JPS59151666A - Power transmission mechanism having pinion and rack - Google Patents

Abstract

PURPOSE:To prevent the pi (pi) from entering in the feed amount of a rack so that the difficulty in selecting the number of teeth is eliminated, by setting the moving amount of the rack corresponding to one tooth pitch rotation of a pinion, and as well by forming a rack with a pressure angle corresponding to the afore-mentioned moving amount. CONSTITUTION:A rack tooth surface (ab) which is meshed with an involute curve (aAc) having a base circle (Dg) moves, when the curve (aAc) rotates in the direction E and reaches a curve (a''b'B'), to a rack tooth surface (a''b'B') in the direction F which corresponds to the movement of the curve (aAc). By estimating that the involute curves (aAc), (a''b'B') are the adjacent tooth shapes of a pinion of standard gear type, the moving distance of the rack changes as such bb', BB' when the pinion gear rotates by one tooth pitch, and therefore, the moving distance may have an arbitrary value by changing the pressure angle of the meshed rack tooth surfaces. With this arrangement the pressure angle is changed while the normal pitch of the rack is maintained, and, as a result, the meshed pitch circle diameter of the pinion is changed to prevent the affection of pi (pi).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transmission mechanism in which pi is not included in the rack feed amount in a rank and binion assembly mechanism.

For example, in the control system VCs for the feeding mechanism of tables, etc. of numerically controlled machine tools, a combination of a servo motor with a detector and a ball screw is often used, and in this case, the amount of movement of the table, etc. per one rotation of the motor is usually The drive by this ball screw is 0, which is equal to the lead of the hole screw.
The rack and pinion are mechanical elements that are widely used as one of the mutual conversion mechanisms between rotational motion and linear motion.
Looking back, the amount of rack movement per revolution of the standard gear, the binion, includes pi, 1'f1. ""c reed. Since this pi is an infinite decimal, it is not possible to accurately determine the amount of movement of the rank relative to the binion, and it is necessary to remove the influence of this pi.

Figure 1 shows a motor with a gear reducer and a rack.
, b, c, d, e, f-g, and drive motor 1
Suppose that the rack 2 is fed by the rotation number 9 and the lid 2L is the following formula.

Here, m is the module of the hex & g gear, and π is calculated by the pi ratio. A selection must be made so that the effects of the final rCπ can be approximately eliminated by combining the numbers a-f to give l/x, but this selection is not easy.

Further, Fig. 2 shows an example in which the rotation of the motor 1 is reduced to an integer ratio by the worm reducer 3 to drive the binion 4, but in this case as well, the rack 2 and the binion 4 are connected by a normal module system. If this is used, the feed iK of the rack 2 per revolution of the motor l will include the value of π. In this case, it is also not easy to eliminate π.

Furthermore, other pi removal force methods include: ■ Using a helical gear and a helical rank 2 ■ Using a spur gear and a rank of a circumferential pitch system ■ Using a spur gear of any module and a rank 2, etc. There are various methods, but for (2), τ generates a component force in the direction of the oak during driving depending on the helix angle, so countermeasures are required.As for (3), this system is not currently used in Japan. ) has drawbacks such as the extremely difficult production of binions.

Therefore, in view of the above-mentioned drawbacks, the present invention attempts to eliminate the difficulty in selecting the number of teeth that is necessary when a drive mechanism using a rack and binion is adopted in a numerical control system, and also to simplify the mechanism and structure. There is a particular thing.

The present invention that achieves the purpose of Katajima is based on a power transmission mechanism consisting of a combination of a pinion and a rack.
The amount of movement of the rack when the binion rotates by one rotation is set as an integer or a finite decimal number, and the rack is formed at a pressure angle corresponding to the amount of movement as a percentage.

Products to which this new idea can be applied include (↓ Products with drive mechanisms such that the amount of rack feed per rotation of the binion is n, such as large-scale machining machines.

1) A product with a transmission mechanism in which the binion rotates by one rotation corresponding to the strain rate for a given feed amount of the rack, for example, a product with a device that detects the feed amount of a table etc. as a (ro) rotation angle. There are products that have a mechanism that allows the relationship between the rotation angle and the horizontal direction of the rack to be changed during use.An embodiment of the present invention will now be described with reference to FIG. Third
The figure is a clear diagram for removing the pi of the binion. Third
Fig. 1. Involute piece W with basic circle as Dg;
4 The rack tooth surface ab that meshes with aAc rotates in the direction of the involute curved axis or arrow E and bends! When moving to a'b'B', the rack tooth ia'b"! moves in the direction of the arrow F corresponding to this movement. In this case, the rack-surface feed #) ikπ" is the rack tooth surface If the meshing pressure angle is α, and the starting point a of the engine is the distance π along the base circle Dgt/C (=ab), then the following equation is obtained.

Regarding the other rack tooth surfaces AB and n that mesh with each other at a pressure angle α°, the feed mass production 1 of 7 tooth surfaces is given by the following equation.

'AB BB /C08(2'...(2
] Based on this, even if the pressure angle changes due to the nature of the involute curve for a single basic circle l) gK, the relationship Ω1 = 91 = eave 1, that is, tn = t'n, exists. 21 Therefore, the following formula holds true: O BB' = ab'/. osa'...
(3) As a result, (IJ (from equation 33, the following equation is obtained.

If the axes aAc and abB are the adjacent tooth profiles of a standard gear (binion), the amount of movement of the rack when the gear rotates by one tooth is not constant, but is as follows: fibb, t3B By changing the meshing pressure angle, the amount of movement can be set to any value within a range that is not limited by the number of teeth simultaneously meshing or the strength of the rack.
1! It is possible to obtain a total of 9 a (This means that when the normal meshing pitch circle of the binion is, for example, PCI, other arbitrary pitch circles PC, D can also be used as the meshing pitch circle. ing.

As a result, due to the change in the movement m-i due to the change in the pressure angle, the movement amount (feed amount) K can be easily removed from π, which was included in the conventional method. Therefore, the tooth surface of the rack may be formed with a pressure angle excluding π.

In this way, even if an inexpensive commercially available worm speed machine as shown in FIG. 2 is used, the influence of π can be easily removed by appropriately determining the rack 2 teeth that mesh with the pinion 4, and the machine can be made small and inexpensive. Note that other appropriate gear devices may be installed in the worm reducer portion depending on the application, and the pinion can be directly connected to the motor depending on the anastomosis.

, In addition, there is a device Kj5- which must detect the amount of movement of the rack in units of sound number (u M of rotation) (71) as one rotational speed, and as shown in FIG. If there was a configuration consisting of a, b, , c, d and a timing belt 5 with a gear ratio l:1, this T4La, b, c, d and a timing belt 5 (Teπ
However, since the influence of π can be eliminated by the rack, it is also possible to configure only one pinion 4ffi with the speed increasing ratio ti:2 of the timing belt 5, as shown in FIG.

In the configuration shown in FIG. 6 in which the rack 2 is attached to the base 6 so as to slightly rotate around the pin 7 as a fulcrum, the meshing pressure angle β increases or decreases by Δβ, so the rotation of the pinion In Fig. 6, only the fifth side of rank 20 can be changed, and the right side 1 is fixed to the base (not shown in the rack 2). We are working on the assumption that there will be four 1Ili units, but if we give an excessive amount of back rack and top clearance, it will be possible to reduce the pressure angle to rank 2, which can be adjusted symmetrically to the right side of the tooth.

As explained above, according to the present defense, the standard sono-kuma and the pinion are used, and the pressure angle is changed while maintaining the locking pinion of the mating rank, and as a result, the anastomotic pitch circle diameter of the pinion is changed. By this, it is possible to obtain an arbitrary feed amount within a certain range, which eliminates the influence of pi, and by eliminating the difficulty in selecting the number of teeth, it is possible to simplify the mechanism and structure.

[Brief explanation of drawings]

Figs. 1 and 2 are perspective views showing two examples of conventional power transmission mechanisms for explanation, Fig. 3 is an explanatory view showing the principle of the present invention, and Figs. FIG. 6 is a perspective view of the force transmitting device, and is a configuration diagram in which changes in the pressure angle of the rack can be effectively utilized. In the drawing, l is a motor, la is a detector, 2 is a rack, and 4 is a binion. Figure 31 O Figure 4 Iθ

Claims (1)

[Claims] 1 created by combining with the binion track
In the power transmission mechanism, the amount of movement of the rack when the pinion rotates by one tooth is set as an integer or a finite decimal number, and the rack is formed at a pressure angle corresponding to the amount of movement. A power transmission mechanism with a rack.