JP2000009017A - Variable displacement swash plate type hydraulic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce whole size and gross weight by suppressing an outer diameter of a casing on which a hydraulic pressure passage is formed, even when a decelerator or the like is attached to the casing. SOLUTION: Spline grooves 3 are formed on an inner peripheral side of a cylindrical part 1A of a casing 1 along a circumferential direction with equal spacings. An outer peripheral side of a fixed brake plate 20 composing a part of a brake device 19 is fitted to the spline grooves 3. A hydraulic pressure passage 16 is formed on the casing 1 for supplying and discharging pressure oil in respect to a tilting control actuator for tilting a swash plate. The hydraulic pressure passage 16 is arranged on the side of a projection 1A1 between the spline grooves 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement swash plate type hydraulic motor suitably used as a hydraulic motor for construction machines such as a hydraulic shovel.

[0002]

2. Description of the Related Art In general, a construction machine such as a hydraulic shovel is provided with a hydraulic motor as a turning motor or a traveling motor. The construction of this hydraulic motor by a variable displacement swash plate type hydraulic motor is known, for example, from Japanese Patent Application Laid-Open No. 9-188280.

[0003] The hydraulic motor has a casing having an open end on one end side and a stepped portion on an inner peripheral surface on the opening side, a rotating shaft rotatably provided in the casing, and a rotating shaft integrally rotating with the rotating shaft. A rotor provided in the casing and having a plurality of cylinders formed in the axial direction; and a plurality of rotors each having one end in the axial direction slidably inserted into each cylinder of the rotor and the other end protruding from each cylinder. A piston,
A plurality of shoes respectively provided on the protruding side of each piston, and each shoe slides when the rotor rotates, the plurality of shoes being provided on the casing at the protruding end side of each piston so as to be tiltable. A swash plate, a tilt actuator that is provided between the swash plate and the casing at the other axial end of the casing, and that tilts and drives the swash plate by supplying and discharging oil liquid; and the tilt actuator. An oil passage provided in the axial direction of the casing to supply and discharge pressure oil for tilt control from the outside to the cylinder portion, and is located between a step portion on the opening side of the casing and the rotor. A negative-type brake device provided and supplied / discharged with an oil liquid serving as a brake release pressure.

In this type of conventional hydraulic motor, each piston is sequentially extended from the inside of each cylinder by sequentially supplying pressure oil from the outside into each cylinder through a supply / discharge port provided on the casing side. As a result, the shoe provided on the tip side of each piston is sequentially pressed against the swash plate, and at this time, the drive shaft integrated with the rotor is driven by the reaction force from each swash plate acting on each cylinder via each piston. Let it.

In this prior art, the tilt actuator is actuated by external pressure oil,
The tilt angle of the swash plate is controlled. When the tilt angle of the swash plate is maximized, the drive shaft can be rotated at low speed and with high torque. When the tilt angle of the swash plate is minimized, the drive shaft can be rotated at high speed and with low torque.

Further, the brake device is provided with a fixed-side friction plate provided in engagement with a spline groove formed in a step portion of a casing, and arranged alternately with the fixed-side friction plate provided on an outer periphery of a rotor. It is composed of a rotation-side friction plate and a brake piston or the like which is provided movably in the axial direction on a step portion of the rotor, and which brings these friction plates into and out of contact with each other.

[0007]

According to the above-mentioned prior art, when the oil passage is arranged close to the inner peripheral side of the casing, the outer diameter of the casing can be made smaller.
This is advantageous in that the entire casing can be reduced in size in the radial direction.

However, in this prior art, the oil passage is provided on the inner peripheral side of the casing as described above, since the step portion of the casing is provided with a spline groove in which the rotating friction plate of the brake device is engaged. When they are arranged close to each other, there is a problem in that the distance between the oil passage through which the high-pressure oil flows and the spline groove is narrowed in the radial direction, the thickness between the two becomes thin, and the strength of the casing is reduced.

Then, there is a possibility that the thick portion between the oil passage and the spline groove may be damaged. In this case, the pressure oil in the oil passage leaks into the casing, and the tilt actuator is operated with high accuracy. There is a problem that it becomes difficult.

When the thick portion between the oil passage and the spline groove is formed to be thin in this way, casting defects are liable to occur in the thick portion at the time of casting of the casing, which also increases the strength of the casing. Is reduced.

Therefore, in order to avoid such a problem, the oil passage is arranged in a state radially sufficiently separated from the spline groove, and a thick portion between the oil passage and the spline groove is formed thick. By doing so, a method of increasing the strength of the casing can be considered.

However, in this case, the outer diameter of the casing is increased by the thickness of the space between the oil passage and the spline groove, and accordingly, the entire apparatus including the speed reducer mounted on the casing is provided. However, there is a problem that the size increases in the radial direction.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can reduce the outer diameter of a casing in which an oil passage is integrally formed, and can reduce the size of the casing and provide a sufficient casing. Strength can be secured,
For example, it is an object of the present invention to provide a variable displacement swash plate type hydraulic motor capable of reducing the overall size and weight even when a reduction gear or the like is provided in a casing.

[0014]

In order to solve the above-mentioned problems, a swash plate type hydraulic rotary machine according to the present invention comprises: a casing having an opening at one end side and a step portion on an inner peripheral surface at the opening side; A rotary shaft rotatably provided on the rotor, a rotor provided in the casing so as to rotate integrally with the rotary shaft and having a plurality of cylinders formed in an axial direction, and one end in the axial direction is provided in each cylinder of the rotor. A plurality of pistons that are slidably inserted into the other end and protrude from the respective cylinders, a plurality of shoes respectively provided on the protruding sides of the respective pistons, and a plurality of shoes positioned on the protruding end sides of the respective pistons. A swash plate that is tiltably provided on the casing and slides when the rotor rotates, and is provided between the swash plate and the casing located at the other axial end of the casing;
A tilt actuator that tilts and drives the swash plate by supplying and discharging an oil liquid, and a tilt actuator that is provided in an axial direction of the casing to supply and discharge pressure oil for tilt control from outside to a cylinder portion of the tilt actuator. And a negative-type brake device provided between the rotor and the stepped portion of the casing on the opening side of the casing and for supplying and discharging an oil liquid as a brake release pressure.

The first aspect of the present invention is characterized in that a plurality of spline grooves extending in the axial direction are provided in the step portion of the casing at intervals in the circumferential direction, and the brake device is provided in the casing. A fixed-side friction plate provided on the stepped portion in engagement with each of the spline grooves; and a rotating-side friction plate provided on the outer periphery of the rotor and provided alternately with the fixed-side friction plate, and an oil passage is provided. Is configured such that at least the step side of the casing is located between adjacent spline grooves.

With this configuration, at least on the step side of the casing, the oil passage can be located between the adjacent spline grooves, so that the oil passage is brought closer to the inner peripheral side of the cylindrical portion of the casing. Even in the case of the arrangement, the thick portion between the oil passage and the spline groove does not become thin, and the thickness around the oil passage can be made thick.

According to the second aspect of the present invention, the oil passage extends obliquely inward in the radial direction at least with the step of the casing toward the tilt actuator.

With such a configuration, the oil passage can be inclined obliquely in accordance with the shape of the step, and the oil passage can be arranged closer to the step.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A variable displacement swash plate type hydraulic motor according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking an example in which the present invention is applied to a traveling hydraulic motor.

Here, FIGS. 1 to 6 show an embodiment according to the present invention. In the drawings, reference numeral 1 denotes a casing of a hydraulic motor, and the casing 1 is formed in a bottomed tubular shape opened at one end side by a tubular portion 1A and a bottom portion 1B as shown in FIGS. An annular flange 1C is integrally formed on the outer peripheral side of the cylindrical portion 1A.
A seal mounting groove 1D is formed over the entire circumference between the flange and the flange 1C.

The casing 1 has a flange portion 1C fixed to a track frame of a hydraulic shovel, for example, using bolts (not shown) or the like, and an opening end side of the cylindrical portion 1A is covered by a lid 2 as a rear casing. The structure is closed.

Here, on the inner peripheral side of the cylindrical portion 1A of the casing 1, there is formed a brake mounting step portion 1E whose diameter is increased in three stages toward the opening side as shown in FIG. A spline groove 3 described later is formed in the portion 1E. The inner peripheral side of the cylindrical portion 1A is a protruding portion 1A1 that protrudes radially inward between adjacent spline grooves 3.

Reference numerals 3, 3,... Denote spline grooves provided on the inner side of the brake mounting step 1D of the casing 1. The spline grooves 3 are, as shown in FIGS. The side is formed as a semicircular notched concave groove extending in the axial direction, and is arranged apart from each other along the circumferential direction.

Here, as shown in FIG. 4, the spline groove 3 has a groove depth d set to, for example, about 5 to 20 mm. Also, each spline groove 3 is 20 to
They are arranged at equal intervals on the inner peripheral side of the cylindrical portion 1A with a central angle α of about 35 degrees.

Reference numeral 4 denotes a drive shaft as a rotation shaft rotatably provided in the casing 1. Reference numeral 5 denotes a rotor rotatably provided in the casing 1 so as to rotate integrally with the drive shaft 4. A plurality of cylinders 6 are formed around the drive shaft 4 and are spaced apart from each other and extend in the axial direction. Also,
On the outer peripheral side of the rotor 5, spline grooves 7, 7,... Substantially similar to the spline grooves 3 on the casing 1 side are provided at equal intervals in the circumferential direction, as shown in FIGS.

Reference numeral 8 denotes a valve plate located between the lid 2 and the rotor 5 and fixed to the lid 2. The valve plate 8 is intermittently connected to each cylinder 6 of the rotor 5 as shown in FIG. A pair of supply / discharge ports 8A (only one is shown) that communicates with each other, and each of the supply / discharge ports 8A communicates with a pair of supply / discharge passages 9 (only one is shown) formed on the lid 2 side. .

Reference numeral 10 denotes a plurality of pistons. Each of the pistons 10 has one end slidably inserted into each cylinder 6 of the rotor 5 and the other end protruding outside each cylinder 6.
A shoe 11 is provided on the projecting end side of each piston 10 so as to be swingable.

Reference numeral 12 denotes a swash plate provided on the bottom 1B side of the casing 1 so as to be tiltable. The swash plate 12 is provided between the respective shoes 11 on the surface thereof and the bottom 1B side. The tilting support portion (not shown) is used as a fulcrum to tilt. The swash plate 12 changes the stroke amount of each piston 10 according to the tilt angle, and determines the motor capacity of the hydraulic motor based on the stroke amount.

Reference numeral 13 denotes a tilt actuator provided on the bottom 1B side of the casing 1;
As shown in FIG. 2, a cylinder portion 14 provided on the bottom 1B side of the casing 1 at a distance in the radial direction of the drive shaft 4 and a base end side slidably inserted into each of the cylinder portions 14, It is composed of a pair of tilt control pistons 15 and the like, the leading ends of which contact the rear side of the swash plate 12.

Reference numeral 16 denotes an oil passage provided in the axial direction of the casing 1. The oil passage 16 has a base end side opening at an end face on the bottom 1B side of the cylindrical portion 1A and a front end side axially intermediate of the cylindrical portion 1A. And a second passage portion 16B extending obliquely in the cylindrical portion 1A, having a base end side opening at the opening end surface of the cylindrical portion 1A and a distal end side communicating with the first passage portion 16A.
And a third passage portion 16C that connects the first passage portion 16A to the cylinder portion 14. Also,
The base end side of the first passage portion 16A is sealed by a plug 17.

The oil passage 16 is connected to the second passage 1
6B is connected to a displacement control valve 18 provided on the lid 2 side, and the driver of the hydraulic shovel switches the displacement control valve 18 so that the pressure oil from the displacement control valve 18 is transferred to the cylinder unit 14. Is to be supplied and discharged.

Here, the second passage portion 16 of the oil passage 16
B is a brake mounting step 1 as shown in FIGS.
It extends obliquely inward in the radial direction with the E side facing the tilt actuator 13 side. The second passage portion 16B is provided so as to be located on the protruding portion 1A1 side of the cylindrical portion 1A.

Numeral 19 is a negative type brake device for applying a brake to the drive shaft 4 and the rotor 5.
Are fixed-side brake plates 20, 20,... Whose outer peripheral side is engaged with each spline groove 3 of the casing 1 and can move in the axial direction as shown in FIGS. The rotating side brake plates 21 which are provided alternately and whose inner circumferential side is each spline groove 7 of the rotor 5 and which can move in the axial direction are fitted in the brake mounting step 1E so as to be slidable in the axial direction. Brake piston 22 and spring 2
3 and so on.

The brake device 19 defines a hydraulic chamber 24 between the brake piston 22 and the brake mounting step 1E of the casing 1, and the casing 1 has the hydraulic chamber 24 and the hydraulic chamber 24 as shown in FIG. A liquid passage 25 for supplying and discharging the brake release pressure is formed between the opening and the end surface of the cylindrical portion 1A.

Then, the brake device 19 connects the brake piston 22 to each brake plate 20,
21 so that each fixed-side brake plate 20 is brought into frictional contact with each rotation-side brake plate 21 between the brake piston 22 and the brake mounting step 1E.
The rotor 5 is held together with the drive shaft 4 in a braking state as a so-called parking brake. Also, the brake device 1
9 is a brake piston 22 when a brake release pressure is supplied from outside to the hydraulic chamber 24 through the liquid passage 25.
Are separated from the rotation-side brake plate 21, and at this time, the braking of the rotor 5 is released.

Reference numeral 26 denotes a traveling speed reducer provided in the casing 1. The speed reducer 26 has a bottomed cylindrical shape rotatably mounted on the outer peripheral side of the cylindrical portion 1A of the casing 1 as shown in FIG. And a two-stage planetary gear reduction mechanism 28, 29, etc. provided in the housing 27. The sprocket 3
0 is attached.

Reference numerals 31 and 31 denote mechanical seals for sealing between the casing 1 and the housing 27 of the speed reducer 26. The mechanical seal 31 is provided in the seal mounting groove 1D of the casing 1. Reference numerals 32, 32 denote bearings for rotatably supporting the housing 27 with respect to the casing 1, and the bearings 32 are attached to the outer peripheral side of the casing 1 by nuts 33 so as not to be pulled out.

The variable displacement type swash plate type hydraulic motor according to the present embodiment has the above-described configuration. When pressure oil from a hydraulic pump (not shown) is supplied to and discharged from the hydraulic motor, the pressure oil at this time is supplied. Is supplied / discharged into / from each cylinder 6 of the rotor 5 through each supply / discharge passage 9 of the lid 2 and the supply / discharge port 8A of the valve plate 8.

Thus, each of the shoes 11
A pressing force is applied to the swash plate 12 via the swash plate 12, and each of the shoes 11 slides on the swash plate 12 along the circumferential direction by the pressing force,
The rotor 5 integrated with the piston 10 rotates.
The rotational force at this time is transmitted from the drive shaft 4 to the speed reducer 26.

Here, when the driver of the hydraulic shovel or the like switches the capacity control valve 18, the pressure oil from the capacity control valve 18 is supplied and discharged to the cylinder portion 14 of the tilt actuator 13 through the oil passage 16, The rotation control piston 15 is driven to expand and contract.

As a result, the swash plate 12 is tilted by the tilt control piston 15, and the tilt angle of the swash plate 12 is variably controlled. When the tilt angle of the swash plate 12 is maximized, the drive shaft 4 can be rotated at low speed and high torque. When the tilt angle of the swash plate 12 is minimized, the drive shaft 4 can be rotated at high speed. It can be rotated with low torque.

Here, in the present embodiment, the second passage portion 16B of the oil passage 16 is connected to the projecting portion 1 between the spline grooves 3.
Because it is located at A1 and provided on the casing 1,
Even when the oil passage 16 is provided close to the inner peripheral side of the casing 1, the thick portion between the second passage portion 16B and the spline groove 3 is not formed thin, and the second passage portion 16B Can be formed relatively thick with the first passage portion 16A and the third passage portion 16C.

Therefore, according to the present embodiment, the entire oil passage 16 including the second passage portion 16B can be provided closer to the inner peripheral side of the casing 1 and closer to the drive shaft 4 side. As shown in FIG. 6, the outer diameters L1, L2, etc. of the casing 1 can be made smaller by an amount corresponding to the approach of the casing 16. Thereby, the speed reducer 26 mounted on the casing 1
The whole device including the above can be downsized in the radial direction.

Further, the casing 1 can increase the strength of the thick portion between the spline groove 3 and the oil passage 16, and breakage occurs between the two, and the pressure oil in the oil passage 16 flows into the casing 1. The possibility of leakage can be eliminated. Thus, the tilt actuator 13 can be operated with high accuracy, and the performance and the like of the device can be improved.

Further, at the time of casting of the casing 1, casting defects can be prevented from being generated in a thick portion between the oil passage 16 and the spline groove 3, whereby the strength of the entire casing 1 can be increased. Thus, the reliability of the casing 1 can be improved.

Further, the second passage portion 16 of the oil passage 16
B is inclined obliquely inward in the radial direction from the opening-side end face of the casing 1 toward the axial direction.
The entire passage 16B is connected to the brake mounting step 1 of the casing 1.
It can be inclined obliquely according to the shape of E. Thus, the oil passage 16 can be arranged closer to the brake mounting step 1E side, and the size of the casing 1 can be further reduced.

In the embodiment, the first oil passage 16
Although the configuration has been described in which the base end side of the passage portion 16A is opened to the end surface on the bottom portion 1B side of the cylindrical portion 1A of the casing 1, the oil passage 1 may be replaced with, for example, an oil passage 1 as in a modification shown in FIG.
As shown in FIG. 6 ', the first passage portion 16A' has its base end side opened toward the brake mounting step 1E side and its distal end side formed in the third passage portion 1E.
6C '.

In this case, the projecting portion 1F of the cylindrical portion 1A of the casing 1 protruding in the axial direction from the bottom portion 1B.
There is no need to provide the first passage portion 16A 'of the oil passage 16' in the oil passage 16 ', thereby making it possible to further reduce the size of the casing 1 in the radial direction.

[0049]

As described above in detail, according to the first aspect of the present invention, the oil passage for supplying the pressure oil to the tilt actuator is arranged at least between the spline grooves on the step side of the casing. With this configuration, even when the oil passage is arranged closer to the inner peripheral side of the casing, the wall thickness around the oil passage can be made relatively thick.

As a result, the outer diameter of the casing can be made smaller, and the entire apparatus including the reduction gear mounted on the casing can be downsized in the radial direction. Also,
The casing can increase the strength of the thick portion between the oil passage and the spline groove, and can eliminate the possibility that breakage occurs between the two and the pressure oil in the oil passage leaks into the casing. Further, it is possible to prevent casting defects from occurring in the portion between the oil passage and the spline groove during casting of the casing, thereby also increasing the strength of the entire casing and improving the reliability of the casing. it can.

According to the second aspect of the present invention, the oil passage is inclined obliquely inward in the radial direction toward the tilt actuator at least at a position on the step side of the casing. Accordingly, the oil passage can be inclined obliquely, and the oil passage can be disposed closer to the stepped portion, so that the size of the casing can be further reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a traveling hydraulic motor and a speed reducer according to an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of FIG. 1 showing a traveling hydraulic motor as a single unit;

FIG. 3 is a cross-sectional view as seen from a direction indicated by arrows III-III in FIG. 2;

FIG. 4 is an enlarged cross-sectional view of a main part showing an oil passage, a spline groove, and the like in FIG. 3;

FIG. 5 is a partially enlarged view as viewed from a direction indicated by arrows VV in FIG. 4;

FIG. 6 is a longitudinal sectional view showing the casing in FIG. 2 alone.

FIG. 7 is a partial sectional view showing a traveling hydraulic motor according to a modification of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 1E Brake mounting step part 3, 7 Spline groove 4 Drive shaft (rotating shaft) 5 Rotor 6 Cylinder 10 Piston 11 Shoe 12 Swash plate 13 Tilting actuator 14 Cylinder part 16 Oil passage 19 Brake device 20 Fixed side brake plate 21 Rotation Side brake plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hitoshi Kiwada 650 Kandamachi, Tsuchiura-shi, Ibaraki F-term in the Tsuchiura Plant of Hitachi Construction Machinery Co., Ltd. (Reference) 3H084 AA08 AA16 AA43 AA45 BB26 BB30 CC58 CC62 CC70

Claims (2)

[Claims] 1. A casing having an opening at one end side and a stepped portion on an inner peripheral surface on the opening side, a rotating shaft rotatably provided on the casing, and a casing inside the casing so as to rotate integrally with the rotating shaft. A rotor provided with a plurality of cylinders in the axial direction, a plurality of pistons having one end in the axial direction slidably inserted into each cylinder of the rotor and the other end protruding from each cylinder; A plurality of shoes respectively provided on the protruding side of the piston, and a swash plate which is provided on the casing and is tiltably provided on the protruding end side of each of the pistons and slides when the rotor rotates. A tilt actuator that is provided between the swash plate and the casing at the other axial end of the casing, and that tilts and drives the swash plate by supplying and discharging oil liquid; and a cylinder of the tilt actuator. An oil passage provided in the axial direction of the casing to supply and discharge pressure oil for tilt control from the outside to the rotor section; and an oil passage provided between a step portion on the opening side of the casing and the rotor. And a negative type brake device that supplies and discharges an oil liquid as a brake release pressure, wherein the stepped portion of the casing is arranged at an interval in the circumferential direction along the axial direction. A plurality of spline grooves extending along the fixed side, and the brake device includes a fixed-side friction plate provided on the step portion of the casing so as to be engaged with the spline grooves, and a fixed-side friction plate provided on the outer periphery of the rotor. And a rotating-side friction plate alternately provided, wherein the oil passage is arranged so that at least the stepped side of the casing is located between adjacent spline grooves. Plate type hydraulic motor. 2. The variable displacement swash plate type according to claim 1, wherein the oil passage extends obliquely inward in a radial direction toward at least a tilting actuator side at a step portion side of the casing. Hydraulic motor.