Linear motion guide unit

Patent metadata

Field	Value
Publication number	US-10294991-B2
Application number	US-201815903191-A
Country	US
Kind code	B2
Filing date	Feb 23, 2018
Priority date	Feb 23, 2017
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A linear motion guide unit prevents damage to a corner portion of an end surface of a carriage resulting from high-speed rolling of the rolling elements, and eliminates the need for strict dimensional management of facing end surfaces of the carriage and a spacer. A crowning is formed at an end portion of the carriage, and an R chamfered portion is formed at a corner of an end surface of the carriage. An R chamfered portion is formed at a corner of the end surface of the spacer. The R chamfered portions define a valley portion between the facing surfaces of the carriage and the spacer. The rolling elements roll above the valley portion while striding it to thereby be prevented from colliding against the corner portion of the end surface of the carriage, whereby damage to the corner portion of the end surface of the carriage can be prevented.

First claim

What is claimed is:

1. A linear motion guide unit comprising:
a guide rail having a first raceway groove extending along a longitudinal direction, and
a slider which has a second raceway groove facing the first raceway groove and slides in relation to the guide rail via a plurality of rolling elements serving as rolling elements and rolling in a load-carrying race composed of the first raceway groove and the second raceway groove,
the slider having a carriage in which the second raceway groove and a return passage extending in parallel with the second raceway groove are formed, and end caps which are disposed in close contact with respective opposite end surfaces of the carriage and in which arc turnaround passages are formed respectively and establish communication between the load-carrying race and the return passage,
each of the end caps comprising an end cap body which forms an outer circumferential surface of the turnaround passage, and a spacer which is disposed in a recess of the end cap body and forms an inner circumferential surface of the turnaround passage, and
crownings being formed at respective opposite ends of the second raceway groove of the carriage and each having the form of a curved surface curved toward the turnaround passage,
wherein at least a chamfered portion is formed at a corner portion of an end surface of the spacer, wherein the end surface of the spacer faces the end surface of the carriage,
on a distal end side of each of the crownings, the carriage has an R chamfered portion sloped more steeply than the crowning, and the crowning and the R chamfered portion are connected continuously without formation of a corner portion,
the chamfered portion of the spacer and the R chamfered portion of the carriage define a valley portion between mutually facing surfaces of the carriage and the spacer, and
the rolling elements roll above the valley portion while striding the valley portion.

2. The linear motion guide unit according to claim 1 , wherein an intersection point of an imaginary line extending along the inner circumferential surface of the turnaround passage of the spacer and an imaginary line extending along the end surface of the spacer is located in a region higher than a corner portion of the end surface of the carriage.

3. The linear motion guide unit according to claim 2 , wherein a top of the chamfered portion of the spacer is located in a region lower than the corner portion of the end surface of the carriage.

4. The linear motion guide unit according to claim 1 , wherein a top of the chamfered portion of the spacer is located in a region higher than an intersection point of an extension line of the crowning of the carriage and an extension line of the end surface of the carriage.

5. The linear motion guide unit according to claim 1 , wherein a top of the chamfered portion of the spacer is located within a range from an intersection point of an extension line of the crowning of the carriage and an extension line of the end surface of the carriage to a corner portion of the end surface of the carriage.

6. The linear motion guide unit according to claim 1 , wherein the chamfered portion of the spacer is an R chamfered portion.

7. The linear motion guide unit according to claim 1 , wherein the crownings of the carriage are finished by grinding, and the R chamfered portions of the carriage are mirror-finished by use of polishing tape.

Assignees

• Nippon Thompson Co Ltd

Inventors

• Kito Kunihiko
• Narita Kentaro
• Yoshida Masaharu

Classifications

• F16C29/065 Primary

  with rollers · CPC title

• F16C29/0638 Primary

  with balls · CPC title

• F16C2223/02

  Mechanical treatment, e.g. finishing · CPC title

• F16C2240/50

  Crowning, e.g. crowning height or crowning radius · CPC title

• F16C29/0657

  with two rows of balls, one on each side of the rail · CPC title