JPH0643271U - Swash plate type fluid pump / motor - Google Patents

Abstract

(57) [Abstract] [Purpose] The inclination angle G of the thick portion 53 of the swash plate 51 is increased to increase the fluctuation range of the rotation speed of the cylinder block 38 and the rotation shaft 28. [Composition] Center of curvature C of spherical portion 77 of thrust ball 74
Is located on the axis L of the rotary shaft 28 on the other side of the intersection point K, the thrust ball 74 is separated from the swash plate 51, and a certain amount of extra space is formed between the thrust ball 74 and the swash plate 51. The inclination angle G of the flesh portion 53 can be increased while preventing interference between the spherical surface portion 77 and the inner peripheral end of the swash plate 51. This allows
The difference in stroke of the plunger 40 when the swash plate 51 is at different tilting positions is large.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a swash plate type fluid pump / motor in which a stroke of a plunger is changed by tilting a swash plate.

[0002]

[Prior art]

 As a conventional swash plate type fluid motor, for example, the one described in Japanese Patent Publication No. 4-42550 is known. This is formed on the casing, a rotating shaft rotatably supported by the casing, a cylinder block that is housed in the casing and connected to the rotating shaft so that it can rotate as a unit, and on one end surface of the cylinder block. A slidable slant plate disposed between one end surface of the cylinder block and one end inner surface of the casing; A tilting means for tilting the swash plate between two tilting positions, and a plurality of slidable plates slidably contacting an inclined surface located at the other end of the swash plate and connected to one end of the plunger through a ball joint joint, respectively. And a ring-shaped retainer plate that is loosely fitted to the outside of the rotating shaft and that engages with the shoe, and a spherical surface that is fitted to the outside of the rotating shaft and projects in a convex shape toward one side. Part of And a thrust ball having a spherical portion on the outer circumference that makes spherical contact with the inner circumference of the circular retainer plate, and the center of curvature of the spherical portion of the thrust ball is the plane connecting the spherical centers of the ball joint joint and the axis of the rotary shaft. It is located on the intersection with.

[0003]

[Problems to be solved by the device]

 However, in such a conventional swash plate type fluid motor, as described above, the center of curvature C of the spherical portion 12 of the thrust ball 11 is set to the plane H connecting the center S of the ball 15 of the ball joint joint 14. Since it is located on the intersection K with the axis L of the rotary shaft 13 (see FIG. 3), the thrust ball 11 is arranged close to the swash plate 16, and as a result, the spherical portion of the thrust ball 11 is located. There is a possibility that 12 and the inner peripheral end of the swash plate 16 near the thrust ball 11 may interfere with each other. Here, in order to prevent such interference, the tilt angle T of the swash plate 16 and the minimum thickness N of the thin portion of the swash plate 16 cannot be changed. There is no choice but to reduce the inclination angle G in the thick portion. As a result, the difference between the stroke of the plunger 17 when the swash plate 16 is in one tilt position and the stroke of the plunger 17 when the swash plate 16 is in the other tilt position is small, and the cylinder block 18 However, there is a problem that the fluctuation range of the rotation speed of the rotating shaft 13 becomes narrow.

An object of the present invention is to provide a swash plate type fluid pump / motor capable of increasing the fluctuation range of the rotation speed of the cylinder block and the rotation shaft.

[0005]

[Means for Solving the Problems]

 The purpose is to provide a casing, a rotary shaft that is rotatably supported by the casing, a cylinder block that is housed in the casing and that is connected to the rotary shaft so as to rotate integrally, and one end surface of the cylinder block. A plunger slidably inserted into each of the plurality of axially extending cylinder holes; a tiltable swash plate disposed between one end surface of the cylinder block and one end inner surface of the casing; A tilting means for tilting the plate, a plurality of shoes slidably contacting an inclined surface located at the other end of the swash plate and respectively connected to one end of the plunger through a ball joint joint, and an outer side of the rotary shaft. A retainer plate that is loosely fitted and that engages with the shoe, and a part of a spherical surface that is fitted to the outside of the rotating shaft and that projects in a convex shape toward one side. And a thrust ball having a spherical surface on the outer circumference that makes spherical contact with the inner circumference of the plate, and the stroke of the plunger is changed by tilting the swash plate by the tilting means. -In the motor, it is achieved by locating the center of curvature of the spherical portion of the thrust ball on the axis of the rotating shaft on the other side from the intersection of the plane connecting the spherical centers of the ball joint joint and the axis of the rotating shaft. You can

[0006]

[Action]

 In this invention, as shown in FIG. 2, the center of curvature C of the spherical portion 12 of the thrust ball 11 is defined by the plane H connecting the centers S of the balls 15 of the ball joint joint 14 and the axis L of the rotary shaft 13. Since the thrust ball 11 is positioned on the axis L of the rotary shaft 13 on the other side of the intersection K, for example, at a predetermined distance M 1 from the intersection K, the thrust ball 11 is separated from the swash plate 16 and between the thrust ball 11 and the swash plate 16. A certain amount of extra space is created, and as a result, the swash plate 16 is tilted under the condition that the tilt angle T, the minimum wall thickness N of the thin wall portion of the swash plate 16 and the radius of curvature R of the spherical portion 12 are constant. The inclination angle G of the thick portion 16 can be increased while preventing interference between the spherical portion 12 of the thrust ball 11 and the inner peripheral end of the swash plate 16. As a result, the stroke difference of the plunger 17 when the swash plate 16 is at different tilting positions becomes large, and as a result, the fluctuation range of the rotation speed of the cylinder block 18 and the rotating shaft 13 becomes large.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 21 denotes, for example, a swash plate type fluid motor for driving a crawler vehicle. The fluid motor 21 has a case body 22, and the other end surface of the case body 22 has a cylindrical storage chamber extending toward one side. 23 are formed. A side plate 24 is fixed to the other end of the case main body 22, so that the storage chamber 23 is closed and sealed by the side plate 24. Reference numeral 28 denotes a rotary shaft having the other side portion inserted into the storage chamber 23, and the rotary shaft 28 is rotatably supported by the side plate 24 and the case body 22 via a pair of bearings 29, 30. One end of the rotary shaft 28 projects from the case body 22 and is connected to a sprocket that engages with a crawler (not shown). The case body 22 and the side plate 24 described above constitute the casing 33 of the fluid motor 21 as a whole.

Reference numeral 38 denotes a cylindrical cylinder block housed in the housing chamber 23, and the other end of the rotary shaft 28 is inserted into the cylinder block 38 and spline-coupled so that the cylinder block 38 and the rotary shaft 28 are connected so as to rotate together. A plurality of cylinder holes 39 extending in the axial direction are formed on one end surface of the cylinder block 38, and these cylinder holes 39 are arranged equidistantly in the circumferential direction. Plural plungers 40 of the same number as the cylinder holes 39 are slidably inserted in the cylinder holes 39, and a spherical ball portion 41 is formed at the tip, that is, one end of each plunger 40. Reference numeral 42 denotes a timing plate fixed to the side plate 24 and located between the cylinder block 38 and the side plate 24. The timing plate 42 is formed with two long arc-shaped holes 43 spaced apart in the circumferential direction. The cylinder holes 39 are successively connected to each other by the rotation of the cylinder block 38. 44 and 45 are supply / discharge passages formed in the side plate 24. The supply / discharge passage 44 is always in communication with one arc-shaped hole 43, and the supply / discharge passage 45 is always in communication with the other arc-shaped hole 43. Further, these supply / discharge passages 44, 45 are connected to a pump and a tank via a switching valve (not shown), and when the switching valve is switched, one of them becomes a supply side and the other becomes a discharge side.

Reference numeral 51 denotes a substantially ring-shaped swash plate disposed between one end surface of the cylinder block 38 and one end inner surface (bottom surface of the storage chamber 23) 32 of the casing 33. 28 penetrates. An inclined surface (the other end surface) 52 of the swash plate 51 facing the cylinder block 38 is inclined with respect to a plane perpendicular to the axis L of the rotary shaft 28, and as a result, the swash plate 51 has a thick portion 53 with the central portion as a boundary. And a thin portion 54. Further, the back surface (one end surface opposite to the inclined surface 52) 55 of the swash plate 51 facing the inner surface 32 at the one end is located on the thick portion 53 side substantially parallel to the vertical surface with respect to the axis L of the rotating shaft 28. The first flat surface 56 and the second flat surface 57 which is inclined with respect to the first flat surface 56 at a predetermined small tilt angle T and is located on the thin portion 54 side are composed of two flat surfaces. The boundary between the first and second flat surfaces 56 and 57 is separated from the center of the swash plate 51 toward the thick portion 53 by a predetermined distance.

Reference numeral 58 denotes two spherical fulcrum members, and a straight line (tilt straight line) connecting the sphere centers of these fulcrum members 58 becomes a tilt center line of the swash plate 51. Here, each of the fulcrum members 58 has two hemispherical recesses 63 formed in the back surface 55 on the boundary between the first and second flat surfaces 56 and 57, half of which is opposed to the recesses 63. The two halves are inserted into two hemispherical recesses 64 formed on the inner surface 32 at one end while making spherical contact. As a result, in the swash plate 51, the second flat surface 57 and the one inner surface 32 are in surface contact with each other with the straight line (the tilted straight line) connecting the spherical centers of these two fulcrum members 58 as the center. It is possible to tilt between the tilted position and the second tilted position where the first flat surface 56 and the one end inner surface 32 are in surface contact with each other.

70 is the same number of shoes as the plungers 40, and each shoe 70 is formed with a ball hole 71 in which the ball portion 41 of the plunger 40 is accommodated. The ball portion 41 and the ball hole 71 described above together constitute a ball joint joint 72, whereby one end of the plunger 40 and the shoe 70 are connected via the ball joint joint 72. The shoes 70 are slidably engaged with the inclined surface 52 of the swash plate 51. A retainer plate 73 is a ring-shaped retainer plate loosely fitted to the outside of the rotary shaft 28, and the retainer plate 73 is arranged between the cylinder block 38 and the swash plate 51. Further, the retainer plate 73 is engaged with all the shoes 70, and the inner circumference 76 thereof is composed of a part of a spherical surface gradually expanding toward the other. A thrust ball 74 is arranged between the cylinder block 38 and the retainer plate 73.The thrust ball 74 has a spherical surface portion 77 which is a part of a spherical surface protruding in one direction on the outer circumference. The spherical portion 77 is in spherical contact with the inner circumference 76 of the retainer plate 73. The thrust ball 74 is fitted to the outside of the rotating shaft 28 and is connected to the rotating shaft 28 by spline connection. 75 is a spring as an urging member interposed between the cylinder block 38 and the thrust ball 74.This spring 75 urges the thrust ball 74 and the retainer plate 73 toward the swash plate 51, Press the shoe 70 against the inclined surface 52 of the swash plate 51. The center of curvature C of the spherical surface portion 77 of the thrust ball 74 is the intersection point K of the spherical center S of the ball joint joint 72, that is, the plane H connecting the centers of curvature of the spherical portion 41 and the axis L of the rotary shaft 28. It is located on the axis L of the rotating shaft 28 on the other side.

A cylinder chamber 80 is formed inside the casing 33 facing the second flat surface 57 of the swash plate 51, and a pressing piston 82 is inserted into the cylinder chamber 80 so as to be movable in the axial direction of the rotary shaft 28. Has been done. Reference numeral 84 denotes a fluid passage formed in the casing 33. One end of the fluid passage 84 is connected to a fluid source (not shown) and the other end is connected to the cylinder chamber 80. When the high-pressure fluid is supplied to the cylinder chamber 80 through the fluid passage 84, the pressing piston 82 moves toward the swash plate 51 while being in contact with the thin-side rear surface 55 of the swash plate 51. 51 tilts from the first tilt position to the second tilt position about the tilt line, and when the supply of high-pressure fluid to the cylinder chamber 80 stops, the tilt line moves from the center of the swash plate 51. Since it is offset to the thick portion 53 side, the swash plate 51 is tilted from the second tilt position to the first tilt position by the pressing force from the plunger 40. As a result, the stroke of the plunger 40 in the cylinder block 38 is changed in two steps, and the rotational speeds of the cylinder block 38 and the rotary shaft 28 are changed in two steps. The cylinder chamber 80, the pressing piston 82, and the fluid passage 84 described above collectively constitute the tilting means 85 for tilting the swash plate 51 between the two tilting positions as described above.

Next, the operation of the embodiment of the present invention will be described. When high-pressure fluid is supplied from the supply / discharge passage 44 through one arc-shaped hole 43 to the cylinder hole 39 of the cylinder block 38, the plunger 40 in the cylinder hole 39 projects toward the swash plate 51 and presses the inclined surface 52. However, at this time, since the tip end of the plunger 40 is engaged with the inclined surface 52 via the shoe 70, the component force of the pressing force acts on the plunger 40, whereby the plunger 40 and the shoe 70 are inclined. Sliding on the surface 52 from the thick portion 53 side toward the thin portion 54 side, the plunger 40, the cylinder block 38, and the rotary shaft 28 rotate integrally. Due to the rotation of the cylinder block 38, the plunger 40 in the cylinder hole 39 communicating with the other arcuate hole 43 is engaged with the inclined surface 52 of the swash plate 51 via the shoe 70 and is thickened from the thin portion 54 side. Since it moves toward the meat portion 53 side, it is gradually pushed into the cylinder hole 39 by the inclined surface 52, and the fluid in the cylinder hole 39 is pushed out and discharged through the other arc-shaped hole 43 and the supply / discharge passage 45. . At this time, the shoe 70 is pressed against the inclined surface 52 of the swash plate 51 by the urging force of the spring 75 transmitted through the thrust ball 74 and the retainer plate 73, so that the shoe 70 is separated from the plunger 40 by the centrifugal force. Also, when the fluid motor 21 acts as a pump and the plunger 40 draws in fluid, the shoe 70 is prevented from rising from the inclined surface 52 of the swash plate 51.

Here, for example, when the crawler vehicle is climbing a slope, the fluid motor 21 must rotate at a low speed with a large torque. In this case, the supply of the high pressure fluid to the cylinder chamber 80 through the fluid passage 84 is stopped, and the swash plate 51 is not pressed by the pressing piston 82. Here, as described above, since the tilting straight line is offset from the center of the swash plate 51 to the thick portion 53 side, the swash plate 51 is pressed against the second flat surface 57 and the inner surface at one end by the pressing force from the plunger 40. It is tilted to the first tilted position where it comes into surface contact with 32. At this time, the stroke of the plunger 40 in the cylinder block 38 becomes long, but the amount of high-pressure fluid flowing into the fluid motor 21 is constant, so the rotation speed of the cylinder block 38 and the rotation shaft 28 becomes low.

Next, when the crawler vehicle starts to run steadily on level ground, for example, the fluid motor 21 must be rotated at a high speed with a small torque. In this case, high-pressure fluid is supplied to the cylinder chamber 80 through the fluid passage 84, and the pressing piston 82 is moved toward the swash plate 51 while being in contact with the back surface 55 of the thin portion 54 of the swash plate 51. As a result, the swash plate 51 is pushed by the pressing piston 82 and tilts about the tilting straight line from the first tilting position to the second tilting position where the first flat surface 56 and one end inner surface 32 make surface contact. . As a result, the stroke of the plunger 40 in the cylinder block 38 is shortened, and the cylinder block 38 and the rotary shaft 28 rotate at high speed.

Here, if the center of curvature C of the spherical surface portion 77 of the thrust ball 74 is located on the axis L of the rotary shaft 28 on the other side of the intersection K as described above, the thrust ball 74 is separated from the swash plate 51. A certain amount of extra space is formed between the swash plate 51 and the swash plate 51. As a result, the tilt angle T of the swash plate 51, the minimum thickness N of the thin wall portion 54 of the swash plate 51, and the radius of curvature R of the spherical surface portion 77 are constant. Under the condition that, the inclination angle G in the thick portion 53 of the swash plate 51, that is, the intersection angle between the inclined surface 52 and the first flat surface 56, is defined by the spherical portion 77 of the thrust ball 74 and the inner circumference of the swash plate 51. It can be enlarged while preventing interference with the edges. This increases the stroke difference of the plunger 40 when the swash plate 51 is in different tilted positions, that is, the first tilted position and the second tilted position, and the cylinder block 38 and the rotary shaft 28 are tilted at these tilted positions. The fluctuation range of the rotation speed of is large.

In the above-described embodiment, the back surface 55 of the swash plate 51 is composed of two flat surfaces 56 and 57 intersecting each other at a predetermined tilt angle T, and one end of the casing 33 facing the back surface 55. Although the inner surface 32 is composed of one flat surface, in the present invention, the back surface 55 of the swash plate 51 is composed of one flat surface, and two inner surfaces of the casing 33 at one end intersect at a predetermined tilt angle T. You may make it comprised from a flat surface. Further, in the above-mentioned embodiment, the back surface 55 of the swash plate 51 is composed of two flat surfaces 56 and 57, but in the present invention, the back surface 55 of the swash plate 51 is composed of three flat surfaces. The 51 may be tilted between three tilting positions. Further, although the invention is applied to the fluid motor 21 in the above-described embodiment, the invention may be applied to the fluid pump.

[0018]

[Effect of device]

 As described above, according to this invention, the fluctuation range of the rotation speeds of the cylinder block and the rotary shaft can be increased.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the principle of this invention.

FIG. 3 is an explanatory view similar to FIG. 2, showing a conventional swash plate type fluid motor.

[Explanation of symbols]

 21 ... Swash plate type fluid motor 28 ... Rotating shaft 32 ... One end inner surface 33 ... Casing 38 ... Cylinder block 39 ... Cylinder hole 40 ... Plunger 51 ... Swash plate 52 ... Inclined surface 70 ... Shoe 72 ... Ball joint joint 73 ... Retainer plate 74 ... Thrust ball 76 ... Inner circumference 77 ... Spherical part 85 ... Tilting means C ... Center of curvature S ... Center of sphere H ... Plane L ... Axis line K ... Intersection point

Claims (1)

[Scope of utility model registration request] 1. A casing 33, a rotary shaft 28 rotatably supported by the casing, a cylinder block 38 housed in the casing and connected to the rotary shaft so as to be integrally rotatable, and one end surface of the cylinder block. Plunger 40 slidably inserted in each of a plurality of axially extending cylinder holes 39 formed in the cylinder, and a tiltable swash plate disposed between one end surface of the cylinder block and one end inner surface 32 of the casing. 51, a tilting means 85 for tilting the swash plate, and a plurality of shoes slidably contacting the inclined surface 52 located at the other end of the swash plate and connected to one end of the plunger through a ball joint joint 72, respectively. 70, a substantially ring-shaped retainer plate 73 that is loosely fitted to the outside of the rotation shaft and that engages with the shoe,
A thrust ball 74 fitted on the outside of the rotary shaft and having a spherical surface portion 77 on the outer circumference, which is formed of a part of a spherical surface protruding in a convex shape toward one side and is in spherical contact with the inner circumference 76 of the retainer plate,
In the swash plate type fluid pump / motor 21 in which the stroke of the plunger is changed by tilting the swash plate by the tilting means, the center of curvature C of the spherical portion of the thrust ball is set to the ball joint. A swash plate type fluid pump / motor, characterized in that it is positioned on the axis of the rotary shaft on the other side from the intersection K of the plane H connecting the spherical centers S of the joint and the axis L of the rotary shaft.