JPS63101546A - Switching mechanism of planetary speed change gear - Google Patents

Abstract

PURPOSE:To smoothly conduct switching operation by disposing a ball capable of freely idling either on a switching ring or a member engaged with the ring. CONSTITUTION:A planetary gear 2 having gear portions 21, 22 is engaged with a sun gear 1, and ring gears 31, 32 are disposed. A switch ring 7 is disposed on the outer periphery of the ring gears 31, 32, and a projection 70 is provided on the inner peripheral surface thereof. Balls 37, 38 are disposed in holes 35, 36 formed on the outer peripheries of the ring gears 31, 32, and engaging grooves 71 are provided in such a manner as to engage with the balls. Accordingly, there is no interference at the time of switching, so that smooth switching operation can be performed.

Description

[Detailed description of the invention] 【Technical field】

The present invention is directed to a planetary transmission for speed switching mainly used in power tools. It is related to the structure.

[Background technology]

As a planetary transmission, see Figure 18, Figure 11, or Figure 12.
The one shown in the figure has been used conventionally. What is shown in FIG. 8 is a gear part 21 with a large number of teeth and a gear part 22 with a small number of teeth in the "i star gear 2" which engages with the sun gear 1.
The gear part 21 is provided to mesh with the sun gear 1, and ring gears 31 and 32, which are concentric with the sun gear 1, are rotatably arranged around the outer periphery of each gear part 21 and 22, and the gear part 21
and the ring gear 31, and the gear part 22 and the ring gear 32 are meshed, so that both the ring gears 31, 3
By selectively disabling the rotation of the planetary gear 2, the gear ratio of the output appearing on the carrier 4 supporting the planetary gear 2 is changed. The ring gear 3 that meshes with the planetary gear 2 is rotatable and slidable in the axial direction.By sliding the ring gear 3 in the axial direction at k +-, the fixed gear 5 and the planetary gear 2 are supported. The gear portion 40 formed on the carrier 4 can be selectively engaged with the gear portion 40 . Here, the switching mechanism in the former is formed by forming a large number of grooves 33, 34 on the outer peripheral surfaces of both ring gears 31, 32, as shown in FIGS.
By sliding the switching lever 8 attached to the groove 33 of either ring gear 31 or 32,
．． 34 to prevent the rotation of the ring gear 31 or the ring gear 32. In the latter case, by sliding the ring gear 3 in the axial direction with the switching lever 8, the teeth in the ring gear 3 are Switching is performed by engaging the fixed gear 5 or the teeth of the gear portion 40 of the carrier 4. However, in the former case, for example, the illustrated ring gear 3
1 from the state where 1 is fixed with the switching lever 8. When trying to switch to a state where the other ring gear 32 is fixed,
Since the ring gear 32 is rotating, when the switching lever 8 enters the groove 34 of the ring gear 32, interference occurs between the two, which may cause abnormal noise or damage to the switching lever 8 or the ring gear. There is a risk of damage to parts 31 and 32. In the latter case, since interference occurs between the ring gear 3 and the fixed gear 5 or the gear portion 40 of the carrier 4 during switching, there are problems similar to those in the above case.
Since the teeth of ring gear 3 are used here, there is a risk that the teeth of ring gear 3 may be damaged.
This is a big problem.

[Purpose of the invention]

The present invention has been devised in view of these points, and its object is to provide a switching mechanism for a planetary transmission that can perform switching operations smoothly.

[Disclosure of the invention]

Therefore, the present invention provides a structure in which a plurality of members arranged in the axial direction among members constituting a planetary mechanism such as a ring gear or members provided in contact with a planetary gear are slidable at least in the axial direction. In a planetary transmission in which the gear ratio is switched by selectively engaging a switching ring,
One of the switching ring and the member that engages with the switching ring is characterized in that one side is provided with a freely rotatable ball, and the other side is provided with an engagement groove in which the ball engages, This is to prevent free rotation of the ball from interfering with the engagement groove. The present invention will be described in detail below based on the illustrated embodiments.
Figures 5 through 5 show an embodiment of the present invention. A sun gear 1 is attached to the output shaft of the motor 6, which is attached to a motor mount 12 that closes an opening at one end of the gear case 11. The sun gear 1 has two types of gear parts 21 and 22 with different numbers of teeth. Gear portions 21 of the integrally formed planetary gear 2 mesh with each other. And each gear part 2 of the planetary gear 2
Two ring gears 31 and 32 arranged concentrically with the sun gear 1 are arranged side by side in the axial direction on the outer periphery of 1.22. They mesh with the gears 32, respectively. A sun gear 41 is integrally formed on the carrier 4 that supports the planetary gear 2 by a support 46, and the output shaft 10
A planetary gear 42 supported by the sun gear 41 and a ring gear 43 rotatably disposed concentrically with the sun gear 41 mesh with each other. Ring gear 43 here
The rotation is regulated by the engagement of the ball 17 urged by the clutch bone 16 with the end face, and together with the clutch handle 15 and the cam plate 18, the tightening and torque adjustment part is configured. are doing. Now, the two ring gears 31 and 32 that are lined up in the axial direction have the same outer diameter, and on their outer peripheries there is a switching ring that does not rotate and is slidable in the axial direction. 7 is arranged. The switching ring 7, to which the switching lever 8 protruding from the outer surfaces of the gear case 11 and the housing 13 is attached, is provided with an annular protrusion 70 on its inner circumferential surface, and the protrusion 70 is provided with annular protrusions 70 at intervals in the circumferential direction. As shown in FIG. 2, a large number of locking grooves 71 in the axial direction are provided. Note that this locking groove 71 is connected to the protrusion 7
Both side walls have an axial taper of 0 and are open at both ends. On the other hand, holes 35 and 36 are formed on the outer circumferential surface of each ring gear 31 and 32 at intervals in the circumferential direction.
, 36 are provided with steel balls 37, 38 for free rotation, and some of these balls 37, 38 are connected to the ring gears 31, 3.
It protrudes from each outer peripheral surface of 2. Furthermore, these balls 37
．． 38 is prevented from being removed or dropped by the inner circumferential surface of the switching ring 7. As shown in FIGS. 1 and C/FIG. 2, when the switching ring 7 is in the rearward position, the ball 37 disposed on the ring gear 31 is engaged with the locking groove 71. Since the rotation of the ring gear 31 is prevented when the sun gear 1 is in the sun gear 1, the rotation of the motor 6 is determined by the number of teeth of the sun gear 1 and the ring gear 31. The gear ratio is transmitted to carrier 4, and at this time, ring gear 3
2 is idling. Conversely, by moving the switching ring 7 forward, as shown in FIGS. 3 and 4, the switching ring 7 is locked fi71.
When the ball 38 disposed on the ring gear 32 is engaged, the rotation of the ring gear 32 is prevented, so that the rotation of the motor 6 depends on the number of teeth of the sun gear 1 and the ring gear 32, as well as both gears of the planetary gear 2. The transmission is transmitted to the carrier 4 at a speed ratio determined by the number of teeth in the sections 21 and 22. By the way, the number of teeth on sun gear 1 is 2. ．． Assuming that the number of teeth of both gear parts 21 and 22 of the 11-star gear 2 is 221122□, and the number of teeth of both ring gears 31 and 32 is 231tZ8, the gear ratio from the carrier 1 to the carrier 4 is 1/. In the former case, in the latter case. The speed ratio up to the output shaft 10 is calculated by multiplying the above-mentioned speed ratio of both chambers by the value 1+243/241, which is expressed by the number of teeth of the sun gear 41, 241, and the number of teeth, 245, of 743 on the ring. is the sum of the two. Now, as is clear from the above, the switching ring 7
The gear ratio is switched by sliding the switching ring 7 and both ring gears 31, 32, and the selective connection and fixing of the switching ring 7 and both ring gears 31, 32 is performed by balls 37, 38. 38 is the projection 7 of the switching ring 7
Locking at 0? ll! The eJl& when entering 71 is smooth due to the rotation of the balls 37 and 38, and will not cause accidents such as abnormal noise or breakage due to interference, and will not engage with the locking groove 71. The balls 37 and 38 that do not match are connected to the switching ring 7 and the ring gear 31.
．． Since the ring gears 31 and 32 constitute a radial bearing and also perform centering, power loss due to the presence of the ring gears 31 and 32 that are not fixed by the switching ring 7 and rotate idly is reduced. Furthermore, the switching ring 7 can be slid freely due to the presence of the balls 37 and 38. As shown in Fig. 6 and WS7, the ring gear 31.3
Hole 35 formed in 2 and into which each ball 37, 38 is housed
．． A spring 39 may be provided within 36 which urges the balls 37, 38 outwards. In this case, the engagement groove 71 of the switching ring 7 and the ball 37.3
Since the spring 39 functions as a shock absorber against the impact when the two parts engage with each other, a smoother switching operation can be obtained. *In addition, the spring 39 here also functions as an overload protection clutch that causes the ring gears 31, 32 fixed by the switching ring 7 to idle when an overload occurs. In addition, here, we have shown an example applied to a planetary transmission equivalent to the conventional example shown in Fig. 8, but even if it is applied to a planetary transmission with a structure similar to the conventional example shown in Fig. , by forming the switching ring 7 integrally with the ring gear 3 and arranging a ball that engages with the fixed gear 5 and the carrying ring 7, it can be applied, and furthermore, it can be applied to other supplementary planetary transmissions. However, if the switching ring 7, which is slidable at least in the axial direction, selectively engages with some member due to its sliding, the gear ratio can be changed, then the above-mentioned member The present invention can be applied regardless of whether it is a component of a planetary mechanism such as a ring gear, a carrier, or a sun gear, or a fixed gear as in the case of the above-mentioned conventional example. Of course, the balls 37 and 38 may be provided on the switching ring 7 side.

【Effect of the invention】

As described above, in the present invention, the plurality of members that selectively engage with the switching ring when the switching ring slides in the axial direction are arranged such that the balls interposed between the switching ring and the switching ring engage with the engagement grooves. It is connected to the switching ring, and for this purpose,
There is almost no interference during switching, and smooth switching can be performed without causing any abnormal noise or damage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same, FIG. 3 is a vertical cross-sectional view of the same when switching, FIG. 4 is a cross-sectional view of the same, and FIG. is an exploded perspective view of the same as above, FIG. 6 is a vertical cross-sectional view of another embodiment, FIG. 7 is a cross-sectional view of the same as above, FIG. The cross-sectional view of the same as above, rtS11 is a vertical cross-sectional view of another conventional example,
FIG. 2 is a longitudinal sectional view of yet another conventional example, in which 7 is a switching ring, 31° and 32 are ring gears, 37 and 38 are balls,
71 indicates an engagement groove.

Claims (2)

[Claims] (1) A switching ring that is slidable at least in the axial direction is selected for a plurality of members arranged in the axial direction among the members constituting the planetary mechanism such as the ring gear or the members provided adjacent to the planetary mechanism. In a planetary transmission in which the gear ratio is switched by engaging the switching ring and the member that engages with the switching ring, a freely rotatable ball is disposed on one of the switching ring and a member that engages with the switching ring, and the ball is disposed on the other. 1. A switching mechanism for a planetary transmission, characterized in that it is provided with an engagement groove that engages. (2) The planetary transmission according to claim 1, wherein the ball disposed on one of the switching ring and the member that engages with the switching ring is biased by a spring. Switching mechanism.