Rotary damper and valve, and method for preventing torque reduction of rotary damper due to valve wear

Abstract

To prevent reduction in torque of a rotary damper due to wearing of a valve.SOLUTION: A rotary damper comprises a valve (3) including: a first end face (3a) opposed to a first face (4a) of an oil chamber (4) closing one end; a second end face (3b) opposed to a second face (4b) of the oil chamber (4) closing the other end; a back face (3c) opposed to a curved face (4c) of the oil chamber (4); and a valve part (3d) for closing an oil path (5) formed between the valve and a rotor (2). The valve prevents an oil, which is injected to the oil chamber (4) by closing the oil path (5) with the valve part (3d), from flowing back through the oil path (5). The valve (3) includes recessed and projected parts (3k and 3l) on the back face (3c). The recessed part (3k) in the recessed and projected parts (3k and 3l) forms a clearance (6) between the recessed part and the curved face (4c). A cross-sectional area of the clearance (6) is reduced by wearing the projected part (3l) in the recessed and projected parts (3k and 3l), and functions of the valve part (3d) are prevented from being impaired by wearing the projected part (3l).SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a rotary damper, a valve, and a method for preventing a decrease in torque of the rotary damper due to wear of the valve.

Background Art

[0002] Conventionally, there is known a rotary damper including a first end face facing a first surface closing one end of an oil chamber, a second end face facing a second surface closing the other end of the oil chamber, a back face facing a curved surface of the oil chamber, and a valve portion closing an oil passage formed between the back face and a rotor, the valve portion preventing oil injected into the oil chamber from flowing back through the oil passage by closing the oil passage.

[0003] For example, FIGS. 3 to 7 of International Publication No. 2012 / 141242 disclose a rotary damper including a first end face facing a first surface (bottom surface of plug 30) closing one end of an oil chamber (chambers 71 and 72), a second end face facing a second surface (upper surface of end wall 11) closing the other end of the oil chamber, a back face facing a curved surface (inner peripheral surface of peripheral wall 12) of the oil chamber, and a valve portion (protrusion 84b) closing an oil passage (first groove 81) formed between the back face and a rotor, the valve portion preventing oil injected into the oil chamber from flowing back through the oil passage by closing the oil passage.

[0004] However, in a conventional rotary damper, while the first end face of the valve contacts the first surface of the oil chamber and the back face of the valve does not contact the curved surface of the oil chamber, the rotor or the housing rotates, or while the second end face of the valve contacts the second surface of the oil chamber and the back face of the valve does not contact the curved surface of the oil chamber, the rotor or the housing rotates. Therefore, there is a problem that the valve wears, and thereby the torque decreases.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0006] The problem to be solved by the present invention is to prevent a decrease in the torque of a rotary damper due to wear of a valve.

MEANS FOR SOLVING THE PROBLEM

[0007] To solve the above problems, the present invention provides the following rotary damper, valve, and method for preventing a decrease in the torque of the rotary damper due to wear of the valve. 1. A valve having a first end face facing a first surface that closes one end of an oil chamber, a second end face facing a second surface that closes the other end of the oil chamber, a back face facing a curved surface of the oil chamber, and a valve portion that closes an oil passage formed between the valve and a rotor, wherein the valve portion prevents oil injected into the oil chamber from flowing back through the oil passage by closing the oil passage, the valve has irregularities on the back face, a recess of the irregularities forms a gap with the curved surface, a cross-sectional area of the gap is reduced by wear of a convex portion of the irregularities, and a function of the valve portion is not impaired by wear of the convex portion characterized rotary damper. 2. A valve having a first end face facing a first surface that closes one end of an oil chamber, a second end face facing a second surface that closes the other end of the oil chamber, a back face facing a curved surface of the oil chamber, and a valve portion that closes an oil passage formed between the valve and a rotor, wherein the valve portion prevents oil injected into the oil chamber from flowing back through the oil passage by closing the oil passage, the valve has irregularities on the back face, a recess of the irregularities forms a gap with the curved surface, the oil has a viscosity sufficient to prevent a decrease in torque due to the gap, The cross-sectional area of the gap is reduced by wear of the convex portion of the unevenness, and the function of the valve portion is not impaired by wear of the convex portion characterized rotary damper. 3. A valve for a rotary damper, The valve has a first end face facing a first face that closes one end of the oil chamber, a second end face facing a second face that closes the other end of the oil chamber, a back face facing the curved surface of the oil chamber, a valve portion that closes an oil passage formed between the valve and a rotor, and unevenness formed on the back face, and prevents oil injected into the oil chamber from flowing back through the oil passage when the valve portion closes the oil passage, a gap is formed between the concave portion of the unevenness and the curved surface, The cross-sectional area of the gap is reduced by wear of the convex portion of the unevenness, and the function of the valve portion is not impaired by wear of the convex portion characterized valve. 4. A method for preventing a decrease in torque of a rotary damper due to wear of a valve, As the valve, it has a first end face facing a first face that closes one end of the oil chamber, a second end face facing a second face that closes the other end of the oil chamber, a back face facing the curved surface of the oil chamber, a valve portion that closes an oil passage formed between the valve and a rotor, and unevenness formed on the back face, and prevents oil injected into the oil chamber from flowing back through the oil passage when the valve portion closes the oil passage, a gap is formed between the concave portion of the unevenness and the curved surface, the cross-sectional area of the gap is reduced by wear of the convex portion of the unevenness, and the function of the valve portion is not impaired by wear of the convex portion, preventing a decrease in torque due to an increase in the gap between the second end face and the second face due to wear of the first end face or an increase in the gap between the first end face and the first face due to wear of the second end face by reducing the cross-sectional area of the gap due to wear of the convex portion. 5. A method for preventing a decrease in torque of a rotary damper due to wear of a valve, As the valve, a first end face facing a first face that closes one end of the oil chamber, a second end face facing a second face that closes the other end of the oil chamber, a back face facing the curved surface of the oil chamber, a valve portion that closes an oil passage formed between the valve and a rotor, and irregularities formed on the back face, wherein when the valve portion closes the oil passage, oil injected into the oil chamber is prevented from flowing back through the oil passage, a gap is formed between the concave portion of the irregularities and the curved surface, the cross-sectional area of the gap is reduced by wear of the convex portion of the irregularities, and the function of the valve portion is not impaired by wear of the convex portion, the oil has a viscosity sufficient to prevent a decrease in torque due to the gap, A method characterized by preventing a decrease in torque caused by an increase in the gap between the second end face and the second face due to wear of the first end face or an increase in the gap between the first end face and the first face due to wear of the second end face by reducing the cross-sectional area of the gap due to wear of the convex portion.

Advantages of the Invention

[0008] According to the rotary damper of the present invention, irregularities are formed on the back face of the valve facing the curved surface of the oil chamber, a gap is formed between the concave portion of the irregularities and the curved surface, the cross-sectional area of the gap is reduced by wear of the convex portion of the irregularities, and the function of the valve portion of the valve is not impaired by wear of the convex portion. Therefore, it is possible to prevent a decrease in torque due to wear of the valve. According to the valve of the present invention, irregularities are formed on the back face facing the curved surface of the oil chamber, a gap is formed between the concave portion of the irregularities and the curved surface, the cross-sectional area of the gap is reduced by wear of the convex portion of the irregularities, and the function of the valve portion is not impaired by wear of the convex portion. Therefore, it is possible to prevent a decrease in torque of the rotary damper due to wear of the valve. According to the method of the present invention, as the valve, a first end face facing a first surface closing one end of the oil chamber, a second end face facing a second surface closing the other end of the oil chamber, a back face facing the curved surface of the oil chamber, a valve portion closing an oil passage formed between the valve and a rotor, and unevenness formed on the back face, the oil injected into the oil chamber by the valve portion closing the oil passage is prevented from flowing back through the oil passage, a gap is formed between the concave portion of the unevenness and the curved surface, the cross-sectional area of the gap is reduced by wear of the convex portion of the unevenness, and the function of the valve portion is not impaired by wear of the convex portion. In order to prevent a decrease in torque due to an increase in the gap between the second end face and the second surface due to wear of the first end face or an increase in the gap between the first end face and the first surface due to wear of the second end face, a decrease in torque of the rotary damper due to wear of the valve can be prevented by reducing the cross-sectional area of the gap due to wear of the convex portion.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 9

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Figure 11

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Figure 15

Figure 16

Figure 17

Figure 18

Embodiment for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.

Embodiment

[0011] As shown in FIG. 1, the rotary damper according to the embodiment includes a housing (1), a rotor (2), and a valve (3).

[0012] As shown in FIGS. 1 and 2, the housing (1) includes a cylindrical peripheral wall (1a), a lid (1b) that closes one end of the peripheral wall (1a), an end wall (1c) that closes the other end of the peripheral wall (1a), a partition wall (1d) that projects from the inner peripheral surface of the peripheral wall (1a), and a flange (1e) that projects from the outer peripheral surface of the peripheral wall (1a). As shown in FIG. 2, the partition wall (1d) is a partition that separates two oil chambers (4) formed inside the housing (1). Oil is injected into each oil chamber (4). The flange (1e) is connected to an object that prevents the rotation of the housing (1) or an object that transmits a rotational force to the housing (1).

[0013] As shown in FIG. 2, the rotor (2) includes a shaft portion (2a) and protrusions (2b) that project from the outer peripheral surface of the shaft portion (2a). The shaft portion (2a) is connected to an object that transmits a rotational force to the rotor (2) or an object that prevents the rotation of the rotor (2). The protrusions (2b) are disposed in each oil chamber (4). The protrusions (2b) have longitudinal grooves (2c) at their tips.

[0014] As shown in FIG. 2, the valve (3) is installed between the peripheral wall (1a) of the housing (1) and the protrusions (2b) of the rotor (2). As shown in FIGS. 4 to 10, the valve (3) has a first end face (3a), a second end face (3b), a back face (3c), and a valve portion (3d).

[0015] As shown in FIG. 1, the first end face (3a) of the valve (3) faces the first face (4a) that closes one end of the oil chamber (4) (that is, the bottom face of the lid (1b) in the embodiment), the second end face (3b) of the valve (3) faces the second face (4b) that closes the other end of the oil chamber (4) (that is, the upper face of the end wall (1c) in the embodiment), and the back face (3c) of the valve (3) faces the curved face (4c) of the oil chamber (4) (that is, the inner peripheral surface of the peripheral wall (1a) in the embodiment).

[0016] As shown in FIGS. 2, 4 to 7, 9 and 10, the valve (3) adopted in the embodiment has a main body portion (3e) installed between the tip of the protrusion (2b) of the rotor (2) and the peripheral wall (1a) of the housing (1), a first protrusion (3f) protruding from the main body portion (3e) on one end side of the main body portion (3e), and a second protrusion (3g) protruding from the main body portion (3e) on the other end side of the main body portion (3e). As shown in FIGS. 1 and 2, the first protrusion (3f) and the second protrusion (3g) are arranged in the longitudinal groove (2c) formed in the rotor (2) and are movable in the circumferential direction in the longitudinal groove (2c). As shown in FIGS. 4, 7, 9 and 10, the valve portion (3d) of the valve (3) is formed between the first protrusion (3f) and the second protrusion (3g).

[0017] As shown in FIGS. 4, 7 and 10, the valve (3) has a first groove (3h) extending from the left side surface of the main body portion (3e) to the left side surface of the valve portion (3d), a second groove (3i) extending from the left side surfaces of the first protrusion (3f) and the second protrusion (3g) to the right side surfaces of the first protrusion (3f) and the second protrusion (3g), and a third groove (3j) extending from the right side surface of the valve portion (3d) to the right side surface of the main body portion (3e).

[0018] As shown in FIG. 2, the rotary damper according to the embodiment has an oil passage (5) formed between the valve (3) and the rotor (2). This oil passage (5) is composed of the gap between the first groove (3h) of the valve (3) and the tip of the protrusion (2b) of the rotor (2), the gap between the second groove (3i) of the valve (3) and the longitudinal groove (2c) formed in the rotor (2), and the gap between the third groove (3j) of the valve (3) and the tip of the protrusion (2b) of the rotor (2).

[0019] As shown in Fig. 2, the valve (3) adopted in the embodiment has a valve portion (3d) that closes the oil passage (5) formed between it and the rotor (2). When the valve portion (3d) closes the oil passage (5), it prevents the oil injected into the oil chamber (4) from flowing back through the oil passage (5). Specifically, as shown in Fig. 3, when the rotor (2) rotates counterclockwise or the housing (1) rotates clockwise, the valve portion (3d) of the valve (3) moves away from the protrusion (2b) of the rotor (2), so the oil flows through the oil passage (5). On the other hand, as shown in Fig. 2, when the rotor (2) rotates clockwise or the housing (1) rotates counterclockwise, the valve portion (3d) of the valve (3) contacts the protrusion (2b) of the rotor (2), thereby blocking the flow of oil and preventing the oil from flowing back through the oil passage (5).

[0020] The rotary damper according to the embodiment generates an effective torque when the oil passage (5) is closed by the valve (3). However, when the rotor (2) or the housing (1) rotates, friction occurs between the first end face (3a) of the valve (3) and the first face (4a) of the oil chamber (4), and between the back face (3c) of the valve (3) and the curved face (4c) of the oil chamber (4), or friction occurs between the second end face (3b) of the valve (3) and the second face (4b) of the oil chamber (4), and between the back face (3c) of the valve (3) and the curved face (4c) of the oil chamber (4). Therefore, the valve (3) wears out as the rotor (2) or the housing (1) repeatedly rotates. When the first end face (3a) of the valve (3) wears out, the gap between the second end face (3b) of the valve (3) and the second face (4b) of the oil chamber (4) expands, and when the second end face (3b) of the valve (3) wears out, the gap between the first end face (3a) of the valve (3) and the first face (4a) of the oil chamber (4) expands. As a result, the flow rate of the oil passing through these gaps increases, and the torque decreases accordingly.

[0021] As shown in FIGS. 5 and 8 to 10, the valve (3) adopted in the embodiment has irregularities (3k, 3l) on the back surface (3c). As shown in FIGS. 1 to 3, the concave portion (3k) of the irregularities (3k, 3l) forms a gap (6) between the curved surface (4c) of the oil chamber (4). Since oil can pass through this gap (6) when the valve portion (3d) of the valve (3) closes the oil passage (5), this gap (6) reduces torque. However, the oil adopted in the embodiment has a viscosity sufficient to prevent a reduction in torque due to the gap (6). That is, the viscosity of the oil adopted in the embodiment is set higher than the viscosity of the oil used in the comparative example so that it can generate torque equivalent to that of the comparative example described later.

[0022] The cross-sectional area of the gap (6) formed between the valve (3) and the peripheral wall (1a) of the housing (1) by the concave portion (3k) is reduced by the wear of the convex portion (3l) of the irregularities (3k, 3l). As will be described later, in the rotary damper according to the embodiment, the reduction in torque due to the wear of the first end surface (3a) and / or the second end surface (3b) is compensated by the increase in torque due to the reduction in the cross-sectional area of the gap (6), so that the reduction in torque due to the wear of the valve (3) can be reduced.

[0023] The function of the valve portion (3d) of the valve (3) is not impaired by the wear of the convex portion (3l). The "function" of the valve portion (3d) means the ability of the valve portion (3d) to close the oil passage (5). In the embodiment, the cross-sectional area of the oil passage (5) (specifically, the cross-sectional area of the gap between the first groove (3h) of the valve (3) and the tip of the protrusion (2b) of the rotor (2)) is enlarged by the wear of the convex portion (3l). However, the left side surface of the valve portion (3d) of the valve (3) adopted in the embodiment has a sufficient area to completely close the oil passage (5) even after the cross-sectional area of the oil passage (5) is enlarged. Therefore, the function of the valve portion (3d) is not impaired by the wear of the convex portion (3l). According to the valve (3) having this valve portion (3d), it is possible to prevent oil from flowing back through the oil passage (5) and to enhance the compensation effect due to the reduction in the cross-sectional area of the gap (6).

[0024] The embodiments provide a method for preventing a decrease in the torque of a rotary damper due to wear of the valve (3). This method is characterized in that a decrease in torque due to an increase in the gap between the second end face (3b) of the valve (3) and the second face (4b) of the oil chamber (4) due to wear of the first end face (3a) of the valve (3), or due to an increase in the gap between the first end face (3a) of the valve (3) and the first face (4a) of the oil chamber (4) due to wear of the second end face (3b) of the valve (3) is prevented by a reduction in the cross-sectional area of the gap (6) due to wear of the convex portion (3l) of the valve (3).

[0025] The effects of this method will be described by comparing the embodiments with comparative examples. As shown in FIGS. 11 and 12, the valve (3') employed in the comparative example differs from the valve (3) employed in the embodiments in that no unevenness is formed on its back surface (3c'). Other configurations of the comparative example are the same as those of the embodiments.

[0026] In the graphs shown in FIGS. 13 to 18, "flow rate" is the estimated amount of oil passing through a specific location per unit time, "number of operations" is the number of times the rotor (2) is rotated in one direction (the direction in which the oil passage (5) is closed), and "N1" is the number of operations when wear occurs on the valves (3, 3'). In the graphs shown in FIGS. 15 and 18, "torque" is the torque generated when the rotor (2) is rotated in one direction (the direction in which the oil passage (5) is closed). In the graphs shown in FIGS. 16 to 18, "N2" is the number of operations when the convex portion (3l) is completely worn out.

[0027] As shown in FIG. 13, in the comparative example, after wear occurs on the first end face (3a') or the second end face (3b') of the valve (3'), as the number of operations increases from N1, the wear of the first end face (3a') or the second end face (3b') of the valve (3') progresses, so the oil flow rate increases.

[0028] As shown in Fig. 16, in the embodiment as well as in the comparative example, after wear occurs on the first end face (3a) or the second end face (3b) of the valve (3), as the number of operations increases from N1, the wear on the first end face (3a) or the second end face (3b) of the valve (3) progresses, so the oil flow rate increases. Note that since the viscosity of the oil used in the embodiment is higher than the viscosity of the oil used in the comparative example, the initial flow rate of the embodiment is less than the initial flow rate of the comparative example.

[0029] As shown in Fig. 14, in the comparative example, wear occurs on the back face (3c') of the valve (3'), and as the number of operations increases from N1, even if the wear on the back face (3c') of the valve (3') progresses, the oil flow rate passing between the back face (3c') of the valve (3') and the curved surface (4c) of the oil chamber (4) does not change from the initial value.

[0030] In contrast to the comparative example, in the embodiment, as shown in Fig. 17, when wear occurs on the convex portion (3l) of the valve (3) and the number of operations increases from N1, and as the wear on the convex portion (3l) of the valve (3) progresses, the cross-sectional area of the gap (6) between the concave portion (3k) of the valve (3) and the curved surface (4c) of the oil chamber (4) decreases according to the progress of the wear. Therefore, the oil flow rate passing between the back face (3c) of the valve (3) and the curved surface (4c) of the oil chamber (4) decreases. The decrease in the flow rate continues until the number of operations reaches N2, that is, until the convex portion (3l) of the valve (3) is completely worn out.

[0031] As a result, as shown in Fig. 15, in the comparative example, after wear occurs on the valve (3'), the torque decreases as the number of operations increases from N1.

[0032] On the other hand, in the embodiment, as shown in Fig. 18, even after wear occurs on the valve (3), until the number of operations reaches N2, that is, until the convex portion (3l) of the valve (3) is completely worn out, the torque does not decrease from the initial value. Therefore, the present invention can effectively prevent the decrease in the torque of the rotary damper due to the wear of the valve (3).

Explanation of Reference Numerals

[0033] 1 Housing 1a Peripheral wall 1b Cover 1c End wall 1d Partition wall 1e Flange 2 Rotor 2a Shaft portion 2b Projection 2c Longitudinal groove 3 Valve 3a First end face 3b Second end face 3c Back surface 3d Valve portion 3e Body portion 3f First protrusion 3g Second protrusion 3h First groove 3i Second groove 3j Third groove 3k Recess 3l Protrusion 4 Oil chamber 4a First surface 4b Second surface 4c Curved surface 5 Oil passage 6 Gap

Claims

1. A first end face facing a first surface that closes one end of the oil chamber, a second end face facing a second surface that closes the other end of the oil chamber, a back face facing the curved surface of the oil chamber, and a valve portion that closes an oil passage formed between the valve portion and a rotor, and the valve portion closes the oil passage to prevent oil injected into the oil chamber from flowing back through the oil passage, and a valve is provided. The valve has irregularities on the back face. A gap is formed between the concave portion of the irregularities and the curved surface. The cross-sectional area of the gap is reduced by wear of the convex portion of the irregularities. The function of the valve portion is not impaired by wear of the convex portion. A rotary damper characterized by the above.

2. The rotary damper according to claim 1, wherein the oil has a viscosity sufficient to prevent a decrease in torque due to the gap.

3. A valve for a rotary damper, The valve has a first end face facing a first surface that closes one end of the oil chamber, a second end face facing a second surface that closes the other end of the oil chamber, a back face facing the curved surface of the oil chamber, a valve portion that closes an oil passage formed between the valve portion and a rotor, and irregularities formed on the back face, and the valve portion closes the oil passage to prevent oil injected into the oil chamber from flowing back through the oil passage. A gap is formed between the concave portion of the irregularities and the curved surface. The cross-sectional area of the gap is reduced by wear of the convex portion of the irregularities. The function of the valve portion is not impaired by wear of the convex portion. A valve characterized by the above.

4. A method for preventing a decrease in torque of a rotary damper due to wear of a valve, As the valve, a first end face facing a first surface that closes one end of the oil chamber, a second end face facing a second surface that closes the other end of the oil chamber, a back face facing the curved surface of the oil chamber, a valve portion that closes an oil passage formed between the valve portion and a rotor, and irregularities formed on the back face, and the valve portion closes the oil passage to prevent oil injected into the oil chamber from flowing back through the oil passage, a gap is formed between the concave portion of the irregularities and the curved surface, the cross-sectional area of the gap is reduced by wear of the convex portion of the irregularities, and the function of the valve portion is not impaired by wear of the convex portion is used. A method characterized by preventing a decrease in torque due to an increase in the gap between the second end face and the second surface due to wear of the first end face or an increase in the gap between the first end face and the first surface due to wear of the second end face by reducing the cross-sectional area of the gap due to wear of the convex portion.

5. The method according to claim 4, characterized in that the oil has a viscosity sufficient to prevent a decrease in torque due to the gap.

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