JP2600832Y2 - Swash plate type fluid pump / motor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type fluid pump motor in which the stroke of a plunger is changed by tilting a swash plate.

[0002]

2. Description of the Related Art As a conventional swash plate type fluid motor, for example, one described in Japanese Patent Publication No. 4-42550 is known. This is formed on a casing, a rotating shaft rotatably supported by the casing, a cylinder block housed in the casing and connected to the rotating shaft so as to be integrally rotatable, and formed on one end surface of the cylinder block. A plunger slidably inserted into each of a plurality of axially extending cylinder holes, a tiltable swash plate disposed between one end surface of the cylinder block and an inner surface of one end of the casing; Tilting means for tilting between two tilting positions, and slidably contacting an inclined surface located at the other end of the swash plate,
A plurality of shoes respectively connected to one end of the plunger via a ball joint, a loosely fitted retainer plate which is loosely fitted to the outside of the rotating shaft and engages with the shoe, and A thrust ball having a spherical portion on the outer periphery, the spherical portion being made of a part of a spherical surface protruding in a convex shape toward one side and being in spherical contact with the inner periphery of the retainer plate, and a curvature of the spherical portion of the thrust ball. The center is located on the intersection of the plane connecting the centers of the balls of the ball joint and the axis of the rotation axis.

[0003]

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 ball 15 of the ball joint 14 as described above. Since it is located on the intersection K between the plane H connecting the centers S and the axis L of the rotating shaft 13 (see FIG. 3), the thrust ball 11 is arranged close to the swash plate 16. As a result, the spherical portion 12 of the thrust ball 11 and the inner peripheral end of the swash plate 16 adjacent to 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. Inevitably, the inclination angle G at the portion must be reduced. As a result, the plunger when the swash plate 16 is at one tilt position
The difference between the stroke of 17 and the stroke of the plunger 17 when the swash plate 16 is at the other tilt position is reduced, and the fluctuation range of the rotation speed of the cylinder block 18 and the rotating shaft 13 is reduced. is there.

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 a cylinder block and a rotating shaft.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a casing, a rotating shaft rotatably supported by the casing, and a cylinder block housed in the casing and connected to the rotating shaft so as to be integrally rotatable therewith. And a plunger slidably inserted into a plurality of axially extending cylinder holes formed in one end surface of the cylinder block, and a tilt disposed between one end surface of the cylinder block and one inner surface of the casing. A possible swash plate, a tilting means for tilting the swash plate, and a plurality of shoes which are in sliding contact with an inclined surface located at the other end of the swash plate and respectively connected to one end of the plunger via a ball joint. A substantially ring-shaped retainer plate that is loosely fitted to the outside of the rotation shaft and engages with the shoe; and a spherical surface fitted to the outside of the rotation shaft and protruding toward one side. A thrust ball having a spherical portion on the outer periphery, which is formed in part and makes spherical contact with the inner periphery of the retainer plate, wherein the stroke of the plunger is changed by tilting the swash plate by the tilting means. In the swash plate type fluid pump / motor, the center of curvature of the spherical portion of the thrust ball is positioned on the axis of the rotation axis on the other side from the intersection of the axis of the rotation axis and the plane connecting the ball centers of the ball joints. Can be achieved.

[0006]

In this invention, as shown in FIG. 2, the center of curvature C of the spherical portion 12 of the thrust ball 11 is changed to the ball joint 14
Is located on the axis L of the rotation shaft 13 on the other side of the intersection K between the plane H connecting the centers S of the spheres 15 and the axis L of the rotation shaft 13, for example, at a predetermined distance M from the intersection K. For,
The thrust ball 11 is separated from the swash plate 16 so that a certain amount of extra space is formed between the swash plate 16 and the swash plate 16. As a result, the tilt angle T of the swash plate 16, the minimum thickness N in the thin portion of the swash plate 16 and the spherical surface Part 12
Under the condition that the radius of curvature R of the swash plate 16 is constant, the inclination angle G of the thick portion of the swash plate 16 is
While preventing interference between the swash plate 16 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 a different tilt position increases, and as a result, the fluctuation range of the rotation speed of the cylinder block 18 and the rotation shaft 13 increases.

[0007]

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 main body 22, and the other end surface of the case main 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 body 22,
As a result, the storage chamber 23 is closed by the side plate 24 to form a closed space. Reference numeral 28 denotes a rotating shaft whose other side is inserted into the storage chamber 23, and the rotating shaft 28 includes a pair of bearings 29,
It is rotatably supported by the side plate 24 and the case body 22 via 30. One end of the rotating shaft 28 is
And is connected to a sprocket that engages with a crawler (not shown). The above-described case body 22 and side plate 24 are formed as a whole with a casing 33 of the fluid motor 21.
Is configured.

Reference numeral 38 denotes a cylindrical cylinder block housed in the storage chamber 23. The other end of the rotary shaft 28 is inserted into the cylinder block 38 and spline-coupled, so that the cylinder block 38 The rotation shaft 28 is connected so as to be able to rotate integrally. This cylinder block 38
A plurality of cylinder holes 39 extending in the axial direction are formed on one end surface of the cylinder, and these cylinder holes 39 are arranged at equal distances in the circumferential direction. In these cylinder holes 39, cylinder holes 39
And the same number of plungers 40 are slidably inserted, respectively.
A spherical sphere 41 is formed at the tip of each plunger 40, that is, at one end. 42 is fixed to the side plate 24 and is a cylinder block
A timing plate located between the side plate 24 and the side plate 24. The timing plate 42 is formed with two long arcuate holes 43 spaced apart in the circumferential direction. It is connected one after another by the rotation of 38. Reference numerals 44, 45 denote 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. In addition, these supply and exhaust passages
Reference numerals 44 and 45 are connected to a pump and a tank via a switching valve (not shown), and when the switching valve is switched, either one 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 face of the cylinder block 38 and one end face (the bottom face of the storage chamber 23) 32 of the casing 33. 28 penetrates. The cylinder block 38 of the swash plate 51
Is inclined with respect to a plane perpendicular to the axis L of the rotating shaft 28. As a result, the swash plate 51 is divided into a thick portion 53 and a thin portion 54 with the center portion as a boundary. be able to. A rear surface 55 of the swash plate 51 facing the inner surface 32 at one end (an end surface opposite to the inclined surface 52) 55 is located on the side of the thick portion 53 substantially parallel to a plane perpendicular to the axis L of the rotating shaft 28. A first flat surface 56 and a second flat surface 57 inclined at a predetermined small tilt angle T with respect to the first flat surface 56 and located on the thin portion 54 side.
The boundary between the first and second flat surfaces 56 and 57 is separated from the center of the swash plate 51 by a predetermined distance toward the thick portion 53.

Reference numeral 58 denotes two spherical fulcrum members. A straight line (tilt line) connecting the centers of the spheres of the fulcrum members 58 becomes the tilt center line of the swash plate 51. Here, each fulcrum member 58 is formed on the back surface 55 on the boundary between the first and second flat surfaces 56 and 57.
Half of the half-spherical recesses 63 are inserted into two hemispherical recesses 64 formed on the inner surface 32 at one end facing the recesses 63 while the other half is in spherical contact. . As a result, the swash plate 51 has a first inclination where the second flat surface 57 and one end inner surface 32 are in surface contact with each other about a straight line (the tilting straight line) connecting the centers of the spheres of the two fulcrum members 58. The second flat position where the first flat surface 56 and one end inner surface 32 are in surface contact with each other.
It is possible to tilt between the tilt positions.

Reference numeral 70 denotes the same number of shoes as the plunger 40,
A ball hole in which the ball portion 41 of the plunger 40 is stored in each shoe 70
71 are formed. The above-mentioned ball portion 41 and ball hole 71 constitute a ball joint joint 72 as a whole, whereby one end of the plunger 40 and the shoe 70 are connected via the ball joint joint 72. These shoes 70 are provided on the inclined surface 52 of the swash plate 51.
Is slidably engaged with. Reference numeral 73 denotes a substantially ring-shaped retainer plate loosely fitted to the outside of the rotary shaft 28, and the retainer plate 73 is disposed between the cylinder block 38 and the swash plate 51. The retainer plate 73 is engaged with all the shoes 70, and the inner periphery 76 is formed of a part of a spherical surface gradually expanding toward the other. Reference numeral 74 denotes a thrust ball disposed between the cylinder block 38 and the retainer plate 73, and the thrust ball 74 has a spherical portion 77 on the outer periphery which is a part of a spherical surface protruding toward one side. The spherical portion 77 is in spherical contact with the inner periphery 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. Reference numeral 75 denotes a spring as a biasing member interposed between the cylinder block 38 and the thrust ball 74.
75 urges the shoe 70 against the inclined surface 52 of the swash plate 51 by urging the thrust ball 74 and the retainer plate 73 toward the swash plate 51. The center of curvature C of the spherical portion 77 of the thrust ball 74 is defined by the spherical center S of the ball joint 72.
That is, it is located on the axis L of the rotating shaft 28 on the other side of the intersection K between the plane H connecting the centers of curvature of the spherical portions 41 and the axis L of the rotating shaft 28.

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. Have been. 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
The swash plate 51 moves toward the swash plate 51 while being in contact with the thin-side back surface 55 of the swash plate.
When the tilting position is tilted from the tilting position to the second tilting position and the supply of the high-pressure fluid to the cylinder chamber 80 is stopped, the tilting straight line
The swash plate 51 is tilted from the second tilt position to the first tilt position by the pressing force from the plunger 40 because the swash plate 51 is offset from the center of the 51 to the thick portion 53 side. As a result, the stroke of the plunger 40 in the cylinder block 38 is changed in two steps, and the rotation speeds of the cylinder block 38 and the rotating shaft 28 are changed in two steps. The above-described cylinder chamber 80, the pressing piston 82, and the fluid passage 84 as a whole constitute 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 to the cylinder hole 39 of the cylinder block 38 through the one arc-shaped hole 43, the plunger 40 in the cylinder hole 39 projects toward the swash plate 51 and presses the inclined surface 52. At this time, plunger
Since the tip of 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 53
Side to the thin-walled part 54 side, and these plungers
The cylinder 40, the cylinder block 38, and the rotating 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 arc-shaped hole 43 becomes
While moving from the thin part 54 side to the thick part 53 side while engaging with the inclined surface 52 of the swash plate 51 via the shoe 70, the inclined surface 52 is gradually pushed into the cylinder hole 39 by the inclined surface 52. The fluid in the cylinder hole 39 is pushed out, and the other arc-shaped hole 43, the supply / discharge passage
Discharge through 45. At this time, since the shoe 70 is pressed against the inclined surface 52 of the swash plate 51 by the urging force of the spring 75 transmitted via the thrust ball 74 and the retainer plate 73, the shoe 70 may come off the plunger 40 due to centrifugal force. The fluid motor 21 acts as a pump and the plunger 40
This prevents the shoe 70 from rising off the inclined surface 52 of the swash plate 51 when drawing fluid.

Here, for example, when the crawler vehicle is climbing a hill, 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, since the tilt straight line is offset from the center of the swash plate 51 toward the thick portion 53 as described above, the swash plate 51 is pressed against the second flat surface 57 and the inner surface 32 at one end by the pressing force from the plunger 40. Have tilted to the first tilt position where they make surface contact. At this time, the cylinder block
Although the stroke of the plunger 40 in 38 becomes long, since the amount of high-pressure fluid flowing into the fluid motor 21 is constant, the rotation speed of the cylinder block 38 and the rotating shaft 28 becomes low.

Next, when the crawler vehicle travels, for example, on a level ground, 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 keeping the pressing piston 82 in contact with the back surface 55 of the thin portion 54 of the swash plate 51. This allows the swash plate
51 is pushed by the pressing piston 82 and centered on the tilt straight line,
It tilts from the first tilt position to a second tilt position where the first flat surface 56 and one end inner surface 32 are in surface contact. This shortens the stroke of the plunger 40 in the cylinder block 38,
The cylinder block 38 and the rotating shaft 28 rotate at high speed.

If the center of curvature C of the spherical 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 moves away from the swash plate 51. As a result, a certain amount of extra space is created between the swash plate 51 and the tilt angle T of the swash plate 51, the minimum thickness N of the thin portion 54 of the swash plate 51, and the radius of curvature R of the spherical portion 77 are constant. Under the condition that the inclination angle G of 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, the inner peripheral surface of the spherical portion 77 of the thrust ball 74 and the swash plate 51 The size can be increased while preventing interference with the ends. Thereby, the stroke difference of the plunger 40 when the swash plate 51 is in the different tilting positions, that is, in the first tilting position and the second tilting position, becomes large, and the cylinder block 38 and the rotating shaft in these tilting times become large.
The fluctuation range of the rotation speed of 28 becomes large.

In the above-described embodiment, two flat surfaces 56 and 57 intersecting the back surface 55 of the swash plate 51 at a predetermined tilt angle T.
The inner surface 32 at one end of the casing 33 opposed to the rear surface 55 is constituted by one flat surface. In the present invention, the rear surface 55 of the swash plate 51 is constituted by one flat surface, and one end of the casing 33 is formed. The inner surface may be composed of two flat surfaces that intersect at a predetermined tilt angle T. In the above-described embodiment, the rear surface 55 of the swash plate 51 is connected to the two flat surfaces 56 and 57.
However, in the present invention, the back 55 of the swash plate 51
May be composed of three flat surfaces, and the swash plate 51 may be tilted between the three tilt positions. Further, in the above-described embodiment, the present invention is applied to the fluid motor 21, but the present invention may be applied to a fluid pump.

[0018]

As described above, according to the present invention, the fluctuation range of the rotation speed of the cylinder block and the rotating shaft can be increased.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram illustrating the principle of the present 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 ... Sloped surface 70 ... Shoe 72 ... Ball 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 K ... Intersection

Claims (1)

(57) [Scope of request for utility model registration] 1. A casing 33, a rotating shaft 28 rotatably supported by the casing, a cylinder block 38 housed in the casing and connected to the rotating shaft so as to be integrally rotatable, and one end face of the cylinder block. Plunger 40 slidably inserted into a plurality of axially extending cylinder holes 39 formed in the cylinder block, and a tiltable swash plate disposed between one end face of the cylinder block and one inner face 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 via a ball joint 72. A substantially ring-shaped retainer plate 73 which is loosely fitted to the outside of the rotation shaft and engages with the shoe;
A thrust ball 74, which is fitted on the outside of the rotation shaft and has a spherical portion 77 on the outer periphery, which is formed of a part of a spherical surface protruding in a convex shape toward one side, and has a spherical portion 77 which is in spherical contact with the inner periphery 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 changed by a ball joint. A swash plate type fluid pump motor characterized in that the swash plate type fluid pump / motor is located on the axis of the rotating shaft on the other side of the intersection K between the plane H connecting the spherical centers S of the joints and the axis L of the rotating shaft.