JPS6224057A - Gear shift mechanism for two gear driving systems - Google Patents

Abstract

PURPOSE:To simplify a gear shift mechanism by providing a difference in level between gears to be shifted. CONSTITUTION:In case of shifting gears of the same array order in two gear trains of a feed driving system, a pair of gears 8, 9 to be shifted are arranged in such a manner that one of the gears has an axial difference in level with respect to the other gear thereof, seen from the lateral direction. Further, there is provided a shift mechanism 12 for shifting the gears 8, 9 at the same time. This arrangement can simplify the mechanism of shifting the gears.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a feed drive system of a numerically controlled machine tool, in which two gears are meshed with a driven gear provided to eliminate backlash.
Arrangement 11 in two systems of gear trains
This invention relates to a gear shift mechanism for cutting off or connecting power transmission by shifting a pair of gears that are in the same position.

(Background technology and its problems) Conventionally, in order to avoid P7 crash in a numerically controlled feed drive system, two gear trains were branched from one motor.
Two pinions are simultaneously engaged with gears or ring gears fixed to a table or bed, and one ring gear in the gear train has a wind-up function.

In particular, numerically controlled vertical lathes have a main drive system equipped with a turning drive gear train that is separate from the table indexing feed system of the numerically controlled feed drive system mentioned above, and in milling mode, the table indexing feed system is In turning mode, the ring gear is connected to the main drive system.

Therefore, when the table indexing feed system is not used, the gear train between the ring gear and the servo motor must be disconnected.

At this time, in order to minimize the load inertia applied to the main drive system, it is necessary to disconnect at a point close to the ring gear, so it is necessary to disconnect two corresponding gears from the two gear trains mentioned above at the same time. Conversely, when transmitting power, it is necessary to shift and engage the gears at the same time.

Conventionally, the applicant previously disclosed a technique for meshing two systems of gear trains in Japanese Utility Model Publication No. 51-25660, but the mechanism was complicated, which caused problems.

[Purpose of the invention]

An object of the present invention is to provide a feed system in which a table gear has two systems, a main drive system and a numerically controlled feed system, such as a numerically controlled vertical lathe, and to provide gear shift 14fQ in the feed system.
The goal is to provide a structure.

[Means and actions for solving the problem] When meshing one system of gear trains, whether or not the shift gear can shift properly is determined by the tooth position in Figure 1A, which shows a cross section of the shift gear on the pitch. When the teeth and mouth are about to engage, the coefficient of friction is μ, and the angle between the point of contact between the teeth and the mouth and the center line of the mouth is θ.If θ>tan−'μ, then shift is possible, θ< If j a n-'μ, it becomes impossible to shift.

Here, the radius of the tip of each tooth 41 is R, and the angle θ at the limit where the tooth and the mouth can mesh is θ. Then, θ. -t a n-'μ, and the distance between both teeth δ in this meshing limit state. is δ. =2Rs in θ.

becomes. Further, the shape of the tip of each tooth 42 is conical, as shown in FIG. 1B, to facilitate meshing.

However, in a two-system gear train, the following four cases are possible.

■Both can be soft and interlock.

■One side is shiftable and the other is not, so they do not mesh.

■Both cannot be shifted and do not mesh.

■They can be shifted together, but they eat.

(2) to (2) are simple combinations of one system, and in terms of phenomena, (2) can be considered to be shiftable, while (2) and (2) cannot be shifted, but (2) will be explained with reference to FIGS. 2A to 2D. In the two systems of gear trains A and B, when the combination of regular 4 meshing states is in the state shown in Figure 2A, If the distance between both teeth when each tooth 41 contacts at an arbitrary angle position is δ1.δ8, then δ4, δ8 > δ.On the other hand, ■ “Both can be shifted but bite” means In the state shown in Figure 2B, each combination is δ4
, δ8 〉δ. In other words, since θ>tan-'μ, it is possible to shift, but both gears are cut, and each tooth 4 in B
Since the positional relationship with the two ports is not the normal engagement position, it will go in to a certain point and then stop. At this time, if it is pushed in due to the wedge effect, it will not come out even if you try to pull it out, resulting in a "sticking phenomenon".

At this time, if the hacklash of the two gear trains A and B is small, when they are not in the regular meshing position as shown in Figure 2B, δ
4, δ8kuδ. Both become impossible to shift, but if a hydraulic oscillation device is incorporated, hacking and lashing will increase, which may result in problem (2).

When considering gear cutting as a standard, the phase of gear train B can move within a range of ±δ due to the total backlash of the gear train (including play that occurs within the hydraulic oscillation device), so δ〉 δ.

In this case, the situation ■ may occur. Therefore, by adding steps to the shift gears of gear trains A and B, gear train A'tJ<
If gear train B is shifted to a certain degree of engagement and then shifted to the meshing position, gear train B can move within the range of δ3 ±δ if float train A has shifted to δ8. In Fig. 2C, the limit distance between both teeth δ that allows teeth to mesh on the opposite side of the normal meshing position of the tooth opening and the actual distance between both teeth δ. If the moving bone δ is small, that is, δ, +
δ. 〉δ, or in other words, δ8〉δ−δ. If so, gear train B will be unable to shift even if it deviates from the normal meshing position, so it will not be able to shift to the point where it engages. This can be achieved by providing a step between the shift gears of gear trains A and B. In other words, if there is no step, both shift gears will mesh at the same time without considering the position of the shift gear in gear train B relative to the shift gear in the gear train, resulting in jamming, but if a step is provided, the gears will jam. Since the shift gears of gear train B can be meshed while the shift gears of gear train B are in a meshed state, gear train A is meshed so that the shift gears of gear train B are meshed under the condition that the above-mentioned jamming does not occur. This is because the shift of gear train B can be repeated without any change.

Therefore, similarly to the shift of one gear train, ■ or ■, ■
In other words, there are only two phenomena: whether it is possible to shift or not.

From this, the present invention provides at least one gear train of a feed drive system that transmits power from one drive source to two pinions meshing with a driven gear through separate gear trains.
A gear having a transmission mechanism in which two or more gears are ring-shaped gears, a plurality of variable capacity oil chambers are configured in the ring-shaped gears, and driving torque is transmitted from the ring-shaped gears to the gear shaft via the oil chambers. In the drive system, when shifting the gears having the same arrangement order in the two gear trains of the feed drive system, the pair of gears to be shifted are, when viewed from the lateral direction,
It is characterized in that one gear is provided so as to have a step in the axial direction with respect to the other gear, and a shift a mechanism is provided for shifting the gears simultaneously.

〔Example〕

The third is a schematic side view of the table indexing and feeding system in a numerically controlled vertical lathe.

1 is a driven gear fitted to a processing table; ring gears 2 and 3 are pinions meshed with ring gear l; 4,
5 is a gear shaft fixed to pinions 2 and 3, respectively, 6 and 7
are spur gears fixed to the gear shaft 4.5, and spur gears 8 and 9 mesh with the spur gears 6 and 7, respectively.These spur gears 8.9 are supported by the support plate 13, and are connected to the piston of the hydraulic cylinder 12. An axial shift is possible in each case with respect to the gear shaft 10.11 by means of the rods 12a.

14.15 is a spur gear fixed to the end of the gear shaft 10.11, and the spur gears 1.6.17 mesh with the spur gear 14.15, respectively. Spur gear 16.17 is spur gear shaft 18.19
A gear 20 is fixed to one end of the gear shaft 18, and a gear 20 is fixed to the other end of the gear shaft 18. The other end of the gear shaft 19 is provided with a rocking device (preload device) shown in FIG.

In FIG. 4, there are three partition plates 3 on the outside of the gear shaft 19.
A cylindrical rotor 30 provided with a diameter 0a is fixed via a key, and a cylindrical part is provided inside the ring-shaped (including cylindrical) gear 21 so as to be relatively movable in contact with the partition plate 30a. A partition plate lea is provided inside the cylindrical portion. The upper and lower surfaces of the rotor 30 and the ring gear 21 are sealed with lids, and pressure oil is supplied through an oil passage 32 bored in the center of the gear shaft 19 and an oil passage 33 bored in the radial direction. Oil chambers A, B, and C constituted by 30a, 21a and the upper and lower lids are filled with pressure oil.

In FIG. 3, spur gear 22 is a spur gear that meshes with both spur gear 20 and ring-shaped gear 21. In FIG.

One end of the gear shaft 23 is fixed to the gear 22, and the other end is fixed to the bevel gear 2.
It is fixed at 4. Furthermore, the bevel gear 24 is a bevel gear 25 fixed to the output shaft 26 of a servo motor 27 as a drive source.
It meshes with.

Therefore, when the motor 27 is driven to rotate, the bevel gear 25
．． The gear 22 is rotated through the ring gear 21 and the gear 17 . +5.9°7, rotates pinion 3, and the other gear 20°16.14, 8, 6, drives pinion 2. The gear 2 is rotated by the swinging mechanism shown in FIG.
1.1.7.15.9,7, pinion 3, ring gear 1
, pinion 2, gears 4, 6, 8.15.16.20.2
Since the loop 2 is preloaded, the ring gear 1 can be driven to rotate without backlash except between the bevel gears 24 and 25.

An enlarged sectional view of the shiftable spur gears 8 and 9 is shown in FIG. As is clear from the figure, m i 8 .

Comparing the upper surfaces of the gears 9, the level difference H fair float 8 is higher than the spur gear 9. In order to shift and mesh the spur gears 8.9, first, the oil chambers A, B,
Cut off the supply of pressure oil at C and release the preload between the gears. Next, the hydraulic cylinder 12 is actuated to pull in and extend the rod 12a, which is repeated several times until the gear 8 meshes with the gear 6. When the gear 8 meshes with the gear 6, the other gears interlock and move slightly to engage the gear 9. Since the meshing conditions of the gears 7 are satisfied, each of the gears 9 can mesh with the gears 7. Conversely, when the gear 8.9 is disengaged from the gear 6.7, the hydraulic cylinder 12 can be operated by simply releasing the pressure oil in the oil chambers A, B, and C in the ring gear 21. Bye. When using this indexing drive system, oil chamber A,
Backlash can be eliminated by supplying pressure oil to B and C again.

In addition, the symbols 10A and lIA in FIG. 5 are gear shafts 1, respectively.
This is a spline formed at 0,1.1.

Further, whether the gear 8.9 is shifted to the normal position is checked by the lower limit detection limit switch 53 and the upper limit detection limit switch 54, and upon receiving this confirmation signal, the motor 27 is activated. Ru.

In the above embodiments, a ring gear is used as the driven gear, but the present invention is not limited thereto, and a rack, a spur gear, etc. may be used.

〔Effect of the invention〕

As mentioned above, in a table indexing feed system such as a numerically controlled vertical lathe, two drive systems are connected from one motor.
When a pair of gears with the same arrangement order in the gear train of the two systems are simultaneously shifted to engage and disengage, the gear shift mechanism can be simplified by providing a step between the gears being shifted. , and can perform reliable gear shifts.

[Brief explanation of drawings]

Fig. 1A is a cross-sectional view taken along line IA-IA in Fig. 1B, showing the meshing state in one system of gear trains, and Fig. 1B is a perspective view showing the tooth profile of a part of the gear train. , Fig. 2C is a cross-sectional view showing the meshing state of the two gear trains, Fig. 3 is a developed view showing the gear train of the indexing and feeding system of the table, and Fig. 4 is a horizontal cross-sectional view of the ring-shaped gear. FIG. 5 is an enlarged sectional view of the vicinity of the spur gear 8.9. ■...Ring gear as driven gear, 2, 3...
Pinion, 8, 9... spur gear, IOA, IIA...
Spline, 12... Hydraulic cylinder, 12a... Rod, 13... Support plate, 21... Ring-shaped gear, A. B, C...oil room, H...step. Agent Patent Attorney Minoru Kinoshita Figure 1A Figure 1B Figure 2B Figure 2C Figure 3 Figure 4

Claims (1)

[Claims] (1) At least one gear in a gear train of a feed drive system that transmits power from one drive source to two pinions meshing with a driven gear through separate gear trains is a ring-shaped gear, and the ring A gear drive system comprising a plurality of variable capacity oil chambers formed by a plurality of partition plates in a ring-shaped gear, and a transmission mechanism that transmits driving torque from the ring-shaped gear to the gear shaft via the oil chamber. When shifting a pair of gears that are arranged in the same order in the two gear trains of the feed drive system, the pair of gears to be shifted have a step difference in the axial direction with respect to the other gear when viewed from the lateral direction. What is claimed is: 1. A gear shift mechanism for a two-series gear drive system, characterized in that a shift mechanism is provided to simultaneously shift the same gears.