JP2901502B2 - Design method of oscillating internal meshing planetary gear pair - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for designing a pair of oscillating internal meshing planetary gears, and more particularly, to a method of imparting a predetermined resistance to internal meshing between an internal gear member and an external gear member. The present invention relates to a method of designing an oscillating internally meshing planetary gear pair configured to obtain a brake torque against rotation by an external force.

[0002]

2. Description of the Related Art Conventionally, hydraulic motors such as those shown in FIGS. 6 to 8 have been proposed. This hydraulic motor mainly includes a casing 10, an internal tooth member 20, an external tooth member 30, a drive member 40, an output shaft 50, a volume chamber 60, and a pressure oil supply means 70.

[0003] The internal tooth member 20 includes a roller 21 corresponding to internal teeth.
The casing 10 (via the stationary valve member 74).
Fixed. The external tooth member 30 is provided with a number of external teeth 31 smaller by one than the number of the rollers (internal teeth) 21, and the axial center thereof is eccentric from the axial center O of the internal tooth member 20 by a predetermined amount e. It is assembled so as to be inscribedly engaged with 20. The external tooth member 30 has an internal spline 32 at the center.

The drive member 40 has convex outer splines 41 and 42 at both ends, and the outer spline 41 is
0 with the inner spline 32. Output shaft 50
Includes an inner spline 51 that meshes with the outer spline 42 of the drive member 40. The output shaft 50 is connected to the rotating case 53 via a spline 52.

[0005] As shown in FIG. 7, a plurality of volume chambers 60 are formed between the internal tooth member 20 and the external tooth member 30.
Pressure oil is selectively supplied to the volume chamber 60 by the pressure oil supply means 70 in synchronization with the rotation of the external tooth member 30.

In this conventional example, the pressure oil supply means 7
0 is a counter balance valve 73, a stationary valve member 74,
It mainly comprises a rotary valve member 75 and a number of oil passages formed between these members. The specific configuration has already been disclosed in detail, for example, in Japanese Utility Model Laid-Open No. 3-99874. The description is omitted because it has no direct relation to the gist of the present invention. In FIG. 8, reference numeral 98 denotes a pump, and 99 denotes a switching valve.

Next, the operation of the hydraulic motor will be briefly described.

The pressure oil generated by the hydraulic pump 98 passes through predetermined oil passages formed in the counterbalance valve 73, the stationary valve member 74, and the rotary valve member 75 by switching of the switching valve 99, and the internal gears thereof. Member 20 and external tooth member 30
Is selectively supplied to a part of the volume chamber 60. As a result, the external teeth member 30 rotates in a direction in which the volume of the volume chamber 60 to which the pressurized oil is supplied increases. The selective supply of the pressure oil is performed in synchronization with the rotation of the external tooth member 30 by the functions of the stationary valve member 74 and the rotary valve member 75. As a result, the external tooth member 30 It continuously rotates inscribed in the same direction.

Since the number of teeth of the external teeth 31 of the external tooth member 30 is one less than the number of teeth of the roller (internal teeth) 21 of the internal tooth member 20, the external tooth member 30 moves around the axis O once. Each time it revolves, it shifts (rotates) by one tooth with respect to the internal tooth member 20 (set in a fixed state). The combined movement of the revolution and rotation of the external tooth member 30 is caused by the engagement of the internal spline 32 of the external tooth member 30 and the convex external spline 41 of the drive member 40, whereby the revolution component is absorbed and only the rotation component is extracted. Then, it is transmitted to the output shaft 50 via the outer spline 42 and the inner spline 51. Output shaft 5
Since 0 is connected to the rotating case 53 via the spline 52, the rotating case 53 eventually rotates at the same rotation speed as the rotation component, and can take out a very strong torque.

The hydraulic motor is provided with the volume chamber 6.
In order to form 0, an end plate 80 for closing the ends is provided at axial ends (right ends in FIG. 6) of the internal tooth member 20 and the external tooth member 30.

The external tooth member 30 and the internal tooth member 2
Numeral 0 constitutes the above-mentioned oscillating internal meshing planetary gear pair. Generally, this planetary gear pair has one member having a circular tooth shape (such as the roller 21) and the other member having a tooth shape. Has a contour that is considered to have been cut using the circular tooth profile. In a planetary gear pair used for a normal hydraulic motor or the like, there is a gap of several tens of μm between the external tooth member 30 and the internal tooth member 20, and even if the force is not as large as the hydraulic pressure, it is relatively small. It rotates smoothly even with external force.

On the other hand, in order to prevent a motor or the like from rotating by an external force in a neutral state where no hydraulic pressure is applied, a predetermined resistance is applied to the internal meshing of the planetary gear pair. A hydraulic motor having a so-called self-brake mechanism has been proposed.

In general, a planetary gear pair having a self-brake mechanism of this kind is provided with a predetermined diameter by increasing the external tooth member of a normal planetary gear pair in the radial direction without changing the tooth profile. The resistance is applied.

In other words, when cutting or polishing the tooth surfaces of the external teeth of the external tooth member, the amount of cutting or polishing is made smaller than usual without changing the basic tooth profile, so that the external tooth member can be cut. The outer shape is enlarged. Then, since the internal tooth member 20 is heated and thermally expanded, the external tooth member 30 and the internal tooth member 20 are assembled and the frictional force is generated in the tangential direction of the contact point (since the internal tooth member 20 cannot be assembled as it is). A brake mechanism is implemented.

[0015]

However, when the self-braking mechanism is realized in this manner, it is true that the braking torque proportional to the amount of interference between the external teeth of the external teeth member and the internal teeth of the internal teeth member. You can get
Since the interference amount itself varies depending on the meshing position relationship, there is a problem that the brake torque generated between the internal teeth of the internal gear member and the external teeth of the external gear member also fluctuates greatly depending on the meshing position.

[0016] Therefore, it is difficult to obtain a stable (constant) self-braking torque at the time of neutral operation, and when an attempt is made to guarantee a predetermined brake torque value that does not rotate reliably with respect to a predetermined external force, a specific engagement position is required. However, there is a problem in that an excessively large brake torque is generated, and energy loss during normal operation is correspondingly generated.

Further, since the brake torque varies depending on the meshing position, there is also a problem that the output torque obtained during normal operation naturally fluctuates greatly with a change in the rotational position.

The present invention has been made in view of such a conventional problem, and it is possible to always obtain a predetermined brake torque even if the meshing position changes, and therefore, the internal meshing of the planetary gear pair can be achieved. To minimize the rotational resistance during normal operation and minimize output fluctuations (with self-brake mechanism). It aims to provide a way to design pairs.

[0019]

According to a first aspect of the present invention, there is provided an external tooth member having n external teeth and an internal tooth member having n + 1 internal teeth meshing with the external tooth member. The axial center of the external tooth member is mounted eccentrically from the axial center of the internal tooth member by a predetermined amount, and the external tooth member revolves around the axial center of the internal tooth member while rotating by the internal engagement. The method for designing a pair of oscillating internal meshing planetary gears configured to obtain a braking torque against rotation by an external force by moving and applying a predetermined resistance to the internal meshing, wherein the external teeth and the internal teeth And the center position of one of the external tooth member or the internal tooth member is set to the other center position so that the sum of the calculated reaction forces at each contact point becomes substantially zero. And the center position And the procedure for determining the brake torque after moving, and rotating either one of the external tooth member or the internal tooth member relative to the other by an arbitrary angle, and repeating the above procedure to obtain the brake torque at a plurality of rotational positions. Obtaining, and a step of repeatedly changing the shape of at least one of the external teeth of the external tooth member and the internal teeth of the internal tooth member such that the deviation of the brake torque obtained at the plurality of rotational positions becomes substantially zero. , The above problem has been solved.

[0020] In the last term of claim 1, "if the deviation of a plurality of obtained brake torques becomes almost zero, the value of the brake torque becomes the target value of the brake torque. If the pitch circle diameter of at least one of the external gear member and the internal gear member is repeatedly changed, it is possible to design a planetary gear pair capable of obtaining a desired value of brake torque regardless of the meshing position. 2).

[0021]

In a planetary gear pair in which an external tooth member having an arbitrary tooth profile having n external teeth and an internal tooth member having an arbitrary tooth profile having n + 1 internal teeth are internally engaged. When the pitch circle diameter of the tooth member is larger than n / (n + 1) times the pitch circle diameter of the internal tooth member, the external teeth of the external tooth member and the internal teeth of the internal tooth member interfere with each other at a location of n + 1 or less and friction occurs. Force is generated.

In the present invention, the tooth shape of the external tooth member (or the internal tooth member) is adjusted by the following method so that the braking torque is always constant at an arbitrary meshing position between the external tooth member and the internal tooth member. Designed with

1) Obtain a reaction force (vector amount) at each contact point between the external teeth and the internal teeth: This reaction force is, for example, the amount of interference between the internal teeth and the external teeth at each contact point, and the shape of the contact point ( The curvature is calculated using the Lundberg equation, the finite element method, or the like from the material and the like.

2) The center position of the external tooth member (internal tooth member) is moved so that the total of the reaction forces obtained in step 1 becomes substantially zero:
For this movement, for example, the resultant force of the reaction force obtained in 1 is obtained,
Opposite to the direction of the resultant force, an amount proportional to the magnitude of the resultant force is performed. More specifically, the re-calculation of the total reaction force after moving the center position in this manner is repeated several times, and as a result, it is confirmed that the resultant force is substantially zero. Determine the center position of.

3) Determining the brake torque after moving the center position: The brake torque is calculated, for example, by calculating the distance between each contact point after moving the center position and the instantaneous center of the external tooth member. The product is obtained by calculating the product of the reaction force at each contact point and the frictional force obtained from the friction coefficient, and calculating the sum thereof.

4) The external tooth member (internal tooth member) is rotated by an arbitrary angle, and the above procedure is repeated to obtain a brake torque at a plurality of rotational positions: the external tooth member (internal tooth member) is rotated by an arbitrary angle. The position of engagement with the internal tooth member (external tooth member) as the mating member is changed. Then, the above procedure is repeated to calculate (a plurality of) brake torques.

5) The tooth profile of the external tooth member (internal tooth member) is repeatedly changed so that the deviation of the plurality of obtained brake torques becomes substantially zero: the magnitude of the plurality of brake torques thus obtained The tooth profile of the external tooth member (internal tooth member) is changed so that the value becomes substantially constant (so that the deviation becomes substantially zero), and the above procedure is repeatedly calculated. As a result, when the deviation of the brake torque is substantially zero, the tooth profile of the external tooth member (internal tooth member) is always engaged with the internal tooth member (external tooth member) as the mating member, so that the brake torque is always at an arbitrary position. It corresponds to a fixed tooth profile.

As described in parentheses in the above description, the same operation can be achieved by moving the center of the internal tooth member instead of moving the center of the external tooth member in 2). can get.

The same effect can be obtained by rotating the internal tooth member instead of rotating the external tooth member in 4).

Further, in 5), instead of "changing the tooth profile of the external tooth member", "changing the tooth profile of the internal tooth member" is achieved. A similar effect can be obtained by changing the value (for example, about half).

If the brake torque obtained in this way does not match the target brake torque, the above procedure is repeated after changing the pitch circle diameter of the external tooth member or the internal tooth member so as to match. Thus, it is possible to obtain a planetary gear pair capable of generating a target brake torque at any rotation angle.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 shows a meshing state of the internal tooth member 120 and the external tooth member 130 to be designed by the designing method according to the present invention.

In the drawing, reference numeral 121 denotes an internal tooth member 120.
The rollers 131 correspond to the internal teeth of the external tooth member. The basic configuration of each member is not particularly different from the configuration of the hydraulic motor described as the conventional example.

In this embodiment, in order to obtain a self-braking mechanism, the external tooth member 130 is moved in a small amount (several tens μm) in the radial direction.
Only to be large. Therefore, since the external tooth member 130 and the internal tooth member 120 cannot be assembled in a normal state, the internal tooth member 120 is heated and thermally expanded to be mounted. As a result, the contact point between the roller (internal teeth) 121 of the internal tooth member 120 and the external teeth 131 of the external tooth member 130 is elastically deformed as shown in FIG. 4, and the external teeth 130 are rotated in this state. Then, a frictional force as shown by an arrow is generated at each contact point with respect to the instantaneous center O1, and this functions as a self-brake.

Hereinafter, a method of designing the external tooth member 130 with respect to the (fixed) internal tooth member 120 according to the control flow shown in FIGS. 1 and 2 will be described in detail.

In step 200, the target brake torque T to be obtained by the planetary gear pair (the internal gear member 120 and the external gear member 130) is input, and the diameter and the diameter of the roller 121 corresponding to the internal gear of the internal gear member 120 are input. A pitch circle and other various data are input.

In step 202, the provisional specifications of the external tooth member 130 are input, and the number of times N for calculating the brake torque Ti is input and set.

In step 204, the initial value of the number (the number of calculations) of the brake torque Ti is set to 1. The steps up to here are steps corresponding to input of so-called initial conditions.

In step 206, any combination angle θi
To place the external tooth member 130 at an arbitrary position.

In step 208, the amount of interference between the roller (internal teeth) 121 and the external teeth 131 at each contact point is calculated in this state. The “interference amount” is obtained as a pre-process for calculating the reaction force vector F at each contact point, and is defined as follows. That is, as described above, the roller (internal teeth) 121 of the internal tooth member 120 is used.
The external teeth 131 of the external tooth member 130 are in contact with each other while being elastically deformed as shown in FIG. 4A, but it is difficult to theoretically determine this state. As shown in (B), a state in which they are overlapped without deformation is considered, and the amount of overlap (maximum value) δ at this time is defined as “interference amount” in this embodiment. Since the meshing between the external tooth member 130 and the internal tooth member 120 is all performed by simulation on a computer, the interference amount δ is obtained by calculation once various dimensions of both members and the center position of the external tooth member are determined. be able to.

In step 210, the reaction force F at each contact point is calculated using Lundberg's equation as shown in the following equation.

[0043] δ = 1.3339 · Q / (E · l) × log {4.6930 · (l 3 · E / Q) · (R1 + R2) / (R1 · R2)} ... (1)

In the equation (1), Q is the contact load (reaction force), E is the Young's modulus, l is the thickness of the external tooth member 130, R1
Is the radius of curvature at the contact point of the external teeth of the external tooth member 130, R
2 is the radius of curvature of the roller 121 of the internal gear member 120.
Equation (1) is an equation that is satisfied when the external tooth member 130 and the internal tooth member 120 are of the same quality and the Poisson's ratio is 0.3.

When the interference amount is defined as a value as shown by b in FIG. 4A, the reaction force vector F is obtained by using, for example, Helz's equation as shown in equation (2). You can also.

B = 1.52√ [{(R1 · R2) / ｛E · (R1 · R2)} · P] (2) Here, P corresponds to a load (reaction force) per unit length.

In step 212, the sum ΣF of the reaction force vectors thus obtained is calculated. In step 214, it is determined whether or not the sum ΣF is substantially zero. Normally, the value does not become zero at one time, so the determination of NO is made, and the process proceeds to step 216 to move the center of the external tooth member 130 by an amount opposite to the direction of the sum of the reaction force vectors and in proportion to the magnitude thereof ( Reset), the total sum ΣF in step 214
Steps 208, 210 and 2 until it is determined that
12, 214, 216 are repeated.

When the sum ΣF of the reaction force vectors becomes substantially zero as a result of several trials and errors, step 2
Proceeding to 18, the distance between the instantaneous center O1 of the external tooth member 130 and each contact point is calculated, and the product of the reaction force of each contact point and the friction force obtained from the friction coefficient is calculated. Then, the frictional moment, that is, the self-brake torque Ti is calculated.

In step 220, it is determined whether or not the number (the number of calculations) i of the brake torque Ti thus obtained has reached the set number N. If it is determined that the number i has not yet reached N, the process proceeds to step 222. Then, i is incremented by one, and the routine returns to step 206 to calculate the brake torque Ti + 1 at a different combination angle θi + 1 according to the same procedure as described above.

When the N brake torques Ti have been obtained in this way, the flow proceeds to step 224 in FIG. 2, where the maximum value MAX (Ti) and the minimum value MIN (Ti) of the determined brake torque Ti are substantially equal. Is determined,
If they are not equal enough to be considered equal, step 2
Proceeding to 26, the tooth profile of the external tooth member 130 is changed, and the process returns to step 204. The procedure from step 204 is repeated based on the changed tooth profile of the external tooth member 130.

When it is determined in step 224 that the maximum value MAX (Ti) and the minimum value MIN (Ti) of the brake torque Ti are substantially equal, that is, the deviation of each of the i brake torques Ti becomes substantially zero. If it is determined that the brake torque has been reached, the routine proceeds to step 228, where it is determined whether the brake torque Ti is substantially equal to the target brake torque T. If they are not equal, the routine proceeds to step 230, and if the target brake torque T is smaller, it means that the calculated brake torque Ti is larger, that is, it interferes too much. In step 234, when it is determined that the obtained brake torque Ti is smaller than the target torque T, the pitch circle diameter of the external tooth member 130 is increased in step 234. To be larger. Then, the process returns to step 204, and the above-described flow is executed again. Then, when it is determined in step 228 that the obtained brake torque Ti is (substantially) equal to the target brake torque T, the control flow ends.

When the flow is completed as described above, the internal gear member 120 and the external gear member 130 at that time form a planetary gear pair in which a constant brake torque T is always obtained at an arbitrary meshing position.

FIGS. 5A and 5B show a comparison between the theoretical value of the conventional brake torque for each rotational phase and the theoretical value when the external gear is designed according to the present invention. As is apparent from the figure, a large change in the brake torque has conventionally been observed as the engagement position between the external tooth member 30 and the internal tooth member 20 shifts, but in the present invention, this change can be suppressed to a very small value. Became.

In the above embodiment, a plurality of brake torques are obtained by moving the center position of the external gear member and rotating the external gear, and a uniform brake torque is obtained by changing the tooth profile of the external gear. However, since the meshing between the external tooth member and the internal tooth member is in a relative relationship, instead of the above-described embodiment, the center position of the internal tooth member is moved, and It is of course possible to obtain N brake torques by rotation and obtain a uniform planetary gear pair by changing the tooth profile of the internal gear member. Further, regarding the change of the tooth profile, a configuration may be adopted in which both the internal tooth member and the external tooth member are changed at the same time, for example, about half each, instead of changing only one of them.

Similarly, it is not necessary to change the pitch circle diameter of only the external teeth member in order to match the target brake torque T. The pitch circle diameter of only the internal teeth member may be changed, or both pitch circles may be changed. The diameter may be changed.

[0056]

As described above, according to the present invention,
Since the fluctuation of the brake torque depending on the meshing position between the external tooth member and the internal tooth member can be reduced, a stable (constant) brake torque can be obtained even when both members are stopped at any phase angle. become able to.

Further, for example, when the external gear member or the internal gear member is activated as the planetary gear pair relating to the hydraulic motor, the variation in the activation pressure can be reduced.

Furthermore, since the fluctuation of the friction torque between the external tooth member and the internal tooth member during the normal operation can be reduced, an extremely stable output torque can be obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a first half of an embodiment of a method for designing a planetary gear pair according to the present invention.

FIG. 2 is a flowchart showing the latter half of FIG. 1;

FIG. 3 is a diagram showing a meshing state of an external tooth member and an internal tooth member.

FIG. 4 is an enlarged view of an arrow IV part in FIG. 3;

FIG. 5 is a diagram showing theoretical values of brake torque in comparison with a conventional example and this example.

FIG. 6 is an axial cross-sectional view showing a configuration of a hydraulic motor to which a conventional oscillating internally meshing planetary gear pair is assembled.

7 is a sectional view taken along the line VII-VII of FIG. 6;

FIG. 8 is a cross-sectional view partially including a hydraulic skeleton diagram along the line VIII-VIII in FIG. 6;

[Explanation of symbols]

 20, 220: Internal tooth member 21, 221: Roller (internal tooth) 30, 230: External tooth member 31, 231: External tooth e: Eccentric amount

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04C 2/10 321 F16H 1/32

Claims (2)

(57) [Claims] 1. An external tooth member having n external teeth and an internal tooth member having (n + 1) internal teeth meshed internally with the external tooth member, wherein the axial center of the external tooth member is the internal tooth The member is mounted eccentrically from the axial center of the member by a predetermined amount, and the external tooth member revolves around the axial center of the internal tooth member while rotating by the internal engagement, and a predetermined resistance to the internal engagement. in oscillating internally meshing a method of designing a planetary gear pairs configured to obtain the braking torque with respect to rotation due to the external force by applying a procedure for obtaining a reaction force at each contact point of the outer teeth and inner teeth, this A procedure of relatively moving the center position of either the external tooth member or the internal tooth member with respect to the other center position so that the sum of the obtained reaction forces at each contact point becomes substantially zero; To find the brake torque after moving If, one of the external gear member or the internal gear member are relatively arbitrary angular rotation relative to the other, a procedure for obtaining a brake torque at a plurality of rotational positions by repeating the above procedure, the rotational position of the plurality of Repetitively changing the shape of at least one of the external teeth of the external teeth member and the internal teeth of the internal teeth member so that the deviation of the obtained brake torque becomes substantially zero. How to design an internally meshing planetary gear pair. 2. An external tooth member having n external teeth, and an internal tooth member having (n + 1) internal teeth meshed with the external tooth member, wherein the axial center of the external tooth member is the internal tooth The member is mounted eccentrically from the axial center of the member by a predetermined amount, and the external tooth member revolves around the axial center of the internal tooth member while rotating by the internal engagement, and a predetermined resistance to the internal engagement. in oscillating internally meshing a method of designing a planetary gear pairs configured to obtain the braking torque with respect to rotation due to the external force by applying a procedure for obtaining a reaction force at each contact point of the outer teeth and inner teeth, this A procedure of relatively moving the center position of either the external tooth member or the internal tooth member with respect to the other center position so that the sum of the obtained reaction forces at each contact point becomes substantially zero; To find the brake torque after moving If, one of the external gear member or the internal gear member are relatively arbitrary angular rotation relative to the other, a procedure for obtaining a brake torque at a plurality of rotational positions by repeating the above procedure, the rotational position of the plurality of A procedure of repeatedly changing the shape of at least one of the external teeth of the external tooth member and the internal teeth of the internal tooth member so that the deviation of the obtained brake torque becomes substantially zero; And changing the pitch circle diameter of at least one of the external tooth member and the internal tooth member such that the value of the brake torque becomes substantially the target value of the brake torque, and repeating the above procedure. How to design a dynamic internal meshing planetary gear pair.