Rotary electric shaver

Abstract

The invention provides a rotary electric shaver with a simple structure capable of suppressing damage to skin and improving sharpness. This rotary electric shaver is provided with an outer blade in which a hair inlet is formed, and an inner blade which rotates while being in sliding contact with the inner surface of the outer blade, the inner blade having a first small blade rising from a base surface and a second small blade rising from the base surface, a first tip blade tip is formed at the tip portion in the direction of rotation of the first small blade toward the upper end portion, a second tip blade tip is formed at the tip portion in the direction of rotation of the second small blade toward the upper end portion, the angle of the rake angle of the first tip blade tip is formed to be a relatively small angle, and the angle of the rake angle of the second tip blade tip is formed to be a relatively large angle.

Description

Technical Field

[0001] This invention relates to a rotary electric shaver. Background Technology

[0002] For example, a rotary electric shaver is known to have an outer blade with multiple hair inlets and an inner blade that rotates while sliding in contact with the inner surface of the outer blade, cutting the hair that enters the hair inlets (see Patent Document 1: Japanese Patent Application Publication No. 2007-135991).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-135991

[0006] Patent Document 2: Japanese Patent Application Publication No. 2015-223315 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] Regarding the conventional rotary electric shaver illustrated in Patent Document 1, while it optimizes shaving sharpness, there are precedents where the inner blades can cause skin damage and stinging. Therefore, the inventors developed a rotary electric shaver that includes an inner blade capable of rotating in both forward and reverse directions, and features both a sharpness mode and a mode that reduces skin damage and stinging (see Patent Document 2: Japanese Patent Application Publication No. 2015-223315).

[0009] However, the conventional rotary electric razor illustrated in Patent Document 2 has the problem that the mechanism is complicated in order to make the inner blade rotate in both the forward and reverse directions.

[0010] Solution for solving the problem

[0011] The present invention was made in view of the above circumstances, and its object is to provide a simple rotary electric razor with a structure that can suppress damage to the skin and improve sharpness.

[0012] One technical solution is a rotary electric shaver with a blade unit. This blade unit has an outer blade with multiple hair inlets and an inner blade that rotates while sliding in contact with the inner surface of the outer blade. The rotary electric shaver requires the following: the inner blade has multiple first small blades and multiple second small blades erected from the base surface; each first small blade has a first tip at its front end, facing the direction of rotation towards its upper end, capable of cutting hair entering the hair inlets; each second small blade has a second tip at its front end, facing the direction of rotation towards its upper end, capable of cutting hair entering the hair inlets; the rake angle α1 of the first tip is a relatively small angle, and the rake angle α2 of the second tip is a relatively large angle.

[0013] Thus, by using the first small blade, a blade tip that prioritizes sharpness (first front blade tip) can be achieved, and by using the second small blade, a blade tip that prioritizes damage suppression and whose sharpness is not significantly inferior to that of the first front blade tip (second front blade tip) can be achieved.

[0014] Preferably, the first small blade is disposed on the outer peripheral side of the base surface, the second small blade is disposed on the inner peripheral side of the base surface, the outer blade has a first outer blade disposed at a position corresponding to the first small blade, and a second outer blade disposed at a position corresponding to the second small blade, and the upper surface of the first outer blade is formed at a relatively high position, and the upper surface of the second outer blade is formed at a relatively low position.

[0015] Additionally, preferably, the angle α1 is formed as 30°≤α1≤90°, and the angle α2 is formed as 70°≤α2≤90°.

[0016] In addition, preferably, in the outer blades, the circumferential width of the hair inlet of the first outer blade is relatively narrow, and the circumferential width of the hair inlet of the second outer blade is relatively wide.

[0017] Furthermore, it is preferable that the outer blade has an outer blade cover embedded in the radial center position, and the upper surface of the outer blade cover is formed at a position lower than the upper surface of the second outer blade, such that when the height difference between the upper surface of the first outer blade and the upper surface of the second outer blade is set as D1, and the height difference between the upper surface of the second outer blade and the upper surface of the outer blade cover is set as D2, D2 ≤ D1 × 3.

[0018] Additionally, preferably, the outer blade has an outer blade cover embedded in a radially central position, and the upper surface of the outer blade cover is formed at a position lower than the upper surface of the first outer blade and higher than the upper surface of the second outer blade.

[0019] Additionally, preferably, the first blade is a structure in which it stands upright at an acute angle to the base surface in the direction of rotation, and the second blade is a structure in which it stands upright at an acute angle to the base surface in the direction opposite to the direction of rotation.

[0020] Additionally, preferably, the first and second blades are formed in a shape that is symmetrical about the front and back along the direction of rotation.

[0021] The effects of the invention

[0022] According to the present invention, a rotary electric razor can be realized, which has a simple structure in which the inner blade rotates only in one direction, thereby achieving damage suppression and improving sharpness. Attached Figure Description

[0023] Figure 1 This is a perspective view showing an example of a rotary electric razor according to an embodiment of the present invention.

[0024] Figure 2 It means Figure 1 An exploded perspective view of an example of the head of a rotary electric shaver.

[0025] Figure 3 It means Figure 1 A perspective view of an example of the inner blade of a rotary electric razor.

[0026] Figure 4A It means Figure 3 A side view of an example of the first small blade of the inner blade. Figure 4B yes Figure 4A An enlarged view of the upper part of the first small blade.

[0027] Figure 5A It means Figure 3 A side view of an example of the second small blade of the inner blade. Figure 5B yes Figure 5A An enlarged view of the upper part of the second small blade.

[0028] Figure 6 It means Figure 1 A perspective view of an example of the outer blade of a rotary electric razor.

[0029] Figure 7 It means Figure 6 A top view of an example of an outer blade shown.

[0030] Figure 8 yes Figure 7 Enlarged view of section VIII.

[0031] Figure 9 yes Figure 7 Sectional view along line IX-IX.

[0032] Figure 10 It means Figure 1 A perspective view of an example of the outer blade cover of a rotary electric razor. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a perspective view (schematic view) showing an example of the rotary electric shaver 1 according to this embodiment. Additionally, Figure 2 This is an exploded perspective view (schematic view) showing an example of the head 3 of a rotary electric shaver 1. Furthermore, in all the drawings used to illustrate the embodiments, components having the same function are labeled with the same reference numerals, and repeated descriptions are omitted.

[0034] like Figure 1 , Figure 2 As shown, the rotary electric shaver 1 of this embodiment is a rotary electric shaver that has an outer blade 22 and an inner blade 42. A plurality of hair inlets 22c are formed through the outer blade 22. The inner blade 42 rotates while sliding in contact with the inner surface 22b of the outer blade 22, and the outer blade 22 and inner blade 42 are used to trim the hair X entering the hair inlets 22c. Furthermore, the following example will be given for illustration: a rotary electric shaver having three sets of blade units 6 composed of outer blades 22 and inner blades 42, but it is not limited to this.

[0035] exist Figure 1 In the figure, reference numeral 2 indicates the main body, which has a generally cylindrical housing 10. A switch 16 for turning the power on and off and switching the usage mode is provided on the front surface of the housing 10.

[0036] On the other hand, the housing 10 contains a motor that drives the inner blade 42 to rotate, a battery that supplies power to the motor, and a control unit that controls the rotation of the motor (all not shown).

[0037] like Figure 2As shown, the head 3 includes: a head housing 32, which is connected to the upper part of the housing 10 of the main body 2; a blade holder 30, which covers the head housing 32 from above; a drive mechanism (not shown), which is housed in the inner bottom of the head housing 32; and three sets of blade units 6, which are held in the blade holder 30 in a manner that allows them to move slightly up and down and to swing. Here, each blade unit 6 has a generally disc-shaped outer blade 22 and an inner blade 42 that rotates while sliding in contact with the inner surface 22b of the outer blade 22. In addition, the three sets of blade units 6 are arranged in a triangular shape when viewed from above. Furthermore, as described above, this embodiment is an example of having three sets of blade units 6, but the basic structure can also be considered the same when there are other than three sets of blade units.

[0038] Here, the outer blade 22 is structured such that multiple hair inlets 22c (such as slits, holes, etc., but not limited to) are formed through it along the axial direction (that is, in the same direction as the rotation axis of the inner blade 42), and the inner blade 42 trims the hair X that enters the hair inlets 22c. That is, the outer blade 22 is structured such that the upper surface (outer surface) 22a serves as the shaving surface in contact with the user's skin, and the hair inlets 22c open on the upper surface 22a. For example, the upper surface 22a is formed as a ring-shaped plane. Furthermore, the outer blade 22 has a shape with its periphery bent downwards, and an outer blade ring 24 is fitted around its periphery. In addition, a stop ring 26 is embedded in the inner circumference of the outer blade ring 24 to fix the outer blade 22 to the outer blade ring 24.

[0039] On the other hand, the inner blade 42 is fixed to the inner blade holder 44, and a recess is formed in the lower part of the inner blade holder 44 for fitting the upper end of the inner blade drive shaft (not shown) connected to the output shaft of the motor. The inner blade 42 is held on the side of the outer blade 22 in a swingable manner by the inner blade support 46 embedded in the outer blade ring 24, thereby forming three independent blade units 6.

[0040] By assembling the blade unit 6 with the above structure, the inner blade 42 (the small blade 42A described later) comes into contact with the outer blade 22 (the inner surface 22b described later). In this state, by driving the inner blade 42 to rotate, the tip of the inner blade 42 (the small blade 42A) can be used to trim the hair X that has entered the hair inlet 22c.

[0041] Switch 16 is an operating switch used to switch the power supply on and off. As an example, a push-button switch can be used, for instance, it can be configured such that when switch 16 is pressed once, the power is turned on and the motor is driven, and when it is pressed again (a total of two times), the power is turned off and the motor stops. However, it is not limited to this structure and can also be configured to include a mode that switches the motor speed between high and low speeds. Alternatively, a slide switch (not shown) can be used instead of a push-button switch.

[0042] Next, use Figures 3 to 5B The structure of the inner blade 42 is described in detail. Figure 3 This is a perspective view of the inner blade 42 (upper surface side). Additionally, Figure 4A This is a side view of the first small blade 42A (described later) of the inner blade 42. Figure 4B This is an enlarged view of the upper part of the first small blade 42A. Additionally, Figure 5A This is a side view of the second small blade 42B (described later) of the inner blade 42. Figure 5B This is an enlarged view of the upper part of the second small blade 42B. Furthermore, in each figure, the rotation direction of the inner blade 42 is indicated by the direction of arrow F. Also, for the sake of simplicity, only a portion of the small blades 42A and 42B are labeled with reference numerals.

[0043] As an example, the inner blade 42 is formed as a single piece using a flat metal material made of stainless steel alloy, through a stamping process involving demolding and bending. This allows for a reduction in component and assembly costs by forming the inner blade 42 with a simpler structure and fewer steps. However, it is not limited to a single-piece construction.

[0044] The inner blade 42 of this embodiment includes a plurality of small blades that cause a portion of the metal plate 42C to stand upright relative to the base surface (upper surface) 42Ca. Specifically, it has a so-called double-track structure: on the base surface (upper surface) 42Ca, a plurality of first small blades 42A are provided on the outer circumference, and a plurality of second small blades 42B are provided on the inner circumference. However, it is not limited to this and may also be configured as a three-track structure with three rows of small blades or other structures (not shown).

[0045] Here, the first blade 42A has a structure that stands upright at an acute angle (angle β1 of the standing angle) from the base surface 42Ca toward the rotation direction F. On the other hand, the second blade 42B has a structure that stands upright at an acute angle (angle β2 of the standing angle) from the base surface 42Ca toward a direction opposite to the rotation direction F.

[0046] As an example, the first blade 42A and the second blade 42B are approximately prismatic in shape with a rectangular cross-section of about 1 mm on one side (radial side) and about 0.5 mm on the other side (circumferential side), and their lengths L1 and L2 are about 3 mm. However, they are not limited to this size and shape. Furthermore, further shortening the lengths L1 and L2 can increase the rigidity of the blade 42A, preventing bending and vibration during operation, thus improving sharpness.

[0047] The first blade 42A, rotating in the direction F toward its upper end 42Aa, has a first tip 42Ax ​​formed at its front end 42Ab, capable of cutting hair X entering the hair inlet 22c. Similarly, the second blade 42B, rotating in the direction F toward its upper end 42Ba, has a second tip 42Bx formed at its front end 42Bb, capable of cutting hair X entering the hair inlet 22c. In this embodiment, the rake angle α1 of the first tip 42Ax ​​is relatively small (i.e., relatively sharp), while the rake angle α2 of the second tip 42Bx is relatively large (i.e., relatively unsharp).

[0048] Based on the above structure, a blade tip (first tip tip 42Ax) that prioritizes sharpness can be achieved using the first small blade 42A. Furthermore, a blade tip (second tip tip 42Bx) that prioritizes damage suppression and whose sharpness is not significantly inferior to the first tip tip 42Ax ​​can be achieved using the second small blade 42B. Therefore, an electric razor 1 can be provided such that even with a structure where the inner blade 42 rotates only in one direction (direction F) (i.e., a structure without a reversing function), damage suppression and improved sharpness can be achieved.

[0049] In addition, as an additional function, if the structure is designed to set the rotation speed of the inner blade 42 to multiple stages, then a more suitable shaving method can be selected based on the user's preferences, hair condition (length, amount, etc.), and skin condition (damage, sensitivity, etc.).

[0050] Regarding the specific angle settings of the inner blades 42 (first small blade 42A and second small blade 42B), the inventors conducted in-depth research and confirmed that if inner blades 42 with angle α1 set to 30°≤α1≤90° and angle α2 set to 70°≤α2≤90° are used, the balance between improved sharpness and damage suppression is improved. Furthermore, regarding angles β1 and β2, they can be appropriately set within the range of 45° to 90°.

[0051] Furthermore, the inner blade 42 can be configured such that the first small blade 42A and the second small blade 42B are symmetrical about each other along the rotation direction F. Specifically, in the first small blade 42A, a first rear end tip 42Ay, symmetrical to the second front tip 42Bx of the second small blade 42B and having the same shape, can be provided at the rear end 42Ac in the rotation direction F toward the upper end 42Aa. Furthermore, in the second small blade 42B, a second rear end tip 42By, symmetrical to the first front tip 42Ax ​​of the first small blade 42A and having the same shape, can be provided at the rear end 42Bc in the rotation direction F toward the upper end 42Ba.

[0052] According to this structure, both the first blade 42A and the second blade 42B are designed to face the rotation direction F and form a blade tip at the rear end. Therefore, by adding a function to reverse the inner blade 42, it is possible to further increase the balance between sharpness enhancement and damage suppression, providing a variety of shaving methods suitable for the user.

[0053] The structure of the inner blade 42 in a representative embodiment has been described above, but it is not limited to this structure; other structures may also be used. Specifically, the first blade 42A and the second blade 42B, which are arranged in an inner and outer ring, may be positioned so that they stand together at an acute angle to the direction of rotation, or they may stand together at an acute angle to the direction opposite to the direction of rotation (neither shown). Furthermore, in these structures, by adjusting their respective lengths L1 and L2 (for example, in the case where the first blade 42A and the second blade 42B stand together at an acute angle to the direction of rotation, L1>L2), it is possible to achieve the aforementioned front angle relationship, i.e., α1<α2. Therefore, damage suppression and improved sharpness can be achieved.

[0054] Next, use Figures 6-10 The structure of the outer blade 22 is described in detail. Figure 6 This is a perspective view of the outer blade 22 (upper surface side). Figure 7 This is a top view of the outer blade 22. Additionally, Figure 8 yes Figure 7 An enlarged view of section VIII. Additionally... Figure 9 yes Figure 7 Sectional view along line IX-IX. Figure 10 This is a perspective view (lower surface side) of the outer blade cover 28. Furthermore, for the sake of simplicity, only a portion of the hair inlet 22c is marked with reference numerals.

[0055] As an example, the outer blade 22 is formed as a single piece using a flat metal material made of stainless steel alloy and through processes such as stamping, demolding, drawing, and bending, resulting in a roughly cup-shaped form with its periphery bent downwards. Furthermore, in this embodiment, an outer blade cover 28 made of resin material is fixed (embedded) in a through hole 22D, which is formed at the radial center of the outer blade 22.

[0056] On the other hand, such as Figure 10 As shown, the outer blade cover 28 is formed in a generally cup-shaped manner using resin material, and has a cylindrical portion 28a at the bottom. This cylindrical portion 28a engages with a protruding portion 44a located at the radial center of the inner blade 42. Furthermore, a plurality of protrusions 28b are provided on the outer wall of the cylindrical portion 28a, and these protrusions 28b are riveted and fixed to the through hole 22D of the outer blade 22. Thus, the outer blade 22 and the outer blade cover 28 (in this case, the cylindrical portion 28a) are fitted together with their centers aligned. Additionally, a decorative plate 29 made of a metal material such as stainless steel alloy is fitted onto the upper part of the outer blade cover 28, but the structure may omit this decorative plate 29.

[0057] As described above, this embodiment has a so-called dual-track structure, with the outer blade 22 having a double-ringed structure when viewed from above, corresponding to the structure of the inner blade 42. That is, the outer blade 22 is configured to include: a first outer blade 22A, which is located at a position corresponding to the first small blade 42A and in sliding contact with it; a second outer blade 22B, which is located at a position corresponding to the second small blade 42B and in sliding contact with it; and an annular groove 22C, which is located between the first outer blade 22A and the second outer blade 22B (at the radially intermediate position).

[0058] Both the first outer blade 22A and the second outer blade 22B have multiple hair inlets 22c. As an example, the first outer blade 22A has a structure in which slit-shaped (elongated) hair inlets 22c1 with relatively long radial lengths and slit-shaped (elongated) hair inlets 22c2 with relatively short radial lengths are alternately arranged in the circumferential direction. On the other hand, the second outer blade 22B has a structure in which a set of slit-shaped (elongated) hair inlets 22c3 and a set of round-hole-shaped hair inlets 22c4 are alternately arranged in the circumferential direction. However, these structures are not limited to, and various settings can be made for shapes, arrangements, etc.

[0059] like Figure 8As shown, in this embodiment, the outer blade 22 is configured such that the circumferential width W1 (referring to the maximum width, here the width at the radial center position) of the elongated hair inlet 22c1 of the first outer blade 22A is relatively narrow, while the circumferential width W2 (referring to the maximum width, here the width at the radial center position) of the elongated hair inlet 22c3 of the second outer blade 22B is relatively wide. According to this structure, deep shaving can be performed particularly using the inner circumferential side, i.e., the second outer blade 22B and the second small blade 42B, and damage suppression can also be achieved using the shape of the second tip 42Bx in the second small blade 42B. Furthermore, in this embodiment, the circumferential widths of the hair inlet 22c1 and the hair inlet 22c2 are the same.

[0060] In addition, such as Figure 9 As shown, in this embodiment, the outer blade 22 is formed such that the upper surface 22a1 of the first outer blade 22A is at a relatively high position, and the upper surface 22a2 of the second outer blade 22B is at a relatively low position (in...). Figure 9 In this context, the difference in height dimension is denoted as D1. According to this structure, deep shaving can be performed using the inner circumferential side, i.e., the second outer blade 22B and the second small blade 42B, and damage suppression can also be achieved using the shape of the second tip 42Bx in the second small blade 42B. Furthermore, as a variation, the upper surface 22a1 and the upper surface 22a2 can be configured to have the same height.

[0061] Furthermore, in this embodiment, the upper surface 28c of the outer blade cover 28 (including the decorative panel 29) is (in Figure 9 (Indicated by dashed lines) is formed at a position lower than the upper surface 22a2 of the second outer blade 22B (in Figure 9 In this embodiment, the difference in height dimension is denoted as D2. According to this structure, the outer blade cover 28 can be used to suppress skin entrapment, thereby achieving damage suppression. In particular, the degree of damage suppression can be adjusted by setting the position of the upper surface 28c. For example, as in this embodiment, by setting the upper surface 28c to a position lower than the upper surface 22a2 of the second outer blade 22B, a high level of balance can be achieved between increased sharpness and damage suppression.

[0062] In the inventors' research, it was first confirmed that when the structure with the outer blade cover 28 is adopted, damage to the skin can be suppressed and reduced. The reason for this is believed to be that the outer blade cover 28 can mitigate the contact between the outer blade 22 and the skin. However, it was confirmed that when the upper surface 28c of the outer blade cover 28 (including the decorative plate 29) is positioned too high, for example, when the upper surface 28c is set higher than the upper surface 22a1 of the first outer blade 22A, shaving itself cannot be performed sufficiently. Based on this understanding, a structure in which the upper surface 28c of the outer blade cover 28 is positioned lower than the upper surface 22a1 of the first outer blade 22A is preferred. On the other hand, it was confirmed that when the upper surface 28c of the outer blade cover 28 is set too low compared to the upper surface 22a2 of the second outer blade 22B, the aforementioned skin-contact mitigation effect based on the outer blade cover 28 cannot be sufficiently obtained, and damage to the skin cannot be suppressed or reduced. Therefore, in order to avoid the upper surface 28c of the outer blade cover 28 being in an excessively low position, further research was conducted related to the preferred position setting, and the following insights were obtained: the aforementioned structure where D1 (the difference in height between the upper surface 22a1 of the first outer blade 22A and the upper surface 22a2 of the second outer blade 22B) and D2 (the difference in height between the upper surface 22a2 of the second outer blade 22B and the upper surface 28c of the outer blade cover 28) is D2≤D1×3 is preferred; furthermore, the aforementioned structure where D1 and D2 are D2≤D1×2 is more preferred. According to this structure, the following problems can be solved. Specifically, although the skin on the side of the second outer blade 22B is prone to damage because the circumferential width W2 of the hair inlet 22c3 of the second outer blade 22B is set wider than the circumferential width W1 of the hair inlet 22c1 of the first outer blade 22A as described above, this problem can be solved by setting the above-mentioned height difference structure, that is, the damage can be suppressed and reduced.

[0063] Furthermore, as a variation, the structure can be configured as follows (not shown): the upper surface 28c of the outer blade cover 28 (including the decorative plate 29) is positioned higher than the upper surface 22a2 of the second outer blade 22B. That is, the upper surface 28c is positioned lower than the upper surface 22a1 of the first outer blade 22A and higher than the upper surface 22a2 of the second outer blade 22B. According to this structure, compared to the aforementioned structure, the effect of using the outer blade cover 28 to suppress skin encroachment and thus achieve damage suppression can be further improved.

[0064] As explained above, the rotary electric razor 1 according to the present invention, even with a simple structure in which the inner blade 42 rotates only in one direction (i.e., it does not have a mechanism for rotating in both forward and reverse directions), can achieve both damage suppression and sharpness improvement.

[0065] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. In particular, an example of a rotary electric razor having a combination of three sets of outer and inner blades (blade units) has been described, but it is not limited thereto. That is, it can also be applied to rotary electric razors (not shown) having one or two sets of blade units with the above structure.

Claims

1. A rotary electric shaver comprising a blade unit having an outer blade having a plurality of hair inlets and an inner blade that rotates while sliding in contact with the inner surface of the outer blade, characterized in that, The inner blade has a plurality of first small blades standing upright from the base surface, and a plurality of second small blades standing upright from the base surface. The first small blade has a first tip tip at its front end, which is formed in the direction of rotation towards the upper end and is capable of cutting hair that enters the hair inlet. The second blade, facing upwards, has a second tip at its front end capable of cutting hair that enters the hair inlet, formed in the direction of rotation towards its upper end. The first front tip has a relatively small rake angle α1, while the second front tip has a relatively large rake angle α2.

2. The rotary electric shaver according to claim 1, characterized in that, The first small blade is disposed on the outer peripheral side of the base surface. The second small blade is disposed on the inner circumferential side of the base surface. The outer blade has a first outer blade located at a position corresponding to the first small blade, and a second outer blade located at a position corresponding to the second small blade, wherein the upper surface of the first outer blade is formed at a relatively high position, and the upper surface of the second outer blade is formed at a relatively low position.

3. The rotary electric shaver according to claim 1 or 2, characterized in that, The angle α1 is formed as 30°≤α1≤90°, and the angle α2 is formed as 70°≤α2≤90°.

4. The rotary electric shaver according to claim 2, characterized in that, In the outer blades, the circumferential width of the hair inlet of the first outer blade is relatively narrow, and the circumferential width of the hair inlet of the second outer blade is relatively wide.

5. The rotary electric shaver according to claim 2, characterized in that, The outer blade has an outer blade cover embedded in the radial center, and the upper surface of the outer blade cover is formed at a position lower than the upper surface of the second outer blade. The rotary electric shaver is configured such that, when the height difference between the upper surface of the first outer blade and the upper surface of the second outer blade is set as D1, and the height difference between the upper surface of the second outer blade and the upper surface of the outer blade cover is set as D2, D2 ≤ D1 × 3.

6. The rotary electric shaver according to claim 2, characterized in that, The outer blade has an outer blade cover embedded in the radial center, and the upper surface of the outer blade cover is formed at a position lower than the upper surface of the first outer blade and higher than the upper surface of the second outer blade.

7. The rotary electric shaver according to claim 1 or 2, characterized in that, The first small blade is a structure that stands upright at an acute angle from the base surface, facing the direction of rotation. The second small blade is a structure that stands upright at an acute angle from the base surface in a direction opposite to the direction of rotation.

8. The rotary electric shaver according to claim 7, characterized in that, The first and second small blades are formed in a shape that is symmetrical about the front and back along the direction of rotation.

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