JP3603014B2 - Hydraulic motor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic motor used for a construction machine or the like.
[0002]
[Prior art]
A hydraulic motor is used to drive a block of a traveling crawler of a construction machine and a roller of a road roller. Such a hydraulic motor is integrally assembled with a planetary gear reduction device, and reduces the rotation of the output shaft of the hydraulic motor to rotationally drive the sprockets and rollers.
[0003]
The planetary gear reduction device has a first sun gear fixed to an output shaft of a hydraulic motor, a plurality of planetary gears meshing with the first sun gear, and an annular internal gear, and a planetary gear meshing with the inside. 2 sun gears. The plurality of planet gears are connected by a carrier, and orbit around the first sun gear as a unit.
[0004]
The planetary gear reduction device is usually provided with two or three sets of such a sun gear, a planetary gear and an internal gear. For example, when two stages are provided, the second stage sun gear is rotationally driven by the carrier of the first stage planetary gear, and a plurality of planetary gears are meshed around this sun gear. This second stage planetary gear further meshes with the internal gear on the outside thereof. Then, the second stage planetary gear is fixed to the motor casing to prevent revolving, so that the internal gear is rotated at a reduced speed.
[0005]
The motor casing is fixed to the vehicle side, and a roller or a sprocket to be driven is mounted on a rotating drum to which the internal gear is fixed. In this way, the rotation of the output shaft of the hydraulic motor can be reduced to drive the rollers or sprockets to rotate.
[0006]
[Problems to be solved by the invention]
As described above, in the hydraulic motor including the planetary gear reduction device, the rotation of the internal gear is output as a reduced output by fixing the planetary gear. Since a very large load acts on this support shaft, it must be firmly fixed to the motor casing, and there are several methods for that purpose.
[0007]
First, as a first method, there is a method in which a recess is formed in a motor casing, and a support shaft is press-fitted into the recess and fixed by tight fitting. However, when fixing with an interference fit, it is necessary to ensure a sufficient thickness for the motor casing, and if so, the motor casing becomes large and heavy. In addition, when press-fitting, a large press machine is required, and the manufacturing cost increases.
[0008]
As a second method, there is a method in which a support shaft is formed integrally with a motor casing by shaving the motor casing when the motor casing is formed. In this case, when a load is applied to the support shaft, stress concentrates at the boundary between the support shaft and the motor casing, so that the support shaft must be formed from a material having high rigidity to withstand the concentration of stress, thereby greatly reducing the manufacturing cost. There is a problem that it becomes high.
[0009]
As a third method of fixing the support shaft and the motor casing, there is a method of fixing the support shaft to the motor casing with bolts. However, in this case, the bolts may be loosened due to vibration during use, and the support shaft may fall out of the motor casing.
[0010]
An object of the present invention is to provide a hydraulic motor in which a support shaft for supporting a planetary gear is securely fixed to a motor casing at low cost without increasing the size of the motor.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a hydraulic motor including a planetary gear reduction unit, wherein a support shaft that supports the planetary gear is fixed to a motor casing.
A fitting recess into which the support shaft fits is formed in the motor casing,
At the tip of the support shaft that fits into the fitting recess, a shaft-side locking groove is formed over the entire circumference,
On the inner peripheral portion of the fitting concave portion, a concave side locking groove is formed over the entire circumference,
It has elasticity and has a locking ring that can be fitted to the shaft side locking groove and the recess side locking groove,
With the locking ring fitted in the shaft-side locking groove, insert the tip of the support shaft into the fitting recess of the motor casing, and insert the locking ring into the shaft-side locking groove and the recess-side locking groove. The hydraulic motor is characterized in that the support shaft is locked so as to prevent the support shaft from coming off and fixed to the motor casing.
[0012]
According to the present invention, in order to fix the support shaft to the motor casing, first, the support ring is elastically reduced in diameter and fitted in the shaft side locking groove formed at the tip of the support shaft. Insert the shaft into the fitting recess formed in the motor casing. Since the locking ring has elasticity, when the support shaft is fitted into the fitting recess, the locking ring expands in diameter and resiliently comes into contact with the inner peripheral surface of the fitting recess. In this state, the support shaft is further inserted, and when the shaft side locking groove coincides with the recess side locking groove, the locking ring resiliently fits into the recess side locking groove. In this way, the locking ring is fitted and locked in the recess side locking groove and the support shaft side locking groove, so that the support shaft is prevented from coming off.
[0013]
As described above, when the support shaft is pressed into the motor casing, it is necessary to secure a sufficient thickness to the motor casing. However, in the present invention, the support shaft is simply fitted into the fitting recess. Therefore, it is not necessary to increase the thickness of the motor casing, and it is not necessary to increase the size of the motor body. Further, since the support shaft is not formed by shaving, only the support shaft may be formed of a material having high rigidity, and the manufacturing cost can be reduced. Further, in the present invention, since the retaining ring is not retained by the locking ring and is not retained by the bolt, the support shaft does not come off due to vibration or the like and can be securely held.
[0014]
According to the second aspect of the present invention, of the planes defining the shaft-side locking groove, a side surface on a distal end side of the support shaft is inclined toward a distal end side of the support shaft toward a radially outward side of the support shaft. It is characterized by.
[0015]
According to the present invention, the side surface on the distal end side of the support shaft of the shaft side locking groove is formed so as to be inclined toward the distal end as it goes radially outward of the support shaft. Due to the inclined side surface, an outward force acts on the locking ring. That is, a force acts on the locking ring on the side where the diameter increases, and the locking ring is prevented from being reduced in diameter and the entire locking ring is buried in the shaft-side locking groove.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a sectional view showing a configuration of a hydraulic motor 1 according to an embodiment of the present invention. The hydraulic motor 1 includes a motor body 2, a rotating drum 3, and a planetary gear unit 4. The rotating drum 3 has a substantially cylindrical shape with a bottom, and is coaxial with an axis L <b> 1 of an output shaft 5 of the motor body 2. 2 is attached. A bearing 7 is interposed between the rotating drum 3 and the motor casing 6 of the motor body 2, and the rotating drum 3 is rotatably supported by the motor casing 6 around the axis L1. The planetary gear unit 4 is built in the rotary drum 3 and drives the rotary drum 3 to rotate by reducing the rotation of the output shaft 5 of the motor body 2. Such a hydraulic motor 1 is provided, for example, on a load roller, the motor casing 6 is fixed to the vehicle side, the rotary drum 3 is fixed to the roller side, and the rotation of the output shaft 5 is reduced to drive the roller. In this embodiment, the motor body 2 is a swash plate type piston motor.
[0017]
The planetary gear reduction device 4 is composed of two stages, a first stage sun gear 10 fixed to the tip of the output shaft 5, two planetary gears 11 meshing with the sun gear 10, and a rotating drum 3. An internal gear 12 formed integrally with the peripheral portion; a second-stage sun gear 13 rotatably mounted on the output shaft 5 inside the sun gear 10 (to the right in FIG. 1); And a second stage sun gear 13 that meshes with the second stage sun gear 13 and three second stage planetary gears 14 that mesh with the second stage sun gear 13. The internal gear 12 is formed on the inner peripheral portion of the rotary drum 3, and the first stage planetary gear 11 and the second stage planetary gear 14 mesh with each other. The two first-stage planetary gears 11 are arranged diagonally around the output shaft 5 and are rotatably supported by the support shaft 16 respectively. The two support shafts 16 are connected by a carrier 15, and the two planetary gears 11 revolve around the sun gear 10 by the rotation of the sun gear 10 integrally.
[0018]
The second stage sun gear 13 is connected to the carrier 15 to transmit the torque, and rotates with the carrier 15 around the axis L1. The three second-stage planetary gears 14 meshing with the second-stage sun gear 13 and the internal gear 12 are rotatably supported by a support shaft 17, which is fixed to the motor casing 6 and The revolution of the planetary gear 14 at the stage is prevented. Therefore, when the sun gear 10 is rotated by the rotating shaft 5, the rotating drum 3 on which the internal gear 12 is formed is reduced in speed and rotates around the axis L1.
[0019]
Thus, the second stage planetary gear 14 needs to be fixed to the motor casing 6 in order to prevent revolving. For this purpose, the tip 17a of the support shaft 17 that supports the planetary gear 14 is fitted into the motor casing 6. And fix it.
[0020]
FIG. 2 is an enlarged sectional view showing the vicinity of the distal end portion 17a of the support shaft 17. As shown in FIG. The support shaft 17 has a distal end 17 a fixed to the motor casing 6, and a planetary gear 14 mounted on a base end 17 b via a bearing 18 so as to be rotatable around the axis L <b> 2 of the support shaft 17. A fitting recess 24 into which the tip portion 17a of the support shaft 17 fits is formed in the motor casing 6 in parallel with the axis L1 of the output shaft 5. On the inner peripheral portion near the bottom of the fitting concave portion 24, a concave side engaging groove 21 is formed over the entire circumferential direction. A shaft-side locking groove 20 is formed in the distal end portion 17a of the support shaft 17 over the entire circumference in the circumferential direction. The shaft-side locking groove 20 and the recess-side locking groove 21 have a substantially C-shaped engagement. The retaining ring 22 is fitted to prevent the support shaft 17 from coming off. The support shaft 17 is formed with a screw hole 25 penetrating along the axis L2.
[0021]
The locking ring 22 has elasticity, is substantially C-shaped, and has a diameter larger than at least the inner diameter of the fitting recess 24 in a natural state where no external force acts. Therefore, when the distal end portion 17a of the support shaft 17 is inserted into the fitting recess 24 while the locking ring 22 is reduced in diameter against the elastic force and fitted in the shaft side locking groove 20, the locking ring Reference numeral 22 resiliently contacts the inner peripheral surface of the fitting recess 24 by the elastic restoring force. In this state, the support shaft 17 is further pushed into the fitting recess 24, and when the shaft side locking groove 20 and the recess side locking groove 21 coincide with each other, the locking ring 22 resiliently engages with the recess side locking groove 21. And the locking ring 22 is fitted in both the recess side locking groove 21 and the shaft side locking groove 20 to prevent the support shaft 17 from coming off.
[0022]
An intermediate fit between the fitting recess 24 and the support shaft 17 is sufficient. Therefore, there is no need to press-fit with a large-sized press as in the prior art, and the assembling work can be easily performed. Further, since no interference is substantially formed, a large wall thickness is not required and the motor casing 6 does not need to be large.
[0023]
In this embodiment, the motor casing 6 is formed of cast iron, and the support shaft 17 is formed by carburizing and quenching chromium molybdenum steel. In the related art in which the motor casing and the support shaft are integrally formed by cutting out, it is necessary to integrally form the motor casing and the support shaft with a hard material in order to increase rigidity. Since the shaft 17 and the motor casing 6 can be manufactured separately, only the support shaft 17 can be made of a hard material, and the manufacturing cost can be reduced.
[0024]
In the related art in which the support shaft 17 is prevented from coming off by the bolt, the bolt may be loosened due to the vibration, and the support shaft 17 may come out. The shaft 17 is reliably prevented from coming off.
[0025]
Since the screw hole 25 is formed through the support shaft 17, when the support shaft 17 is fitted into the fitting recess 24, the air in the recess 24 is exhausted through the screw hole 25, and The compression of the air in the place 24 is prevented. The length of the support shaft 17 to be fitted is about half the length of the support shaft 17, whereby the support shaft 17 is securely fixed to the motor casing 6.
[0026]
FIG. 3 is an enlarged sectional view showing the vicinity of a locking ring 22 fitted and locked in the recess side locking groove 21 and the shaft side locking groove 20. The locking ring 22 is formed by bending a hard steel wire having an outer diameter φ of about 2 to 3 mm into a C shape. The shaft side locking groove 20 is formed so that the depth d is larger than the outer diameter φ of the locking ring 22 so that the locking ring 22 can be completely fitted and buried, and the width W is also equal to the outer diameter. When the shaft-side locking groove 20 reaches the recess-side locking groove 21, the locking ring 22 smoothly projects from the shaft-side locking groove 20 so as to protrude from the recess-side locking groove. 21 fits.
[0027]
The locking ring 22 needs to be fitted and locked in the recess side locking groove 21 and the shaft side locking groove 20, so that the depth d2 of the recess side locking groove 21 is about φ / 2. To be elected. Since half of the locking ring 22 having a circular cross section fits into the recess side locking groove 21, the cross section may have a semicircular shape.
[0028]
As shown in FIG. 3, the shaft-side locking groove 20 is formed to be inclined toward the distal end 17 a (to the right in FIG. 3) toward the outside in the radial direction of the support shaft 17 (upward in FIG. 3). At least, among the planes defining the shaft-side locking groove 20, the side surface 31 on the distal end portion 17a side of the support shaft 17 is inclined toward the distal end portion 17a toward the radially outward side of the support shaft 17, When a pulling force acts on the support shaft 17, the locking ring 22 is guided radially outward by the side surface 31, and is pressed against the concave locking groove 21 side. When the pull-out force acts in this manner, the locking ring 22 is pressed into the recess-side locking groove 21 instead of being buried in the shaft-side locking groove 20, so that the locking ring 22 resists the pull-out force. As a result, the support shaft 17 is reliably prevented from being pulled out by being reliably locked in the recess side locking groove 21.
[0029]
Further, since the shaft side locking groove 20 is formed so as to be inclined, when the support shaft 17 is fitted into the fitting recess 24, the locking ring is formed on the surface of the motor casing 6 around the fitting recess 24. The support shaft 17 can be inserted while pushing the shaft 22 into the shaft side locking groove 20, and the assembling work is also facilitated.
[0030]
In this embodiment, the planetary gear reduction device 4 is a two-stage planetary gear reduction device. However, the present invention is not limited to this, and may be a three-stage planetary gear reduction device. The support shaft of the planetary gear of the stage is fitted and fixed in the motor casing. Also, a single-stage planetary gear reduction device is possible.
[0031]
Further, in the present embodiment, the motor main body 2 is a swash plate type piston motor. However, the present invention is not limited to this, and may be a swash shaft type piston motor or another hydraulic motor.
[0032]
【The invention's effect】
According to the first aspect of the present invention, the motor is provided by fitting the support shaft into the fitting recess of the motor casing, locking the support shaft withdrawal by the locking ring, and fixing the support shaft to the motor casing. The support shaft can be securely fixed to the motor casing at low cost without increasing the size.
[0033]
According to the second aspect of the present invention, since the side surface of the shaft-side locking groove is formed to be inclined, it is possible to reliably prevent the support shaft from being pulled out.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of a hydraulic motor 1 according to an embodiment of the present invention.
FIG. 2 is an enlarged sectional view showing the vicinity of a distal end portion 17a of a support shaft 17.
FIG. 3 is an enlarged sectional view showing the vicinity of a locking ring 22 locked in a shaft-side locking groove 20 and a recess-side locking groove 21;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydraulic motor 2 Motor body 3 Rotary drum 4 Planetary gear reduction device 5 Output shaft 6 Motor casing 10, 13 Sun gear 11, 14 Planetary gear 12 Internal gear 15 Carrier 20 Shaft side locking groove 21 Concave side locking groove 22 Stop ring 31 side

Claims (2)

In a hydraulic motor including a planetary gear reduction unit, a support shaft that supports the planetary gear is fixed to a motor casing,
A fitting recess into which the support shaft fits is formed in the motor casing,
At the tip of the support shaft that fits into the fitting recess, a shaft-side locking groove is formed over the entire circumference,
On the inner peripheral portion of the fitting concave portion, a concave side locking groove is formed over the entire circumference,
It has elasticity and has a locking ring that can be fitted to the shaft side locking groove and the recess side locking groove,
With the locking ring fitted in the shaft-side locking groove, insert the tip of the support shaft into the fitting recess of the motor casing, and insert the locking ring into the shaft-side locking groove and the recess-side locking groove. A hydraulic motor characterized in that the support shaft is locked to prevent the support shaft from coming off and fixed to a motor casing. The side surface on the tip side of the support shaft among the planes defining the shaft side locking groove is inclined toward the tip end side of the support shaft as going outward in the radial direction of the support shaft. Hydraulic motor.

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