JP4762714B2 - Swash plate type piston motor - Google Patents

Description

  The present invention relates to a swash plate type piston motor, and more particularly to an apparatus for supplying lubricating oil to a bearing portion thereof.

  In a hydraulic motor such as a swash plate type piston motor, the rotating shaft is usually provided with two bearing portions. Of these, bearings arranged farther from the output side have various considerations for lubrication due to the arrangement of the bearing portion inside the hydraulic motor. For example, in order to improve the maintenance and management efficiency of the lubricating oil and reduce costs, the hydraulic motor is lubricated with drain oil accumulated in the case due to internal leakage of the hydraulic oil, and the gear type reduction gear is lubricated. Is a lubricating device for a hydraulic motor speed reducer configured to be performed by lubricating oil contained in a housing, and an oil communication path means is provided between the case and the housing, and the housing and the oil tank Has been proposed to be connected by a drain pipe (see FIG. 1 of Patent Document 1).

  In addition, a spiral groove is formed in the outer peripheral portion of the portion where the rotary shaft of the hydraulic motor faces the inner peripheral portion of the through hole of the valve plate in order to perform forced lubrication in order to extend the life of the bearing. The end surface of the rear bearing that supports the shaft communicates with the vicinity of the outer peripheral portion of the valve plate by an oil passage provided in the valve casing, and between the valve plate and the end surface of the cylinder block, the spiral groove is formed on the inner peripheral side. Since the hydraulic oil leaks around the periphery of the oil passage around the periphery, even if the rotating shaft rotates in either direction, the hydraulic oil that leaks to the inner circumference or the hydraulic oil that leaks to the outer circumference is oil. A configuration for forcibly lubricating the rear bearing through the road and the rear bearing has been proposed (see FIG. 1 of Patent Document 2).

  FIG. 3 shows another lubrication system for the rear bearing (Patent Document 3).

  A sectional view showing the internal structure of the swash plate type piston motor of Patent Document 3 is shown in FIG. 3 of the present application. In FIG. 3, the swash plate type piston motor includes a housing 10 formed in a cylindrical shape with an open rear end, and a housing cover 11 that closes the rear end opening of the housing 10. The swash plate 12, the piston 14, the cylinder block 16, the valve plate 18, the motor shaft 23, the mechanical brake mechanism 29, and the like are provided.

  The front surface of the swash plate 12 is fixed to the inner surface of the housing 10 with bolts or the like, and a shoe 13 is slidably in contact with the back surface of the swash plate 12. A plurality of pistons 14 are provided in the housing 10. Each piston 14 has a spherical head 15, and is engaged with the shoe 13 through the spherical head 15 so as to be swingable.

  The cylinder block 16 is formed in a columnar shape, and a plurality of cylinder chambers 17 for holding the piston 14 slidably are formed in the cylinder block 16. The valve plate 18 is formed in an annular shape. The valve plate 18 is provided between the cylinder block 16 and the housing cover 11, and a crescent-shaped pressure oil supply / discharge for supplying / exhausting pressure oil to / from the cylinder chamber 17 of the cylinder block 16 is provided in the valve plate 18. Ports 19 and 19 are provided.

  The motor shaft 23 has a retainer portion 24, and a ring-shaped leaf spring 26 that presses the shoe 13 against the swash plate 12 via a return plate 25 is attached to the retainer portion 24. The motor shaft 23 passes through the center hole of the swash plate 12 and is rotatably supported by a boss portion 27 formed at the front end portion of the housing 10 via a bearing 28. Further, the motor shaft 23 is formed integrally with the cylinder block 16 so as to extend from the front end surface of the cylinder block 16.

  The mechanical brake mechanism 29 includes a fixed brake plate 30 fixed to the cylinder block 16, a movable brake plate 31 provided on the outer periphery of the cylinder block 16 so as to face the fixed brake plate 30, and the movable brake plate 31 as a cylinder block. There are provided a brake piston 32 that is advanced and retracted in the 16 axial directions, and a plurality of compression coil springs 33 that press the movable brake plate 31 against the fixed brake plate 30 via the brake piston 32. The mechanical brake mechanism 29 has a brake piston chamber 34. Pressure oil is supplied to the brake piston chamber 34 from a brake release hydraulic timer 35, whereby the brake piston 32 and the movable brake plate 31 are compressed by a coil spring. When it moves backward to the right in the figure against the spring force of 33, the friction brake force generated between the fixed brake plate 30 and the movable brake plate 31 is released. Accordingly, the pressure oil is supplied from the brake release hydraulic timer 35 to the brake piston chamber 34 of the mechanical brake mechanism 29, whereby the movable brake plate 31 and the brake piston 32 are resisted against the spring force of the compression coil spring 33. If it moves to the direction, the brake force with respect to the motor shaft 23 will be cancelled | released, and the cylinder block 16 and the motor shaft 23 will be in the state which can rotate.

  The housing cover 11 is fixed to the housing 10 with bolts or the like, and pressure oil supply ports 20, 20 for supplying and discharging pressure oil to and from the pressure oil supply / discharge ports 19, 19 of the valve plate 18. Pressure oil discharge ports 21 and 21 and a leak oil discharge port 22 for discharging hydraulic oil leaking in the housing 10 to the outside. A cylindrical boss portion 38 is provided on the front end surface of the housing cover 11 so as to engage with a hole portion 36 formed in the rear end surface of the cylinder block 16 via a bearing 37.

  The pressure oil supply ports 20 and 20 and the pressure oil discharge ports 21 and 21 are formed of a large diameter hole opening toward the valve plate 18 and a small diameter hole connected to the rear end of the large diameter hole. A ring-shaped bush 44 is slidably provided in the large-diameter hole portion of each port 20, 21, and an elastic body, preferably a disc spring, that abuts the bush 44 against the back surface of the valve plate 18. A spring 45 is provided.

  Each bush 44 is provided at the large diameter portion with its front end surface slightly protruding from the front end surface of the housing cover 11, and therefore, oil is passed between the housing cover 11 and the valve plate 18. A gap is formed.

  The housing cover 11 is provided with a hydraulic oil introduction hole 40 as hydraulic oil introduction means for introducing hydraulic oil into the gap 39 between the hole 36 and the boss 38 described above. The hydraulic oil introduction hole 40 communicates with the brake release hydraulic timer 35 via the hydraulic oil supply pipe 41 and the throttle 43, and accordingly, the operation supplied to the brake release hydraulic timer 35 is supplied to the hydraulic oil introduction hole 40. Oil is constantly supplied via the throttle 43 and the hydraulic oil supply pipe 41.

  In the swash plate type piston motor configured as described above, the hydraulic oil branched from the brake release hydraulic timer 35, depressurized by the throttle 43, and then the hydraulic oil supplied to the hydraulic oil supply conduit 41 passes through the hydraulic oil introduction hole 40. When the oil is introduced into the gap 39, the oil in the gap 39 flows through the bearing 37 together with the hydraulic oil introduced into the gap 39, and further flows between the housing cover 11 and the valve plate 18; The oil is discharged from the leak oil discharge port 22 of the housing cover 11 to the outside.

  Accordingly, the oil used for lubricating the bearing 37 does not stay in the gap 39 and does not reach a high temperature during high-speed operation. Therefore, the oil film formed on the sliding surface of the bearing 37 has an appropriate thickness. Thus, the wear of the bearing 37 can be suppressed. Further, since the oil used for lubricating the bearing 37 does not stay in the gap 39 and is always discharged to the outside through the leak oil discharge port 22, the sliding surface of the bearing 37 may be damaged by foreign matters such as contamination. Can be suppressed. Thus, in this embodiment, durability of the bearing 37 can be improved. Further, since a part of the oil supplied to the hydraulic timer 35 that releases the braking force of the mechanical brake mechanism 29 by the oil pressure is supplied to the gap 39 from the hydraulic oil introduction hole 40, the hydraulic oil is supplied to the hydraulic oil introduction hole 40. The oil film formed on the sliding surface of the bearing 37 can be maintained at an appropriate thickness without newly providing a hydraulic pump or the like for supplying the oil.

  However, the above-mentioned Patent Document 1 is a hydraulic motor including a reduction gear, and circulates oil in casings on the hydraulic motor side and the reduction gear side. Moreover, in said patent document 2, the helical groove is formed in a rotating shaft part, and the oil in a casing is supplied to a back bearing part using the pump action accompanying rotation of a shaft. In these Patent Documents 1 and 2, oil in the casing is used as lubricating oil, and a pump action is required inside the casing.

  Further, although the above Patent Document 3 does not require a pumping action in the casing, as described above, pressure oil for braking (usually using a pilot pressure source and about 4 MPa) is introduced. It is too high as pressurized oil for the supply. Furthermore, although not shown, piping to the inlet 40 is required. Furthermore, some swash plate type piston motors are not equipped with a brake device. In such a case, it is necessary to provide the piping separately from the pilot pump side, which is complicated and requires a pilot pressure. There is a problem that an oil source is always required.

[Patent Document 1] Japanese Patent Laid-Open No. 8-31521 Name of Invention “Lubrication Device for Hydraulic Motor Reducer” [Patent Document 1] Japanese Patent Laid-Open No. Hei 9-184472 Title of Invention “Hydraulic motor bearing forced lubrication structure” JP 2002-39047 A Title of Invention “Swash Plate Type Piston Motor”

  As a result of intensive studies to solve the problem in Patent Document 3 among Patent Documents 1, 2, and 3 described above, the present inventor uses the pressure oil pressure at the makeup port portion of the swash plate type piston motor. I found out that the problem can be solved basically.

  Therefore, an object of the present invention is to use an appropriate pressure oil as a lubricating oil in a bearing portion inside the motor without requiring piping from the outside and regardless of whether or not the hydraulic motor is equipped with a brake device. The object is to provide a swash plate type piston motor to be supplied.

  In order to achieve the above object, a swash plate type piston motor according to the present invention is supported at one end side through a first bearing at the front casing and at the center of the front casing, and has a large diameter at the other end. A plurality of pistons are arranged in the circumferential direction in the section, and an output rotating shaft formed with a recessed portion opened on the rear side in the central portion, and a projecting portion that fits into the recessed portion are formed. A rear casing having a make-up port connected to a hydraulic circuit that forms a supply pressure oil chamber and a return chamber and suppresses cavitation, and an output disposed between the outer peripheral surface of the convex portion and the inner peripheral surface of the concave portion A swash plate type piston motor having a second bearing for supporting a rear side of the rotating shaft, wherein one side of the convex part is communicated with the inside of the concave part, and the other side is provided with the make-up side. Characterized in that the opening is formed with a through passage in the make-up port passage in said hydraulic circuit leading to Pupoto.

  In that case, it is preferable to provide a throttle in the through passage.

  The throttle can be formed by screwing a throttle member having a hole having a diameter smaller than the inner diameter of the through-passage into an internal thread portion formed at an end of the through-passage on the concave side.

  According to the swash plate type piston motor of the present invention, one end side is supported via the first bearing at the front casing and the central portion of the front casing, and the other end side thicker portion has a circumferential direction. A plurality of pistons are disposed at the center thereof, and an output rotating shaft formed with a recessed portion that opens to the rear side at the center thereof, and a protruding portion that fits into the recessed portion is formed, and the supply pressure oil chamber and the return to the piston are formed. A rear casing having a make-up port connected to a hydraulic circuit that forms a chamber and inhibits cavitation, and a rear side of an output rotation shaft disposed between the outer peripheral surface of the convex portion and the inner peripheral surface of the concave portion. A swash plate type piston motor having a second bearing for supporting the hydraulic circuit, wherein one side of the convex portion communicates with the inside of the concave portion and the other side communicates with the makeup port. Since the through-passage opened in the intake port passage is formed, there is no need for piping from the outside for supplying the lubricating oil to the second bearing, and the lubricating oil supply side for the second bearing is the makeup port. Therefore, it is possible to lubricate the second bearing regardless of the presence or absence of the brake portion.

  Hereinafter, an example based on an embodiment of the invention will be described in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 100 denotes a swash plate type piston motor, and an output rotary shaft 50 is provided at the front case 66 at the center of the left end portion. It is supported inside the front casing 66 by a bearing 50B through an oil seal 50A. The right end side of the output rotating shaft 50 is formed with a large diameter, and a plurality of pistons 54 are arranged in the circumferential direction. Reference numerals 52 and 62 are a swash plate and a brake part as described in FIG. A concave portion 60 is formed in the central portion of the output rotating shaft 50 having a large diameter on the right end side, and is fitted into the central convex portion 58 of the rear end casing 66A on the right end side. A needle bearing 56, which is a rear bearing of the output rotating shaft 50, is attached between the outer peripheral surface of the convex portion 58 and the inner peripheral surface of the concave portion 60.

  Reference numeral 64 is a through passage provided in the center of the rear casing 66A. The left end side of the passage 64 communicates with the inside of the recess 60 through the restrictor 60A, and the right end side of the passage 64 is a makeup line indicated by a thick solid line of the hydraulic circuit 68 for suppressing cavitation leading to the makeup port MP. It opens and communicates with the port passage MPL.

  The cavitation suppressing hydraulic circuit 68 is formed of a pair of relief valves RF1 and RF2 and a pair of check valves CH1 and CH2, and communicates with a makeup port MP. Reference numeral 66B represents a casing end portion of the rear casing 66A, and is shown as having the hydraulic circuit 68 for suppressing cavitation formed therein. Reference numerals L1 and L2 exemplify a pressure oil supply line and a return line in the case of illustration, and respectively communicate with the pressure oil supply chamber 65A and the return chamber 65B.

  Reference numeral 70 denotes a control valve unit, which is connected to a pressure oil supply source 78 such as a hydraulic pump. The control valve unit 70 is connected to the pressure oil input port IN and the return port OUT of the rear casing end 66B. Further, the control valve unit 70 is configured to return the oil to the tank T via the return line 72 and the check valve 74. The makeup port MP is connected to the upstream side of the check valve 74 in the return line 72 via a line 76.

  The pressure of the makeup port MP is set so as to give the function of suppressing the cavitation described above, and is usually about 0.3 MPa.

  FIG. 2 shows a schematic internal arrangement of the rear casing end 66B of FIG. 1. FIG. 2A shows a makeup port passage MPL perpendicular to the axial direction of the swash plate type piston motor 100. FIG. FIG. 4B is a sectional view taken along line ZZ in FIG.

As shown in (a) of FIG. 2, the relief valve RF1, RF2 opening of the passage 64 that is, as shown in (b) of FIG, are disposed symmetrically with respect to the axial center line of the output rotary shaft 50 Yes. On the upper side of the figure, check valves CH1 and CH2 are arranged. The bearing 50B and the needle bearing 56 described above constitute the first and second bearings in the present invention, respectively.

  In the swash plate type piston motor 100 configured as described above, since the pressure oil in the makeup port passage MPL is always supplied to the passage 64, the makeup port is provided to the needle bearing 56 by the throttle portion 64. Oil is supplied at an appropriate pressure lower than the pressure of MP.

  Although one example of the preferred embodiment of the present invention has been described above, the present invention is not limited to that illustrated in FIGS. 1 and 2, and various modifications can be made. For example, in the throttle portion 60A, the left end portion of the through-passage 64 is shown as a small-diameter hole in FIGS. 1 and 2; A member may be separately prepared and screwed to the screw portion. In that case, it is possible to easily adjust the pressure in the recess to an appropriate value by preparing various small-diameter holes in the throttle member.

It is a principal part axial sectional view of the swash plate type piston motor to which the present invention is applied. FIG. 1 shows a schematic arrangement configuration inside the end case of FIG. 1, wherein FIG. 1 (a) shows a cross-sectional view along the makeup port passage perpendicular to the axial direction of the swash plate type piston motor, and FIG. These are the ZZ sectional view taken on the line of (a). It is sectional drawing which shows the internal structure of the conventional swash plate type piston motor.

Explanation of symbols

50 output rotary shaft 50A oil seal 50B bearing 52 swash plate 54 piston 56 needle bearing 58 convex portion 60 concave portion 60A throttle portion 62 brake portion 64 through passage 65A pressure oil supply chamber 65B return chamber 66 front casing 66A rear casing 66B case end Portion 68 Hydraulic circuit 70 for suppressing cavitation Control valve unit 72 Return line 74 Check valve 76 Line 78 Pressure oil supply source 100 Swash plate type piston motor

Claims (3)

One end side is supported via a first bearing at the center portion of the front casing and the front casing, and a plurality of pistons are disposed in the circumferential direction in the other end side thicker portion, and the center portion Is provided with an output rotating shaft formed with a recess opening on the rear side, and a hydraulic circuit that forms a supply pressure oil chamber and a return chamber to the piston and suppresses cavitation while forming a projection that fits into the recess. A rear casing having a make-up port connected to the second casing, and a second bearing that supports the rear side of the output rotation shaft disposed between the outer peripheral surface of the convex portion and the inner peripheral surface of the concave portion. A swash plate type piston motor,
The swash plate type is characterized in that the convex portion is formed with a through passage that opens in the makeup port passage of the hydraulic circuit that communicates one side with the inside of the concave portion and communicates the other side to the makeup port. Piston motor.   The swash plate type piston motor according to claim 1, wherein a throttle is provided in the through passage. 3. The throttle according to claim 2, wherein the throttle is formed by screwing a throttle member having a hole having a diameter smaller than the inner diameter of the through-passage into a female screw portion formed at an end of the through-passage on the concave side. The described swash plate type piston motor.

Images