Improved bidirectional combined bearing

The utility model relates to an improved bidirectional combined bearing. The improved bidirectional combined bearing comprises a big shaft, a small shaft, a big bearing and a small bearing, wherein a step is arranged at one end of the big shaft; a rectangular small bearing groove is formed in the middle of the big shaft; a small shaft hole which is vertical to the big shaft is arranged on the lower part of the step; the small shaft hole vertically penetrates through the middle section of the small bearing groove; a key groove is formed at the other end of the big shaft; a screw hole is formed at the bottom of the key groove; the big bearing is installed below the big shaft close to the step; the small bearing penetrates through the small shaft hole through the small shaft and is fixedly installed inside the small bearing groove; a waist-shaped groove which is matched with a waist-shaped key is formed on one surface of a base; the big shaft penetrates through a fixing hole; the waist-shaped key is installed in