JP2005351140A - Variable displacement type swash plate system hydraulic rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exhibit stable performance as a hydrostatic bearing, by excellently balancing pressing force of a swash plate by piston reaction and separation force by the hydrostatic bearing. <P>SOLUTION: The hydrostatic bearing 22 communicating with supply-discharge passages 12A and 12B via oil introducing passages 24 and 25 and holding a contact surface of both in a lubricating state, is arranged between tilting support surfaces 20A and 20B of a swash plate support 20 and leg parts 21A and 21B of the swash plate 21. This hydrostatic bearing 22 is composed of a first main hydrostatic bearing part 22A formed in one leg part 21A and communicating with the oil introducing passage 24, a second main hydrostatic bearing part 22B formed in the other leg part 21B and communicating with the oil introducing passage 25, a first auxiliary hydrostatic bearing part 22C formed in the other leg part 21B and communicating with the oil introducing passage 24, and a second auxiliary hydrostatic bearing part 22D formed in one leg part 21A and communicating with the oil introducing passage 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a variable displacement swash plate type hydraulic rotating machine suitably used as a hydraulic pump or a hydraulic motor in a work vehicle such as a wheel loader, a wheel-type hydraulic excavator, a hydraulic crane or a crawler-type hydraulic excavator, and a hydraulic crane. About.

  In general, a variable displacement swash plate type hydraulic rotating machine is used as a variable displacement swash plate hydraulic pump constituting a hydraulic source in a work vehicle such as a wheel loader or a hydraulic excavator. It is also used as a hydraulic motor for turning, traveling, etc.

  A variable capacity swash plate type hydraulic rotating machine according to this type of prior art includes a cylindrical casing, a rotary shaft rotatably provided on the casing, and the casing so as to rotate integrally with the rotary shaft. A cylinder block having a plurality of cylinders extending in the axial direction and spaced apart in the circumferential direction, a plurality of pistons fitted in the cylinders of the cylinder block so as to be reciprocally movable, and protruding from the cylinders A plurality of shoes mounted on the projecting end side of each piston, and a swash plate whose front side is a smooth surface that slidably guides each shoe and whose back side is tiltably supported by the swash plate support portion of the casing And a tilt actuator that is provided on the casing and tilts and drives the swash plate by supplying and discharging tilt control pressure from the outside.

  In this case, a pair of legs are provided on the back side of the swash plate so as to be spaced apart from each other across the rotation shaft and project in a convex curve toward the swash plate support portion of the casing. Is configured to have a pair of tilting support surfaces that are formed in a concave curved shape corresponding to the pair of leg portions and support the swash plate so as to be tiltable via the leg portions.

  The casing is provided with a pair of supply / discharge passages for supplying and discharging pressure oil into and from the cylinders of the cylinder block, and the tilt support surfaces of the leg portions of the swash plate and the swash plate support portions. A hydrostatic bearing is provided between the two. The hydrostatic bearing is configured such that a part of the pressure oil is guided from the high-pressure side supply / discharge passage of the pair of supply / discharge passages, thereby utilizing the pressure of the pressure oil to contact the contact surfaces (of the leg portions). The contact surface is maintained in a lubrication state while generating a detachment force between the convex curved surface and the tilt support surface (see, for example, Patent Document 1).

  As another conventional technique, a first hydrostatic bearing and a second static bearing which are independent from each other between a pair of leg portions formed on a swash plate and a pair of tilt support surfaces formed on a swash plate support portion. A configuration in which one pressure supply / discharge passage is communicated with the first static pressure bearing and the other supply / discharge passage is communicated with the second static pressure bearing among the pair of supply / discharge passages provided in the casing. A variable capacity swash plate type hydraulic rotating machine is also known (for example, see Patent Document 2).

  In addition, a variable capacity swash plate type hydraulic rotating machine used in a hydraulic power transmission mechanism (hereinafter referred to as HST) of a hydraulic closed circuit system is configured such that a swash plate is moved forward from a neutral position with a tilt angle of zero by a tilt actuator. Inclination drive is performed in the reverse direction, and for example, the discharge direction of the pressure oil discharged from the hydraulic pump is switched between the forward and reverse directions (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 9-166074 US Pat. No. 6,048,176 JP-A-63-259182

  By the way, in the prior art according to Patent Document 1 described above, one of the pair of supply / exhaust passages with respect to the hydrostatic bearing provided between each leg portion of the swash plate and each tilt support surface of the swash plate support portion. Since the hydraulic oil is guided from the supply / exhaust passage, the hydraulic reaction force that the swash plate receives from each piston (pressing force of the swash plate by the piston reaction force) and the divergence force by the hydrostatic bearing are Unbalance may occur with pressure fluctuations.

  In such an unbalanced state, if each leg portion of the swash plate is tilted or separated so that it slightly lifts from the tilt support surface of the swash plate support portion, the pressure oil introduced into the hydrostatic bearing is There is a problem in that it is difficult to maintain the lubrication between the leg portion of the swash plate and the tilt support surface of the swash plate support portion due to leakage to the outside.

  In addition, when the rotation direction of the rotating shaft is switched between the forward and reverse directions as in a hydraulic motor, for example, the pair of supply / exhaust passages are sequentially switched between the high pressure side and the low pressure side. In the prior art, the original function as a hydrostatic bearing cannot be maintained. Further, as in the prior art described in Patent Document 3, the swash plate is tilted and driven in the forward and reverse directions from a neutral position with a tilt angle of zero by a tilt actuator for use in HST and the like. The hydrostatic bearing of the prior art cannot be applied to the capacity type swash plate type hydraulic pump.

  On the other hand, the hydraulic rotating machine according to the prior art disclosed in Patent Document 2 includes a first hydrostatic bearing and a second independent hydrostatic bearing between a pair of legs and a pair of tilt support surfaces formed on a swash plate support. Since one of the pair of supply / discharge passages is in communication with the first static pressure bearing and the other supply / discharge passage is in communication with the second static pressure bearing. Further, the present invention can be applied to a hydraulic motor having a rotating shaft forward and reverse, a variable displacement swash plate type hydraulic pump used for HST, and the like.

  However, in this case, the hydraulic rotating machine is configured so that the detachment force by the first and second hydrostatic bearings is, for example, left and right of the rotating shaft (both sides in the radial direction) It is difficult to balance at the position), and each leg portion of the swash plate may be tilted so as to be lifted from the tilt support surface of the swash plate support portion, or may be separated. Even in this case, the pressure oil introduced into the first and second hydrostatic bearings is likely to leak to the outside, and between each leg portion of the swash plate and each tilt support surface of the swash plate support portion. There is a problem that it is difficult to maintain a lubrication state.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to satisfactorily balance the pressing force of the swash plate caused by the piston reaction force and the separation force caused by the hydrostatic bearing. An object of the present invention is to provide a variable capacity swash plate type hydraulic rotating machine capable of exhibiting stable performance as a bearing.

  Another object of the present invention can be easily applied to a hydraulic motor whose rotating shaft rotates in the forward and reverse directions, a variable displacement swash plate type hydraulic pump used for HST, etc. It is an object of the present invention to provide a variable capacity swash plate type hydraulic rotating machine which can be improved to improve productivity and reduce costs.

  In order to solve the above-described problems, the present invention is provided with a cylindrical casing provided with a swash plate support portion on one side and a pair of supply / exhaust passages on the other side, and rotatably provided in the casing. A rotary shaft, a cylinder block provided in the casing so as to rotate integrally with the rotary shaft and having a plurality of cylinders extending in the axial direction and spaced apart in the circumferential direction, and reciprocating to each cylinder of the cylinder block A plurality of pistons inserted into the cylinders, a plurality of shoes mounted on the protruding end sides of the pistons protruding from the cylinders, and a front surface side that is a smooth surface that slidably guides the shoes, and a rear surface side that is a pair. A swash plate that is supported by the swash plate support portion so as to be tiltable, and a tilting drive mechanism that tilts the swash plate by supplying and discharging tilt control pressure from the outside. Roller actuator and front A variable capacity swash plate type liquid comprising a hydrostatic bearing provided between each leg portion of the swash plate and the swash plate support portion and communicating with the supply / discharge passage to keep the contact surface of both in a lubricated state. Applied to pressure rotating machine.

  A feature of the configuration adopted by the invention of claim 1 is that the hydrostatic bearing includes a first main hydrostatic bearing provided on one leg of the pair of legs, and the pair of hydrostatic bearings. A second main hydrostatic bearing provided on the other leg of the legs, and a first auxiliary provided on the other leg apart from the second main hydrostatic bearing It is constituted by a hydrostatic bearing portion and a second auxiliary hydrostatic bearing portion provided on the one leg side away from the first main hydrostatic bearing portion.

  According to a second aspect of the present invention, the first main hydrostatic bearing portion is disposed at a position close to the resultant action point of the hydraulic reaction force that the swash plate receives from each piston on one side in the radial direction of the rotating shaft. The second main hydrostatic bearing is arranged at a position close to the resultant action point of the hydraulic reaction force that the swash plate receives from each piston on the other radial side of the rotating shaft.

  According to a third aspect of the present invention, the swash plate is provided with a through hole located between a pair of leg portions through which the rotary shaft is inserted with a gap, and the first and second main hydrostatic bearing portions. Is arranged at a position closer to the through hole than the first and second auxiliary hydrostatic bearings, and has a larger effective bearing area than the first and second auxiliary hydrostatic bearings.

  According to a fourth aspect of the present invention, the pair of leg portions are positioned farther from the rotary shaft than the first and second main hydrostatic bearing portions and the first and second auxiliary hydrostatic bearing portions. The first and second sliding bearing portions are provided in the configuration.

  On the other hand, according to the invention of claim 5, the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion communicate with one of the supply / discharge passages via an oil passage. The second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion are configured to communicate with the other supply / discharge passage of the other supply / discharge passage through another oil passage. .

  According to the invention of claim 6, the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion are in the middle of an oil passage communicating the one supply / discharge passage with the first main hydrostatic bearing portion. A throttle for independently adjusting the amount of pressure oil supplied to the main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion is provided, and the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion are provided. In the middle of the oil passage communicating with the other supply / discharge passage, the amounts of hydraulic oil supplied to the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion are adjusted independently of each other. Another diaphragm is provided.

  Further, according to the invention of claim 7, between the first main hydrostatic bearing portion, the first auxiliary hydrostatic bearing portion and the one supply / discharge passage, one side of the one supply / discharge passage is provided. The other communication side extends toward the hydrostatic bearing portion, and a common oil passage extends from the other side of the common oil passage to the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion. A branch oil passage connected individually, and between the second main hydrostatic bearing portion, the second auxiliary hydrostatic bearing portion and the other supply / exhaust passage, Other common oil passages with one side communicating with each other and extending toward the hydrostatic bearing portion, and the second main hydrostatic bearing portion and the second auxiliary static pressure are branched from each other on the other side of the common oil passage. Another branch oil passage individually connected to the bearing portion is provided.

  According to an eighth aspect of the present invention, in the middle of the common oil passage, the pressure oil supplied from the one supply / discharge passage to the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion. A common throttle for adjusting the amount is provided, and in the middle of the other common oil passage, the pressure supplied from the other supply / discharge passage to the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion. Another common throttle for adjusting the oil amount is provided.

  According to a ninth aspect of the present invention, the swash plate is configured to be driven to tilt in a forward direction and a reverse direction from a neutral position where the tilt angle is zero by the tilt actuator.

  According to a tenth aspect of the present invention, the casing includes a servo valve having a spool in a control sleeve, and controls the tilt control pressure supplied to and discharged from the tilt actuator according to a command signal from the outside. And a feedback mechanism that feedback-controls the control sleeve of the regulator following the tilting operation of the swash plate, and the feedback mechanism is an axis along the rotation axis when the swash plate is in a neutral position. When the swash plate is tilted in the forward and reverse directions, the tilting operation of the swash plate is changed to an axial displacement so that the swash plate is displaced from the initial position toward the other side in the axial direction. A conversion part that is converted and taken out, and an axial displacement that is provided between the conversion part and the control sleeve of the regulator and is taken out by the conversion part, It is constituted by a displacement transmitting unit for transmitting the over drive.

  As described above, according to the first aspect of the present invention, the hydrostatic bearing provided between each leg portion of the swash plate and the swash plate support portion is provided on one leg portion side of each leg portion. The first main hydrostatic bearing portion, the second main hydrostatic bearing portion provided on the other leg side of the leg portions, and the second main hydrostatic bearing portion spaced apart from the second main hydrostatic bearing portion. A first auxiliary hydrostatic bearing portion provided on the other leg portion side and a second auxiliary hydrostatic bearing portion provided on the one leg portion side apart from the first main hydrostatic bearing portion Therefore, even when any of the pair of supply / exhaust passages is at a high pressure, the main hydrostatic bearing portion and the auxiliary member are interposed between each leg portion of the swash plate and the swash plate support portion. The hydrostatic bearing can generate a detachment force, and the main hydrostatic bearing and the auxiliary hydrostatic bearing can counteract the hydraulic reaction force that the swash plate receives from each piston (the pressing force of the swash plate by the piston reaction force). Better balance the divergence force, it is possible to exhibit stable performance as a hydrostatic bearing.

  Accordingly, the variable displacement swash plate hydraulic rotary machine according to the present invention is a hydraulic rotary machine in which a pair of supply and discharge passages are reversibly switched between high and low pressure, for example, a hydraulic motor whose rotary shaft rotates in the forward and reverse directions, Or it can be easily applied to variable displacement swash plate type hydraulic pumps used for HST, etc., increasing versatility as variable displacement swash plate type hydraulic rotating machine, improving productivity, reducing cost, etc. Can be achieved.

  According to the second aspect of the present invention, the first and second main hydrostatic bearings are arranged at positions close to the resultant action point of the hydraulic reaction force received by each swash plate from each piston. It is possible to bring the resultant action point of the hydraulic reaction force (piston reaction force) received from each piston on the cylinder block side close to the action point of the swash plate separation force by each main hydrostatic bearing. The moment acting on the swash plate due to the separation force (for example, the moment about the axis with the resultant force acting point as a reference) can be reduced. As a result, the effective bearing area of the first and second auxiliary hydrostatic bearings can be reduced, and the entire hydraulic rotating machine including the swash plate can be reduced in size.

  According to the invention described in claim 3, the first and second main hydrostatic bearings are disposed closer to the through hole of the swash plate than the first and second auxiliary hydrostatic bearings. Since the effective bearing area is larger than that of the first and second auxiliary hydrostatic bearings, the resultant action point of the hydraulic reaction force that the swash plate receives from each piston and the main hydrostatic bearings are also provided in this case. It is possible to approach the point of action of the swash plate separation force due to. As a result, the moment acting on the swash plate by the hydraulic reaction force and the separation force can be reduced, the effective bearing area of the first and second auxiliary hydrostatic bearings can be reduced, and the swash plate can be included. The whole hydraulic rotating machine can be reduced in size.

  According to the invention of claim 4, the pair of leg portions are located farther from the rotating shaft than the first and second main hydrostatic bearing portions and the first and second auxiliary hydrostatic bearing portions. Since the first and second sliding bearing portions are provided, even when the balance of moments acting on the swash plate changes due to pressure fluctuation on the supply / exhaust passage side, the first and second sliding bearing portions The stability of the swash plate can be ensured. Moreover, by providing the first and second sliding bearing portions, the surface pressure between each leg portion of the swash plate and each tilt support surface of the swash plate support portion can be reduced, and the contact surface between the two The wear and the like can be suppressed, and the reliability and life can be improved.

  On the other hand, in the invention according to claim 5, the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion are communicated with one of the pair of supply / discharge passages, and the second Since the main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion are configured to communicate with the other supply / discharge passage, when the one supply / discharge passage has a higher pressure than the other supply / discharge passage, the swash plate The high pressure oil can be guided to the first main hydrostatic bearing on the one leg side, and the high pressure oil can be guided to the first auxiliary hydrostatic bearing on the other leg side. . Further, when the other supply / discharge passage has a higher pressure than the one supply / discharge passage, high pressure oil can be guided to the second auxiliary hydrostatic bearing on the one leg side of the swash plate, On the leg side, high pressure oil can be guided to the second main hydrostatic bearing. As a result, even when any one of the pair of supply / discharge passages is at a high pressure, the main hydrostatic bearing portion and the auxiliary hydrostatic bearing portion are provided between each leg portion of the swash plate and the swash plate support portion. Thus, the detachment force can be generated, and the detachment force at this time can be well balanced against the hydraulic reaction force that the swash plate receives from each piston, and stable performance as a hydrostatic bearing can be exhibited.

  In the invention according to claim 6, the throttle is provided in the middle of the oil passage that communicates the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion with one supply / discharge passage. The amount of pressure oil supplied to the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion can be adjusted independently of each other, and the swash plate separation force by these hydrostatic bearing portions can be adjusted according to the amount of pressure oil. Can be increased or decreased. In addition, the second main hydrostatic bearing portion is also provided in another throttle provided in the middle of an oil passage that communicates the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion with the other supply / discharge passage. And the second auxiliary hydrostatic bearing portion can be adjusted independently from each other, and the swash plate separation force by each hydrostatic bearing portion can be increased or decreased according to the pressure oil amount at this time. As a result, the moment acting on the swash plate can be balanced by the hydraulic reaction force and the detachment force from each piston, improving the stability of the swash plate and improving the reliability and life of the swash plate type hydraulic rotating machine. Can do.

  According to a seventh aspect of the present invention, a common oil passage and a branch oil passage are provided between the first main hydrostatic bearing portion, the first auxiliary hydrostatic bearing portion and the one supply / discharge passage, Since the second main hydrostatic bearing portion, the second auxiliary hydrostatic bearing portion and the other supply / discharge passage are also provided with other common oil passages and other branch oil passages, for example, each static pressure Compared to the case where an individual oil passage is provided for each bearing portion, the number of oil passages provided in the casing of the hydraulic rotating machine can be reduced, and a small and simple structure can be realized. This can improve productivity, reduce costs, and the like.

  In the invention according to claim 8, since the common throttle is provided in the middle of the common oil passage located upstream from each branch oil passage, the hole diameter (throttle diameter) of the common throttle is formed relatively large. Even so, the amount of hydraulic fluid supplied to the main hydrostatic bearing and auxiliary hydrostatic bearing through the common throttle can be adjusted well, and the common throttle can be blocked (clogged) by foreign matter such as dust. The reliability of the device can be improved. In addition, even if there are minute gaps around each hydrostatic bearing, the effect of suppressing pressure oil leakage through these gaps is obtained by a common restriction, improving the workability of the entire device and increasing productivity. Improvement, cost reduction, and the like.

  In the invention described in claim 9, since the swash plate is tilted and driven from the neutral position where the tilt angle is zero by the tilt actuator in the forward direction and in the reverse direction, the hydraulic rotary machine is set to HST or the like. Even when this hydraulic pump is connected to a hydraulic actuator using a closed hydraulic circuit, the pressure is adjusted according to the tilting direction (forward or reverse) of the swash plate. The oil discharge direction can be controlled reversibly, and when the swash plate is tilted in either the forward or reverse direction, the tilting operation of the swash plate is stabilized and the swash plate support section is maintained. Good lubrication can be maintained.

  Furthermore, in the invention described in claim 10, the feedback mechanism for performing feedback control of the control sleeve of the regulator is an initial position on one axial side along the rotation axis when the swash plate is in the neutral position, and the swash plate A conversion unit that converts the tilting operation of the swash plate into an axial displacement so as to be displaced from the initial position toward the other side in the axial direction when tilted in the forward and reverse directions; and Since it is composed of a displacement transmission part provided between the control sleeve of the regulator and transmitting the axial displacement taken out by the conversion part to the control sleeve of the regulator, the swash plate is moved in the forward and reverse directions by the tilting actuator. When the actuator is tilted, the regulator can be feedback controlled so that the regulator control sleeve is slid and displaced in the same direction as the spool. Positive, it is possible to smoothly regulator feedback control even when it is tilted in the opposite either direction. And since a regulator can be comprised by the servo valve which has the spool in the control sleeve, the structure of the whole variable capacity | capacitance type hydraulic rotating machine which performs tilt control of a swash plate can be simplified.

  Hereinafter, a variable displacement swash plate type hydraulic rotating machine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where it is applied to a traveling hydraulic circuit in a wheeled work vehicle such as a wheel loader. .

  Here, FIG. 1 to FIG. 13 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a swash plate type hydraulic pump as a variable capacity swash plate type hydraulic rotating machine. The hydraulic pump 1 includes a casing 11, a rotating shaft 13, a cylinder block 14, a plurality of cylinders 15, a piston 16 and a shoe which will be described later. 17, the valve plate 19, the swash plate support 20, the swash plate 21 and the like.

  Further, in the hydraulic pump 1, for example, a rotary shaft 13 is rotationally driven by a prime mover 2 such as a diesel engine serving as a drive source, and pressure oil is circulated in a pair of main pipes 3A and 3B as shown in FIG. The hydraulic pump 1 is connected to a hydraulic motor 5 to be described later via main pipelines 3A and 3B, and constitutes a so-called hydraulic closed circuit 4.

  Reference numeral 5 denotes a traveling hydraulic motor as a hydraulic actuator, and the hydraulic motor 5 is connected to wheels 7 and 7 of a wheeled work vehicle via a reduction gear 6, for example. The hydraulic motor 5 is configured to drive and drive the work vehicle by rotationally driving the wheels 7 when the hydraulic oil from the hydraulic pump 1 is supplied and discharged via the main pipelines 3A and 3B.

  Reference numeral 11 denotes a cylindrical casing that serves as an outer shell of the hydraulic pump 1. The casing 11 includes a cylindrical casing body 11A and a front casing in which both end sides of the casing body 11A are closed as shown in FIGS. 11B and the rear casing 11C.

  Further, as shown in FIG. 3, an opening 11D and a drain passage 11E are formed on the outer peripheral side of the casing body 11A, and these opening 11D and the drain passage 11E serve as a valve of a regulator 34 described later in the casing body 11A. The housing 35 is always in communication. A translation bar 44 described later is slidably attached to the opening 11D of the casing body 11A via a guide member 45 and the like. The casing 11 is a so-called drain chamber and is connected to a tank 47 described later.

  Here, in the front casing 11B located on one side of the casing body 11A, a swash plate support 20, which will be described later, is provided facing the back side of the swash plate 21, as shown in FIGS. The rear casing 11C located on the other side of the casing body 11A is provided with a pair of supply / discharge passages 12A, 12B, and the supply / discharge passages 12A, 12B are connected to the main pipelines 3A, 3B shown in FIG. Is.

  Reference numeral 13 denotes a rotating shaft rotatably provided in the casing 11, and the rotating shaft 13 is rotatably supported by a front casing 11B and a rear casing 11C via bearings, and protrudes in the axial direction from the front casing 11B. The projecting end 13 </ b> A side is rotationally driven by the prime mover 2 shown in FIG. 1.

  Reference numeral 14 denotes a cylinder block provided in the casing 11 so as to rotate integrally with the rotary shaft 13. The cylinder block 14 includes a plurality of cylinders 15, 15,. Is provided.

  16, 16,... Are pistons slidably inserted into the respective cylinders 15 of the cylinder block 14. The pistons 16 are arranged when a swash plate 21 described later is tilted in the forward and reverse directions. As the cylinder block 14 rotates, the cylinder 15 is reciprocated to repeat the suction stroke and the discharge stroke.

  17, 17,... Are shoes provided on each piston 16, and each shoe 17 is disposed on one end side (projecting end side) of the piston 16 projecting from the cylinder 15 of the cylinder block 14 in the axial direction of the rotary shaft 13. Each is swingably attached.

  Reference numeral 18 denotes an annular shoe presser for holding each shoe 17 against the swash plate 21. The shoe presser 18 holds the shoe 17 toward a smooth surface 21C of the swash plate 21 described later as shown in FIGS. This is to compensate for the sliding displacement of each shoe 17 on the smooth surface 21C of the swash plate 21 so as to draw an annular locus.

  A valve plate 19 is located in the casing 11 and is provided between the rear casing 11C and the cylinder block 14. The valve plate 19 is in sliding contact with the end face of the cylinder block 14, and the cylinder block 14 is connected to the rotary shaft 13. It is supported so that it can rotate together. The valve plate 19 is formed with a pair of supply / discharge ports 19A, 19B having an eyebrow shape as shown in FIGS. 3 and 4, and these supply / discharge ports 19A, 19B are connected to the supply / discharge passage 12A of the rear casing 11C. , 12B.

  The supply / discharge ports 19A and 19B of the valve plate 19 are intermittently communicated with the cylinders 15 when the cylinder block 14 rotates, and are sucked into the cylinders 15 from the one supply / discharge passage 12A (or 12B) side. The hydraulic oil is pressurized by the piston 16 and has a function of discharging the pressurized oil in a high pressure state in each cylinder 15 from the other supply / discharge passage 12B (or 12A).

  Reference numeral 20 denotes a swash plate support as a swash plate support provided around the rotary shaft 13 and provided in the front casing 11B. The swash plate support 20 has, for example, the rotary shaft 13 interposed therebetween as shown in FIG. A pair of tilt support surfaces 20A and 20B are provided at positions on both the left and right sides, and the swash plate 21 is tiltably supported.

  The tilt support surfaces 20A and 20B of the swash plate support 20 are formed in a concave curved shape corresponding to leg portions 21A and 21B of the swash plate 21 described later, and the swash plate 21 is illustrated in FIGS. It is guided so as to be tiltable (slidable) in the directions of arrows A and B around the tilt center C. Further, the swash plate support 20 is formed with a part of branch oil passages 24B, 24C, 25B, and 25C described later.

  A swash plate 21 is provided in the casing 11 so as to be tiltable via a swash plate support 20, and on the back side of the swash plate 21, as shown in FIGS. 2 to 7, the swash plate support 20 is provided. A pair of left and right leg portions 21A and 21B projecting in a convex curve shape toward the tilt support surfaces 20A and 20B are provided. The leg portions 21A and 21B of the swash plate 21 are slidable on the tilting support surfaces 20A and 20B of the swash plate support 20 which is spaced apart, for example, in the left and right directions across the rotation shaft 13 and has a concave curved shape. Is to be fitted.

  On the other hand, the front surface side of the swash plate 21 is a smooth surface 21C that guides each shoe 17 slidably as shown in FIGS. Further, the swash plate 21 is provided with a through hole 21D that extends through in the thickness direction of the swash plate 21. The through hole 21D is located between the leg portions 21A and 21B, and the rotary shaft 13 is inserted with a gap therebetween. It is.

  Here, the leg portions 21A and 21B of the swash plate 21 are formed as arc surfaces having a radius R from the tilt center C as shown in FIGS. 6 to 10, and the tilt center C is the axis O− of the rotary shaft 13. It is arranged on O. The swash plate 21 is provided with tilt actuators 32 and 33, which will be described later, in the forward direction (arrow A direction) and the reverse direction (arrow B direction) from the neutral position where the tilt angle is zero as shown in FIGS. The displacement (pressure oil discharge amount) of the hydraulic pump 1 is variably controlled according to the tilt angle θ at this time.

  The swash plate 21 receives a hydraulic reaction force (piston reaction force) from each piston 16 that rotates integrally with the cylinder block 14 around the rotation shaft 13, and the resultant forces f1 and f2 of the hydraulic reaction force are applied to the action point. (Hereinafter referred to as resultant force action points k1, k2) varies with the rotation of the cylinder block 14 so as to draw a character "∞" as illustrated in FIG. In this case, when the swash plate 21 is tilted in the forward direction from the neutral position, it receives a hydraulic reaction force at the position of the resultant action point k1, and when it is tilted in the reverse direction from the neutral position, the resultant action point k2. The hydraulic reaction force is received at the position of.

  Reference numeral 22 denotes a hydrostatic bearing provided between the tilt support surfaces 20A and 20B of the swash plate support 20 and the legs 21A and 21B of the swash plate 21, and the hydrostatic bearing 22 is provided, for example, in the rear casing 11C. When pressure oil is guided from the pair of supply / discharge passages 12A and 12B as described later, a separation force (hydraulic pressure) is generated between the tilt support surfaces 20A and 20B and the leg portions 21A and 21B. The contact surface is kept in a lubricated state.

  The hydrostatic bearing 22 is a first main hydrostatic pressure provided on the convex curved surface side of one leg 21A at a position close to the through hole 21D of the swash plate 21 as shown in FIGS. 22 A of bearing parts, 2nd main hydrostatic bearing part 22B provided in the convex-curved surface side of the other leg part 21B in the position near 21D of through holes, and 2nd main hydrostatic bearing part 22B, and spaced apart from this 2nd main hydrostatic bearing part 22B The first auxiliary hydrostatic bearing portion 22C provided on the convex curved surface side of the leg portion 21B and the first auxiliary hydrostatic bearing portion 22A provided on the convex curved surface side of the leg portion 21A apart from the first main hydrostatic bearing portion 22A. 2 auxiliary hydrostatic bearings 22D.

  Of these hydrostatic bearing portions 22A to 22D, the first main hydrostatic bearing portion 22A and the first auxiliary hydrostatic bearing portion 22C are connected to one supply / discharge passage 12A via an oil guide passage 24 described later. The second main hydrostatic bearing portion 22B and the second auxiliary hydrostatic bearing portion 22D are connected to the other supply / discharge passage 12B via an oil guide passage 25 described later.

  In this case, the first and second main hydrostatic bearings 22A and 22B are formed as concave grooves extending in the directions indicated by arrows A and B along the convex curved surfaces of the legs 21A and 21B as shown in FIG. The planar shape is an elongated rectangular shape as shown in FIG. Further, the first and second auxiliary hydrostatic bearings 22C and 22D are located on the left and right sides (diameters) of the first and second main hydrostatic bearings 22A and 22B with reference to the through hole 21D of the swash plate 21. It is arranged at a position on the outside of the direction).

  The first and second auxiliary hydrostatic bearings 22C and 22D are also substantially parallel to the first and second main hydrostatic bearings 22A and 22B along the convex curved surfaces of the legs 21B and 21A (FIG. 8). 9 is formed as a concave groove extending in the direction of arrows A and B), and the planar shape thereof is an elongated rectangular shape as shown in FIG. However, the first and second auxiliary hydrostatic bearings 22C and 22D have the groove lengths (groove lengths in the directions indicated by arrows A and B) and the groove widths in the left and right directions in the first and second directions. It is formed smaller than the main hydrostatic bearing portions 22A and 22B.

  That is, the first main hydrostatic bearing portion 22A is close to the resultant action point k1 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 on one radial direction side (the right side in FIG. 9) of the through hole 21D. Are disposed at a distance La from the action point k1. Further, the second main hydrostatic bearing 22B is located at a position near the resultant action point k2 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 on the other radial side of the through hole 21D (left side in FIG. 9). These are disposed at a distance Lb from the action point k2.

  Further, the first auxiliary hydrostatic bearing portion 22C has a distance Lc (from the resultant action point k1 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 on the other radial side of the through hole 21D (left side in FIG. 9). It is arranged at a position where Lc> La). Further, the second auxiliary hydrostatic bearing 22D has a distance Ld (from the resultant action point k2 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 on one side in the radial direction of the through hole 21D (the right side in FIG. 9). Ld> Lb).

  The first and second main hydrostatic bearings 22A and 22B are closer to the through hole 21D than the first and second auxiliary hydrostatic bearings 22C and 22D as shown in FIGS. The effective bearing areas Sa and Sb of the main hydrostatic bearings 22A and 22B are arranged such that the effective bearing areas Sc and Sd of the auxiliary hydrostatic bearings 22C and 22D satisfy the relationship according to the following equations (4) and (8). It is formed larger than.

  23A and 23B are first and second sliding bearing portions provided on the leg portions 21A and 21B of the swash plate 21, and the first and second sliding bearing portions 23A and 23B are shown in FIGS. As shown in FIG. 9, on both the left and right sides of the through hole 21D, the main static pressure bearing portions 22A and 22B and the auxiliary static pressure bearing portions 22C and 22D are disposed at positions farther from the through hole 21D. That is, the sliding bearing portions 23A and 23B are formed in a convex curved shape at positions that become edges on the left and right sides of the leg portions 21A and 21B.

  The sliding bearing portions 23A and 23B are slidably in contact with the tilt support surfaces 20A and 20B of the swash plate support 20 with a small surface pressure, and the leg portions 21A and 21B of the swash plate 21 are swash plate support 20. Is smoothly compensated together with the hydrostatic bearing portions 22A to 22D.

  Reference numerals 24 and 25 denote oil guide passages for guiding the pressure oil to the hydrostatic bearing portions 22A to 22D of the hydrostatic bearing 22, and the oil guide passages 24 and 25 are formed as shown in FIGS. 22A-22D is connected to a pair of supply / discharge passages 12A, 12B. One oil guide passage 24 is provided between the one supply / discharge passage 12A, the first main hydrostatic bearing portion 22A, and the first auxiliary hydrostatic bearing portion 22C, and the other oil guide passage 25 is The other supply / discharge passage 12B is provided between the second main hydrostatic bearing 22B and the second auxiliary hydrostatic bearing 22D.

  Here, one oil guide passage 24 is provided in the casing 11, one side communicates with the supply / discharge passage 12 </ b> A, and the other side faces the first main hydrostatic bearing portion 22 </ b> A and the first auxiliary hydrostatic bearing portion 22 </ b> C. The extended common oil passage 24A and the branch oil passage 24B branched from each other on the other side of the common oil passage 24A and individually connected to the first main hydrostatic bearing portion 22A and the first auxiliary hydrostatic bearing portion 22C. , 24C.

  The branch oil passages 24B and 24C of the oil guide passage 24 extend from the front casing 11B side of the casing 11 so as to branch into the swash plate support 20, and the tilt support surfaces 20A of the swash plate support 20 are provided. On the 20B side, the first main hydrostatic bearing portion 22A and the first auxiliary hydrostatic bearing portion 22C are open.

  The other oil guide passage 25 is provided in the casing 11 and has one side communicating with the supply / discharge passage 12B and the other side extending toward the second main hydrostatic bearing portion 22B and the second auxiliary hydrostatic bearing portion 22D. A common oil passage 25A, and branched oil passages 25B branched from each other on the other side of the common oil passage 25A and individually connected to the second main hydrostatic bearing portion 22B and the second auxiliary hydrostatic bearing portion 22D, 25C.

  The branch oil passages 25B and 25C of the oil guide passage 25 extend in a branched manner from the front casing 11B side of the casing 11 into the swash plate support 20, and the tilt support surfaces 20B of the swash plate support 20 are provided. On the 20A side, the second main hydrostatic bearing 22B and the second auxiliary hydrostatic bearing 22D are open.

  Reference numerals 26 and 27 denote common throttles provided in the middle of the common oil passages 24A and 25A. One of the common throttles 26 and 27 is connected to the supply / discharge passage 12A as shown in FIGS. The amount of pressure oil supplied in common to the first main hydrostatic bearing portion 22A and the first auxiliary hydrostatic bearing portion 22C is adjusted according to the throttle diameter (hole diameter). The other common throttle 27 is configured to reduce the amount of pressure oil supplied in common to the second main hydrostatic bearing 22B and the second auxiliary hydrostatic bearing 22D from the supply / discharge passage 12B. ) To adjust.

  The common throttles 26 and 27 have a larger diameter than individual throttles 28 to 31 described later, and main hydrostatic bearings 22A and 22B and auxiliary hydrostatic bearings 22C and 22D from the supply / discharge passages 12A and 12B. Coarse adjustment of the amount of pressure oil supplied to As a result, the main hydrostatic bearing portions 22A and 22B and the auxiliary hydrostatic bearing portions 22C and 22D can suppress the occurrence of large variations in the amount of pressure oil supplied.

  28 and 29 are throttles provided in the middle of the branch oil passages 24B and 25B (hereinafter referred to as individual throttles 28 and 29), and 30 and 31 are other throttles provided in the middle of the branch oil passages 24C and 25C (hereinafter referred to as Individual diaphragms 30, 31). These individual throttles 28 to 31 have a narrower diameter than the common throttles 26 and 27, and after being roughly adjusted by the common throttles 26 and 27, the individual throttles 28 to 31 are statically passed through the branch oil passages 24B, 25B, 24C, and 25C. The amount of pressure oil supplied to the pressure bearing portions 22A to 22D is finely adjusted independently of each other.

  That is, the individual throttle 28 finely adjusts the amount of pressure oil supplied to the first main hydrostatic bearing 22A via the branch oil passage 24B individually, and the individual throttle 29 is the second oil via the branch oil passage 25B. The amount of pressure oil supplied to the main hydrostatic bearing 22B is finely adjusted individually. The individual throttle 30 individually finely adjusts the amount of pressure oil supplied to the first auxiliary hydrostatic bearing 22C via the branch oil passage 24C, and the individual throttle 31 is secondly adjusted via the branch oil passage 25C. The amount of pressure oil supplied to the auxiliary hydrostatic bearing portion 22D is finely adjusted individually.

  Reference numerals 32 and 33 denote a pair of tilting actuators for tilting the swash plate 21. The tilting actuators 32 and 33 are arranged on the outer side in the radial direction of the cylinder block 14 as shown in FIG. 2, FIG. 3, FIG. The cylinder holes 32A and 33A formed in the casing main body 11A are slidably inserted into the cylinder holes 32A and 33A, and the hydraulic chambers 32B and 33B are interposed between the cylinder holes 32A and 33A. The tilting pistons 32C and 33C defining the above and the springs 32D and 33D disposed in the hydraulic pressure chambers 32B and 33B and constantly biasing the tilting pistons 32C and 33C toward the swash plate 21 side. Has been.

  Here, the tilting actuators 32 and 33 are disposed at positions facing each other in the radial direction of the cylinder block 14 with respect to the casing body 11A, and the swash plate 21 is moved in the directions indicated by arrows A and B by the tilting pistons 32C and 33C. Tilt drive. That is, the hydraulic pressure chambers 32B and 33B of the tilt actuators 32 and 33 are connected to control pipes 50B and 50A, which will be described later, as shown in FIGS. 3 and 10, and the tilt control pressure is supplied and discharged.

  Then, when the tilting piston 33C extends from the cylinder hole 33A as shown in FIG. 7 and the tilting piston 32C contracts into the cylinder hole 32A as shown in FIG. 7, the swash plate 21 is moved by the tilting piston 33C. It is tilted and driven in the direction A (positive direction). When the tilting piston 32C extends from the cylinder hole 32A and the tilting piston 33C contracts into the cylinder hole 33A, the swash plate 21 tilts in the direction indicated by the arrow B (reverse direction) by the tilting piston 32C. It is driven.

  Reference numeral 34 denotes a regulator as a capacity control valve for supplying and discharging the tilt control pressure to the tilt actuators 32 and 33. The regulator 34 is provided outside the casing body 11A as shown in FIG. 10 includes a valve housing 35, a control sleeve 36, a spool 37, a hydraulic pilot portion 38, a valve spring 39, and the like, which will be described later, and has a spool 37 in the control sleeve 36 as shown in FIG. It is constituted by a valve.

  Here, as shown in FIG. 3, the valve housing 35 of the regulator 34 is provided with supply / discharge ports 35A, 35B for tilt control pressure, and the supply / discharge port 35A is connected to a pilot pump 46 via a control line 48A described later. Connected to the discharge side. The supply / discharge port 35B is connected to a control line 48B described later. The valve housing 35 of the regulator 34 is provided in a liquid-tight manner on the outer surface of the casing 11, and the control sleeve 36, the spool 37, and the like are parallel to the rotary shaft 13 (axis OO shown in FIG. 10). It is arranged to extend.

  Reference numeral 36 denotes a cylindrical control sleeve slidably fitted in the valve housing 35. The control sleeve 36 has a translation bar 44 (described later) on the outer circumference on one side in the axial direction using a plurality of fixing screws or the like. It is integrally connected and follows the movement of the translation bar 44 (translational movement along the axial direction of the rotary shaft 13) and slides in the valve housing 35 in the axial direction (directions D and E in FIG. 6). It will be displaced.

  A spool 37 is slidably inserted into the control sleeve 36. The spool 37 is slidably displaced in the axial direction of the valve housing 35 on the inner peripheral side of the control sleeve 36, thereby supplying and discharging. The port 35B is selectively communicated with or shut off from the supply / discharge port 35A or the drain passage 11E.

  A hydraulic pilot portion 38 is provided on the valve housing 35 and is located on one axial side of the spool 37. The hydraulic pilot portion 38 drives the spool 37 in the axial direction against a valve spring 39 described later. The command pressure is supplied through a command pressure line 53 described later.

  Then, the plunger 38A of the hydraulic pilot portion 38 receives the command pressure from the command pressure line 53 as a pilot pressure, and thereby the spool 37 is slid in the axial direction within the valve housing 35 in accordance with the pilot pressure, The regulator 34 shown in FIG. 10 is switched from the neutral position (A) to the switching positions (B) and (C).

  Reference numeral 39 denotes a valve spring disposed between the other axial side of the spool 37 and the valve housing 35. The valve spring 39 constantly urges the spool 37 toward the hydraulic pilot portion 38, for example, FIG. 10 is returned to the neutral position (A).

  Reference numeral 40 denotes a feedback mechanism that feedback-controls the regulator 34 in accordance with the tilting operation of the swash plate 21. The feedback mechanism 40 includes a side surface of the swash plate 21 and a control sleeve 36 of the regulator 34 as shown in FIGS. And a later-described converter 41, a translation bar 44, and the like.

  Reference numeral 41 denotes a conversion unit that converts the tilting operation of the swash plate 21 into an axial displacement, and the conversion unit 41 includes a cam groove 42 and a cam follower 43 described later. Then, the conversion unit 41 converts the tilting operation of the swash plate 21 into axial displacement as described later, and generates a translational movement (translation) along the axis OO of the rotating shaft 13 in a translation bar 44 described later. It is something to be made.

  Reference numeral 42 denotes a cam groove having a cam surface for converting the tilting movement of the swash plate 21 into the axial displacement of the cam follower 43. The cam groove 42 is formed on the side surface (the other side) of the swash plate 21 as shown in FIGS. It is constituted by a concave groove provided in a substantially letter-like shape on the side surface of the leg portion 21B, and is disposed at a position separated from the tilt center C of the swash plate 21. The cam groove 42 has a groove width corresponding to the outer diameter of the roller portion 43A so that a roller portion 43A of a cam follower 43 described later is slidably (rotatably) inserted. .

  Here, as shown in FIGS. 10 and 11, the cam groove 42 is an intermediate groove portion serving as a neutral position sliding contact portion with which the roller portion 43 </ b> A of the cam follower 43 is in sliding contact when the swash plate 21 is in a neutral position with a zero tilt angle. 42A, the lower inclined groove portion 42B as a forward sliding portion to which the roller portion 43A slides when the swash plate 21 is tilted from the neutral position in the arrow A direction (forward direction), and the swash plate 21 is neutral. It is comprised by 42 C of upper side inclination groove parts as a reverse direction slidable contact part which roller part 43A slidably contacts when it inclines in the arrow B direction (reverse direction) from a position.

  Of the groove portions 42A to 42C of the cam groove 42, the intermediate groove portion 42A has a dimension Ra that is the largest distance along the axis OO of the rotary shaft 13 from the tilt center C when the swash plate 21 is in the neutral position. It is arranged at a position (Ra <R). The lower inclined groove portion 42B extends obliquely downward from the position of the intermediate groove portion 42A toward the tilt center C, and the upper inclined groove portion 42C extends from the intermediate groove portion 42A toward the tilt center C. It is formed so as to extend obliquely upward.

  That is, the cam groove 42 is formed on the side surface of the swash plate 21 as a concave groove bent in a substantially V shape or “<” shape at the position of the intermediate groove portion 42A, and includes a lower inclined groove portion 42B and an upper inclined groove portion 42C. Are symmetrical to each other so as to expand downward and upward with respect to the axis OO from the position of the intermediate groove 42A.

  The lower inclined groove portion 42B and the upper inclined groove portion 42C extend to the positions of later-described points G1, H1 shown in FIG. 11, and these points G1, H1 are separated from the tilt center C of the swash plate 21. They are arranged at positions separated by the dimension Rb. The dimension Rb in this case is set to a dimension (Rb <Ra <R) smaller than the dimension Ra from the tilt center C to the intermediate groove portion 42A.

  Reference numeral 43 denotes a cam follower provided in sliding contact with the cam groove 42. The cam follower 43 is integrally provided on one side in the length direction of a translation bar 44 described later as shown in FIG. It has a roller portion 43A that can rotate (spin) along the wall surface (cam surface).

  The cam follower 43 converts the tilting operation of the swash plate 21 into an axial displacement as will be described later by the roller portion 43A being slidably engaged with the cam groove 42 on the swash plate 21 side. The translation bar 44 generates a translational motion (translation) along the axis OO.

  In this case, the roller portion 43A of the cam follower 43 that engages with the cam groove 42 on the swash plate 21 side is disposed together with the translation bar 44 at the initial position shown in FIG. 11 when the swash plate 21 is in the neutral position. It is located on a line FF perpendicular to the axis OO of the shaft 13. At this time, the roller portion 43 </ b> A of the cam follower 43 is disposed at the position most retracted (retracted in the direction of arrow E in FIG. 10) along the axis OO of the rotation shaft 13.

  Further, when the swash plate 21 is tilted from the neutral position in the direction indicated by the arrow A (positive direction) as shown in FIGS. 7 and 12, the tilt angle θ becomes an angle α (θ = α). 43 roller parts 43A are moved to the point G1 shown in FIG. 12 while being in sliding contact with the lower inclined groove part 42B of the cam groove 42. As a result, the roller portion 43A of the cam follower 43 is translated (translational movement) to the position of the line GG together with the translation bar 44, and the rotary shaft 13 by the dimension a with respect to the line FF at the initial position described above. It is displaced in the axial direction.

  On the other hand, when the swash plate 21 is tilted in the arrow B direction (reverse direction) as shown in FIG. 13 from the neutral position and the tilt angle θ becomes an angle β (θ = β), the roller of the cam follower 43 The portion 43A is moved to the position of the point H1 shown in FIG. 13 while being in sliding contact with the upper inclined groove portion 42C of the cam groove 42. As a result, the roller portion 43A of the cam follower 43 is translated together with the translation bar 44 to the position of the line HH, and is displaced in the axial direction of the rotary shaft 13 by the dimension b with respect to the line FF at the initial position. The

  When the swash plate 21 is tilted in the forward and reverse directions with the same tilt angle θ (for example, angles α and β), the angles α and β corresponding to the tilt angle θ of the swash plate 21 are opposite to each other. The angles have the same direction (α = β), and the dimensions a and b corresponding to the axial displacement at this time are set to the same value (a = b).

  44 is a translation bar as a translation member constituting the displacement transmission part of the feedback mechanism 40, and the translation bar 44 can be slid into the opening 11D of the casing body 11A via a guide member 45 described later as shown in FIG. And performs a translational motion along the axial direction of the rotary shaft 13 (axis OO shown in FIG. 10). As shown in FIG. 3, the translation bar 44 extends in the radial direction of the rotating shaft 13 in the casing 11 and also extends outward in the radial direction with respect to the control sleeve 36. 36.

  Here, the translation bar 44 is provided with a cam follower 43 on one side in the length direction, and is given a translational motion along the axis OO of the rotary shaft 13 integrally with the cam follower 43. 3 and 4, the translation bar 44 has a bifurcated fixing portion 44A that sandwiches the control sleeve 36 from the outside in the radial direction on the other side in the length direction. The fixing portion 44A includes a plurality of fixing screws or It is fixed to the outer peripheral side of the control sleeve 36 by fixing means such as a rivet.

  That is, the translation bar 44 is held in a fixed state with respect to the control sleeve 36 at a certain angle (for example, 90 degrees which is vertical). The translation bar 44 allows the roller portion 43A of the cam follower 43 to be displaced in the axial direction along the axis OO of the rotating shaft 13, but the roller portion 43A moves in a direction orthogonal to the axis OO. It is the structure which regulates.

  Thus, when the swash plate 21 is tilted in the directions indicated by arrows A and B in FIG. 2, the translation bar 44 shown in FIG. 3 is moved together with the cam follower 43 along with the cam follower 43 according to the tilting operation of the swash plate 21. Translate in the axial direction. Then, the parallel movement of the translation bar 44 is transmitted as it is to the control sleeve 36 of the regulator 34 on the fixed portion 44A side, and the control sleeve 36 is moved to the axis OO of the rotary shaft 13 in the directions indicated by arrows D and E in FIG. The feedback control of the regulator 34 is performed by being displaced along.

  45 is a guide member provided so as to cover the opening 11D of the casing 11 shown in FIG. 3, and the guide member 45 supports the intermediate portion in the longitudinal direction of the translation bar 44 so as to be movable or slidable. It is possible to prevent the bar 44 from swinging upward and downward (for example, the circumferential direction of the cylinder block 14) and the like, and to vibrate due to backlash and the like, so that the translation bar 44 is smooth in the axial direction of the rotary shaft 13. It is intended to compensate for parallel movement (translational movement).

  46 is a pilot pump that generates a tilt control pressure, and the pilot pump 46 is rotated together with the hydraulic pump 1 by the prime mover 2 shown in FIG. The pressure oil for tilt control is discharged into the control line 48A.

  In this case, the pressure of the pressure oil discharged from the pilot pump 46 is maintained at a pressure sufficiently lower than the discharge pressure of the hydraulic pump 1 by the low-pressure relief valve 49. The control line 48B is provided between a supply / discharge port 35B of the regulator 34 and a forward / reverse switching valve 51 described later.

  50A and 50B are other control lines for supplying and discharging the tilt control pressure to and from the hydraulic chambers 32B and 33B of the tilt actuators 32 and 33. The control lines 50A and 50B are as shown in FIGS. Are connected to control lines 48A and 48B through a forward / reverse switching valve 51 described later.

  Reference numeral 51 denotes a forward / reverse switching valve as a direction switching valve provided between the control lines 48A and 48B and the control lines 50A and 50B. The forward / reverse switching valve 51 is configured as shown in FIGS. The left and right solenoid portions 51A and 51B are provided. For example, when an operator manually operates a switching lever (not shown) in the cab, the vehicle is moved from the stop position (a) to the forward position (b) or the reverse position ( c).

  In a state where the forward / reverse switching valve 51 is switched from the stop position (a) to the forward position (b), the tilt control pressure from the pilot pump 46 is controlled in response to the operator depressing a travel pedal 52A described later. The fluid is supplied to the hydraulic chamber 33B of the tilting actuator 33 through the pipes 48A and 50A.

  At this time, the tilt control pressure is discharged from the hydraulic pressure chamber 32B of the tilt actuator 32 to the tank 47 side via the control lines 50B and 48B, the regulator 34, and the like. Thereby, the tilting piston 33C of the tilting actuator 33 drives the swash plate 21 to tilt in the direction indicated by the arrow A in FIG.

  On the other hand, when the forward / reverse switching valve 51 is switched from the stop position (a) to the reverse position (c), the tilt control pressure from the pilot pump 46 is transmitted through the control lines 48A and 50B in response to the depression operation of the travel pedal 52A. It is supplied to the hydraulic chamber 32B of the tilt actuator 32. Further, the tilting control pressure is discharged from the hydraulic pressure chamber 33B of the tilting actuator 33 to the tank 47 side via the control lines 50A, 48B, the regulator 34, etc., so that the tilting piston of the tilting actuator 32 is discharged. 32C drives the swash plate 21 to tilt in the direction of arrow B in FIG.

  Thus, the forward / reverse switching valve 51 is provided between the regulator 34 and the tilting actuators 32 and 33, and is switched from the stop position (a) of the vehicle to the forward position (b) or the reverse position (c). Thus, the supply / discharge direction of the tilt control pressure with respect to the tilt actuators 32 and 33 is switched, and the swash plate 21 is tilt-driven from the neutral position to the forward direction and the reverse direction according to the tilt control pressure.

  Reference numeral 52 denotes a travel operation valve as a command means provided on the cab side of the wheel type vehicle. The travel operation valve 52 is provided with a travel pedal 52A corresponding to an accelerator pedal of the vehicle. When the operator of the vehicle depresses the travel pedal 52A, pilot pressure as a command signal is supplied to the hydraulic pilot section 38 of the regulator 34 through the command pressure line 53, and the travel speed of the vehicle is variably adjusted as will be described later. Is.

  The traveling hydraulic circuit of the wheel type work vehicle including the variable displacement swash plate hydraulic pump 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, in a state where the forward / reverse switching valve 51 shown in FIG. 10 is disposed at the stop position (a), the control lines 50A and 50B are both connected to the control line 48A, and the hydraulic chambers 32B of the tilt actuators 32 and 33 are connected. , 33B are kept at an equal pressure state, so that the swash plate 21 is held at a neutral position with a zero tilt angle.

  For this reason, even if the rotary shaft 13 is driven to rotate by the prime mover 2 and the cylinder block 14 is rotated, each piston 16 does not reciprocate within each cylinder 15 of the cylinder block 14, and the supply / discharge passage of the hydraulic pump 1. 12A and 12B are in the same pressure state as each other, and supply and discharge of the pressure oil through the main lines 3A and 3B to the hydraulic motor 5 shown in FIG. 1 are stopped.

  Next, when the vehicle operator switches the forward / reverse switching valve 51 from the stop position (a) to the forward position (b), the tilt control pressure from the pilot pump 46 in response to the operator depressing the travel pedal 52A. Is supplied to the hydraulic pressure chamber 33B of the tilting actuator 33 through the control lines 48A and 50A.

  At this time, since the pilot pressure is supplied from the command pressure line 53 toward the hydraulic pilot portion 38 of the regulator 34 by the depression operation of the travel pedal 52A, the spool 37 is brought to the pilot pressure in the valve housing 35 of the regulator 34. In response to the displacement in the axial direction, the regulator 34 is switched from the neutral position (A) shown in FIG. 10 to the switching position (C).

  Therefore, the control line 48B is connected to the tank 47 via the regulator 34, the drain chamber in the casing 11, and the like, and the tilt control pressure is supplied from the inside of the hydraulic pressure chamber 32B of the tilt actuator 32 to the control line. It is discharged to the tank 47 side through 50B and 48B, the regulator 34 and the like. Thereby, the tilting piston 33C of the tilting actuator 33 drives the swash plate 21 to tilt in the direction of arrow A in FIG.

  In a state where the swash plate 21 is tilted in the direction indicated by the arrow A, the cylinder block 14 rotates integrally with the rotary shaft 13, whereby each piston 16 has a stroke amount corresponding to the tilt angle θ (displacement volume). Thus, the reciprocating motion is repeated in each cylinder 15 of the cylinder block 14. For this reason, the hydraulic pump 1 discharges pressurized oil from the supply / discharge passage 12A side, for example, while sucking oil into each cylinder 15 from the supply / discharge passage 12B side.

  As a result, in the traveling hydraulic closed circuit 4 shown in FIG. 1, the pressure oil flows along the direction of the arrow A1 in the main pipes 3A and 3B, and the traveling hydraulic motor 5 is supplied and discharged by the pressure oil supply and discharge. It can be rotated. Then, the rotation output of the hydraulic motor 5 is transmitted to the wheels 7 and 7 of the wheel type work vehicle via the speed reducer 6, and the wheels 7 are driven to rotate, for example, the tilt angle θ of the work vehicle in the forward direction. Can be driven at a speed corresponding to.

  On the other hand, when the forward / reverse switching valve 51 is switched from the stop position (a) to the reverse position (c), the tilt control pressure from the pilot pump 46 is transmitted through the control lines 48A and 50B in response to the depression operation of the travel pedal 52A. It is supplied to the hydraulic chamber 32B of the tilt actuator 32. Further, the tilting control pressure is discharged from the hydraulic chamber 33B of the tilting actuator 33 to the tank 47 side via the control lines 50A and 48B, the regulator 34, and the like, and is tilted by the tilting piston 32C of the tilting actuator 32. The plate 21 can be driven to tilt in the direction indicated by the arrow B in FIG.

  In this case, pressure oil can be circulated along the direction indicated by arrow B1 in the traveling hydraulic closed circuit 4 shown in FIG. 1, and the traveling hydraulic motor 5 is driven to rotate in the same direction. For example, the work vehicle can be driven to travel at a speed corresponding to the tilt angle θ in the reverse direction while transmitting the rotation output of the hydraulic motor 5 to the wheels 7 and 7 of the wheel type work vehicle via the speed reducer 6.

  Here, when the swash plate 21 is tilted in the positive direction from the neutral position, one of the pair of supply / discharge passages 12A and 12B has a high pressure on the one supply / discharge passage 12A side, and the swash plate 21 is shown in FIG. The resultant force f1 of the hydraulic reaction force is received from each piston 16 at the position of the resultant force application point k1.

  However, the first main hydrostatic bearing 22A provided on the leg 21A of the swash plate 21 and the first auxiliary hydrostatic bearing 22C provided on the leg 21B are connected to the oil guide passage from the supply / discharge passage 12A. Since the high pressure oil is guided through the 24 common oil passages 24A and the branch oil passages 24B and 24C, the tilt support surfaces 20A and 20B of the swash plate support 20 and the leg portions 21A and 21B of the swash plate 21 are connected. In the meantime, a separation force fa and a separation force fc are generated.

  The first main static pressure bearing portion 22A is disposed at a position at a distance La from the resultant action point k1 of the hydraulic reaction force received from each piston 16 by the swash plate 21 as shown in FIG. The pressure bearing portion 22C is disposed at a position that is a distance Lc (Lc> La) from the resultant action point k1.

  For this reason, with respect to the resultant force f1 of the hydraulic reaction force received by each swash plate 21 from each piston 16, the deviation force fa by the first main hydrostatic bearing portion 22A and the deviation force fc by the first auxiliary hydrostatic bearing portion 22C are obtained. By setting the relationship satisfying the following equations (1) to (4), the resultant reaction force f1 of the hydraulic reaction force and the divergence forces fa and fc are balanced, and the tilt support surfaces 20A and 20B of the swash plate support 20 and the oblique The contact surface between the leg portions 21A and 21B of the plate 21 can be maintained in a lubricated state.

  That is, the deviation force fa by the first main hydrostatic bearing portion 22A and the deviation force fc by the first auxiliary hydrostatic bearing portion 22C are, for example, the swash plate 21 tilted in the positive direction from the neutral position. Is set so as to satisfy the following relationship with respect to the resultant force f1 of the hydraulic reaction force received from.

  Further, the resultant force f1 received by the swash plate 21 at this time is expressed by the following equation from the relationship between the pressure P caused by the hydraulic reaction force and the pressure receiving area S1.

  Assuming that the same pressure P is applied to the first main hydrostatic bearing portion 22A and the first auxiliary hydrostatic bearing portion 22C, the main hydrostatic bearing portion 22A has an effective bearing area Sa. Since the auxiliary hydrostatic bearing 22C has an effective bearing area Sc (Sc <Sa), the following relationship is derived from the equation (1).

  Further, the divergence force fa (effective bearing area Sa) by the first main hydrostatic bearing portion 22A acts on the position at a distance La from the resultant action point k1, and the detachment force fc by the first auxiliary hydrostatic bearing portion 22C. (Effective bearing area Sc) acts at a position at a distance Lc from the resultant action point k1. For this reason, the moments of the separation forces fa and fc with reference to the resultant action point k1 are set so as to satisfy the following relationship.

  As a result, the deviation force fa of the main hydrostatic bearing portion 22A and the deviation force fc of the auxiliary hydrostatic bearing portion 22C can be balanced against the resultant force f1 of the hydraulic reaction force received by each swash plate 21 from each piston 16. Further, it is possible to prevent the leg portions 21A and 21B of the swash plate 21 from being tilted so as to be lifted from the tilting support surfaces 20A and 20B of the swash plate support 20 or separated from each other.

  As a result, it is possible to suppress the pressure oil introduced into the hydrostatic bearing portions 22A and 22C from leaking to the outside, and the leg portions 21A and 21B of the swash plate 21 and the tilt support surfaces 20A and 20B of the swash plate support 20 Can be maintained in a lubrication state. Further, the tilting operation of the swash plate 21 can be stabilized, and the tilt driving force by the tilt actuators 32 and 33 can be reduced.

  On the other hand, when the swash plate 21 is tilted in the reverse direction from the neutral position, the swash plate 21 receives the resultant force f2 of the hydraulic reaction force from each piston 16 at the position where the resultant force application point k2 shown in FIG. Then, with respect to the resultant force f2 at this time, the deviation force fb by the second main hydrostatic bearing portion 22B and the deviation force fd by the second auxiliary hydrostatic bearing portion 22D are set so as to satisfy the following relationship. .

  Further, the resultant force f2 received by the swash plate 21 at this time is expressed by the following equation from the relationship between the pressure P caused by the hydraulic reaction force and the pressure receiving area S2.

  Assuming that the same pressure P acts on the second main hydrostatic bearing portion 22B and the second auxiliary hydrostatic bearing portion 22D, the main hydrostatic bearing portion 22B has an effective bearing area Sb. Since the auxiliary hydrostatic bearing portion 22D has an effective bearing area Sd (Sd <Sb), the following relationship is derived from the equation (5).

  Further, the detachment force fb (effective bearing area Sb) by the second main hydrostatic bearing 22B acts at a position that is a distance Lb from the resultant action point k2, and the detachment force fd by the second auxiliary hydrostatic bearing 22D. (Effective bearing area Sd) acts at a position at a distance Ld from the resultant force application point k2. For this reason, the moments of the separation forces fb and fd with reference to the resultant action point k2 are set so as to satisfy the following relationship.

  As a result, the deviation force fb of the main hydrostatic bearing portion 22B and the deviation force fd of the auxiliary hydrostatic bearing portion 22D can be balanced against the resultant force f2 of the hydraulic reaction force that the swash plate 21 receives from each piston 16. Further, it is possible to prevent the leg portions 21A and 21B of the swash plate 21 from being tilted so as to be lifted from the tilting support surfaces 20A and 20B of the swash plate support 20 or separated from each other.

  As a result, even when the swash plate 21 is tilted in the reverse direction from the neutral position, it is possible to suppress the leakage of the hydraulic oil introduced into the static pressure bearing portions 22B and 22D to the outside. 21A and 21B and the tilt support surfaces 20A and 20B of the swash plate support 20 can be maintained in a lubricated state, and the tilting operation of the swash plate 21 can be stabilized, and the tilt driving force by the tilt actuators 32 and 33 can also be obtained. Can be small.

  By the way, the traveling speed when the vehicle moves forward or backward is determined by the discharge amount (flow rate) of the pressure oil by the hydraulic pump 1, and this discharge amount is increased or decreased according to the tilt angle θ of the swash plate 21. Unless the regulator 34, which is a capacity control valve, is feedback-controlled according to the tilt angle θ of the swash plate 21, the tilt angle θ of the swash plate 21 (that is, the travel speed of the vehicle) is depressed by the travel pedal 52A. It is difficult to control with stability alone.

  Therefore, in the present embodiment, the feedback mechanism 40 is provided between the control sleeve 36 of the regulator 34 and the side surface of the swash plate 21, and the swash plate 21 is in either the forward or reverse direction from the neutral position where the tilt angle is zero. Even when being tilted, the regulator 34 is configured to feedback control the regulator 34 by following the tilting operation of the swash plate 21.

  The feedback mechanism 40 includes a cam groove 42 that is formed on a side surface of the swash plate 21 (side surface of the leg portion 21B) and is a concave groove that is bent in a substantially square shape with respect to the axis OO of the rotation shaft 13. A cam follower 43 having a roller portion 43A that is in sliding contact with the cam groove 42 and converting the tilting operation of the swash plate 21 into an axial displacement, and an axial displacement of the rotary shaft 13 taken out by the cam follower 43 in the axial direction. The translation bar 44 includes a translation bar 44 that translates, and transmits the axial displacement of the cam follower 43 to the control sleeve 36 by a fixing portion 44A on the distal end side.

  In this case, as shown in FIG. 11, the cam groove 42 on the swash plate 21 side is the dimension that is the largest distance along the axis OO of the rotary shaft 13 from the tilt center C when the swash plate 21 is in the neutral position. An intermediate groove portion 42A disposed at a position of Ra (Ra <R), a lower inclined groove portion 42B extending obliquely downward from the position of the intermediate groove portion 42A toward the tilt center C, and an intermediate groove portion 42A The upper inclined groove portion 42C extends obliquely upward in a direction approaching the tilting center C from the center of the swash plate 21, and the entire cam groove 42 is substantially V-shaped or “kaku” at the position of the intermediate groove portion 42A on the side surface of the swash plate 21. It is formed as a concave groove bent in the shape of "".

  Further, since the fixed portion 44A side of the translation bar 44 is held, for example, in a vertically fixed state with respect to the control sleeve 36, the roller portion 43A of the cam follower 43 is orthogonal to the axis OO of the rotating shaft 13. Movement (position shift) in the direction is restricted, and only axial displacement along the axis OO is allowed.

  The roller portion 43A of the cam follower 43 is disposed at a position where the swash plate 21 is in sliding contact with the intermediate groove portion 42A when the swash plate 21 is in the neutral position with a zero tilt angle. ), The roller portion 43A slides along the lower inclined groove portion 42B, and when the swash plate 21 is tilted from the neutral position in the arrow B direction (reverse direction), the roller portion 43A is inclined upward. It slides along the groove 42C.

  Therefore, when the swash plate 21 is tilted from the neutral position in the arrow A direction (positive direction) as shown in FIG. 12, and the tilt angle θ is an angle α (θ = α), the roller portion of the cam follower 43 43A is slid along the lower inclined groove portion 42B of the cam groove 42 to the position of the point G1, and translates the translation bar 44 together with the cam follower 43 to the position of the line GG shown in FIG. be able to.

  The line FF when the translation bar 44 is at the initial position is at a position of the dimension Ra from the tilt center C of the swash plate 21, and the line GG passing through the point G1 is dimensioned from the tilt center C. Since it is in the position of Rb, the axial displacement amount when the translation bar 44 is displaced in the axial direction of the rotary shaft 13 from the line FF of the initial position to the position of the line GG is a dimension according to the following equation (9). It can be obtained as a.

  On the other hand, when the swash plate 21 is tilted in the arrow B direction (reverse direction) as shown in FIG. 13 from the neutral position and the tilt angle θ is an angle β (θ = β), the roller portion of the cam follower 43 43A is slid along the upper inclined groove portion 42C of the cam groove 42 to the position of the point H1, and the translation bar 44 can be translated together with the cam follower 43 to the position of the line HH shown in FIG.

  In this case, the line HH passing through the point H1 is also located at the dimension Rb from the tilt center C, so that the translation bar 44 rotates from the initial position line FF to the position of the line HH. The amount of axial displacement at the time of displacement in the 13 axial directions can be obtained as a dimension b according to the following equation (10).

  In this way, the roller portion 43A of the cam follower 43 that is in sliding contact with the cam groove 42 on the swash plate 21 side tilts the swash plate 21 when the swash plate 21 tilts in the forward and reverse directions together with the cam groove 42. The movement can be converted into an axial displacement (for example, displacement of dimensions a and b) of the translation bar 44 along the axis OO of the rotary shaft 13 and can be taken out. The translation bar 44 can transmit the axial displacement at this time to the control sleeve 36 as the same axial displacement by the fixing portion 44A.

  Therefore, according to the present embodiment, even when the variable displacement swash plate hydraulic pump 1 is connected to the hydraulic motor 5 using the hydraulic closed circuit 4 illustrated in FIG. The plate 21 can be tilted from the neutral position in the forward direction and the reverse direction to control the discharge amount (flow rate) of the pressure oil in both directions, and the tilt angle of the swash plate 21 can be adjusted even when the vehicle is traveling forward or backward. The corresponding speed control can be performed smoothly.

  In addition, the regulator 34 serving as a capacity control valve can be configured by a hydraulic servo valve having a simple structure having a spool 37 in the control sleeve 36. Therefore, the tilt actuators 32 and 33, the regulator 34, and the feedback mechanism 40 are included. The entire structure of the tilt control device can be simplified, the number of parts can be reduced, and workability during assembly can be improved. Further, since the forward / reverse switching valve 51 is provided between the regulator 34 and the tilt actuators 32, 33, the entire structure of the tilt control device including the regulator 34 can be simplified as compared with the prior art. It is possible to improve performance and reduce costs.

  Further, the tilt control device of the hydraulic pump 1 is not limited to the hydraulic closed circuit 4 illustrated in FIG. 1, and can supply and discharge pressure oil to a hydraulic actuator such as a hydraulic motor even when applied to a so-called hydraulic open circuit. Therefore, it can be applied to both a hydraulic closed circuit and an open circuit, and it is possible to improve versatility, improve productivity, reduce costs, and the like.

  Further, in the present embodiment, the hydrostatic bearing 22 (hydrostatic bearing portions 22A to 22D) is disposed between the tilt support surfaces 20A and 20B of the swash plate support 20 and the leg portions 21A and 21B of the swash plate 21. ), And high pressure oil is introduced into the hydrostatic bearings 22A to 22D from the pair of supply / discharge passages 12A and 12B, so that the inclined support surfaces 20A and 20B and the legs 21A and 21B are interposed between them. Deviation forces (for example, divergence forces fa, fb, fc, fd in FIG. 5) can be generated, and the contact surfaces of both can be maintained in a lubricated state.

  The swash plate 21 can balance the separation forces fa and fc (separation forces fb and fd) at this time with the resultant force f1 (the resultant force f2) of the hydraulic reaction force received from the pistons 16 by static pressure. With the hydrostatic bearing 22 including the bearing portions 22A to 22D, stable performance as a hydrostatic bearing can be obtained.

  Thus, the application target of the present invention is not limited to the variable displacement swash plate hydraulic pump 1 used for HST or the like, but a pair of supply / discharge passages such as a hydraulic motor whose rotating shaft rotates in the forward and reverse directions is reversible. In particular, it can be easily applied to a hydraulic rotating machine or the like that switches between high and low pressure, and it is possible to improve versatility, improve productivity, reduce costs, and the like.

  Further, the first and second main hydrostatic bearings 22A and 22B are arranged at positions close to the resultant action points k1 and k2 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 as shown in FIG. Therefore, the resultant action points k1 and k2 can be brought close to the action points of the detachment forces fa and fb by the main hydrostatic bearings 22A and 22B. , Fb can reduce the moment acting on the swash plate 21 (for example, the moment about the axis with reference to the resultant action points k1, k2). Thus, the effective bearing areas Sc and Sd of the first and second auxiliary hydrostatic bearing portions 22C and 22D can be reduced, and the entire hydraulic pump 1 including the swash plate 21 can be downsized.

  Further, the leg portions 21A and 21B of the swash plate 21 are provided with the first and second sliding bearing portions 23A and 23B at positions farther from the rotating shaft 13 than the auxiliary hydrostatic bearing portions 22D and 22C. Even when the balance of moments acting on the swash plate 21 changes due to pressure fluctuation or the like on the supply / discharge passages 12A, 12B side, the stability of the swash plate 21 is ensured by the first and second sliding bearing portions 23A, 23B. be able to.

  Moreover, the first and second sliding bearing portions 23A and 23B are slidably contacted with the tilt support surfaces 20A and 20B of the swash plate support 20 with a small surface pressure, and the leg portions 21A and 21B of the swash plate 21 are slidable. And the inclined support surfaces 20A and 20B of the swash plate support 20 can be reduced, wear on the contact surfaces of the two can be suppressed, and reliability and life can be improved.

  On the other hand, a common oil passage 24A and branch oil passages 24B and 24C are provided between the first main hydrostatic bearing portion 22A, the first auxiliary hydrostatic bearing portion 22C, and the one supply / discharge passage 12A. Between the main hydrostatic bearing portion 22B, the second auxiliary hydrostatic bearing portion 22D and the other supply / discharge passage 12B, there are provided another common oil passage 25A and branch oil passages 25B and 25C, and a common oil passage. Common apertures 26 and 27 are provided in the middle of 24A and 25A.

  For this reason, even if the hole diameters (throttle diameters) of the common throttles 26 and 27 are formed to be relatively large, the main hydrostatic bearing parts 22A and 22B and the auxiliary hydrostatic bearing parts 22C and 22D are connected via the common throttles 26 and 27. The amount of pressure oil to be supplied can be adjusted satisfactorily, the possibility that the common throttles 26 and 27 are blocked (clogged) by foreign matters such as dust can be reduced, and the reliability of the apparatus can be improved.

  Further, even when there are minute gaps around the static pressure bearing portions 22A to 22D, the effect of suppressing the leakage of the pressure oil through these gaps by the common throttles 26 and 27 is obtained, and the workability of the entire apparatus is obtained. To improve productivity and reduce costs.

  In addition, since the individual throttles 28, 29, 30, 31 are provided in the middle of the branch oil passages 24B, 24C, 25B, 25C, the main hydrostatic bearings 22A, 22B and the auxiliary hydrostatic bearings. The amount of pressure oil supplied to 22C, 22D can be adjusted independently of each other, and the divergence forces fa, fb, fc, fd of the swash plate 21 by these hydrostatic bearing portions 22A, 22B, 22C, 22D are individually throttled 28. It can be easily increased or decreased according to the amount of pressure oil through ~ 31.

  Accordingly, the swash plate 21 is subjected to the resultant force f1, f2 of the hydraulic reaction force received from each piston 16 by the swash plate 21 and the divergence forces fa, fb, fc, fd by the static pressure bearing portions 22A, 22B, 22C, 22D. The balance of the acting moments can be increased, the operability and stability of the swash plate 21 can be improved, and the reliability and life of the swash plate hydraulic pump 1 can be increased.

  Next, FIG. 14 to FIG. 16 show a second embodiment of the present invention. The feature of this embodiment is that a main hydrostatic bearing portion and an auxiliary hydrostatic bearing portion provided on a leg portion of a swash plate are An oil passage for guiding pressure oil to the auxiliary hydrostatic bearing portion is formed in the swash plate so as to be spaced apart from each other in the circumferential direction along the convex curved surface of the leg portion. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, reference numeral 61 denotes a variable displacement swash plate hydraulic pump employed in the present embodiment. The hydraulic pump 61 is substantially the same as the hydraulic pump 1 described in the first embodiment. The cylinder block 14, the plurality of cylinders 15, the piston 16, the shoe 17, the valve plate 19, the swash plate support 20, the swash plate 21, and the like.

  Reference numeral 62 denotes a hydrostatic bearing provided between the tilt support surfaces 20A and 20B of the swash plate support 20 and the leg portions 21A and 21B of the swash plate 21, and the hydrostatic bearing 62 is the same as that of the first embodiment. In substantially the same manner as the hydrostatic bearing 22 described above, the pressure oil is guided from the pair of supply / discharge passages 12A and 12B, thereby causing a detachment force (hydraulic pressure) between the tilt support surfaces 20A and 20B and the legs 21A and 21B. ) And the contact surfaces of both are kept in a lubricated state.

  However, the static pressure bearing 62 in this case is the first main static pressure provided on the convex curved surface side of the one leg portion 21A at a position close to the through hole 21D of the swash plate 21 as shown in FIGS. 62 A of bearing parts, the 2nd main hydrostatic bearing part 62B provided in the convex curved surface side of the other leg part 21B in the position close | similar to the through hole 21D, and a leg part from this 2nd main hydrostatic bearing part 62B The first auxiliary hydrostatic bearings 62C and 62C provided on the convex curved surface side of the leg 21B and spaced apart in the circumferential direction of 21B, and from the first main hydrostatic bearing 62A to the leg 21B in the circumferential direction The second auxiliary hydrostatic bearings 62D and 62D are provided so as to be spaced apart from each other and provided on the convex curved surface side of the leg 21A.

  The first and second main hydrostatic bearings 62A and 62B are formed as concave grooves extending in the directions of arrows A and B along the convex curved surfaces of the legs 21A and 21B as shown in FIG. The planar shape is rectangular as shown in FIG. The first auxiliary hydrostatic bearings 62C and 62C are arranged so as to sandwich the second main hydrostatic bearing 62B from both sides in the circumferential direction along the convex curved surface of the leg 21B. On the convex curved surface of 21B, it is formed as an ellipse-shaped concave groove extending thinly in the left and right directions.

  The second auxiliary hydrostatic bearings 62D, 62D are arranged so as to sandwich the first main hydrostatic bearing 62A from both sides in the circumferential direction along the convex curved surface of the leg 21A. On the convex curved surface of 21A, it is formed as an ellipse-shaped concave groove extending thinly in the left and right directions.

  Of these hydrostatic bearings 62A to 62D, the first main hydrostatic bearing 62A and the first auxiliary hydrostatic bearings 62C and 62C are supplied and discharged through an oil guide path 64 described later. The second main hydrostatic bearing 62B and the second auxiliary hydrostatic bearings 62D, 62D are connected to the passage 12A and are connected to the other supply / discharge passage 12B via an oil guide passage 65 described later. It is.

  The first main hydrostatic bearing 62A is close to the resultant action point k1 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 on one side in the radial direction of the through hole 21D (the right side in FIG. 16). Has been placed. Further, the second main hydrostatic bearing 62B is located at a position near the resultant action point k2 of the hydraulic reaction force that the swash plate 21 receives from each piston 16 on the other radial side of the through hole 21D (left side in FIG. 16). Has been placed.

  Even in the present embodiment, the effective bearing areas of the main hydrostatic bearing portions 62A and 62B and the auxiliary hydrostatic bearing portions 62C and 62D are the same as the main hydrostatic bearing portions 22A and 22A described in the first embodiment. 22B and the auxiliary static pressure bearing portions 22C and 22D are set to have substantially the same area.

  63A and 63B are first and second sliding bearing portions provided on the leg portions 21A and 21B of the swash plate 21, and the first and second sliding bearing portions 63A and 63B are the same as those in the first embodiment. The sliding bearing portions 23A and 23B are configured in substantially the same manner.

  64 and 65 are oil guide passages for guiding the pressure oil to the hydrostatic bearing portions 62A to 62D of the hydrostatic bearing 62. The oil guide passages 64 and 65 are formed as shown in FIGS. 62A to 62D are connected to the pair of supply / discharge passages 12A and 12B. One oil guide passage 64 is provided between the one supply / discharge passage 12A, the main hydrostatic bearing portion 62A, and the auxiliary static pressure bearing portion 62C, and the other oil guide passage 65 is provided in the other supply / discharge passage. 12B is provided between the main hydrostatic bearing 62B and the auxiliary hydrostatic bearing 62D.

  Here, one oil guide passage 64 has a first oil passage 64A, one side communicating with the supply / discharge passage 12A and the other side extending toward the main hydrostatic bearing 62A, and the main hydrostatic bearing 62A. In order to communicate with the pressure bearing portions 62C and 62C, the second oil passage 64B, the third oil passage 64C, and the fourth oil passages 64D and 64D are formed in the swash plate 21.

  In this case, as shown in FIGS. 15 and 16, the second oil passage 64B has one side opened into the first main hydrostatic bearing 62A, and the other side is connected to the fourth oil passage 64C via the third oil passage 64C. The oil passages 64D and 64D communicate with one side. The fourth oil passages 64D and 64D have a V-shape and are branched from each other, and the tip ends thereof open to the first auxiliary hydrostatic bearings 62C and 62C.

  Further, as shown in FIGS. 14 to 16, the other oil guide passage 65 has a first oil passage 65A, one side communicating with the supply / discharge passage 12B and the other side extending toward the second main hydrostatic bearing 62B. In order to connect the second main hydrostatic bearing portion 62B to the auxiliary hydrostatic bearing portions 62D and 62D, the second oil passage 65B, the third oil passage 65C and the fourth oil passage bored in the swash plate 21 are provided. Oil passages 65D and 65D.

  In this case, as shown in FIG. 15 and FIG. 16, the second oil passage 65B has one side opened into the second main hydrostatic bearing 62B, and the other side is connected to the fourth oil passage 65C via the third oil passage 65C. The oil passages 65D and 65D communicate with one side. The fourth oil passages 65D and 65D have a V-shape and are branched from each other, and the tip ends thereof open to the second auxiliary hydrostatic bearing portions 62D and 62D.

  Reference numerals 66 and 67 denote throttles provided in the middle of the first oil passages 64A and 65A. One of the throttles 66 and 67 is connected to the first main static passage from the supply / discharge passage 12A as shown in FIG. The amount of pressure oil supplied to the pressure bearing portion 62A is adjusted according to the throttle diameter (hole diameter). The other throttle 67 adjusts the amount of pressure oil supplied from the supply / discharge passage 12B to the second main hydrostatic bearing 62B in accordance with the throttle diameter (hole diameter).

  Thus, also in the present embodiment configured as described above, the tilting operation of the swash plate 21 can be stabilized, and substantially the same operational effects as those of the first embodiment can be obtained.

  However, in the present embodiment, since the oil passages 64A to 64D and the oil passages 65B to 65D are provided in the swash plate 21, the oil passages 64A and 65A provided in the casing 11 and the swash plate support 20 are provided. The pipe structure can be simplified, and workability during production and processing can be improved.

  In the first embodiment, the case where the main static pressure bearing portions 22A and 22B and the auxiliary static pressure bearing portions 22C and 22D are provided on the legs 21A and 21B of the swash plate 21 has been described as an example. However, the present invention is not limited to this, and the first and second main hydrostatic bearings and the first and second auxiliary hydrostatic bearings are connected to, for example, the tilt support surfaces 20A and 20B of the swash plate support 20. It is good also as a structure provided in.

  In addition, the first and second main hydrostatic bearings and the first and second auxiliary hydrostatic bearings are connected to the tilt support surfaces 20A and 20B of the swash plate support 20 and the legs 21A and 21A of the swash plate 21, respectively. It is good also as a structure provided over both 21B. This point is the same for the second embodiment.

  Further, in the first embodiment, an example in which the conversion portion 41 of the feedback mechanism 40 that feedback-controls the regulator 34 by following the tilting operation of the swash plate 21 is constituted by the cam groove 42 and the cam follower 43 is taken as an example. And explained. However, the present invention is not limited to this. For example, as described in Japanese Patent Application No. 2004-000529 previously proposed by the present applicant, the conversion portion of the feedback mechanism may be a convex portion provided on the side surface of the swash plate. The engaging portion and an engaged portion such as a slider portion provided on the translation bar may be used.

  In each of the above embodiments, the traveling operation valve 52 is used as an external command means, and a pilot pressure corresponding to the depression operation amount of the traveling pedal 52A is supplied as a command signal to the regulator 34 (63). Explained. However, the present invention is not limited to this. For example, the hydraulic pilot section 38 of the regulator 34 is configured by an electromagnetic proportional solenoid or the like, and an electric signal corresponding to the depression operation amount of the travel pedal 52A is output from the external command means as a command signal. It is good also as a structure output as these.

  In each of the above embodiments, the variable displacement swash plate hydraulic pumps 1 and 61 have been described as an example applied to a traveling hydraulic circuit in a wheeled work vehicle such as a wheel loader. However, the present invention is not limited to a traveling hydraulic circuit, but can be applied to a closed hydraulic circuit for various purposes such as a turning hydraulic circuit.

  Further, in each of the above-described embodiments, the case where the variable displacement swash plate type hydraulic rotating machine is applied to the swash plate type hydraulic pumps 1 and 61 has been described as an example. However, the application target of the present invention is not limited to the variable displacement swash plate hydraulic pump, and may be applied to, for example, a variable displacement swash plate hydraulic motor.

  In addition, the work vehicle to which the present invention is applied is not limited to a wheel loader, but may be a work vehicle such as a wheel-type hydraulic excavator, a wheel-type hydraulic crane, a bulldozer, or a lift truck, or a work vehicle such as a crawler-type hydraulic excavator. Applicable.

1 is a traveling hydraulic circuit diagram of a wheeled work vehicle provided with a variable displacement swash plate hydraulic pump according to a first embodiment of the present invention. It is a longitudinal cross-sectional view of the hydraulic pump shown in FIG. It is the longitudinal cross-sectional view which looked at the hydraulic pump from the arrow III-III direction in FIG. It is an expanded sectional view of the hydraulic pump shown in FIG. It is sectional drawing which expands and shows the swash plate support body and swash plate in FIG. 4 with a hydrostatic bearing part. It is an expanded sectional view which looked at the state in which a swash plate exists in a neutral position from the arrow VI-VI direction in FIG. It is sectional drawing in the same position as FIG. 6 which shows the state which the swash plate inclined in the positive direction. It is a perspective view which expands and shows the swash plate in FIG. It is the rear view which looked at the swash plate of FIG. 8 from the back surface side. It is a circuit block diagram which shows the inclination control apparatus of the swash plate by 1st Embodiment. It is a front view which shows the swash plate in FIG. 10 with a tilting piston. It is a front view which shows the state which inclined the swash plate in FIG. 11 to the positive direction. It is a front view which shows the state which inclined the swash plate in FIG. 11 in the reverse direction. It is a longitudinal cross-sectional view in the same position as FIG. 3 which shows the hydraulic pump by 2nd Embodiment. It is a perspective view which expands and shows the swash plate in FIG. It is the rear view which looked at the swash plate of FIG. 15 from the back surface side.

Explanation of symbols

1,61 Hydraulic pump (variable displacement swash plate type hydraulic rotating machine)
2 prime mover 4 hydraulic closed circuit 5 hydraulic motor 11 casing 13 rotating shaft 14 cylinder block 15 cylinder 16 piston 17 shoe 19 valve plate 20 swash plate support (swash plate support)
20A, 20B Tilt support surface 21 Swash plate 21A, 21B Leg portion 21C Smooth surface 21D Through hole 22, 62 Hydrostatic bearing 22A, 62A First main hydrostatic bearing portion 22B, 62B Second main hydrostatic bearing portion 22C 62C First auxiliary hydrostatic bearing portion 22D, 62D Second auxiliary hydrostatic bearing portion 23A, 63A First sliding bearing portion 23B, 63B Second sliding bearing portion 24, 25, 64, 65 Oil guide path 24A , 25A Common oil passage 24B, 24C, 25B, 25C Branch oil passage 26, 27 Common restriction 28, 29, 30, 31 Individual restriction 32, 33 Tilt actuator 32B, 33B Hydraulic chamber 32C, 33C Tilt piston 34 Regulator 35 Valve housing 36 Control sleeve 37 Spool 38 Hydraulic pilot part 39 Valve spring 40 Feedback mechanism 41 Conversion part 42 Cam groove ( Beam surface)
43 Cam Follower 44 Translation Bar (Displacement Transmitter)
44A Fixed portion 45 Guide member 46 Pilot pump 47 Tank 51 Forward / reverse switching valve (direction switching valve)
52 Traveling control valve (command means)
52A Traveling pedal 53 Command pressure line 64A, 64B, 64C, 64D Oil path 65A, 65B, 65C, 65D Oil path 66, 67 Restriction

Claims (10)

A cylindrical casing provided with a swash plate support on one side and a pair of supply / exhaust passages on the other side, a rotary shaft rotatably provided on the casing, and a rotary shaft that rotates integrally with the rotary shaft A cylinder block having a plurality of cylinders extending in the axial direction and spaced apart in the circumferential direction, a plurality of pistons removably fitted in the cylinders of the cylinder block, and the cylinders A plurality of shoes mounted on the protruding end side of each piston protruding from the front surface, and the front side becomes a smooth surface that slidably guides each shoe, and the back side becomes a pair of legs and tilts toward the swash plate support portion. A swash plate that is rotatably supported; a tilt actuator that is provided in the casing and tilts and drives the swash plate by supplying and discharging a tilt control pressure from the outside; each leg of the swash plate; Installed between the swash plate support In is the variable capacity swash plate type hydraulic rotary machine comprising a hydrostatic bearing for holding the contact surfaces of both to communicate with the supply and discharge passage lubrication,
The hydrostatic bearing includes a first main hydrostatic bearing provided on one leg of the pair of legs and a second provided on the other leg of the pair of legs. A main hydrostatic bearing part, a first auxiliary hydrostatic bearing part provided on the other leg part side apart from the second main hydrostatic bearing part, and the first main hydrostatic bearing part A variable capacity swash plate type hydraulic rotating machine characterized in that it is constituted by a second auxiliary hydrostatic bearing provided on the one leg side apart from the first.   The first main hydrostatic bearing is disposed at a position close to the resultant action point of the hydraulic reaction force received by the swash plate from each piston on one side in the radial direction of the rotating shaft, and the second main hydrostatic bearing. 2. The variable capacity swash plate hydraulic rotation according to claim 1, wherein the portion is arranged at a position near the resultant action point of the hydraulic reaction force received from each piston by the swash plate on the other radial side of the rotation shaft. Machine.   The swash plate is provided with a through hole located between a pair of leg portions through which the rotating shaft is inserted with a gap, and the first and second main hydrostatic bearing portions are the first and second auxiliary members. The variable capacity type according to claim 1 or 2, wherein the variable capacity type is configured to be disposed closer to the through hole than the hydrostatic bearing portion and to have an effective bearing area larger than that of the first and second auxiliary hydrostatic bearing portions. Swash plate type hydraulic rotating machine.   The pair of legs includes first and second sliding bearings at positions farther from the rotary shaft than the first and second main hydrostatic bearings and the first and second auxiliary hydrostatic bearings. The variable capacity swash plate type hydraulic rotating machine according to claim 1, 2 or 3, wherein the portion is provided.   The first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion are configured to communicate with one of the supply / discharge passages via an oil passage, and the second main static pressure bearing portion. The pressure bearing portion and the second auxiliary hydrostatic bearing portion are configured to communicate with the other supply / discharge passage among the supply / discharge passages via another oil passage. The variable capacity swash plate type hydraulic rotating machine described.   The first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion are provided in the middle of the oil passage communicating with the one supply / discharge passage. A throttle for independently adjusting the amount of pressure oil supplied to the hydrostatic bearing portion is provided, and the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion communicate with the other supply / discharge passage. An other throttle for adjusting the amount of pressure oil supplied to the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion independently of each other is provided in the middle of the oil passage to be made. 5. A variable capacity swash plate type hydraulic rotating machine according to 5.   Between the first main hydrostatic bearing portion, the first auxiliary hydrostatic bearing portion and the one supply / exhaust passage, one side communicates with the one supply / exhaust passage and the other side communicates with the hydrostatic bearing portion. A common oil passage extending toward the other side, and a branch oil passage branched from each other on the other side of the common oil passage and individually connected to the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion. And between the second main hydrostatic bearing portion, the second auxiliary hydrostatic bearing portion and the other supply / exhaust passage, one side communicates with the other supply / exhaust passage and the other side is the hydrostatic bearing. Other common oil passages that extend toward the portion, and other branches that are branched from each other on the other side of the common oil passage and are individually connected to the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion The variable capacity swash plate type hydraulic rotating machine according to claim 5 or 6, wherein the branch oil passage is provided.   In the middle of the common oil passage, a common throttle is provided for adjusting the amount of pressure oil supplied from the one supply / discharge passage to the first main hydrostatic bearing portion and the first auxiliary hydrostatic bearing portion, In the middle of the other common oil passage, there is another common throttle that adjusts the amount of pressure oil supplied from the other supply / discharge passage to the second main hydrostatic bearing portion and the second auxiliary hydrostatic bearing portion. The variable capacity swash plate type hydraulic rotating machine according to claim 7, wherein the variable capacity swash plate type hydraulic rotating machine is provided.   9. The swash plate according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the swash plate is configured to be tilted and driven in a forward direction and a reverse direction from a neutral position with a tilt angle of zero by the tilt actuator. The variable capacity swash plate type hydraulic rotating machine described. The casing comprises a servo valve having a spool in a control sleeve and controls the tilt control pressure supplied to and discharged from the tilt actuator in accordance with an external command signal, and the tilt operation of the swash plate. A feedback mechanism for following the feedback control of the control sleeve of the regulator,
The feedback mechanism is
When the swash plate is in the neutral position, it becomes an initial position on one side in the axial direction along the rotation axis, and when the swash plate is tilted in the forward and reverse directions, the initial position is directed to the other side in the axial direction. A conversion unit that converts the tilting operation of the swash plate into an axial displacement so as to be displaced,
10. The variable capacitance type according to claim 9, further comprising a displacement transmitting portion that is provided between the conversion portion and the control sleeve of the regulator and transmits an axial displacement taken out by the conversion portion to the control sleeve of the regulator. Swash plate type hydraulic rotating machine.

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