JPH0419365A - Inscribed type oil motor - Google Patents

Abstract

PURPOSE:To enhance the mechanical efficiency of the motor by forming in the outer periphery of an outer rotor the recesses being communicated with a suction port as an inner rotor rotates and causing the hydraulic operational pressure to act on the recesses with rotation of each rotor to give a rotating force to the outer rotor. CONSTITUTION:When supplying a pressurized fluid from a suction port 5, this fluid flows into right-side space portions S to cause an inner rotor 3 to rotate in a direction in which these spaces S are enlarged. With rotation of the inner rotor 3, the spaces S are moved while becoming smaller in size and the pressurized fluid is discharged from a discharge port 6. In this inscribed type oil motor, recesses 7 which pass through both side surfaces of an outer rotor are formed in the outer periphery of the outer rotor 2 at equal intervals taken in the circumferential direction. Each of these recesses 7 is formed at a position corresponding to the mount of a corresponding tooth surface 2a of the outer rotor. With this construction, when the recess 7 is made open to the suction port 5 with rotation of each rotor 2, 3, the operating oil from the suction port 5 is permitted to flow into the spaces S. The hydraulic operational pressure of the operating oil is caused to act on the recesses 7 as well, thereby to impart a rotating force to the outer rotor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to an internal oil motor having two gears (an outer rotor and an inner rotor) with a difference in the number of teeth of one.

"Prior Art" As a conventional internal oil motor of this type, those shown in FIGS. 5 and 6 are known.

In this example, the internal oil motor has a ring-shaped outer rotor 2 that is rotatably loosely inserted into a caning l having a cavity 1a, and a support shaft 4 that passes through a casing 1. It is equipped with an inner rotor 3 rotatably supported in an inner space. The inner circumferential surface of the outer rotor 2 has a tooth surface 2a having N teeth (N-7 in the example), and the outer circumferential surface of the inner rotor 3 has (N-1) teeth.
A tooth surface 3a having two teeth is formed respectively, and there is a gap between these tooth surfaces 2a, 3a due to contact between the top of the mountain of the tooth surface 3a of the inner rotor 3 and the inner circumferential surface of the outer rotor 2. A space S is formed by partitioning.

When the inner rotor 3 is rotated around the rotation center 01,
The outer rotor 2 is the center of rotation while maintaining contact with the inner rotor 3. The space S gradually changes its volume by rotating 7 times. When it is located at the part indicated by the symbol A on the straight line passing through the center of rotation 00, Ot, its volume becomes the minimum, and when it is located at the part indicated by the symbols B and Bo, its volume becomes the maximum, and in between. , which gradually increases and decreases with rotation.

Further, in the interior of the casing facing the end surfaces of both rotors 2 and 3, there are provided an inlet port 5 for supplying fluid such as hydraulic oil into the space S, and a discharge port 6 for discharging fluid from the space S. Center of rotation 0. ．． 0. They are provided opposite each other on one side of a straight line connecting the two. The suction port 5 is formed so that its opening direction is along the rotational direction of the outer rotor 2 and the inner rotor 3.

In an oil motor having such a configuration, when pressure fluid is supplied from the suction port 5, this pressure fluid flows into the space on the right side in the figure, and moves the inner rotor 3 in the direction in which these spaces S expand, that is, in the direction indicated by the arrow in the figure. Rotate in the direction shown. As the inner rotor 3 rotates, the space S moves while shrinking, opens into the discharge port 5, and is discharged.

In addition to the trochoid type in this example, the tooth shapes of the teeth iI 2 a and 3 a include an impolicoat type and a cycloid type.

"Problem to be Solved by the Invention" By the way, predetermined clearances are set between the outer rotor 2 and the casing 1 and between the inner rotor 3 and the outer rotor 2, taking machining accuracy into consideration. It is considered that it is better to make this smaller in order to reduce leakage between the spaces S. In particular, if the clearance between the outer rotor 2 and the casing 1 is large, not only will the amount of leakage increase, but the outer rotor 2
The center Ot of the shaft oscillates, causing tooth contact, which further reduces mechanical efficiency and generates noise.

Therefore, it is conceivable to set the clearance between the outer rotor 2 and the casing l as small as possible, specifically to 0.05 mm or less. However, with this level of clearance, even if the finishing accuracy of the outer circumferential surface of the outer rotor 2 and the inner circumferential surface of the casing l is improved, the influence of friction between them cannot be ignored, and the problem arises that mechanical efficiency will be greatly reduced. there were.

This invention has been made to solve the above problems, and an object of the invention is to provide an internal oil motor that generates less noise and is more efficient.

"Means for Solving the Problems" The present invention has been made to solve the above problems, and includes a ring-shaped outer rotor loosely inserted into a cavity in a casing, and an outer rotor in the cavity. An inner rotor that is rotatable inside the rotor, and a tooth surface that is opened in the space toward the rotational direction of the inner rotor and formed on the inner circumferential surface of the outer rotor and the outer circumferential surface of the inner rotor. A suction port that supplies fluid to the space and a discharge port that opens into the void and discharges the fluid in the space are provided on the outer peripheral surface of the outer rotor and communicate with the suction port as the inner rotor rotates. It is designed to form a recess.

In terms of strength, it is preferable that the formation position of the recess corresponds to the position of the ridges on the tooth surface of the outer rotor.

The reduction ratio of the area of the sliding contact surface between the outer rotor and the casing due to the recess is set to 50% or more, more preferably 70% or more, and the radial clearance between the outer rotor and the casing is set to 0.05 mm or less, more preferably It is set to 0.04 mm or less.

[Function J] The space formed on the tooth surface between the inner rotor and outer rotor attempts to expand due to the pressure of the hydraulic oil supplied from the suction port, and as a result, the inner rotor and outer rotor rotate around their respective axes. Rotate. With this rotation, a recess formed on the outer peripheral surface of the outer rotor opens to the suction port and communicates with the suction port. The fluid in the suction port flows into the space, and its dynamic pressure also acts on the recess to impart rotational force to the outer rotor, resulting in an increase in the mechanical efficiency of the motor. Since the sliding contact area between the outer rotor and the inner rotor is reduced compared to the case where there is no recess, energy loss due to friction is significantly reduced. The hydraulic oil in the recess provides lubrication between the sliding surfaces, improving mechanical efficiency. Therefore, the radial clearance between the two at locations other than the recess can be set small, reducing the runout of the outer rotor, reducing the amount of leakage, and reducing noise.

"Embodiment" FIGS. 1 and 2 show an embodiment of the present invention, and the same components as the conventional example shown in FIGS. Omitted.

In the internal oil motor of this embodiment, recesses 7 are formed on the outer peripheral surface of the outer rotor 2 at equal intervals in the circumferential direction and penetrating both sides thereof.

This recess 7 is formed at a position corresponding to the peak of the tooth surface 2a of the outer rotor 2, and its shape is not axisymmetric with respect to the diameter passing through the top of the peak of the tooth surface. The front side in the rotational direction of the recess 7 is formed by being deeply cut from the outer circumferential surface, and as a result, the angle of inclination of the front surface of the recess 7 in the rotational direction is larger than that of the rear wall. The length of the recess 7 is set to be 70% or more of the pitch of the tooth surface in terms of center angle. The distance between the convex surface 8 located between the recess 7 and the inner circumferential surface lb of the casing 1, that is, the radial clearance, is set to 0.05 mm or less.

In the oil motor configured in this manner, when hydraulic oil is introduced from the suction port 5, a space S is formed between the tooth surfaces 2a and 3a of the inner rotor 3 and the outer rotor 2.
tries to expand due to the pressure of the hydraulic oil, and as a result, the inner rotor 3 and outer rotor 2 are aligned with their respective axes O.
Rotates around I, Ot. With this rotation, the recess 7 formed on the outer circumferential surface of the outer rotor 2 opens into the suction port 5.
It opens and communicates. The hydraulic oil in the suction port 5 flows into the space S as shown by the arrow in FIG. 1, and its dynamic pressure also acts on the recess 7 to impart rotational force to the outer rotor 2.
As a result, the mechanical efficiency of the motor is increased.

The oil motor of the embodiment and the comparative example include an oil motor having the same clearance and an outer rotor 2 without a recess, and an oil motor having the same recess 7 and a radial clearance of 0.
Create an oil motor with a diameter of 0.06 mm,
The machine was operated under the same conditions and mechanical efficiency and noise were measured.

The conditions were to use normal hydraulic oil as the working fluid and a hydraulic pressure of 5.
0 kg/cm”, oil temperature 80℃, rotation speed 200Or
It was set as pm.

As shown in the results in FIGS. 3 and 4, in the conventional case without recesses, the mechanical efficiency significantly decreases when the radial clearance decreases from 0.07 mm to 0.06 mm or less. On the other hand, the example of the present invention has a clearance of 0.04 mm or less and has a mechanical efficiency that is about 9 to 10% higher than that of the comparative example. Further, the noise characteristics of the examples clearly show that the frequency distribution is narrow, the total amount of wasted energy spent on noise is small, and there is particularly little harsh high-frequency noise.

In this embodiment, the recess 7 is located between the tooth surfaces 2a and 3a.
Since the outer rotor 2 is made to correspond to the position of the peak, the thickness in the radial direction of the outer rotor 2 is ensured, and a decrease in strength is prevented.

In the embodiments described above, the pitch of the recesses 7 is set to be the same as the pitch of the tooth surface, but it can be set as appropriate depending on conditions such as clearance.

Further, the cross-sectional shape of the recess 7 or the shape viewed from the outer circumferential side is not limited to the above embodiment.

[Effects of the Invention] As explained above, according to the present invention, the dynamic pressure of the fluid flowing into the space from the suction port acts on the recess and imparts rotational force to the outer rotor, resulting in an increase in the motor speed. Increase machine efficiency. Furthermore, the sliding contact area between the outer rotor and the inner rotor is reduced compared to the case without a recess, and
Since the hydraulic oil in the recess acts as a lubricant between the sliding surfaces, friction is reduced and mechanical efficiency is improved. Therefore, for example, in a low-torque, high-rpm motor, etc., the radial clearance can be reduced without reducing mechanical efficiency, and the excellent effect of reducing the amount of noise can be achieved.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, with Figure 1 being a sectional view of an oil motor, Figure 2 being an enlarged perspective view of its main parts, and Figure 3 showing mechanical efficiency. Graph, Figure 4 is a graph showing noise characteristics, Figures 5 and 6 are examples of conventional oil motors, Figure 5 is a front sectional view of the oil motor, and Figure 6 is a side sectional view. It is. 1...Casing, 1a...Vacancy, 2...
・Outer rotor, 3... Inner rotor, 2
a, 3a...Tooth surface, 5...Suction port, 6
...Discharge port, 7...Recess, S...
···space.

Claims (1)

[Claims] A ring-shaped outer rotor is loosely inserted into a space in the casing, an inner rotor is rotatably provided inside the outer rotor in the space, and a ring-shaped outer rotor is inserted into the space in the direction of rotation of the inner rotor. a suction port that opens to supply fluid to a space between the tooth surfaces formed on the inner circumferential surface of the outer rotor and the outer circumferential surface of the inner rotor; and a suction port that opens to the void and discharges the fluid in the space. An internal oil motor comprising: a discharge port, and a recess is formed in the outer peripheral surface of the outer rotor to communicate with the suction port as the inner rotor rotates.