Washing timer capable of preventing arc discharge

Abstract

The utility model provides an anti-arcing washing timer, which is characterized in that a reed group comprises a first reed positioned on the inner side and a second reed positioned on the outer side, both the first reed and the second reed are provided with contacts, a cam is provided with gear teeth, the gear teeth comprise inner gear teeth and outer gear teeth, the first reed is always elastically propped against the inner gear teeth, and the second reed is always elastically propped against the outer gear teeth. The second reed has the trend of always abutting against the outer gear teeth, the inner gear teeth and the outer gear teeth each comprise a tooth back side and a tooth end face, the tooth back side is a curved surface with the radius gradually increased, the tooth end face extends from the tail end of the tooth back side to the center direction of the cam, the radius of the tooth end face changes suddenly, and the contact is switched between the contact state and the disconnection state along with rotation of the cam. In the pair of reed groups of the washing timer, the two reeds can move along with the rotation of the cam, so that the disconnection and contact of the contacts can be quickly completed, the duration of sparks and arcing generated during the contact and disconnection of the contacts is short, the ablation process of the contacts is slowed down, and the service life of the product is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of household appliance technology, specifically to a washing timer with anti-arc properties. Background Technology

[0002] Washing machines are usually equipped with a washing timer, which mainly controls the washing motor to drive the washing impeller to rotate intermittently in the forward and reverse directions, thereby controlling the water flow and its rotation time to achieve the corresponding washing effect.

[0003] Due to their reliable performance, spring-loaded timers are widely used in household appliances. Washing timers for washing machines often employ this type of timer, as illustrated in patents 201320268384.6 (authorization announcement number CN203288498U) and 200620103069.8 (authorization announcement number CN2901556Y). This type of washing timer uses two pairs of spring contacts that elastically abut against a cam, achieving intermittent forward and reverse rotation of the washing machine through the contact and disconnection of these contacts. Specifically, each pair of reeds includes a movable reed on the outer side and a stationary reed on the inner side. The stationary reed has a stationary contact riveted to it and is laterally limited by a stop post on the base. The movable reed has a movable contact riveted to it. The movable reed elastically abuts against the cam. The cam has multiple teeth, each tooth having a tooth back side and a tooth end face. The tooth back side is a curved surface with a gradually increasing radius. The movable reed moves when the cam rotates, realizing the contact and disconnection of the contacts. That is, when the movable reed abuts against the tooth back side, the movable contact and the stationary contact disconnect as the radius of the tooth back side increases, and the movable contact gradually moves away from the stationary contact. When the cam rotates to the tooth end face, due to the sudden change in radius, the movable contact moves towards the stationary contact and makes contact.

[0004] However, the aforementioned washing timer has the following problems: When the cam rotates, due to the gradual increase in the radius of the tooth back side and the sudden change in the radius of the tooth end face, only the contact process between the moving contact and the stationary contact is completed quickly during the operation of the moving spring, while the disconnection process between the moving contact and the stationary contact can only be completed slowly. During this disconnection process, the sparks and arcs generated between the moving contact and the stationary contact last for a long time. This not only causes premature burning failure of its own contacts and shortens the product's service life, but also causes excessive electromagnetic interference to surrounding electronic equipment, making the product unable to pass electromagnetic compatibility (EMC) compliance testing.

[0005] In conclusion, the existing washing timers still need improvement. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a washing timer that avoids sparks and arcing between contacts during use, in light of the above-mentioned existing technology.

[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problem is as follows: the anti-arc washing timer includes a housing, and a spring group and a cam installed in the housing. The spring group and the cam elastically abut against each other. The spring group includes a first spring on the inner side and a second spring on the outer side. Both the first spring and the second spring are provided with contact points. The cam is provided with at least two gear teeth, including inner gear teeth and outer gear teeth. The first spring always elastically abuts against the inner gear teeth, and the second spring tends to always abut against the outer gear teeth. The inner gear teeth and the outer gear teeth are offset by a first preset angle α along the rotation direction of the cam. Both the inner gear teeth and the outer gear teeth include a tooth back side and a tooth end face. The tooth back side is a curved surface with a gradually increasing radius. The tooth end face extends from the end of the tooth back side towards the center of the cam and the radius changes abruptly. The contact points switch between a contact state and a disconnected state as the cam rotates.

[0008] To enable the contact point to switch between an engaged and disengaged state as the cam rotates, preferably, the inner and outer gear teeth are distributed on two different circumferences of the cam. The back side of the inner gear teeth includes a first inner gear tooth segment connected to the tooth end face of the inner gear tooth and a second inner gear tooth segment connected to the tooth end face of the adjacent inner gear tooth. The back side of the outer gear teeth includes a first outer gear tooth segment connected to the tooth end face of the outer gear tooth and a second outer gear tooth segment connected to the tooth end face of the adjacent outer gear tooth. The first inner gear tooth segment and the corresponding second outer gear tooth segment have the same radius. The height H1 of the tooth end face of the outer gear tooth is greater than the height H2 of the tooth end face of the inner gear tooth. Since the first inner gear tooth segment and the corresponding second outer gear tooth segment have the same radius, when the first spring abuts against this segment, only the first spring abuts against the inner gear tooth, and the contact point of the second spring is in contact with the contact point of the first spring. As the cam rotates, the first spring first rotates to the tooth end face of the inner gear tooth and moves inward with the sudden change in the radius of the tooth end face, causing the contact point to break. At this time, the second spring loses the support of the first spring and moves inward to abut against the outer gear tooth. The cam continues to rotate, and the contact point is in the open state during this rotation process. When the second spring rotates to the tooth end face of the outer gear tooth, it moves inward with the sudden change in the radius of the tooth end face, and the contact points of the two springs come into contact with each other. The height H1 of the tooth end face of the outer gear tooth is greater than the height H2 of the tooth end face of the inner gear tooth, which ensures that the contact points of the two springs are in the open state when both the first spring and the second spring abut against their respective corresponding gear teeth.

[0009] As a solution to achieve the same radius for the first inner gear tooth segment and the corresponding second outer gear tooth segment, preferably, the back sides of the inner and outer gear teeth are cut from the side of the same cylinder, and the cylinder is not coaxial with the cam.

[0010] To enable rapid contact and disconnection of the contacts, preferably, the tooth end faces of both the outer and inner gear teeth are arranged radially along the cam. Thus, when the first or second spring moves to the tooth end face as the cam rotates, it can instantly move inward under the elastic action of the spring, thereby minimizing the duration of sparks and arcs generated during contact and disconnection.

[0011] Preferably, both the inner and outer gear teeth are evenly distributed along the circumference of the cam. This even distribution ensures the stability of the washing timer during operation and guarantees the consistency of each cycle time.

[0012] To facilitate the first spring contacting the inner gear teeth and the second spring contacting the outer gear teeth, preferably, the end of the first spring is provided with a first contact portion, and the contact point on the first spring is located adjacent to the first contact portion, and the first contact portion always contacts the inner gear teeth; the end of the second spring is provided with a second contact portion, and the contact point on the second spring is located adjacent to the second contact portion, and the second contact portion always tends to contact the outer gear teeth.

[0013] To enable the washing machine to rotate forward and reverse under the control of the washing timer, preferably, the reed assembly has two pairs, including a forward rotation reed assembly for controlling the forward rotation of the washing machine and a reverse rotation reed assembly for controlling the reverse rotation of the washing machine. Correspondingly, two cams are also provided. The forward rotation reed assembly and the reverse rotation reed assembly elastically abut against their respective cams, allowing the contacts on the forward rotation reed assembly and the reverse rotation reed assembly to alternately switch between a contact state and an open state. Thus, when the contacts of the forward rotation reed assembly are in the contact state, the washing machine rotates forward; when the contacts of the reverse rotation reed assembly are in the contact state, the washing machine rotates in reverse. The contacts on the forward rotation reed assembly and the reverse rotation reed assembly alternately contact and open, thereby realizing the alternating forward and reverse rotation of the washing machine.

[0014] To achieve alternating contact and disconnection of the contacts on the forward and reverse spring groups, preferably, the two cams are mirror images of each other, and the teeth on the two cams are offset by a second preset angle β along the rotation direction of the cams. Since the washing machine needs to alternate between forward and reverse rotation, when the contacts of the forward spring group are in contact, the contacts of the reverse spring group must be disconnected, and vice versa. Therefore, by mirroring the cams corresponding to the two pairs of spring groups and offsetting them by a second preset angle β, when the second spring of the forward spring group moves rapidly inward and makes the contacts of the forward spring group contact each other, the first spring of the reverse spring group moves rapidly inward and makes the contacts of the reverse spring group disconnect, causing the washing machine to rotate forward. When the first spring of the forward spring group moves rapidly inward and makes the contacts of the forward spring group disconnect, the second spring of the reverse spring group moves rapidly inward and makes the contacts of the reverse spring group contact each other, causing the washing machine to rotate in reverse.

[0015] Compared with the prior art, the advantages of this utility model are as follows: In the pair of reeds of this washing timer, both reeds can move with the rotation of the cam. Since the inner and outer gear teeth are offset by a first preset angle α along the rotation direction of the cam, when the first reed located on the inner side rotates along the inner gear tooth to the tooth end face, the first reed moves rapidly inward due to the sudden change in the radius of the tooth end face, causing the contacts on the two reeds to quickly disconnect. As the cam rotates, both the first and second reeds abut against their respective gear teeth and move outward as the radius of the tooth back side gradually increases, until the second reed rotates along the inner gear tooth... When the first spring reaches the tooth end face, it moves rapidly inward due to the sudden change in the radius of the tooth end face, causing the contacts on the two springs to make contact quickly. The process of contact opening and closing is completed quickly, avoiding the defect of slow contact opening caused by only one side of the spring moving while the other side is fixed and stationary in the existing structure. This results in a shorter duration of sparks and arcs generated when the contacts are made and closed. This not only slows down the ablation process of the contacts themselves and extends the product's service life, but also avoids causing excessive electromagnetic interference to surrounding electronic equipment and can pass electromagnetic compatibility (EMC) compliance tests. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0017] Figure 2 This is a schematic diagram of the reed assembly and cam in an embodiment of this utility model;

[0018] Figure 3 This is a schematic diagram of the forward rotation spring assembly in an embodiment of the present invention;

[0019] Figure 4 A schematic diagram of the cam structure in the embodiment of this utility model is provided;

[0020] Figure 5 This is a schematic diagram of the meshing relationship between the two cams in an embodiment of this utility model;

[0021] Figure 6 This is a schematic diagram showing the state in which the contacts of both the forward and reverse rotating spring groups are open in an embodiment of this utility model;

[0022] Figure 7 This is a schematic diagram showing the state in which the contacts of the forward-rotating reed group are open and the contacts of the reverse-rotating reed group are in contact, as described in this utility model embodiment.

[0023] Figure 8 This is a schematic diagram showing the state in which the contacts of the forward-rotating spring group are in contact and the contacts of the reverse-rotating spring group are out of contact in an embodiment of this utility model. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1-8 The figure shown is a preferred embodiment of the present invention.

[0026] See Figure 1-2 The anti-arc washing timer of this embodiment includes a housing 1 and a reed assembly 2 and a cam 3 installed inside the housing 1. For washing programs such as strong wash and gentle wash, each program has two pairs of reed assemblies 2: a forward-rotating reed assembly 21 that controls the forward rotation of the washing machine and a reverse-rotating reed assembly 22 that controls the reverse rotation. Correspondingly, there are also two cams 3. The forward-rotating reed assembly 21 and the reverse-rotating reed assembly 22 elastically abut against their respective cams 3. The forward-rotating reed assembly 21 and the reverse-rotating reed assembly 22 have the same structure. This embodiment only uses the forward-rotating reed assembly 21 and the cam 3 that elastically abuts against it as an example to illustrate the structure of the reed assembly 2 and the cam 3. See details. Figure 3 Each pair of reeds 2 includes a first reed 211 located on the inner side and a second reed 212 located on the outer side. The end of the first reed 211 is provided with a first abutting part 211a, and the end of the second reed 212 is provided with a second abutting part 212a. The first reed 211 is provided with a contact point 23 near the first abutting part 211a and the second reed 212 is provided with a contact point 23 near the second abutting part 212a. In this embodiment, the cam 3 has three teeth evenly distributed on it. The teeth include an inner tooth 31 and an outer tooth 32. The first abutting part 211a always abuts against the inner tooth 31, and the second abutting part 212a always tends to abut against the outer tooth 32.

[0027] See Figure 4The inner gear tooth 31 and the outer gear tooth 32 of the cam 3 both include a tooth back side 301 and a tooth end face 302. The tooth back side 301 is a curved surface with a gradually increasing radius. The tooth end face 302 extends from the end of the tooth back side 301 toward the center of the cam 3 and the radius changes abruptly. The tooth end faces 302 of the inner gear tooth 31 and the outer gear tooth 32 are both arranged along the radial direction of the cam 3. The inner gear tooth 31 and the outer gear tooth 32 are offset by a first preset angle α along the rotation direction of the cam 3. The contact points 23 located on the two springs switch between the contact state and the disconnected state as the cam 3 rotates. Specifically, the inner gear teeth 31 and the outer gear teeth 32 are distributed on two different circumferences of the cam 3. The tooth back side 301 of the inner gear teeth 31 includes a first inner gear tooth segment 31a connected to the tooth end face 302 of the inner gear teeth 31 and a second inner gear tooth segment 31b connected to the tooth end face 302 of the adjacent inner gear teeth 31. The tooth back side 301 of the outer gear teeth 32 includes a first outer gear tooth segment 32a connected to the tooth end face 302 of the outer gear teeth 32 and a second outer gear tooth segment 32b connected to the tooth end face 302 of the adjacent outer gear teeth 32. The first inner gear tooth segment 31a and the second outer gear tooth segment 32b at the corresponding positions have the same radius. When the washing timer is working, when the first contact portion 211a of the first reed 211 abuts against the first inner gear tooth segment 31a of the inner gear tooth 31, the contact point 23 of the first reed 211 contacts the contact point 23 of the second reed 212. Due to the limiting effect of the first reed 211 located on the inner side on the second reed 212 located on the outer side, the second contact portion 212a of the second reed 212 has a tendency to abut against the second outer gear tooth segment 32b of the outer gear tooth 32 without contacting the second outer gear tooth segment 32b. When the first contact portion 211a rotates along the inner gear tooth 31 to the tooth end face 302, the first contact portion 211a moves rapidly inward due to the sudden change in the radius of the tooth end face 302. The second reed 212, due to the loss of the limiting effect of the first reed 211, also moves its second contact portion 212a inward. Due to the change in the radius of the inner gear tooth 31 and the outer gear tooth 31a, the second contact portion 212a moves inward. 2. When the two springs are offset by a first preset angle α, the second contact part 212a contacts the first outer gear tooth segment 32a. As the radius of the tooth back side 301 gradually increases, the distance the second spring 212 moves inward is less than the distance the first spring 211 moves inward. Therefore, the contact points 23 of the two springs are disconnected and the disconnection process is completed quickly, so that the sparks and arcs generated when the contact points 23 are in contact and disconnected last for a short time. The cam 3 continues to rotate, the first contact part 211a contacts the second inner gear tooth segment 31b, the second contact part 212a contacts the first outer gear tooth segment 32a, and the contact points 23 of the two springs are in the disconnected state. When the second contact part 212a rotates along the outer gear tooth 32 to the tooth end face 302, the second contact part 212a moves inward quickly due to the sudden change in the radius of the tooth end face 302, and the contact points 23 of the two springs come into contact with each other.Furthermore, to ensure that the contact points 23 of the two springs are in an open state when the first contact portion 211a abuts against the second inner gear tooth segment 31b and the second contact portion 212a abuts against the first outer gear tooth segment 32a, the height H1 of the tooth end face 302 of the outer gear tooth 32 is designed to be greater than the height H2 of the tooth end face 302 of the inner gear tooth 31. As a gear tooth structure, in this embodiment, the tooth back sides 301 of the inner gear tooth 31 and the outer gear tooth 32 are cut from the side of the same cylinder, and this cylinder is not coaxial with the cam 3.

[0028] To achieve alternating forward and reverse rotation of the washing machine, the cams 3 corresponding to the forward rotation spring group 21 and the reverse rotation spring group 22 are mirror images of each other, and the gear teeth on the two cams 3 are offset by a second preset angle β along the rotation direction of the cams 3. (See figure) Figure 5 The washing machine rotates in the forward rotation spring group 21 and the reverse rotation spring group 22, allowing the contacts 23 on the forward rotation spring group 21 and the reverse rotation spring group 22 to alternately switch between a contact state and an open state. Specifically, when the second spring 212 of the forward rotation spring group 21 moves rapidly inward and makes the contacts 23 of the forward rotation spring group 21 contact each other, the first spring 211 of the reverse rotation spring group 22 moves rapidly inward and makes the contacts 23 of the reverse rotation spring group 22 open, causing the washing machine to rotate in the forward direction. When the first spring 211 of the forward rotation spring group 21 moves rapidly inward and makes the contacts 23 of the forward rotation spring group 21 open, the second spring 212 of the reverse rotation spring group 22 moves rapidly inward and makes the contacts 23 of the reverse rotation spring group 22 contact each other, causing the washing machine to rotate in the reverse direction. This achieves alternating forward and reverse rotation of the washing machine.

[0029] To enable the contacts 23 on the forward-rotating spring group 21 and the reverse-rotating spring group 22 to alternately switch between contact and open states, in this embodiment, the second preset angle β is 60°, that is: the inner gear tooth 31 of the cam 3 corresponding to the forward-rotating spring group 21 corresponds to the outer gear tooth 32 of the cam 3 corresponding to the reverse-rotating spring group 22, and the outer gear tooth 32 of the cam 3 corresponding to the forward-rotating spring group 21 corresponds to the inner gear tooth 31 of the cam 3 corresponding to the reverse-rotating spring group 22. However, when the washing machine alternates between forward and reverse rotation, it generates a large instantaneous current and mechanical shock, which puts a large load on the motor. At the same time, the inertia of the impeller or drum is large during its rotation. To avoid damage to the washing machine caused by instantaneous reverse rotation, this embodiment designs a stop state in which the contacts 23 of both pairs of spring groups 2 are not in contact before the contacts 23 of the forward-rotating spring group 21 and the contacts 23 of the reverse-rotating spring group 22 come into contact with each other. See details. Figure 6In this embodiment, the second contact portion 212a of the second spring 212 is longer than the first contact portion 211a of the first spring 211. When the first contact portion 211a of the first spring 211 of the reverse spring group 22 moves inward at the tooth end face 302 and disconnects the contact point 23 of the reverse spring group 22, because the second contact portion 212a is longer, the second contact portion 212a of the second spring 212 of the forward spring group 21 still abuts against the tooth back side 301. That is, the contact point 23 of the forward spring group 21 is still in the open state. The cam 3 needs to rotate a certain angle before the second contact portion 212a rotates to the tooth end face 302 and moves inward to make the contact point 23 of the forward spring group 21 contact, and the washing machine switches to forward rotation. During this certain angle rotation time, the contact points 23 of both the forward spring group 21 and the reverse spring group 22 are in the open state, that is, the washing machine is in the stopped state. The same applies to switching from forward to reverse rotation.

[0030] In summary, one working cycle of the washing timer in this embodiment is as follows:

[0031] See Figure 7 In the reverse rotation spring assembly 22, the first contact portion 211a of the first spring 211 abuts against the first inner gear tooth segment 31a of the inner gear tooth 31, the first spring 211 limits the second spring 212 and the contact points 23 of the two springs are in contact; in the forward rotation spring assembly 21, the first contact portion 211a of the first spring 211 abuts against the second inner gear tooth segment 31b of the inner gear tooth 31, the second contact portion 212a of the second spring 212 abuts against the first outer gear tooth segment 32a of the outer gear tooth 32, the contact points 23 of the two springs of the forward rotation spring assembly 21 are disconnected, and the washing machine reverses in this state;

[0032] See Figure 2 and Figure 6 As the cam 3 rotates, the first contact portion 211a of the first spring 211 of the reverse spring assembly 22 rotates to the tooth end face 302 and moves inward due to the sudden change in the radius of the tooth end face 302, causing the contact points 23 of the two springs to disconnect; the first contact portion 211a of the first spring 211 of the forward spring assembly 21 abuts against the first inner gear tooth segment 31a of the inner gear tooth 31, and the second contact portion 212a of the second spring 212 still abuts against the contact point 23 of the first outer gear tooth segment 32a of the outer gear tooth 32 in the disconnected state, in which the washing machine stops rotating;

[0033] See Figure 8As the cam 3 continues to rotate, the first contact portion 211a of the first spring 211 of the forward-rotating spring assembly 21 abuts against the first inner gear tooth segment 31a of the inner gear tooth 31, and the second contact portion 212a of the second spring 212 rotates to the tooth end face 302 and moves inward due to the sudden change in the radius of the tooth end face 302, so that the contact points 23 of the two springs come into contact; the first contact portion 211a of the first spring 211 of the reverse-rotating spring assembly 22 abuts against the second inner gear tooth segment 31b of the inner gear tooth 31, and the second contact portion 212a of the second spring 212 abuts against the first outer gear tooth segment 32a of the outer gear tooth 32, and the contact points 23 of the reverse-rotating spring assembly 22 are in the open state, in which the washing machine rotates forward.

[0034] To meet the needs of different washing programs in a washing machine, simply increase or decrease the number of teeth in the cam 3 that controls the program. For example, for a strong wash program, design two teeth to increase the time for forward and reverse rotation in one cycle; for a gentle wash program, design four teeth to decrease the time for forward and reverse rotation in one cycle. Of course, the number of teeth can also be designed to meet other requirements.

[0035] It should be noted that in the description of this embodiment, the terms "front," "rear," "left," "right," "inner," "outer," "upper," and "lower," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

Claims

1. A wash timer with anti-arc function, comprising a housing (1), and a reed assembly (2) and a cam (3) installed within the housing (1), wherein the reed assembly (2) and the cam (3) elastically abut against each other, characterized in that: The reed assembly (2) includes a first reed (211) located on the inner side and a second reed (212) located on the outer side. Both the first reed (211) and the second reed (212) are provided with contact points (23). The cam (3) is provided with at least two gear teeth, including inner gear teeth (31) and outer gear teeth (32). The first reed (211) always elastically abuts against the inner gear teeth (31), and the second reed (212) tends to always abut against the outer gear teeth (32). The inner gear teeth (31) and the outer gear teeth (32) are offset by a first preset angle α along the rotation direction of the cam (3). The inner gear teeth (31) and the outer gear teeth (32) each include a tooth back side (301) and a tooth end face (302). The tooth back side (301) is a curved surface with a gradually increasing radius. The tooth end face (302) extends from the end of the tooth back side (301) toward the center of the cam (3) and the radius changes abruptly. The contact point (23) switches between a contact state and a disconnected state as the cam (3) rotates.

2. The wash timer according to claim 1, characterized in that: The inner gear teeth (31) and outer gear teeth (32) are distributed on two different circumferences of the cam (3). The tooth back side (301) of the inner gear teeth (31) includes a first inner gear tooth segment (31a) connected to the tooth end face (302) of the inner gear teeth (31) and a second inner gear tooth segment (31b) connected to the tooth end face (302) of the adjacent inner gear teeth (31). The tooth back side (301) of the outer gear teeth (32) includes a first inner gear tooth segment (31a) connected to the tooth end face (302) of the outer gear teeth (31) and a second inner gear tooth segment (31b) connected to the tooth end face (302) of the adjacent inner gear teeth (31). The tooth end face (302) of the gear tooth (32) is connected to the first outer gear tooth segment (32a) and the tooth end face (302) of the adjacent outer gear tooth (32) is connected to the second outer gear tooth segment (32b). The first inner gear tooth segment (31a) and the corresponding second outer gear tooth segment (32b) have the same radius. The height H1 of the tooth end face (302) of the outer gear tooth (32) is greater than the height H2 of the tooth end face (302) of the inner gear tooth (31).

3. The wash timer according to claim 2, characterized in that: The back sides (301) of the inner gear teeth (31) and the outer gear teeth (32) are cut off from the side of the same cylinder, and the cylinder is not coaxial with the cam (3).

4. The wash timer according to claim 2, wherein: The tooth end faces (302) of both the outer gear teeth (32) and the inner gear teeth (31) are arranged along the radial direction of the cam (3).

5. The wash timer according to claim 2, wherein: The inner gear teeth (31) and outer gear teeth (32) are evenly distributed along the circumference of the cam (3).

6. The wash timer according to claim 1, characterized in that: The first reed (211) has a first abutting part (211a) at its end, and a contact point (23) on the first reed (211) is disposed adjacent to the first abutting part (211a). The first abutting part (211a) always abuts against the inner gear tooth (31). The second reed (212) has a second abutting part (212a) at its end, and a contact point (23) on the second reed (212) is disposed adjacent to the second abutting part (212a). The second abutting part (212a) always tends to abut against the outer gear tooth (32).

7. The wash timer according to claim 1, characterized in that: The reed assembly (2) has two pairs, including a forward reed assembly (21) for controlling the forward rotation of the washing machine and a reverse reed assembly (22) for controlling the reverse rotation of the washing machine. Correspondingly, the cam (3) is also provided in two. The forward reed assembly (21) and the reverse reed assembly (22) elastically abut against their respective cams (3), so that the contacts (23) on the forward reed assembly (21) and the reverse reed assembly can alternately switch between the contact state and the disconnected state.

8. The wash timer according to claim 7, characterized in that: The two cams (3) are arranged in a mirror image and the teeth on the two cams (3) are offset by a second preset angle β along the rotation direction of the cams (3).

Images