JPH0587692B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a ball clutch engagement device, and is particularly used in small work vehicles such as rice transplanters, tillers, and excavators to prevent balls from falling. This invention relates to a ball clutch engagement device in which the contact surface of the ball clutch is increased to improve surface pressure strength.

[Prior Art] A conventional ball clutch of this type is shown in Figs. 4 to 7 of the appendix. FIG. 4 shows a ball clutch for switching forward and backward movement, where 1 is a forward gear, 2 is a reverse gear, cylindrical extensions 3 and 4 are provided facing each other, and both gears 1 and 2 are They each freely rotate on the driven shaft 5 in opposite directions. Holes 6, 6... are bored in the extending portions 3, 4 at equal intervals in the circumferential direction, and the respective holes 6, 6...
Hesteel balls 7, 7... are inserted.
Further, as shown in FIG. 5, on the surface of the driven shaft 5, spline grooves having the same pitch in the circumferential direction as the holes 6, 6... are formed to form depressions 8, 8... be. The width of the spline groove of the depressed portion 8 is larger than that of the ball 7, and play is provided to facilitate the engagement of the ball 7 with the depressed portion 8.

When the slider 9 fitted onto the driven shaft 5 and the extension parts 3 and 4 of each gear is slid in the axial direction by the shifter 10, the forward gear 1 is shifted as shown by the chain line.
Alternatively, one of the balls 7, 7, . . . of the reverse gear 2 sinks into the depressed portion 8 of the driven shaft 5 and becomes engaged, and forward or reverse driving force is transmitted to the driven shaft 5.

Furthermore, as shown in FIG. 6, a structure in which a plurality of rows of depressions 12, 12, . . . are formed on the surface of the driven shaft 11 at positions corresponding to the holes 6, 6, . The depressed portion 12 is a long groove extending in the circumferential direction, and both ends 12a, 12a in the circumferential direction thereof are rounded to match the shape of the ball 7, as shown in FIG.

[Problems to be Solved by the Invention] The conventional ball clutch shown in FIGS. 4 and 5 has play in order to make it easier for the ball 7 to engage with the depressed portion 8. If it is made larger, the ball 7 will violently collide with the side wall portion 8a of the depressed portion 8 when it engages with the depressed portion 8. Since the depressed portion 8 is a spline groove, its side wall portion 8a is formed linearly in the axial direction, and the ball 7 is in point contact with the side wall portion 8a, resulting in insufficient strength of the side wall portion 8a. In such a case, there is a possibility that the side wall portion 8a may be given a dent d or may be missing.

On the other hand, the driven shaft 11 shown in FIG. 6 and FIG.
Since a is rounded, it is easy to engage the ball 7, but it takes time to form the depressed portion 12 by end milling, which increases costs.

Therefore, a technical problem has arisen that needs to be solved in order to provide an appropriate amount of play in the recessed part, increase the surface pressure strength against the ball, and improve the durability of the engaging part of the ball clutch at a low processing cost. The purpose of the present invention is to solve this problem.

[Means for Solving the Problems] The present invention has been proposed to achieve the above object, and the ball is engaged with and disengaged from the depressed portion of the driven shaft by sliding of the slider fitted onto the driven shaft. In the ball clutch, the forward and backward switching shafts, which are driven shafts, are independently pivoted in parallel on the left and right inside the gear case.
In addition, the forward gear and the reverse gear are pivotally attached to each of the forward/reverse switching shafts so as to freely rotate, and a spline groove is formed in the axial direction on the surface of the forward/reverse switching shaft to form a depression, so that the forward gear can be rotated freely. A semicircular ball support groove is provided on the side wall of the spline groove in the forward rotation direction in the area where the ball engages, and a semicircular ball support groove is provided on the side wall of the spline groove in the reverse rotation direction in the area where the ball of the reverse gear engages. It is an object of the present invention to provide an engaging device for a ball clutch characterized in that it is provided with a support groove.

[Function] In the present invention, a semicircular ball support groove is provided in the side wall of a spline groove bored in the axial direction to form a depressed portion, and the groove is sufficiently formed in the direction of rotation of the driven shaft to prevent engagement of the ball. There are some fun activities. Therefore,
The ball easily engages with the depressed portion, and the ball is less likely to be bounced back when engaged. Moreover, since the ball support groove is formed in a semicircular shape, it comes into line contact or surface contact with the ball, increasing surface pressure strength. Therefore, even if the ball collides with the end of the depressed portion during engagement, there is no risk of damage such as dents to the end.

Further, the ball support groove is formed by end milling after machining the spline groove, but since only the side wall of the spline groove in the rotational direction is semicircularly machined, the end milling can be done in a short time and the machining cost is low.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4 of the attached drawings. For convenience of explanation, conventionally known technical matters will also be explained at the same time. 1 and 2 show a ball clutch in a gear case, and reference numeral 21 is a gear case, in which an input shaft 22, an auxiliary transmission shaft 23, and left and right forward/reverse switching shafts 24, 24 are pivoted in parallel in the longitudinal direction. has been done. A forward gear 25 and a reverse gear 26 are rotatably pivotally connected to the forward/reverse switching shaft 24, and the forward gear 25
meshes with the drive gear 27 of the auxiliary transmission shaft 23 to transmit forward driving force, while the reverse gear 26 meshes with the drive gear 27 of the auxiliary transmission shaft 23 and
The rearward driving force is transmitted by meshing with a transmission gear 28 which is fitted onto the outer part of the transmission gear 2 and rotates freely. The forward gear 25 and the reverse gear 25 are provided with cylindrical extensions 29 and 30 facing each other, and holes 31, 31, . . . and 32, 32, . Open the steel balls 33, 33... and 34, 34.
... has been inserted.

FIG. 3 is a slope view of the forward/reverse switching shaft 24, and if explained in conjunction with FIGS. 1 and 2, the holes 31, 31, . . . and 32,
Spline grooves 35, 35... having the same pitch in the circumferential direction as 32... are bored to form a depressed portion of the ball. Semicircular ball support grooves 36, 36... are provided in the side wall portion of the forward/reverse switching shaft 24 in the forward rotational direction at the portions of the spline grooves 35, 35... that the balls 33, 33... engage with. ,3
4 are engaged with semicircular ball support grooves 37, 37, .

On the other hand, as shown in FIG. 1, a slider 38 is externally fitted onto both of the extension portions 29 and 30 so as to be slidable in the axial direction, and a flange-shaped locking portion is formed on the outer circumference of the slider 38. 39, press pieces 41, 41 of the shifter 40
is engaged. This shifter 40 is formed in a semicircular arc shape when viewed from the front, and its upper end 40a is connected to the gear case 2.
It protrudes outward from the slider portion 41 of No. 1.
A shift arm 43 is fastened to the upper end portion 40a protruding from the gear case 21 with a nut 44.

Therefore, in order to operate the ball clutch in this embodiment, the operator operates a control lever (not shown) for switching forward or backward movement on either the left or right side, and the ball clutch is operated via a link or the like. The shift arm 43 is operated, and the slider 42 is slid forward or backward via the shifter 40. Therefore, either the balls 33, 33... of the holes 31, 31... or the balls 34, 34... of the holes 32, 32... sink into the spline grooves 35, 35... of the forward/reverse switching shaft 24, and the forward driving force or The reverse driving force is transmitted to the forward/reverse switching shaft 24.

Here, the procedure for forming a depression in the forward/reverse switching shaft 24 will be described. First, the round shaft is pulled out in the axial direction by broaching, and the spline grooves 35, 35, . . . are cut. Next, the ball 3
The side walls of the spline grooves in the forward rotational direction of the parts where the balls 34, 34... engage, and the side walls of the spline grooves in the backward rotational direction of the parts where the balls 34, 34... engage are cut into a semicircular shape by end milling. , ball support grooves 36, 36... and 37, 37... are formed. The spline grooves 35, 35, . . . are provided with ball support grooves 36, 36, . , 33...and 3
4, 34, etc. are easily engaged with the depressed portions and are not repelled.

Note that this invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that this invention extends to such modifications.

[Effects of the Invention] As described in detail in the above-mentioned embodiment, the present invention provides a ball support groove in the side wall portion of the spline groove, thereby creating play for the ball and making it easier to engage the ball. The ball support groove has a semicircular shape and is in line contact or surface contact with the ball, and has high contact pressure strength and can withstand strong impact when the ball is engaged. This eliminates the occurrence of dents or the like on the side wall portions unlike in the case of conventional spline grooves alone, contributing to improved operability and durability of the ball clutch.

Further, the ball support groove is formed on the side wall of the spline groove by end milling, and since it is semicircular, the end milling can be completed in a short time. Therefore, compared to the conventional depressed portion in which both ends are rounded, this invention has various effects such as significantly lower processing costs and cost reduction.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional front view of the ball clutch, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. is a perspective view of the forward/reverse switching axis. Figures 4 to 7 show a conventional example, with Figure 4 being a longitudinal cross-sectional side view of the ball clutch, Figures 5 and 6 being oblique views of the forward/reverse switching shaft, and Figure 7 showing the main points of the depression. FIG. 21... Gear case, 24... Forward/forward switching axis,
25...Forward gear, 26...Reverse gear, 33,3
4...Ball, 35...Spline groove, 36,3
7...Ball support groove, 38...Slider.

Claims (1)

[Claims] 1 In a ball clutch in which a ball engages and disengages from a recessed part of the driven shaft by sliding a slider fitted onto the driven shaft, the forward/reverse switching shaft, which is the driven shaft, is pivoted independently and parallel to each other in the gear case. In addition, the forward gear and the reverse gear are pivotally connected to each of the forward/reverse switching shafts for free rotation, and a spline groove is formed in the axial direction on the surface of the forward/reverse switching shaft to form a depressed portion. A semicircular ball support groove is provided on the side wall of the spline groove in the forward rotation direction in the area where the gear ball engages, and a semicircular ball support groove is provided on the side wall of the spline groove in the reverse rotation direction in the area where the ball of the reverse gear engages. An engaging device for a ball clutch, characterized in that it is provided with a ball support groove.