JPH0131805Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an output compensation device for a bearing-type transmission that uses a bearing planetary mechanism to accelerate or decelerate the rotation of a drive shaft and transmit the accelerated or decelerated rotation to the rotating shaft. .

(Conventional structure and its problems) Conventionally, in a bearing type transmission, for example, a drive shaft is attached to a ball bearing retainer to which an outer race is fixed, and a driven shaft is attached to an inner race, and the drive shaft is rotated. Then, the rotation of the drive shaft is decelerated and transmitted to the driven shaft, and when the drive shaft is attached to the inner race of a ball bearing to which the outer race is fixed, and the driven shaft is attached to the retainer, the drive shaft is rotated. , the rotation of the drive shaft was accelerated and transmitted to the driven shaft. However, in a bearing type transmission, the guide groove and ball of the outer race and the guide groove and ball of the inner race are only in point contact with each other, so the mutual contact force is weak, and when a load is applied to the driven shaft, However, there was a drawback that slippage occurred at each contact point, and the efficiency of transmitting rotation from the drive shaft to the driven shaft was significantly reduced.

(Purpose of the invention) The purpose of the invention is to increase the contact pressure at the contact point between the guide groove of the outer race and the ball and the contact point between the guide groove of the inner race and the ball when a load is applied to the driven shaft. The objective is to improve the transmission rate of rotation from the drive shaft to the driven shaft when a load is applied to the drive shaft.

(Structure of the invention) In the present invention, when a load is applied to the second driven shaft and a rotational speed difference occurs between the first driven shaft and the second driven shaft, the first driven shaft engages with each other. The contact points between the protrusions on the shaft and the second driven shaft are shifted toward the apex of the spherical surface, and the first driven shaft is pushed in the direction of the bearing type transmission, whereby each part of the bearing type transmission is This is to compensate for the drop in output by increasing the contact pressure between the two.

(Description of Embodiment) Fig. 1 shows the configuration of an embodiment of the present invention, in which 1 is a case of the shank part of a dental handpiece, 2 is a power part (not shown) at the rear end of the shank part. ) is connected to the rotating shaft (not shown) of the electric motor built into the power unit,
3 is fixed to the inner periphery of the case 1 and includes an outer race 5 having a guide groove 4 on the inner periphery, a rotatable inner race 7 having a guide groove 6 on the outer periphery, and the guide groove 4 and the guide groove. 10 is a bearing type transmission consisting of a plurality of balls 8 fitted between the drive shaft 2 and the retainer 9, and a retainer 9 interposed between the balls 8.
This connecting tube 10 is formed integrally with the retainer 9. Reference numeral 11 denotes a ball bearing for rotatably supporting the drive shaft 2, which has a connecting tube 10 connected to its tip, in the case 1. Reference numeral 12 denotes a ball bearing provided on the outside of the tip surface so as to be equidistant from the center and equidistant from each other. The first driven shaft 12 has a plurality of holes 13 recessed therein and a spring receiving hole 14 recessed in the center of its tip surface.This first driven shaft 12 is fixed to the inner race 7. Balls 15 are loosely inserted into a plurality of holes 13 so as to protrude about half from the tip surface of the driven shaft 12 (see FIG. This is a second driven shaft having a plurality of holes 17 recessed therein at equal intervals, and a spring receiving hole 18 recessed in the center of the tip surface. are located at positions corresponding to the spring receiving holes 14, respectively. 19 is the driven shaft 16
The balls are loosely inserted into each of the holes 17 so that they protrude about half from the tip surface of the ball [Fig. 1 b
], 20 is a gear fixed to the tip of the second driven shaft 16, and 21 is a gear fixed to the tip of the second driven shaft 16.
A ball bearing 22 is a spring interposed between the spring receiving hole 14 and the spring receiving hole 18, and the tension of the spring 22 causes the first driven shaft 12 and The second driven shafts 16 are biased in opposite directions to increase the contact force between the guide groove 6 and the ball 8 and the contact force between the guide groove 4 and the ball 8 in advance. 23 is a rotating shaft 24 of the head portion (not shown)
This gear 23, which is a gear fixed to the rear end, meshes with the gear 20 when the rear end of the head part is connected to the tip of the case 1 of the shank part.

In this embodiment configured in this way, the drive shaft 2
is driven and the retainer 9 rotates, the contact force generated between the balls 8 and the guide groove 4 causes the balls 8 to revolve around the guide groove 4 while rotating, and the balls 8 and the guide groove 4 to rotate. 6, the inner race 7 rotates and the first driven shaft 12 is driven. The rotation of the driven shaft 12 causes the rotation of the second driven shaft 16
is transmitted to. By the way, the drive shaft 2 is in a state where the head part is attached to the tip of the case 1, the gear 23 is meshed with the gear 20, and a cutting tool etc. (not shown) is attached to the head part, that is, in an almost unloaded state. Even if the drive shaft 2 is driven, the rotational speeds of the first driven shaft 12 and the second driven shaft 16 are the same, and the engagement position of the balls 15 and 19 is the same as when the drive shaft 2 is stopped. There is almost no change from the engaged position. However, when the drive shaft 2 is driven in a state where a cutting tool or the like is in contact with the workpiece, that is, in a loaded state, the first driven shaft 12 tries to maintain the rotational speed in the no-load state, but the second Since the rotation speed of the driven shaft 16 is slower than that in the no-load state, the first
A torsional force acts between the driven shaft 12 and the second driven shaft 16, the ball 15 rides on the ball 19, and the first driven shaft 12 and the second driven shaft 16
move in opposite directions. For this reason, the guide groove 6
The contact force between the guide groove 4 and the ball 8 and the contact force between the guide groove 4 and the ball 8 are further increased, and the transmission rate of rotation from the drive shaft 2 to the first driven shaft 12 is improved.
The decrease in the output of the second driven shaft 16 due to cutting resistance is compensated for.

FIG. 2 shows the configuration of another embodiment of the present invention, in which the same reference numerals as those in FIG. 26 is a groove recessed in the inner peripheral wall surface of the second driven shaft 16 in the direction of the center line, and 27 is a plurality of holes formed on the outer side of the rear end surface at equal distances from the center and at equal intervals from each other. 28 is recessed and grooves 29 are recessed in the outer peripheral wall surface in the direction of the center line, and the holes 28 are located at positions corresponding to the holes 13, respectively. A ball 30 is loosely inserted between the groove 26 and the groove 29, and this ball 30 is inserted into the slider hole 25.
The moving direction of the slider 27, which is movably inserted in the slider 27, is regulated in the direction of the center line. 31 projects about half from the rear end surface of the slider 27,
The balls 32 are loosely inserted into the holes 28, respectively.
The first driven shaft 12 and the second driven shaft 16 are biased in opposite directions by the tension of the spring 32, which is interposed between the driven shaft 16 and the slider 27. The contact force between the guide groove 6 and the ball 8 and the contact force between the guide groove 4 and the ball 8 are increased in advance.

In this embodiment configured in this way, the drive shaft 2
is driven and the retainer 9 rotates, the contact force generated between the balls 8 and the guide groove 4 causes the balls 8 to rotate and revolve along the guide groove 4, and the balls 8 and the guide groove 4 to rotate. Due to the contact force generated between the inner race 7 and the groove 6, the first driven shaft 12 is driven, and via the balls 15 and 31 that engage with each other in the circumferential direction, The rotation of the first driven shaft 12 causes the rotation of the second driven shaft 16
is transmitted to. By the way, the drive shaft 2 is installed in the head section at the tip of the case 1, the gear 23 is meshed with the gear 20, and a cutting tool etc. (not shown) is attached to the head section, that is, in an almost unloaded state. Even if the drive shaft 2 is driven, the rotational speeds of the first driven shaft 12 and the second driven shaft 16 are the same, and the engagement position of the balls 15 and 31 is the same as when the drive shaft 2 is stopped. There is almost no change from the engaged position. However, when the drive shaft 2 is driven in a state where a cutting tool or the like is in contact with the workpiece, that is, in a loaded state, the first driven shaft 12 tries to maintain the rotational speed in the no-load state, but the second Since the rotation speed of the driven shaft 16 is slower than that in the no-load state, the first
A torsional force acts between the driven shaft 12 and the second driven shaft 16, and the ball 15 rides on the ball 31, causing the first driven shaft 12 and the second driven shaft 16 to
move in opposite directions. For this reason, the guide groove 6
The contact force between the guide groove 4 and the ball 8 and the contact force between the guide groove 4 and the ball 8 are further increased, and the transmission rate of rotation from the drive shaft 2 to the first driven shaft 12 is improved.
The decrease in the output of the second driven shaft 16 due to cutting resistance is compensated for.

Note that the present invention can be used for tools other than dental handpieces as long as they are equipped with a bearing type transmission device. Further, as described above, the hemispherical protrusions protruding from the surfaces facing the first and second driven shafts allow the ball to be inserted into the holes drilled in the surfaces facing the first and second driven shafts, respectively. It may be inserted and shaped, or
A hemispherical protrusion may be cut on each surface facing the first and second driven shafts.

(Effect of the invention) As explained above, according to the invention, the first ball protruding roundly from the end face of the first driven shaft and the second ball roundly protruding from the end face of the second driven shaft. Since the engaged state is very unstable with respect to the torsional direction of the first and second driven shafts, even a slight load change in the driven mechanism causes the second ball of the first ball to
The movement of the ball to run onto the ball is performed smoothly, and the response speed of output compensation becomes faster. As a result, in the case of handpieces that require extremely delicate operations such as those used in dental treatment, the output fluctuations of the Hiko drive mechanism due to load fluctuations are reduced, improving the operability of the handpiece and improving the operability of the handpiece. This has the effect of shortening treatment time or processing time for dental technicians, etc.

Further, the output compensation device of the present invention has a simple structure consisting of holes drilled in the opposing surfaces of the first driven shaft and the second driven shaft, respectively, and a bow that is loosely inserted into the holes.
Since there is no need to adjust the positions of the first and second balls, assembly is simple and manufacturing costs are low.

Furthermore, the output compensator of the present invention is provided with balls for bearings, which are generally sold, in the first and second positions.
When used as a ball, the production cost is further reduced, and the movement between the first and second balls, whose surfaces are mirror-finished, becomes smoother, resulting in faster response speed for output compensation. It has the effect of becoming.

[Brief explanation of the drawing]

FIG. 1a is a cross-sectional view of the shank portion of a dental handpiece equipped with an embodiment of the present invention, FIG. 1b is a front view of an embodiment of the present invention, and FIG. 2 is another embodiment of the present invention. 1 is a cross-sectional view of a shank portion of a dental handpiece with an example; FIG. 2... Drive shaft, 3... Bearing type transmission, 4, 6...
...Guide groove, 5...Outer race, 7...Inner race,
8, 15, 19, 30, 31...ball, 9...
Retainer, 12...first driven shaft, 13, 17,
28... Hole, 16... Second driven shaft, 22, 32
...Spring, 27...Slider.

Claims (1)

[Claims for Utility Model Registration] In a bearing type transmission that accelerates or decelerates the rotation of a drive shaft and transmits the rotation to the rotating shaft using a bearing planetary mechanism, a first driven gear whose one end is connected to the bearing type transmission; a second driven shaft whose one end is connected to the driven mechanism via the rotating shaft; a hole formed in the other end surface of the first driven shaft; and a second driven shaft other than the first driven shaft. the second facing the end surface;
a hole recessed in the other end surface of the driven shaft; a first ball installed in the hole of the first driven shaft so as to protrude from the other end surface of the first driven shaft; a second ball that is mounted in a hole of the second driven shaft so as to protrude from the other end surface of the driven shaft and engages with a ball of the first driven shaft; When a load is applied, the first
When the ball rides on the second ball, the first driven shaft moves in the thrust direction and the contact pressure between the parts of the bearing type transmission increases, so that the bearing type transmission An output compensation device for a bearing type transmission, characterized in that a decrease in output in the machine is compensated for.