JPH0828436A - Vaiable displacement slant shaft type hydraulic rotary machine - Google Patents

Abstract

PURPOSE:To conduct tilting angle control with high accuracy by providing a tilting amount detecting means capable of preventing the whole structure from being complicated and miniaturizing the same. CONSTITUTION:A feed-back 1ink 28 is provided through a support pin 29 between a casing 22 and control part 23 of a hydraulic pump 21. While the lower end side of the feed-back 1ink 28 is connected to a valve plate 8 through a connecting pin 30, swing 1ink 27 and respective detecting pins 26, the detecting part 28B of the feed-back 1ink 28 is allowed always to abut against a detecting rod 33B of a tilting amount sensor 33 through a patch 28C. Thus, the wear of the detecting part 28B of the feed-back 1ink 28 caused by the contact with the detecting rod 33B can be remarkably reduced and the tilting angle theta of the valve plate 8 can be accurately taken out on the basis of the turning displacement amount of the feed-back 1ink 28 detected by the tilting amount sensor 33, so that the highly accurate feed-back control can be carried out with respect to the tilting angle theta.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art FIG. 8 shows, as an example of a conventional variable displacement type oblique shaft type hydraulic rotary machine, a variable displacement type oblique shaft type hydraulic pump.

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

Reference numeral 2 denotes a rotary shaft rotatably provided in the casing main body 1A, 3 denotes a cylinder block located in the casing main body 1A and rotating together with the rotary shaft 2, and the cylinder block 3 has an axial direction in the 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 tilted curved 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 is 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 drives. 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 is 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 at 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 operating 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 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 into 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 working 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.

[0015]

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 this 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.

The feedback pin 17 for transmitting the tilt angle θ of the valve plate 8 to the controller 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 capacity oblique shaft type hydraulic rotary machine (hereinafter referred to as other conventional technology) has been proposed to reduce the size.

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 proposed, in Japanese Patent Application No. 5-346168, 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 capacity oblique shaft type hydraulic rotary machine that can directly take out the tilt angle θ of the plate.

In the variable displacement type oblique shaft type hydraulic rotary machine proposed in Japanese Patent Application No. 5-346168, it is desirable that the link mechanism is lightweight in order to improve the responsiveness to the tilting movement of the valve plate. In general, the rod of the tilt amount detecting means is generally formed of stainless steel or the like which is a non-magnetic material, whereas the rod is usually formed of an aluminum material by die casting which is easy to manufacture.

Therefore, the tip end side of the link mechanism that is always in contact with the rod is apt to wear, and the actual displacement corresponding to the displacement amount on the tip end side of the link mechanism detected by the tilt amount detecting means and the tilt angle θ of the valve plate. There is an unsolved problem in that an error occurs between the displacement amount of the link mechanism and the displacement amount on the tip side of the link mechanism, and it becomes impossible to perform a highly accurate feedback control corresponding to the tilt angle θ of the valve plate for a long period of time. .

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, the present invention can prevent the entire structure from becoming complicated and can be downsized. In addition, it is an object of the present invention to provide a variable displacement type oblique shaft hydraulic rotary machine in which the tilt amount detecting means can perform highly accurate feedback control with respect to the tilt angle for a long period of time.

[0024]

In order to solve the above-mentioned problems, a variable capacity oblique shaft type hydraulic rotating machine according to the present invention has a cylindrical casing having an end surface closed by a head casing, and a cylindrical casing. A rotary shaft that is rotatably provided and has a drive disk at the tip of the casing; and a cylinder block that is provided in the casing so as to rotate with the rotary shaft and has a plurality of cylinders formed in the axial direction. A plurality of pistons slidably provided in each cylinder of the cylinder block and swingably supported by a drive disk of the rotary shaft via a connecting rod, and one end surface of the piston slidably contacts the cylinder block, A valve plate having the other end surface slidably slidingly contacting the tilt sliding surface of the head casing, and a tilt mechanism for tilting the cylinder block together with the valve plate. Consisting of.

The features of the configuration adopted by the present invention are as follows:
In order to supply and discharge pressure oil for tilting control to the tilting mechanism, a controller provided on the casing located on the minimum tilting side of the valve plate,
A feedback link that is rotatably provided between the control unit and the casing via a support pin, and has a distal end side that serves as a detection unit that projects toward the control unit side, and a base end side that serves as a connection unit that projects into the casing. And a swing link whose front end side is rotatably connected to the connecting portion of the feedback link and whose base end side is rotatably attached to the valve plate, and which reduces the tilt amount of the valve plate proportionally. In order to feed back to the control unit in a closed state, the output pin provided in the detection unit of the feedback link and the rotational displacement of the feedback link provided outside the control unit and constantly contacting the detection unit. And a tilt amount detecting means for extracting the tilt amount of the valve plate by detecting a displacement amount of the detection rod. The detection unit is that the detection rod of inclined rotation amount detecting means is provided with a wear-resistant portion at a site in contact.

[0026]

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 tilt 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 support 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.

Moreover, since the wear resistance portion is provided in the detection portion of the feedback link at the portion of the tilt amount detection means that contacts the detection rod, the detection portion of the feedback link wears due to contact with the detection rod. Can be prevented for a long period of time, and a detection error due to wear of the detection unit can be eliminated.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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. 8 described above are designated by the same reference numerals, and the description thereof will be omitted.

First, FIGS. 1 to 6 show a first embodiment of the present invention.

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. In addition, the upper end side of the feedback link 28 serves as a detection unit 28B that protrudes upward in the housing 24 of the control unit 23 as shown in FIG. 3, and the front end side of the detection unit 28B is inserted into a sensor case 32 described later. Is extended.

Here, in order to improve the responsiveness to the tilting movement of the valve plate 8, the feedback link 28 is made of, for example, an aluminum material by die casting or the like, and the connecting portions 28A,
The detection unit 28B is integrally formed, and the overall weight is reduced.

Reference numeral 28C denotes a wear-resistant portion provided on the tip side of the detecting portion 28B of the feedback link 28, which is a wear resistant portion.
The corresponding gold 28C is, for example, high carbon chrome bearing steel (SUJ)
A tilt amount sensor 33, which will be described later, in the detection unit 28B is formed of a material having excellent wear resistance such as, for example, by encapsulating the feedback link 28 during casting, or by press fitting after the feedback link 28 is cast.
The detection rod 33B is integrally provided at a portion contacting the detection rod 33B.

Reference numeral 31 is an output pin fixed to an intermediate portion of the detecting portion 28B of the feedback link 28.
Reference numeral 1 is connected to a sleeve 38A of a throttle switching valve 38 described later. Here, the output pin 31 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 dimension L from the dowel 28C of the feedback link 28 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 is proportionally increased. It can be taken out from the tilt amount sensor 33.

Reference numeral 32 denotes a sensor case provided on the housing 24 of the control unit 23. The sensor case 32 has a detection chamber 32A from which the tip side of the detection unit 28B of the feedback link 28 projects, and an opening in the detection chamber 32A. However, a sensor mounting hole 32B into which a tilt amount sensor 33 described later is mounted is formed.

Reference numeral 33 denotes a tilt amount sensor as tilt amount detecting means provided in the sensor case 32. The tilt amount sensor 33 is a sensor body screwed into a sensor mounting hole 32B of the sensor case 32. 33A, a detection rod 33B having a base end side slidably inserted into the sensor body 33A and a tip end side protruding into the detection chamber 32A of the sensor case 32,
A detection body 33C such as a magnet provided on the base end side of the detection rod 33B and a detection unit 33D provided in the sensor body 33A and detecting the displacement amount of the detection body 33C.
Etc.

Here, the detection rod 33B 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 32B of the sensor case 32 at its axially intermediate portion. The receiving plate 34 is integrally provided. A compression spring 35 is compressed between the spring receiving plate 34 and the sensor main body 33A, and the tip end side of the detection rod 33B is in the detection chamber 32A of the sensor case 32 in accordance with the urging force of the compression spring 35. With constant pressure, it is always in contact with the dowel 28C of the feedback link 28.

Therefore, the tilt amount sensor 33 detects the tilting movement of the valve plate 8 and detects the detecting portion 28 of the feedback link 28.
When B is rotationally displaced, the detection unit 33D detects the amount of displacement of the detected body 33C that is displaced axially together with the detection rod 33B, so that the rotational displacement of the feedback link 28 is determined by the tilt angle of the valve plate 8. It is designed to be detected as θ.

Reference numeral 36 denotes a plug that closes the detection chamber 32A of the sensor case 32, and 37 denotes a lock nut in which the tilt amount sensor 33 is fastened to the sensor case 32. The lock nut 37 is on the outer peripheral side of the tilt amount sensor 33. , And the tilt amount sensor 33 is appropriately moved back and forth from the sensor case 32,
The tilt amount sensor 33 is positioned in the sensor case 32 after the position adjustment (zero point adjustment) of the detected body 33C with respect to the detection unit 33D is performed.

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 31, 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 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 denotes 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 or the like, the maximum tilt angle θmax at which the valve plate 8 can be tilted as shown in FIG.

[0049]

## 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 composed of a microcomputer or the like, and the input side of the controller 46 is connected to the tilt amount sensor 33, 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. 5 and the like 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 thereof, 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 configured as described above, and the basic operation of the variable displacement oblique shaft type hydraulic pump 21 is not significantly different from that of the above-mentioned conventional technique.

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 tilt angle θ from the tilt amount sensor 33.
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 determined to be "YES" in the 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, when the tilt angle command θs after the selection switch is determined in step 4 or step 6 as described above, the process proceeds to step 7 and the tilt angle command θ after the selection switch is executed.
The tilt angle difference Δθ between s and the actual tilt angle θ is

[0057]

[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, since the tilt angle command θs and the actual tilt angle θ substantially match, the process proceeds to step 9 and the tilt angle command at this time is θs

[0060]

## 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

[0062]

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

On the other hand, when it is determined "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.

[0064]

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

Next, as described above, step 9, 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. 6 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 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 33 is provided on the casing 22 of the first unit via the housing 24 of the control unit 23 and the sensor case 32, and the tilt displacement sensor 33 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 (monitored) by the tilt amount sensor 33, 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 33. 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.

Further, 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 the 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 31 located in the middle thereof, the tilting center of the cylinder block 3 from the attachment portion (detection pin 26) of the swing link 27 to the valve plate 8 is detected. As the ratio of the dimension R up to O and the dimension r from the support pin 29 to the output pin 31, the tilt amount of 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 of 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 31, 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, the tilt amount sensor 33 constantly detects the rotational displacement amount of the feedback link 28 by keeping the detection rod 33B in contact with the tip of the detection portion 28B of the feedback link 28 via the abutment 28C. 33
Since the configuration is taken out as the displacement amount of B, the detection unit 28 for the dimension r from the support pin 29 to the output pin 31
As the ratio of the dimension L to the tip of B (the metal 28C), the rotational displacement amount of the feedback link 28 can be proportionally increased and taken out.
The tilt angle θ of can be detected more accurately, and
The tilt amount sensor 33 can be compactly attached to the control unit 23 of the hydraulic pump 21.

Moreover, the metal member 28C is integrally provided on the detecting portion 28B of the feedback link 28, and the tilt amount sensor 3
Since the detection rod 33B of No. 3 always comes into contact with the corresponding metal 28C with a predetermined pressure, the feedback link 28 repeats the rotational displacement along with the tilting movement of the valve plate 8 during the operation of the hydraulic pump 21. Also the detection rod 33
It is possible to significantly reduce the wear of the detecting portion 28B of the feedback link 28 caused by the contact with B. Therefore, the rotational displacement amount of the detection unit 28B of the feedback link 28 detected by the displacement amount sensor 33 and the actual displacement amount of the detection unit 28B corresponding to the displacement amount of the valve plate 8 can be accurately associated. Therefore, highly accurate feedback control with respect to the tilt angle θ of the valve plate 8 and the like can be performed for a long period of time.

Furthermore, since the casing 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 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 the present embodiment, by providing the tilt amount sensor 33, 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 33
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.

Next, FIG. 7 shows a second embodiment of the present invention. In addition, in the second embodiment shown in FIG.
The same components as those in the first embodiment shown in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 51 denotes a contact plate as a wear resistant member provided on the tip side of the detecting portion 28B of the feedback link 28, and the corresponding plate 51 is wear resistant such as high carbon chromium bearing steel (SUJ). It is formed in a plate shape from an excellent material and is fixed via a bolt 53 in a state of being fitted in a notch 52 formed at the tip side of the detecting portion 28B of the feedback link 28.

Also in this example, since the detection rod 33B of the tilt amount sensor 33 contacts the detection portion 28B of the feedback link 28 via the contact plate 51, the hydraulic pump 2
In the operation of No. 1, the feedback link 28 repeats the rotational displacement in accordance with the tilting movement of the valve plate 8, so that the detection portion 28B of the feedback link 28 is significantly prevented from being worn due to contact with the detection rod 33B. can do.

Moreover, the contact plate 51 can be easily retrofitted to the existing feedback link 28 by forming the notch 52 on the tip side of the detecting portion 28B of the feedback link 28.

Other constitutions and effects of this embodiment are the same as those of the first embodiment.

In each of the above embodiments, the selection switch 4
When the operator turns 5 on, the maximum tilt angle θ at which the valve plate 8 can be tilted is limited to a target limit tilt angle θpb that is 80% of the actual maximum tilt angle θmax. However, the present invention is not limited to this, and the target limit tilt angle θpb may be appropriately set within a range of 60 to 90% of the maximum tilt angle θmax, for example.

Further, in each of the above-described embodiments, the metal member 28C or the metal plate 5 is attached to the detecting portion 28B of the feedback link 28.
Although the present invention is not limited to this, the present invention is not limited to this, and for example, the surface of the detection unit 28B with which the detection rod 33B comes into contact is subjected to a surface hardening treatment or the like so that the wear-resistant portion is May be formed.

Further, in each of the above embodiments, as the material of the metal plate 28C or the metal plate 51 provided on the detecting portion 28B of the feedback link 28, high carbon chromium bearing steel (SUJ) is used.
In addition to the above examples, cast iron (gray cast iron, white cast iron, etc.), high-strength brass, lead bronze, sintered materials, tool steel and steel materials (S45C, etc.) that have been subjected to nitrocarburizing treatment, etc. May be used.

[0085]

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 extracts 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 is obtained.
As a ratio of the dimension L up to the tip of the detection portion to the above, 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 detected more accurately. . 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. By the transfer amount detecting means, it is possible to prevent the entire structure from becoming complicated, and it is possible to achieve various effects such that the whole structure can be made compact and downsized.

Further, since the detection portion of the feedback link is provided with the wear resistant portion, the detection rod of the tilt amount detecting means comes into contact with the detection portion of the feedback link via the wear resistant portion. It is possible to effectively reduce wear of the detection unit due to contact with the detection rod, and the actual feedback link link corresponding to the displacement amount of the feedback link detection unit detected by the displacement detection unit and the displacement amount of the valve plate. It is possible to accurately correspond to the displacement amount of the detection portion, and it is possible to perform highly accurate feedback control for the tilt angle of the valve plate or the like for a long period of time.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a variable displacement oblique shaft hydraulic pump according to a first embodiment of the present invention.

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

FIG. 3 is an arrow III-III in FIG. 2 showing a tilt amount sensor, etc.
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 a flowchart showing a tilt angle control process of the hydraulic pump.

FIG. 6 is an explanatory diagram showing a tilt angle control map stored in a storage area of a controller.

FIG. 7 is an enlarged sectional view similar to FIG. 3, showing a second embodiment of the present invention.

FIG. 8 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 Detecting part 28C Metal fitting (wear resistant part) 29 Support pin 30 Connecting pin 31 Output pin 32 Sensor case 33 Tilt amount sensor (tilt amount detecting means) 33B Detection rod 34 Spring receiving plate 38 Throttle Switching valve 38A Sleeve 43 Pressure reducing valve 51 Plate (wear resistant part)

Front page continuation (72) Inventor Shigetaka Nakamura 650 Kazutachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd.Tsuchiura Plant (72) Inventor Yukihiro Motozawa 650 Kintate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Inside the factory (72) Inventor Tetsuya Sakairi 650 Kazunachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. in Tsuchiura factory (72) Inventor Sotoki 650 Jinmachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. in Tsuchiura factory

Claims (1)

[Claims] 1. A cylindrical casing having an end surface closed by a head casing, a rotary shaft rotatably provided in the casing, and a tip end of the casing serving as a drive disk, and the rotary shaft rotating together with the rotary shaft. And a cylinder block in which a plurality of cylinders are formed in the axial direction, and slidably provided in each cylinder of the cylinder block, and to a drive disk of the rotary shaft via a connecting rod. A plurality of pistons swingably supported, a valve plate having one end face slidingly contacting the cylinder block and the other end face slidingly slidingly contacting a tilting sliding face of the head casing, and the valve plate In a variable displacement oblique shaft type hydraulic rotary machine including a tilting mechanism for tilting a cylinder block, pressure oil for tilting control is supplied to and discharged from the tilting mechanism. Therefore, a control unit located on the minimum tilt side of the valve plate and provided in the casing is rotatably provided between the control unit and the casing via a support pin, and the front end side is the control unit. The feedback link is a detection part that projects toward the side of the feedback link, and the base end side is a connection part that projects into the casing. A swinging link rotatably attached, and an output pin provided in the middle of the detection unit of the feedback link for feeding back to the control unit in a state where the tilt amount of the valve plate is proportionally reduced, Provided outside the control unit,
A tilt amount detecting means for detecting a tilt amount of the valve plate by detecting a displacement amount of the detection rod by having a detection rod that follows the rotational displacement of the feedback link by constantly contacting the detection unit. And a variable resistance type oblique shaft type hydraulic rotary machine, wherein a wear resistant portion is provided at a portion of the feedback link detecting portion which comes into contact with the detection rod of the tilt amount detecting means.