JPH0480261B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ball screw device used in a table moving mechanism of a measuring device, etc., and in particular, a ball screw device in which a pair of half-split nuts are screwed onto a screw shaft through balls. This relates to a ball screw device that has been fitted with a ball screw device.

[Prior Art] A mechanism has been known for a long time in general measuring equipment, etc., in which the feed can be switched between automatic and manual by using a half-split nut in the feed screw device when the ball screw is not in use. . In other words, this type of feed screw device performs automatic feeding when the half-split nut is closed and screwed onto the screw shaft, and can perform manual feeding when the half-split nut is opened radially and released from the screwed state. It's becoming like that.

Additionally, in general, in a table moving mechanism using a ball screw device, for example, when attempting to start automatic feeding of the table from an arbitrary position, a means is required to quickly move the table to that arbitrary position. By adding a speed change mechanism to the ball screw device,
Devices that can rapidly move to a desired position have also been used.

[Problems to be Solved by the Invention] When using a half-split nut method in a conventional ball screw device, when the half-split nut is opened in the radial direction and released from the screwed state, the screw shaft and the nut face each other. Since the balls rolling on the threaded groove surface would fall off, a means to hold the balls against the nut was required. However, it was difficult to realize such a holding means for preventing balls from falling off.

In addition, when adding a speed change mechanism to a conventional ball screw device, even if you use rapid traverse to move the table to a desired position, it lacks speed and work efficiency is poor. There were drawbacks such as the equipment being expensive.

[Means for Solving the Problems] In order to solve the problems of conventional ball screw devices, the present invention provides a screw shaft having a male thread groove, a plurality of balls that roll on the male thread grooves, and a screw shaft that rotates through the balls. In a ball screw device consisting of a nut having a female thread groove that is screwed onto a screw shaft, the nut is divided in the axial direction and communicates with both ends of the female thread groove in which the balls roll to circulate the balls. At least one pair of half-split nuts each independently provided with a circulation path, and a ball is fixed in the female thread groove of each half-nut to an arcuate linear portion held in the half-split nut and the half-split nut. The structure includes a linear holder having both planar extension ends of a linear portion, and an relief groove formed at the bottom of the female thread groove.

[Function] In the ball screw device of the present invention, since the nut is formed of at least one pair of half nuts, each half nut can be opened and closed by moving in the radial direction. When the half nut is closed, the male thread groove and the female thread groove are screwed together through the balls, and when the half nut is moved radially from the screw shaft and opened, the balls are held by the linear part of the linear holder. It is designed to prevent it from falling off the half-split nut.

By using the half-split nut system to prevent the balls from falling off, it became possible to quickly move the table manually without adding an expensive transmission mechanism.

[Example] In FIG. 1, 1 is a ball screw device, and the ball screw device 1 has a screw shaft 2 and a nut 3.
A male thread groove 4 is formed on the outer peripheral surface of the screw shaft 2. The nut 3 is formed of a pair of half-split nuts 3a and 3b that are divided into two in the axial direction of the nut 3.

As shown in FIG. 2, each half nut 3a, 3b has a plurality of balls 5 and a linear holder 6, and a female thread groove 7 is formed on the inner surface of the half nut 3a. The ball 5 can roll in the female screw groove 7. The linear holder 6 has an arc-shaped linear part 8 in the center of the linear holder 6, and the linear part 8 allows the ball 5 to fit into the threaded groove 7 of the half-split nut.
is held so that it can roll, and both planar ends of the linear holder 6 are fixed to the half-split nut 3a by means such as machine screws 9.

Further, each half-split nut 3a, 3b is provided with a circulation path 10 through which the ball 5 circulates, as shown in FIG. A curved circulation path 11 is formed in the vicinity of the circulation path 10 connected to the female thread groove 7 of the half nut so that the rolling balls 5 can be smoothly supplied to or discharged from the female thread groove 7.

As shown in FIG. 4, the screw shaft 2 has an escape groove 12 formed at the bottom of the male thread groove 4 of the screw shaft. The escape groove 12 is formed so that the linear portion 8 of the linear holder does not come into contact when the half nuts 3a, 3b holding the balls 5 are screwed onto the screw shaft 2. The cross-sectional shape of the linear portion 8 is not limited to a rectangular shape, but a ball 5 is formed in the female thread groove 7 of the half-split nut.
It may be circular or any other shape as long as it can be held.

FIG. 6 shows another embodiment, in which the screw shaft 2
It is formed of nuts 3a, 3b, 13a, 13b and a pair of intermediate members 14a, 14b. The lower part of the nut 3 includes the lower intermediate member 14a and the lower half nuts 3a on the left and right sides of the lower intermediate member 14a,
3b are connected, and the upper part of the nut 3 is similarly connected to the intermediate member 14b and the half nuts 3a, 3b. The ball screw device configured in this manner can obtain a larger load capacity than when using only one pair of half-split nuts. Further, it is not necessary to explain in detail, but it is also possible to construct the nut using only two sets of half-split nuts without using an intermediate member.

[Effects of the Invention] The ball screw device of the present invention includes a screw shaft having a male thread groove, a plurality of balls rolling in the male thread groove,
In a ball screw device consisting of a nut having a female thread groove that is screwed into the screw shaft through the ball,
at least one pair of half-split nuts formed by dividing a nut in the axial direction, each having independently provided circulation paths for circulating the balls and communicating with both ends of the female thread groove in which the balls roll; A linear holder is provided with an arcuate linear part that holds the ball in the half nut in the female thread groove of each half nut, and both planar extension ends of the linear part that are fixed to the half nut. By having an escape groove formed at the bottom of the female thread groove, the half-split nut method prevents the steel balls from falling off, and allows quick manual movement of the table.Moreover, it does not include an expensive speed change mechanism. Effects such as good workability were obtained as there was no need to do this.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the ball screw device of the present invention, FIG. 1 is a front view of the main part, and FIG. 2 is a half-split nut taken along line A-A in FIG. 1 in the direction of the arrow. 3 is a cross-sectional view taken along the line B-B in FIG. 2, FIG. 4 is an enlarged sectional view of the main part to explain the screwed state, and FIG. 5 is the state when the screwed state is released. FIG. 6 is a front view of the main part showing another embodiment. Explanation of symbols, 1...Ball screw device, 2...Screw shaft, 3...Nut, 3a, 3b, 13a, 13
b... Half nut, 5... Ball, 6... Linear holder, 7... Female thread groove, 8... Linear part, 10...
Circulation route, 12...let's run away.

Claims (1)

[Claims] 1. In a ball screw device comprising a screw shaft having a male thread groove, a plurality of balls rolling in the male thread groove, and a nut having a female thread groove that is screwed into the screw shaft via the balls, the nut is at least one pair of half-split nuts that are divided in an axial plane, communicate with both ends of the female thread groove in which the balls roll, and each have independently provided circulation paths for circulating the balls; , each of the half-nuts has an arcuate linear portion in the female thread groove for holding the ball in the half-nut, and planar extension ends of the linear portion that are fixed to the half-nut. A ball screw device comprising a linear holder and an escape groove formed at the bottom of the female thread groove.