JPH0637573U - Swash plate type fluid pump / motor - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the running cost and manufacturing cost and improve the processing accuracy of the center height of the fulcrum member 58. [Configuration] When the opening edge and the bottom of the insertion hole 60 are crushed by repeated tilting of the swash plate 51, only the fulcrum body 59, which is a small component, needs to be replaced, so that the running cost is reduced. Further, since the fulcrum body 59 does not have any obstructive protrusions, the processing accuracy of the center height can be increased. Further, since each fulcrum body 59 can be formed by dividing the fulcrum body 59 having a circular cross section into two parts, the manufacturing cost is low.

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, one described in Japanese Utility Model Publication No. 4-24147 is known. In this device, a swash plate that receives a pressing force from the front of each plunger of the cylinder block connected to the output shaft is supported by a predetermined plane of the main body on the back side, and the swash plate is provided at two positions on the predetermined plane. In a swash plate type hydraulic motor in which the rotational speed is changed by tilting a predetermined angle from the predetermined plane side by a hydraulic cylinder device around a single fulcrum formed by both sides, the swash plate that constitutes the fulcrum The supporting mechanism has two fulcrum members having a hemispherical portion and a short columnar portion having a cross section smaller than the flat surface protruding from a flat surface on the opposite side of the convex spherical surface, and the swash plate or the fixed plane. At one of the two fulcrum points, a concave spherical surface is provided so as to receive the convex spherical surface of the hemispherical portion in surface contact with each other, and on the other side facing the concave spherical surface, the short columnar portion is provided. Center of both said concave spheres in the radial direction And two recesses which are provided so as to fit I also afford to absorb dimensional errors, is made of.

[0003]

[Problems to be solved by the device]

 However, in such a conventional swash plate type fluid motor, when the short columnar part of the fulcrum member is tilted in the recess due to the tilting movement of the swash plate, the recess of the main body or the swash plate is The opening edge and the bottom may be pressed and collapsed by this inclined short columnar part, but if a part of the concave part is collapsed in this way, the fulcrum member will move beyond the design value, so that the output shaft The rotation speed deviates from the design value. Therefore, if the above-described crush occurs, it is necessary to replace the main body or the swash plate as a whole, and as a result, the running cost becomes high. Also, the center height of the convex spherical surface of the fulcrum member, that is, the distance from the circular flat surface of the hemispherical portion to the uppermost end of the convex spherical surface is a very important numerical value for determining the stroke of the plunger. Since an extra short columnar part is integrally provided in the hemispherical part, it is difficult to sufficiently improve the processing accuracy because the short columnar part interferes with the forming process. There is also. Further, since the fulcrum member is composed of the hemispherical portion and the short columnar portion, when the short columnar portion is cut out from the raw material, many materials become scraps, which causes a problem of high manufacturing cost.

An object of the present invention is to provide a swash plate type fluid pump / motor that can reduce running costs and manufacturing costs and can improve the processing accuracy of the center height of a fulcrum member.

[0005]

[Means for Solving the Problems]

 The purpose is to tilt the swash plate about the tilting line connecting the two fulcrum members supported by the casing, and thereby to make the stroke of the plunger in the cylinder block slidably contacting the inclined surface of the swash plate. In the swash plate type fluid pump / motor that has been changed, the fulcrum body in which each fulcrum member has a substantially semicircular cross section taken along a plane perpendicular to the tilting line and an insertion hole is formed in a flat bottom surface. A fulcrum shaft inserted into the insertion hole, and one of the rear surface of the swash plate on the opposite side of the inclined surface or the facing surface of the casing facing the rear surface, and the surface of the fulcrum body is convex. It comprises at least one of the fulcrum shaft and a concave hole having a concave curved surface to be in contact with, and a fixing hole which is provided on the other of the back surface or the opposite surface and into which the other side of the fulcrum shaft is inserted and fixed. Can be accomplished by inserting in a loosely into insertion holes of the fulcrum main body.

[0006]

[Action]

 In this invention, it is the fulcrum body that may tilt due to the tilting movement of the swash plate, and the crushing of the fulcrum body due to the tilting of the fulcrum body causes the opening edge of the insertion hole of the fulcrum body pressed by the fulcrum shaft and Since it is at the bottom, only the fulcrum body, which is a small component, needs to be replaced when such a crush occurs, resulting in low running costs. In addition, the processing accuracy of the center height of the convex curved surface and the distance from the flat bottom surface to the uppermost end of the convex curved surface is sufficient because it is processing for the fulcrum body without any obtrusive protrusions such as short columnar parts. Can be improved. Furthermore, since the fulcrum body has a semi-circular cross section taken along a plane perpendicular to the tilting straight line that is the tilting center, it is possible to mold a circular cross-section into two parts. Almost no waste is generated and the manufacturing cost is low.

[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). 31 is a ring-shaped plate fixed to the bottom surface of the storage chamber 23, that is, one end surface, and the other end surface 32 of this plate 31 is a flat surface positioned on a plane perpendicular to the axis of the rotating shaft 28. ing. The case body 22, the side plate 24, and the plate 31 described above collectively constitute a casing 33 of the fluid motor 21.

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.

In FIGS. 1, 2, and 3, reference numeral 51 denotes a substantially ring-shaped swash plate arranged between one end surface of the cylinder block 38 and one end inner surface of the casing 33, more specifically, the other end surface 32 of the plate 31. The rotary shaft 28 penetrates through the swash plate 51. 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 of the rotary shaft 28, and as a result, the swash plate 51 has a thick portion with the central portion as a boundary. It can be divided into a thin portion 53 and a thin portion 54. Also, the back surface (one end surface opposite to the tilted surface 52) 55 of the swash plate 51 facing the other end surface 32 of the plate 31 is positioned on the thick portion 53 side substantially parallel to the vertical surface with respect to the axis of the rotating shaft 28. A first flat surface 56 and a second flat surface 57 that is inclined to the first flat surface 56 at a predetermined small angle A and is located on the thin-walled 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 to the thick portion 53 side by a predetermined distance.

Reference numeral 58 denotes two fulcrum members supported by the casing 33, and a straight line (tilt straight line L) connecting these fulcrum members 58 becomes a tilt center line of the swash plate 51. Here, each fulcrum member 58 has a substantially semicircular cross section taken along a plane perpendicular to the tilting straight line L, and the cross section taken along a plane including the tilting straight line L is also substantially semicircular here. It has a fulcrum body 59 having a substantially hemispherical shape, and an insertion hole 60 perpendicular to the bottom surface 59a is formed at the center of the flat bottom surface 59a of each fulcrum body 59. 61 is a cylindrical fulcrum shaft inserted into the insertion hole 60 on one side, and at least one of these fulcrum shafts 61, here the radii of both fulcrum shafts 61 are slightly smaller than the inner radius of the insertion hole 60. Moreover, in this embodiment, it is smaller by about 0.05 to 0.15 mm, and as a result, both of these fulcrum shafts 61 are inserted into the insertion holes 60 in a loosely fitted state. On the other hand, on the boundary between the first and second flat surfaces 56 and 57, two recesses 63 having a substantially hemispherical recessed curved surface 63a are formed on the back surface 55 of the swash plate 51. It is arranged at a predetermined distance in the extending direction of the boundary. Then, the hemispherical convex curved surfaces 59b of the fulcrum body 59 are respectively inserted into the concave portions 63 in a state of being in spherical contact with the concave curved surface 63a. It is in surface contact with the end face 32. Further, columnar fixing holes 64 are formed in the other end surface 32 of the plate 31 (the facing surface facing the back surface 55 of the swash plate 51) at a position facing the recesses 63, and these fixing holes 64 have the above-mentioned fixing holes 64, respectively. The other side of the fulcrum shaft 61 is inserted and fixed. Here, when each fulcrum shaft 61 is inserted and fixed in the fixing hole 64 as described above, 0.1 mm or more is provided between one end surface (tip end surface) of the fulcrum shaft 61 and the bottom surface of the insertion hole 60. Gaps are formed. The fulcrum body 59, the fulcrum shaft 61, the recess 63, and the fixing hole 64 as a whole constitute the fulcrum member 58, and the swash plate 51 has these two fulcrum members 58, more specifically, the fulcrum body 59. The first tilted position F (see FIG. 2) where the second flat surface 57 and the other end surface 32 of the plate 31 are in surface contact with each other around the straight line (the tilted straight line L) connecting the centers of curvature of the convex curved surfaces 59b of FIG. (Shown by a solid line) and a second tilting position G (shown by a virtual line in FIG. 2) where the first flat surface 56 and the other end surface 32 of the plate 31 are in surface contact with each other. can do. Here, as described above, since at least one of the fulcrum shafts 61 is inserted into the insertion hole 60 of the fulcrum body 59, here, both fulcrum shafts 61 are loosely fitted, the distance P between the centers of curvature of the recesses 63 (the fulcrum body 59) and the center distance Q of the fixing hole 64 (the same as the center axis distance of the fulcrum shaft 61) are slightly different due to manufacturing errors, etc. Since the above difference can be absorbed by the play, the fluid motor 21 can be easily processed and assembled, and vibration during operation can be prevented.

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. The retainer plate 73 is arranged between the cylinder block 38 and the swash plate 51 and engages with all the shoes 70. is doing. Reference numeral 74 denotes a thrust ball arranged between the cylinder block 38 and the retainer plate 73, and the outer surface of the thrust ball 74 on the side close to the retainer plate 73 is composed of a part of a spherical surface. The outer surface of the thrust ball 74 makes spherical contact with the inner circumference of the retainer plate 73, and the thrust ball 74 is fitted to the outside of the rotary shaft 28 and connected by spline connection. 75 is a spring interposed between the cylinder block 38 and the thrust ball 74.The spring 75 presses the shoe 70 against the inclined surface 52 of the swash plate 51 via the thrust ball 74 and the retainer plate 73, The shoe 70 is prevented from rising from the inclined surface 52.

A cylinder chamber 80 is formed inside the casing 33 that faces the second flat surface 57 of the swash plate 51, specifically, the case body 22 and the plate 31, and a pressing piston 82 rotates inside the cylinder chamber 80. It is inserted so as to be movable in the axial direction of the shaft 28. The pressing piston 82 has a small-diameter rod portion 83 whose tip abuts against the back surface 55 (second flat surface 57) of the thin portion 54 of the swash plate 51. 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 with the rod portion 83 abutting the thin-side rear surface 55 of the swash plate 51. In order to move, the swash plate 51 tilts from the first tilting position F to the second tilting position G about the tilting straight line L, while the supply of the high pressure fluid to the cylinder chamber 80 is stopped, Since the tilting straight line L is offset from the center of the swash plate 51 to the thick portion 53 side, the swash plate 51 is tilted from the second tilting position G to the first tilting position F by the pressing force from the plunger 40. To do. 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.

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 engages with the inclined surface 52 of the swash plate 51 via the shoe 70 and becomes thicker 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 via the thrust ball 74 and the retainer plate 73, so that the fluid in the cylinder hole 39 is discharged. However, the shoe 70 does not rise above the inclined surface 52.

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 L is offset from the center of the swash plate 51 to the thick portion 53 side, the swash plate 51 is pressed by the plunger 40 so that the swash plate 51 has the second flat surface 57 and the other end surface. It is tilted to the first tilting position F 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 rotational speed of the cylinder block 38 and the rotary 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, the high-pressure fluid is supplied to the cylinder chamber 80 through the fluid passage 84, and the pressing piston 82 is moved to the swash plate 51 while the rod portion 83 is kept in contact with the back surface 55 of the thin portion 54 of the swash plate 51. Move towards. As a result, the swash plate 51 is pushed by the pressing piston 82 and the second tilting position G where the first flat surface 56 and the other end surface 32 come into surface contact with each other about the tilting straight line L from the first tilting position F. Tilt up to. 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.

When the swash plate 51 is repeatedly tilted as described above, the fulcrum body 59 is repeatedly tilted with this tilting motion, and the fulcrum shaft 61 is inserted into the insertion hole 60 of the fulcrum body 59 at each tilt. Since the opening edge and the bottom portion are in contact with and strongly pressed, the opening edge and the bottom portion of the insertion hole 60 may be crushed. Here, if such a crush occurs, the fulcrum body 59 moves more than the design value, so that the rotation speed of the rotary shaft 28 may deviate from the design value. In order to prevent such a situation, the crushed parts must be replaced, but in this embodiment, only the fulcrum body 59, which is a small part, needs to be replaced, so the running cost is low. It becomes. Further, the center height H of the convex curved surface 59b of the fulcrum body 59, that is, the distance from the flat bottom surface 59a to the uppermost end of the convex curved surface 59b is a very important numerical value for determining the stroke of the plunger 40. Although high precision is required, the fulcrum body 59 does not have any obstructive protrusion, for example, a short columnar portion, so that the machining precision can be easily increased. Furthermore, since each fulcrum body 59 has a substantially semicircular cross section taken along a plane perpendicular to the tilting straight line L which is the tilting center, it is possible to mold a circular cross section into two parts. As a result, almost no cutting chips are generated, and the manufacturing cost is low.

In the above embodiment, the fulcrum body 59 has a substantially hemispherical shape, but in the present invention, as shown in FIG. 4, a cross section taken along a plane perpendicular to the tilting straight line L has a semicircular shape, The cross section taken along a plane including the tilted straight line L may be rectangular and the entire shape may be substantially semicylindrical. In this case, the recess 63 also has a substantially semi-cylindrical shape. Further, in the above-described embodiment, one side of both fulcrum shafts 61 is inserted into the insertion hole 60 of the fulcrum body 59 in a loosely fitted state, but in this invention, as shown in FIG. , One fulcrum shaft 61 is loosely inserted into the insertion hole 60 of the fulcrum body 59, and the other fulcrum shaft 61 is inserted into the insertion hole 60 of the fulcrum body 59 with the inner and outer surfaces being in surface contact or It may be inserted with a very small gap between them. Further, in the above-mentioned embodiment, the recess 63 in which the fulcrum body 59 makes surface contact with the back surface 55 of the swash plate 51, the fulcrum shaft 61 is inserted and fixed in the facing surface of the casing 33, specifically, the other end surface 32 of the plate 31. Although the fixing hole 64 is provided in the present invention, in the present invention, the concave surface with which the fulcrum body is in surface contact is provided on the facing surface of the casing, and the fixing hole into which the fulcrum shaft is inserted and fixed is provided on the back surface of the swash plate. Good. Further, in the above-described embodiment, the back surface 55 of the swash plate 51 is composed of two flat surfaces 56 and 57 intersecting at a predetermined angle A, and the facing surface (the other end surface 32) of the casing 33 facing the back surface 55. In the present invention, the back surface 55 of the swash plate 51 is composed of one flat surface, and the opposing surface of the casing 33 is composed of two flat surfaces intersecting at a predetermined angle A. You may do it. Further, in the above-described embodiment, the back surface 55 of the swash plate 51 is composed of two flat surfaces 56 and 57, but in the present invention, it is composed of three flat surfaces and the swash plate 51 is tilted into three tilt surfaces. It may be tilted between the positions. Further, although the invention is applied to the fluid motor 21 in the above-described embodiments, the invention may be applied to the fluid pump.

[0018]

[Effect of device]

 As described above, according to this invention, the running cost and the manufacturing cost can be reduced, and the processing accuracy of the center height of the fulcrum member can be improved.

[Brief description of drawings]

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

FIG. 2 is a front sectional view in the vicinity of a swash plate.

3 is a cross-sectional view taken along the line II of FIG.

FIG. 4 is a perspective view of a fulcrum body showing another embodiment of the present invention.

FIG. 5 is a sectional view similar to FIG. 3 showing still another embodiment of the present invention.

[Explanation of symbols]

 21 ... Swash plate type fluid motor 32 ... Opposing surface 33 ... Casing 38 ... Cylinder block 40 ... Plunger 51 ... Swash plate 52 ... Inclined surface 55 ... Rear surface 58 ... Support point member 59 ... Support point body 59a ... Bottom surface 59b ... Convex curved surface 60 ... Insertion hole 61 ... fulcrum shaft 63 ... concave portion 63a ... concave curved surface 64 ... fixing hole L ... tilting line F, G ... tilting position

Claims (1)

[Scope of utility model registration request] 1. Two fulcrum members supported by a casing 33.
By tilting the swash plate 51 about the tilting straight line L connecting the 58, the stroke of the plunger 40 in the cylinder block 38 slidingly contacting the tilted surface 52 of the swash plate is changed. In the motor 21, each fulcrum member has a substantially semicircular cross section taken along a plane perpendicular to the tilt line, and a fulcrum body 59 having an insertion hole 60 formed in a flat bottom surface 59a, and one side of the fulcrum body 59. Fulcrum shaft 61 inserted in the hole
And a concave portion 63 having a concave curved surface 63a provided on either the rear surface 55 on the side opposite to the inclined surface of the swash plate or the facing surface 32 of the casing facing the rear surface, and having a concave curved surface 63a that makes surface contact with the convex curved surface 59b of the fulcrum body. , A fixing hole 64 provided on the other side of the back surface or the opposite surface and the other side of the fulcrum shaft is inserted and fixed
And a swash plate type fluid pump / motor, wherein at least one of the fulcrum shafts is inserted into the insertion hole of the fulcrum body in a loosely fitted state.