JP2012207556A - Opposed swash plate type piston pump motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a second swash plate from separating from a bearing metal of a bearing part in an opposed swash plate type piston pump motor.SOLUTION: The opposed swash plate type piston pump motor includes: an oscillation link 48 which is swingably supported relative to a housing 25 and is biased from a first swash plate 30 to oscillate on the first swash plate side during rolling of the first swash plate 30; and a driven link 51 swingably supported relative to the housing 25 and driven by the oscillation link 48. The second swash plate 40 includes a journal part 41 stored opposite to the arcuate bearing part 42, and a force for oscillating the second swash plate 40 is applied from the driven link 51 to the journal part 41.

Description

  The present invention relates to a counter-type swash plate type piston pump / motor provided with a tiltable first swash plate and a second swash plate on both sides of a cylinder block.

  The opposed swash plate type piston pump motor disclosed in Patent Document 1 includes a cylinder block in which a plurality of cylinders are open, and a first swash plate and a second swash plate provided on both sides of the cylinder block. The first piston and the second piston of the piston pump motor reciprocate the cylinder following the first and second swash plates as the cylinder block rotates.

  This conventional piston pump motor includes a tilt interlock mechanism that interlocks the first and second swash plates with each other, and a servo mechanism that tilts the first swash plate. For this reason, the tilt angle of the first and second swash plates can be changed using a single servo mechanism.

JP 2009-203927 A

  However, during the tilting of the second swash plate, a force (a force for twisting (twisting) the second swash plate) is generated to rotate the second swash plate about the motor shaft. This is because the point of action of the force that drives the second swash plate is outside the two bearing portions that support the second swash plate. As a result, there arises a problem that the second swash plate biased to the bearing portion by the force of the spring floats away from the bearing metal of the bearing portion for holding the second swash plate.

  In view of the above problems, an object of the present invention is to prevent the second swash plate from floating from the bearing metal of the bearing portion in the opposed swash plate type piston pump motor.

  An opposed swash plate type piston pump / motor according to the present invention includes a cylinder block in which a plurality of cylinders are formed, a housing that houses the cylinder block, and an arc-shaped first bearing provided on both sides of the cylinder block. A first swash plate and a second swash plate supported by the housing by a first portion and a second bearing portion, respectively, and each cylinder following the first swash plate and the second swash plate as the cylinder block rotates. And a servo mechanism for tilting the first swash plate. The opposed swash plate type piston pump motor is supported so as to be swingable with respect to the housing, and is biased from the first swash plate on the first swash plate side while the first swash plate is tilted. And a follower link that is supported so as to be able to swing relative to the housing and that follows the swing link. The second swash plate is provided with a journal portion that is accommodated facing the arc-shaped second bearing portion, and a force that swings the second swash plate acts on the journal portion from the driven link. .

  In one aspect of the present invention, the opposed swash plate type piston pump motor includes a slide metal that is slidably fitted in a recess on the second swash plate side of the driven link, and the journal of the second swash plate The part is connected to the slide metal via a pin.

  According to the present invention, the point of action of the force that swings the second swash plate is close to the second bearing portion, and the second swash plate is rotated around the motor shaft while the second swash plate is tilted. Force is suppressed. As a result, it is possible to prevent the second swash plate from floating from the bearing metal of the second bearing portion.

It is a cross-sectional view of the piston motor according to the first embodiment. It is a longitudinal cross-sectional view of the piston motor which concerns on 1st embodiment.

  1 and 2 show a piston motor 1 according to the first embodiment. The piston motor 1 is used for a hydrostatic transmission (HST) mounted as a transmission on a work vehicle or the like.

  As shown in FIG. 1, the piston motor 1 is an opposed swash plate type piston pump motor, and the piston motor 1 can also be used as a pump. The piston motor 1 includes a first swash plate 30 and a second swash plate 40 on both sides of the cylinder block 4. The basic structure of the piston motor 1 is the same as that of the conventional piston motor disclosed in Japanese Patent Laid-Open No. 2009-203927.

  In the piston motor 1, a housing chamber 24 is formed by a case 25 and a port block 50, and the cylinder block 4 and the first and second swash plates 30 and 40 are accommodated in the housing chamber 24. The case 25 and the port block 50 may be collectively referred to as a housing (accommodating member).

  The motor shaft 5 passes through the cylinder block 4 and is attached thereto. The motor shaft 5 is rotatably supported by the port block 50 via a bearing 91 and is rotatably supported by the case 25 via a bearing 92.

  A plurality of cylinders 6 are formed in the cylinder block 4 at a constant interval on the same circumference around the axis. A first piston 8 and a second piston 9 are inserted into the cylinder 6 from both sides, and a volume chamber 10 is formed between them.

  One ends of the first and second pistons 8 and 9 protrude from both end surfaces of the cylinder block 4, and are supported by the first and second swash plates 30 and 40 via shoes 21 and 22. When the cylinder block 4 rotates, the first and second pistons 8 and 9 reciprocate in opposite directions between the first and second swash plates 30 and 40.

  As shown in FIG. 1, the oil passages for supplying and discharging the hydraulic oil to and from the respective volume chambers 10 include a pair of bearing ports 39 that open to the first bearing portion 32 (first sliding bearing portion) of the port block 50, and the first oblique ports. A pair of swash plate ports 16 opened in the plate 30, the same number of valve ports 61 as the cylinders 6 opened in the swash plate plate 60, and the shoe ports 19 penetrating each shoe 21 are formed.

  The flow of hydraulic oil in the piston motor 1 is as follows: one bearing port 39 → one swash plate port 16 → valve port 61 → shoe port 19 → volume chamber 10 → shoe port 19 → valve port 61 → the other swash plate port 16 → The other bearing port 39 is provided. The first and second pistons 8 and 9 reciprocate the cylinder 6 in directions opposite to each other by the hydraulic pressure guided to each volume chamber 10, and the cylinder block 4 and the motor shaft 5 rotate.

  A plurality of springs 95 and 96 are provided as means for biasing the shoes 21 and 22. Springs 95 and 96 are placed in the holes 93 and 94 of the cylinder block 4, respectively. The urging force of each spring 95 is transmitted to each shoe 21 via the retainer holder 97 and the retainer plate 98, and each shoe 21 is pressed against the swash plate 60 by this urging force. The urging force of each other spring 96 is transmitted to each shoe 22 via the retainer holder 87 and the retainer plate 88, and each shoe 22 is pressed against the second swash plate 40 by this urging force. As a result, the swash plate 40 is biased to the second bearing portion 42 described later by the spring force (elastic force) of the spring 96.

  The first and second swash plates 30 and 40 are supported by the first bearing portion 32 and the second bearing portion 42 so as to be tiltable via the swash plate rear journal portions 31 and 41, respectively, and perform one rotation of the piston motor 1. The displacement volume per hit can be changed. The ratio of the rotational speeds of the input-side pump shaft and the output-side motor shaft 5 changes according to the ratio of the displacement volume of the piston pump and the piston motor 1. The swash plate rear journal portions 31 and 41 are portions that are accommodated to face the first bearing portion 32 and the second bearing portion 42, respectively.

  The servo mechanism 33 is provided in the port block 50 of the piston motor 1 and tilts the first swash plate 30. The servo mechanism 33 includes a servo regulator piston 34 slidably received in the port block 50. When the servo regulator piston 34 is moved by hydraulic pressure or the like, the first swash plate 30 is tilted via the driving engagement pin 65 and the slide metal 66. The servo regulator piston 34 is formed with an annular recess 67 for slidably engaging the slide metal 66, and the driving engagement pin 65 is engaged with the recess 67 via the slide metal 66. The movement of the servo regulator piston 34 is transmitted to the first swash plate 30 via the slide metal 66 and the driving engagement pin 65.

  The piston motor 1 is provided with a tilt interlock mechanism 45 that interlocks the first and second swash plates 30 and 40 with each other. The tilt interlock mechanism 45 includes a swing link 48 that is swingably connected to the case 25 via a support pin 49, and a driven link 51 that is swingably connected to the case 25 via a support pin 52. . Furthermore, the tilt interlock mechanism 45 engages the first engagement pin 53 for engaging the first swash plate 30 with one end of the swing link 48 and the one end of the driven link 51 with the other end of the swing link 48. A second engagement pin 54 and a third engagement pin 56 for engaging the second swash plate 40 with the other end of the driven link 51 are provided. As will be described later, the dimensions of the respective parts are set so that the tilt angles of the first and second swash plates 30 and 40 change with a predetermined relationship.

  The first engagement pin 53 protrudes from the side portion of the first swash plate 30 and slidably engages with the recess 58 of the swing link 48 via the slide metal 75. The second engagement pin 54 protrudes from the side portion of the driven link 51 and slidably engages with the concave portion 55 of the swing link 48 via the slide metal 62. The third engagement pin 56 protrudes from the side portion of the second swash plate 40 and slidably engages with the recess 57 of the driven link 51 via the slide metal 64.

  The support pins 49, the support pins 52, the first engagement pins 53, the second engagement pins 54, the third engagement pins 56, and the drive engagement pins 65 are center axes O 5 of the motor shaft 5. The first and second swash plates 30 and 40 are arranged so as to extend in parallel with the tilting central axes O30 and O40.

  As shown in FIG. 1, the servo mechanism 33 and the tilt interlock mechanism 45 are arranged so that the first swash plate 30 is sandwiched between them. The driving engagement pin 65 and the first engagement pin 53 protrude from opposite sides of the first swash plate 30 in opposite directions.

  A second engagement pin 54 protrudes from the distal end portion of the driven link 51. The second engagement pin 54 is disposed closer to the first swash plate 30 than the tilt center axis O 40 of the second swash plate 40.

  The swing link 48 is supported by the support pin 49 via a bearing 63 so as to be swingable. The support pin 49 is fastened to the bracket 82 via a nut 83. The bracket 82 is fastened to the case 25 via a plurality of screws 84.

  The swing link 48 includes a first link portion 48 a extending from the support pin 49 toward the first swash plate 30, and a second link portion 48 b extending from the support pin 49 toward the driven link 51. A recess 58 that engages the slide metal 75 is formed in the first link portion 48a, and a recess 55 that engages the slide metal 62 is formed in the second link portion 48b. The slide metal 62 can slide in the recess 55 of the swing link 48 and can swing (rotate) with respect to the second engagement pin 54. The slide metal 75 can slide in the recess 58 of the swing link 48 and can swing (rotate) with respect to the first engagement pin 53.

  The driven link 51 includes a third link portion 51a extending from the support pin 52 toward the swing link 48, and a fourth link portion 51b extending from the support pin 52 toward the swash plate rear surface journal portion 41 of the second swash plate 40. Have A second engagement pin 54 that engages the slide metal 62 is formed on the third link portion 51a, and a recess 57 that engages the slide metal 64 is formed on the fourth link portion 51b. The slide metal 62 can slide in the recess 55 of the swing link 48 and can swing (rotate) with respect to the second engagement pin 54. The slide metal 64 can slide in the concave portion 57 of the driven link 51 and can swing (rotate) with respect to the third engagement pin 56.

  As the servo regulator piston 34 of the servo mechanism 33 moves, the first swash plate 30 tilts, and the second swash plate 40 tilts in conjunction with the first swash plate 30 via the tilt interlock mechanism 45. To do. The capacity of the piston motor 1 is continuously changed according to the stroke of the servo regulator piston 34.

  The first swash plate 30 rotates about the tilt center axis O30 via the swash plate backside journal portion 31. The pair of swash plate rear journal portions 31 protrudes from the back of the first swash plate 30 in a half-log shape, and the arc-shaped sliding surface slides through the bearing metal 38 of the first bearing portion 32 of the port block 50. It is supported movably. The first bearing portion 32 and the bearing metal 38 having an arcuate cross section have a shape of a part of a cylinder, and the axis of the cylinder coincides with the tilt center axis O30. The swash plate rear journal portion 31 is formed integrally with the first swash plate 30, but is not limited thereto and may be formed separately from the first swash plate 30.

  The driving engagement pin 65 and the first engagement pin 53 are fixed by being press-fitted into each hole formed in the swash plate back surface journal portion 31. Accordingly, the driving engagement pin 65 and the first engagement pin 53 are provided so as to protrude from the side surface of the swash plate rear surface journal portion 31.

  The second swash plate 40 rotates around the tilt center axis O40. The pair of swash plate rear surface journal portions 41 protrudes from the back of the second swash plate 40 in a half-log shape, and the arc-shaped sliding surface thereof is a bearing of the second bearing portion 42 (second sliding bearing portion) of the case 25. The metal 44 is slidably supported. The second bearing portion 42 and the bearing metal 44 having an arcuate cross section have a shape of a part of a cylinder, and the axis of this cylinder coincides with the tilt center axis O40. The swash plate rear journal 41 is formed separately from the second swash plate 40 and is fixed to the second swash plate 40 via two knock pins. However, the present invention is not limited to this, and the swash plate rear surface journal 41 may be formed integrally with the second swash plate 40.

  Hereinafter, the point which improved the piston motor 1 from the conventional piston motor is described.

  As described above, the driven link 51 is rotatably supported with respect to the case 25 via the support pin 52, and swings via the second engagement pin 54 and the slide metal 62 by swinging of the swing link 48. The link 48 swings in the direction opposite to the swing direction. A third engagement pin 56 that connects the swash plate back journal 41 of the second swash plate 40 and the driven link 51 is connected to the swash plate back journal portion 41 of the second swash plate 40. For this reason, the position of the third engagement pin 56, which is the point of application of the force from the driven link 51 of the tilt interlock mechanism 45 to the second swash plate 40, is close to the second bearing portion 42.

  That is, the tilting interlocking mechanism 45 of the present embodiment is configured so that the second swash plate 40 can be tilted from the driven link 51 while appropriately maintaining the tilting angle range of the second swash plate 40 via the driven link 51 driven by the swing link 48. The point of action of the force acting on the swash plate 40 (swinging force) is brought closer to the second bearing portion 42. As a result, a force acting on the second swash plate 40 is received by the second bearing portion 42, and a force for rotating the second swash plate 40 about the motor shaft 5 during the tilting of the second swash plate ( That is, the force that twists (twists) the second swash plate is reduced.

  Next, the function and effect of this embodiment will be described. According to the present embodiment, the swing link 48 is supported so as to be swingable with respect to the housing 25, and is biased from the first swash plate 30 on the first swash plate side while the first swash plate 30 is tilted. Rocks. The driven link 51 is supported so as to be swingable with respect to the housing 25, and is driven by the swing link 48. The second swash plate 40 is provided with a journal portion 41 that is accommodated to face the arc-shaped second bearing portion 42. A force that swings the second swash plate 40 acts on the journal portion 41 from the driven link 51.

  As a result, the point of application of the force from the driven link 51 to the second swash plate 40 approaches the second bearing portion 42, and the force to rotate the second swash plate 40 about the motor shaft 5 is suppressed. The As a result, the swash plate backside journal 41 of the second swash plate 40 can be prevented from floating with respect to the bearing metal 44 of the second bearing portion 42.

  As an example, the slide metal 64 is slidably fitted into the recess 57 on the second swash plate side of the driven link 51, and the journal portion 41 of the second swash plate 40 is connected to the slide metal 64 via the pin 56. . As a result, the swash plate back surface journal 41 of the second swash plate 40 can be more reliably prevented from floating with respect to the bearing metal 44 of the second bearing portion 42.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea. For example, the first engagement pin 53, the second engagement pin 54, and the third engagement pin 56 are provided in the swash plate back journal portion 31, the driven link 51, and the swash plate back journal portion 41, respectively. The metal 75, the slide metal 62, and the slide metal 64 can also be provided. In this case, holes that fit into the first engagement pin 53, the second engagement pin 54, and the third engagement pin 56 are formed in the swash plate rear journal portion 31, the driven link 51, and the swash plate rear journal portion 41, respectively. Provided. Further, for example, the piston motor 1 can be used as a hydraulic pump as a swash plate type hydraulic piston pump / motor.

1 Piston motor (piston pump / motor)
4 Cylinder block 5 Motor shaft 6 Cylinder 8 First piston 9 Second piston 10 Volume chamber 25 Case (housing)
30 First Swash Plate 32 First Bearing 40 Second Swash Plate 42 Second Bearing 48 Swing Link 49 Support Pin 50 Port Block (Housing)
51 Follower Link 52 Support Pin 53 First Engagement Pin 54 Second Engagement Pin 55 Recess 56 Third Engagement Pin 62 Slide Metal 64 Slide Metal O5 Center Axis O30 Tilt Center Axis O40 Tilt Center Axis

Claims (2)

A cylinder block formed with a plurality of cylinders;
A housing that houses the cylinder block;
A first swash plate and a second swash plate provided on both sides of the cylinder block and supported by the housing by arc-shaped first bearing portions and second bearing portions, respectively;
A first piston and a second piston that reciprocate each cylinder following the first swash plate and the second swash plate with the rotation of the cylinder block;
A servo mechanism for tilting the first swash plate, and an opposed swash plate type piston pump motor,
A swing link that is swingably supported with respect to the housing and swings by being biased from the first swash plate on the first swash plate side during tilting of the first swash plate;
A follower link supported so as to be swingable with respect to the housing and following the swing link;
The second swash plate is provided with a journal portion that is accommodated facing the arc-shaped second bearing portion,
2. A counter-type swash plate type piston pump motor, wherein a force for swinging the second swash plate acts on the journal portion from the driven link. The opposed swash plate type piston pump motor includes a slide metal that slidably fits in a recess on the second swash plate side of the driven link,
2. The opposed swash plate type piston pump motor according to claim 1, wherein the journal portion of the second swash plate is connected to the slide metal through a pin.

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