JP5852317B2 - Opposite swash plate type piston pump / motor - Google Patents

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 both sides of the cylinder block. A first swash plate and a second swash plate supported by the housing by two bearing portions, respectively, and reciprocating each cylinder following the first swash plate and the second swash plate as the cylinder block rotates. A first piston and a second piston, a servo mechanism for tilting the first swash plate, and a tilt mechanism for tilting the second swash plate by interlocking the first swash plate and the second swash plate. A rotation interlocking mechanism. Further, the opposed swash plate type piston pump / motor restricts the movement of the second swash plate in the radial direction with respect to the tilt center axis of the second swash plate, and tilts the second swash plate with respect to the housing. The tilting interlock mechanism and the support mechanism are both provided on the same side with respect to the first swash plate and the second swash plate. The 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 both sides of the cylinder block. And a first swash plate and a second swash plate supported by the housing by the second bearing portion, respectively, and each cylinder following the first swash plate and the second swash plate as the cylinder block rotates. The first and second pistons that reciprocate, the servo mechanism that tilts the first swash plate, and the first swash plate and the second swash plate that interlock with each other to tilt the second swash plate. A tilt interlocking mechanism. Further, the opposed swash plate type piston pump / motor restricts the movement of the second swash plate in the radial direction with respect to the tilt center axis of the second swash plate, and tilts the second swash plate with respect to the housing. A support mechanism for supporting the rotation of the second swash plate, the support mechanism including a shaft extending on a tilting central axis of the second swash plate, the shaft comprising the second swash plate and a member attached thereto. At least one and the housing are provided.

In certain embodiments of the present invention, the support mechanism, engages the arcuate rail attached to said housing disposed along the second bearing portion of the circular arc, the rail attached to the second swash plate Engaging member.

  According to the present invention, even if a force is generated to rotate the second swash plate around the motor shaft while the second swash plate is tilted, the second swash plate is lifted from the bearing metal of the bearing portion. Can be prevented.

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. It is a cross-sectional view of a piston motor according to a second embodiment. It is a longitudinal cross-sectional view of the piston motor which concerns on 2nd embodiment. (A) It is a partial cross-sectional view of the alternative example of the piston motor which concerns on 2nd embodiment. (B) It is a fragmentary longitudinal cross-section of the alternative example of the piston motor which concerns on 2nd embodiment.

<First 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 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 second engagement that engages the second swash plate 40 with one end of the swing link 48. A pin 54 and a first engagement pin 53 for engaging the first swash plate 30 with the other end of the swing link 48 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 second swash plate 40 and slidably engages with the recess 55 of the swing link 48 via the slide metal 62.

  The support pins 49, the first engagement pins 53, the second engagement pins 54, and the drive engagement pins 65 have respective center axes orthogonal to the center axis O <b> 5 of the motor shaft 5, and the first and second swash plates 30. , 40 are arranged so as to extend parallel to the tilt center axes O30, 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 side plate 46 is fastened to one side portion of the second swash plate 40 via two bolts 76 and 77. A second engagement pin 54 protrudes from the front end portion of the side plate 46. The second engagement pin 54 is disposed on the first swash plate 30 side with respect to the tilt center axis O40 of the second swash plate 40 via the side plate 46.

  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 second swash plate 40. 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.

  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.

  FIG. 2 shows a state in which the piston motor 1 is switched to the maximum capacity. The tilt angle of the first swash plate 30 becomes a maximum value (for example, 16 to 17 °), and the tilt angle of the second swash plate 40 ( For example, 16 to 17 degrees) is the maximum value. In a state where the piston motor 1 is switched to the minimum capacity, the tilt angle of the first swash plate 30 is 0 °, and the tilt angle TH5 of the second swash plate 40 is a minimum value greater than 0 ° (for example, 6 to 7). °).

  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 cylindrical 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 an arc shape that is a part of a cylinder, and the axis of this 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 cylindrical 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 an arc shape that is 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.

  The shaft 101 is inserted into the hole 25 a of the case 25 and attached to the case 25. The shaft 101 may be fixed to the case 25 or may be rotatably supported. The end of the shaft 101 on the outside of the case is covered with a lid portion 102 having a seal ring 102a, and the housing chamber 24 is sealed with respect to the outside of the case. The lid 102 is screwed to the case 25 and attached.

  The shaft 101 is inserted into the hole (or recess) 46 a of the side plate 46. The central axis of the shaft 101 coincides with the tilt central axis O40 of the second swash plate 40. In the present embodiment, the shaft 101 is not fixed to the side plate 46 so that the side plate 46 can rotate around the shaft 101. On the contrary, when the shaft 101 is fixed to the side plate 46, the shaft 101 is rotatably supported by the case 25 and rotates around the tilt center axis O40. The shaft 101 restricts the movement of the second swash plate 40 in the radial direction with respect to the tilt center axis O40 of the second swash plate 40, and supports the second swash plate 40 so as to be tiltable with respect to the housing (case 25). Configure the support mechanism.

  If possible, the shaft 101 may be inserted into a hole provided in the second swash plate itself instead of the hole of the side plate 46.

  Next, the function and effect of the first embodiment will be described. According to the first embodiment, the opposed swash plate type piston pump motor (piston motor 1) restricts the movement of the second swash plate 40 in the radial direction with respect to the tilt center axis O40 of the second swash plate 40, A support mechanism that supports the swash plate 40 so as to be tiltable with respect to the housing (case 25) is provided. Thereby, it is possible to prevent the second swash plate 40 from floating away from the bearing metal 44 of the second bearing portion 42.

  The support mechanism also includes a shaft 101 that extends on the tilt center axis O40 of the second swash plate 40. The shaft 101 is provided so as to pass through at least one of the second swash plate 40 and a member (side plate 46) attached thereto and the housing (case 25). Therefore, the movement of the second swash plate 40 in the radial direction with respect to the tilt center axis O40 can be reliably restricted while maintaining the tilt of the second swash plate 40 around the tilt center axis O40. It is possible to reliably prevent the plate 40 from floating away from the bearing metal 44 of the second bearing portion 42.

<Second embodiment>
The second embodiment will be described with reference to FIGS. 3 and 4. In the first embodiment, the shaft passing through the case (housing) and the side plate is provided as a support mechanism. However, in 2nd embodiment, the rail attached to the case instead and the engaging member engaged with a rail are provided as a support mechanism. Other configurations are the same as those of the first embodiment, and a description thereof is omitted.

  As shown in FIG. 4, the rail 103 is a member having an arc-shaped cross section, and is disposed in contact with the bearing metal 44 having the arc-shaped cross section of the second bearing portion 42. The center of the arc-shaped surface of the rail 103 and the arc-shaped surface of the bearing metal 44 (that is, the center of the cylinder constituting the arc-shaped surface) coincides with the tilt center axis O40 of the second swash plate 40. The rail 103 has a front surface (arc surface) in conformity with and in contact with the bearing metal 44 on the second swash plate side, and a back surface (arc surface) opposite to the second swash plate side. The rail 103 is attached to the case 25 by screws 107.

  The engaging member 104 is attached to the side surface of the second swash plate 40 in the direction of the tilt center axis O40 of the second swash plate 40 by a bolt 105. The engaging member 104 has an L-shape and has a flat plate portion 104a extending in parallel with the central axis O5 of the motor shaft 5 and a claw extending from the flat plate portion 104a in parallel with the tilted central axis O40 direction. Part 104b. The claw portion 104b is caught by sliding on the back surface of the rail 103 opposite to the second swash plate side, and slides along this back surface.

  5A and 5B, the rail 103 may be omitted by increasing the thickness of the bearing metal 44 of the second bearing portion. Instead, bearing metal 44 is used as the rail. In this case, the claw portion 104b of the engaging member 104 is caught by sliding on the back surface (arc surface) opposite to the second swash plate side of the bearing metal 44, and slides along this back surface. The bearing metal 44 is attached to the case 25 by screws 107.

  The rail 103 and the engaging member 104 restrict the movement of the second swash plate 40 in the radial direction with respect to the tilt center axis O40 of the second swash plate 40, and the second swash plate 40 is moved with respect to the housing (case 25). A support mechanism that supports tilting is configured.

  According to the second embodiment, the support mechanism includes an arcuate rail 103 provided along the arcuate second bearing portion 42 and attached to the housing (case 25), and a rail attached to the second swash plate 40. And an engaging member 104 that engages with 103. Therefore, the movement of the second swash plate 40 in the radial direction with respect to the tilt center axis O40 can be reliably restricted while maintaining the tilt of the second swash plate 40 around the tilt center axis O40. The plate 40 can be reliably prevented from floating away from the bearing metal 44 of the 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 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)
25a hole 30 first swash plate 32 first bearing portion 40 second swash plate 42 second bearing portion 44 bearing metal 46 side plate 46a hole 48 swing link 49 support pin 50 port block (housing)
55 Recessed part 62 Slide metal 101 Shaft 103 Rail 104 Engaging member 104a Flat plate part 104b Claw part O5 Center axis O30 Tilt center axis O40 Tilt center axis

Claims (3)

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 a first bearing portion and a second bearing portion, 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;
An opposed swash plate type piston pump motor having a tilt interlocking mechanism for tilting the second swash plate by interlocking the first swash plate and the second swash plate,
A support mechanism for restricting the movement of the second swash plate in a radial direction with respect to the tilt center axis of the second swash plate and supporting the second swash plate so as to be tiltable with respect to the housing;
Both the tilt interlock mechanism and the support mechanism are provided on the same side with respect to the first swash plate and the second swash plate . 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 a first bearing portion and a second bearing portion, 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;
An opposed swash plate type piston pump motor having a tilt interlocking mechanism for tilting the second swash plate by interlocking the first swash plate and the second swash plate,
A support mechanism for restricting the movement of the second swash plate in a radial direction with respect to the tilt center axis of the second swash plate and supporting the second swash plate so as to be tiltable with respect to the housing;
The support mechanism includes a shaft extending on the tilt center axis of the second swash plate,
The shaft is provided to pass through at least one of the second swash plate and a member attached to the second swash plate and the housing, and is an opposed swash plate type piston pump motor. The support mechanism is
An arcuate rail provided along the arcuate second bearing portion and attached to the housing;
An opposing swash plate type piston pump motor according to claim 1 , further comprising an engaging member attached to the second swash plate and engaged with the rail.

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