Door opening and closing mechanism and refrigerator

Abstract

To provide a refrigerator that can have its door closed with small force.SOLUTION: A refrigerator 100 is characterized in that a lower door 21 elevates rollers 631 to 633 and 731 to 733 to positions higher than a front end of a first guide surface 3111 with a second cam 74 and a second cam receiver 54 before the rollers 631 to 633 and 731 to 733 reach a second guide surface 312 in a process of closing a lower opening 111. The second cam 74 and second cam receiver 54 are provided nearer a second axis A2 of rotation than the rollers 631 to 633 and 731 to 733.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to a door opening and closing mechanism and a refrigerator provided with the same.

Background Art

[0002] Patent Document 1 discloses a door opening and closing mechanism of a refrigerator (hereinafter referred to as "conventional opening and closing mechanism"). The conventional opening and closing mechanism includes a plurality of rollers and a door guide portion having a guide surface and a self-closing surface. The plurality of rollers are provided on the lower surface of the door and roll on the guide surface and the self-closing surface. The guide surface is located in front of the self-closing surface and slopes upward toward the rear (i.e., toward the storage chamber). The self-closing surface is located between the rear end of the guide surface and the storage chamber. The self-closing surface slopes downward toward the rear.

[0003] In the process of the door closing the storage chamber, the plurality of rollers roll from the front end to the rear end of the self-closing surface while descending the self-closing surface. The door receives a resistance force from the self-closing surface. The resistance force includes a rearward component. The door automatically closes the storage chamber due to the rearward component.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional opening and closing mechanism, in the process of the door closing the storage chamber, each roller needs to climb the guide surface prior to the self-closing surface. Therefore, the user needs to apply a relatively large force to the door so that each roller can climb over the guide surface.

[0006] Therefore, an object of the present invention is to provide an opening and closing mechanism and a refrigerator in which the door can automatically close the storage chamber with a relatively small force. [Means for solving the problem]

[0007] The present invention is directed toward a door opening and closing mechanism for opening and closing an opening in a main body. The opening and closing mechanism comprises a first hinge pin that connects the door to the main body so as to be rotatable in the circumferential direction of a first rotation axis, a door guide portion having a first guide surface that inclins upward toward the front of the main body from below the opening, a first contact portion located on the door away from the first rotation axis and capable of contacting the first guide surface, a first cam located on the door closer to the first rotation axis than the first contact portion and protruding downward from the door, and a first cam receiver formed in an arc shape at a position away from the first rotation axis on the main body, on which the first cam can slide, and the circumferential direction is close to the opening The first cam receiver includes a first approaching direction and a first separating direction opposite to the first approaching direction, and the first cam receiver has a first flat surface extending substantially horizontally and a first inclined surface that slopes downward toward the first approaching direction from the end of the first flat surface toward the first approaching direction, and in the process of the door rotating in the first approaching direction to close the opening, when the first cam slides on the first flat surface, the first contact portion rotates in the first approaching direction at a position above the first guide surface, and when the first cam slides on the first inclined surface, the first contact portion contacts the first guide surface. The present invention is directed toward a door opening and closing mechanism for opening and closing an opening in a main body. The opening and closing mechanism is a door opening and closing mechanism for opening and closing an opening in a main body, comprising: a first hinge pin that connects the door to the main body so as to be rotatable in the circumferential direction of a first rotation axis; a door guide portion having a first guide surface that inclins upward toward the front of the main body from below the opening; and a first contact portion located away from the first rotation axis in the door and capable of contacting the first guide surface, wherein the circumferential direction includes a first approaching direction toward the opening and a first moving away direction opposite to the first approaching direction, and comprises: a stopper located away from the first rotation axis in the door and projecting downward from the door; a first regulating position located away in the first moving away direction from the closed position where the door closes the opening and receiving the tip of the stopper in the first moving away direction; and a stopper contact portion to which a side surface of the stopper extending along the front surface of the door can contact when the tip of the stopper contacts the first stopper receiver. The present invention is directed toward a door opening and closing mechanism for opening and closing an opening in a main body.The opening and closing mechanism is a door opening and closing mechanism for opening and closing an opening in the main body, comprising: a first hinge pin that connects the door to the main body so as to be rotatable in the circumferential direction of a first rotation axis; a second hinge pin that connects the door to the main body so as to be rotatable in the circumferential direction of a second rotation axis located away from the first rotation axis in the left-right direction of the main body; a first guide groove that supports the first hinge pin when the door rotates in the circumferential direction of the first rotation axis and guides the first hinge pin when the door rotates in the circumferential direction of the second rotation axis; and a second hinge pin that supports the second hinge pin when the door rotates in the circumferential direction of the second rotation axis. , a door guide portion having a second guide groove that guides the second hinge pin when the door rotates in the circumferential direction of the first rotation axis, a first guide surface that inclins upward toward the front of the main body from below the opening, a first contact portion located away from the first rotation axis in the door and capable of contacting the first guide surface, a second contact portion located between the first contact portion and the second rotation axis in the door and capable of contacting the first guide surface, a first cam located closer to the first rotation axis than the first contact portion in the door and protruding downward from the door, and the main body The door comprises a first cam receiver formed in an arc shape at a position away from the axis of rotation, on which the first cam can slide; a second cam located closer to the second axis of rotation than the second contact portion and projecting downward in the door; and a second cam receiver formed in an arc shape at a position away from the second axis of rotation in the main body, on which the second cam can slide. The circumferential direction of the first axis of rotation includes a first approaching direction toward the opening and a first moving away direction opposite to the first approaching direction, and the circumferential direction of the second axis of rotation includes a second approaching direction toward the opening and a second moving away direction opposite to the second approaching direction. The first cam receiver has a first flat surface extending substantially horizontally and a first inclined surface that slopes downward toward the first approach direction from the end of the first flat surface in the first approach direction, and the second cam receiver has a second flat surface extending substantially horizontally and a third inclined surface that slopes downward toward the second approach direction from the end of the second flat surface in the second approach direction, and when the door rotates in the circumferential direction of one of the first and second rotation axes to close the opening, the first cam abuts against the first inclined surface and the second cam abuts against the third inclined surface.

[0008] The refrigerator according to the present invention is equipped with the opening and closing mechanism. [Effects of the Invention]

[0009] According to the above configuration, it is possible to provide an opening and closing mechanism and a refrigerator that can close the door with less force. [Brief explanation of the drawing]

[0010] [Figure 1] This is a front view of a refrigerator according to each embodiment of the present invention. [Figure 2] Figure 1 is a right side view of the refrigerator shown. [Figure 3] This is a front view showing the portion of the lower opening / closing mechanism shown in Figure 1 that is to the right of the vertical center plane of the main body. [Figure 4] Figures 1 and 3 show a cross-sectional view of the lower opening / closing mechanism along line IV-IV, taken from the right. [Figure 5] This is a plan view of the portion to the right of the vertical center plane of the main body in the lower opening / closing mechanism shown in Figure 1. [Figure 6] Figure 5 is a perspective view showing the right end of the lower door guide section. [Figure 7] Figure 5 is a perspective view showing the left end of the lower door guide section. [Figure 8] This is a bottom view of the lower door shown in Figure 1, specifically the portion to the right of the vertical center plane of the lower door. [Figure 9] This is a schematic diagram showing the entire lower surface of the lower door and the entire upper surface of the lower door guide section superimposed on each other, as shown in Figure 1. [Figure 10] This is a bottom view showing an enlarged view of the right end of the lower door shown in Figure 8. [Figure 11] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 88°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 12] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 73°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 13] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 13°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 14] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 9°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 15] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 2.5°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 16] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 1.5°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 17] It is a schematic diagram showing the entire lower surface of the lower door (opening angle 0°) shown in FIG. 1 and the entire upper surface of the lower door guide portion superimposed on each other. [Figure 18] It is a schematic diagram showing in detail the directions of the first inclined surface of the first cam receiver and the third inclined surface of the second cam receiver. [Figure 19] It is a schematic diagram showing the component force of the resistance force that the first inclined surface of the first cam receiver shown in FIG. 18 applies to the second inclined surface of the first cam. [Figure 20] It is a schematic diagram showing a modified example of the first inclined surface of the first cam receiver and the third inclined surface of the second cam receiver. [Figure 21] It is a schematic diagram showing a state in which the tip of the first stopper shown in FIG. 10 abuts against the tip of the first stopper receiver shown in FIG. 6. [Figure 22] It is a schematic diagram showing a state in which the tip of the first stopper shown in FIG. 6 is received by the second stopper receiver.

Embodiments for Carrying Out the Invention

[0011] Embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals and will not be repeated in the description.

[0012] Figure 1 is a front view of a refrigerator 100 according to one embodiment of the present invention. Figure 2 is a right side view of the refrigerator 100 shown in Figure 1. As shown in Figures 1 and 2, the refrigerator 100 comprises a main body 1, a plurality of doors 2, and a plurality of opening and closing mechanisms 3. In each figure, the vertical direction D1, the left-right direction D2, and the front-back direction D3 of the main body 1 are indicated by bidirectional arrows. The front-back direction D3 is defined as the side of the main body 1 on which the plurality of doors 2 are provided being the front. The left-right direction D2 is defined as the left and right sides toward the lower opening 111 of the main body 1. The vertical direction D1 is perpendicular to the front-back direction D3 and the left-right direction D2.

[0013] The main body 1 is roughly rectangular in shape and is symmetrical in the left-right direction D2 with respect to the vertical center plane F1 of the main body 1.

[0014] The main body 1 has a lower storage compartment 11 and an upper storage compartment 12. Each of the lower storage compartment 11 and the upper storage compartment 12 is indicated by a hidden line (dashed line). The lower storage compartment 11 is formed on the lower side of the main body 1 and has a forward-facing lower opening 111. The upper storage compartment 12 is formed on the upper side of the main body 1 and has a forward-facing upper opening 121. The user puts refrigerated items in and out of the lower storage compartment 11 and the upper storage compartment 12 through the lower opening 111 and the upper opening 121, respectively. The lower storage compartment 11 and the upper storage compartment 12 may be connected to each other. That is, the lower storage compartment 11 and the upper storage compartment 12 may constitute a single space.

[0015] The multiple doors 2 include a lower door 21 and an upper door 22.

[0016] The lower door 21 is roughly rectangular in shape when viewed from the front. The lower door 21 is symmetrical in the left-right direction D6 toward the front 211 with respect to the vertical center plane F2 of the lower door 21. Note that in Figures 1 and 2, the lower door 21 is closed, with the lower opening 111 closed. Therefore, in Figure 1, the vertical center plane F2 overlaps with the vertical center plane F1 in the front-rear direction D3. The left-right direction D6 is the same direction as the left-right direction D2 of the main body 1.

[0017] In detail, the lower door 21 has a front surface 211 and a bottom surface 212.

[0018] The lower door 21 is a double door. In detail, the lower door 21 is supported on the main body 1 so as to be rotatable in a first circumferential direction D4 of a first rotation axis A1. The first rotation axis A1 extends along the vertical direction D1 at one end of the lower door 21 in the left-right direction D6. In this embodiment, the one end is the right end. The first circumferential direction D4 includes a first approach direction D41 and a first retraction direction D42. The first approach direction D41 is the direction from a position away from the lower opening 111 to approaching the lower opening 111 in the first circumferential direction D4. The first retraction direction D42 is opposite to the first approach direction D41. In detail, the lower door 21 is rotatable in the first approach direction D41 and the first retraction direction D42 between a closed position and a fully open position. In the closed position, the lower door 21 completely closes the lower opening 111. In the fully open position, the lower door 21 opens the lower opening 111. Under normal use, the lower door 21 does not rotate beyond the fully open position in the first separation direction D42.

[0019] The lower door 21 is supported by the main body 1 so as to be rotatable in the second circumferential direction D5 of the second rotation axis A2. The second rotation axis A2 extends along the vertical direction D1 at the other end of the lower door 21 in the left-right direction D6. In this embodiment, the other end is the left end. The second rotation axis A2 is symmetric to the first rotation axis A1 with respect to the vertical center plane F2 of the lower door 21. The second circumferential direction D5 includes a second approaching direction D51 and a second moving away direction D52. The second approaching direction D51 is the direction from a position away from the lower opening 111 to approaching the lower opening 111 in the second circumferential direction D5. The second moving away direction D52 is opposite to the second approaching direction D51.

[0020] The upper door 22 differs from the lower door 21 only in that it is located above the lower door 21 and is either closer to or further away from the upper opening 121. Therefore, a description of the upper door 22 will be omitted.

[0021] The multiple opening / closing mechanisms 3 include a lower opening / closing mechanism 31 and an upper opening / closing mechanism 32. The upper opening / closing mechanism 32 has the same configuration as the lower opening / closing mechanism 31. Therefore, the configuration of the lower opening / closing mechanism 31 will be described below, and the description of the upper opening / closing mechanism 32 will be omitted.

[0022] Figure 3 is a front view showing the portion of the lower opening / closing mechanism 31 shown in Figure 1 that is to the right of the vertical center plane F1. Figure 3 is also a front view showing the portion enclosed by the oval C1 shown in Figure 1. Figure 4 is a cross-sectional view of the vertical section of the lower opening / closing mechanism 31 along line IV-IV shown in Figures 1 and 3, viewed from the right. Figure 5 is a plan view of the portion of the lower opening / closing mechanism 31 shown in Figure 1 that is to the right of the vertical center plane F1. Figure 5 is also a plan view of the cross section of the refrigerator 100 along line VV shown in Figure 3, viewed from above.

[0023] As shown in Figures 1 to 5, the lower opening / closing mechanism 31, also called the lower hinge assembly, is a component that combines a metal member and a resin member. The lower opening / closing mechanism 31 includes the lower door guide section 311.

[0024] The lower door guide portion 311 is attached to the lower edge portion 112 (see Figures 4 and 5) with multiple screws 313 (see Figure 3) so as to protrude forward relative to the lower edge portion 112. The lower edge portion 112 is the part of the periphery of the lower opening 111 (see Figure 4) in the main body 1 that extends in the left-right direction D2 directly below the lower opening 111. The lower door guide portion 311 is long in the left-right direction D2 and thin in the up-down direction D1, forming a plate-like shape. The lower door guide portion 311 extends in the left-right direction D2 between the left end and the right end of the lower edge portion 112 (see Figures 1 and 5).

[0025] In detail, the lower door guide section 311 has a first guide surface 3111 and a second guide surface 3112.

[0026] The first guide surface 3111 extends from the lower edge 112 (i.e., below the lower opening 111) toward the front of the main body 1. The first guide surface 3111 starts slightly forward from the lower edge 112 and inclines upward toward the front of the main body 1 (see Figure 4 in particular).

[0027] The second guide surface 3112 is continuous with the front end of the first guide surface 3111 and extends from the front end of the first guide surface 3111 toward the front of the main body 1. The second guide surface 3112 is inclined toward the front of the main body 1 toward the downward of the main body 1 (see Figure 4 in particular).

[0028] The rightmost end 3113 of the first guide surface 3111 and the rightmost end 3114 of the second guide surface 3112 are located to the left of the rightmost end 1121 of the lower edge portion 112 (see Figure 5 in particular). In the first guide surface 3111 and the second guide surface 3112, the portions to the left of the vertical center plane F1 are symmetrical with respect to the vertical center plane F1 of the main body 1 with respect to the portions to the right of each respective surface.

[0029] Figure 6 is a perspective view showing the right end of the lower door guide portion 311 shown in Figure 5. As shown in Figures 5 and 6, the lower opening and closing mechanism 31 includes a first engaging projection 41 (see Figure 5), a first hinge pin 42, a first arc-shaped projection 43, and a first cam receiver 44 to the right of the first guide surface 3111 and the second guide surface 3112 in the lower door guide portion 311.

[0030] The first engaging projection 41 is located to the right of the first guide surface 3111 and the second guide surface 3112, and protrudes upward from the lower door guide portion 311. The first engaging projection 41 is a metal component and is long in the front-to-back direction D3 and thin in the left-to-right direction D2.

[0031] The first hinge pin 42 is a metal component having a substantially cylindrical shape. The first hinge pin 42 is attached to the right front corner of the lower door guide portion 311 by crimping or the like. The first hinge pin 42 is located forward from the lower edge portion 112 and protrudes upward from the lower door guide portion 311. The central axis of the first hinge pin 42 coincides with the first rotation axis A1. The first hinge pin 42 connects the lower door 21 to the main body 1 so that it can rotate in the first circumferential direction D4 of the first rotation axis A1.

[0032] The first arc-shaped projection 43 is integrated with the lower door guide portion 311. The first arc-shaped projection 43 is located radially away from the first hinge pin 42 in the direction of the first rotation axis A1. The first arc-shaped projection 43 is located forward from the lower edge portion 112. The first arc-shaped projection 43 protrudes upward from the lower door guide portion 311 and extends in the first approach direction D41 (see Figure 5). In detail, the first arc-shaped projection 43 has a substantially semi-circular shape in plan view. In this embodiment, the first arc-shaped projection 43 extends from the left of the first hinge pin 42, through the rear of the first hinge pin 42, to the right of the first hinge pin 42.

[0033] The first cam bearing 44 is made of a resin material that is wear-resistant and flexible. An example of this type of material is nylon 6 (PA6). The first cam bearing 44 is located radially away from the first rotation axis A1 and extends along the first approaching direction D41 and the first separating direction D42. The first cam bearing 44 is a separate component from the first arc-shaped projection 43 and is located along the outer circumferential surface of the first arc-shaped projection 43. The first cam bearing 44 is located forward from the lower edge portion 112.

[0034] More specifically, the first cam receiver 44 has a first flat surface 441, a first inclined surface 442, and a second inclined surface 443. The first flat surface 441 is located behind the first hinge pin 42. The first flat surface 441 extends in a substantially horizontal plane along a first approach direction D41 and a first separation direction D42. The first inclined surface 442 extends from the end of the first flat surface 441 in the first approach direction D41. The first inclined surface 442 slopes downward toward the first approach direction D41. The second inclined surface 443 extends from the end of the first flat surface 441 in the first separation direction D42. The second inclined surface 443 slopes downward toward the first separation direction D42 as it moves away from the first flat surface 441.

[0035] Figure 7 is a perspective view showing the left end of the lower door guide section 311 shown in Figure 5. As shown in Figure 7, the lower opening and closing mechanism 31 includes a second hinge pin 52, a second arc-shaped projection 53, and a second cam receiver 54.

[0036] The second hinge pin 52 has a shape that is symmetrical with respect to the vertical center plane F1 with respect to the first hinge pin 42 in the left-right direction D2. The central axis of the second hinge pin 52 coincides with the second rotation axis A2. The second arc-shaped projection 53 has a shape that is symmetrical with respect to the vertical center plane F1 with respect to the first arc-shaped projection 43 (see Figure 6) in the left-right direction D2.

[0037] To the right of the second hinge pin 52, a second engaging projection 51 (see Figure 9) is provided at a position symmetrical to the first engaging projection 41 in the left-right direction D2 with respect to the vertical center plane F1. In addition, a fourth engaging projection and a fourth hinge pin are provided directly above the upper left corner of the lower door 21 in the main body 1. The fourth engaging projection has a shape symmetrical to the second engaging projection 51 in the vertical direction D1. The fourth hinge pin has a shape symmetrical to the second hinge pin 52 in the vertical direction D1 and supports the lower door 21 so that it can rotate in the second circumferential direction D5 of the second rotation axis A2.

[0038] The second cam receiver 54 has a shape that is symmetrical with respect to the second cam receiver 44 (see Figure 6) in the left-right direction D2 with respect to the vertical center plane F1 (see Figure 5). That is, the second cam receiver 54 extends along the second approach direction D51 and the second separation direction D52 at a position radially away from the second rotation axis A2. In detail, the second cam receiver 54 has a second flat surface 541, a third inclined surface 542, and a fourth inclined surface 543. The second flat surface 541 extends along the second approach direction D51 and the second separation direction D52 in a substantially horizontal plane. The third inclined surface 542 extends from the end of the second flat surface 541 in the second approach direction D51. The third inclined surface 542 is inclined downward toward the second approach direction D51. The fourth inclined surface 543 extends from the end of the second flat surface 541 in the second separation direction D52. The fourth inclined surface 543 slopes downward toward the second separation direction D52.

[0039] Figure 8 is a bottom view of the portion of the lower door 21 shown in Figure 1 that is to the right of the vertical center plane F2. As shown in Figure 8, the lower opening and closing mechanism 31 includes a first guide groove 61, a first engagement groove 62, and a plurality of first contact portions 63 on the lower surface 212 of the lower door 21 that is to the right of the vertical center plane F2.

[0040] The first guide groove 61 extends from the rear surface 213 toward the front surface 211 of the lower door 21 at the right end of the lower door 21 in the left-right direction D6. The first guide groove 61 is a recessed groove that drops upward from the bottom surface 212. When the lower door 21 rotates in the first circumferential direction D4, the first guide groove 61 rotatably supports the first hinge pin 42 (see Figure 5) at its front end. When the lower door 21 rotates in the second circumferential direction D5, the first guide groove 61 guides the first hinge pin 42 (see Figure 5) as it moves in the second approach direction D51 or the second separation direction D52.

[0041] The first engagement groove 62 is provided in cooperation with the first engagement projection 41 (see Figure 5) to prevent the lower door 21 from falling off the main body 1 even when a forward force is applied to the double-opening lower door 21. Note that the first engagement projection 41 and the first engagement groove 62 are known technologies, so a detailed explanation of each will be omitted.

[0042] Furthermore, in the main body 1, a third engaging projection similar to the first engaging projection 41 and a third hinge pin similar to the first hinge pin 42 are provided near the upper right corner of the lower door 21. A third guide groove similar to the first guide groove 61 and a third engaging groove similar to the first engaging groove 62 are provided at the upper right corner of the lower door 21.

[0043] Multiple first contact portions 63 are provided on the lower surface 212 to the right of the vertical center plane F2 and to the left of the first engagement groove 62. Therefore, the multiple first contact portions 63 are provided on the lower door 21 at positions separated in the direction from the first rotation axis A1 toward the vertical center plane F2 (i.e., to the left in the left-right direction D6). The multiple first contact portions 63 include three rollers 631, 632, and 633. Here, on the lower surface 212, between the first engagement groove 62 and the vertical center plane F2, three roller holders 634, 635, and 636 are arranged in a straight line along the rear surface 213 of the lower door 21. Each of the roller holders 634 to 636 is a recess that is recessed upward from the lower surface 212. Of the roller holders 634 to 636, roller holder 634 is located closest to the first engagement groove 62, and roller holder 636 is located furthest from the first engagement groove 62. Rollers 631 to 633 are housed in roller holders 634 to 636 such that the lower ends of each roller 631 to 633 protrude below the lower surface 212 of the lower door 21. Therefore, multiple first contact portions 63 protrude below the lower surface 212 of the lower door 21. In addition, rollers 631 to 633 are each supported by roller holders 634 to 636 so as to be rotatable around a rotation axis along the left-right direction D6 of the lower door 21.

[0044] Figure 9 is a schematic diagram showing the entire lower surface of the lower door 21 shown in Figure 1 superimposed on the entire upper surface of the lower door guide portion 311. As shown in Figure 9, the lower opening and closing mechanism 31 includes a second guide groove 71, a second engagement groove 72, and a plurality of second contact portions 73 on the lower surface 212 of the lower door 21 to the left of the vertical center surface F2.

[0045] The second guide groove 71 is symmetrical to the first guide groove 61 in the left-right direction D6 of the lower door 21 with respect to the vertical center plane F2. More specifically, the second guide groove 71 is a recessed groove extending from the rear surface 213 toward the front surface 211 of the lower door 21 at the left end in the left-right direction D2 of the lower door 21. The second guide groove 71 rotatably supports the second hinge pin 52 (see Figure 7) at its front end when the lower door 21 rotates in the second circumferential direction D5. The second guide groove 71 guides the second hinge pin 52 (see Figure 7) as it moves in the first approach direction D41 or the first separation direction D42 when the lower door 21 rotates in the first circumferential direction D4.

[0046] The second engagement groove 72 is provided to prevent the lower door 21 from falling off, and has a shape symmetrical to the first engagement groove 62 in the left-right direction D6 with respect to the vertical center plane F2. Similar to the first engagement projection 41 and the first engagement groove 62, the second engagement groove 72 works in cooperation with the second engagement projection 51 (see Figure 9) to prevent the lower door 21 from falling off.

[0047] Furthermore, in the main body 1, a fourth engaging projection similar to the second engaging projection 51 and a fourth hinge pin similar to the second hinge pin 52 are provided near the upper left corner of the lower door 21. A fourth guide groove similar to the second guide groove 71 and a fourth engaging groove similar to the second engaging groove 72 are provided at the upper left corner of the lower door 21.

[0048] The multiple second contact portions 73 are symmetrical to the multiple first contact portions 63 in the left-right direction D6 with respect to the vertical center plane F2. In detail, the multiple second contact portions 73 include three rollers 731, 732, and 733. Roller 731 is positioned symmetrically to roller 631 in the left-right direction D2 with respect to the vertical center plane F2. Roller 732 is positioned symmetrically to roller 632 in the left-right direction D2 with respect to the vertical center plane F2. Roller 733 is positioned symmetrically to roller 633 in the left-right direction D2 with respect to the vertical center plane F2. Therefore, rollers 731 to 733 are housed in roller holders 734 to 736 such that the lower ends of each roller 731 to 733 protrude below the lower surface 212 of the lower door 21. Furthermore, rollers 731 to 733 are each supported by roller holders 734 to 736 so as to be rotatable around a rotation axis along the left-right direction D6 of the lower door 21.

[0049] Figure 10 is a bottom view showing an enlarged view of the right end of the lower door 21 shown in Figure 8. As shown in Figure 10, the lower opening / closing mechanism 31 includes a first cam 64 made of a resin material that is wear-resistant and flexible. Preferably, the first cam 64 is made of a different resin material (for example, polyacetal) than the first cam receiver 44. Therefore, the generation of abnormal noise is suppressed when the first cam 64 slides on the first cam receiver 44. The first cam 64 is located radially away from the first rotation axis A1 in the lower door 21. In particular, the first cam 64 is located closer to the first rotation axis A1 than the first contact portion 63 in the lower door 21. The first cam 64 also protrudes downward to the right of the first guide groove 61.

[0050] In detail, the first cam 64 has a first flat surface 641, a first inclined surface 642, and a second inclined surface 643. The first flat surface 641 is located diagonally to the right and rear of the first rotation axis A1 toward the front surface 211. The first flat surface 641 extends in a substantially horizontal plane along the first approach direction D41 and the first separation direction D42. The first flat surface 641 is a downward-facing surface. The first inclined surface 642 extends from the end of the first flat surface 641 in the first approach direction D41. The first inclined surface 642 is inclined upward toward the first approach direction D41. The second inclined surface 643 extends from the end of the first flat surface 641 in the first separation direction D42. The second inclined surface 643 is inclined upward toward the first separation direction D42.

[0051] Figure 11 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle of 88°) shown in Figure 1 superimposed on the entire upper surface of the lower door guide portion 311. The opening angle of the lower door 21 is the angle at which the front surface 211 of the lower door 21 and the front surface of the lower edge portion 112 intersect.

[0052] As shown in Figure 11, the refrigerator 100 includes a second cam 74. The second cam 74 is symmetrical to the first cam 64 in the left-right direction D6 with respect to the vertical center plane F2 of the lower door 21 (see Figure 9). In detail, the second cam 74 is located closer to the second rotation axis A2 than the second contact portion 73 on the lower door 21. The second cam 74 also protrudes downward to the left of the second guide groove 71 in the left-right direction D6. In detail, the second cam 74 has a second flat surface 741, a third inclined surface 742, and a fourth inclined surface 743. The second flat surface 741 is located diagonally rear to the left of the second rotation axis A2 toward the front surface 211 and is located to the left of the second guide groove 71. The second flat surface 741 extends in a substantially horizontal plane along the second approach direction D51 and the second separation direction D52. The third inclined surface 742 extends from the end of the second flat surface 741 in the second approach direction D51. The third inclined surface 742 inclins upward toward the second approach direction D51. The fourth inclined surface 743 extends from the end of the second flat surface 741 in the second separation direction D52. The fourth inclined surface 743 inclins upward toward the second separation direction D52.

[0053] The lower opening / closing mechanism 31 provides an auto-closing function for the lower door 21, a centering function for the lower door 21, and a rotation restriction function for the lower door 21.

[0054] The auto-close function will be explained below with reference to Figures 11 to 17. When the user closes the lower door 21, they apply a force in the first approaching direction D41 to the lower door 21, which is located away from the lower opening 111 in the first separation direction D42.

[0055] As shown in Figure 11, when the opening angle is 88°, the first inclined surface 642 of the first cam 64 contacts the second inclined surface 443 of the first cam receiver 44 and slides on the second inclined surface 443 in the first approach direction D41. That is, the first inclined surface 642 climbs the second inclined surface 443. Therefore, the vertical height of the first inclined surface 642, i.e., the lower door 21, gradually increases. "Vertical height" refers to the position in the vertical direction D1. At this time, the left end of the lower door 21 is a fixed end and the right end of the lower door 21 is a free end, so the vertical height of the left end of the lower door 21 is higher than that of the right end. When the first inclined surface 642 of the first cam 64 rotates further in the first approach direction D41 from the state where the opening angle is 88°, it reaches the end of the first flat surface 441 of the first cam receiver 44 in the first separation direction D42.

[0056] Figure 12 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle 73°) shown in Figure 1 superimposed on the entire upper surface of the lower door guide portion 311. As shown in Figure 12, when the opening angle is 73°, the first inclined surface 642 contacts the first flat surface 441 and slides on the first flat surface 441 in the first approach direction D41. Subsequently, the first flat surface 641 of the first cam 64 reaches the end of the first flat surface 441 on the first separation direction D42 side. Thereafter, the first flat surface 641 slides on the first flat surface 441 toward the first approach direction D41.

[0057] While the first flat surface 641 slides on the first flat surface 441, the vertical height of the lower door 21 is at its highest. At this time, each of the rollers 631, 632, and 633 (see Figure 9) rotates around the first rotation axis A1 at a position above the first guide surface 3111 and the second guide surface 3112. That is, while the first flat surface 641 slides on the first flat surface 441, the rollers 631 to 633 do not roll on the second guide surface 3112 (i.e., the uphill slope). Therefore, the resistance force in the first separation direction D42 that the user receives from the lower door 21 is reduced compared to the case where the rollers 631 to 633 roll on the second guide surface 3112.

[0058] Figure 13 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle of 13°) shown in Figure 1 superimposed on the entire upper surface of the lower door guide portion 311. As shown in Figure 13, when the opening angle is 13°, the first flat surface 641 passes the first flat surface 441 in the first approach direction D41. The second inclined surface 643 reaches the end of the first inclined surface 442 in the first separation direction D42 and begins to slide on the first inclined surface 442. Thereafter, the second inclined surface 643 descends the first inclined surface 442. Accordingly, the vertical height of the lower door 21 gradually decreases. Also, in the process of the opening angle changing from 73° to 13°, the first engaging projection 41 begins to engage with the first engaging groove 62.

[0059] Figure 14 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle 9°) shown in Figure 1 superimposed on the entire upper surface of the lower door guide section 311. As shown in Figure 14, when the opening angle is 9°, the second inclined surface 643 descends the first inclined surface 442, just as when the opening angle is 13°. Inside the frame W1 at the right end of Figure 14, a cross-sectional view is shown of the longitudinal section along line XIV-XIV shown in Figure 14, viewed from the left. As shown inside the frame W1, when the opening angle is 9°, the vertical height of the roller 731, which is furthest from the first rotation axis A1 among the first contact section 63 and the second contact section 73, is higher than the vertical height of the front end of the first guide surface 3111 in the lower door guide section 311. The vertical heights of the other rollers 631-633, 732, and 733 are also higher than the vertical height of the front end of the first guide surface 3111.

[0060] Figure 15 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle 2.5°) shown in Figure 1 superimposed with the entire upper surface of the lower door guide portion 311. As shown in Figure 15, when the opening angle is 2.5°, the second inclined surface 643 descends the first inclined surface 442, just as when the opening angle is 9°. Inside the frame W2 at the right end of Figure 15, a cross-sectional view is shown of the longitudinal section along the line XV-XV shown in Figure 15, viewed from the left. As shown inside the frame W2, in the process of the opening angle changing from 9° to 2.5°, that is, in the process of the second inclined surface 643 descending the first inclined surface 442, the roller 731 furthest from the first rotation axis A1 among the first contact portion 63 and the second contact portion 73 descends to near the front end of the first guide surface 3111. Subsequently, the other rollers 631-633, 732, and 733 also descend sequentially to the first guide surface 3111. That is, as the first cam 64 moves from the first flat surface 441 to the first inclined surface 442 of the first cam receiver 44, the rollers 631-633 and 731-733 descend to the first guide surface 3111. Also, in the process of the opening angle changing from 9° to 2.5°, the second engaging projection 51 begins to engage with the second engaging groove 72, and the second hinge pin 52 begins to engage with the second guide groove 71.

[0061] Figure 16 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle of 1.5°) shown in Figure 1 superimposed with the entire upper surface of the lower door guide section 311. As shown in Figure 16, when the opening angle is 1.5°, the second inclined surface 643 descends the first inclined surface 442, just as when the opening angle is 2.5°. In Figure 16, a cross-sectional view of the longitudinal section along line XVI-XVI, viewed from the left, is shown within the frame W3. As shown within the frame W3, when the opening angle is 1.5°, the roller 731 rolls down on the first guide surface 3111. However, since the vertical height of the first guide surface 3111 decreases as it moves backward, rollers 631-633, 732, and 733 other than roller 731 do not come into contact with the first guide surface 3111. If all rollers 631-633 and 731-733 are in contact with the first guide surface 3111, the downward force acting on the lower door 21 is distributed and applied to the rollers 631-633 and 731-733. However, as in the embodiment, if only roller 731 is in contact with the first guide surface 3111 among the rollers 631-633 and 731-733, then most of the downward force acting on the lower door 21 is concentrated on roller 731. Furthermore, roller 731 is the furthest from the first rotation axis A1 among the rollers 631-633 and 731-733. Consequently, the torque for closing the lower door 21 increases, making it easier for the lower door 21 to close the lower opening 111. In addition, even if the user does not apply enough force to the lower door 21 to close it, it is possible to prevent the lower door 21 from not closing completely and creating a gap between the lower door 21 and the main body 1.

[0062] Here, after the first flat surface 641 has passed the first flat surface 441, the roller 731 rolls down on the first guide surface 3111. At this time, the lower door 21 automatically moves toward the lower opening 111 in the first approach direction D41. Furthermore, the resistance force in the second separation direction D52 that the user experiences from the lower door 21 is further reduced compared to when the first flat surface 641 passes over the first flat surface 441.

[0063] Figure 17 is a schematic diagram showing the entire lower surface of the lower door 21 (opening angle 0°) shown in Figure 1 superimposed on the entire upper surface of the lower door guide section 311. As shown in Figure 17, when the opening angle is 0°, the second inclined surface 643 stops near the end of the first approach direction D41 on the first inclined surface 442. In Figure 17, the frame W4 shows a cross-sectional view of the longitudinal section along line XVII-XVII as seen from the left. As shown in the frame W4, when the opening angle is 0°, the rear surface 213 of the lower door 21 abuts against the edge of the main body 1 and is in the closed position, completely closing the lower opening 111. When the lower door 21 is in the closed position, all rollers 631-633 and 731-733 stop on the first guide surface 3111.

[0064] As explained above with reference to Figures 11 to 17, in the refrigerator 100, during the process of closing the lower opening 111, the lower door 21 is raised by the second cam 74 and the second cam receiver 54 to a position higher than the front end of the first guide surface 3111 before the rollers 631-633 and 731-733 reach the second guide surface 312. Here, since the second cam 74 and the second cam receiver 54 are provided closer to the second rotation axis A2 than the rollers 631-633 and 731-733, the user only needs to apply a relatively small force to the lower door 21 even when the third inclined surface 742 climbs the fourth inclined surface 543. Thus, a refrigerator 100 can be provided that can close the lower door 21 with less force than conventional opening and closing mechanisms.

[0065] Furthermore, in this embodiment, while the first flat surface 641 slides on the second inclined surface 443 and the first flat surface 441, at least the roller 631 closest to the first rotation axis A1 among the first contact portion 63 and the second contact portion 73 rotates at a position above the first guide surface 3111 and the second guide surface 3112. As a result, the user can close the lower door 21 with little force.

[0066] Furthermore, the operation of the lower opening / closing mechanism 31 during the process in which the lower door 21 rotates in the second approach direction D51 to close the lower opening 111 is obvious to those skilled in the art, and therefore will not be explained.

[0067] Next, the centering function will be explained with reference to Figures 1 through 20.

[0068] The lower door 21 can rotate around both the first rotation axis A1 and the second rotation axis A2. Furthermore, the width of the first guide groove 61 is larger than the outer diameter of the first hinge pin 42 (see Figures 6 and 9), and the width of the second guide groove 71 is larger than the outer diameter of the second hinge pin 52 (see Figure 9 in particular). Therefore, the first hinge pin 42 and the second hinge pin 52 are supported by the first guide groove 61 and the second guide groove 71, respectively, with some play.

[0069] Figure 17 is a schematic diagram showing the state in which the second inclined surface 643 abuts against the first inclined surface 442 and the fourth inclined surface 743 abuts against the third inclined surface 542. As shown in Figure 17, in the process of closing the lower door 21, from the time the second inclined surface 643 begins to descend the first inclined surface 442 (see Figure 16) until the opening angle of the lower door 21 reaches 0°, the second inclined surface 643 abuts against the first inclined surface 442 and the fourth inclined surface 743 abuts against the third inclined surface 542.

[0070] Figure 18 is a schematic diagram showing in detail the orientation of the first inclined surface 442 and the third inclined surface 542 of the first cam receiver 44. Figure 19 is a schematic diagram showing the component force F31 in the left-right direction D2 of the resistance force F3 that the first inclined surface 442 applies to the second inclined surface 643, as shown in Figure 18. As shown in Figures 18 and 19, when the second inclined surface 643 of the first cam 64 contacts the first inclined surface 442 of the first cam receiver 44, the first inclined surface 442 applies a resistance force F3 to the second inclined surface 643 of the first cam 64. The direction of the resistance force F3 is perpendicular to the position P1 where the second inclined surface 643 contacts the first inclined surface 442. Here, the first inclined surface 442 is inclined downward in the first approach direction D41 and faces diagonally forward to the right in the left-right direction D2 and the front-back direction D3. Therefore, as shown in Figure 19, the drag force F3 includes a component force F31 in the left-right direction D2. More specifically, the component force F31 is a unidirectional (i.e., rightward) component in the left-right direction D2 and is the outward component of the main body 1.

[0071] Furthermore, the third inclined surface 542 is symmetric with respect to the vertical center plane F1 with respect to the first inclined surface 442 in the left-right direction D2. Therefore, the third inclined surface 542 applies a reactive force to the fourth inclined surface 743 of the second cam 74 in a direction symmetric with respect to the vertical center plane F2 in the first specific direction D71 and the left-right direction D2 (see Figure 18). This reactive force is the component in the other direction (i.e., leftward) in the left-right direction D2 and includes the component force of the outward component of the main body 1.

[0072] As described above, just before the lower door 21 closes the lower opening 111, a force is applied to the second inclined surface 643 of the lower door 21 in a rightward direction, and a force is applied to the fourth inclined surface 743 in a leftward direction. Also, the first hinge pin 42 and the second hinge pin 52 are supported by the first guide groove 61 and the second guide groove 71, respectively, with some play. Therefore, a force is applied to the lower door 21 so that the vertical center surface F2 of the lower door 21 approaches the vertical center surface F1 of the main body 1. In other words, the lower opening and closing mechanism 31 corrects the misalignment of the vertical center surfaces F1 and F2 when closing the lower door 21. Specifically, the lower opening and closing mechanism 31 brings the opening force when opening the lower door 21 around the first rotation axis A1 and the opening force when opening the lower door 21 around the second rotation axis A2 closer together so that they are equal. As a result, the operability of the double-opening lower door 21 is improved.

[0073] Here, we assume that the lower opening / closing mechanism 31 does not have a centering function. Under this assumption, if the lower door 21 is closed forcefully around the first rotation axis A1, for example, after closing the lower opening 111, it may slide to the right in the left-right direction D2 and rotate around the second rotation axis A2. However, in this embodiment, the lower opening / closing mechanism 31 has a centering function, so even when the lower door 21 closes the lower opening 111, a leftward force is applied to the fourth inclined surface 743 and a rightward force is applied to the second inclined surface 643. Therefore, even if the lower door 21 is closed forcefully around the first rotation axis A1, after closing the lower opening 111, a leftward force is applied to the fourth inclined surface 743, preventing it from sliding to the right in the left-right direction D2.

[0074] The refrigerator 100, which has a centering function, is applicable to both consumer and commercial use, but is particularly suitable for commercial use. Specifically, in the commercial refrigerator 100, a gasket made of magnetic rubber or the like is provided on the rear surface 213 of the lower door 21. Therefore, if the lower opening / closing mechanism 31 does not have a centering function, the double-opening lower door 21 closes the lower opening 111 with the vertical center surface F2 of the lower door 21 misaligned from the vertical center surface F1 of the metal body 1 due to the magnetic force of the gasket. However, in this embodiment, since the lower opening / closing mechanism 31 has a centering function, when the lower door 21 closes the lower opening 111, a leftward force is applied to the fourth inclined surface 743 and a rightward force is applied to the second inclined surface 643, against the magnetic force of the gasket. Therefore, the double lower door 21 closes the lower opening 111 with a reduced positional displacement of the vertical center surface F2 of the lower door 21 relative to the vertical center surface F1 of the main body 1.

[0075] Figure 20 is a schematic diagram showing modified versions of the first inclined surface 442 and the third inclined surface 542. As shown in Figure 20, the first inclined surface 442 of the modified version is oriented further outward from the main body 1 (i.e., to the right in the left-right direction D2) than the first inclined surface 442 of the embodiment. In detail, in Figure 20, the dashed line F42 is parallel to and tangent to the lower end of the first inclined surface 442 of the embodiment. Furthermore, extending the dashed line F42 passes through the first rotation axis A1. The first inclined surface 442 of the modified version has a base F41 on a horizontal line obtained by rotating the dashed line F42 by a predetermined angle counterclockwise (i.e., in the first separation direction D42) in a plan view. The base F41 does not pass through the first rotation axis A1 and is oriented further outward from the main body 1 than the base of the first inclined surface 442 of the embodiment. The first inclined surface 442 of the modified example is the surface traced by the base F41 when it is moved upward in the vertical direction D1 while rotating the base F41 clockwise around the first rotation axis A1 (i.e., in the first approach direction D41). The third inclined surface 542 of the modified example is symmetrical to the first inclined surface 442 in the left-right direction D2 with respect to the vertical center plane F2. Therefore, compared to the first inclined surface 442 of the cam receiver 44 shown in Figure 18, the second inclined surface 643 generates a horizontal component force that is more outward to the right, and the fourth inclined surface 743 generates a horizontal component force that is more outward to the left. As the first inclined surface 442 and the third inclined surface 542 slide downward, a relatively large rightward force is applied to the second inclined surface 643, and a relatively large leftward force is applied to the fourth inclined surface 743. As a result, a force acts on the lower door 21 such that the vertical center surface F2 of the lower door 21 smoothly approaches the vertical center surface F1 of the main body 1.

[0076] Next, the rotation restriction function will be explained with reference to Figures 1 to 22. Figure 21 is a schematic diagram showing the state in which the tip 841 of the first stopper 84 shown in Figure 10 abuts against the tip 811 of the first stopper receiver 81 shown in Figure 6. Figure 22 is a schematic diagram showing the state in which the tip 841 of the first stopper 84 shown in Figure 6 is received by the second stopper receiver 82.

[0077] As shown in Figure 6, the lower opening / closing mechanism 31 is provided with a first stopper receiver 81, a second stopper receiver 82, and a first stopper contact portion 83 on the lower door guide portion 311. The first stopper receiver 81, the second stopper receiver 82, and the first stopper contact portion 83 are a single component with the first cam receiver 44 and are located radially away from the first hinge pin 42 in the direction of the first rotation axis A.

[0078] The first stopper receiver 81 has a tip portion 811 and an inner circumferential surface 812. The tip portion 811 is the end of the first stopper receiver 81 in the first separation direction D42. The tip portion 811 is located in a first restricting position, which is a distance of a first opening angle in the first separation direction D42 from the closed position of the lower door 21 (i.e., opening angle 0°). The first opening angle is approximately 120°. The tip portion 811 is located to the right of the first hinge pin 42 in the left-right direction D2. At this position, the tip portion 811 extends in the up-down direction D1.

[0079] The inner circumferential surface 812 is a curved surface that extends along the first approach direction D41 from the tip portion 811 to approximately in front of the first hinge pin 42. The inner circumferential surface 812 faces radially outward from the first rotation axis A1.

[0080] The first stopper receiver 81 is a groove defined by the tip portion 811 and the inner circumferential surface 812. The first stopper receiver 81 is recessed below the lower end of the first inclined surface 442 of the first cam receiver 44. The first stopper receiver 81 is also open upward, forward, and to the right.

[0081] The second stopper receiver 82 has an end portion 821. The end portion 821 is the end portion of the second stopper receiver 82 in the first separation direction D42. The end portion 821 is located at a second regulating position, which is a distance of a second opening angle from the first regulating position in the first separation direction D42. The second opening angle is several degrees.

[0082] The second stopper receiver 82 is located between the tip 811 of the first stopper receiver 81 and the lower end of the first inclined surface 442 in both the first separation direction D42 and the vertical direction D1. The second stopper receiver 82 is a groove extending from the end 821 in the first approach direction D41. The second stopper receiver 82 is open upward and forward.

[0083] The first stopper contact portion 83 is integral with the first stopper receiver 81 and is a single component. That is, the first stopper contact portion 83 and the first stopper receiver 81 are made of the same resin material as the first cam receiver 44. The first stopper contact portion 83 protrudes forward from a position to the right of the tip portion 811 of the first stopper receiver 81. The first stopper contact portion 83 faces the inner circumferential surface 812 in the left-right direction D2.

[0084] As shown in Figure 7, the lower opening / closing mechanism 31 is provided with a third stopper receiver 91, a fourth stopper receiver 92, and a second stopper contact portion 93 on the lower door guide portion 311. The third stopper receiver 91 is symmetrical to the first stopper receiver 81 in the left-right direction D6 with respect to the vertical center plane F2. The fourth stopper receiver 92 is symmetrical to the second stopper receiver 82 in the left-right direction D6 with respect to the vertical center plane F2. The second stopper contact portion 93 is symmetrical to the first stopper contact portion 83 in the left-right direction D6 with respect to the vertical center plane F2.

[0085] As shown in Figure 10, the lower opening / closing mechanism 31 includes a first stopper 84. The first stopper 84 is located to the left of the first guide groove 61 in the left-right direction D6 of the lower door 21. The first stopper 84 is located on the front surface 211 side of the lower door 21 relative to the first guide groove 61. The first stopper 84 extends in the left-right direction D6.

[0086] In detail, the first stopper 84 has a tip portion 841 and a side portion 842. The tip portion 841 extends in the vertical direction D1 at a position diagonally forward and to the left of the front end of the first guide groove 61. The side portion 842 extends from the tip portion 841 to the left in the horizontal direction D6 along the front surface 211 of the lower door 21.

[0087] As shown in Figure 9, the lower opening / closing mechanism 31 includes a second stopper 94. The second stopper 94 is symmetrical to the first stopper 84 in the left-right direction D6 with respect to the vertical center plane F2.

[0088] When the user opens the lower door 21 around the first rotation axis A1, a force is applied to the lower door 21 in the first separation direction D42 when it is in the closed position. Just before the opening angle of the lower door 21 reaches 120°, the tip 841 of the first stopper 84 enters the first stopper receiver 81. Subsequently, as shown in Figure 21, as the opening angle of the lower door 21 reaches 107°, the tip 841 abuts against the tip 811 of the first stopper receiver 81. Furthermore, as the opening angle of the lower door 21 increases by several degrees, the side surface 842 of the first stopper 84 abuts against the first stopper contact portion 83.

[0089] Incidentally, the refrigerator 100 may be used in a space where it is placed next to another refrigerator 100. In this embodiment, the lower door 21 does not rotate in the first separation direction D42 from the first restricted position during normal use. Therefore, the lower door 21 is prevented from colliding with the adjacent refrigerator 100. When the refrigerator 100 is installed next to a wall in the installation space, or when there is another door next to the lower door 21, it is preferable to limit the first restricted position (first opening angle) of the first stopper receiver 81 to approximately 90°.

[0090] Furthermore, depending on the operating environment of the refrigerator 100, it is conceivable that an unexpected force stronger than that during normal use may be applied to the lower door 21, resulting in the lower door 21 rotating from the first restricted position toward the first separation direction D42. For this reason, in this embodiment, a second stopper receiver 82 is provided. Specifically, when an unexpected force is applied to the lower door 21, as shown in Figure 22, the tip 841 of the first stopper 84 goes over the tip 811 of the first stopper receiver 81 and is received by the second stopper receiver 82.

[0091] Embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. The drawings schematically show each component in order to make them easy to understand, and the number of each component shown may differ from the actual number due to the convenience of drawing creation. Also, each component shown in the above embodiments is just an example and is not particularly limiting, and various modifications are possible without substantially departing from the effects of the present invention.

[0092] In this embodiment, the lower opening / closing mechanism 31 had an auto-closing function for the lower door 21, a centering function for the lower door 21, and a rotation restriction function for the lower door 21. However, it is not limited to this, and the lower opening / closing mechanism 31 only needs to have at least one function selected from the auto-closing function, the centering function, and the rotation restriction function.

[0093] In the embodiment, the first contact portion 63 included three rollers 631, 632, and 633, and the second contact portion 73 included three rollers 731, 732, and 733. It included multiple rollers. However, it is not limited to this, and each of the first contact portion 63 and the second contact portion 73 may be a projection covered with a resin that has excellent sliding properties.

[0094] In this embodiment, the refrigerator 100 was equipped with multiple opening / closing mechanisms 3. However, it is not limited to this, and the refrigerator 100 only needs to be equipped with at least one opening / closing mechanism 3.

[0095] In this embodiment, the first cam 64 had a first flat surface 641, a first inclined surface 642, and a second inclined surface 643. However, it is not limited to this configuration; the first cam 64 only needs to consist of at least one surface. The same applies to the second cam 74.

[0096] The first cam receiver 44 and the second cam receiver 54 are preferably separate components from the lower door guide portion 311 and are attached to the lower door guide portion 311 with screws or the like. The first cam 64 and the second cam 74 are also preferably separate components from the lower door 21 and are attached to the lower door 21 with screws or the like. Therefore, the first cam receiver 44, the second cam receiver 54, the first cam 64, or the second cam 74 can be replaced with new ones if they become worn or damaged.

[0097] Furthermore, the first cam receiver 44 and the second cam receiver 54 may be integrated with the lower door guide portion 311. The first cam 64 and the second cam 74 may be integrated with the lower door 21.

[0098] Furthermore, in the embodiment, with respect to the auto-close function, the lower opening / closing mechanism 31 was equipped with a lower door guide portion 311, a plurality of first contact portions 63, and a plurality of second contact portions 73. However, the lower opening / closing mechanism 31 is not limited to this, and does not need to be equipped with a lower door guide portion 311, a plurality of first contact portions 63, and a plurality of second contact portions 73. That is, with respect to the auto-close function, the lower opening / closing mechanism 31 only needs to be equipped with at least a first cam receiver 44, a first cam 64, a second cam receiver 54, and a second cam 74. [Industrial applicability]

[0099] This invention can be used as a refrigerator, freezer, or the like. [Explanation of Symbols]

[0100] 100 Refrigerator 1 Main unit 11 Lower Confinement Room 112 Lower edge 2 doors 21 Lower door 211 Front 212 Bottom surface 213 Rear 3. Opening and closing mechanism 3111 First guide surface 3112 Second guide surface 42. First hinge pin 44 First cam receiver 441 1st flat surface 442 1st slope 443 2nd slope 52. Second hinge pin 54. Second cam receiver 541 2nd flat surface 542 Third slope 543 4th slope 61 First guide groove 63 1st contact part 64 First Cam 71 Second guide groove 73 Second contact part 74 Second Cam 81. First stopper receiver 82. Second stopper receiver 83 First stopper contact section 84 First Stopper 841 Tip 842 Side view 91 Third stopper receiver 92. Fourth stopper receiver 93 Second stopper contact section 94 Second Stopper

Claims

1. A door opening and closing mechanism for opening and closing an opening in the main body, The door is connected to the main body by a first hinge pin so as to be rotatable in the circumferential direction of the first rotation axis, A door guide portion having a first guide surface that inclins upward from below the opening toward the front of the main body, The door has a first contact portion located away from the first rotation axis and capable of contacting the first guide surface, The door has a first cam located closer to the first rotation axis than the first contact portion and protruding downward from the door, The main body has a first cam receiver formed in an arc shape at a position away from the first rotation axis, on which the first cam can slide. Equipped with, The circumferential direction includes a first approaching direction toward the opening and a first moving away direction opposite to the first approaching direction. The first cam receiver is, A first flat surface extending approximately horizontally, The first flat surface has a first inclined surface that slopes downward toward the first approach direction from the end of the first approach direction, In the process in which the door rotates in the first approaching direction to close the opening, When the first cam slides on the first flat surface, the first contact portion rotates in the first approach direction at a position above the first guide surface. An opening and closing mechanism in which the first contact portion contacts the first guide surface when the first cam slides on the first inclined surface.

2. The door guide portion has a second guide surface that slopes downward toward the front from the front end of the first guide surface, The first cam receiver has a second inclined surface that slopes downward toward the first separation direction from the end of the first flat surface in the first separation direction, The opening and closing mechanism according to claim 1, wherein, in the process of the door rotating in the first approaching direction to close the opening, the first cam slides on the second inclined surface and the first flat surface, and the first contact portion rotates in the first approaching direction at a position above the second guide surface.

3. A second hinge pin connects the door to the main body so that it can rotate, in the circumferential direction of a second rotation axis that is separated from the first rotation axis in the left-right direction of the main body, A first guide groove supports the first hinge pin when the door rotates in the circumferential direction of the first rotation axis, and guides the first hinge pin when the door rotates in the circumferential direction of the second rotation axis, A second guide groove supports the second hinge pin when the door rotates in the circumferential direction of the second rotation axis, and guides the second hinge pin when the door rotates in the circumferential direction of the first rotation axis, The door has a second contact portion located between the first contact portion and the second rotation axis, which is capable of contacting the first guide surface, In the aforementioned door, a second cam is located closer to the second rotation axis than the second contact portion and protrudes downward, The main body is formed in an arc shape at a position away from the second rotation axis, and the second cam is slidable on the second cam and Equipped with, The circumferential direction of the second rotation axis includes a second approaching direction toward the opening and a second moving away direction opposite to the second approaching direction, The second cam receiver is, A second flat surface extending almost horizontally, A third inclined surface that slopes downward toward the second approach direction from the end of the second flat surface in the second approach direction, A fourth inclined surface that slopes downward toward the second separation direction from the end of the second flat surface in the second separation direction and It has, In the process in which the door rotates in the second approaching direction to close the opening, As the second cam slides on the second flat surface, the second contact portion rotates in the second approach direction at a position above the first guide surface. When the second cam slides on the third inclined surface, the second contact portion contacts the first guide surface. As the door rotates in the first approaching direction in the circumferential direction of the first rotation axis to close the opening, the first contact portion is located above the first guide surface at the position where the second guide groove begins to guide the second hinge pin, and thereafter, as the door rotates in the first approaching direction, the first contact portion and the second contact portion come into contact with the first guide surface. The opening and closing mechanism according to claim 1 or 2, wherein, in the process of the door rotating in the second approach direction in the circumferential direction of the second rotation axis to close the opening, the second contact portion is located above the first guide surface at the position where the first guide groove begins to guide the first hinge pin, and thereafter, when the door rotates in the second approach direction, the first contact portion and the second contact portion come into contact with the first guide surface.

4. The width of the first guide groove is greater than the outer diameter of the first hinge pin. The width of the second guide groove is greater than the outer diameter of the second hinge pin. When the door rotates in the circumferential direction of one of the first and second rotation axes to close the opening, When the first cam contacts the first inclined surface, the first inclined surface applies a force to the first cam that includes a component in one of the left-right directions and an outward component of the main body. The opening and closing mechanism according to claim 3, wherein the second cam contacts the third inclined surface, thereby applying a force to the second cam that includes a component representing the other of the left-right directions and an outward component of the main body.

5. The first inclined surface is a curved surface in which the lower portion of the first inclined surface faces outward from the main body more than the upper portion of the first inclined surface. The opening and closing mechanism according to claim 4, wherein the third inclined surface is a curved surface in which the lower portion of the third inclined surface faces outward from the main body more than the upper portion of the third inclined surface.

6. A door opening and closing mechanism for opening and closing an opening in the main body, The door is connected to the main body by a first hinge pin so as to be rotatable in the circumferential direction of the first rotation axis, A door guide portion having a first guide surface that inclins upward from below the opening toward the front of the main body, The door comprises a first contact portion located away from the first rotation axis and capable of contacting the first guide surface, The circumferential direction includes a first approaching direction toward the opening and a first moving away direction opposite to the first approaching direction. The door includes a stopper positioned away from the first rotation axis and protruding downward from the door, The door is provided at a first restricting position located away from the closed position that closes the opening in the first separation direction, and a first stopper receiver that receives the tip of the stopper in the first separation direction, In response to the tip of the stopper coming into contact with the first stopper receiver, the side of the stopper extending along the front surface of the door comes into contact with the stopper contact portion. An opening and closing mechanism.

7. The opening and closing mechanism according to claim 6, wherein the first stopper receiver and the stopper contact portion are configured as a single flexible member.

8. The opening and closing mechanism according to claim 6, further comprising a second stopper receiver provided at a second restricting position located at a distance from the upper end of the first stopper receiver in the first separation direction, and receiving the tip of the stopper.

9. A door opening and closing mechanism for opening and closing an opening in the main body, The door is connected to the main body by a first hinge pin so as to be rotatable in the circumferential direction of the first rotation axis, The door is connected to the main body by a second hinge pin that allows it to rotate circumferentially on a second rotation axis, which is located away from the first rotation axis in the left-right direction of the main body, A first guide groove supports the first hinge pin when the door rotates in the circumferential direction of the first rotation axis, and guides the first hinge pin when the door rotates in the circumferential direction of the second rotation axis, A second guide groove supports the second hinge pin when the door rotates in the circumferential direction of the second rotation axis, and guides the second hinge pin when the door rotates in the circumferential direction of the first rotation axis, A door guide portion having a first guide surface that inclins upward from below the opening toward the front of the main body, The door has a first contact portion located away from the first rotation axis and capable of contacting the first guide surface, The door has a second contact portion located between the first contact portion and the second rotation axis, which is capable of contacting the first guide surface, The door has a first cam located closer to the first rotation axis than the first contact portion and protruding downward from the door, The main body includes a first cam receiver formed in an arc shape at a position away from the first rotation axis, on which the first cam can slide, In the aforementioned door, a second cam is located closer to the second rotation axis than the second contact portion and protrudes downward, The main body is formed in an arc shape at a position away from the second rotation axis, and the second cam is slidable on the second cam and Equipped with, The circumferential direction of the first rotation axis includes a first approaching direction toward the opening and a first moving away direction opposite to the first approaching direction, The circumferential direction of the second rotation axis includes a second approaching direction toward the opening and a second moving away direction opposite to the second approaching direction, The first cam receiver is, A first flat surface extending approximately horizontally, A first inclined surface that slopes downward toward the first approach direction from the end of the first flat surface in the first approach direction, It has, The second cam receiver is, A second flat surface extending almost horizontally, A third inclined surface that slopes downward toward the second approach direction from the end of the second flat surface in the second approach direction, It has, An opening and closing mechanism in which, when the door rotates in the circumferential direction of one of the first and second rotation axes to close the opening, the first cam contacts the first inclined surface and the second cam contacts the third inclined surface.

10. A refrigerator comprising the opening and closing mechanism described in any one of claims 1, 6, or 9.

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