JPH04210153A - Straight motion mechanism - Google Patents

Abstract

PURPOSE:To obtain a small, large-propulsion, highly-durable mechanism for rectilinear motion which converts rotary motion to rectilinear motion by driving a passive rack by means of oscillating positive racks via rollers. CONSTITUTION:A mechanism for rectlinear motion includes a passive rack 11 having a plurality of wavy teeth T1, a plurality of positive racks 12A to 12C in each of which a plurality of circular teeth T2 are formed by rollers arranged at almost the same pitch as the teeth T1 of the passive rack 11, and crankshafts 15A, 15B supporting the positive racks 12A to 12C with a predetermined phase difference and putting each of the positive racks in oscillating crank motion, and the passive rack 11 is made to travel straight while each of the plural passive racks 12A to 12C is put in eccentric circular motion by rotation of each crankshaft 15A, 15B; or the passive racks 12A to 12C are made to travel straight.

Description

[Detailed description of the invention]

[00011

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion mechanism that converts rotational motion into linear motion, and more particularly to a linear motion mechanism in which the conversion is performed using a swinging rack. [0002] [0002] Conventionally, the feed mechanism of a machine tool, etc. has been provided with a linear motion mechanism that converts rotational motion into linear motion. In order to meet the above requirements, a simple configuration is used. As this type of linear movement mechanism, for example, a rack and pinion mechanism shown in FIG. 7 is known. In this mechanism, the rack 2 that meshes with the pinion 1 is moved in the axial direction by the rotation of the pinion 1. A pin rack mechanism shown in FIG. 8 is also known, and in this mechanism, the direction of movement is changed between a rack 3 and a pin gear 4 that meshes with the rack 3. [0003]

[Problems to be Solved by the Invention] However, in such a conventional linear motion mechanism, the rotation of the input side members, such as the pinion 1 and the pin gear 4, is decelerated by a separate speed reducer. Therefore, there was a problem in that the linear movement mechanism became large. Also, the number of meshing teeth between pinion 1 and rack 2, or rack 3 and pin gear 4
Since the number of meshing teeth is small at around 1 or 2, in order to exert the specified rack thrust, the width of each tooth must be increased to withstand a certain amount of tooth surface pressure. This led to an increase in the size of the movement mechanism. [0004] Furthermore, when the pinion 1 rotates, the pinion 1
Since both members slide at the meshing part of the rack 2 and the rack 2, when the thrust is increased, the tooth surfaces are likely to wear heavily, causing looseness and seizing, which also poses problems in terms of durability. there were. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a linear movement mechanism that is small in size, has a large rack thrust, and is highly durable. [0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a passive rack having a plurality of wave-shaped teeth and a plurality of rollers arranged at substantially the same pitch as the teeth of the passive rack. teeth are formed, each supporting a plurality of active racks with the teeth in contact with a passive rack, and a plurality of active racks while maintaining a predetermined phase difference, and swinging the plurality of active racks with the phase difference. The apparatus is characterized by comprising a crankshaft for dynamic crank movement. [0006]

[Operation] In the present invention, a plurality of active racks having teeth with the same pitch as the teeth of a passive rack are supported by a crankshaft with the teeth in contact with the passive rack, and by rotation of the crankshaft, a plurality of active racks are The active rack performs rocking crank motion while maintaining a predetermined phase difference. Therefore, when the crankshaft rotates, the passive rack is always pushed in the propulsion direction by at least one of the active racks, resulting in linear movement of the passive rack. [0007] Also, at this time, since the passive rack and the active rack have a large number of teeth in contact with each other, the tooth surface pressure does not increase too much even if both racks are made small, and a linear motion mechanism with a large thrust even though it is small is not possible. It becomes realizable. Furthermore, since the teeth of the active rack are rollers, the teeth of the passive rack and the teeth of the active rack roll into contact, which prevents wear and seizure of the tooth surfaces of both racks, resulting in a highly durable linear motion mechanism. Become. [0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. 1 to 6 are diagrams showing one embodiment of the present invention. First, the configuration will be explained. 1 to 4, 11 is a plurality of teeth T
Passive racks 12A, 12B, and 12C having No. 1 are a plurality of (three in this embodiment) active racks in which a plurality of teeth T2 having the same pitch as the pitch P of the teeth TI of the passive rack 11 are formed. The teeth T1 of the passive rack 11 are formed in a trochoidal or cycloidal curve (waveform) tooth profile as shown in FIG. It is formed into an arcuate tooth shape (details will be described later) having a radius R. Further, the passive rack 11 is connected to the case 14 via a plurality of circulating balls 13 so as to be movable in the axial direction.
A is formed in the bottom 14a of the case 14, and a ball circulation passage 14b is formed in the bottom 14a of the case 14. [0009] The active racks 12A to 12C include eccentric cam portions 15a of the pair of crankshafts 15A and 15B so that the tooth T2 side of each of the racks faces the passive rack 11,
15b, 15c, and the crankshaft 15A,
15B is supported by the case 14 via each pair of bearings 19, 20, so that the teeth T2 of each of the active racks 12A to 12C are in contact with the passive rack 11. Further, the crankshafts 15A and 15B have a plurality of circular eccentric cam portions 15a.
gears 16A and 15c are formed at equal angular intervals, for example, and are connected to one end side of the crankshafts 15A and 15B;
When 16B rotates, the plurality of active racks 12A-12
C can be caused to swing crank while maintaining a predetermined phase difference (in this example, an equal phase difference of 120° corresponding to the number of active racks). Input gear 1 is input to gears 16A and 16B.
7 are in mesh with each other, and the input gear 17 is connected to an input shaft 18 which is pivotally supported by the case 14 by a bearing (not shown). One end of this input shaft 18 is connected to the case 14.
The shaft protrudes outward from the shaft, and rotational input is input from one end of the shaft. [00101 On the other hand, as shown in FIG.
Each tooth T2 of A to 12C is formed by a roller 21 having the radius R described above. The rollers 21 are rotatably supported via a plurality of needle rollers 24 on bins 23 fitted into the rack bodies 22 of the active racks 12A to 12C, and in this state, a portion of each roller 21 is A plurality of arc-shaped teeth T2 are formed by being embedded in a recess 22a formed in the main body 22. [0011] In addition, in FIGS. 1 to 3, 31.32.
33 is a needle bearing interposed between the active rack 12 and the eccentric cam portions 15a, 15b, 15c of the crankshafts 15A, 15B; 34 is a key for fixing the gears 16A, 16B to the crankshafts 15A, 15B; 35 is case 14
36 is a bottle that fixes the lid 14c of the case 14, 37.38 is a bearing 19.20
A plurality of retaining rings 39 each regulate the axial displacement of the case 14 and the crankshafts 15A, 15B through the retaining rings 39, which are stoppers that determine the moving end of the passive rack 11. [0012] Next, the operation will be explained. When the input shaft 18 is rotated by external power, the input gear 17 rotates, and the gears 16A and 16 that mesh with the input gear 17 rotate.
By rotating B in the same rotational direction, the crankshafts 15A and 15B are driven, and the plurality of active racks 12A to 12B are driven.
12C performs rocking crank motion while maintaining a predetermined phase difference. [0013] At this time, as the crankshafts 15A and 15B rotate, for example, the active rack 12A moves as shown in FIGS.
As shown in C), the active racks 12A to 12 swing eccentrically.
Passive rack 11 whose one side of tooth T1 is pushed by tooth T2 of C
moves in the direction of arrow X in FIG. In addition, the active rack 12
Since the racks A to 12C perform rocking crank motion while maintaining a predetermined phase difference corresponding to the number of active racks, at least one of the plurality of active racks 12A to 12C is rotated by the tooth T1 during one rotation of the crankshafts 15A and 15B. The negative surface side comes into contact with the passive rack 11, and the swinging of the active rack pushes the passive rack 11 in the direction of arrow X. Therefore, when the crankshafts 15A and 15B rotate once, the passive rack 1
1 moves by one tooth (pitch) of teeth Tl and T2. On the other hand, when the rotational input to the input shaft 18 is reversed, the crankshafts 15A and 15B are reversed, and the passive rack 11 moves in the opposite direction to the arrow X direction. [0014] Now, considering the meshing between the teeth T1 of the passive rack 11 and the teeth T2 of the active racks L2A to 12C while the passive rack 11 is moving, the passive rack 1
1, each tooth T1. The pressure applied to T2 can be small. Therefore, a linear motion mechanism with large thrust can be realized. Also, due to the crank motion of the active racks 12A to 12C, the passive rack 1
Since the deceleration output equivalent to one tooth T1 can be obtained, there is no need to separately install a reducer, and together with the low tooth surface pressure, a very compact linear motion mechanism can be realized. . [0015] Further, in this embodiment, the teeth T2 of the active racks 12A to 12C are composed of rollers 21, and the teeth T2 of the active racks 12A to 12C are
Since the teeth T2 of C roll into contact with each other, wear and seizure of the tooth surfaces of the passive rack 11 and the active racks 12A to 12C are prevented compared to the conventional case where the tooth surfaces slide.
It becomes a highly durable linear motion mechanism. Moreover, it can be made into a rectangular configuration by combining racks together, and it can be made simple and highly reliable by using balls 13 or the like as a structure for guiding the passive rack 11. [0016]

According to the present invention, a plurality of active racks, each of which has a plurality of teeth constituted by rollers, are caused to perform rocking crank motion while maintaining a predetermined phase difference by rotation of a crankshaft.
While these crankshafts are rotating, one of the active racks always pushes the passive rack in the propulsion direction, so the passive rack and active rack are brought into contact with many teeth to reduce tooth surface pressure. , it is possible to realize a compact linear motion mechanism with a large thrust, and the teeth of the passive rack and the teeth of the active rack are brought into rolling contact to prevent wear and seizure of the tooth surfaces of both racks, which increases durability. A highly linear motion mechanism can be realized.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of a linear movement mechanism according to the present invention.

FIG. 2 is an external front view of one embodiment.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a configuration diagram of an active rack according to one embodiment.

FIG. 5 is an explanatory diagram of a passive rack tooth profile of one embodiment.

FIG. 6 is an explanatory diagram of the operation of one embodiment.

FIG. 7 is a configuration diagram of a conventional rack and pinion mechanism.

FIG. 8 is a configuration diagram of a conventional bin rack mechanism.

[Explanation of symbols]

11 Passive rack 12A, 12B, 12C active rack 15A, 15B Crankshaft 16A, 16B Gear 17 Human powered gear 21 Roller 22 Rack body 23 bottle 24 Needle roller T1 Passive rack teeth T2 Active rack teeth

[Figure 1]

[Figure 6]

Claims (1)

[Claims] Claim 1: A plurality of arc-shaped teeth are formed by a passive rack having a plurality of wave-shaped teeth and a plurality of rollers arranged at substantially the same pitch as the teeth of the passive rack, each of which allows the tooth to be connected to the passive rack. It is characterized by comprising a plurality of active racks brought into contact with each other, and a crankshaft that supports the plurality of active racks while maintaining a predetermined phase difference and causes the plurality of active racks to perform rocking crank motion using the phase difference. A linear motion mechanism with