the servo piston 14 is controlled by the switching operation amount of the throttle switching valve. It keeps the state corresponding to.

The variable displacement type oblique shaft type hydraulic pump according to the prior art has the above-mentioned structure, and its operation will be described below.

First, when the cylinder block 3 is tilted together with the valve plate 8 by the tilting mechanism 11 in the direction of arrow A at a tilt angle θ, pressure oil from the pilot pump controlled by the controller 16 (pilot Pressure) is supplied to and discharged from the hydraulic chamber 13A (13B) through the oil passage holes 12A, 12B of the tilting mechanism 11 and the like, whereby the servo piston 14 is moved to the cylinder chamber 1
Sliding displacement within 2. Then, the servo piston 14
Is integrally displaced with the rocking pin 15, so that the valve plate 8
Is tilted while sliding on the tilt slide surface 9, and the cylinder block 3 is tilted together. As a result, the rotation center of the cylinder block 3 has a tilt angle θ with respect to the rotation center of the rotation shaft 2, and is, for example, the minimum. The tilting position is tilted to the maximum tilting position, and the state shown in the drawing is obtained.

Next, when the rotary shaft 2 is rotationally driven by a drive source such as an engine, a connecting rod 6 is provided between the drive disk 7 of the rotary shaft 2 and each piston 5 inserted in each cylinder 4 of the cylinder block 3. Since they are connected, the cylinder block 3 is rotated together with the rotating shaft 2, and the rotation of the cylinder block 3 causes the pistons 5 to reciprocate in the cylinder 4. Then, when each piston 5 retracts (extends) from the inside of the cylinder 4, it becomes an intake stroke in which hydraulic oil is sucked into the cylinder 4 from the supply / discharge passage through the supply / discharge port, and the piston 5 enters (reduces) into the cylinder 4. ), Pressurizing the hydraulic oil in the cylinder 4,
The discharge process is to discharge from the supply / discharge passage via the supply / discharge port.

Thus, the rotary shaft 2 is rotationally driven from the outside to reciprocally move each piston 5 in each cylinder 4, so that the hydraulic oil sucked into each cylinder 4 in the suction stroke of each piston 5 is discharged. Pressurize and discharge high pressure oil into the hydraulic piping.

[0016]

In the prior art described above, when the valve plate 8 slides on the tilt sliding surface 9, the valve plate 8 makes an arc motion, whereas the servo piston 14 moves. Moves vertically in the cylinder chamber 12, so that when the tilting mechanism 11 tilts the valve plate 8, the spherical tip portion 15A of the swing pin 15 fixed to the servo piston 14 causes the valve plate 8 to move. It swings or slides within the through hole 8A. In order to smoothly swing or slide the tip portion 15A of the swing pin 15 in the through hole 8A, at least a slight gap should be provided between the tip portion 15A of the swing pin 15 and the through hole 8A. This gap must be provided, and this gap gradually expands due to wear while the hydraulic pump is operated for a long time and the tilt of the valve plate 8 and the like is repeated.

Therefore, in the prior art, the play is caused by the gap between the through hole 8A of the valve plate 8 and the tip portion 15A of the rocking pin 15, and the play causes the valve plate 8 to move.
There is an error between the actual tilted position of the valve plate 8 and the position of the valve plate 8 detected by the feedback pin 17 via the swing pin 15,
There is a drawback in that the tracking accuracy of the control unit 16 via the feedback pin 17 is deteriorated, and the performance of the control unit 16 during feedback control is significantly reduced.

Further, the feedback pin 17 for transmitting the tilt angle θ of the valve plate 8 to the control portion 16 is directly fixed to the servo piston 14 for tilting the valve plate 8, and the servo piston 14
Since the control unit 16 is provided on the outer side surface of the head casing 1B so that the amount of displacement of the head and the amount of displacement of the feedback pin 17 are the same, the control unit 16 largely projects rearward from the casing 1 and the entire size increases. However, there is a drawback that it cannot be made compact.

On the other hand, in order to solve the above-mentioned drawbacks, the present applicant has previously filed Japanese Patent Application No. 59-103891 (Act No.
No. 41257), a tilting amount (tilt angle θ) of the valve plate is provided by providing a control unit on the upper side of the casing and connecting the control unit and the valve plate with a link or the like extending into the casing. It is possible to directly feed back the tilt angle θ from the valve plate instead of indirectly feeding back the tilt angle through the tilting mechanism to improve the responsiveness of the control unit and the tracking accuracy with respect to the valve plate, and A variable displacement type oblique shaft type hydraulic rotating machine (hereinafter referred to as other conventional technology) has been proposed for the purpose of downsizing.

However, when these hydraulic rotary machines are used as variable displacement hydraulic pumps, the recent trend is to require more precise control of the pump displacement, and for this purpose the valve plate is required. Therefore, it is necessary to separately provide a tilt amount detecting means so that the tilt angle θ or the tilt amount can be constantly monitored. However, if the tilt amount detecting means is added to these hydraulic rotary machines, there is a problem that not only the entire structure becomes more complicated, but also the apparatus becomes large and it is difficult to form it compactly.

Therefore, in order to solve the above-mentioned problems, the inventors of the present invention have previously applied Japanese Patent Application No. 5-346168 to a link mechanism whose base end side is connected to a valve plate and a tip end side of the link mechanism. A valve having a contacting rod and tilting amount detecting means for detecting the displacement amount when the tip end side of the link mechanism is displaced due to tilting of the valve plate. We have proposed a variable displacement oblique shaft type hydraulic rotating machine that can directly take out the tilt angle θ of the plate.

However, in the variable displacement type oblique shaft type hydraulic rotary machine proposed in Japanese Patent Application No. 5-346168, when this hydraulic rotary machine is used as a hydraulic pump, the pressure applied in the cylinder is increased. When oil is discharged from the discharge port to the supply / discharge pipes, a small discharge vibration occurs, or when the valve plate tilts and fluctuates with respect to the tilting sliding surface, the oil may flow between the valve plate and the tilting sliding surface. Small vibrations that occur are transmitted from the rocking link of the link mechanism to the feedback link, which also vibrates the detection rod, and this vibration causes the rotation of the link mechanism tip side that follows the tilting of the valve plate. The amount of dynamic displacement is
There is an unsolved problem that it is difficult to accurately transmit to the detection rod, and it is not possible to sufficiently obtain highly accurate feedback control corresponding to the actual tilt angle θ of the valve plate.

Further, due to the vibration, the contact portion between the tip end side of the feedback link and the detection rod is apt to wear, and due to this wear, the detection position detected by the tilt amount detecting means and the tilt of the valve plate. An error may occur between the actual displacement amount of the link mechanism tip side corresponding to the angle θ, and this also makes it possible to perform highly accurate feedback control corresponding to the tilt angle θ of the valve plate for a long period of time. There is an unsolved problem that it can not be done.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when the tilt amount detecting means is provided, it is possible to prevent the entire structure from becoming complicated and to reduce the size. Another object of the present invention is to provide a variable displacement type oblique shaft type hydraulic rotary machine in which highly accurate feedback control with respect to the tilt angle can be performed for a long period by the tilt amount detecting means.

[0025]

In order to solve the above-mentioned problems, a variable capacity type oblique shaft type hydraulic rotating machine according to the present invention has a cylindrical casing whose end surface is closed by a head casing, and a casing inside the casing. A rotatable rotation shaft, a cylinder block provided in the casing so as to rotate together with the rotation shaft, and having a plurality of cylinders formed in the axial direction, and slidable in each cylinder of the cylinder block. And a plurality of pistons swingably supported by the rotary shaft via a connecting rod, one end face of the piston slidably contacts the cylinder block, and the other end face of the head casing tilts and slides. The valve plate is slidably in sliding contact with the valve plate, and the tilting mechanism tilts the cylinder block together with the valve plate.

The features of the configuration adopted by the present invention are as follows.
In order to supply and discharge the pressure oil for tilt control to the tilt mechanism, a control unit provided on the casing located on the minimum tilt side of the valve plate and supported between the control unit and the casing. A feedback link that is rotatably provided via a pin, and has a distal end that serves as a detection unit that projects toward the control unit, and a proximal end that serves as a connecting part that projects into the casing, and a distal end that connects the feedback link. Is rotatably connected to
In order to feed back to the control unit in a state where the tilting amount of the base plate is rotatably attached to the valve plate and the tilt amount of the valve plate is proportionally reduced, the feedback link is in the middle of the detection unit. An output pin provided on the control unit, and a detection rod that is provided outside the control unit and that follows the rotational displacement of the feedback link. By detecting the displacement amount of the detection rod, the tilt amount of the valve plate is detected. A vibration amount detecting means for extracting the vibration, which is in contact with a detection rod of the tilt amount detecting means, and which suppresses transmission of a small vibration from the feedback link to the detection rod of the detection part of the feedback link. There is a suppressor.

[0027]

As described above, the feedback link is provided between the casing and the control section through the support pin, and the base end side of the swing link whose tip side is connected to the connection section of the feedback link is the valve plate. Since the valve plate is attached via the detection pin, the tilt amount of the valve plate can be directly taken out as the rotational displacement amount of the feedback link via the swing link. Since the output portion is provided in the detection portion of the feedback link, the dimension R from the mounting portion of the swing link to the valve plate to the tilt center of the cylinder block and the support pin As the ratio of the dimension r to the output pin, the tilt amount of the valve plate can be output to the control unit in a state where the tilt amount is proportionally reduced.

Further, since the tilting amount detecting means is constructed so as to take out the rotational displacement amount of the feedback link from the tip of the detecting portion, the tip of the detecting portion with respect to the dimension r from the supporting pin to the output pin can be obtained. As a ratio of the dimension L of the feedback link, the rotational displacement of the feedback link can be proportionally increased and taken out, and the tilt amount of the valve plate can be detected more accurately.

In addition, since the vibration suppressor for suppressing the small vibration transmitted to the feedback link is provided in the detection portion of the feedback link so as to contact the detection rod of the tilt amount detecting means, the vibration is suppressed. It can be suppressed by the body, this vibration can be reliably prevented from being transmitted from the detection part of the feedback link to the detection rod, and at the same time, the contact part between the detection rod and the vibration suppression body can be prevented from being locally worn. The detection error due to the vibration can be eliminated.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technique shown in FIG. 7 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 21 is a variable displacement oblique shaft type hydraulic pump according to the present embodiment, 22 is a casing of the hydraulic pump 21, and the casing 22 has a cylindrical shape similar to the casing 1 described in the prior art. Although it is composed of a casing main body 22A and a head casing 22B, an opening 22C is formed in the casing 22. Here, the opening 22C corresponds to the cylinder block 3 or the valve plate 8
The casing body 22A so that it is located on the minimum tilt side of
It is open to the upper side of the peripheral body of the.

Reference numeral 23 is a control unit of the tilting mechanism 11, and the control unit 23 is provided with a casing 24 provided on the upper side of the peripheral body of the casing main body 22A so as to cover the opening 22C of the casing 22, and the casing 24. A throttle switching valve 3 which will be described later and is provided in 24.
And 8.

Reference numeral 25 is a link mechanism as a feedback mechanism for feeding back the tilt amount (tilt angle θ) of the valve plate 8 to the control section 23. The link mechanism 25 is shown in FIGS.
As shown in, the pair of detection pins 26, 26 rotatably attached to the left and right side surfaces of the valve plate 8 at the position of the dimension R from the tilt center O of the cylinder block 3 and the lower end side straddle the cylinder block 3. As described above, it is roughly composed of a swinging link 27, which is branched into two in a circular arc shape, and each end of which is attached to the valve plate 8 through each of the detection pins 26, and a feedback link 28 described later. There is.

Reference numeral 28 denotes a feedback link forming a part of the link mechanism 25, and the feedback link 2
As shown in FIG. 2, the reference numeral 8 is rotatably mounted in the opening 22C of the casing 22 between the housing 24 of the control unit 23 and the casing main body 22A via a support pin 29.
Then, the lower end side of the feedback link 28 projects into the casing 22 from the opening 22C to form a bifurcated connecting portion 28A, and the connecting portion 28A is rotatable to the upper end of the swing link 27 via the connecting pin 30. Are linked to.

Further, the upper end side of the feedback link 28 serves as a detector 28B, which is shown in FIG.
As shown in FIG. 3, a spring plate 31, which will be described later, is provided so as to project upward in the housing 24 of the control unit 23. Here, in order to improve the responsiveness of the feedback link 28 to the tilting movement of the valve plate 8, the connecting portion 28A and the detecting portion 28B are integrally formed, for example, from an aluminum material by die casting or the like, and the entire weight is reduced. Further, screw holes 28C, 28C for tightening the spring plate 31 with bolts 32 described later are provided on the upper end side of the feedback link 28.
C is provided.

Reference numeral 31 denotes a spring plate which is fixedly provided on the upper end side of the feedback link 28 and constitutes a part of the detecting portion 28B as a vibration suppressor. The spring plate 31 is an elongated metal plate having a spring property. 2 in a "ku" shape
The mounting portion 31A formed by bending in a step and located on the base end side, the bending portion 31B obliquely bent from the mounting portion 31A, and the mounting portion 31A located on the tip side of the bending portion 31B. The contact portion 31C extends in parallel.

Here, the mounting portion 3 of the spring plate 31
1A connects the bolts 32, 32 to the feedback link 2
By screwing into each screw hole 28C on the tip side of 8,
It is fastened to the tip end side of the feedback link 28.
Then, the spring plate 31 extends into the sensor case 34 described later, and the contact portion 31C of the spring plate 31 contacts the tip portion 35F of the detection rod 35B described later with a spring property, so that a small amount from the feedback link 28. The vibration is suppressed from being directly transmitted to the detection rod 35B.

Reference numeral 33 denotes an output pin fixed to an intermediate portion of the detecting portion 28B of the feedback link 28, which is the output pin 3
3 is connected to a sleeve 38A of a throttle switching valve 38 described later. Here, the output pin 33 corresponds to the support pin 29.
Is provided in the middle of the detecting portion 28B of the feedback link 28 at a position of a size r from the center of the cylinder, and this size r is reduced in proportion to the size R from the tilt center O of the cylinder block 3 to the detection pin 26. There is. Further, the contact portion 31C of the spring plate 31 is connected to the tip portion 35F of the detection rod 35B.
The dimension L from the portion that abuts to the support pin 29 is twice as large as the dimension r before and after the dimension r, and the rotational displacement amount of the feedback link 28 from the tilt amount sensor 35 described later is proportionally set. It is made large so that it can be taken out.

Reference numeral 34 denotes a sensor case provided on the housing 24 of the control unit 23. The sensor case 34 has a detection chamber 34A from which the contact portion 31C of the spring plate 31 and the like project.
A sensor mounting hole 34B which is opened in the detection chamber 34A and in which the tilt amount sensor 35 is mounted is formed, and the detection chamber 34A is closed by a plug 34C.

Reference numeral 35 denotes a tilt amount sensor as a tilt amount detecting means provided in the sensor case 34. The tilt amount sensor 35 is a sensor body screwed into a sensor mounting hole 34B of the sensor case 34. 35A, a detection rod 35B having a base end side slidably inserted into the sensor body 35A, and a tip end side protruding into the detection chamber 34A of the sensor case 34,
A detection body 35C such as a magnet provided on the base end side of the detection rod 35B and a detection unit 35D provided in the sensor body 35A and detecting the displacement amount of the detection body 35C.
Etc.

Here, the detection rod 35B is formed of a non-magnetic material such as stainless steel, and has a large-diameter disk-shaped spring that slides in the sensor mounting hole 34B of the sensor case 34 at its axially intermediate portion. The receiving portion 35E is integrally provided.

36 is a spring receiving portion 35E of the detecting rod 35B.
Is a compression spring that is compressed between the sensor body 35A and the sensor body 35A.
Is constantly urged to the detection chamber 34A side of the detection rod 3
The tip portion 35F of 5B is located in the detection chamber 34 of the sensor case 34.
In A, it constantly contacts the contact portion 31C of the spring plate 31 with a pressure corresponding to the biasing force of the compression spring 36.

Therefore, the tilt amount sensor 35 detects the detecting portion 28 of the feedback link 28 in accordance with the tilt movement of the valve plate 8.
When B (spring plate 31) is rotationally displaced, the detection unit 35D detects the amount of displacement of the detection target 35C that is axially displaced together with the detection rod 35B, so that the rotational displacement of the feedback link 28 is determined by the valve plate. The tilt angle θ of 8 is detected.

Here, small vibrations or the like generated between the valve plate 8 and the tilt sliding surface 9 due to the rotation of the cylinder block 3 and the tilting motion of the valve plate 8 are transmitted to the detecting portion 28B of the feedback ring 28. However, since this vibration is suppressed by the pulling plate 31, it is possible to prevent the vibration from being transmitted from the detection unit 28B to the detection rod 35B, and an actual detection unit corresponding to the tilt angle θ of the valve plate 8. The displacement amount of 28B can be transmitted to the tilt amount sensor 35 side. Further, since the vibration is suppressed by the spring plate 31, it is possible to prevent the contact portion between the spring plate 31 and the tip portion 35F of the detection rod 35B from being locally worn for a long period of time. Also, the actual displacement amount of the detection unit 28B corresponding to the tilt angle θ of the valve plate 8 can be transmitted to the tilt amount sensor 35 side.

Reference numeral 37 denotes a tilt amount sensor 3 in the sensor case 34.
5 shows a lock nut fastened to the lock nut 37.
Is screwed onto the outer peripheral side of the tilt amount sensor 35, for example, the tilt amount sensor 35 is appropriately advanced and retracted from the sensor case 34, and after the position adjustment (zero point adjustment) of the detection target 35C with respect to the detection portion 35D is performed. The tilt amount sensor 35 is positioned on the sensor case 34.

Next, 38 is a throttle switching valve provided in the housing 24 of the control unit 23. The throttle switching valve 38 is the pilot pump 39, the tank 40 and the cylinder chamber 1 of the tilting mechanism 11.
The pressure oil (pilot pressure) from the pilot pump 39, which is provided between the two and is provided in the middle of the pipelines 41A and 41B.
38A for feedback control of the throttle valve, a valve spring 38B for constantly urging a spool (not shown) of the throttle switching valve 38 toward a neutral position, and a spool of the throttle switching valve 38 against the valve spring 38B. And a hydraulic pilot portion 38C for switching operation.

Here, the sleeve 38 of the throttle switching valve 38
A is connected to the feedback link 28 of the link mechanism 25 via the output pin 33, and the tilt of the valve plate 8 is transmitted via the link mechanism 25, whereby the displacement amount corresponding to the tilt angle θ at this time. Slidingly displaces. When the pilot pressure from the pilot pump 39 is supplied to the hydraulic pilot portion 38C via the pressure reducing valve 43, which will be described later, the throttle switching valve 38 switches from the neutral position to the left or right switching position according to the pilot pressure. Then, the pressure oil from the pilot pump 39 is supplied to and discharged from the hydraulic chambers 13A and 13B of the servo piston 14 via the pipe lines 41A and 41B, and the valve plate 8 is tilted by the servo piston 14 together with the cylinder block 3.

At this time, the sleeve 3 of the throttle switching valve 38
8A is displaced following the tilting of the valve plate 8 so that the tilting angle θ of the valve plate 8 becomes a tilting amount corresponding to the pilot pressure supplied to the hydraulic pilot portion 38C. The amount of pressure oil supplied to and discharged from the hydraulic pressure chambers 13A and 13B is feedback-controlled to keep the tilt angle θ of the valve plate 8 constant until the pilot pressure changes.

Reference numeral 42 denotes a pilot line connecting between the hydraulic pilot portion 38C of the throttle switching valve 38 and the pilot pump 39, and 43 denotes an electromagnetic proportional pressure reducing valve provided in the middle of the pilot line 42, The pressure reducing valve 43 is provided with an electromagnetic proportional solenoid portion 43A, and its set pressure is variably controlled according to a current value of a control signal Ip output from a controller 46 described later. The pressure reducing valve 43 changes the pilot pressure supplied from the pilot pump 39 to the hydraulic pilot portion 38C of the throttle switching valve 38 based on the set pressure, and the throttle switching valve 3 is changed according to the pilot pressure.
8 is switched from the neutral position to the left or right switching position.

Reference numeral 44 indicates a command device, which outputs a tilt angle command θso for commanding a target tilt angle θp of the hydraulic pump 21 in accordance with a command operation by an operator or the discharge pressure of the hydraulic pump 21. .

Reference numeral 45 denotes a selection switch. The selection switch 45 is turned on and off by an operator, and in order to limit the discharge amount of the pressure oil discharged from the hydraulic pump 21, a target limit tilt angle θpb (limit tilt tilt The angle θsb) is output. Here, the target limit tilt angle θpb is equal to the hydraulic pump 21.
When tilting the valve plate 8 and so on, for example, as shown in FIG. 5, with respect to the maximum tilt angle θmax at which the valve plate 8 can be tilted,

[0052]

## EQU1 ## It is set as θpb = 0.8 × θmax. Then, the selection switch 45 becomes O
When operated N, the controller 46 causes the valve plate 8
The tilt angle θ is restricted to the target limit tilt angle θpb or less.

Reference numeral 46 denotes a controller constituted by a microcomputer or the like, the input side of which is connected to the tilt amount sensor 35, the command device 44, the selection switch 45, etc., and the output side is the solenoid portion 43A of the pressure reducing valve 43. Etc. are connected to. The controller 46 stores the program shown in FIG. 6 in its storage circuit and performs tilting angle control processing based on the actual tilting angle θ of the hydraulic pump 21. Further, in the storage circuit of the controller 46, in the storage area 46A, the tilt angle control map illustrated in FIG.
Also, a hysteresis value k or the like for setting the dead zone area is stored.

The present embodiment is constructed as described above, and the basic operation of the variable displacement oblique shaft hydraulic pump 21 is not significantly different from that of the prior art described above.

Therefore, the tilting angle control processing of the hydraulic pump 21 by the controller 46, which is a feature of this embodiment, will be described with reference to FIGS.

First, when the processing operation is started, the tilt angle command θso from the command device 44 is read in step 1, and the process proceeds to step 2 to read the current tilt angle θ from the tilt amount sensor 35.
Read (actual tilt angle θ). Then, in step 3, it is determined whether or not the selection switch 45 is turned on,
When it is determined to be "NO", the selection switch 45 is turned off.
Since it is in the state, the process proceeds to step 4, and the tilt angle command θso is entered in the tilt angle command θs after the selection switch.

When it is judged "YES" in step 3, the selection switch 45 is turned on. Therefore, the process proceeds to step 5 and the tilt angle command θso at this time corresponds to the target limit tilt angle θpb. Limited tilt angle θsb (θsb = θ
pb) It is judged whether or not it is more than. When it is determined to be "YES" in step 5, the process proceeds to step 6 and the tilt angle command θs after the selection switch is limited to the tilt angle θ.
sb enters. As a result, the upper limit can be set for the tilt angle command θs. For example, it is limited to 80% of the maximum tilt angle θmax, and the maximum discharge amount of the hydraulic pump 21 is limited to limit the maximum rotation speed of the traveling hydraulic motor (not shown) or the working hydraulic cylinder (see FIG. By controlling the operating speed of (not shown), operability and safety can be improved.

On the other hand, when it is determined to be "NO" in step 5, since the tilt angle command θso at this time is smaller than the limited tilt angle θsb, the process proceeds to step 4 and the tilt angle command θs after the selection switch is set. The tilt angle command θso is entered.

Next, as described above, when the tilt angle command θs after the selection switch is determined in step 4 or step 6, the process proceeds to step 7 and the tilt angle command θs after the selection switch.
The tilt angle difference Δθ between s and the actual tilt angle θ is

[0060]

[Mathematical formula-see original document] Calculation is performed with Δθ = θs−θ. Then, in step 8, it is determined whether or not the tilt angle difference Δθ is equal to or less than the hysteresis value k.

Here, the hysteresis value k sets a dead zone for determining whether or not the tilt angle command θs and the actual tilt angle θ substantially coincide with each other. If it is set to zero (k = 0), a problem such as hunting may occur, and a small value that does not affect the accuracy is usually entered.

When it is determined to be "YES" in step 8, the tilt angle command θs and the actual tilt angle θ are substantially coincident with each other. θs

[0063]

## EQU00003 ## The target tilt angle .theta.p is set as .theta.p.rarw..theta.s.

If it is determined to be "NO" in step 8, the process proceeds to step 10 and the tilt angle difference Δθ is zero (Δθ
> 0), the sign of the tilt angle difference Δθ is determined. When it is determined to be “YES” in step 10, it means that the tilt angle difference Δθ is a positive value and the tilt angle command θs is larger than the actual tilt angle θ.
To the tilt angle command θs in the direction to increase the actual tilt angle θ.
The target tilt angle θp is

[0065]

## EQU4 ## Calculated as θp = θs + Δθ.

On the other hand, when it is judged "NO" in step 10, the tilt angle difference Δθ is a negative value and the tilt angle command θ
Since s is smaller than the actual tilt angle θ, the target tilt angle θp is changed to step 12 so as to correct the tilt angle command θs in the direction of decreasing the actual tilt angle θ.

[0067]

[Equation 5] Calculated as θp = θs−Δθ.

Next, as described above, step 9 and step 1
When the target tilt angle θp is determined in 1 or step 12, the control signal Ip based on the target tilt angle θp is obtained from the tilt angle control map shown in FIG. 5 in step 13 and this control signal Ip is calculated. The current value is output to the solenoid portion 43A of the pressure reducing valve 43, and the process returns in step 14.

Thus, by repeating the above-described control processing, the tilt angle difference Δθ becomes smaller, and the tilt angle command θ
s and the actual tilt angle θ can be substantially matched.
That is, the set pressure of the pressure reducing valve 43 is variably controlled according to the control signal Ip, so that the pilot pump 39 changes the throttle switching valve 3
The pilot pressure corresponding to this set pressure is supplied to the hydraulic pilot section 38C of No. 8. As a result, the throttle switching valve 38
Is switched from the neutral position to the left or right switching position according to the pilot pressure at this time, and the pressure oil from the pilot pump 39 is supplied to the hydraulic chambers 13A, 13B of the servo piston 14 via the pipe lines 41A, 41B. Then, the valve plate 8 is tilted by the servo piston 14 together with the cylinder block 3.

The tilt angle θ of the hydraulic pump 21 becomes the tilt amount corresponding to the tilt angle command θs, and the throttle switching valve 3
The sleeve 38A of No. 8 is displaced following the tilting of the valve plate 8,
The amount of pressure oil supplied from and discharged from the pilot pump 39 to the hydraulic chambers 13A and 13B is fed back so that the tilt angle θ of the valve plate 8 becomes a tilt amount corresponding to the pilot pressure supplied to the hydraulic pilot portion 38C. Control. As a result, the tilt angle θ of the valve plate 8 is held at an angle corresponding to the tilt angle command θs until the pilot pressure changes, and the hydraulic pump 21 changes the flow rate corresponding to the tilt angle θ at this time. Pressure oil is discharged.

Thus, according to this embodiment, the hydraulic pump 2
The tilt amount sensor 35 is provided on the casing 22 of the first unit via the housing 24 of the control unit 23 and the sensor case 34, and the tilt displacement sensor 35 determines the amount of rotational displacement of the feedback link 28 by tilting the valve plate 8. Since the angle θ is taken out, the tilt angle θ of the valve plate 8 can be constantly monitored by the tilt amount sensor 35, and the pump displacement of the hydraulic pump 21 can be controlled with higher accuracy. The additional functions such as the flow rate restriction function can be supported only by changing the software.

That is, as described in the tilt angle control process, the tilt angle command θs (tilt angle command θso) read from the command device 44 and the actual tilt angle read from the tilt amount sensor 35. Angle θ
From this, the tilt angle difference Δθ is calculated as in the equation (2) above, and the tilt angle command θs is corrected by this tilt angle difference Δθ to calculate the target tilt angle θp. The target tilt angle θp can be feedback-controlled based on the turning angle θ, and the pump displacement can be controlled with high accuracy.

When the operator turns on the selection switch 45, the controller 46 causes the valve plate 8 to move.
It is possible to limit the actual tilt angle θ such as the following to a target limit tilt angle θpb (limit tilt angle θsb) or less, and by limiting the maximum discharge amount of the hydraulic pump 21, It is possible to reliably improve operability and safety by limiting the number of revolutions or limiting the operating speed of the working hydraulic cylinder.

A feedback link 28 is provided between the casing 22 of the hydraulic pump 21 and the housing 24 of the control section 23 via a support pin 29, and the upper end side is connected to a connecting section 28A of the feedback link 28. Since the lower end side of the swing link 27 is attached to the valve plate 8 via the detection pins 26, the tilt angle θ of the valve plate 8 is used as the rotational displacement amount of the feedback link 28 via the swing link 27. It can be taken out directly. Since the detection portion 28B of the feedback link 28 is provided with the output pin 33 located in the middle of the detection portion 28B, the tilting center of the cylinder block 3 from the mounting portion (detection pin 26) of the swing link 27 to the valve plate 8 is provided. As the ratio of the dimension R up to O and the dimension r from the support pin 29 to the output pin 33, the tilting amount that is the tilt angle θ of the valve plate 8 is proportionally reduced, and the control unit 2
3 to the sleeve 38A.

As a result, each detection pin 2 provided on the valve plate 8
6. The tilt angle θ of the valve plate 8 can be directly detected by the swing link 27, the feedback link 28, etc., and the follow-up control of the control unit 23 with respect to the tilt of the valve plate 8 does not occur. The responsiveness, tracking accuracy, control performance, and the like of the control unit 23 can be greatly improved. The tilt amount of the valve plate 8 is determined by the tilt center O of the cylinder block 3.
By appropriately setting the ratio between the dimension R from the detection pin 26 to the detection pin 26 and the dimension r from the support pin 29 to the output pin 33, the tilt amount can be reduced and transmitted to the control unit 23. The degree of freedom in designing the throttle switching valve 38 and the sleeve 38A of the portion 23 is increased, and the link mechanism 25 including the detection pins 26, the swing link 27, the feedback link 28, and the like and the control portion 23 can be downsized.

Further, in the tilt amount sensor 35, the tip end 35F of the detection rod 35B is constantly fed back to the feedback link 28.
Since the rotation displacement amount of the feedback link 28 is taken out as the displacement amount of the detection rod 35B by contacting the tip end side (contact portion 31C) of the spring plate 31, the support pin 29 to the output pin 33 As a ratio of the dimension L up to the tip of the detection portion 28B (the contact portion 31C of the spring plate 31) with respect to the dimension r, the rotational displacement amount of the feedback link 28 can be proportionally increased and taken out. The sensor 35 can detect the tilt angle θ of the valve plate 8 more accurately, and the tilt amount sensor 3
5 can be compactly attached to the control unit 23 of the hydraulic pump 21.

Moreover, a spring plate 31 serving as a detecting portion 28B is fixed to the tip end side of the feedback link 28 via each bolt 32, and the abutting portion 31C of the spring plate 31 is attached to the tip end portion of the detecting rod 35B. Since it is configured to abut on 35F with a spring property, a small vibration that occurs between the valve plate 8 and the tilt sliding surface 9 due to the tilting motion of the valve plate 8 or a pressure oil discharge stroke is caused. Even if a small discharge vibration or the like generated when the pressure oil in the cylinder 4 is discharged from the supply / discharge port to the supply / discharge passage is transmitted to the detection portion 28B of the feedback link 28 from the swing link 27, Since the vibration suppresses the vibration, it is possible to prevent the vibration from being transmitted from the detection portion 28B of the feedback ring 28 to the detection rod 35B of the tilt amount sensor 35.

Therefore, the rotational displacement amount of the detecting portion 28B of the feedback link 28 detected by the tilt amount sensor 35,
The actual displacement amount of the detection unit 28B corresponding to the tilt amount of the valve plate 8 can be accurately matched, and the tilt angle θ of the valve plate 8 and the like can be accurately matched.
It is possible to perform a highly accurate feedback control with respect to the above for a long time.

Further, the contact portion 31C of the spring plate 31
Since it is possible to prevent the contact portion between the end portion 35F of the detection rod 35B and the tip portion 35F from being locally worn due to the vibration, the detection portion 28B of the feedback link 28 detected by the tilt amount sensor 35 also by this. The rotational displacement of the valve plate 8 and the actual displacement of the detection unit 28B corresponding to the tilt amount of the valve plate 8 can be accurately corresponded to each other, and highly accurate feedback control with respect to the tilt angle θ of the valve plate 8 and the like can be performed. Can be performed over a long period of time.

Furthermore, since the housing 24 of the control unit 23 can be provided on the minimum tilt side of the valve plate 8 and provided outside the peripheral body portion of the casing body 22A, the hydraulic pump 21 concerned.
The degree of freedom in design can be increased when manufacturing the hydraulic pump, the axial length can be reliably shortened as compared with the prior art illustrated in FIG. It is possible to reduce the size of the whole, including.

Therefore, according to this embodiment, by providing the tilt amount sensor 35, the tilt angle θ of the valve plate 8 can be constantly monitored (monitored), and the pump displacement of the hydraulic pump 21 can be controlled with higher accuracy. In addition, the tilt amount sensor 35
As a result, it is possible to prevent the entire structure of the hydraulic pump 21 from becoming complicated, and it is possible to achieve various effects such that the entire structure can be made compact and downsized.

In the above embodiment, the vibration suppressing body provided as the detecting portion 28B on the upper end side of the feedback link 28 is described as being formed by the spring plate 31, but the present invention is not limited to this, and for example, a damping steel plate. A vibration suppressor having excellent vibration damping property is provided on the upper end side of the feedback link.
It may be configured to be brought into contact with the tip portion 35F of 5B.

Further, in the above embodiment, the selection switch 45
When the operator turns ON, the maximum tilt angle θ at which the valve plate 8 can be tilted is limited to the target limit tilt angle θpb or less, which is 80% of the actual maximum tilt angle θmax. However, the present invention is not limited to this, and for example, within the range of 60 to 90% of the maximum tilt angle θmax, the target limit tilt angle θ is set.
You may make it set pb suitably.

[0084]

As described above in detail, according to the present invention, the tilting control unit is provided on the casing located on the minimum tilting side of the valve plate, and is supported between the control unit and the casing. Since the feedback link is provided through the pin and the base end side of the swinging link whose tip end side is connected to the connecting portion of the feedback link is attached to the valve plate through the detection pin, the tilt of the valve plate is detected. The rotation amount can be directly taken out as the rotation displacement amount of the feedback link via the swing link. Since the output portion is provided in the detection portion of the feedback link, the dimension R from the mounting portion of the swing link to the valve plate to the tilt center of the cylinder block and the support pin As the ratio of the dimension r up to the output pin, the tilt amount of the valve plate can be output to the control unit in a proportionally reduced state,
The control unit can be made compact and the degree of freedom in designing the control unit can be increased.

Further, since the tilt amount detecting means takes out the rotational displacement amount of the feedback link from the tip of the detecting portion, the dimension r from the support pin to the output pin.
As a ratio of the dimension L up to the tip of the vibration suppressor provided in the detection section to, the rotational displacement amount of the feedback link can be proportionally increased and taken out, and the tilt amount of the valve plate can be further increased. Can be accurately detected. By providing the tilt amount detecting means, the tilt amount of the valve plate can be constantly monitored (monitored), the capacity of the hydraulic rotary machine can be controlled with higher accuracy, and the tilt amount can be controlled. It is possible to prevent the whole structure from becoming complicated by the transfer amount detecting means, and to make the whole compact to achieve miniaturization.
Has various effects.

Further, since the vibration suppressor is provided in the detection portion of the feedback link and the vibration suppressor is brought into contact with the detection rod of the tilt amount detecting means, the rotation of the cylinder block and the tilting movement of the valve plate are performed. Even if a small vibration or the like generated between the valve plate and the tilting sliding surface is transmitted to the detection part of the feedback link, this vibration is transmitted to the detection rod of the feedback link by the vibration suppressor. Can be effectively suppressed (damped).

Since the vibration suppressor can suppress (attenuate) the vibration, it is possible to reliably prevent local wear from occurring in the contact portion between the vibration suppressor and the detection rod, and thereby the tilting is performed. The displacement amount of the feedback link detected by the amount detecting means and the actual displacement amount of the feedback link corresponding to the tilt amount of the valve plate can be accurately associated with each other, and the accuracy of the tilt angle of the valve plate or the like is high. Feedback control can be performed for a long time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a variable displacement oblique shaft hydraulic pump according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken in the direction of arrows II-II in FIG.

3 is an arrow III-III in FIG. 2 showing a tilt amount sensor and the like.
It is a direction expanded sectional view.

FIG. 4 is a hydraulic circuit diagram for tilting control for tilting a valve plate or the like of a hydraulic pump.

FIG. 5 is an explanatory diagram showing a tilt angle control map stored in a storage area of a controller.

FIG. 6 is a flowchart showing a tilt angle control process of the hydraulic pump.

FIG. 7 is a vertical sectional view showing a variable displacement oblique shaft type hydraulic pump according to a conventional technique.

[Explanation of symbols]

 2 rotary shaft 3 cylinder block 4 cylinder 5 piston 6 connecting rod 7 drive disk 8 valve plate 9 tilting sliding surface 11 tilting mechanism 21 hydraulic pump 22 casing 22A casing body 22B head casing 23 control unit 25 link mechanism 26 detection pin 27 Swing link 28 Feedback link 28B Detection part 29 Support pin 30 Connecting pin 31 Spring plate (vibration suppressor) 33 Output pin 34 Sensor case 35 Tilt amount sensor (tilt amount detecting means) 35B Detection rod 38 Throttle switching valve 38A Sleeve 43 Pressure reducing valve

Front page continuation (72) Inventor Kazumasa Yuasa 650 Kazutachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd.Tsuchiura Plant (72) Inventor Shigetaka Nakamura 650 Kintachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Inside the Tsuchiura Plant (72) Inventor Yukihiro Motozawa 650 Kintatemachi, Tsuchiura City, Ibaraki Prefecture Hitachi Construction Machinery Co., Ltd.Tsuchiura Plant (72) Inventor Sotoki 650 Jintamachi, Tsuchiura City, Ibaraki Hitachi Construction Machinery Co., Ltd. Within

Claims (1)

[Claims] 1. A cylindrical casing having an end surface closed by a head casing, a rotating shaft rotatably provided in the casing, and an axial direction provided in the casing so as to rotate together with the rotating shaft. A cylinder block having a plurality of cylinders formed therein, a plurality of pistons slidably provided in the respective cylinders of the cylinder block and swingably supported by the rotary shaft via a connecting rod; Variable including a valve plate whose end surface is in sliding contact with the cylinder block and the other end surface is in slidable contact with the tilting sliding surface of the head casing, and a tilting mechanism for tilting the cylinder block together with the valve plate. In the displacement type oblique shaft type hydraulic rotating machine, in order to supply and discharge the tilting control pressure oil to the tilting mechanism, the tilting mechanism is provided on the casing at the minimum tilting side of the valve plate. A control unit and a connecting unit that is rotatably provided between the control unit and the casing via a support pin, and has a tip side that serves as a detection unit that projects toward the control unit, and a base end that projects into the casing. The feedback link, the tip side of which is rotatably connected to the connecting portion of the feedback link, and the base side of which is rotatably attached to the valve plate, and the tilt amount of the valve plate is proportional. Output pin provided in the middle of the detection part of the feedback link and a detection rod that is provided outside the control part and follows the rotational displacement of the feedback link in order to feed back to the control part in a state where the feedback link is reduced. And a tilt amount detecting means for extracting the tilt amount of the valve plate by detecting the displacement amount of the detection rod, wherein the tilting amount is detected in the detecting section of the feedback link. Detection rod abuts on, the variable capacity swash shaft type hydraulic rotary machine, characterized in that a suppressing vibration suppression member from being transmitted less vibration from the feedback link detection rod detection means.