JP2017221594A - Self-traveling electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-traveling electronic apparatus having a suspension mechanism of which pressing force against the floor surface does not decrease even when drive wheels project further below a main body.SOLUTION: The self-traveling electronic apparatus comprises: the drive wheels; a drive unit driving the drive wheels for self-traveling; and the suspension mechanism carrying the drive wheels so as to be vertically displaceable. The suspension mechanism includes: an engagement part rotating about the shaft center depending on the displacement of the drive wheels and engaging an energizing member at a predetermined distance from the shaft center; and the energizing member engaging the engagement part and forcing the drive wheels to displace toward the lower end. The angle formed between a line extending from the engagement part toward the shaft center and the energizing direction of the energizing member gradually increases within a range of 90° or less even when the energizing force gradually decreases as the drive wheels displace from the upper end toward the lower end, so that the energizing force of the energizing member and the position of the engagement part are selected for increasing the component force of the biasing force which displaces the drive wheels toward the lower end.SELECTED DRAWING: Figure 5B

Description

  The present invention relates to a self-propelled electronic device including a floor surface detection sensor.

  An autonomous traveling type electric vacuum cleaner that cleans the floor surface while autonomously traveling on the floor surface while detecting an obstacle using a sensor, a so-called cleaning robot is known (for example, described in Patent Document 1). See vacuum cleaner). In addition to the cleaning robot, there are known robots that autonomously run to perform tasks such as indoor air cleaning, security on the premises, and transportation of luggage. In this specification, these devices having an autonomous running function are called self-propelled electronic devices.

  A self-propelled cleaner performs cleaning while self-propelled on an indoor floor surface. However, when there is a stepped portion on the floor surface, it becomes difficult to ride when the stepped portion becomes higher than a certain height. For example, there are a stepped portion between a floor surface and a carpet laid on the floor, a stepped portion by a sill that partitions the room, a stepped portion by a tatami partially laid on the flooring, and the like. If the self-propelled vacuum cleaner has a low step-over performance, the front part of the bottom of the housing (main body) rides on the step when stepping over the step, and the drive wheel floats from the floor and idles. There are cases where the traveling vacuum cleaner cannot move. If it is going to avoid falling into this state, a self-propelled cleaner must detect even a low level difference part as an obstacle, and must design so that it may run avoiding the level difference part. However, this causes a contradiction that the area beyond the stepped portion is not cleaned.

  In order to achieve a high step-over performance, the self-propelled cleaners in Patent Documents 1 and 2 are such that the left and right drive wheels can move up and down and each drive wheel is pressed against the floor surface by the elastic biasing force of the spring, It is configured to prevent lifting from the floor. Specifically, a drive wheel, a holder for rotatably holding the drive wheel, a motor attached to the holder, and a rotational force transmission mechanism provided in the holder so as to transmit the rotational force of the motor to the drive wheel are provided. A pair of drive wheel units are provided on the left and right sides of the bottom of the housing.

Japanese Patent Application Laid-Open No. 2012-125652 JP 2014-138899 A

The self-propelled electronic devices such as the self-propelled cleaners of Patent Documents 1 and 2 contact with the floor surface when the left and right drive wheels are displaced downward from the main body rather than when traveling on a flat surface. It is important that the floor surface is strongly pressed by the biasing force of the spring. When the driving wheel presses the floor surface with a strong force, the frictional force between the driving wheel and the floor surface is maintained, and the propulsive force for overcoming the step continues.
In general, a tension spring or a compression spring is used as a biasing member that biases the vertically displaceable driving wheel downward in the main body. The biasing force by which the driving wheel presses the floor surface is usually smaller as the driving wheel protrudes more greatly from the main body and is positioned below.
In order to achieve higher step-over performance, it is necessary to press the floor with a strong force even if the self-propelled electronic device reaches a high step and the drive wheel protrudes downward from the main body. The contradiction arises that the larger the protrusion, the smaller the biasing force of the spring described above.
The present invention has been made in consideration of the above-described circumstances, and when the drive wheel protrudes further downward from the main body when passing through the step, the pressing force with which the drive wheel presses the floor surface is reduced. It is preferable to provide a self-propelled electronic device having an urging mechanism that preferably increases the pressing force.

  The present invention includes a drive wheel, a drive unit that drives the drive wheel to self-run, and a suspension mechanism that supports the drive wheel so that the drive wheel can be displaced vertically with respect to a main body. An engagement portion that rotates around the shaft center according to the displacement of the drive wheel and engages the biasing member at a predetermined distance from the shaft center, and engages with the engagement portion and displaces the drive wheel toward the lower end. A biasing member that biases the drive wheel, and even if the biasing force of the biasing member gradually decreases as the drive wheel is displaced from the upper end to the lower end, The urging force is increased so that a component force of displacing the drive wheel to the lower end of the urging force is increased by gradually increasing an angle formed by the urging direction of the urging member within a range of 90 ° or less. Provided is a self-propelled electronic device in which a biasing force of a member and a position of the engaging portion are selected. That.

  In the self-propelled electronic device according to the present invention, the suspension mechanism includes the line extending from the engaging portion toward the shaft center and the urging force even when the urging force of the urging member gradually decreases as the driving wheel is displaced from the upper end to the lower end. When the angle formed by the biasing direction of the member gradually increases within a range of 90 ° or less, the component of the biasing member is strengthened so that the component of the biasing force to displace the drive wheel to the lower end is increased. Since the urging force and the position of the engaging portion are selected, the pressing force with which the driving wheel presses against the floor surface when the driving wheel protrudes further downward when passing through the step is preferably reduced. Can realize an urging mechanism in which the pressing force increases. As a result, a propulsive force that can overcome the step is obtained even when the driving wheel protrudes greatly below the main body when passing through the step, and a self-propelled electronic device having high step overstep performance can be realized. In addition, it is possible to realize a self-propelled electronic device that can travel stably without slipping the driving wheel even on an uneven floor surface.

It is an external appearance perspective view of the self-propelled cleaner which is one embodiment of this invention. It is a bottom view of the self-propelled cleaner shown in FIG. It is a vertical sectional view of the location including the drive wheel unit of the self-propelled cleaner shown in FIG. It is the 1st explanatory view showing signs that the drive wheel unit of the self-propelled electronic device shown in Drawing 3 is displaced in the up-and-down direction to the main part. (The drive wheel is at the upper end position with respect to the main unit) It is the 2nd explanatory view showing signs that the drive wheel unit of the self-propelled electronic equipment shown in Drawing 3 is displaced to the up-and-down direction to the main part. (The drive wheel is at the lower end position with respect to the main unit) It is the 1st explanatory view showing the case where the drive wheel unit shown in Drawing 4A is seen from the back side. (The drive wheel is at the upper end position with respect to the main unit) It is the 1st explanatory view showing the case where the drive wheel unit shown in Drawing 4B is seen from the back side. (The drive wheel is at the lower end position with respect to the main unit) It is explanatory drawing which looked at the drive wheel unit in this embodiment from the upper part. It is explanatory drawing which shows the internal structure of the drive wheel holder in this embodiment. In the upper end position of the drive wheels in this embodiment, the biasing member is an explanatory view showing a force F _l to rotate the drive wheel holder. (Position corresponding to FIG. 5A) In the lower end position of the drive wheels in this embodiment, the biasing member is an explanatory view showing a force F _l to rotate the drive wheel holder. (Position corresponding to FIG. 5B) It is a graph which shows the example of calculation of the magnitude | size of the torque T with respect to angle (theta) shown to FIG. 8A and FIG. 8B. It is the 1st explanatory view showing the mode which uses a compression spring as an energizing member in the drive wheel unit in this embodiment. (Embodiment 2) It is the 2nd explanatory view showing the mode which uses a compression spring as a biasing member in the drive wheel unit in this embodiment. (Embodiment 2) It is the 1st explanatory view showing the mode which uses a leaf spring as an energizing member in the drive wheel unit in this embodiment. (Embodiment 3) It is the 2nd explanatory view showing the mode which uses a leaf spring as an energizing member in the drive wheel unit in this embodiment. (Embodiment 3)

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In addition, the following description is an illustration in all the points, Comprising: It should not be interpreted as limiting this invention.

(Embodiment 1)
First, a self-propelled cleaner will be described as an example of the self-propelled electronic device of the present invention.
≪Configuration of self-propelled vacuum cleaner≫
As shown in FIG. 1, the self-propelled cleaner 10 of the present invention includes a substantially disc-shaped housing 102.
The housing 102 includes a bottom plate 102a (see FIG. 2), a top plate 102b, and a bottom plate 102a and an annular side plate 102c provided along the outer periphery of the top plate 102b. The side plate 102c is divided into two parts in the front-rear direction, the side plate front part functions as a bumper, and a collision sensor for detecting a collision of the side plate front part is provided inside. Further, as shown in FIG. 2, the front ultrasonic wave receiving unit 14F is disposed on the front side, the left ultrasonic wave receiving unit 14L is disposed on the left side, and the ultrasonic wave transmitting unit 14B is disposed therebetween. Although hidden in FIG. 1, the right ultrasonic wave receiver 14R is arranged on the right side, and the ultrasonic wave transmitter 14B is arranged between the right ultrasonic wave receiver 14R and the front ultrasonic wave receiver 14F.
The top plate 102b is provided with a lid that can be opened and closed in order to accommodate a container in a dust collection chamber not shown in FIG. An exhaust port 32 is formed in front of the lid portion of the top plate 102b. The part enclosed in the housing 102 is the apparatus main body.

Further, as shown in FIG. 2, the bottom plate 102a is formed with a plurality of left and right holes that expose the right driving wheel 18R and the left driving wheel 18L from the inside of the housing 102 and project outside. Behind these holes are a left drive wheel unit 23L and a right drive wheel unit 23R equipped with a drive mechanism for the left drive wheel 18L and the right drive wheel 18R.
Further, a rear wheel 18T, which is a driven wheel, is mounted on the bottom plate 102a. The direction of the rear wheel 18T can be freely changed on the floor surface. A left wheel floor sensor 16L is disposed in front of the left drive wheel 18L, and a right wheel floor sensor 16R is disposed in front of the right drive wheel 18R. A front floor sensor 16F is disposed at the front end, and a rear floor sensor 16T is disposed at the rear end.
In addition, an air inlet 31 is opened in the bottom plate 102a, and a rotating brush 36 that sweeps the floor surface is disposed in the opening. Further, side brushes 37 are arranged on the left and right sides of the intake port 31.

  The self-propelled cleaner 10 moves forward in a direction in which the right driving wheel 18R and the left driving wheel 18L rotate forward in the same direction, and the front ultrasonic receiving unit 14F is disposed (forward). Further, the left and right drive wheels rotate backward in the same direction and move backward, and turn by rotating in opposite directions. For example, the self-propelled cleaner 10 has left and right driving wheels when any of the front ultrasonic receiving unit 14F, the left ultrasonic receiving unit 14L, and the right ultrasonic receiving unit 14R detects an obstacle on the path. Stop after slowing down. Thereafter, the left and right drive wheels are rotated in opposite directions to turn and change directions. In this way, the self-propelled cleaner 10 self-propels on the floor while avoiding obstacles at the place where it is installed.

≪Drive wheel unit and its structure≫
Since the left driving wheel unit 23L and the right driving wheel unit 23R are symmetrically paired, they are collectively referred to as the driving wheel unit 23. In addition, if one mechanism is described, the other is bilaterally symmetrical and the same mechanism, and therefore the following description of the drive wheel unit 23 is represented by the left drive wheel unit, and the description of the right drive wheel unit is omitted. In the following description, the left and right distinction may be omitted for the names and symbols of the respective parts.

FIG. 3 is a vertical cross-sectional view along the front-rear direction of the portion including the left drive wheel unit 23L of the self-propelled cleaner 10 shown in FIG.
4A and 4B are explanatory views showing a state in which the drive wheel unit 23 in the self-propelled cleaner 10 of this embodiment is displaced in the vertical direction with respect to the housing 102. FIG. FIG. 5A and FIG. 5B are other explanatory views showing how the driving wheel unit 23 is displaced in the vertical direction with respect to the housing 102. Here, FIGS. 4A and 5A correspond to the position of the upper end where the drive wheel of the self-propelled cleaner 10 has moved most to the main body side, and FIGS. 4B and 5B show the self-propelled cleaner 10 passing through the steps. And so on, corresponding to the position of the lower end of the state where the drive wheel protrudes downward from the main body. 4B and 5B, the bottom plate 102a is used as a horizontal reference for easy comparison with FIGS. 4A and 5A. However, the state in which the front of the bottom plate 102a is lifted by reaching the level difference of the horizontal floor surface F. This is shown by drawing the floor surface F tilted.
FIG. 6 is an explanatory view of the left wheel drive motor 21L, the left drive wheel 18L, and the drive wheel holder 221 included in the left drive wheel unit 23L as viewed from above. FIG. 7 is an explanatory view showing the internal structure of the drive wheel holder 221.
4A to 7 show only the left drive wheel unit 23L, but the right drive wheel unit 23R has the same configuration although it is symmetrical with them.

The drive wheel unit 23 includes a left drive wheel 18L, a drive wheel holder 221 that holds the left drive wheel 18L so as to be rotatable about a first axis P ₁ in the left-right direction, and a left wheel drive motor attached to the drive wheel holder 221. 21L. Furthermore, it has a drive transmission mechanism 223 that transmits the driving force of the left wheel drive motor 21L to the left drive wheel 18L (see FIGS. 6 and 7).

The drive wheel holder 221 includes an inner case 221a and an outer case 221b. Inside the first gear 223a as a drive transmission mechanism 223, the second gear 223b _2, third gear 223b _3, it turned to the fourth gear 223c _2, fifth gear 223c ₃ and sixth gear housing chamber 221r for accommodating the gear 223d ₂ ing. The drive wheel holder 221 has a cylindrical portion 221a ₁ into which the left wheel drive motor 21L is fitted into the inner case 221a.

The cylindrical portion 221a ₁ is provided on one end (front end) side in the longitudinal direction of the inner case 221a, and the left wheel drive motor 21L is fitted and fixed at that position. In response to the center of the cylindrical portion 221a ₁ of the inner casing 221a, a cylindrical portion 221b ₁ is formed on the outer casing 221b. Further, an engaging portion 221a ₂ is formed on the outer peripheral surface of the cylindrical portion 221a ₁ , and one end of a tension spring as the biasing member 241 is hooked. The other end of the tension spring is hooked on the support member 231.

Tension spring when you Chijimimo by the elastic engaging portion 221a ₂ of the front end of the spring is hooked tension is rotated about the axis P _2. That is, the cylindrical portion 221a ₁ of the spring front end hooked, the engaging portion 221a ₂ around the axis P ₂ constitute a crank mechanism for turning. A cylindrical portion 221a ₁ integral with the drive wheel holder 221 and the left drive wheel 18L is displaced toward the lower end position.
The first axis P _{1 of} the sixth gear 223d ₂ and the second axis P _{2 of} the first gear 223a are parallel. That is, parallel to the drive shaft m ₁ of the axis and the left wheel drive motor 21L of the left driving wheel 18L, which is parallel to the axis and the cylindrical portion 221a ₁ of the pivot axis of the left drive wheel 18L.

Driving force of the drive shaft _{m 1} of the left wheel drive motor 21L is transmitted to the sixth gear 223d ₂ via the first gear 223a~ fifth gear 223c _3. The sixth gear 223d ₂ and the left drive wheel 18L are connected to rotate integrally. Thereby, the driving force of the left wheel driving motor 21L is transmitted to the left driving wheel 18L.

As shown in FIGS. 4A and 5A, the self-propelled cleaner 10 is supported on the floor F by the left and right drive wheels via the support member 231 and the drive wheel holder 221 coupled to the bottom plate 102a. In this case, since according to the weight drive wheel unit 23 of the housing 102, the cylindrical portion 221a ₁ and 221b ₁ is drive wheel holder 221 as pivot shaft pivots (displaced) about the second axis P ₂ Thus, most of the left drive wheel 18L is housed in the support member 231. At the same time, the front end of the urging member 241 moves in the direction pulled forward. By biasing member 241 extends pulled, the left driving wheel 18L which rotates about the axis P ₂ integrally with the drive wheel holder 221 is biased in a direction to press the floor F.

As shown in FIGS. 4B and 5B, when the bottom plate 102a is lifted from the floor surface F, the left drive wheel 18L protrudes downward from the main body, and the front end of the urging member 241 is pulled rearward. Further, the drive wheel unit 23 rotates about the second axis P ₂ around the cylindrical portions 221a ₁ and 221b ₁ as a rotation axis, and the left drive wheel 18L protrudes to the outside of the support member 231. .
4B and 5B show a state in which the left driving wheel 18L protrudes most downward in the main body, but the tension spring of the biasing member 241 is still extended beyond the natural length even at this lower end position, The wheel holder 221 and the left drive wheel 18L are biased. Since the left driving wheel 18L is pressed against the floor surface F by the urging force, the left driving wheel 18L follows the floor surface F firmly and grips it. That is, the self-propelled cleaner 10 has excellent step-over performance.

When the self-propelled cleaner 10 is placed on the horizontal floor F, the left drive wheel 18L moves slightly downward from the upper end position shown in FIG. 4A and FIG. The vacuum cleaner 10 stands still or runs in that state. That is, the left drive wheel 18L is in a displacement region between the upper end position shown in FIGS. 4A and 5A and the lower end position shown in FIGS. 4B and 5B, and moves up and down according to the unevenness and steps of the floor surface F. While driving.
As is apparent from FIGS. 5A and 5B, the urging member 241 has a height dimension (H1 shown in FIG. 5A and H2 shown in FIG. 5B) regardless of the position of the left drive wheel 18L from the upper end to the lower end. It is attached so as to be smaller than the horizontal dimension (W1 shown in FIG. 5A and W2 shown in FIG. 5B).
That is, in FIG. 5A showing the upper end position of the left drive wheel 18L, the relationship of H1 <W1 is established, and in FIG. 5B showing the lower end position of the left drive wheel 18L, the relationship of H2 <W2 is established. The same relationship holds at any position between them.

≪Drive wheel position and floor pressure≫
The biasing force applied to the drive wheel holder 221 by the biasing member 241 is calculated. The urging force acts so that the driving wheel (the left driving wheel 18L in FIGS. 5A and 5B) attached to the tip of the driving wheel holder 221 presses the floor surface F.
FIG. 8A and FIG. 8B are explanatory diagrams showing the force F ₁ (Fuel) that causes the urging member 241 to rotate the driving wheel holder 221 at the upper end and lower end positions of the left driving wheel 18L. The position of the drive wheel holder 221 shown in FIGS. 8A and 8B corresponds to FIGS. 5A and 5B, respectively.

In FIG. 8A and FIG. 8B, the length of the tension spring which is the urging member 241 is indicated by 1 (el). Further, a distance from the axis P ₂ to the front end of the biasing member 241, that is, a circle in which the engaging portion 221 a ₂ in which the front end of the biasing member 241 is hooked on the cylindrical portion 221 a ₁ rotates about the axis P _2. The radius of is denoted by r. That is, the radius r is a distance from the axis P ₂ to the engaging portion 221a ₂ . The distance from the axis P ₂ to the position where the rear end (spring rear end 241t) of the biasing member 241 is hooked on the support member 231 is indicated by x.

The front end (engaging portion 221a ₂ ), rear end (spring rear end 241t), and axis P ₂ of the biasing member 241 form a triangle. Among the triangles, the magnitude of the apex angle of the spring rear end 241t is indicated by ψ (psi). The angle of the sides extending extension of the sides extending in the axis P ₂ and the axis P ₂ from the spring rear end 241t to the engaging portion 221a ₂ shown in theta (theta). The magnitude of the angle θ is 180 °, that is, π radians minus the apex angle of the axis P ₂ .
Further, an angle formed between the tangent line orthogonal to the radius r and the urging member 241 is represented by φ (phi). The angle φ is a complementary angle with respect to the apex angle of the engaging portion 221a _{2 in} the above-described triangle.

8A and 8B, the biasing member 241 indicates a force for rotating the drive wheel holder 221 about the axis P ₂ at an engagement portion 221a ₂ at _{F l.} Orientation of the F _l is the direction along the circumference of a circle of radius r centered at the axis P _2, a direction in which the biasing member 241 is going Chijimimo.

The biasing member 241 is a torque T to rotate the drive wheel holder 221 about the axis P ₂ is expressed by the following equation.
T = F _l × r (1)

If the natural length of the tension spring is a biasing member 241 L, the spring constant is K, F _l is expressed by the following equation.
F _l = K × (l−L) × cos φ (2)
Here, (1-L) is the extension of the spring.
F ₁ is expressed as a component in the tangential direction of a circle whose center is P _{2 and} whose radius is r, out of the force that the tension spring tries to contract. As the left drive wheel 18L moves up and down, both the spring length l (el) and the angle φ change, and the magnitude of _Fl changes.

Consider representing the angle φ by the angle θ. The front end of the biasing member 241, focusing on a triangle whose vertices rear end and axis P _2, since the sum of interior angles of a triangle is π radians,
ψ + (π−θ) + (π / 2−φ) = π
The relationship is established. Transform this,
ψ−θ−φ = −π / 2
φ = π / 2 + ψ−θ (3)
Expression (3) is a relational expression in which the angle φ is represented by angles ψ and θ.

From FIG. 8A and FIG. 8B,
l × cos ψ = x + r × cos θ
Using this relationship,
tan ψ = (r × sin θ) / (x + r × cos θ) (4)
It can be expressed as.
Expression (4) is a relational expression that represents the angle ψ by the angle θ.

By applying the equation (4) to the equation (3), the angle φ can be expressed by the angle θ without using the angle ψ.
By applying the result to equation (2), it can represent F _l of the formula (2) at an angle theta, can thus represent the torque T of the formula (1) at an angle theta.
The force with which the left drive wheel 18L presses the floor surface F is substantially proportional to the torque T.

Strictly speaking, changes in the angle at which the line connecting the axial center P ₁ and P ₂ forms with the bottom plate 102a, the angle of inclination of the floor surface F to the base plate 102a should also be considered. However, since these conditions vary depending on the shape of the step, it is difficult to determine in advance. Therefore, it is meaningful to consider that the pressing force of the drive wheel against the floor surface F is substantially proportional to the magnitude of the torque T and to use it as a design guide.

FIG. 9 is a graph showing a calculation example of the magnitude of the torque T with respect to the angle θ using the above equations (1) to (4). In FIG. 9, the horizontal axis is the angle θ and is calculated in the range of about 0 ° to 180 °. The vertical axis indicates the magnitude of the torque T. The numerical values and units used in the calculation are as follows.
r = 30 (mm)
x = 100 (mm)
L = 60 (mm)
K = 50 (N / m)
As can be seen from FIGS. 8A and 8B, the total length of the tension spring is longer than x at any position between the upper end and the lower end of the left drive wheel 18L. The x is a length that is at least three times the radius r. Therefore, at any position from the upper end to the lower end of the driving wheel, the total length of the tension spring is at least three times the radius.

As shown in FIG. 9, when the angle θ approaches 0 ° and 180 °, the torque T converges to zero. Referring to FIGS. 8A and 8B, the position where the angle θ is zero corresponds to the top dead center where the biasing member 241 is fully extended. On the other hand, the position where the angle θ is 180 ° corresponds to the bottom dead center where the urging member 241 contracts most. In either case, the line or extension thereof on connecting the front and rear ends of the biasing member 241 has axial P ₂ position, the torque to rotate the cylindrical portion 221a ₁ does not occur at that position .

Further, in a region where the angle θ is greater than 0 ° and less than 180 °, a torque is generated to rotate the cylindrical portion 221a ₁ . In the example shown in FIG. 9, the torque T increases monotonously as the angle θ increases in the vicinity of 0 °, but reaches a peak when the angle θ reaches 75 ° (critical point indicated by C in FIG. 9). After passing the critical point C, the torque T decreases monotonically until the angle θ reaches 180 °. In FIG. 9, a region where the angle θ is monotonically increasing from 0 ° to the critical point C is denoted by Ri, and a region where the angle θ is monotonously decreasing from the critical point C to 180 ° is denoted by Rd.

In this embodiment, the urging member 241 is attached so that the displacement region extending from the upper end position to the lower end position of the left drive wheel 18L is covered by the monotonically increasing region Ri shown in FIG. Energize.
In the region Ri, the angle θ to project left drive wheel 18L is the more lower body is increased, the force for pressing by rotating the drive wheel holder 221 about the axis P ₂ of the left driving wheel 18L to the floor F is increased To do. Therefore, even if the left drive wheel 18L protrudes greatly downward from the main body when passing through the step, a propulsive force that firmly grips the floor F and gets over the step can be obtained. In addition, the driving wheel can stably travel without slipping even on an uneven floor surface.

As described above, the tension spring itself as the biasing member 241 is longer when the left drive wheel 18L is at the upper end position (corresponding to FIG. 8B) than when the left drive wheel 18L is at the lower end position (corresponding to FIG. 8A). Since it is extended, a large urging force is generated in the direction in which the spring contracts. That is, when the urging force that the tension spring tries to contract against the angle θ is plotted, a monotonically decreasing curve is obtained.
However, the front end of the tension spring constitutes a crank mechanism mounted around the axis P ₂ with the engaging portion 221a ₂ of the rotatable cylindrical portion 221a _1. Left drive wheel 18L and the driven wheel holder 221 is rotated to the axis P ₂ about its crank integral. Torque T for rotating the crank by the urging force of the urging member 241 is proportional to the component force F _l in the circumferential direction of the crank of the biasing force of the tension spring. Therefore, when the torque T is plotted against the angle θ, a curve that shifts from a monotonic increase to a monotonic decrease through the critical point C as shown in FIG.

(Embodiment 2)
In the first embodiment, the case where the urging member 241 is a tension spring has been described, but the urging member 241 is not limited to the tension spring.
In this embodiment, a configuration example using a compression spring as the biasing member 241 is shown.
10A and 10B are explanatory views showing a mode in which a compression spring is used as an urging member in the drive wheel unit in this embodiment.

The positions of the left driving wheel 18L and the driving wheel holder 221 in FIGS. 10A and 10B correspond to FIGS. 5A and 5B, respectively.
The position of the engaging portion 221a ₂ of the cylindrical portion 221a ₁ may be a point-symmetrical position with respect to the engaging portion 221a ₂ and the axis P ₂ shown in FIGS. 5A and 5B using a tension spring. If the amount of displacement from the natural length of the spring and the spring coefficient are equal to the tension spring shown in FIGS. 5A and 5B, a torque T equivalent to that shown in FIG. 9 can be obtained.

(Embodiment 3)
In this embodiment, a mode in which a leaf spring is used as the biasing member 241 will be described.
FIG. 11A and FIG. 11B are explanatory views showing a mode in which a leaf spring is used as an urging member in the drive wheel unit in this embodiment.
The positions of the left drive wheel 18L and the drive wheel holder 221 in FIGS. 11A and 11B correspond to FIGS. 5A and 5B, respectively.

As shown in FIGS. 11A and 11B, the cylindrical portion 221a ₁ is formed with an engaging portion 221a ₂ that engages with a leaf spring as the biasing member 241 at one location near the periphery. Engaging portion 221a ₂ is a member of the parallel rod-shaped axis P _2, may be fitted is rotatable ring around in order to reduce the friction of the portion in contact with the leaf spring.
The upper end of the leaf spring is slightly than immediately above the axis P ₂ is fixed to the supporting member 231 at a leftward position, the lower end is below and right side position than the engaging portion 221a _2. The leaf spring urges the engaging portion 221a ₂ to the left, and a torque T for causing the left driving wheel 18L and the driving wheel holder 221 to protrude from the main body is obtained by the urging force.
As shown in FIGS. 11A and 11B, the deformation of the leaf spring increases as the engaging portion 221a ₂ moves toward the right side, and the force for urging the engaging portion 221a ₂ to the left increases. In FIGS. 5A and 5B, is the same as the engaging portion 221a ₂ large urging force elongation as tension spring stop by the front is obtained.

As mentioned above,
(I) A self-propelled electronic device according to the present invention includes a drive wheel, a drive unit that drives and drives the drive wheel, and a suspension mechanism that supports the drive wheel so that the drive wheel can be displaced vertically with respect to a main body. The suspension mechanism rotates around an axis according to displacement of the drive wheel and engages with a biasing member at a predetermined distance from the axis, and engages with the engagement part And an urging member that urges the drive wheel to be displaced toward the lower end, and the engagement even if the urging force of the urging member gradually decreases as the drive wheel is displaced from the upper end to the lower end. As the angle formed by the line from the portion toward the shaft center and the urging direction of the urging member gradually increases within a range of 90 ° or less, the driving wheel of the urging force is displaced toward the lower end. The biasing force of the biasing member and the position of the engaging portion are selected so that the force is strong And wherein the Rukoto.

  In this invention, a drive part drives a driving wheel and makes an apparatus self-propelled. For example, a motor for rotating the drive wheel, a drive mechanism for transmitting the power of the motor to the drive wheel, and a method for controlling traveling by rotating and stopping the drive wheel according to the surrounding situation. A control circuit or the like corresponds to the drive unit.

The engaging portion engages with the urging member and converts the urging force of the urging member into a force that displaces the drive wheel toward the lower end. That is, it is an element constituting a crank mechanism that attempts to rotate around the axis by the urging force from the urging member. In the above-described embodiment, the engaging portion 221a ₂ formed on the outer peripheral portion of the cylindrical member 221a ₁ corresponds to that.

The angle formed by the line extending from the engaging portion toward the shaft center and the urging direction of the urging member is determined by fitting the shaft P ₂ , the engaging portion 221a ₂ and the spring rear end 241t with reference to FIGS. 8A and 8B. This corresponds to the apex angle of the engaging portion 221a ₂ among the triangles having three vertices. The additional angle of the apex angle of the engaging portion 221a ₂ is the angle φ. Therefore, when the angle formed by the line from the engaging portion toward the shaft center and the urging direction of the urging member is gradually increased within a range of 90 ° or less, the angle φ, which is a residual angle, gradually decreases, and the urging direction is gradually to match the tangent of a circle around the axis P _2.

  Furthermore, the description that the urging force of the urging member and the position of the engaging portion are selected so that the component force for displacing the drive wheel to the lower end of the urging force is increased is described in the above embodiment. This corresponds to the following configuration. That is, the region indicated by Ri in FIG. 9 includes a displacement region in which the driving wheel is displaced from the upper end to the lower end. In the region Ri, the torque T increases monotonously as the angle θ increases.

Furthermore, the preferable aspect of this invention is demonstrated.
(Ii) The urging member may be attached such that the height of the driving wheel is smaller than the size of the lateral direction at any position from the upper end to the lower end of the driving wheel.
In this way, a thin self-propelled electronic device can be realized by disposing the urging member in a horizontally long manner and mounting it even if the suspension mechanism is provided. For example, a self-propelled vacuum cleaner that is one aspect of the self-propelled electronic device is preferably a thin one having a small height dimension so that a low gap under a sofa or a bed can be cleaned. The mechanism is preferred.

(Iii) The biasing member may be a tension spring, and the total length of the tension spring may be three times or more the predetermined distance at any position from the upper end to the lower end of the driving wheel.
In this way, a thin self-propelled electronic device can be realized by arranging it horizontally, even if it is a tension spring that is three times or more the distance from the shaft center to the engaging portion.

(Iv) The biasing member may be a compression spring or a leaf spring.
If it does in this way, not only a tension spring but other things can be applied as a biasing member.

(V) The direction of the axis may be parallel to the rotation axis of the drive wheel.
In this way, when the drive wheel is displaced up and down, the engaging portion rotates around an axis parallel to the rotation axis of the drive wheel, so that a suspension mechanism with a simple configuration can be realized.
Preferred embodiments of the present invention include combinations of any of the plurality of embodiments described above.
In addition to the embodiments described above, there can be various modifications of the present invention. These modifications should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the scope of the claims and all modifications within the scope.

10: Self-propelled cleaner, 14B: Ultrasonic transmitter, 14L: Left ultrasonic receiver, 14F: Front ultrasonic receiver, 14R: Right ultrasonic receiver, 16L: Left wheel floor sensor, 16R: Right wheel floor sensor, 16F: Front floor sensor, 16T: Rear floor sensor, 18R: Right drive wheel, 18L: Left drive wheel, 18T: Rear wheel, 21L: Left wheel drive motor, 23: Drive wheel unit, 23L : Left drive wheel unit, 23R: Right drive wheel unit, 31: Intake port, 32: Exhaust port, 36: Rotating brush, 37: Side brush 102: Housing, 102a: Bottom plate, 102b: Top plate, 102c: Side plate 221 : Driving wheel holder, 221a: inner case, 221b: outer case, 221a ₁ , 221b ₁ : cylindrical portion, engaging portion: 221a ₂ , 221r: gear storage chamber, 223: drive transmission Reach mechanism, 223a: first gear, 223b _2: second gear, 223b _3: third gear, 223c _2: 4th gear, 223c _3: 5 gear, 223d _2: sixth gear, 231: supporting member, 241 : Urging member, 241t: spring rear end F: floor surface, m ₁ : drive shaft, P ₁ , P ₂ : shaft center

Claims (5)

Drive wheels,
A drive unit for driving the drive wheel to be self-propelled;
A suspension mechanism that supports the drive wheel so that it can be displaced vertically with respect to the main body,
The suspension mechanism rotates around an axis according to the displacement of the drive wheel and engages with a biasing member at a predetermined distance from the axis, and engages with the engagement part and moves to the lower end. An urging member that urges the drive wheel to be displaced toward the
Even if the urging force of the urging member gradually decreases as the driving wheel is displaced from the upper end to the lower end, the angle formed by the line from the engaging portion toward the shaft center and the urging direction of the urging member is 90. The urging force of the urging member and the position of the engaging portion are increased so that a component force to displace the drive wheel to the lower end of the urging force is increased by gradually increasing in a range of less than or equal to °. Selected self-propelled electronic device.   2. The self-propelled electronic device according to claim 1, wherein the urging member is attached such that a driving wheel has a height dimension smaller than a horizontal dimension at any position from an upper end to a lower end.   The self-propelled according to claim 2, wherein the urging member is a tension spring, and the total length of the tension spring is three times or more the predetermined distance at any position from the upper end to the lower end of the driving wheel. Electronic equipment.   The self-propelled electronic device according to claim 1, wherein the biasing member is a compression spring or a leaf spring.   The self-propelled electronic device according to any one of claims 1 to 4, wherein a direction of the axis is parallel to a rotation axis of the drive wheel.