Hydraulic motor

Abstract

Reduce torque loss. [Solution] The hydraulic motor 1 comprises a casing 10, a drive shaft 20 rotatably supported by the casing 10, a brake disc 90 positioned on the outer circumference of the drive shaft 20 with relative rotation with respect to the drive shaft 20 restricted, a separate plate 91 positioned adjacent to the brake disc 90 and the drive shaft 20 in the axial direction with respect to the casing 10 restricted, a brake piston 92 movable in the axial direction of the drive shaft 20 and positioned alongside the brake disc 90 and the separate plate 91 in the axial direction, a brake spring 94 that biases the brake piston 92 so that it presses against the brake disc 90 and the separate plate 91, and a first oil chamber P1 that generates hydraulic pressure to bias the brake piston 92 in the same direction as the biasing direction of the brake spring 94 when oil is introduced.

Description

Technical Field

[0001] The present disclosure relates to a hydraulic motor.

Background Art

[0002] The brake device of a hydraulic motor is disposed in an accommodation space provided at a position on the outer peripheral region of the end portion of the drive shaft inside the casing (see, for example, Patent Document 1). The brake device includes a plurality of brake disks and a plurality of separator plates. The brake disks and the separator plates are alternately arranged along the axial direction such that the separator plates are located at both axial ends. The brake disk is slidable along the axis of the drive shaft, and the relative rotation with the drive shaft is restricted. The separator plate is slidable along the axis of the drive shaft, and the relative rotation with the casing is restricted.

[0003] A brake piston is disposed at a position facing the separator plate at one axial end of the brake disk and the separator plate, and a brake regulating plate is disposed at a position facing the separator plate at the other axial end. The brake piston is slidably arranged along the axis of the drive shaft. The brake piston is normally pressed toward the separator plate at one axial end by a brake spring interposed between the casing. When hydraulic pressure is applied to the brake piston, the brake piston moves in a direction away from the separator plate at one axial end against the pressing force of the brake spring. The brake regulating plate is interposed between the casing and the separator plate at the other axial end in the axial direction. The brake regulating plate restricts the movement of the brake disk and the separator plate when the brake piston is pressed toward the separator plate at one axial end in the axial direction, and applies a frictional force between the brake disk and the separator plate.

[0004] In the hydraulic motor configured as described above, removing the pressing force from the brake piston allows relative rotation of the brake disc and the separator plate. This enables rotation of the drive shaft relative to the casing. Conversely, when the brake disc and the separator plate are pressed against the brake restricting plate via the brake piston, a frictional force acts between them, restricting their relative rotation. This restricts the rotation of the drive shaft relative to the casing. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-227879 [Overview of the project] [Problems that the invention aims to solve]

[0006] Because the brake disc and drive shaft rotate in sync, torque loss occurs due to the agitation of the hydraulic pressure.

[0007] This disclosure aims to provide a hydraulic motor with reduced torque loss. [Means for solving the problem]

[0008] A hydraulic motor is provided comprising: a casing; a rotating shaft rotatably supported by the casing; a first member positioned on the outer circumference of the rotating shaft such that its relative rotation with the rotating shaft is restricted; a second member positioned adjacent to the first member in the axial direction of the rotating shaft such that its relative rotation with the casing is restricted; a third member movable in the axial direction of the rotating shaft and positioned alongside the first and second members in the axial direction; a spring that biases the third member such that it presses against the first and second members; and a first oil chamber that, when oil is introduced, generates hydraulic pressure that biases the third member in the same direction as the biasing direction of the spring. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a hydraulic motor with reduced torque loss. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional side view of a hydraulic motor according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional plan view of the hydraulic motor shown in Figure 1. [Figure 3] Figure 3 shows a brake disc applied to the hydraulic motor shown in Figure 1. [Figure 4] Figure 4 shows a separate plate applied to the hydraulic motor in Figure 1. [Figure 5] Figure 5 is a cross-sectional plan view of the auxiliary member, the first oil chamber, and the second oil chamber of the first embodiment. [Figure 6] Figure 6 is a cross-sectional plan view of the auxiliary member, the first oil chamber, and the second oil chamber of the first embodiment. [Figure 7] Figure 7 is a cross-sectional plan view of the auxiliary member, the first oil chamber, and the second oil chamber of the second embodiment. [Figure 8] Figure 8 is a cross-sectional plan view of the auxiliary member, the first oil chamber, and the second oil chamber of the third embodiment. [Modes for carrying out the invention]

[0011] The embodiments described below will be explained with reference to the drawings, but the disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0012] [First Embodiment] <Hydraulic motor> Figure 1 is a cross-sectional side view of a hydraulic motor according to the first embodiment. Figure 2 is a cross-sectional plan view of the hydraulic motor shown in Figure 1. The hydraulic motor 1 is an oblique-axis axial piston motor. The hydraulic motor 1 is a hydraulic motor for driving vehicles used as construction machinery such as bulldozers and hydraulic excavators. The hydraulic motor 1 includes a casing 10 that houses various components of the hydraulic motor 1.

[0013] The casing 10 comprises a casing body 11 and an end cover 12. The casing body 11 is cylindrical with one end in the axial direction open. The casing body 11 is hollow, having a hollow interior 11a. The hollow interior 11a is filled with oil. The hollow interior 11a comprises a storage space 11b, a storage space 11d, and a storage space 11e. Storage spaces 11b, 11d, and 11e are in communication with each other.

[0014] The housing space 11b accommodates a plurality of brake discs (first members) 90 and a plurality of separate plates (second members) 91, which will be described later. The housing space 11b is an annular hole located at a position that is the outer circumference of the disc portion 23 of the drive shaft 20, which will be described later. The housing space 11b is located adjacent to the roller housing portion 42b of the second tapered roller bearing 42, which will be described later.

[0015] The housing space 11d houses the first tapered roller bearing 41, which will be described later.

[0016] The housing space 11e houses the second tapered roller bearing 42, which will be described later.

[0017] On the inner peripheral surface of the casing main body portion 11 facing the accommodation space 11b, a plurality of arc-shaped groove portions (not shown) are arranged. The arc-shaped groove portions are recesses for engaging with the arc-shaped protrusions 91a of a separate plate 91 described later. The arc-shaped groove portions open toward the accommodation space 11b and are arranged at equal intervals from each other.

[0018] As shown in FIG. 2, a pair of connection passages 11f communicating between the accommodation space 11b, the accommodation space 11d, and the accommodation space 11e are arranged. In the embodiment, the pair of connection passages 11f are arranged at positions shifted from each other by 180°.

[0019] The end cover 12 closes the opening of the casing main body portion 11. The end cover 12 is arranged at one end in the axial direction of the casing main body portion 11.

[0020] In the casing 10, a drive shaft (rotating shaft) 20 and a cylinder block 30 are accommodated in the hollow interior 11a of the casing main body portion 11.

[0021] The drive shaft 20 includes a first bearing support portion 21, a second bearing support portion 22, and a disk portion 23. The first bearing support portion 21, the second bearing support portion 22, and the disk portion 23 are integrally formed. The first bearing support portion 21 is cylindrical. The second bearing support portion 22 is arranged at one end in the axial direction of the first bearing support portion 21. The second bearing support portion 22 is cylindrical with a larger diameter than the first bearing support portion 21. The disk portion 23 is arranged at one end in the axial direction of the second bearing support portion 22. The disk portion 23 is a disk shape with a larger diameter than the second bearing support portion 22.

[0022] The drive shaft 20 is rotatably supported around its axis 20C relative to the casing body 11 of the casing 10 via a first bearing support portion 21 and a second bearing support portion 22. A first tapered roller bearing 41 is positioned between the first bearing support portion 21 and the casing body 11. A second tapered roller bearing 42 is positioned between the second bearing support portion 22 and the casing body 11. The second tapered roller bearing 42 has a larger diameter than the first tapered roller bearing 41. The second tapered roller bearing 42 is interposed between the drive shaft 20 and the casing body 11 with the larger diameter portion of the tapered roller 42a facing one end of the casing body 11 in the axial direction.

[0023] The disc portion 23 slidably supports multiple piston rods 40 and a center shaft 50. Multiple rod support portions 23a and shaft support portions 23b are arranged on one axial end face of the disc portion 23. The rod support portions 23a and shaft support portions 23b are each substantially hemispherical recesses formed on one axial end face of the disc portion 23. The rod support portions 23a support the piston rods 40. In an axial view, the rod support portions 23a are arranged at equal intervals from each other on a common circumference centered on the axis 20C of the drive shaft 20. The shaft support portions 23b support the center shaft 50. The shaft support portions 23b are located on the axis 20C of the drive shaft 20 in the disc portion 23. A relief passage 24 is connected to the shaft support portions 23b.

[0024] The relief passage 24 is a passage for releasing oil from the oil passage located in the inner shaft 51, which will be described later. The relief passage 24 extends from the shaft support portion 23b along the axis 20C of the drive shaft 20 to the other axial direction, and then extends radially outward as it proceeds toward the other axial direction. The relief passage 24 opens onto the outer circumferential surface of the drive shaft 20 between the first bearing support portion 21 and the second bearing support portion 22.

[0025] A spline 25 is arranged on the outer circumferential surface of the disc portion 23 that faces the housing space 11b. The spline 25 engages with the spline groove 90a of the brake disc 90, which will be described later. The spline 25 is formed on the outer circumferential surface of the disc portion 23 at a position opposite to the portion of the casing 10 that forms the arc-shaped groove.

[0026] The piston rod 40 is tapered, with its outer diameter increasing from the base to the tip. The base of the piston rod 40 is one side in the axial direction, and the tip is the other side. The piston rod 40 comprises a support ball head 40a located at the base and a piston portion 40b located at the tip. The support ball head 40a is spherical. The support ball head 40a is slidably inserted into the rod support portion 23a of the disc portion 23 of the drive shaft 20. The support ball head 40a has a larger outer diameter than the piston portion 40b.

[0027] The center shaft 50 comprises an inner shaft 51 and an outer race 52. The inner shaft 51 comprises a shaft base 51a and a shaft support ball head 51b. The shaft base 51a is cylindrical. The shaft support ball head 51b is located at the base end of the shaft base 51a. The base end of the shaft support ball head 51b is one side in the axial direction of the shaft support ball head 51b. The shaft support ball head 51b is spherical. The shaft support ball head 51b is slidably inserted into a shaft support portion 23b formed on the disc portion 23 of the drive shaft 20. The outer diameter of the shaft base 51a is smaller than the outer diameter of the shaft support ball head 51b. Inside the inner shaft 51, an oil passage is located between one end face in the axial direction of the shaft base 51a and the top of the shaft support ball head 51b.

[0028] The outer race 52 is cylindrical. The outer race 52 has a shaft housing hole 52a and a spring housing hole 52b on its axis 30C. The shaft housing hole 52a is a cylindrical hole that opens to the other axial end face of the outer race 52. The shaft housing hole 52a has a circular cross-section along its radial direction. The inner diameter of the shaft housing hole 52a is such that the shaft base 51a of the inner shaft 51 can be fitted in without any looseness. The spring housing hole 52b is a cylindrical hole that opens to the other axial end face of the outer race 52. The spring housing hole 52b has a circular cross-section along its radial direction. The spring housing hole 52b houses a compression spring 53 inside.

[0029] The compression spring 53 is a coil spring. The outer diameter of the compression spring 53 is slightly smaller than the inner diameter of the spring housing hole 52b. The natural length of the compression spring 53 is longer than the spring housing hole 52b.

[0030] After attaching the support ball heads 40a of the multiple piston rods 40 and the shaft support ball heads 51b of the center shaft 50, which are configured in this way, to the rod support parts 23a and shaft support parts 23b formed on the disc part 23 of the drive shaft 20, the retainer plate 60 is fixed to the end face of the disc part 23. As a result, the multiple piston rods 40 and the center shaft 50 are supported so as to be able to tilt relative to the end face of the disc part 23, while restricting the separation movement of each support ball head 40a and shaft support ball head 51b from the end face of the disc part 23.

[0031] The retainer plate 60 slidably holds a plurality of piston rods 40 and a center shaft 50 supported by the disc portion 23. The retainer plate 60 is a plate-shaped member. The retainer plate 60 includes a rod insertion hole 61a and a shaft insertion hole 61b. The rod insertion hole 61a is located in the retainer plate 60 at a position opposite to the rod support portion 23a of the disc portion 23. The shaft insertion hole 61b is located at a position opposite to the shaft support portion 23b. The rod insertion hole 61a is a hole having an inner diameter smaller than the outer diameter of the support ball head 40a of the piston rod 40. The shaft insertion hole 61b is a hole having an inner diameter smaller than the outer diameter of the shaft support ball head 51b of the center shaft 50. The retainer plate 60 is attached to one axial end face of the disc portion 23 with the piston rods 40 already inserted through the rod insertion holes 61a and the center shaft 50 inserted through the shaft insertion hole 61b.

[0032] The cylinder block 30 houses the piston portions 40b of multiple piston rods 40 so that they can reciprocate along the axis 30C, and the center shaft 50 is mounted without play. The cylinder block 30 is a columnar member with a circular cross-section along the radial direction. The cylinder block 30 comprises multiple cylinder bores 31 and shaft mounting holes 32. The cylinder bores 31 and shaft mounting holes 32 are cylindrical holes formed along the axis 30C of the cylinder block 30. The cylinder bores 31 and shaft mounting holes 32 have a uniform circular cross-section along the radial direction. The cylinder bores 31 and shaft mounting holes 32 open to the other axial end face of the cylinder block 30.

[0033] Multiple cylinder bores 31 are arranged at equal intervals from each other on a common circumference centered on the axis 30C of the cylinder block 30. The circumference on which the cylinder bores 31 are arranged is the same dimension as the circumference on which the rod support portion 23a is located in the disc portion 23 of the drive shaft 20. The piston portion 40b of the piston rod 40 is housed in each cylinder bore 31 so as to be able to reciprocate along the axis 30C.

[0034] The shaft mounting hole 32 is located on the axis 30C of the cylinder block 30. The outer race 52 of the center shaft 50 is fitted into this shaft mounting hole 32 without any play. Since the outer race 52 has a longer axial length than the shaft mounting hole 32, a portion of it protrudes outward from one axial end face of the cylinder block 30.

[0035] The cylinder block 30 has an axial end face, through which the shaft mounting hole 32 and cylinder bore 31 are opened, that is a plane perpendicular to the axis 30C, while the other end face is a concave surface 30a. The concave surface 30a of the cylinder block 30 is spherical in shape, with its center on the extension of the axis 30C of the cylinder block 30. A communication hole 33 and a plurality of connecting passages 34 are opened in the concave surface 30a of the cylinder block 30.

[0036] The communication hole 33 is a cylindrical hole. The communication hole 33 is located on the axis 30C of the cylinder block 30. The communication hole 33 communicates with the shaft mounting hole 32. The inner diameter of the communication hole 33 is smaller than the inner diameter of the shaft mounting hole 32.

[0037] The connecting passages 34 are openings arranged on the circumference of the cylinder block 30 centered on the axis 30C, and are positioned at equal intervals from one another. The circumference on which the connecting passages 34 are located has a smaller radius than the circumference on which the cylinder bores 31 are located. The connecting passages 34 have a smaller inner diameter than the cylinder bores 31. Each connecting passage 34 communicates with an individual cylinder bore 31.

[0038] The cylinder block 30 and the drive shaft 20 are connected by multiple piston rods 40 and a center shaft 50 so that they can slide against each other with their axes intersecting. The cylinder block 30 is capable of rotating around the axis of the center shaft 50, that is, around its own axis 30C.

[0039] A valve plate 70 is positioned between the concave surface 30a of the cylinder block 30 and the end cover 12 of the casing 10. The valve plate 70 comprises a sliding spherical protrusion 71 and a sliding cylindrical protrusion 72. The valve plate 70 slidably contacts the concave surface 30a of the cylinder block 30 via the sliding spherical protrusion 71, and slidably contacts the guide surface 12a of the end cover 12 via the sliding cylindrical protrusion 72. The sliding spherical protrusion 71 protrudes spherically with the same radius of curvature as the concave surface 30a of the cylinder block 30. The sliding spherical protrusion 71 is slidable in close contact with the entire surface of the concave surface 30a of the cylinder block 30. The sliding cylindrical protrusion 72 is a convex cylindrical surface that protrudes toward the opposite side from the sliding spherical protrusion 71.

[0040] The guide surface 12a of the end cover 12, which contacts the sliding projection cylindrical surface 72, has the same radius of curvature as the sliding projection cylindrical surface 72. The guide surface 12a of the end cover 12 is a concave cylindrical surface with a longer arc length than the sliding projection cylindrical surface 72. The guide surface 12a of the end cover 12 is positioned opposite the disc portion 23 of the drive shaft 20. The position of the guide surface 12a of the end cover 12 is set such that the center point X of the shaft support portion 23b located on the disc portion 23 of the drive shaft 20 is included, and the line perpendicular to the axis 20C of the drive shaft 20 becomes the central axis of the cylinder.

[0041] The valve plate 70 is moved along the guide surface 12a of the end cover 12 by the actuator 80. The actuator 80 has an actuator piston 81, which is an output element, that is tiltably engaged with the valve plate 70 via a linkage pin 82.

[0042] High-pressure ports and low-pressure ports (not shown) are opened on the sliding spherical surface 71 of the valve plate 70 at positions corresponding to the communication passage 34 of the cylinder block 30. The high-pressure ports and low-pressure ports are arranged such that, for example, if the cylinder block 30 is divided into two halves by a virtual plane including the axis 30C of the cylinder block 30 and the axis 20C of the drive shaft 20, the high-pressure ports communicate with a plurality of cylinder bores 31 located on one side, and the low-pressure ports communicate with a plurality of cylinder bores 31 located on the other side.

[0043] A connecting passage 73 is positioned between the sliding spherical surface 71 and the sliding cylindrical surface 72 of the valve plate 70. The connecting passage 73 opens to the sliding spherical surface 71 at a position opposite the axis 30C of the cylinder block 30.

[0044] <Brake system> The hydraulic motor 1 is equipped with a brake device 9 that restricts the rotation of the drive shaft 20. The brake device 9 comprises a brake disc 90 and a separate plate 91, a brake piston (third member) 92, a second oil chamber P2, a brake restricting plate 93, a brake spring (spring) 94, an auxiliary member (fourth member) 97, and a first oil chamber P1.

[0045] Figure 3 shows a brake disc applied to the hydraulic motor of Figure 1. The brake disc 90 is positioned on the outer circumference of the drive shaft 20, with its relative rotation to the drive shaft 20 restricted. The brake disc 90 is fixed in the circumferential direction to the drive shaft 20 by a spline connection. The brake disc 90 is interposed between the drive shaft 20 and the brake piston 92, suppressing the rotation of the drive shaft 20 by friction. The brake disc 90 is an annular flat plate. The brake disc 90 has an outer diameter smaller than the inner circumferential surface of the casing 10. The brake disc 90 is slidably positioned along the axis 20C of the drive shaft 20. The brake disc 90 has a spline groove 90a on its inner circumference.

[0046] As shown in Figures 1 and 2, the brake disc 90 housed in the housing space 11b engages with the splines 25 of the drive shaft 20 via spline grooves 90a formed on its inner circumference. This allows the brake disc 90 to slide along its axis 20C relative to the drive shaft 20, while restricting its relative rotation with respect to the drive shaft 20.

[0047] The diameter of the brake disc 90 is set according to the required braking capacity. In conventional technology, the braking capacity can only be adjusted in one stage, so a brake disc 90 with a diameter that matches the braking capacity required in emergencies was necessary. In this embodiment, as will be described later, the braking capacity is set in two stages: a first braking state used when the vehicle is normally stopped, and a second braking state that is greater than the first braking state and used in emergencies. Therefore, the diameter of the brake disc 90 can be set to a smaller diameter compared to conventional technology.

[0048] Figure 4 shows a separate plate applied to the hydraulic motor of Figure 1. The separate plate 91 is an annular flat plate. The separate plate 91 has an inner diameter larger than the splines 25 of the disc portion 23. The separate plate 91 has a plurality of arc-shaped protrusions 91a on its outer circumference.

[0049] The separate plate 91 is positioned adjacent to the brake disc 90 and the drive shaft 20 in the axial direction, with its relative rotation to the casing 10 restricted. The separate plate 91 engages with the arc-shaped groove of the casing 10 via an arc-shaped projection 91a formed on its outer circumference. As a result, the separate plate 91 is slidable along the axis 20C of the drive shaft 20 relative to the casing 10, while its relative rotation to the casing 10 is restricted.

[0050] The brake discs 90 and the separate plates 91 are arranged alternately along the axis 20C of the drive shaft 20, such that the separate plates 91 are at both ends in the axial direction.

[0051] The brake piston 92 and brake regulating plate 93 are positioned opposite each other, with the brake disc 90 and the separate plate 91 in between. In other words, the brake disc 90 and the separate plate 91 are sandwiched from both ends by the brake piston 92 and the brake regulating plate 93.

[0052] As shown in Figures 1 and 2, the brake piston 92 is a cylindrical body arranged on the inner surface of the casing body 11 so as to surround the outer circumference of the cylinder block 30. The brake piston 92 is movable in the axial direction of the drive shaft 20 and is arranged alongside the brake disc 90 and the separate plate 91 in the axial direction. The brake piston 92 presses the brake disc 90 and the separate plate 91 in the axial direction of the drive shaft 20, bringing them into contact. The brake piston 92 is slidable along the axis 20C of the drive shaft 20 relative to the casing body 11. The brake piston 92 has a second oil chamber P2 and a first oil chamber P1, which will be described later, between it and the casing 10. The brake piston 92 has a pressing portion 92a at its other axial end and a pair of brake spring chambers 92b at its other end. The brake piston 92 has a pressure-receiving surface (for example, 92d, described later) that faces the first oil chamber P1.

[0053] The second oil chamber P2 is located between the brake piston 92 and the casing 10. When oil is introduced into the second oil chamber P2, it generates hydraulic pressure that biases the brake piston 92 in the opposite direction to the biasing direction of the brake spring 94. The hydraulic pressure of the second oil chamber P2 allows the brake piston 92 to slide away from the brake disc 90. In this embodiment, the hydraulic pressure of the second oil chamber P2 allows the brake piston 92 to slide away from the separator plate 91 at one end in the axial direction. The second oil chamber P2 is located between a movable pressure-receiving surface 92c of the brake piston 92, which is aligned in a direction perpendicular to the axis 20C of the drive shaft 20, and a fixed pressure-receiving surface 11g of the casing 10, which is positioned opposite the movable pressure-receiving surface 92c of the brake piston 92. The second oil chamber P2 is an annular space. The second oil chamber P2 is connected to the first hydraulic power supply source Q1 (see Figure 6) by a refueling passage (oil channel) 11h (see Figure 6). The refueling passage 11h supplies oil to the second oil chamber P2.

[0054] The pressing portion 92a is a protruding portion configured to face the portion of the separate plate 91, which is located in the housing space 11b, that overlaps with the brake disc 90. The pressing portion 92a can contact the separate plate 91 without contacting the spline 25 of the drive shaft 20 or the casing 10.

[0055] The brake spring chamber 92b is a cylindrical hole formed along the axis 20C of the drive shaft 20. Each brake spring chamber 92b houses a brake spring 94 inside.

[0056] The brake spring 94 biases the brake piston 92. The brake spring 94 biases the brake piston 92 in a direction that presses it against the brake disc 90. In this embodiment, the brake spring 94 biases the brake piston 92 in a direction that presses it against the separate plate 91 at one end in the axial direction. The brake spring 94 is a coil spring interposed between it and the end cover 12. The brake spring 94 is located inside the brake spring chamber 92b in a compressed state. The brake spring 94 functions to maintain a state in which the movable pressure receiving surface 92c and the fixed pressure receiving surface 11g are always in close proximity in the second oil chamber P2.

[0057] The brake restricting plate 93 is a component that restricts the movement of the brake disc 90 and the separate plate 91 toward the second tapered roller bearing 42. The brake restricting plate 93 is an annular thick plate. The brake restricting plate 93 is positioned in the housing space 11b opposite the roller housing portion 42b of the second tapered roller bearing 42. The surface of the brake restricting plate 93 that faces the second tapered roller bearing 42 abuts against the stepped portion 11m formed in the casing body portion 11. The surface of the brake restricting plate 93 that faces the housing space 11b faces the portion of the separate plate 91 that overlaps with the brake disc 90. When the movable pressure-receiving surface 92c of the brake piston 92 and the fixed pressure-receiving surface 11g of the casing 10 are in close proximity, the brake regulating plate 93 maintains a state in which the brake disc 90 and the separate plate 91 are pressed against each other by the pressing force of the brake spring 94 between it and the pressing portion 92a of the brake piston 92.

[0058] Figure 5 is a cross-sectional plan view of the auxiliary member, first oil chamber, and second oil chamber of the first embodiment. Figure 6 is a cross-sectional plan view of the auxiliary member, first oil chamber, and second oil chamber of the first embodiment. The auxiliary member 97 is interposed between the brake piston 92 and the casing 10. The auxiliary member 97 seals the first oil chamber P1. The auxiliary member 97 seals the space between the brake piston 92 and the casing 10. The auxiliary member 97 is fixed to the casing body portion 11 of the casing 10. The auxiliary member 97 does not slide along the axis 20C of the drive shaft 20. The auxiliary member 97 is a cylindrical body positioned on the outer circumference of the axial end of the brake piston 92. The auxiliary member 97 is a cylindrical body positioned on the inner surface of the casing body portion 11 so as to surround the outer circumference of one axial end of the brake piston 92. The auxiliary member 97 has a pressing portion 97a positioned at its other axial end. In the auxiliary member 97, the first oil chamber P1 is positioned between the casing 10 and the pressing portion 97a.

[0059] The first oil chamber P1 is located on the outer circumference of the auxiliary member 97. When oil is introduced into the first oil chamber P1, it generates hydraulic pressure that biases the brake piston 92 in the same direction as the biasing direction of the brake spring 94. The hydraulic pressure of the first oil chamber P1 presses the brake disc 90 in a direction that clamps the brake disc 90 between the drive shaft 20 and the brake piston 92. In this embodiment, the first oil chamber P1 is an annular space. The first oil chamber P1 is located between the pressure-receiving surface (e.g., 92d) of the brake piston 92 and the auxiliary member 97. In this embodiment, the first oil chamber P1 is located between a fixed pressure-receiving surface 97c in the auxiliary member 97 that is aligned perpendicular to the axis 20C of the drive shaft 20 and a movable pressure-receiving surface 92d in the brake piston 92 that is positioned opposite the auxiliary member 97. In this embodiment, the hydraulic pressure of the first oil chamber P1 makes the brake piston 92 slidable in a direction that clamps the brake disc 90 and the separate plate 91. The first oil chamber P1 is connected to a refueling passage (oil channel) 11i that connects it to the second hydraulic power supply source Q2. The refueling passage 11i supplies oil to the first oil chamber P1.

[0060] <effect> As shown in Figures 1 and 2, when oil is not supplied from the first hydraulic supply source Q1 and the second hydraulic supply source Q2, and no hydraulic pressure is acting on the second oil chamber P2 and the first oil chamber P1, the pressing force of the brake spring 94 maintains a state in close proximity between the movable pressure receiving surface 92c and the fixed pressure receiving surface 11g. This maintains a state in which the brake disc 90 and the separate plate 91 are pressed against each other between the pressing portion 92a of the brake piston 92 and the brake regulating plate 93. In this way, the rotation of the drive shaft 20 relative to the casing 10 is restricted. This state is called the first brake operating state.

[0061] When oil is supplied from the first hydraulic supply source Q1 from the first brake operating state and hydraulic pressure is applied to the second oil chamber P2, the gap between the movable pressure receiving surface 92c and the fixed pressure receiving surface 11g expands against the pressing force of the brake spring 94, and the pressing force between the brake disc 90 and the separate plate 91 is removed. As a result, the brake disc 90 and the separate plate 91 become rotatable relative to each other, in other words, the drive shaft 20 becomes rotatable relative to the casing 10. This state is called the brake release state.

[0062] When the brake is released, oil is supplied to the high-pressure port and the low-pressure port is connected to the oil tank. As a result, the piston rod 40 in the cylinder bore 31 connected to the high-pressure port moves sequentially toward the drive shaft 20, and the piston rod 40 in the cylinder bore 31 connected to the low-pressure port moves sequentially backward, causing the cylinder block 30 to rotate and function as a hydraulic motor 1 with the drive shaft 20 as the output shaft. When the actuator 80 is driven to change the position of the valve plate 70 relative to the guide surface 12a of the end cover 12, the tilt angle of the cylinder block 30 relative to the drive shaft 20 changes, and the amount of stroke of the piston rod 40 relative to the cylinder bore 31, i.e., the capacity, is changed and the device operates in that state.

[0063] When oil is not supplied from the first hydraulic supply source Q1, no hydraulic pressure is acting on the second oil chamber P2, and oil is supplied from the second hydraulic supply source Q2, acting on the first oil chamber P1, in addition to the pressing force of the brake spring 94, the pressing force of the brake piston 92 due to the hydraulic pressure in the first oil chamber P1 acts. Specifically, the hydraulic pressure between the fixed pressure receiving surface 97c and the movable pressure receiving surface 92d causes the fixed pressure receiving surface 97c and the movable pressure receiving surface 92d to separate, and the movable pressure receiving surface 92c and the fixed pressure receiving surface 11g come into close proximity with a stronger pressing force than in the first brake operating state. As a result, the brake disc 90 and the separate plate 91 are pressed more strongly against each other between the pressing portion 92a of the brake piston 92 and the brake regulating plate 93 than in the first brake operating state. The rotation of the drive shaft 20 relative to the casing 10 is restricted with a stronger pressing force than in the first brake operating state. This state is called the second brake operating state.

[0064] When the second brake is activated, and oil is supplied from the first hydraulic supply source Q1 while the oil supply from the second hydraulic supply source Q2 is stopped, hydraulic pressure acts on the second oil chamber P2, and the hydraulic pressure in the first oil chamber P1 is removed, eliminating the pressing force acting between the fixed pressure receiving surface 97c and the movable pressure receiving surface 92d. As a result, the state in which the brake disc 90 and the separate plate 91 are pressed against each other between the pressing portion 92a of the brake piston 92 and the brake restricting plate 93 is eliminated. The restriction on the rotation of the drive shaft 20 relative to the casing 10 is released. In this way, the brake is released.

[0065] <Effects> As described above, in this embodiment, the brake spring 94 biases the brake piston 92 in a direction that presses it against the brake disc 90, thereby enabling a first brake operating state. In this embodiment, in addition to the pressing force of the brake spring 94, the hydraulic pressure of the first oil chamber P1 presses the brake disc 90 more strongly than in the first brake operating state, in a direction that clamps the brake disc 90 between the drive shaft 20 and the brake piston 92, thereby enabling a second brake operating state. More specifically, in this embodiment, in addition to the pressing force of the brake spring 94, the hydraulic pressure of the first oil chamber P1 allows the brake piston 92 to slide in a direction that clamps the brake disc 90 and the separate plate 91. According to this embodiment, a first brake operating state and a second brake operating state can be generated. According to this embodiment, the first brake operating state and the second brake operating state can be used interchangeably.

[0066] According to this embodiment, the brake capacity is set to two stages: a first brake operating state and a second brake operating state which is greater than the first brake operating state. According to this embodiment, the diameter of the brake disc 90 can be set to a smaller diameter compared to the conventional technology. According to this embodiment, torque loss in the brake disc 90 can be reduced. According to this embodiment, the fuel efficiency of the hydraulic motor 1 can be improved.

[0067] In contrast, conventional technology only allows for one-step adjustment of brake capacity. Therefore, it was necessary to adjust the brake capacity to match the required braking capacity in emergencies. This resulted in brake discs with a larger braking capacity than normal, leading to excessive torque loss.

[0068] The embodiment reduces torque loss and internal heat generation of the hydraulic motor 1. As a result, in the embodiment, it is not necessary to separately introduce cooling fluid for cooling purposes. In the embodiment, by suppressing the flow rate of the hydraulic fluid, the internal pressure of the hydraulic motor case is suppressed, and the cooling mechanism can be made smaller.

[0069] In this embodiment, the cooling flow rate inside the hydraulic motor 1 can be reduced, thereby reducing the rise in internal pressure of the casing 10.

[0070] [Second Embodiment] Figure 7 is a cross-sectional plan view of the auxiliary member, the first oil chamber, and the second oil chamber of the second embodiment. The hydraulic motor 1 illustrated here is, like in the first embodiment, mounted as a hydraulic motor for driving a vehicle used as construction machinery such as a bulldozer or hydraulic excavator. The second embodiment differs from the first embodiment in the auxiliary member (fourth member) 98 and the first oil chamber P1. In the second embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and their detailed descriptions are omitted. The same applies to the following embodiments.

[0071] The auxiliary member 98 is positioned between the brake piston 92 and the casing 10 in the axial direction of the drive shaft 20. The auxiliary member 98 receives hydraulic pressure from the first oil chamber P1 and biases the brake piston 92 in the pressing direction. The auxiliary member 98 is a columnar body positioned at the axial end of the brake piston 92. The auxiliary member 98 is inserted through the brake spring 94. The auxiliary member 98 has a cylindrical body inserted through the brake spring 94 and a head with a larger diameter than the outer diameter of the brake spring 94. The auxiliary member 98 is slidably positioned in the casing 10 along the axis 20C of the drive shaft 20 with its head protruding from the brake spring 94. The auxiliary member 98 has a pressing portion 98a at its other axial end. The first oil chamber P1 is positioned between the end cover 12 of the casing 10 and the head of the auxiliary member 98.

[0072] The first oil chamber P1 is located between the auxiliary member 98 and the casing 10 in the axial direction of the drive shaft 20. The first oil chamber P1 applies hydraulic pressure to the brake piston 92 so that the brake piston 92 is biased in the same direction as the brake spring 94. The first oil chamber P1 is located in the outer peripheral area of ​​the axial end of the auxiliary member 98. In the embodiment, the first oil chamber P1 is located between the outer peripheral portion of the auxiliary member 98 and the end cover 12 of the casing 10. In the embodiment, the first oil chamber P1 is an annular space provided around the auxiliary member 98. In the embodiment, the first oil chamber P1 presses the auxiliary member 98 with hydraulic pressure, making the brake piston 92 slidable in the direction of clamping the brake disc 90 and the separate plate 91. The first oil chamber P1 is connected to a second hydraulic pressure source Q2 by an oil supply passage (oil channel). The oil channel supplies oil to the first oil chamber P1.

[0073] <effect> The first brake activation state and the brake release state operate in the same manner as in the first embodiment.

[0074] When oil is not supplied from the first hydraulic supply source Q1, no hydraulic pressure is acting on the second oil chamber P2, and oil is supplied from the second hydraulic supply source Q2, acting on the first oil chamber P1, the hydraulic pressure in the first oil chamber P1 presses the auxiliary member 98, causing the pressing portion 98a to contact and press against the movable pressure-receiving surface 92e of the brake piston 92. As a result, the brake disc 90 and the separate plate 91 are pressed against each other more strongly than in the first brake operating state between the pressing portion 92a of the brake piston 92 and the brake regulating plate 93. The rotation of the drive shaft 20 relative to the casing 10 is restricted by a stronger pressing force than in the first brake operating state. This state is called the second brake operating state.

[0075] When oil is supplied from the first hydraulic supply source Q1 and the supply of oil from the second hydraulic supply source Q2 is stopped from the second brake operating state, hydraulic pressure acts on the second oil chamber P2, and the hydraulic pressure in the first oil chamber P1 is removed, eliminating the pressing force acting on the auxiliary member 98. As a result, the state in which the brake disc 90 and the separate plate 91 are pressed against each other between the pressing portion 92a of the brake piston 92 and the brake restricting plate 93 is eliminated. The restriction on the rotation of the drive shaft 20 relative to the casing 10 is released. In this way, the brake is released.

[0076] <Effects> As described above, in this embodiment, the hydraulic pressure of the first oil chamber P1 presses the auxiliary member 98, pressing the brake disc 90 more strongly than in the first brake operating state in the direction in which the drive shaft 20 and the brake piston 92 clamp the brake disc 90, thereby creating a second brake operating state. More specifically, in this embodiment, the hydraulic pressure of the first oil chamber P1 allows the brake piston 92 to slide via the auxiliary member 98 in the direction in which it clamps the brake disc 90 and the separate plate 91. According to this embodiment, a first brake operating state and a second brake operating state can be created. According to this embodiment, the first brake operating state and the second brake operating state can be used interchangeably.

[0077] [Third Embodiment] Figure 8 is a cross-sectional plan view of the auxiliary member, the first oil chamber, and the second oil chamber of the third embodiment. The third embodiment differs from the first embodiment in the auxiliary member (fourth member) 97, the auxiliary member (fourth member) 98, and the first oil chamber P1.

[0078] The auxiliary member 97 is positioned between the brake piston 92 and the casing 10 in the axial direction of the drive shaft 20. The auxiliary member 97 is a second columnar body positioned at the axial end of the auxiliary member 98. The auxiliary member 97 is slidably positioned on the end cover 12 of the casing 10 along the axis 20C of the drive shaft 20. The auxiliary member 97 has a pressing portion 97a at its other axial end. The auxiliary member 97 has a first oil chamber P1 positioned between it and the end cover 12 of the casing 10. The auxiliary member receives hydraulic pressure from the first oil chamber P1 and biases the brake piston 92 in the pressing direction.

[0079] The auxiliary member 98 is positioned between the brake piston 92 and the casing 10 in the axial direction of the drive shaft 20. The auxiliary member 98 is a first columnar body positioned at the axial end of the brake piston 92. The auxiliary member 98 is inserted through the brake spring 94. The auxiliary member 98 has a cylindrical body 98b inserted through the brake spring 94 and a head 98a with a larger diameter than the outer diameter of the brake spring 94. The head 98a protrudes from the brake spring 94 and is in contact with the movable pressure receiving surface 92e of the brake piston 92. The auxiliary member 98 is pressed in the axial direction by an auxiliary member 97 that receives hydraulic pressure from the first oil chamber P1, and the pressed auxiliary member 98 biases the brake piston 92.

[0080] The first oil chamber P1 is located between the auxiliary member 97 and the casing 10 in the axial direction of the drive shaft 20. The first oil chamber P1 is located in the outer peripheral area of ​​the axial end of the auxiliary member 97. In the embodiment, the first oil chamber P1 is located between the outer peripheral portion of the auxiliary member 97 and the end cover 12 of the casing 10. In the embodiment, the first oil chamber P1 is an annular space provided around the auxiliary member 97. In the embodiment, the first oil chamber P1 presses the auxiliary member 97 by hydraulic pressure, allowing the brake piston 92 to slide via the auxiliary member 98 in a direction that clamps the brake disc 90 and the separate plate 91. The first oil chamber P1 is connected to a second hydraulic supply source Q2 by an oil supply passage (oil passage). The oil passage supplies oil to the first oil chamber P1.

[0081] <effect> The first brake activation state and the brake release state operate in the same manner as in the first embodiment.

[0082] When oil is not supplied from the first hydraulic supply source Q1, no hydraulic pressure is acting on the second oil chamber P2, and oil is supplied from the second hydraulic supply source Q2, acting on the first oil chamber P1, the hydraulic pressure in the first oil chamber P1 presses the auxiliary member 97, causing the pressing portion 97a to contact the main body 98b of the auxiliary member 98. The auxiliary member 98 is pressed by the auxiliary member 97, causing the pressing portion 98a to contact and press against the movable pressure-receiving surface 92e of the brake piston 92. As a result, the brake disc 90 and the separate plate 91 are pressed more strongly against each other between the pressing portion 92a of the brake piston 92 and the brake regulating plate 93 than in the first brake operating state. The rotation of the drive shaft 20 relative to the casing 10 is restricted by a stronger pressing force than in the first brake operating state. This state is called the second brake operating state.

[0083] When the second brake is activated, and oil is supplied from the first hydraulic supply source Q1 while the oil supply from the second hydraulic supply source Q2 is stopped, hydraulic pressure acts on the second oil chamber P2, and the hydraulic pressure in the first oil chamber P1 is removed, eliminating the pressing force acting on the auxiliary member 97. As a result, the pressing force acting on the auxiliary member 98 is released, and the state in which the brake disc 90 and the separate plate 91 are pressed against each other between the pressing portion 92a of the brake piston 92 and the brake restricting plate 93 is eliminated. The restriction on the rotation of the drive shaft 20 relative to the casing 10 is released. In this way, the brake is released.

[0084] <Effects> As described above, in this embodiment, the hydraulic pressure of the first oil chamber P1 presses the auxiliary member 97, and through the auxiliary member 98, the brake disc 90 is pressed more strongly than in the first brake operating state in the direction in which it is clamped by the drive shaft 20 and the brake piston 92, thereby creating a second brake operating state. More specifically, in this embodiment, the hydraulic pressure of the first oil chamber P1 makes the brake piston 92 slidable through the auxiliary members 97 and 98 in the direction in which it clamps the brake disc 90 and the separate plate 91. According to this embodiment, a first brake operating state and a second brake operating state can be created. According to this embodiment, the first brake operating state and the second brake operating state can be used interchangeably. [Explanation of Symbols]

[0085] 1...Hydraulic motor, 9...Brake device, 10...Casing, 11...Casing body, 11b...Housing space, 11d...Housing space, 11e...Housing space, 11h...Oil supply passage (oil channel), 11i...Oil supply passage (oil channel), 12...End cover, 20...Drive shaft (rotating shaft), 20C...Axis center, 30...Cylinder block, 30C...Axis center, 40...Piston rod, 42...Second tapered roller bearing, 42a...Tapered roller, 42b...Roller housing, 50...Center shaft, 90...Brake disc (first component), 91...Separate plate (second component), 92...Brake piston (third component), 93...Brake regulating plate, 94...Brake spring (spring), 97...Auxiliary component (fourth component), P1...First oil chamber, P2...Second oil chamber.

Claims

1. Casing and, A rotating shaft rotatably supported in the casing, With relative rotation with respect to the aforementioned rotating shaft restricted, a first member is positioned in the outer peripheral region of the rotating shaft, With relative rotation with respect to the casing restricted, the first member and the second member are positioned adjacent to each other in the axial direction of the rotation shaft, A third member is movable in the axial direction of the rotation shaft and is arranged alongside the first member and the second member in the axial direction, A spring biases the third member so that it presses against the first and second members, A first oil chamber generates hydraulic pressure that biases the third member in the same direction as the biasing direction of the spring when oil is introduced, A hydraulic motor equipped with a hydraulic motor.

2. A second oil chamber generates hydraulic pressure that biases the third member in the opposite direction to the biasing direction of the spring when oil is introduced. Equipped with The hydraulic motor according to claim 1.

3. An auxiliary member interposed between the third member and the casing, Equipped with, The third member has a pressure-receiving surface facing the first oil chamber, The first oil chamber is located between the pressure-receiving surface of the third member and the auxiliary member, The hydraulic motor according to claim 1.

4. The auxiliary member seals the space between the third member and the casing. The hydraulic motor according to claim 3.

5. The rotational shaft has a fourth member positioned between the third member and the casing in the axial direction of the rotational shaft, The first oil chamber is located between the fourth member and the casing in the axial direction of the rotating shaft, The fourth member receives hydraulic pressure from the first oil chamber and biases the third member in the same direction. The hydraulic motor according to claim 1.

6. The fourth member is a columnar body inserted through the spring. The hydraulic motor according to claim 5.

7. The fourth member comprises a first columnar body inserted through the spring and a second columnar body arranged to be movable in the axial direction of the rotation axis relative to the casing. The first oil chamber is located between the second columnar body and the casing. The fourth member is configured such that the second columnar body, having received hydraulic pressure from the first oil chamber, presses the first columnar body in the axial direction, and the pressed first columnar body biases the third member. The hydraulic motor according to claim 5.

8. The casing has a second oil passage for supplying oil to the second oil chamber and a first oil passage for supplying oil to the first oil chamber. The hydraulic motor according to claim 2.

Images