JPS6040784A - Radial piston type hydraulic motor - Google Patents

Abstract

PURPOSE:To reduce the entire size by tapering the fitting portion between a distribution valve and rotor while assembling the brake system in the body of hydraulic motor. CONSTITUTION:A brake system 33 is arranged at the innercircumferential section of front casing 34 forming the body casing 1' together with the rear casing 1A and cam section 1C. Through function of spring 37, a push piston 35 is pushed to the left to contact tightly against the side of rotor 32 while a rotor 32 is also pushed to the left. Since the innercircumferential wall of a recess 32A of rotor 32 and the outercircumferential face of a distribution shaft 31 are tapered, pushing to the left of rotor 32 will cause pressure contact of the innercircumferential wall of recess 32A against the outercircumferential face of the distribution shaft 31. In order to release the brake system 33, fluid pressure is applied through a fluid path 39 into the pressure chamber 38. The push piston 35 will displace in the direction departing from the side of rotor 32 to release the pushing force of rotor 32 to the right.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radial piston type hydraulic motor used, for example, as a traveling hydraulic motor or a turning hydraulic motor for construction machinery.

2. Description of the Related Art Generally, construction machines such as hydraulic excavators and hydraulic cranes have a structure in which they are driven and rotated by hydraulic motors. A brake device is attached to the hydraulic motor to ensure that it stands still when not being driven and to prevent it from rotating excessively due to its own weight or the like.

FIG. 1 shows a hydraulic motor with a brake device according to the prior art.

In the figure, 1 includes a carrier casing IA, a front casing IB, and each of the casings IA.

The figure shows a main body casing consisting of a cam part IC provided between 18 parts, and a cam surface ID is formed on the inner circumferential wall of the cam part IC of the main body casing 1. Reference numeral 2 indicates a rotor housed inside the main body casing 1, and the rotor 2 is rotated eccentrically with respect to the cam surface ID. The rotor 2 has a plurality of cylinders 3, 3 .・
... are bored into each cylinder 3, and a piston 4 is inserted into each cylinder 3 so as to be able to reciprocate. A seam 5 is swingably connected to each piston 4, and the seam 5 is in sliding contact with the cam surface ID. Further, the rotor 2 has two cylindrical four parts opening toward the rear casing IA at its center of rotation, while an output shaft mounting part 2B extending in tandem with the front casing IB is formed on the other side of the rotor 2. 2 is integrally formed. A sealed bearing 6 is interposed between the front casing IB and the output shaft mounting portion 2B, and the rotor 2 is rotatably supported by the bearing 6 on the main body casing 1.

Next, reference numeral 7 indicates a distribution shaft, and the distribution shaft 7 is a cylindrical member integrally formed with the rear casing IA, and its tip end is fitted into the recess 2A of the rotor 2. The distribution shaft 7 has an opening on its circumferential surface, and when the rotor 2 rotates, the cylinder 3 is intermittently connected to the JJI ports 8 and 9 of each ship.
communicates with a suction passage 10.11 bored in the rear casing IA.

Further, reference numeral 12 denotes a brake device installed on the main body of the hydraulic motor configured as described above, and the brake device 12 is normally in a braking state and is released from braking by supplying fluid pressure. This is a so-called negative type brake. For this purpose, two M annular steps 1
A number member 1 formed of an annular member having 3A and 13B
3 is fixedly provided on the outer surface of the front casing IB, and a pushing piston 14 is fitted into the inner peripheral surface of the front casing IB so as to be slidable in the axial direction. The pushing piston 14
is formed in an annular shape so that the output shaft mounting portion 2B of the rotor 2 is inserted therethrough, and the -fl'ltl l! A spring 15 is interposed between the first surface and the outer 11111 surface of the front casing IB to bias the pushing piston 14 in a direction away from the front casing IB. Further, a swing plate 16 is interposed between the other side surface of the pushing piston 14 and the stepped portion 13B of the mounting member 13. The support plate 16 is formed of an annular plate, and its inner circular surface is spline-coupled to the outer peripheral surface of the output shaft mounting portion 2B by a spline portion 17. Under normal conditions, the friction plate 16 is held between the pushing piston 14 and the stepped portion 13B of the mounting member 13 by the action of the spring 15, so that the rotor 2 can be fixed in a non-rotating state. It has become.

Further, a pressure chamber 18 is formed between the pushing piston 14 and the stepped portion 13A of the mounting portion 13, and the pressure chamber 18 is bored in several sections 13, and one end is connected to a fluid pressure source. When the other end of the fluid passage 19 opened and pressure fluid was introduced into the pressure chamber 18 through the fluid passage 19, the pushing piston 14
is displaced in a direction away from the friction plate 16 against the force of the spring 15, so that the rotor 2 rotates and slides together with the friction plate 16.

In the figure, reference numeral 20 designates an oil passage that releases leaked oil from the suction/exhaust groove 8+9 into the recess 2A into the casing 1, and 21 and 22 designate seal members that seal the pressure chamber 18.

The hydraulic motor according to the prior art has the above-mentioned configuration, and its operation will be explained next.

First, an output shaft (not shown) is spline-coupled to the output shaft mounting portion 2B of the rotor 2, so that the output shaft and the rotor 2 can rotate together. Then, by introducing fluid pressure into the pressure chamber 18 through the fluid passage 19, the pushing piston 14 is displaced in a direction away from the friction plate 16 against the urging force of the spring 15, and the brake is released. shall be. Thereafter, for example, the suction/discharge passage 10 is connected to a hydraulic bonder to supply pressure oil to the passage 10, and the suction/discharge passage 11 is connected to a tank so that the returned oil is returned to the tank.

As a result, pressure oil is supplied into the cylinder 3 via the port 8 and presses the piston 4 radially outward. and,
Since the rotation center of the rotor 2 is eccentric with respect to the rotation center of the cam surface ID, the piston 4 is extended while the shoe 5 slides and rotates along the cam surface ID due to the liquid discharge acting on the piston 4. . In this way piston 4
When the cylinder 3 reaches its top dead center, the cylinder 3 switches to a state in which it communicates with the boat 9 on the return oil side, and the piston 4 contracts while discharging the oil in the cylinder 3 from the port 9 while the rotor 2 rotates. can continue. In this way, the rotor 2 is rotated, and the output shaft attached to the output shaft attachment part 2B is rotationally driven.

Next, when the supply of pressure oil to the suction u1 passage 10 is stopped, the rotation of the hydraulic motor is stopped. Thereafter, when the fluid pressure is discharged from the pressure chamber 18, the pushing piston 14 is slid in the direction away from the front casing IB by the action of the spring 15, and the friction plate 16 is moved between the pushing piston 14 and the mounting member 13.
When the friction plate 16 is pressed and clamped between the step portion 13B and the step portion 13B, the friction plate 16 becomes unrotatable. The inner circumferential surface of the friction plate 16 is connected to the groove line portion 17 at the output shaft mounting portion 2 of the rotor 2.
Since the rotor 2 is spline-coupled with the rotor 2, a braking action is performed on the rotor 2, and the rotor 2 becomes unable to rotate. For this reason, when the hydraulic motor is used, for example, as a traveling device or a turning device for construction machinery, even when an external force is acting on the output shaft, such as when the construction machinery is stopped on a slope, the hydraulic motor It will not rotate in vain.

By the way, as mentioned above, in the hydraulic motor according to the prior art, the brake device [12] is disposed outside the casing 1, so the hydraulic motor is elongated in the axial direction, and its overall structure is As the brake device 1 increases in size,
All the parts constituting part 2 are made of separate members from the main body of the hydraulic motor, so there are disadvantages such as an increase in the number of parts, a complicated structure, and difficulty in manufacturing and assembling. .

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and is a radial brake system that incorporates a brake device into the main body of a hydraulic motor to reduce its overall shape and reduce the number of parts. The object is to provide a piston type hydraulic motor.

In order to achieve the above-mentioned object, the radial piston type hydraulic motor according to the present invention has a fitting part between a distribution valve and a rotor formed in a tapered shape, and a brake device made slidable on a front casing. A pushing piston is provided, a spring is formed between the front casing and the pushing piston, the spring pushes the pushing piston toward the side of the rotor, and the pushing piston is formed between the front casing and the pushing piston, and the pushing piston is formed between the front casing and the pushing piston. The piston is characterized by being composed of a pressure chamber that slides and displaces the piston in a direction to separate it from the rotor.

Embodiments of the present invention will be described below with reference to FIG.

In this figure, the same constituent elements as those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

However, the distribution shaft 31, which is provided integrally with the rear casing IA, has a tapered shape whose diameter decreases toward its tip. Further, the recessed portion 32A of the rotor 32 is connected to the distribution shaft 31.
It has a tapered shape that matches the Then, the rotor 3
The output shaft mounting portion 32B of No. 2 does not have a spline groove formed on its outer circumferential surface, which is different from that of the prior art.

Next, 33 indicates a brake device and 1. The brake device 3
3 is provided on the inner circumferential portion of a front casing 34 which together with the rear casing IA and the cam portion IC constitutes the main casing 1'. That is, a pushing piston 35 is provided on the inner circumferential surface of the front casing 34 so as to be slidable in the axial direction. Further, a cover 36 is fixedly provided on the outer surface of the front casing 34, and the cover 36
A spring 37 is interposed between the push piston 35 and the push piston 35, and the spring 37 pushes the push piston 35 in a direction in which it presses against the side surface of the rotor 32.

A step portion 34A is formed on the inner circumferential side of the front casing 34 on the inner side, and an annular pressure chamber is formed between the step portion 34A and the pushing piston 35. 38 is formed. And the pressure chamber 38
The other end of a fluid passage 39 is opened in the front casing 34 and has one end connected to a fluid pressure source.

Furthermore, 40 indicates a bottle provided between the push piston 35 and the cover 36, and the push piston 35 is held so as not to rotate even while the rotor 32 is rotating. Further, reference numeral 41 denotes a restrictor oil reservoir which is bored in the rotor 32 and opens into the cylinder 3 at one end and opens from the side surface of the rotor 32 toward the surface of the pushing piston 35 at the other end.

Although the present invention is constructed as described above, the operation of the hydraulic motor itself is not particularly different from that of the prior art described above.

However, in the brake device 33, under normal conditions, the pushing piston 35 is pushed to the left in the figure by the action of the spring 37, and is pressed against the side surface of the rotor 32, and the rotor 32 is also pushed to the left in the figure. Ru. Then, the recess 32 of the rotor 32
Since both the inner circumferential wall A and the outer circumferential surface of the distribution shaft 31 are tapered, the inner circumferential wall of the concave portion 32A of the rotor 32 is pressed against the outer circumferential surface of the distribution shaft 31 as the rotor 32 is pressed to the left in the figure. be done. In this way, the brake force is obtained by the pressing force between the pushing piston 35 and the side surface of the rotor 32 and the pressing force between the inner peripheral surface of the recess 32A of the rotor 32 and the outer peripheral surface of the distribution shaft 31, The rotor 32 is in a state where it cannot rotate due to the braking action. Therefore, the output shaft mounting portion 3
When an external force is applied to the output shaft connected to the output shaft 2B, the hydraulic motor is activated.In order to release the brake from the brake device 33, fluid pressure is applied to the pressure chamber 38 through the fluid passage 39. As a result, the pushing piston 35 is displaced in a direction spaced by ml from the side surface of the rotor 32, and the pushing force of the rotor 32 to the right in the figure is released. For this purpose, the rotor 32
If the rotor 32 is in a rotatable state, for example, when the suction and discharge passage 10 is connected to a hydraulic pumper and pressure oil is supplied to the suction and discharge passage 10, and when the other suction and discharge passage 11 is connected to a tank, the rotor 32 is rotated. It will be done. And suction ff1 passage 10
When pressure oil flows into the cylinder 3 through the suction port 8, the rotor 32 is pushed to the right in 121 by this oil pressure, and the inner circumferential wall of the four parts 32A and the outer circumferential surface of the distribution shaft 31 A slight gap is formed between the two, and leaked oil from the suction/exhaust ports 8 and 9 is present in this gap, forming a lubricating oil film, allowing the rotor 32 to rotate smoothly.

In this way, when the rotor 32 is displaced to the right in the figure, the side surface of the rotor 32 comes close to the pushing piston 35 again. However, since a throttle oil reservoir 41 is installed on the side surface of the rotor 32, one end of which opens into the cylinder 3 and the other end of which opens toward the push piston 35, when the rotor 32 approaches the push piston 35, The pressure inside the cylinder 3 acts on the pushing piston 35 through the throttle oil filler 41, and the pushing piston 35 is further displaced to the right in the figure, and the reaction force causes the rotor 32 to move to the left in the figure. Pressed by As a result, the inconvenience of wear caused by the side surface of the rotor 32 sliding on the push piston 35 during rotation is prevented, and the gap between the inner peripheral wall of the recess 32A of the rotor 32 and the outer peripheral surface of the distribution shaft 31 is adjusted. This prevents excessive leakage of oil from the suction and discharge ports 8 and 9. In this case, squeeze oil container 4
Since only a small amount of pressure oil will flow out from cylinder 1, the pressure loss within cylinder 3 will not become very large.

Furthermore, when the rotor 32 rotates, a force in the rotational direction acts on the push piston 35, but since the movement of the push piston 35 in the rotational direction is restricted by the pin 40, there is no force when it is displaced in this direction. , the wear of the sealing members 21,22 is reduced.

In order to switch the brake device 33 to the braking state again after the hydraulic motor has stopped, the fluid pressure is discharged from the pressure chamber 38 and the pushing piston 35 is displaced to the left in the figure by the action of the spring 37. .

Here, if the recess 32A of the rotor 32 and the chi/generating angle of the distribution shaft 31 are set to be optimal, sufficient braking torque can be obtained even if the spring force of the spring 37 is relatively small.

In addition, in the above-mentioned embodiment, the distribution shaft 31 is connected to the rear casing I.
Although it has been described as being provided integrally with the distribution shaft 31
may be formed separately from the rear casing IA. Also,
Although a disc spring is shown in the drawing as the spring 37, a coil spring or the like may also be used. Furthermore, the fluid pressure introduced into the pressure chamber 38 may be hydraulic pressure or pneumatic pressure. Furthermore, although the rear casing IA, the cam IC, and the front casing 34 are formed separately, the cam IC may be formed integrally with the casing IA or the front casing 34.

As explained in detail above, the lagal piston type hydraulic motor according to the present invention has a configuration in which four brakes are housed in the hydraulic motor main body, so the axial dimension is shortened, and the hydraulic motor The overall shape of the device becomes smaller. The configuration is such that the push piston slides directly on the front casing, and the braking force is applied through contact between the push piston and the side surface of the rotor and between the inner peripheral wall of the rotor's recess and the outer periphery I11 of the distribution shaft. Therefore, there is no need for multiple members or friction plates as in the prior art, and there is no need to form a snow line groove on the outer circumferential surface of the rotor's output shaft attachment part, so the structure is simple and the number of parts is reduced, and therefore the hydraulic motor This has the effect of making manufacturing and assembly easier.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a conventional hydraulic motor, and FIG. 2 is a longitudinal cross-sectional view of a hydraulic motor according to an embodiment of the present invention. 1'...Body casing, IA...Rear casing, 1C river force section, 1■)...Cam surface, 31...Distribution shaft, 32...Rotor, 32A...Concavity, 33 ...
Brake device ff, 34...front casing, 3
5... Jllll! [Iku piston, 37...shi'', 38...pressure chamber. Patent Demi (Person El Ritsu Construction Machinery Co., Ltd. Agent and Attorney Kazuhiko Hirojun Figure 1 Figure 2

Claims (1)

[Claims] A main body casing consisting of a rear casing, a front casing, and a cam part provided between the casings and having a cam surface formed on its inner surface, and a rotor disposed within the main casing and rotating eccentrically with respect to the cam surface. , a Radia-Ruviston hydraulic motor comprising: a distribution valve fixed to the rear casing and fitted into the rotational center of the rotor; and a brake device that performs a braking action against rotation of the rotor; a pushing piston having a tapered fitting portion therebetween, and the brake device being slidably provided on the front casing; and a spring pushing the pushing piston toward a side surface of the rotor. and a pressure chamber formed between the front casing and the pushing piston, which slides and displaces the pushing piston in a direction away from the rotor by introducing fluid pressure. Features a radial piston type hydraulic motor.