Server and server system

1 . A server comprising:

a server module comprising:

a first tray, the first tray is provided with a first connecting mechanism;

a first circuit board mounted on the first tray; and

a top cover covered on the first tray, enclosing the first circuit board between the first tray and the top cover;

and

an expansion module comprising:

a second tray, the second tray is provided with a second connecting mechanism, the second connecting mechanism matches with the first connecting mechanism, and

a second circuit board mounted on the second tray, the second circuit board is electrically connected to the first circuit board;

wherein the first tray comprises a first base plate, a first side wall, and a second side wall opposite to the first side wall, the first side wall and the second side wall are arranged on and perpendicular to the first base plate, the first base plate is equipped with a through hole providing access for electrically connecting the second circuit board to the first circuit board, the top cover is covered on the first side wall and the second side wall, the second tray comprises a second base plate, a third side wall, and a fourth side wall opposite to the third side wall, the third side wall and the fourth side wall are arranged on and perpendicular to the second base plate, the first base plate is covered on the third side wall and the fourth side wall of the second tray, the second tray further comprises a crossbeam spanning across the third side wall and fourth side wall, the crossbeam is supported on the third side wall and fourth side wall, and the first connecting mechanism further comprises a positioning hole defined on the first base plate, the second connecting mechanism further comprises a positioning pin arranged on the crossbeam, the positioning pin is configured for inserting into the positioning hole for positioning the first tray relative to the second tray, the first connecting mechanism comprises a guide slot defined on the first side wall or the second side wall, the second connecting mechanism comprises a guide pin located on the third side wall or on the fourth side wall corresponding to the guide slot, and the guide pin inserts and slides along the guide slot to connect the first connecting mechanism to the second connecting mechanism, such that the first tray is secured to the second tray; the guide slot comprises a vertical section perpendicular to the first base plate and a sliding section parallel to the first base plate, the vertical section defines an opening at an end facing the second tray, and the guide pin extends from the third side wall and/or extends form the fourth side wall into an inner space of the second tray, and the guide pin is configured for entering the guide slot from the opening; a raised portion is provided on the third side wall or on the fourth side wall, the guide pin is set on the raised portion, a recessed portion is arranged on the first side wall or the second side wall, the recessed portion concaves from the first side wall or concaves from the second side wall to an inner space of the first tray, the guide slot is defined on the recessed portion.

2 . The server of claim 1 , wherein the server module is designed with a specification of 1U, 2U, or 3U, the expansion module is designed with a specification of 1U, 2U, or 3U.

3 . The server of claim 1 , wherein the first connecting mechanism comprises more than one guide slots defined on the first side wall and the second side wall, the first side wall and the second side wall are provided with more than one recessed portions, the more than one guide slots are respectively defined on the more than one recessed portions,

the second connecting mechanism comprises more than one guide pins located on the third side wall and the fourth side wall corresponding to the more than one guide slots, and

the third side wall and the fourth side wall are provided with more than one raised portions, the more than one guide pins are respectively arranged on the more than one raised portions.

4 . The server of claim 1 , wherein the positioning hole comprises an insertion section and a fixed section, a width of the insertion section is greater than a width of the fixed section, and

the positioning pin comprises a connecting portion and a fixing portion, the connecting portion is connected to the crossbeam, the fixing portion is located at one end of the connecting portion away from the crossbeam and protrudes radially from the connecting portion, the fixing portion has a diameter between the width of the fixed section and the width of the insertion section, such that the positioning pin is prevented from loosening out of the positioning hole.

5 . The server of claim 4 , wherein the first tray further comprises a first front wall connected between the first side wall and the second side wall, the first front wall is positioned on a side of the vertical section of the guide slot away from the sliding section, the first front wall defines a limiting hole,

the second tray comprises a second front wall connected between the third side wall and the fourth side wall, the second front wall is provided with a stop corresponding to the limiting hole, the stop extends from the second front wall into an inner space of the second tray, and

the stop is configured for positioning the first tray relative to the second tray by inserting into the limiting hole.

6 . The server of claim 5 , wherein the first front wall defines more than one limiting holes, the second front wall is provided with more than one stops, the more than one stops respectively insert into the more than one limiting holes to position the first tray relative to the second tray.

7 . The server of claim 5 , wherein the server further comprises a plurality of connectors for connecting the first tray to the second tray.

8 . The server of claim 1 , wherein the first connecting mechanism further comprises more than one positioning holes defined on the first base plate, the second connecting mechanism further comprises more than one positioning pins arranged on the crossbeam, the more than one positioning pins insert into the more than one positioning holes respectively to secure the first tray relative to the second tray.

9 . The server of claim 1 , wherein the server further comprises more than one expansion modules, the second circuit board of each of the more than one expansion modules is electrically connected to the first circuit board,

the server module is equipped with the first connecting mechanism; and

each of the more than one expansion modules is equipped with the second connecting mechanism.