JP2005226550A - Hydraulic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial piston pump capable of relatively enlarging an adjusting angle in the peripheral direction of a valve plate while reducing the size. <P>SOLUTION: The adjusting angle in the peripheral direction of the valve plate 7 can be relatively enlarged, while reducing the size, without enlarging the whole more than necessary, by adjusting an angle in the peripheral direction of the valve plate 7 having a suction port 23 for sucking a hydraulic fluid and a delivery port 24 for delivering the hydraulic fluid, by an advance of one angle adjusting mechanism 8 and a retreat of the other angle adjusting mechanism 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fluid pressure device capable of adjusting the angle of a valve plate in the circumferential direction.

  2. Description of the Related Art Conventionally, an axial piston pump / motor as a fluid pressure device of this type contains a rotating shaft and a substantially cylindrical cylinder block that rotates integrally with the rotating shaft in a casing.

  In the cylinder block, a plurality of cylinders in which pistons are accommodated so as to be able to advance and retract are provided in the axial direction of the rotary shaft, and these cylinders are spaced apart from each other in the circumferential direction. In addition, a swash plate is provided at one end of the cylinder block in the axial direction so that the tip of the piston slides in a relatively inclined manner.

  On the other hand, the valve plate is in sliding contact with the other axial end of the cylinder block. The valve plate is provided with a suction port and a discharge port for sucking fluid into the cylinder and discharging fluid from the cylinder as the piston advances and retreats as the cylinder block rotates.

  Further, the valve plate is provided with a notch in the radial direction, and a shaft of a crank-shaped eccentric cam that can be rotated by a pulse motor is fitted into the notch. Then, in order to adjust the suction and discharge timing of the fluid oil, the valve plate is rotated with the eccentric cam by the pulse motor according to the change of the fluid pressure. Is rotated in the circumferential direction (see, for example, Patent Document 1).

Conventionally, an axial piston pump / motor that rotates a valve plate in a circumferential direction by engaging a gear with a gear portion provided on an outer periphery of the valve plate and rotating the gear is also known (for example, (See Patent Document 2).
Japanese Patent Laid-Open No. 10-68378 (page 3-5, FIG. 2-3) Japanese Utility Model Publication No. 6-27835 (Page 2-3, Fig. 1-4)

  However, in the axial piston pump / motor described in Patent Document 1 described above, the valve plate cannot be rotated to a width that is equal to or greater than the diameter of the eccentric cam, so the adjustment angle in the circumferential direction of the valve plate is increased. In order to achieve this, the eccentric cam must be enlarged, and it is not easy to reduce the size, and there is a problem that rattling may occur between the valve plate and the eccentric cam.

  In addition, in the axial piston pump / motor described in Patent Document 2 described above, the gear portion is engaged with the gear portion provided on the valve plate, so that it is not easy to reduce the size as a whole. There is a problem that it is not easy to adjust the valve plate to an accurate rotation angle due to the looseness of the joint.

  The present invention has been made in view of these points, and an object of the present invention is to provide a fluid pressure device capable of relatively increasing the adjustment angle in the circumferential direction of the valve plate while reducing the size. Another object of the present invention is to provide a fluid pressure device that can adjust the valve plate to an accurate rotation angle without rattling.

  The invention according to claim 1 includes a casing, a rotating shaft provided rotatably in the casing, and a plurality of cylinders provided in the axial direction of the rotating shaft, and a cylinder that rotates integrally with the rotating shaft in the casing. A block, a plurality of pistons whose one end is inserted into each cylinder so as to be able to advance and retract, and the other end protrudes from each cylinder, and are provided in a casing so as to be tiltable. A swash plate that reciprocates the cylinder block, a suction port that slides in contact with the swash plate on the opposite side of the cylinder block, and sucks fluid into the cylinder by pulling out the piston from the cylinder as the cylinder block rotates, and a cylinder associated with the rotation of the cylinder block A valve plate with a discharge port that discharges fluid from the cylinder by pushing the piston into the casing, It is a fluid pressure device equipped with a pair of angle adjustment mechanisms that can adjust the angle of the valve plate in the circumferential direction by advancing and retreating the other, and is in sliding contact with the opposite side of the swash plate of the cylinder block to rotate the cylinder block In the circumferential direction of the valve plate equipped with a suction port that sucks fluid into the cylinder by pulling out the piston from the cylinder and a discharge port that discharges fluid from the cylinder by pushing the piston into the cylinder as the cylinder block rotates Adjusting the angle of the valve plate in the circumferential direction while reducing the size without making it unnecessarily large by adjusting the angle by one advancing and retreating the other of the angle adjusting mechanism that is provided in the casing so as to be able to advance and retract. It becomes possible to make the corner relatively large.

  According to a second aspect of the present invention, in the fluid pressure device according to the first aspect, the angle adjusting mechanism protrudes from the casing with respect to the valve plate, and is arranged in parallel with each other so as to face the outer peripheral portion of the valve plate. Since the angle adjusting mechanisms are arranged in parallel with each other so as to face the outer peripheral portion of the valve plate, each angle adjusting mechanism can be operated on the same side, so that the usability is improved.

  According to a third aspect of the present invention, in the fluid pressure device according to the first aspect, the angle adjusting mechanism protrudes from the casing with respect to the valve plate, faces the outer peripheral portion of the valve plate and is opposite to the valve plate. By disposing the angle adjusting mechanism on the opposite side to the valve plate, the valve plate can be securely held from both sides.

  According to a fourth aspect of the present invention, in the fluid pressure device according to any one of the first to third aspects, the angle adjusting mechanism includes an adjusting screw whose tip is in contact with the outer peripheral portion of the valve plate, and an adjusting screw provided on the casing. A screw hole to be screwed and a nut that is screwed to the adjustment screw outside the casing and fixes the adjustment screw to the casing are provided, and the tip end abuts on the outer peripheral portion of the valve plate. The adjustment screw is screwed into a screw hole provided in the casing and is fixed to the casing by a nut outside the casing, so that the valve plate can be rotated with a relatively simple structure and accurate rotation angle in the circumferential direction. It becomes possible to adjust to.

  According to the invention described in claim 1, the circumferential angle of the valve plate provided with the suction port and the discharge port is determined by one advancement and the other retraction of a pair of angle adjustment mechanisms that are provided in the casing so as to be able to advance and retreat. By adjusting, the adjustment angle in the circumferential direction of the valve plate can be made relatively large while downsizing without making the whole unnecessarily large.

  According to the second aspect of the present invention, since the angle adjusting mechanisms are arranged in parallel with each other so as to face the outer peripheral portion of the valve plate, each angle adjusting mechanism can be operated on the same side, so that the usability can be improved.

  According to the third aspect of the invention, the valve plate can be reliably held from both sides by disposing the angle adjusting mechanism on the opposite sides with respect to the valve plate.

  According to the invention of claim 4, by adjusting the adjusting screw whose tip is in contact with the outer peripheral portion of the valve plate to the screw hole provided in the casing and fixing the adjusting screw to the casing with the nut outside the casing, With a relatively simple configuration, the valve plate can be adjusted to an accurate rotation angle in the circumferential direction without rattling.

  Hereinafter, the present invention will be described in detail with reference to the embodiment shown in FIGS.

  FIG. 1 shows an axial piston pump which is a hydraulic device as a fluid pressure device, and this axial piston pump includes a substantially rectangular tubular casing 1, and a rotating shaft 2 is rotatably provided in the casing 1. The rotating shaft 2 is provided with a cylinder block 3 that rotates integrally with the rotating shaft 2 in the casing 1. The cylinder block 3 is provided with a plurality of cylinders 4 in the axial direction of the rotary shaft 2, and pistons 5 are fitted into the cylinders 4 so as to be able to advance and retract. Further, a swash plate 6 that reciprocates each piston 5 with a stroke corresponding to the tilt angle θ is provided in the casing 1 so as to be tiltable. A valve plate 7 is provided on the opposite side of the cylinder block 3 from the swash plate 6, and the casing 1 is provided with a pair of angle adjusting mechanisms 8 and 8 that can adjust the angle of the valve plate 7 in the circumferential direction. ing. Hereinafter, the lower side shown in FIG. 2 that is one end side in the axial direction of the casing 1 will be described as the front side, and the upper side shown in FIG. 2 that is the other end side in the axial direction will be described as the rear side.

  The rotating shaft 2 is inserted into the casing 1 and both end portions protrude from the casing 1, and outer peripheral surfaces on the front end side and the rear end side are rotatably held by bearings 11 and 12, respectively.

  The cylinder block 3 is formed in a substantially cylindrical shape coaxial with the rotary shaft 2, and the rotary shaft 2 is inserted into the through hole 13 in the center and is splined to the rotary shaft 2.

  Each cylinder 4 is provided in a concave shape so as to open to the swash plate 6 side of the cylinder block 3, and is spaced apart from each other at substantially equal intervals in the circumferential direction of the rotating shaft 2. Further, each cylinder 4 is provided with a cylinder port 14 serving as a suction port and a discharge port for hydraulic fluid or the like that is a fluid, penetrating the rear end portion of the cylinder block 3.

  The piston 5 is inserted into each cylinder 4 so that the rear end portion, which is one end portion, can be moved forward and backward, and the front end portion, which is the other end portion, protrudes from each cylinder 4 and is formed into a ball shape. It is held freely. These shoes 15 include a substantially disc-shaped sliding ring 16. The sliding ring 16 is in sliding contact with the sliding surface 17 on the rear side of the swash plate 6 facing the cylinder block 3, and on the sliding surface 17 by the rotation of the cylinder block 3 accompanying the rotation of the rotating shaft 2. Make a circular motion.

  The swash plate 6 is located on the front side of the cylinder block 3, a flat sliding surface 17 is formed on the rear side, and an inclined sliding portion 18 is formed on the front side. The tilt sliding portion 18 is in sliding contact with a concave curved cradle bearing 19 provided in the casing 1 so that the swash plate 6 can tilt with respect to the casing 1.

  The valve plate 7 is in sliding contact with the rear end portion of the cylinder block 3 and is formed in a substantially disc shape as shown in FIG. 2, and is provided coaxially with the rotary shaft 2. Further, the valve plate 7 has a shaft insertion hole 21 formed in the center thereof, and the rotary shaft 2 is inserted through the shaft insertion hole 21. The valve plate 7 has notches 22 and 22 formed in a concave shape on the outer periphery facing the angle adjusting mechanisms 8 and 8, and a suction port 23 around the shaft insertion hole 21. A discharge port 24 is formed in the thickness direction.

  The notches 22 and 22 are provided at positions symmetrical with respect to the center line of the valve plate 7 in plan view.

  The suction port 23 sucks hydraulic oil or the like into the cylinder 4 through the cylinder port 14 by pulling out the piston 5 from the cylinder 4 as the cylinder block 3 rotates, that is, moving forward. The suction port 23 includes, for example, two suction ports 23a and 23b. The suction ports 23a and 23b are formed in a long hole shape that is curved in an arc shape in the circumferential direction of the rotating shaft 2, and the circumferential direction of the rotating shaft 2 Are connected to a suction passage (not shown) that is separated from each other and communicates with the outside of the casing 1. The suction ports 23a and 23b are respectively positioned on one angle adjusting mechanism 8 side with respect to a virtual center line passing between both angle adjusting mechanisms 8 and passing through the center of the valve plate 7.

  The discharge port 24 discharges hydraulic oil or the like from the cylinder 4 through the cylinder port 14 by pushing the piston 5 into the cylinder 4 as the cylinder block 3 rotates, that is, moving backward. The discharge port 24 includes, for example, two discharge ports 24a and 24b. The discharge ports 24a and 24b are formed in a long hole shape that is curved in an arc shape in the circumferential direction of the rotating shaft 2, and the circumferential direction of the rotating shaft 2 Are always connected to a discharge passage (not shown) that is separated from each other and communicates with the outside of the casing 1. The discharge ports 24a and 24b are formed in substantially the same shape as the suction ports 23a and 23b, respectively, and the other angle adjustment is performed with respect to a virtual center line passing between the angle adjustment mechanisms 8 and the center of the valve plate 7. Each is located on the mechanism 8 side. That is, the discharge ports 24 a and 24 b are provided at positions that are point-symmetric with respect to the suction ports 23 a and 23 b with respect to the rotation shaft 2.

  Further, grooves 25 are respectively provided between the suction port 23a and the discharge port 24b and between the suction port 23b and the discharge port 24a toward the other. These groove portions 25 extend in the circumferential direction of the rotary shaft 2 and reduce pressure changes when the cylinder port 14 communicates with the suction ports 23a and 23b and the discharge ports 24a and 24b.

  The angle adjusting mechanisms 8 and 8 are provided so as to be able to advance and retract from the casing 1 with respect to the valve plate 7, and are arranged in parallel to each other so as to face the notches 22 and 22 on the outer peripheral portion of the valve plate 7. These angle adjusting mechanisms 8 and 8 have a so-called double nut structure, and are provided with adjusting screws 31 and 31 as adjusting screws with which the tip end abuts on the outer peripheral portion of the valve plate 7, respectively. The screw holes 32 are respectively screwed into the casing 1. Further, nuts 33, 33 are screwed onto the adjustment screws 31, 31 outside the casing 1.

  Each adjustment screw 31 is formed in an elongated rod shape, and a male screw part 35 is formed on the outer peripheral surface on the base end side, and a body part 36 and a contact part 37 are sequentially formed on the distal end side of the male screw part 35. .

  Each male screw portion 35 is screwed into each screw hole 32 and each nut 33 so that each adjustment screw 31 can be moved back and forth in the opening direction of each screw hole 32 with respect to the casing 1.

  A packing 38 is fitted around each body portion 36 to prevent leakage of hydraulic oil or the like from between each adjustment screw 31 and each screw hole 32. The seal between each adjustment screw 31 and the casing 1 may be a configuration in which the packing 38 is fitted to the casing 1 side, or a configuration in which each male screw portion 35 and each screw hole 32 are sealed with resin or sealant. Is possible.

  Each abutting portion 37 protrudes into the casing 1 in a state in which each adjustment screw 31 is screwed into each screw hole 32, and the tip portion abuts against the abutted portion 39 of each notch portion 22. While being fixed to the circumferential direction of the valve plate 7, the rotation angle of the circumferential direction of the valve plate 7 can be adjusted with the mutual advance / retreat distance with respect to the valve plate 7. Therefore, one of the abutted portions 39, 39 is for turning in one direction of the valve plate 7, and the other is for turning in the other direction opposite to the one direction of the valve plate 7.

  The screw holes 32, 32 are respectively provided in screw base portions 41 provided in the vicinity of the rear end portion of the casing 1, and are provided in parallel to each other in a plan view and at positions corresponding to the notches 22, 22 of the valve plate 7, respectively. It has been. Further, the screw holes 32 are formed only in a portion located inside the screw base portion 41, and the inner side of the casing 1 is a hole portion in which the outer peripheral surface of the body portion 36 of each adjustment screw 31 is in liquid-tight contact. 43.

  Each nut 33 is used to fix each adjustment screw 31 to the casing 1. The nut 33 is screwed into the male screw portion 35 of each adjustment screw 31 outside the casing 1 and fixed to the peripheral portion of each screw base 41. Has been.

  Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described.

  When the rotating shaft 2 is rotated by a motor (not shown) or the like, the cylinder block 3 splined to the rotating shaft 2 rotates integrally with each piston 5, and each piston 5 is guided by a shoe 15 while being guided by a shoe 15. Circular motion on the sliding surface 17 of 6.

  At this time, depending on the tilt angle θ of the swash plate 6, between the maximum push-in position where the piston 5 is pushed most into the cylinder 4 and the maximum pull-out position where the piston 4 is most pulled out for one rotation of the cylinder block 3. Stroke.

  Here, during the half rotation in which the piston 5 strokes from the maximum pushing position to the maximum pulling position, the cylinder port 14 communicates with the suction port 23 and sucks hydraulic oil or the like into the cylinder 4 through the suction passage.

  On the other hand, the cylinder port 14 communicates with the discharge port 24 and discharges the hydraulic oil and the like from the cylinder 4 through the discharge passage during the half rotation of the stroke from the maximum pushing position of the piston 5 to the maximum extraction position. .

  By repeating these operations, the axial piston pump acts as a pump.

  The discharge capacity of the axial piston pump is controlled by changing the stroke of the piston 5 by tilting the swash plate 6 along the cradle bearing 19 and changing the tilt angle θ.

  Further, when adjusting the suction and discharge timing of the axial piston pump, the angle in the circumferential direction of the valve plate 7 is adjusted by the angle adjusting mechanisms 8 and 8, and the suction port 23, the discharge port 24 and the cylinder port 14 are adjusted. Adjust the communication timing.

  Specifically, after the nut 33 of one angle adjustment mechanism 8 is loosened, the adjustment screw 31 is loosened and retracted, and the contact portion 37 is separated from the contacted portion 39 of the notch 22, and then the other angle The nut 33 of the adjustment mechanism 8 is loosened, the adjustment screw 31 is tightened, the contact portion 37 of the adjustment screw 31 is advanced to the inside of the casing 1, and the valve plate 7 is rotated by a predetermined amount by the movement of the contact portion 37. Let

  Thereafter, the nut 33 of the other angle adjusting mechanism 8 is tightened to fix the adjusting screw 31 of the other angle adjusting mechanism 8, and the adjusting screw 31 of the one angle adjusting mechanism 8 is contacted by the abutment portion 37 with the notch 22. Then, the nut 33 is tightened to fix the adjusting screw 31.

  As described above, according to the embodiment shown in FIG. 1 and FIG. 2, the angle in the circumferential direction of the valve plate 7 having the suction port 23 and the discharge port 24 is advanced to the one angle adjusting mechanism 8. And adjusting by moving the other angle adjusting mechanism 8 backward.

  Specifically, the contact portions of the adjusting screws 31 of the angle adjusting mechanisms 8 that are respectively screwed into the screw holes 32 provided in the casing 1 and fixed to the casing 1 by the nuts 33 outside the casing 1. 37 is brought into contact with a contacted portion 39 of a notch 22 provided on the outer peripheral portion of the valve plate 7, and the amount of protrusion of each adjusting screw 31 into the casing 1 is changed to change the circumference of the valve plate 7. It was set as the structure which adjusts the angle of a direction.

  For this reason, the circumferential angle of the valve plate 7 can be delicately set only in accordance with the width dimension of the notches 22 and 22 and the protruding amount of the adjusting screw 31. For example, the valve plate 7 can be set with an eccentric cam or the like. Compared with the conventional structure etc. to rotate, the adjustment angle of the circumferential direction of the valve plate 7 can be made comparatively large, reducing in size, without enlarging the whole axial piston pump more than necessary.

  Further, for example, compared to a conventional case in which a gear meshed with a gear portion provided on the valve plate 7 is rotated to rotate the valve plate 7 in the circumferential direction, rattling due to the gear meshing or the like. Therefore, it is possible to prevent the adjustment accuracy from being lowered, and to adjust the valve plate 7 to an accurate rotation angle in the circumferential direction with a relatively simple configuration.

  As a result, the control characteristics of the axial piston pump can be optimized, the rise of the pressure can be smoothed to prevent overshoot or undershoot, and noise caused by a sudden change in pressure can be reduced.

  Further, by arranging the angle adjusting mechanisms 8 and 8 in parallel with each other, the angle adjusting mechanisms 8 and 8 can be operated on the same side of the casing 1 and the usability can be improved, and the side portion of the casing 1 can be saved in space. Can be

  Then, by fixing the adjustment screw 31 with a double nut structure, the fixed state of the adjustment screw 31 can be held more reliably, and the position of the adjustment screw 31 can be reliably prevented from changing easily.

  Further, by providing the valve plate 7 with the notches 22, 22, the contact portions 37 of the adjustment screws 31 can be surely fitted to the valve plate 7, and the gear protrudes around the valve plate 7. The space inside the casing 1 can be saved as compared with the case where the above is provided.

  In the above-described embodiment, as shown in FIG. 3, the pair of angle adjusting mechanisms 8, 8 are located on the opposite sides of the valve plate 7 and are located away from the center line of the valve plate 7 in plan view. It is also possible to arrange them so that they are positioned substantially on a straight line. In this case, by changing the position of the notch 22 or the screw hole 32 in accordance with the angle adjustment mechanisms 8 and 8, it is possible to achieve the same operational effects as in the above-described embodiment. At the same time, an external force can be applied to the valve plate 7 from opposite directions to hold the valve plate 7 from both sides in a balanced manner.

  Further, the shape or number of the suction port 23 and the discharge port 24 is not limited to the above configuration.

  Furthermore, the angle adjustment mechanisms 8 and 8 can be provided at positions other than the above-described configurations as long as the rotation angle of the valve plate 7 can be adjusted by one advancement and the other retraction.

  And the structure which provides two or more pairs of angle adjustment mechanisms 8 and 8 is also possible.

  In addition, each of the above configurations can be similarly applied to an axial piston motor that is a hydraulic device as a fluid pressure device by reversing suction and discharge to reverse input and output.

It is a cross-sectional top view which shows one Embodiment of the fluid pressure apparatus which concerns on this invention. It is a vertical side view which shows a fluid pressure apparatus same as the above. It is a cross-sectional top view which shows the other Example of a fluid pressure apparatus same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Rotating shaft 3 Cylinder block 4 Cylinder 5 Piston 6 Swash plate 7 Valve plate 8 Angle adjustment mechanism
23 Suction port
24 Discharge port
31 Adjustment screw as adjustment screw
32 Screw hole
33 Nut

Claims (4)

A casing,
A rotating shaft rotatably provided on the casing;
A cylinder block that includes a plurality of cylinders provided in the axial direction of the rotary shaft, and rotates integrally with the rotary shaft within the casing;
A plurality of pistons, one end of which is inserted into each cylinder so as to be able to advance and retreat, and the other end protrudes from each cylinder;
A swash plate provided in the casing so as to be tiltable and reciprocating each piston with a stroke according to the tilt angle;
A suction port that is in sliding contact with the swash plate on the opposite side of the cylinder block and sucks fluid into the cylinder when the piston is pulled out of the cylinder as the cylinder block rotates, and a cylinder that is pressed into the cylinder as the cylinder block rotates A valve plate with a discharge port for discharging fluid from
A fluid pressure device comprising: an angle adjusting mechanism which is provided in a casing so as to be capable of moving forward and backward, and forms a pair capable of adjusting the angle of the valve plate in the circumferential direction by one advancement and the other retreat. The fluid pressure device according to claim 1, wherein the angle adjusting mechanism is provided so as to protrude from the casing with respect to the valve plate, and is arranged in parallel with each other so as to face the outer peripheral portion of the valve plate. 2. The fluid pressure according to claim 1, wherein the angle adjustment mechanism protrudes from the casing with respect to the valve plate, and is disposed on the opposite side of the valve plate while facing the outer peripheral portion of the valve plate. apparatus. The angle adjustment mechanism
An adjustment screw whose tip is in contact with the outer periphery of the valve plate;
A screw hole provided in the casing and screwed with an adjusting screw;
The fluid pressure device according to any one of claims 1 to 3, further comprising a nut that is screwed to the adjustment screw outside the casing and fixes the adjustment screw to the casing.

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